text: Low-surface-brightness (LSB) galaxies have a much larger visible mass deficit than others. This property simplifies the disentanglement of the dark and visible matter contributions to the rotation curves.

entity_name: Low-surface-brightness galaxy

text: Low-surface-brightness

text: (LSB) galaxies have a much larger visible mass deficit than others. This property simplifies the disentanglement of the dark and visible matter contributions to the rotation curves.

text: A reflection is a map that transforms an object into its mirror image with respect to a "mirror", which is a hyperplane of fixed points in the geometry. For example, a reflection of the small Latin letter p with respect to a vertical line would look like a "q". In order to reflect a planar figure one needs the "mirror" to be a line (axis of reflection or axis of symmetry), while for reflections in the three-dimensional space one would use a plane (the plane of reflection or symmetry) for a mirror. Reflection may be considered as the limiting case of inversion as the radius of the reference circle increases without bound.

text: A reflection is a

entity_name: Function (mathematics)

text: map

text: that transforms an object into its

entity_name: Mirror image

text: mirror image

text: with respect to a "mirror", which is a hyperplane of fixed points in the geometry. For example, a reflection of the small Latin letter p with respect to a vertical line would look like a "q". In order to reflect a planar figure one needs the "mirror" to be a line (axis of reflection or axis of symmetry), while for reflections in the three-dimensional space one would use a

entity_name: Plane (geometry)

text: plane

text: (the plane of reflection or symmetry) for a mirror. Reflection may be considered as the limiting case of

entity_name: Inversive geometry

entity_section: Circle inversion

text: inversion

text: as the radius of the reference circle increases without bound.

text: On yeshiva.org.il, Chardal is described as, "The people who classify themselves as 'Charedi Leumi', or 'Chardal', try to keep the Mitzvot strictly, Kalah Kechamurah [light and weighty matters alike], while being involved in the national life in the state, and in the settling Eretz Yisrael."

text: The continuously variable transmission (CVT) is a transmission in which the ratio of the rotational speeds of two shafts, as the input shaft and output shaft of a vehicle or other machine, can be varied continuously within a given range, providing an infinite number of possible ratios. The CVT allows the driver or a computer to select the relationship between the speed of the engine and the speed of the wheels within a continuous range. This can provide even better fuel economy if the engine constantly runs at a single speed. The transmission is, in theory, capable of a better user experience, without the rise and fall in speed of an engine, and the jerk felt when changing gears poorly.

text: Quasars have all the properties of other active galaxies such as Seyfert galaxies, but are more powerful: their radiation is partially 'nonthermal' (i.e., not due to  black body radiation), and approximately 10 percent are observed to also have jets and lobes like those of radio galaxies that also carry significant (but poorly understood) amounts of energy in the form of particles moving at relativistic speeds. Extremely high energies might be explained by several mechanisms (see Fermi acceleration and Centrifugal mechanism of acceleration). Quasars can be detected over the entire observable electromagnetic spectrum including radio, infrared, visible light, ultraviolet, X-ray and even gamma rays. Most quasars are brightest in their rest-frame near-ultraviolet wavelength of 121.6 nm Lyman-alpha emission line of hydrogen, but due to the tremendous redshifts of these sources, that peak luminosity has been observed as far to the red as 900.0 nm, in the near infrared. A minority of quasars show strong radio emission, which is generated by jets of matter moving close to the speed of light. When looked at down the jet, these appear as blazars and often have regions that appear to move away from the center faster than the speed of light (superluminal expansion). This is an optical illusion due to the properties of special relativity.

text: Quasars have all the properties of other active galaxies such as

entity_name: Seyfert galaxy

text: Seyfert galaxies

text: , but are more powerful: their

entity_name: Radiation

text: radiation

text: is partially 'nonthermal' (i.e., not due to

entity_name: Black body

text: black body

text: radiation), and approximately 10 percent are observed to also have jets and lobes like those of

entity_name: Radio galaxy

text: radio galaxies

text: that also carry significant (but poorly understood) amounts of energy in the form of particles moving at

entity_name: Relativistic speed

text: relativistic speed

text: s. Extremely high energies might be explained by several mechanisms (see

entity_name: Fermi acceleration

text: Fermi acceleration

text: and

entity_name: Centrifugal mechanism of acceleration

text: Centrifugal mechanism of acceleration

text: ). Quasars can be detected over the entire observable

entity_name: Electromagnetic spectrum

text: electromagnetic spectrum

text: including

entity_name: Radio wave

text: radio

entity_name: Infrared

text: infrared

entity_name: Light

text: visible light

entity_name: Ultraviolet

text: ultraviolet

entity_name: X-ray

text: X-ray

text: and even

entity_name: Gamma ray

text: gamma ray

text: s. Most quasars are brightest in their rest-frame near-ultraviolet wavelength of 121.6

entity_name: Nanometre

text: nm

entity_name: Lyman series

text: Lyman-alpha

text: emission line of hydrogen, but due to the tremendous redshifts of these sources, that peak luminosity has been observed as far to the red as 900.0 nm, in the near infrared. A minority of quasars show strong radio emission, which is generated by jets of matter moving close to the speed of light. When looked at down the jet, these appear as

entity_name: Blazar

text: blazar

text: s and often have regions that appear to move away from the center faster than the speed of light (

entity_name: Faster-than-light

text: superluminal

text: expansion). This is an optical illusion due to the properties of

entity_name: Special relativity

text: special relativity

method: Bert-DRMMTKS

text: Unlike a compound light microscope, illumination in a stereo microscope most often uses reflected illumination rather than transmitted (diascopic) illumination, that is, light reflected from the surface of an object rather than light transmitted through an object. Use of reflected light from the object allows examination of specimens that would be too thick or otherwise opaque for compound microscopy. Some stereo microscopes are also capable of transmitted light illumination as well, typically by having a bulb or mirror beneath a transparent stage underneath the object, though unlike a compound microscope, transmitted illumination is not focused through a condenser in most systems. Stereoscopes with specially-equipped illuminators can be used for dark field microscopy, using either reflected or transmitted light.

text: Unlike a compound

entity_name: Optical microscope

text: light microscope

text: , illumination in a stereo microscope most often uses

entity_name: Reflection (physics)

text: reflected

text: illumination rather than

entity_name: Transmission coefficient

entity_section: Optics

text: transmitted

text: (diascopic) illumination, that is, light reflected from the surface of an object rather than light transmitted through an object. Use of reflected light from the object allows examination of specimens that would be too thick or otherwise opaque for compound microscopy. Some stereo microscopes are also capable of transmitted light illumination as well, typically by having a bulb or mirror beneath a transparent stage underneath the object, though unlike a compound microscope, transmitted illumination is not focused through a condenser in most systems. Stereoscopes with specially-equipped illuminators can be used for

entity_name: Dark field microscopy

text: dark field microscopy

text: , using either reflected or transmitted light.

text: Pigments appear the colors they are because they selectively reflect and absorb certain wavelengths of visible light. White light is a roughly equal mixture of the entire spectrum of visible light with a wavelength in a range from about 375 or 400 nanometers to about 760 or 780 nm. When this light encounters a pigment, parts of the spectrum are absorbed by the molecules or ions of the pigment. In organic pigments such as diazo or phthalocyanine compounds the light is absorbed by the conjugated systems of double bonds in the molecule. Some of the inorganic pigments such as vermilion (mercury sulfide) or cadmium yellow (cadmium sulfide) absorb light by transferring an electron from the negative ion (S) to the positive ion (Hg or Cd). Such compounds are designated as charge-transfer complexes, with broad absorption bands that subtract most of the colors of the incident white light. The other wavelengths or parts of the spectrum are reflected or scattered. The new reflected light spectrum creates the appearance of a color. Pigments, unlike fluorescent or phosphorescent substances, can only subtract wavelengths from the source light, never add new ones.

text: Pigments appear the colors they are because they selectively reflect and absorb certain wavelengths of

text: visible light

entity_name: White

text: White light

text: is a roughly equal mixture of the entire spectrum of visible light with a

entity_name: Wavelength

text: wavelength

text: in a range from about 375 or 400

text: nanometer

text: s to about 760 or 780 nm. When this light encounters a pigment, parts of the spectrum are

entity_name: Absorption (electromagnetic radiation)

text: absorbed

text: by the molecules or ions of the pigment. In organic pigments such as

entity_name: Azo compound

text: diazo

text: or

entity_name: Phthalocyanine

text: phthalocyanine

text: compounds the light is absorbed by the

entity_name: Conjugated system

entity_section: Conjugated systems in pigments

text: conjugated systems

text: of

entity_name: Double bond

text: double bond

text: s in the molecule. Some of the inorganic pigments such as

entity_name: Vermilion

text: vermilion

text: (mercury sulfide) or

entity_name: Cadmium pigments

text: cadmium yellow

text: (cadmium sulfide) absorb light by transferring an electron from the negative ion (S) to the positive ion (Hg or Cd). Such compounds are designated as

entity_name: Charge-transfer complex

text: charge-transfer complex

text: es, with broad

entity_name: Absorption band

text: absorption band

text: s that subtract most of the colors of the incident white light. The other wavelengths or parts of the spectrum are reflected or scattered. The new reflected light spectrum creates the appearance of a

entity_name: Color

text: color

text: . Pigments, unlike

entity_name: Fluorescence

text: fluorescent

text: or

entity_name: Phosphorescence

text: phosphorescent

text: substances, can only

entity_name: Subtractive color

text: subtract

text: wavelengths from the source light, never add new ones.

method: UNH-qee

text: These are optical instruments for measurement of the absorption of light of a given wavelength (or a given range of wavelengths) of coloured substances in solution. From the light absorption, Beer's law makes it possible to calculate the concentration of the coloured substance in the solution. Due to its wide range of application and its reliability and robustness, the photometer has become one of the principal instruments in biochemistry and analytical chemistry. Absorption photometers for work in aqueous solution work in the ultraviolet and visible ranges, from wavelength around 240 nm up to 750 nm.

text: These are optical instruments for measurement of the absorption of light of a given wavelength (or a given range of wavelengths) of coloured substances in solution. From the light absorption,

entity_name: Beer–Lambert law

text: Beer's law

text: makes it possible to calculate the concentration of the coloured substance in the solution. Due to its wide range of application and its reliability and robustness, the photometer has become one of the principal instruments in

entity_name: Biochemistry

text: biochemistry

text: and

entity_name: Analytical chemistry

text: analytical chemistry

text: . Absorption photometers for work in aqueous solution work in the ultraviolet and visible ranges, from wavelength around 240 nm up to 750 nm.

text: Sila–Nunam is very red in visible light and has a flat featureless spectrum in the near-infrared. There are no water ice absorption bands in its near-infrared spectrum, which resembles that of Ixion.

text: Sila–Nunam is very red in visible light and has a flat featureless spectrum in the

entity_section: Regions within the infrared

text: near-infrared

text: . There are no water ice absorption bands in its near-infrared spectrum, which resembles that of

entity_name: 28978 Ixion

text: Ixion

text: Visible light can be seen by the naked eye (and thus forms images that people can look at), but it does not penetrate most objects (only translucent ones). In contrast, X-rays can penetrate a wider variety of objects (such as the human body), but they are invisible to the naked eye. To take advantage of the penetration for image-forming purposes, one must somehow convert the X-rays' intensity variations (which correspond to material contrast and thus image contrast) into a form that is visible. Classic film-based radiography achieves this by the variable chemical changes that the X-rays induce in the film, and classic fluoroscopy achieves it by fluorescence, in which certain materials convert X-ray energy (or other parts of the spectrum) into visible light. This use of fluorescent materials to make a viewing scope is how fluoroscopy got its name.

text: Visible light

text: can be seen by the naked eye (and thus forms images that people can look at), but it does not penetrate most objects (only

entity_name: Transparency and translucency

text: translucent

text: ones). In contrast, X-rays can penetrate a wider variety of objects (such as the human body), but they are invisible to the naked eye. To take advantage of the penetration for image-forming purposes, one must somehow convert the X-rays'

entity_name: Intensity (physics)

text: intensity

text: variations (which correspond to material contrast and thus image contrast) into a form that is visible. Classic film-based radiography achieves this by the variable chemical changes that the X-rays induce in the

entity_name: Photographic film

text: film

text: , and classic fluoroscopy achieves it by

text: fluorescence

text: , in which certain materials convert X-ray energy (or other parts of the

text: spectrum

text: ) into visible light. This use of fluorescent materials to make a

text: viewing scope

text: is how fluoroscopy got its name.

text: Newton built the first functioning reflecting telescope and developed a theory of color, published in Opticks, based on the observation that a prism decomposes white light into the many colours forming the visible spectrum. While Newton explained light as being composed of tiny particles, a rival theory of light which explained its behavior in terms of waves was presented in 1690 by Christiaan Huygens. However, the belief in the mechanistic philosophy coupled with Newton's reputation meant that the wave theory saw relatively little support until the 19th century. Newton also formulated an empirical law of cooling, studied the speed of sound, investigated power series, demonstrated the generalised binomial theorem and developed a method for approximating the roots of a function. His work on infinite series was inspired by Simon Stevin's decimals. Most importantly, Newton showed that the motions of objects on Earth and of celestial bodies are governed by the same set of natural laws, which were neither capricious nor malevolent. By demonstrating the consistency between Kepler's laws of planetary motion and his own theory of gravitation, Newton also removed the last doubts about heliocentrism. By bringing together all the ideas set forth during the Scientific revolution, Newton effectively established the foundation for modern society in mathematics and science.

text: Newton built the first functioning

entity_name: Reflecting telescope

text: reflecting telescope

text: and developed a theory of color, published in

entity_name: Opticks

text: Opticks

text: , based on the observation that a

entity_name: Dispersive prism

text: prism

text: decomposes

entity_section: Visible radiation (light)

text: white light

text: into the many colours forming the

entity_name: Visible spectrum

text: visible spectrum

text: . While Newton explained light as being composed of tiny particles, a rival theory of light which explained its behavior in terms of waves was presented in 1690 by

entity_name: Christiaan Huygens

text: Christiaan Huygens

text: . However, the belief in the mechanistic philosophy coupled with Newton's reputation meant that the wave theory saw relatively little support until the 19th century. Newton also formulated

entity_name: Newton's law of cooling

text: an empirical law of cooling

text: , studied the

entity_name: Speed of sound

text: speed of sound

text: , investigated

entity_name: Power series

text: power series

text: , demonstrated the

entity_name: Binomial theorem

text: generalised binomial theorem

text: and developed

entity_name: Newton's method

text: a method

text: for approximating the

entity_name: Zero of a function

text: roots of a function

text: . His work on infinite series was inspired by

entity_name: Simon Stevin

text: Simon Stevin

text: 's decimals. Most importantly, Newton showed that the motions of objects on Earth and of celestial bodies are governed by the same set of natural laws, which were neither capricious nor malevolent. By demonstrating the consistency between

entity_name: Kepler's laws of planetary motion

text: Kepler's laws of planetary motion

text: and his own theory of gravitation, Newton also removed the last doubts about heliocentrism. By bringing together all the ideas set forth during the Scientific revolution, Newton effectively established the foundation for modern society in mathematics and science.

text: Recently, reel-less gear has been adopted for all weapons at top competitions. In this system, which dispenses with the spool (by using the fencer's own body as a grounding point), the lights and detectors are mounted directly on the fencers' masks. For the sake of the audience, clearly visible peripheral lights triggered by wireless transmission may be used. However, the mask lights must remain as the official indicators because FIE regulations prohibit the use of wireless transmitters in official scoring equipment in order to prevent cheating. The development of reel-less scoring apparatus in épée and foil has been much slower due to technical complications. The first international competitions to use the reel-less versions of these weapons were held in 2006.

text: Colour-producing molecules fall into two distinct classes: biochromes and structural colours or "schemochromes". The biochromes include true pigments, such as carotenoids and pteridines. These pigments selectively absorb parts of the visible light spectrum that makes up white light while permitting other wavelengths to reach  the eye of the observer. Structural colours are produced by various combinations of diffraction, reflection or scattering of light from structures with a scale around a quarter of the wavelength of light. Many such structures interfere with some wavelengths (colours) of light and transmit others, simply because of their scale, so they often produce iridescence, creating different colours when seen from different directions.

text: Colour-producing molecules fall into two distinct classes:

entity_name: Biological pigment

text: biochromes

text: and

entity_name: Structural coloration

text: structural colours

text: or "schemochromes". The biochromes include true pigments, such as

entity_name: Carotenoid

text: carotenoid

text: s and

entity_name: Pteridine

text: pteridine

text: s. These pigments selectively absorb parts of the

text: visible light spectrum

text: that makes up white light while permitting other

text: wavelength

text: s to reach  the eye of the observer. Structural colours are produced by various combinations of diffraction, reflection or scattering of light from structures with a scale around a quarter of the wavelength of light. Many such structures interfere with some wavelengths (colours) of light and transmit others, simply because of their scale, so they often produce

entity_name: Iridescence

text: iridescence

text: , creating different colours when seen from different directions.

text: Modern automatic transmissions can trace their origins to an early "horseless carriage" gearbox that was developed in 1904 by the Sturtevant brothers of Boston, Massachusetts. This unit had two forward speeds, the ratio change being brought about by flyweights that were driven by the engine. At higher engine speeds, high gear was engaged. As the vehicle slowed down and engine RPM decreased, the gearbox would shift back to low. Unfortunately, the metallurgy of the time wasn't up to the task, and owing to the abruptness of the gear change, the transmission would often fail without warning.

text: Modern automatic transmissions can trace their origins to an early "

entity_name: Horseless carriage

text: horseless carriage

text: " gearbox that was developed in 1904 by the Sturtevant brothers of

entity_name: Boston

text: Boston

entity_name: Massachusetts

text: Massachusetts

text: . This unit had two forward speeds, the ratio change being brought about by flyweights that were driven by the engine. At higher engine speeds, high gear was engaged. As the vehicle slowed down and engine RPM decreased, the gearbox would shift back to low. Unfortunately, the

entity_name: Metallurgy

text: metallurgy

text: of the time wasn't up to the task, and owing to the abruptness of the gear change, the transmission would often fail without warning.

text: Over a long period of time, the slightly denser regions of the nearly uniformly distributed matter gravitationally attracted nearby matter and thus grew even denser, forming gas clouds, stars, galaxies, and the other astronomical structures observable today. The details of this process depend on the amount and type of matter in the universe. The four possible types of matter are known as cold dark matter, warm dark matter, hot dark matter, and baryonic matter. The best measurements available (from WMAP) show that the data is well-fit by a Lambda-CDM model in which dark matter is assumed to be cold (warm dark matter is ruled out by early reionization), and is estimated to make up about 23% of the matter/energy of the universe, while baryonic matter makes up about 4.6%. In an "extended model" which includes hot dark matter in the form of neutrinos, then if the "physical baryon density" Ωh is estimated at about 0.023 (this is different from the 'baryon density' Ω expressed as a fraction of the total matter/energy density, which as noted above is about 0.046), and the corresponding cold dark matter density Ωh is about 0.11, the corresponding neutrino density Ωh is estimated to be less than 0.0062.

text: Over a long period of time, the slightly denser regions of the nearly uniformly distributed matter gravitationally attracted nearby matter and thus grew even denser, forming gas clouds, stars, galaxies, and the other astronomical structures observable today. The details of this process depend on the amount and type of matter in the universe. The four possible types of matter are known as

text: cold dark matter

text: warm dark matter

text: hot dark matter

text: , and

text: baryonic matter

text: . The best measurements available (from

text: WMAP

text: ) show that the data is well-fit by a Lambda-CDM model in which dark matter is assumed to be cold (warm dark matter is ruled out by early

text: reionization

text: ), and is estimated to make up about 23% of the matter/energy of the universe, while baryonic matter makes up about 4.6%. In an "extended model" which includes hot dark matter in the form of

text: neutrino

text: s, then if the "physical baryon density" Ωh is estimated at about 0.023 (this is different from the 'baryon density' Ω expressed as a fraction of the total matter/energy density, which as noted above is about 0.046), and the corresponding cold dark matter density Ωh is about 0.11, the corresponding neutrino density Ωh is estimated to be less than 0.0062.

text: Stevens' first point was that the Boy Scouts' ban on gay members did not follow from its founding principles. The Boy Scouts sought to instill "values" in young people, "to prepare them to make ethical choices over their lifetime in achieving their full potential." The Scout Oath and the Scout Law, which set forth the Scouts' central tenets, assist in this goal. One of these tenets is that a Scout is "morally straight." Another is that a Scout is "clean." As these terms were defined in the Scout Handbook, Stevens said, "it is plain as the light of day that neither one of these principles—'morally straight' and 'clean'—says the slightest thing about homosexuality. Indeed, neither term in the Boy Scouts' Law and Oath expresses any position whatsoever on sexual matters."

text: Thanks to the transmission of the Rugby World Cup, on 20 October 2003 was the first training of Lobo Bravo Rugby, the principle in the Plaza of Ukraine, which local, being public, has enough visibility of the sport practice.

text: Thanks to the transmission of the

text: Rugby World Cup

text: , on 20 October 2003 was the first training of Lobo Bravo Rugby, the principle in the Plaza of Ukraine, which local, being public, has enough visibility of the sport practice.

text: In photometry, luminous energy is the perceived energy of light. This is sometimes called the quantity of light. Luminous energy is not the same as radiant energy, the corresponding objective physical quantity. This is because the human eye can only see light in the visible spectrum and has different sensitivities to light of different wavelengths within the spectrum. When adapted for bright conditions (photopic vision), the eye is most sensitive to light at a wavelength of 555 nm. Light with a given amount of radiant energy will have more luminous energy if the wavelength is 555 nm than if the wavelength is longer or shorter. Light whose wavelength is well outside the visible spectrum has a luminous energy of zero, regardless of the amount of radiant energy present.

text: In

text: photometry

text: , luminous energy is the perceived

text: energy

text: of

text: light

text: . This is sometimes called the quantity of light. Luminous energy is not the same as

text: radiant energy

text: , the corresponding objective

text: physical quantity

text: . This is because the

text: human eye

text: can only see light in the

text: visible spectrum

text: and has different sensitivities to

text: light

text: of different

text: wavelength

text: s within the spectrum. When adapted for bright conditions (

text: photopic vision

text: ), the eye is most sensitive to light at a wavelength of 555

text: nm

text: . Light with a given amount of radiant energy will have more luminous energy if the wavelength is 555 nm than if the wavelength is longer or shorter. Light whose wavelength is well outside the

text: visible spectrum

text: has a luminous energy of zero, regardless of the amount of radiant energy present.

text: By manipulating imagery data values and positions, it is possible to see features that would not normally be visible and to locate geo-positions of features that would otherwise be graphical. The level of brightness, or reflectance of light from the surfaces in the image can be helpful with vegetation analysis, prospecting for minerals etc. Other usage examples include linear feature extraction, generation of processing work flows (spatial models in Imagine), import/export of data for a wide variety of formats, orthorectification, mosaicking of imagery, stereo and automatic feature extraction of map data from imagery.

text: By manipulating imagery data values and positions, it is possible to see features that would not normally be visible and to locate geo-positions of features that would otherwise be graphical. The level of brightness, or reflectance of light from the surfaces in the image can be helpful with vegetation analysis, prospecting for minerals etc. Other usage examples include linear feature extraction, generation of processing work flows (spatial models in Imagine), import/export of data for a wide variety of formats,

text: orthorectification

text: , mosaicking of imagery, stereo and automatic feature extraction of map data from imagery.

text: Dielectric loss and non-zero DC conductivity in materials cause absorption. Good dielectric materials such as glass have extremely low DC conductivity, and at low frequencies the dielectric loss is also negligible, resulting in almost no absorption. However, at higher frequencies (such as visible light), dielectric loss may increase absorption significantly, reducing the material's transparency to these frequencies.

text: Dielectric loss and non-zero DC conductivity in materials cause absorption. Good dielectric materials such as glass have extremely low DC conductivity, and at low frequencies the dielectric loss is also negligible, resulting in almost no absorption. However, at higher frequencies (such as visible light), dielectric loss may increase absorption significantly, reducing the material's

text: transparency

text: to these frequencies.

text: Light behaves in some respects like particles and in other respects like waves. Matter—particles such as electrons and atoms—exhibits wavelike behaviour too. Some light sources, including neon lights, give off only certain frequencies of light. Quantum mechanics shows that light, along with all other forms of electromagnetic radiation, comes in discrete units, called photons, and predicts its energies, colours, and spectral intensities. Since one never observes half a photon, a single photon is a quantum, or smallest observable amount, of the electromagnetic field. More broadly, quantum mechanics shows that many quantities, such as angular momentum, that appeared to be continuous in the zoomed-out view of classical mechanics, turn out to be (at the small, zoomed-in scale of quantum mechanics) quantized. Angular momentum is required to take on one of a set of discrete allowable values, and since the gap between these values is so minute, the discontinuity is only apparent at the atomic level.

text: Light behaves in some respects like particles and in other respects like waves. Matter—particles such as

text: electron

text: s and

text: atom

text: s—exhibits

text: wavelike behaviour

text: too. Some light sources, including

text: neon lights

text: , give off only certain frequencies of light. Quantum mechanics shows that light, along with all other forms of

text: electromagnetic radiation

text: , comes in discrete units, called

text: photon

text: s, and predicts its energies, colours, and

text: spectral

text: intensities

text: . Since one never observes half a photon, a single photon is a

text: quantum

text: , or smallest observable amount, of the electromagnetic field. More broadly, quantum mechanics shows that many quantities, such as

text: angular momentum

text: , that appeared to be continuous in the zoomed-out view of classical mechanics, turn out to be (at the small, zoomed-in scale of quantum mechanics) quantized. Angular momentum is required to take on one of a set of discrete allowable values, and since the gap between these values is so minute, the discontinuity is only apparent at the atomic level.

text: The watch had a small lens at the top of its face used for data transmission by visible light. Data was transmitted from the CRT of the computer through a series of pulsating horizontal bars, that were focused by the lens and written to the watch EEPROM memory through an optoelectronic transducer operating in the visible light spectrum and employing optical scanning technology.

text: The watch had a small

text: lens

text: at the top of its face used for

text: data transmission

text: by visible light. Data was transmitted from the

text: CRT

text: of the computer through a series of

text: pulsating

text: horizontal bars, that were focused by the lens and written to the watch

text: EEPROM

text: memory

text: through an

text: optoelectronic

text: transducer

text: operating in the

text: visible light

text: spectrum

text: and employing

text: optical scanning

text: technology.

text: Consider a reflection which appears to us in a mirror.  There is nothing corresponding to the reflection in the world external to the mind (for our reflection appears to us as the image of a human being apparently located inside a wall, or a wardrobe).  The appearance is therefore a mental object, a sense datum.

text: Neodymium is typically 10–18% of the rare earth content of commercial deposits of the light rare earth element minerals bastnäsite and monazite. With neodymium compounds being the most strongly colored for the trivalent lanthanides, that percentage of neodymium can occasionally dominate the coloration of rare earth minerals—when competing chromophores are absent. It usually gives a pink coloration. Outstanding examples of this include monazite crystals from the tin deposits in Llallagua, Bolivia; ancylite from Mont Saint-Hilaire, Quebec, Canada; or lanthanite from the Saucon Valley, Pennsylvania, United States. As with neodymium glasses, such minerals change their colors under the differing lighting conditions. The absorption bands of neodymium interact with the visible emission spectrum of mercury vapor, with the unfiltered shortwave UV light causing neodymium-containing minerals to reflect a distinctive green color. This can be observed with monazite-containing sands or bastnäsite-containing ore.

text: Neodymium is typically 10–18% of the rare earth content of commercial deposits of the light rare earth element minerals bastnäsite and monazite. With neodymium compounds being the most strongly colored for the trivalent lanthanides, that percentage of neodymium can occasionally dominate the coloration of rare earth minerals—when competing chromophores are absent. It usually gives a pink coloration. Outstanding examples of this include monazite crystals from the

text: tin

text: deposits in

text: Llallagua

text: Bolivia

text: ancylite

text: from

text: Mont Saint-Hilaire

text: Quebec

text: Canada

text: ; or

text: lanthanite

text: from the

entity_name: Lower Saucon Township, Northampton County, Pennsylvania

text: Saucon Valley

text: Pennsylvania

text: , United States. As with neodymium glasses, such minerals change their colors under the differing lighting conditions. The absorption bands of neodymium interact with the visible

text: emission spectrum

text: of

text: mercury vapor

text: , with the unfiltered shortwave UV light causing neodymium-containing minerals to reflect a distinctive green color. This can be observed with monazite-containing sands or bastnäsite-containing ore.

text: The theory of light-matter interaction on which Cauchy based this equation was later found to be incorrect. In particular, the equation is only valid for regions of normal dispersion in the visible wavelength region. In the infrared, the equation becomes inaccurate, and it cannot represent regions of anomalous dispersion. Despite this, its mathematical simplicity makes it useful in some applications.

text: The theory of light-matter interaction on which Cauchy based this equation was later found to be incorrect. In particular, the equation is only valid for regions of normal

text: dispersion

text: in the

text: visible wavelength

text: region. In the

text: infrared

text: , the equation becomes inaccurate, and it cannot represent regions of anomalous dispersion. Despite this, its mathematical simplicity makes it useful in some applications.

text: The optical properties of the lining of the sphere greatly affect its accuracy. Different coatings must be used at visible, infrared and ultraviolet wavelengths. High-powered illumination sources may heat or damage the coating, so an integrating sphere will be rated for a maximum level of incident power. Various coating materials are used.  For visible-spectrum light, early experimenters used a deposit of magnesium oxide,  and barium sulfate also has a usefully flat reflectance over the visible spectrum. Various proprietary PTFE compounds are also used for visible light measurements. Finely-deposited gold is used for infrared measurements.

text: The optical properties of the lining of the sphere greatly affect its accuracy. Different coatings must be used at visible, infrared and ultraviolet wavelengths. High-powered illumination sources may heat or damage the coating, so an integrating sphere will be rated for a maximum level of incident power. Various coating materials are used.  For visible-spectrum light, early experimenters used a deposit of

text: magnesium oxide

text: ,  and

text: barium sulfate

text: also has a usefully flat reflectance over the visible spectrum. Various proprietary

text: PTFE

text: compounds are also used for visible light measurements. Finely-deposited gold is used for infrared measurements.

text: The transverse lattice method brings together two powerful ideas in quantum field theory: light-front Hamiltonian quantization and lattice gauge theory. Lattice gauge theory is a very popular means of regulating for calculation the gauge theories that describe all visible matter in the universe; in particular, it manifestly demonstrates the linear confinement of QCD that holds quarks and gluons inside the protons and neutrons of the atomic nucleus. In general, to obtain solutions of a quantum field theory, with its continuously infinite degrees of freedom, one must put kinematical cutoffs or other restrictions on the space of quantum states. To remove the errors this introduces, one may then extrapolate these cutoffs, provided a continuum limit exists, and/or renormalize observables to account for degrees of freedom above the cutoff. For the purposes of Hamiltonian quantization, one must have a continuous time direction. In the case of light-front Hamiltonian quantization, in addition to continuous light-front time

text: The transverse lattice method brings together two powerful ideas in quantum field theory: light-front Hamiltonian quantization and lattice gauge theory. Lattice gauge theory is a very popular means of regulating for calculation the gauge theories that describe all visible matter in the universe; in particular, it manifestly demonstrates the linear

text: confinement

text: of QCD that holds quarks and gluons inside the protons and neutrons of the atomic nucleus. In general, to obtain solutions of a quantum field theory, with its continuously infinite degrees of freedom, one must put kinematical cutoffs or other restrictions on the space of quantum states. To remove the errors this introduces, one may then extrapolate these cutoffs, provided a continuum limit exists, and/or renormalize observables to account for degrees of freedom above the cutoff. For the purposes of Hamiltonian quantization, one must have a continuous time direction. In the case of light-front Hamiltonian quantization, in addition to continuous light-front time

text: Photoluminescence is  light resulting from absorption of photons.

text: Photochemistry is the branch of chemistry concerned with the chemical effects of light. Generally, this term is used to describe a chemical reaction caused by absorption of ultraviolet (wavelength from 100 to 400 nm), visible light (400 – 750 nm) or infrared radiation (750 – 2500 nm).

text: Photochemistry is the branch of

text: chemistry

text: concerned with the chemical effects of light. Generally, this term is used to describe a chemical reaction caused by absorption of

text: ultraviolet

text: wavelength

text: from 100 to 400

text: nm

text: visible light

text: (400 – 750 nm) or

text: infrared

text: radiation (750 – 2500 nm).

text: As the galactic plane does not pass through this part of Serpens, a view to many galaxies beyond it is possible. However, a few structures of the Milky Way Galaxy are present in Serpens Caput, such as Messier 5, a globular cluster positioned approximately 8° southwest of α Serpentis, next to the star 5 Serpentis. Barely visible to the naked eye under good conditions, and is located approximately 25,000 ly distant. Messier 5 contains a large number of known RR Lyrae variable stars, and is receding from us at over 50 km/s. The cluster contains two millisecond pulsars, one of which is in a binary, allowing the proper motion of the cluster to be measured. The binary could help our understanding of neutron degenerate matter; the current median mass, if confirmed, would exclude any "soft" equation of state for such matter. The cluster has been used to test for magnetic dipole moments in neutrinos, which could shed light on some hypothetical particles such as the axion. Another globular cluster is Palomar 5, found just south of Messier 5. Many stars are leaving this globular cluster due to the Milky Way's gravity, forming a tidal tail over 30000 light-years long.

text: As the galactic plane does not pass through this part of Serpens, a view to many galaxies beyond it is possible. However, a few structures of the Milky Way Galaxy are present in Serpens Caput, such as

text: Messier 5

text: , a

text: globular cluster

text: positioned approximately 8° southwest of α Serpentis, next to the star

text: 5 Serpentis

text: . Barely visible to the naked eye under good conditions, and is located approximately 25,000 ly distant. Messier 5 contains a large number of known RR Lyrae variable stars, and is receding from us at over 50 km/s. The cluster contains two

text: millisecond pulsar

text: s, one of which is in a binary, allowing the

text: proper motion

text: of the cluster to be measured. The binary could help our understanding of

text: neutron degenerate matter

text: ; the current median mass, if confirmed, would exclude any "soft"

text: equation of state

text: for such matter. The cluster has been used to test for

text: magnetic dipole moment

text: s in neutrinos, which could shed light on some hypothetical particles such as the

text: axion

text: . Another globular cluster is

text: Palomar 5

text: , found just south of Messier 5. Many stars are leaving this globular cluster due to the Milky Way's gravity, forming a

text: tidal tail

text: over 30000 light-years long.

text: The Transmission of the Light gives 28 patriarchs in this transmission, and 53 overall:

text: The

text: Transmission of the Light

text: gives 28 patriarchs in this transmission, and 53 overall:

text: Planets are extremely faint light sources compared to stars, and what little light comes from them tends to be lost in the glare from their parent star. So in general, it is very difficult to detect and resolve them directly from their host star. Planets orbiting far enough from stars to be resolved reflect very little starlight, so planets are detected through their thermal emission instead. It is easier to obtain images when the star system is relatively near to the Sun, and when the planet is especially large (considerably larger than Jupiter), widely separated from its parent star, and hot so that it emits intense infrared radiation; images have then been made in the infrared, where the planet is brighter than it is at visible wavelengths. Coronagraphs are used to block light from the star, while leaving the planet visible. Direct imaging of an Earth-like exoplanet requires extreme optothermal stability. During the accretion phase of planetary formation, the star-planet contrast may be even better in H alpha than it is in infrared – an H alpha survey is currently underway.

text: Planets are extremely faint light sources compared to stars, and what little light comes from them tends to be lost in the glare from their parent star. So in general, it is very difficult to detect and resolve them directly from their host star. Planets orbiting far enough from stars to be resolved reflect very little starlight, so planets are detected through their thermal emission instead. It is easier to obtain images when the star system is relatively near to the Sun, and when the planet is especially large (considerably larger than

text: Jupiter

text: ), widely separated from its parent star, and hot so that it emits intense infrared radiation; images have then been made in the infrared, where the planet is brighter than it is at visible wavelengths.

text: Coronagraph

text: s are used to block light from the star, while leaving the planet visible. Direct imaging of an Earth-like exoplanet requires extreme

text: optothermal stability

text: . During the accretion phase of planetary formation, the star-planet contrast may be even better in

text: H alpha

text: than it is in infrared – an H alpha survey is currently underway.

text: If a single photon approaches an atom which is receptive to it, the photon can be absorbed by the atom in a manner very similar to a radio wave being picked up by an aerial. At the moment of absorption the photon ceases to exist and the total energy contained within the atom increases. This increase in energy is usually described symbolically by saying that one of the outermost electrons "jumps" to a "higher orbit". This new atomic configuration is unstable and the tendency is for the electron to fall back to its lower orbit or energy level, emitting a new photon as it goes. The entire process may take no more than 1 x 10 seconds. The result is much the same as with reflective colour, but because of the process of absorption and emission, the substance emits a glow. According to Planck, the energy of each photon is given by multiplying its frequency in cycles per second by a constant (Planck’s constant, 6.626 x 10 erg seconds). It follows that the wavelength of a photon emitted from a luminescent system is directly related to the difference between the energy of the two atomic levels involved.

text: If a single

text: photon

text: approaches an

text: atom

text: which is receptive to it, the photon can be absorbed by the atom in a manner very similar to a

text: radio wave

text: being picked up by an aerial. At the moment of absorption the photon ceases to exist and the total energy contained within the atom increases. This increase in energy is usually described symbolically by saying that one of the outermost electrons "jumps" to a "higher orbit". This new atomic configuration is unstable and the tendency is for the electron to fall back to its lower orbit or energy level, emitting a new

text: photon

text: as it goes. The entire process may take no more than 1 x 10 seconds. The result is much the same as with reflective colour, but because of the process of absorption and emission, the substance emits a glow. According to

text: Planck

text: , the energy of each photon is given by multiplying its frequency in cycles per second by a constant (Planck’s constant, 6.626 x 10 erg seconds). It follows that the wavelength of a photon emitted from a luminescent system is directly related to the difference between the energy of the two atomic levels involved.

text: Two other topics that must be considered include the optics used to direct the radiation and the means of holding or containing the sample material (called a cuvette or cell). For most UV, visible, and NIR measurements the use of precision quartz cuvettes is necessary. In both cases, it is important to select materials that have relatively little absorption in the wavelength range of interest. Quartz is ideal because it transmits from 200 nm-2500 nm; higher grade quartz can even transmit up to 3500 nm, whereas the absorption properties of other materials can mask the fluorescence from the sample.

text: Optics and photonics are defined as the fields of science and engineering encompassing the physical phenomena and technologies associated with the generation, transmission, manipulation, detection, and utilisation of light. It extends on both sides of the visible part of the electromagnetic spectrum as far as the same concepts apply.

text: Optics

text: and

text: photonics

text: are defined as the fields of science and engineering encompassing the physical phenomena and technologies associated with the generation, transmission, manipulation, detection, and utilisation of light. It extends on both sides of the visible part of the electromagnetic spectrum as far as the same concepts apply.

text: Soot is composed of a complex mixture of organic compounds which are weakly absorbing in the visible spectral region and a highly absorbing black component which is variously called “elemental”, “graphitic” or “black carbon”. The term elemental carbon has been used in conjunction with thermal and wet chemical determinations and the term  graphitic carbon suggests the presence  of graphite-like micro-crystalline structures in soot as evidenced by Raman Spectroscopy.  The term black carbon is used to imply that this soot component is primarily responsible for the absorption of visible light.  The term black carbon is used as a synonym for both the elemental and graphitic component of soot. It can be measured using different types of devices based on absorption or dispersion of a light beam or derived from noise measurements.

text: Soot is composed of a complex mixture of organic compounds which are weakly absorbing in the visible spectral region and a highly absorbing black component which is variously called “elemental”, “graphitic” or “black carbon”. The term elemental carbon has been used in conjunction with thermal and wet chemical determinations and the term  graphitic carbon suggests the presence  of

text: graphite

text: -like micro-crystalline structures in soot as evidenced by

text: Raman Spectroscopy

text: .  The term black carbon is used to imply that this soot component is primarily responsible for the absorption of visible light.  The term black carbon is used as a synonym for both the elemental and graphitic component of soot. It can be measured using different types of devices based on absorption or dispersion of a light beam or derived from noise measurements.

text: The first optical answer sheets were read by shining a light through the sheet and measuring how much of the light was blocked using phototubes on the opposite side. As some phototubes are mostly sensitive to the blue end of the visible spectrum, blue pens could not be used, as blue inks reflect and transmit blue light. Because of this, number two pencils had to be used to fill in the bubbles—graphite is a very opaque substance which absorbs or reflects most of the light which hits it.

text: The first optical answer sheets were read by shining a light through the sheet and measuring how much of the light was blocked using

text: phototubes

text: on the opposite side. As some phototubes are mostly sensitive to the blue end of the

text: visible spectrum

text: , blue pens could not be used, as blue inks reflect and

text: transmit

text: blue light. Because of this,

text: number two pencils

text: had to be used to fill in the bubbles—

text: graphite

text: is a very

text: opaque

text: substance which absorbs or reflects most of the light which hits it.

text: Infrared light lies between the visible and microwave portions of the electromagnetic spectrum. Infrared light has a range of wavelengths, just like visible light has wavelengths that range from red light to violet. "Near infrared" light is closest in wavelength to visible light and "far infrared" is closer to the microwave region of the electromagnetic spectrum. The longer, far infrared wavelengths are about the size of a pin head and the shorter, near infrared ones are the size of cells, or are microscopic.

text: Infrared light lies between the visible and microwave portions of the

text: electromagnetic spectrum

text: . Infrared light has a range of wavelengths, just like visible light has wavelengths that range from red light to violet. "Near infrared" light is closest in wavelength to visible light and "far infrared" is closer to the microwave region of the electromagnetic spectrum. The longer, far infrared wavelengths are about the size of a pin head and the shorter, near infrared ones are the size of cells, or are microscopic.

text: Because of the faintness of the lowest luminosity dwarf spheroidals and the nature of the stars contained within them, some astronomers suggest that dwarf spheroidals and globular clusters may not be clearly separate and distinct types of objects. Other recent studies, however, have found a distinction in that the total amount of mass inferred from the motions of stars in dwarf spheroidals is many times that which can be accounted for by the mass of the stars themselves.  In the current predominantly accepted Lambda cold dark matter cosmological model, this is seen as a sure sign of dark matter, and the presence of dark matter is often cited as a reason to classify dwarf spheroidals as a different class of object from globular clusters (which show little to no signs of dark matter).  Because of the extremely large amounts of dark matter in these objects, they may deserve the title "most dark matter-dominated galaxies"

text: Because of the faintness of the lowest luminosity dwarf spheroidals and the nature of the stars contained within them, some astronomers suggest that dwarf spheroidals and

text: globular cluster

text: s may not be clearly separate and distinct types of objects. Other recent studies, however, have found a distinction in that the total amount of mass inferred from the motions of stars in dwarf spheroidals is many times that which can be accounted for by the mass of the stars themselves.  In the current predominantly accepted

text: Lambda cold dark matter

text: cosmological model, this is seen as a sure sign of

text: dark matter

text: , and the presence of dark matter is often cited as a reason to classify dwarf spheroidals as a different class of object from globular clusters (which show little to no signs of dark matter).  Because of the extremely large amounts of dark matter in these objects, they may deserve the title "most dark matter-dominated galaxies"

text: In nature, a light source emits a ray of light which travels, eventually, to a surface that interrupts its progress.  One can think of this "ray" as a stream of photons traveling along the same path.  In a perfect vacuum this ray will be a straight line (ignoring relativistic effects). Any combination of four things might happen with this light ray:  absorption, reflection, refraction and fluorescence.  A surface may absorb part of the light ray, resulting in a loss of intensity of the reflected and/or refracted light.  It might also reflect all or part of the light ray, in one or more directions. If the surface has any transparent or translucent properties, it refracts a portion of the light beam into itself in a different direction while absorbing some (or all) of the spectrum (and possibly altering the color). Less commonly, a surface may absorb some portion of the light and fluorescently re-emit the light at a longer wavelength color in a random direction, though this is rare enough that it can be discounted from most rendering applications. Between absorption, reflection, refraction and fluorescence, all of the incoming light must be accounted for, and no more.  A surface cannot, for instance, reflect 66% of an incoming light ray, and refract 50%, since the two would add up to be 116%. From here, the reflected and/or refracted rays may strike other surfaces, where their absorptive, refractive, reflective and fluorescent properties again affect the progress of  the incoming rays.  Some of these rays travel in such a way that they hit our eye, causing us to see the scene and so contribute to the final rendered image.

text: In nature, a light source emits a ray of light which travels, eventually, to a surface that interrupts its progress.  One can think of this "ray" as a stream of

text: photon

text: s traveling along the same path.  In a perfect vacuum this ray will be a straight line (ignoring

text: relativistic effects

text: ). Any combination of four things might happen with this light ray:

text: absorption

text: reflection

text: refraction

text: and

text: fluorescence

text: .  A surface may absorb part of the light ray, resulting in a loss of intensity of the reflected and/or refracted light.  It might also reflect all or part of the light ray, in one or more directions. If the surface has any

text: transparent

text: or

text: translucent

text: properties, it refracts a portion of the light beam into itself in a different direction while absorbing some (or all) of the

text: spectrum

text: (and possibly altering the color). Less commonly, a surface may absorb some portion of the light and fluorescently re-emit the light at a longer wavelength color in a random direction, though this is rare enough that it can be discounted from most rendering applications. Between absorption, reflection, refraction and fluorescence, all of the incoming light must be accounted for, and no more.  A surface cannot, for instance, reflect 66% of an incoming light ray, and refract 50%, since the two would add up to be 116%. From here, the reflected and/or refracted rays may strike other surfaces, where their absorptive, refractive, reflective and fluorescent properties again affect the progress of  the incoming rays.  Some of these rays travel in such a way that they hit our eye, causing us to see the scene and so contribute to the final rendered image.

text: The term "reflection" is loose, and considered by some an abuse of language, with "inversion" preferred; however, "point reflection" is widely used. Such maps are involutions, meaning that they have order 2 – they are their own inverse: applying them twice yields the identity map – which is also true of other maps called "reflections". More narrowly, a "reflection" refers to a reflection in a hyperplane (

text: The term "reflection" is loose, and considered by some an abuse of language, with "inversion" preferred; however, "point reflection" is widely used. Such maps are

text: involution

text: s, meaning that they have order 2 – they are their own inverse: applying them twice yields the

text: identity map

text: – which is also true of other maps called "reflections". More narrowly, a "

text: reflection

text: " refers to a reflection in a

text: hyperplane

text: Since the 1980s, Brigitte Kowanz's work has focused on the investigation of space and light. At the beginning of this period, between 1979 and 1984, she produced paper and screen images with phosphorescent and fluorescent pigments in collaboration with Franz Graf. From 1984, Kowanz developed her first light objects from bottles, fluorescent lamps and fluorescent paint. Complex spatial images and light-shadow-projections were created using the simplest of means.However, light is not only a material, but also often a topic of Kowanz's works. For example, she has been engaged with the speed of light in a personal complex of works since 1989. A very small decimal number in neon figures indicates the time that the light needs to cover the length of this sequence of numbers.One complex of issues that Kowanz has also been engaged in since the 1980s is that of language and writing and its translation into codes. Light is investigated as a space-forming medium as well as an information carrier and medium of knowledge and visibility.Since 1995, Kowanz has also regularly used the morse alphabet – based on simple dash-dot combinations – for coding purposes. As a binary code, it represents the origin of the transfer of information using light. Kowanz uses (semi-)transparent glasses and mirrors, especially in her newer works. This leads to a diverse overlaying of the virtual and the real in her three-dimensional objects. The mutual reflection of light, language and mirror (Rainer Fuchs) produces hybrid spaces whose boundaries seem to be clearly defined at one moment, but gone again the next. Real space and virtual reflection penetrate each other, the boundaries between artwork and observer become fluid.The occupation with the intangible physics of light, which – although a guarantee of visibility – is itself slightly overlooked, persists in the works of Brigitte Kowanz to this day.

text: Since the 1980s, Brigitte Kowanz's work has focused on the investigation of

text: space

text: and light. At the beginning of this period, between 1979 and 1984, she produced paper and screen images with

text: phosphorescent

text: and

text: fluorescent

text: pigments in collaboration with

text: Franz Graf

text: . From 1984, Kowanz developed her first light objects from bottles,

text: fluorescent lamp

text: s and fluorescent paint. Complex spatial images and light-shadow-projections were created using the simplest of means.However, light is not only a material, but also often a topic of Kowanz's works. For example, she has been engaged with the

text: speed of light

text: in a personal complex of works since 1989. A very small decimal number in neon figures indicates the time that the light needs to cover the length of this sequence of numbers.One complex of issues that Kowanz has also been engaged in since the 1980s is that of

text: language

text: and writing and its translation into

text: code

text: s. Light is investigated as a space-forming medium as well as an information carrier and medium of knowledge and visibility.Since 1995, Kowanz has also regularly used the

text: morse alphabet

text: – based on simple dash-dot combinations – for coding purposes. As a binary code, it represents the origin of the transfer of information using light. Kowanz uses (semi-)transparent glasses and

text: mirror

text: s, especially in her newer works. This leads to a diverse overlaying of the virtual and the real in her three-dimensional objects. The mutual reflection of light, language and mirror (Rainer Fuchs) produces hybrid spaces whose boundaries seem to be clearly defined at one moment, but gone again the next. Real space and virtual reflection penetrate each other, the boundaries between artwork and observer become fluid.The occupation with the intangible physics of light, which – although a guarantee of visibility – is itself slightly overlooked, persists in the works of Brigitte Kowanz to this day.

text: Another environmental effect is range of visibility. The water is seldom optimally clear, and the dissolved and suspended matter can reduce visibility by both absorption and scattering of light.

text: For most materials at visible-light frequencies, the phase is somewhere between 90° and 180°, corresponding to a combination of both refraction and absorption.

text: Operetta (literally "little opera") is a genre of light opera – light in terms of the subject matter and light in terms of the music itself. Operetta also shares many characteristics with musical theatre. The following is a list of composers who have written works in this genre:

text: Operetta (literally "little opera") is a

text: genre

text: of light

text: opera

text: – light in terms of the subject matter and light in terms of the music itself. Operetta also shares many characteristics with

text: musical theatre

text: . The following is a list of composers who have written works in this genre:

text: For example, a photon is a single quantum of (visible) light as well as a single quantum of any other form of electromagnetic radiation, and can be referred to as a "light quantum".  The energy of an electron bound to an atom is also quantized, and thus can only exist in certain discrete values. As a result, atoms are stable, and hence matter in general is stable.

text: For example, a photon is a single quantum of (visible)

text: light

text: as well as a single quantum of any other form of

text: electromagnetic radiation

text: , and can be referred to as a "light quantum".  The energy of an

text: electron

text: bound to an

text: atom

text: is also quantized, and thus can only exist in certain discrete values. As a result, atoms are stable, and hence matter in general is stable.

text: Light is made up of particles called photons and hence inherently is quantized.  Quantum optics is the study of the nature and effects of light as quantized photons. The first indication that light might be quantized came from Max Planck in 1899 when he correctly modelled blackbody radiation by assuming that the exchange of energy between light and matter only occurred in discrete amounts he called quanta. It was unknown whether the source of this discreteness was the matter or the light. In 1905, Albert Einstein published the theory of the photoelectric effect. It appeared that the only possible explanation for the effect was the quantization of light itself. Later, Niels Bohr showed that atoms could only emit discrete amounts of energy. The understanding of the interaction between light and matter following from these developments not only formed the basis of quantum optics but also were crucial for the development of quantum mechanics as a whole. However, the subfields of quantum mechanics dealing with matter-light interaction were principally regarded as research into matter rather than into light and hence, one rather spoke of atom physics and quantum electronics.

text: Light is made up of particles called

text: photons

text: and hence inherently is quantized.  Quantum optics is the study of the nature and effects of light as quantized photons. The first indication that light might be quantized came from

text: Max Planck

text: in 1899 when he correctly modelled

text: blackbody radiation

text: by assuming that the exchange of energy between light and matter only occurred in discrete amounts he called quanta. It was unknown whether the source of this discreteness was the matter or the light. In 1905,

text: Albert Einstein

text: published the theory of the

text: photoelectric effect

text: . It appeared that the only possible explanation for the effect was the quantization of light itself. Later,

text: Niels Bohr

text: showed that atoms could only emit discrete amounts of energy. The understanding of the interaction between light and

text: matter

text: following from these developments not only formed the basis of quantum optics but also were crucial for the development of quantum mechanics as a whole. However, the subfields of quantum mechanics dealing with matter-light interaction were principally regarded as research into matter rather than into light and hence, one rather spoke of

text: atom physics

text: and

text: quantum electronics

text: There is considerable speculation as to why the observable universe is composed almost entirely of ordinary matter, as opposed to an even mixture of matter and antimatter. This asymmetry of matter and antimatter in the visible universe is one of the great unsolved problems in physics. The process by which this inequality between particles and antiparticles developed is called baryogenesis.

text: There is considerable speculation as to why the

text: observable universe

text: is composed almost entirely of ordinary matter, as opposed to an even mixture of matter and antimatter. This

text: asymmetry of matter and antimatter

text: in the

text: visible universe

text: is one of the great

text: unsolved problems in physics

text: . The process by which this inequality between particles and antiparticles developed is called

text: baryogenesis

text: Gray Matters Capital's history includes starting Gray Ghost Ventures, the Short Term Liquidity Fund, Gray Ghost Microfinance Fund, GGV Doen Cooperatief, First Light Ventures, Gray Matters India - School Rating System, Gray Matters Kenya, IDEX Accelerator Fellowship, and Village Capital.

text: Gray Matters Capital's history includes starting

text: Gray Ghost Ventures

text: , the Short Term Liquidity Fund, Gray Ghost Microfinance Fund, GGV Doen Cooperatief, First Light Ventures, Gray Matters India - School Rating System, Gray Matters Kenya, IDEX Accelerator Fellowship, and

text: Village Capital

text: The launch model was the 528e in 1982, followed by the 533i. The optional automatic transmission was initially a 3-speed (a 4-speed automatic was available in Europe at the time), with a 4-speed automatic transmission becoming optional in 1983. The 524td was only imported with an automatic transmission, and the M5 was only imported with a manual transmission. From 1985, all North American models had ABS Brakes as standard. Electric front seats became a standard feature in 1986.North American specification cars were comprehensively equipped, with standard features including power windows, central locking, air conditioning, power sunroof, cruise control, alloy wheels and fog lights.

text: In physics, absorption of electromagnetic radiation is the way by which the energy of a photon is taken up by matter, typically the electrons of an atom. Thus, the electromagnetic energy is transformed to other forms of energy, for example, to heat. The absorption of light during wave propagation is often called attenuation. Usually, the absorption of waves does not depend on their intensity (linear absorption), although in certain conditions (usually, in optics), the medium changes its transparency dependently on the intensity of waves going through, and the Saturable absorption (or nonlinear absorption) occurs.

text: In

text: physics

text: absorption

text: of electromagnetic radiation is the way by which the

text: energy

text: of a

text: photon

text: is taken up by matter, typically the electrons of an atom. Thus, the electromagnetic energy is transformed to other forms of energy, for example, to heat. The absorption of light during

text: wave propagation

text: is often called

text: attenuation

text: . Usually, the absorption of waves does not depend on their intensity (linear absorption), although in certain conditions (usually, in

text: optics

text: ), the medium changes its transparency dependently on the intensity of waves going through, and the

text: Saturable absorption

text: (or nonlinear absorption) occurs.

text: Considering light which is scattered only once in the atmosphere, the light received by the instrument at surface is contributed by light scattered downward from all the levels in the atmosphere. The amount of light contributed by scattering at any particular level depends on (a) the number of air molecules at that level and (b) the absorption by ozone and scattering by air moleculaes both before and after scattering. As the height increases contribution of effect (a) decreases and contribution of effect (b) increases. For a given zenith angle, the scattered light contribution comes from well defined layer of atmosphere, which can be termed as an effective scattering height. The effective scattering height depends on the ozone absorption coefficient and on the solar zenith angle, increasing as with each of these. The effective scattering height will always be higher for shorter wavelength which is more strongly absorbed. As the sun approaches the horizon, the two intensities decreases, but intensity I decreasing more rapidly than I' . However, when the effective scattering height for the short wavelength is above the ozone maximum, I decreases more slowly than I' , because the ozone absorption occurs mostly in the shorter vertical path after the scattering event, and the ratio I/I increases until the effective scattering height for I'  is also above the ozone maximum. This reversal (Umkehr) or inversion implies the existence of maximum of ozone concentration at some level in the atmosphere.

text: However, the dark star is capable of emitting indirect radiation – outward-aimed light and matter can leave the r = 2M surface briefly before being recaptured, and whilst outside the critical surface, can interact with other matter, or be accelerated free from the star through such interactions. A dark star therefore has a rarefied atmosphere of "visiting particles", and this ghostly halo of matter and light can radiate, albeit weakly.

text: Although there is much overlap in the requirements and use of instruments, ordinary CD instruments are usually optimized for operation in the ultraviolet, approximately 170–300 nm, while MCD instruments are typically required to operate in the visible to near infrared, approximately 300–2000 nm. The physical processes that lead to MCD are substantively different from those of CD. However, like CD, it is dependent on the differential absorption of left and right hand circularly polarized light. MCD will only exist at a given wavelength if the studied sample has an optical absorption at that wavelength. This is distinctly different from the related phenomenon of optical rotatory dispersion (ORD), which can be observed at wavelengths far from any absorption band.

text: Although there is much overlap in the requirements and use of instruments, ordinary CD instruments are usually optimized for operation in the

text: ultraviolet

text: , approximately 170–300

text: nm

text: , while MCD instruments are typically required to operate in the visible to

text: near infrared

text: , approximately 300–2000 nm. The physical processes that lead to MCD are substantively different from those of

text: CD

text: . However, like CD, it is dependent on the differential absorption of left and right hand circularly polarized light. MCD will only exist at a given wavelength if the studied sample has an

text: optical absorption

text: at that wavelength. This is distinctly different from the related phenomenon of

text: optical rotatory dispersion

text: (ORD), which can be observed at wavelengths far from any absorption band.

text: A visible light sensor (for example a camera: 0.4 to 0.7 µm) is able to present an image, which can be understood by a human being. Furthermore complex image processing analysis can be executed by computers, which can recognize a flame or even smoke. Unfortunately, a camera can be blinded, like a human, by heavy smoke and by fog. It is also possible to mix visible light information (monitor) with UV or Infrared information, which in this case is made visible. The corona camera is an example of this equipment. In this equipment the information of an UV camera mixed with visible image information. It is used for tracing defects in high voltage equipment and fire detection over high distances.

text: A visible light sensor (for example a camera: 0.4 to 0.7 µm) is able to present an image, which can be understood by a human being. Furthermore complex image processing analysis can be executed by computers, which can recognize a flame or even smoke. Unfortunately, a camera can be blinded, like a human, by heavy smoke and by fog. It is also possible to mix visible light information (monitor) with UV or

text: Infrared

text: information, which in this case is made visible. The corona

text: camera

text: is an example of this equipment. In this equipment the information of an UV camera mixed with visible image information. It is used for tracing defects in

text: high voltage

text: equipment and fire detection over high distances.

text: Glass may also be used as a protective layer to protect the other layers from abrasion and corrosion.  Although glass is brittle, it is a good material for this purpose, because it is highly transparent (low optical losses), resistant to ultraviolet light (UV), fairly hard (abrasion resistant), chemically inert, and fairly easy to clean.  It is composed of a float glass with high optical transmission characteristics in the visible and infrared ranges, and is configured to transmit visible light and infrared radiation.  The top surface, known as the "first surface", will reflect some of the incident solar energy, due to the reflection coefficient caused by its index of refraction being higher than air.  Most of the solar energy is transmitted through the glass substrate to the lower layers of the mirror, possibly with some refraction, depending on the angle of incidence as light enters the mirror.

text: Glass may also be used as a protective layer to protect the other layers from abrasion and corrosion.  Although glass is brittle, it is a good material for this purpose, because it is highly transparent (low optical losses), resistant to

text: ultraviolet light

text: (UV), fairly hard (abrasion resistant), chemically inert, and fairly easy to clean.  It is composed of a

text: float glass

text: with high optical transmission characteristics in the visible and

text: infrared

text: ranges, and is configured to transmit visible light and infrared radiation.  The top surface, known as the "first surface", will reflect some of the incident solar energy, due to the

text: reflection coefficient

text: caused by its

text: index of refraction

text: being higher than air.  Most of the solar energy is transmitted through the glass substrate to the lower layers of the mirror, possibly with some

text: refraction

text: , depending on the

text: angle of incidence

text: as light enters the mirror.

text: Typically the instrument schedule is organized first by hanging location.  Common hanging locations (or lighting positions) in theater include electrics, apron pipes, front of house positions, booms and ladders.  Within each position, instruments are numbered in the order they are located on the pipe.  The standard practice is to label instruments from stage left to right (for battens, and top to bottom for booms and ladders, although some lighting designers choose to label from stage right to stage left.  This is a matter of personal preference; it is only important that numbering is consistent.  This instrument number (or unit number) is used to sort the instruments in each lighting position on the instrument schedule.

text: Typically the instrument schedule is organized first by hanging location.  Common hanging locations (or lighting positions) in theater include electrics, apron pipes, front of house positions, booms and ladders.  Within each position, instruments are numbered in the order they are located on the pipe.  The standard practice is to label instruments from

text: stage left to right

text: (for

text: batten

text: s, and top to bottom for booms and ladders, although some lighting designers choose to label from stage right to stage left.  This is a matter of personal preference; it is only important that numbering is consistent.  This instrument number (or unit number) is used to sort the instruments in each lighting position on the instrument schedule.

text: The High Court said:Non-consideration of the relevant matters made the order of sanction illegal and resulted in failure of justice. We are thus of the opinion that the exercise of the power by the Governor was not in accordance with well-settled principles for sanctioning prosecution. We accordingly set aside the order of sanction, dated January 21, 2011, and remit the matter back to his Excellency, the Governor for reconsideration in the light of our discussions above.

text: The discussion on how much UV filtering is necessary in art framing is complex and controversial, driven by conflicting corporate interests. There have so far been no independent organizations, not tied to corporate sponsors, which have presented scientifically verifiable and conclusive evidence to the amount of UV filtering necessary for a glazing to both display and at the same time protect an artwork. On one hand, the issue is complicated by the varying amount of damaging light actually present in an indoor environment (from low level indirect sources to direct daylight). On the other, by the fact that not only UV, but also visible light damages an artwork. According to the National Fenestration Rating Council, only 40% of artwork fading is caused by UV radiation. The remaining damage comes from the visible light, heat, humidity and material chemistry. This means that increasing visible light transmission by an anti-reflective coating actually increases the amount of damaging radiation on an artwork.

text: The discussion on how much

text: UV

text: filtering is necessary in art framing is complex and controversial, driven by conflicting corporate interests. There have so far been no independent organizations, not tied to corporate sponsors, which have presented scientifically verifiable and conclusive evidence to the amount of UV filtering necessary for a glazing to both display and at the same time protect an artwork. On one hand, the issue is complicated by the varying amount of damaging light actually present in an indoor environment (from low level indirect sources to direct daylight). On the other, by the fact that not only

text: UV

text: , but also

text: visible light

text: damages an artwork. According to the National Fenestration Rating Council, only 40% of artwork fading is caused by UV radiation. The remaining damage comes from the visible light, heat, humidity and material chemistry. This means that increasing visible light transmission by an anti-reflective coating actually increases the amount of damaging radiation on an artwork.

text: In 2015 visible light joined microwave and infrared NIMs in propagating light in only one direction. ("mirrors" instead reduce light transmission in the reverse direction, requiring low light levels behind the mirror to work.)

text: In 2015 visible light joined microwave and infrared NIMs in propagating light in only one direction. ("

text: mirrors

text: " instead reduce light transmission in the reverse direction, requiring low light levels behind the mirror to work.)

text: In higher plants, the absorption of light continues to increase as light intensity increases, while the capacity for photosynthesis tends to saturate. Therefore there is the potential for the absorption of excess light energy by photosynthetic light harvesting systems. This excess excitation energy leads to an increase in the lifetime of singlet excited chlorophyll, increasing the chances of the formation of long-lived chlorophyll triplet states by inter-system crossing. Triplet chlorophyll is a potent photosensitiser of molecular oxygen forming singlet oxygen which can cause oxidative damage to the pigments, lipids and proteins of the photosynthetic thylakoid membrane. To counter this problem, one photoprotective mechanism is so-called non-photochemical quenching (NPQ), which relies upon the conversion and dissipation of the excess excitation energy into heat. NPQ involves conformational changes within the light harvesting proteins of photosystem (PS) II that bring about a change in pigment interactions causing the formation of energy traps. The conformational changes are stimulated by a combination of transmembrane proton gradient, the PsbS subunit of photosystem II and the enzymatic conversion of the carotenoid violaxanthin to zeaxanthin (the xanthophyll cycle).

text: In higher plants, the absorption of light continues to increase as light intensity increases, while the capacity for photosynthesis tends to saturate. Therefore there is the potential for the absorption of excess light energy by photosynthetic

text: light harvesting

text: systems. This excess excitation energy leads to an increase in the lifetime of singlet excited

text: chlorophyll

text: , increasing the chances of the formation of long-lived chlorophyll triplet states by

text: inter-system crossing

text: . Triplet chlorophyll is a potent

text: photosensitiser

text: of molecular oxygen forming

text: singlet oxygen

text: which can cause oxidative damage to the pigments, lipids and proteins of the photosynthetic

text: thylakoid membrane

text: . To counter this problem, one photoprotective mechanism is so-called non-photochemical quenching (NPQ), which relies upon the conversion and dissipation of the excess excitation energy into heat. NPQ involves conformational changes within the light harvesting proteins of photosystem (PS) II that bring about a change in pigment interactions causing the formation of energy traps. The conformational changes are stimulated by a combination of transmembrane proton gradient, the PsbS subunit of

text: photosystem II

text: and the enzymatic conversion of the carotenoid

text: violaxanthin

text: to

text: zeaxanthin

text: (the

text: xanthophyll cycle

text: In mathematics, a reflection (also spelled reflexion) is a mapping from a Euclidean space to itself that is an isometry with a hyperplane as a set of fixed points; this set is called the axis (in dimension 2) or plane (in dimension 3) of reflection. The image of a figure by a reflection is its mirror image in the axis or plane of reflection. For example the mirror image of the small Latin letter p for a reflection with respect to a vertical axis would look like q. Its image by reflection in a horizontal axis would look like b. A reflection is an involution: when applied twice in succession, every point returns to its original location, and every geometrical object is restored to its original state.

text: In

text: mathematics

text: , a reflection (also spelled reflexion) is a

text: mapping

text: from a

text: Euclidean space

text: to itself that is an

text: isometry

text: with a

text: hyperplane

text: as a set of

text: fixed point

text: s; this set is called the

text: axis

text: (in dimension 2) or

text: plane

text: (in dimension 3) of reflection. The image of a figure by a reflection is its

text: mirror image

text: in the axis or plane of reflection. For example the mirror image of the small Latin letter p for a reflection with respect to a vertical axis would look like q. Its image by reflection in a horizontal axis would look like b. A reflection is an

text: involution

text: : when applied twice in succession, every point returns to its original location, and every geometrical object is restored to its original state.

text: Furthermore, inside the big eyes, the transparent feeling of pupils and the glares, or small reflections in the corners of the eyes are often exaggerated, regardless of surrounding lighting, although they are only present in living characters: the eyes of characters who have died are the colour of the iris, but darker. Sometimes this death effect is also used to indicate characters who are emotionless due to trauma or loss of conscious control because of possession (ghost, demon, zombie, magic, etc.). In characters with hair partially covering the face, the eyes that would otherwise be covered are often outlined to make them visible, even when the hair is particularly dense and dark.

text: Furthermore, inside the big eyes, the transparent feeling of pupils and the glares, or

text: small reflections

text: in the corners of the eyes are often exaggerated, regardless of surrounding lighting, although they are only present in living characters: the eyes of characters who have died are the colour of the iris, but darker. Sometimes this death effect is also used to indicate characters who are emotionless due to trauma or loss of conscious control because of possession (ghost, demon, zombie, magic, etc.). In characters with hair partially covering the face, the eyes that would otherwise be covered are often outlined to make them visible, even when the hair is particularly dense and dark.

text: Light transmission. The variation of transmitted light through an aggregating suspension can be studied with a regular spectrophotometer in the visible region. As aggregation proceeds, the medium becomes more turbid, and its absorbance increases. The increase of the absorbance can be related to the aggregation rate constant k and the stability ratio can be estimated from such measurements. The advantage of thistechnique is its simplicity.

text: Light transmission. The variation of transmitted light through an aggregating suspension can be studied with a regular

text: spectrophotometer

text: in the visible region. As aggregation proceeds, the medium becomes more turbid, and its

text: absorbance

text: increases. The increase of the absorbance can be related to the aggregation rate constant k and the stability ratio can be estimated from such measurements. The advantage of thistechnique is its simplicity.

text: The idea of evolution by natural selection proposed by Charles Darwin put an end to these metaphysical theologies. In a letter to Joseph Dalton Hooker on 1 February 1871, Darwin discussed the suggestion that the original spark of life may have begun in a "warm little pond, with all sorts of ammonia and phosphoric salts, light, heat, electricity, , present, that a  compound was chemically formed ready to undergo still more complex changes." He went on to explain that "at the present day such matter would be instantly devoured or absorbed, which would not have been the case before living creatures were formed." He had written to Hooker in 1863 stating that, "It is mere rubbish, thinking at present of the origin of life; one might as well think of the origin of matter." In On the Origin of Species, he had referred to life having been "created", by which he "really meant 'appeared' by some wholly unknown process", but had soon regretted using the Old Testament term "creation".

text: The idea of

text: evolution

text: by

text: natural selection

text: proposed by

text: Charles Darwin

text: put an end to these metaphysical theologies. In a letter to

text: Joseph Dalton Hooker

text: on 1 February 1871, Darwin discussed the suggestion that the original spark of life may have begun in a "warm little pond, with all sorts of ammonia and phosphoric salts, light, heat, electricity, , present, that a  compound was chemically formed ready to undergo still more complex changes." He went on to explain that "at the present day such matter would be instantly devoured or absorbed, which would not have been the case before living creatures were formed." He had written to Hooker in 1863 stating that, "It is mere rubbish, thinking at present of the origin of life; one might as well think of the origin of matter." In

text: On the Origin of Species

text: , he had referred to life having been "created", by which he "really meant 'appeared' by some wholly unknown process", but had soon regretted using the Old Testament term "creation".

text: Photoacoustic spectroscopy is the measurement of the effect of absorbed electromagnetic energy (particularly of light) on matter by means of acoustic detection. The discovery of the photoacoustic effect dates to 1880 when Alexander Graham Bell showed that thin discs emitted sound when exposed to a beam of sunlight that was rapidly interrupted with a rotating slotted disk. The absorbed energy from the light causes local heating and through thermal expansion a pressure wave or sound. Later Bell showed that materials exposed to the non-visible portions of the solar spectrum (i.e., the infrared and the ultraviolet) can also produce sounds.

text: Photoacoustic spectroscopy is the measurement of the effect of absorbed

text: electromagnetic energy

text: (particularly of

text: light

text: ) on

text: matter

text: by means of

text: acoustic

text: detection. The discovery of the

text: photoacoustic effect

text: dates to 1880 when

text: Alexander Graham Bell

text: showed that thin discs emitted

text: sound

text: when exposed to a

text: beam

text: of

text: sunlight

text: that was rapidly interrupted with a rotating slotted disk. The

text: absorbed

text: energy

text: from the light causes local

text: heat

text: ing and through

text: thermal expansion

text: a

text: pressure

text: wave or sound. Later Bell showed that materials exposed to the non-visible portions of the solar

text: spectrum

text: (i.e., the

text: infrared

text: and the

text: ultraviolet

text: ) can also produce sounds.

text: Black is the color of objects that do not emit or reflect light in any part of the visible spectrum; they absorb all such frequencies of light. Black is the darkest possible color.

text: Black is the color of objects that do not emit or

text: reflect

text: light

text: in any part of the

text: visible spectrum

text: ; they absorb all such frequencies of light. Black is the darkest possible color.

text: The ventral side is decorated with ocelli (eyespots). In some species, such as M. godarti, the dorsal lamellae are so thin that ventral ocelli can peek through. While not all morphos have iridescent coloration, they all have ocelli. In most species, only the males are colorful, supporting the theory that the coloration is used for intrasexual communication between males. The lamellae reflect up to 70% of light falling on them, including any ultraviolet. The eyes of morpho butterflies are thought to be highly sensitive to UV light, so the males are able to see each other from great distances. Some South American species are reportedly visible to the human eye up to one kilometer away.

text: The ventral side is decorated with

text: ocelli

text: (eyespots). In some species, such as

text: M. godarti

text: , the dorsal lamellae are so thin that ventral ocelli can peek through. While not all morphos have iridescent coloration, they all have ocelli. In most species, only the males are colorful, supporting the theory that the coloration is used for intrasexual communication between males. The lamellae reflect up to 70% of light falling on them, including any

text: ultraviolet

text: . The eyes of morpho butterflies are thought to be highly sensitive to UV light, so the males are able to see each other from great distances. Some South American species are reportedly visible to the human eye up to one kilometer away.

text: Color centers are largely responsible for the appearance of specific wavelengths of visible light all around us. Moving from longer (0.7 micrometer) to shorter (0.4 micrometer) wavelengths: red, orange, yellow, green and blue (ROYGB) can all be identified by our senses in the appearance of color by the selective absorption of specific light wave frequencies (or wavelengths). Mechanisms of selective light wave absorption include:

text: The plasma state is often misunderstood, but it is actually quite common on Earth, and the majority of people observe it on a regular basis without even realizing it. Lightning, electric sparks, fluorescent lights, neon lights, plasma televisions, some types of flame and the stars are all examples of illuminated matter in the plasma state.

text: The plasma state is often misunderstood, but it is actually quite common on Earth, and the majority of people observe it on a regular basis without even realizing it.

text: Lightning

text: electric spark

text: s,

text: fluorescent lights

text: neon lights

text: plasma televisions

text: , some types of

text: flame

text: and the stars are all examples of illuminated matter in the plasma state.

text: Diffuse interstellar bands (DIBs) are absorption features seen in the spectra of astronomical objects in the Milky Way and other galaxies.  They are caused by the absorption of light by the interstellar medium. Circa 500 bands have now been seen, in ultraviolet, visible and infrared wavelengths.

text: Diffuse interstellar bands (DIBs) are

text: absorption

text: features seen in the

text: spectra

text: of

text: astronomical object

text: s in the

text: Milky Way

text: and other galaxies.  They are caused by the absorption of light by the

text: interstellar medium

text: . Circa 500 bands have now been seen, in

text: ultraviolet

text: visible

text: and

text: infrared

text: wavelengths.

text: The researchers had suggested that the motion may be a remnant of the influence of no-longer-visible regions of the universe prior to inflation. Telescopes cannot see events earlier than about 380,000 years after the Big Bang, when the universe became transparent (the cosmic microwave background); this corresponds to the particle horizon at a distance of about 46 billion (4.6×10) light years. Since the matter causing the net motion in this proposal is outside this range, it would in a certain sense be outside our visible universe; however, it would still be in our past light cone.

text: The researchers had suggested that the motion may be a remnant of the influence of no-longer-visible regions of the universe prior to

text: inflation

text: . Telescopes cannot see events earlier than about 380,000 years after the

text: Big Bang

text: , when the universe became transparent (the

text: cosmic microwave background

text: ); this corresponds to the

text: particle horizon

text: at a distance of about 46 billion (4.6×10)

text: light year

text: s. Since the matter causing the net motion in this proposal is outside this range, it would in a certain sense be outside our

text: visible universe

text: ; however, it would still be in our past

text: light cone

text: Since the dyes in processed film block various part of visible light but are all fairly transparent to infrared, dark black sections of any processed film (where all visible colors are blocked) pass only infrared light and are commonly used (layering one over another if necessary for better visual light filtering) as a cheap alternative to expensive glass-backed filters. Such filters can be used both over color camera lenses, and to filter visible light from IR illumination sources. Such filter stock is most easily made available most simply by having any commercial color negative film developed after being fully exposed to light. The leaders of 35mm film are ideal for this, without wasting an entire roll of film. (Some special communication may be necessary in such submission, to ensure that all of the "black" negative film thus produced is indeed returned, and that there is no need to print the color-negative results on photographic paper). In the same way, visually opaque "black" color-positive film emulsions mounted in cardboard, as for routine slide projection, provide inexpensive cardboard-mounted infrared filters. Film sizes larger than 35 mm may be handled in the same way for larger filter production.

text: Many samples of fluorite exhibit fluorescence under ultraviolet light, a property that takes its name from fluorite. Many minerals, as well as other substances, fluoresce. Fluorescence involves the elevation of electron energy levels by quanta of ultraviolet light, followed by the progressive falling back of the electrons into their previous energy state, releasing quanta of visible light in the process. In fluorite, the visible light emitted is most commonly blue, but red, purple, yellow, green and white also occur. The fluorescence of fluorite may be due to mineral impurities, such as yttrium and ytterbium, or organic matter, such as volatile hydrocarbons in the crystal lattice. In particular, the blue fluorescence seen in fluorites from certain parts of Great Britain responsible for the naming of the phenomenon of fluorescence itself, has been attributed to the presence of inclusions of divalent europium in the crystal.

text: Many samples of fluorite exhibit

text: fluorescence

text: under

text: ultraviolet light

text: , a property that takes its name from fluorite. Many minerals, as well as other substances, fluoresce. Fluorescence involves the elevation of electron energy levels by quanta of ultraviolet light, followed by the progressive falling back of the electrons into their previous energy state, releasing quanta of visible light in the process. In fluorite, the visible light emitted is most commonly blue, but red, purple, yellow, green and white also occur. The fluorescence of fluorite may be due to mineral impurities, such as

text: yttrium

text: and

text: ytterbium

text: , or organic matter, such as volatile

text: hydrocarbons

text: in the crystal lattice. In particular, the blue fluorescence seen in fluorites from certain parts of

text: Great Britain

text: responsible for the naming of the phenomenon of fluorescence itself, has been attributed to the presence of inclusions of divalent

text: europium

text: in the crystal.

text: Absorption coefficients for 200 nm and 900 nm are almost equal at 6.9 m (attenuation length of 14.5 cm). Very weak light absorption, in the visible region, by liquid water has been measured using an integrating cavity absorption meter (ICAM). The absorption was attributed to a sequence of overtone and combination bands whose intensity decreases at each step, giving rise to an absolute minimum at 418 nm, at which wavelength the attenuation coefficient is about 0.0044 m, which is an attenuation length of about 227 meters. These values correspond to pure absorption without scattering effects. The attenuation of, e.g., a laser beam would be slightly stronger.

text: Absorption coefficients

text: for 200 nm and 900 nm are almost equal at 6.9 m (

text: attenuation length

text: of 14.5 cm). Very weak light absorption, in the visible region, by liquid water has been measured using an integrating cavity absorption meter (ICAM). The absorption was attributed to a sequence of overtone and combination bands whose intensity decreases at each step, giving rise to an absolute minimum at 418 nm, at which wavelength the attenuation coefficient is about 0.0044 m, which is an attenuation length of about 227 meters. These values correspond to pure absorption without scattering effects. The attenuation of, e.g., a laser beam would be slightly stronger.

text: This situation presented the matter in the most favorable light, far from the solitary, involuntary deaths of those killed by the program under a very broad definition of "incurably ill."

text: Though the IR from a DPSS laser is less collimated, the typical neodymium-doped crystals in such lasers do produce a true IR laser beam. The eye will usually react to the higher-powered visible light; however in higher power DPSS lasers the IR laser output can be significant. What poses a special hazard for this unfiltered IR output is its presence in conjunction with laser safety goggles designed to only block the visible wavelengths of the laser. Red goggles, for example, will block most green light from entering the eyes, but will pass IR light. The reduced light behind the goggles may also cause the pupils to dilate, increasing the hazard to the invisible IR light. Dual-frequency so-called YAG laser eyewear is significantly more expensive than single frequency laser eyewear, and is often not supplied with unfiltered DPSS pointer style lasers, which output 1064 nm IR laser light as well. These potentially hazardous lasers produce little or no visible beam when shone through the eyewear supplied with them, yet their IR-laser output can still be easily seen when viewed with an IR-sensitive video camera.

text: Though the IR from a DPSS laser is less collimated, the typical

text: neodymium-doped crystals

text: in such lasers do produce a true IR laser beam. The eye will usually react to the higher-powered visible light; however in higher power DPSS lasers the IR laser output can be significant. What poses a special hazard for this unfiltered IR output is its presence in conjunction with laser safety goggles designed to only block the visible wavelengths of the laser. Red goggles, for example, will block most green light from entering the eyes, but will pass IR light. The reduced light behind the goggles may also cause the pupils to dilate, increasing the hazard to the invisible IR light. Dual-frequency so-called YAG laser eyewear is significantly more expensive than single frequency laser eyewear, and is often not supplied with unfiltered DPSS pointer style lasers, which output 1064 nm IR laser light as well. These potentially hazardous lasers produce little or no visible beam when shone through the eyewear supplied with them, yet their IR-laser output can still be easily seen when viewed with an IR-sensitive video camera.

text: Recall from the descriptions of absorption and stimulated emission above that the rates of these two processes are proportional to the number of atoms in the ground and excited states, N and N, respectively. If the ground state has a higher population than the excited state (N > N), then the absorption process dominates, and there is a net attenuation of photons. If the populations of the two states are the same (N = N), the rate of absorption of light exactly balances the rate of emission; the medium is then said to be optically transparent.

text: In order to overcome the limitations set by the diffraction limit of visible light other microscopes have been designed which use other waves.

text: The advent of deep photographic imaging allowed Edward Barnard to produce the first images of dark nebulae silhouetted against the background star field of the galaxy, while the first actual detection of cold diffuse matter in interstellar space was made by Johannes Hartmann in 1904 through the use of absorption line spectroscopy. In his historic study of the spectrum and orbit of Delta Orionis, Hartmann observed the light coming from this star and realized that some of this light was being absorbed before it reached the Earth. Hartmann reported that absorption from the "K" line of calcium appeared "extraordinarily weak, but almost perfectly sharp" and also reported the "quite surprising result that the calcium line at 393.4 nanometres does not share in the periodic displacements of the lines caused by the orbital motion of the spectroscopic binary star". The stationary nature of the line led Hartmann to conclude that the gas responsible for the absorption was not present in the atmosphere of Delta Orionis, but was instead located within an isolated cloud of matter residing somewhere along the line-of-sight to this star. This discovery launched the study of the Interstellar Medium.

text: The advent of deep photographic imaging allowed

text: Edward Barnard

text: to produce the first images of

text: dark nebula

text: e silhouetted against the background star field of the galaxy, while the first actual detection of cold diffuse matter in interstellar space was made by

text: Johannes Hartmann

text: in 1904 through the use of

text: absorption line spectroscopy

text: . In his historic study of the spectrum and orbit of

text: Delta Orionis

text: , Hartmann observed the light coming from this star and realized that some of this light was being absorbed before it reached the Earth. Hartmann reported that absorption from the "K" line of

text: calcium

text: appeared "extraordinarily weak, but almost perfectly sharp" and also reported the "quite surprising result that the calcium line at 393.4 nanometres does not share in the periodic displacements of the lines caused by the orbital motion of the

text: spectroscopic binary

text: star". The stationary nature of the line led Hartmann to conclude that the gas responsible for the absorption was not present in the atmosphere of Delta Orionis, but was instead located within an isolated cloud of matter residing somewhere along the line-of-sight to this star. This discovery launched the study of the Interstellar Medium.

text: part); the Hamiltonian also contains the Hermitian conjugate (abbreviated as h.c.) of the terms that are explicitly written. The coupling strength between light and matter is defined by

text: part); the Hamiltonian also contains the

text: Hermitian conjugate

text: (abbreviated as h.c.) of the terms that are explicitly written. The

text: coupling strength

text: between light and matter is defined by

text: Songs included "Friville", "The Lass with the Lasso", "Three Little Pebbles" and "Ladies, Beware! (When the Lights are low)".  Critics praised Stuart's score but observed that the plot of the piece was thin.  But they concluded that this did not matter:

text: The study of light and the interaction of light and matter is termed optics. The observation and study of optical phenomena such as rainbows and the aurora borealis offer many clues as to the nature of light.

text: The study of light and the interaction of light and

text: matter

text: is termed

text: optics

text: . The observation and study of

text: optical phenomena

text: such as

text: rainbow

text: s and the

text: aurora borealis

text: offer many clues as to the nature of light.

text: The non-ionizing portion of electromagnetic radiation consists of electromagnetic waves that (as individual quanta or particles, see photon) are not energetic enough to detach electrons from atoms or molecules and hence cause their ionization. These include radio waves, microwaves, infrared, and (sometimes) visible light. The lower frequencies of ultraviolet light may cause chemical changes and molecular damage similar to ionization, but is technically not ionizing. The highest frequencies of ultraviolet light, as well as all X-rays and gamma-rays are ionizing.

text: The non-ionizing portion of electromagnetic radiation consists of electromagnetic waves that (as individual quanta or particles, see

text: photon

text: ) are not energetic enough to detach electrons from atoms or molecules and hence cause their ionization. These include radio waves, microwaves, infrared, and (sometimes) visible light. The lower frequencies of ultraviolet light may cause chemical changes and molecular damage similar to ionization, but is technically not ionizing. The highest frequencies of ultraviolet light, as well as all X-rays and gamma-rays are ionizing.

text: In the model, Einstein derived simple expressions relating the density of matter, the radius of the universe and the timespan of the expansion to the Hubble constant. With the use of the contemporaneous value of  500 kmsMpc for the Hubble constant, he calculated values of 10 cm, 10 light-years and 10 years for the density of matter, the radius of the universe and the timespan of the expansion respectively. It has recently been shown that these calculations contain a slight systematic error.

text: In the model, Einstein derived simple expressions relating the density of matter, the radius of the universe and the timespan of the expansion to the

text: Hubble constant

text: . With the use of the contemporaneous value of  500 kmsMpc for the Hubble constant, he calculated values of 10 cm, 10 light-years and 10 years for the density of matter, the radius of the universe and the timespan of the expansion respectively. It has recently been shown that these calculations contain a slight systematic error.

text: In 1932, Jan Hendrik Oort became the first to report that measurements of the stars in the Solar neighborhood moved faster than expected when a mass distribution based upon visible matter was assumed, but this measurement was later determined to be essentially erroneous. In 1939, Horace Babcock reported in his PhD thesis measurements of the rotation curve for Andromeda which suggested that the mass-to-luminosity ratio increases radially. He attributed that to either the absorption of light within the galaxy or to modified dynamics in the outer portions of the spiral and not to any form of missing matter. In 1959, Louise Volders demonstrated that spiral galaxy M33 does not spin as expected according to Keplerian dynamics. In the late 1960s and early 1970s, Vera Rubin, an astronomer at the Department of Terrestrial Magnetism at the Carnegie Institution of Washington worked with a new sensitive spectrograph that could measure the velocity curve of edge-on spiral galaxies to a greater degree of accuracy than had ever before been achieved. Together with fellow staff-member Kent Ford, Rubin announced at a 1975 meeting of the American Astronomical Society the discovery that most stars in spiral galaxies orbit at roughly the same speed, and that this implied that galaxy masses grow approximately linearly with radius well beyond the location of most of the stars (the galactic bulge).  Rubin presented her results in an influential paper in 1980. These were the first robust results to suggest that either Newtonian gravity does not apply universally or that, conservatively, upwards of 50% of the mass of galaxies was contained in the relatively dark galactic halo. Although initially met with skepticism,  Rubin's results have been confirmed over the subsequent decades.

text: In 1932,

text: Jan Hendrik Oort

text: became the first to report that measurements of the stars in the

text: Solar neighborhood

text: moved faster than expected when a mass distribution based upon visible matter was assumed, but this measurement was later determined to be essentially erroneous. In 1939,

text: Horace Babcock

text: reported in his PhD thesis measurements of the rotation curve for Andromeda which suggested that the mass-to-luminosity ratio increases radially. He attributed that to either the absorption of light within the galaxy or to modified dynamics in the outer portions of the spiral and not to any form of missing matter. In 1959, Louise Volders demonstrated that spiral galaxy

text: does not spin as expected according to

text: Keplerian dynamics

text: . In the late 1960s and early 1970s,

text: Vera Rubin

text: , an astronomer at the Department of Terrestrial Magnetism at the

text: Carnegie Institution of Washington

text: worked with a new sensitive

text: spectrograph

text: that could measure the velocity curve of edge-on

text: spiral galaxies

text: to a greater degree of accuracy than had ever before been achieved. Together with fellow staff-member

text: Kent Ford

text: , Rubin announced at a 1975 meeting of the

text: American Astronomical Society

text: the discovery that most

text: star

text: s in

text: spiral galaxies

text: orbit at roughly the same speed, and that this implied that galaxy masses grow approximately linearly with radius well beyond the location of most of the stars (the

text: galactic bulge

text: ).  Rubin presented her results in an influential paper in 1980. These were the first robust results to suggest that either

text: Newtonian gravity

text: does not apply universally or that, conservatively, upwards of 50% of the mass of galaxies was contained in the relatively dark galactic halo. Although initially met with skepticism,  Rubin's results have been confirmed over the subsequent decades.

text: The same phenomenon, considered from a different viewpoint, is described by a beam of particles of momentum  incident at angle  upon the same array of crystal atomic planes. It is supposed that a collective of  such atomic planes reflects the particle, transferring to it a momentum , where  is a momentum characteristic of the reflecting planes, in the direction perpendicular to them. The reflection is elastic, with negligible transfer of kinetic energy, because the crystal is massive. The initial momentum of the particle in the direction perpendicular to the reflecting planes was . For reflection, the change of momentum of the particle in that direction must be . Consequently

text: The Spectronic 20 is a single-beam spectrophotometer, designed to operate in the visible spectrum across a wavelength range of 340 nm to 950 nm, with a spectral bandwidth of 20 nm. Because it measures the transmittance or absorption of visible light through a solution, it is sometimes referred to as a colorimeter.

text: The Spectronic 20 is a single-beam

text: spectrophotometer

text: , designed to operate in the

text: visible spectrum

text: across a wavelength range of 340

text: nm

text: to 950 nm, with a spectral bandwidth of 20 nm. Because it measures the

text: transmittance

text: or

text: absorption

text: of visible light through a

text: solution

text: , it is sometimes referred to as a

text: colorimeter

text: Jan Tauc () showed that the optical absorption spectrum of amorphous germanium resembles the spectrum of the  indirect transitions in crystalline germanium (plus a tail due to localized states at lower energies), and proposed an extrapolation to find the optical gap of these crystalline-like states. Typically, a Tauc plot shows the quantity hν (the energy of the light) on the abscissa and the quantity (αhν)  on the ordinate, where α is the absorption coefficient of the material. The value of the exponent r denotes the nature of the transition:

text: Jan Tauc

text: () showed that the optical

text: absorption spectrum

text: of amorphous

text: germanium

text: resembles the spectrum of the

text: indirect transitions

text: in

text: crystalline

text: germanium (plus a tail due to localized states at lower energies), and proposed an extrapolation to find the optical gap of these crystalline-like states. Typically, a Tauc plot shows the quantity hν (the energy of the light) on the abscissa and the quantity (αhν)  on the ordinate, where α is the absorption coefficient of the material. The value of the exponent r denotes the nature of the transition:

text: Furthermore, electromagnetic energy is light energy, but only a small part of it is visible light. This energy travels in waves. Shorter wavelengths, such as visible light and infrared, carry more energy per photon than longer waves, such as microwaves and radio waves. For the sciences, the light spectrum is known as the electromagnetic spectrum.

text: Furthermore, electromagnetic energy is light energy, but only a small part of it is

text: visible light

text: . This energy travels in waves. Shorter wavelengths, such as visible light and

text: infrared

text: , carry more energy per

text: photon

text: than longer waves, such as

text: microwave

text: s and

text: radio waves

text: . For the

text: science

text: s, the light spectrum is known as the

text: electromagnetic spectrum

text: Most cars sold in North America since the 1950s have been available with an automatic transmission based on the fact that the three major American car manufacturers had started using automatics. Conversely, in Europe a manual gearbox is standard, with 20% of drivers opting for an automatic transmission. In some Asian markets and in Australia, automatic transmissions have become very popular since the 1980s.

text: Most cars sold in

text: North America

text: since the 1950s have been available with an automatic transmission based on the fact that the three major American car manufacturers had started using automatics. Conversely, in

text: Europe

text: a manual gearbox is standard, with 20% of drivers opting for an automatic transmission. In some Asian markets and in Australia, automatic transmissions have become very popular since the 1980s.

text: If a laser beam is swept quickly across a distant object, the spot of light can move faster than c, although the initial movement of the spot is delayed because of the time it takes light to get to the distant object at the speed c. However, the only physical entities that are moving are the laser and its emitted light, which travels at the speed c from the laser to the various positions of the spot. Similarly, a shadow projected onto a distant object can be made to move faster than c, after a delay in time. In neither case does any matter, energy, or information travel faster than light.

text: Absorption is the process by which a photon is absorbed by the atom, causing an electron to jump from a lower energy level to a higher one. The process is described by the Einstein coefficient

text: Often, a transmission has multiple gear ratios (or simply "gears") with the ability to switch between them as speed varies. This switching may be done manually (by the operator) or automatically. Directional (forward and reverse) control may also be provided. Single-ratio transmissions also exist, which simply change the speed and torque (and sometimes direction) of motor output.

text: Light in the visible electromagnetic spectrum can traverse a couple meters of pure water (or ice) without significant absorption, so that it looks transparent and colorless.  Thus aquatic plants, algae, and other photosynthetic organisms can live in water up to hundreds of meters deep, because sunlight can reach them.   Water vapour is essentially invisible as a gas.

text: Light in the visible

text: electromagnetic spectrum

text: can traverse a couple

text: meter

text: s of pure water (or ice) without significant

text: absorption

text: , so that it looks

text: transparent

text: and colorless.  Thus

text: aquatic plant

text: s,

text: alga

text: e, and other

text: photosynthetic

text: organisms can live in water up to hundreds of meters deep, because

text: sunlight

text: can reach them.   Water vapour is essentially invisible as a gas.

text: Digital camera sensors are inherently sensitive to infrared light, which would interfere with the normal photography by confusing the autofocus calculations or softening the image (because infrared light is focused differently from visible light), or oversaturating the red channel. Also, some clothing is transparent in the infrared, leading to unintended (at least to the manufacturer) uses of video cameras. Thus, to improve image quality and protect privacy, many digital cameras employ infrared blockers. Depending on the subject matter, infrared photography may not be practical with these cameras because the exposure times become overly long, often in the range of 30 seconds, creating noise and motion blur in the final image. However, for some subject matter the long exposure does not matter or the motion blur effects actually add to the image. Some lenses will also show a 'hot spot' in the centre of the image as their coatings are optimised for visible light and not for IR.

text: Digital camera

text: sensors are inherently sensitive to infrared light, which would interfere with the normal photography by confusing the

text: autofocus

text: calculations or softening the image (because infrared light is focused differently from visible light), or oversaturating the red channel. Also, some clothing is transparent in the infrared, leading to unintended (at least to the manufacturer) uses of

text: video camera

text: s. Thus, to improve image quality and protect privacy, many digital cameras employ infrared

text: blockers

text: . Depending on the subject matter, infrared photography may not be practical with these cameras because the exposure times become overly long, often in the range of 30 seconds, creating

text: noise

text: and

text: motion blur

text: in the final image. However, for some subject matter the long exposure does not matter or the motion blur effects actually add to the image. Some lenses will also show a 'hot spot' in the centre of the image as their

text: coatings

text: are optimised for visible light and not for IR.

text: Light levels need to be measured when the exhibition is prepared. UV light meters will check radiation levels in an exhibit space, and data event loggers help determine visible light levels over an extended period of time. Blue wool standards cards can also be utilized to predict the extent to which materials will be damaged during exhibits. UV radiation must be eliminated to the extent it is physically possible; it is recommended that light with a wavelength below 400 nm (ultraviolet radiation) be limited to no more than 75 microwatts per lumen at 10 to 100 lux. Furthermore, exposure to natural light is undesirable because of its intensity and high UV content. When such exposure is unavoidable, preventative measures must be taken to control UV radiation, including the use of blinds, shades, curtains, UV filtering films, and UV-filtering panels in windows or cases. Artificial light sources are safer options for exhibition. Among these sources, incandescent lamps are most suitable because they emit little or no UV radiation.  Fluorescent lamps, common in most institutions, may be used only when they produce a low UV output and when covered with plastic sleeves before exhibition.  Though tungsten-halogen lamps are currently a favorite artificial lighting source, they still give off significant amounts of UV radiation; use these only with special UV filters and dimmers.  Lights should be lowered or turned off completely when visitors are not in the exhibition space.

text: Light levels need to be measured when the exhibition is prepared.

text: UV

text: light meters will check radiation levels in an exhibit space, and data event loggers help determine visible light levels over an extended period of time. Blue wool standards cards can also be utilized to predict the extent to which materials will be damaged during exhibits. UV

text: radiation

text: must be eliminated to the extent it is physically possible; it is recommended that light with a wavelength below 400

text: nm

text: (ultraviolet radiation) be limited to no more than 75

text: microwatts

text: per

text: lumen

text: at 10 to 100 lux. Furthermore, exposure to

text: natural light

text: is undesirable because of its intensity and high UV content. When such exposure is unavoidable, preventative measures must be taken to control UV radiation, including the use of blinds, shades, curtains,

text: UV filter

text: ing films, and UV-filtering panels in windows or cases.

text: Artificial light

text: sources are safer options for exhibition. Among these sources,

text: incandescent lamps

text: are most suitable because they emit little or no UV radiation.

text: Fluorescent lamp

text: s, common in most institutions, may be used only when they produce a low UV output and when covered with plastic sleeves before exhibition.  Though

text: tungsten-halogen lamps

text: are currently a favorite artificial lighting source, they still give off significant amounts of UV radiation; use these only with special UV filters and dimmers.  Lights should be lowered or turned off completely when visitors are not in the exhibition space.

text: The Stanford Synchrotron Radiation Lightsource (formerly Stanford Synchrotron Radiation Laboratory), a division of SLAC National Accelerator Laboratory, is operated by Stanford University for the Department of Energy. SSRL is a National User Facility which provides synchrotron radiation, a name given to electromagnetic radiation in the x-ray, ultraviolet, visible and infrared realms produced by electrons circulating in a storage ring (Stanford Positron Electron Asymmetric Ring - SPEAR) at nearly the speed of light. The extremely bright light that is produced can be used to investigate various forms of matter ranging from objects of atomic and molecular size to man-made materials with unusual properties. The obtained information and knowledge is of great value to society, with impact in areas such as the environment, future technologies, health, and education.

text: The Stanford Synchrotron Radiation Lightsource (formerly Stanford Synchrotron Radiation Laboratory), a division of

text: SLAC National Accelerator Laboratory

text: , is operated by

text: Stanford University

text: for the

text: Department of Energy

text: . SSRL is a National User Facility which provides

text: synchrotron radiation

text: , a name given to electromagnetic radiation in the x-ray, ultraviolet, visible and infrared realms produced by electrons circulating in a

text: storage ring

text: (Stanford Positron Electron Asymmetric Ring -

text: SPEAR

text: ) at nearly the speed of light. The extremely bright light that is produced can be used to investigate various forms of matter ranging from objects of atomic and molecular size to man-made materials with unusual properties. The obtained information and knowledge is of great value to society, with impact in areas such as the environment, future technologies, health, and education.

text: After coherence is created in a sample by light, the sample emits a polarization wave, the frequency of which is equal to and the phase of which is inverted from the incident light. In addition, the sample is excited by the incident light and a population of molecules in the excited state is generated. The light passing through the sample is absorbed because of these two processes, and it is expressed by an absorption spectrum. The coherence decays with the time constant, T, and the intensity of the polarization wave is reduced. The population of the excited state also decays with the time constant of the longitudinal relaxation, T. The time constant T is usually much smaller than T, and the bandwidth of the absorption spectrum is related to these time constants by the Fourier transform, so the time constant T is a main contributor to the bandwidth. The time constant T has been measured with ultrafast time-resolved spectroscopy directly, such as in photon echo experiments.

text: After coherence is created in a sample by light, the sample emits a

text: polarization wave

text: , the frequency of which is equal to and the

text: phase

text: of which is inverted from the incident light. In addition, the sample is excited by the incident light and a population of molecules in the excited state is generated. The light passing through the sample is absorbed because of these two processes, and it is expressed by an

text: absorption spectrum

text: . The coherence decays with the time constant, T, and the intensity of the polarization wave is reduced. The population of the excited state also decays with the time constant of the

text: longitudinal relaxation

text: , T. The time constant T is usually much smaller than T, and the bandwidth of the absorption spectrum is related to these time constants by the

text: Fourier transform

text: , so the time constant T is a main contributor to the bandwidth. The time constant T has been measured with ultrafast

text: time-resolved spectroscopy

text: directly, such as in photon echo experiments.

text: Because its shiny surface the large balloon-like satellite was also reflective of visible light rays, Echo 1A was visible to the naked eye over most of the Earth. Echo 1 was a passive communications satellite: it functioned as a reflector, not a transmitter. After it was placed in a low Earth orbit (LEO), a signal would be transmitted from Earth to the Echo satellite and then reflected or bounced off its surface, and then returned to Earth.  It was the pioneer of communications satellites. Because it was brighter than most stars, it was seen by more people than any other man-made object in space at that time.  Upon reentry into Earth's atmosphere ECHO 1A burned up on May 24, 1968.

text: Upon absorption of light, fluorescent materials emit light upon of a longer wavelength (lower energy) than the absorbed radiation, but cease to do so once immediately, when the illumination is stopped. The tagging of stamps uses substances that absorb ultraviolet light of wavelengths between 300 nm and 450 nm ("Black light", UVA, long-wave UV) and emit light in the visible spectrum. Under UV illumination they usually glow a greenish or yellowish colour.

text: Upon absorption of light, fluorescent materials emit light upon of a longer wavelength (lower energy) than the absorbed radiation, but cease to do so once immediately, when the illumination is stopped. The tagging of stamps uses substances that absorb ultraviolet light of wavelengths between 300 nm and 450 nm ("

text: Black light

text: ", UVA, long-wave UV) and emit light in the visible spectrum. Under UV illumination they usually glow a greenish or yellowish colour.

text: When a liquid solvent absorbs a gas mixture or part of it, a mass of gas moves into the liquid. For example, water may absorb oxygen from the air. This mass transfer takes place at the interface between the liquid and the gas, at a rate depending on both the gas and the liquid. This type of absorption depends on the solubility of gases, the pressure and the temperature. The rate and amount of absorption also depend on the surface area of the interface and its duration in time. For example, when the water is finely divided and mixed with air, as may happen in a waterfall or a strong ocean surf, the water absorbs more oxygen.

text: Dark matter can be divided into cold, warm and hot categories. These categories refer to velocity rather than an actual temperature, indicating how far corresponding objects moved due to random motions in the early universe, before they slowed due to cosmic expansion – this is an important distance called the "free streaming length" (FSL). Primordial density fluctuations smaller than this length get washed out as particles spread from overdense to underdense regions, while larger fluctuations are unaffected; therefore this length sets a minimum scale for later structure formation. The categories are set with respect to the size of a protogalaxy (an object that later evolves into a dwarf galaxy): dark matter particles are classified as cold, warm, or hot according as their FSL; much smaller (cold), similar (warm), or much larger (hot) than a protogalaxy.

text: Dark matter can be divided into cold, warm and hot categories. These categories refer to velocity rather than an actual temperature, indicating how far corresponding objects moved due to random motions in the early universe, before they slowed due to cosmic expansion – this is an important distance called the "

text: free streaming length

text: " (FSL). Primordial density fluctuations smaller than this length get washed out as particles spread from overdense to underdense regions, while larger fluctuations are unaffected; therefore this length sets a minimum scale for later structure formation. The categories are set with respect to the size of a

text: protogalaxy

text: (an object that later evolves into a dwarf galaxy): dark matter particles are classified as cold, warm, or hot according as their FSL; much smaller (cold), similar (warm), or much larger (hot) than a protogalaxy.

text: UV-visible spectroscopy of microscopic samples is done by integrating an optical microscope with UV-visible optics, white light sources, a monochromator, and a sensitive detector such as a charge-coupled device (CCD) or photomultiplier tube (PMT). As only a single optical path is available, these are single beam instruments. Modern instruments are capable of measuring UV-visible spectra in both reflectance and transmission of micron-scale sampling areas. The advantages of using such instruments is that they are able to measure microscopic samples but are also able to measure the spectra of larger samples with high spatial resolution. As such, they are used in the forensic laboratory to analyze the dyes and pigments in individual textile fibers, microscopic paint chips  and the color of glass fragments. They are also used in materials science and biological research and for determining the energy content of coal and petroleum source rock by measuring the vitrinite reflectance. Microspectrophotometers are used in the semiconductor and micro-optics industries for monitoring the thickness of thin films after they have been deposited. In the semiconductor industry, they are used because the critical dimensions of circuitry is microscopic. A typical test of a semiconductor wafer would entail the acquisition of spectra from many points on a patterned or unpatterned wafer. The thickness of the deposited films may be calculated from the interference pattern of the spectra. In addition, ultraviolet-visible spectrophotometry can be used to determine the thickness, along with the refractive index and extinction coefficient of thin films as described in Refractive index and extinction coefficient of thin film materials. A map of the film thickness across the entire wafer can then be generated and used for quality control purposes.

text: UV-visible spectroscopy of microscopic samples is done by integrating an optical microscope with UV-visible optics, white light sources, a

text: monochromator

text: , and a sensitive detector such as a

text: charge-coupled device

text: (CCD) or

text: photomultiplier

text: tube (PMT). As only a single optical path is available, these are single beam instruments. Modern instruments are capable of measuring UV-visible spectra in both reflectance and transmission of micron-scale sampling areas. The advantages of using such instruments is that they are able to measure microscopic samples but are also able to measure the spectra of larger samples with high spatial resolution. As such, they are used in the forensic laboratory to analyze the dyes and pigments in individual textile fibers, microscopic paint chips  and the color of glass fragments. They are also used in materials science and biological research and for determining the energy content of coal and petroleum source rock by measuring the

text: vitrinite

text: reflectance. Microspectrophotometers are used in the semiconductor and micro-optics industries for monitoring the thickness of thin films after they have been deposited. In the semiconductor industry, they are used because the critical dimensions of circuitry is microscopic. A typical test of a semiconductor wafer would entail the acquisition of spectra from many points on a patterned or unpatterned wafer. The thickness of the deposited films may be calculated from the

text: interference pattern

text: of the spectra. In addition, ultraviolet-visible spectrophotometry can be used to determine the thickness, along with the refractive index and extinction coefficient of thin films as described in

entity_name: Refractive index and extinction coefficient of thin film materials

text: Refractive index and extinction coefficient of thin film materials

text: . A map of the film thickness across the entire wafer can then be generated and used for quality control purposes.

text: Enchanted by the play of light and reflections which transformed the appearance of matter, Riesener began a new aesthetic that made him one of the precursors of impressionism. A passionate colourist, he researched all the nuances of colour and studied the techniques of ancient Greece and the Renaissance, including Titian, Veronese and Corregio. Impressed by his research into colour, he turned towards Rubens, which for him was the Shakespeare of painting. Very early in his career Riesener studied tonal divisions, well before the physician Chevreul discovered their scientific basis. His tactile taste led him to look for the most perfect expression of matter and particularly of skin. He put poetry into his painting by the play of shadow and he passionately admired nature, life and all the beauties they produced.

text: Enchanted by the play of light and reflections which transformed the appearance of matter, Riesener began a new aesthetic that made him one of the precursors of

text: impressionism

text: . A passionate

text: colourist

text: , he researched all the nuances of colour and studied the techniques of ancient Greece and the Renaissance, including

text: Titian

text: Veronese

text: and

text: Corregio

text: . Impressed by his research into colour, he turned towards

text: Rubens

text: , which for him was the

text: Shakespeare

text: of painting. Very early in his career Riesener studied tonal divisions, well before the physician Chevreul discovered their scientific basis. His tactile taste led him to look for the most perfect expression of matter and particularly of skin. He put poetry into his painting by the play of shadow and he passionately admired nature, life and all the beauties they produced.

text: When light strikes an object, it usually has not just a single frequency (or wavelength) but many. Objects have a tendency to selectively absorb, reflect or transmit light of certain frequencies. That is, one object might reflect green light while absorbing all other frequencies of visible light. Another object might selectively transmit blue light while absorbing all other frequencies of visible light. The manner in which visible light interacts with an object is dependent upon the frequency of the light, the nature of the atoms in the object, and often the nature of the electrons in the atoms of the object.

text: When light strikes an object, it usually has not just a single frequency (or wavelength) but many. Objects have a tendency to selectively absorb, reflect or transmit light of certain frequencies. That is, one object might reflect green light while absorbing all other frequencies of visible light. Another object might selectively transmit blue light while absorbing all other frequencies of visible light. The manner in which visible light interacts with an object is dependent upon the frequency of the light, the nature of the atoms in the object, and often the nature of the

text: electron

text: s in the

text: atom

text: s of the object.

text: An outdoor television set  designed for outdoor use is usually found in the outdoor sections of bars, sports fields, or other community facilities. Most outdoor televisions use High-definition television technology. Their body is more robust. The screens are designed to remain clearly visible even in sunny outdoor lighting. The screens also have anti-reflective coatings to prevent glare. They are weather-resistant and often also have anti-theft brackets. Outdoor TV models can also be connected with BD players and PVRs for greater functionality.

text: An outdoor television set  designed for outdoor use is usually found in the outdoor sections of

text: bar

text: s, sports fields, or other community facilities. Most outdoor televisions use

text: High-definition television

text: technology. Their body is more robust. The screens are designed to remain clearly visible even in sunny outdoor lighting. The screens also have anti-reflective coatings to prevent glare. They are weather-resistant and often also have anti-theft brackets. Outdoor TV models can also be connected with

text: BD player

text: s and

text: PVRs

text: for greater functionality.

text: Transient-absorption spectroscopy, also known as flash spectroscopy, is an extension of absorption spectroscopy. Ultrafast transient absorption spectroscopy, an example of non-linear spectroscopy, measures changes in the absorbance/transmittance in the sample. Here, the absorbance at a particular wavelength or range of wavelengths of a sample is measured as a function of time after excitation by a flash of light. In a typical experiment, both the light for excitation ('pump') and the light for measuring the absorbance ('probe') are generated by a pulsed laser. If the process under study is slow, then the time resolution can be obtained with a continuous (i.e., not pulsed) probe beam and repeated conventional spectrophotometric techniques.

text: Transient-absorption spectroscopy, also known as flash spectroscopy, is an extension of

text: absorption spectroscopy

text: . Ultrafast transient absorption spectroscopy, an example of non-linear spectroscopy, measures changes in the

text: absorbance

text: transmittance

text: in the sample. Here, the

text: absorbance

text: at a particular

text: wavelength

text: or range of wavelengths of a sample is measured as a function of time after

text: excitation

text: by a flash of light. In a typical experiment, both the light for excitation ('pump') and the light for measuring the absorbance ('probe') are generated by a pulsed laser. If the process under study is slow, then the time resolution can be obtained with a continuous (i.e., not pulsed) probe beam and repeated conventional

text: spectrophotometric

text: techniques.

text: During the 1970s and 80s, various observations showed that there is not sufficient visible matter in the universe to account for the apparent strength of gravitational forces within and between galaxies. This led to the idea that up to 90% of the matter in the universe is dark matter that does not emit light or interact with normal baryonic matter. In addition, the assumption that the universe is mostly normal matter led to predictions that were strongly inconsistent with observations. In particular, the universe today is far more lumpy and contains far less deuterium than can be accounted for without dark matter. While dark matter has always been controversial, it is inferred by various observations: the anisotropies in the CMB, galaxy cluster velocity dispersions, large-scale structure distributions, gravitational lensing studies, and X-ray measurements of galaxy clusters.

text: During the 1970s and 80s, various observations showed that there is not sufficient visible matter in the universe to account for the apparent strength of gravitational forces within and between galaxies. This led to the idea that up to 90% of the matter in the universe is dark matter that does not emit light or interact with normal

text: baryon

text: ic matter. In addition, the assumption that the universe is mostly normal matter led to predictions that were strongly inconsistent with observations. In particular, the universe today is far more lumpy and contains far less deuterium than can be accounted for without dark matter. While dark matter has always been controversial, it is inferred by various observations: the anisotropies in the CMB,

text: galaxy cluster

text: velocity dispersions, large-scale structure distributions,

text: gravitational lensing

text: studies, and

text: X-ray measurements

text: of galaxy clusters.

text: Sunglasses offer protection against excessive exposure to light, including its visible and invisible components.

text: Both NAD and NADH strongly absorb ultraviolet light because of the adenine. For example, peak absorption of NAD is at a wavelength of 259 nanometers (nm), with an extinction coefficient of 16,900 Mcm. NADH also absorbs at higher wavelengths, with a second peak in UV absorption at 339 nm with an extinction coefficient of 6,220 Mcm. This difference in the ultraviolet absorption spectra between the oxidized and reduced forms of the coenzymes at higher wavelengths makes it simple to measure the conversion of one to another in enzyme assays – by measuring the amount of UV absorption at 340 nm using a spectrophotometer.

text: Both NAD and NADH strongly absorb

text: ultraviolet

text: light because of the adenine. For example, peak absorption of NAD is at a

text: wavelength

text: of 259

text: nanometer

text: s (nm), with an

text: extinction coefficient

text: of 16,900

text: M

text: cm

text: . NADH also absorbs at higher wavelengths, with a second peak in UV absorption at 339 nm with an extinction coefficient of 6,220 Mcm. This difference in the ultraviolet

text: absorption spectra

text: between the oxidized and reduced forms of the coenzymes at higher wavelengths makes it simple to measure the conversion of one to another in

text: enzyme assay

text: s – by measuring the amount of UV absorption at 340 nm using a

text: spectrophotometer

text: The relationships between the energies of the various quantum states are treated by atomic orbital, molecular orbital, and Ligand Field Theory. If photons of a particular wavelength are absorbed by matter, then when we observe light reflected from or transmitted through that matter, what we see is the complementary color, made up of the other visible wavelengths remaining. For example, beta-carotene has maximum absorption at 454 nm (blue light), consequently what visible light remains appears orange .

text: The relationships between the energies of the various quantum states are treated by

text: atomic orbital

text: molecular orbital

text: , and

text: Ligand Field Theory

text: . If photons of a particular wavelength are absorbed by matter, then when we observe light reflected from or transmitted through that matter, what we see is the

text: complementary color

text: , made up of the other visible wavelengths remaining. For example,

text: beta-carotene

text: has maximum absorption at 454 nm (blue light), consequently what visible light remains appears orange .

text: Exposure and focusing are difficult when using UV or IR film with a camera and lens designed for visible light. The ISO standard for film speed only applies to visible light, so visual-spectrum light meters are nearly useless. Film manufacturers can supply suggested equivalent film speeds under different conditions, and recommend heavy bracketing (e.g., with a certain filter, assume ISO 25 under daylight and ISO 64 under tungsten lighting). This allows a light meter to be used to estimate an exposure. The focal point for IR is slightly farther away from the camera than visible light, and UV slightly closer; this must be compensated for when focusing. Apochromatic lenses are sometimes recommended due to their improved focusing across the spectrum.

text: Exposure and focusing are difficult when using UV or IR film with a camera and lens designed for visible light. The ISO standard for film speed only applies to visible light, so visual-spectrum light meters are nearly useless. Film manufacturers can supply suggested equivalent film speeds under different conditions, and recommend heavy

text: bracketing

text: (e.g., with a certain filter, assume ISO 25 under daylight and ISO 64 under tungsten lighting). This allows a light meter to be used to estimate an exposure. The focal point for IR is slightly farther away from the camera than visible light, and UV slightly closer; this must be compensated for when focusing.

text: Apochromat

text: ic lenses are sometimes recommended due to their improved focusing across the spectrum.

text: One particularly important experimental tool in astrochemistry is spectroscopy, the use of telescopes to measure the absorption and emission of light from molecules and atoms in various environments. By comparing astronomical observations with laboratory measurements, astrochemists can infer the elemental abundances, chemical composition, and temperatures of stars and interstellar clouds. This is possible because ions, atoms, and molecules have characteristic spectra: that is, the absorption and emission of certain wavelengths (colors) of light, often not visible to the human eye. However, these measurements have limitations, with various types of radiation (radio, infrared, visible, ultraviolet etc.) able to detect only certain types of species, depending on the chemical properties of the molecules. Interstellar formaldehyde was the first organic molecule detected in the interstellar medium.

text: One particularly important experimental tool in astrochemistry is

text: spectroscopy

text: , the use of

text: telescope

text: s to measure the absorption and emission of

text: light

text: from molecules and atoms in various environments. By comparing astronomical observations with laboratory measurements, astrochemists can infer the elemental abundances, chemical composition, and

text: temperature

text: s of

text: star

text: s and

text: interstellar cloud

text: s. This is possible because

text: ion

text: s,

text: atom

text: s, and molecules have characteristic spectra: that is, the absorption and emission of certain wavelengths (colors) of light, often not visible to the human eye. However, these measurements have limitations, with various types of radiation (

text: radio

text: infrared

text: , visible,

text: ultraviolet

text: etc.) able to detect only certain types of species, depending on the chemical properties of the molecules.

text: Interstellar formaldehyde

text: was the first

text: organic molecule

text: detected in the interstellar medium.

text: In 2010 Sarfatti was among 30 people invited to join a working group, the 100-Year Starship study, financed by the Defense Advanced Research Projects Agency and NASA's Ames Research Center, to discuss how interstellar space flight might be achieved. Sarfatti was invited by Creon Levit of NASA, who told the BBC that Sarfatti is able to discuss unusual ideas without worrying about the effect on his career: "Although his interests and style are outside of the mainstream, he is a fully pedigreed physicist and he knows as much or more than mainstream physicists. When he talks about warp drives, he knows what he's talking about. He knows he's speculating." General Pete Worden, former head of USAF Space Command, was NASA AMES head at the time of this meeting. Worden invited Sarfatti because of his work on exotic propulsion at Joe Firmage's ISSO then headed by Creon Levit on leave from NASA (1999-2000). Sarfatti, conjectured that superconducting meta-materials would slow the effective speed of light for virtual near field photons and gravitons. The coupling of matter to spacetime varies as the inverse fourth power of the effective speed of light. Therefore, the effect of matter on gravity is greatly increased if the speed of light is lowered to almost zero, which has been observed in atomic gas Bose-Einstein condensates. In addition, the near electromagnetic field energy is negative in the meta material. So, Sarfatti conjectured, in his Orlando Starship talk in 2011, that a strong repulsive anti-gravity near field could be generated at low power. https://www.academia.edu/17018493/Low_Power_Warp_DriveCreon Levit was Pete Worden's assistant in 2010.  Sarfatti's ISSO work with Levit is summarized by Greek physicist  Dimitris Hatzopoulos  here"There is current fundamental research work by Jack Sarfatti, Harold Puthoff, Bernard Haisch (calphysics.org), Eric Davis, Mark Pesses, Rueda, Tom Valone, Gennady Shipov, Michio Kaku. Sarfatti in his book "Super Cosmos" (2005) has the most detailed "theory" based on the recent discovery of the repulsive anti-gravity field "dark energy" (of the matter+energy content in the universe, ~73% is made of "dark energy", 23% "cold dark matter" and 4% atoms) that is accelerating the expansion of the 3D space of our universe. Sarfatti also cites Alcubierre's weightless warp drive without time dilation as essential conditions for "propellantless propulsion" in what Puthoff has called "metric engineering." Sarfatti's key idea is that the ship is able to control its own zero-g force geodesic flight path using small amounts of energy. This is controversial of course, but he does have a paper on the physics archive with the mathematics of his theory. Kaku writes of "Type IV" advanced civilization supertechnology that is close to Puthoff's idea of "metric engineering" the fabric of spacetime itself.The mysterious dark energy, which has puzzled astrophysicists, is actually "zero-point vacuum fluctuations with positive energy density and negative quantum pressure. Dark matter is the same, but with negative energy density and positive pressure. Zero-point energy is 96 percent of all the "stuff" in our visible universe. What controls the sign of the zero point energy density at a given place and time and at a given scale of resolution? That is the 64 trillion dollar question, whose solution is the key to the metric engineering of weightless warp drive and star-gate wormholes." http://www.hyper.net/ufo/physics.html In addition"One is proposed by American theoretical physicist Jack Sarfatti. In the 1970s Sarfatti played a key role in game-changing discoveries that transformed quantum physics (mostly through the spooky phenomenon of “quantum entanglement”). His contribution is described in MIT historian David Kaiser’s award-winning book How the Hippies Saved Physics (2011). Central to Sarfatti’s ideas is the notion that time doesn’t flow only in one direction, and that, at least at one direction, and that, at least at the quantum level, the current state of a particle can be influenced by its future state (just as it can be influencing its past state now). In principle, this isn’t as far-out as it might seem, as “retroactive causation” is accepted in some quantum-level phenomena, and at that level time is, in a sense, irrelevant. But Sarfatti has taken things to a whole new level; indeed, a cosmic one. Sarfatti noticed that, in a universe with a “future horizon”, if a new predicted by Stephen Hawking, originally to describe the radiation released by black holes) in the form of gravitational waves were to travel backwards in time from that horizon, it would account for the observed value of dark energy. If this is correct, then dark energy is literally coming back from the future. It’s a bold idea, and strains even most physicists’ notions of reality. But then again so do all attempts at explaining dark energy. Sarfatti’s theory may seem crazy, but in the famous question is whether it’s crazy enough to be true”. And if Sarfatti turns out to be right then his solution to the dark energy problem has enormous implications, especially as it suggests that the future universe is, at some level, shaping its own past."Sinziana Paduroiu (2015-09-14). The Dark Side of the Universe (UneXplained Rapid Reads) (Kindle Locations 267-269). Windmill Books Ltd. Kindle Edition.

text: In 2010 Sarfatti was among 30 people invited to join a working group, the 100-Year Starship study, financed by the

text: Defense Advanced Research Projects Agency

text: and NASA's

text: Ames Research Center

text: , to discuss how

text: interstellar space flight

text: Absorption peaks in the visible light spectrum are measured at 495 and 545/566 nm, depending on the chromophores bound and the considered organism. A strong emission peak exists at 575 ± 10 nm. (i.e., phycoerythrin absorbs slightly blue-green/yellowish light and emits slightly orange-yellow light.)

text: Absorption peak

text: s in the visible light spectrum are measured at 495 and 545/566 nm, depending on the chromophores bound and the considered organism. A strong

text: emission peak

text: exists at 575 ± 10 nm. (i.e., phycoerythrin absorbs slightly blue-green/yellowish light and emits slightly orange-yellow light.)

text: In architecture, light reflectance value (LRV), is a measure of visible and usable light that is reflected from a surface when illuminated by a light source.  The measurement is most commonly used by design professionals, such as architectural color consultants, architects, environmental graphic designers and interior designers.

text: In

text: architecture

text: , light reflectance value (LRV), is a measure of visible and usable light that is

text: reflected

text: from a surface when illuminated by a light source.  The measurement is most commonly used by design professionals, such as architectural

text: color consultants

text: architect

text: s,

text: environmental graphic designers

text: and

text: interior designer

text: s.

text: The chiral pitch, p, refers to the distance over which the LC molecules undergo a full 360° twist (but note that the structure of the chiral nematic phase repeats itself every half-pitch, since in this phase directors at 0° and ±180° are equivalent). The pitch, p, typically changes when the temperature is altered or when other molecules are added to the LC host (an achiral LC host material will form a chiral phase if doped with a chiral material), allowing the pitch of a given material to be tuned accordingly. In some liquid crystal systems, the pitch is of the same order as the wavelength of visible light. This causes these systems to exhibit unique optical properties, such as Bragg reflection and low-threshold laser emission, and these properties are exploited in a number of optical applications. For the case of Bragg reflection only the lowest-order reflection is allowed if the light is incident along the helical axis, whereas for oblique incidence higher-order reflections become permitted. Cholesteric liquid crystals also exhibit the unique property that they reflect circularly polarized light when it is incident along the helical axis and elliptically polarized if it comes in obliquely.

text: The chiral pitch, p, refers to the distance over which the LC molecules undergo a full 360° twist (but note that the structure of the chiral nematic phase repeats itself every half-pitch, since in this phase directors at 0° and ±180° are equivalent). The pitch, p, typically changes when the temperature is altered or when other molecules are added to the LC host (an achiral LC host material will form a chiral phase if doped with a chiral material), allowing the pitch of a given material to be tuned accordingly. In some liquid crystal systems, the pitch is of the same order as the

text: wavelength

text: of

text: visible light

text: . This causes these systems to exhibit unique optical properties, such as Bragg reflection and low-threshold

text: laser

text: emission, and these properties are exploited in a number of optical applications. For the case of Bragg reflection only the lowest-order reflection is allowed if the light is incident along the helical axis, whereas for oblique incidence higher-order reflections become permitted. Cholesteric liquid crystals also exhibit the unique property that they reflect circularly polarized light when it is incident along the helical axis and

text: elliptically polarized

text: if it comes in obliquely.

text: Being a conjugated molecule, oxybenzone absorbs at lower energies than many aromatic molecules. As in related compounds, the hydroxyl group is hydrogen bonded to the ketone. This interaction contributes to oxybenzone's light-absorption properties. At low temperatures, however, it is possible to observe both the phosphorescence and the triplet-triplet absorption spectrum. At 175 K the triplet lifetime is 24 ns. The short lifetime has been attributed to a fast intramolecular hydrogen transfer between the oxygen of the C=O and the OH.

text: Being a

text: conjugated

text: molecule, oxybenzone absorbs at lower energies than many aromatic molecules. As in related compounds, the

text: hydroxyl

text: group is hydrogen bonded to the ketone. This interaction contributes to oxybenzone's light-absorption properties. At low temperatures, however, it is possible to observe both the

text: phosphorescence

text: and the triplet-triplet absorption spectrum. At 175 K the triplet lifetime is 24 ns. The short lifetime has been attributed to a fast intramolecular hydrogen transfer between the oxygen of the C=O and the OH.

text: Electrochromic devices change light transmission properties in response to voltage and thus allow control over the amount of light and heat passing through. In electrochromic windows, the electrochromic material changes its opacity: it changes between a colored, translucent state (usually blue) and a transparent state. A burst of electricity is required for changing its opacity, but once the change has been effected, no electricity is needed for maintaining the particular shade which has been reached. Darkening occurs from the edges, moving inward, and is a slow process, ranging from many seconds to several minutes depending on window size. Electrochromic glass provides visibility even in the darkened state and thus preserves visible contact with the outside environment. It has been used in small-scale applications such as rearview mirrors. Electrochromic technology also finds use in indoor applications, for example, for protection of objects under the glass of museum display cases and picture frame glass from the damaging effects of the UV and visible wavelengths of artificial light.

text: Electrochromic

text: devices change light transmission properties in response to voltage and thus allow control over the amount of light and heat passing through. In electrochromic windows, the electrochromic material changes its

text: opacity

text: : it changes between a colored,

text: translucent

text: state (usually blue) and a

text: transparent

text: state. A burst of electricity is required for changing its opacity, but once the change has been effected, no electricity is needed for maintaining the particular shade which has been reached. Darkening occurs from the edges, moving inward, and is a slow process, ranging from many seconds to several minutes depending on window size. Electrochromic glass provides visibility even in the darkened state and thus preserves visible contact with the outside environment. It has been used in small-scale applications such as rearview mirrors. Electrochromic technology also finds use in indoor applications, for example, for protection of objects under the glass of museum display cases and picture frame glass from the damaging effects of the UV and visible wavelengths of artificial light.

text: The stadium lighting are composed with 16 light posts, allocated to the interior of the deck. Which makes it suitable for High Definition transmissions. The frontage of the stadium have changing lights for decorative ilumination.

text: The stadium lighting are composed with 16 light posts, allocated to the interior of the deck. Which makes it suitable for

text: High Definition

text: transmissions. The frontage of the stadium have changing lights for decorative ilumination.

text: X-ray absorption spectroscopy (XAS) is used to study the coordination structure of atoms in materials and molecules. The synchrotron beam energy is tuned through the absorption edge of an element of interest, and modulations in the absorption are measured. Photoelectron transitions cause modulations near the absorption edge, and analysis of these modulations (called the X-ray absorption near-edge structure (XANES) or near-edge X-ray absorption fine structure (NEXAFS)) reveals information about the chemical state and local symmetry of that element. At incident beam energies which are much higher than the absorption edge, photoelectron scattering causes "ringing" modulations called the extended X-ray absorption fine structure (EXAFS). Fourier transformation of the EXAFS regime yields the bond lengths and number of the surrounding the absorbing atom; it is therefore useful for studying liquids and amorphous materials as well as sparse species such as impurities. A related technique, X-ray magnetic circular dichroism (XMCD), uses circularly polarized X-rays to measure the magnetic properties of an element.

text: X-ray absorption spectroscopy

text: (XAS) is used to study the coordination structure of atoms in materials and molecules. The synchrotron beam energy is tuned through the absorption edge of an element of interest, and modulations in the absorption are measured.

text: Photoelectron

text: transitions cause modulations near the absorption edge, and analysis of these modulations (called the

text: X-ray absorption near-edge structure

text: (XANES) or

text: near-edge X-ray absorption fine structure

text: (NEXAFS)) reveals information about the

text: chemical state

text: and local symmetry of that element. At incident beam energies which are much higher than the absorption edge, photoelectron scattering causes "ringing" modulations called the

entity_name: Extended X-ray absorption fine structure

text: extended X-ray absorption fine structure

text: (EXAFS).

text: Fourier transformation

text: of the EXAFS regime yields the bond lengths and number of the surrounding the absorbing atom; it is therefore useful for studying liquids and

text: amorphous

text: materials as well as sparse species such as impurities. A related technique,

text: X-ray magnetic circular dichroism

text: (XMCD), uses circularly polarized X-rays to measure the magnetic properties of an element.

text: Absorption is a disposition or personality trait in which a person becomes absorbed in his or her mental imagery, particularly fantasy. The original research on absorption was by American psychologist Auke Tellegen. Roche reports that fantasy proneness and absorption are highly correlated. Fantasizers become absorbed within their vivid and realistic mental imagery.

text: Absorption

text: is a disposition or personality trait in which a person becomes absorbed in his or her mental imagery, particularly fantasy. The original research on absorption was by American psychologist Auke Tellegen. Roche reports that fantasy proneness and absorption are highly correlated. Fantasizers become absorbed within their vivid and realistic mental imagery.

text: Highway 27, the Stuart Lake Highway, is a 53 km (33 mi) long spur of the Yellowhead Highway in the Regional District of Bulkley-Nechako. First opened in 1967, it provides a connection from Vanderhoof, on Highway 16, north to Fort St. James, at the southern end of Stuart Lake. Highway 27 is an excellent two lane all weather roadway, well maintained by BC government overseen contractors. Major hazards are moose and deer that frequently run in front of oncoming vehicles. Persons driving this roadway at night should be cautious and slow down some.Moose can be difficult to see until too late since their fur tends to absorb light and the eyes don't reflect light well.  The most visible portion of a moose is from the knee joints down on all four legs which are normally whiter. The expression used by most truckers in the area is "watch for the white" referring to the white on the legs since that is all that seems to reflect light from head lamps.

text: Highway 27, the Stuart Lake Highway, is a 53 km (33 mi) long spur of the

text: Yellowhead Highway

text: in the

text: Regional District of Bulkley-Nechako

text: . First opened in 1967, it provides a connection from

text: Vanderhoof

text: , on

text: Highway 16

text: , north to

text: Fort St. James

text: , at the southern end of

text: Stuart Lake

text: . Highway 27 is an excellent two lane all weather roadway, well maintained by BC government overseen contractors. Major hazards are moose and deer that frequently run in front of oncoming vehicles. Persons driving this roadway at night should be cautious and slow down some.Moose can be difficult to see until too late since their fur tends to absorb light and the eyes don't reflect light well.  The most visible portion of a moose is from the knee joints down on all four legs which are normally whiter. The expression used by most truckers in the area is "watch for the white" referring to the white on the legs since that is all that seems to reflect light from

text: head lamp

text: s.

text: At 10:00 pm, they radioed the station agent at Auburn/Lewiston Municipal Airport for the latest weather. The agent reported a 300' obscured, indefinite ceiling, visibility of  in light drizzle, wind 020° (north-northeast) at 4 knots, altimeter 30.24 InHg. Shortly after this, the crew was advised by a controller in Portland that they were drifting east of the ILS approach course to runway 4 at Auburn. He advised them to turn to heading 340 to intercept. The captain responded "OK". Almost a minute later, the controller advised them they were passing the Lewie NDB beacon at the outer marker for the approach and asked if they were receiving it. The first officer responded "affirmative". The controller then cleared them to switch to the airport's frequency, which was acknowledged by the first officer. This was the last transmission received from the flight. Portland controllers were notified less than 10 minutes later that the plane had crashed at 10:05 pm.

text: At 10:00 pm, they radioed the station agent at Auburn/Lewiston Municipal Airport for the latest weather. The agent reported a 300' obscured, indefinite ceiling, visibility of  in light drizzle, wind 020° (north-northeast) at 4

text: knots

text: , altimeter 30.24

text: InHg

text: . Shortly after this, the crew was advised by a controller in

text: Portland

text: that they were drifting east of the

text: ILS

text: approach course to runway 4 at Auburn. He advised them to turn to heading 340 to intercept. The captain responded "OK". Almost a minute later, the controller advised them they were passing the Lewie

text: NDB

text: beacon at the outer marker for the approach and asked if they were receiving it. The first officer responded "affirmative". The controller then cleared them to switch to the airport's frequency, which was acknowledged by the first officer. This was the last transmission received from the flight. Portland controllers were notified less than 10 minutes later that the plane had crashed at 10:05 pm.

text: In addition to visible light, specular reflection can be observed in the ionospheric reflection of radiowaves and the reflection of radio- or microwave radar signals by flying objects. The measurement technique of x-ray reflectivity exploits specular reflectivity to study thin films and interfaces with sub-nanometer resolution, using either modern laboratory sources or synchrotron x-rays.

text: In addition to

text: visible light

text: , specular reflection can be observed in the

text: ionospheric reflection

text: of

text: radiowave

text: s and the reflection of radio- or

text: microwave

text: radar

text: signals by flying objects. The measurement technique of

text: x-ray reflectivity

text: exploits specular reflectivity to study thin films and interfaces with sub-nanometer resolution, using either modern laboratory sources or

text: synchrotron

text: x-rays.

text: A visibility reduction is probably the most apparent symptom of air pollution.  Visibility degradation is caused by the absorption and scattering of light by particles and gases in the atmosphere. Absorption of electromagnetic radiation by gases and particles is sometimes the cause of discolorations in the atmosphere but usually does not contribute very significantly to visibility degradation.

text: A visibility reduction is probably the most apparent symptom of

text: air pollution

text: .  Visibility degradation is caused by the

text: absorption

text: and

text: scattering

text: of light by particles and gases in the

text: atmosphere

text: . Absorption of

text: electromagnetic radiation

text: by gases and particles is sometimes the cause of discolorations in the atmosphere but usually does not contribute very significantly to visibility degradation.

text: Infrared is used in night vision equipment when there is insufficient visible light to see. Night vision devices operate through a process involving the conversion of ambient light photons into electrons that are then amplified by a chemical and electrical process and then converted back into visible light. Infrared light sources can be used to augment the available ambient light for conversion by night vision devices, increasing in-the-dark visibility without actually using a visible light source.

text: Infrared is used in night vision equipment when there is insufficient

text: visible light

text: to see.

text: Night vision devices

text: operate through a process involving the conversion of ambient light photons into electrons that are then amplified by a chemical and electrical process and then converted back into visible light. Infrared light sources can be used to augment the available ambient light for conversion by night vision devices, increasing in-the-dark visibility without actually using a visible light source.

text: Atomic line filters may operate in the ultraviolet, visible and infrared regions of the electromagnetic spectrum. In absorption-re-emission ALFs, the frequency of light must be shifted in order for the filter to operate, and in a passive device, this shift must be to a lower frequency (i.e. red shifted) simply because of energy conservation. This means that passive filters are rarely able to work with infrared light, because the output frequency would be impractically low. If photomultiplier tubes (PMTs) are used then the "output wavelength of the ARF should lie in a spectral region in which commercial, large-area, long-lived PMT's [sic] possess maximum sensitivity". In such a case, active ALFs would have the advantage over passive ALFs as they would more readily, "generate output wavelengths in the near UV, the spectral region in which well-developed photocathodes possess their highest sensitivity".

text: Atomic line filters may operate in the

text: ultraviolet

text: visible

text: and infrared regions of the

text: electromagnetic spectrum

text: . In absorption-re-emission ALFs, the frequency of light must be shifted in order for the filter to operate, and in a passive device, this shift must be to a lower frequency (i.e. red shifted) simply because of energy conservation. This means that passive filters are rarely able to work with infrared light, because the output frequency would be impractically low. If

text: photomultiplier tubes

text: (PMTs) are used then the "output wavelength of the ARF should lie in a spectral region in which commercial, large-area, long-lived PMT's [sic] possess maximum sensitivity". In such a case, active ALFs would have the advantage over passive ALFs as they would more readily, "generate output wavelengths in the near UV, the spectral region in which well-developed

text: photocathode

text: s possess their highest sensitivity".

text: Physical absorption or non-reactive absorption is made between two phases of matter: a liquid absorbs a gas, or a solid absorbs a liquid.

text: A galaxy rotation curve is a plot of the orbital velocities (i.e., the speeds) of visible stars or gas in that galaxy versus their radial distance from that galaxy's center. The rotational/orbital speed of galaxies/stars does not decline with distance, unlike other orbital systems such as stars/planets and planets/moons that also have most of their mass at the centre. In the latter cases, this reflects the mass distributions within those systems. The mass observations for galaxies based on the light that they emit are far too low to explain the velocity observations. The dark matter hypothesis accounts for the missing mass, explaining the anomaly.

text: A galaxy rotation curve is a plot of the orbital velocities (i.e., the speeds) of visible

text: star

text: s or gas in that galaxy versus their

text: radial distance

text: from that galaxy's center. The rotational/orbital speed of galaxies/stars does not decline with distance, unlike other orbital systems such as stars/planets and planets/moons that also have most of their mass at the centre. In the latter cases, this reflects the mass distributions within those systems. The mass observations for galaxies based on the light that they emit are far too low to explain the velocity observations. The dark matter hypothesis accounts for the missing mass, explaining the anomaly.

text: When a longitudinal sound wave strikes a flat surface, sound is reflected in a coherent manner provided that the dimension of the reflective surface is large compared to the wavelength of the sound. Note that audible sound has a very wide frequency range (from 20 to about 17000 Hz), and thus a very wide range of wavelengths (from about 20 mm to 17 m). As a result, the overall nature of the reflection varies according to the texture and structure of the surface. For example, porous materials will absorb some energy, and rough materials (where rough is relative to the wavelength) tend to reflect in many directions—to scatter the energy, rather than to reflect it coherently. This leads into the field of architectural acoustics, because the nature of these reflections is critical to the auditory feel of a space. In the theory of exterior noise mitigation, reflective surface size mildly detracts from the concept of a noise barrier by reflecting some of the sound into the opposite direction.

text: When a longitudinal

text: sound wave

text: strikes a flat surface, sound is reflected in a coherent manner provided that the dimension of the reflective surface is large compared to the wavelength of the sound. Note that audible sound has a very wide frequency range (from 20 to about 17000 Hz), and thus a very wide range of wavelengths (from about 20 mm to 17 m). As a result, the overall nature of the reflection varies according to the texture and structure of the surface. For example, porous materials will absorb some energy, and rough materials (where rough is relative to the wavelength) tend to reflect in many directions—to scatter the energy, rather than to reflect it coherently. This leads into the field of

text: architectural acoustics

text: , because the nature of these reflections is critical to the auditory feel of a space. In the theory of exterior

text: noise mitigation

text: , reflective surface size mildly detracts from the concept of a

text: noise barrier

text: by reflecting some of the sound into the opposite direction.

text: SNR 0509-67.5 is a remnant from a supernova in the Large Magellanic Cloud (LMC), that is 160,000 light years away in the constellation Dorado. It was probably a type Ia supernova, as indicated by the detection in 2004 of the elements silicon and iron. Any surviving stars have not moved far from the site of the explosion. The supernova occurred about 400 years delayed in Earth's time frame. However, researchers at the Space Telescope Science Institute in Baltimore, Md. have identified light from the supernova that was reflected off of interstellar dust, delaying its arrival at Earth by 400 years. This delay, called a light echo of the supernova explosion also allowed the astronomers to measure the spectral signature of the light from the explosion. By virtue of the color signature, astronomers were able to deduce it was a Type Ia supernova. Scientists have also observed the supernova remnant at X-ray and visible wavelengths, and studied a light echo that helps assess the energy involved in this unusually energetic supernova.

text: SNR 0509-67.5 is a remnant from a

text: supernova

text: in the

text: Large Magellanic Cloud

text: (LMC), that is 160,000

text: light years

text: away in the constellation

text: Dorado

text: . It was probably a

text: type Ia supernova

text: , as indicated by the detection in 2004 of the

text: elements

text: silicon

text: and

text: iron

text: . Any surviving stars have not moved far from the site of the explosion. The supernova occurred about 400 years delayed in Earth's time frame. However, researchers at the Space Telescope Science Institute in Baltimore, Md. have identified light from the supernova that was reflected off of interstellar dust, delaying its arrival at Earth by 400 years. This delay, called a light echo of the supernova explosion also allowed the astronomers to measure the spectral signature of the light from the explosion. By virtue of the color signature, astronomers were able to deduce it was a Type Ia supernova. Scientists have also observed the supernova remnant at

text: X-ray

text: and

text: visible

text: wavelengths, and studied a

text: light echo

text: that helps assess the energy involved in this unusually energetic supernova.

text: A simple linear polarizer can be made by tilting a stack of glass plates at Brewster's angle to the beam.   Some of the s-polarized light is reflected from each surface of each plate. For a stack of plates, each reflection depletes the incident beam of s-polarized light, leaving a greater fraction of p-polarized light in the transmitted beam at each stage. For visible light in air and typical glass, Brewster's angle is about 57°, and about 16% of the s-polarized light present in the beam is reflected for each air-to-glass or glass-to-air transition. It takes many plates to achieve even mediocre polarization of the transmitted beam with this approach. For a stack of 10 plates (20 reflections), about 3% (= (1-0.16)) of the s-polarized light is transmitted. The reflected beam, while fully polarized, is spread out and may not be very useful.

text: Automatic transmissions are easy to use. However, in the past, automatic transmissions of this type have had a number of problems; they were complex and expensive, sometimes had reliability problems (which sometimes caused more expenses in repair), have often been less fuel-efficient than their manual counterparts (due to "slippage" in the torque converter), and their shift time was slower than a manual making them uncompetitive for racing. With the advancement of modern automatic transmissions this has changed.

text: Automatic transmissions are easy to use. However, in the past, automatic transmissions of this type have had a number of problems; they were complex and expensive, sometimes had reliability problems (which sometimes caused more expenses in repair), have often been less fuel-efficient than their manual counterparts (due to "slippage" in the torque converter), and their

text: shift time

text: was slower than a manual making them uncompetitive for racing. With the advancement of modern automatic transmissions this has changed.

text: Dark matter cannot be seen because it does not shine or reflect light. Astronomers can only detect its influence by how its gravity affects light. By mapping the distorted light created by gravitational lensing, astronomers can trace how dark matter is distributed in the cluster. While mapping the dark matter, astronomers found a dark-matter ring near the cluster's center (although this is disputed by other independent studies). The ring's discovery is among the strongest evidence that dark matter exists.

text: The intrinsic color of liquid water may be demonstrated by looking at a white light source through a long pipe that is filled with purified water and closed at both ends with a transparent window. The light turquoise blue color is caused by weak absorption in the red part of the visible spectrum.

text: The intrinsic color of liquid water may be demonstrated by looking at a white light source through a long pipe that is filled with purified water and closed at both ends with a transparent window. The light

text: turquoise

text: blue color is caused by weak

text: absorption

text: in the red part of the

text: visible spectrum

text: Retroreflective sheeting is flexible retroreflective material primarily used to increase the nighttime conspicuity of traffic signs, high-visibility clothing, and other items so they are safely and effectively visible in the light of an approaching driver's headlamps. They are also used as a material to increase the scanning range of barcodes in factory settings. The sheeting consists of retroreflective glass beads, microprisms, or encapsulated lenses sealed onto a fabric or plastic substrate. Many different colors and degrees of reflection intensity are provided by numerous manufacturers for various applications. As with any retroreflector, sheeting glows brightly when there is a small angle between the observer's eye and the light source directed toward the sheeting, but appears nonreflective when viewed from other directions.

text: Retroreflective sheeting is flexible

text: retroreflective

text: material primarily used to increase the nighttime

text: conspicuity

text: of

text: traffic sign

text: s,

text: high-visibility clothing

text: , and other items so they are safely and effectively visible in the light of an approaching driver's

text: headlamp

text: s. They are also used as a material to increase the scanning range of barcodes in factory settings. The sheeting consists of retroreflective glass beads, microprisms, or encapsulated lenses sealed onto a fabric or plastic substrate. Many different colors and degrees of reflection intensity are provided by numerous manufacturers for various applications. As with any retroreflector, sheeting glows brightly when there is a small angle between the observer's eye and the light source directed toward the sheeting, but appears nonreflective when viewed from other directions.

text: The earliest form of a manual transmission is thought to have been invented by Louis-René Panhard and Émile Levassor in the late 19th century. This type of transmission offered multiple gear ratios and, in most cases, reverse. The gears were typically engaged by sliding them on their shafts (hence the phrase shifting gears), which required careful timing and throttle manipulation when shifting, so the gears would be spinning at roughly the same speed when engaged; otherwise, the teeth would refuse to mesh. These transmissions are called sliding mesh transmissions or sometimes crash boxes, because of the difficulty in changing gears and the loud grinding sound that often accompanied. Newer manual transmissions on cars have all gears mesh at all times and are referred to as constant-mesh transmissions, with "synchro-mesh" being a further refinement of the constant mesh principle.

text: The earliest form of a manual transmission is thought to have been invented by

text: Louis-René Panhard

text: and

text: Émile Levassor

text: in the late 19th century. This type of transmission offered multiple gear ratios and, in most cases, reverse. The gears were typically engaged by sliding them on their shafts (hence the phrase shifting gears), which required careful timing and

text: throttle

text: manipulation when shifting, so the gears would be spinning at roughly the same speed when engaged; otherwise, the teeth would refuse to mesh. These transmissions are called sliding mesh transmissions or sometimes

text: crash boxes

text: , because of the difficulty in changing gears and the loud grinding sound that often accompanied. Newer manual transmissions on cars have all gears mesh at all times and are referred to as constant-mesh transmissions, with "synchro-mesh" being a further refinement of the constant mesh principle.

text: In visible light, this object is neutral or slightly red in color and has a flat, featureless reflectance spectrum.

text: Materials which do not allow the transmission of any light wave frequencies are called opaque. Such substances may have a chemical composition which includes what are referred to as absorption centers. Most materials are composed of materials which are selective in their absorption of light frequencies. Thus they absorb only certain portions of the visible spectrum. The frequencies of the spectrum which are not absorbed are either reflected back or transmitted for our physical observation. In the visible portion of the spectrum, this is what gives rise to color.

text: Materials which do not allow the transmission of any light wave frequencies are called

text: opaque

text: . Such substances may have a chemical composition which includes what are referred to as absorption centers. Most materials are composed of materials which are selective in their absorption of light frequencies. Thus they absorb only certain portions of the visible spectrum. The frequencies of the spectrum which are not absorbed are either reflected back or transmitted for our physical observation. In the visible portion of the spectrum, this is what gives rise to color.

text: The Kapitsa–Dirac effect causes beams of particles to diffract as the result of meeting a standing wave of light. Light can be used to position matter using various phenomena (see optical tweezers).

text: The

text: Kapitsa–Dirac effect

text: causes beams of particles to diffract as the result of meeting a standing wave of light. Light can be used to position matter using various phenomena (see

text: optical tweezers

text: One of the main needs for a transmission is to match the speed of the engine to the speed of the locomotive, so that the engine can work in its useful operating speed range. All locomotives need to deliver high torque from zero rail speed for startup. The overall range of gear ratios required from the transmission thus depends on the maximum speed of the train. The narrower the power band of the engine, the more precise control of gearbox ratio is required, either by using a continuously variable transmission or a discrete ratio transmission with more ratios.

text: One of the main needs for a transmission is to match the speed of the engine to the speed of the locomotive, so that the engine can work in its useful operating speed range. All locomotives need to deliver high torque from zero rail speed for startup. The overall range of gear ratios required from the transmission thus depends on the maximum speed of the train. The narrower the power band of the engine, the more precise control of gearbox ratio is required, either by using a

text: continuously variable transmission

text: or a discrete ratio transmission with more ratios.

text: Although water is nearly transparent in the range of visible light, it becomes absorbing over the near-infrared region. Water is a critical component since its concentration is high in human tissue. The absorption spectrum of water in the range from 250 to 1000 nm is shown in Figure 2. Although absorption is rather low in this spectral range, it still contributes to the overall attenuation of tissue.

text: : intensity of light after absorption;

text: : intensity of light after absorption;

text: Fluorescent black light tubes are typically made in the same fashion as normal fluorescent tubes except that a phosphor that emits UVA light instead of visible white light is used.  The type most commonly used for black lights, designated blacklight blue or "BLB" by the industry, has a dark blue filter coating on the tube, which filters out most visible light, so that fluorescence effects can be observed.  These tubes have a dim violet glow when operating.  They should not be confused with "blacklight" or "BL" tubes, which have no filter coating, and have a brighter blue color.  These are made for use in "bug zapper" insect traps, where visible light emission is not a problem.   The phosphor typically used for a near 368 to 371 nanometer emission peak is either europium-doped strontium fluoroborate (:) or europium-doped strontium borate (:) while the phosphor used to produce a peak around 350 to 353 nanometres is lead-doped barium silicate (:). "Blacklight Blue" lamps peak at 365 nm.

text: Fluorescent black light tubes are typically made in the same fashion as normal

text: fluorescent tube

text: s except that a

text: phosphor

text: that emits UVA light instead of visible white light is used.  The type most commonly used for black lights, designated blacklight blue or "BLB" by the industry, has a dark blue filter coating on the tube, which filters out most visible light, so that

text: fluorescence

text: effects can be observed.  These tubes have a dim violet glow when operating.  They should not be confused with "blacklight" or "BL" tubes, which have no filter coating, and have a brighter blue color.  These are made for use in "

text: bug zapper

text: " insect traps, where visible light emission is not a problem.   The phosphor typically used for a near 368 to 371 nanometer emission peak is either

text: europium

text: -doped strontium fluoroborate (:) or europium-doped strontium borate (:) while the phosphor used to produce a peak around 350 to 353 nanometres is lead-doped barium silicate (:). "Blacklight Blue" lamps peak at 365 nm.

text: In 1574, Taqi al-Din (1526–1585) wrote the last major Arabic work on optics, entitled Kitab Nūr hadaqat al-ibsār wa-nūr haqīqat al-anzār (Book of the Light of the Pupil of Vision and the Light of the Truth of the Sights), which contains experimental investigations in three volumes on vision, the light's reflection, and the light's refraction. The book deals with the structure of light, its diffusion and global refraction, and the relation between light and colour. In the first volume, he discusses "the nature of light, the source of light, the nature of the propagation of light, the formation of sight, and the effect of light on the eye and sight". In the second volume, he provides "experimental proof of the specular reflection of accidental as well as essential light, a complete formulation of the laws of reflection, and a description of the construction and use of a copper instrument for measuring reflections from plane, spherical, cylindrical, and conical mirrors, whether convex or concave." The third volume "analyses the important question of the variations light undergoes while traveling in mediums having different densities, i.e. the nature of refracted light, the formation of refraction, the nature of images formed by refracted light."

text: In 1574,

text: Taqi al-Din

text: (1526–1585) wrote the last major

text: Arabic work on optics

text: , entitled Kitab Nūr hadaqat al-ibsār wa-nūr haqīqat al-anzār (Book of the Light of the Pupil of Vision and the Light of the Truth of the Sights), which contains

text: experiment

text: al investigations in three volumes on

text: vision

text: , the

text: light

text: 's

text: reflection

text: , and the light's

text: refraction

text: . The book deals with the structure of light, its

text: diffusion

text: and global refraction, and the relation between light and

text: colour

text: . In the first volume, he discusses "the nature of light, the source of light, the nature of the propagation of light, the formation of sight, and the effect of light on the eye and sight". In the second volume, he provides "experimental proof of the

text: specular reflection

text: of accidental as well as essential light, a complete formulation of the laws of reflection, and a description of the construction and use of a copper instrument for measuring reflections from

text: plane

text: spherical, cylindrical

text: , and conical

text: mirror

text: s, whether convex or concave." The third volume "analyses the important question of the variations light undergoes while traveling in

text: mediums

text: having different

text: densities

text: , i.e. the nature of refracted light, the formation of refraction, the nature of images formed by refracted light."

text: Shortly after the publication of Report #3, NASA began posting elements for a variety of visible and other well known objects in their periodic NASA Prediction Bulletins, which consisted of the transmission format data in printed form. After trying for some time to convince NASA to release these in electronic form, Ted Kelso took matters into his own hands and began manually copying the listings into text files which he distributed through his CelesTrak bulletin board system. This revealed a problem in NASA's checksum system, which traced back to the lack of the plus character (+) on the teletype machines used at NASA, which ultimately turned out to be a problem from the punch card era that occurred when NORAD updated from the BCD to EBCDIC character set on the computer sending out the updates. This problem went away when Kelso began to receive data directly from NORAD in 1989.

text: Shortly after the publication of Report #3, NASA began posting elements for a variety of visible and other well known objects in their periodic NASA Prediction Bulletins, which consisted of the transmission format data in printed form. After trying for some time to convince NASA to release these in electronic form, Ted Kelso took matters into his own hands and began manually copying the listings into text files which he distributed through his CelesTrak

text: bulletin board system

text: . This revealed a problem in NASA's

text: checksum

text: system, which traced back to the lack of the plus character (+) on the

text: teletype

text: machines used at NASA, which ultimately turned out to be a problem from the punch card era that occurred when NORAD updated from the BCD to

text: EBCDIC

text: character set

text: on the computer sending out the updates. This problem went away when Kelso began to receive data directly from NORAD in 1989.

text: of the Milky Way—its integrated luminosity is about  times that of the Sun (absolute visible magnitude of about −4.1), which is much lower than the luminosity of the majority of globular clusters. However, its mass is about 1.2 million solar masses, which means that galaxy's mass to light ratio is around 450. A high mass to light ratio implies that Com is dominated by the dark matter.

text: of the

text: Milky Way

text: —its integrated

text: luminosity

text: is about  times that of the Sun (absolute

text: visible magnitude

text: of about −4.1), which is much lower than the luminosity of the majority of

text: globular cluster

text: s. However, its mass is about 1.2 million

text: solar mass

text: es, which means that galaxy's

text: mass to light ratio

text: is around 450. A high mass to light ratio implies that Com is dominated by the

text: dark matter

text: The reflectivity of Au, Ag, Al is shown on the figure to the right. The human eye sees electromagnetic radiation with a wavelength near 600 nm as yellow. As is clear from its reflectance spectrum, gold appears yellow because it absorbs blue light more than it absorbs other visible wavelengths of light; the reflected light (which is what we see) is therefore lacking in blue compared to the incident light. Since yellow is complementary to blue, this makes a piece of gold appear yellow (under white light) to human eyes.

text: The

text: reflectivity

text: of Au, Ag, Al is shown on the figure to the right. The human eye sees electromagnetic radiation with a wavelength near 600 nm as yellow. As is clear from its reflectance spectrum, gold appears yellow because it

text: absorbs

text: blue light more than it absorbs other visible wavelengths of light; the reflected light (which is what we see) is therefore lacking in blue compared to the incident light. Since yellow is

text: complementary

text: to blue, this makes a piece of gold appear yellow (under white light) to human eyes.

text: Stephen Thomas Erlewine from AllMusic, Kevin C. Johnson from St. Louis Post-Dispatch and Chris Gernard from Metro Weekly, all of them highlighted "Nothing Really Matters" as one of Ray of Lights best tracks. Erlewine, who also wrote Madonna's biography for the website, highlighted the song as one of Madonna's career stand outs. Chuck Taylor from Billboard labeled the song as a "gem" and commended the "irresistible hook". From the same publication, the Billboard Staff commented, "What if the suave dance of 'Nothing Really Matters', the eye-popping 'Ray of Light' music video or the stark beauty of 'Frozen' never existed? Luckily, we never need to find out." Rolling Stone said that "[s]ongs like the title track and 'Nothing Really Matters' are filled with warmth and wonder." Stephen Thompson from The A.V. Club was positive in his review, stating that the "chugging" chorus and composition "should ring across dance floors for years to come..." Nathan Smith from Houston Press was also positive, stating "Few singles illustrated [Madonna's change in musical approach] better than 'Nothing Really Matters'". He concluded "It's a great, bouncy dance track that never received the love it deserved, and its family-friendly themes are a good fit for the event."

text: Stephen Thomas Erlewine

text: from

text: AllMusic

text: , Kevin C. Johnson from

text: St. Louis Post-Dispatch

text: and Chris Gernard from

text: Metro Weekly

text: , all of them highlighted "Nothing Really Matters" as one of Ray of Lights best tracks. Erlewine, who also wrote Madonna's biography for the website, highlighted the song as one of Madonna's career stand outs. Chuck Taylor from Billboard labeled the song as a "gem" and commended the "irresistible hook". From the same publication, the Billboard Staff commented, "What if the suave dance of 'Nothing Really Matters', the eye-popping 'Ray of Light' music video or the stark beauty of 'Frozen' never existed? Luckily, we never need to find out."

text: Rolling Stone

text: said that "[s]ongs like the title track and 'Nothing Really Matters' are filled with warmth and wonder." Stephen Thompson from

text: The A.V. Club

text: was positive in his review, stating that the "chugging" chorus and composition "should ring across dance floors for years to come..." Nathan Smith from

text: Houston Press

text: was also positive, stating "Few singles illustrated [Madonna's change in musical approach] better than 'Nothing Really Matters'". He concluded "It's a great, bouncy dance track that never received the love it deserved, and its family-friendly themes are a good fit for the event."

text: "Burn the Bright Lights" was written by Christian Nilsson, Justin Gray and Zac Poor, and produced by the latter two with Adrian Breakspear and Gary Pinto. It was mixed by Miles Walker and mastered by Leon Zervos. Amit Ofir provided the guitar for the song. "Burn the Bright Lights" is The Collective's first release without member Zach Russell, who left the band to become a firefighter. According to the Australian Musician Network, "'Burn the Bright Lights' is a song that manifests their passion, drive and desire to succeed." When The Collective heard a demo of the song, they immediately wanted to record it. Julian De Vizio stated that the song has "a power and emotion inside" it "that everyone can relate to no matter what they're going through", while Trent Bell described "Burn the Bright Lights" as "a mature song" that "has got feeling and hits people's hearts."

text: "Burn the Bright Lights" was written by Christian Nilsson, Justin Gray and

text: Zac Poor

text: , and produced by the latter two with Adrian Breakspear and

text: Gary Pinto

text: . It was

text: mixed

text: by Miles Walker and

text: mastered

text: by Leon Zervos. Amit Ofir provided the

text: guitar

text: for the song. "Burn the Bright Lights" is The Collective's first release without member

text: Zach Russell

text: , who left the band to become a firefighter. According to the Australian Musician Network, "'Burn the Bright Lights' is a song that manifests their passion, drive and desire to succeed." When The Collective heard a

text: demo

text: of the song, they immediately wanted to record it.

text: Julian De Vizio

text: stated that the song has "a power and emotion inside" it "that everyone can relate to no matter what they're going through", while

text: Trent Bell

text: described "Burn the Bright Lights" as "a mature song" that "has got feeling and hits people's hearts."

text: The combined absorption spectra of the gases in the atmosphere leave "windows" of low opacity, allowing the transmission of only certain bands of light. The optical window runs from around 300 nm (ultraviolet-C) up into the range humans can see, the visible spectrum (commonly called light), at roughly 400–700 nm and continues to the infrared to around 1100 nm. There are also infrared and radio windows that transmit some infrared and radio waves at longer wavelengths. For example, the radio window runs from about one centimeter to about eleven-meter waves.

text: The combined

text: absorption spectra

text: of the gases in the atmosphere leave "windows" of low

text: opacity

text: , allowing the transmission of only certain bands of light. The

text: optical window

text: runs from around 300 nm (

text: ultraviolet

text: -C) up into the range humans can see, the

text: visible spectrum

text: (commonly called

text: light

text: ), at roughly 400–700 nm and continues to the

text: infrared

text: to around 1100 nm. There are also

text: infrared

text: and

text: radio window

text: s that transmit some infrared and

text: radio waves

text: at longer wavelengths. For example, the radio window runs from about one centimeter to about eleven-meter waves.

text: The transparency of its wings results from the combination of three properties: first, from the low absorption of the visible light by the material constituting its wings, second, from the low scattering of the light passing through the wings and finally, from the low reflection of the light impinging on the wings surface.

text: The transparency of its wings results from the combination of three properties: first, from the low

text: absorption

text: of the visible light by the material constituting its wings, second, from the low

text: scattering of the light

text: passing through the wings and finally, from the low

text: reflection

text: of the light impinging on the wings surface.

text: Materials can transmit (e.g. glass) or reflect (e.g. metals) visible light.

text: Materials can

text: transmit

text: (e.g. glass) or reflect (e.g. metals) visible light.

text: As wavelengths become longer, it becomes easier to use antenna technology to interact with electromagnetic radiation (although it is possible to make very tiny antenna). The near-infrared can be collected much like visible light, however in the far-infrared and submillimetre range,  telescopes can operate more like a radio telescope. For example, the James Clerk Maxwell Telescope observes from wavelengths from 3 μm (0.003 mm) to 2000 μm (2 mm), but uses a parabolic aluminum antenna. On the other hand, the Spitzer Space Telescope, observing from about 3 μm (0.003 mm) to 180 μm (0.18 mm) uses a mirror (reflecting optics). Also using reflecting optics, the Hubble Space Telescope with Wide Field Camera 3 can observe in the frequency range from about 0.2 μm (0.0002 mm) to 1.7 μm (0.0017 mm) (from ultra-violet to infrared light).

text: As wavelengths become longer, it becomes easier to use antenna technology to interact with electromagnetic radiation (although it is possible to make very tiny antenna). The near-infrared can be collected much like visible light, however in the far-infrared and submillimetre range,  telescopes can operate more like a radio telescope. For example, the

text: James Clerk Maxwell Telescope

text: observes from wavelengths from 3 μm (0.003 mm) to 2000 μm (2 mm), but uses a parabolic aluminum antenna. On the other hand, the

text: Spitzer Space Telescope

text: , observing from about 3 μm (0.003 mm) to 180 μm (0.18 mm) uses a mirror (reflecting optics). Also using reflecting optics, the

text: Hubble Space Telescope

text: with

text: Wide Field Camera 3

text: can observe in the frequency range from about 0.2 μm (0.0002 mm) to 1.7 μm (0.0017 mm) (from ultra-violet to infrared light).

text: Optical brightener is used to make paper appear whiter. Optical-brightening agents use fluorescence to absorb invisible radiation from the ultraviolet part of the light spectrum and re-emit the radiation as light in the visible blue range. The optical-brightening agent thus generates blue light that is added to the reflected light. The additional blue light offsets the yellowish tinge that would otherwise exist in the reflected light characteristics. It thus increases the brightness of the material (when the illumination includes ultraviolet radiation).

text: Optical brightener

text: is used to make paper appear whiter. Optical-brightening agents use

text: fluorescence

text: to absorb invisible radiation from the

text: ultraviolet

text: part of the light spectrum and re-emit the radiation as light in the visible blue range. The optical-brightening agent thus generates blue light that is added to the reflected light. The additional blue light offsets the yellowish tinge that would otherwise exist in the reflected light characteristics. It thus increases the brightness of the material (when the illumination includes ultraviolet radiation).

text: The spectral power distribution over the visible spectrum from a source can have varying concentrations of relative SPDs.  The interactions between light and matter affect the absorption and reflectance properties of  materials and subsequently produces a color that varies with source illumination.

text: The spectral power distribution over the

text: visible spectrum

text: from a source can have varying concentrations of relative SPDs.  The interactions between light and matter affect the absorption and reflectance properties of  materials and subsequently produces a color that varies with source illumination.

text: As shown on the series, the streams of matter and antimatter directed into crystallized dilithium are unbalanced: there is usually much more matter in the stream than antimatter. The energy generated in the annihilation reaction heats up the excess deuterium gas, producing a plasma that is used to power the warp drives that allow starships to travel faster than light. In addition, most starships use this plasma as a power source for the ship's systems; in the series Star Trek: Enterprise (2001-2005), this was referred to as an electro-plasma system, (a backronym of the term "EPS", which was used in all other series except the original (1966-1969) series) to refer to a ship's or station's power system. The specific details of this reaction were officially established in the Star Trek: The Next Generation (1987-1994) series and technical manual; in earlier works it is not clearly defined.

text: As shown on the series, the streams of

text: matter

text: and

text: antimatter

text: directed into crystallized dilithium are unbalanced: there is usually much more matter in the stream than antimatter. The energy generated in the annihilation reaction heats up the excess deuterium gas, producing a

text: plasma

text: that is used to power the

text: warp drive

text: s that allow

text: starship

text: s to travel

text: faster than light

text: . In addition, most starships use this plasma as a power source for the ship's systems; in the series

text: Star Trek: Enterprise

text: (2001-2005), this was referred to as an electro-plasma system, (a

text: backronym

text: of the term "EPS", which was used in all other series except

text: the original (1966-1969) series

text: ) to refer to a ship's or station's power system. The specific details of this reaction were officially established in the

text: Star Trek: The Next Generation

text: (1987-1994) series and technical manual; in earlier works it is not clearly defined.

text: In the visible spectrum, black is the absorption of all colors.

text: In the

text: visible spectrum

text: , black is the absorption of all colors.

text: The Mk. II was guided by either the Ferranti Type 86 "Firelight" radar for mobile use, or the larger fixed-emplacement Marconi Type 87 "Scorpion". In addition to its own illumination and tracking antennas, the Scorpion also added one of the receiver antennas out of a missile body on the same frame. This antenna was used to determine what the missile's own receiver was seeing, which was used for jamming detection and assessment. The new radars eliminated problems with ground reflections, allowing the missile to be fired at any visible target, no matter how close to the ground. Combined with the new engines, the Mk. II had an extended altitude performance between 150 ft and 65,000 ft.

text: The Mk. II was guided by either the Ferranti Type 86 "Firelight" radar for mobile use, or the larger fixed-emplacement

text: Marconi

text: Type 87 "Scorpion". In addition to its own illumination and tracking antennas, the Scorpion also added one of the receiver antennas out of a missile body on the same frame. This antenna was used to determine what the missile's own receiver was seeing, which was used for jamming detection and assessment. The new radars eliminated problems with ground reflections, allowing the missile to be fired at any visible target, no matter how close to the ground. Combined with the new engines, the Mk. II had an extended altitude performance between 150 ft and 65,000 ft.

text: Optics is the branch of physics which involves the behavior and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behavior of visible, ultraviolet, and infrared light. Because light is an electromagnetic wave, other forms of electromagnetic radiation such as X-rays, microwaves, and radio waves exhibit similar properties.

text: Optics is the branch of

text: physics

text: which involves the behavior and properties of

text: light

text: , including its interactions with

text: matter

text: and the construction of

text: instruments

text: that use or

text: detect

text: it. Optics usually describes the behavior of

text: visible

text: ultraviolet

text: , and

text: infrared

text: light. Because light is an

text: electromagnetic wave

text: , other forms of

text: electromagnetic radiation

text: such as

text: X-ray

text: s,

text: microwave

text: s, and

text: radio wave

text: s exhibit similar properties.

text: Reflection of light is either specular (mirror-like) or diffuse (retaining the energy, but losing the image) depending on the nature of the interface. In specular reflection the phase of the reflected waves depends on the choice of the origin of coordinates, but the relative phase between s and p (TE and TM) polarizations is fixed by the properties of the media and of the interface between them.

text: Reflection of light is either

text: specular

text: (mirror-like) or

text: diffuse

text: (retaining the

text: energy

text: , but losing the image) depending on the nature of the interface. In specular reflection the

text: phase

text: of the reflected waves depends on the choice of the origin of coordinates, but the relative phase between s and p (TE and TM) polarizations is fixed by the properties of the media and of the interface between them.

text: The most direct observational evidence comes from the Bullet Cluster. In most regions dark and visible matter are found together, due to their gravitational attraction. In the Bullet Cluster however, the two matter types split apart, due to a past collision between two smaller clusters. Electromagnetic interactions between gas particles has caused the gas to slow and concentrate near the point of impact. The galaxies, stars and dark matter continued through with negligible collisions. Lensing observations show two dark matter peaks near the galaxy peaks, as expected in dark matter theory. Since the gas peaks contain more ordinary matter than the stars, modified-gravity theories should show the lensing peaks near the gas peaks, contrary to the observations.

text: The most direct observational evidence comes from the

text: Bullet Cluster

text: . In most regions dark and visible matter are found together, due to their gravitational attraction. In the Bullet Cluster however, the two matter types split apart, due to a past collision between two smaller clusters.

text: Electromagnetic

text: interactions between gas particles has caused the gas to slow and concentrate near the point of impact. The galaxies, stars and dark matter continued through with negligible collisions. Lensing observations show two dark matter peaks near the galaxy peaks, as expected in dark matter theory. Since the gas peaks contain more ordinary matter than the stars, modified-gravity theories should show the lensing peaks near the gas peaks, contrary to the observations.

text: Some radiant barriers are spectrally selective and will preferentially reduce the flow of infra-red radiation in comparison to other wavelengths. For instance low-emissivity (low-e) windows will transmit light and short-wave infra-red energy into a building but reflect back the long-wave infra-red radiation generated by interior furnishings. Similarly, special heat-reflective paints are able to reflect more heat than visible light, or vice versa.

text: Some radiant barriers are spectrally selective and will preferentially reduce the flow of infra-red radiation in comparison to other wavelengths. For instance

text: low-emissivity

text: (low-e) windows will transmit light and short-wave infra-red energy into a building but reflect back the long-wave infra-red radiation generated by interior furnishings. Similarly, special heat-reflective paints are able to reflect more heat than visible light, or vice versa.

text: Photoinhibition occurs in all organisms capable of oxygenic photosynthesis, from vascular plants to cyanobacteria. In both plants and cyanobacteria, blue light causes photoinhibition more efficiently than other wavelengths of visible light, and all wavelengths of ultraviolet light are more efficient than wavelengths of visible light. Photoinhibition is a series of reactions that inhibit different activities of PSII, but there is no consensus on what these steps are. The activity of the oxygen-evolving complex of PSII is often found to be lost before the rest of the reaction centre loses activity. However, inhibition of PSII membranes under anaerobic conditions leads primarily to inhibition of electron transfer on the acceptor side of PSII. Ultraviolet light causes inhibition of the oxygen-evolving complex before the rest of PSII becomes inhibited. Photosystem I (PSI) is less susceptible to light-induced damage than PSII, but slow inhibition of this photosystem has been observed. Photoinhibition of PSI occurs in chilling-sensitive plants and the reaction depends on electron flow from PSII to PSI.

text: Photoinhibition occurs in all organisms capable of oxygenic photosynthesis, from

text: vascular plants

text: to

text: cyanobacteria

text: . In both plants and cyanobacteria, blue light causes photoinhibition more efficiently than other wavelengths of visible light, and all wavelengths of ultraviolet light are more efficient than wavelengths of visible light. Photoinhibition is a series of reactions that inhibit different activities of PSII, but there is no consensus on what these steps are. The activity of the

text: oxygen-evolving complex

text: of PSII is often found to be lost before the rest of the reaction centre loses activity. However, inhibition of PSII membranes under anaerobic conditions leads primarily to inhibition of electron transfer on the acceptor side of PSII. Ultraviolet light causes inhibition of the oxygen-evolving complex before the rest of PSII becomes inhibited.

text: Photosystem I

text: (PSI) is less susceptible to light-induced damage than PSII, but slow inhibition of this photosystem has been observed. Photoinhibition of PSI occurs in chilling-sensitive plants and the reaction depends on electron flow from PSII to PSI.

text: A transmission is a machine in a power transmission system, which provides controlled application of the power. Often the term transmission refers simply to the gearbox that uses gears and gear trains to provide speed and torque conversions from a rotating power source to another device.

text: A transmission is a

text: machine

text: in a power transmission system, which provides controlled application of the power. Often the term transmission refers simply to the gearbox that uses

text: gear

text: s and

text: gear train

text: s to provide

text: speed

text: and

text: torque

text: conversions from a rotating power source to another device.

text: A reflectance type is a set, or type, of reflectances, and a reflectance is a surface's disposition to reflect certain percentages of light specified for each wavelength within the visible spectrum.

text: In terms of number of particles, some estimates imply that nearly all the matter, excluding dark matter, occurs in neutrinos, and that roughly  elementary particles of matter exist in the visible universe, mostly neutrinos. Other estimates imply that roughly  elementary particles exist in the visible universe (not including dark matter), mostly photons, gravitons, and other massless force carriers.

text: In terms of number of particles, some estimates imply that nearly all the matter, excluding

text: dark matter

text: , occurs in neutrinos, and that roughly  elementary particles of matter exist in the visible universe, mostly neutrinos. Other estimates imply that roughly  elementary particles exist in the visible universe (not including

text: dark matter

text: ), mostly photons, gravitons, and other massless force carriers.

text: In reflected UV photography the subject is illuminated directly by UV emitting lamps (radiation sources) or by strong sunlight. A UV transmitting filter is placed on the lens, which allows ultraviolet light to pass and which absorbs or blocks all visible and infrared light. UV filters are made from special colored glass and may be coated or sandwiched with other filter glass to aid in blocking unwanted wavelengths. Examples of UV transmission filters are the Baader-U filter, the Precision-U filter, and the StraightEdgeU ultraviolet bandpass filter, all of which exclude most visible and infrared light. Older filters include the Kodak Wratten 18A, B+W 403, Hoya U-340 and Kenko U-360 most of which need to be used in conjunction with an additional infrared blocking filter. Typically such IR blocking, UV transmissive filters are made from Schott BG-38, BG-39 and BG-40 glass.

text: In reflected UV photography the subject is illuminated directly by UV emitting lamps (radiation sources) or by strong sunlight. A UV transmitting

text: filter

text: is placed on the lens, which allows

text: ultraviolet

text: light to pass and which absorbs or blocks all

text: visible

text: and

text: infrared

text: light. UV filters are made from special colored glass and may be coated or sandwiched with other filter glass to aid in blocking unwanted wavelengths. Examples of UV transmission filters are the Baader-U filter, the Precision-U filter, and the StraightEdgeU ultraviolet bandpass filter, all of which exclude most visible and infrared light. Older filters include the

text: Kodak

text: Wratten 18A, B+W 403, Hoya U-340 and Kenko U-360 most of which need to be used in conjunction with an additional infrared blocking filter. Typically such IR blocking, UV transmissive filters are made from Schott BG-38, BG-39 and BG-40 glass.

text: Pollard's espionage came to light in 1985 when a coworker anonymously reported Pollard's removal of classified material from the NIC. The coworker noted that Pollard did not seem to be taking the material to any known appropriate destination, such as other intelligence agencies in the area. Although Pollard was authorized to transport documents and the coworker said the documents were properly wrapped, it appeared out of place that Pollard would be transporting documents on a Friday afternoon when many workers were focused more on the upcoming weekend rather than on intelligence work. Pollard's direct superior, having to complete extra work at the office on a Saturday, had walked by Pollard's desk and noticed unsecured classified material. Taking the initiative to secure it, the supervisor glanced over it and saw it was unrelated to antiterrorism matters in the Caribbean, which is what the section focused on. Looking at more unrelated documents, the supervisor believed foreign intelligence might be involved, but was unable to determine which nation might be interested.

text: Pollard's espionage came to light in 1985 when a coworker anonymously reported Pollard's removal of classified material from the NIC. The coworker noted that Pollard did not seem to be taking the material to any known appropriate destination, such as other intelligence agencies in the area. Although Pollard was authorized to transport documents and the coworker said the documents were properly wrapped, it appeared out of place that Pollard would be transporting documents on a Friday afternoon when many workers were focused more on the upcoming weekend rather than on intelligence work. Pollard's direct superior, having to complete extra work at the office on a Saturday, had walked by Pollard's desk and noticed unsecured classified material. Taking the initiative to secure it, the supervisor glanced over it and saw it was unrelated to

text: antiterrorism

text: matters in the

text: Caribbean

text: , which is what the section focused on. Looking at more unrelated documents, the supervisor believed foreign intelligence might be involved, but was unable to determine which nation might be interested.

text: Okenone is a carotenoid, a class of pigments ubiquitous across photosynthetic organisms. These conjugated molecules act as accessories in the light harvesting complex. Over 600 carotenoids are known, each with a variety of functional groups that alter their absorption spectrum. Okenone appears to be best adapted to the yellow-green transition (520 nm) of the visible spectrum, capturing light below marine plankton in the ocean. This depth varies based on the community structure of the water column. A survey of microbial blooms found Chromatiaceae anywhere between 1.5m and 24m depth, but more than 75% occurred above 12 meters. Further planktonic sulfur bacteria occupy other niches: green sulfur bacteria, the Chlorobiaceae, that produce the carotenoid chlorobactene were found in greatest abundance above 6m while green sulfur bacteria that produce isorenieratene were predominantly identified above 17m. Finding any of these carotenoids in ancient rocks could constrain the depth of the oxic to anoxic transition as well as confine past ecology. Okenane and chlorobactane discovered in Australian Paleoproterozoic samples allowed conclusions of a temporarily shallow anoxic transition, likely between 12 and 25m.

text: Okenone is a

text: carotenoid

text: , a class of

text: pigments

text: ubiquitous across

text: photosynthetic

text: organisms. These

text: conjugated molecules

text: act as accessories in the

text: light harvesting complex

text: . Over 600 carotenoids are known, each with a variety of

text: functional group

text: s that alter their

text: absorption spectrum

text: . Okenone appears to be best adapted to the yellow-green transition (520 nm) of the

text: visible spectrum

text: , capturing light below

text: marine plankton

text: in the ocean. This depth varies based on the community structure of the water column. A survey of

text: microbial blooms

text: found

text: Chromatiaceae

text: anywhere between 1.5m and 24m depth, but more than 75% occurred above 12 meters. Further planktonic sulfur bacteria occupy other niches:

text: green sulfur bacteria

text: , the

text: Chlorobiaceae

text: , that produce the carotenoid

text: chlorobactene

text: were found in greatest abundance above 6m while green sulfur bacteria that produce

text: isorenieratene

text: were predominantly identified above 17m. Finding any of these carotenoids in ancient rocks could constrain the depth of the

text: oxic to anoxic transition

text: as well as confine past

text: ecology

text: . Okenane and chlorobactane discovered in Australian Paleoproterozoic samples allowed conclusions of a temporarily shallow anoxic transition, likely between 12 and 25m.

text: Georg Wolf (1873–1938) a Berlin manufacturer of rigid endoscopes, established in 1906, produced the Sussmann flexible gastroscope in 1911(Modlin,Farhadi-Journal of Clinical Gastroenterology, 2000).Karl Storz began producing instruments for ENT specialists in 1945. His intention was to develop instruments which would enable the practitioner to look inside the human body. The technology available at the end of the Second World War was still very modest: The area under examination in the interior of the human body was illuminated with miniature electric lamps; alternatively, attempts were made to reflect light from an external source into the body through the endoscopic tube. Karl Storz pursued a plan: he set out to introduce very bright, but cold light into the body cavities through the instrument, thus providing excellent visibility while at the same time allowing objective documentation by means of image transmission.

text: Georg Wolf (1873–1938) a Berlin manufacturer of rigid endoscopes, established in 1906, produced the Sussmann flexible gastroscope in 1911(Modlin,Farhadi-Journal of Clinical Gastroenterology, 2000).Karl Storz began producing instruments for

text: ENT

text: specialists in 1945. His intention was to develop instruments which would enable the practitioner to look inside the human body. The technology available at the end of the Second World War was still very modest: The area under examination in the interior of the human body was illuminated with miniature electric lamps; alternatively, attempts were made to reflect light from an external source into the body through the endoscopic tube. Karl Storz pursued a plan: he set out to introduce very bright, but cold light into the body cavities through the instrument, thus providing excellent visibility while at the same time allowing objective documentation by means of image transmission.

text: When light hits a surface, there are three possible outcomes. Light may be absorbed by the material, light may be transmitted through to the other side, or light may be reflected back. Materials often show some mix of these behaviors, with the proportion of light that goes to each depending on the properties of the material, the wavelength of the light, and the angle of incidence. For most interfaces between materials, the fraction of the light that is reflected increases with increasing angle of incidence

text: When light hits a surface, there are three possible outcomes. Light may be

text: absorbed

text: by the material, light may be

text: transmitted

text: through to the other side, or light may be

text: reflected

text: back. Materials often show some mix of these behaviors, with the proportion of light that goes to each depending on the properties of the material, the wavelength of the light, and the angle of incidence. For most interfaces between materials, the fraction of the light that is reflected increases with increasing angle of incidence

text: Visible light waves from the sun travel in all directions.  When this scattered light meets a horizontal surface, like a road or water, a large portion of the light is reflected with horizontal polarization.  This horizontally-polarized light is seen as white glare, and masks light that is useful to the human eye, reducing visibility.  By using a sheet of vertical polarizing material, the horizontally-polarized component can be significantly attenuated, reducing the overall light level reaching the eye. This improves contrast, and thus perception of the scene.

text: Visible light waves from the sun travel in all directions.  When this scattered light meets a horizontal surface, like a road or water, a large portion of the light is reflected with horizontal polarization.  This horizontally-polarized light is seen as white

text: glare

text: , and masks light that is useful to the

text: human eye

text: , reducing visibility.  By using a sheet of vertical polarizing material, the horizontally-polarized component can be significantly attenuated, reducing the overall light level reaching the eye. This improves contrast, and thus perception of the scene.

text: From dictionary definitions, Frame (2002) insists that "infallibility" is a stronger term than "inerrancy". Inerrant' means there are no errors; 'infallible' means there can be no errors." Yet he agrees that "modern theologians insist on redefining that word also, so that it actually says less than 'inerrancy. Some denominations that teach infallibility hold that the historical or scientific details, which may be irrelevant to matters of faith and Christian practice, may contain errors. This contrasts with the doctrine of Biblical inerrancy, which holds that the scientific, geographic, and historic details of the scriptural texts in their original manuscripts are completely true and without error, though the scientific claims of scripture must be interpreted in the light of the phenomenological nature of the Biblical narratives. For example, Davis suggests "The Bible is inerrant if and only if it makes no false or misleading statements on any topic whatsoever. The Bible is infallible if and only if it makes no false or misleading statements on any matter of faith and practice." In this sense it is seen as distinct from Biblical inerrancy, but always accompanying it. The Chicago Statement on Biblical Inerrancy uses the term in this sense, saying, "Infallibility and inerrancy may be distinguished but not separated."

text: From dictionary definitions, Frame (2002) insists that "infallibility" is a stronger term than "inerrancy". Inerrant' means there are no errors; 'infallible' means there can be no errors." Yet he agrees that "modern theologians insist on redefining that word also, so that it actually says less than 'inerrancy. Some

text: denominations

text: that teach infallibility hold that the historical or scientific details, which may be irrelevant to matters of faith and Christian practice, may contain errors. This contrasts with the doctrine of

text: Biblical inerrancy

text: , which holds that the scientific, geographic, and historic details of the scriptural texts in their original manuscripts are completely true and without error, though the scientific claims of scripture must be interpreted in the light of the

text: phenomenological

text: nature of the Biblical narratives. For example, Davis suggests "The Bible is inerrant if and only if it makes no false or misleading statements on any topic whatsoever. The Bible is infallible if and only if it makes no false or misleading statements on any matter of faith and practice." In this sense it is seen as distinct from

text: Biblical inerrancy

text: , but always accompanying it. The

text: Chicago Statement on Biblical Inerrancy

text: uses the term in this sense, saying, "Infallibility and inerrancy may be distinguished but not separated."

text: Alternatives to optical microscopy which do not use visible light include scanning electron microscopy and transmission electron microscopy.

text: Alternatives to optical microscopy which do not use visible light include

text: scanning electron microscopy

text: and

text: transmission electron microscopy

text: Manual transmissions are the most common type outside North America and Australia. They are cheaper, lighter, usually give better performance, but the newest automatic transmissions, and CVTs give better fuel economy. It is customary for new drivers to learn, and be tested, on a car with a manual gear change. In Malaysia and Denmark all cars used for testing (and because of that, virtually all those used for instruction as well) have a manual transmission. In Japan, the Philippines, Germany, Poland, Italy, Israel, the Netherlands, Belgium, New Zealand, Austria, Bulgaria, the UK, Ireland, Sweden, Norway, Estonia, France, Spain, Switzerland, the Australian states of Victoria, Western Australia and Queensland, Finland, Latvia, Lithuania and the Czech Republic, a test pass using an automatic car does not entitle the driver to use a manual car on the public road; a test with a manual car is required. Manual transmissions are much more common than automatic transmissions in Asia, Africa, South America and Europe.

text: Manual transmissions are the most common type outside

text: North America

text: and

text: Australia

text: . They are cheaper, lighter, usually give better performance, but the newest automatic transmissions, and CVTs give better fuel economy. It is customary for new drivers to learn, and be tested, on a car with a manual gear change. In

text: Malaysia

text: and

text: Denmark

text: all cars used for testing (and because of that, virtually all those used for instruction as well) have a manual transmission. In

text: Japan

text: the Philippines

text: Germany

text: Poland

text: Italy

text: Israel

text: , the

text: Netherlands

text: Belgium

text: New Zealand

text: Austria

text: Bulgaria

text: , the

text: UK

text: , Ireland,

text: Sweden

text: Norway

text: Estonia

text: France

text: Spain

text: Switzerland

text: , the Australian states of

text: Victoria

text: , Western Australia and Queensland,

text: Finland

text: Latvia

text: Lithuania

text: and the

text: Czech Republic

text: , a test pass using an automatic car does not entitle the driver to use a manual car on the public road; a test with a manual car is required. Manual transmissions are much more common than automatic transmissions in

text: Asia

text: Africa

text: South America

text: and

text: Europe

text: Visible light includes radiation with wavelengths between 400 nm and 700 nm, meaning that far infrared photons have less energy than visible light photons.

text: Visible light

text: includes radiation with wavelengths between 400 nm and 700 nm, meaning that far infrared photons have less energy than visible light photons.

text: Unlike in UV/visible spectroscopy, ‘standard’, device independent spectra are not easily attained. Several factors influence and distort the spectra, and corrections are necessary to attain ‘true’, i.e. machine-independent, spectra. The different types of distortions will here be classified as being either instrument- or sample-related. Firstly, the distortion arising from the instrument is discussed. As a start, the light source intensity and wavelength characteristics varies over time during each experiment and between each experiment. Furthermore, no lamp has a constant intensity at all wavelengths. To correct this, a beam splitter can be applied after the excitation monochromator or filter to direct a portion of the light to a reference detector.

text: As with photoacoustic spectroscopy, photothermal spectroscopy is an indirect method for measuring optical absorption, because it is not based on the direct measure of the light which is involved in the absorption. In another sense, however, photothermal (and photoacoustic) methods measure directly the absorption, rather than e.g. calculate it from the transmission, as is the case of more usual (transmission) spectroscopic techniques. And it is this fact that gives the technique its high sensitivity, because in transmission techniques the absorptance is calculated as the difference between total light impinging on the sample and the transmitted (plus reflected, plus scattered) light, with the usual problems of accuracy when one deals with small differences between large numbers, if the absorption is small. In photothermal spectroscopies, instead, the signal is essentially proportional to the absorption, and is zero when there is zero true absorption, even in the presence of reflection or scattering.

text: As with

text: photoacoustic spectroscopy

text: , photothermal spectroscopy is an indirect method for measuring

text: optical absorption

text: , because it is not based on the direct measure of the light which is involved in the absorption. In another sense, however, photothermal (and photoacoustic) methods measure directly the absorption, rather than e.g. calculate it from the transmission, as is the case of more usual (transmission) spectroscopic techniques. And it is this fact that gives the technique its high sensitivity, because in transmission techniques the

text: absorptance

text: is calculated as the difference between total light impinging on the sample and the

text: transmitted

text: (plus

text: reflected

text: , plus

text: scattered

text: ) light, with the usual problems of accuracy when one deals with small differences between large numbers, if the absorption is small. In photothermal spectroscopies, instead, the signal is essentially proportional to the absorption, and is zero when there is zero true absorption, even in the presence of reflection or scattering.

text: The reason for this is that in this definition, electromagnetic radiation (such as light) as well as the energy of electromagnetic fields contributes to the mass of systems, and therefore appears to add matter to them. For example, light radiation (or thermal radiation) trapped inside a box would contribute to the mass of the box, as would any kind of energy inside the box, including the kinetic energy of particles held by the box. Nevertheless, isolated individual particles of light (photons) and the isolated kinetic energy of massive particles, are normally not considered to be matter.

text: The reason for this is that in this definition,

text: electromagnetic radiation

text: (such as light) as well as the energy of

text: electromagnetic field

text: s contributes to the mass of systems, and therefore appears to add matter to them. For example, light radiation (or

text: thermal radiation

text: ) trapped inside a box would contribute to the mass of the box, as would any kind of energy inside the box, including the kinetic energy of particles held by the box. Nevertheless, isolated individual particles of light (

text: photon

text: s) and the isolated kinetic energy of massive particles, are normally not considered to be matter.

text: Other relevant concepts are system, structure, process, type, level, echelon, suprasystem, subsystem, transmissions, and steady state. A system can be conceptual, concrete or abstracted. The structure of a system is the arrangement of the subsystems and their components in three-dimensional space at any point of time. Process, which can be reversible or irreversible, refers to change over time of matter–energy or information in a system. Type defines living systems with similar characteristics. Level is the position in a hierarchy of systems. Many complex living systems, at various levels, are organized into two or more echelons. The suprasystem of any living system is the next higher system in which it is a subsystem or component. The totality of all the structures in a system which carry out a particular process is a subsystem. Transmissions are inputs and outputs in concrete systems. Because living systems are open systems, with continually altering fluxes of matter–energy and information, many of their equilibria are dynamic—situations identified as steady states or flux equilibria.

text: With increasing depth underwater, sunlight is absorbed, and the amount of visible light diminishes. Because absorption is greater for long wavelengths (red end of the visible spectrum) than for short wavelengths (blue end of the visible spectrum), the colour spectrum is rapidly altered with increasing depth. White objects at the surface appear bluish underwater, and red objects appear dark, even black. Although light penetration will be less if water is turbid, in the very clear water of the open ocean less than 25% of the surface light reaches a depth of 10 m (33 feet). At 100 m (330 ft) the light present from the sun is normally about 0.5% of that at the surface.

text: With increasing depth underwater,

text: sunlight

text: is absorbed, and the amount of visible

text: light

text: diminishes. Because absorption is greater for long

text: wavelength

text: s (red end of the

text: visible spectrum

text: ) than for short wavelengths (blue end of the visible spectrum), the

text: colour spectrum

text: is rapidly altered with increasing depth. White objects at the surface appear bluish underwater, and red objects appear dark, even black. Although light penetration will be less if water is

text: turbid

text: , in the very clear water of the open ocean less than 25% of the surface light reaches a depth of 10 m (33 feet). At 100 m (330 ft) the light present from the sun is normally about 0.5% of that at the surface.

text: For nanoparticles, localized surface plasmon oscillations can give rise to the intense colors of suspensions or sols containing the nanoparticles. Nanoparticles or nanowires of noble metals exhibit strong absorption bands in the ultraviolet-visible light regime that are not present in the bulk metal. This extraordinary absorption increase has been exploited to increase light absorption in photovoltaic cells by depositing metal nanoparticles on the cell surface. The energy (color) of this absorption differs when the light is polarized along or perpendicular to the nanowire. Shifts in this resonance due to changes in the local index of refraction upon adsorption to the nanoparticles can also be used to detect biopolymers such as DNA or proteins. Related complementary techniques include plasmon waveguide resonance, QCM, extraordinary optical transmission, and dual polarization interferometry

text: For nanoparticles, localized surface plasmon oscillations can give rise to the intense colors of

text: suspensions

text: or

text: sols

text: containing the

text: nanoparticle

text: s. Nanoparticles or nanowires of noble metals exhibit strong

text: absorption band

text: s in the

text: ultraviolet

text: visible

text: light regime that are not present in the bulk metal. This extraordinary absorption increase has been exploited to increase light absorption in photovoltaic cells by depositing metal nanoparticles on the cell surface. The energy (color) of this absorption differs when the light is polarized along or perpendicular to the nanowire. Shifts in this resonance due to changes in the local index of refraction upon adsorption to the nanoparticles can also be used to detect biopolymers such as DNA or proteins. Related complementary techniques include plasmon waveguide resonance,

text: QCM

text: extraordinary optical transmission

text: , and

text: dual polarization interferometry

text: The existence of exciton states may be inferred from the absorption of light associated with their excitation. Typically, excitons are observed just below the band gap.

text: The existence of exciton states may be inferred from the absorption of light associated with their excitation. Typically, excitons are observed just below the

text: band gap

text: Tyson proceeds to discuss the nature of light as discovered by mankind. Work by Isaac Newton using refraction through prisms demonstrated that light was composed of the visible spectrum, while findings of William Herschel in the 19th century showed that light also consisted of infrared rays. Joseph von Fraunhofer would later come to discover that by magnifying the spectrum of visible light, gaps in the spectrum would be observed. These Fraunhofer lines would later be determined to be caused by the absorption of light by electrons in moving between atomic orbitals when it passed through atoms, with each atom having a characteristic signature due to the quantum nature of these orbitals. This since has led to the core of astronomical spectroscopy, allowing astronomers to make observations about the composition of stars, planets, and other stellar features through the spectral lines, as well as observing the motion and expansion of the universe, and the existence of dark matter.

text: Tyson proceeds to discuss the nature of light as discovered by mankind. Work by

text: Isaac Newton

text: using

text: refraction

text: through

text: prism

text: s demonstrated that light was composed of the

text: visible spectrum

text: , while findings of

text: William Herschel

text: in the 19th century showed that light also consisted of

text: infrared

text: rays.

text: Joseph von Fraunhofer

text: would later come to discover that by magnifying the spectrum of visible light, gaps in the spectrum would be observed. These

text: Fraunhofer lines

text: would later be determined to be caused by the absorption of light by

text: electron

text: s in moving between

text: atomic orbital

text: s when it passed through atoms, with each atom having a characteristic signature due to the

text: quantum nature

text: of these orbitals. This since has led to the core of

text: astronomical spectroscopy

text: , allowing astronomers to make observations about the composition of stars, planets, and other stellar features through the spectral lines, as well as observing the motion and expansion of the universe, and the existence of

text: dark matter

text: Black light paints and inks are commonly used in the production of black light posters. Under daylight, the poster may or may not be vibrant in color, but under black light (with little or no visible light present), the effect produced can be psychedelic. The inks are normally highly sensitive to direct sunlight and other powerful light sources. The fluorescent dyes cause a chemical reaction when exposed to high intensity light sources (HILS) and the visual result is a fading in the colors of the inks. With paper, significant visible change in the color saturation can typically be observed within 45 minutes to one hour of exposure to the HILS. To date, there is no absolute method to prevent this phenomenon, although certain laminations, lacquer coatings and glass or plastic protective sheets can effectively slow the fading characteristics of the dyes.

text: Black light paints and

text: inks

text: are commonly used in the production of

text: black light posters

text: . Under daylight, the poster may or may not be vibrant in color, but under black light (with little or no visible light present), the effect produced can be

text: psychedelic

text: . The inks are normally highly sensitive to direct sunlight and other powerful light sources. The fluorescent dyes cause a chemical reaction when exposed to high intensity light sources (HILS) and the visual result is a fading in the colors of the inks. With paper, significant visible change in the color saturation can typically be observed within 45 minutes to one hour of exposure to the HILS. To date, there is no absolute method to prevent this phenomenon, although certain laminations, lacquer coatings and glass or plastic protective sheets can effectively slow the fading characteristics of the dyes.

text: Reflectivity is light reflected from a source to a surface and  returned to its original source.  For traffic signs and vehicle operators, the light source is a vehicle’s headlights, where the light is sent to the traffic sign face and then returned to the vehicle operator. Traffic signs are manufactured with retroreflective sheeting so that the traffic sign is visible at night. Reflective sign faces are manufactured with glass beads or prismatic reflectors imbedded in the sheeting so that the face reflects light, therefore making the sign appear more bright and visible to the vehicle operator. According to the National Highway Traffic Safety Administration (NHTSA), the Traffic Safety Facts 2000 publication states the fatal crash rate is 3-4 times more likely during nighttime crashes than daytime incidents.

text: Reflectivity is light reflected from a source to a surface and  returned to its original source.  For traffic signs and vehicle operators, the light source is a vehicle’s headlights, where the light is sent to the traffic sign face and then returned to the vehicle operator. Traffic signs are manufactured with retroreflective sheeting so that the traffic sign is visible at night. Reflective sign faces are manufactured with glass beads or prismatic reflectors imbedded in the sheeting so that the face reflects light, therefore making the sign appear more bright and visible to the vehicle operator. According to the

entity_name: National Highway Traffic Safety Administration

text: National Highway Traffic Safety Administration

text: (NHTSA), the Traffic Safety Facts 2000 publication states the fatal crash rate is 3-4 times more likely during nighttime crashes than daytime incidents.

text: Iota Librae is a complex multiple star, 377 light-years from Earth, with both optical and true binary components. The primary appears as a blue-white star of magnitude 4.5; it is a binary star indivisible in even the largest amateur instruments with a period of 23 years. The secondary, visible in small telescopes as a star of magnitude 9.4, is a binary with two components, magnitudes 10 and 11. There is an optical companion to Iota Librae; 25 Librae is a star of magnitude 6.1, 219 light-years from Earth and visible in binoculars. Mu Librae is a binary star divisible in medium-aperture amateur telescopes, 235 light-years from Earth. The primary is of magnitude 5.7 and the secondary is of magnitude 6.8.

text: Iota Librae

text: is a complex multiple star, 377 light-years from Earth, with both optical and true binary components. The primary appears as a blue-white star of magnitude 4.5; it is a binary star indivisible in even the largest amateur instruments with a period of 23 years. The secondary, visible in small telescopes as a star of magnitude 9.4, is a binary with two components, magnitudes 10 and 11. There is an optical companion to Iota Librae;

text: 25 Librae

text: is a star of magnitude 6.1, 219 light-years from Earth and visible in binoculars.

text: Mu Librae

text: is a binary star divisible in medium-aperture amateur telescopes, 235 light-years from Earth. The primary is of magnitude 5.7 and the secondary is of magnitude 6.8.

text: This dark matter model is also known as BEC dark matter or wave dark matter.  Fuzzy dark matter and ultra-light axion are  examples of scalar field dark matter.

text: This dark matter model is also known as BEC dark matter or wave dark matter.

text: Fuzzy dark matter

text: and ultra-light axion are  examples of scalar field dark matter.

text: Light transmission efficiency is greatest if the tube is short and straight. In longer, angled, or flexible tubes, part of the light intensity is lost. To minimize losses, a high reflectivity of the tube lining is crucial; manufacturers claim reflectivities of their materials, in the visible range, of up to almost 99.5 percent.

text: Konstal 102N was directly descended from the older 13N produded by Konstal between 1959 and 1969, but, unlike 13N, it was an articulated tram - basically two 13N cars connected by a pivot. Most of the electrical equipment remained unchanged; the body of the tram is where the most dramatic changes were visible. The streamlined design of 13N was replaced by a more boxy shape which made for excellent visibility - unfortunately in daytime only. The large windscreen was tilted is such a way that at night-time it reflected light directly into the driver's eyes making the 102N difficult to drive after dark. This issue was ultimately to prove the downfall of the 102N, as after producing just 42 units the company decided to abandon the 102N project, and in 1970 reverted to the 13N look for the newer 102Na model.

text: Konstal 102N was directly descended from the older

text: produded by Konstal between 1959 and 1969, but, unlike 13N, it was an articulated tram - basically two 13N cars connected by a pivot. Most of the electrical equipment remained unchanged; the body of the tram is where the most dramatic changes were visible. The streamlined design of 13N was replaced by a more boxy shape which made for excellent visibility - unfortunately in daytime only. The large windscreen was tilted is such a way that at night-time it reflected light directly into the driver's eyes making the 102N difficult to drive after dark. This issue was ultimately to prove the downfall of the 102N, as after producing just 42 units the company decided to abandon the 102N project, and in 1970 reverted to the 13N look for the newer

text: model.

text: Traffic risks to the cyclist are similar to those faced by motorcyclists (see SMIDSY), with the main differences being that bicycling speeds are typically lower, and the bicyclist wears less protective gear. In a 2009 study, Most UK cyclists and almost all motorists believed that high-visibility clothing would increase cyclists' visibility. Almost all drivers agreed that cyclists need to wear reflective clothing in low lighting environments, whereas less than three-quarters of cyclists (72%) agreed, and less than half claimed that they always did so.

text: Fluorescent lamps consist of a glass tube that contains mercury vapour or argon under low pressure. Electricity flowing through the tube causes the gases to give off ultraviolet energy. The inside of the tubes are coated with phosphors that give off visible light when struck by ultraviolet energy.They have much higher efficiency than incandescent lamps. For the same amount of light generated, they typically use around one-quarter to one-third the power of an incandescent. The typical luminous efficacy of fluorescent lighting systems is 50–100 lumens per watt, several times the efficacy of incandescent bulbs with comparable light output. Fluorescent lamp fixtures are more costly than incandescent lamps because they require a ballast to regulate the current through the lamp, but the lower energy cost typically offsets the higher initial cost. Compact fluorescent lamps are now available in the same popular sizes as incandescents and are used as an energy-saving alternative in homes. Because they contain mercury, many fluorescent lamps are classified as hazardous waste. The United States Environmental Protection Agency recommends that fluorescent lamps be segregated from general waste for recycling or safe disposal, and some jurisdictions require recycling of them.

text: Fluorescent

text: lamps consist of a glass tube that contains mercury vapour or argon under low pressure. Electricity flowing through the tube causes the gases to give off ultraviolet energy. The inside of the tubes are coated with

text: phosphor

text: s that give off visible light when struck by ultraviolet energy.They have much higher efficiency than incandescent lamps. For the same amount of light generated, they typically use around one-quarter to one-third the power of an incandescent. The typical

text: luminous efficacy

text: of fluorescent lighting systems is 50–100 lumens per watt, several times the efficacy of incandescent bulbs with comparable light output. Fluorescent lamp fixtures are more costly than incandescent lamps because they require a

text: ballast

text: to regulate the

text: current

text: through the lamp, but the lower energy cost typically offsets the higher initial cost.

text: Compact fluorescent lamp

text: s are now available in the same popular sizes as incandescents and are used as an

text: energy-saving

text: alternative in homes. Because they contain mercury, many fluorescent lamps are classified as

text: hazardous waste

text: . The

entity_name: United States Environmental Protection Agency

text: United States Environmental Protection Agency

text: recommends that fluorescent lamps be segregated from general waste for

text: recycling

text: or safe disposal, and some jurisdictions require recycling of them.

text: The visibility of objects, excluding light-emitting ones, is primarily caused by diffuse reflection of light: it is diffusely-scattered light that forms the image of the object in the observer's eye.

text: Because elements only use power in order to switch between on and off states (no power is needed to reflect or absorb light hitting the display once the element is either reflecting or absorbing), IMOD-based displays potentially use much less power than displays that generate light and/or need constant power to keep pixels in a particular state. Being a reflective display, they require an external light source (such as daylight or a lamp) to be readable, just like paper or other electronic paper technologies.

text: Because elements only use power in order to switch between on and off states (no power is needed to reflect or absorb light hitting the display once the element is either reflecting or absorbing), IMOD-based displays potentially use much less power than displays that generate light and/or need constant power to keep pixels in a particular state. Being a reflective display, they require an external light source (such as daylight or a lamp) to be readable, just like

text: paper

text: or other

text: electronic paper

text: technologies.

text: Chemical absorption or reactive absorption is a chemical reaction between the absorbed and the absorbing substances. Sometimes it combines with physical absorption. This type of absorption depends upon the stoichiometry of the reaction and the concentration of its reactants.

text: Chemical absorption or reactive absorption is a chemical reaction between the absorbed and the absorbing substances. Sometimes it combines with physical absorption. This type of absorption depends upon the

text: stoichiometry

text: of the reaction and the concentration of its reactants.

text: Cygnus A is the first radio galaxy discovered; at a distance of 730 million light-years from Earth, it is the closest powerful radio galaxy. In the visible spectrum, it appears as an elliptical galaxy in a small cluster. It is classified as an active galaxy because the supermassive black hole at its nucleus is accreting matter, which produces two jets of matter from the poles. The jets' interaction with the interstellar medium creates radio lobes, one source of radio emissions.

text: Cygnus A

text: is the first

text: radio galaxy

text: discovered; at a distance of 730 million light-years from Earth, it is the closest powerful radio galaxy. In the

text: visible spectrum

text: , it appears as an

text: elliptical galaxy

text: in a small

text: cluster

text: . It is classified as an

text: active galaxy

text: because the

text: supermassive black hole

text: at its

text: nucleus

text: is accreting matter, which produces two

text: jets

text: of matter from the poles. The jets' interaction with the

text: interstellar medium

text: creates radio lobes, one source of radio emissions.

text: Sickert often professed his distaste for what he termed the "beastly" character of thickly textured paint. In an article he wrote for The Fortnightly Review in 1911, he described his reaction to the paintings of Van Gogh: "I execrate his treatment of the instrument I love, these strips of metallic paint that catch the light like so many dyed straws ... my teeth are set on edge". In response to Alfred Wolmark's work he declared that "thick oil-paint is the most undecorative matter in the world".

text: Sickert often professed his distaste for what he termed the "beastly" character of thickly textured paint. In an article he wrote for

text: The Fortnightly Review

text: in 1911, he described his reaction to the paintings of

text: Van Gogh

text: : "I execrate his treatment of the instrument I love, these strips of metallic paint that catch the light like so many dyed straws ... my teeth are set on edge". In response to

text: Alfred Wolmark

text: 's work he declared that "thick oil-paint is the most undecorative matter in the world".

text: Light, or visible light, is a very narrow range of electromagnetic radiation of a wavelength that is visible to the human eye, or 380–750 nm which equates to a frequency range of 790 to 400 THz respectively. More broadly, physicists use the term "light" to mean electromagnetic radiation of all wavelengths, whether visible or not.

text: Umbelliferone absorbs strongly at 300, 305 and 325 nm, with log ε values of 3.9, 3.95 and 4.15 respectively, and it fluoresces blue in both ultraviolet and visible light. The powerful absorption at three different wavelengths, coupled with the fact that the energy is dissipated safely as visible light, make umbelliferone a useful sunscreen agent. The absorption changes in alkaline solution, since the phenolic hydroxyl group is deprotonated (pK = 7.7).

text: Umbelliferone absorbs strongly at 300, 305 and 325

text: nm

text: , with log

text: ε

text: values of 3.9, 3.95 and 4.15 respectively, and it fluoresces blue in both ultraviolet and visible light. The powerful absorption at three different wavelengths, coupled with the fact that the energy is dissipated safely as visible light, make umbelliferone a useful sunscreen agent. The absorption changes in

text: alkali

text: ne solution, since the phenolic

text: hydroxyl

text: group is

text: deprotonated

text: pK

text: = 7.7).

text: The remaining 4.9% of the mass–energy of the Universe is ordinary matter, that is, atoms, ions, electrons and the objects they form. This matter includes stars, which produce nearly all of the light we see from galaxies, as well as interstellar gas in the interstellar and intergalactic media, planets, and all the objects from everyday life that we can bump into, touch or squeeze. As a matter of fact, the great majority of ordinary matter in the universe is unseen, since visible stars and gas inside galaxies and clusters account for less than 10 per cent of the ordinary matter contribution to the mass-energy density of the universe.

text: The remaining 4.9% of the mass–energy of the Universe is ordinary matter, that is,

text: atom

text: s,

text: ion

text: s,

text: electron

text: s and the objects they form. This matter includes

text: star

text: s, which produce nearly all of the light we see from galaxies, as well as interstellar gas in the

text: interstellar

text: and

text: intergalactic

text: media,

text: planet

text: s, and all the objects from everyday life that we can bump into, touch or squeeze. As a matter of fact, the great majority of ordinary matter in the universe is unseen, since visible stars and gas inside galaxies and clusters account for less than 10 per cent of the ordinary matter contribution to the mass-energy density of the universe.

text: In the EUV portion of the spectrum (wavelengths shorter than about 30 nm) nearly all materials absorb strongly, making it difficult to focus or otherwise manipulate light in this wavelength range.  Telescopes such as TRACE or EIT that form images with EUV light use multilayer mirrors that are constructed of hundreds of alternating layers of a high-mass metal such as molybdenum or tungsten, and a low-mass spacer such as silicon, vacuum deposited onto a substrate such as glass.  Each layer pair is designed to have a thickness equal to half the wavelength of light to be reflected.  Constructive interference between scattered light from each layer causes the mirror to reflect EUV light of the desired wavelength as would a normal metal mirror in visible light.  Using multilayer optics it is possible to reflect up to 70% of incident EUV light (at a particular wavelength chosen when the mirror is constructed).

text: In the

text: EUV

text: portion of the spectrum (wavelengths shorter than about 30 nm) nearly all materials absorb strongly, making it difficult to focus or otherwise manipulate light in this wavelength range.  Telescopes such as

text: TRACE

text: or

text: EIT

text: that form images with EUV light use multilayer mirrors that are constructed of hundreds of alternating layers of a high-mass metal such as

text: molybdenum

text: or

text: tungsten

text: , and a low-mass spacer such as

text: silicon

text: vacuum deposited

text: onto a substrate such as

text: glass

text: .  Each layer pair is designed to have a thickness equal to half the wavelength of light to be reflected.

text: Constructive interference

text: between scattered light from each layer causes the mirror to reflect EUV light of the desired wavelength as would a normal metal mirror in visible light.  Using multilayer optics it is possible to reflect up to 70% of incident EUV light (at a particular wavelength chosen when the mirror is constructed).

text: The different chlorophyll and non-chlorophyll pigments associated with the photosystems all have different absorption spectra, either because the spectra of the different chlorophyll pigments are modified by their local protein environment or because the accessory pigments have intrinsic structural differences. The result is that, in vivo, a composite absorption spectrum of all these pigments is broadened and flattened such that a wider range of visible and infrared radiation is absorbed by plants and algae. Most photosynthetic organisms do not absorb green light well, thus most remaining light under leaf canopies in forests or under water with abundant plankton is green, a spectral effect called the "green window". Organisms such as some cyanobacteria and red algae contain accessory phycobiliproteins that absorb green light reaching these habitats.

text: The different chlorophyll and non-chlorophyll pigments associated with the photosystems all have different

text: absorption spectra

text: , either because the spectra of the different chlorophyll pigments are modified by their local protein environment or because the accessory pigments have intrinsic structural differences. The result is that,

text: in vivo

text: , a composite absorption spectrum of all these pigments is broadened and flattened such that a wider range of

text: visible

text: and

text: infrared

text: radiation is absorbed by plants and algae. Most photosynthetic organisms do not absorb green light well, thus most remaining light under leaf canopies in forests or under water with abundant plankton is green, a spectral effect called the "green window". Organisms such as some

text: cyanobacteria

text: and

text: red algae

text: contain accessory

text: phycobiliprotein

text: s that absorb green light reaching these habitats.

text: As the situation is modeled in finer detail, using the general principle of relativity, the concept of a frame-dependent gravitational field becomes less realistic. In these Machian models, the accelerated body can agree that the apparent gravitational field is associated with the motion of the background matter, but can also claim that the motion of the material as if there is a gravitational field, causes the gravitational field - the accelerating background matter "drags light". Similarly, a background observer can argue that the forced acceleration of the mass causes an apparent gravitational field in the region between it and the environmental material (the accelerated mass also "drags light").This "mutual" effect, and the ability of an accelerated mass to warp lightbeam geometry and lightbeam-based coordinate systems, is referred to as frame-dragging.

text: As the situation is modeled in finer detail, using the

text: general principle of relativity

text: , the concept of a frame-dependent gravitational field becomes less realistic. In these

text: Machian

text: models, the accelerated body can agree that the apparent gravitational field is associated with the motion of the background matter, but can also claim that the motion of the material as if there is a gravitational field, causes the gravitational field - the accelerating background matter "

text: drags light

text: ". Similarly, a background observer can argue that the forced acceleration of the mass causes an apparent gravitational field in the region between it and the environmental material (the accelerated mass also "drags light").This "mutual" effect, and the ability of an accelerated mass to warp lightbeam geometry and lightbeam-based coordinate systems, is referred to as

text: frame-dragging

text: The predominant form of automatic transmission is hydraulically operated; using a fluid coupling or torque converter, and a set of planetary gearsets to provide a range of gear ratios.

text: The predominant form of automatic transmission is

text: hydraulically

text: operated; using a

text: fluid coupling

text: or torque converter, and a set of

text: planetary gearsets

text: to provide a range of gear ratios.

text: Dunn often speaks out on and in support of queer visibility and queer youth online. In one of her YouTube videos, "#WHYiVLOG? Bisexual Visibility Matters!", she discusses bisexual visibility online and why this empowers her to keep creating content. She states in response to why she creates videos that it's important to her, "...to show queer youth and queer teens that you can grow up and be successful and be happy and not just the character that i am on JBU which is essentially me. But me in real life, to be an example of somebody who is out, who is happy, who had friends, and relationships, and careers. It was really important for me for kids to go online and see that." She continues to create content on JBU and her personal Youtube channel that openly talks about her sexuality and queer visibility.

text: In physics, absorption of electromagnetic radiation is the way in which the energy of a photon is taken up by matter, typically the electrons of an atom. Thus, the electromagnetic energy is transformed into internal energy of the absorber, for example thermal energy.  The reduction in intensity of a light wave propagating through a medium by absorption of a part of its photons is often called attenuation. Usually, the absorption of waves does not depend on their intensity (linear absorption), although in certain conditions (usually, in optics), the medium changes its transparency dependently on the intensity of waves going through, and saturable absorption (or nonlinear absorption) occurs.

text: In

text: physics

text: , absorption of

text: electromagnetic radiation

text: is the way in which the

text: energy

text: of a

text: photon

text: is taken up by matter, typically the

text: electrons

text: of an

text: atom

text: . Thus, the

text: electromagnetic energy

text: is transformed into

text: internal energy

text: of the absorber, for example

text: thermal energy

text: .  The reduction in intensity of a light wave

text: propagating

text: through a medium by absorption of a part of its photons is often called

text: attenuation

text: optics

text: ), the medium changes its transparency dependently on the intensity of waves going through, and

text: saturable absorption

text: (or nonlinear absorption) occurs.

text: It is still unclear as to why this object is emitting the Lyman-alpha emission radiation. It is thought that the light is coming from galaxies within the central region of the blob. Light of such intensities could be from active galaxies or supermassive black holes actively absorbing matter. An alternate theory is that the light is from cooling gas falling into early galaxies, which has possibly come from cosmic filaments (as galaxies are thought to form at the intersections of these filaments), however the pattern of polarisation found argues against this.

text: It is still unclear as to why this object is emitting the Lyman-alpha emission radiation. It is thought that the light is coming from galaxies within the central region of the blob. Light of such intensities could be from active galaxies or supermassive black holes actively absorbing matter. An alternate theory is that the light is from cooling gas falling into early galaxies, which has possibly come from cosmic

text: filaments

text: (as galaxies are thought to form at the intersections of these filaments), however the pattern of polarisation found argues against this.

text: The version of Nathaniel Adam/Monarch depicted in the Countdown series was one of the most powerful beings in the DC Universe and was capable of engaging and defeating even vastly powerful foes, such as the Universal Monitors. Monarch's powers stem from his ability to manipulate the quantum field, and he has demonstrated the powers of flight, teleportation (even between different realities), vastly powerful energy projection, manipulation and absorption abilities, vast superhuman strength and invulnerability (Superman's punches didn't even phase him), matter absorption and manipulation abilities and vast though vaguely defined awareness.

text: The 1967 models got some styling tweaks that resulted in a longer, more straightforward appearance. Large wraparound taillamps went into a new rear end with standard backup lights. Otherwise, visible change was modest. "What you'll see inside," claimed the sales brochure for the 1967 Chevelle, "will probably bring on a severe compulsion to go driving." Front disc brakes were available on all models, and a new dual master cylinder brake system incorporated a warning light.  Chevrolet also added 14" wheels and a three speed automatic transmission to their line of transmissions. An entire host of new safety equipment became standard, including a collapsible steering column making the 1967 models safer cars.  The SS396 continued as its own series with both sport coupe and convertible body styles. The 375-horsepower 396-cubic-inch V8 was dropped from the options list until late in the model year and returned with little fanfare resulting in only 612 being sold. Buyers selected from no less than seven transmissions: two manual three-speeds, two manual four-speeds, an overdrive three-speed, and two automatics. The manual-shift feature of the Turbo Hydra-Matic transmission was touted in advertising. Options included Superlift air shock absorbers, Strato-ease headrests, and special instrumentation. Although Chevy's big news for 1967 was the introduction of the Camaro, Chevelle offered a more traditional sort of sportiness.

text: For the deluded, matter seems to appear. This is due to non-recognition of the five lights. Matter includes the mahābhūta or classical elements, namely: space, air, water, fire, earth. The illusion of matter includes even the formless realms and the minds of sentient beings. For example, the beings of the formless realms are made of subtle matter.  And the mind of a human is merely matter, specifically vayu (wind, air).

text: For the deluded, matter seems to appear. This is due to non-recognition of the five lights. Matter includes the

text: mahābhūta

text: or classical elements, namely: space, air, water, fire, earth. The illusion of matter includes even the

text: formless realms

text: and the minds of sentient beings. For example, the beings of the formless realms are made of subtle matter.  And the mind of a human is merely matter, specifically

text: vayu

text: (wind, air).

text: This method uses a similar principle to how a prism works to separate white light into its component colors. A gemological spectroscope is employed to analyze the selective absorption of light in the gem material. Essentially, when light passes from one medium to another, it bends. Blue light bends more than red light. How much the light bends will vary depending on the gem material. Coloring agents or chromophores show bands in the spectroscope and indicate which element is responsible for the gem's color.

text: This method uses a similar principle to how a

text: prism

text: works to separate white light into its component colors. A gemological

text: spectroscope

text: is employed to analyze the selective absorption of light in the gem material. Essentially, when light passes from one medium to another, it bends. Blue light bends more than red light. How much the light bends will vary depending on the gem material. Coloring agents or chromophores show bands in the spectroscope and indicate which element is responsible for the gem's color.

text: Reflection is accomplished in a ray trace renderer by following a ray from the eye to the mirror and then calculating where it bounces from, and continuing the process until no surface is found, or a non-reflective surface is found. Reflection on a shiny surface like wood or tile can add to the photorealistic effects of a 3D rendering.

text: The term venous translucence (or translumination) has been used in phlebology since 1996 by surgeon Pedro Fernandes Neto during ambulatory clinical exams in Brazil. His results were published in the annals of the national and international congresses of angiology. Venous translucence is the process of reflective image visualization of veins by light, which reaches up to the superficial venous system. It is a non-invasive method. Since it is a simple, low-cost technique it can be repeated as needed, which is useful in disease-process monitoring. It is a new diagnostic procedure, still undergoing investigation; more analysis is necessary to hone its technical aspects. Venous translucence is based on optical physics. It is caused by the refraction, absorption and reflection of light (whose principle is the dispersion and absorption of light). The color which is not absorbed is reflected, and is the one that is seen. Therefore, venous translumination is based on the incidence of luminousity on the vein, where part of the light is absorbed and another reflected (supplying a silhouette of the vein in question).

text: The term venous

text: translucence

text: (or translumination) has been used in

text: phlebology

text: since 1996 by surgeon Pedro Fernandes Neto during ambulatory clinical exams in

text: Brazil

text: . His results were published in the annals of the national and international congresses of

text: angiology

text: . Venous translucence is the process of reflective

text: image

text: visualization of veins by

text: light

text: , which reaches up to the superficial venous system. It is a non-invasive method. Since it is a simple, low-cost technique it can be repeated as needed, which is useful in disease-process monitoring. It is a new diagnostic procedure, still undergoing investigation; more analysis is necessary to hone its technical aspects. Venous translucence is based on optical physics. It is caused by the refraction,

text: absorption

text: and

text: reflection

text: of light (whose principle is the

text: dispersion

text: and absorption of

text: light

text: ). The color which is not absorbed is reflected, and is the one that is seen. Therefore, venous translumination is based on the incidence of luminousity on the vein, where part of the light is absorbed and another

text: reflected

text: (supplying a

text: silhouette

text: of the vein in question).

text: During the past century, astronomy has been revolutionized by the use of new methods for observing the universe. Astronomical observations were originally made using visible light. Galileo Galilei pioneered the use of telescopes to enhance these observations. However, visible light is only a small portion of the electromagnetic spectrum, and not all objects in the distant universe shine strongly in this particular band. More useful information may be found, for example, in radio wavelengths. Using radio telescopes, astronomers have found pulsars, quasars, and other extreme objects that push the limits of our understanding of physics. Observations in the microwave band have opened our eyes to the faint imprints of the Big Bang, a discovery Stephen Hawking called the "greatest discovery of the century, if not all time". Similar advances in observations using gamma rays, x-rays, ultraviolet light, and infrared light have also brought new insights to astronomy. As each of these regions of the spectrum has opened, new discoveries have been made that could not have been made otherwise. Astronomers hope that the same holds true of gravitational waves.

text: During the past century,

text: astronomy

text: has been revolutionized by the use of new methods for observing the universe. Astronomical observations were originally made using

text: visible light

text: Galileo Galilei

text: pioneered the use of telescopes to enhance these observations. However, visible light is only a small portion of the

text: electromagnetic spectrum

text: , and not all objects in the distant universe shine strongly in this particular band. More useful information may be found, for example, in radio wavelengths. Using

text: radio telescopes

text: , astronomers have found

text: pulsars

text: quasars

text: , and other extreme objects that push the limits of our understanding of physics. Observations in the

text: microwave

text: band have opened our eyes to the

text: faint imprints

text: of the

text: Big Bang

text: , a discovery

text: Stephen Hawking

text: called the "greatest discovery of the century, if not all time". Similar advances in observations using

text: gamma ray

text: s,

text: x-ray

text: s,

text: ultraviolet light

text: , and

text: infrared light

text: have also brought new insights to astronomy. As each of these regions of the spectrum has opened, new discoveries have been made that could not have been made otherwise. Astronomers hope that the same holds true of gravitational waves.

text: More generally, transmission of unguided optical signals is known as optical wireless communications (OWC). Examples include medium-range visible light communication and short-distance IrDA, using infrared LEDs.

text: More generally, transmission of unguided optical signals is known as

text: optical wireless communications

text: (OWC). Examples include medium-range

text: visible light communication

text: and short-distance

text: IrDA

text: , using infrared LEDs.

text: Plasmas are by far the most common phase of ordinary matter in the universe, both by mass and by volume. Essentially, all of the visible light from space comes from stars, which are plasmas with a temperature such that they radiate strongly at visible wavelengths. Most of the ordinary (or baryonic) matter in the universe, however, is found in the intergalactic medium, which is also a plasma, but much hotter, so that it radiates primarily as X-rays.

text: Plasmas are by far the most common

text: phase of ordinary matter

text: in the universe, both by mass and by volume. Essentially, all of the visible light from space comes from stars, which are plasmas with a temperature such that they radiate strongly at visible wavelengths. Most of the ordinary (or

text: baryon

text: ic) matter in the universe, however, is found in the

text: intergalactic medium

text: , which is also a plasma, but much hotter, so that it radiates primarily as X-rays.

text: The transmission is monitored and regulated by Audi's "Dynamic Regulating Programme" (DRP), which tracks the driver's inputs (from how the driver applies the throttle pedal), driving conditions, and engine load - to compute the optimal gear ratio for fuel efficiency or maximum performance, as mandated by the user.  The transmission can select pre-programmed underdrive to increase performance, or overdrive to improve economy.  From 2004, Multitronic transmissions offered manual selection of a 'sport mode' to pre-select the performance mapping.  The electronic system also includes sensors to detect whether the vehicle is traveling downhill, and provides additional engine braking in such circumstances.  Multitronic also offers a number of driver-selectable fixed ratios, selectable from either the gear-lever in a sequential style, or via (optional) steering wheel-mounted fingertip paddle-shift controls.

text: The transmission is monitored and regulated by

text: Audi

text: 's "Dynamic Regulating Programme" (DRP), which tracks the driver's inputs (from how the driver applies the throttle pedal), driving conditions, and engine load - to compute the optimal

text: gear ratio

text: for fuel efficiency or maximum performance, as mandated by the user.  The transmission can select pre-programmed underdrive to increase performance, or overdrive to improve economy.  From 2004, Multitronic transmissions offered manual selection of a 'sport mode' to pre-select the performance mapping.  The electronic system also includes sensors to detect whether the vehicle is traveling downhill, and provides additional

text: engine braking

text: in such circumstances.  Multitronic also offers a number of driver-selectable fixed ratios, selectable from either the gear-lever in a sequential style, or via (optional) steering wheel-mounted fingertip paddle-shift controls.

text: The light-coloured area of blown lunar surface dust created by the lunar module engine blast at the Apollo 15 landing site was photographed and confirmed by comparative analysis of photographs in May 2008. They correspond well to photographs taken from the Apollo 15 Command/Service Module showing a change in surface reflectivity due to the plume. This was the first visible trace of manned landings on the Moon seen from space since the close of the Apollo program.

text: The light-coloured area of blown lunar surface dust created by the lunar module engine blast at the Apollo 15 landing site was photographed and confirmed by comparative analysis of photographs in May 2008. They correspond well to photographs taken from the Apollo 15

text: Command/Service Module

text: showing a change in surface reflectivity due to the plume. This was the first visible trace of manned landings on the

text: Moon

text: seen from space since the close of the

text: Apollo program

text: We hear no more about most of these planets, though in the short story "The Matter of Seggri", it is mentioned that 4-Taurus is also known as Iao.  Argaven XVII visits Ollul in the short story "Winter's King", a trip of 24 light-years each way; this contradicts the stated fact in The Left Hand of Darkness that Ollul is 17 light-years away from Gethen.  As for S, it is possible that S is another name for Athshe.

text: We hear no more about most of these planets, though in the short story "

text: The Matter of Seggri

text: ", it is mentioned that 4-Taurus is also known as Iao.  Argaven XVII visits Ollul in the short story "

text: Winter's King

text: ", a trip of 24 light-years each way; this contradicts the stated fact in The Left Hand of Darkness that Ollul is 17 light-years away from Gethen.  As for S, it is possible that S is another name for Athshe.

text: PMMA transmits up to 92% of visible light (3 mm thickness), and gives a reflection of about 4% from each of its surfaces due to its refractive index (1.4905 at 589.3 nm). It filters ultraviolet (UV) light at wavelengths below about 300 nm (similar to ordinary window glass). Some manufacturers add coatings or additives to PMMA to improve absorption in the 300–400 nm range. PMMA passes infrared light of up to 2,800 nm and blocks IR of longer wavelengths up to 25,000 nm. Colored PMMA varieties allow specific IR wavelengths to pass while blocking visible light (for remote control or heat sensor applications, for example).

text: PMMA

text: transmits

text: up to 92% of

text: visible light

text: (3 mm thickness), and gives a reflection of about 4% from each of its surfaces due to its

text: refractive index

text: (1.4905 at 589.3 nm). It filters

text: ultraviolet

text: (UV) light at wavelengths below about 300

text: nm

text: (similar to ordinary window glass). Some manufacturers add coatings or additives to PMMA to improve absorption in the 300–400 nm range. PMMA passes

text: infrared

text: light of up to 2,800 nm and blocks IR of longer

text: wavelength

text: s up to 25,000 nm. Colored PMMA varieties allow specific IR wavelengths to pass while blocking

text: visible light

text: (for

text: remote control

text: or heat sensor applications, for example).

text: The term 'whispering gallery' has been borrowed in the physical sciences to describe other forms of whispering-gallery waves such as light or matter waves.

text: The term 'whispering gallery' has been borrowed in the physical sciences to describe other forms of

text: whispering-gallery wave

text: s such as

text: light

text: or

text: matter wave

text: s.

text: As in benzene, in substances such as beta carotene, chlorophyll, or heme, some electrons in the π orbitals are spread out in molecular orbitals over long distances in a molecule, resulting in light absorption in lower energies (the visible spectrum), which accounts for the characteristic colours of these substances. This and other spectroscopic data for molecules are well explained in MO theory, with an emphasis on electronic states associated with multicenter orbitals, including mixing of orbitals premised on principles of orbital symmetry matching. The same MO principles also naturally explain some electrical phenomena, such as high electrical conductivity in the planar direction of the hexagonal atomic sheets that exist in graphite. This results from continuous band overlap of half-filled p orbitals and explains electrical conduction. MO theory recognizes that some electrons in the graphite atomic sheets are completely delocalized over arbitrary distances, and reside in very large molecular orbitals that cover an entire graphite sheet, and some electrons are thus as free to move and therefore conduct electricity in the sheet plane, as if they resided in a metal.

text: As in benzene, in substances such as

text: beta carotene

text: chlorophyll

text: , or

text: heme

text: , some electrons in the π orbitals are spread out in molecular orbitals over long distances in a molecule, resulting in light absorption in lower energies (the

text: visible spectrum

text: ), which accounts for the characteristic colours of these substances. This and other spectroscopic data for molecules are well explained in MO theory, with an emphasis on electronic states associated with multicenter orbitals, including mixing of orbitals premised on principles of orbital symmetry matching. The same MO principles also naturally explain some electrical phenomena, such as high

text: electrical conductivity

text: in the planar direction of the hexagonal atomic sheets that exist in

text: graphite

text: . This results from continuous band overlap of half-filled p orbitals and explains electrical conduction. MO theory recognizes that some electrons in the graphite atomic sheets are completely

text: delocalized

text: over arbitrary distances, and reside in very large molecular orbitals that cover an entire graphite sheet, and some electrons are thus as free to move and therefore conduct electricity in the sheet plane, as if they resided in a metal.

text: Visible light is an electromagnetic wave, consisting of oscillating electric and magnetic fields traveling through space. The frequency of the wave determines its color:  is red light,  is violet light, and between these (in the range 4-) are all the other colors of the visible spectrum. An electromagnetic wave can have a frequency less than , but it will be invisible to the human eye; such waves are called infrared (IR) radiation. At even lower frequency, the wave is called a microwave, and at still lower frequencies it is called a radio wave. Likewise, an electromagnetic wave can have a frequency higher than , but it will be invisible to the human eye; such waves are called ultraviolet (UV) radiation. Even higher-frequency waves are called X-rays, and higher still are gamma rays.

text: Visible light is an

text: electromagnetic wave

text: , consisting of oscillating

text: electric

text: and

text: magnetic field

text: s traveling through space. The frequency of the wave determines its color:  is red light,  is violet light, and between these (in the range 4-) are all the other colors of the

text: visible spectrum

text: . An electromagnetic wave can have a frequency less than , but it will be invisible to the human eye; such waves are called

text: infrared

text: (IR) radiation. At even lower frequency, the wave is called a

text: microwave

text: , and at still lower frequencies it is called a

text: radio wave

text: . Likewise, an electromagnetic wave can have a frequency higher than , but it will be invisible to the human eye; such waves are called

text: ultraviolet

text: (UV) radiation. Even higher-frequency waves are called

text: X-ray

text: s, and higher still are

text: gamma ray

text: s.

text: Ultraviolet–visible spectroscopy or ultraviolet-visible spectrophotometry (UV-Vis or UV/Vis) refers to absorption spectroscopy or reflectance spectroscopy in the ultraviolet-visible spectral region. This means it uses light in the visible and adjacent (near-UV and near-infrared [NIR]) ranges. The absorption or reflectance in the visible range directly affects the perceived color of the chemicals involved. In this region of the electromagnetic spectrum, atoms and molecules undergo electronic transitions. Absorption spectroscopy is complementary to fluorescence spectroscopy, in that fluorescence deals with transitions from the excited state to the ground state, while absorption measures transitions from the ground state to the excited state.

text: Ultraviolet–visible spectroscopy or ultraviolet-visible spectrophotometry (UV-Vis or UV/Vis) refers to

text: absorption spectroscopy

text: or reflectance spectroscopy in the

text: ultraviolet

text: visible

text: spectral region. This means it uses light in the visible and adjacent (near-UV and

text: near-infrared

text: [NIR]) ranges. The absorption or reflectance in the visible range directly affects the perceived

text: color of the chemicals

text: involved. In this region of the

text: electromagnetic spectrum

text: atoms

text: and

text: molecule

text: s undergo

text: electronic transitions

text: . Absorption spectroscopy is complementary to

text: fluorescence spectroscopy

text: , in that

text: fluorescence

text: deals with transitions from the

text: excited state

text: to the

text: ground state

text: , while absorption measures transitions from the ground state to the excited state.

text: Light–matter interaction in terms of photons is a topic of quantum electrodynamics, and is described in detail by Richard Feynman in his popular book QED: The Strange Theory of Light and Matter.

text: Light–matter interaction in terms of photons is a topic of

text: quantum electrodynamics

text: , and is described in detail by

text: Richard Feynman

text: in his popular book

entity_name: QED: The Strange Theory of Light and Matter

text: QED: The Strange Theory of Light and Matter

text: In 2005, astronomers claimed to have discovered a galaxy made almost entirely of dark matter, 50 million light years away in the Virgo Cluster, which was named VIRGOHI21. Unusually, VIRGOHI21 does not appear to contain visible stars: it was discovered with radio frequency observations of hydrogen. Based on rotation profiles, scientists estimate that this object contains approximately 1000 times more dark matter than hydrogen and has a mass of about 1/10 that of the Milky Way. The Milky Way is estimated to have roughly 10 times as much dark matter as ordinary matter. Models of the Big Bang and structure formation suggested that such dark galaxies should be very common, but VIRGOHI21 was the first to be detected.

text: In 2005, astronomers claimed to have discovered a galaxy made almost entirely of dark matter, 50 million light years away in the

text: Virgo Cluster

text: , which was named

text: . Unusually, VIRGOHI21 does not appear to contain visible stars: it was discovered with radio frequency observations of hydrogen. Based on rotation profiles, scientists estimate that this object contains approximately 1000 times more dark matter than hydrogen and has a mass of about 1/10 that of the Milky Way. The Milky Way is estimated to have roughly 10 times as much dark matter as ordinary matter. Models of the

text: Big Bang

text: and

text: structure formation

text: suggested that such

text: dark galaxies

text: should be very common, but VIRGOHI21 was the first to be detected.

text: In physical optics, light is considered to propagate as a wave. This model predicts phenomena such as interference and diffraction, which are not explained by geometric optics. The speed of light waves in air is approximately 3.0×10 m/s (exactly 299,792,458 m/s in vacuum). The wavelength of visible light waves varies between 400 and 700 nm, but the term "light" is also often applied to infrared (0.7–300 μm) and ultraviolet radiation (10–400 nm).

text: In physical optics, light is considered to propagate as a

text: wave

text: . This model predicts phenomena such as

text: interference

text: and

text: diffraction

text: , which are not explained by geometric optics. The

text: speed of light

text: waves in

text: air

text: is approximately 3.0×10 m/s (exactly 299,792,458 m/s in

text: vacuum

text: ). The

text: wavelength

text: of visible light waves varies between 400 and 700 nm, but the term "light" is also often applied to

text: infrared

text: (0.7–300 μm) and

text: ultraviolet

text: radiation (10–400 nm).

text: The composition of his paintings are composed according to an established pattern: "The upper, narrow part of the canvas shows the back wall or a glass wall through which a garden is visible. A large floor area holds a prominent place. The reality of the building or the world outside is reflected in the floors" The floor area is builds up the according to a special technique: "After the undercoat has been applied and the shadows have been put in, he 'splats' the paint against the canvas: color over color, layer on top of layer - making subtle distinctions in light and dark against the back wall".

text: The

text: composition

text: of his paintings are composed according to an established pattern: "The upper, narrow part of the canvas shows the back wall or a glass wall through which a garden is visible. A large floor area holds a prominent place. The reality of the building or the world outside is reflected in the floors" The floor area is builds up the according to a special technique: "After the undercoat has been applied and the shadows have been put in, he 'splats' the paint against the canvas: color over color, layer on top of layer - making subtle distinctions in light and dark against the back wall".

text: The downside of optical imaging is the lack of penetration depth, especially when working at visible wavelengths.  Depth of penetration is related to the absorption and scattering of light, which is primarily a function of the wavelength of the excitation source. Light is absorbed by endogenous chromophores found in living tissue (e.g. hemoglobin, melanin, and lipids). In general, light absorption and scattering decreases with increasing wavelength. Below ~700 nm (e.g. visible wavelengths), these effects result in shallow penetration depths of only a few millimeters. Thus, in the visible region of the spectrum, only superficial assessment of tissue features is possible. Above 900 nm, water absorption can interfere with signal-to-background ratio. Because the absorption coefficient of tissue is considerably lower in the near infrared (NIR) region (700-900 nm), light can penetrate more deeply, to depths of several centimeters.

text: fNIR is a non-invasive imaging method involving the quantification of chromophore concentration resolved from the measurement of near infrared (NIR) light attenuation, temporal or phasic changes. NIR spectrum light takes advantage of the optical window in which skin, tissue, and bone are mostly transparent to NIR light in the spectrum of 700-900 nm, while hemoglobin (Hb) and deoxygenated-hemoglobin (deoxy-Hb) are stronger absorbers of light. Differences in the absorption spectra of deoxy-Hb and oxy-Hb allow the measurement of relative changes in hemoglobin concentration through the use of light attenuation at multiple wavelengths. Two or more wavelengths are selected, with one wavelength above and one below the isosbestic point of 810 nm at which deoxy-Hb and oxy-Hb have identical absorption coefficients. Using the modified Beer-Lambert law (mBLL), relative concentration can be calculated as a function of total photon path length. Typically the light emitter and detector are placed ipsilaterally on the subjects skull so recorded measurements are due to back-scattered (reflected) light following elliptical pathways.

text: fNIR is a non-invasive imaging method involving the quantification of

text: chromophore

text: concentration resolved from the measurement of near infrared (NIR)

text: light

text: attenuation, temporal or phasic changes. NIR

text: spectrum

text: light takes advantage of the

entity_name: Near-infrared window in biological tissue

text: optical window

text: in which skin, tissue, and bone are mostly transparent to NIR light in the spectrum of 700-900 nm, while

text: hemoglobin

text: (Hb) and deoxygenated-hemoglobin (deoxy-Hb) are stronger absorbers of light. Differences in the absorption spectra of deoxy-Hb and oxy-Hb allow the measurement of relative changes in hemoglobin concentration through the use of light attenuation at multiple

text: wavelength

text: s. Two or more wavelengths are selected, with one wavelength above and one below the

text: isosbestic

text: point of 810 nm at which deoxy-Hb and oxy-Hb have identical absorption

text: coefficient

text: s. Using the modified

text: Beer-Lambert law

text: (mBLL), relative concentration can be calculated as a function of total photon path length. Typically the light emitter and detector are placed ipsilaterally on the subjects skull so recorded measurements are due to back-scattered (reflected) light following elliptical pathways.

text: A triiodide (I) solution formed by mixing iodine and iodide (usually from potassium iodide) is used to test for starch; a dark blue color indicates the presence of starch. The details of this reaction are not yet fully known, but it is thought that the iodine (I and I ions) fit inside the coils of amylose, the charge transfers between the iodine and the starch, and the energy level spacings in the resulting complex correspond to the absorption spectrum in the visible light region. The strength of the resulting blue color depends on the amount of amylose present. Waxy starches with little or no amylose present will color red.

text: A triiodide (I) solution formed by mixing

text: iodine

text: and

text: iodide

text: (usually from

text: potassium iodide

text: ) is used to test for starch; a dark blue color indicates the presence of starch. The details of this reaction are not yet fully known, but it is thought that the iodine (I and I ions) fit inside the coils of

text: amylose

text: , the charge transfers between the iodine and the starch, and the energy level spacings in the resulting complex correspond to the absorption spectrum in the visible light region. The strength of the resulting blue color depends on the amount of amylose present. Waxy starches with little or no amylose present will color red.

text: Under normal conditions due to the transparency of water to visible light photolysis can only occur with a radiation wavelength of 180 nm or shorter. We see then that, assuming a perfect system, the minimum energy input is 6.893 eV.

text: Absorption filters dissipate the energy in unwanted frequencies internally as heat.  This is in contrast to a conventional filter design where the unwanted frequencies are reflected back from the input port of the filter.  Such filters are used where it is undesirable for power to be sent back towards the source.  This is the case with high power transmitters where returning power can be high enough to damage the transmitter.  An absorption filter may be used to remove transmitter spurious emissions such as harmonics or spurious sidebands.  A design that has been in use for some time has slots cut in the walls of the feed waveguide at regular intervals.  This design is known as a leaky-wave filter.  Each slot is connected to a smaller gauge waveguide which is too small to support propagation of frequencies in the wanted band.  Thus those frequencies are unaffected by the filter.  Higher frequencies in the unwanted band, however, readily propagate along the side guides which are terminated with a matched load where the power is absorbed.  These loads are usually a wedge shaped piece of microwave absorbent material.  Another, more compact, design of absorption filter uses resonators with a lossy dielectric.

text: Absorption filters dissipate the energy in unwanted frequencies internally as heat.  This is in contrast to a conventional filter design where the unwanted frequencies are reflected back from the input port of the filter.  Such filters are used where it is undesirable for power to be sent back towards the source.  This is the case with high power transmitters where returning power can be high enough to damage the transmitter.  An absorption filter may be used to remove transmitter

text: spurious emission

text: s such as

text: harmonic

text: s or spurious

text: sideband

text: s.  A design that has been in use for some time has slots cut in the walls of the feed waveguide at regular intervals.  This design is known as a leaky-wave filter.  Each slot is connected to a smaller gauge waveguide which is too small to support propagation of frequencies in the wanted band.  Thus those frequencies are unaffected by the filter.  Higher frequencies in the unwanted band, however, readily propagate along the side guides which are terminated with a matched load where the power is absorbed.  These loads are usually a wedge shaped piece of microwave absorbent material.  Another, more compact, design of absorption filter uses resonators with a lossy dielectric.

text: Gurgen Askaryan (;  or Гурген Аскарян) (December 14, 1928 – 1997) was a prominent Soviet - Armenian physicist, famous for his discovery of the self-focusing of light, pioneering studies of light-matter interactions, and the discovery and investigation of the interaction of high-energy particles with condensed matter. (See Askaryan effect)

text: Gurgen Askaryan (;  or Гурген Аскарян) (December 14, 1928 – 1997) was a prominent

text: Soviet

text: Armenian

text: physicist, famous for his discovery of the

text: self-focusing

text: of light, pioneering studies of light-matter interactions, and the discovery and investigation of the interaction of high-energy particles with condensed matter. (See

text: Askaryan effect

text: Diffuse reflection - Generally, when light strikes the surface of a (non-metallic and non-glassy) solid material, it bounces off in all directions due to multiple reflections by the microscopic irregularities inside the material (e.g., the grain boundaries of a polycrystalline material, or the cell or fiber boundaries of an organic material), and by its surface, if it is rough. Diffuse reflection is typically characterized by omni-directional reflection angles. Most of the objects visible to the naked eye are identified via diffuse reflection. Another term commonly used for this type of reflection is "light scattering". Light scattering from the surfaces of objects is our primary mechanism of physical observation.

text: Diffuse reflection

text: - Generally, when light strikes the surface of a (non-metallic and non-glassy) solid material, it bounces off in all directions due to multiple reflections by the microscopic irregularities inside the material (e.g., the

text: grain boundaries

text: of a

text: polycrystalline

text: material, or the

text: cell

text: or

text: fiber

text: boundaries of an organic material), and by its surface, if it is rough. Diffuse reflection is typically characterized by omni-directional reflection angles. Most of the objects visible to the naked eye are identified via diffuse reflection. Another term commonly used for this type of reflection is "light scattering". Light scattering from the surfaces of objects is our primary mechanism of physical observation.

text: Spectroscopy is the study of light through light-matter interactions.

text: Spectroscopy

text: is the study of light through light-matter interactions.

text: is replaced by a net repulsive density of gravitating matter owed to the presence of primordial drainhole 'tunnels' and continuous creation of new tunnels, each with its excess of repulsion over attraction.  Those drainhole tunnels associated with particles of visible matter provide their gravity; those not tied to visible matter are the unseen 'dark matter'.  'Dark energy' is the net repulsive density of all the drainhole tunnels.  The cosmological model has a 'big bounce' instead of a 'big bang', inflationary acceleration out of the bounce, and a smooth transition to an era of decelerative coasting, followed ultimately by a return to de Sitter-like exponential expansion.

text: Invisible IR light is used in commercial glass fiber communications because it has lower attenuation in such materials than visible light.  However, the glass fibers will transmit visible light somewhat, which is convenient for simple testing of the fibers without requiring expensive equipment.  Splices can be inspected visually, and adjusted for minimal light leakage at the joint, which maximizes light transmission between the ends of the fibers being joined.

text: The 1950s saw the introduction of television to Australia and by 1959 Channel Nine and Channel Seven both commenced broadcasting in Brisbane resulting in Brisbane City Council giving permission for the construction of transmission towers on Mount Coot-tha. Eventually two more towers were constructed for Channel Ten and the Australian Broadcasting Corporation (ABC). The three towers for the commercial television stations, Channel Seven, Channel Nine and Channel Ten, are located on private freehold land along with their respective studio facilities. The fourth tower, used by the ABC, is on land owned by the Brisbane City Council. The towers are highly visible from many parts of Brisbane, even at night as they are mounted with blinking warning lights for aviation purposes. The towers are not included in the entry in the Heritage Register.

text: The 1950s saw the introduction of television to Australia and by 1959

text: Channel Nine

text: and

text: Channel Seven

text: both commenced broadcasting in Brisbane resulting in Brisbane City Council giving permission for the construction of transmission towers on Mount Coot-tha. Eventually two more towers were constructed for

text: Channel Ten

text: and the

text: Australian Broadcasting Corporation

text: (ABC). The three towers for the commercial television stations, Channel Seven, Channel Nine and Channel Ten, are located on private freehold land along with their respective studio facilities. The fourth tower, used by the ABC, is on land owned by the Brisbane City Council. The towers are highly visible from many parts of Brisbane, even at night as they are mounted with blinking warning lights for aviation purposes. The towers are not included in the entry in the Heritage Register.

text: Chromatophores are color pigment changing cells that are directly stimulated by central motor neurons. They are primarily used for quick environmental adaptation for camouflaging. The process of changing the color pigment of their skin relies on a single highly developed chromatophore cell and many muscles, nerves, glail and sheath cells. Chromatophores contract and contain vesicles that stores three different liquid pigments. Each color is indicated by the three types of chromatophore cells: erythrophores, melanophores, and xanthophores. The first type is the erythrophores, which contains reddish pigments such as carotenoids and pteridines. The second type is the melanophores, which contains black and brown pigments such as the melanins. The third type is the xanthophores which contains yellow pigments in the forms of carotenoids. The various colors are made by the combination of the different layers of the chromatophores. These cells are usually located beneath the skin or scale the animals. There are two categories of colors generated by the cell – biochrome and schematochromes. Biochromes are colors chemically formed microscopic, natural pigments. Their chemical composition is created to take in some color of light and reflect the rest. In contrast, schematochromes (structural colors) are colors created by light reflections from a colorless surface and refractions by tissues. Schematochromes act like prisms, refracting and dispersing visible light to the surroundings, which will eventually reflect a specific combination of colors. These categories are determined by the movement of pigments within the chromatophores. The physiological color changes are short-term and fast, found in fishes, and are a result from an animal’s response to a change in the environment. In contrast, the morphological color changes are long-term changes, occurs in different stages of the animal, and are due the change of numbers of chromatophores. To change the color pigments, transparency, or opacity, the cells alter in form and size, and stretch or contract their outer covering.

text: Chromatophore

text: s are color pigment changing cells that are directly stimulated by central motor neurons. They are primarily used for quick environmental adaptation for camouflaging. The process of changing the color pigment of their skin relies on a single highly developed chromatophore cell and many muscles, nerves, glail and sheath cells. Chromatophores contract and contain vesicles that stores three different liquid pigments. Each color is indicated by the three types of chromatophore cells:

text: erythrophores

text: melanophores

text: , and

text: xanthophores

text: . The first type is the erythrophores, which contains reddish pigments such as carotenoids and pteridines. The second type is the melanophores, which contains black and brown pigments such as the melanins. The third type is the xanthophores which contains yellow pigments in the forms of carotenoids. The various colors are made by the combination of the different layers of the chromatophores. These cells are usually located beneath the skin or scale the animals. There are two categories of colors generated by the cell –

text: biochrome

text: and

text: schematochromes

text: . Biochromes are colors chemically formed microscopic, natural pigments. Their chemical composition is created to take in some color of light and reflect the rest. In contrast, schematochromes (structural colors) are colors created by light reflections from a colorless surface and refractions by tissues. Schematochromes act like prisms, refracting and dispersing visible light to the surroundings, which will eventually reflect a specific combination of colors. These categories are determined by the movement of pigments within the chromatophores. The physiological color changes are short-term and fast, found in fishes, and are a result from an animal’s response to a change in the environment. In contrast, the morphological color changes are long-term changes, occurs in different stages of the animal, and are due the change of numbers of chromatophores. To change the color pigments, transparency, or opacity, the cells alter in form and size, and stretch or contract their outer covering.

text: Rapidly brightening objects like novae and supernovae are known to produce a phenomenon known as light echo. The light that travels directly from the object arrives first. If there are clouds of interstellar matter around the star, some light is reflected from the clouds. Because of the longer path, the reflected light arrives later, producing a vision of expanding rings of light around the erupted object. The rings appear to travel faster than the speed of light, but in fact they do not.

text: Rapidly brightening objects like novae and

text: supernova

text: e are known to produce a phenomenon known as

text: light echo

text: . The light that travels directly from the object arrives first. If there are clouds of

text: interstellar matter

text: around the star, some light is reflected from the clouds. Because of the longer path, the reflected light arrives later, producing a vision of expanding rings of light around the erupted object. The rings appear to travel faster than the

text: speed of light

text: , but in fact they do not.

text: The term absorption refers to the physical process of absorbing light, while absorbance does not always measure absorption: it measures attenuation (of transmitted radiant power). Attenuation can be caused by absorption, but also reflection, scattering, and other physical processes.

text: The term

text: absorption

text: refers to the physical process of absorbing light, while absorbance does not always measure absorption: it measures

text: attenuation

text: (of transmitted radiant power). Attenuation can be caused by absorption, but also reflection, scattering, and other physical processes.

text: These Queries, especially the later ones, deal with a wide range of physical phenomena, far transcending any narrow interpretation of the subject matter of "optics." They concern the nature and transmission of heat; the possible cause of gravity; electrical phenomena; the nature of chemical action; the way in which God created matter in "the Beginning;" the proper way to do science; and even the ethical conduct of human beings. These Queries are not really questions in the ordinary sense. They are almost all posed in the negative, as rhetorical questions. That is, Newton does not ask whether light "is" or "may be" a "body." Rather, he declares: "Is not Light a Body?" Not only does this form indicate that Newton had an answer, but that it may go on for many pages. Clearly, as Stephen Hales (a firm Newtonian of the early eighteenth century) declared, this was Newton's mode of explaining "by Query."

text: These Queries, especially the later ones, deal with a wide range of physical phenomena, far transcending any narrow interpretation of the subject matter of "optics." They concern the nature and transmission of

text: heat

text: ; the possible cause of gravity;

text: electrical

text: phenomena; the nature of

text: chemical action

text: ; the way in which God created matter in "the Beginning;" the proper way to do science; and even the

text: ethical

text: conduct of human beings. These Queries are not really questions in the ordinary sense. They are almost all posed in the negative, as

text: rhetorical question

text: s. That is, Newton does not ask whether light "is" or "may be" a "body." Rather, he declares: "Is not Light a Body?" Not only does this form indicate that Newton had an answer, but that it may go on for many pages. Clearly, as

text: Stephen Hales

text: (a firm Newtonian of the early eighteenth century) declared, this was Newton's mode of explaining "by Query."

text: Optical measuring instruments that work with monochromatic light, such as spectrophotometers, define stray light as light in the system at wavelengths (colors) other than the one intended. The stray light level is one of the most critical specifications of an instrument. For instance, intense, narrow absorption bands can easily appear to have a peak absorption less than the true absorption of the sample because the ability of the instrument to measure light transmission through the sample is limited by the stray light level. One method to reduce stray light in these systems is the use of double monochromators. The ratio of transmitted stray light to signal is reduced to the product of the ratio for each monochromator, so combining two monochromators in series with 10 stray light each produces a system with a stray light ratio of 10, allowing a much larger dynamic range for measurements.

text: Optical measuring instruments that work with

text: monochromatic light

text: , such as

text: spectrophotometer

text: s, define stray light as light in the system at

text: wavelength

text: s (colors) other than the one intended. The stray light level is one of the most critical specifications of an instrument. For instance, intense, narrow absorption bands can easily appear to have a peak absorption less than the true absorption of the sample because the ability of the instrument to measure light transmission through the sample is limited by the stray light level. One method to reduce stray light in these systems is the use of

text: double monochromator

text: s. The ratio of transmitted stray light to signal is reduced to the product of the ratio for each monochromator, so combining two monochromators in series with 10 stray light each produces a system with a stray light ratio of 10, allowing a much larger dynamic range for measurements.

text: Snowfall intensity is classified in terms of visibility. When the visibility is over , snow is determined to be light. Moderate snow describes snowfall with visibility restrictions between  and . Heavy snowfall describes conditions when visibility is restricted below .

text: Snowfall intensity is classified in terms of

text: visibility

text: . When the visibility is over , snow is determined to be light. Moderate snow describes snowfall with visibility restrictions between  and . Heavy snowfall describes conditions when visibility is restricted below .

text: Pi Herculis (π Her, π Herculis) is a third-magnitude star in the constellation Hercules. As one of the four stars in the Keystone asterism (see yellow quadrangle) is one of the more easily recognized in the constellation. It has an apparent visual magnitude of +3.2, which is visible to the naked eye and makes it one of the brighter members of the constellation. The Hipparcos satellite mission estimated its distance at roughly 115 parsecs from Earth, or about 377 light years away. The overall reduction in the star's visual magnitude due to extinction from the intervening matter is 0.11.

text: Pi Herculis (π Her, π Herculis) is a third-magnitude

text: star

text: in the

text: constellation

text: Hercules

text: . As one of the four stars in the

text: Keystone

text: asterism

text: (see yellow

text: quadrangle

text: ) is one of the more easily recognized in the constellation. It has an

text: apparent visual magnitude

text: of +3.2, which is visible to the naked eye and makes it one of the brighter members of the constellation. The

text: Hipparcos

text: satellite

text: mission estimated its distance at roughly 115

text: parsec

text: s from Earth, or about 377

text: light year

text: s away. The overall reduction in the star's visual magnitude due to

text: extinction

text: from the intervening matter is 0.11.

text: light will pass through that polarizer with no absorption whatsoever.

text: Plasmons play a large role in the optical properties of metals and semiconductors. Light of frequencies below the plasma frequency is reflected by a material because the electrons in the material screen the electric field of the light. Light of frequencies above the plasma frequency is transmitted by a material because the electrons in the material cannot respond fast enough to screen it. In most metals, the plasma frequency is in the ultraviolet, making them shiny (reflective) in the visible range. Some metals, such as copper and gold, have electronic interband transitions in the visible range, whereby specific light energies (colors) are absorbed, yielding their distinct color. In semiconductors, the valence electron plasmon frequency is usually in the deep ultraviolet, while their electronic interband transitions are in the visible range, whereby specific light energies (colors) are absorbed, yielding their distinct color which is why they are reflective. It has been shown that the plasmon frequency may occur in the mid-infrared and near-infrared region when semiconductors are in the form of nanoparticles with heavy doping.

text: Plasmons play a large role in the

text: optical

text: properties of

text: metal

text: s and semiconductors.

text: Light

text: of frequencies below the

text: plasma frequency

text: is

text: reflected

text: by a material because the electrons in the material

text: screen

text: the

text: electric field

text: of the light. Light of frequencies above the plasma frequency is transmitted by a material because the electrons in the material cannot respond fast enough to screen it. In most metals, the plasma frequency is in the

text: ultraviolet

text: , making them shiny (reflective) in the visible range. Some metals, such as

text: copper

text: and

text: gold

text: , have electronic interband transitions in the visible range, whereby specific light energies (colors) are absorbed, yielding their distinct color. In

text: semiconductor

text: s, the

text: valence electron

text: plasmon frequency is usually in the deep ultraviolet, while their electronic interband transitions are in the visible range, whereby specific light energies (colors) are absorbed, yielding their distinct color which is why they are reflective. It has been shown that the plasmon frequency may occur in the mid-infrared and near-infrared region when semiconductors are in the form of nanoparticles with heavy doping.

text: Dayanand explains that the God Brahman is the Nimita Karan of this universe and the latter (the universe or the matter) is denoted as Upadan Karan, which means that the visible universe exists in a non-visual form that is used by Brahman to create the (visible) universe. The first things (elements) created were Sat-Raj-Tam, which were in turn used to create all the rest. It is said that all of matter is a mixtures of these three elements. When these three elements are combined, the state of that matter is termed Mahat.

text: Dayanand explains that the God

text: Brahman

text: is the Nimita Karan of this universe and the latter (the universe or the matter) is denoted as Upadan Karan, which means that the visible universe exists in a non-visual form that is used by Brahman to create the (visible) universe. The first things (elements) created were Sat-Raj-Tam, which were in turn used to create all the rest. It is said that all of matter is a mixtures of these three elements. When these three elements are combined, the state of that matter is termed Mahat.

text: There is a deep sleep state, states the Upanishad, where impressions end and the mind too sleeps without impressions, and this is the complete state of mind relaxation, of body happiness. It is then when everything in a person retires into Atman-Brahman, including the matter and elements of matter, water and elements of water, light and elements of light, eye and what is visible, ear and what is audible, smell and the objects of smell, taste and objects of taste, touch and objects of touch, speech and objects of speech, sexuality and objects of its enjoyment, feet and what is moveable, hands and what is seizable, mind and the objects of mind, thought and objects of thought, reason and objects of reason, self-consciousness and objects of self-consciousness, insight and objects of illumination, life-force and object of life-force.

text: Operetta is a genre of light opera, light in terms both of music and subject matter.

text: Operetta is a genre of light

text: opera

text: , light in terms both of music and subject matter.

text: There is, however, the crucial detail that Lykaios or Lykeios (epithets of Zeus and Apollo) may derive from Proto-Greek *λύκη, "light", a noun still attested in compounds such as ἀμφιλύκη, "twilight", λυκάβας, "year" (lit. "light's course") etc. This, Cook argues, brings indeed much new 'light' to the matter as Achaeus, the contemporary tragedian of Sophocles, spoke of Zeus Lykaios as "starry-eyed", and this Zeus Lykaios may just be the Arcadian Zeus, son of Aether, described by Cicero. Again under this new signification may be seen Pausanias' descriptions of Lykosoura being 'the first city that ever the sun beheld', and of the altar of Zeus, at the summit of Mount Lykaion, before which stood two columns bearing gilded eagles and 'facing the sun-rise'. Further Cook sees only the tale of Zeus' sacred precinct at Mount Lykaion allowing no shadows referring to Zeus as 'god of light' (Lykaios).

text: There is, however, the crucial detail that Lykaios or Lykeios (epithets of Zeus and Apollo) may derive from

text: Proto-Greek

text: *λύκη, "light", a noun still attested in compounds such as ἀμφιλύκη, "twilight", λυκάβας, "year" (lit. "light's course") etc. This, Cook argues, brings indeed much new 'light' to the matter as

text: Achaeus

text: , the contemporary tragedian of

text: Sophocles

text: , spoke of Zeus Lykaios as "starry-eyed", and this Zeus Lykaios may just be the Arcadian Zeus, son of Aether, described by

text: Cicero

text: . Again under this new signification may be seen

text: Pausanias

text: ' descriptions of Lykosoura being 'the first city that ever the sun beheld', and of the altar of Zeus, at the summit of Mount Lykaion, before which stood two columns bearing gilded eagles and 'facing the sun-rise'. Further Cook sees only the tale of Zeus' sacred precinct at Mount Lykaion allowing no shadows referring to Zeus as 'god of light' (Lykaios).

text: The intern understood that the light being would now become completely incorporeal, and undertake at last a final battle with its nemesis near Algol. Joe Slater died then, and there were no further transmissions. That night an enormously bright star was discovered in the sky near Algol. Within a week it had dimmed to the luminosity of an ordinary star and in a few months it had become barely visible to the naked eye.

text: The intern understood that the light being would now become completely incorporeal, and undertake at last a final battle with its nemesis near

text: Algol

text: . Joe Slater died then, and there were no further transmissions. That night an

text: enormously bright star

text: was discovered in the sky near Algol. Within a week it had dimmed to the luminosity of an ordinary star and in a few months it had become barely visible to the naked eye.

text: A further internal diagonal passes through the space occupied by the Infanta. There is a similar connection between the female dwarf and the figure of Velázquez himself, both of whom look towards the viewer from similar angles, creating a visual tension. The face of Velázquez is dimly lit by light that is reflected, rather than direct. For this reason his features, though not as sharply defined, are more visible than those of the dwarf who is much nearer the light source. This appearance of a total face, full-on to the viewer, draws the attention, and its importance is marked, tonally, by the contrasting frame of dark hair, the light on the hand and brush, and the skilfully placed triangle of light on the artist's sleeve, pointing directly to the face.

text: The new spectrophotometers used a prism to separate light into its absorption spectrum and a phototube to electrically measure the light energy across the spectrum. They allowed the user to plot the light absorption spectrum of a substance, giving a standardized "fingerprint", characteristic of a compound. With Beckman's model D, later known as the DU spectrophotometer, National Technical Laboratories successfully provided the first easy-to-use single instrument containing both the optical and electronic components needed for ultraviolet-absorption spectrophotometry. The user could insert a sample, dial up the desired wavelength of light, and read the amount of absorption of that frequency from a simple meter.  It produced accurate absorption spectra in both the ultraviolet and the visible regions of the spectrum with relative ease and repeatable accuracy.  The National Bureau of Standards ran tests to certify that the DU's results were accurate and repeatable and recommended its use.

text: The new spectrophotometers used a prism to separate light into its absorption spectrum and a phototube to electrically measure the light energy across the spectrum. They allowed the user to plot the light absorption spectrum of a substance, giving a standardized "fingerprint", characteristic of a compound. With Beckman's model D, later known as the DU spectrophotometer, National Technical Laboratories successfully provided the first easy-to-use single instrument containing both the optical and electronic components needed for

text: ultraviolet-absorption spectrophotometry

text: . The user could insert a sample, dial up the desired wavelength of light, and read the amount of absorption of that frequency from a simple meter.  It produced accurate absorption spectra in both the ultraviolet and the visible regions of the spectrum with relative ease and repeatable accuracy.  The National Bureau of Standards ran tests to certify that the DU's results were accurate and repeatable and recommended its use.

text: While the dark field image may first appear to be a negative of the bright field image, different effects are visible in each. In bright field microscopy, features are visible where either a shadow is cast on the surface by the incident light, or a part of the surface is less reflective, possibly by the presence of pits or scratches. Raised features that are too smooth to cast shadows will not appear in bright field images, but the light that reflects off the sides of the feature will be visible in the dark field images.

text: For the simplified scenario of visible light travelling from air (n ≈ 1.0) into common glass (), value of R is 0.04, or 4%, on a single reflection. So at most 96% of the light ( 1 − R  0.96}}) actually enters the glass, and the rest is reflected from the surface. The amount of light reflected is known as the reflection loss.

text: Jung drew an analogy between the psyche and light on the electromagnetic spectrum. The center of the visible light spectrum (i.e., yellow) corresponds to consciousness, which grades into unconsciousnessness at the red and blue ends. Red corresponds to basic unconscious urges, and the invisible infra-red end of the spectrum corresponds to the influence of biological instinct, which merges with its chemical and physical conditions. The blue end of the spectrum represents spiritual ideas; and the archetypes, exerting their influence from beyond the visible, correspond to the invisible realm of ultra-violet. Jung suggested that not only do the archetypal structures govern the behavior of all living organisms, but that they were contiguous with structures controlling the behavior of inorganic matter as well.

text: Jung drew an analogy between the psyche and

text: light

text: on the

text: electromagnetic spectrum

text: . The center of the visible light spectrum (i.e., yellow) corresponds to consciousness, which grades into unconsciousnessness at the red and blue ends. Red corresponds to basic unconscious urges, and the invisible infra-red end of the spectrum corresponds to the influence of biological

text: instinct

text: , which merges with its chemical and physical conditions. The blue end of the spectrum represents spiritual ideas; and the archetypes, exerting their influence from beyond the visible, correspond to the invisible realm of ultra-violet. Jung suggested that not only do the archetypal structures govern the behavior of all living organisms, but that they were contiguous with structures controlling the behavior of inorganic matter as well.

text: Specular reflection is the mirror-like reflection of light (or of other kinds of wave) from a surface, in which light from a single incoming direction (a ray) is reflected into a single outgoing direction.  Such behavior is described by the law of reflection, which states that the direction of incoming light (the incident ray), and the direction of outgoing light reflected (the reflected ray) make the same angle with respect to the surface normal, thus the angle of incidence equals the angle of reflection (

text: Specular reflection is the

text: mirror

text: -like

text: reflection

text: of

text: light

text: (or of other kinds of

text: wave

text: ) from a surface, in which light from a single incoming direction (a

text: ray

text: ) is reflected into a single outgoing direction.  Such behavior is described by the law of reflection, which states that the direction of incoming light (the incident ray), and the direction of outgoing light reflected (the reflected ray) make the same angle with respect to the

text: surface normal

text: , thus the angle of incidence equals the angle of reflection (

text: Materials which do not transmit light are called opaque. Many such substances have a chemical composition which includes what are referred to as absorption centers. Many substances are selective in their absorption of white light frequencies. They absorb certain portions of the visible spectrum while reflecting others. The frequencies of the spectrum which are not absorbed are either reflected or transmitted for our physical observation. This is what gives rise to color. The attenuation of light of all frequencies and wavelengths is due to the combined mechanisms of absorption and scattering.

text: Materials which do not

text: transmit

text: light are called

text: opaque

text: . Many such substances have a

text: chemical composition

text: which includes what are referred to as

text: absorption

text: centers. Many substances are selective in their absorption of

text: white light

text: frequencies

text: . They absorb certain portions of the

text: visible spectrum

text: while reflecting others. The frequencies of the spectrum which are not absorbed are either reflected or transmitted for our physical observation. This is what gives rise to

text: color

text: . The attenuation of light of all frequencies and wavelengths is due to the combined mechanisms of absorption and

text: scattering

text: The Source Four is the first ERS to use a faceted borosilicate reflector behind the lamp.  Nearly all stage lights have some form of reflector positioned behind the lamp to reflect otherwise wasted light out of the front of the instrument.  The Source Four's reflector is dichroic, meaning that it reflects light of only certain wavelengths.  The Source Four's reflector reflects back 95% of the visible light striking it, while allowing over 90% of the infrared radiation (heat) to pass out the back of the instrument. This produces a much cooler light which is less destructive to gobos or color gels at the front of the fixture, and reduces localized heating of the lighting target.

text: The Source Four is the first ERS to use a faceted

text: borosilicate

text: reflector behind the lamp.  Nearly all

text: stage lights

text: have some form of reflector positioned behind the lamp to reflect otherwise wasted light out of the front of the instrument.  The Source Four's reflector is

text: dichroic

text: , meaning that it reflects

text: light

text: of only certain wavelengths.  The Source Four's reflector reflects back 95% of the visible light striking it, while allowing over 90% of the

text: infrared

text: radiation (heat) to pass out the back of the instrument. This produces a much cooler light which is less destructive to

text: gobo

text: s or

text: color gel

text: s at the front of the fixture, and reduces localized heating of the lighting target.

text: Some authors, as in this article, use the term chromosome in a wider sense, to refer to the individualized portions of chromatin in cells, either visible or not under light microscopy. However, others use the concept in a narrower sense, to refer to the individualized portions of chromatin during cell division, visible under light microscopy due to high condensation.

text: On the basis of its absolute magnitude in the visible light spectrum and supposed albedo (which usually varies from 0.05 to 0.25 for the main-belt asteroids) its diameter could be anywhere between 3 and 6 kilometers. Since asteroids in the inner main-belt are typically of a silicaceous rather than of a carbonaceous composition, with albedos around 0.20, the body's diameter might be on the lower end of NASA's published conversion table, as the higher the reflectivity (albedo), the smaller the body's diameter for the given absolute magnitude of 15.0.

text: On the basis of its absolute

text: magnitude

text: in the visible

text: light spectrum

text: and supposed

text: albedo

text: (which usually varies from 0.05 to 0.25 for the main-belt asteroids) its diameter could be anywhere between 3 and 6 kilometers. Since asteroids in the inner main-belt are typically of a

text: silicaceous

text: rather than of a

text: carbonaceous

text: composition, with albedos around 0.20, the body's diameter might be on the lower end of NASA's published conversion table, as the higher the reflectivity (albedo), the smaller the body's diameter for the given absolute magnitude of 15.0.

text: Complicating matters is that the composition of the food eaten (see glycemic index) affects intestinal absorption rates. Glucose from some foods is absorbed more (or less) rapidly than the same amount of glucose in other foods. In addition, fats and proteins cause delays in absorption of glucose from carbohydrates eaten at the same time. As well, exercise reduces the need for insulin even when all other factors remain the same, since working muscle has some ability to take up glucose without the help of insulin.

text: Complicating matters is that the composition of the food eaten (see

text: glycemic index

text: ) affects intestinal absorption rates. Glucose from some foods is absorbed more (or less) rapidly than the same amount of glucose in other foods. In addition, fats and proteins cause delays in absorption of glucose from carbohydrates eaten at the same time. As well, exercise reduces the need for insulin even when all other factors remain the same, since working muscle has some ability to take up glucose without the help of insulin.

text: Both medical CT and OPT compute 3D volumes based on transmission of the photon through the material of interest. Given that the tissue is typically opaque in the ultraviolet, visible, and near-infrared spectrum, the tissue must first be made clear with an optical clearing agent, so that the light can pass through. Common optical clearing agents include BABB and methyl salicylate (wintergreen).

text: In the author’s opinion, these are fantastic grounds for deviation into abstract, non-material, non-objective matter; confrontation of photography with the essential and most basic constitutional matter, Light. This is the reason why his project, based on introspection of sublime light, elevation from darkness into the light, and spiritual absorption, a voyage that is traced by light, could be handled and tracked by photography and its basic tool, Light.

text: The central star, a source of infrared radiation usually referred to as S106 IR or S106 IRS 4, is believed to have been formed only 100,000 years ago.  It is a massive star, approximately 15 solar masses.  Two jets of matter streaming from its poles heat surrounding matter to a temperature of around 10,000 °C.  Dust that is not ionized by the star's jets reflect light from the star.  With an estimated surface temperature of 37,000°K, it is classified as a type O8 star.  It loses around 10  per year in solar winds, ejecting material at around 100 km/s.

text: The central star, a source of infrared radiation usually referred to as S106 IR or S106 IRS 4, is believed to have been formed only 100,000 years ago.  It is a massive star, approximately 15 solar masses.  Two jets of matter streaming from its poles heat surrounding matter to a temperature of around 10,000 °C.  Dust that is not ionized by the star's jets reflect light from the star.  With an estimated surface temperature of 37,000°K, it is classified as a

text: type O8

text: star.  It loses around 10

text: per year in solar winds, ejecting material at around 100 km/s.

text: It is dominated by millions of bright stars and dark dust, in spiral arms rotating about the center.  Open clusters containing bright blue stars are sprinkled along these spiral arms, with dark lanes of dense interstellar dust between.  Less visible are dim normal stars and interstellar gas, producing such high mass that they dominate the dynamics of the inner galaxy. Not visible is matter of unknown form called dark matter, needed to explain the motions of the visible material in the outer galaxy. The galaxy is approximately 200,000 light-years across, in between the sizes of the Andromeda Galaxy and our home galaxy, the Milky Way.

text: It is dominated by millions of bright stars and dark dust, in

text: spiral arm

text: s rotating about the center.

text: Open cluster

text: s containing bright

text: blue stars

text: are sprinkled along these spiral arms, with dark lanes of dense interstellar dust between.  Less visible are dim normal stars and

text: interstellar gas

text: , producing such high mass that they dominate the dynamics of the inner galaxy. Not visible is matter of unknown form called

text: dark matter

text: , needed to explain the motions of the visible material in the outer galaxy. The galaxy is approximately 200,000 light-years across, in between the sizes of the

text: Andromeda Galaxy

text: and our home galaxy, the

text: Milky Way

text: In geometrical optics, a caustic is the envelope of a family of light rays. In this picture there is an arc of a circle. The light rays (shown in blue) are coming from a source at infinity, and so arrive parallel. When they hit the circular arc the light rays are scattered in different directions according to the law of reflection. When a light ray hits the arc at a point the light will be reflected as though it had been reflected by the arc's tangent line at that point. The reflected light rays give a one-parameter family of lines in the plane. The envelope of these lines is the reflective caustic. A reflective caustic will generically consist of smooth points and ordinary cusp points.

text: In

text: geometrical optics

text: , a

text: caustic

text: is the envelope of a family of

text: light rays

text: . In this picture there is an

text: arc

text: of a circle. The light rays (shown in blue) are coming from a source at infinity, and so arrive parallel. When they hit the circular arc the light rays are scattered in different directions according to the

text: law of reflection

text: . When a light ray hits the arc at a point the light will be reflected as though it had been reflected by the arc's

text: tangent line

text: at that point. The reflected light rays give a one-parameter family of lines in the plane. The envelope of these lines is the

text: reflective caustic

text: . A reflective caustic will generically consist of

text: smooth

text: points and

text: ordinary cusp

text: points.

text: The term "reflection" is sometimes used for a larger class of mappings from a Euclidean space to itself, namely the non-identity isometries that are involutions. Such isometries have a set of fixed points (the "mirror") that is an affine subspace, but is possibly smaller than a hyperplane. For instance a reflection through a point is an involutive isometry with just one fixed point; the image of the letter p under itwould look like a d. This operation is also known as a central inversion , and exhibits Euclidean space as a symmetric space. In a Euclidean vector space, the reflection in the point situated at the origin is the same as vector negation. Other examples include reflections in a line in three-dimensional space. Typically, however, unqualified use of the term "reflection" means reflection in a hyperplane.

text: The term "reflection" is sometimes used for a larger class of mappings from a Euclidean space to itself, namely the non-identity isometries that are involutions. Such isometries have a set of fixed points (the "mirror") that is an

text: affine subspace

text: , but is possibly smaller than a hyperplane. For instance a

text: reflection through a point

text: is an involutive isometry with just one fixed point; the image of the letter p under itwould look like a d. This operation is also known as a

text: central inversion

text: , and exhibits Euclidean space as a

text: symmetric space

text: . In a

text: Euclidean vector space

text: , the reflection in the point situated at the origin is the same as vector negation. Other examples include reflections in a line in three-dimensional space. Typically, however, unqualified use of the term "reflection" means reflection in a

text: hyperplane

text: Few materials do not cause diffuse reflection: among these are metals, which do not allow light to enter; gases, liquids, glass, and transparent plastics (which have a liquid-like amorphous microscopic structure); single crystals, such as some gems or a salt crystal; and some very special materials, such as the tissues which make the cornea and the lens of an eye. These materials can reflect diffusely, however, if their surface is microscopically rough, like in a frost glass (Figure 2), or, of course, if their homogeneous structure deteriorates, as in cataracts of the eye lens.

text: Few materials do not cause diffuse reflection: among these are metals, which do not allow light to enter; gases, liquids, glass, and transparent plastics (which have a liquid-like

text: amorphous

text: microscopic structure);

text: single crystals

text: , such as some gems or a salt crystal; and some very special materials, such as the tissues which make the

text: cornea

text: and the

text: lens

text: of an eye. These materials can reflect diffusely, however, if their surface is microscopically rough, like in a

text: frost glass

text: (Figure 2), or, of course, if their homogeneous structure deteriorates, as in

text: cataract

text: s of the eye lens.

text: Points are scored by knocking the opponent out, down to the floor, by sweep and controlled follow-up for half a point, or by otherwise visibly incapacitating them. Unless there is a knockdown or sweep, the bout is continuous, with stoppages only to break up locked clinches or if the fighters leave the fight area. Unlike American full-contact karate, or point karate, clean hits are not counted in and by themselves, as the scoring depends entirely on the effect of the hits, not on the formal or stylistic appearance of the techniques. No matter the perfection in execution of a technique, it will not score unless it visibly affects the opponent. In the same manner, if a technique does show a visible effect, it does not matter if it is executed in a manner regarded as inferior.

text: The inspector will use visible light with adequate intensity (100 foot-candles or 1100 lux is typical) for visible dye penetrant. Ultraviolet (UV-A) radiation of adequate intensity (1,000 micro-watts per centimeter squared is common), along with low ambient light levels (less than 2 foot-candles) for fluorescent penetrant examinations.  Inspection of the test surface should take place after 10- to 30-minute development time, depends of product kind.  This time delay allows the blotting action to occur.  The inspector may observe the sample for indication formation when using visible dye.  It is also good practice to observe indications as they form because the characteristics of the bleed out are a significant part of interpretation characterization of flaws.

text: The inspector will use visible light with adequate intensity (100

text: foot-candles

text: or 1100

text: lux

text: is typical) for visible dye penetrant. Ultraviolet (UV-A) radiation of adequate intensity (1,000 micro-watts per centimeter squared is common), along with low ambient light levels (less than 2 foot-candles) for fluorescent penetrant examinations.  Inspection of the test surface should take place after 10- to 30-minute development time, depends of product kind.  This time delay allows the blotting action to occur.  The inspector may observe the sample for indication formation when using visible dye.  It is also good practice to observe indications as they form because the characteristics of the bleed out are a significant part of interpretation characterization of flaws.

text: The precision to which a parabolic dish must be made in order to focus energy well depends on the wavelength of the energy. If the dish is wrong by a quarter of a wavelength, then the reflected energy will be wrong by a half wavelength, which means that it will interfere destructively with energy that has been reflected properly from another part of the dish. To prevent this, the dish must be made correctly to within about  of a wavelength. The wavelength range of visible light is between about 400 and 700 nanometres (nm), so in order to focus all visible light well, a reflector must be correct to within about 20 nm. For comparison, the diameter of a human hair is usually about 50,000 nm, so the required accuracy for a reflector to focus visible light is about 2500 times less than the diameter of a hair. For example, the flaw in the Hubble Space Telescope mirror (too flat by about 2,200 nm at its perimeter) caused severe spherical aberration until corrected with COSTAR.

text: The precision to which a parabolic dish must be made in order to focus energy well depends on the wavelength of the energy. If the dish is wrong by a quarter of a wavelength, then the reflected energy will be wrong by a half wavelength, which means that it will interfere destructively with energy that has been reflected properly from another part of the dish. To prevent this, the dish must be made correctly to within about  of a wavelength. The wavelength range of visible light is between about 400 and 700 nanometres (nm), so in order to focus all visible light well, a reflector must be correct to within about 20 nm. For comparison, the diameter of a human hair is usually about 50,000 nm, so the required accuracy for a reflector to focus visible light is about 2500 times less than the diameter of a hair. For example, the flaw in the

text: Hubble Space Telescope

text: mirror (too flat by about 2,200 nm at its perimeter) caused severe

text: spherical aberration

text: until corrected with

entity_name: Corrective Optics Space Telescope Axial Replacement

text: COSTAR

text: Large-Scale Structure of Baryonic Matter: With its high FUV spectroscopic sensitivity, COS uniquely suited for exploring the Lyman-alpha forest. This is the ‘forest’ of absorption spectra seen in the spectra of distant galaxies and quasars caused by intergalactic gas clouds, which may contain the majority of baryonic matter in the universe. Because the most useful absorption lines for these observations are in the far ultraviolet and the sources are faint, a high sensitivity FUV spectrograph with wide wavelength coverage is needed to perform these observations. By determining the redshift and line width of the intervening absorbers, COS will be able to map out the temperature, density and composition of dark baryonic matter in the Cosmic Web.

text: Large-Scale Structure of

text: Baryonic Matter

text: : With its high FUV spectroscopic sensitivity, COS uniquely suited for exploring the

text: Lyman-alpha forest

text: . This is the ‘forest’ of

text: absorption spectra

text: seen in the spectra of distant

text: galaxies

text: and

text: quasars

text: caused by intergalactic gas clouds, which may contain the majority of baryonic matter in the universe. Because the most useful absorption lines for these observations are in the far ultraviolet and the sources are faint, a high sensitivity FUV spectrograph with wide wavelength coverage is needed to perform these observations. By determining the

text: redshift

text: and line width of the intervening absorbers, COS will be able to map out the temperature, density and composition of dark

text: baryonic matter

text: in the

text: Cosmic Web

text: In strict mathematical terms, it may be impossible to define such a path, along which matter can travel. However, it usually is possible to find an infinite sequence of paths that converge uniformly to some limit, that is, some "limiting" path. Of course, under relativity, matter may not be able to travel along this limiting path, but light can travel along this path. In fact, the path of the light beam from A to B is the theoretical limit. No ship in normal space could follow the path of light in 4-D space time, but it can get arbitrarily close (until the energy required to go any faster exceeds the energy available).

text: The pleochroic colours are at their maximum when light is polarized parallel with a crystallographic axis. The axes are designated X, Y and Z. These axes can be determined from the appearance of a crystal in a conoscopic interference pattern. Where there are two optical axes, the acute bisection of the axes gives Z for positive minerals and X for negative minerals and the obtuse bisection give the alternative axis (X or Z). Perpendicular to these is the Y axis. The colour is measured with the polarization parallel to each direction. An absorption formula records the amount of absorption parallel to each axis in the form of X < Y < Z with the left most having the least absorption and the rightmost the most.

text: The pleochroic colours are at their maximum when light is polarized parallel with a

text: crystallographic axis

text: . The axes are designated X, Y and Z. These axes can be determined from the appearance of a crystal in a

text: conoscopic interference pattern

text: . Where there are two optical axes, the acute bisection of the axes gives Z for positive minerals and X for negative minerals and the obtuse bisection give the alternative axis (X or Z). Perpendicular to these is the Y axis. The colour is measured with the polarization parallel to each direction. An absorption formula records the amount of absorption parallel to each axis in the form of X < Y < Z with the left most having the least absorption and the rightmost the most.

text: In Egarosindur, many pious and kind religious leader came here for inviting people into the light of Islam.Some of them named-Fakir Garibullah Shah (RH), Syed Ahmed Rumi (RH), Nigrin shah(RH) and so on. Their mazars are situated in this village. The Mazar of Garibullah shah(RH) is in a hill like higher position.People treat their mazar with great respect. But it is a matter of great pleasure that there are no superstitions and fanatic activities because the villagers are very much conscious about this matter.

text: In Egarosindur, many pious and kind religious leader came here for inviting people into the light of Islam.Some of them named-Fakir Garibullah Shah (RH), Syed Ahmed Rumi (RH), Nigrin shah(RH) and so on. Their

text: mazar

text: s are situated in this village. The Mazar of Garibullah shah(RH) is in a hill like higher position.People treat their mazar with great respect. But it is a matter of great pleasure that there are no superstitions and fanatic activities because the villagers are very much conscious about this matter.

text: Painters depicting someone gazing into a mirror often also show the person's reflection. This is a kind of abstraction—in most cases the angle of view is such that the person's reflection should not be visible. Similarly, in movies and still photography an actor or actress is often shown ostensibly looking at him- or herself in the mirror, and yet the reflection faces the camera. In reality, the actor or actress sees only the camera and its operator in this case, not their own reflection.

text: Painters depicting someone gazing into a mirror often also show the person's reflection. This is a kind of abstraction—in most cases the angle of view is such that the person's reflection should not be visible. Similarly, in movies and

text: still photography

text: an actor or actress is often shown ostensibly looking at him- or herself in the mirror, and yet the reflection faces the camera. In reality, the actor or actress sees only the camera and its operator in this case, not their own reflection.

text: Colloidal crystals have found application in optics as photonic crystals. Photonics is the science of generating, controlling, and detecting photons (packets of light), particularly in the visible and near Infrared, but also extending to the Ultraviolet, Infrared and far IR portions of the electromagnetic spectrum. The science of photonics includes the emission, transmission, amplification, detection, modulation, and switching of lightwaves over a broad range of frequencies and wavelengths. Photonic devices include electro-optic components such as lasers (Light Amplification by Stimulated Emission of Radiation) and optical fiber. Applications include telecommunications, information processing, illumination, spectroscopy, holography, medicine (surgery, vision correction, endoscopy), military (guided missile) technology, agriculture and robotics.

text: Colloidal crystals have found application in

text: optics

text: as

text: photonic crystals

text: Photonics

text: is the science of generating, controlling, and detecting

text: photons

text: (packets of light), particularly in the visible and near

text: Infrared

text: , but also extending to the

text: Ultraviolet

text: , Infrared and far IR portions of the

text: electromagnetic spectrum

text: . The science of photonics includes the

text: emission

text: transmission

text: , amplification, detection,

text: modulation

text: , and switching of lightwaves over a broad range of

text: frequencies

text: and

text: wavelengths

text: . Photonic devices include

text: electro-optic

text: components such as

text: lasers

text: (Light Amplification by Stimulated Emission of

text: Radiation

text: ) and

text: optical fiber

text: . Applications include

text: telecommunications

text: , information processing, illumination,

text: spectroscopy

text: holography

text: medicine

text: surgery

text: , vision correction,

text: endoscopy

text: military

text: (guided

text: missile

text: technology

text: agriculture

text: and

text: robotics

text: Reflections can be divided into two types: specular reflection and diffuse reflection. Specular reflection describes the gloss of surfaces such as mirrors, which reflect light in a simple, predictable way. This allows for production of reflected images that can be associated with an actual (real) or extrapolated (virtual) location in space. Diffuse reflection describes non-glossy materials, such as paper or rock. The reflections from these surfaces can only be described statistically, with the exact distribution of the reflected light depending on the microscopic structure of the material. Many diffuse reflectors are described or can be approximated by Lambert's cosine law, which describes surfaces that have equal luminance when viewed from any angle. Glossy surfaces can give both specular and diffuse reflection.

text: Reflections can be divided into two types:

text: specular reflection

text: and

text: diffuse reflection

text: . Specular reflection describes the gloss of surfaces such as mirrors, which reflect light in a simple, predictable way. This allows for production of reflected images that can be associated with an actual (

text: real

text: ) or extrapolated (

text: virtual

text: ) location in space. Diffuse reflection describes non-glossy materials, such as paper or rock. The reflections from these surfaces can only be described statistically, with the exact distribution of the reflected light depending on the microscopic structure of the material. Many diffuse reflectors are described or can be approximated by

text: Lambert's cosine law

text: , which describes surfaces that have equal

text: luminance

text: when viewed from any angle. Glossy surfaces can give both specular and diffuse reflection.

text: Dark matter is an unidentified type of matter comprising approximately 27% of the mass and energy in the observable universe that is not accounted for by dark energy, baryonic matter (ordinary matter), and neutrinos. The name refers to the fact that it does not emit or interact with electromagnetic radiation, such as light, and is thus invisible to the entire electromagnetic spectrum. Although dark matter has not been directly observed, its existence and properties are inferred from its gravitational effects such as the motions of visible matter, gravitational lensing, its influence on the universe's large-scale structure, and its effects in the cosmic microwave background. Dark matter is transparent to electromagnetic radiation and/or is so dense and small that it fails to absorb or emit enough radiation to be detectable with current imaging technology.

text: Dark matter is an unidentified type of

text: matter

text: comprising approximately 27% of the

text: mass and energy

text: in the

text: observable universe

text: that is not accounted for by

text: dark energy

text: baryonic matter

text: (ordinary matter), and

text: neutrinos

text: . The name refers to the fact that it does not emit or interact with

text: electromagnetic radiation

text: , such as light, and is thus invisible to the entire

text: electromagnetic spectrum

text: . Although dark matter has not been directly observed, its existence and properties are inferred from its gravitational effects such as the motions of visible matter,

text: gravitational lensing

text: , its influence on the universe's

text: large-scale structure

text: , and its effects in the

text: cosmic microwave background

text: . Dark matter is transparent to

text: electromagnetic radiation

text: and/or is so dense and small that it fails to absorb or emit enough radiation to be detectable with current imaging technology.

text: Scattering by particulates impairs visibility much more readily. Visibility is reduced by significant scattering from particles between an observer and a distant object. The particles scatter light from the sun and the rest of the sky through the line of sight of the observer, thereby decreasing the contrast between the object and the background sky. Particles that are the most effective at reducing visibility (per unit aerosol mass) have diameters in the range of 0.1-1.0 µm. The effect of air molecules on visibility is minor for short visual ranges but must be taken into account for ranges above 30 km.

text: Scattering by particulates impairs visibility much more readily. Visibility is reduced by significant scattering from particles between an observer and a distant object. The particles scatter light from the

text: sun

text: and the rest of the sky through the line of sight of the observer, thereby decreasing the contrast between the object and the background sky. Particles that are the most effective at reducing visibility (per unit

text: aerosol

text: mass) have diameters in the range of 0.1-1.0 µm. The effect of air molecules on visibility is minor for short visual ranges but must be taken into account for ranges above 30 km.

text: The silver-stained spots on the microarray are clearly visible. By using a transmission microarray scanner, the signals are transformed into digital values which are finally available as an image file.

text: A manual transmission, also known as a manual gearbox, stick shift, n-speed manual (where n is its number of forward gear ratios), standard, MT, or in colloquial U.S. English, a stick (for vehicles with hand-lever shifters), is a type of transmission used in motor vehicle applications. It uses a driver-operated clutch engaged and disengaged by a foot pedal (automobile) or hand lever (motorcycle), for regulating torque transfer from the engine to the transmission; and a gear selector operated by hand (automobile) or by foot (motorcycle).

text: A manual transmission, also known as a manual gearbox, stick shift, n-speed manual (where n is its number of forward gear ratios), standard, MT, or in colloquial

text: U.S. English

text: , a stick (for vehicles with hand-lever shifters), is a type of

text: transmission

text: used in

text: motor vehicle

text: applications. It uses a driver-operated

text: clutch

text: engaged and disengaged by a foot pedal (

text: automobile

text: ) or hand lever (

text: motorcycle

text: ), for regulating

text: torque

text: transfer from the

text: engine

text: to the transmission; and a

text: gear selector

text: operated by hand (automobile) or by foot (motorcycle).

text: In nature, a light source emits a ray of light that travels, eventually, to a surface that interrupts its progress.  One can think of this "ray" as a stream of photons travelling along the same path.  At this point, any combination of three things might happen with this light ray:  absorption, reflection, and refraction.  The surface may reflect all or part of the light ray, in one or more directions.  It might also absorb part of the light ray, resulting in a loss of intensity of the reflected and/or refracted light.  If the surface has any transparent or translucent properties, it refracts a portion of the light beam into itself in a different direction while absorbing some (or all) of the spectrum (and possibly altering the color).  Between absorption, reflection, and refraction, all of the incoming light must be accounted for, and no more.  A surface cannot, for instance, reflect 66% of an incoming light ray, and refract 50%, since the two would add up to be 116%. From here, the reflected and/or refracted rays may strike other surfaces, where their absorptive, refractive, and reflective properties are again calculated based on the incoming rays.  Some of these rays travel in such a way that they hit our eye, causing us to see the scene and so contribute to the final rendered image.  Attempting to simulate this real-world process of tracing light rays using a computer can be considered extremely wasteful, as only a minuscule fraction of the rays in a scene would actually reach the eye.

text: In nature, a light source emits a ray of light that travels, eventually, to a surface that interrupts its progress.  One can think of this "ray" as a stream of

text: photon

text: s travelling along the same path.  At this point, any combination of three things might happen with this light ray:

text: absorption

text: , reflection, and refraction.  The surface may reflect all or part of the light ray, in one or more directions.  It might also absorb part of the light ray, resulting in a loss of intensity of the reflected and/or refracted light.  If the surface has any

text: transparent

text: or

text: translucent

text: spectrum

text: (and possibly altering the color).  Between absorption, reflection, and refraction, all of the incoming light must be accounted for, and no more.  A surface cannot, for instance, reflect 66% of an incoming light ray, and refract 50%, since the two would add up to be 116%. From here, the reflected and/or refracted rays may strike other surfaces, where their absorptive, refractive, and reflective properties are again calculated based on the incoming rays.  Some of these rays travel in such a way that they hit our eye, causing us to see the scene and so contribute to the final rendered image.  Attempting to simulate this real-world process of tracing light rays using a computer can be considered extremely wasteful, as only a minuscule fraction of the rays in a scene would actually reach the eye.

text: As the new logos became part of the information systems at more and more main railway stations, an increasing number of cities and public transport operators came to accept and adopt the scheme. As far as the Stadtbahn terminology problem is concerned, however, the scheme serves only to add further confusion to the matter, since there is no nationwide logo for Stadtbahn services. The result appears to be a contraction in the use of the term Stadtbahn, especially in cities where it has been used in its wider 1980s 'light-rail system' meaning.

text: Sepia apama is a neritic demersal species. They are carnivorous, opportunistic and voracious predators who feed predominantly on crustaceans and fish. Using neurally controlled cells known as chromatophore organs (red to yellow), iridophores (iridescent: spans the entire visible spectrum from blue to near-IR) and leucophores (white), the cuttlefish can put on spectacular displays, changing colour and patterns in a fraction of a second. Located in three layers under the skin, leucophores make up the bottom layer, with chromatophores the outermost. By selective blocking, the three layers work together to produce polarised patterns. Unlike those in most animals, cuttlefish iridophores are physiologically active; they can change their reflectivity and the degree of polarization can also be controlled. Cuttlefish are colourblind, however the photoreceptors of cuttlefish eyes are arranged in a way which gives them the ability to see the linear polarization of light. While the mantis shrimp is the only known creature to have true polarization vision, it is believed that cephalopods may also. Because the optic lobes of cuttlefish are larger than any other region of the brain and their skin produces polarized reflective patterns, it has been postulated that they may communicate through this visual system.  By raising elaborate papillae on their skin, S. apama can change the shape and the texture of their skin to imitate rock, sand or seaweed.

text: Sepia apama is a

text: neritic

text: demersal

text: species. They are

text: carnivorous

text: , opportunistic and voracious

text: predators

text: who feed predominantly on

text: crustacean

text: s and fish. Using

text: neurally controlled

text: cells known as

text: chromatophore

text: organs (red to yellow),

text: iridophore

text: s (

text: iridescent

text: : spans the entire visible spectrum from blue to near-

text: IR

text: ) and

text: leucophore

text: s (white), the cuttlefish can put on spectacular displays, changing colour and patterns in a fraction of a second. Located in three layers under the skin, leucophores make up the bottom layer, with chromatophores the outermost. By selective blocking, the three layers work together to produce polarised patterns. Unlike those in most animals, cuttlefish iridophores are physiologically active; they can change their reflectivity and the degree of polarization can also be controlled. Cuttlefish are

text: colourblind

text: , however the photoreceptors of cuttlefish eyes are arranged in a way which gives them the ability to see the linear

text: polarization of light

text: . While the

text: mantis shrimp

text: is the only known creature to have true polarization vision, it is believed that

text: cephalopod

text: s may also. Because the optic lobes of cuttlefish are larger than any other region of the brain and their skin produces polarized reflective patterns, it has been postulated that they may communicate through this visual system.  By raising elaborate

text: papillae

text: on their skin, S. apama can change the shape and the texture of their skin to imitate rock, sand or seaweed.

text: Absorption is a disposition or personality trait in which a person becomes absorbed in their mental imagery, particularly fantasy. This trait thus correlates highly with a fantasy-prone personality. The original research on absorption was by American psychologist Auke Tellegen.  The construct of absorption was developed in order to relate individual differences in hypnotisability to broader aspects of personality. Absorption has a variable correlation with  hypnotisability (r =.13-89) perhaps because in addition to broad personality dispositions, situational factors play an important role in performance on tests of hypnotic susceptibility. Absorption is one of the traits assessed in the Multidimensional Personality Questionnaire.

text: Absorption is a disposition or

text: personality trait

text: in which a person becomes absorbed in their mental imagery, particularly fantasy. This trait thus correlates highly with a

text: fantasy-prone personality

text: . The original research on absorption was by American psychologist

text: Auke Tellegen

text: .  The construct of absorption was developed in order to relate individual differences in

text: hypnotisability

text: to broader aspects of personality. Absorption has a variable correlation with  hypnotisability (r =.13-89) perhaps because in addition to broad personality dispositions, situational factors play an important role in performance on tests of hypnotic susceptibility. Absorption is one of the traits assessed in the

text: Multidimensional Personality Questionnaire

text: The color of a cloud, as seen from the Earth, tells much about what is going on inside the cloud.  Dense deep tropospheric clouds exhibit a high reflectance (70% to 95%) throughout the visible spectrum. Tiny particles of water are densely packed and sunlight cannot penetrate far into the cloud before it is reflected out, giving a cloud its characteristic white color, especially when viewed from the top. Cloud droplets tend to scatter light efficiently, so that the intensity of the solar radiation decreases with depth into the gases.  As a result, the cloud base can vary from a very light to very dark grey depending on the cloud's thickness and how much light is being reflected or transmitted back to the observer.  Thin clouds may look white or appear to have acquired the color of their environment or background.  High tropospheric and non-tropospheric clouds appear mostly white if composed entirely of ice crystals and/or supercooled water droplets.

text: The color of a cloud, as seen from the Earth, tells much about what is going on inside the cloud.  Dense deep tropospheric clouds exhibit a high reflectance (70% to 95%) throughout the

text: visible spectrum

text: . Tiny particles of water are densely packed and sunlight cannot penetrate far into the cloud before it is reflected out, giving a cloud its characteristic white color, especially when viewed from the top. Cloud droplets tend to scatter light efficiently, so that the intensity of the

text: solar radiation

text: decreases with depth into the gases.  As a result, the

text: cloud base

text: can vary from a very light to very dark grey depending on the cloud's thickness and how much

text: light

text: is being reflected or transmitted back to the observer.  Thin clouds may look white or appear to have acquired the color of their

text: environment

text: or background.  High tropospheric and non-tropospheric clouds appear mostly white if composed entirely of ice crystals and/or supercooled water droplets.

text: Post-Newtonian formalism is a calculational tool that expresses Einstein's (nonlinear) equations of gravity in terms of the lowest-order deviations from Newton's law of universal gravitation. This allows approximations to Einstein's equations to be made in the case of weak fields. Higher order terms can be added to increase accuracy, but for strong fields sometimes it is preferable to solve the complete equations numerically. Some of these post-Newtonian approximations are expansions in a small parameter, which is the ratio of the velocity of the matter forming the gravitational field to the speed of light, which in this case is better called the speed of gravity. In the limit, when the fundamental speed of gravity becomes infinite, the post-Newtonian expansion reduces to Newton's law of gravity.

text: Post-Newtonian formalism is a calculational tool that expresses

text: Einstein's (nonlinear) equations of gravity

text: in terms of the lowest-order deviations from

text: Newton's law of universal gravitation

text: . This allows approximations to Einstein's equations to be made in the case of weak fields. Higher order terms can be added to increase accuracy, but for strong fields sometimes it is preferable to solve the complete equations numerically. Some of these post-Newtonian approximations are expansions in a small parameter, which is the ratio of the velocity of the matter forming the gravitational field to the speed of light, which in this case is better called the

text: speed of gravity

text: . In the limit, when the fundamental speed of gravity becomes infinite, the

text: post-Newtonian expansion

text: reduces to Newton's law of gravity.

text: The goal of any absorption spectroscopy (FTIR, ultraviolet-visible ("UV-Vis") spectroscopy, etc.) is to measure how well a sample absorbs light at each wavelength. The most straightforward way to do this, the "dispersive spectroscopy" technique, is to shine a monochromatic light beam at a sample, measure how much of the light is absorbed, and repeat for each different wavelength. (This is how some UV-Vis spectrometers work, for example.)

text: The goal of any

text: absorption spectroscopy

text: (FTIR,

text: ultraviolet-visible ("UV-Vis") spectroscopy

text: , etc.) is to measure how well a sample absorbs light at each wavelength. The most straightforward way to do this, the "dispersive spectroscopy" technique, is to shine a

text: monochromatic

text: light beam at a sample, measure how much of the light is absorbed, and repeat for each different wavelength. (This is how some

text: UV-Vis spectrometers

text: work, for example.)

text: Reflection in computer graphics is used to emulate reflective objects like mirrors and shiny surfaces.

text: Reflection in

text: computer graphics

text: is used to emulate

text: reflective

text: objects like

text: mirror

text: s and shiny surfaces.

text: The windshield glass itself blocks most of the UV light and some of the infrared radiation. But it can't protect from the visible light that mostly penetrates through it and gets absorbed by the objects inside the car. The visible light that passes into the interior through the windshield is converted into the infrared light which, in its turn, is blocked by the glass and gets trapped inside, heating up the interior. Windshield sun shades have a reflective surface to bounce the light back, reducing the interior temperature.

text: The windshield glass itself blocks most of the UV light and some of the infrared

text: radiation

text: . But it can't protect from the visible light that mostly penetrates through it and gets absorbed by the objects inside the car. The visible light that passes into the interior through the windshield is converted into the infrared light which, in its turn, is blocked by the glass and gets trapped inside, heating up the interior. Windshield sun shades have a reflective surface to bounce the light back, reducing the interior temperature.

text: Photoconductivity is an optical and electrical phenomenon in which a material becomes more electrically conductive due to the absorption of electromagnetic radiation such as visible light, ultraviolet light, infrared light, or gamma radiation.

text: Photoconductivity is an

text: optical

text: and

text: electrical phenomenon

text: in which a material becomes more

text: electrically conductive

text: due to the absorption of

text: electromagnetic radiation

text: such as

text: visible light

text: ultraviolet

text: light,

text: infrared

text: light, or

text: gamma radiation

text: These results can be classified as a metric f(R) gravity theory, more properly an f(R,T) theory, derived from an action principle. This approach to solve the dark matter problem takes into account the Tully–Fisher relation as an empirical law that applies always at scales larger than the Milgrom radius.

text: These results can be classified as a metric

text: f(R) gravity

text: theory, more properly an f(R,T) theory, derived from an

text: action principle

text: . This approach to solve the dark matter problem takes into account the

text: Tully–Fisher relation

text: as an empirical law that applies always at scales larger than the

text: Milgrom radius

text: An ultramicroscope is a microscope with a system of illumination that allows viewing of tiny particles. When the diameter of a particle is below or near the wavelength of visible light (around 500 nanometers), the particle cannot be seen in a light microscope with the usual method of illumination. The ultramicroscope system is based on light scattering, not light reflection.

text: An ultramicroscope is a

text: microscope

text: with a system of illumination that allows viewing of tiny particles. When the diameter of a particle is below or near the

text: wavelength

text: of

text: visible light

text: (around 500

text: nanometer

text: s), the particle cannot be seen in a

text: light microscope

text: with the usual method of illumination. The ultramicroscope system is based on

text: light scattering

text: , not

text: light reflection

text: A black light may also be formed by simply using Wood's glass as the envelope for a common incandescent bulb. This was the method that was used to create the very first black light sources. Although incandescent black light bulbs are a cheaper alternative to fluorescent tubes, they are exceptionally inefficient at producing UV light since most of the light emitted by the filament is visible light which must be blocked. Due to its black body spectrum, an incandescent light radiates less than 0.1% of its energy as UV light. Incandescent UV bulbs, due to the necessary absorption of the visible light, become very hot during use. This heat is, in fact, encouraged in such bulbs, since a hotter filament increases the proportion of UVA in the black-body radiation emitted. This high running-temperature drastically reduces the life of the lamp, however, from a typical 1000 hours to around 100 hours.

text: A black light may also be formed by simply using

text: Wood's glass

text: as the envelope for a common

text: incandescent bulb

text: . This was the method that was used to create the very first black light sources. Although incandescent black light bulbs are a cheaper alternative to fluorescent tubes, they are exceptionally inefficient at producing UV light since most of the light emitted by the filament is visible light which must be blocked. Due to its

text: black body

text: spectrum, an incandescent light radiates less than 0.1% of its energy as UV light. Incandescent UV bulbs, due to the necessary absorption of the visible light, become very hot during use. This heat is, in fact, encouraged in such bulbs, since a hotter filament increases the proportion of UVA in the black-body radiation emitted. This high running-temperature drastically reduces the life of the lamp, however, from a typical 1000 hours to around 100 hours.

text: The visible surface of the Sun, the photosphere, is the layer below which the Sun becomes opaque to visible light. Above the photosphere visible sunlight is free to propagate into space, and its energy escapes the Sun entirely. The change in opacity is due to the decreasing amount of H ions, which absorb visible light easily. Conversely, the visible light we see is produced as electrons react with hydrogen atoms to produce H ions.The photosphere is tens to hundreds of kilometers thick, and is slightly less opaque than air on Earth. Because the upper part of the photosphere is cooler than the lower part, an image of the Sun appears brighter in the center than on the edge or limb of the solar disk, in a phenomenon known as limb darkening. The spectrum of sunlight has approximately the spectrum of a black-body radiating at about 6,000 K, interspersed with atomic absorption lines from the tenuous layers above the photosphere. The photosphere has a particle density of ~10 m (about 0.37% of the particle number per volume of Earth's atmosphere at sea level). The photosphere is not fully ionized—the extent of ionization is about 3%, leaving almost all of the hydrogen in atomic form.

text: The visible surface of the Sun, the photosphere, is the layer below which the Sun becomes

text: opaque

text: to visible light. Above the photosphere visible sunlight is free to propagate into space, and its energy escapes the Sun entirely. The change in opacity is due to the decreasing amount of

text: H ions

text: , which absorb visible light easily. Conversely, the visible light we see is produced as electrons react with

text: hydrogen

text: atoms to produce H ions.The photosphere is tens to hundreds of kilometers thick, and is slightly less opaque than air on Earth. Because the upper part of the photosphere is cooler than the lower part, an image of the Sun appears brighter in the center than on the edge or limb of the solar disk, in a phenomenon known as

text: limb darkening

text: . The spectrum of sunlight has approximately the spectrum of a

text: black-body

text: radiating at about 6,000

text: K

text: , interspersed with atomic

text: absorption line

text: s from the tenuous layers above the photosphere. The photosphere has a particle density of ~10 m (about 0.37% of the particle number per volume of

text: Earth's atmosphere

text: at sea level). The photosphere is not fully ionized—the extent of ionization is about 3%, leaving almost all of the hydrogen in atomic form.

text: Fluorescent lighting converts ultraviolet light to visible light. In order to produce ultraviolet light, electrons flow through the fluorescent lamp and collide with mercury atoms. The collision with mercury causes photons of UV light to be released; the UV light is then converted to visible light as it passes through the phosphor coating in the glass tube.

text: Fluorescent lighting

text: converts ultraviolet light to visible light. In order to produce ultraviolet light, electrons flow through the fluorescent lamp and collide with mercury atoms. The collision with mercury causes photons of UV light to be released; the UV light is then converted to visible light as it passes through the phosphor coating in the glass tube.

text: The degenerate matter that makes up the bulk of a white dwarf has a very low opacity, because any absorption of a photon requires that an electron must transition to a higher empty state, which may not be possible as the energy of the photon may not be a match for the possible quantum states available to that electron, hence radiative heat transfer within a white dwarf is low; it does, however, have a high thermal conductivity. As a result, the interior of the white dwarf maintains a uniform temperature, approximately 10 K. An outer shell of non-degenerate matter cools from approximately 10 K to 10 K. This matter radiates roughly as a black body. A white dwarf remains visible for a long time, as its tenuous outer atmosphere of normal matter begins to radiate at about 10 K, upon formation, while its greater interior mass is at 10 K but cannot radiate through its normal matter shell.

text: The degenerate matter that makes up the bulk of a white dwarf has a very low

text: opacity

text: , because any absorption of a photon requires that an electron must transition to a higher empty state, which may not be possible as the energy of the photon may not be a match for the possible quantum states available to that electron, hence radiative heat transfer within a white dwarf is low; it does, however, have a high

text: thermal conductivity

text: . As a result, the interior of the white dwarf maintains a uniform temperature, approximately 10 K. An outer shell of non-degenerate matter cools from approximately 10 K to 10 K. This matter radiates roughly as a

text: black body

text: . A white dwarf remains visible for a long time, as its tenuous outer atmosphere of normal matter begins to radiate at about 10 K, upon formation, while its greater interior mass is at 10 K but cannot radiate through its normal matter shell.

text: An automatic transmission is an automobile gearbox that changes gear ratios automatically as the vehicle moves, freeing the driver from having to shift gears manually. Modern automatic transmissions trace their origins to an early "horseless carriage" gearbox that was developed in 1904 by the Sturtevant brothers of Boston, Massachusetts.

text: Robert Bailey, along with James C. Fletcher, received a patent () in 1973 for an "electromagnetic wave energy converter". The patented device was similar to modern day optical rectennas. The patent discusses the use of a diode "type described by Javin (sic) in the IEEE Spectrum, October, 1971, page 91", to whit, a 100 nm-diameter metal cat's whisker to a metal surface covered with a thin oxide layer. Javan was reported as having rectified 58 THz infrared light. In 1974, T. Gustafson and coauthors demonstrated that these types of devices could rectify even visible light to DC current Alvin M. Marks received a patent in 1984 for a device explicitly stating the use of sub-micron antennas for the direct conversion of light power to electrical power. Marks’s device showed substantial improvements in efficiency over Bailey’s device.In 1996, Guang H. Lin reported resonant light absorption by a fabricated nanostructure and rectification of light with frequencies in the visible range. In 2002, ITN Energy Systems, Inc. published a report on their work on optical antennas coupled with high frequency diodes. ITN set out to build an optical rectenna array with single digit efficiency. Although they were unsuccessful, the issues associated with building a high efficiency optical rectenna were better understood.

text: Robert Bailey, along with James C. Fletcher, received a patent () in 1973 for an "electromagnetic wave energy converter". The patented device was similar to modern day optical rectennas. The patent discusses the use of a diode "type described by

text: Javin (sic)

text: in the IEEE Spectrum, October, 1971, page 91", to whit, a 100 nm-diameter metal

text: cat's whisker

text: to a metal surface covered with a thin oxide layer. Javan was reported as having rectified 58 THz infrared light. In 1974, T. Gustafson and coauthors demonstrated that these types of devices could rectify even visible light to DC current Alvin M. Marks received a patent in 1984 for a device explicitly stating the use of sub-micron antennas for the direct conversion of light power to electrical power. Marks’s device showed substantial improvements in efficiency over Bailey’s device.In 1996, Guang H. Lin reported resonant light absorption by a fabricated nanostructure and rectification of light with frequencies in the visible range. In 2002, ITN Energy Systems, Inc. published a report on their work on optical antennas coupled with high frequency

text: diode

text: s. ITN set out to build an optical rectenna array with single digit efficiency. Although they were unsuccessful, the issues associated with building a high efficiency optical rectenna were better understood.

text: Granulocytes are distinguished from agranulocytes by their nucleus shape (lobed versus round, that is, polymorphonuclear versus mononuclear) and by their cytoplasm granules (present or absent, or more precisely, visible on light microscopy or not thus visible). The other dichotomy is by lineage: Myeloid cells (neutrophils, monocytes, eosinophils and basophils) are distinguished from lymphoid cells (lymphocytes) by hematopoietic lineage (cellular differentiation lineage). Lymphocytes can be further classified as T cells, B cells, and natural killer cells.

text: Granulocytes are distinguished from agranulocytes by their nucleus shape (lobed versus round, that is, polymorphonuclear versus mononuclear) and by their cytoplasm

text: granules

text: (present or absent, or more precisely, visible on light microscopy or not thus visible). The other dichotomy is by lineage: Myeloid cells (

text: neutrophils

text: monocytes

text: eosinophils

text: and

text: basophils

text: ) are distinguished from lymphoid cells (

text: lymphocytes

text: ) by

text: hematopoietic

text: lineage (

text: cellular differentiation

text: lineage).

text: Lymphocytes

text: can be further classified as T cells, B cells, and natural killer cells.

text: Generally speaking, the higher an object's temperature, the more infrared radiation is emitted as black-body radiation. A special camera can detect this radiation in a way similar to the way an ordinary camera detects visible light.  It works even in total darkness because ambient light level does not matter. This makes it useful for rescue operations in smoke-filled buildings and underground.

text: Generally speaking, the higher an object's temperature, the more infrared radiation is emitted as

text: black-body radiation

text: . A special

text: camera

text: can detect this radiation in a way similar to the way an ordinary camera detects visible light.  It works even in total darkness because ambient light level does not matter. This makes it useful for rescue operations in smoke-filled buildings and underground.

text: The primary engineering feature of the line was the tunnel through Richmond Hill in Leeds. It was  long, with its western entrance at  from the Leeds terminus. The tunnel's cross section was that of a horseshoe arch,  at its widest, and  high from the level of the rails. The construction of the tunnel required the sinking of three shafts, subsequently retained for ventilation. Excavation of the tunnel yielded mostly shale and coal, with the remaining third being stone which was used as foundations for other parts of the line. The arch was lined with two courses of brickwork, lengthways to a thickness of 20 inches. In some places three courses were used, depending on the strength of the surrounding ground. Volcanic matter was used in the mortar, to obtain a quick-setting and strong cement. The entrances of the tunnel were faced with stone. There were once reflectors at the base of the shafts, designed to reflect light onto the whitewashed walls of the tunnel. The shafts were found to be useful for ventilation, but the experiment with illuminating the interior with reflect light was of limited utility to passengers; lamps were provided to light the carriages. Despite the efforts, an early passenger reported that on entering the tunnel:

text: The primary engineering feature of the line was the tunnel through

text: Richmond Hill

text: in Leeds. It was  long, with its western entrance at  from the Leeds terminus. The tunnel's cross section was that of a

text: horseshoe arch

text: ,  at its widest, and  high from the level of the rails. The construction of the tunnel required the sinking of three shafts, subsequently retained for ventilation. Excavation of the tunnel yielded mostly shale and coal, with the remaining third being stone which was used as foundations for other parts of the line. The arch was lined with two courses of brickwork, lengthways to a thickness of 20 inches. In some places three courses were used, depending on the strength of the surrounding ground. Volcanic matter was used in the mortar, to obtain a quick-setting and strong cement. The entrances of the tunnel were faced with stone. There were once reflectors at the base of the shafts, designed to reflect light onto the whitewashed walls of the tunnel. The shafts were found to be useful for ventilation, but the experiment with illuminating the interior with reflect light was of limited utility to passengers; lamps were provided to light the carriages. Despite the efforts, an early passenger reported that on entering the tunnel:

text: Another form of atmospheric diffraction or bending of light occurs when light moves through fine layers of particulate dust trapped primarily in the middle layers of the troposphere. This effect differs from water based atmospheric diffraction because the dust material is opaque whereas water allows light to pass through it. This has the effect of tinting the light the color of the dust particles. This tinting can vary from red to yellow depending on geographical location. the other primary difference is that dust based diffraction acts as a magnifier instead of creating a distinct halo. This occurs because the opaque matter does not share the lensing properties of water. The effect is to make an object visibly larger while being more indistinct as the dust distorts the image. This effect varies largely based on the amount and type of dust in the atmosphere.

text: Another form of atmospheric

text: diffraction

text: or bending of light occurs when light moves through fine layers of

text: particulate

text: dust trapped primarily in the middle layers of the

text: troposphere

text: . This effect differs from water based atmospheric diffraction because the dust material is

text: opaque

text: whereas water allows light to pass through it. This has the effect of

text: tint

text: ing the light the color of the dust particles. This tinting can vary from red to yellow depending on geographical location. the other primary difference is that dust based diffraction acts as a

text: magnifier

text: instead of creating a distinct

text: halo

text: . This occurs because the opaque matter does not share the lensing properties of water. The effect is to make an object visibly larger while being more indistinct as the dust distorts the image. This effect varies largely based on the amount and type of dust in the atmosphere.

text: Light, or visible light, is a very narrow range of electromagnetic radiation of a wavelength that is visible to the human eye (about 400–700 nm), or up to 380–750 nm. More broadly, physicists refer to light as electromagnetic radiation of all wavelengths, whether visible or not.

text: Sports cars are also often equipped with manual transmissions because they offer more direct driver involvement and better performance, though this is changing as many automakers move to faster dual-clutch transmissions, which are generally shifted with paddles located behind the steering wheel. For example, the 991 Porsche 911 GT3 uses Porsche's PDK. Off-road vehicles and trucks often feature manual transmissions because they allow direct gear selection and are often more rugged than their automatic counterparts.

text: Sports cars are also often equipped with manual transmissions because they offer more direct driver involvement and better performance, though this is changing as many automakers move to faster dual-clutch transmissions, which are generally shifted with paddles located behind the steering wheel. For example, the 991

text: Porsche 911 GT3

text: uses Porsche's PDK. Off-road vehicles and trucks often feature manual transmissions because they allow direct gear selection and are often more rugged than their automatic counterparts.

text: Unlike visible light, X-rays do not reflect or refract easily, and they are invisible to the human eye. Therefore, the basic process of an X-ray microscope is to expose film or use a charge-coupled device (CCD) detector to detect X-rays that pass through the specimen. It is a contrast imaging technology using the difference in absorption of soft X-rays in the water window region (wavelengths: 2.34-4.4 nm, energies: 280-530 eV) by the carbon atom (main element composing the living cell) and the oxygen atom (main element for water).

text: Unlike visible

text: light

text: , X-rays do not reflect or refract easily, and they are invisible to the human eye. Therefore, the basic process of an X-ray microscope is to expose film or use a

text: charge-coupled device

text: (CCD) detector to detect X-rays that pass through the specimen. It is a contrast imaging technology using the difference in absorption of soft X-rays in the

text: water window

text: region (wavelengths: 2.34-4.4 nm, energies: 280-530 eV) by the carbon atom (main element composing the living cell) and the oxygen atom (main element for water).

text: Most nebulae can be described as diffuse nebulae, which means that they are extended and contain no well-defined boundaries.  Diffuse nebulae can be divided into emission nebula, reflection nebulae and "dark nebulae." In visible light nebulae may be divided into emission nebulae that emit spectral line radiation from excited or ionized gas (mostly ionized hydrogen);  they are often called HII regions (the term "HII"  refers to ionized hydrogen). Reflection nebulae are visible primarily due to the light they reflect. Reflection nebulae themselves do not emit significant amounts of visible light, but are near stars and reflect light from them. Similar nebulae not illuminated by stars do not exhibit visible radiation, but may be detected as opaque clouds blocking light from luminous objects behind them; they are called "dark nebulae".

text: Most nebulae can be described as diffuse nebulae, which means that they are extended and contain no well-defined boundaries.  Diffuse nebulae can be divided into

text: emission nebula

text: reflection nebula

text: e and "dark nebulae." In visible light nebulae may be divided into emission nebulae that emit

text: spectral line

text: radiation from excited or

text: ion

text: ized gas (mostly ionized

text: hydrogen

text: );  they are often called

text: HII regions

text: (the term "HII"  refers to ionized hydrogen).

text: Reflection nebula

text: e are visible primarily due to the light they reflect. Reflection nebulae themselves do not emit significant amounts of visible light, but are near stars and reflect light from them. Similar nebulae not illuminated by stars do not exhibit visible radiation, but may be detected as opaque clouds blocking light from luminous objects behind them; they are called "dark nebulae".

text: The Platform marked a conservative counter-revolution against a non-conformist tide which had begun with the Halfway Covenant and would later culminate in the Great Awakening in the 1740s. The Great Awakening bitterly divided Congregationalists between the "New Lights" or "Arminians" who welcomed the revivals, and the "Old Lights" or "Calvinists" who used governmental authority to suppress revivals. Theologically, the Arminians believed that every person could be saved by experiencing a religious conversion and one of the revivals; the Calvinists held that everyone's fate was a matter of predestination, and revivals were a false religion.

text: The Platform marked a conservative counter-revolution against a non-conformist tide which had begun with the

text: Halfway Covenant

text: and would later culminate in the

text: Great Awakening

text: in the 1740s. The Great Awakening bitterly divided Congregationalists between the "New Lights" or "Arminians" who welcomed the revivals, and the "Old Lights" or "Calvinists" who used governmental authority to suppress revivals. Theologically, the Arminians believed that every person could be saved by experiencing a religious conversion and one of the revivals; the Calvinists held that everyone's fate was a matter of predestination, and revivals were a false religion.

text: Precise measurements of the absorbance at many wavelengths allow the identification of a substance via absorption spectroscopy, where a sample is illuminated from one side, and the intensity of the light that exits from the sample in every direction is measured. A few examples of absorption are ultraviolet–visible spectroscopy, infrared spectroscopy, and X-ray absorption spectroscopy.

text: Precise measurements of the absorbance at many wavelengths allow the identification of a substance via

text: absorption spectroscopy

text: , where a sample is illuminated from one side, and the intensity of the light that exits from the sample in every direction is measured. A few examples of absorption are

text: ultraviolet–visible spectroscopy

text: infrared spectroscopy

text: , and

text: X-ray absorption spectroscopy

text: Absorption is a primary focus in drug development and medicinal chemistry, since the drug must be absorbed before any medicinal effects can take place.  Moreover, the drug's pharmacokinetic profile can be easily and significantly changed by adjusting factors that affect absorption.

text: Absorption is a primary focus in

text: drug development

text: and

text: medicinal chemistry

text: , since the drug must be absorbed before any medicinal effects can take place.  Moreover, the drug's pharmacokinetic profile can be easily and significantly changed by adjusting factors that affect absorption.

text: Thus, because the energy density is negative, one needs exotic matter to travel faster than the speed of light. The existence of exotic matter is not theoretically ruled out; however, generating and sustaining enough exotic matter to perform feats such as faster-than-light travel (and also to keep open the 'throat' of a wormhole) is thought to be impractical. Low has argued that within the context of general relativity, it is impossible to construct a warp drive in the absence of exotic matter.

text: Thus, because the energy density is negative, one needs

text: exotic matter

text: to travel faster than the speed of light. The existence of exotic matter is not theoretically ruled out; however, generating and sustaining enough exotic matter to perform feats such as faster-than-light travel (and also to keep open the 'throat' of a

text: wormhole

text: ) is thought to be impractical. Low has argued that within the context of general relativity, it is impossible to construct a warp drive in the absence of exotic matter.

text: Within a few seconds, a substantial fraction of the matter in the white dwarf undergoes nuclear fusion, releasing enough energy (1–) to unbind the star in a supernova explosion. An outwardly expanding shock wave is generated, with matter reaching velocities on the order of 5,000–20,000 km/s, or roughly 3% of the speed of light. There is also a significant increase in luminosity, reaching an absolute magnitude of −19.3 (or 5 billion times brighter than the Sun), with little variation.

text: Within a few seconds, a substantial fraction of the matter in the white dwarf undergoes nuclear fusion, releasing enough energy (1–) to unbind the star in a supernova explosion. An outwardly expanding

text: shock wave

text: is generated, with matter reaching velocities on the order of 5,000–20,000

text: km/s

text: , or roughly 3% of the speed of light. There is also a significant increase in luminosity, reaching an

text: absolute magnitude

text: of −19.3 (or 5 billion times brighter than the Sun), with little variation.

text: The Church Times was founded on 7 February 1863 by George Josiah Palmer, a printer. It fought for the Anglo-Catholic cause in the Church of England at a time when priests were being harried and imprisoned over such matters as lighting candles on altars and wearing vestments, which brought them into conflict with the Public Worship Regulation Act, intended to “put down” Ritualism. The paper defended the spiritual independence of the Church of England in spite of the Church’s Established status. Many of the ceremonial and doctrinal matters that the paper championed are now accepted as part of mainstream Anglicanism.

text: The Church Times was founded on 7 February 1863 by George Josiah Palmer, a printer. It fought for the

text: Anglo-Catholic cause

text: in the Church of England at a time when priests were being harried and imprisoned over such matters as lighting candles on altars and wearing vestments, which brought them into conflict with the Public Worship Regulation Act, intended to “put down” Ritualism. The paper defended the spiritual independence of the Church of England in spite of the Church’s Established status. Many of the ceremonial and doctrinal matters that the paper championed are now accepted as part of mainstream Anglicanism.

text: The main disadvantage of absorption spectrometry (AS) as well as laser absorption spectrometry (LAS) in general is that it relies on a measurement of a small change of a signal on top of a large background. Any noise introduced by the light source or the optical system will deteriorate the detectability of the technique. The sensitivity of direct absorption techniques is therefore often limited to an absorbance of ~10, far away from the shot noise level, which for single pass direct AS (DAS) is in the 10 – 10 range. Since this is insufficient for many types of applications, AS is seldom used in its simplest mode of operation.

text: The main disadvantage of

text: absorption spectrometry

text: (AS) as well as

text: laser absorption spectrometry

text: (LAS) in general is that it relies on a measurement of a small change of a signal on top of a large background. Any noise introduced by the light source or the optical system will deteriorate the detectability of the technique. The sensitivity of direct absorption techniques is therefore often limited to an absorbance of ~10, far away from the shot noise level, which for single pass direct AS (DAS) is in the 10 – 10 range. Since this is insufficient for many types of applications, AS is seldom used in its simplest mode of operation.

text: Moreover, such methods are completely blind to molecules that have no dipole. For example, by far the most common molecule in the universe is H (hydrogen gas), but it does not have a dipole moment, so it is invisible to radio telescopes. Moreover, such methods cannot detect species that are not in the gas-phase. Since dense molecular clouds are very cold (), most molecules in them (other than hydrogen) are frozen, i.e. solid. Instead, hydrogen and these other molecules are detected using other wavelengths of light. Hydrogen is easily detected in the ultraviolet (UV) and visible ranges from its absorption and emission of light (the hydrogen line). Moreover, most organic compounds absorb and emit light in the infrared (IR) so, for example, the  detection of methane in the atmosphere of Mars was achieved using an IR ground-based telescope, NASA's 3-meter Infrared Telescope Facility atop Mauna Kea, Hawaii. NASA's researchers use airborne IR telescope SOFIA and space telescope Spitzer for their observations, researches and scientific operations.  Somewhat related to the recent detection of methane in the atmosphere of Mars. Christopher Oze, of the University of Canterbury in New Zealand and his colleagues reported, in June 2012, that measuring the ratio of hydrogen and methane levels on Mars may help determine the likelihood of life on Mars. According to the scientists, "...low H/CH ratios (less than approximately 40) indicate that life is likely present and active."  Other scientists have recently reported methods of detecting hydrogen and methane in extraterrestrial atmospheres.

text: Moreover, such methods are completely blind to molecules that have no

text: dipole

text: . For example, by far the most common molecule in the universe is H (

text: hydrogen

text: gas), but it does not have a dipole moment, so it is invisible to radio telescopes. Moreover, such methods cannot detect species that are not in the gas-phase. Since dense molecular clouds are very cold (), most molecules in them (other than hydrogen) are frozen, i.e. solid. Instead, hydrogen and these other molecules are detected using other wavelengths of light. Hydrogen is easily detected in the ultraviolet (UV) and visible ranges from its absorption and emission of light (the

text: hydrogen line

text: ). Moreover, most organic compounds absorb and emit light in the infrared (IR) so, for example, the  detection of

text: methane

text: in the atmosphere of Mars was achieved using an IR ground-based telescope, NASA's 3-meter

text: Infrared Telescope Facility

text: atop Mauna Kea, Hawaii. NASA's researchers use airborne IR telescope

entity_name: Stratospheric Observatory for Infrared Astronomy

text: SOFIA

text: and space telescope

text: Spitzer

text: for their observations, researches and scientific operations.  Somewhat related to the recent detection of

text: methane

text: in the

text: atmosphere of Mars

text: . Christopher Oze, of the

text: University of Canterbury

text: in

text: New Zealand

text: and his colleagues reported, in June 2012, that measuring the ratio of

text: hydrogen

text: and

text: methane

text: levels on Mars may help determine the likelihood of

text: life on Mars

text: . According to the scientists, "...low H/CH ratios (less than approximately 40) indicate that life is likely present and active."  Other scientists have recently reported methods of detecting hydrogen and methane in

text: extraterrestrial atmospheres

text: The distinction between B and C is demonstrated in the following example: In the evening, one can go out and see at the same moment the sun setting, the moon and a few stars; this is our reality or B. In the scientific domain C, however, the analysis of B reveals that the stars are thousands of light years away, the sun is eight light minutes away, and the moon is about a light second away. Since one cannot logically consider these subjects to be both "at the same moment" and "away in time", an exclusive choice has to be made that defines these two separate domains, B and C. Our reality or domain B is created by the complex, but consistent transformation of A by our biological and mental makeup. Therefore, domain B, or our reality, is internally logical. The scientific knowledge, or domain C, is created by the application of a consistent methodology of analysis of our reality, B. Therefore, the scientific domain is internally logical. Domains B and C each have their own internal logic, derived from a consistent approach respecting both processes and subject matter. Using the questions or processes of one domain on the subject matter of another domain will logically produce puzzles, paradoxes, and inconsistencies. The Ship of Theseus problem is an example of such an inconsistency created by the use of the question of identity proper to the ontology of domain A, applied to the subject matter of domain B, our reality. The question about the identity of the Ship of Theseus is simply not receivable and comes from the poor practice of not respecting the proper correspondence of the question domain to the subject matter domain. The problem of identity is an ontological problem, and should therefore be applied to the (metaphysical) subject matter of domain A, the real universe.

text: The distinction between B and C is demonstrated in the following example: In the evening, one can go out and see at the same moment the sun setting, the moon and a few stars; this is our reality or B. In the scientific domain C, however, the analysis of B reveals that the stars are thousands of light years away, the sun is eight light minutes away, and the moon is about a light second away. Since one cannot logically consider these subjects to be both "at the same moment" and "away in time", an exclusive choice has to be made that defines these two separate domains, B and C. Our reality or domain B is created by the complex, but consistent transformation of A by our biological and mental makeup. Therefore, domain B, or our reality, is internally logical. The scientific knowledge, or domain C, is created by the application of a consistent

text: methodology

text: of analysis of our reality, B. Therefore, the scientific domain is internally logical. Domains B and C each have their own internal logic, derived from a consistent approach respecting both processes and subject matter. Using the questions or processes of one domain on the subject matter of another domain will logically produce puzzles,

text: paradox

text: es, and inconsistencies. The Ship of Theseus problem is an example of such an inconsistency created by the use of the question of identity proper to the ontology of domain A, applied to the subject matter of domain B, our reality. The question about the identity of the Ship of Theseus is simply not receivable and comes from the poor practice of not respecting the proper correspondence of the question domain to the subject matter domain. The problem of identity is an ontological problem, and should therefore be applied to the (metaphysical) subject matter of domain A, the real universe.

text: Transparent conductive polymers are used as electrodes on light emitting diodes and photovoltaic devices. They have conductivity below that of transparent conducting oxides but have low absorption of the visible spectrum allowing them to act as a transparent conductor on these devices. However, because transparent conductive polymers do absorb some of the visible spectrum and significant amounts of the mid to near IR, they lower the efficiency of photovoltaic devices.

text: In surface waters, phototransformation can substantially contribute to degradation. In “direct” phototransformation, photons are absorbed by the contaminant, while in “indirect” phototransformation, reactive species are formed through photon absorption by other substances. Pesticide electronic absorption spectra typically show little overlap with sunlight, such that only a few (e.g., trifluralin) are affected by direct phototransformation. Various photochemically active light absorbers are present in surface waters, enhancing indirect phototransformation. The most prominent is dissolved organic matter (DOM), which is the precursor of excited triplet states, molecular oxygen, superoxide radical anions, and other radicals. Nitrate and nitrite ions produce hydroxyl radicals under irradiation. Indirect phototransformation is thus the result of parallel reactions with all available reactive species. The transformation rate depends on the concentrations of all relevant reactive species, together with their corresponding second-order rate constants for a given pesticide. These constants are known for hydroxyl radical and molecular oxygen. In the absence of such rate constants, quantitative structure–activity relationships(QSARs) may allow their estimation for a specific pesticide from its chemical structure.

text: In surface waters, phototransformation can substantially contribute to degradation. In “direct” phototransformation, photons are absorbed by the contaminant, while in “indirect” phototransformation, reactive species are formed through photon absorption by other substances. Pesticide electronic absorption spectra typically show little overlap with

text: sunlight

text: , such that only a few (e.g.,

text: trifluralin

text: ) are affected by direct phototransformation. Various photochemically active light absorbers are present in surface waters, enhancing indirect phototransformation. The most prominent is

text: dissolved organic matter

text: (DOM), which is the precursor of excited triplet states, molecular oxygen, superoxide radical

text: anion

text: s, and other radicals.

text: Nitrate

text: and

text: nitrite

text: ions produce

text: hydroxyl

text: radicals under irradiation. Indirect phototransformation is thus the result of parallel reactions with all available reactive species. The transformation rate depends on the concentrations of all relevant reactive species, together with their corresponding second-order rate constants for a given pesticide. These constants are known for hydroxyl radical and molecular oxygen. In the absence of such rate constants,

text: quantitative structure–activity relationship

text: s(QSARs) may allow their estimation for a specific pesticide from its chemical structure.

text: The angular momentum of light is a vector quantity that expresses the amount of dynamical rotation present in the electromagnetic field of the light. Indeed, a beam of light, while traveling approximately in a straight line, can also be rotating (or “spinning”, or “twisting”) around its own axis. This rotation, while not visible to the naked eye, can be revealed by the interaction of the light beam with matter. The total angular momentum of light (or, more generally, of the electromagnetic field and the other force fields) and matter is conserved in time. But there are actually two distinct forms of rotation of a light beam, one involving its polarization and the other its wavefront shape. These two forms of rotation are hence associated with two distinct forms of angular momentum, respectively named light spin angular momentum (SAM) and light orbital angular momentum (OAM).

text: The angular momentum of light is a

text: vector

text: quantity that expresses the amount of dynamical rotation present in the

text: electromagnetic field

text: of the

text: light

text: . Indeed, a beam of light, while traveling approximately in a straight line, can also be rotating (or “spinning”, or “twisting”) around its own axis. This rotation, while not visible to the naked

text: eye

text: , can be revealed by the interaction of the light beam with matter. The total angular momentum of light (or, more generally, of the

text: electromagnetic field

text: and the other

text: force

text: fields) and matter is conserved in time. But there are actually two distinct forms of rotation of a light beam, one involving its

text: polarization

text: and the other its

text: wavefront

text: shape. These two forms of rotation are hence associated with two distinct forms of angular momentum, respectively named

text: light spin angular momentum

text: (SAM) and

text: light orbital angular momentum

text: (OAM).

text: Although protection is a primary purpose of glazing, displaying an artwork is the primary purpose of framing it. Therefore, the least visible glazing best displays the artwork behind it. Visible light transmission is the primary measure of glass' invisibility, since the viewer actually sees the light, reflected from the artwork. Light transmission of glass is especially important in art framing, since light passes through the glass twice – once to illuminate the artwork, and then again, reflected from the artwork, as colors - before reaching the viewer.

text: Although protection is a primary purpose of glazing, displaying an artwork is the primary purpose of framing it. Therefore, the least visible glazing best displays the artwork behind it.

text: Visible light

text: transmission is the primary measure of glass' invisibility, since the viewer actually sees the light, reflected from the artwork. Light transmission of glass is especially important in art framing, since light passes through the glass twice – once to illuminate the artwork, and then again, reflected from the artwork, as colors - before reaching the viewer.

text: The composition of particulate matter that generally causes visual effects such as smog consists of sulfur dioxide, nitrogen oxides, carbon monoxide, mineral dust, organic matter, and elemental carbon also known as black carbon or soot. The particles are hygroscopic due to the presence of sulfur, and SO is converted to sulfate when high humidity and low temperatures are present. This causes the reduced visibility and yellow color.

text: The composition of particulate matter that generally causes visual effects such as smog consists of sulfur dioxide, nitrogen oxides, carbon monoxide, mineral dust, organic matter, and elemental carbon also known as black carbon or

text: soot

text: . The particles are hygroscopic due to the presence of sulfur, and SO is converted to sulfate when high humidity and low temperatures are present. This causes the reduced visibility and yellow color.

text: The major components of the cluster pair—stars, gas and the putative dark matter—behave differently during collision, allowing them to be studied separately.  The stars of the galaxies, observable in visible light, were not greatly affected by the collision, and most passed right through, gravitationally slowed but not otherwise altered.  The hot gas of the two colliding components, seen in X-rays, represents most of the baryonic, i.e. ordinary, matter in the cluster pair. The gases interact electromagnetically, causing the gases of both clusters to slow much more than the stars. The third component, the dark matter, was detected indirectly by the gravitational lensing of background objects.  In theories without dark matter, such as Modified Newtonian Dynamics (MOND), the lensing would be expected to follow the baryonic matter; i.e. the X-ray gas.  However, the lensing is strongest in two separated regions near (possibly coincident with) the visible galaxies.  This provides support for the idea that most of the mass in the cluster pair is in the form of two regions of dark matter, which bypassed the gas regions during the collision.  This accords with predictions of dark matter as only weakly interacting, other than via the gravitational force.

text: The major components of the cluster pair—

text: star

text: s,

text: gas

text: and the putative dark matter—behave differently during collision, allowing them to be studied separately.  The stars of the galaxies, observable in visible

text: light

text: , were not greatly affected by the collision, and most passed right through,

text: gravitationally

text: slowed but not otherwise altered.  The hot gas of the two colliding components, seen in

text: X-ray

text: s, represents most of the

text: baryon

text: ic, i.e. ordinary, matter in the cluster pair. The gases interact electromagnetically, causing the gases of both clusters to slow much more than the stars. The third component, the dark matter, was detected indirectly by the

text: gravitational lens

text: ing of background objects.  In

text: theories

text: without dark matter, such as

text: Modified Newtonian Dynamics

text: (MOND), the lensing would be expected to follow the baryonic matter; i.e. the X-ray gas.  However, the lensing is strongest in two separated regions near (possibly coincident with) the visible galaxies.  This provides support for the idea that most of the mass in the cluster pair is in the form of two regions of dark matter, which bypassed the gas regions during the collision.  This accords with predictions of dark matter as only weakly interacting, other than via the gravitational force.

text: These distinctions can be better understood in the light of Aquinas' understanding of matter and form, a hylomorphic ("matter/form") theory derived from Aristotle. In any given substance, matter and form are necessarily united, and each is a necessary aspect of that substance. However, they are conceptually separable. Matter represents what is changeable about the substance—what is potentially something else. For example, bronze matter is potentially a statue, or also potentially a cymbal. Matter must be understood as the matter of something. In contrast, form is what determines some particular chunk of matter to be a specific substance and no other. When Aquinas says that the human body is only partly composed of matter, he means the material body is only potentially a human being. The soul is what actualizes that potential into an existing human being. Consequently, the fact that a human body is live human tissue entails that a human soul is wholly present in each part of the human.

text: These distinctions can be better understood in the light of Aquinas' understanding of matter and form, a

text: hylomorphic

text: ("matter/form") theory derived from

text: Aristotle

text: . In any given substance, matter and form are necessarily united, and each is a necessary aspect of that substance. However, they are conceptually separable. Matter represents what is changeable about the substance—what is potentially something else. For example, bronze matter is potentially a statue, or also potentially a cymbal. Matter must be understood as the matter of something. In contrast, form is what determines some particular chunk of matter to be a specific substance and no other. When Aquinas says that the human body is only partly composed of matter, he means the material body is only potentially a human being. The soul is what actualizes that potential into an existing human being. Consequently, the fact that a human body is live human tissue entails that a human soul is wholly present in each part of the human.

text: In the more complicated scenario of multiple reflections, say with light travelling through a window, light is reflected both when going from air to glass and at the other side of the window when going from glass back to air. The size of the loss is the same in both cases. Light also may bounce from one surface to another multiple times, being partially reflected and partially transmitted each time it does so. In all, the combined reflection coefficient is given by . For glass in air, this is about 7.7%.

text: Tires are puncture-resistant for travelling without a pump and tools to fix a flat tire.  Width is normally medium to wide (1.5-1.75 inches; 38–44 mm), providing a balance of speed with durability and cushioning.  These are semi-slick road tires with shallow tread, such as Schwalbe Marathon tires.  Such tires are faster and quieter than mountain-bike tires, and more durable and reliable than road-racing tires. Reflective bands on the sidewalls make the wheels visible as wheels, not just as small reflectors.  This makes the bike more visible from side at night by cars without using reflective clothing and extra lights.

text: Tires

text: are puncture-resistant for travelling without a pump and tools to fix a flat tire.  Width is normally medium to wide (1.5-1.75 inches; 38–44 mm), providing a balance of speed with durability and cushioning.  These are semi-slick road tires with shallow tread, such as Schwalbe Marathon tires.  Such tires are faster and quieter than mountain-bike tires, and more durable and reliable than road-racing tires. Reflective bands on the sidewalls make the wheels visible as wheels, not just as small reflectors.  This makes the bike more visible from side at night by cars without using reflective clothing and extra lights.

text: In 1966, Lijn and Takis separated and Lijn moved to London where she invented kinetic clothing. She also began her series of rotating Linear Light Columns. These works combine surface variations made to metal cylinders, then wound with copper wire, with reflected light. The completed wire wound coils use reflected light to make visible invisible connections between time and frequency. These were followed by her series of works made with tank and gunsight prisms. Her work In Sua Memoria (1971–72) made in memory of her father epitomises her use of reflected light in a darkened space. As the art critic Jasia Reichardt observes: ‘There is an intersection (in Lijn’s work) at which science fiction, religion and quantum physics converge.’  And the writer Hilary Spurling states that: ‘Physics supplied Lijn with the syntax and grammar of an evolving kinetic language.Her subject was the structure and patterns of matter.’’ It was during this time that Lijn’s interest in Buddhism and in quantum and solid-state physics inspired her to write Crossing Map, an autobiographical prose poem which tracks an invisible human travelling at the speed of light and is illustrated by organic drawings.

text: In 1966, Lijn and

text: Takis

text: separated and Lijn moved to London where she invented kinetic clothing. She also began her series of rotating Linear Light Columns. These works combine surface variations made to metal cylinders, then wound with copper wire, with reflected light. The completed wire wound coils use reflected light to make visible invisible connections between time and frequency. These were followed by her series of works made with tank and gunsight prisms. Her work In Sua Memoria (1971–72) made in memory of her father epitomises her use of reflected light in a darkened space. As the art critic Jasia Reichardt observes: ‘There is an intersection (in Lijn’s work) at which science fiction, religion and quantum physics converge.’  And the writer

text: Hilary Spurling

text: states that: ‘Physics supplied Lijn with the syntax and grammar of an evolving kinetic language.Her subject was the structure and patterns of matter.’’ It was during this time that Lijn’s interest in

text: Buddhism

text: and in

text: quantum

text: and

text: solid-state physics

text: inspired her to write Crossing Map, an autobiographical prose poem which tracks an invisible human travelling at the speed of light and is illustrated by organic drawings.

text: The presence of electrons in matter changes the energy levels of the propagation eigenstates (mass eigenstates) of neutrinos due to charged current coherent forward scattering of the electron neutrinos (i.e., weak interactions). The coherent forward scattering is analogous to the electromagnetic process leading to the refractive index of light in a medium. This means that neutrinos in matter have a different effective mass than neutrinos in vacuum, and since neutrino oscillations depend upon the squared mass difference of the neutrinos, neutrino oscillations may be different in matter than they are in vacuum. With antineutrinos, the conceptual point is the same but the effective charge that the weak interaction couples to (called weak isospin) has an opposite sign. If the electron density of matter changes along the path of neutrinos, the mixing of neutrinos grows to maximum at some value of the density, and then turns back; it leads to resonant conversion of one type of neutrinos to other one.

text: The presence of

text: electron

text: s in matter changes the

text: energy level

text: s of the propagation

text: eigenstates

text: (mass eigenstates) of neutrinos due to

text: charged current

text: coherent forward scattering of the electron neutrinos (i.e.,

text: weak interactions

text: ). The coherent forward scattering is analogous to the electromagnetic process leading to the

text: refractive index

text: of light in a medium. This means that neutrinos in matter have a different effective mass than neutrinos in vacuum, and since neutrino oscillations depend upon the squared mass difference of the neutrinos, neutrino oscillations may be different in matter than they are in vacuum. With antineutrinos, the conceptual point is the same but the effective charge that the weak interaction couples to (called

text: weak isospin

text: ) has an opposite sign. If the electron density of matter changes along the path of neutrinos, the mixing of neutrinos grows to maximum at some value of the density, and then turns back; it leads to resonant conversion of one type of neutrinos to other one.

text: Class 1 defines the lowest visibility levele.g. High-visibility trousers with two 5 cm reflective bands around each leg. These become Class 3 when worn with a Class 3 jacket.

text: The first  laser was developed in 1980. This type of laser is likely to be tunable over a wide range of wavelengths (30 nm) in the visible spectrum. This is true even if the absorption phenomena occur on the side of shorter wavelengths and therefore limits the laser action at the red region of the electromagnetic spectrum from light emission. Solid state experiments with  suggest that the gaseous state is more suitable for the development of this type of laser. The measured amplification was correct in the solid state. The liquid state seems like an ideal dye laser although implementation seems complex and costly. Presently, the Cl laser has not been industrially developed. Unlike XeCl, the best chlorine donor is  while no laser action occurs when using HCl.

text: The first  laser was developed in 1980. This type of laser is likely to be tunable over a wide range of wavelengths (30 nm) in the

text: visible spectrum

text: . This is true even if the absorption phenomena occur on the side of shorter wavelengths and therefore limits the laser action at the red region of the

text: electromagnetic spectrum

text: from

text: light emission

text: . Solid state experiments with  suggest that the gaseous state is more suitable for the development of this type of laser. The measured amplification was correct in the solid state. The liquid state seems like an ideal

text: dye laser

text: although implementation seems complex and costly. Presently, the Cl laser has not been industrially developed. Unlike XeCl, the best chlorine donor is

text: while no laser action occurs when using HCl.

text: Two other issues that must be considered in setting up an absorption spectroscopy experiment include the optics used to direct the radiation and the means of holding or containing the sample material (called a cuvette or cell). For most UV, visible, and NIR measurements the use of precision quartz cuvettes are necessary. In both cases, it is important to select materials that have relatively little absorption of their own in the wavelength range of interest. The absorption of other materials could interfere with or mask the absorption from the sample. For instance, in several wavelength ranges it is necessary to measure the sample under vacuum or in a rare gas environment because gases in the atmosphere have interfering absorption features.

text: Two other issues that must be considered in setting up an absorption spectroscopy experiment include the

text: optics

text: used to direct the radiation and the means of holding or containing the sample material (called a

text: cuvette

text: or cell). For most UV, visible, and NIR measurements the use of precision quartz cuvettes are necessary. In both cases, it is important to select materials that have relatively little absorption of their own in the wavelength range of interest. The absorption of other materials could interfere with or mask the absorption from the sample. For instance, in several wavelength ranges it is necessary to measure the sample under

text: vacuum

text: or in a

text: rare gas

text: environment because gases in the

text: atmosphere

text: have interfering absorption features.

text: The Cathars believed that there were two principal powers in the Universe. One, God, was entirely good and dwelt in a condition of pure Spirit and Light, while the other, Satan/Lucifer, "the prince of this world" was entirely evil and ruled over the world of Matter, hence their rejection of physical pleasures. This dualism they drew from a particular reading of the Gospels, for example "That which is born of the flesh is flesh; and that which is born of the Spirit is Spirit" (Gospel of John 3:6). For the Cathars, Christ was an emissary of the Light sent into this world to lead humanity back to God. Each individual contained within them a shard of the Divine Light, the Angelic Soul which was trapped in a "garment" of flesh (the Body) by Lucifer. While confined in this "garment" of matter the Soul would forget its origin with God and instead find itself suffering the privations of this world. Cathars held to a Doctrine of Reincarnation, believing that the Soul was doomed to incarnate into this world time and again until through a process of spiritual growth and purification it was able to return to God through Christ and the Holy Spirit. According to the records of the Inquisition, it was believed that this process of death and rebirth towards final Perfection took place over seven lives:

text: The Cathars believed that there were two principal powers in the Universe. One,

text: God

text: , was entirely good and dwelt in a condition of pure Spirit and Light, while the other,

text: Satan

text: Lucifer

text: , "the prince of this world" was entirely evil and ruled over the world of Matter, hence their rejection of physical pleasures. This dualism they drew from a particular reading of the Gospels, for example "That which is born of the flesh is flesh; and that which is born of the Spirit is Spirit" (

text: Gospel of John

text: 3:6). For the Cathars,

text: Christ

text: was an emissary of the Light sent into this world to lead humanity back to God. Each individual contained within them a shard of the Divine Light, the Angelic Soul which was trapped in a "garment" of flesh (the Body) by

text: Lucifer

text: . While confined in this "garment" of matter the Soul would forget its origin with God and instead find itself suffering the privations of this world. Cathars held to a Doctrine of

text: Reincarnation

text: , believing that the Soul was doomed to incarnate into this world time and again until through a process of spiritual growth and purification it was able to return to God through Christ and the

text: Holy Spirit

text: . According to the records of the Inquisition, it was believed that this process of death and rebirth towards final Perfection took place over seven lives:

text: Gravitational lensing (or gravitational shear) is a consequence of the deflection of light rays caused by the presence of matter that locally modifies the curvature of space-time: light emitted by galaxies, and therefore observed images, are distorted as they pass close to matter lying along the line of sight. This matter is composed partly of visible galaxies but it is mostly dark matter. By measuring this "shear", the amount of dark matter can be inferred, furthering the understanding of how it is distributed in the universe.

text: Gravitational lensing (or gravitational shear) is a consequence of the deflection of light rays caused by the presence of matter that locally modifies the

text: curvature of space-time

text: : light emitted by galaxies, and therefore observed images, are distorted as they pass close to matter lying along the line of sight. This matter is composed partly of visible galaxies but it is mostly dark matter. By measuring this "shear", the amount of dark matter can be inferred, furthering the understanding of how it is distributed in the universe.

text: Next came the action sequences and the battle for the Enterprise, a phase the filmmakers dubbed "Borg Hell". Frakes directed the Borg scenes similar to a horror film, creating as much suspense as possible. To balance these elements he added more comedic elements to the Earth scenes, intended to momentarily relieve the audience of tension before building it up again. Leonetti reconfigured the lighting to reflect the takeover of the ship interiors. "When the ship gets Borgified, everything is changed into more of a squared-off, robotic look with sharp edges but rounded images," he explained. To give the corridor walls more shape, Leonetti lit them from underneath. Since the halls were so small and the ceilings would be visible in many of the shots, special attention was paid to hiding the light fixtures.

text: Next came the action sequences and the battle for the Enterprise, a phase the filmmakers dubbed "Borg Hell". Frakes directed the Borg scenes similar to a

text: horror film

text: , creating as much suspense as possible. To balance these elements he added more comedic elements to the Earth scenes, intended to momentarily relieve the audience of tension before building it up again. Leonetti reconfigured the lighting to reflect the takeover of the ship interiors. "When the ship gets Borgified, everything is changed into more of a squared-off, robotic look with sharp edges but rounded images," he explained. To give the corridor walls more shape, Leonetti lit them from underneath. Since the halls were so small and the ceilings would be visible in many of the shots, special attention was paid to hiding the light fixtures.

text: : intensity of light before absorption.

text: : intensity of light before absorption.

text: The shown image is a composite of separate exposures made by Hubble Space Telescope ACS and WFPC2 detectors and the Chandra ACIS detector. The Hubble images were taken on November 5, 2006, and June 6, 2007. The visible light images from Hubble showed  gravitational lensing which allowed astronomers to infer the distribution of total mass (both dark matter and normal matter)(colored in blue). The distribution of normal matter is mostly in the form of hot gas glowing brightly in X-rays (shown pink).  Its distribution was accurately mapped from Chandra data. From these it was possible to tell that most of the mass in the two blue regions was dark matter.

text: The shown image is a composite of separate exposures made by

text: Hubble Space Telescope

text: ACS and WFPC2 detectors and the

text: Chandra

text: ACIS detector. The Hubble images were taken on November 5, 2006, and June 6, 2007. The visible light images from Hubble showed

text: gravitational lensing

text: which allowed astronomers to infer the distribution of total mass (both dark matter and normal matter)(colored in blue). The distribution of normal matter is mostly in the form of hot gas glowing brightly in X-rays (shown pink).  Its distribution was accurately mapped from Chandra data. From these it was possible to tell that most of the mass in the two blue regions was dark matter.

text: Given an event E, the light cone classifies all events in spacetime into 5 distinct categories:

text: Photonics is the science of light (photon) generation, detection, and manipulation through emission, transmission, modulation, signal processing, switching, amplification, and detection/sensing. Though covering all light's technical applications over the whole spectrum, most photonic applications are in the range of visible and near-infrared light. The term photonics developed as an outgrowth of the first practical semiconductor light emitters invented in the early 1960s and optical fibers developed in the 1970s.

text: Photonics is the science of light (

text: photon

text: ) generation, detection, and manipulation through

text: emission

text: transmission

text: modulation

text: signal processing

text: , switching,

text: amplification

text: , and

text: detection/sensing

text: . Though covering all

text: light

text: 's technical applications over the whole

text: spectrum

text: , most photonic applications are in the range of visible and near-

text: infrared

text: light. The term photonics developed as an outgrowth of the first practical semiconductor light emitters invented in the early 1960s and optical fibers developed in the 1970s.

text: A video camera can be seen as an approximation of a pinhole camera, which means that each point in the image is illuminated by some (normally one) point in the scene in front of the camera, usually by means of light that the scene point reflects from a light source.  Each visible point in the scene is projected along a straight line that passes through the camera aperture and intersects the image plane.  This means that at a specific point in time, each point in the image refers to a specific point in the scene.  This scene point has a position relative to the camera, and if this relative position changes, it corresponds to a relative motion in 3D.  It is a relative motion since it does not matter if it is the scene point, or the camera, or both, that are moving.  It is only when there is a change in the relative position that the camera is able to detect that some motion has happened.  By projecting the relative 3D motion of all visible points back into the image, the result is the motion field, describing the apparent motion of each image point in terms of a magnitude and direction of velocity of that point in the image plane.  A consequence of this observation is that if the relative 3D motion of some scene points are along their projection lines, the corresponding apparent motion is zero.

text: A video camera can be seen as an approximation of a

text: pinhole camera

text: , which means that each point in the image is illuminated by some (normally one) point in the scene in front of the camera, usually by means of light that the scene point reflects from a light source.  Each visible point in the scene is projected along a straight line that passes through the camera aperture and intersects the image plane.  This means that at a specific point in time, each point in the image refers to a specific point in the scene.  This scene point has a position relative to the camera, and if this relative position changes, it corresponds to a relative motion in 3D.  It is a relative motion since it does not matter if it is the scene point, or the camera, or both, that are moving.  It is only when there is a change in the relative position that the camera is able to detect that some motion has happened.  By projecting the relative 3D motion of all visible points back into the image, the result is the

text: motion field

text: , describing the apparent motion of each image point in terms of a magnitude and direction of velocity of that point in the image plane.  A consequence of this observation is that if the relative 3D motion of some scene points are along their projection lines, the corresponding apparent motion is zero.

text: On the heights of the Schneifel is the former US radar station, Prüm Air Station, and the Schnee Eifel transmission tower  for terrestrial TV and VHF which, with a height of 224 m is clearly visible for miles.

text: On the heights of the Schneifel is the former US radar station, Prüm Air Station, and the Schnee Eifel transmission tower  for

text: terrestrial TV

text: and

text: VHF

text: which, with a height of 224 m is clearly visible for miles.

text: The aluminium gallium indium phosphide laser is a type of visible-light diode laser. Visible diode lasers emit wavelengths of red and green in the visible spectrum of electromagnetic radiation. The diode lasers consist of a semiconductor material in which the p-n junction forms the active medium.The AlGaInP laser emits wavelengths of 0.63-0.9 µm. Each of these wavelengths is used for different applications. Some of the other applications of the AlGaInP laser are listed below:

text: This color wheel demonstrates which color a compound will appear if it only has one absorption in the visible spectrum.  For example, if the compound absorbs red light, it will appear cyan.

text: This

text: color wheel

text: demonstrates which color a compound will appear if it only has one absorption in the visible spectrum.  For example, if the compound absorbs red light, it will appear cyan.

text: Prisms, mirrors, and lenses have a long history of altering the diffracted visible light that surrounds all. However, the control exhibited by these ordinary materials is limited. Moreover, the one material which is common among these three types of directors of light is conventional glass. Hence, these familiar technologies are constrained by the fundamental, physical laws of optics. With metamaterials in general, and the cloaking technology in particular, it appears these barriers disintegrate with advancements in materials and technologies never before realized in the natural physical sciences. These unique materials became notable because electromagnetic radiation can be bent, reflected, or skewed in new ways. The radiated light could even be slowed or captured before transmission. In other words, new ways to focus and project light and other radiation are being developed. Furthermore, the expanded optical powers presented in the science of cloaking objects appear to be technologically beneficial across a wide spectrum of devices already in use. This means that every device with basic functions that rely on interaction with the radiated electromagnetic spectrum could technologically advance. With these beginning steps a whole new class of optics has been established.

text: Prism

text: s,

text: mirror

text: s, and

text: lens

text: es have a long history of altering the diffracted visible light that surrounds all. However, the control exhibited by these ordinary materials is limited. Moreover, the one material which is common among these three types of directors of light is conventional

text: glass

text: . Hence, these familiar

text: technologies

text: are constrained by the fundamental, physical

text: laws of optics

text: . With metamaterials in general, and the cloaking technology in particular, it appears these barriers disintegrate with advancements in materials and technologies never before realized in the

text: natural physical sciences

text: . These unique materials became notable because electromagnetic radiation can be bent, reflected, or skewed in new ways. The radiated light could even be slowed or captured before transmission. In other words, new ways to focus and project light and other radiation are being developed. Furthermore, the expanded optical powers presented in the science of cloaking objects appear to be technologically beneficial across a wide spectrum of devices already in use. This means that every device with basic functions that rely on interaction with the radiated

text: electromagnetic spectrum

text: could technologically advance. With these beginning steps a whole new class of optics has been established.

text: Optical fingerprint imaging involves capturing a digital image of the print using visible light.  This type of sensor is, in essence, a specialized digital camera.  The top layer of the sensor, where the finger is placed, is known as the touch surface.  Beneath this layer is a light-emitting phosphor layer which illuminates the surface of the finger.  The light reflected from the finger passes through the phosphor layer to an array of solid state pixels (a charge-coupled device) which captures a visual image of the fingerprint.  A scratched or dirty touch surface can cause a bad image of the fingerprint.  A disadvantage of this type of sensor is the fact that the imaging capabilities are affected by the quality of skin on the finger.  For instance, a dirty or marked finger is difficult to image properly.  Also, it is possible for an individual to erode the outer layer of skin on the fingertips to the point where the fingerprint is no longer visible. It can also be easily fooled by an image of a fingerprint if not coupled with a "live finger" detector. However, unlike capacitive sensors, this sensor technology is not susceptible to electrostatic discharge damage.

text: Optical fingerprint imaging involves capturing a digital image of the print using

text: visible light

text: .  This type of sensor is, in essence, a specialized

text: digital camera

text: .  The top layer of the sensor, where the finger is placed, is known as the touch surface.  Beneath this layer is a light-emitting phosphor layer which illuminates the surface of the finger.  The light reflected from the finger passes through the phosphor layer to an array of

text: solid state

text: pixels (a

text: charge-coupled device

text: ) which captures a visual image of the fingerprint.  A scratched or dirty touch surface can cause a bad image of the fingerprint.  A disadvantage of this type of sensor is the fact that the imaging capabilities are affected by the quality of skin on the finger.  For instance, a dirty or marked finger is difficult to image properly.  Also, it is possible for an individual to erode the outer layer of skin on the fingertips to the point where the fingerprint is no longer visible. It can also be easily fooled by an image of a fingerprint if not coupled with a "live finger" detector. However, unlike capacitive sensors, this sensor technology is not susceptible to electrostatic discharge damage.

text: There are three types of light: ultraviolet (UV) light, infrared radiation and visible light. All three types are harmful to artifacts and the damage caused by all light is cumulative and irreversible. Exposure to light in all forms causes a chemical reaction to happen within the molecular level of an artifact. Light exposure can cause textiles to weaken and fade, dyes and paints to darken or change color, and paper to become weak, bleached, yellowed or darkened.

text: There are three types of light:

text: ultraviolet

text: (UV) light,

text: infrared radiation

text: and

text: visible light

text: . All three types are harmful to artifacts and the damage caused by all light is cumulative and irreversible. Exposure to light in all forms causes a chemical reaction to happen within the molecular level of an artifact. Light exposure can cause textiles to weaken and fade, dyes and paints to darken or change color, and paper to become weak, bleached, yellowed or darkened.

text: Water is responsible for the attenuation of light due to absorption so use of a dive light will improve a divers underwater vision. As the depth increases, more light is absorbed by the water. Color absorption depends on the purity of the water - pure water is most transparent to blue frequencies, but impurities may reduce this significantly. Color vision is also affected by turbidity and larger particulate matter.

text: Water is responsible for the attenuation of light due to absorption so use of a dive light will improve a divers

text: underwater vision

text: . As the depth increases, more light is absorbed by the water. Color absorption depends on the purity of the water - pure water is most transparent to blue frequencies, but impurities may reduce this significantly. Color vision is also affected by

text: turbidity

text: and larger particulate matter.

text: Edward Hopper had a lifelong interest in capturing the effect of light on the objects it touched, including the nighttime effect of artificial, man-made light spilling out of windows, doorways and porches. Nighthawks was probably Hopper's most ambitious essay in capturing the night-time effects of man-made light. For one thing, the diner's plate-glass windows cause significant light to spill out onto the sidewalk and the brownstones on the far side of the street. As well, interior light comes from more than a single lightbulb, with the result that multiple shadows are cast, and some spots are brighter than others as a consequence of being lit from more than one angle. Across the street, the line of shadow caused by the upper edge of the diner window is clearly visible towards the top of the painting.  These windows, and the ones below them as well, are partly lit by an unseen streetlight, which projects its own mix of light and shadow. As a final note, the bright interior light causes some of the surfaces within the diner to be reflective. This is clearest in the case of the right-hand edge of the rear window, which reflects a vertical yellow band of interior wall, but fainter reflections can also be made out, in the counter-top, of three of the diner's occupants. None of these reflections would be visible in daylight.

text: Edward Hopper

text: had a lifelong interest in capturing the effect of light on the objects it touched, including the nighttime effect of artificial, man-made light spilling out of windows, doorways and porches.

text: Nighthawks

text: was probably Hopper's most ambitious essay in capturing the night-time effects of man-made light. For one thing, the diner's plate-glass windows cause significant light to spill out onto the sidewalk and the brownstones on the far side of the street. As well, interior light comes from more than a single lightbulb, with the result that multiple shadows are cast, and some spots are brighter than others as a consequence of being lit from more than one angle. Across the street, the line of shadow caused by the upper edge of the diner window is clearly visible towards the top of the painting.  These windows, and the ones below them as well, are partly lit by an unseen streetlight, which projects its own mix of light and shadow. As a final note, the bright interior light causes some of the surfaces within the diner to be reflective. This is clearest in the case of the right-hand edge of the rear window, which reflects a vertical yellow band of interior wall, but fainter reflections can also be made out, in the counter-top, of three of the diner's occupants. None of these reflections would be visible in daylight.

text: The principal and manifest consequence of chiral symmetry breaking is the generation of 99% of the mass of nucleons, and hence the bulk of all visible matter, out of very light quarks. For example, in the proton, of mass m ≈ 938 MeV, the valence quarks, two up quarks with m ≈ 2.3 MeV and one down quark with m ≈ 4.8 MeV, only contribute about 9.4 MeV to the proton's mass. The source of the bulk of the proton's mass is quantum chromodynamics binding energy, which arises out of QCD chiral symmetry breaking.

text: The principal and manifest consequence of chiral symmetry breaking is the generation of 99% of the mass of

text: nucleons

text: , and hence the bulk of all

text: visible matter

text: , out of very light

text: quarks

text: . For example, in the

text: proton

text: , of mass m ≈ 938

text: MeV

text: , the

text: valence quark

text: s, two

text: up quark

text: s with m ≈ 2.3 MeV and one

text: down quark

text: with m ≈ 4.8 MeV, only contribute about 9.4 MeV to the proton's mass. The source of the bulk of the proton's mass is

text: quantum chromodynamics binding energy

text: , which arises out of QCD chiral symmetry breaking.

text: Intact beta-lactam antibiotics act as an analog to penicillin binding proteins (PBPs) involved in peptidoglycan synthesis. Beta-lactamases hydrolyze the amide bond between the carbonyl carbon and the nitrogen in the beta-lactam ring of susceptible beta-lactams and members of beta-lactam subclasses (including certain cephalosporins). After hydrolysis of the amide bond, the antibiotic lacks the ability to mimic bacterial PBPs and is rendered useless. Visual detection of this process is essentially impossible with most cephalosporins because the shift of ultraviolet absorption from the intact versus hydrolyzed product occurs outside of the visible spectrum. Hydrolysis of nitrocefin however, produces a shift of ultraviolet absorption inside the visible light spectrum from intact (yellow) nitrocefin (~380 nm) to degraded (red) nitrocefin (~500 nm) allowing visual detection of beta-lactamase activity on a macroscopic level.

text: Intact

text: beta-lactam

text: antibiotics act as an analog to

text: penicillin binding proteins

text: (PBPs) involved in

text: peptidoglycan

text: synthesis.

text: Beta-lactamases

text: hydrolyze the

text: amide

text: bond between the

text: carbonyl

text: carbon

text: and the

text: nitrogen

text: in the

text: beta-lactam

text: ring of susceptible beta-lactams and members of

text: beta-lactam

text: subclasses (including certain cephalosporins). After hydrolysis of the amide bond, the antibiotic lacks the ability to mimic bacterial PBPs and is rendered useless. Visual detection of this process is essentially impossible with most

text: cephalosporin

text: s because the shift of

text: ultraviolet

text: absorption from the intact versus hydrolyzed product occurs outside of the

text: visible spectrum

text: . Hydrolysis of nitrocefin however, produces a shift of

text: ultraviolet

text: absorption inside the visible light spectrum from intact (yellow) nitrocefin (~380 nm) to degraded (red) nitrocefin (~500 nm) allowing visual detection of

text: beta-lactamase

text: activity on a macroscopic level.

text: Through the control of percent composition of 2-5 nm platinum nanoparticles on SiO, Zhang et al. modeled distinct absorption peaks attributed to platinum in the visible range, distinct from the conventional SPR absorption. This research attributed these absorption features to the generation and transfer of hot electrons from the platinum nanoparticles to the semiconductive material.  Interestingly, the addition of small platinum nanoparticles on semiconductors such as TiO increases the photocatalytic oxidation activity under visible light irradiation. These concepts suggest the possible role of platinum nanoparticles in the development of solar energy conversion using metal nanoparticles. By changing the size, shape and environment of metal nanoparticles, their optical properties can be used for electrontic, catalytic, sensing, and photovoltaic applications.

text: A number of matters came into public focus during the hearings process. One of them was the shape and locations of the two proposed ventilation shaft buildings near the northern and southern tunnel entries, and their likely effect on local visual amenity (with the shafts, at 25m-27m height, proposed to tower visibly over surrounding suburban areas) and local air pollution levels (where an indepependent report considered that the NZTA had been too optimistic in terms of pollution conditions during traffic jams and due to induced demand). Other matters included effects on local neighbourhoods, even those where demolition was not expected, such as for several apartment buildings directly adjacent to a multi-year construction site.

text: A number of matters came into public focus during the hearings process. One of them was the shape and locations of the two proposed ventilation shaft buildings near the northern and southern tunnel entries, and their likely effect on local visual amenity (with the shafts, at 25m-27m height, proposed to tower visibly over surrounding suburban areas) and local air pollution levels (where an indepependent report considered that the NZTA had been too optimistic in terms of pollution conditions during traffic jams and due to

text: induced demand

text: ). Other matters included effects on local neighbourhoods, even those where demolition was not expected, such as for several apartment buildings directly adjacent to a multi-year construction site.

text: Light refracted or reflected causes patterns called caustics, usually visible as concentrated patches of light on nearby surfaces. For example, as light rays pass through a wine glass sitting on a table, they are refracted and patterns of light are visible on the table. Photon mapping can trace the paths of individual photons to model where these concentrated patches of light will appear.

text: Light

text: refracted

text: or

text: reflected

text: causes patterns called

text: caustics

text: , usually visible as concentrated patches of light on nearby surfaces. For example, as light rays pass through a wine glass sitting on a table, they are refracted and patterns of light are visible on the table. Photon mapping can trace the paths of individual photons to model where these concentrated patches of light will appear.

text: During heat treating, a blacksmith causes phase changes in the iron-carbon system in order to control the material's mechanical properties, often using the annealing, quenching, and tempering processes. In this context, the color of light, or "blackbody radiation," emitted by the workpiece is an approximate gauge of temperature. Temperature is often gauged by watching the color temperature of the work, with the transition from a deep cherry-red to orange-red ( to ) corresponding to the formation of austenite in medium and high-carbon steel. In the visible spectrum, this glow increases in brightness as temperature increases, and when cherry-red the glow is near its lowest intensity and may not be visible in ambient light. Therefore, blacksmiths usually austenize steel in low-light conditions, to help accurately judge the color of the glow.

text: During

text: heat treating

text: , a

text: blacksmith

text: causes phase changes in the iron-carbon system in order to control the material's mechanical properties, often using the annealing, quenching, and tempering processes. In this context, the color of light, or "

text: blackbody radiation

text: ," emitted by the workpiece is an approximate

text: gauge of temperature

text: . Temperature is often gauged by watching the

text: color temperature

text: of the work, with the transition from a deep cherry-red to orange-red ( to ) corresponding to the formation of austenite in medium and high-carbon steel. In the visible spectrum, this glow increases in brightness as temperature increases, and when cherry-red the glow is near its lowest intensity and may not be visible in ambient light. Therefore, blacksmiths usually austenize steel in low-light conditions, to help accurately judge the color of the glow.

text: Spectroscopic methods for observing the absorption of electromagnetic radiation in the visible spectrum were known as early as the 1860s.Scientists had observed that light traveling through a medium would be absorbed at different wavelengths, depending on the matter-composition of the medium involved.  A white light source would emit light at multiple wavelengths over a range of frequencies.  A prism could be used to separate a light source into specific wavelengths. Shining the light through a sample of a material would cause some wavelengths of light to be absorbed, while others would be unaffected and continue to be transmitted.  Wavelengths in the resulting absorption spectrum would differ depending upon the atomic and molecular  composition if the material involved.

text: Spectroscopic methods for observing the

text: absorption

text: of

text: electromagnetic radiation

text: in the

text: visible spectrum

text: were known as early as the 1860s.Scientists had observed that light traveling through a

text: medium

text: would be absorbed at different wavelengths, depending on the matter-composition of the medium involved.  A white light source would emit light at multiple wavelengths over a range of frequencies.  A prism could be used to separate a light source into specific wavelengths. Shining the light through a sample of a material would cause some wavelengths of light to be absorbed, while others would be unaffected and continue to be transmitted.  Wavelengths in the resulting

text: absorption spectrum

text: would differ depending upon the

text: atom

text: ic and

text: molecular

text: composition if the material involved.

text: A two-row Chicago-style Sillitoe tartan is borne on the high-visibility vests of the Vancouver Police and Metro Vancouver Transit Police (along the edges of the horizontal and vertical reflective strips), but not on their high-visibility jackets nor other uniforms.

text: A two-row Chicago-style Sillitoe tartan is borne on the high-visibility vests of the

text: Vancouver Police

text: and

entity_name: South Coast British Columbia Transportation Authority Police Service

text: Metro Vancouver Transit Police

text: (along the edges of the horizontal and vertical reflective strips), but not on their

text: high-visibility jacket

text: s nor other uniforms.

text: The main purpose of matte glass is to transform the specular reflection into reflection haze. So-called "scattering" of the reflected light renders reflected images blurry, so that distinct reflected shapes and sources of light do not distract from the art viewing experience. Scattering the light does not reduce the reflection or absorption, which remain at the level of the glass substrate. There are several ways of making the glass surface matte – from pressing the pattern when the glass is still soft to fine etching of the glass surface by acid. The quality of matte glass is usually determined by its gloss factor or haze factor.

text: The main purpose of

text: matte

text: glass is to transform the

text: specular reflection

text: into

text: reflection haze

text: . So-called "

text: scattering

text: " of the reflected light renders reflected images blurry, so that distinct reflected shapes and sources of light do not distract from the art viewing experience. Scattering the light does not reduce the

text: reflection

text: or

text: absorption

text: , which remain at the level of the glass substrate. There are several ways of making the glass surface matte – from pressing the pattern when the glass is still soft to fine etching of the glass surface by acid. The quality of matte glass is usually determined by its gloss factor or haze factor.

text: The constant speed of light in a vacuum (customarily described with the letter "c") can be derived from Maxwell's equations, which are consistent with the theory of special relativity. Einstein's 1905 theory of special relativity, however, which flows from the observation that the speed of light is constant no matter how fast the observer is moving, showed that the theoretical result implied by Maxwell's equations has profound implications far beyond electromagnetism on the very nature of time and space.

text: The constant speed of light in a vacuum (customarily described with the letter "c") can be derived from Maxwell's equations, which are consistent with the theory of special relativity.

text: Einstein

text: 's 1905 theory of

text: special relativity

text: , however, which flows from the observation that the

text: speed of light

text: is constant no matter how fast the observer is moving, showed that the theoretical result implied by Maxwell's equations has profound implications far beyond electromagnetism on the very nature of time and space.

text: , and Einstein's considerations were independent from assumptions about the constitution of matter. By this equivalence, Poincaré's radiation paradox can be solved without using "compensating forces", because the mass of matter itself (not the non-electromagnetic aether fluid as suggested by Poincaré) is increased or diminished by the mass of electromagnetic energy in the course of the emission/absorption process. Also the idea of an electromagnetic explanation of gravitation was superseded in the course of developing general relativity.

text: , and Einstein's considerations were independent from assumptions about the constitution of matter. By this equivalence, Poincaré's radiation paradox can be solved without using "compensating forces", because the mass of matter itself (not the non-electromagnetic aether fluid as suggested by Poincaré) is increased or diminished by the mass of electromagnetic energy in the course of the emission/absorption process. Also the idea of an electromagnetic explanation of gravitation was superseded in the course of developing

text: general relativity

text: The elements – that is, ordinary (baryonic) matter made of protons, neutrons, and electrons, are only a small part of the content of the Universe. Cosmological observations suggest that only 4.6% of the universe's energy (including the mass contributed by energy, E = mc² ↔ m = E / c²) comprises the visible baryonic matter that constitutes stars, planets, and living beings. The rest is made up of dark energy (68%) and dark matter (27%). These are forms of matter and energy believed to exist on the basis of scientific theory and observational deductions, but they have not been directly observed and their nature is not well understood.

text: The elements – that is, ordinary (

text: baryon

text: ic) matter made of

text: proton

text: s,

text: neutron

text: s, and

text: electron

text: s, are only a small part of the content of the

text: Universe

text: Cosmological observations

text: suggest that only 4.6% of the universe's energy (including the mass contributed by energy, E = mc² ↔ m = E / c²) comprises the visible

text: baryon

text: ic

text: matter

text: that constitutes

text: star

text: s,

text: planets

text: , and

text: living

text: beings. The rest is made up of

text: dark energy

text: (68%) and

text: dark matter

text: (27%). These are forms of matter and energy believed to exist on the basis of

text: scientific theory

text: and observational

text: deduction

text: s, but they have not been directly observed and their nature is not well understood.

text: Internal combustion engines found in passenger automobiles are able to operate over a relatively wide range of speeds. A close-ratio type of transmission is designed to allow an engine to remain in a relatively narrow operating speed. Alternately, a wide-ratio transmission requires the engine to operate over a greater speed range, but requires less shifting and allows a wider range of output speeds.  Close-ratio transmissions are generally offered in sports cars, in which the engine is tuned for maximum power in a narrow range of operating speeds and the driver can be expected to enjoy shifting often to keep the engine in its power band.

text: Internal combustion engines found in passenger automobiles are able to operate over a relatively wide range of speeds. A close-ratio type of transmission is designed to allow an engine to remain in a relatively narrow operating speed. Alternately, a wide-ratio transmission requires the engine to operate over a greater speed range, but requires less shifting and allows a wider range of output speeds.  Close-ratio transmissions are generally offered in

text: sports car

text: s, in which the engine is tuned for maximum power in a narrow range of operating speeds and the driver can be expected to enjoy shifting often to keep the engine in its

text: power band

text: MTA has embarked on various measures to increase visibility of Orange Line Metroliners, including installing white LED strobes on each side of the vehicle to make them appear as if an emergency vehicle was crossing the red-lighted intersections. Drivers' tactics include slowing to approximately  at intersections with poor cross-traffic visibility or blind spots. In addition, the police department heavily patrols the route, with officers in marked cruisers and motorcycles distributing red-light citations.

text: The reflectivity of the mirror coating can be measured using a reflectometer and for a particular metal it will be different for different wavelengths of light. This is exploited in some optical work to make cold mirrors and hot mirrors. A cold mirror is made by using a transparent substrate and choosing a coating material that is more reflective to visible light and more transmissive to infrared light.

text: The reflectivity of the mirror coating can be measured using a

text: reflectometer

text: and for a particular metal it will be different for different wavelengths of light. This is exploited in some

text: optical

text: work to make

text: cold mirror

text: s and

text: hot mirror

text: s. A cold mirror is made by using a transparent substrate and choosing a coating material that is more reflective to visible light and more transmissive to

text: infrared

text: light.

text: Acoustic waves are reflected by walls or other hard surfaces, such as mountains and privacy fences. The reason of reflection may be explained as a discontinuity in the propagation medium. This can be heard when the reflection returns with sufficient magnitude and delay to be perceived distinctly.When sound, or the echo itself, is reflected multiple times from multiple surfaces, the echo is characterized as a reverberation.

text: Acoustic waves are reflected by walls or other hard surfaces, such as mountains and privacy fences. The reason of reflection may be explained as a discontinuity in the

text: propagation

text: medium

text: . This can be heard when the reflection returns with sufficient magnitude and

text: delay

text: to be perceived distinctly.When sound, or the echo itself, is reflected multiple times from multiple surfaces, the echo is characterized as a

text: reverberation

text: NGC 4555 is a solitary elliptical galaxy about 40,000 parsecs (125,000 light-years) across, and about 310 million light years distant. Observations by the Chandra X-ray Observatory have shown it to be surrounded by a halo of hot gas about 120,000 parsecs across. The hot gas has a temperature of around 10,000,000 kelvins. The galaxy is one of the few elliptical galaxies proven to have significant amounts of dark matter. Large amounts of dark matter are necessary to prevent the gas from escaping the galaxy; the visible mass clearly is not large enough to hold such an extensive gas halo. The dark matter halo is estimated to have 10 times the mass of the stars in the galaxy.

text: NGC 4555 is a solitary

text: elliptical galaxy

text: about 40,000

text: parsec

text: s (125,000

text: light-year

text: s) across, and about 310 million light years distant. Observations by the

text: Chandra X-ray Observatory

text: have shown it to be surrounded by a

text: halo

text: of hot gas about 120,000 parsecs across. The hot gas has a temperature of around 10,000,000

text: kelvin

text: s. The galaxy is one of the few elliptical galaxies proven to have significant amounts of

text: dark matter

text: . Large amounts of dark matter are necessary to prevent the gas from escaping the galaxy; the visible mass clearly is not large enough to hold such an extensive gas halo. The dark matter halo is estimated to have 10 times the mass of the stars in the galaxy.

text: Absorption of light and other material properties of diamond are highly dependent upon nitrogen content and aggregation state. Although all aggregate configurations cause absorption in the infrared, diamonds containing aggregated nitrogen are usually colorless, i.e. have little absorption in the visible spectrum. The four main nitrogen forms are as follows:

text: Absorption of light and other material properties of diamond are highly dependent upon nitrogen content and aggregation state. Although all aggregate configurations cause absorption in the

text: infrared

text: , diamonds containing aggregated nitrogen are usually colorless, i.e. have little absorption in the visible spectrum. The four main nitrogen forms are as follows:

text: Ixion is moderately red (slightly redder than 50000 Quaoar) in the visible light. It also has a higher albedo (>0.15) than the mid-sized red cubewanos. There may be an absorption feature at the wavelength of 0.8 μm in its spectrum, which is commonly attributed to the alteration of surface materials by water. In the near-infrared the spectrum of Ixion is flat and featureless. Water ice absorption bands at 1.5 and 2 μm are absent. This is in contrast to Varuna, which has a red spectral slope in the near-infrared as well as prominent water absorption bands. Both visible and infrared spectroscopic results indicate that Ixion's surface is a mixture of water ice, dark carbon and tholin, which is a heteropolymer formed by irradiation of clathrates of water and organic compounds. The Very Large Telescope (VLT) has checked Ixion for cometary activity, but did not detect a coma. Ixion is currently about 41 AU from the Sun, and it is possible that Ixion could develop a coma or temporary atmosphere when it is closer to perihelion.

text: Ixion is moderately red (slightly redder than

text: 50000 Quaoar

text: ) in the

text: visible light

text: . It also has a higher

text: albedo

text: (>0.15) than the mid-sized red

text: cubewano

text: s. There may be an absorption feature at the wavelength of 0.8 μm in its spectrum, which is commonly attributed to the alteration of surface materials by water. In the

text: near-infrared

text: the spectrum of Ixion is flat and featureless. Water ice

text: absorption band

text: s at 1.5 and 2 μm are absent. This is in contrast to

text: Varuna

text: , which has a red

text: spectral slope

text: in the near-infrared as well as prominent water absorption bands. Both visible and infrared

text: spectroscopic

text: results indicate that Ixion's surface is a mixture of water ice, dark

text: carbon

text: and

text: tholin

text: , which is a

text: heteropolymer

text: formed by irradiation of

text: clathrate

text: s of

text: water

text: and

text: organic compound

text: s. The

text: Very Large Telescope

text: (VLT) has checked Ixion for cometary activity, but did not detect a

text: coma

text: . Ixion is currently about 41 AU from the Sun, and it is possible that Ixion could develop a coma or temporary atmosphere when it is closer to

text: perihelion

text: As opposite to air, water attenuates light exponentially. This results in hazy images with very low contrast. The main reasons for light attenuation are light absorption (where energy is removed from the light) and light scattering, by which the direction of light is changed. Light scattering can further be divided into forward scattering, which results in an increased blurriness and backward scattering that limits the contrast and is responsible for the characteristic veil of underwater images. Both scattering and attenuation are heavily influenced by the amount of organic matter dissolved in the water.

text: Wood identified a very low ultraviolet albedo (reflectivity, that is most of the ultraviolet is absorbed) region in the Aristarchus Plateau region of the Moon which he suggested was due to high sulphur. The area continues to be called Wood's Spot. In 1909, Wood constructed the first practical liquid mirror astronomical telescope, by spinning mercury to form a paraboloidal shape, and investigated its benefits and limitations. Wood has been described as the "father of both infrared and ultraviolet photography". Though the discovery of electromagnetic radiation beyond the visible spectrum and the development of photographic emulsions capable of recording them pre-date Wood, he was the first to intentionally produce photographs with both infrared and ultraviolet radiation.   In 1903 he developed a filter, Wood's glass, that was opaque to visible light but transparent to both ultraviolet and infrared, and is used in modern-day black lights.   He used it for ultraviolet photography but also suggested its use for secret communication. He was also the first person to photograph ultraviolet fluorescence. He also developed an ultraviolet lamp, which is widely known as the Wood's lamp in medicine. The slightly surreal glowing appearance of foliage in infrared photographs is called the Wood effect.

text: Wood identified a very low ultraviolet

text: albedo

text: (reflectivity, that is most of the ultraviolet is absorbed) region in the

text: Aristarchus Plateau

text: region of the Moon which he suggested was due to high sulphur. The area continues to be called Wood's Spot. In 1909, Wood constructed the first practical

text: liquid mirror

text: astronomical telescope, by spinning mercury to form a

text: paraboloid

text: al shape, and investigated its benefits and limitations. Wood has been described as the "father of both infrared and ultraviolet photography". Though the discovery of

text: electromagnetic radiation

text: beyond the

text: visible spectrum

text: and the development of

text: photographic emulsion

text: s capable of recording them pre-date Wood, he was the first to intentionally produce photographs with both

text: infrared

text: and

text: ultraviolet

text: radiation.   In 1903 he developed a

text: filter

text: Wood's glass

text: , that was opaque to visible light but transparent to both ultraviolet and

text: infrared

text: , and is used in modern-day

text: black light

text: s.   He used it for ultraviolet photography but also suggested its use for secret communication. He was also the first person to photograph ultraviolet

text: fluorescence

text: . He also developed an ultraviolet lamp, which is widely known as the

text: Wood's lamp

text: in medicine. The slightly

text: surreal

text: glowing appearance of foliage in infrared photographs is called the Wood effect.

text: In acoustics, reflection causes echoes and is used in sonar. In geology, it is important in the study of seismic waves. Reflection is observed with surface waves in bodies of water. Reflection is observed with many types of electromagnetic wave, besides visible light. Reflection of VHF and higher frequencies is important for radio transmission and for radar. Even hard X-rays and gamma rays can be reflected at shallow angles with special "grazing" mirrors.

text: In

text: acoustics

text: , reflection causes

text: echoes

text: and is used in

text: sonar

text: . In geology, it is important in the study of

text: seismic wave

text: s. Reflection is observed with

text: surface wave

text: s in bodies of water. Reflection is observed with many types of

text: electromagnetic wave

text: , besides

text: visible light

text: . Reflection of

text: VHF

text: and higher frequencies is important for

text: radio

text: transmission and for

text: radar

text: . Even

text: hard X-ray

text: s and

text: gamma ray

text: s can be reflected at shallow angles with special "grazing" mirrors.

text: Several syntheses of oxoiron(IV) species have been  reported. These compounds model biological complexes such as cytochrome P450, NO synthase, and isopenicillin N synthase.  Two such reported compounds are thiolate-ligated oxoiron(IV) and cyclam-acetate oxoiron(IV).Thiolate-ligated oxoiron(IV) is formed by the oxidation of a precursor, [Fe(TMCS)](PF) (TMCS = 1-mercaptoethyl-4,8,11-trimethyl-1,4,8,11-tetraza cyclotetradecane), and 3-5 equivalents of HO at -60 ˚C in methanol.  The iron(IV) compound is deep blue in color and shows intense absorption features at 460 nm, 570 nm, 850 nm, and 1050 nm.  This species Fe(=O)(TMCS)+ is stable at -60 ˚C, but decomposition is reported as temperature increases. Compound 2 was identified by Mössbauer spectroscopy, high resolution electrospray ionization mass spectrometry (ESI-MS), x-ray absorption spectroscopy, x-ray absorption fine structure (EXAFS), UV-visible spectroscopy (UV-vis), Fourier transform infrared spectroscopy (FT-IR), and results were compared to DFT-calculations.

text: Several syntheses of oxoiron(IV) species have been  reported. These compounds model biological complexes such as

text: cytochrome P450

text: NO synthase

text: , and isopenicillin N synthase.  Two such reported compounds are thiolate-ligated oxoiron(IV) and cyclam-acetate oxoiron(IV).Thiolate-ligated oxoiron(IV) is formed by the oxidation of a precursor, [Fe(TMCS)](PF) (TMCS = 1-mercaptoethyl-4,8,11-trimethyl-1,4,8,11-tetraza cyclotetradecane), and 3-5 equivalents of HO at -60 ˚C in

text: methanol

text: .  The iron(IV) compound is deep blue in color and shows intense absorption features at 460 nm, 570 nm, 850 nm, and 1050 nm.  This species Fe(=O)(TMCS)+ is stable at -60 ˚C, but decomposition is reported as temperature increases. Compound 2 was identified by

text: Mössbauer spectroscopy

text: , high resolution electrospray ionization mass spectrometry (

text: ESI-MS

text: x-ray absorption spectroscopy

text: , x-ray absorption fine structure (

text: EXAFS

text: UV-visible spectroscopy

text: (UV-vis), Fourier transform infrared spectroscopy (

text: FT-IR

text: ), and results were compared to

text: DFT-calculations

text: Second-generation CRX buyers could choose between three different trim levels: The standard (unlabeled, sometimes called the "DX") with the 16-valve 1493 cc "D15B2" engine and dual-point fuel injection (DPFI), the HF ("high fuel efficiency") model with the eight-valve 1493 cc "D15B6" engine and multi-point fuel injection (MPFI), or the Si (sport injected) model with the 16-valve 1590 cc "D16A6" engine and MPFI. "DX" models were available with an automatic transmission, all others had five-speed manuals. A modification was made to the rear of the vehicle on all second generation vehicles in that a glass panel was installed on the upper half of the rear of the vehicle, above the tail lights which aided in rearward visibility in addition to the glass hatchback. This panel is heavily stippled black.

text: As a consequence of the definition, the speed of light in matter is

text: As a consequence of the definition, the

text: speed of light

text: in matter is

text: A UV coating is used to reduce the transmission of light in the ultraviolet spectrum. UV-B radiation increases the likelihood of cataracts, while long-term exposure to UV-A radiation can damage the retina. DNA damage from UV light is cumulative and irreversible. Some materials such as Trivex and Polycarbonate, naturally block most UV light; they have UV-cutoff wavelengths just outside the visible range, and do not benefit from the application of a UV coating.  Many modern anti-reflective coatings also block UV.

text: A UV coating is used to reduce the transmission of light in the

text: ultraviolet

text: spectrum.

text: UV-B

text: radiation increases the likelihood of

text: cataracts

text: , while long-term exposure to

text: UV-A

text: radiation can damage the

text: retina

text: . DNA damage from UV light is cumulative and irreversible. Some materials such as

text: Trivex

text: and

text: Polycarbonate

text: , naturally block most UV light; they have UV-cutoff wavelengths just outside the visible range, and do not benefit from the application of a UV coating.  Many modern anti-reflective coatings also block UV.

text: The dispersion of the refractive index is a fundamental property of matter.  It may be thought of as the result of the relative proximity of the harmonic frequencies of the outer shell electrons in a compound to the frequencies of visible light.  The harmonic frequency of the bonding electron is the result of the energy of that bond.  If the bond is very strong the frequency will be very high. The higher the frequency the less effect the difference in frequencies from blue to red will have on the refractive index.  For the relatively high energy bonds in most inorganic solids this means their refractive indices change very little over the visible range of frequencies.  The refractive indices of organic compounds on the other hand, with their lower bonding energies, change significantly over the visible range.  This difference in dispersion is the basis of the Christiansen effect and the dispersion staining methods.

text: The hidden room may be an identical mirror-image of the main room, so that its reflected image matches the main rooms; this approach is useful in making objects seem to appear or disappear. This illusion can also be used to make one object or person reflected in the mirror appear to morph into another behind the glass (or vice versa). This is the principle behind the Girl-to-Gorilla trick found in old carnival sideshows. The hidden room may instead be painted black, with only light-colored objects in it. In this case when light is cast on the room, only the light objects reflect the light and appear as ghostly translucent images superimposed in the visible room. This can be used to make objects appear to float in space.

text: The hidden room may be an identical mirror-image of the main room, so that its reflected image matches the main rooms; this approach is useful in making objects seem to appear or disappear. This illusion can also be used to make one object or person reflected in the mirror appear to

text: morph

text: into another behind the glass (or vice versa). This is the principle behind the Girl-to-Gorilla trick found in old carnival

text: sideshow

text: s. The hidden room may instead be painted black, with only light-colored objects in it. In this case when light is cast on the room, only the light objects reflect the light and appear as ghostly translucent images superimposed in the visible room. This can be used to make objects appear to float in space.

text: Different fields of science use the term matter in different, and sometimes incompatible, ways. Some of these ways are based on loose historical meanings, from a time when there was no reason to distinguish mass and matter. As such, there is no single universally agreed scientific meaning of the word "matter". Scientifically, the term "mass" is well-defined, but "matter" is not. Sometimes in the field of physics "matter" is simply equated with particles that exhibit rest mass (i.e., that cannot travel at the speed of light), such as quarks and leptons. However, in both physics and chemistry, matter exhibits both wave-like and particle-like properties, the so-called wave–particle duality.

text: Different fields of science use the term matter in different, and sometimes incompatible, ways. Some of these ways are based on loose historical meanings, from a time when there was no reason to distinguish mass and matter. As such, there is no single universally agreed scientific meaning of the word "matter". Scientifically, the term "mass" is well-defined, but "matter" is not. Sometimes in the field of physics "matter" is simply equated with particles that exhibit rest mass (i.e., that cannot travel at the speed of light), such as quarks and leptons. However, in both

text: physics

text: and

text: chemistry

text: , matter exhibits both

text: wave

text: -like and

text: particle

text: -like properties, the so-called

text: wave–particle duality

text: Runway edge lighting are used to outline the edges of runways during periods of darkness or restricted visibility conditions. These light systems are classified according to the intensity they are capable of producing:

text: Runway edge lighting are used to outline the edges of

text: runway

text: s during periods of darkness or restricted visibility conditions. These light systems are classified according to the

text: intensity

text: they are capable of producing:

text: Metamaterials were introduced about a decade ago, and these expand control of parts of the electromagnetic spectrum; from microwave, to terahertz, to infrared. Theoretically, metamaterials, as a transmission medium, will eventually expand control and direction of electromagnetic fields into the visible spectrum. Hence, a design strategy was introduced in 2006, to show that a metamaterial can be engineered with arbitrarily assigned positive or negative values of permittivity and permeability, which can also be independently varied at will. Then direct control of electromagnetic fields becomes possible, which is relevant to novel and unusual lens design, as well as a component of the scientific theory for cloaking of objects from electromagnetic detection.

text: Metamaterials

text: were introduced about a decade ago, and these expand control of parts of the

text: electromagnetic spectrum

text: ; from

text: microwave

text: , to

text: terahertz

text: , to

text: infrared

text: . Theoretically, metamaterials, as a

text: transmission medium

text: , will eventually expand control and direction of electromagnetic fields into the

text: visible spectrum

text: . Hence, a design strategy was introduced in 2006, to show that a metamaterial can be engineered with arbitrarily assigned positive or negative values of

text: permittivity

text: and

text: permeability

text: , which can also be independently varied at will. Then direct control of electromagnetic fields becomes possible, which is relevant to novel and unusual lens design, as well as a component of the

text: scientific theory

text: for cloaking of objects from electromagnetic detection.

text: Dark matter is a hypothetical kind of matter that is invisible to the entire electromagnetic spectrum, but which accounts for most of the matter in the Universe. The existence and properties of dark matter are inferred from its gravitational effects on visible matter, radiation, and the large-scale structure of the Universe. Other than neutrinos, a form of hot dark matter, dark matter has not been detected directly, making it one of the greatest mysteries in modern astrophysics. Dark matter neither emits nor absorbs light or any other electromagnetic radiation at any significant level. Dark matter is estimated to constitute 26.8% of the total mass–energy and 84.5%  of the total matter in the Universe.

text: Dark matter is a hypothetical kind of

text: matter

text: that is invisible to the entire

text: electromagnetic spectrum

text: , but which accounts for most of the matter in the Universe. The existence and properties of dark matter are inferred from its gravitational effects on visible matter, radiation, and the

text: large-scale structure

text: of the Universe. Other than

text: neutrinos

text: , a form of

text: hot dark matter

text: , dark matter has not been detected directly, making it one of the greatest mysteries in modern

text: astrophysics

text: . Dark matter neither

text: emits

text: nor absorbs light or any other

text: electromagnetic radiation

text: at any significant level. Dark matter is estimated to constitute 26.8% of the total mass–energy and 84.5%  of the total matter in the Universe.

text: The theme Light+HeART seeks to convey the message that “in the heart of the sustainability matters, is the matter of the heart”.  Through this edition, the festival hopes to create unique, happy and heart-felt installations to delight the audience while driving home the sustainability message.  This edition also saw a greater number of collaborations with the community and schools to form some of the art installations such as The Wishing! Tree and #WEHEARTLIGHT.

text: Orcus straddles the edge for trans-Neptunian objects massive enough to retain volatiles such as methane on the surface. The reflectance spectrum of Orcus shows the deepest water-ice absorption bands of any Kuiper belt object (KBO) that is not associated with the Haumea collisional family. The large icy satellites of Uranus have infrared spectra quite similar to that of Orcus. Among other trans-Neptunian objects Pluto's moon Charon appears to be most similar to Orcus. It has a higher albedo but very similar visible and near-infrared spectra. Their densities are also similar and both have water ice rich surfaces. Quaoar—a trans-Neptunian object of similar size—has strong water ice absorption features in its spectra but also has a very red color in the visible line implying the presence of ultrared matter on its surface. Dwarf planet Haumea and objects from its collisional family have much higher albedos and much deeper water absorption bands than Orcus. Finally, —another large object in 2:3 resonance with Neptune—has spectral properties very similar to Orcus.

text: Orcus straddles the edge for trans-Neptunian objects massive enough to retain volatiles such as methane on the surface. The reflectance spectrum of Orcus shows the deepest

text: water-ice absorption

text: bands of any Kuiper belt object (KBO) that is not associated with the

text: Haumea collisional family

text: . The

text: large icy satellites of Uranus

text: have infrared spectra quite similar to that of Orcus. Among other trans-Neptunian objects Pluto's moon

text: Charon

text: appears to be most similar to Orcus. It has a higher albedo but very similar visible and near-infrared spectra. Their densities are also similar and both have water ice rich surfaces.

text: Quaoar

text: —a trans-Neptunian object of similar size—has strong water ice absorption features in its spectra but also has a very red color in the visible line implying the presence of

text: ultrared matter

text: on its surface. Dwarf planet

text: Haumea

text: and objects from its collisional family have much higher albedos and much deeper water absorption bands than Orcus. Finally, —another large object in 2:3 resonance with Neptune—has spectral properties very similar to Orcus.

text: Current issued DPM equipment is IRR (Infrared Reflective) coated. This coating has a specific reflective wavelength in order to blend in with natural colours in the infra-red light spectrum. This reduces the visibility of soldiers to night vision devices, which detect infra-red light, as trees and other green plants reflect deep red and infra-red light (the Wood Effect).

text: Current issued DPM equipment is IRR (

text: Infrared

text: Reflective) coated. This coating has a specific reflective wavelength in order to blend in with natural colours in the infra-red

text: light spectrum

text: . This reduces the visibility of soldiers to

text: night vision device

text: s, which detect infra-red light, as trees and other green plants reflect deep red and infra-red light (the

text: Wood Effect

text: In visible light there is a strong absorption band termed ν near 710 nm which is caused by an electronic transition from T(F) → T(P).  Another strong absorption and is in the near infrared called ν near 770 nm due to T(F) → A(F).

text: Neon lighting is closely related to fluorescent lighting, which developed about 25 years after neon tube lighting. In fluorescent lights, the light emitted by rarefied gases within a tube is used exclusively to excite fluorescent materials that coat the tube, which then shine with their own colors that become the tube's visible, usually white, glow. Fluorescent coatings and glasses are also an option for neon tube lighting, but are usually selected to obtain bright colors.

text: Neon lighting is closely related to

text: fluorescent lighting

text: , which developed about 25 years after neon tube lighting. In fluorescent lights, the light emitted by rarefied gases within a tube is used exclusively to excite fluorescent materials that coat the tube, which then shine with their own colors that become the tube's visible, usually white, glow. Fluorescent coatings and glasses are also an option for neon tube lighting, but are usually selected to obtain bright colors.

text: of 2.93 which  extends their lifespan enough to travel 2.6 meters through the nozzle before decaying into muons. Sixty percent of the pions will have either a negative, or a positive electric charge. Forty percent of the pions will be neutral. The neutral pions will decay immediately into gamma rays. These can't be reflected by any known material at the energies involved, although they can undergo Compton scattering. They can be absorbed efficiently by a shield of tungsten placed between the pion rocket engine reaction volume and the crew modules and various electromagnets to protect them from the gamma rays. The consequent heating of the shield will cause it to radiate visible light, which could then be collimated to increase the rocket's specific impulse. The remaining heat will also require the shield to be refrigerated. The charged pions would travel in helical spirals around the axial electromagnetic field lines inside the nozzle and in this way the charged pions could be collimated into an exhaust jet that is moving at 0.94c. In realistic matter/antimatter reactions, this jet only represents a fraction of the reaction's mass-energy : over 60% of it is lost as gamma-rays, collimation is not perfect, and some pions are not reflected backwards by the nozzle. Thus, the effective exhaust velocity for the entire reaction drops to just 0.58c. Alternative propulsion schemes include physical confinement of hydrogen atoms in an antiproton and pion-transparent beryllium reaction chamber with collimation of the reaction products achieved with a single external electromagnet; see Project Valkyrie.

text: of 2.93 which  extends their lifespan enough to travel 2.6 meters through the nozzle before decaying into

text: muon

text: s. Sixty percent of the pions will have either a negative, or a positive electric charge. Forty percent of the pions will be neutral. The neutral pions will decay immediately into gamma rays. These can't be reflected by any known material at the energies involved, although they can undergo

text: Compton scattering

text: . They can be absorbed efficiently by a shield of

text: tungsten

text: placed between the pion rocket engine reaction volume and the crew modules and various electromagnets to protect them from the gamma rays. The consequent heating of the shield will cause it to radiate visible light, which could then be collimated to increase the rocket's specific impulse. The remaining heat will also require the shield to be refrigerated. The charged pions would travel in helical spirals around the axial electromagnetic field lines inside the nozzle and in this way the charged pions could be collimated into an exhaust jet that is moving at 0.94c. In realistic matter/antimatter reactions, this jet only represents a fraction of the reaction's mass-energy : over 60% of it is lost as

text: gamma-rays

text: , collimation is not perfect, and some pions are not reflected backwards by the nozzle. Thus, the effective exhaust velocity for the entire reaction drops to just 0.58c. Alternative propulsion schemes include physical confinement of hydrogen atoms in an antiproton and pion-transparent

text: beryllium

text: reaction chamber with collimation of the reaction products achieved with a single external electromagnet; see

text: Project Valkyrie

text: An electron microscope is a microscope that uses a beam of accelerated electrons as a source of illumination. As the wavelength of an electron can be up to 100,000 times shorter than that of visible light photons, electron microscopes have a higher resolving power than light microscopes and can reveal the structure of smaller objects. A transmission electron microscope can achieve better than 50 pm resolution and magnifications of up to about 10,000,000x whereas most light microscopes are limited by diffraction to about 200 nm resolution and useful magnifications below 2000x.

text: An electron microscope is a microscope that uses a beam of accelerated

text: electron

text: s as a source of illumination. As the wavelength of an electron can be up to 100,000 times shorter than that of visible light

text: photon

text: s, electron microscopes have a higher

text: resolving power

text: than

text: light microscope

text: s and can reveal the structure of smaller objects. A transmission electron microscope can achieve better than 50

text: pm

text: resolution and

text: magnification

text: s of up to about 10,000,000x whereas most

text: light microscope

text: s are limited by

text: diffraction

text: to about 200

text: nm

text: resolution and useful magnifications below 2000x.

text: The MCD signal ΔA is derived via the absorption of the LCP and RCP light as

text: Low-frequency radio waves travel easily through brick and stone and VLF even penetrates sea-water. As the frequency rises, absorption effects become more important. At microwave or higher frequencies, absorption by molecular resonances in the atmosphere (mostly from water, HO and oxygen, O) is a major factor in radio propagation. For example, in the 58–60 GHz band, there is a major absorption peak which makes this band useless for long-distance use. This phenomenon was first discovered during radar research in World War II. Above about 400 GHz, the Earth's atmosphere blocks most of the spectrum while still passing some - up to UV light, which is blocked by ozone - but visible light and some of the near-infrared is transmitted.Heavy rain and falling snow also affect microwave absorption.

text: Low-frequency radio waves travel easily through brick and stone and VLF even penetrates sea-water. As the frequency rises, absorption effects become more important. At

text: microwave

text: or higher frequencies, absorption by molecular resonances in the atmosphere (mostly from water, HO and oxygen, O) is a major factor in radio propagation. For example, in the 58–60 GHz band, there is a major absorption peak which makes this band useless for long-distance use. This phenomenon was first discovered during

text: radar

text: research in

text: World War II

text: . Above about 400 GHz, the Earth's atmosphere blocks most of the spectrum while still passing some - up to UV light, which is blocked by ozone - but visible light and some of the near-infrared is transmitted.Heavy rain and falling snow also affect microwave absorption.

text: is about 70°. In a dry objective or condenser, this gives a maximum NA of 0.95. In a high-resolution oil immersion lens, the maximum NA is typically 1.45, when using immersion oil with a refractive index of 1.52. Due to these limitations, the resolution limit of a light microscope using visible light is about 200 nm. Given that the shortest wavelength of visible light is violet (

text: is about 70°. In a dry objective or condenser, this gives a maximum NA of 0.95. In a high-resolution

text: oil immersion lens

text: , the maximum NA is typically 1.45, when using immersion oil with a refractive index of 1.52. Due to these limitations, the resolution limit of a light microscope using

text: visible light

text: is about 200

text: nm

text: . Given that the shortest wavelength of visible light is

text: violet

text: This is a list of reflected sources of light examples in contrast to the List of light sources. The list is oriented towards visible light reflection.

text: This is a list of reflected sources of light examples in contrast to the

text: List of light sources

text: . The list is oriented towards visible light reflection.

text: Forms of energy, such as light and heat, are not considered to be matter, and are thus not "substances" in this regard.

text: Forms of

text: energy

text: , such as

text: light

text: and

text: heat

text: , are not considered to be matter, and are thus not "substances" in this regard.

text: By following controller commands to keep the landing aircraft on both glidepath and approach centerline, a pilot will arrive precisely over the runway's touchdown zone. In order to insure continuous radio communication integrity, controllers are required to make radio transmissions at certain minimum intervals depending on the type of approach flow and phase of the approach. In order to land, pilots must have the runway or runway environment in sight prior to reaching the "decision height," for PAR approaches (usually 100–400 ft above the runway touchdown zone) or prior to the "Missed Approach Point" for non-precision approaches. The published minimum visibility and decision height/minimum descent altitude vary depending upon the approach and runway lighting, obstacles in the approach corridor, type of aircraft, and other factors. Pilots of revenue flights periodically must demonstrate PAR approach proficiency, and GCA controllers must conduct a minimum number of such approaches in a year to maintain competency.

text: Matter cannon as a ship-to-ship weapon in space is effective precisely because nothing can reasonably withstand the impact of mass traveling at light-constant speeds, even for a few picoseconds.  Matter traveling at the speed of light effectively has infinite momentum, and thus infinite mass; further, special relativity suggests that time dilation effects would increase the effective mass infinitely at the speed of light.  Therefore, several micrograms of hydrogen or neutron matter impacting the side of a ship at the speed of light would have the same impact as several hundred billion teragrams and more of neutron star matter impacting the side of the ship at near-light speeds.

text: Matter cannon as a ship-to-ship weapon in space is effective precisely because nothing can reasonably withstand the impact of

text: mass

text: traveling at light-constant speeds, even for a few picoseconds.  Matter traveling at the speed of light effectively has infinite momentum, and thus infinite mass; further,

text: special relativity

text: suggests that

text: time dilation

text: effects would increase the effective mass infinitely at the speed of light.  Therefore, several micrograms of hydrogen or neutron matter impacting the side of a ship at the speed of light would have the same impact as several hundred billion teragrams and more of

text: neutron star

text: matter impacting the side of the ship at near-light speeds.

text: The phase velocity is important in determining how a light wave travels through a material or from one material to another. It is often represented in terms of a refractive index. The refractive index of a material is defined as the ratio of c to the phase velocity v in the material: larger indices of refraction indicate lower speeds. The refractive index of a material may depend on the light's frequency, intensity, polarization, or direction of propagation; in many cases, though, it can be treated as a material-dependent constant. The refractive index of air is approximately 1.0003. Denser media, such as water, glass, and diamond, have refractive indexes of around 1.3, 1.5 and 2.4, respectively, for visible light. In exotic materials like Bose–Einstein condensates near absolute zero, the effective speed of light may be only a few metres per second. However, this represents absorption and re-radiation delay between atoms, as do all slower-than-c speeds in material substances. As an extreme example of light "slowing" in matter, two independent teams of physicists claimed to bring light to a "complete standstill" by passing it through a Bose–Einstein condensate of the element rubidium, one team at Harvard University and the Rowland Institute for Science in Cambridge, Mass., and the other at the Harvard–Smithsonian Center for Astrophysics, also in Cambridge. However, the popular description of light being "stopped" in these experiments refers only to light being stored in the excited states of atoms, then re-emitted at an arbitrarily later time, as stimulated by a second laser pulse. During the time it had "stopped," it had ceased to be light. This type of behaviour is generally microscopically true of all transparent media which "slow" the speed of light.

text: The phase velocity is important in determining how a light wave travels through a material or from one material to another. It is often represented in terms of a refractive index. The refractive index of a material is defined as the ratio of c to the phase velocity v in the material: larger indices of refraction indicate lower speeds. The refractive index of a material may depend on the light's frequency, intensity,

text: polarization

text: , or direction of propagation; in many cases, though, it can be treated as a material-dependent constant. The

text: refractive index of air

text: is approximately 1.0003. Denser media, such as

text: water

text: , glass, and

text: diamond

text: , have refractive indexes of around 1.3, 1.5 and 2.4, respectively, for visible light. In exotic materials like

text: Bose–Einstein condensate

text: s near absolute zero, the effective speed of light may be only a few metres per second. However, this represents absorption and re-radiation delay between atoms, as do all slower-than-c speeds in material substances. As an extreme example of light "slowing" in matter, two independent teams of physicists claimed to bring light to a "complete standstill" by passing it through a Bose–Einstein condensate of the element

text: rubidium

text: , one team at

text: Harvard University

text: and the

text: Rowland Institute for Science

text: in Cambridge, Mass., and the other at the

entity_name: Harvard–Smithsonian Center for Astrophysics

text: Harvard–Smithsonian Center for Astrophysics

text: , also in Cambridge. However, the popular description of light being "stopped" in these experiments refers only to light being stored in the excited states of atoms, then re-emitted at an arbitrarily later time, as stimulated by a second laser pulse. During the time it had "stopped," it had ceased to be light. This type of behaviour is generally microscopically true of all transparent media which "slow" the speed of light.

text: Type II diamonds have no measurable nitrogen impurities. Type II diamonds absorb in a different region of the infrared, and transmit in the ultraviolet below , unlike Type I diamonds. They also have differing fluorescence characteristics, but no discernible visible absorption spectrum. Type IIa diamond can be colored pink, red, or brown due to structural anomalies  arising through plastic deformation during crystal growth—these diamonds are rare (1.8% of gem diamonds), but constitute a large percentage of Australian production. Type IIb diamonds, which account for 0.1% of gem diamonds, are usually light blue due to scattered boron within the crystal matrix; these diamonds are also semiconductors, unlike other diamond types (see Electrical properties of diamond). However, a blue-grey color may also occur in Type Ia diamonds and be unrelated to boron. Also not restricted to type are green diamonds, whose color is caused by GR1 color centers in the crystal lattice produced by exposure to varying quantities of radiation.

text: Type II diamonds have no measurable nitrogen impurities. Type II diamonds absorb in a different region of the infrared, and transmit in the ultraviolet below , unlike Type I diamonds. They also have differing fluorescence characteristics, but no discernible visible absorption spectrum. Type IIa diamond can be colored pink, red, or brown due to structural anomalies  arising through

text: plastic deformation

text: during crystal growth—these diamonds are rare (1.8% of gem diamonds), but constitute a large percentage of Australian production. Type IIb diamonds, which account for 0.1% of gem diamonds, are usually light blue due to scattered

text: boron

text: within the crystal matrix; these diamonds are also

text: semiconductor

text: s, unlike other diamond types (see

text: Electrical properties of diamond

text: ). However, a blue-grey color may also occur in Type Ia diamonds and be unrelated to boron. Also not restricted to type are green diamonds, whose color is caused by GR1

text: color centers

text: in the crystal lattice produced by exposure to varying quantities of

text: radiation

text: As GD 165B is the prototype of the L dwarfs, Gliese 229B is the prototype of a second new spectral class, the T dwarfs. Whereas near-infrared (NIR) spectra of L dwarfs show strong absorption bands of HO and carbon monoxide (CO), the NIR spectrum of Gliese 229B is dominated by absorption bands from methane (CH), features that were only found in the giant planets of the Solar System and Titan. CH, HO, and molecular hydrogen (H) collision-induced absorption (CIA) give Gliese 229B blue near-infrared colors. Its steeply sloped red optical spectrum also lacks the FeH and CrH bands that characterize L dwarfs and instead is influenced by exceptionally broad absorption features from the alkali metals Na and K. These differences led Kirkpatrick to propose the T spectral class for objects exhibiting H- and K-band CH absorption. , 355 T dwarfs are known. NIR classification schemes for T dwarfs have recently been developed by Adam Burgasser and Tom Geballe. Theory suggests that L dwarfs are a mixture of very-low-mass stars and sub-stellar objects (brown dwarfs), whereas the T dwarf class is composed entirely of brown dwarfs. Because of the absorption of sodium and potassium in the green part of the spectrum of T dwarfs, the actual appearance of T dwarfs to human visual perception is estimated to be not brown, but the color of magenta coal tar dye. T-class brown dwarfs, such as WISE 0316+4307, have been detected over 100 light-years from the Sun.

text: As GD 165B is the prototype of the L dwarfs,

text: Gliese 229

text: B is the prototype of a second new spectral class, the T dwarfs. Whereas

text: near-infrared

text: (NIR) spectra of L dwarfs show strong absorption bands of HO and

text: carbon monoxide

text: (CO), the NIR spectrum of Gliese 229B is dominated by absorption bands from

text: methane

text: (CH), features that were only found in the giant planets of the Solar System and

text: Titan

text: . CH, HO, and molecular

text: hydrogen

text: (H) collision-induced absorption (CIA) give Gliese 229B blue near-infrared colors. Its steeply sloped red optical spectrum also lacks the FeH and CrH bands that characterize L dwarfs and instead is influenced by exceptionally broad absorption features from the

text: alkali

text: metals

text: and

text: K

text: . These differences led Kirkpatrick to propose the T spectral class for objects exhibiting H- and K-band CH absorption. , 355 T dwarfs are known. NIR classification schemes for T dwarfs have recently been developed by Adam Burgasser and Tom Geballe. Theory suggests that L dwarfs are a mixture of very-low-mass stars and sub-stellar objects (brown dwarfs), whereas the T dwarf class is composed entirely of brown dwarfs. Because of the absorption of

text: sodium

text: and

text: potassium

text: in the green part of the spectrum of T dwarfs, the actual appearance of T dwarfs to human

text: visual perception

text: is estimated to be not brown, but the color of

text: magenta coal tar dye

text: . T-class brown dwarfs, such as

text: WISE 0316+4307

text: , have been detected over 100 light-years from the Sun.

text: A core feature of absorption is an experience of focused attention wherein: "objects of absorbed attention acquire an importance and intimacy that are normally reserved for the self and may, therefore, acquire a temporary self-like quality. These object identifications have mystical overtones." This capacity for focused attention facilitates the experience of altered states of consciousness. In addition to individual differences in hypnotizability, absorption is associated with differential responses to other procedures for inducing altered states of consciousness, including meditation, marijuana use, and biofeedback. A review of studies on differential response to the drug psilocybin found that absorption had the largest effect of all the psychological variables assessed on the intensity of individual experiences of altered states of consciousness. Absorption was strongly associated with overall consciousness alteration and with mystical-type experiences and visual effects induced by psilocybin. Researchers have suggested that individual differences in both absorption and responsiveness to hallucinogenic drugs could be related to the binding potential of serotonin receptors (specifically 5-HT) which are the main site of action of classic hallucinogens, such as LSD and psilocybin.

text: A core feature of absorption is an experience of focused attention wherein: "objects of absorbed attention acquire an importance and intimacy that are normally reserved for the self and may, therefore, acquire a temporary self-like quality. These object identifications have mystical overtones." This capacity for focused attention facilitates the experience of altered states of consciousness. In addition to individual differences in hypnotizability, absorption is associated with differential responses to other procedures for inducing altered states of consciousness, including

text: meditation

text: marijuana

text: use, and

text: biofeedback

text: . A review of studies on differential response to the drug

text: psilocybin

text: found that absorption had the largest effect of all the psychological variables assessed on the intensity of individual experiences of altered states of consciousness. Absorption was strongly associated with overall consciousness alteration and with mystical-type experiences and visual effects induced by psilocybin. Researchers have suggested that individual differences in both absorption and responsiveness to hallucinogenic drugs could be related to the binding potential of

text: serotonin

text: receptors (specifically

text: ) which are the main site of action of classic hallucinogens, such as

text: LSD

text: and psilocybin.

text: The phaneron (Greek φανερός [phaneros] "visible, manifest") is the subject matter of phenomenology, or of what Charles Sanders Peirce later called phaneroscopy.

text: The phaneron (Greek φανερός [phaneros] "visible, manifest") is the subject matter of

text: phenomenology

text: , or of what

text: Charles Sanders Peirce

text: later called phaneroscopy.

text: To a conventionally composed Roman glass flux 330 parts per million of silver and 40 of gold were added: "These particles were precipitated as colloids and form a silver-gold alloy.  When viewed in reflected light the minute metallic particles are just coarse enough to reflect enough of the light without eliminating the transmission.  In transmitted light the fine particles scatter the blue end of the spectrum more effectively than the red end, resulting in red transmission, and this is the colour observed.  Since it is impossible that the Roman artisans managed to add these incredibly low levels of silver and gold to the volume of the glass used to make the vessel deliberately, the levels were probably added at higher levels to a larger volume of glass-melt, and increasingly diluted by adding more glass."  The particles are only about 70 nanometers across, and embedded in the glass, so they cannot be seen by optical microscopy, and a transmission electron microscope is needed instead.  At this size they approach the size of the wavelengths of visible light, and a surface plasmon resonance effect takes place.

text: To a conventionally composed Roman glass flux 330 parts per million of silver and 40 of gold were added: "These particles were precipitated as colloids and form a silver-gold alloy.  When viewed in reflected light the minute metallic particles are just coarse enough to reflect enough of the light without eliminating the transmission.  In transmitted light the fine particles scatter the blue end of the spectrum more effectively than the red end, resulting in red transmission, and this is the colour observed.  Since it is impossible that the Roman artisans managed to add these incredibly low levels of silver and gold to the volume of the glass used to make the vessel deliberately, the levels were probably added at higher levels to a larger volume of glass-melt, and increasingly diluted by adding more glass."  The particles are only about 70

text: nanometer

text: s across, and embedded in the glass, so they cannot be seen by optical microscopy, and a

text: transmission electron microscope

text: is needed instead.  At this size they approach the size of the wavelengths of visible light, and a

text: surface plasmon resonance

text: effect takes place.

text: The wavelengths at which azobenzene isomerization occurs depends on the particular structure of each azo molecule, but they are typically grouped into three classes: the azobenzene-type molecules, the aminoazobenzenes, and the pseudo-stilbenes. These azos are yellow, orange, and red, respectively, owing to the subtle differences in their electronic absorption spectra. The compounds similar to the unsubstituted azobenzene exhibit a low-intensity n-π* absorption in the visible region, and a much higher intensity π-π* absorption in the ultraviolet. Azos that are ortho- or para-substituted with electron-donating groups (such as aminos), are classified as aminoazobenzenes, and tend to closely spaced n-π* and π-π* bands in the visible. The pseudo-stilbene class is characterized by substituting the 4 and 4' positions of the two azo rings with electron-donating and electron-withdrawing groups (that is, the two opposite ends of the aromatic system are functionalized). The addition of this push-pull configuration results in a strongly asymmetric electron distribution, which modifies a host of optical properties. In particular, it shifts the absorption spectra of the trans and the cis isomers, so that they effectively overlap. Thus, for these compounds a single wavelength of light in the visible region will induce both the forward and reverse isomerization. Under illumination, these molecules cycle between the two isomeric states.

text: The wavelengths at which azobenzene isomerization occurs depends on the particular structure of each azo molecule, but they are typically grouped into three classes: the azobenzene-type molecules, the aminoazobenzenes, and the pseudo-

text: stilbenes

text: . These azos are yellow, orange, and red, respectively, owing to the subtle differences in their electronic absorption spectra. The compounds similar to the unsubstituted azobenzene exhibit a low-intensity n-π* absorption in the visible region, and a much higher intensity π-π* absorption in the

text: ultraviolet

text: . Azos that are

text: ortho-

text: or

text: para-

text: substituted with

text: electron-donating group

text: s (such as

text: amino

text: s), are classified as aminoazobenzenes, and tend to closely spaced n-π* and π-π* bands in the visible. The pseudo-stilbene class is characterized by substituting the 4 and 4' positions of the two azo rings with electron-donating and electron-withdrawing groups (that is, the two opposite ends of the

text: aromatic

text: system are functionalized). The addition of this

text: push-pull

text: configuration results in a strongly asymmetric

text: electron

text: distribution, which modifies a host of optical properties. In particular, it shifts the

text: absorption spectra

text: of the trans and the cis isomers, so that they effectively overlap. Thus, for these compounds a single

text: wavelength

text: of light in the visible region will induce both the forward and reverse isomerization. Under illumination, these molecules cycle between the two isomeric states.

text: Calorescence is when matter absorbs infrared radiant energy and emits visible radiant energy in its place. For example, some kinds of flammable gas give off large amounts of radiant heat and very little visible light when burning, and if a piece of metal is placed into such a flame, the metal will become bright red-hot—which is to say the metal absorbs invisible infrared and emits visible radiation. The word calorescence was coined in 1864 on the model of the word fluorescence which had been coined in 1852. At that time, fluorescence was defined as absorption in the ultraviolet part of the spectrum followed by emission in the visible part of the spectrum. Calorescence was defined complementarily as absorption in the infrared followed by emission in the visible.

text: Calorescence is when matter absorbs

text: infrared

text: radiant energy and emits

text: visible

text: radiant energy in its place. For example, some kinds of flammable gas give off large amounts of radiant heat and very little visible light when burning, and if a piece of metal is placed into such a flame, the metal will become bright red-hot—which is to say the metal absorbs invisible infrared and emits visible radiation. The word calorescence was coined in 1864 on the model of the word

text: fluorescence

text: which had been coined in 1852. At that time, fluorescence was defined as absorption in the ultraviolet part of the spectrum followed by emission in the visible part of the spectrum. Calorescence was defined complementarily as absorption in the infrared followed by emission in the visible.

text: The Big Bang theory is the prevailing cosmological model for the universe from the earliest known periods through its subsequent large-scale evolution. The model accounts for the fact that the universe expanded from a very high density and high temperature state, and offers a comprehensive explanation for a broad range of phenomena, including the abundance of light elements, the cosmic microwave background, large scale structure and Hubble's Law. If the known laws of physics are extrapolated to the highest density regime, the result is a singularity which is typically associated with the Big Bang. Detailed measurements of the expansion rate of the universe place this moment at approximately 13.8 billion years ago, which is thus considered the age of the universe. After the initial expansion, the universe cooled sufficiently to allow the formation of subatomic particles, and later simple atoms. Giant clouds of these primordial elements later coalesced through gravity in halos of dark matter, eventually forming the stars and galaxies visible today.

text: The Big Bang

text: theory

text: is the prevailing

text: cosmological

text: model

text: for the

text: universe

text: from the

text: earliest known periods

text: through its subsequent large-scale evolution. The model accounts for the fact that the universe

text: expanded

text: from a very high density and high temperature state, and offers a comprehensive explanation for a broad range of phenomena, including the abundance of

text: light element

text: s, the

text: cosmic microwave background

text: large scale structure

text: and

text: Hubble's Law

text: . If the known laws of physics are extrapolated to the highest density regime, the result is a

text: singularity

text: which is typically associated with the Big Bang. Detailed measurements of the expansion rate of the universe place this moment at approximately 13.8

text: billion

text: years ago, which is thus considered the

text: age of the universe

text: . After the initial expansion, the universe cooled sufficiently to allow the formation of

text: subatomic particle

text: s, and later simple

text: atom

text: s. Giant clouds of these primordial elements later coalesced through

text: gravity

text: in halos of

text: dark matter

text: , eventually forming the

text: star

text: s and

text: galaxies

text: visible today.

text: Electric transmission has been available as an alternative to conventional mechanical transmissions since 1903. Typically mechanical transmissions impose many penalties, including weight, bulk, noise, cost, complexity and a drain on engine power with every gear-change, whether accomplished manually or automatically. Unlike ICEs, electric motors do not require a transmission.

text: Electric transmission

text: has been available as an alternative to conventional mechanical transmissions since 1903. Typically mechanical transmissions impose many penalties, including weight, bulk, noise, cost, complexity and a drain on engine power with every gear-change, whether accomplished manually or automatically. Unlike ICEs, electric motors do not require a transmission.

text: Baryonic matter is the part of the universe that is made of baryons (including all atoms). This part of the universe does not include dark energy, dark matter, black holes or various forms of degenerate matter, such as compose white dwarf stars and neutron stars. Microwave light seen by Wilkinson Microwave Anisotropy Probe (WMAP), suggests that only about 4.6% of that part of the universe within range of the best telescopes (that is, matter that may be visible because light could reach us from it), is made of baryonic matter. About 23% is dark matter, and about 72% is dark energy.

text: Baryonic matter is the part of the universe that is made of baryons (including all atoms). This part of the universe does not include

text: dark energy

text: dark matter

text: black holes

text: or various forms of degenerate matter, such as compose

text: white dwarf

text: stars and

text: neutron star

text: s. Microwave light seen by

text: Wilkinson Microwave Anisotropy Probe

text: (WMAP), suggests that only about 4.6% of that part of the universe within range of the best

text: telescope

text: s (that is, matter that may be visible because light could reach us from it), is made of baryonic matter. About 23% is dark matter, and about 72% is dark energy.

text: Manual transmission is also known as a manual gearbox, stick shift, standard, and stick. Most automobile manual transmissions have several gear ratios that are chosen by locking selected gear pairs to the output shaft inside the transmission. Manual transmissions feature a driver-operated clutch and gear stick. Historically, cars had a manual overdrive switch.

text: Manual transmission is also known as a manual gearbox, stick shift, standard, and stick. Most automobile manual transmissions have several

text: gear ratio

text: s that are chosen by locking selected gear pairs to the output shaft inside the transmission. Manual transmissions feature a driver-operated clutch and

text: gear stick

text: . Historically, cars had a manual

text: overdrive

text: switch.

text: Isherwood also notes that this serves a female audience. "If there are chick flicks and chick lit – derogatory though some might find those terms to be – Love, Loss, and What I Wore should clearly be classified as chick legit...for the women who can share deeply in the particulars of experience dissected and discussed." The Los Angeles Times notes the light nature of the subject matter: "...isn't out to reclaim female sexuality from centuries of oppression; it wittily celebrates wardrobe malfunctions..." According to Reiner, the show points out that "...if there is one thing the females of the species have in common, it's a deep and abiding love/hate relationship with their wardrobe...this wonderfully witty show illustrates, what one wears to the party is sometimes more memorable than the party itself." He also notes that the entire performance has meaning as it is "jam-packed and resonant" throughout. Shaw notes that "The cozy humor strikes many women's funny bones with a mighty whack, perhaps because it reaffirms so perfectly their own preoccupations."

text: In 2014, experimentalists proposed a way to validate an idea by Breit and John A. Wheeler that matter formation by could be achieved by interacting light particles ("Breit–Wheeler process").

text: In 2014, experimentalists proposed a way to validate an idea by Breit and

text: John A. Wheeler

text: that matter formation by could be achieved by interacting light particles ("

text: Breit–Wheeler process

text: Because normal paddling involves alternately dipping and raising the paddle blades, the colour of the blades may affect the visibility of the kayaker to powerboats operators under limited visibility conditions. For this reason white or yellow blades may offer a safety advantage over black or blue blades. Of course, kayakers should wear a headlamp or have other lighting on their kayak under conditions of limited lighting. However, if a powerboat operator must look straight into a sun low in the sky to see a kayaker, the motion of brightly coloured paddle blades may be of more value than lighting on the kayak. Highly reflective water resistant tape (e.g. SOLAS tape) may be affixed to the paddle blades and boat to enhance visibility.

text: Because normal paddling involves alternately dipping and raising the paddle blades, the colour of the blades may affect the visibility of the kayaker to powerboats operators under limited visibility conditions. For this reason white or yellow blades may offer a safety advantage over black or blue blades. Of course, kayakers should wear a headlamp or have other lighting on their kayak under conditions of limited lighting. However, if a powerboat operator must look straight into a sun low in the sky to see a kayaker, the motion of brightly coloured paddle blades may be of more value than lighting on the kayak. Highly reflective water resistant tape (e.g.

text: SOLAS

text: tape) may be affixed to the paddle blades and boat to enhance visibility.

text: In chemistry, absorption is a physical or chemical phenomenon or a process in which atoms, molecules or ions enter some bulk phase – gas, liquid or solid material. This is a different process from adsorption, since molecules undergoing absorption are taken up by the volume, not by the surface (as in the case for adsorption). A more general term is sorption, which covers absorption, adsorption, and ion exchange. Absorption is a condition in which something takes in another substance.

text: In

text: chemistry

text: , absorption is a physical or chemical

text: phenomenon

text: or a

text: process

text: in which

text: atom

text: s,

text: molecules

text: or

text: ion

text: s enter some bulk phase –

text: gas

text: liquid

text: or

text: solid

text: material. This is a different process from

text: adsorption

text: , since molecules undergoing absorption are taken up by the volume, not by the surface (as in the case for adsorption). A more general term is

text: sorption

text: , which covers absorption,

text: adsorption

text: , and

text: ion exchange

text: . Absorption is a condition in which something takes in another substance.

text: The object is a blazar, in fact an FSRQ (Flat Spectrum Radio Quasar) quasar, the most energetic subclass of objects known as active galactic nuclei, produced by the rapid accretion of matter by a central supermassive black hole, changing the gravitational energy to light energy that can be visible in cosmic distances. In the case of S5 0014+81 it is one of the most luminous quasars known, with a total luminosity of over 10 watts, equal to an absolute bolometric magnitude of -31.5. If the quasar were at a distance of 280 light-years from Earth, it would give as much energy per square meter as the Sun despite being 18 million times more distant. The quasar's luminosity is therefore about 3 x 10 (300 trillion) times the Sun, or over 25,000 times as luminous as all the 100 to 400 billion stars of the Milky Way Galaxy combined, making it one of the most powerful objects in the universe. However, because of its huge distance of 12.1 billion light-years it can only be studied by spectroscopy. The central black hole of the quasar devours an extremely huge amount of matter, equivalent to 4,000 solar masses of material every year.

text: The object is a

text: blazar

text: , in fact an FSRQ (Flat Spectrum Radio Quasar)

text: quasar

text: , the most energetic subclass of objects known as

text: active galactic nuclei

text: , produced by the rapid accretion of matter by a central

text: supermassive black hole

text: , changing the gravitational energy to light energy that can be visible in cosmic distances. In the case of S5 0014+81 it is one of the most luminous quasars known, with a total luminosity of over 10

text: watt

text: s, equal to an

text: absolute bolometric magnitude

text: of -31.5. If the quasar were at a distance of 280 light-years from Earth, it would give as much energy per square meter as the Sun despite being 18 million times more distant. The quasar's luminosity is therefore about 3 x 10 (300 trillion) times the

text: Sun

text: , or over 25,000 times as luminous as all the 100 to 400 billion stars of the

text: Milky Way

text: Galaxy combined, making it one of the most powerful objects in the universe. However, because of its huge distance of 12.1 billion light-years it can only be studied by

text: spectroscopy

text: . The central black hole of the quasar devours an extremely huge amount of matter, equivalent to 4,000 solar masses of material every year.

text: Light transmission (for this article, the perceivable visible spectrum between 390 nm and 750 nm is considered) through glass is diminished either by light reflection or light absorption of the glazing material. The total light transferred through the glazing material (light transmission) is reduced by reflection and/or absorption. In art framing, light reflection causes glare, while light absorption also may cause the transmitted colors to be dulled or distorted. While type of the glass substrate will affect the light absorption of the glazing, the surface treatment can affect light scattering, light reflection and in some cases, light absorption. There are various glazing options to achieve this goal as explained in the following sections on Types of Picture Framing Glass.

text: Light transmission

text: (for this article, the perceivable

text: visible spectrum

text: between 390 nm and 750 nm is considered) through glass is diminished either by

text: light reflection

text: or

text: light absorption

text: of the glazing material. The total light transferred through the glazing material (light transmission) is reduced by reflection and/or absorption. In art framing,

text: light reflection

text: causes

text: glare

text: , while

text: light absorption

text: also may cause the transmitted colors to be dulled or distorted. While type of the glass substrate will affect the

text: light absorption

text: of the glazing, the surface treatment can affect

text: light scattering

text: light reflection

text: and in some cases,

text: light absorption

text: . There are various glazing options to achieve this goal as explained in the following sections on Types of Picture Framing Glass.

text: Evidence suggests that the X-rays may be associated with the Be star itself or caused by some complex interaction between the star and surrounding decretion disk. One line of evidence is that the X-ray production is known to vary on both short and long time scales with respect to various UV line and continuum changes associated with a B star or with circumstellar matter close to the star. Moreover, the X-ray emissions exhibit long-term cycles that correlate with the light curves in the visible wavelengths.

text: Total external reflection is an optical phenomenon where electromagnetic radiation (e.g. visible light) can, at certain angles,  be totally reflected from an interface between two media of different indices of refraction (see Snell's law).  Total internal reflection occurs when the first medium has a larger refractive index than the second medium, for example,  light that emerges from under water. The optically denser material (water in this case) is the "internal" medium. For visible light, water has an index of refraction of 1.33 and for air it is very close to 1. For vacuum the index of refraction is exactly 1 for all wavelengths.

text: Total external reflection is an optical phenomenon where electromagnetic radiation (e.g. visible light) can, at certain angles,  be totally reflected from an interface between two media of different indices of refraction (see

text: Snell's law

text: Total internal reflection

text: occurs when the first medium has a larger

text: refractive index

text: than the second medium, for example,  light that emerges from under water. The optically denser material (water in this case) is the "internal" medium. For visible light, water has an index of refraction of 1.33 and for air it is very close to 1. For vacuum the index of refraction is exactly 1 for all wavelengths.

text: Different types and grades of glass and different window treatments can also affect the amount of light transmission through the windows. The type of glazing is an important issue, expressed by its VT coefficient (Visual Transmittance), also known as visual light transmittance (VLT). As the name suggests, this coefficient measures how much visible light is admitted by the window. A low VT (below 0.4) can reduce by half or more the light coming into a room. But be also aware of high VT glass: high VT numbers (say, above 0.60) can be a cause of glare. On the other hand, you should also take into account the undesirable effects of large windows.

text: Absorption is most commonly measured by the Tellegen Absorption Scale (TAS). Several versions of this scale are available, the most recent being by Graham Jamieson, who provides a copy of his modified scale. The TAS comprises nine content clusters or subscales:

text: When sunlight encounters a raindrop, part of the light is reflected and the rest enters the raindrop. The light is refracted at the surface of the raindrop. When this light hits the back of the raindrop, some of it is reflected off the back. When the internally reflected light reaches the surface again, once more some is internally reflected and some is refracted as it exits the drop. (The light that reflects off the drop, exits from the back, or continues to bounce around inside the drop after the second encounter with the surface, is not relevant to the formation of the primary rainbow.) The overall effect is that part of the incoming light is reflected back over the range of 0° to 42°, with the most intense light at 42°. This angle is independent of the size of the drop, but does depend on its refractive index. Seawater has a higher refractive index than rain water, so the radius of a "rainbow" in sea spray is smaller than a true rainbow. This is visible to the naked eye by a misalignment of these bows.

text: When sunlight encounters a raindrop, part of the light is reflected and the rest enters the raindrop. The light is

text: refracted

text: at the surface of the raindrop. When this light hits the back of the raindrop, some of it is reflected off the back. When the internally reflected light reaches the surface again, once more some is internally reflected and some is refracted as it exits the drop. (The light that reflects off the drop, exits from the back, or continues to bounce around inside the drop after the second encounter with the surface, is not relevant to the formation of the primary rainbow.) The overall effect is that part of the incoming light is reflected back over the range of 0° to 42°, with the most intense light at 42°. This angle is independent of the size of the drop, but does depend on its

text: refractive index

text: . Seawater has a higher refractive index than rain water, so the radius of a "rainbow" in sea spray is smaller than a true rainbow. This is visible to the naked eye by a misalignment of these bows.

text: Most existing X-ray telescopes use CCD detectors, similar to those in visible-light cameras. In visible-light, a single photon can produce a single electron of charge in a pixel, and an image is built up by accumulating many such charges from many photons during the exposure time. When an X-ray photon hits a CCD, it produces enough charge (hundreds to thousands of electrons, proportional to its energy) that the individual X-rays have their energies measured on read-out.

text: Most existing X-ray telescopes use

text: CCD

text: detectors, similar to those in visible-light cameras. In visible-light, a single photon can produce a single electron of charge in a pixel, and an image is built up by accumulating many such charges from many photons during the exposure time. When an X-ray photon hits a CCD, it produces enough charge (hundreds to thousands of electrons, proportional to its energy) that the individual X-rays have their energies measured on read-out.

text: Since objects can be seen by light in the visible spectrum from a source reflecting off their surfaces and hitting the viewer's eye, the most natural form of invisibility (whether real or fictional) is an object that neither reflects nor absorbs light (that is, it allows light to pass through it). This is known as transparency, and is seen in many naturally occurring materials (although no naturally occurring material is 100% transparent).

text: Since objects can be seen by light in the

text: visible spectrum

text: from a source reflecting off their surfaces and hitting the viewer's

text: eye

text: , the most natural form of invisibility (whether real or fictional) is an object that neither reflects nor absorbs light (that is, it allows light to pass through it). This is known as

text: transparency

text: , and is seen in many naturally occurring materials (although no naturally occurring material is 100% transparent).

text: The Bolshoi simulation follows the evolving distribution of a statistical ensemble of 8.6 billion particles of dark matter, each of which represents about 200 million solar masses, in a cube of 3-dimensional space about 1 billion light years on edge. Dark matter and dark energy dominate the evolution of the cosmos in this model. The dynamics are modeled with the ΛCDM theory and Einstein's general theory of relativity, with the model including cold dark matter (CDM) and the Λ cosmological constant term simulating the cosmic acceleration referred to as dark energy.

text: The Bolshoi simulation follows the evolving distribution of a statistical ensemble of 8.6 billion particles of

text: dark matter

text: , each of which represents about 200 million

text: solar mass

text: es, in a cube of 3-dimensional space about 1 billion light years on edge. Dark matter and

text: dark energy

text: dominate the evolution of the cosmos in this model. The dynamics are modeled with the ΛCDM theory and

text: Einstein

text: 's

text: general theory of relativity

text: , with the model including

text: cold dark matter

text: (CDM) and the Λ

text: cosmological constant

text: term simulating the

text: cosmic acceleration

text: referred to as dark energy.

text: While there is some correlation between the percentages of visible light and UV that pass through the same fabric, it is not a strong relationship. With new-technology textiles designed for the sole purpose of UV blocking, it is not always possible to judge the UV protection level simply by holding up the fabric and examining how much visible light passes through.

text: While there is some correlation between the percentages of

text: visible light

text: and UV that pass through the same fabric, it is not a strong relationship. With new-technology textiles designed for the sole purpose of UV blocking, it is not always possible to judge the UV protection level simply by holding up the fabric and examining how much visible light passes through.

text: When AuNP are exposed to NIR light, the oscillating electromagnetic field of the light causes the free electrons of the AuNP to collectively coherently oscillate. Changing the size and shape of AuNP, changes the wavelength that gets absorbed. A desired wavelength would be between 700-1000 nm because biological tissue is optically transparent at these wavelengths. While all AuNP properties are sensitive to change in their shape and size, Au nanorods properties are extremely sensitive to any change in any of their dimensions regarding their length and wide or their aspect ratio. When light is shown on a metal NP, the NP forms a dipole oscillation along the direction of the electric field. When the oscillation reaches its maximum, this frequency is called the surface plasmon resonance (SPR). AuNR have two SPR spectrum bands: one in the NIR region caused by its longitudinal oscillation which tends to be stronger with a longer wavelength and one in the visible region caused by the transverse electronic oscillation which tends to be weaker with a shorter wavelength. The SPR characteristics account for the increase in light absorption for the particle. As the AuNR aspect ratio increases, the absorption wavelength is redshifted and light scattering efficiency is increased.  The electrons excited by the NIR lose energy quickly after absorption via electron-electron collisions, and as these electrons relax back down, the energy is released as a phonon that then heats the environment of the AuNP which in cancer treatments would be the cancerous cells. This process is observed when a laser has a continuous wave onto the AuNP. Pulsed laser light beams generally results in the AuNP melting or ablation of the particle. Continues wave lasers take minutes rather than a single pulse time for a pulsed laser, continues wave lasers are able to heat larger areas at once.

text: Living organisms, for their part, can collectively affect weather patterns. The rate of evapotranspiration of forests, or of any large vegetated area for that matter, contributes to the release of water vapor in the atmosphere. This local, relatively fast and continuous process may contribute significantly to the persistence of precipitations in a given area. As another example, the wilting of plants results in definite changes in leaf angle distribution and therefore modifies the rates of reflection, transmission and absorption of solar light in these plants. That, in turn, changes the albedo of the ecosystem as well as the relative importance of the sensible and latent heat fluxes from the surface to the atmosphere. For an example in oceanography, consider the release of dimethyl sulfide by biological activity in sea water and its impact on atmospheric aerosols.

text: Living organisms, for their part, can collectively affect weather patterns. The rate of

text: evapotranspiration

text: of forests, or of any large vegetated area for that matter, contributes to the release of

text: water vapor

text: in the atmosphere. This local, relatively fast and continuous process may contribute significantly to the persistence of

text: precipitation

text: s in a given area. As another example, the

text: wilting

text: of plants results in definite changes in

text: leaf angle distribution

text: and therefore modifies the rates of

text: reflection

text: transmission

text: and

text: absorption

text: of solar light in these plants. That, in turn, changes the

text: albedo

text: of the ecosystem as well as the relative importance of the

text: sensible

text: and

text: latent heat

text: fluxes from the surface to the atmosphere. For an example in

text: oceanography

text: , consider the release of

text: dimethyl sulfide

text: by biological activity in sea water and its impact on atmospheric

text: aerosol

text: s.

text: One of them was developed by Fresnel (and subsequently Lorentz). This model (Stationary Aether Theory) supposed that light propagates as a transverse wave and aether is partially dragged with a certain coefficient by matter. Based on this assumption, Fresnel was able to explain the aberration of light and many optical phenomena.

text: One of them was developed by

text: Fresnel

text: (and subsequently Lorentz). This model (Stationary Aether Theory) supposed that light propagates as a transverse wave and aether is partially dragged with a certain coefficient by matter. Based on this assumption, Fresnel was able to explain the

text: aberration of light

text: and many optical phenomena.

text: Electromagnetic radiation with a wavelength between 380 nm and 760 nm (400–790 terahertz) is detected by the human eye and perceived as visible light. Other wavelengths, especially near infrared (longer than 760 nm) and ultraviolet (shorter than 380 nm) are also sometimes referred to as light, especially when the visibility to humans is not relevant. White light is a combination of lights of different wavelengths in the visible spectrum. Passing white light through a prism splits it up into the several colors of light observed in the visible spectrum between 400 nm and 780 nm.

text: Electromagnetic radiation with a

text: wavelength

text: between 380

text: nm

text: and 760 nm (400–790 terahertz) is detected by the human eye and perceived as visible light. Other wavelengths, especially near infrared (longer than 760 nm) and ultraviolet (shorter than 380 nm) are also sometimes referred to as light, especially when the visibility to humans is not relevant. White light is a combination of lights of different wavelengths in the visible spectrum. Passing white light through a prism splits it up into the several colors of light observed in the visible spectrum between 400 nm and 780 nm.

text: Manual transmissions often feature a driver-operated clutch and a movable gear stick. Most automobile manual transmissions allow the driver to select any forward gear ratio ("gear") at any time, but some, such as those commonly mounted on motorcycles and some types of racing cars, only allow the driver to select the next-higher or next-lower gear. This type of transmission is sometimes called a sequential manual transmission.

text: Manual transmissions often feature a

text: driver

text: -operated

text: clutch

text: and a movable

text: gear stick

text: . Most automobile manual transmissions allow the driver to select any forward

text: gear ratio

text: ("gear") at any time, but some, such as those commonly mounted on

text: motorcycle

text: s and some types of racing cars, only allow the driver to select the next-higher or next-lower gear. This type of transmission is sometimes called a

text: sequential manual transmission

text: In fluorescence the visible light component—sometimes known as "white light"—tends to be reflected and perceived normally, as colour; while the UV component of light is modified, 'stepped down' energetically into longer wavelengths, producing additional visible light frequencies, which are then emitted alongside the reflected white light. Human eyes perceive these changes as the unusual 'glow' of fluorescence.

text: In fluorescence the

text: visible light

text: component—sometimes known as "

text: white light

text: "—tends to be reflected and perceived normally, as colour; while the UV component of light is modified, 'stepped down' energetically into longer wavelengths, producing additional visible light frequencies, which are then emitted alongside the reflected white light. Human eyes perceive these changes as the unusual 'glow' of fluorescence.

text: In 1890, Panhard used a chain-drive with a Daimler engine in a horseless carriage. Industrial marketing has since then coined spectacular names for various vehicle parts. Changing from the Locomobile, a 1906 race-car to what is now called the automobile, advertisers used design wording from the engineering departments to give new ideas a desirable appeal for sales promotions. From 1932, synchronizer mechanisms began to appear in automotive transmissions. The split-off of automotive transmission types that has prevailed in engineering designs uses three major categories: automatic, manual, and non-synchronous. Some of the differences are improvements, including the continuously variable transmission installed in hybrid vehicles that are powered partly by an internal combustion engine, and partly by an electric motor. The concepts of transmission continue to employ methods for transferring the most conceivably efficient use of power.

text: In 1890,

text: Panhard

text: used a chain-drive with a

text: Daimler

text: engine in a

text: horseless carriage

text: . Industrial marketing has since then coined spectacular names for various vehicle parts. Changing from the

text: Locomobile

text: , a 1906 race-car to what is now called the

text: automobile

text: , advertisers used design wording from the engineering departments to give new ideas a desirable appeal for sales promotions. From 1932, synchronizer mechanisms began to appear in automotive transmissions. The split-off of automotive transmission types that has prevailed in engineering designs uses three major categories:

text: automatic

text: manual

text: , and non-synchronous. Some of the differences are improvements, including the

text: continuously variable transmission

text: installed in

text: hybrid vehicle

text: s that are powered partly by an

text: internal combustion engine

text: , and partly by an electric motor. The concepts of transmission continue to employ methods for transferring the most conceivably efficient use of power.

text: A viable way of building light dark matter models is thus by postulating new light bosons. This increases the annihilation cross section and reduces the coupling of dark matter particles to the Standard Model making them consistent with accelerator experiments.

text: The main materials used for the nano-studs are silver, gold, and aluminium. However, gold and silver are not very efficient, as they absorb much of the light in the visible spectrum, which contains most of the energy present in sunlight, reducing the amount of light reaching the cell. Aluminium, on the other hand, absorbs only ultraviolet radiation, and reflects both visible and infra-red light, so energy loss is minimized on that front. Aluminium is therefore capable of increasing the efficiency of the cell by up to 22% (in lab conditions).

text: The main materials used for the nano-studs are

text: silver

text: gold

text: , and

text: aluminium

text: . However, gold and silver are not very efficient, as they absorb much of the light in the visible spectrum, which contains most of the energy present in sunlight, reducing the amount of light reaching the cell. Aluminium, on the other hand, absorbs only ultraviolet radiation, and reflects both visible and infra-red light, so energy loss is minimized on that front. Aluminium is therefore capable of increasing the efficiency of the cell by up to 22% (in lab conditions).

text: Optics, the study of light, is concerned not only with visible light but also with infrared and ultraviolet radiation, which exhibit all of the phenomena of visible light except visibility, e.g., reflection, refraction, interference, diffraction, dispersion, and polarization of light. Heat is a form of energy, the internal energy possessed by the particles of which a substance is composed; thermodynamics deals with the relationships between heat and other forms of energy. Electricity and magnetism have been studied as a single branch of physics since the intimate connection between them was discovered in the early 19th century; an electric current gives rise to a magnetic field, and a changing magnetic field induces an electric current. Electrostatics deals with electric charges at rest, electrodynamics with moving charges, and magnetostatics with magnetic poles at rest.

text: Optics

text: , the study of

text: light

text: , is concerned not only with

text: visible light

text: but also with

text: infrared

text: and

text: ultraviolet radiation

text: , which exhibit all of the phenomena of visible light except visibility, e.g., reflection, refraction, interference, diffraction, dispersion, and polarization of light.

text: Heat

text: is a form of

text: energy

text: , the internal energy possessed by the particles of which a substance is composed; thermodynamics deals with the relationships between heat and other forms of energy.

text: Electricity

text: and

text: magnetism

text: have been studied as a single branch of physics since the intimate connection between them was discovered in the early 19th century; an

text: electric current

text: gives rise to a

text: magnetic field

text: , and a changing magnetic field induces an electric current.

text: Electrostatics

text: deals with

text: electric charge

text: s at rest,

text: electrodynamics

text: with moving charges, and

text: magnetostatics

text: with magnetic poles at rest.

text: Face-on lenticulars are difficult to distinguish from ellipticals of type E0, making the classification of many such galaxies uncertain. When viewed edge-on, prominent dust-lanes are sometimes visible in absorption against the light of stars in the disk.

text: Face-on lenticulars are difficult to distinguish from ellipticals of type E0, making the classification of many such galaxies uncertain. When viewed edge-on, prominent dust-lanes are sometimes visible in

text: absorption

text: against the light of stars in the disk.

text: In January 1902 the British army adopted a universal khaki uniform for home service wear, the Service Dress, after experience with lighter khaki drill in India and South Africa. The traditional scarlet, blue and green uniforms were however retained for full dress and off duty "walking out dress" wear. Details of these colourful uniforms varied greatly between regiments and branches  of the army. The early use of camouflage in the form of plain khaki reflected the exigencies of colonial war and the freedom allowed, and taken, by many of the officers who fought it. The adoption of khaki for active service resulted from the development of weapons of greater accuracy range combined with smokeless powder during the late 19th century, making low-visibility on the battlefield a matter of priority.

text: In January 1902 the British army adopted a universal khaki uniform for home service wear, the

text: Service Dress

text: , after experience with lighter khaki drill in India and South Africa. The traditional scarlet, blue and green uniforms were however retained for full dress and off duty "walking out dress" wear. Details of these colourful uniforms varied greatly between regiments and branches  of the army. The early use of camouflage in the form of plain khaki reflected the exigencies of

text: colonial war

text: and the freedom allowed, and taken, by many of the officers who fought it. The adoption of khaki for active service resulted from the development of weapons of greater accuracy range combined with smokeless powder during the late 19th century, making low-visibility on the battlefield a matter of priority.

text: Reflection is the change in direction of a wavefront at an interface between two different media so that the wavefront returns into the medium from which it originated. Common examples include the reflection of light, sound and water waves. The law of reflection says that for specular reflection the angle at which the wave is incident on the surface equals the angle at which it is reflected. Mirrors exhibit specular reflection.

text: Reflection is the change in direction of a

text: wavefront

text: at an

text: interface

text: between two different

text: media

text: so that the wavefront returns into the medium from which it originated. Common examples include the reflection of

text: light

text: sound

text: and

text: water wave

text: s. The law of reflection says that for

text: specular reflection

text: the angle at which the wave is incident on the surface equals the angle at which it is reflected.

text: Mirror

text: s exhibit specular reflection.

text: Optics is the branch of physics which involves the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultraviolet, and infrared light. Because light is an electromagnetic wave, other forms of electromagnetic radiation such as X-rays, microwaves, and radio waves exhibit similar properties.

text: Optics is the branch of

text: physics

text: which involves the behaviour and properties of

text: light

text: , including its interactions with

text: matter

text: and the construction of

text: instruments

text: that use or

text: detect

text: it. Optics usually describes the behaviour of

text: visible

text: ultraviolet

text: , and

text: infrared

text: light. Because light is an

text: electromagnetic wave

text: , other forms of

text: electromagnetic radiation

text: such as

text: X-ray

text: s,

text: microwave

text: s, and

text: radio wave

text: s exhibit similar properties.

text: Multiple reflection by two or more reflecting surfaces has been known since antiquity and was described by as such by Giambattista della Porta in his Magia Naturalis (1558-1589). In in 1646 Athanasius Kircher described an experiment with a construction of two mirrors, which could be opened and closed like a book and positioned in various angles, showing regular polygon figures consisting of reflected aliquot sectors of 360°. Mr. Bradley's New Improvements in Planting and Gardening (1717) described a similar construction to be placed on geometrical drawings to show an image with multiplied reflection. However, an optimal configuration that produces the full effects of the kaleidoscope have not been recorded before 1815.

text: Multiple reflection by two or more reflecting surfaces has been known since antiquity and was described by as such by

text: Giambattista della Porta

text: in his

text: Magia Naturalis

text: (1558-1589). In in 1646

text: Athanasius Kircher

text: described an experiment with a construction of two mirrors, which could be opened and closed like a book and positioned in various angles, showing regular polygon figures consisting of reflected aliquot sectors of 360°. Mr. Bradley's New Improvements in Planting and Gardening (1717) described a similar construction to be placed on geometrical drawings to show an image with multiplied reflection. However, an optimal configuration that produces the full effects of the kaleidoscope have not been recorded before 1815.

text: The theory of operation on which Hieronymus Machines are based is that all matter emits a kind of "radiation" that is not electromagnetic, but exhibits some of the characteristics of both light and electricity. The quality of this emanation is unique to every kind of matter, and therefore can be utilized for detection and analysis. Hieronymus coined the term "eloptic energy" to describe this radiation (from the words "electrical" and "optical".) All of his machines were designed to detect and manipulate this eloptic energy. Eloptic emanations have never been detected by instruments designed to measure electromagnetic energies, and no other evidence or mathematical proof for their existence have been produced, so the theory is considered pseudoscientific and is not accepted by mainstream science.

text: The theory of operation on which Hieronymus Machines are based is that all matter emits a kind of "radiation" that is not

text: electromagnetic

text: , but exhibits some of the characteristics of both light and electricity. The quality of this emanation is unique to every kind of matter, and therefore can be utilized for detection and analysis. Hieronymus coined the term "eloptic energy" to describe this radiation (from the words "electrical" and "optical".) All of his machines were designed to detect and manipulate this eloptic energy. Eloptic emanations have never been detected by instruments designed to measure electromagnetic energies, and no other evidence or mathematical proof for their existence have been produced, so the theory is considered pseudoscientific and is not accepted by mainstream science.

text: Automatic transmissions are less common on motorcycles than manual, and are mostly found only on scooters and some custom cruisers and exotic sports bikes. Types include continuously variable transmission, semi-automatic transmission and dual clutch transmission.

text: Automatic transmissions are less common on motorcycles than manual, and are mostly found only on scooters and some custom cruisers and exotic sports bikes. Types include

text: continuously variable transmission

text: semi-automatic transmission

text: and

text: dual clutch transmission

text: There were two cameras for each spectrograph, one designated the primary and the second being redundant in case of failure of the first. The cameras were named LWP, LWR, SWP and SWR where P stands for prime, R for redundant and LW/SW for long/short wavelength. The cameras were television cameras, sensitive only to visible light, and light gathered by the telescope and spectrographs first fell on a UV-to-visible converter. This was a caesium-tellurium cathode, which was inert when exposed to visible light, but which gave off electrons when struck by UV photons due to the photoelectric effect. The electrons were then detected by the TV cameras. The signal could be integrated for up to many hours, before being transmitted to Earth at the end of the exposure.

text: There were two cameras for each spectrograph, one designated the primary and the second being redundant in case of failure of the first. The cameras were named LWP, LWR, SWP and SWR where P stands for prime, R for redundant and LW/SW for long/short wavelength. The cameras were

text: television camera

text: s, sensitive only to visible light, and light gathered by the telescope and spectrographs first fell on a UV-to-visible converter. This was a

text: caesium

text: tellurium

text: cathode, which was inert when exposed to visible light, but which gave off electrons when struck by UV photons due to the

text: photoelectric effect

text: . The electrons were then detected by the TV cameras. The signal could be integrated for up to many hours, before being transmitted to Earth at the end of the exposure.

text: When the lights are bright in the main room and dark in the blue room, the reflected image cannot be seen. When the lighting in the blue room is increased, often with the main room lights dimming to make the effect more pronounced, the reflection becomes visible and the objects within the blue room seem to appear in thin air. A common variation uses two blue rooms, one behind the glass and one to the side, which can be switched visible or invisible by alternating the lighting.

text: (a) The ray of the “Ever Darkness” becomes, as it is emitted, a ray of effulgent light or life, and flashes into the “Germ” — the point in the Mundane Egg, represented by matter in its abstract sense.  But the term “Point” must not be understood as applying to any particular point in Space, for a germ exists in the centre of every atom, and these collectively form “the Germ;” or rather, as no atom can be made visible to our physical eye, the collectivity of these (if the term can be applied to something which is boundless and infinite) forms the noumenon of eternal and indestructible matter.

text: Opacity is the measure of impenetrability to electromagnetic or other kinds of radiation, especially visible light.  In radiative transfer, it describes the absorption and scattering of radiation in a medium, such as a plasma, dielectric, shielding material, glass, etc.  An opaque object is neither transparent (allowing all light to pass through) nor translucent (allowing some light to pass through).  When light strikes an interface between two substances, in general some may be reflected, some absorbed, some scattered, and the rest transmitted (also see refraction). Reflection can be diffuse, for example light reflecting off a white wall, or specular, for example light reflecting off a mirror. An opaque substance transmits no light, and therefore reflects, scatters, or absorbs all of it.  Both mirrors and carbon black are opaque.  Opacity depends on the frequency of the light being considered.  For instance, some kinds of glass, while transparent in the visual range, are largely opaque to ultraviolet light.  More extreme frequency-dependence is visible in the absorption lines of cold gases. Opacity can be quantified in many ways; for example, see the article mathematical descriptions of opacity.

text: Opacity is the measure of impenetrability to

text: electromagnetic

text: or other kinds of

text: radiation

text: , especially visible

text: light

text: .  In

text: radiative transfer

text: , it describes the absorption and scattering of radiation in a

text: medium

text: , such as a

text: plasma

text: dielectric

text: shielding material

text: , glass, etc.  An opaque object is neither

text: transparent

text: (allowing all light to pass through) nor

text: translucent

text: (allowing some light to pass through).  When light strikes an interface between two substances, in general some may be reflected, some absorbed, some scattered, and the rest transmitted (also see

text: refraction

text: ). Reflection can be

text: diffuse

text: , for example light reflecting off a white wall, or

text: specular

text: , for example light reflecting off a mirror. An opaque substance transmits no light, and therefore reflects, scatters, or absorbs all of it.  Both

text: mirror

text: s and

text: carbon black

text: are opaque.  Opacity depends on the

text: frequency

text: of the light being considered.  For instance, some kinds of

text: glass

text: , while transparent in the

text: visual range

text: , are largely opaque to

text: ultraviolet

text: light.  More extreme frequency-dependence is visible in the

text: absorption line

text: s of cold

text: gas

text: es. Opacity can be quantified in many ways; for example, see the article

text: mathematical descriptions of opacity

text: The process of absorption means that a substance captures and transforms energy. The absorbent distributes the material it captures throughout whole and adsorbent only distributes it through the surface.

text: Ellipsometry can also be done as imaging ellipsometry by using a CCD camera as a detector. This provides a real time contrast image of the sample, which provides information about film thickness and refractive index. Advanced imaging ellipsometer technology operates on the principle of classical null ellipsometry and real-time ellipsometric contrast imaging.  Imaging ellipsometry is based on the concept of nulling.  In ellipsometry, the film under investigation is placed onto a reflective substrate.  The film and the substrate have different refractive indexes.  In order to obtain data about film thickness, the light reflecting off of the substrate must be nulled.  Nulling is achieved by adjusting the analyzer and polarizer so that all reflected light off of the substrate is extinguished.  Due to the difference in refractive indexes, this will allow the sample to become very bright and clearly visible. The light source consists of a monochromatic laser of the desired wavelength. A common wavelength that is used is 532 nm green laser light.  Since only intensity of light measurements are needed, almost any type of camera can be implemented as the CCD, which is useful if building an ellipsometer from parts.   Typically, imaging ellipsometers are configured in such a way so that the laser (L) fires a beam of light which immediately passes through a linear polarizer (P).  The linearly polarized light then passes through a quarter wavelength compensator (C) which transforms the light into elliptically polarized light.   This elliptically polarized light then reflects off the sample (S), passes through the analyzer (A) and is imaged onto a CCD camera by a long working distance objective. The analyzer here is another polarizer identical to the P, however, this polarizer serves to help quantify the change in polarization and is thus given the name analyzer.  This design is commonly referred to as a LPCSA configuration.

text: Ellipsometry can also be done as

text: imaging ellipsometry

text: by using a

text: CCD

text: camera as a detector. This provides a real time contrast image of the sample, which provides information about film thickness and

text: refractive index

text: . Advanced imaging ellipsometer technology operates on the principle of classical null ellipsometry and real-time ellipsometric contrast imaging.  Imaging ellipsometry is based on the concept of nulling.  In ellipsometry, the film under investigation is placed onto a reflective substrate.  The film and the substrate have different refractive indexes.  In order to obtain data about film thickness, the light reflecting off of the substrate must be nulled.  Nulling is achieved by adjusting the analyzer and polarizer so that all reflected light off of the substrate is extinguished.  Due to the difference in refractive indexes, this will allow the sample to become very bright and clearly visible. The

text: light source

text: consists of a monochromatic laser of the desired wavelength. A common wavelength that is used is 532 nm green laser light.  Since only intensity of light measurements are needed, almost any type of camera can be implemented as the CCD, which is useful if building an ellipsometer from parts.   Typically, imaging ellipsometers are configured in such a way so that the laser (L) fires a beam of light which immediately passes through a linear polarizer (P).  The linearly polarized light then passes through a quarter wavelength compensator (C) which transforms the light into elliptically polarized light.   This elliptically polarized light then reflects off the sample (S), passes through the analyzer (A) and is imaged onto a CCD camera by a long working distance objective. The analyzer here is another polarizer identical to the P, however, this polarizer serves to help quantify the change in polarization and is thus given the name analyzer.  This design is commonly referred to as a LPCSA configuration.

text: Most of the time, it is a combination of the above that happens to the light that hits an object. The states in different materials vary in the range of energy that they can absorb. Most glasses, for example, block ultraviolet (UV) light. What happens is the electrons in the glass absorb the energy of the photons in the UV range while ignoring the weaker energy of photons in the visible light spectrum. But there are also existing special glass types, like special types of borosilicate glass or quartz that are UV-permeable and thus allow a high transmission of ultra violet light.

text: Most of the time, it is a combination of the above that happens to the light that hits an object. The states in different materials vary in the range of energy that they can absorb. Most glasses, for example, block ultraviolet (UV) light. What happens is the electrons in the glass absorb the energy of the photons in the UV range while ignoring the weaker energy of photons in the visible light spectrum. But there are also existing special

text: glass

text: types, like special types of

text: borosilicate glass

text: or quartz that are UV-permeable and thus allow a high transmission of ultra violet light.

text: Certain image capturing devices are capable of producing images through materials that are opaque to visible light, including clothing. These devices form images by using electromagnetic radiation outside the visible range. Infrared and terahertz-wave cameras are capable of creating images through clothing, though these images differ from what would be created with visible light.

text: A variety of solid-state and vacuum devices have been explored for use in different parts of the UV spectrum. Many approaches seek to adapt visible light-sensing devices, but these can suffer from unwanted response to visible light and various instabilities. Ultraviolet can be detected by suitable photodiodes and photocathodes, which can be tailored to be sensitive to different parts of the UV spectrum. Sensitive ultraviolet photomultipliers are available. Spectrometers and radiometers are made for measurement of UV radiation. Silicon detectors are used across the spectrum.

text: A variety of solid-state and vacuum devices have been explored for use in different parts of the UV spectrum. Many approaches seek to adapt visible light-sensing devices, but these can suffer from unwanted response to visible light and various instabilities. Ultraviolet can be detected by suitable

text: photodiode

text: s and

text: photocathode

text: s, which can be tailored to be sensitive to different parts of the UV spectrum. Sensitive ultraviolet

text: photomultiplier

text: s are available.

text: Spectrometer

text: s and

text: radiometer

text: s are made for measurement of UV radiation. Silicon detectors are used across the spectrum.

text: The algorithm considers two main processes: Reflection and Visibility. Reflection process simulates the light reflection mechanism, while visibility simulates the visibility of matching patterns. These two processes are used as a search strategy to find the global optimal solution. The formulation of finding the new solution (newP) by using reflection and visibility is as follows:

text: The visible and infrared spectrum of the reflected sunlight is used to infer physical and chemical properties of the surface of a body. Some objects are brighter (reflect more) in longer wavelengths (red). Consequently, in visible light they will appear redder than objects showing no dependence of reflectance on the wavelength.

text: The visible and

text: infrared

text: spectrum

text: of the reflected sunlight is used to infer physical and chemical properties of the surface of a body. Some objects are brighter (reflect more) in longer wavelengths (red). Consequently, in visible light they will appear redder than objects showing no dependence of reflectance on the wavelength.

text: In astronomy and cosmology, light dark matter is dark matter weakly interacting massive particle (WIMP) candidates with masses less than 1 GeV. These particles are heavier than warm dark matter and hot dark matter, but are lighter than the traditional forms of cold dark matter. The Lee-Weinberg bound  limits the mass of the favored dark matter candidate, WIMPs, that interact via the weak interaction to

text: In

text: astronomy

text: and

text: cosmology

text: , light dark matter is

text: dark matter

text: weakly interacting massive particle

text: (WIMP) candidates with masses less than 1

text: GeV

text: . These particles are heavier than

text: warm dark matter

text: and

text: hot dark matter

text: , but are lighter than the traditional forms of

text: cold dark matter

text: . The

text: Lee

text: Weinberg

text: bound  limits the mass of the favored dark matter candidate, WIMPs, that interact via the weak interaction to

text: In the context of this article, FTL is the transmission of information or matter faster than c, a constant equal to the speed of light in a vacuum, which is 299,792,458 m/s (by definition of the metre) or about 186,282.397 miles per second. This is not quite the same as traveling faster than light, since:

text: In the context of this article, FTL is the transmission of information or matter faster than c, a constant equal to the

text: speed of light

text: in a vacuum, which is 299,792,458 m/s (by definition of the metre) or about 186,282.397 miles per second. This is not quite the same as traveling faster than light, since:

text: In chemistry, spectrophotometry is the quantitative measurement of the reflection or transmission properties of a material as a function of wavelength. It is more specific than the general term electromagnetic spectroscopy in that spectrophotometry deals with visible light, near-ultraviolet, and near-infrared, but does not cover time-resolved spectroscopic techniques.

text: In

text: chemistry

text: , spectrophotometry is the quantitative measurement of the reflection or transmission properties of a material as a function of wavelength. It is more specific than the general term

text: electromagnetic spectroscopy

text: in that spectrophotometry deals with

text: visible

text: light, near-

text: ultraviolet

text: , and near-

text: infrared

text: , but does not cover

text: time-resolved spectroscopic

text: techniques.

text: A safety reflector aids visibility of a person or vehicle visible to on the road, as it reflects light from headlights of vehicles. Safety reflectors are especially useful where there are no streetlights.

text: A safety reflector aids visibility of a person or vehicle visible to on the road, as it reflects light from

text: headlight

text: s of vehicles. Safety reflectors are especially useful where there are no

text: streetlight

text: s.

text: Although the ice is clear, scattering of light by the crystal facets and hollows/imperfections mean that the crystals often appear white in color due to diffuse reflection of the whole spectrum of light by the small ice particles.  The shape of the snowflake is determined broadly by the temperature and humidity at which it is formed. Rarely, at a temperature of around , snowflakes can form in threefold symmetry—triangular snowflakes. The most common snow particles are visibly irregular, although near-perfect snowflakes may be more common in pictures because they are more visually appealing.  No two snowflakes are alike, which grow at different rates and in different patterns depending on the changing temperature and humidity within the atmosphere that the snowflake falls through on its way to the ground.  The METAR code for snow is SN, while snow showers are coded SHSN.

text: Although the ice is clear, scattering of light by the crystal facets and hollows/imperfections mean that the crystals often appear white in color due to

text: diffuse reflection

text: of the whole

text: spectrum

text: of

text: light

text: by the small ice particles.  The shape of the snowflake is determined broadly by the temperature and humidity at which it is formed. Rarely, at a temperature of around , snowflakes can form in threefold symmetry—triangular snowflakes. The most common snow particles are visibly irregular, although near-perfect snowflakes may be more common in pictures because they are more visually appealing.  No two snowflakes are alike, which grow at different rates and in different patterns depending on the changing temperature and humidity within the atmosphere that the snowflake falls through on its way to the ground.  The METAR code for snow is SN, while snow showers are coded SHSN.

text: The distribution of power that a black body emits with varying frequency is described by Planck's law. At any given temperature, there is a frequency f at which the power emitted is a maximum. Wien's displacement law, and the fact that the frequency is inversely proportional to the wavelength, indicates that the peak frequency f is proportional to the absolute temperature T of the black body. The photosphere of the sun, at a temperature of approximately 6000 K, emits radiation principally in the (humanly) visible portion of the electromagnetic spectrum. Earth's atmosphere is partly transparent to visible light, and the light reaching the surface is absorbed or reflected. Earth's surface emits the absorbed radiation, approximating the behavior of a black body at 300 K with spectral peak at f. At these lower frequencies, the atmosphere is largely opaque and radiation from Earth's surface is absorbed or scattered by the atmosphere. Though some radiation escapes into space, most is absorbed and then re-emitted by atmospheric gases. It is this spectral selectivity of the atmosphere that is responsible for the planetary greenhouse effect, contributing to global warming and climate change in general (but also critically contributing to climate stability when the composition and properties of the atmosphere are not changing).

text: The distribution of power that a black body emits with varying frequency is described by

text: Planck's law

text: . At any given temperature, there is a frequency f at which the power emitted is a maximum. Wien's displacement law, and the fact that the frequency is inversely proportional to the wavelength, indicates that the peak frequency f is proportional to the absolute temperature T of the black body. The photosphere of the sun, at a temperature of approximately 6000 K, emits radiation principally in the (humanly) visible portion of the electromagnetic spectrum. Earth's atmosphere is partly transparent to visible light, and the light reaching the surface is absorbed or reflected. Earth's surface emits the absorbed radiation, approximating the behavior of a black body at 300 K with spectral peak at f. At these lower frequencies, the atmosphere is largely opaque and radiation from Earth's surface is absorbed or scattered by the atmosphere. Though some radiation escapes into space, most is absorbed and then re-emitted by atmospheric gases. It is this spectral selectivity of the atmosphere that is responsible for the planetary

text: greenhouse effect

text: , contributing to

text: global warming

text: and

text: climate change

text: in general (but also critically contributing to climate stability when the composition and properties of the atmosphere are not changing).

text: In the light of article 108(2) of the constitution of the united republic and the provisions of the Judicature and Application of laws Act, the high court has original jurisdiction over all matters that are outside the jurisdiction of the courts subordinate to it.  For example, proceedings where the value of the subject matter exceeds that of the district or resident magistrate courts, such cases are to be tried by the High Court. The High court also has original jurisdiction over all naval affairs or admiral matters.

text: Some skylights have expensive glazing that partially reduces summer solar heat gain, while still allowing some visible light transmission. However, if visible light can pass through it, so can some radiant heat gain (they are both electromagnetic radiation waves).

text: Some skylights have expensive glazing that partially reduces summer solar heat gain, while still allowing some visible light transmission. However, if visible light can pass through it, so can some radiant heat gain (they are both

text: electromagnetic radiation

text: waves).

text: The inverse or time-reversed process of absorption is thermal radiation. Much of the thermal energy in matter consists of random motion of charged particles, and this energy can be radiated away from the matter. The resulting radiation may subsequently be absorbed by another piece of matter, with the deposited energy heating the material.

text: This absorption of light in the ultraviolet to visible spectrum can be quantified using ultraviolet–visible spectroscopy, and forms the basis for the entire field of photochemistry.

text: This absorption of light in the ultraviolet to visible spectrum can be quantified using

text: ultraviolet–visible spectroscopy

text: , and forms the basis for the entire field of

text: photochemistry

text: Reflected color can be measured using a spectrophotometer (also called spectroreflectometer or reflectometer), which takes measurements in the visible region (and a little beyond) of a given color sample. If the custom of taking readings at 10 nanometer increments is followed, the visible light range of 400-700 nm will yield 31 readings. These readings are typically used to draw the sample's spectral reflectance curve (how much it reflects, as a function of wavelength)—the most accurate data that can be provided regarding its characteristics.

text: Reflected color can be measured using a spectrophotometer (also called spectroreflectometer or reflectometer), which takes measurements in the visible region (and a little beyond) of a given color sample. If the custom of taking readings at 10

text: nanometer

text: increments is followed, the

text: visible light

text: range of 400-700 nm will yield 31 readings. These readings are typically used to draw the sample's

text: spectral reflectance

text: curve (how much it reflects, as a function of wavelength)—the most accurate data that can be provided regarding its characteristics.

text: The newly developed computer-controlled 4-speed automatic transmission, called the 4EAT in both FWD and AWD guises, uses a lock up torque converter, and does not use an overdrive feature. The transmission had a feature where it could be instructed to ignore 1st gear from a standing stop to assist driving on traction limited situations, such as ice and snow. The system was activated by depressing a button on the gearshift selector marked "Manual" and moving the gearshift from the "D" position down to "3rd". A yellow indicator light marked "Manual" also lights up at the bottom center of the instrument cluster when the system is ready to be used. The car would then start in 2nd gear, and not 1st, then as the car gained speed would shift up to 3rd, locking out 4th gear. The transmission's computer also splits the delivered torque 50:50 between the front and rear wheels. Once the car stopped, the transmission would start back in 2nd and not 1st, until the system was disengaged with the "Manual" button or upshifting to 4th.

text: The newly developed computer-controlled 4-speed

text: automatic transmission

text: , called the

text: in both FWD and AWD guises, uses a

text: lock up torque converter

text: , and does not use an

text: overdrive

text: feature. The transmission had a feature where it could be instructed to ignore 1st gear from a standing stop to assist driving on traction limited situations, such as ice and snow. The system was activated by depressing a button on the gearshift selector marked "Manual" and moving the gearshift from the "D" position down to "3rd". A yellow indicator light marked "Manual" also lights up at the bottom center of the instrument cluster when the system is ready to be used. The car would then start in 2nd gear, and not 1st, then as the car gained speed would shift up to 3rd, locking out 4th gear. The transmission's computer also splits the delivered torque 50:50 between the front and rear wheels. Once the car stopped, the transmission would start back in 2nd and not 1st, until the system was disengaged with the "Manual" button or upshifting to 4th.

text: In fact, reflection of light may occur whenever light travels from a medium of a given refractive index into a medium with a different refractive index. In the most general case, a certain fraction of the light is reflected from the interface, and the remainder is refracted.  Solving Maxwell's equations for a light ray striking a boundary allows the derivation of the Fresnel equations, which can be used to predict how much of the light is reflected, and how much is refracted in a given situation. This is analogous to the way impedance mismatch in an electric circuit causes reflection of signals.  Total internal reflection of light from a denser medium occurs if the angle of incidence is above the critical angle.

text: In fact, reflection of light may occur whenever light travels from a medium of a given

text: refractive index

text: into a medium with a different refractive index. In the most general case, a certain fraction of the light is reflected from the interface, and the remainder is

text: refracted

text: .  Solving

text: Maxwell's equations

text: for a light ray striking a boundary allows the derivation of the

text: Fresnel equations

text: , which can be used to predict how much of the light is reflected, and how much is refracted in a given situation. This is analogous to the way

text: impedance mismatch

text: in an electric circuit causes reflection of signals.

text: Total internal reflection

text: of light from a denser medium occurs if the angle of incidence is above the

text: critical angle

text: Because manual transmissions are mechanically simpler, are more easily manufactured, and have fewer moving parts than automatic transmissions, they require less maintenance and are easier as well as cheaper to repair. Due to their mechanical simplicity, they often last longer than automatic transmissions when used by a skilled driver. Typically, there are no electrical components, pumps and cooling mechanisms in a manual transmission, other than an internal switch to activate reversing lighting. These attributes become extremely vital with a vehicle stuck in mud, snow, etc. The back and forth rocking motion of the vehicle drivers use to dislodge a stuck vehicle can destroy automatic transmissions. Clutches are a wear item that may need to be replaced at some point in the vehicle's lifespan, however the service life of the clutch depends on the operating conditions that it is subjected to.

text: Absorption is strongly correlated with openness to experience. Studies using factor analysis have suggested that the fantasy, aesthetics, and feelings facets of the NEO PI-R Openness to Experience scale are closely related to absorption and predict hypnotisability, whereas the remaining three facet scales of ideas, actions, and values are largely unrelated to these constructs. Absorption is unrelated to extraversion or neuroticism. One study found a positive correlation between absorption and need for cognition. Absorption has a strong relationship to self-transcendence in the Temperament and Character Inventory.

text: Absorption is strongly correlated with

text: openness to experience

text: . Studies using

text: factor analysis

text: have suggested that the fantasy, aesthetics, and feelings facets of the NEO PI-R Openness to Experience scale are closely related to absorption and predict hypnotisability, whereas the remaining three facet scales of ideas, actions, and values are largely unrelated to these constructs. Absorption is unrelated to

text: extraversion

text: or

text: neuroticism

text: . One study found a positive correlation between absorption and

text: need for cognition

text: . Absorption has a strong relationship to

text: self-transcendence

text: in the

text: Temperament and Character Inventory

text: Another factor that will influence the visibility of the traps is the direction of the trap. The decision as to which color should be spread or choked is usually decided upon the relative luminance of the colors in question. The ‘lighter’ color should always be spread into the darker. Again this reflects the way the human eye perceives color: since the darker colors define the shapes we see, distortion of the lighter color will result in less visible distortion overall. The ‘lightness’ or ‘darkness’ of a color is usually defined as its ‘neutral density’.

text: If (as is always the case to some extent) the compounds A and B have different absorption spectra, then there may exist wavelengths of light where σ is high and σ is low. Irradiation at these wavelengths will provide photostationary states that contain mostly B. Likewise, wavelengths that give photostationary states of predominantly A may exist. This is particularly likely in compounds such as some photochromics, where A and B have entirely different absorption bands. Compounds that may be readily switched in this way find utility in devices such as molecular switches and optical data storage.

text: If (as is always the case to some extent) the compounds A and B have different

text: absorption spectra

text: , then there may exist wavelengths of light where σ is high and σ is low. Irradiation at these wavelengths will provide photostationary states that contain mostly B. Likewise, wavelengths that give photostationary states of predominantly A may exist. This is particularly likely in compounds such as some photochromics, where A and B have entirely different

text: absorption band

text: s. Compounds that may be readily switched in this way find utility in devices such as

text: molecular switch

text: es and

text: optical data storage

text: The above shows the π-electronic energy levels of an organic molecule.  Absorption of radiation is followed by molecular vibration to the S state.  This is followed by a de-excitation to the S state called fluorescence.  The population of triplet states is also possible by other means.  The triplet states decay with a much longer decay time than singlet states, which results in what is called the slow component of the decay process (the fluorescence process is called the fast component). Depending on the particular energy loss of a certain particle (dE/dx), the "fast" and "slow" states are occupied in different proportions. The relative intensities in the light output of these states thus differs for different dE/dx. This property of scintillators allows for pulse shape discrimination: it is possible to identify which particle was detected by looking at the pulse shape. Of course, the difference in shape is visible in the trailing side of the pulse, since it is due to the decay of the excited states.

text: The above classifications hold true in any frame of reference; that is, an event judged to be in the light cone by one observer, will also be judged to be in the same light cone by all other observers, no matter their frame of reference. This is why the concept is so powerful.

text: The massive surveillance tower once made the Stöberhai a very prominent feature with the Harz mountains. All that is left is a relatively puny transmission tower, which is nevertheless visible from Sankt Andreasberg and the surrounding mountains.

text: Mist makes a beam of light visible from the side via refraction and reflection on the suspended water droplets.

text: Mist makes a

text: beam of light

text: visible from the side via

text: refraction

text: and

text: reflection

text: on the suspended water droplets.

text: Although a successful demonstration, three notable limitations can be shown. First, since its effectiveness was only in the  microwave spectrum the small object is somewhat invisible only at microwave frequencies. This means invisibility had not been achieved for the human eye, which sees only within the visible spectrum. This is because the wavelengths of the visible spectrum are tangibly shorter than microwaves. However, this was considered the first step toward a cloaking device for visible light, although more advanced nanotechnology-related techniques would be needed due to light's short wavelengths. Second, only small objects can be made to appear as the surrounding air. In the case of the 2006 proof of cloaking demonstration, the hidden from view object, a copper cylinder, would have to be less than five inches in diameter, and less than one half inch tall. Third, cloaking can only occur over a narrow frequency band, for any given demonstration. This means that a broad band cloak, which works across the electromagnetic spectrum, from radio frequencies to microwave to the visible spectrum, and to x-ray, is not available at this time. This is due to the dispersive nature of present-day metamaterials. The coordinate transformation (transformation optics) requires extraordinary material parameters that are only approachable through the use of resonant elements, which are inherently narrow band, and dispersive at resonance.

text: Although a successful demonstration, three notable limitations can be shown. First, since its effectiveness was only in the

text: microwave spectrum

text: the small object is somewhat invisible only at microwave frequencies. This means invisibility had not been achieved for the

text: human eye

text: , which sees only within the

text: visible spectrum

text: . This is because the

text: wavelengths

text: of the visible spectrum are tangibly shorter than microwaves. However, this was considered the first step toward a cloaking device for visible light, although more advanced

text: nanotechnology-related

text: techniques would be needed due to light's short wavelengths. Second, only small objects can be made to appear as the surrounding air. In the case of the 2006 proof of cloaking demonstration, the hidden from view object, a

text: copper

text: cylinder, would have to be less than five inches in diameter, and less than one half inch tall. Third, cloaking can only occur over a narrow frequency band, for any given demonstration. This means that a broad band cloak, which works across the

text: electromagnetic spectrum

text: , from

text: radio frequencies

text: to microwave to the

text: visible spectrum

text: , and to

text: x-ray

text: , is not available at this time. This is due to the

text: dispersive nature

text: of present-day metamaterials. The coordinate transformation (

text: transformation optics

text: ) requires extraordinary material parameters that are only approachable through the use of

text: resonant

text: elements, which are inherently

text: narrow band

text: , and

text: dispersive

text: at resonance.

text: As in all neodymium-doped laser crystals, the lasing action of Nd:YVO is due to its content of neodymium ions, which may be excited by visible or infrared light, and undergo an electronic transition resulting in emission of coherent infrared light at a lower frequency, usually at 1064 nm (other transitions in Nd are available, and can be selected for by external optics).

text: As in all neodymium-doped laser crystals, the lasing action of Nd:YVO is due to its content of

text: neodymium

text: ions, which may be excited by visible or infrared light, and undergo an electronic transition resulting in emission of coherent infrared light at a lower frequency, usually at 1064 nm (other transitions in Nd are available, and can be selected for by external optics).

text: As water vapour absorbs light in the visible spectral range, its absorption can be used in spectroscopic applications (such as DOAS) to determine the amount of water vapor in the atmosphere. This is done operationally, e.g. from the GOME spectrometers on ERS and MetOp.  The weaker water vapor absorption lines in the blue spectral range and further into the UV up to its dissociation limit around 243 nm are mostly based on quantum mechanical calculations and are only partly confirmed by experiments.

text: As water vapour absorbs light in the visible spectral range, its absorption can be used in spectroscopic applications (such as

entity_name: Differential optical absorption spectroscopy

text: DOAS

text: ) to determine the amount of water vapor in the atmosphere. This is done operationally, e.g. from the

text: GOME

text: spectrometers on

text: ERS

text: and

text: MetOp

text: .  The weaker water vapor absorption lines in the blue spectral range and further into the UV up to its dissociation limit around 243 nm are mostly based on quantum mechanical calculations and are only partly confirmed by experiments.

text: The UV-visible spectrophotometer can also be configured to measure reflectance. In this case, the spectrophotometer measures the intensity of light reflected from a sample (

text: A surface built from a non-absorbing powder such as plaster, or from fibers such as paper, or from a polycrystalline material such as white marble, reflects light diffusely with great efficiency. Many common materials exhibit a mixture of specular and diffuse reflection.

text: A surface built from a non-absorbing powder such as

text: plaster

text: , or from fibers such as paper, or from a

text: polycrystalline

text: material such as white

text: marble

text: , reflects light diffusely with great efficiency. Many common materials exhibit a mixture of specular and diffuse reflection.

text: The common fluorescent lamp relies on fluorescence. Inside the glass tube is a partial vacuum and a small amount of mercury. An electric discharge in the tube causes the mercury atoms to emit mostly ultraviolet light. The tube is lined with a coating of a fluorescent material, called the phosphor, which absorbs the ultraviolet and re-emits visible light. Fluorescent lighting is more energy-efficient than incandescent lighting elements. However, the uneven spectrum of traditional fluorescent lamps may cause certain colors to appear different than when illuminated by incandescent light or daylight. The mercury vapor emission spectrum is dominated by a short-wave UV line at 254 nm (which provides most of the energy to the phosphors), accompanied by visible light emission at 436 nm (blue), 546 nm (green) and 579 nm (yellow-orange). These three lines can be observed superimposed on the white continuum using a hand spectroscope, for light emitted by the usual white fluorescent tubes. These same visible lines, accompanied by the emission lines of trivalent europium and trivalent terbium, and further accompanied by the emission continuum of divalent europium in the blue region, comprise the more discontinuous light emission of the modern trichromatic phosphor systems used in many compact fluorescent lamp and traditional lamps where better color rendition is a goal.

text: The common

text: fluorescent lamp

text: relies on fluorescence. Inside the

text: glass

text: tube is a partial vacuum and a small amount of

text: mercury

text: . An electric discharge in the tube causes the mercury atoms to emit mostly ultraviolet light. The tube is lined with a coating of a fluorescent material, called the

text: phosphor

text: , which absorbs the ultraviolet and re-emits visible light. Fluorescent

text: lighting

text: is more energy-efficient than

text: incandescent

text: lighting elements. However, the uneven

text: spectrum

text: of traditional fluorescent lamps may cause certain colors to appear different than when illuminated by incandescent light or

text: daylight

text: . The mercury vapor emission spectrum is dominated by a short-wave UV line at 254 nm (which provides most of the energy to the phosphors), accompanied by visible light emission at 436 nm (blue), 546 nm (green) and 579 nm (yellow-orange). These three lines can be observed superimposed on the white continuum using a hand spectroscope, for light emitted by the usual white fluorescent tubes. These same visible lines, accompanied by the emission lines of trivalent europium and trivalent terbium, and further accompanied by the emission continuum of divalent europium in the blue region, comprise the more discontinuous light emission of the modern trichromatic phosphor systems used in many

text: compact fluorescent lamp

text: and traditional lamps where better color rendition is a goal.

text: The visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range of wavelengths is called visible light or simply light. A typical human eye will respond to wavelengths from about 390 to 700 nm. In terms of frequency, this corresponds to a band in the vicinity of 430–770 THz.

text: The visible spectrum is the portion of the

text: electromagnetic spectrum

text: that is

text: visible

text: to the

text: human eye

text: Electromagnetic radiation

text: in this range of

text: wavelength

text: s is called visible light or simply

text: light

text: . A typical human eye will respond to wavelengths from about

text: 390 to 700 nm

text: . In terms of frequency, this corresponds to a band in the vicinity of 430–770

text: THz

text: Many flowering plants reflect as much light as possible within the range of visible wavelengths of the pollinator the plant intends to attract. Flowers that reflect the full range of visible light are generally perceived as white by a human observer. An important feature of white flowers is that they reflect equally across the visible spectrum. While many flowering plants use white to attract pollinators, the use of color is also widespread (even within the same species). Color allows a flowering plant to be more specific about the pollinator it seeks to attract. The color model used by human color reproduction technology (CMYK) relies on the modulation of pigments that divide the spectrum into broad areas of absorption. Flowering plants by contrast are able to shift the transition point wavelength between absorption and reflection. If it is assumed that the visual systems of most pollinators view the visible spectrum as circular then it may be said that flowering plants produce color by absorbing the light in one region of the spectrum and reflecting the light in the other region. With CMYK, color is produced as a function of the amplitude of the broad regions of absorption. Flowering plants by contrast produce color by modifying the frequency (or rather wavelength) of the light reflected. Most flowers absorb light in the blue to yellow region of the spectrum and reflect light from the green to red region of the spectrum. For many species of flowering plant, it is the transition point that characterizes the color that they produce. Color may be modulated by shifting the transition point between absorption and reflection and in this way a flowering plant may specify which pollinator it seeks to attract.

text: Many flowering plants reflect as much light as possible within the range of visible wavelengths of the pollinator the plant intends to attract. Flowers that reflect the full range of visible light are generally perceived as

text: white

text: by a human observer. An important feature of white flowers is that they reflect equally across the visible spectrum. While many flowering plants use white to attract pollinators, the use of color is also widespread (even within the same species). Color allows a flowering plant to be more specific about the pollinator it seeks to attract. The color model used by human color reproduction technology (

text: CMYK

text: ) relies on the modulation of pigments that divide the spectrum into broad areas of absorption. Flowering plants by contrast are able to shift the transition point wavelength between absorption and reflection. If it is assumed that the visual systems of most pollinators view the visible spectrum as

text: circular

text: then it may be said that flowering plants produce color by absorbing the light in one region of the spectrum and reflecting the light in the other region. With CMYK, color is produced as a function of the amplitude of the broad regions of absorption. Flowering plants by contrast produce color by modifying the frequency (or rather wavelength) of the light reflected. Most flowers absorb light in the blue to yellow region of the spectrum and reflect light from the green to red region of the spectrum. For many species of flowering plant, it is the transition point that characterizes the color that they produce. Color may be modulated by shifting the transition point between absorption and reflection and in this way a flowering plant may specify which pollinator it seeks to attract.

text: The Pistol Star is a blue hypergiant star, one of the most luminous known in the Milky Way. It is one of many massive young stars in the Quintuplet cluster in the Galactic Center region. The star owes its name to the shape of the Pistol Nebula, which it illuminates. It is located approximately 25,000 light years from Earth in the direction of Sagittarius. It would be visible to the naked eye as a fourth magnitude star if it were not for the interstellar dust that completely hides it from view in visible light.

text: The Pistol Star is a blue

text: hypergiant

text: star, one of the

text: most luminous

text: known in the

text: Milky Way

text: . It is one of many massive young stars in the

text: Quintuplet cluster

text: in the

text: Galactic Center

text: region. The star owes its name to the shape of the

text: Pistol Nebula

text: , which it illuminates. It is located approximately 25,000

text: light year

text: s from Earth in the direction of

text: Sagittarius

text: . It would be visible to the naked eye as a fourth

text: magnitude

text: star if it were not for the

text: interstellar dust

text: that completely hides it from view in visible light.

text: The Coma Supercluster contains the Coma and Leo Cluster of galaxies. The Coma Cluster, which forms Berenice's imaginary tresses, is 230 to 300 million light-years away. It is one of the largest known clusters, with at least 10,000 galaxies (mainly elliptical, with a few spiral galaxies). Due to its distance from Earth, most of the galaxies are visible only through large telescopes. Its brightest members are NGC 4889 and NGC 4874, both with a magnitude of 13; most others are magnitude 15 or dimmer. NGC 4889 is a giant elliptical galaxy with one of the largest known black holes (21 billion solar masses), and NGC 4921 is the cluster's brightest spiral galaxy. After observing the Coma Cluster, astronomer Fritz Zwicky first postulated the existence of dark matter during the 1930s. The massive galaxy Dragonfly 44 discovered in 2015 was found to consist almost entirely of dark matter. Its mass is very similar to that of the Milky Way.

text: The

text: Coma Supercluster

text: contains the

text: Coma

text: and

text: Leo Cluster

text: of galaxies. The Coma Cluster, which forms Berenice's imaginary tresses, is 230 to 300 million light-years away. It is one of the largest known clusters, with at least 10,000 galaxies (mainly

text: elliptical

text: , with a few

text: spiral galaxies

text: ). Due to its distance from Earth, most of the galaxies are visible only through large telescopes. Its brightest members are

text: NGC 4889

text: and

text: NGC 4874

text: , both with a magnitude of 13; most others are magnitude 15 or dimmer. NGC 4889 is a giant elliptical galaxy with one of the largest known

text: black hole

text: s (21 billion

text: solar mass

text: es), and

text: NGC 4921

text: is the cluster's brightest spiral galaxy. After observing the Coma Cluster, astronomer

text: Fritz Zwicky

text: first postulated the existence of

text: dark matter

text: during the 1930s. The massive galaxy

text: Dragonfly 44

text: discovered in 2015 was found to consist almost entirely of dark matter. Its mass is very similar to that of the

text: Milky Way

text: Naphthalocyanines (NCs) are an extended PC derivative. They have an additional benzene ring attached to each isoindole sub-unit on the periphery of the PC structure. Subsequently, NCs absorb strongly at even longer wavelengths (approximately 740–780 nm) than PCs (670–780 nm). This absorption in the near infrared region makes NCs candidates for highly pigmented tumours, including melanomas, which present significant absorption problems for visible light.

text: Naphthalocyanines (NCs) are an extended PC derivative. They have an additional benzene ring attached to each

text: isoindole

text: sub-unit on the periphery of the PC structure. Subsequently, NCs absorb strongly at even longer wavelengths (approximately 740–780 nm) than PCs (670–780 nm). This absorption in the near infrared region makes NCs candidates for highly pigmented tumours, including melanomas, which present significant absorption problems for visible light.

text: Since LCD panels produce no light of their own, they require external light to produce a visible image. In a "transmissive" type of LCD, this light is provided at the back of the glass "stack" and is called the backlight. While passive-matrix displays are usually not backlit (e.g. calculators, wristwatches), active-matrix displays almost always are.

text: In 1999, Danish physicist Lene Hau led a team from Harvard University which slowed a beam of light to about 17 meters per second., using a superfluid. Hau and her associates have since made a group of condensate atoms recoil from a light pulse such that they recorded the light's phase and amplitude, recovered by a second nearby condensate, in what they term "slow-light-mediated atomic matter-wave amplification" using Bose–Einstein condensates: details are discussed in Nature.

text: In 1999, Danish physicist

text: Lene Hau

text: led a team from

text: Harvard University

text: which

text: slowed a beam of light

text: to about 17 meters per second., using a superfluid. Hau and her associates have since made a group of condensate atoms recoil from a light pulse such that they recorded the light's phase and amplitude, recovered by a second nearby condensate, in what they term "slow-light-mediated atomic matter-wave amplification" using Bose–Einstein condensates: details are discussed in

text: Nature

text: The modern conception of matter has been refined many times in history, in light of the improvement in knowledge of just what the basic building blocks are, and in how they interact.The term "matter" is used throughout physics in a bewildering variety of contexts: for example, one refers to "condensed matter physics", "elementary matter", "partonic" matter, "dark" matter, "anti"-matter, "strange" matter, and "nuclear" matter. In discussions of matter and antimatter, normal matter has been referred to by Alfvén as koinomatter (Gk. common matter). It is fair to say that in physics, there is no broad consensus as to a general definition of matter, and the term "matter" usually is used in conjunction with a specifying modifier.

text: The modern conception of matter has been refined many times in history, in light of the improvement in knowledge of just what the basic building blocks are, and in how they interact.The term "matter" is used throughout physics in a bewildering variety of contexts: for example, one refers to "

text: condensed matter physics

text: ", "elementary matter", "

text: partonic

text: " matter, "

text: dark

text: " matter, "

text: anti

text: "-matter, "

text: strange

text: " matter, and "

text: nuclear

text: " matter. In discussions of matter and

text: antimatter

text: , normal matter has been referred to by

text: Alfvén

text: as koinomatter (Gk. common matter). It is fair to say that in

text: physics

text: , there is no broad consensus as to a general definition of matter, and the term "matter" usually is used in conjunction with a specifying modifier.

text: In 1913, the year in which Niels Bohr introduced the Bohr model of the atom, Kossel went to the University of Munich as assistant to Arnold Sommerfeld, under whom he did his Habilitation.  Under Sommerfeld, Munich was a theoretical center for the developing atomic theory, especially from the interpretation of atomic spectra.  In 1916, Kossel put forth his theory of the ionic chemical bond (octet rule), also independently advanced in the same year by Gilbert N. Lewis.  In papers published in 1914, 1916, and 1920, Kossel was the first to explain the theory of absorption limits in x-ray spectra.  The edge appears at a critical frequency where absorption of the radiation largely begins with the resultant ejection of photoelectrons.  In 1919, Kossel and Sommerfeld explained the similarity of the atomic spectra of neutral atoms, of atomic number Z, and singly ionized atoms, of atomic number Z + 1, which became known as the Sommerfeld–Kossel displacement law.  In 1920, Kossel explained another phenomenon of x-ray spectra.  Under high resolution spectroscopy, the absorption edge has structure.  He attributed this to absorption of radiation by electrons which are not ejected from matter as photoelectrons, but are “kicked up” to higher, unoccupied, bound electron energy levels.  In early years, this was known as “Kossel structure.”

text: In 1913, the year in which

text: Niels Bohr

text: introduced the

text: Bohr model

text: of the atom, Kossel went to the

text: University of Munich

text: as assistant to

text: Arnold Sommerfeld

text: , under whom he did his

text: Habilitation

text: .  Under Sommerfeld, Munich was a theoretical center for the developing

text: atomic theory

text: , especially from the interpretation of

text: atomic spectra

text: .  In 1916, Kossel put forth his theory of the

text: ionic chemical bond

text: octet rule

text: ), also independently advanced in the same year by

text: Gilbert N. Lewis

text: .  In papers published in 1914, 1916, and 1920, Kossel was the first to explain the theory of absorption limits in

text: x-ray spectra

text: .  The edge appears at a critical frequency where absorption of the radiation largely begins with the resultant ejection of

text: photoelectrons

text: .  In 1919, Kossel and Sommerfeld explained the similarity of the

text: atomic spectra

text: of neutral atoms, of

text: atomic number

text: Z, and singly ionized atoms, of atomic number Z + 1, which became known as the

text: Sommerfeld–Kossel displacement law

text: .  In 1920, Kossel explained another phenomenon of x-ray spectra.  Under high resolution spectroscopy, the absorption edge has structure.  He attributed this to absorption of radiation by electrons which are not ejected from matter as photoelectrons, but are “kicked up” to higher, unoccupied, bound electron energy levels.  In early years, this was known as “

text: Kossel structure

text: In cosmology, baryon acoustic oscillations (BAO) are regular, periodic fluctuations in the density of the visible baryonic matter (normal matter) of the universe.  In the same way that supernova provide a "standard candle" for astronomical observations, BAO matter clustering provides a "standard ruler" for length scale in cosmology.  The length of this standard ruler (~490 million light years in today's universe) can be measured by looking at the large scale structure of matter using astronomical surveys.  BAO measurements help cosmologists understand more about the nature of dark energy (which causes the apparent slight acceleration of the expansion of the universe) by constraining cosmological parameters.

text: In

text: cosmology

text: , baryon acoustic oscillations (BAO) are regular, periodic fluctuations in the density of the visible

text: baryonic

text: matter (normal matter) of the universe.  In the same way that

text: supernova

text: provide a "

text: standard candle

text: " for astronomical observations, BAO matter clustering provides a "

text: standard ruler

text: " for length scale in cosmology.  The length of this standard ruler (~490 million light years in today's universe) can be measured by looking at the

text: large scale structure

text: of matter using

text: astronomical survey

text: s.  BAO measurements help cosmologists understand more about the nature of

text: dark energy

text: (which causes the apparent slight acceleration of the expansion of the universe) by constraining

text: cosmological parameters

text: The appearance and perception of a tooth is the result of a complex interaction of factors such as lighting conditions, translucency, opacity, light scattering, gloss and the human eye and brain. Of these, the intrinsic pigmentation of a tooth is the most influential, which in turn is determined by genetic and natural factors. Light hitting a tooth undergoes reflection, absorption and transmission by varying degrees in each tissue layer of the tooth substance. Reflected light detected by the human eye determines the perceived appearance of a tooth.

text: The appearance and perception of a tooth is the result of a complex interaction of factors such as lighting conditions,

text: translucency

text: opacity

text: light scattering

text: gloss

text: and the human eye and brain. Of these, the intrinsic pigmentation of a tooth is the most influential, which in turn is determined by genetic and natural factors. Light hitting a tooth undergoes

text: reflection

text: absorption

text: and transmission by varying degrees in each tissue layer of the tooth substance. Reflected light detected by the human eye determines the perceived appearance of a tooth.

text: These are by far the most common type of hologram - and in fact they are not holograms in any true sense of the words. The term "hologram" has taken on a secondary meaning due to the widespread use of a multilayer image on credit cards and driver licenses. This type of "hologram" consists of two or more images stacked in such a way that each is alternately visible depending upon the angle of perspective of the viewer. The technology here is similar to the technology used for the past 50 years to make red safety night reflectors for bicycles, trucks, and cars. These holograms (and therefore the artwork of these holograms) may be of two layers (i.e. with a background and a foreground) or three layers (with a background, a middle ground and a foreground). In the case of the two-layer holograms, the matter of the middle ground is usually superimposed over the matter of the background of the hologram. These holograms display a unique multilevel, multi-colour effect. These images have one or two levels of flat graphics “floating” above or at the surface of the hologram. The matter in the background appears to be under or behind the hologram, giving the illusion of depth.

text: Nuclear weapons emit large amounts of thermal radiation as visible, infrared, and ultraviolet light, to which the atmosphere is largely transparent. This is known as "Flash". The chief hazards are burns and eye injuries. On clear days, these injuries can occur well beyond blast ranges, depending on weapon yield. Fires may also be started by the initial thermal radiation, but the following high winds due to the blast wave may put out almost all such fires, unless the yield is very high, where the range of thermal effects vastly out ranges blast effects, as observed from explosions in the multi-megaton range.  This is because the intensity of the blast effects drops off with the third power of distance from the explosion, while the intensity of radiation effects drops off with the second power of distance. This results in the range of thermal effects increasing markedly more than blast range as higher and higher device yields are detonated. Thermal radiation accounts for between 35-45% of the energy released in the explosion, depending on the yield of the device. In urban areas, the extinguishing of fires ignited by thermal radiation may matter little, as in a surprise attack fires may also be started by blast-effect-induced electrical shorts, gas pilot lights, overturned stoves, and other ignition sources, as was the case in the breakfast-time bombing of Hiroshima. Whether or not these secondary fires will in turn themselves be snuffed out as modern noncombustible brick and concrete buildings collapse in on themselves from the same blast wave is uncertain, not least of which, because of the masking effect of modern city landscapes on thermal and blast transmission are continually examined. When combustible frame buildings were blown down in Hiroshima and Nagasaki, they did not burn as rapidly as they would have done had they remained standing. The noncombustible debris produced by the blast frequently covered and prevented the burning of combustible material.Fire experts suggest that unlike Hiroshima, due to the nature of modern U.S. city design and construction, a firestorm in modern times is unlikely after a nuclear detonation. This does not exclude fires from being started, but means that these fires will not form into a firestorm, due largely to the differences between modern building materials and that used in World War II era Hiroshima.

text: Nuclear weapons emit large amounts of

text: thermal radiation

entity_name: Atomic bombings of Hiroshima and Nagasaki

text: bombing of Hiroshima

text: . Whether or not these secondary fires will in turn themselves be snuffed out as modern noncombustible brick and concrete buildings collapse in on themselves from the same blast wave is uncertain, not least of which, because of the masking effect of modern city landscapes on thermal and blast transmission are continually examined. When combustible frame buildings were blown down in Hiroshima and Nagasaki, they did not burn as rapidly as they would have done had they remained standing. The noncombustible debris produced by the blast frequently covered and prevented the burning of combustible material.Fire experts suggest that unlike Hiroshima, due to the nature of modern U.S. city design and construction, a firestorm in modern times is unlikely after a nuclear detonation. This does not exclude fires from being started, but means that these fires will not form into a

text: firestorm

text: , due largely to the differences between modern building materials and that used in World War II era Hiroshima.

text: The full quantum description of matter-light interaction is given by the Jaynes-Cummings model. The three terms of the Jaynes-Cummings model can be ascribed to a cavity term, which is mimicked by a harmonic oscillator, an atomic term and an interaction term.

text: The full quantum description of matter-light interaction is given by the

text: Jaynes-Cummings model

text: . The three terms of the Jaynes-Cummings model can be ascribed to a cavity term, which is mimicked by a harmonic oscillator, an atomic term and an interaction term.

text: For a body to be rendered inertialess, in principle, its mass should be reduced to zero. In classical special and general relativity, massless bodies are constrained to always move at exactly the speed of light (the speed of photons in a vacuum), and the term relativity in this context in fact implies that light is always measured to move at the same speed by an observer, no matter how rapidly the observer is moving relative to any body defined as fixed. This aspect of inertialessness is explored by the more exacting authors who have adopted the term after Smith's groundbreaking use.

text: For a body to be rendered inertialess, in principle, its mass should be reduced to zero. In classical

text: special

text: and

text: general relativity

text: , massless bodies are constrained to always move at exactly the

text: speed of light

text: (the speed of photons in a vacuum), and the term relativity in this context in fact implies that light is always measured to move at the same speed by an observer, no matter how rapidly the observer is moving relative to any body defined as fixed. This aspect of inertialessness is explored by the more exacting authors who have adopted the term after Smith's groundbreaking use.

text: The prism in a Herschel wedge is a trapezoidal cross section. The surface of the prism facing the light acts the same as a standard diagonal mirror reflecting a small portion of the incoming light at 90 degrees into the eyepiece. The trapezoidal prism shape refracts the remainder light gathered by the telescope's the objective away at an angle. The Herschel Wedge reflects about 4.6% of the light that passes through one of the prism faces that is flat to 1/10 of a wave. 95.4% of light and heat goes into the prism and exits through the other face and out the backdoor of the housing, thus the excess light and heat is dispensed and not used for observing. While they decrease the intensity of the light, they do not affect the visible spectra, resulting in a more accurate spectral profile which can be filtered to bring out certain details. They are an alternative to white light filters, which, despite their name, inherently must block certain visible spectra.

text: The prism in a Herschel wedge is a trapezoidal cross section. The surface of the prism facing the light acts the same as a standard

text: diagonal mirror

text: reflecting a small portion of the incoming light at 90 degrees into the eyepiece. The trapezoidal prism shape refracts the remainder light gathered by the telescope's the

text: objective

text: away at an angle. The Herschel Wedge reflects about 4.6% of the light that passes through one of the prism faces that is flat to 1/10 of a wave. 95.4% of light and heat goes into the prism and exits through the other face and out the backdoor of the housing, thus the excess light and heat is dispensed and not used for observing. While they decrease the intensity of the light, they do not affect the visible spectra, resulting in a more accurate spectral profile which can be filtered to bring out certain details. They are an alternative to white light filters, which, despite their name, inherently must block certain visible spectra.

text: The black level of a single-chip DLP depends on how unused light is being disposed. If the unused light is scattered to reflect and dissipate on the rough interior walls of the DMD / lens chamber, this scattered light will be visible as a dim gray on the projection screen, when the image is fully dark. Deeper blacks and higher contrast ratios are possible by directing unused HID light away from the DMD / lens chamber into a separate area for dissipation, and shielding the light path from unwanted internal secondary reflections.

text: The

text: black level

text: of a single-chip DLP depends on how unused light is being disposed. If the unused light is scattered to reflect and dissipate on the rough interior walls of the DMD / lens chamber, this scattered light will be visible as a dim gray on the projection screen, when the image is fully dark. Deeper blacks and higher contrast ratios are possible by directing unused HID light away from the DMD / lens chamber into a separate area for dissipation, and shielding the light path from unwanted internal secondary reflections.

text: The fluorescent lamp first became common in the late 1930s. These lamps are a form of discharge lamp where a small current causes a gas in the tube to glow. The typical glow is strong in ultraviolet but weak in visible light. The glass envelope is coated in a mixture of phosphors that are excited by the ultraviolet light and emit visible light. Fluorescent lamps are much more efficient than incandescent lamps, and for a short time became popular in street lighting both because of the efficiency and the novelty value. Fluorescent lamps for street lighting were first introduced to the public for commercial uses at the 1939 World's Fair.

text: The

text: fluorescent lamp

text: first became common in the late 1930s. These lamps are a form of

text: discharge lamp

text: where a small current causes a gas in the tube to glow. The typical glow is strong in ultraviolet but weak in visible light. The glass envelope is coated in a mixture of phosphors that are excited by the ultraviolet light and emit visible light. Fluorescent lamps are much more efficient than incandescent lamps, and for a short time became popular in street lighting both because of the efficiency and the novelty value. Fluorescent lamps for street lighting were first introduced to the public for commercial uses at the

text: 1939 World's Fair

text: The artifacts are especially common with compact or ultra-compact cameras, where the short distance between the lens and the built-in flash decreases the angle of light reflection to the lens, directly illuminating the aspect of the particles facing the lens and increasing the camera's ability to capture the light reflected off normally sub-visible particles.

text: The artifacts are especially common with compact or ultra-compact cameras, where the short distance between the lens and the built-in flash decreases the angle of light

text: reflection

text: to the lens, directly illuminating the aspect of the particles facing the lens and increasing the camera's ability to capture the light reflected off normally sub-visible particles.

text: Retro-reflective materials, in the form of fixed reflectors, reflective tape, and reflective clothing, are useful in making a cyclist visible to other road users.  Reflective materials can be applied to bike, rider, or luggage; also, tyres are available with reflective sidewalls. Reflectives are visible only when in the beam of a headlight, and even then only within a narrow locus.  Importantly, they do nothing to light up the road. Reflectors are not a substitute for lights, but are an important supplement to portable lighting.

text: Retro-reflective materials

text: , in the form of fixed reflectors, reflective tape, and reflective clothing, are useful in making a cyclist visible to other road users.  Reflective materials can be applied to bike, rider, or luggage; also, tyres are available with reflective sidewalls. Reflectives are visible only when in the beam of a headlight, and even then only within a narrow locus.  Importantly, they do nothing to light up the road. Reflectors are not a substitute for lights, but are an important supplement to portable lighting.

text: Optical or light microscopy involves passing visible light transmitted through or reflected from the sample through a single or multiple lenses to allow a magnified view of the sample. The resulting image can be detected directly by the eye, imaged on a photographic plate or captured digitally. The single lens with its attachments, or the system of lenses and imaging equipment, along with the appropriate lighting equipment, sample stage and support, makes up the basic light microscope. The most recent development is the digital microscope, which uses a CCD camera to focus on the exhibit of interest. The image is shown on a computer screen, so eye-pieces are unnecessary.

text: Optical or light microscopy involves passing

text: visible light

text: transmitted through or reflected from the sample through a single or multiple

text: lenses

text: to allow a magnified view of the sample. The resulting image can be detected directly by the eye, imaged on a

text: photographic plate

text: or

text: captured digitally

text: . The single lens with its attachments, or the system of lenses and imaging equipment, along with the appropriate lighting equipment, sample stage and support, makes up the basic light microscope. The most recent development is the

text: digital microscope

text: , which uses a

text: CCD camera

text: to focus on the exhibit of interest. The image is shown on a computer screen, so eye-pieces are unnecessary.

text: The observatory was established in 1958, and its largest telescope, the Nicholas Mayall 4m was dedicated in 1973. The Mayall played a key role in the discovery of dark matter though observations of external galaxies which showed that the galaxies rotated faster than they should have if the motion were due only to the mass in stars seen in visible light images.

text: The observatory was established in 1958, and its largest telescope, the Nicholas Mayall 4m was dedicated in 1973. The Mayall played a key role in the discovery of

text: dark matter

text: though observations of external galaxies which showed that the galaxies rotated faster than they should have if the motion were due only to the mass in stars seen in visible light images.

text: MODTRAN (MODerate resolution atmospheric TRANsmission) is a computer program designed to model atmospheric propagation of electromagnetic radiation for the 100-50,000 cm (0.2 to 100 um) spectral range.  This covers the spectrum from middle ultraviolet to visible light to far infrared.

text: MODTRAN (MODerate resolution atmospheric TRANsmission) is a computer program designed to model

text: atmospheric

text: propagation of

text: electromagnetic radiation

text: for the 100-50,000 cm (0.2 to 100 um) spectral range.  This covers the spectrum from middle

text: ultraviolet

text: to

text: visible light

text: to

text: far infrared

text: Above the range of visible light, ultraviolet light becomes invisible to humans, mostly because it is absorbed by the cornea below 360 nanometers and the internal lens below 400. Furthermore, the rods and cones located in the retina of the human eye cannot detect the very short (below 360 nm) ultraviolet wavelengths and are in fact damaged by ultraviolet.  Many animals with eyes that do not require lenses (such as insects and shrimp) are able to detect ultraviolet, by quantum photon-absorption mechanisms, in much the same chemical way that humans detect visible light.

text: Above the range of visible light, ultraviolet light becomes invisible to humans, mostly because it is absorbed by the cornea below 360 nanometers and the internal lens below 400. Furthermore, the

text: rods

text: and

text: cones

text: located in the

text: retina

text: of the human eye cannot detect the very short (below 360 nm) ultraviolet wavelengths and are in fact damaged by ultraviolet.  Many animals with eyes that do not require lenses (such as insects and shrimp) are able to detect ultraviolet, by quantum photon-absorption mechanisms, in much the same chemical way that humans detect visible light.

text: materials (organic photovoltaics, OPVs) that allow visible light to pass through its technology but selectively absorb the light from the invisible part of the spectrum, near infrared (NIR) and ultraviolet (UV) light.  They call this technology ClearView power .  ClearView Power  is an invisible film less than 1/100th of a millimeter thick that can be put onto any surface and generate energy without with out affecting the material beneath it.  Specifically they are trying to capture all of the photons of ultraviolet and infrared light while allowing the photons of visible light to pass through. Once energy is created from the OPVs, it is able to be harvested through dye-sensitized solar cells (DSC) containing electrodes as electron emitters and iodide/tri-iodide redox electrolyte as an entire transport layer.

text: materials (organic

text: photovoltaics

text: , OPVs) that allow visible light to pass through its technology but selectively absorb the light from the invisible part of the spectrum, near infrared (NIR) and ultraviolet (UV) light.  They call this technology ClearView power .  ClearView Power  is an invisible film less than 1/100th of a millimeter thick that can be put onto any surface and generate energy without with out affecting the material beneath it.  Specifically they are trying to capture all of the

text: photon

text: s of ultraviolet and infrared light while allowing the photons of visible light to pass through. Once energy is created from the OPVs, it is able to be harvested through dye-sensitized solar cells (DSC) containing electrodes as electron emitters and iodide/tri-iodide redox electrolyte as an entire transport layer.

text: Under the Tyndall effect, the longer-wavelength light is more transmitted while the shorter-wavelength light is more reflected via scattering. An analogy to this wavelength dependency is that longwave electromagnetic waves such as radio waves are able to pass through the walls of buildings, while shortwave electromagnetic waves such as light waves are stopped and reflected by the walls. The Tyndall effect is seen when light-scattering particulate-matter is dispersed in an otherwise-light-transmitting medium, when the cross-section of an individual particulate is the range of roughly between 40 and 900 nanometers, i.e., somewhat below or near the wavelength of visible light (400–750 nanometers).

text: Under the Tyndall effect, the longer-wavelength light is more

text: transmitted

text: while the shorter-wavelength light is more

text: reflected via scattering

text: . An analogy to this wavelength dependency is that longwave electromagnetic waves such as radio waves are able to pass through the walls of buildings, while shortwave electromagnetic waves such as light waves are stopped and reflected by the walls. The Tyndall effect is seen when light-scattering particulate-matter is dispersed in an otherwise-light-transmitting medium, when the cross-section of an individual

text: particulate

text: is the range of roughly between 40 and 900 nanometers, i.e., somewhat below or near the wavelength of visible light (400–750 nanometers).

text: Ray-Ban polarized sunglasses have the transmission axis oriented vertically to block reflecting light. Polarized lenses are also appropriate for indoor use and can be worn by people whose eyes are light-sensitive; including post-cataract surgery patients and those continually exposed to bright light through windows. They may reduce the visibility of images produced by liquid crystal displays (LCDs) found on the dashboards of some cars or in other places such as the digital screens on automatic teller (bank) machines.

text: Ray-Ban polarized sunglasses have the transmission axis oriented vertically to block reflecting light. Polarized lenses are also appropriate for indoor use and can be worn by people whose eyes are

text: light-sensitive

text: ; including post-

text: cataract surgery

text: patients and those continually exposed to bright light through windows. They may reduce the visibility of images produced by liquid crystal displays (LCDs) found on the dashboards of some cars or in other places such as the digital screens on automatic teller (bank) machines.

text: Infrared (IR) spectroscopy by ATR is applicable to the same chemical or biological systems as the transmission method. One advantage of ATR-IR over transmission-IR, is the limited path length into the sample. This avoids the problem of strong attenuation of the IR signal in highly absorbing media, such as aqueous solutions. For ultraviolet or visible light (UV/Vis) the evanescent light path gets short so that interaction with the sample is decreased with wavelength. For optically dense samples, this may allow for measurements with UV. Also, as no light path has to be established single shaft probes are used for process monitoring and are applicable in both the near and mid infrared spectrum.

text: The reflection is caused by the coherent strong interaction of the neutron with atomic nuclei. It can be quantum-mechanically described by an effective potential which is commonly referred to as the Fermi pseudo potential or the neutron optical potential. The corresponding velocity is called the critical velocity of a material. Neutrons are reflected from a surface if the velocity component normal to the reflecting surface is less or equal the critical velocity.

text: The reflection is caused by the coherent

text: strong interaction

text: of the neutron with atomic nuclei. It can be quantum-mechanically described by an effective potential which is commonly referred to as the

text: Fermi

text: pseudo potential or the neutron optical potential. The corresponding velocity is called the critical velocity of a material. Neutrons are reflected from a surface if the velocity component normal to the reflecting surface is less or equal the critical velocity.

text: Despite its invisible interior, the presence of a black hole can be inferred through its interaction with other matter and with electromagnetic radiation such as visible light. Matter that falls onto a black hole can form an external accretion disk heated by friction, forming some of the brightest objects in the universe. If there are other stars orbiting a black hole, their orbits can be used to determine the black hole's  mass and location. Such observations can be used to exclude possible alternatives such as neutron stars. In this way, astronomers have identified numerous stellar black hole candidates in binary systems, and established that the radio source known as Sagittarius A*, at the core of our own Milky Way galaxy, contains a supermassive black hole of about 4.3 million solar masses.

text: Despite its invisible interior, the presence of a black hole can be inferred through its interaction with other

text: matter

text: and with

text: electromagnetic radiation

text: such as visible light. Matter that falls onto a black hole can form an external

text: accretion disk

text: heated by friction, forming some of the

text: brightest objects in the universe

text: . If there are other stars orbiting a black hole, their orbits can be used to determine the black hole's  mass and location. Such observations can be used to exclude possible alternatives such as neutron stars. In this way, astronomers have identified numerous stellar black hole candidates in

text: binary systems

text: , and established that the radio source known as

text: Sagittarius A*

text: , at the core of our own

text: Milky Way

text: galaxy, contains a supermassive black hole of about 4.3 million

text: solar mass

text: es.

text: For most substances, absorptions in the visible spectrum are usually attributed to excitations of electronic energy states. However, water is a simple 3-atom molecule, HO, and all its electronic absorptions occur in the ultraviolet region of the electromagnetic spectrum and are therefore not responsible for the color of water in the visible region of the spectrum. Nevertheless, the water molecule has three fundamental modes of vibration, including two stretching vibrations of the O-H bonds which occur at v = 3650 cm and v = 3755 cm. Absorption due to these vibrations occurs in the infrared region of the spectrum. The absorption in the visible spectrum is due mainly to the harmonic v + 3v  = 14,318 cm, which is equivalent to a wavelength of 698 nm.

text: For most substances, absorptions in the visible spectrum are usually attributed to excitations of

text: electronic

text: energy states. However, water is a simple 3-atom

text: molecule

text: , HO, and all its electronic absorptions occur in the

text: ultraviolet

text: region of the

text: electromagnetic spectrum

text: and are therefore not responsible for the color of water in the visible region of the spectrum. Nevertheless, the water molecule has three fundamental modes of

text: vibration

text: , including two stretching vibrations of the O-H

text: bond

text: s which occur at v = 3650 cm and v = 3755 cm. Absorption due to these vibrations occurs in the

text: infrared

text: region of the spectrum. The absorption in the visible spectrum is due mainly to the

text: harmonic

text: v + 3v  = 14,318 cm, which is equivalent to a wavelength of 698 nm.

text: Infrared radiation is popularly known as "heat radiation", but light and electromagnetic waves of any frequency will heat surfaces that absorb them. Infrared light from the Sun accounts for 49% of the heating of Earth, with the rest being caused by visible light that is absorbed then re-radiated at longer wavelengths. Visible light or ultraviolet-emitting lasers can char paper and incandescently hot objects emit visible radiation. Objects at room temperature will emit radiation concentrated mostly in the 8 to 25 µm band, but this is not distinct from the emission of visible light by incandescent objects and ultraviolet by even hotter objects (see black body and Wien's displacement law).

text: Infrared radiation is popularly known as "heat radiation", but light and electromagnetic waves of any frequency will heat surfaces that absorb them. Infrared light from the Sun accounts for 49% of the heating of Earth, with the rest being caused by visible light that is absorbed then re-radiated at longer wavelengths. Visible light or

text: ultraviolet

text: -emitting

text: laser

text: s can char paper and incandescently hot objects emit visible radiation. Objects at room

text: temperature

text: will

text: emit

text: radiation

text: concentrated mostly in the 8 to 25 µm band, but this is not distinct from the emission of visible light by incandescent objects and ultraviolet by even hotter objects (see

text: black body

text: and

text: Wien's displacement law

text: Today, on most modern aircraft the swashplate is above the transmission and the pushrods are visible outside the fuselage, but a few early designs, notably light helicopters built by Enstrom Helicopter, placed it underneath the transmission and enclosed the rotating pushrods inside the mainshaft.  This reduces rotor hub drag since there are no exposed linkages.

text: Today, on most modern aircraft the swashplate is above the transmission and the pushrods are visible outside the fuselage, but a few early designs, notably light helicopters built by

text: Enstrom Helicopter

text: , placed it underneath the transmission and enclosed the rotating pushrods inside the mainshaft.  This reduces rotor hub drag since there are no exposed linkages.

text: As Snake pilots the glider into the city, there are three screens on his control panel displaying wireframe animations of the landing target on the World Trade Center and surrounding buildings. What appears on those screens was not computer-generated. Carpenter wanted high-tech computer graphics which were very expensive at the time, even for such a simple animation. To get the animation he wanted, the effects crew filmed the miniature model set of New York City they used for other scenes under black light with reflective tape placed along every edge of the model buildings. Only the tape is visible and appears to be a 3D wireframe animation.

text: As Snake pilots the glider into the city, there are three screens on his control panel displaying

text: wireframe

text: animations of the landing target on the

text: World Trade Center

text: and surrounding buildings. What appears on those screens was not computer-generated. Carpenter wanted high-tech computer graphics which were very expensive at the time, even for such a simple animation. To get the animation he wanted, the effects crew filmed the miniature model set of New York City they used for other scenes under

text: black light

text: with reflective tape placed along every edge of the model buildings. Only the tape is visible and appears to be a 3D wireframe animation.

text: Approximately two to three hours before the visible light from SN 1987A reached Earth, a burst of neutrinos was observed at three separate neutrino observatories. This is likely due to neutrino emission, which occurs simultaneously with core collapse, but preceding the emission of visible light. Transmission of visible light is a slower process that occurs only after the shock wave reaches the stellar surface.At 07:35 UT, Kamiokande II detected 12 antineutrinos; IMB, 8 antineutrinos; and Baksan, 5 antineutrinos; in a burst lasting less than 13 seconds. Approximately three hours earlier, the Mont Blanc liquid scintillator detected a five-neutrino burst, but this is generally not believed to be associated with SN 1987A.

text: Approximately two to three hours before the visible light from SN 1987A reached Earth, a burst of

text: neutrino

text: s was observed at three separate

text: neutrino observatories

text: . This is likely due to neutrino emission, which occurs simultaneously with core collapse, but preceding the emission of visible light. Transmission of visible light is a slower process that occurs only after the shock wave reaches the stellar surface.At 07:35

text: UT

text: Kamiokande II

text: detected 12

text: antineutrino

text: s;

text: IMB

text: , 8 antineutrinos; and

text: Baksan

text: , 5 antineutrinos; in a burst lasting less than 13 seconds. Approximately three hours earlier, the

text: Mont Blanc

text: liquid scintillator

text: detected a five-neutrino burst, but this is generally not believed to be associated with SN 1987A.

text: Incomplete trajectories, or evolutionary pathways, are shown to be caused by T52F mutations occurring first because T52F does not have a peak for the absorption of light within the entire visible region. T52F mutations are deemed to be structurally unstable, and the evolutionary path is immediately terminated. Having any of the other stable mutations occur first, including F46T, F49L, F86L, T93P, A114G or S118T, opens up the possibility of having 1032 out of 5042 potential trajectories open up to evolution. This is because having any of the other mutations occur first would allow for 134, 74, 252, 348, 102 and 122 potential pathways for mutations involving each of the remaining 6 mutants, equal to 1032 potential pathways for the evolution of short wavelength sensitive opsins to take place.

text: Absorption can facilitate the experience of both positive and negative emotions. Positive experiences facilitated by absorption include the enjoyment of music, art, and natural beauty (e.g. sunsets) and pleasant forms of daydreaming. Absorption has also been linked to forms of maladjustment, such as nightmare frequency and anxiety sensitivity (fear of one's own anxiety symptoms), and dissociative symptoms. Absorption may act to amplify minor somatic symptoms, leading to an increased risk of conditions associated with hypersensitivity to internal bodily sensations, such as somatoform disorders and panic disorder. People may have a particular risk of the aforementioned problems when they are prone to both  high absorption and to personality traits associated with negative emotionality.

text: Absorption can facilitate the experience of both positive and negative emotions. Positive experiences facilitated by absorption include the enjoyment of music, art, and natural beauty (e.g. sunsets) and pleasant forms of

text: daydreaming

text: . Absorption has also been linked to forms of maladjustment, such as

text: nightmare

text: frequency and anxiety sensitivity (fear of one's own anxiety symptoms), and

text: dissociative

text: symptoms. Absorption may act to amplify minor somatic symptoms, leading to an increased risk of conditions associated with hypersensitivity to internal bodily sensations, such as

text: somatoform disorders

text: and

text: panic disorder

text: . People may have a particular risk of the aforementioned problems when they are prone to both  high absorption and to personality traits associated with negative emotionality.

text: Heat rejection films are normally applied to the interior of flat glass windows to reduce the amount of infrared, visible light, and ultraviolet (UV) radiation entering windows. Such films are usually dyed or metalized (which can be transparent to visible light) to convert incoming solar radiation to infrared radiation, which is then rejected back through the glass to the exterior. Modern window film technology has created ceramic window films which are non-metallic and do not contain dyes that can result in discoloration. The ceramic and metallic window films usually cost 10–15 percent more than regular window film but can reduce energy transmission by as much as 80 percent.  Ceramic window films cost slightly more but provide a substantial increase in blocking UV rays and ability to control heat transfer.

text: Heat rejection films are normally applied to the interior of flat glass windows to reduce the amount of

text: infrared

text: visible light

text: , and

text: ultraviolet

text: (UV)

text: radiation

text: entering windows. Such films are usually dyed or metalized (which can be transparent to visible light) to convert incoming

text: solar radiation

text: to infrared radiation, which is then rejected back through the glass to the exterior. Modern window film technology has created ceramic window films which are non-metallic and do not contain dyes that can result in discoloration. The ceramic and metallic window films usually cost 10–15 percent more than regular window film but can reduce energy transmission by as much as 80 percent.  Ceramic window films cost slightly more but provide a substantial increase in blocking UV rays and ability to control heat transfer.

text: Electromagnetic radiation (EM radiation or EMR) is the radiant energy released by certain electromagnetic processes. Visible light is electromagnetic radiation, as is invisible light, such as radio, infrared, and X-rays.

text: Electromagnetic radiation (EM radiation or EMR) is the radiant energy released by certain

text: electromagnetic

text: processes.

text: Visible light

text: is electromagnetic radiation, as is invisible light, such as

text: radio

text: infrared

text: , and

text: X-rays

text: The JWST's primary scientific mission has four key goals: to search for light from the first stars and galaxies that formed in the Universe after the Big Bang, to study the formation and evolution of galaxies, to understand the formation of stars and planetary systems and to study planetary systems and the origins of life. These goals can be accomplished more effectively by observation in near-infrared light rather than light in the visible part of the spectrum. For this reason the JWST's instruments will not measure visible or ultraviolet light like the Hubble Telescope, but will have a much greater capacity to perform infrared astronomy. The JWST will be sensitive to a range of wavelengths from 0.6 (orange light) to 28 micrometers (deep infrared radiation at about ).

text: The JWST's primary scientific mission has four key goals: to search for

text: light

text: from the first

text: star

text: s and

text: galaxies

text: that formed in the

text: Universe

text: after the

text: Big Bang

text: , to study the

text: formation and evolution of galaxies

text: , to understand the

text: formation of stars

text: and

text: planetary systems

text: and to study

text: planetary system

text: s and the

text: origins of life

text: . These goals can be accomplished more effectively by observation in near-infrared light rather than light in the visible part of the spectrum. For this reason the JWST's instruments will not measure visible or ultraviolet light like the Hubble Telescope, but will have a much greater capacity to perform

text: infrared astronomy

text: . The JWST will be sensitive to a range of wavelengths from 0.6 (orange light) to 28

text: micrometers

text: (deep infrared radiation at about ).

text: Within this universe, all matter is made up of two competing forces: order and chaos.  In their natural state, these forces are equally matched, in a condition called Balance.  These two forces can be seen as fantasy representations of the natural entropy (chaos) that occurs in matter, balanced by the various molecular forces (order) that bind matter into structured forms.  These forces are understood, at a basic level, by all inhabitants of the world.  The colour white is identified with chaos; black with order.  The first published novel explains it this way: white is the chaotic combination of all wavelengths of visible light, while black is the absence of this light.

text: As all matter, the human body radiates some of a person's energy away as infrared light.

text: As all matter, the human body radiates some of a person's energy away as

text: infrared

text: light.

text: Lübeck, a Hanseatic city and cultural centre on the shores of the Baltic Sea, was easy to find under the light of the full moon on the Saturday night of 28 March 1942 and the early hours of 29 March (Palm Sunday). Because of the hoar frost there was clear visibility and the waters of the Trave, the Elbe-Lübeck Canal, Wakenitz and the Bay of Lübeck were reflecting the moonlight. 234 Wellington and Stirling bombers dropped about 400 tons of bombs including 25,000 incendiary devices and a number of 1.8 tonne landmines. RAF Bomber Command lost twelve aircraft in the attack.

text: Lübeck

text: , a

text: Hanseatic

text: city and cultural centre on the shores of the

text: Baltic Sea

text: , was easy to find under the light of the full moon on the Saturday night of 28 March 1942 and the early hours of 29 March (

text: Palm Sunday

text: ). Because of the

text: hoar frost

text: there was clear visibility and the waters of the

text: Trave

text: , the

text: Elbe-Lübeck Canal

text: Wakenitz

text: and the

text: Bay of Lübeck

text: were reflecting the moonlight. 234

text: Wellington

text: and

text: Stirling

text: bombers dropped about 400 tons of bombs including 25,000

text: incendiary device

text: s and a number of 1.8 tonne landmines.

text: RAF Bomber Command

text: lost twelve aircraft in the attack.

text: More energy is contained in higher frequency light based upon the formula of E = h\nu, where h is the Planck constant and \nu is frequency.  Metal collectors down convert higher frequency light by producing a series of Compton shifts into an abundance of lower frequency light.  Glass or ceramic coatings with high transmission in the visible and UV and effective absorption in the IR (heat blocking) trap metal absorbed low frequency light from radiation loss.  Convection insulation prevents mechanical losses transferred through gas.  Once collected as heat, thermos containment efficiency improves significantly with increased size.  Unlike Photovoltaic technologies that often degrade under concentrated light, Solar Thermal depends upon light concentration that requires a clear sky to reach suitable temperatures.

text: More energy is contained in higher frequency light based upon the formula of E = h\nu, where h is the

text: Planck constant

text: and \nu is frequency.  Metal collectors down convert higher frequency light by producing a series of Compton shifts into an abundance of lower frequency light.  Glass or ceramic coatings with high transmission in the visible and UV and effective absorption in the IR (heat blocking) trap metal absorbed low frequency light from radiation loss.  Convection insulation prevents mechanical losses transferred through gas.  Once collected as heat, thermos containment efficiency improves significantly with increased size.  Unlike Photovoltaic technologies that often degrade under concentrated light, Solar Thermal depends upon light concentration that requires a clear sky to reach suitable temperatures.

text: is intensity of light beam before transmission

text: A colloidal crystal is a highly ordered array of particles that forms over a long range (from a few millimeters to one centimeter in length); colloidal crystals have appearance and properties roughly analogous to their atomic or molecular counterparts. It has been known for many years that, due to repulsive Coulombic interactions, electrically charged macromolecules in an aqueous environment can exhibit long-range crystal-like correlations, with interparticle separation distances often being considerably greater than the individual particle diameter. Periodic arrays of spherical particles give rise to interstitial voids (the spaces between the particles), which act as a natural diffraction grating for visible light waves, when the interstitial spacing is of the same order of magnitude as the incident lightwave. In these cases in nature, brilliant iridescence (or play of colours) is attributed to the diffraction and constructive interference of visible lightwaves according to Bragg’s law, in a matter analogous to the scattering of X-rays in crystalline solid. The effects occur at visible wavelengths because the separation parameter d is much larger than for true crystals.

text: A

text: colloidal crystal

text: is a highly

text: ordered

text: array of particles that forms over a long range (from a few

text: millimeters

text: to one

text: centimeter

text: in length); colloidal crystals have appearance and properties roughly

text: analogous

text: to their atomic or molecular counterparts. It has been known for many years that, due to

text: repulsive

text: Coulombic

text: interactions,

text: electrically charged

text: macromolecules

text: in an

text: aqueous

text: environment can exhibit long-range

text: crystal

text: -like correlations, with interparticle separation distances often being considerably greater than the individual particle diameter. Periodic arrays of spherical particles give rise to

text: interstitial voids

text: (the spaces between the particles), which act as a natural

text: diffraction grating

text: for

text: visible light waves

text: , when the interstitial spacing is of the same

text: order of magnitude

text: as the

text: incident

text: lightwave. In these cases in nature, brilliant

text: iridescence

text: (or play of colours) is attributed to the diffraction and

text: constructive interference

text: of visible lightwaves according to Bragg’s law, in a matter analogous to the

text: scattering

text: of

text: X-rays

text: in crystalline solid. The effects occur at visible wavelengths because the separation parameter d is much larger than for true crystals.

text: Generally, EM radiation, or EMR (the designation "radiation" excludes static electric and magnetic and near fields), is classified by wavelength into radio, microwave, infrared, the visible region that we perceive as light, ultraviolet, X-rays and gamma rays.

text: Generally, EM radiation, or EMR (the designation "radiation" excludes static electric and magnetic and

text: near fields

text: ), is classified by wavelength into

text: radio

text: microwave

text: infrared

text: , the visible region that we perceive as light,

text: ultraviolet

text: X-ray

text: s and

text: gamma rays

text: The AOD (automatic overdrive) is a four-speed automatic transmission with overdrive.  Introduced in 1980, it was Ford's first four-speed automatic overdrive transmission.  The gearset design is based on the Ford "X" automatic transmissions used during the 1950s, 60s, and 70s.  The AOD replaced many of Ford's older transmissions such as the C4, C5, and light duty applications of the FMX.

text: The AOD (automatic overdrive) is a four-speed

text: automatic transmission

text: with

text: overdrive

text: .  Introduced in 1980, it was

text: Ford

text: 's first four-speed automatic overdrive transmission.  The gearset design is based on the Ford "X" automatic transmissions used during the 1950s, 60s, and 70s.  The AOD replaced many of Ford's older transmissions such as the C4, C5, and light duty applications of the FMX.

text: In the effort to reduce light pollution, researchers have developed a "Unified System of Photometry," which is a way to measure how much or what kind of street lighting is needed. The Unified System of Photometry allows light fixtures to be designed to reduce energy use while maintaining or improving perceptions of visibility, safety, and security. There was a need to create a new system of light measurement at night because the biological way in which the eye’s rods and cones process light is different in nighttime conditions versus daytime conditions. Using this new system of photometry, results from recent studies have indicated that replacing traditional, yellowish, high-pressure sodium (HPS) lights with "cool" white light sources, such as induction, fluorescent, ceramic metal halide, or LEDs can actually reduce the amount of electric power used for lighting while maintaining or improving visibility in nighttime conditions.

text: In the effort to reduce light pollution, researchers have developed a "Unified System of Photometry," which is a way to measure how much or what kind of

text: street light

text: ing is needed. The Unified System of Photometry allows light fixtures to be designed to reduce energy use while maintaining or improving perceptions of visibility, safety, and security. There was a need to create a new system of light measurement at night because the biological way in which the eye’s rods and cones process light is different in nighttime conditions versus daytime conditions. Using this new system of photometry, results from recent studies have indicated that replacing traditional, yellowish,

text: high-pressure sodium

text: (HPS) lights with "cool" white light sources, such as induction,

text: fluorescent

text: ceramic metal halide

text: , or

text: LED

text: s can actually reduce the amount of electric power used for lighting while maintaining or improving visibility in nighttime conditions.

text: Electromagnetic radiation and matter have a symbiotic relationship. Radiation does not simply act on a material, nor is it simply acted upon by a given material. Radiation interacts with matter. Cloaking applications which employ metamaterials alter how objects interact with the electromagnetic spectrum. The guiding vision for the metamaterial cloak is a device that directs the flow of light smoothly around an object, like water flowing past a rock in a stream, without reflection, rendering the object invisible. In reality, the simple cloaking devices of the present are imperfect, and have  limitations.One challenge up to the present date has been the inability of metamaterials, and cloaking devices, to interact at frequencies, or wavelengths, within the visible light spectrum.

text: Electromagnetic radiation

text: and matter have a symbiotic relationship. Radiation does not simply act on a material, nor is it simply acted upon by a given material. Radiation interacts with

text: matter

text: . Cloaking applications which employ

text: metamaterial

text: s alter how objects interact with the

text: electromagnetic spectrum

text: . The guiding vision for the metamaterial cloak is a device that directs the flow of light smoothly around an object, like water flowing past a rock in a stream, without

text: reflection

text: , rendering the object invisible. In reality, the simple cloaking devices of the present are imperfect, and have  limitations.One challenge up to the present date has been the inability of metamaterials, and cloaking devices, to interact at

text: frequencies

text: , or

text: wavelength

text: s, within the visible light spectrum.

text: In the real world, objects and surfaces are visible due to the fact that they are reflecting light. This reflected light then illuminates other objects in turn. From that simple observation, two principles follow.

text: Water is relatively transparent to visible light, near ultraviolet light, and far-red light, but it absorbs most ultraviolet light, infrared light, and microwaves. Most photoreceptors and photosynthetic pigments utilize the portion of the light spectrum that is transmitted well through water. Microwave ovens take advantage of water's opacity to microwave radiation to heat the water inside of foods. The very weak onset of absorption in the red end of the visible spectrum lends water its intrinsic blue hue (see Color of water).

text: Water is relatively transparent to

text: visible light

text: near ultraviolet

text: light, and

text: far-red

text: light, but it absorbs most

text: ultraviolet light

text: infrared light

text: , and

text: microwave

text: s. Most

text: photoreceptors

text: and

text: photosynthetic pigment

text: s utilize the portion of the light spectrum that is transmitted well through water.

text: Microwave ovens

text: take advantage of water's opacity to microwave radiation to heat the water inside of foods. The very weak onset of absorption in the red end of the visible spectrum lends water its intrinsic blue hue (see

text: Color of water

text: Visible-light astronomy encompasses a wide variety of observations via telescopes that are sensitive in the range of visible light (optical telescopes).  It includes imaging, where a picture of some sort is made of the object; photometry, where the amount of light coming from an object is measured, spectroscopy, where the distribution of that light with respect to its wavelength is measured, and polarimetry where the polarisation state of that light is measured.  An example of spectroscopy is the study of spectral lines to understand of what kind of matter light is going through. Visible astronomy also includes looking up at night (skygazing).  Visible-light astronomy is part of optical astronomy, and differs from astronomies based on invisible types of light in the electromagnetic radiation spectrum, such as radio waves, infrared waves, ultraviolet waves, X-ray waves and gamma-ray waves.

text: Visible-light astronomy encompasses a wide variety of

text: observation

text: s via

text: telescope

text: s that are sensitive in the range of

text: visible light

text: optical telescope

text: s).  It includes imaging, where a picture of some sort is made of the object;

text: photometry

text: , where the amount of light coming from an object is measured,

text: spectroscopy

text: , where the distribution of that light with respect to its

text: wavelength

text: is measured, and

text: polarimetry

text: where the

text: polarisation

text: state of that light is measured.  An example of

text: spectroscopy

text: is the study of

text: spectral line

text: s to understand of what kind of

text: matter

text: light is going through. Visible astronomy also includes looking up at night (

text: skygazing

text: ).  Visible-light astronomy is part of optical astronomy, and differs from astronomies based on invisible types of light in the

text: electromagnetic radiation spectrum

text: , such as

text: radio waves

text: infrared waves

text: ultraviolet waves

text: X-ray waves

text: and

text: gamma-ray waves

text: Many metal complexes are colored due to d-d electronic transitions. Visible light of the correct wavelength is absorbed, promoting a lower d-electron to a higher excited state. This absorption of light causes color. These colors are usually quite faint, however. This is because of two selection rules:

text: Many metal complexes are colored due to d-d electronic transitions. Visible light of the correct wavelength is absorbed, promoting a lower d-electron to a higher excited state. This absorption of light causes color. These colors are usually quite faint, however. This is because of two

text: selection rule

text: s:

text: Absorption spectroscopy – Anders Jonas Ångström – Astronomical spectroscopy – Astronomy – Black body – Blazar – Bremsstrahlung – Caesium – Cherenkov radiation – Color – Diffraction – Digital signal processing – Direct-sequence spread spectrum – Dispersion (optics) – Eigenstate – Eigenvalue – Electromagnetic radiation – Electromagnetic spectroscopy – Electromagnetic spectrum – Electromagnetism – Emission line – Emission spectrum – FM broadcasting – Frequency domain – Frequency hopping – Frequency spectrum – Gamma-ray burst – Hamiltonian (quantum mechanics) – History of radio – Hue – Isotope – Light – Optical brightener – Particle in a spherically symmetric potential – Piezoelectricity – Power spectrum – RADAR – Radio frequency – Radio – Radiocommunications Agency – Redshift – SETI – Spectrogram – Spectrometer – Spectroscopy – Spectrum analyzer – Sunyaev–Zel'dovich effect – Supernova – Telecommunication – Timbre – Very high frequency – Visible light – Visible spectrum – White noise

text: Absorption spectroscopy

text: Anders Jonas Ångström

text: Astronomical spectroscopy

text: Astronomy

text: Black body

text: Blazar

text: Bremsstrahlung

text: Caesium

text: Cherenkov radiation

text: Color

text: Diffraction

text: Digital signal processing

text: Direct-sequence spread spectrum

text: Dispersion (optics)

text: Eigenstate

text: Eigenvalue

text: Electromagnetic radiation

text: Electromagnetic spectroscopy

text: Electromagnetic spectrum

text: Electromagnetism

text: Emission line

text: Emission spectrum

text: FM broadcasting

text: Frequency domain

text: Frequency hopping

text: Frequency spectrum

text: Gamma-ray burst

text: Hamiltonian (quantum mechanics)

text: History of radio

text: Hue

text: Isotope

text: Light

text: Optical brightener

entity_name: Particle in a spherically symmetric potential

text: Particle in a spherically symmetric potential

text: Piezoelectricity

text: Power spectrum

text: RADAR

text: Radio frequency

text: Radio

text: Radiocommunications Agency

text: Redshift

entity_name: Search for extraterrestrial intelligence

text: SETI

text: Spectrogram

text: Spectrometer

text: Spectroscopy

text: Spectrum analyzer

text: Sunyaev–Zel'dovich effect

text: Supernova

text: Telecommunication

text: Timbre

text: Very high frequency

text: Visible light

text: Visible spectrum

text: White noise

text: The propagation of light through the core of an optical fiber is based on total internal reflection of the lightwave. Rough and irregular surfaces, even at the molecular level of the glass, can cause light rays to be reflected in many random directions. This type of reflection is referred to as "diffuse reflection", and it is typically characterized by wide variety of reflection angles. Most objects that can be seen with the naked eye are visible due to diffuse reflection. Another term commonly used for this type of reflection is "light scattering". Light scattering from the surfaces of objects is our primary mechanism of physical observation.Light scattering from many common surfaces can be modelled by lambertian reflectance.

text: The propagation of light through the core of an optical fiber is based on total internal reflection of the lightwave. Rough and irregular surfaces, even at the molecular level of the glass, can cause light rays to be reflected in many random directions. This type of reflection is referred to as "

text: diffuse reflection

text: ", and it is typically characterized by wide variety of reflection angles. Most objects that can be seen with the naked eye are visible due to diffuse reflection. Another term commonly used for this type of reflection is "

text: light scattering

text: ". Light scattering from the surfaces of objects is our primary mechanism of physical observation.Light scattering from many common surfaces can be modelled by

text: lambertian reflectance

text: Light that travels through transparent matter does so at a lower speed than c, the speed of light in a vacuum. For example, photons engage in so many collisions on the way from the core of the sun that radiant energy can take about a million years to reach the surface; however, once in open space, a photon takes only 8.3 minutes to reach Earth. The factor by which the speed is decreased is called the refractive index of the material. In a classical wave picture, the slowing can be explained by the light inducing electric polarization in the matter, the polarized matter radiating new light, and that new light interfering with the original light wave to form a delayed wave. In a particle picture, the slowing can instead be described as a blending of the photon with quantum excitations of the matter to produce quasi-particles known as polariton (other quasi-particles are phonons and excitons); this polariton has a nonzero effective mass, which means that it cannot travel at c. Light of different frequencies may travel through matter at different speeds; this is called dispersion (not to be confused with scattering). In some cases, it can result in extremely slow speeds of light in matter. The effects of photon interactions with other quasi-particles may be observed directly in Raman scattering and Brillouin scattering.

text: Light that travels through transparent matter does so at a lower speed than c, the speed of light in a vacuum. For example, photons engage in so many collisions on the way from the

text: core

text: of the sun that radiant energy can take about a million years to reach the surface; however, once in open space, a photon takes only 8.3 minutes to reach Earth. The factor by which the speed is decreased is called the

text: refractive index

text: of the material. In a classical wave picture, the slowing can be explained by the light inducing

text: electric polarization

text: in the matter, the polarized matter radiating new light, and that new light interfering with the original light wave to form a delayed wave. In a particle picture, the slowing can instead be described as a blending of the photon with quantum excitations of the matter to produce

text: quasi-particle

text: s known as

text: polariton

text: (other quasi-particles are

text: phonon

text: s and

text: exciton

text: s); this polariton has a nonzero

text: effective mass

text: , which means that it cannot travel at c. Light of different frequencies may travel through matter at

text: different speeds

text: ; this is called

text: dispersion

text: (not to be confused with scattering). In some cases, it can result in

text: extremely slow speeds of light

text: in matter. The effects of photon interactions with other quasi-particles may be observed directly in

text: Raman scattering

text: and

text: Brillouin scattering

text: The carapace of O. ocellatus is slightly wider than long, at  wide, and  long. This distinguishes it from other crabs in the family Portunidae, which often have elongated lateral spines. The carapace is yellow-grey or light purplish, with "leopardlike clusters of purple dots", and 3–5 spines along the edge behind each eye. O. ovalipes is almost identical to O. floridanus, which lives in the Gulf of Mexico, but can be separated from the sympatric O. stephensoni by the purple spots, which O. stephensoni lacks.

text: The

text: carapace

text: of O. ocellatus is slightly wider than long, at  wide, and  long. This distinguishes it from other crabs in the family

text: Portunidae

text: , which often have elongated lateral spines. The carapace is yellow-grey or light purplish, with "leopardlike clusters of purple dots", and 3–5 spines along the edge behind each eye. O. ovalipes is almost identical to

text: O. floridanus

text: , which lives in the

text: Gulf of Mexico

text: , but can be separated from the

text: sympatric

text: O. stephensoni

text: by the purple spots, which O. stephensoni lacks.

text: Mercury is technically brightest as seen from Earth when it is at a full phase. Although Mercury is farthest from Earth when it is full, the greater illuminated area that is visible and the opposition brightness surge more than compensates for the distance. The opposite is true for Venus, which appears brightest when it is a crescent, because it is much closer to Earth than when gibbous.

text: Mercury is technically brightest as seen from Earth when it is at a full phase. Although Mercury is farthest from Earth when it is full, the greater illuminated area that is visible and the

text: opposition brightness surge

text: more than compensates for the distance. The opposite is true for Venus, which appears brightest when it is a

text: crescent

text: , because it is much closer to Earth than when

text: gibbous

text: Newell is located at  (44.716261, -103.423094).

text: Michael was selected to create the commemorative artwork for the Museum of Flight 50th Anniversary in Seattle. The large artwork depicting many of the planes in the museum was auctioned off at the anniversary gala in August 2015.

text: Michael was selected to create the commemorative artwork for the

text: Museum of Flight

text: 50th Anniversary in Seattle. The large artwork depicting many of the planes in the museum was auctioned off at the anniversary gala in August 2015.

text: The charts at "Understanding wavelengths In fiber optics" and "Optical power loss (attenuation) in fiber" illustrate the relationship of visible light to the IR frequencies used, and show the absorption water bands between 850, 1300 and 1550 nm.

text: In 2002, she directed in the United States for the first time. The resulting movie Iron Jawed Angels about the women's suffrage movement was produced by HBO Films and released in 2004.

text: In 2002, she directed in the

text: United States

text: for the first time. The resulting movie

text: Iron Jawed Angels

text: about the

text: women's suffrage

text: movement was produced by

text: HBO Films

text: and released in 2004.

text: Technical dives in waters where the diver's vision is severely impeded by low-visibility conditions, caused by turbidity or silt out and low light conditions due to depth or enclosure, require greater competence. The combination of low visibility and strong current can make dives in these conditions extremely hazardous, particularly in an overhead environment, and greater skill and reliable and familiar equipment are needed to manage this risk. Limited visibility diving can cause disorientation, potentially leading to loss of sense of direction, loss of effective buoyancy control, etc. Divers in extremely limited visibility situations depend on their instruments such as dive lights, pressure gauges, compass, depth gauge, bottom timer, dive computer, etc., and guidelines for orientation and information. Training for cave and wreck diving includes techniques for managing extreme low visibility, as finding the way out of an overhead environment before running out of gas is a safety-critical skill.

text: Technical dives in waters where the diver's vision is severely impeded by low-visibility conditions, caused by turbidity or

text: silt out

text: and low light conditions due to depth or enclosure, require greater competence. The combination of low visibility and strong current can make dives in these conditions extremely hazardous, particularly in an overhead environment, and greater skill and reliable and familiar equipment are needed to manage this risk. Limited visibility diving can cause disorientation, potentially leading to loss of sense of direction, loss of effective buoyancy control, etc. Divers in extremely limited visibility situations depend on their instruments such as

text: dive light

text: s, pressure gauges, compass,

text: depth gauge

text: , bottom timer, dive computer, etc., and guidelines for orientation and information. Training for cave and wreck diving includes techniques for managing extreme low visibility, as finding the way out of an overhead environment before running out of gas is a safety-critical skill.

text: The term specular means that light is perfectly reflected in a mirror-like way from the light source to the viewer. Specular reflection is visible only where the surface normal is oriented precisely halfway between the direction of incoming light and the direction of the viewer; this is called the half-angle direction because it bisects (divides into halves) the angle between the incoming light and the viewer. Thus, a specularly reflecting surface would show a specular highlight as the perfectly sharp reflected image of a light source. However, many shiny objects show blurred specular highlights.

text: The term specular means that light is

text: perfectly reflected

text: in a mirror-like way from the light source to the viewer. Specular reflection is visible only where the

text: surface normal

text: is oriented precisely halfway between the direction of incoming light and the direction of the viewer; this is called the half-angle direction because it bisects (divides into halves) the angle between the incoming light and the viewer. Thus, a specularly reflecting surface would show a specular highlight as the perfectly sharp reflected image of a light source. However, many shiny objects show blurred specular highlights.