text
stringlengths 11
1.65k
| source
stringlengths 38
44
|
|---|---|
Aquiherbosa An aquiherbosa is a plant community of herbaceous plants that exists in abundantly wet areas. This can refer to plant communities in wetlands, ponds, or other bodies of water.
|
https://en.wikipedia.org/wiki?curid=37575487
|
Nuummite is a rare metamorphic rock that consists of the amphibole minerals gedrite and anthophyllite. It is named after the area of Nuuk in Greenland, where it was found. is usually black in colour and opaque. It consists of two amphiboles, gedrite and anthophyllite, which form exsolution lamellae that give the rock its typical iridescence. Other common minerals in the rock are pyrite, pyrrhotite and chalcopyrite, which form shimmering yellow bands in polished specimens. In Greenland the rock was formed by two consecutive metamorphic overprints of an originally igneous rock. The intrusion took place in the Archean around 2800 million years ago and the metamorphic overprint was dated at 2700 and 2500 million years ago. The rock was first discovered in 1810 in Greenland by the mineralogist K. L. Giesecke. Due to its iridescent nature, this rare stone is sought after by gemstone dealers, collectors and those interested in the esoteric. It is often sold with tumble finishing. In 2009, a new Variety of Nuumite was discovered in central Mauritania. Under its unofficial name Jenakite, this Variety is distinctive due to the presence and high density of blue and green Anthophyllite needle-like crystals. Nuumite from Greenland has no blue or green Anthophyllite needle-like crystals.
|
https://en.wikipedia.org/wiki?curid=37579789
|
Fuel factor The fuel factor, f, is the ratio of created CO to depleted oxygen in a combustion reaction, used to check the accuracy of an emission measurement system. It can be calculated using the equation Where %O is the percent O by volume, dry basis, %CO is the percent CO by volume, dry basis, and 20.9 is the percent O by volume in ambient air. The can be corrected for the amount of CO, by adding the percent CO on a dry basis to the CO, and subtracting half of the percent CO from the O.
|
https://en.wikipedia.org/wiki?curid=37591765
|
Cardiovirus B is a species in the genus "Cardiovirus" and is represented by two isolates, Saffold virus (SAFV) and Theiler's murine encephalomyelitis virus (TMEV).
|
https://en.wikipedia.org/wiki?curid=37596367
|
Colloidal probe technique The colloidal probe technique is commonly used to measure interaction forces acting between colloidal particles and/or planar surfaces in air or in solution. This technique relies on the use of an atomic force microscope (AFM). However, instead of a cantilever with a sharp AFM tip, one uses the "colloidal probe". The colloidal probe consists of a colloidal particle of few micrometers in diameter that is attached to an AFM cantilever. The colloidal probe technique can be used in the "sphere-plane" or "sphere-sphere" geometries ("see figure"). One typically achieves a force resolution between 1 and 100 pN and a distance resolution between 0.5 and 2 nm. The colloidal probe technique has been developed in 1991 independently by Ducker and Butt. Since its development this tool has gained wide popularity in numerous research laboratories, and numerous reviews are available in the scientific literature. Alternative techniques to measure force between surfaces involve the surface forces apparatus, total internal reflection microscopy, and optical tweezers techniques to with video microscopy. The possibility to measure forces involving particles and surfaces directly is essential since such forces are relevant in a variety of processes involving colloidal and polymeric systems. Examples include particle aggregation, suspension rheology, particle deposition, and adhesion processes. One can equally study similar biological phenomena, such as deposition of bacteria or the infection of cells by viruses
|
https://en.wikipedia.org/wiki?curid=37605500
|
Colloidal probe technique Forces are equally most informative to investigate the mechanical properties of interfaces, bubbles, capsules, membranes, or cell walls. Such measurements permit to make conclusions about the elastic or plastic deformation or eventual rupture in such systems. The colloidal probe technique provides a versatile tool to measure such forces between a colloidal particle and a planar substrate or between two colloidal particles (see figure above). The particles used in such experiments have typically a diameter between 1–10 μm. Typical applications involve measurements of electrical double layer forces and the corresponding surface potentials or surface charge, van der Waals forces, or forces induced by adsorbed polymers. The colloidal probe technique uses a standard AFM for the force measurements. But instead the AFM cantilever with an attached sharp tip one uses the "colloidal probe". This colloidal probe is normally obtained by attaching a colloidal particle to a cantilever. By recording the deflection of the cantilever as a function of the vertical displacement of the AFM scanner one can extract the force acting between the probe and the surface as a function of the surface separation. This type of AFM operation is referred to as the "force mode". With this probe, one can study interactions between various surfaces and probe particles in the "sphere-plane geometry"
|
https://en.wikipedia.org/wiki?curid=37605500
|
Colloidal probe technique It is also possible to study forces between colloidal particles by attaching another particle to the substrate and perform the measurement in the "sphere-sphere geometry", see figure above. The force mode used in the colloidal probe technique is illustrated in the figure on the left. The scanner is fabricated from piezoelectric crystals, which enable its positioning with a precision better than 0.1 nm. The scanner is lifted towards the probe and thereby one records the scanner displacement "D". At the same time, the deflection of the cantilever "ξ" is monitored as well, typically with a comparable precision. One measures the deflection by focusing a light beam originating from a non-coherent laser diode to the back of the cantilever and detecting the reflected beam with a split photodiode. The lever signal "S" represents the difference in the photocurrents originating from the two halves of the diode. The lever signal is therefore proportional to the deflection "ξ". During an approach-retraction cycle, one records the lever signal "S" as a function of the vertical displacement "D" of the scanner. Suppose for the moment that the probe and the substrate are hard and non-deformable objects and that no forces are acting between them when they are not in contact. In such a situation, one refers to a "hard-core repulsion". The cantilever will thus not deform as long not being in contact with the substrate. When the cantilever touches the substrate, its deflection will be the same as the displacement of the substrate
|
https://en.wikipedia.org/wiki?curid=37605500
|
Colloidal probe technique This response is referred to as the "constant compliance" or contact region. The lever signal "S" as a function of the scanner displacement "D" is shown in the figure below. This graph consists of two straight lines resembling a hockey-stick. When the surfaces are not in contact, the lever signal will be denoted as "S". This value corresponds to the non-deformed lever. In the constant compliance region, the lever signal is simply a linear function of the displacement, and can be represented as a straight line The parameters "a" and "b" can be obtained from a least-squares fit of the constant compliance region. The inverse slope "a" is also referred to as the optical lever sensitivity. By inverting this relation for the lever signal "S", which corresponds to the non-deformed lever, one can accurately obtain the contact point from "D" = ("S" − "b")/"a". Depending on the substrate, the precision in determining this contact point is between 0.5–2 nm. In the constant compliance region, the lever deformation is given by In this fashion, one can detect deflections of the cantilever with typical resolution of better than 0.1 nm. Let us now consider the relevant situation where the probe and the substrate interact. Let us denote by "F"("h") the force between the probe and the substrate. This force depends on the surface separation "h". In equilibrium, this force is compensated by the restoring force of the spring, which is given by the Hooke's law where "k" is the spring constant of the cantilever
|
https://en.wikipedia.org/wiki?curid=37605500
|
Colloidal probe technique Typical spring constants of AFM cantilevers are in the range of 0.1−10 N/m. Since the deflection is monitored with a precision better 0.1 nm, one typically obtains a force resolution of 1−100 pN. The separation distance can be obtained from the displacement of the scanner and the cantilever deflection Figure below illustrates how the cantilever responds to different force profiles. In the case of a soft repulsive force, the cantilever is repelled from the surface and only slowly approaches the constant compliance region. In such situations, it might be actually difficult to identify this region correctly. When the force is attractive, the cantilever is attracted to the surface and may become unstable. From stability considerations one finds that the cantilever will be unstable provided This instability is illustrated in the right panel of the figure on the right. As the cantilever approaches, the slope of the force curve increases. When the slope becomes larger than the spring constant of the cantilever, the cantilever jumps into contact when the slope of the force curve exceeds the force constant of the cantilever. Upon retraction, the same phenomenon happens, but the point where the cantilever jumps out is reached at a smaller separation. Upon approach and retraction, the system will show a hysteresis. In such situations, a part of the force profile cannot be probed. However, this problem can be avoided by using a stiffer cantilever, albeit at the expense of an inferior force resolution
|
https://en.wikipedia.org/wiki?curid=37605500
|
Colloidal probe technique The colloidal probes are normally fabricated by gluing a colloidal particle to a tip-less cantilever with a micromanipulator in air. The subsequent rewetting of the probe may lead to the formation of nanosized bubbles on the probe surface. This problem can be avoided by attaching the colloidal particles under wet conditions in AFM fluid cell to appropriately functionalized cantilevers. While the colloidal probe technique is mostly utilized in the sphere-plane geometry, it can be also used in the sphere-sphere geometry. The latter geometry further requires a lateral centering of the two particles, which can be either achieved with an optical microscope or an AFM scan. The results obtained in these two different geometries can be related with the Derjaguin approximation. The force measurements rely on an accurate value of the spring constant of the cantilever. This spring constant can be measured by different techniques. The "thermal noise" method is the simplest to use, as it is implemented on most AFMs. This approach relies on the determination of the mean square amplitude of the cantilever displacement due to spontaneous thermal fluctuations. This quantity is related to the spring constant by means of the equipartition theorem. In the "added mass method" one attaches a series of metal beads to the cantilever and each case one determines the resonance frequency. By exploiting the relation for a harmonic oscillator between the resonance frequency and the mass added one can evaluate the spring constant as well
|
https://en.wikipedia.org/wiki?curid=37605500
|
Colloidal probe technique The "frictional force method" relies on measurement of the approach and retract curves of the cantilever through a viscous fluid. Since the hydrodynamic drag of a sphere close to a planar substrate is known theoretically, the spring constant of the cantilever can be deduced. The "geometrical method" exploits relations between the geometry of the cantilever and its elastic properties. The separation is normally measured from the onset of the constant compliance region. While the relative surface separation can be determined with a resolution of 0.1 nm or better, the absolute surface separation is obtained from the onset of the constant compliance region. While this onset can be determined for solid samples with a precision between 0.5–2 nm, the location of this onset can be problematic for soft repulsive interactions and for deformable surfaces. For this reason, techniques have been developed to measure the surface separation independently (e.g., total internal reflection microscopy, reflection interference contrast microscopy). By scanning the sample with the colloidal probe laterally permits to exploit friction forces between the probe and the substrate. Since this technique exploits the torsion of the cantilever, to obtain quantitative data the torsional spring constant of the cantilever must be determined. A related technique involving similar type of force measurements with the AFM is the single molecular force spectroscopy
|
https://en.wikipedia.org/wiki?curid=37605500
|
Colloidal probe technique However, this technique uses a regular AFM tip to which a single polymer molecule is attached. From the retraction part of the force curve, one can obtain information about stretching of the polymer or its peeling from the surface.
|
https://en.wikipedia.org/wiki?curid=37605500
|
Anton Eleutherius Sauter (18 April 1800 in Grossarl – 1881 in Salzburg) was an Austrian physician and botanist. From 1820 to 1826 he studied medicine at the University of Vienna, where one of his instructors was Joseph Franz von Jacquin. After graduation, he worked as a physician at several locations in Austria. In 1840 he settled as a physician in Steyr, then from 1848 to 1871, served as a regional and district doctor in Salzburg. He is largely known for his investigations of flora native to Land Salzburg. From 1866 to 1879 he published in seven volumes, ""Flora des Herzogthums Salzburg"" (Flora of the Duchy of Salzburg}. In 1860 he was co-founder of the "Gesellschaft für Salzburger Landeskunde" (board member, 1864-74). Numerous taxa with the specific epithet of "sauteri" are named after him, an example being "Draba sauteri".
|
https://en.wikipedia.org/wiki?curid=37611255
|
Ping Tao Li (; born 1936) is a Chinese botanist who co-authored articles in the "Flora of China".
|
https://en.wikipedia.org/wiki?curid=37618233
|
Jiangshanian The is the middle stage of the Furongian series. It follows the Paibian stage and is succeeded by the still unnamed Stage 10 of the Cambrian. The base is defined as the first appearance of the trilobite "Agnostotes orientalis" which is estimated to be million years ago. The lasted until approximately million years ago. The Cambrian stage was named after Jiangshan, a city in China's Zhejiang province. The GSSP of the is the "Duibian B Section" (), west of the village of Duibian, and 10 km north of Jiangshan. The outcrop belongs to the Huayansi Formation.
|
https://en.wikipedia.org/wiki?curid=37618721
|
Guzhangian The is an uppermost stage of the Miaolingian Series of the Cambrian. It follows the Drumian Stage and precedes the Paibian Stage of the Furongian Series. The base is defined as the first appearance of the trilobite "Lejopyge laevigata" around million years ago. The Guzhangian-Paibian boundary is marked by the first appearance of the trilobite "Glyptagnostus reticulatus" around million years ago. The name is derived from Guzhang County in Hunan Province of China. The GSSP is defined in the Huaqiao Formation in Hunan, China. The precise base of the is a limestone layer 121.3 m above the base Huaqiao Formation at the Louyixi section (), where "Lejopyge laevigata" has its first appearance.
|
https://en.wikipedia.org/wiki?curid=37620670
|
Drumian The is a stage of the Miaolingian Series of the Cambrian. It succeeds the Wuliuan and precedes the Guzhangian. The base is defined as the first appearance of the trilobite "Ptychagnostus atavus" around million years ago. The top is defined as the first appearance of another trilobite "Lejopyge laevigata" around million years ago. The GSSP is defined in the "section" () in the Drum Mountains, Millard County, Utah, United States. The stage was also named after the Drum Mountains. The section is an outcrop of the Wheeler Formation, a succession of calcareous shales. The precise base of the is a laminated limestone above the base of the Wheeler Formation.
|
https://en.wikipedia.org/wiki?curid=37620824
|
Quantasome Quantasomes are particles found in the thylakoid membrane of chloroplasts in which photosynthesis takes place. They are embedded in a paracrystalline array on the surface of thylakoid discs in chloroplasts. They are composed of lipids and proteins that include various photosynthetic pigments and redox carriers. For this reason they are considered to be photosynthetic units. They occur in 2 sizes: the smaller quantasome is thought to represent the site of photosystem I, the larger to represent the site of photosystem II. Quantasomes were first identified by Roderic B. Park in 1962.
|
https://en.wikipedia.org/wiki?curid=37630226
|
Edison Volta Prize The is awarded biennially by the European Physical Society (EPS) to individuals or groups of up to three people in recognition of outstanding achievements in physics. The award consists of a diploma, a medal, and 10,000 euros in prize money. The award has been established in 2012 by the Centro di Cultura Scientifica "Alessandro Volta", Edison S.p.A and the European Physical Society. The 2018 EPS was awarded to : for "for the development, in their respective countries, of key technologies and innovative experimental solutions, that enabled the advanced interferometric gravitational wave detectors LIGO and Virgo to detect the first gravitational wave signals from mergers of Black Holes and of Neutron Stars" 2016 - The 2016 EPS was awarded to for "seminal contributions to optical science, to the field of single-molecule spectroscopy and imaging (first single molecule detection by fluorescence and first optical detection of magnetic resonance in single molecule) and for pioneering investigations into the photoblinking and photobleaching behaviors of individual molecules at the heart of many current optical super-resolution experiments
|
https://en.wikipedia.org/wiki?curid=37641022
|
Edison Volta Prize " The 2015 EPS has been awarded to the three principal scientific leaders of the European Space Agency’s (ESA) Planck Mission: "for directing the development of the Planck payload and the analysis of its data, resulting in the refinement of our knowledge of the temperature fluctuations in the Cosmic Microwave Background as a vastly improved tool for doing precision cosmology at unprecedented levels of accuracy, and consolidating our understanding of the very early universe. " 2014 EPS was awarded to: "for seminal contribution to physics (that) have paved the way for novel explorations of quantum mechanics and have opened new routes in quantum information processing" 2012 EPS was awarded 12 November 2012 to: "for having led, building on decades of dedicated work by their predecessors, the culminating efforts in the direction, research and operation of the CERN Large Hadron Collider (LHC), which resulted in many significant advances in high energy particle physics, in particular, the first evidence of a Higgs-like boson in July 2012".
|
https://en.wikipedia.org/wiki?curid=37641022
|
Misty Montes The are a range of mountains on Titan, the largest moon of the planet Saturn. The range is located in the northern hemisphere of Titan, between 56-7° north and 61-3° west. The are named after the Misty Mountains, a range of mountains in J. R. R. Tolkien's fictional world of Middle Earth which appears most prominently in "The Hobbit". The name follows a convention that Titanean mountains are named after mountains in Tolkien's work. It was formally announced on November 13, 2012.
|
https://en.wikipedia.org/wiki?curid=37642169
|
Irensaga Montes The is a range of mountains on Titan, the largest moon of the planet Saturn. The range is located near Titan's equator, between 5-6° south and 210-214° east. It is located within the Adiri region, just west of the landing site of the Huygens probe. The is named after Irensaga, one of the White Mountains in J. R. R. Tolkien's fictional world of Middle-earth. The name follows a convention that Titanean mountains are after mountains in Tolkien's work. It was formally announced on November 13, 2012.
|
https://en.wikipedia.org/wiki?curid=37642238
|
Mindolluin Montes The are a range of mountains on Titan, the largest moon of the planet Saturn. The range is located near Titan's equator, between 1-4° south and 205-213° east. It is located within the Adiri region, just west of the landing site of the Huygens probe. The are named after Mindolluin, one of the White Mountains in J. R. R. Tolkien's fictional world of Middle-earth. The name follows a convention that Titanean mountains are after mountains in Tolkien's work. It was formally announced on November 13, 2012.
|
https://en.wikipedia.org/wiki?curid=37642273
|
Mithrim Montes The are a range of mountains on Titan, the largest moon of the planet Saturn. The range is located near Titan's equator, between 1-3° south and 126-8° west and consists of three parallel ridges that are oriented east-west, spaced about 25 km apart. They are located within the region Xanadu. The highest peak is about high and is located on the southernmost of the ridges; it is the highest known peak on Titan. The are named after the Mithrim Mountains, a range in J. R. R. Tolkien's fictional world of Middle-earth. This follows a convention that Titanean mountains are named after mountains in Tolkien's work. The name was formally announced on November 13, 2012.
|
https://en.wikipedia.org/wiki?curid=37642334
|
Taniquetil Montes The are a range of mountains on Titan, the largest moon of the planet Saturn. The range is located near Titan's equator, between 2-4° south and 211-214° west. It is located within the Adiri region, just west of the landing site of the Huygens probe. The are named after Taniquetil, a mountain in the Undying Lands in J. R. R. Tolkien's fictional universe. The name follows a convention that Titanean mountains are named after mountains in Tolkien's work. It was formally announced on November 13, 2012.
|
https://en.wikipedia.org/wiki?curid=37642368
|
Erebor Mons is a mountain on Titan, the largest moon of the planet Saturn. It is located near Titan's equator, between 4-5° south and 35-36° west, centered on , in the western part of Quivira region. It is 40 km across, more than 1 km high and has lobate flow features to its north and east. It is probably a cryovolcano. is situated about 470 km to the north-northeast of a larger cryovolcanic construct, Doom Mons. is one of the highest known mountains of Titan, but it is not readily discernible on radar or infrared images. It was discovered only when stereoscopic radar data allowed construction of an elevation map. It was imaged by Cassini radar 22 February and 10 April 2007. is named after Erebor, the "Lonely Mountain" that appears in J. R. R. Tolkien's fictional world of Middle-earth, most prominently in "The Hobbit". The name follows a convention that Titanean mountains are named after mountains in Tolkien's work. The name was formally announced on November 13, 2012.
|
https://en.wikipedia.org/wiki?curid=37642436
|
Arrakis Planitia is a planitia (plain) on Titan, the largest moon of the planet Saturn. It is located in Titan's southern hemisphere, between 74-80° south and 113-134° east, within the Mezzoramia region. is named after Arrakis, a fictional desert planet that is featured prominently in Frank Herbert's "Dune" novels. The name follows a convention that Titanean plains are named after planets in Herbert's work.
|
https://en.wikipedia.org/wiki?curid=37642502
|
Substellar companion is a generic term for an astronomical body orbiting a star. It can describe a celestial bodies too small to be a star, but too big to be called a planet. Alternatively, it is a substellar object such as exoplanet or brown dwarf that is orbiting a star. Objects as low as 8-23 Jupiter masses have been called a substellar companion. Objects orbiting a star are often called a planet below 13 Jupiter masses and brown dwarf above that. Companions at that planet-brown dwarf borderline have been called Super-Jupiters, such around the star Kappa Andromedae. Nevertheless, objects as small as 8 Jupiter masses have been called a brown dwarf. A substellar companion is thought to exist in the binary star system SDSS 1212. Substellar companions have been confirmed by analyzing astrometric data from Hipparcos.
|
https://en.wikipedia.org/wiki?curid=37643310
|
Cooperative luminescence and cooperative absorption Cooperative luminescence is the radiative process in which two excited ions simultaneously make downward transition to emit one photon with the sum of their excitation energies. The inverse process is cooperative absorption, in which a photon can be absorbed by a coupled pair of two ions, making them excited simultaneously.
|
https://en.wikipedia.org/wiki?curid=37648306
|
Adaptive Coloration in Animals is a 500-page textbook about camouflage, warning coloration and mimicry by the Cambridge zoologist Hugh Cott, first published during the Second World War in 1940; the book sold widely and made him famous. The book's general method is to present a wide range of examples from across the animal kingdom of each type of coloration, including marine invertebrates and fishes as well as terrestrial insects, amphibians, reptiles, birds and mammals. The examples are supported by many of Cott's own drawings, diagrams, and photographs. This essentially descriptive natural history treatment is supplemented with accounts of experiments by Cott and others. The book had few precedents, but to some extent follows (and criticises) Abbott Handerson Thayer's 1909 "Concealing-Coloration in the Animal Kingdom". The book is divided into three parts: concealment, advertisement, and disguise. Part 1, concealment, covers the methods of camouflage, which are colour resemblance, countershading, disruptive coloration, and shadow elimination. The effectiveness of these, arguments for and against them, and experimental evidence, are described. Part 2, advertisement, covers the methods of becoming conspicuous, especially for warning displays in aposematic animals. Examples are chosen from mammals, insects, reptiles and marine animals, and empirical evidence from feeding experiments with toads is presented
|
https://en.wikipedia.org/wiki?curid=37658639
|
Adaptive Coloration in Animals Part 3, disguise, covers methods of mimicry that provide camouflage, as when animals resemble leaves or twigs, and markings and displays that help to deflect attack or to deceive predators with deimatic displays. Both Batesian mimicry and Müllerian mimicry are treated as adaptive resemblance, much like camouflage, while a chapter is devoted to the mimicry and behaviour of the cuckoo. The concluding chapter admits that the book's force is cumulative, consisting of many small steps of reasoning, and being a wartime book, compares animal to military camouflage. Cott's textbook was at once well received, being admired both by zoologists and naturalists and among allied soldiers. Many officers carried a copy of the book with them in the field. Since the war it has formed the basis for experimental investigation of camouflage, while its breadth of coverage and accuracy have ensured that it remains frequently cited in scientific papers. "Adaptive Coloration in Animals" is a 500-page book, in its first edition. It was published by Methuen (in London) and Oxford University Press (in New York) in 1940. It is full of detailed observations of types of camouflage and other uses of colour in animals, and illustrated by the author with clear drawings and photographs. There is a coloured frontispiece showing eight of Cott's paintings of tropical amphibians. The book has 48 monotone plates and several illustrations
|
https://en.wikipedia.org/wiki?curid=37658639
|
Adaptive Coloration in Animals Cott's method is to provide a large number of examples, illustrated with his own drawings or photographs, showing animals from different groups including fish, reptiles, birds and insects, especially butterflies. The examples are chosen to illustrate specific adaptations. For example, the fish "Chaetodon capistratus" is described as follows: Cott was well aware that he was publishing in wartime. There are, as Julian Huxley remarks in his 'Introduction', references throughout the book to the human analogues of animal camouflage and concealment. For example, in the section on 'Adaptive Silence', the kestrel is said to "practise dive-bombing attacks", or "after the fashion of a fighter 'plane" to fly down other birds, while "Owls have solved the problem of the silent air-raid"; Cott spends the rest of that paragraph on the "method which has recently been rediscovered and put into practice" of shutting off a bomber's engines and "gliding noiselessly down towards their victims" at Barcelona in the Spanish Civil War. In the concluding chapter, Cott explicitly states "The innumerable visible devices used ... in peacetime and in wartime ... are merely rediscovered ... applications of colour that have already reached a high ... degree of specialization and perfection.. in the animal world", mentioning predator-prey relationships, sexual selection and signalling to rivals. He then compares the "hunting disguises put on ..
|
https://en.wikipedia.org/wiki?curid=37658639
|
Adaptive Coloration in Animals as a means of approaching, ambushing or alluring game, and the sniping suits, concealed machine-gun posts, and booby traps" with the camouflage of animal predators; and similarly he compares "protective disguises" with the "photographer's hide and the gunner's observation post." In the same section, Cott compares intentionally visible signs with animal warning colours: "The policeman's white gloves have their parallel in the white stripes or spots of nocturnal skunks and carabids. The Automobile Association has adopted a system of coloration <nowiki>[black and yellow]</nowiki> whose copyright belongs by priority to wasps and salamanders." The book addresses its subject under three main headings: concealment, advertisement, and disguise. Cott sets out his view that we have to be re-taught how to see, mentioning Ruskin's "innocence of the eye". He argues that camouflage should, and in animals actually does, use four mechanisms: colour resemblance, obliterative shading (i.e. countershading, the graded shading which conceals self-shadowing of the lower body), disruptive coloration, and shadow elimination. Chapter 1. General colour resemblance. Chapter 2. Variable colour resemblance. Caterpillars and pupae (as in Poulton's famous experiment) are coloured to match their environment. Mountain hares change colour in winter; many fish, cephalopods, frogs, and crustacea can change colour rapidly. Chapter 3. Obliterative shading. Chapter 4. Disruptive coloration
|
https://en.wikipedia.org/wiki?curid=37658639
|
Adaptive Coloration in Animals Cott goes on to explain that the right-hand drawing shows the effect "of broken surroundings in further blending and confusing the picture", observing that this is the closest to what is seen in nature. His readers are invited to look first at the right-hand images to gain an idea of the power of "these optical devices" as camouflage, putting off the moment when the animal is actually recognised. Chapter 5. Coincident disruptive coloration. Chapter 6. Concealment Of the shadow. Chapter 7. Concealment in defence, mainly as illustrated by birds. Chapter 8. Concealment In offence. Chapter 9. Objections and evidence bearing on the theory of concealing coloration. Chapter 10. The effectiveness of concealing coloration. Chapter 1. The appearance and behaviour of aposematic animals. Chapter 2. Warning displays. Chapter 3. Adventitious warning coloration. Chapter 4. The nature and function of warning coloration, as illustrated by the mammalia. Chapter 5. The Protective Attributes Of Aposematic Animals In General. Chapter 6. The relation between warning colours and distasteful attributes. Chapter 7. The effectiveness of protective attributes associated with warning colours. Chapter 8. Experimental evidence that vertebrate enemies learn by experience. Chapter 9. Evidence of selective feeding by vertebrate enemies in a state of nature. Chapter 1. Special resemblance to particular objects. Chapter 2. Adaptive behaviour in relation to special cryptic resemblance. Chapter 3. Adventitious Concealing Coloration. Chapter 4
|
https://en.wikipedia.org/wiki?curid=37658639
|
Adaptive Coloration in Animals Deflective marks. Chapter 5. Directive marks. Chapter 6. Alluring coloration. Chapter 7. Mimicry: the attributes of mimics. Chapter 8. Breeding parasitism and mimicry in cuckoos. The final chapter confirms that "The force of the facts and arguments used in this work is cumulative in effect." Many small steps of reasoning combine to show that "adaptive coloration... has been... one of the main achievements of organic evolution." The book ends by comparing human artefacts and "natural adaptations", both of which can have goals (recall the publication date of 1940, early in the Second World War) including "the frustration of a predatory animal or of an aggressive Power". Julian S. Huxley wrote a foreword (labelled 'Introduction') which defends the Darwinian concept of adaptation, especially of colour (in animals) and within that frame of mimicry. He makes it clear that "in these last thirty years" (that is, from about 1910 to 1940) he believed that "experimental biologists" professed, even if they did not actually hold, "a radical scepticism on the subject of adaptations", in other words about whether natural selection really could have created the enormous diversity of pattern and colour seen in nature. Huxley quoted the now long-forgotten Aaron Franklin Shull's 1936 "Evolution" which stated "These special forms <nowiki>[</nowiki>sexual selection, warning colours, mimicry and signalling<nowiki>]</nowiki> of the selection idea..
|
https://en.wikipedia.org/wiki?curid=37658639
|
Adaptive Coloration in Animals seem destined to be dropped, or at least relegated to very minor places in the Evolution discussion.", and more sharply that "aggressive and alluring resemblance" (Huxley's words) "must probably be set down as products of fancy belonging to uncritical times." Huxley's reply is simply With objections dismissed, Huxley remarks that "Dr. Cott is a true follower of Darwin in driving his conclusions home by sheer weight of example," observing that "Faced with his long lists of demonstrative cases, the reader is tempted to wonder why adaptive theories of coloration have been singled out for attack by anti-selectionists." Huxley also noted Cott's "constant cross-reference to human affairs", and that it was good to know that Cott was applying his principles "to the practice of camouflage in war". Huxley concluded his introduction by describing "Adaptive Coloration" as "in many respects the last word on the subject", upholding the great tradition of "scientific natural history". Reviewers had little to compare "Adaptive Coloration" with
|
https://en.wikipedia.org/wiki?curid=37658639
|
Adaptive Coloration in Animals The English zoologist Edward Bagnall Poulton, a Darwinian, had written a 360-page book, "The Colours of Animals", fifty years earlier in 1890, and he was able, at age 84, to review Cott's work in "Nature" on its appearance in 1940, beginning with the words The ichthyologist Carl Leavitt Hubbs, reviewing the book for "American Naturalist" in 1942, began Hubbs notes that Cott is seeming concerned about the scarcity of experimental data for the survival value of camouflage, and accordingly relies on Sumner and Isely's "clear-cut results", but at once continues that Cott relies on "the general lore of natural history". Hubbs also remarks on the "resurgence to Darwinian views", referring to the scepticism about the power of natural selection among both geneticists of the time and to the Lamarckist views of Trofim Lysenko. Hubbs observes that Cott is both an artist and a naturalist as well as a scientist: "In section after section, rivaling one another in fascination, this master of art and of natural history unfolds the biological significance of adaptive coloration in animals." And Cott's emphasis on disruptive patterning and (following Thayer) countershading clearly affected the reviewer: "Particularly impressive is the author's treatment of "coincident disruptive coloration", in which a ruptive mark crosses structural boundaries, so as to obliterate visually such ordinarily conspicuous parts as the eye and the limbs. Concealment of an animal's ordinarily telltale shadow is also stressed"
|
https://en.wikipedia.org/wiki?curid=37658639
|
Adaptive Coloration in Animals Hubbs's review ends "This book is the work of an artist, and it is a work of art. Every biologist with an interest in any phase of natural history or evolution should keep it at hand." "W.L.S.", reviewing Cott in The Geographical Journal in 1940, begins with "In this large and well-illustrated volume the author discusses at length reason or reasons for the various colour patterns found in the animal kingdom." The reviewer goes on "He has presented us with a vast number of facts and observations which are somewhat difficult to analyse." However "W.L.S." admits that disruptive coloration "is discussed at considerable length by Mr. Cott and many remarkable instances of it are considered in detail". The review ends by mentioning that while biologists (of the 1930s) usually "reject the influence of Natural Selection in evolution, the facts of adaptive coloration as given in Mr. Cott's work are a strong argument in its favour, and must be given due weight. This is what Mr. Cott claims to have accomplished in a volume which will certainly take its place as a most valuable contribution to zoological literature." Peter Forbes, in his book "Dazzled and Deceived", wrote that Over 60 years after its publication, "Adaptive Coloration in Animals" remains a core reference on the subject
|
https://en.wikipedia.org/wiki?curid=37658639
|
Adaptive Coloration in Animals Sören Nylin and colleagues observe in a 2001 paper that As a natural history narrative on what has become an intensely researched experimental subject, "Adaptive Coloration" could be thought obsolete, but instead, Peter Forbes observes "But Cott's book is still valuable today for its enormous range, for its passionate exposition of the theories of mimicry and camouflage". This width of coverage and continuing relevance can be seen in the introduction to Sami Merilaita and Johan Lind's 2005 paper on camouflage, "Background-Matching and Disruptive Coloration, and the Evolution of Cryptic Coloration", which cites "Adaptive Coloration" no fewer than eight times, quoting his terms "cryptic coloration or camouflage", "concealing coloration", "background matching (also called cryptic resemblance)", "disruptive coloration", resemblance to visual background, and the difficulty a predator has to detect a prey visually. Steven Vogel, in a review of Peter Forbes's book "Dazzled and Deceived" (2009), echoes Julian Huxley's words of seventy years before (in his 'Introduction') by writing Camouflage researcher Roy Behrens cites and discusses "Adaptive Coloration" frequently in his writings. For example, in his "Camoupedia" blog, related to the book of the same name, he writes of Cott's drawings of the hind limbs of the Common frog: "Reproduced above is one of my favorite drawings from what is one of my favorite books
|
https://en.wikipedia.org/wiki?curid=37658639
|
Adaptive Coloration in Animals " He continues "What makes these drawings (and the book itself) even more interesting is that Cott (1900-1987) was not just a zoologist—he was a highly skilled scientific illustrator (these are his own pen-and-ink drawings), a wildlife photographer, and a prominent British camoufleur in World War II." Still in 2011, Behrens can write of Cott's way of thinking, citing his words as models of clear and accurate explanation of the mechanisms of camouflage: "As he so aptly explained it, disruptive patterns work 'by the optical destruction of what is present', while continuous patterns work 'by the optical construction of what is not present.'" "Adaptive Coloration in Animals" has been published as follows:
|
https://en.wikipedia.org/wiki?curid=37658639
|
SXDF-NB1006-2 is a distant galaxy located in the Cetus constellation, with a spectroscopic redshift of "z" = 7.213 or 12.91 billion light-years away. It was discovered by the Subaru XMM-Newton Deep Survey Field. The galaxy was claimed to be the most distant galaxy at announcement in June 2012, as the more distant claimants were not confirmed spectroscopically at the time. It exceeded the previous confirmed distance holder, GN-108036, also discovered by the Subaru. It contains the oldest oxygen in the Universe
|
https://en.wikipedia.org/wiki?curid=37661603
|
MACS J0647.7+7015 is a galaxy cluster with a redshift "z" = 0.592, located at J2000.0 right ascension declination . It lies between the Big Dipper and Little Dipper in the constellation Camelopardalis. It is part of a sample of 12 extreme galaxy clusters at "z" > 0.5 discovered by the MAssive Cluster Survey (MACS). During 2012 the galaxy cluster was announced as gravitationally lensing the most distant galaxy (MACS0647-JD), then ever imaged ("z" = 11).
|
https://en.wikipedia.org/wiki?curid=37678417
|
MAssive Cluster Survey The (MACS) compiled and characterized a sample of very X-ray luminous (and thus, by inference, massive), distant clusters of galaxies. The sample comprises 124 spectroscopically confirmed clusters at 0.3 < z < 0.7. Candidates were selected from the ROSAT All-Sky Survey data. One of the galaxy clusters, MACS J0647+7015 was found to have gravitationally lensed the most distant galaxy (MACS0647-JD) then ever imaged, in 2012, by CLASH. The first statistical study of X-ray cavities in distant clusters of galaxies was performed by analyzing the Chandra X-ray observations of MACS. Out of 76 clusters representing a sample of the most luminous X-ray clusters, observers found 13 cut and clear cavities and 7 possible cavities. A new radio halo, as well as a relic applicant, were found in MACS, with the help of the Giant Meterwave Radio Telescope and the Karoo Array Telescope-7. The discovered radio halo has a largest linear scale of about 0.9Mpc. X-ray chosen clusters are almost free of projection effects because they are composed of intrinsically massive, gravitationally collapsed systems. The MACS team consists of: Objects are labelled as JHHMM.m+DDMM where HHMM+DDMM are the coordinates in the J2000 system. Here H, D, and M refer to hours, degrees, and minutes, respectively, and m refers to tenths of minutes of time. I am going to use these sources to add information to this page. http://mnras.oxfordjournals.org/content/407/1/83.short http://mnras.oxfordjournals.org/content/421/2/1360.short http://mnras.oxfordjournals
|
https://en.wikipedia.org/wiki?curid=37679288
|
MAssive Cluster Survey org/content/458/2/1803.abstract
|
https://en.wikipedia.org/wiki?curid=37679288
|
The Colours of Animals is a zoology book written in 1890 by Sir Edward Bagnall Poulton (1856–1943). It was the first substantial textbook to argue the case for Darwinian selection applying to all aspects of animal coloration. The book also pioneered the concept of frequency-dependent selection and introduced the term "aposematism". The book begins with a brief account of the physical causes of animal coloration. The second chapter gives an overview of the book, describing the various uses of colour in terms of the advantages it can bring through natural selection. The next seven chapters describe camouflage, both in predators and in prey. Methods of camouflage covered include background matching, resemblance to specific objects such as bird droppings, self-decoration with materials from the environment, and the seasonal colour change of arctic animals. Two chapters cover warning colours, including both Batesian mimicry, where the mimic is edible, and Mullerian mimicry, where distasteful species mimic each other. A chapter then looks at how animals combine multiple methods of defence, for instance in the puss moth. Two chapters examine coloration related to sexual selection. Finally Poulton summarizes the subject with a fold-out table including a set of Greek derived words that he invented, of which "aposematic" and "cryptic" survive in biological usage
|
https://en.wikipedia.org/wiki?curid=37696632
|
The Colours of Animals "The Colours of Animals" was well received on its publication, although the book's support for sexual selection was criticised by Alfred Russel Wallace, and its Darwinism and critique of Lamarckism were attacked by Edward Drinker Cope. Wallace liked Poulton's experimental work but was critical of his opinions on sexual selection. The Neo-Lamarckian Cope criticised Poulton's support for Darwin but liked the book's many observations of animal coloration. Modern biologists respect Poulton's advocacy of natural selection and sexual selection, despite the lack at the time of an adequate theory of heredity, and his recognition of frequency-dependent selection
|
https://en.wikipedia.org/wiki?curid=37696632
|
The Colours of Animals Poulton explains in his Preface that Poulton strongly supports Darwin both on the general theme of natural selection, and on the power of sexual selection in species which are sexually dimorphic (where, usually, the male is showier than the female): Poulton knew his view was controversial, but believed he was winning the argument: In "The Colours of Animals", Poulton introduced the concept of frequency-dependent selection (selection based on how abundant a form is) in the context of a polymorphism which he argued would otherwise soon vanish: The basic concept of warning coloration (aposematism, like the black and yellow pattern of a wasp) is approached very simply: In the next paragraph Poulton ties aposematism to mimicry as follows: Poulton introduced the term "aposematism" with the words: The book's structure emphasises the extent to which Poulton, like Darwin, relied on a mass of evidence, mainly from insects, to make his case: Chapter 1 The Physical Cause of Animal Colours. Chapter 2 The Uses of Colour. Chapter 3 Protective Resemblances in Lepidoptera. Chapter 4 Protective Resemblances in Lepidoptera (continued), Dimorphism, Etc. Chapter 5 Protective Resemblances In Vertebrata, Etc. Chapter 6 Aggressive Resemblances — Adventitious Protection. Chapter 7 Variable Protective Resemblance in Vertebrata, Etc. Chapter 8 Variable Protective Resemblance In Insects. Chapter 9 Protective Resemblances in Lepidoptera (continued). Chapter 10 Warning Colours. Chapter 11 Warning Colours (continued)
|
https://en.wikipedia.org/wiki?curid=37696632
|
The Colours of Animals Chapter 12 Protective Mimicry. Chapter 13 Protective and Aggressive Mimicry. Chapter 14 The Combination of Many Methods of Defence. Chapter 15 Colours Produced by Courtship. Chapter 16 Other Theories of Sexual Colouring. Chapter 17 Summary And Classification. The co-discoverer of natural selection Alfred Russel Wallace, reviewing Poulton in "Nature", was interested by Poulton's observations on thin films producing iridescence: "In some cases dried insects lose some of their metallic colours, but these reappear when the specimen is dipped in water." However, Wallace objected to Poulton's suggestion that arctic birds and mammals are white to reduce heat loss by radiation, for which he argued there was no evidence in favour, while a thicker "covering, such as actually occurs in all arctic animals" would reduce heat loss effectively, and could be observed to do so. Wallace was enthusiastic about Poulton's experimental work on how butterfly larvae vary their coloration according to the background, admiring "a number of ingenious experiments" in which Poulton illuminated the insects in light of one colour or another, causing reliable colour changes which could not be direct, like photography, but had to be mediated by the animal's nervous system: In some cases even the cocoons spun by the larvæ are modified by the surrounding colours; and still more curious changes are effected in the larva itself when ... the same species feeds on several plants having differently-coloured leaves
|
https://en.wikipedia.org/wiki?curid=37696632
|
The Colours of Animals Even the presence of numerous dark twigs has been shown to cause a corresponding change of colour in the larva of the peppered moth ("Amphidasis betularia")." Wallace's main criticism, occupying half his lengthy review, was of Poulton's acceptance of sexual selection. He begins by stating "Mr. Poulton fully accepts Darwin's theory of female choice as the source of the greater part of the brilliant colour, delicate patterns, and ornamental appendages that exist among animals, and especially among birds and insects." Wallace then cites Poulton on the courtship behaviour of spiders: "'The female always watches the antics of the male intently, but often refuses him in the end, 'even after dancing before her for a long time.' Such observations strongly point towards the existence of female preference based on æsthetic considerations'" at once objecting "To the last four words we demur, as being altogether unproved. Why æsthetic considerations?" Wallace then spends a whole page attacking Poulton on "the possession of an 'æsthetic sense' by those creatures in which sexual ornament occurs". Wallace objects that Poulton asserts the reality of sexual selection with no proof other than mentioning that insects can perceive colour, and that "a few birds collect bright objects, as in the case of the bower-birds"
|
https://en.wikipedia.org/wiki?curid=37696632
|
The Colours of Animals Wallace gives a detailed counter-example to refute Poulton's argument, arguing that "really beautiful combinations of colour and marking" are found on the sea shells of molluscs "where sexual selection has certainly not come into play". To make the point, Wallace lists "the cones, cowries, olives, harps, volutes, pectens, and innumerable other molluscan shells; while many of the sea-anemones, and considerable numbers of the caterpillars with warning colours, are equally beautiful." And that was not all. Wallace continued: "Still more doubtful and more opposed to reasonable probability is the statement that 'our standards of beauty are largely derived from the contemplation of the numerous examples around us, which... have been created by the æsthetic preferences of the insect world'--alluding... to the colours and structures of flowers as being due to the need of attracting insects to fertilize them." There was, Wallace insisted, "not a particle of evidence" of aesthetic preferences in "an insect's very limited mentality". The mention of the term aesthetic was "not scientific". After so many "preceding remarks" against "the theory of sexual selection", Wallace concludes that "The book is well illustrated by numerous excellent woodcuts and a coloured plate", congratulates Poulton on "having produced so readable and suggestive a volume", and on having "contributed so largely" by "his own researches" into animal coloration
|
https://en.wikipedia.org/wiki?curid=37696632
|
The Colours of Animals An anonymous reviewer in the "New York Times" wrote that "Mr Poulton wishes first of all to put himself right with regard to his attitude to Darwinism", mentioning that in 1888 he had been cited in the "Edinburgh Review" as attacking Darwinism. The reviewer hastens to agree that Poulton is in fact "ready to combat Wallace, his master, on points wherein that great fellow-laborer with Charles Darwin dissents from the latter's views." As an example of this, the reviewer mentions Poulton's argument that Wallace must be wrong that "the coloring whereby the sexes often differ one from the other in a startling way is occasioned by a surplus vitality" because "sexual colors are only developed in species which court by day or twilight" and then only on parts of the body which the female "would oftenest and best see them". The New York Times reviewer argued that the title should have been less general "for readers are sure to demand too much from so comprehensive a term", given that Poulton refers mainly to insects rather than "wild beasts", but in the end he agreed "that Mr. Poulton has written a very suggestive treatise, well fitted for the general reader". The Neo-Lamarckian Edward Drinker Cope, reviewing the book for the "American Naturalist", writes that "Mr. Poulton supports his own theory of the direct physiological value of the uses of colour to animals by a large amount of experimental evidence brought together from many sources"
|
https://en.wikipedia.org/wiki?curid=37696632
|
The Colours of Animals Cope is attracted by "a detail of great interest" in a caterpillar's camouflage "by the semblance of a small hole to indicate piercing by insect larvae" (ichneumon flies, since they avoid caterpillars that are already parasitised), and is impressed by Poulton's observations of "perhaps the most perfect concealment attained by any butterfly" in the dead leaf butterfly "Kallima", first described by Alfred Russel Wallace. While admiring of Poulton's detailed observations, Cope is critical of his support for Darwin, arguing that Poulton fails to explain how the variability that natural selection needs to work on actually arises. (The mechanisms of mutation and genetics were not to become adequately understood until the twentieth century rediscovery of Mendel's work.) Cope also objects to Poulton's critique of Lamarckism, where in a footnote he cites S.B.J. Skertchly as writing that "other butterflies "noticed this immunity [and] copied it", to which Cope replies as that "even the American Neo-Lamarckians [like Cope] do not follow their founder so far as to believe that the volition of an animal could account for all the details of mimetic resemblance." "Science" reviewed the book in November 1890. The reviewer remarks that "It is impossible in this brief notice to do full justice to the wealth of interesting examples with which the author presents us", and notes that unlike the "hackneyed" examples of mimicry and camouflage in other textbooks, "Many of the observations are original
|
https://en.wikipedia.org/wiki?curid=37696632
|
The Colours of Animals " The reviewer remarks, also, on the "decided antithesis between warning and protective colors", animals being either "as conspicuous as possible", or as cryptic as possible, while the conspicuous ones "are usually accompanied by a nauseating taste, strongly smelling or irritant fluids, etc." The reviewer notes more critically that additional examples of mimicry might have been given, such as of Hymenoptera (bees and wasps) mimicked by Diptera (flies), and would have liked fuller treatment of Bates's "South American heliconids and pierids". The reviewer finds the closing chapters on "colors used in courtship" the most interesting of the book, since zoologists disagreed widely on the subject, and notes that Poulton sided with Darwin and against Wallace "who denies that the so-called secondary sexual characters" can "owe their origin to sexual selection". The reviewer, siding with Poulton, writes that "It would be difficult, we believe, to explain many of the facts cited by Poulton, notably Peckham's observations on the courtship of spiders, from Wallace's standpoint." The review ends with a brief discussion of Poulton's table classifying animal coloration, predicting (correctly) that the "Greek derivatives" such as pseudaposematic and pseudepisematic will not be generally adopted. The "British Medical Journal" reviewed the book in July 1890
|
https://en.wikipedia.org/wiki?curid=37696632
|
The Colours of Animals The review begins by noting that the pre-Darwinian view of colour "to-day appears almost ridiculous", adding that "we now know" that colour is of benefit to the animal, and is subject to natural selection. The reviewer writes that it is among Lepidoptera (butterflies and moths) that "protective resemblance or 'cryptic coloration' is most beautifully illustrated, and the book teems with instances" of these, noting that Poulton had "made this part of the subject his own". The review quotes examples including the twig larvae of the Brimstone moth and the "terrifying attitude" of the Puss moth caterpillar. The reviewer, noting Wallace's different opinion, has no difficulty with Poulton's view of sexual selection, that it is "due to an aesthetic sense in the [female] animals", and likes Poulton's expression that "Natural Selection is a qualifying examination which must be passed by all candidates for honours; Sexual Selection is an honours examination in which many who have passed the previous examination will be rejected." The review objects to the "thick type headings to the subdivision of chapters" which it finds too much like "the 'new journalism'". It concludes by urging readers to compare the book with Darwin's "Descent of Man" and with Wallace's "Darwinism"
|
https://en.wikipedia.org/wiki?curid=37696632
|
The Colours of Animals Poulton was a staunch supporter of Darwin, through a period when there was no adequate theory of heredity and both natural selection and sexual selection had become unpopular among scientists, and was attacked for his support both in "The Colours of Animals" and outside it. And he is recognised as the first scientist to identify frequency-dependent selection, as described in this book. By 1919, the book was being described in "Nature" as a classic work. Poulton is paid homage by J.A. Allen and B.C. Clarke for his pioneering work on frequency-dependent selection "by predators acting on non-mimetic polymorphic prey (i.e. for apostatic selection), anticipating many of the points made by later workers. We draw attention to his remarkable insight." The "Oxford Dictionary of National Biography" comments that Poulton's book "concisely and simply explained the many forms of coloration in terms of natural selection; these forms he ingeniously summarized in a comparative table introducing terms which became the standard nomenclature." In her book "The Ant and the Peacock: Altruism and Sexual Selection from Darwin to Today", the Darwinian philosopher and rationalist Helena Cronin writes that in "The Colours of Animals", Poulton defended Darwin's theory of sexual selection, stressing the role of female choice
|
https://en.wikipedia.org/wiki?curid=37696632
|
The Colours of Animals She suggests that while people have therefore taken Poulton for a staunch Darwinist and supporter of sexual selection, he "lost his initial enthusiasm for the theory" and "came to relegate it to a very minor position" in evolution. She writes that Poulton's position was highly influential, stating that later "Darwinian experts on coloration" followed his views, citing Frank Evers Beddard's 1892 "Animal Coloration" as evidence. In his Introduction to Hugh Bamford Cott's 1940 book "Adaptive Coloration in Animals", Julian Huxley praised Cott's work as "a worthy successor to Sir Edward Poulton's "The Colours of Animals"... The one was a pioneer study, the other is in many respects the last word on the subject"".
|
https://en.wikipedia.org/wiki?curid=37696632
|
Cluster Lensing and Supernova survey with Hubble The Cluster Lensing And Supernova survey with Hubble (CLASH) was a program on the Hubble Space Telescope to observe 25 massive galaxy clusters. CLASH was one of three programs selected (along with CANDELS and PHAT) in the first class of Hubble multi-cycle treasury programs, which were designed to tackle large questions unanswerable through normal observations. Observations for CLASH were conducted between November 2010 and July 2013. CLASH was led by principal investigator Marc Postman, and had a science team of over 40 researchers. Primary observations for CLASH were conducted on the "Hubble Space Telescope" with the Advanced Camera for Surveys (ACS) and Wide Field Camera 3 (WFC3). Images were taken in 16 filters, which were selected to maximize the ability to detect distant galaxies behind each cluster. Twenty of the observed clusters were selected due to their relaxed morphology in X-ray observations, while the other five were chosen due to their strength as gravitational lenses. As of November 2012, the CLASH has surveyed 20 clusters out of the 25. One of the galaxy clusters, MACS J0647+7015 was found to have gravitationally lensed the most distant galaxy (MACS0647-JD) then ever imaged, in 2012. In 2013, one study utilizing CLASH data found that RX J1347.5-1145 had intense gravitational bending of light such that 8 images of the same object were detected. (See Gravitational lensing) List of clusters is:
|
https://en.wikipedia.org/wiki?curid=37699639
|
Charles George Johnson (188614 October 1950) was a chemist, businessman and political figure in Adelaide, South Australia. Johnson was born in Essex, England in 1886 and led an adventurous life, including a spell of boxing professionally, before arriving in Adelaide in 1925. He first came to public notice as a Labor Party (ALP) candidate for a North Adelaide seat in South Australia's House of Assembly in 1933. In August 1934, Johnson founded the cleaning products company Jasol Chemical Products. "Jasol" was an acronym for "Johnson's Antiseptic Soluble Oils Limited." Early deliveries were done by Johnson on a pushbike. In 1945, when he was well known for his association with the Jasol firm, Johnson was elected as Councillor on the Adelaide City Council. He resigned from the ALP in 1947. He consistently voted against generosity towards retiring councillors, mayors and employees, even when he acknowledged that the person had served the council exceptionally well. He resigned in 1949 to stand as an alderman but was defeated. He was vice-president of the Adelaide sub-branch of the Returned Sailors Soldiers and Airmens Imperial League of Australia. Johnson lived on South Terrace, Adelaide. He died in the Repatriation General Hospital, Daw Park in 1950. He was survived by his wife Millie Johnson.
|
https://en.wikipedia.org/wiki?curid=37700226
|
Abell 2261 is one of 25 galaxy clusters being studied as part of the Cluster Lensing And Supernova survey with Hubble (CLASH) program, a major project to build a library of scientific data on lensing clusters. It also has the galaxy A2261-BCG (short for Brightest Cluster Galaxy) which has the largest galaxy core ever observed.
|
https://en.wikipedia.org/wiki?curid=37701294
|
RX J1347.5−1145 RX J1347.5–1145 is one of the most massive galaxy clusters known. As a result, it is also one of the most X-ray-luminous because of its hot gas content. The object resides roughly 5 billion light-years away from the Solar System in the constellation of Virgo. Redshift was noted as z=0.451 with an X-ray luminosity of 10 ergs s in a paper from 2002. In 2013, one study found eight cases of the same object resulting from the intense gravitational bending of light. That study made use of data from Cluster Lensing and Supernova survey with Hubble (CLASH) as well as other sources.
|
https://en.wikipedia.org/wiki?curid=37701371
|
Global surface temperature In earth science, global surface temperature (GST) is calculated by averaging the temperature at the surface of the sea and air temperature over land. In technical writing, scientists call long-term changes in GST "global cooling" or "global warming". Periods of both have happened regularly throughout earth's history. Since the beginning of global temperatures in 1880 up to 1940, the average annual temperature has increased by 0.2 °C. The temperature was then stable between 1940 and 1970. And it has been increasing again since 1970 by 0.18 °C each decade. The average global temperature has increased by 0.9 °C (1.5 °F) compared to the baseline temperature which is about 14 °C. Although a pause has been observed between 1998 and 2013, the global warming continues since at the same pace as before. In the 1860s, physicist John Tyndall recognized the Earth's natural greenhouse effect and suggested that slight changes in the atmospheric composition could bring about climatic variations. In 1896, a seminal paper by Swedish scientist Svante Arrhenius first predicted that changes in the levels of carbon dioxide in the atmosphere could substantially alter the surface temperature through the greenhouse effect. Changes in global temperatures over the past century provide evidence for the effects of increasing greenhouse gasses. When the climate system reacts to such changes, climate change follows
|
https://en.wikipedia.org/wiki?curid=37719142
|
Global surface temperature Measurement of the GST is one of the many lines of evidence supporting the scientific consensus on climate change, which is that humans are causing warming of Earth's climate system. With the Earth's temperature increasing, the ocean have absorbed much of this increased heat, with the top 700 meters of ocean showing warming of 0.22 C (0.4°F) since 1969. Expansion of the warm water, along with melting ice sheets, causes the sea level to rise. The Antarctic and Greenland ice sheets have decreased exponentially in mass. According to NASA's Gravity Recovery and Climate Experiment, it shows that Greenland has lost an average of 286 billion tons of ice per year. Expansion of the warm water, along with melting ice sheets, causes the sea level to rise.
|
https://en.wikipedia.org/wiki?curid=37719142
|
Pieter Cornelius Tobias Snellen (30 August 1832 – 29 March 1911) was a Dutch entomologist. Pieter Snellen was a merchant in Rotterdam. He is not to be confused with Samuel Constantinus Snellen van Vollenhoven, another entomologist from Rotterdam.
|
https://en.wikipedia.org/wiki?curid=37721865
|
Murinus Cornelius Piepers Marinus Cornelius Piepers (1836 –1919, Den Haag) was a Dutch entomologist. He specialised in Lepidoptera and Coleoptera especially of the Dutch East Indies. His collection is conserved in Naturalis in Leiden. online at Biodiversity Heritage Library Four volumes.
|
https://en.wikipedia.org/wiki?curid=37722198
|
Concealing-Coloration in the Animal Kingdom "Concealing-Coloration in the Animal Kingdom: An Exposition of the Laws of Disguise Through Color and Pattern; Being a Summary of Abbott H. Thayer’s Discoveries" is a book published ostensibly by Gerald H. Thayer in 1909, and revised in 1918, but in fact a collaboration with and completion of his father Abbott Handerson Thayer's major work. The book, illustrated artistically by Abbott Thayer, sets out the controversial thesis that all animal coloration has the evolutionary purpose of camouflage. Thayer rejected Charles Darwin's theory of sexual selection, arguing in words and paintings that even such conspicuous animal features as the peacock's tail or the brilliant pink of flamingoes or roseate spoonbills were effective as camouflage in the right light. The book introduced the concepts of disruptive coloration to break up an object's outlines, of masquerade, as when a butterfly mimics a leaf, and especially of countershading, where an animal's tones make it appear flat by concealing its self-shadowing. The book was criticised by big game hunter and politician Theodore Roosevelt for its central assertion that every aspect of animal coloration is effective as camouflage. Roosevelt's detailed reply attacked the biased choice of examples to suit Abbott Thayer's thesis and the book's reliance on unsubstantiated claims in place of evidence
|
https://en.wikipedia.org/wiki?curid=37724748
|
Concealing-Coloration in the Animal Kingdom The book was more evenly criticised by zoologist and camouflage researcher Hugh Cott, who valued Thayer's work on countershading but regretted his overenthusiastic attempts to explain all animal coloration as camouflage. Thayer was mocked to a greater or lesser extent by other scientific reviewers. Abbott Thayer (1849–1921) was an American artist, known for his figure paintings, often of "virginal, spiritual beauty", which were sometimes, as in his most famous painting, "Angel", modeled on his children. He had studied at an art school in Paris, but unlike James McNeill Whistler he returned to the United States. Along with seeking timeless beauty, Thayer also became obsessed with nature, which he felt contained the pure beauty that he was seeking to capture in his paintings. Thayer's close observation led him to notice what scientists such as Edward Bagnall Poulton were just beginning to describe. This was that many animals were "painted" the opposite way to how painters create the appearance of solidity in figures. A canvas is flat, and areas of uniform color painted on a canvas also appear flat. To make a body appear to have depth and solidity, the artist paints in shadows on the body itself. The top of an animal's back, facing the sky, remains bright, while it must become darker towards its underside. Thayer was excited to realize that by reversing such shading, nature could and did make animals appear flat. He was so passionate about this "concealing coloration" theory that he called it his "second child"
|
https://en.wikipedia.org/wiki?curid=37724748
|
Concealing-Coloration in the Animal Kingdom Poulton had noticed countershading in certain caterpillars, but he had not realized that the phenomenon was widespread, and he championed Thayer's theory in a 1902 article in "Nature". However, Thayer was not a scientist, and he lacked a scientist's inclination to attempt to test and disprove every aspect of a new theory. Instead, Thayer came to believe that the theory belonged to artists, with their trained perception: "The whole basis of picture making consists in contrasting against its background every object in the picture", he argued. The obsession led him to deny that animals could be colored for other reasons: for protection by mimicry, as the naturalist Henry Walter Bates had proposed, supported by many examples of butterflies from South America; through sexual selection, as Charles Darwin had argued, again supported by many observations. The unbalanced treatment of animal coloration in "Concealing-Coloration in the Animal Kingdom" encapsulates Thayer's partial understanding and his rejection of other theories. The same obsession led him, later, to attempt to persuade the military to adopt camouflage based on his ideas, traveling to London in 1915, and writing "passionate letters" to the Assistant Secretary to the US Navy, Franklin Delano Roosevelt, in 1917. Gerald Thayer describes the book as having two main purposes: to present Abbott Thayer's research to naturalists; and to make the subject available to a wider readership
|
https://en.wikipedia.org/wiki?curid=37724748
|
Concealing-Coloration in the Animal Kingdom The book's list of contents reveals Thayer's heavy reliance on bird examples, filling 16 of the 27 chapters. Other vertebrates occupy 5 chapters. Insects receive 3 chapters, of which two are dedicated to lepidoptera - one to caterpillars, one to adult butterflies and moths; the remaining one devotes 14 pages to all other insects, starting with orthoptera including the leaf-mimic grasshoppers. The book has 16 colored plates of paintings by Abbott Thayer and Richard S. Meryman, including the well known frontispiece "Peacock amid foliage", and the heavily criticised images of wood ducks, blue jays against snow, roseate spoonbills and flamingoes "at dawn or sunset, and the skies they picture". The last 4 colored plates are of caterpillars. Gerald Thayer claims that "The illustrations are of particular importance, inasmuch as they include what we believe to be the first scientific paintings ever published of animals lighted as they actually are in nature". There are 140 black and white figures, mainly photographs with a few diagrams and drawings. Half the photographs are of birds. The photographs are from various sources, "gleaned from periodicals, or secured by special advertising." Chapter 1 sets out the "long-ignored laws" of "protective coloration", an act which "has waited for an artist" to perceive. Thayer explains the principle of countershading with a diagram, arguing that a naive view of being "colored like their surroundings" does not explain how animal camouflage works
|
https://en.wikipedia.org/wiki?curid=37724748
|
Concealing-Coloration in the Animal Kingdom He acknowledges the prior work of Edward Bagnall Poulton ("The Colours of Animals", 1890) in identifying countershading in caterpillars, quoting some passages where Poulton describes how larvae and pupae can appear flat. Countershading is named as "the law which underlies protective coloration", rather than as one of several principles. Chapter 2 defines the book's terms, equating "mimicry" with "protective resemblance", so that it becomes a form of "protective or disguising coloration". Thayer distinguishes "concealing-colors" (mainly countershading for "invisibility") from the "other" branch of protective coloration, which includes most kinds of mimicry, for "deceptive visibility". The two branches are then named "obliterative coloration" and "mimicry". Mimicry is dismissed as playing "a very insignificant part" in the "higher orders", i.e. it is limited mainly to invertebrates. A fine photograph of a "white fowl, lacking counter-shading, against a flat white cloth" demonstrates that camouflage is more than color matching. Thayer then gives several examples of what he considers countershaded animals. Chapter 3 describes the combination of markings with countershading, with photographs of a model bird and of a woodcock, showing how in the correct position these are well camouflaged with "wonderful obliterative picture-patterns", but wrongly positioned or upside down (with a photograph of a dead woodcock) they are easily visible
|
https://en.wikipedia.org/wiki?curid=37724748
|
Concealing-Coloration in the Animal Kingdom Chapters 4 and 5 illustrate more "picture-patterns" in well camouflaged birds including Wilson's snipe and whip-poor-will (nighthawks and goatsuckers, Caprimulgidae). Thayer describes these as showing "obliteration, or "merging with the background"" but that their patterning is close to mimicry as they "perfectly" resemble objects such as "a stone or mossy log". Chapter 6 argues that some birds such as the ruffed grouse have patterns designed as camouflage against distant backgrounds, with a painting of a bird against a forest background as evidence. "The bird is in plain sight, but invisible". For the great horned owl, a piece of the wing is "super-imposed" on a photograph of a wood, "to show how closely the owl's patterns reproduce such a forest interior." The text describes the owl as having "a highly developed forest-vista pattern". Chapter 7 similarly argues for grass and heather patterns on "terrestrial" (as opposed to arboreal) birds. The disruptively patterned white-tailed ptarmigan is shown in "a very remarkable photograph" by Evan Lewis. Thayer attempts to classify the camouflage types, for example writing Chapter 8 continues the theme with "scansorial" or tree climbing birds. Chapter 9 claims that "obliterative shading, pure and simple, is the rule among the Shore Birds" such as sandpipers and curlew
|
https://en.wikipedia.org/wiki?curid=37724748
|
Concealing-Coloration in the Animal Kingdom Chapter 10 describes the "background-picturing" of bitterns, birds which live in reedbeds, where Chapter 11 argues (in a way that was heavily criticised when the book appeared, see below) that water birds, some of them highly conspicuous like the jacana and notoriously the male wood duck, are colored for camouflage: "The beautifully contrasted black-and-white bars on the flanks of the Wood Duck ("Aix sponsa") are "ripple pictures", and as potent [as camouflage], in their place, as the most elaborate markings of land birds". Chapter 12 argues that the "pure white" of ocean birds such as gulls and terns equally functions as camouflage. Thayer admits that these often appear conspicuous, but argues that against varied backgrounds, white offers "the "greatest average inconspicuousness" against the ocean" (his italics) or against the bright sky when seen from below. Chapter 13 analyses "markings and patterns in detail, starting with a color plate that shows the effect of disruptive patterning, which Thayer calls "strong 'secant' and 'ruptive' patterns". Using a photograph of an oystercatcher at its nest by Cherry and Richard Kearton, Thayer argues that the boldly marked bird (mainly black above, white below, with red beak) is both countershaded and "ruptively" patterned. Chapter 14 discusses the barred markings of hawks and owls, with further fine plates of photographs by the Keartons of disruptively patterned waders and their cryptic chicks
|
https://en.wikipedia.org/wiki?curid=37724748
|
Concealing-Coloration in the Animal Kingdom The ringed plover is described as having "eye-masking and 'obliterative' shadow-and-hole-picturing pattern". Chapter 15 describes the leg feather patterns of hawks, asserting that these "pantaloons" mask these "dangerous talons" to facilitate attack, just as their beaks, like the beaks of wading birds, are masked paradoxically with "gaudy colors". Chapter 16 controversially claims that the iridescent colours of, for example, the speculum wing patch of the mallard and other ducks is "obliterative", the "brightly changeable plumage" serving to camouflage the wearer in varying conditions. Thayer asserts that such brightly colored species as the European kingfisher and the purple gallinule are camouflaged: Chapter 17 argues that bird plumage has "many devices" to conceal the animals' outlines. Even the "enormously developed feather-appendages" of the birds of paradise are argued to provide camouflage in this way. Sexual display is mentioned but dismissed as not being the sole reason for the colours, outlines and patterns of the male birds. Chapter 18 briefly discusses mimicry, before returning to "the evident paramount importance of the "obliterative" function", this time of the "brilliant, flowerlike" heads of hummingbirds. The one case that Thayer admits is mimetic is the goatsucker of Trinidad, a plant mimic that perches "by day and night" on a tree stump or branch, where the purpose of the mimicry is crypsis
|
https://en.wikipedia.org/wiki?curid=37724748
|
Concealing-Coloration in the Animal Kingdom Chapter 19 concludes the description of bird plumage, claiming that birds from the tropical forests to the "snowy north", including woodpeckers and the blue jay are all "colored for inconspicuousness". Chapters 20, 21, and 22 discuss the "disguising-coloration" of mammals, including the whales which "are equipped with a full obliterative shading of surface-colors". The bats are admitted to have very little in the way of countershading, unlike all other families in the order. Thayer notes that a few species with strong defences such as hedgehogs, porcupines, echidnas, pangolins and "some armadillos" are exceptions, along with some beasts which "enjoy a like security by virtue of their gigantic bigness", including the elephants, rhinoceroses, and hippopotamuses. The domestic hare is shown to be strongly countershaded with a pair of photographs "from life", one sitting and one "laid on its back, outdoors, so that the obliterative shading is reversed". Chapter 21 asserts that zebras "must be extraordinarily inconspicuous" against vegetation, a claim derided by Theodore Roosevelt (see below). Chapter 22 addresses the problem of the "few [beasts] whose bold, clear patterns seem to defy that foremost obliterative law." These include the skunks, the African zoril (striped polecat) and the teledu (stink badger) of Java, which all have dark underparts and white upperparts
|
https://en.wikipedia.org/wiki?curid=37724748
|
Concealing-Coloration in the Animal Kingdom Thayer dismisses the aposematism of these species, instead asserting the effectiveness of their camouflage: Several photographs using stuffed skins of skunks attempt to prove the point. The chapter goes on to claim that roseate spoonbills, flamingoes, and prongbuck are all obliteratively colored. The raccoon's head resembles "the end of a hollow stump or log", while its tail is said to be "distractive", the strong banding serving like an eyespot to divert the attention of a predator to the tail rather than the head while the animal dives down a hole. But Thayer is unable to resist arguing that when "quiet, their tail-bands act "obliteratively"". Chapter 23 looks at fish, admitting frankly that the authors "know next to nothing about fishes from the standpoint of systematic science", but saying that they have gathered a "trustworthy general estimate" of their "disguising coloration" from market stalls, museums and books. Many fish are countershaded. The bioluminescence of some deep sea fish and other animals is seen as a problem as it is not "obliterative"; the possibility of counterillumination camouflage is not considered. Chapter 24 considers the reptiles and amphibians. These are noted to be predominantly green, often with "ruptive" patterns. Plate 11 treats a "Copperhead snake on dead leaves", the caption explaining that "This is a bona-fide study of a Copperhead Snake among dead leaves—its normal situation." There is a full-page sheet of card, cut out in the shape of the snake lying on a bed of leaves
|
https://en.wikipedia.org/wiki?curid=37724748
|
Concealing-Coloration in the Animal Kingdom When this is folded back, a painting by Rockwell Kent and Abbott Thayer "(Also G.H. Thayer and E.B. Thayer)" is revealed, showing the snake's outline powerfully disrupted by its zigzag pattern among the light and shade of the leaf litter. Chapter 24 mentions that some terrestrial salamanders "are rather brightly pied with black and whitish, or yellow", while other amphibians "are extremely gaudy—wearing much bright blue, green, purple and sometimes red." It suggests that some of these markings are "baits or targets", again to distract predators from striking at the head, while the salamander markings are left as a problem as the authors "know too little about the habits" of these species. It is admitted that "the disguising coloration of many of them is very obscure." The final chapters 25, 26 and 27 turn to the insects. Chapter 25 looks at caterpillars, with, as Poulton had earlier noted, convincing examples of countershading. Plate 13 shows caterpillars including the "larger-spotted beech-leaf-edge caterpillar" both in position "passing for a part of the leaf on which it is feeding", strongly cryptic and flattened like a slightly browning leaf, and inverted, when its countershading makes it appear conspicuously solid. Chapter 26 looks at other insects and spiders, noting the "famous leaf-mimicking "Kallima inachus"" butterfly of India, but again claiming that even conspicuous butterflies are in fact "obliterative"
|
https://en.wikipedia.org/wiki?curid=37724748
|
Concealing-Coloration in the Animal Kingdom Eye-spots are mentioned, but instead of noting that these might be distractive, they are asserted to be "dazzling", appearing as holes, and thus functioning as disruptive camouflage. The text ends with a paragraph that asks if it is "any wonder that artists should feel keen delight in looking at the disguising-patterns worn by animals?" These are "triumphs of art", where the student can find "in epitome, painted and perfected by Nature herself", the typical color and pattern scheme of each kind of landscape. An appendix provides extracts from a "very remarkable addition to our subject", Poulton's 1907 observations of color change in chameleons. The Thayers' views were vigorously criticised in 1911 by Theodore Roosevelt, an experienced big game hunter and naturalist familiar with animal camouflage as well as a politician, in a lengthy article in the "Bulletin of the American Museum of Natural History". Roosevelt begins by writing that the Thayers expounded the "doctrine" of concealing coloration "in its extreme form", which he thought had been "pushed to such a fantastic extreme and to include such wild absurdities as to call for the application of common sense thereto." Then, "to show the sweeping claims made", Roosevelt quotes verbatim eight passages from the book, one after the other, 500 words in all, the last one being "'All patterns and colors whatsoever of all animals that ever prey or are preyed upon are under certain normal circumstances obliterative
|
https://en.wikipedia.org/wiki?curid=37724748
|
Concealing-Coloration in the Animal Kingdom '" He then observes that the Thayers' claims, both in "pictures" and in writing, are not so much arguments as plain "misstatements of facts, or wild guesses put forward as facts." He puts these down to enthusiasm rather than dishonesty, and as an example critiques the picture (the book's frontispiece) of the peacock in a tree This, Roosevelt writes, would be an extremely rare sight in nature. Worse, the female (the peahen) would, he argues, be conspicuous in those conditions. The Thayers have chosen a blue sky to argue that the peacock is camouflaged; but then they choose a "white" sky to allow the prongbuck's white rump to fade into that background. This, Roosevelt argues, is so dishonest that an engineer who constructed a report in that way would at once be dismissed, and the directors of a corporation who "tried to float shares on the strength of such a report" would be liable to "prosecution for fraud". Roosevelt had recently returned from his African safari, having seen, admired and shot large numbers of animals. He was scornful of Thayer's theories, which he described as "phantasmagoria", and the writer as "a well meaning and ill-balanced enthusiast". Thayer's suggestion that the white markings on the body of the harnessed bush buck are meant to resemble "flecks of water shine" is dismissed as wild, with the observation from personal experience that bush buck spend little time in watery places, while the "situtunga or lechwe, which lack the spots" spend more
|
https://en.wikipedia.org/wiki?curid=37724748
|
Concealing-Coloration in the Animal Kingdom Roosevelt does not refrain from harshness: he describes the camouflaged flamingo theory as "probably the wildest" of "all the wild absurdities to which Mr. Thayer has committed himself". Thayer was also roundly criticised in 1911 by herpetologist Thomas Barbour and conservation pioneer John C. Phillips in "The Auk", where they wrote that Barbour and Phillips warmly welcome Thayer's work on countershading "which he has so excellently demonstrated"; they "protest gently" against his "slightly patronizing" treatment of the camouflage of birds like woodcock and grouse "which has been known and recognized since ornithology began"; and go on to the attack on his claims for the flamingo: They are equally critical of his roseate spoonbill, observing that the painting looks nothing like "actual skins of the species". As for the wood duck, they point out its [sexual] "dimorphism of plumage", and that the male spends the summer in eclipse plumage, while he is Barbour and Phillips note that Thayer "in his enthusiasm, has ignored or glossed over [sexual dimorphism] with an artistic haze." They also question whether every animal needs protection. "By skilful jugglings we are shown how anything and everything may be rendered inconspicuous," citing the skunk among other boldly black and white animals with both the skunk coloration and the "well-known skunk smell". They conclude by writing that they have "purposely omitted calling special attention to the strong features of the book" and that they have no axe to grind
|
https://en.wikipedia.org/wiki?curid=37724748
|
Concealing-Coloration in the Animal Kingdom The English ornithologists Douglas Dewar and Frank Finn write in their 1909 book "The Making of Species" that Thayer "seems to be of opinion that "all" animals are cryptically or, as he calls it, concealingly or obliteratively coloured". They note that Edward Bagnall Poulton had written approvingly of Thayer, and that Thayer had asserted that almost all animals were countershaded. They agree that countershading exists, but to his suggestion that it is universal "we feel sorely tempted to poke fun at him", and promptly ask any reader who agrees with Thayer that every animal is countershaded to look at a flock of rooks at sunset. They admit that camouflage is in general advantageous, but point out that the different plumages of seasonally and sexually dimorphic birds cannot all be explained as camouflage, considering the conspicuous colours of the male birds: They counter the further argument that hens may be in more danger than cocks, through sitting on nests, by observing that in many dimorphic species, the showy cock shares the work of incubating the eggs. The zoologist and camouflage expert Hugh Cott, in his 1940 book "Adaptive Coloration in Animals", writes that Cott attacks Thayer's comprehensive assertion that "all patterns and colors whatsoever..
|
https://en.wikipedia.org/wiki?curid=37724748
|
Concealing-Coloration in the Animal Kingdom are obliterative", and continues more specifically with a detailed rebuttal of both the text and Thayer's contrived paintings: Cott then gives the examples of the peacock in the woods with the blue sky behind the neck; the "flock of red Flamingoes matching a red sunset sky", and the roseate spoonbill "whose pink plumage matches a pink cloud scheme". He then lists the cases of the white flamingo, the skunk and the white rump of the prongbuck, quoting Roosevelt ("The raven's coloration is of course concealing if it is put into a coal scuttle"), notes "How unreasonable are extreme views like that adopted by Thayer", and admits that criticisms of "certain of Thayer's conclusions" are justified, before returning to the attack on those critics, robustly defending the "theory of protective and aggressive resemblance". More favourably, Cott explicitly recognises Thayer's work on countershading, though granting Edward Bagnall Poulton's partial anticipation with his work on the chrysalis of the purple emperor butterfly. Further, Cott quotes Thayer's description of countershading, and Cott's Figure 1, of countershaded fish, is captioned "Diagrams illustrating Thayer's principle of obliterative shading". Implicitly, also, Cott follows Thayer in his Figure 3 "Larva of Eyed Hawk-moth" in both "natural (e.g
|
https://en.wikipedia.org/wiki?curid=37724748
|
Concealing-Coloration in the Animal Kingdom 'up-side-down')" and "unnatural" positions; in his Figure 5 drawing of the disruptive effect of the stripes and bold markings of woodcock chicks (like Thayer's Figure 81); in his Plate 7, with (just like Thayer's Figure 7) a photograph of a white cock against a white background; in his Figure 18 and front cover drawings of a copperhead snake lying on a bed of leaves, with and without its disruptive pattern (like Thayer's Plate 11) and so on. The evolutionary biologist John Endler, reviewing the topic of camouflage in "Proceedings of the Royal Society B" in 2006, cites Thayer's 1909 book three times: for disruption, with "conspicuous elements [which] distract the predator's attention and break up the body outline, making detection of the prey difficult"; for "masquerade, [where] the prey is detected as distinct from the visual background but not recognized as edible.., for example by resembling a leaf"; and for countershading, where "False gradients are common in animal colour patterns, leading to misleading appearance of shape, even when they do not disrupt the body outline". Thayer is by far the earliest source used by Endler; the only other early source he cites (for disruption) is Hugh Cott's 1940 "Adaptive Coloration in Animals"
|
https://en.wikipedia.org/wiki?curid=37724748
|
Concealing-Coloration in the Animal Kingdom The art and science writer Peter Forbes notes that Thayer became obsessed by the "flattening effect" of countershading, and that far from being a scientist, he was "an artist whose idealist fervour, edged by deep insecurity, led him to regard his findings less as discovery than as revelation." Describing "Concealing-Coloration" as a "magnum opus", Forbes writes that by 1909 "Thayer's prophetic intolerance was in full flood", that he was overcompensating for his need for approval of his artwork, and that he failed to see that acceptance of ideas in science does not depend on "the vehemence with which they are expressed". In Forbes's view, Thayer was battling for the rights of artists over scientists, citing Thayer ("it properly belongs to the realm of pictorial art") in evidence. Apart from Thayer's "bizarre" flamingos, Forbes calls Thayer's opposition to Batesian mimicry "extreme". For Forbes, "Reading Thayer's book today is a strange experience. He sets out with the idea that "every single creature" is perfectly camouflaged", and then "tries to bludgeon his readers" into agreeing. Forbes is critical of Thayer's rejection of warning coloration, quoting Thayer's daughter Gladys as writing "My father's special mission was "tasting" butterflies"; Thayer apparently wanted to prove that mimicry was the wrong explanation as both model and mimic tasted the same. Forbes observes that natural selection did not have to contend with human reactions to the taste of butterflies
|
https://en.wikipedia.org/wiki?curid=37724748
|
Concealing-Coloration in the Animal Kingdom The philosopher and jazz musician David Rothenberg, in his 2012 book "Survival of the Beautiful" on the relationship between aesthetics and evolution, argues that while the Thayers' book set out the principles of camouflage: "From observation of nature ... art contributed to the military needs of society", Thayer, following Charles Darwin, was "swept up in the idea that every animal had evolved to perfectly live in its surroundings", but was emotionally unable to accept the other "half" of Darwin's view of animal coloration: Rothenberg then discusses the Thayers' account of the wood duck, which Rothenberg calls "our most garishly colored duck". He explains that the Thayers believed they, "trained as artists", had seen what earlier observers had missed: The Smithsonian American Art Museum's website, describing the Thayers' book as "controversial", writes sceptically that
|
https://en.wikipedia.org/wiki?curid=37724748
|
Double layer forces An electrical double layer develops near charged surfaces (or another charged objects) in aqueous solutions. Within this double layer, the first layer corresponds to the charged surface. These charges may originate from tightly adsorbed ions, dissociated surface groups, or substituted ions within the crystal lattice. The second layer corresponds to the diffuse layer, which contains the neutralizing charge consisting of accumulated counterions and depleted coions. The resulting potential profile between these two objects leads to differences in the ionic concentrations within the gap between these objects with respect to the bulk solution. These differences generate an osmotic pressure, which generates a force between these objects. These forces are easily experienced when hands are washed with soap. Adsorbing soap molecules make the skin negatively charged, and the slippery feeling is caused by the strongly repulsive double layer forces. These forces are further relevant in many colloidal or biological systems, and may be responsible for their stability, formation of colloidal crystals, or their rheological properties. The most popular model to describe the electrical double layer is the Poisson-Boltzmann (PB) model. This model can be equally used to evaluate double layer forces. Let us discuss this model in the case of planar geometry as shown in the figure on the right. In this case, the electrical potential profile "ψ"("z") near a charged interface will only depend on the position "z"
|
https://en.wikipedia.org/wiki?curid=37732235
|
Double layer forces The corresponding Poisson's equation reads in SI units where "ρ" is the charge density per unit volume, "ε" the dielectric permittivity of the vacuum, and "ε" the dielectric constant of the liquid. For a symmetric electrolyte consisting of cations and anions having a charge ±"q", the charge density can be expressed as where "c" = "N"/"V" are the concentrations of the cations and anions, where "N" are their numbers and "V" the sample volume. These profiles can be related to the electrical potential by considering the fact that the chemical potential of the ions is constant. For both ions, this relation can be written as where formula_4 is the reference chemical potential, "T" the absolute temperature, and "k" the Boltzmann constant. The reference chemical potential can be eliminated by applying the same equation far away from the surface where the potential is assumed to vanish and concentrations attain the bulk concentration "c". The concentration profiles thus become where "β" = 1/("kT"). This relation reflects the Boltzmann distribution of the ions with the energy ±"qψ". Inserting these relations into the Poisson equation one obtains the PB equation The potential profile between two plates is normally obtained by solving this equation numerically. Once the potential profile is known, the force per unit area between the plates expressed as the disjoining pressure Π can be obtained as follows
|
https://en.wikipedia.org/wiki?curid=37732235
|
Double layer forces The starting point is the Gibbs–Duhem relation for a two component system at constant temperature Introducing the concentrations "c" and using the expressions of the chemical potentials "μ" given above one finds The concentration difference can be eliminated with the Poisson equation and the resulting equation can be integrated from infinite separation of the plates to the actual separation "h" by realizing that Expressing the concentration profiles in terms of the potential profiles one obtains From a known electrical potential profile "ψ"("z") one can calculate the disjoining pressure from this equation at any suitable position "z". Alternative derivation of the same relation for disjoining pressure involves the stress tensor. When the electric potentials or charge densities are not too high, the PB equation can be simplified to the Debye-Hückel (DH) equation. By expanding the exponential function in the PB equation into a Taylor series, one obtains The parameter "κ" is referred to as the Debye length, and some representative values for a monovalent salt in water at 25°C with "ε" ≃ 80 are given in the table on the right. In non-aqueous solutions, Debye length can be substantially larger than the ones given in the table due to smaller dielectric constants. The DH model represents a good approximation, when the surface potentials are sufficiently low with respect to the limiting values The numerical value refers to a monovalent salt and 25°C
|
https://en.wikipedia.org/wiki?curid=37732235
|
Double layer forces In practice, the DH approximation remains rather accurate up to surface potentials that are comparable to the limiting values given above. The disjoining pressure can be obtained from the PB equation given above, which can also be simplified to the DH case by expanding into Taylor series. The resulting expression is The substantial advantage of the DH model over the PB model is that the forces can be obtained analytically. Some of the relevant cases will be discussed below. When the surfaces are sufficiently far apart, the potential profiles originating from each individual surface will not be much perturbed by the presence of the other surface. This approximation thus suggests that one can simply add (superpose) the potentials profiles originating from each surface as illustrated the figure. Since the potential profile passes through a minimum at the mid-plane, it is easiest to evaluate the disjoining pressure at the midplane. The solution of the DH equation for an isolated wall reads where "z" is the distance from the surface and "ψ" the surface potential. The potential at the midplane is thus given by twice the value of this potential at a distance "z" = "h"/2. The disjoining pressure becomes The electrostatic double layer force decays in an exponential fashion. Due to the screening by the electrolyte, the range of the force is given by the Debye length and its strength by the surface potential (or surface charge density)
|
https://en.wikipedia.org/wiki?curid=37732235
|
Double layer forces This approximation turns out to be exact provided the plate-plate separation is large compared to the Debye length and the surface potentials are low. This result can be simply generalized to highly charged surfaces, but only at larger separations. Even if the potential is large close to the surface, it will be small at larger distances, and can be described by the DH equation. However, in this case one has to replace the actual diffuse layer potential "ψ" with the effective potential "ψ". Within the PB model, this effective potential can be evaluated analytically, and reads The superposition approximation can be easily extended to asymmetric systems. Analogous arguments lead to the expression for the disjoining pressure where the super-scripted quantities refer to properties of the respective surface. At larger distances, oppositely charged surfaces repel and equally charged ones attract. While the superposition approximation is actually exact at larger distances, it is no longer accurate at smaller separations. Solutions of the DH or PB equations in between the plates provide a more accurate picture at these conditions. Let us only discuss the symmetric situation within the DH model here. This discussion will introduce the notion of "charge regulation", which suggests that the surface charge (and the surface potential) may vary (or regulate) upon approach. The DH equation can be solved exactly for two plates
|
https://en.wikipedia.org/wiki?curid=37732235
|
Double layer forces The boundary conditions play an important role, and the surface potential and surface charge density formula_19 and formula_20 become functions of the surface separation "h" and they may differ from the corresponding quantities "ψ" and "σ" for the isolated surface. When the surface charge remains constant upon approach, one refers to the "constant charge" (CC) boundary conditions. In this case, the diffuse layer potential will increase upon approach. On the other hand, when the surface potential is kept constant, one refers to "constant potential" (CP) boundary condition. In this case, the surface charge density decreases upon approach. Such decrease of charge can be caused by adsorption of desorption of charged ions from the surface. Such variation of adsorbed species upon approach has also been referred to as "proximal adsorption". The ability of the surface to regulate its charge can be quantified by the regulation parameter where "C" = "ε" "ε κ" is the diffuse layer capacitance and "C" the inner (or regulation) capacitance. The CC conditions are found when "p" = 1 while the CP conditions for "p" = 0. The realistic case will be typically situated in between
|
https://en.wikipedia.org/wiki?curid=37732235
|
Double layer forces By solving the DH equation one can show that diffuse layer potential varies upon approach as while the surface charged density obey a similar relation The swelling pressure can be found by inserting the exact solution of the DH equation into the expressions above and one finds Repulsion is strongest for the CC conditions ("p" = 1) while it is weaker for the CP conditions ("p" = 0). The result of the superposition approximation is always recovered at larger distances but also for "p" = 1/2 at all distances. The latter fact explains why the superposition approximation can be very accurate even at small separations. Surfaces regulate their charge and not infrequently the actual regulation parameter is not far away from 1/2. The situation is exemplified in the figure below. From stability considerations one can show that "p" < 1 and that this parameter may also becomes negative. These results can be extended to asymmetric case in a straightforward way. When surface potentials are replaced by effective potentials, this simple DH picture is applicable for more highly charged surfaces at sufficiently larger distances. At shorter distances, however, one may enter the PB regime and the regulation parameter may not remain constant. In this case, one must solve the PB equation together with an appropriate model of the surface charging process. It was demonstrated experimentally that charge regulation effects can become very important in asymmetric systems
|
https://en.wikipedia.org/wiki?curid=37732235
|
Double layer forces Interactions between various objects were studied within the DH and PB models by many researchers. Some of the relevant results are summarized in the following. Non-planar geometries: Objects of other than planar geometries can be treated within the Derjaguin approximation, provided their size is substantially larger than the Debye length. This approximation has been used to estimate the force between two charged colloidal particles as shown in the first figure of this article. The exponential nature of these repulsive forces and the fact that its range is given by the Debye length was confirmed experimentally by direct force measurements, including surface forces apparatus, colloidal probe technique, or optical tweezers. The interaction free energy involving two spherical particles within the DH approximation follows the Yukawa or screened Coulomb potential where "r" is the center-to-center distance, "Q" is the particle charge, and "a" the particle radius. This expression is based on the superposition approximation and is only valid at large separations. This equation can be extended to more highly charged particles by reinterpreting the charge "Q" as an effective charge. To address the interactions in other situation, one must resort to numerical solutions of the DH or PB equation. Non-uniform or patchy charge distribution: Interaction between surfaces with non-uniform and periodic charge distribution has been analyzed within the DH approximation
|
https://en.wikipedia.org/wiki?curid=37732235
|
Double layer forces Such surfaces are referred to have a mosaic or patch-charge distribution. One important conclusion from these studies is that there is an additional attractive electrostatic contribution, which also decays exponentially. When the non-uniformities are arranged in a quadratic lattice with spacing "b", the decay length "q" of this additional attraction can be expressed as At high salt levels, this attraction is screened as the interaction between uniformly charged surfaces. At lower salt levels, however, the range of this attraction is related to the characteristic size of the surface charge heterogeneities. Three-body forces: The interactions between weakly charged objects are pair-wise additive due to the linear nature of the DH approximation. On the PB level, however, attractive three-body forces are present. The interaction free energy between three objects 1, 2, and 3 can be expressed as where "F" are the pair free energies and "ΔF" is the non-additive three-body contribution. These three-body contributions were found to be attractive on the PB level, meaning that three charged objects repel less strongly than what one would expect on the basis of pair-wise interactions alone. More accurate description of double layer interactions can be put forward on the "primitive model". This model treats the electrostatic and hard-core interactions between all individual ions explicitly. However, it includes the solvent only in a "primitive" way, namely as a dielectric continuum
|
https://en.wikipedia.org/wiki?curid=37732235
|
Double layer forces This model was studied in much detail in the theoretical community. Explicit expressions for the forces are mostly not available, but they are accessible with computer simulations, integral equations, or density functional theories. The important finding from these studies is that the PB description represents only a mean-field approximation. This approximation is excellent in the so-called "weak coupling regime", that is for monovalent electrolytes and weakly charged surfaces. However, this description breaks down in the "strong coupling regime", which may be encountered for multivalent electrolytes, highly charged systems, or non-aqueous solvents. In the strong coupling regime, the ions are strongly correlated, meaning that each ion has an exclusion hole around itself. These correlations lead to strong ion adsorption to charged surfaces, which may lead to charge reversal and crystallization of these ions on the surface. These correlations may also induce attractive forces. The range of these forces is typically below 1 nm. Around 1990, theoretical and experimental evidence has emerged that forces between charged particles suspended in dilute solutions of monovalent electrolytes might be attractive at larger distances. This evidence is in contradiction with the PB theory discussed above, which always predicts repulsive interactions in these situations. The theoretical treatment leading to these conclusions was strongly criticized
|
https://en.wikipedia.org/wiki?curid=37732235
|
Double layer forces The experimental findings were mostly based on video-microscopy, but the underlying data analysis was questioned concerning the role of impurities, appropriateness of image processing techniques, and the role of hydrodynamic interactions. The majority of the scientific community remains skeptical concerning such like-charge attractions and advocates the classical PB approach discussed above. Double layer interactions are relevant in a wide number of phenomena. These forces are responsible for swelling of clays. They may also be responsible for the stabilization of colloidal suspension and will prevent particle aggregation of highly charged colloidal particles in aqueous suspensions. At low salt concentrations, the repulsive double layer forces can become rather long-ranged, and may lead to structuring of colloidal suspensions and eventually to formation of colloidal crystals. Such repulsive forces may further induce blocking of surfaces during particle deposition. Double layer interactions are equally relevant for surfactant aggregates, and may be responsible to the stabilization of cubic phases made of spheroidal micelles or lamellar phases consisting of surfactant or lipid bilayers.
|
https://en.wikipedia.org/wiki?curid=37732235
|
Nuclear energy in Saudi Arabia Saudi Arabia has plans to create a domestic nuclear industry in anticipation of high growth in domestic energy consumption. One set of plans proposes building two nuclear reactors by 2020, and have sixteen built by 2030. The government's intent is to use the electrical power thus produced in place of power obtained from petroleum-fired powerplants, thus freeing that petroleum for export. Currently, Saudi Arabia produces 52 GW from 79 non-nuclear powerplants. The government intends to produce 110 GWe by 2032. This would require 16 reactors by 2019 at a cost of $7B each. Saudi Arabia hopes to produce surplus capacity for export, although that would depend on the rate of domestic electrical energy demand. One prediction foresees domestic consumption at 75 GWe by 2018, rising to 120 GWe by 2030. The Saudi program is reckoned to be the second most developed in the Arab world, behind their Persian Gulf neighbour United Arab Emirates. In 2010, the King Abdallah Center for Atomic and Renewable Energy (KAcare) was founded to oversee Saudi Arabia's nuclear program under its president, Hashim Abdullah Yamani (former minister of energy and of commerce). KAcare will represent Saudi Arabia at the IAEA and be responsible for Saudi nuclear energy power, supervision of nuclear power production and management of nuclear waste. Saudi Arabia has no fuel production facilities and would be reliant on nuclear fuel from the global market
|
https://en.wikipedia.org/wiki?curid=37735424
|
Nuclear energy in Saudi Arabia In 2010, a deal was signed with Toshiba and Shaw to build reactors in Saudi Arabia, and with Exelon to manage the nuclear facilities. The group will either be using the Advanced Boiling Water Reactor or Westinghouse's AP1000. In February 2011, Saudi Arabia signed its first nuclear accord with France, a leader in nuclear technology exports. It is expected that Saudi Arabia will build a number of nuclear reactors in the near future with the aid of France to expand King Abdullah's Atomic and Renewable Energy City devoted to research and the peaceful application of nuclear energy. In March 2015, a memorandum of understanding was signed between Saudi Arabia and South Korea. This could lead to the construction of at least two South Korean-designed SMART reactors in Saudi Arabia. SMART stands for System-integrated Modular Advanced ReacTor. In April 2019, the IAEA confirmed that Saudi Arabia was likely to have a functioning nuclear reactor within a year, but had not agreed to IAEA inspections.
|
https://en.wikipedia.org/wiki?curid=37735424
|
Harold Friedman Harold Leo Friedman (born 24 March 1923 in Manhattan, New York City; died 16 September 2005 in Stony Brook, Long Island, New York) was an American physical chemist who contributed to the study of thermodynamic properties of fluids with applications in oceanography and physiology.
|
https://en.wikipedia.org/wiki?curid=37774062
|
Prokofiev (crater) Prokofiev is a crater on the north pole of the planet Mercury, named after the Russian composer Sergei Prokofiev. Data from the "MESSENGER" spacecraft indicates that it contains water ice and organic compounds. Although other craters in Mercury's north polar region are also believed to contain ice, Prokofiev is the largest of them, with surface ice at the bottom in eternal darkness.
|
https://en.wikipedia.org/wiki?curid=37785586
|
RV Neil Armstrong (AGOR-27) RV "Neil Armstrong" (AGOR-27) is the designation for a new oceanographic research ship, first of the s, to be owned by the United States Navy and operated by Woods Hole Oceanographic Institution. Secretary of the Navy Ray Mabus announced on September 24, 2012 that the research vessel was to be named after Neil Armstrong, the first person to walk on the Moon and a former naval aviator who served in the Korean War. The ship was ordered in May 2010 as a replacement for , operated by Woods Hole Oceanographic Institution since 1970. The ship was constructed by Dakota Creek Industries of Anacortes, Washington and scheduled for completion in 2014 for entry into service in 2015. It was launched on 29 March 2014, christened by Carol Armstrong, passed sea trials 7 August 2015 and delivered to the Navy on 23 September 2015. A sister ship, , was launched 9 August 2014 to be operated by Scripps Institution of Oceanography under a renewable charter-party agreement. "Neil Armstrong" is a commercially designed mono hull research vessel, capable of coastal and deep ocean operations, and equipped with cranes and winches for over-the-side loading of research equipment and supplies, as well as accommodations for twenty-four scientists. The ship is powered by a multi-drive low-voltage diesel electric propulsion system for efficiency and lower maintenance and fuel costs
|
https://en.wikipedia.org/wiki?curid=37789560
|
RV Neil Armstrong (AGOR-27) Both "Neil Armstrong"-class ships have state of the art oceanographic equipment allowing deep ocean mapping and information technology for ship monitoring and worldwide land-based communication. "Neil Armstrong" has more than 130 square meters of adjustable lab space, supplied by a flash evaporation desalination system.
|
https://en.wikipedia.org/wiki?curid=37789560
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.