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Arthur König
Arthur Peter König (September 13, 1856, Krefeld – October 26, 1901, Berlin) devoted his short life to physiological optics. Born with congenital kyphosis he studied in Bonn and Heidelberg, moving to Berlin in the fall of 1879 where he studied under Hermann von Helmholtz, whose assistant he became in 1882. After obtaining a doctoral degree in 1882 he qualified for a professorial position in 1884. In 1890 he became director of the physical department of the Physiological Institute of the University of Berlin. In the same year he married Laura Köttgen with whom he had a son, Arthur, who became an astronomer. Circulatory problems caused by his kyphosis resulted in his premature death in 1901.Source of biographical information: M. Richter, Arthur König zum Gedächtnis, Die Farbe 5 (1956) No.1/2, 1–6. Originally working in physics, he began in 1883 to concentrate on physiological optics where he published over thirty papers, some of seminal importance. Among these are the 1886 pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Krefeld
Krefeld ( , ; li, Krieëvel ), also spelled Crefeld until 1925 (though the spelling was still being used in British papers throughout the Second World War), is a city in North Rhine-Westphalia, Germany. It is located northwest of Düsseldorf, its center lying just a few kilometers to the west of the river Rhine; the borough of Uerdingen is situated directly on the Rhine. Because of its economic past, Krefeld is often referred to as the "Velvet and Silk City". It is accessed by the autobahns A57 (Cologne– Nijmegen) and A44 (Aachen–Düsseldorf– Dortmund–Kassel). Krefeld's residents now speak ', or standard German, but the native dialect is a Low Franconian variety, sometimes locally called ', ', ', or sometimes simply '. The Uerdingen line isogloss, separating general dialectical areas in Germany and neighboring Germanic-speaking countries, runs through and is named after Krefeld's Uerdingen district, originally an independent municipality. History Early history Records ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dichromats
Dichromacy (from Greek ''di'', meaning "two" and ''chromo'', meaning "color") is the state of having two types of functioning photoreceptors, called cone cells, in the eyes. Organisms with dichromacy are called dichromats. Dichromats require only two primary colors to be able to represent their visible gamut. By comparison, trichromats need three primary colors, and tetrachromats need four. Likewise, every color in a dichromat's gamut can be evoked with monochromatic light. By comparison, every color in a trichromat's gamut can be evoked with a combination of monochromatic light and white light. Dichromacy in humans is a color vision deficiency in which one of the three cone cells is absent or not functioning and color is thereby reduced to two dimensions."Guidelines: Colour Blindness." Tiresias.org. Retrie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
19th-century German Physicists
The 19th (nineteenth) century began on 1 January 1801 ( MDCCCI), and ended on 31 December 1900 ( MCM). The 19th century was the ninth century of the 2nd millennium. The 19th century was characterized by vast social upheaval. Slavery was abolished in much of Europe and the Americas. The First Industrial Revolution, though it began in the late 18th century, expanding beyond its British homeland for the first time during this century, particularly remaking the economies and societies of the Low Countries, the Rhineland, Northern Italy, and the Northeastern United States. A few decades later, the Second Industrial Revolution led to ever more massive urbanization and much higher levels of productivity, profit, and prosperity, a pattern that continued into the 20th century. The Islamic gunpowder empires fell into decline and European imperialism brought much of South Asia, Southeast Asia, and almost all of Africa under colonial rule. It was also marked by the collapse of the large S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1901 Deaths
Nineteen or 19 may refer to: * 19 (number), the natural number following 18 and preceding 20 * one of the years 19 BC, AD 19, 1919, 2019 Films * ''19'' (film), a 2001 Japanese film * ''Nineteen'' (film), a 1987 science fiction film Music * 19 (band), a Japanese pop music duo Albums * ''19'' (Adele album), 2008 * ''19'', a 2003 album by Alsou * ''19'', a 2006 album by Evan Yo * ''19'', a 2018 album by MHD * ''19'', one half of the double album ''63/19'' by Kool A.D. * ''Number Nineteen'', a 1971 album by American jazz pianist Mal Waldron * ''XIX'' (EP), a 2019 EP by 1the9 Songs * "19" (song), a 1985 song by British musician Paul Hardcastle. * "Nineteen", a song by Bad4Good from the 1992 album ''Refugee'' * "Nineteen", a song by Karma to Burn from the 2001 album ''Almost Heathen''. * "Nineteen" (song), a 2007 song by American singer Billy Ray Cyrus. * "Nineteen", a song by Tegan and Sara from the 2007 album '' The Con''. * "XIX" (song), a 2014 song by Slipkno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1856 Births
Events January–March * January 8 – Borax deposits are discovered in large quantities by John Veatch in California. * January 23 – American paddle steamer SS ''Pacific'' leaves Liverpool (England) for a transatlantic voyage on which she will be lost with all 186 on board. * January 24 – U.S. President Franklin Pierce declares the new Free-State Topeka government in "Bleeding Kansas" to be in rebellion. * January 26 – First Battle of Seattle: Marines from the suppress an indigenous uprising, in response to Governor Stevens' declaration of a "war of extermination" on Native communities. * January 29 ** The 223-mile North Carolina Railroad is completed from Goldsboro through Raleigh and Salisbury to Charlotte. ** Queen Victoria institutes the Victoria Cross as a British military decoration. * February ** The Tintic War breaks out in Utah. ** The National Dress Reform Association is founded in the United States to promote "rational" dress for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ebbinghaus
Ebbinghaus is a German surname. It may refer to: * Bernhard Ebbinghaus (Born 1961), a German sociologist * Heinz-Dieter Ebbinghaus (born 1939), a German mathematician * Hermann Ebbinghaus (1850–1909), a German psychologist ** the Ebbinghaus illusion, in experimental psychology * Julius Ebbinghaus Julius Ebbinghaus (9 November 1885, Berlin – 16 June 1981, Marburg an der Lahn) was a German philosopher, one of the closest followers of Immanuel Kant active in the twentieth century. He was influenced by the Heidelberg school of neo-Kantiani ... (1885–1981), a German philosopher {{surname ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhodopsin
Rhodopsin, also known as visual purple, is a protein encoded by the RHO gene and a G-protein-coupled receptor (GPCR). It is the opsin of the rod cells in the retina and a light-sensitive receptor protein that triggers visual phototransduction in rods. Rhodopsin mediates dim light vision and thus is extremely sensitive to light. When rhodopsin is exposed to light, it immediately photobleaches. In humans, it is regenerated fully in about 30 minutes, after which the rods are more sensitive. Defects in the rhodopsin gene cause eye diseases such as retinitis pigmentosa and congenital stationary night blindness. Names Rhodopsin was discovered by Franz Christian Boll in 1876. The name rhodospsin derives from Ancient Greek () for "rose", due to its pinkish color, and () for "sight". It was coined in 1878 by the German physiologist Wilhelm Friedrich Kühne (1837-1900). When George Wald discovered that rhodopsin is a holoprotein, consisting of retinal and an apoprotein, he c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fechner
Fechner is a surname. Notable people with the surname include: * Carl-A. Fechner (born 1952), German documentary filmmaker * Christian Fechner (1944–2008), French film producer and screenwriter * Gino Fechner (born 1997), German footballer * Gustav Fechner (1801–1887), German experimental psychologist, physicist and philosopher * Harry Fechner (born 1950), German football defender * Johannes Fechner (born 1965), German politician * Max Fechner (1892–1973), Minister of Justice of the GDR * Robert Fechner (1876–1939), American union leader * Sebastian Fechner (born 1983), Polish footballer See also * Fechner color, an illusion of color * Weber–Fechner law * Fechner (crater) Fechner is a lunar impact crater that lies on the far side of the Moon's southern hemisphere, attached to the western rim of the large walled plain Planck. The eastern rim of Fechner intersects the Vallis Planck, a long, wide cleft in the surface ..., a lunar crater * 11041 Fechner (1989 SH2), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Color Blindness
Color blindness or color vision deficiency (CVD) is the decreased ability to color vision, see color or differences in color. It can impair tasks such as selecting ripe fruit, choosing clothing, and reading traffic lights. Color blindness may make some academic activities more difficult. However, issues are generally minor, and the colorblind automatically develop adaptations and coping mechanisms. People with achromatopsia, total color blindness (achromatopsia) may also be Hemeralopia, uncomfortable in bright environments and have visual impairment, decreased visual acuity. The most common cause of color blindness is an Heredity, inherited problem or variation in the functionality of one or more of the three classes of cone cells in the retina, which mediate color vision. The most common form is caused by a genetic disorder called congenital red–green color blindness. Males are more likely to be color blind than females, because the genes responsible for the most common for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monochromats
Monochromacy (from Greek ''mono'', meaning "one" and ''chromo'', meaning "color") is the ability of organisms or machines to perceive only light intensity, without respect to spectral composition (color). Organisms with monochromacy are called monochromats. Many mammals, such as cetaceans, the owl monkey and the Australian sea lion (pictured at right) are monochromats. In humans, absence of color vision is one among several other symptoms of severe inherited or acquired diseases, including achromatopsia or blue cone monochromacy, together affecting about 1 in 30,000 people. The affected can distinguish light, dark, and shades of gray but not color. Humans Human vision relies on a duplex retina, comprising two types of photoreceptor cells. Rods are primarily responsible for dim-light scotopic vision and cones are primarily responsible for day-light photopic vision. For all known vertebrates, scotopic vision is monochromatic, since there is typically only one class of rod cell. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trichromats
Trichromacy or trichromatism is the possessing of three independent channels for conveying color information, derived from the three different types of cone cells in the eye. Organisms with trichromacy are called trichromats. The normal explanation of trichromacy is that the organism's retina contains three types of color receptors (called cone cells in vertebrates) with different absorption spectra. In actuality the number of such receptor types may be greater than three, since different types may be active at different light intensities. In vertebrates with three types of cone cells, at low light intensities the rod cells may contribute to color vision. Humans and other animals that are trichromats Humans and some other mammals have evolved trichromacy based partly on pigments inherited from early vertebrates. In fish and birds, for example, four pigments are used for vision. These extra cone receptor visual pigments detect energy of other wavelengths, sometimes including u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
