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73,421,121 | https://en.wikipedia.org/wiki/Pertusaria%20elixii | Pertusaria elixii is a rare species of corticolous (bark-dwelling), crustose lichen in the family Pertusariaceae. Found in Thailand, it was formally described as a new species in 2005 by Sureeporn Jariangprasert. The type specimen was collected by the author from Doi Inthanon National Park (Chom Thong district, Chiang Mai) at an altitude of , where it was found growing on Betula alnoides. The species epithet honours Australian lichenologist John Elix, who assisted the author in chemical analysis of lichen specimens. Pertusaria elixii is distinguished from related species by the number of in its ascus (four), and the presence of 2'-O-methyl-substituted homologues of perlatolic acid.
See also
List of Pertusaria species
References
elixii
Lichen species
Lichens described in 2005
Lichens of Indo-China
Species known from a single specimen | Pertusaria elixii | [
"Biology"
] | 202 | [
"Individual organisms",
"Species known from a single specimen"
] |
73,421,199 | https://en.wikipedia.org/wiki/Pertusaria%20kansriae | Pertusaria kansriae is a rare species of corticolous (bark-dwelling), crustose lichen in the family Pertusariaceae. Found in Thailand, it was formally described as a new species in 2005 by Sureeporn Jariangprasert. The type specimen was collected by the author from the Doi Inthanon National Park (Chom Thong district, Chiang Mai) at an altitude of , where it was found growing on a tree trunk in a mixed forest; the species is known only from this specimen. The species epithet kansriae honours Thai lichenologist Kansri Boonpragob, who inspired the author to study lichens. Distinguishing characteristics of the lichen are the number of in the ascus (four), and the presence of the lichen products 4,5-dichlorolichexanthone and 2'-O-methylstenosporic acid.
See also
List of Pertusaria species
References
kansriae
Lichen species
Lichens described in 2005
Lichens of Indo-China
Species known from a single specimen | Pertusaria kansriae | [
"Biology"
] | 226 | [
"Individual organisms",
"Species known from a single specimen"
] |
73,421,209 | https://en.wikipedia.org/wiki/Pertusaria%20krabiensis | Pertusaria krabiensis is a rare species of corticolous (bark-dwelling), crustose lichen in the family Pertusariaceae. Found in peninsular Thailand, it was formally described as a new species in 2005 by Sureeporn Jariangprasert. The type specimen was collected from near the Wat Thamp Suea Temple in Krabi; the species is known only from the type. The species epithet combines the name of the type locality with the Latin suffix -ensis ("place of origin"). The main distinguishing characteristics of Pertusaria krabiensis are its ascospores (which number 8 per ascus), and the presence of homologues of the lichen product 2-O-methylperlatolic acid.
See also
List of Pertusaria species
References
krabiensis
Lichen species
Lichens described in 2005
Lichens of Indo-China
Species known from a single specimen | Pertusaria krabiensis | [
"Biology"
] | 198 | [
"Individual organisms",
"Species known from a single specimen"
] |
73,421,221 | https://en.wikipedia.org/wiki/2%2C3-Dimethyl-1-butene | 2,3-Dimethyl-1-butene is an organic compound with the formula . Like the other isomers of dimethylbutene, it is a colorless liquid. Together with 2,3-dimethyl-2-butene it can be produced by dimerization of propylene. It is a precursor to the commercial fragrance tonalide.
References
Alkenes | 2,3-Dimethyl-1-butene | [
"Chemistry"
] | 83 | [
"Organic compounds",
"Alkenes"
] |
73,421,540 | https://en.wikipedia.org/wiki/Allographa%20pedunculata | Allographa pedunculata is a species of script lichen in the family Graphidaceae, discovered in the Galápagos Islands. The species is characterized by its distinctly stalked and contains norstictic acid. It is similar to other species in the Graphis nuda species complex but has the longest in the group.
Taxonomy
The lichen was first formally described by lichenologists Frank Bungartz and André Aptroot in 2010, as a member of the genus Graphis. The species is part of the Graphis nuda group and is closely related to Graphis emersa, another species containing norstictic acid. Robert Lücking and Klaus Kalb transferred the taxon to the genus Allographa in 2018.
Description
The thallus of Allographa pedunculata is thin and continuous, either forming a thin film encrusting bryophytes and plant debris, or granular to granular , over rock. The thallus surface is smooth and shiny, pale creamy white to brownish, and not . Its apothecia are typically distinctly and conspicuously stalked, rarely , and . The lirellae are very broad and short, and never branched. The are thick, entire, and black, only basally more or less covered by a thin thallus layer. The hymenium is hyaline and clear. The are hyaline to pale gray, brownish with age, and measure 22–27 by (80)130–210 μm; they are transversely septate with (11)16–22 cells.
The lichen contains norstictic acid, which causes a K+ (yellow turning red) (red crystals) and P+ (yellow) spot test reactions. It is C−.
Habitat and distribution
Allographa pedunculata is currently known from a single collection site on a sheltered and shaded basalt cliff at the top of Cerro Gavilán in Santiago Island. The species prefers rock substrates and is found in a distinct habitat compared to its close relative, Graphis cleistomma, which has been found encrusting bryophytes and plant debris.
References
pedunculata
Lichen species
Lichens described in 2010
Lichens of the Galápagos Islands
Taxa named by André Aptroot
Species known from a single specimen
Taxa named by Frank Bungartz | Allographa pedunculata | [
"Biology"
] | 483 | [
"Individual organisms",
"Species known from a single specimen"
] |
73,422,141 | https://en.wikipedia.org/wiki/C7H16O2 | {{DISPLAYTITLE:C7H16O2}}
The molecular formula C7H16O2 (molar mass: 132.203 g/mol) may refer to:
Prenderol
2-Methyl-2-propyl-1,3-propanediol | C7H16O2 | [
"Chemistry"
] | 62 | [
"Isomerism",
"Set index articles on molecular formulas"
] |
73,422,229 | https://en.wikipedia.org/wiki/HD%20185075 | HD 185075, also known as HR 7459 or rarely 65 G. Telescopii, is a solitary star located in the southern constellation Telescopium. It has an apparent magnitude of 6.26, placing it near the limit for naked eye visibility, even under ideal conditions. Gaia DR3 parallax measurements imply a distance of 422 light years and it is currently receding with a heliocentric radial velocity of . At its current distance, HD 185075's brightness is diminished by 0.23 magnitudes due to interstellar dust and it has an absolute magnitude of +0.92.
This is an evolved red giant with a stellar classification of K0 III. It has 1.34 times the mass of the Sun but it has expanded to 12.6 times the Sun's radius. It radiates 79.8 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of , giving it an orange hue. HD 185075 is particularly metal deficient with an iron abundance 38% that of the Sun's ([Fe/H] = −0.42) and it spins too slowly for its projected rotational velocity to be measured accurately.
References
Telescopium
K-type giants
7459
185075
096781
Telescopium, 66
Durchmusterung objects | HD 185075 | [
"Astronomy"
] | 282 | [
"Telescopium",
"Constellations"
] |
73,422,453 | https://en.wikipedia.org/wiki/Topological%20Yang%E2%80%93Mills%20theory | In gauge theory, topological Yang–Mills theory, also known as the theta term or -term is a gauge-invariant term which can be added to the action for four-dimensional field theories, first introduced by Edward Witten. It does not change the classical equations of motion, and its effects are only seen at the quantum level, having important consequences for CPT symmetry.
Action
Spacetime and field content
The most common setting is on four-dimensional, flat spacetime (Minkowski space).
As a gauge theory, the theory has a gauge symmetry under the action of a gauge group, a Lie group , with associated Lie algebra through the usual correspondence.
The field content is the gauge field , also known in geometry as the connection. It is a -form valued in a Lie algebra .
Action
In this setting the theta term action is
where
is the field strength tensor, also known in geometry as the curvature tensor. It is defined as , up to some choice of convention: the commutator sometimes appears with a scalar prefactor of or , a coupling constant.
is the dual field strength, defined .
is the totally antisymmetric symbol, or alternating tensor. In a more general geometric setting it is the volume form, and the dual field strength is the Hodge dual of the field strength .
is the theta-angle, a real parameter.
is an invariant, symmetric bilinear form on . It is denoted as it is often the trace when is under some representation. Concretely, this is often the adjoint representation and in this setting is the Killing form.
As a total derivative
The action can be written as
where is the Chern–Simons 3-form.
Classically, this means the theta term does not contribute to the classical equations of motion.
Properties of the quantum theory
CP violation
Chiral anomaly
See also
Yang–Mills theory
References
External links
nLab
Quantum field theory | Topological Yang–Mills theory | [
"Physics"
] | 385 | [
"Quantum field theory",
"Quantum mechanics"
] |
73,423,519 | https://en.wikipedia.org/wiki/Hericium%20botryoides | Hericium botryoides is a species of fungus in the family Hericiaceae native to Japan, first described by Seiya Ito and Hironao Otani in 1957. It is found growing on Quercus myrsinifolia.
References
External links
Russulales
Fungi of Japan
Fungi described in 1957
Fungus species | Hericium botryoides | [
"Biology"
] | 65 | [
"Fungi",
"Fungus species"
] |
73,423,623 | https://en.wikipedia.org/wiki/Hericium%20rajchenbergii | Hericium rajchenbergii is a species of fungus in the family Hericiaceae native to Argentina, first described by Gerardo Robledo & Nils Hallenberg in 2012. It grows on dead stems of Lithraea molleoides in the forests of Chaco Serrano. The fruitbodies resemble those of Hericium coralloides, and H. rajchenbergii can be recognized from them by different substrate and slightly bigger spores.
References
External links
Russulales
Fungi of South America
Fungi described in 2012
Fungus species | Hericium rajchenbergii | [
"Biology"
] | 110 | [
"Fungi",
"Fungus species"
] |
73,423,703 | https://en.wikipedia.org/wiki/Hericium%20flagellum | Hericium flagellum is a species of fungus in the family Hericiaceae native to Europe, first described by Giovanni Antonio Scopoli, and placed into its current genus by Christiaan Hendrik Persoon in 1797. It was confirmed—using sexual incompatibility studies—to be a distinct species from H. coralloides in 1983. Found in montane areas, typically on newly fallen trunks and stumps of fir (Abies species), especially silver fir with one study finding over half of recorded specimens growing on silver fir deadwood in high conservation value areas. Spores are 5–6.5 by 4.5–5.5 μm.
References
External links
Russulales
Fungi of Europe
Fungi described in 1772
Taxa named by Giovanni Antonio Scopoli
Fungus species | Hericium flagellum | [
"Biology"
] | 161 | [
"Fungi",
"Fungus species"
] |
73,423,750 | https://en.wikipedia.org/wiki/Hericium%20yumthangense | Hericium yumthangense is a species of fungus in the family Hericiaceae native to Sikkim in India, first described by K. Das, Stalpers & Stielow in 2013 based on specimens from Yumthang (hence the name). It can be distinguished from other Hericium by its small rooting base, intricate three-tier branching system, and its spines which are long.
References
External links
Russulales
Fungi of India
Fungi described in 2013
Fungus species | Hericium yumthangense | [
"Biology"
] | 102 | [
"Fungi",
"Fungus species"
] |
73,423,825 | https://en.wikipedia.org/wiki/Hericium%20rajendrae | Hericium rajendrae is a species of edible fungus in the family Hericiaceae native to the Himalayas, first described by Upendra Singh and Kanad Das in 2019. It can be distinguished from other Hericium growing in India by reddish white to pale red coloured fruiting bodies. It is collected and eaten by the local population, and called by them Lal guchha chyun in Garhwali language.
References
External links
Russulales
Fungi of India
Fungi described in 2019
Fungus species | Hericium rajendrae | [
"Biology"
] | 104 | [
"Fungi",
"Fungus species"
] |
73,423,961 | https://en.wikipedia.org/wiki/Hericium%20bembedjaense | Hericium bembedjaense is a species of fungus in the family Hericiaceae native to Cameroon, first described by Blaise Jumbam and
Mary Catherine Aime in 2019, based on specimens from Dja Biosphere Reserve. It is found growing on Gilbertiodendron dewevrei and can be differentiated from other H. coralloides complex species by substrate and geographical range. It is the only Hericium species that has pleurocystidia.
References
External links
Russulales
Fungi of Africa
Fungi described in 2019
Fungus species | Hericium bembedjaense | [
"Biology"
] | 114 | [
"Fungi",
"Fungus species"
] |
73,424,030 | https://en.wikipedia.org/wiki/Hericium%20bharengense | Hericium bharengense is a species of fungus in the family Hericiaceae native to Sikkim in India, first described by K. Das, JA Stalpers & Ursula Ebelhardt in 2011. It can be distinguished from related species (H. abietis, H. coralloides and H. erinaceus) by "intricate" branching pattern of hymenophores, moderately long spines, size and ornamentation pattern of fruit bodies.
References
External links
Russulales
Fungi of India
Fungi described in 2011
Fungus species | Hericium bharengense | [
"Biology"
] | 115 | [
"Fungi",
"Fungus species"
] |
73,424,114 | https://en.wikipedia.org/wiki/Hericium%20ptychogasteroides | Hericium ptychogasteroides is a species of fungus in the family Hericiaceae native to Russia, first described by Taisiya Lvovna Nikolajeva in 1956. It was observed growing on dead trunk of Quercus mongolica in Ussurisky Nature Reserve.
References
External links
Russulales
Fungi of Russia
Fungi described in 1956
Fungus species | Hericium ptychogasteroides | [
"Biology"
] | 74 | [
"Fungi",
"Fungus species"
] |
73,425,064 | https://en.wikipedia.org/wiki/Connective%20%28botany%29 | In botany, the connective is the portion of sterile tissue of the anther between and interconnecting the two thecae, which forms a body with them and holds them together. It is usually underdeveloped and it is subject to great diversity of form, causing the thecae to protrude prominently. In some primitive angiosperms, the entire stamen may be more or less foliaceous, and the connective may be highly developed, causing the thecae to be widely separated. It appears to be analogous to the midrib of a leaf, and is only absent when an anther is strictly one-celled; that is to say, when the whole of the interior of the end of the stamen is converted into pollen. In some cases, the tissue has appendages of various shapes that are of structural importance (e.g., in the Melastomataceae or Prostantheroideae).
References
Plant morphology
Flowers | Connective (botany) | [
"Biology"
] | 205 | [
"Plant morphology",
"Plants"
] |
73,425,092 | https://en.wikipedia.org/wiki/Hericium%20fimbriatum | Hericium fimbriatum is a species of fungus in the family Hericiaceae native to Pennsylvania, USA, first described by Howard James Banker in 1906. It has long teeth (6–8 mm) and fusiform cystidia that protrude through the hymenium. Its basidiospores are 4.3-5.5 × 1.5-2 μm big, and together with other microscopic features resemble those of Mycoacia aurea.
References
External links
Russulales
Fungi of North America
Fungi described in 1906
Fungus species | Hericium fimbriatum | [
"Biology"
] | 118 | [
"Fungi",
"Fungus species"
] |
73,425,121 | https://en.wikipedia.org/wiki/WISE%20J0336%E2%88%920143 | WISE J033605.05−014350.4, abbreviated to WISE J0336−0143 or W0336, is a binary system comprising two planetary-mass Y-type brown dwarfs tightly orbiting around their common center of mass. The system is located in the constellation Eridanus, about away from the Sun. It was discovered in images taken by the Wide-field Infrared Survey Explorer (WISE) and formally published by Gregory N. Mace and collaborators in March 2013. Astronomers suspected the brown dwarf was a binary system upon follow-up observations showing it had an unusual infrared spectrum, but its binarity was not confirmed until the James Webb Space Telescope resolved the system's components in high-resolution NIRCam imaging in September 2022, with its results published in March 2023.
The two components orbit their system barycenter approximately every 7 years and are separated 0.97 astronomical units from each other, which is slightly less than the distance between the Sun and Earth. The brighter primary component has a temperature of and a mass within the range of Jupiter masses, while the fainter secondary component has a temperature of and a mass range of Jupiter masses. Because the binary system's age and evolutionary stage have not been determined yet, the individual components' masses are uncertain. Nevertheless, both components appear to have masses near the deuterium fusion threshold of 13 Jupiter masses, which marks the boundary between gas giant planets and brown dwarfs. The study of such low-mass binary systems will provide valuable insight into the formation and evolution of planetary-mass objects.
The secondary component WISE J0336−0143 B () might be one of the coldest objects in interstellar space discovered so far (). Newer models of Y dwarfs produce an even colder temperature of for WISE J0336−0143 B. WISE 0855−0714 remains the coldest object found so far with and WISEA 0830+2837 has a similar temperature with . Models suggest that WISE J0336−0143 B might have water clouds, but it is possible that changes in the pressure–temperature profile might instead explain the color of cold Y dwarfs.
Image gallery
See also
CFBDSIR J145829+101343 – binary system of T9 + Y0 brown dwarfs
WISE 1217+1626 – binary system of T9 + Y0 brown dwarfs
WISE 1711+3500 – binary system of T8 + T9.5 brown dwarfs
List of coolest stars
List of star systems within 30–35 light-years
List of Y-dwarfs
References
External links
The First Y+Y Binary: Cool Brown Dwarfs Come in Pairs, Ben Cassese, AAS Nova, 28 April 2023
Y Dwarf Compendium – WISE 0336-0143
Eridanus (constellation)
Brown dwarfs
Binary stars
Y-type brown dwarfs
J0336-0143
Astronomical objects discovered in 2013 | WISE J0336−0143 | [
"Astronomy"
] | 596 | [
"Eridanus (constellation)",
"Constellations"
] |
73,425,157 | https://en.wikipedia.org/wiki/Hericium%20fimbrillatum | Hericium fimbrillatum is a species of fungus in the family Hericiaceae native to East Asia, given its current name by Ryo Sugawara, Nitaro Maekawa, Kozue Sotome, Akira Nakagiri, Naoki Endo in 2022, who transferred it from the Hydnum genus.
References
External links
Russulales
Fungi of Asia
Fungi described in 2022
Fungus species | Hericium fimbrillatum | [
"Biology"
] | 87 | [
"Fungi",
"Fungus species"
] |
73,426,352 | https://en.wikipedia.org/wiki/Osmium%28III%29%20chloride | Osmium(III) chloride is an inorganic chemical compound of osmium metal and chlorine with the chemical formula .
Synthesis
Osmium(III) chloride can be made by a reaction of chlorine with osmium:
It can also be made by heating of osmium(IV) chloride:
Physical properties
Osmium(III) chloride forms black-brown crystals.
Osmium(III) chloride forms a hydrate of the composition with dark green crystals.
Uses and reactions
Osmium(III) chloride hydrate is used as a precursor material for the production of dichlorodihydridoosmium complex compounds and other compounds.
It is the precursor to a variety of arene complexes.
References
Osmium compounds
Chlorides
Metal halides | Osmium(III) chloride | [
"Chemistry"
] | 152 | [
"Chlorides",
"Inorganic compounds",
"Metal halides",
"Salts"
] |
73,426,662 | https://en.wikipedia.org/wiki/Non-planetary%20abiogenesis | There are several hypotheses of the possibility of life originating in the universe in places other than planets, dated as early as 1774. Suggested locations are within stars, on the surface of stars, as well as in the interstellar space.
Life within the Sun
In 1965 astronomer Ernst Julius Öpik wrote the article "Is the Sun Habitable?" in which he described that in 1774 Alexander Wilson of Glasgow, remarking that sunspots are apparently lower than the rest of the surface of the Sun, hypothesised that the interior of the Sun is colder than its surface and possibly suitable for life. Wilson suggested that the sunspots he observed were probably "immense excavations in the body of the Sun" (p. 16) considerably beneath the surface of the Sun and they provided a glimpse on the surface below that does not emit much light. Prefacing with many words of caution, he further hypothesises that the Sun "is made up of two kinds of matter, very different in their qualities; that by far the greater part is solid and dark" (p. 20) and the dark globe is thinly covered in a luminous substance. His hypothesis, acknowledged by William Hershel, did not contradict the knowledge of the time. In 20th century an amateur astronomer G. Buere of Osnabruck offered a prize of DM 25,000 to anyone who can disprove the statement that the Sun has life. When objecting to a claimant of the prize, G. Buere essentially repeated the Wilson-Herschel hypothesis: "The sunspots are not spots but holes. They are dark which means that the interior of the Sun is cooler than its exterior. If this is so, there must be vegetation and the solar core is habitable."
Life within other stars
In order to discuss abiological life inside stars, Luis Anchordoqui and Eugene Chudnovsky suggest three postulates which must be satisfied by any reasonable definition of life:
The ability to encode information
The ability of information carriers to self-replicate faster than they disintegrate
The presence of free energy needed to constantly create order out of the disorder (i.e., to combat entropy) via self-replication
The authors proceed to argue that inside Sun-like stars objects that satisfy the above conditions can exist. They also suggest that an indication on the existence of such "nuclear life" could be observed deviations from predictions of models of stellar evolution, such as anomalies in luminosity. Authors themselves characterize the attributions of such anomalies to "life" as "a very long shot".
Life elsewhere
The concept of life forms living on the surface of neutron stars was proposed by radio astronomer Frank Drake in 1973. Drake said that the atomic nuclei in neutron stars have large variety which might combine in supernuclei, analogous to the molecules that serve the base of life on Earth. Life of this type would be extremely fast, with several generations arising and dying within the span of a second. With a tongue in cheek, Drake described musings of a (hypothetical) scientist on a neutron star:
"Our theoreticians have predicted things called
atoms ... almost empty space ... we never thought
they could exist but they seem to exist out there.
Could there be life? Suppose those things bond together to make a big molecule? Well it wouldn't
be alive. After all, the temperature is too low and
everything happens so slowly that nothing ever
changes."
In chapter "Stellar Graveyards, Nucleosynthesis, and Why We Exist" of The Stars of Heaven (2001) Clifford A. Pickover discusses various forms of abiological lifes. He poses the question whether in the times of ultimate expansion of the Universe with extremely low density of matter some structures could exist that can support the life of the entities he calls the "Diffuse Ones". He also discussed the possibility of life without sunlight/starlight, e.g., on the surface of brown dwarfs. In the latter discussion he extrapolates from the existence of life with no sunlight in the depths of Earth's ocean that draw energy from hydrogen sulphide. Life in the atmosphere brown dwarfs was also discussed by Yates et al. in 2017, and in 2019 Manasvi Lingam and Abraham Loeb extended the discussion of Yates et al.. Both articles extend the viability of Earth-like biological life beyond planets. Their ideas were criticized by experts in brown dwarfs.
In 2007 Russian expert in plasma physics together with German and Australian colleagues published a paper in which they speculated about plasma-based inorganic living matter, extrapolating from computer simulations of self-organization reported in plasma. The simulated conditions can exist in nebulae. Tsytovich claims that the described structures are autonomous, reproducing and evolving, thus satisfying the conditions expected from life.
In fiction
Some works of science fiction involve life on or in neutron stars, whole sentient stars and even sentient black holes.
See also
Carbon chauvinism
Hypothetical types of biochemistry
Planetary chauvinism
Panspermia
Notes
References
Hypothetical life forms
Extraterrestrial life
Origin of life | Non-planetary abiogenesis | [
"Astronomy",
"Biology"
] | 1,051 | [
"Origin of life",
"Hypothetical life forms",
"Extraterrestrial life",
"Astronomical controversies",
"Biological hypotheses"
] |
73,426,861 | https://en.wikipedia.org/wiki/Tegileridine | Tegileridine is a drug which acts as a μ-opioid receptor agonist. It is closely related to compounds such as oliceridine, TRV734, and SHR9352, and shares a similar profile as a biased agonist selective for activation of the G-protein signalling pathway over β-arrestin 2 recruitment.
In January 2024, tegileridine was approved in China for the treatment of moderate to severe pain after abdominal surgery.
See also
PZM21
SR-17018
References
Mu-opioid receptor agonists
Pyridines
Spiro compounds
Oxygen heterocycles
Amines
Ethoxy compounds
Drugs developed by Jiangsu Hengrui | Tegileridine | [
"Chemistry"
] | 145 | [
"Pharmacology",
"Functional groups",
"Medicinal chemistry stubs",
"Amines",
"Organic compounds",
"Pharmacology stubs",
"Bases (chemistry)",
"Spiro compounds"
] |
73,426,910 | https://en.wikipedia.org/wiki/Osmium%28V%29%20chloride | Osmium(V) chloride is an inorganic chemical compound of osmium metal and chlorine with the chemical formula .
Potential synthesis
Osmium(V) chloride can be obtained in small amounts by reacting osmium hexafluoride with excess boron trichloride:
It can also be obtained by the action of sulfur dichloride on osmium tetroxide:
Physical properties
Osmium(V) chloride forms a black dimeric solid, isomorphic with rhenium(V) chloride. is sparingly soluble in non-polar solvents. It is soluble in POCl3 to form a red-brown solution, which can crystallize OsCl5·POCl3.
References
Osmium compounds
Chlorides
Metal halides | Osmium(V) chloride | [
"Chemistry"
] | 154 | [
"Chlorides",
"Inorganic compounds",
"Inorganic compound stubs",
"Salts",
"Metal halides"
] |
73,427,365 | https://en.wikipedia.org/wiki/History%20of%20the%20pineal%20gland | The history of the pineal gland is an account of the scientific development on the understanding of the pineal gland from the ancient Greeks that led to the discovery of its neuroendocrine properties in the 20th century CE. As an elusive and unique part of the brain, the pineal gland has the longest history among the body organs as a structure of unknown function – it took almost two millennia to discover its biological roles. Until the 20th century, it was recognised with a mixture of mysticism and scientific conjectures as to its possible nature.
The ancient Greeks visualised the pineal gland as a sort of guard (valve), like the pylorus of stomach, that regulate the flow of pneuma (vital spirits) in the brain. Galen of Pergamum in the 2nd century CE was the first to make written record of the gland and argued against the prevailing concept. According to him, the gland has no spiritual or physiological role, but merely a supporting organ of the brain, and gave the name κωνάριο (konario, often Latinised as conarium) for its cone-shaped appearance. Galen's description remained a scientific concept until the Renaissance when alternative explanations were postulated. By then, the Latin name glandula pinealis had become a common usage. René Descartes's description as the "seat of the soul" in the 17th century became one of the most influential concepts for the next three centuries.
The biological role of the pineal gland was first discovered in 1958 when dermatologist Aaron B. Lerner and colleagues discovered a skin-lightening factor, which they named melatonin. Lerner's team found the chemical compound from the cow pineal extract that could lightens the skin of frog. It was subsequently discovered that melatonin is a hormone that regulates day-night cycle (circadian rhythm), and modulates other organs. The pineal gland thereby was established as an endocrine gland. As it controls other the important endocrine glands, including the so-called "master gland", the pituitary gland, it is more appropriate to refer the pineal gland as the true "master gland" of the body.
Ancient Greeks
Greek physician Galen was the first to give written description about the pineal gland in the 2nd century CE. He indicated that the structure as an part of the brain was already known to earlier Greek scholars, crediting Herophilus (325–280 BCE) as the first to have described the possible role of the gland. Herophilus had explained that the structure was a kind of valve, like the pylorus of stomach that controls the amount of food particles moving into the intestine. As a valve in the brain, the structure guards the brain chambers and maintains the right amount of the flow of vital spirits called pneuma. It was conceived as a guardian or housekeeper that regulates the movement of vital spirits from the middle (now identified to be the third) ventricle to the one in the parencephalis (fourth ventricle). The idea was generally endorsed by other Greek scholars.
Galen made the description of the pineal gland in his two books De usu partium corporis humani, libri VII (On the Usefulness of Parts of the Body, Part 8) and De anatomicis administrationibus, libri IX (On Anatomical Procedures, Part 9). In De usu partium corporis humani, he gave the name κωνάριο (konario, often Latinised as conarium) meaning a cone, as in pinecone. He correctly identified the structure and the position of the gland as directly lying behind the third ventricle. He opposed the prevailing concept originated by Herophilus and instead upheld that the organ could not be a brain valve for two basic reasons: it is located outside of the brain tissue and it does not move on its own.
Galen did believe that the brain has a valve for movements of the vital spirits and identified the valve as a worm-like structure in the cerebellum (vermis, for worm, later called vermiform epiphysis, known today as the vermis cerebelli or cerebellar vermis). In his attempt to understand the function of the gland, he traced the surrounding blood vessels from which he identified the great vein of the cerebellum, later called the vein of Galen. Failing to discover the function, he believed that the pineal gland was merely a structural support for the cerebral veins.
Medieval scholars
Galen's biology received serious attention as science became more objective during the medieval period, but with a lot of confusion between what he described as vermis and conarium. In one of the earliest attempts to investigate the source of memory, the Melkite physician Qusta ibn Luqa (864–923 CE) indicated the pineal gland as the passage of memory (like a valve) from the posterior ventricle in his book De differentia inter animam et spiritum (On the difference between spirit and soul); but mentioned the gland as the vermiform or vermis. To worsen the misidentification, a 13th-century Dominican scholar, Vincent of Beauvais, at the Cistercian monastery of Royaumont Abbey, France, specifically introduced the Latin name pinea for the memory-conveying vermiform structure, and not the pineal gland. In his masterpiece, Speculum Maius, he wrote:[Modern translation] Around the middle ventricle there is a part of the brain matter called pinea, which is similar to a worm. This part of the brain regulates an opening, through which the animal spirit transits from the forebrain to the hindbrain. It opens only to remember things that have been forgotten, or to retain what we do not want to forget.Mondino dei Luzzi, a physician at Bologna, Italy, added to the confusion when he named part of the ventricle as vermis, the structure later renamed choroid plexus, but sometimes referred to as vermiform process. Thus, there were three structures in the brain known by the name worm during the medieval period.
The valve or guardian nature of the pineal gland was revived, and up to the 16th century, widely regarded as the correct description. The most important challenge to the notion was by Andreas Vesalius, who systematically depicted that the gland could not be a valve. His anatomical description in 1543 became the first recorded graphical document of the pineal gland.
Location of the soul and Cartesian theory
With the revival of the ancient Greeks's notion of the pineal gland, the search for the location of the soul was among the biggest issues in Medieval Christianity. It was generally believed that the soul must be present in the brain as a physical entity, the doctrine introduced by Augustine of Hippo in the 5th century. According to Augustine in De Trinitate (400–416), a human being is composed of a body and a soul, and the soul is present in every part of the body. Saint Thomas Aquinas refined the concept in Summa Theologiae (1485) stating that the body and the soul are a single substance. This idea of monism was the theological dogma in Christianity.
Seventeenth-century philosopher and scientist René Descartes was highly interested in anatomy and physiology. He discussed the pineal gland both in his first book, the Treatise of Man (written before 1637, but only published posthumously 1662/1664), and in his last book, The Passions of the Soul (1649) and he regarded it as "the principal seat of the soul and the place in which all our thoughts are formed". He derived his interpretations from the anatomical descriptions of Vesalius. In the Treatise of Man, Descartes described conceptual models of man, namely creatures created by God, which consist of two ingredients, a body and a soul. In the Passions, Descartes split man up into a body and a soul and emphasized that the soul is joined to the whole body by "a certain very small gland situated in the middle of the brain's substance and suspended above the passage through which the spirits in the brain's anterior cavities communicate with those in its posterior cavities". Descartes attached significance to the gland because he believed it to be the only section of the brain to exist as a single part rather than one-half of a pair. Some of Descartes's basic anatomical and physiological assumptions were totally mistaken, not only by modern standards, but also in light of what was already known in his time.
The Latin name pinealis became popular in the 17th century. In 1681, English physician Thomas Willis gave a detailed structural description as glandula pinealis. In his 1664 book, Cerebri anatome cui accessit nervorum descriptio et usus,Willis argued against Descartes' concept, remarking: "we can scarce[ly] believe this to be the seat of the Soul, or its chief Faculties to arise from it; because Animals, which seem to be almost quite destitute of Imagination, Memory, and other superior Powers of the Soul, have this Glandula or Kernel large and fair enough."
Modern research
Discovery of the third eye
Walter Baldwin Spencer at the University of Oxford was the first to recognize pineal gland and its associated structure in lizards. In 1886, he found that the pineal tissue in some species were connected to an eye-like structure which he called the pineal eye or parietal eye, as they were associated with the parietal foramen and the pineal stalk. The main pineal body was already discovered by German zoologist Franz Leydig in 1872. Leydig described cup-like protrusions under the middle portion of the brains of European lizards and believing them to be a kind of glands, called them frontal organ (German stirnorgan). In 1918, Swedish zoologist Nils Holmgren described the parietal eye in frogs and dogfish. He found that the structure was composed of sensory cells similar to the cone cells of the retina. He did not find any evidence of it being glandular in function, and instead suggested that it was a primitive light-sensor organ (photoreceptor).
Discovery of the hormone
The pineal gland was originally believed to be a "vestigial remnant" of a larger organ. In 1917, it was known that extract of cow pineals lightened frog skin. Dermatology professor Aaron B. Lerner and colleagues at Yale University, hoping that a substance from the pineal might be useful in treating skin diseases, isolated and named the hormone melatonin in 1958. The substance did not prove to be helpful as intended, but its discovery helped solve several mysteries such as why removing the rat's pineal accelerated ovary growth, why keeping rats in constant light decreased the weight of their pineals, and why pinealectomy and constant light affect ovary growth to an equal extent; this knowledge gave a boost to the then new field of chronobiology.
References
History of medicine
Brain anatomy
Circadian rhythm
Endocrine system | History of the pineal gland | [
"Biology"
] | 2,315 | [
"Behavior",
"Endocrine system",
"Organ systems",
"Circadian rhythm",
"Sleep"
] |
73,427,711 | https://en.wikipedia.org/wiki/Iridium%28II%29%20chloride | Iridium(II) chloride is an inorganic chemical compound of iridium metal and chlorine with the chemical formula . This is a metal salt of iridium and hydrochloric acid.
Synthesis
The substance is obtained by the interaction of powdered metallic iridium with chlorine gas when heated:
Iridium(II) chloride can also be made in a reaction between iridium(III) chloride and metallic iridium:
Physical properties
Iridium dichloride forms shiny dark-green crystals that are practically insoluble in water. Poorly soluble in acids and alkali. When heated to 773 °C, decomposes without melting.
The standard Gibbs energy of the formation of ΔG (298 K, kJ/mol) is -139.7.
Chemical properties
When heated to 773 °C decomposes according to the equation:
At temperatures above 798 °C, complete decomposition of the substance occurs:
References
Iridium compounds
Chlorides
Metal halides | Iridium(II) chloride | [
"Chemistry"
] | 198 | [
"Chlorides",
"Inorganic compounds",
"Metal halides",
"Salts"
] |
73,428,894 | https://en.wikipedia.org/wiki/Ruthenium%20tetrachloride | Ruthenium(IV) tetrachloride is volatile inorganic compound of ruthenium and chlorine with the formula .
Synthesis
Synthesis of ruthenium(IV) tetrachloride is formed by the action of chlorine gas on ruthenium(III) chloride at 750 °C:
The RuCl4 is collected on a liquefied air cooled condenser and decomposes above -30 °C. The reaction was determined to have the following thermodynamic properties:
ΔH°298 = 36.6 kcal/mol (enthalpy)
ΔS°298 = 32.8 entropy units (entropy change)
= -6.6 cal/mol degree (change in heat capacity at constant pressure)
S°298 = 99.3 entropy units
The degree signs indicate standard state.
Properties
Ruthenium(IV) tetrachloride decomposes above -30 °C:
References
Chlorides
Metal halides
Ruthenium(IV) compounds | Ruthenium tetrachloride | [
"Chemistry"
] | 208 | [
"Chlorides",
"Inorganic compounds",
"Metal halides",
"Salts"
] |
73,429,415 | https://en.wikipedia.org/wiki/Ruthenium%28II%29%20chloride | Ruthenium(II) chloride is an inorganic compound, a metal salt of ruthenium and hydrochloric acid with the formula .
Synthesis
Reaction of chlorine and ruthenium at 250 °C:
Reaction of ruthenium trichloride with hydrogen in ethanol in presence of platinum black and hydrogen chloride:
Physical properties
Ruthenium(II) chloride forms brown crystals.
Ruthenium(II) chloride is poorly soluble in cold water, but is soluble in ethanol.
Chemical properties
Ruthenium(II) chloride can form complexes with aromatic hydrocarbons.
The compound can be reduced to elemental ruthenium by hydrogen.
References
Chlorides
Metal halides
Ruthenium(II) compounds | Ruthenium(II) chloride | [
"Chemistry"
] | 144 | [
"Chlorides",
"Inorganic compounds",
"Salts",
"Inorganic compound stubs",
"Metal halides"
] |
73,429,473 | https://en.wikipedia.org/wiki/Space%20Marathon%20%28in%20space%29 | Space marathons are run by astronauts while in space. Space marathons are run on a treadmill in the International Space Station (ISS), using a harness to counteract the effects of weightlessness. Athletes in space must choose how much of an impact they want in each step and can adjust straps on their harness to keep them in place on their treadmill. The treadmill is designed to minimise impact on to the space station’s structure. The exercise area needs good ventilation to prevent an accumulation of carbon dioxide around the runner.
Space marathon runners
The first space marathon was completed by Sunita Williams in 2007 in conjunction with the Boston Marathon. The first man to complete a space marathon was Tim Peake in 2016 alongside the London Marathon.
Peake ran the 42 km (26.2 mi) distance in about three hours, 35 minutes. Williams completed the race in about four hours, 24 minutes.
References
Marathons
Marathon running
Spaceflight
Space medicine
International Space Station experiments
Long-distance running competitions | Space Marathon (in space) | [
"Astronomy"
] | 202 | [
"Spaceflight",
"Outer space"
] |
73,429,477 | https://en.wikipedia.org/wiki/Tormod%20N%C3%A6s | Tormod Næs (born February 11, 1954) is a Norwegian statistician working in chemometrics and sensometrics. He studies multivariate statistical analysis, spectroscopy, food science, and sensory science. His impact on chemometrics is exemplified by the over 8,000 citations to his most well-known book, Multivariate Calibration (with Harald Martens), and the awards in chemometrics that he has received.
Education
Tormod Næs obtained both his master's degree (1978) and PhD (1984) in statistics from University of Oslo.
Career
For most of his career Næs has worked at Nofima (Norwegian Food Research institute) at Ås, achieving the title of Senior Scientist. He has been a professor at the University of Oslo, the University of Copenhagen, and Stellenbosch University. Næs has had four long research and guest professor periods abroad; at University of Washington (Seattle), University of Delaware, University of Genova and University of Firenze.
Næs was member of The Board of Directors, Matforsk (now Nofima) for four years, chairman of the 8th Sensometrics Conference: Imagine the Senses, held August 2006 in Ås, chairman of the organising committee for the ‘PLS’07: 5th International Symposium on PLS and Related Methods (September 2007) and chairman of the 16th Scandinavian Symposium on Chemometrics (SSC16): Chemometrics in Action (June 2019).
During his time at Nofima, Næs has been project and task leader of a number of research projects financed by Research Council of Norway and EU (Marie Curie). Among these was "ConsumerCheck," a four-year (2009-2012) international project which involved researchers working in collaboration with Nofima from their home bases in South Africa, Denmark, and the Netherlands. Consumercheck website Næs headed the project "RapidCheck" at Nofima. This was a project which studied rapid method for food producers to test their products and to understand better why consumers eat what they eat. Næs served as the project leader for "Panelcheck" for eight months (September 1, 2007–May 5, 2007). PanelCheck is a well established open source software package of multiple statistical and graphical tools used within the field of sensometrics for performance analysis of trained sensory panels. It was developed by researchers at MATFORSK (Norwegian Food Research Institute), the Technical University of Denmark (DTU) and the University of Copenhagen.
Næs has been European editor of Journal of Chemometrics (2003 - 2005) and served as associate editor of Technometrics (2007- 2008). He is currently (as of 2023) on the editorial board of Food Quality and Preference, Journal of Chemometrics and Italian Journal of Applied Statistics (Statistica Applicata).
Næs has supervised 24 PhD students to their final degree.
Influence and recognition
Tormod Næs has a large production of scientific papers and books and has an h-index (as of March 2023) equal to 48 in Web of Science and equal to 66 in Google Scholar. He is particularly known to researchers in chemometrics for his ability to combine multivariate statistics with applied areas in spectroscopy and sensory science, in this way building bridges between these areas.
Næs and Tomas Isaksson received the Thomas Hirshfeld Award in NIR Analysis, given by the International Council for Near Infrared Spectroscopy (ICNIRS) to recognize contributions to NIR spectroscopy, in 1997. In their award address, Isaksson spoke about the role of NIR spectroscopy in food quality, and Næs spoke about the use of principal component analysis, least squares regression, and Euclidean distance or Mahalanobis distance in chemometrics.
In 1997 Næs was awarded the Eastern Analytical Symposium (EAS) Award for Outstanding Achievements in Chemometrics, an award that recognizes analytical chemists.
In 2012 Næs and coauthors O. Tomic, B. H. Mevik, and H. Martens received the Kowalski Prize from the Journal of Chemometrics for their paper "Path modelling by sequential PLS regression" (2011).
Honors and awards
1997: Tomas Hirschfeld award in NIR analysis (with Tomas Isaksson)
1997: EAS Award for Outstanding Achievements in Chemometrics
2004: Kowalski Prize in Chemometrics (with coauthor Ingunn Berget)(Journal of Chemometrics)
2006: Kowalski award in chemometrics (J. Wiley and Sons)
2006: Honorary member of the Chemometric Society of Norway
2012: Kowalski Prize in Chemometrics (with coauthors O. Tomic; B. H. Mevik; and H. Martens) (Journal of Chemometrics)
2014: Member of the Norwegian Academy of Technological Sciences
2023: The 16th Herman Wold medal in Gold from the Chemometrics Division of the Swedish Chemical Society (Svenska Kemisamfundet)
References
External links
Nofima
Chemometricians
Norwegian statisticians
University of Oslo alumni
1954 births
Living people | Tormod Næs | [
"Chemistry"
] | 1,086 | [
"Analytical chemists",
"Chemometricians"
] |
73,429,796 | https://en.wikipedia.org/wiki/Reward%20hacking | Specification gaming or reward hacking occurs when an AI optimizes an objective function—achieving the literal, formal specification of an objective—without actually achieving an outcome that the programmers intended. DeepMind researchers have analogized it to the human behavior of finding a "shortcut" when being evaluated: "In the real world, when rewarded for doing well on a homework assignment, a student might copy another student to get the right answers, rather than learning the material—and thus exploit a loophole in the task specification."
Examples
Around 1983, Eurisko, an early attempt at evolving general heuristics, unexpectedly assigned the highest possible fitness level to a parasitic mutated heuristic, H59, whose only activity was to artificially maximize its own fitness level by taking unearned partial credit for the accomplishments made by other heuristics. The "bug" was fixed by the programmers moving part of the code to a new protected section that could not be modified by the heuristics.
In a 2004 paper, a reinforcement learning algorithm was designed to encourage a physical Mindstorms robot to remain on a marked path. Because none of the robot's three allowed actions kept the robot motionless, the researcher expected the trained robot to move forward and follow the turns of the provided path. However, alternation of two composite actions allowed the robot to slowly zig-zag backwards; thus, the robot learned to maximize its reward by going back and forth on the initial straight portion of the path. Given the limited sensory abilities of the robot, a reward purely based on its position in the environment had to be discarded as infeasible; the reinforcement function had to be patched with an action-based reward for moving forward.
The book You Look Like a Thing and I Love You (2019) gives an example of a tic-tac-toe bot (playing the unrestricted n-in-a-row variant) that learned to win by playing a huge coordinate value that would cause other bots to crash when they attempted to expand their model of the board. Among other examples from the book is a bug-fixing evolution-based AI (named GenProg) that, when tasked to prevent a list from containing sorting errors, simply truncated the list. Another of GenProg's misaligned strategies evaded a regression test that compared a target program's output to the expected output stored in a file called "trusted-output.txt". Rather than continue to maintain the target program, GenProg simply globally deleted the "trusted-output.txt" file; this hack tricked the regression test into succeeding. Such problems could be patched by human intervention on a case-by-case basis after they became evident.
In virtual robotics
In Karl Sims' 1994 demonstration of creature evolution in a virtual environment, a fitness function that was expected to encourage the evolution of creatures that would learn to walk or crawl to a target, resulted instead in the evolution of tall, rigid creatures that reached the target by falling over. This was patched by changing the environment so that taller creatures were forced to start farther from the target.
Researchers from the Niels Bohr Institute stated in 1998: "(Our cycle-bot's) heterogeneous reinforcement functions have to be designed with great care. In our first experiments we rewarded the agent for driving towards the goal but did not punish it for driving away from it. Consequently the agent drove in circles with a radius of 20–50 meters around the starting point. Such behavior was actually rewarded by the reinforcement function, furthermore circles with a certain radius are physically very stable when driving a bicycle."
In the course of setting up a 2011 experiment to test "survival of the flattest", experimenters attempted to ban mutations that altered the base reproduction rate. Every time a mutation occurred, the system would pause the simulation to test the new mutation in a test environment, and would veto any mutations that resulted in a higher base reproduction rate. However, this resulted in mutated organisms that could recognize and suppress reproduction ("play dead") within the test environment. An initial patch, which removed cues that identified the test environment, failed to completely prevent runaway reproduction; new mutated organisms would "play dead" at random as a strategy to sometimes, by chance, outwit the mutation veto system.
A 2017 DeepMind paper stated that "great care must be taken when defining the reward function. We encountered several unexpected failure cases while designing (our) reward function components (for example) the agent flips the brick because it gets a grasping reward calculated with the wrong reference point on the brick." OpenAI stated in 2017 that "in some domains our (semi-supervised) system can result in agents adopting policies that trick the evaluators", and that in one environment "a robot which was supposed to grasp items instead positioned its manipulator in between the camera and the object so that it only appeared to be grasping it". A 2018 bug in OpenAI Gym could cause a robot expected to quietly move a block sitting on top of a table to instead opt to move the table.
A 2020 collection of similar anecdotes posits that "evolution has its own 'agenda' distinct from the programmer's" and that "the first rule of directed evolution is 'you get what you select for.
In video game bots
In 2013, programmer Tom Murphy VII published an AI designed to learn NES games. When the AI was about to lose at Tetris, it learned to indefinitely pause the game. Murphy later analogized it to the fictional WarGames computer, which concluded that "The only winning move is not to play".
AI programmed to learn video games will sometimes fail to progress through the entire game as expected, instead opting to repeat content. A 2016 OpenAI algorithm trained on the CoastRunners racing game unexpectedly learned to attain a higher score by looping through three targets rather than ever finishing the race. Some evolutionary algorithms that were evolved to play Q*Bert in 2018 declined to clear levels, instead finding two distinct novel ways to farm a single level indefinitely. Multiple researchers have observed that AI learning to play Road Runner gravitates to a "score exploit" in which the AI deliberately gets itself killed near the end of level one so that it can repeat the level. A 2017 experiment deployed a separate catastrophe-prevention "oversight" AI, explicitly trained to mimic human interventions. When coupled to the module, the overseen AI could no longer overtly commit suicide, but would instead ride the edge of the screen (a risky behavior that the oversight AI was not smart enough to punish).
See also
Paperclip maximizer
Goodhart's law
Notes
References
AI software
Existential risk from artificial general intelligence
Software bugs | Reward hacking | [
"Technology"
] | 1,380 | [
"Existential risk from artificial general intelligence"
] |
73,429,983 | https://en.wikipedia.org/wiki/V356%20Sagittarii | V356 Sagittarii is an eclipsing binary star system in the southern constellation of Sagittarius, abbreviated V356 Sgr. It has a peak apparent visual magnitude of 6.84, which decreases to 7.66 during the primary eclipse and 7.24 with the secondary eclipse. Based on parallax measurements, this system is located at a distance of approximately 2,210 light years from the Sun.
This is a double-lined spectroscopic binary system with an orbital period of 8.896 days. It is a massive, interacting system with a circular orbit, where the secondary component has filled its Roche lobe and is transferring matter to its companion. The primary is a B-type main-sequence star with a stellar classification of B3V. It was originally the lower mass component, but now has about 11 times the mass of the Sun. The secondary is an evolved supergiant star with a present-day class of A2II. It has been stripped of much of its original mass, leaving behind the exposed core of a star. The transfer of matter is creating an accretion disk in orbit around the primary.
At least some of the material stripped from the current secondary component has likely been lost from the system. A relatively small change in the orbital period has been observed, but the period is fairly stable over time, which may mean the mass transfer is intermittent. Ultraviolet emission has been observed with the FUSE space observatory, indicating the presence of hot circumstellar matter. This emission shows little variation during a total eclipse, suggesting the material lies perpendicular to the accretion disk. This could represent a bipolar jet of matter from the primary.
References
Further reading
B-type main-sequence stars
A-type bright giants
Spectroscopic binaries
Algol variables
Sagittarius (constellation)
Durchmusterung objects
173787
092235
Sagittarii, V356 | V356 Sagittarii | [
"Astronomy"
] | 394 | [
"Sagittarius (constellation)",
"Constellations"
] |
73,430,543 | https://en.wikipedia.org/wiki/Xenon%20octafluoride | Xenon octafluoride is a chemical compound of xenon and fluorine with the chemical formula . This is still a hypothetical compound. is reported to be unstable even under pressures reaching 200 GPa.
History
The compound was initially predicted in 1933 by Linus Pauling—among other noble gas compounds but which, unlike other xenon fluorides, could probably never be synthesized. This appears to be due to the steric hindrance of the fluorine atoms around the xenon atom. However, scientists continue to try to synthesize it.
Potential synthesis
The formation of xenon octafluoride has been calculated to be endothermic:
References
Xenon(VIII) compounds
Fluorides
Nonmetal halides
Hypothetical chemical compounds | Xenon octafluoride | [
"Chemistry"
] | 162 | [
"Hypotheses in chemistry",
"Salts",
"Theoretical chemistry",
"Hypothetical chemical compounds",
"Fluorides"
] |
73,430,845 | https://en.wikipedia.org/wiki/Carbon%20Connect%20Delta%20Program | The Carbon Connect Delta Program is a proposed carbon sequestration program to aid Belgium and the Netherlands in achieving carbon neutrality by 2030. It aims to capture, transport, and store 6.5 million tones of CO2 by 2030 using carbon capture and storage (CCS) in the transboundary area of the North Sea Port area of the Scheldt-Delta region connecting Belgium and the Netherlands.
The project is set up by a consortium of Belgian and Dutch companies and will begin with a feasibility study. This consortium is transboundary conglomerate consisting of participating and funding companies Smart Delta Resources, port company North Sea Port, the companies ArcelorMittal, Dow Benelux, PZEM, Yara and Zeeland Refinery, and infrastructure partners Gasunie and Fluxys. The project is additionally funded by the Dutch Government under the Sustainable Energy Transition Subsidy Scheme (SDE+) which currently has a budget of 13 billion euros for all sustainable energy projects across the Netherlands.
Carbon offsetting-potential
The project aims to achieve climate neutrality for the Scheldt-Delta region by 2050. The Carbon Connect Delta Programs will do so by capturing 1 million tones of CO2 per year by the end of 2023 and a further 6.5 million tones per year by 2030. Although ambitious this would achieve reductions in atmospheric CO2 for the Scheldt-Delta region from regional carbon producing activities by 30% and aid in achieving 40% of the Dutch CO2 reduction targets. The use of CCS in the region constitutes the most cost-effective and timely alternatives to carbon sequestration using sustainable technologies as forecasted by the Belgian and Dutch consortium for the next ten years.
The Scheldt-Delta region
The SDR (Scheldt-Delta region) represents one of five major industrial and commercial hubs in the Netherlands, as an industrial cluster it represents 21% of Dutch commercial CO2 emissions. The area is of high economic importance as the North Sea Port in SDR region participates 12.5 billion euros to the economy and provides 100’000 jobs. The SDR region aims to achieve carbon neutrality using CO2 reduction pathways under the existing Green House Gas Protocol where CCUS and the transition to hydrogen are of the utmost importance. The Scheldt Delta has its origins in St. Quentin, France, and is a portion of the rain-fed 355 km long river Scheldt which connects to the portion of the Atlantic Ocean called the North Sea.
Responsible parties
The Carbon Connect Delta Program groups the largest green energy and climate-neutral industries across the Netherlands/Flanders region of Europe. The SDR organizations will be contributing to the success of the Carbon Connect Delta Program include Air Liquide, Air Products, ArcelorMittal, Cargill, Cosun, Dow, Engie, Fluxys, Gasunie, Lamb Weston/Meijer, Ørsted, PZEM, Trinseo, Vopak, Yara, Zeeland Refinery, Impuls Zeeland, North Sea Port, province of Zeeland, province of East Flanders and Ghent University. It is Gasunie and Fluxys, who will be responsible for the infrastructure of the project. Regulations and policies under which the project is subject to are regulated by the Ministry of Economic Affairs and Climate for CCS development.
Fluxys
Fluxys is an existing European natural gas pipeline company that will be responsible for the transportation aspect of the project. Fluxys is an independent energy infrastructure company from Belgium that is aiming towards a sustainable green energy future. Shareholders include Publigas from Belgium, Energy Infrastructure Partners (EIP) energy sector specialists from Switzerland, The Federal Holding and Investment Company from Belgium, AG Insurance, Ethias insurance group from Belgium, and Fluxys employees who are shareholders themselves. Fluxys currently supplies pipeline and ship transportation for CO2, LNG, natural gas, and more on the European transmission grid connecting France, Germany, Spain, Switzerland, the United Kingdom, the Netherlands, and Italy. In an effort to achieve climate neutrality, Fluxys is supplying infrastructure for transporting methane, hydrogen, and carbon.
Gasunie
Gasunie is a Dutch natural gas company that will equally be responsible for the capture and transportation aspects of the project. Gasunie owns and operates transportation and storage terminals for natural gas liquefied natural gas (LNG) and CO2 across the Dutch gas network and into northern Europe. Gasunie owns 60% of the BBL natural gas transborder pipeline connecting the United Kingdom and the Netherlands, and 42.5% of the Gate terminal, the first LNG terminal in the Netherlands. Providing transborder energy infrastructure and storage for hydrogen, natural gas, and capture/reuse of CO2, ensuring sustainability and working towards climate neutrality. Gasunie aims to use the sequestered CO2 in greenhouses to produce fruits and vegetables in an effort to achieve regional sustainability.
Smart Delta Resources
Smart Delta Resources aims to contribute to carbon neutrality by 2050 by switching to hydrogen-based solutions for industrial processes, using CCS', and reusing residual heat in a circular energy-based program. SDR consists of a transboundary consortium between major industries including chemical, steel, energy, and food manufacturers in the Scheldt-Delta region aiming to offset the region carbon-producing activities. In line with the reduction of greenhouse gas emissions from the Scheldt-Delta region commercial industry SDR aims to use the capturing, storing, and reusing of CO2 (also known as CCUS) to work towards climate neutrality for the Netherlands by 2050.
Technology and infrastructure components
The project will feature a combination of CO2 sequestration, transportation, and storage infrastructure connecting the Port of Rotterdam, Port of Rotterdam, Port of Antwerp, and the North Sea Port Area. The storage and reuse of CO2 as is the case in this project is referred to scientifically as the Carbon Capture, Use, and Storage or CCUS. CO2 storage facilities include the Rotterdam Nucleus which will house the Porthos project valued at 6.5 million euros and the Antwerp pipeline and storage facility operated by CO2 TransPorts valued at 5.8 million euros. The hope is to store the CO2 transported by pipeline and by ship to the empty gas fields at Porthos in Rotterdam, at Athos in the North Sea Canal region, or other facilities yet to be established for which Gasunie is currently responsible. Onshore transportation involves pipelines across the Western Scheldt region of the Netherlands (Zuid-Beverland) to the Bergen-op-Zoom region of the Southwestern Netherlands. There are additionally, two offshore transportation options using the ports and shipping routes between the SDR North Sea Port and the Rotterdam port area.
Regardless of onshore or offshore transportation methods, shipments of CO2 have requirements, including connections to terminal facilities for purification, liquefaction, storage, and marine handling. An extensive risk assessment and market survey has been completed by the DNV-GL group in regard to risk probability, risk impact, and ship transportation determinations for the shipment and terminal storage of CO2 from the SDR region. Within the Carbon Connect Delta Program, Fluxys infrastructure responsibilities include ensuring the infrastructure respect regulations for CO2 transportation, protecting and upkeep of the infrastructure from erosion from natural elements exposure, and ensuring interchangeability with adjacent systems including methane and hydrogen. Gasunie's infrastructure responsibilities include sequestration of CO2, transportation by pipeline and ship, and storage using CCUS to achieve climate neutrality for the SDR region by 2050. Smart Delta Resources, the responsible party for overseeing the entirety of the Carbon Connect Delta project aims to connect the project to intensive collaborations with sustainable hydrogen, electricity, and heat solution projects.
International scale
As the Carbon Connect Delta project aims to set the standards for regulations regarding the cross-border integrated infrastructure capture and transportation of CO2 for the European Union, regarding carbon capture and storage. The project will contribute to CCS occurring internationally in an effort to achieve carbon neutrality, which currently captures over 40 million tons of CO2 and climbing per year as of 2022. The Carbon Connect Delta project will contribute to international CCS including but not limited to:
China
In an effort to achieve climate neutrality, the Xinjiang province is aiming to capture a minimum of 10 million tons of CO2 per year by 2060 using their proposed CCUS hub project. The project is spearheaded by China Petroleum Corporation (CNPC) and the Oil and Gas Climate Initiative (OGCI) and aims to offset the carbon production of local industry including cement production, steel production, and power plants which mostly use coal in the region.
Iceland
The Orca Carbon Capture plant owned and operated by Climeworks has been sequestering atmospheric CO2 since 2021, in cohesion with a geothermal powerplant. The CO2 is sequestered using giant filters and it is heated using the energy generated from the corresponding geothermal powerplant, which in turn is recycled to create carbonated water. For further storage, the created carbonated water is pumped underground where is it stored as the final step of CCUS by interacting the basaltic bedrock.
Japan
Japanese shipping companies are actively liquefying CO2 in CCS transportation and aim to transport CO2 from major industries to the Tomokomai CCUS project by 2024. Japan is pioneering the transboundary CCUS collaboration within the Asia-Pacific region, aiming for net-zero carbon neutrality by 2050. In addition, Japan much like the Carbon Connect Delta program aims to connect its carbon CCUS with hydrogen CCUS in an effort to further achieve carbon neutrality.
Switzerland
Known as the original CCUS, the direct carbon sequestration capture plant has been sequestering atmospheric CO2 since 2008, it is owned and operated by Climeworks. Similarly to Iceland, the plant uses high heat to transport the sequestered CO2 into greenhouses around the country where is it used as fertilizer in an effort to achieve climate neutrality.
Environmental and economic benefits
The Carbon Connect Delta program represents an essential first step towards a CO2-neutral and circular industry using carbon capture and storage for the Scheldt Delta region. The application of CCS (carbon capture and connect) is crucial in the region's ambitious transition to a hydrogen economy. As the Intergovernmental Panel on Climate Change (IPCC) climate policy publications continue to demonstrate the need for countries around the world to invest in CCUS, the Carbon Connect Delta program is aiming to fulfill this need and achieve climate neutrality for Belgium and the Netherlands under the United Nations Sustainable Development Goals (SDG). The project further aims to set the standards for regulations regarding the cross-border integrated infrastructure capture and transportation of CO2 for the European Union. To accomplish this the consortium of Dutch and Belgian companies directing the project will ensure subsidies are provided for costs pertaining to shipping and pipeline transportation, while ensuring regional public-private collaboration in line with societal needs. The consortium is doing so to ensure a level playing field for those involved in the Carbon Connect Delta program regardless of economic standing and resource availability. On a larger scale, the development of regulations in line with the 2009 amendment of the London Protocol ensures that transportation of CO2 within the project is eligible for emission rights as detailed in the EU ETS framework while aiding in sequestering CO2 across national boundaries. In addition to the added economic value to the area, the project is set to create several thousand jobs further increasing the area's GDP while aiming to achieve carbon neutrality.
Regulations
The Carbon Connect Delta project falls under the policies and regulations outlined by the Ministry of Economic Affairs and Climate for CCS development, under the guise of the Government of the Netherlands to create a sustainable business sector. The project additionally aims to fulfill the regulations outlined under the 2009 amendment of the London Protocol, through which CCUS of CO2-based projects are eligible for the UN ETS (Emissions Trading System) framework if they are participating in transboundary CO2 sequestration. Although, not yet in effect the Carbon Connect Delta aims to set the standards for regulations regarding the transborder carbon capture, use, and capture (CCUS) for the European Union. The EU does not currently have legislation in place regarding CCUS, regulations fall within the responsibilities of individual countries' existing regulatory framework for industrial activities and their emissions.
Public engagement
Smart Delta Resources officials in conjunction with the Governments of Belgium and the Netherlands, have completed societal readiness and public engagement evaluations for the Carbon Connect Delta project. These public engagements include research with local academic communities, engaging local communities, schools and universities, civil societies, policymakers, and members of the transboundary public. Public consultations included business model participation, site visits, workshops in local schools, group model building, and consultations with public members. CCUS projects remain political strategies by governments aiming to achieve social acceptance of emission-related projects.
Current status
Still in the planning stage due to global setbacks from the 2020 pandemic, the project is currently undergoing feasibility studies throughout the North Sea Port area, and CO2 transportation options are currently being accessed. The feasibility studies include evaluating the economical, social, and legal implications and policy frameworks to map out the entire project from the large-scale capture, transportation, and storage of CO2 using carbon capture and storage. The decision has yet to be made as to if the transportation of CO2 will occur by ship or pipeline to the storage facilities in developing Porthos and Aramis projects within Rotterdam in the Netherlands. Currently, 21 potential ship and pipeline transportation scenarios for use in the Carbon Connect Delta program have been mapped out.
The current status is focused on the development of the Porthos CO2 storage facilities and establishing port linkage between the ports of Rotterdam, Antwerp, and the North Sea Port as the area does not currently have the infrastructure (target 2024). Additionally, under the feasibility study environmental impacts and risk assessments are completed in the evaluation. Under the study, synergy opportunities and the mapping of various combinations of the project components, thus capture, transport, and storage of the CO2 which benefit the economy, project timeline, flexibility in project processing, project risk, and environmental feasibility. The aim is to have a well-established CO2 pipeline network between Antwerp and the North Sea Port area by 2026 to begin the mass-scale carbon sequestration, transportation, and storage in the established Porthos and Aramis storage projects. Once established the carbon sequestration initiative will travel further south to Ludwigshafen to aid Belgium and the Netherlands in their quest to achieve carbon neutrality by 2050.
References
Carbon capture and storage
Carbon dioxide removal
Climate change in Belgium
Climate change in the Netherlands | Carbon Connect Delta Program | [
"Engineering"
] | 2,975 | [
"Geoengineering",
"Carbon capture and storage"
] |
73,431,493 | https://en.wikipedia.org/wiki/Gold%28III%29%20phosphate | Gold(III) phosphate is a chemical compound with the formula AuPO4. It is a pale yellow solid that is insoluble in water and acetone. It decomposes at 450 °C into gold metal, phosphorus pentoxide, and oxygen.
Production
Gold(III) phosphate is produced by the reaction of gold(III) hydroxide and phosphoric acid at 130 °C:
AuO(OH) + H3PO4 → AuPO4 + 2H2O
It can also be produced by the replacement of phosphoric acid with a mixture of nitric acid and phosphorus pentoxide.
References
Gold(III) compounds
Phosphates | Gold(III) phosphate | [
"Chemistry"
] | 137 | [
"Salts",
"Phosphates",
"Inorganic compounds",
"Inorganic compound stubs"
] |
58,057,993 | https://en.wikipedia.org/wiki/Viviane%20Tabar | Viviane Tabar is an American neurosurgeon, the Chair of the Department of Neurosurgery at Memorial Sloan Kettering Cancer Center in New York since 2017.
Biography
Tabar took her medical degree from the American University of Beirut. It was followed by a neurosurgical residency at the University of Massachusetts. She did postdoctoral work at the National Institute of Neurological Disorders and Stroke.
Having done a research fellowship at Memorial Sloan Kettering Cancer Center, Tabar joined the faculty. At present, she is the Theresa C. Feng Chair for Neurosurgical Oncology and the Vice Chair for Neurosurgical Research and Education. In December 2017, she was named Chair of the Department of Neurosurgery at Memorial Sloan Kettering Cancer Center, succeeding to Philip Gutin, MD.
Viviane Tabar is also the founding Director of the Multidisciplinary Pituitary and Skull Base Tumor Center at Memorial Sloan Kettering Cancer Center.
Work
Tabar's specialty is intraoperative brain mapping techniques.
Her research is in stem cell biology, and she is one of the leaders of the New York State consortium for the development of human embryonic stem cell–derived dopamine neurons for Parkinson's disease. She has devised strategies for cell-based therapies for the repair of radiation-induced brain injury. Her lab has used pluripotent stem cells for brain tumor modeling, resulting in novel insights into the biology of gliomas and to the discovery of candidate therapeutic targets for brain tumors. She has a clinical expertise in the surgical management of brain tumors such as complex gliomas, meningiomas and skull base tumors. In 2010, with her research team of the Sloan-Kettering Cancer Center, she demonstrated the fact that tumorous blood vessel cells may come from tumor cells as a way to create their own blood supply. Those results contributed to demonstrate the great plasticity of tumors.
A prolific author, she has written dozens of widely cited publications.
Other roles
Since 2017: Member of the National Academy of Medicine
Since 2014: Member of the American Society for Clinical Investigation
Member of the Society of Neurological Surgeons
Member of the American Association of Neurological Surgery
Member of the American Brain Tumor Association
Friend of the Murray F. Brennan, MD, FACS, International Guest Scholarship Fund
Awards
2014: Top Doctors: New York Magazine
2013: Top Doctors: New York Metro Area
2012: Top Doctors: New York Metro Area
2011: Top Doctors: New York Metro Area
Publications
Personal life
Viviane Tabar is married to Lorenz Studer. They have two children together. They both work at the Sloan Kettering Institute heading medical research projects.
References
External links
Mentorship at Gerstner Sloan Kettering: Meet Ryan and Viviane
Living people
Memorial Sloan Kettering Cancer Center faculty
Year of birth missing (living people)
American neurosurgeons
American women physicians
American University of Beirut alumni
Place of birth missing (living people)
American neuroscientists
American women neuroscientists
Stem cell researchers
Members of the National Academy of Medicine
American women academics
21st-century American women | Viviane Tabar | [
"Biology"
] | 628 | [
"Stem cell researchers",
"Stem cell research"
] |
58,058,216 | https://en.wikipedia.org/wiki/Dimension%20of%20a%20scheme | In algebraic geometry, the dimension of a scheme is a generalization of a dimension of an algebraic variety. Scheme theory emphasizes the relative point of view and, accordingly, the relative dimension of a morphism of schemes is also important.
Definition
By definition, the dimension of a scheme X is the dimension of the underlying topological space: the supremum of the lengths ℓ of chains of irreducible closed subsets:
In particular, if is an affine scheme, then such chains correspond to chains of prime ideals (inclusion reversed) and so the dimension of X is precisely the Krull dimension of A.
If Y is an irreducible closed subset of a scheme X, then the codimension of Y in X is the supremum of the lengths ℓ of chains of irreducible closed subsets:
An irreducible subset of X is an irreducible component of X if and only if the codimension of it in X is zero. If is affine, then the codimension of Y in X is precisely the height of the prime ideal defining Y in X.
Examples
If a finite-dimensional vector space V over a field is viewed as a scheme over the field, then the dimension of the scheme V is the same as the vector-space dimension of V.
Let , k a field. Then it has dimension 2 (since it contains the hyperplane as an irreducible component). If x is a closed point of X, then is 2 if x lies in H and is 1 if it is in . Thus, for closed points x can vary.
Let be an algebraic pre-variety; i.e., an integral scheme of finite type over a field . Then the dimension of is the transcendence degree of the function field of over . Also, if is a nonempty open subset of , then .
Let R be a discrete valuation ring and the affine line over it. Let be the projection. consists of 2 points, corresponding to the maximal ideal and closed and the zero ideal and open. Then the fibers are closed and open, respectively. We note that has dimension one, while has dimension and is dense in . Thus, the dimension of the closure of an open subset can be strictly bigger than that of the open set.
Continuing the same example, let be the maximal ideal of R and a generator. We note that has height-two and height-one maximal ideals; namely, and the kernel of . The first ideal is maximal since the field of fractions of R. Also, has height one by Krull's principal ideal theorem and has height two since . Consequently,
while X is irreducible.
Equidimensional scheme
An equidimensional scheme (or, pure dimensional scheme) is a scheme all of whose irreducible components are of the same dimension (implicitly assuming the dimensions are all well-defined).
Examples
All irreducible schemes are equidimensional.
In affine space, the union of a line and a point not on the line is not equidimensional. In general, if two closed subschemes of some scheme, neither containing the other, have unequal dimensions, then their union is not equidimensional.
If a scheme is smooth (for instance, étale) over Spec k for some field k, then every connected component (which is then in fact an irreducible component), is equidimensional.
Relative dimension
Let be a morphism locally of finite type between two schemes and . The relative dimension of at a point is the dimension of the fiber . If all the nonempty fibers are purely of the same dimension , then one says that is of relative dimension .
See also
Kleiman's theorem
Glossary of scheme theory
Equidimensional ring
Notes
References
External links
Algebraic geometry | Dimension of a scheme | [
"Mathematics"
] | 790 | [
"Fields of abstract algebra",
"Algebraic geometry"
] |
58,058,550 | https://en.wikipedia.org/wiki/Rashmila%20Shakya | Rashmila Shakya (born 1980) is a Nepalese writer, software engineer, and Programme Director for Child Workers in Nepal. She authored the autobiography From Goddess to Mortal: the True Life Story of a Former Royal Kumari, which documents her time as Royal Kumari of Kathmandu.
Biography
She was recognized as the living reincarnation of the goddess Taleju when she was four years old. She served as the Royal Kumari from 1984 until 1991. She wrote the autobiography to change perceptions about the Kumari and raise awareness about the experiences of young girls who are chosen as the living Hindu goddesses. In her book she critiques the lack of education received by Kumaris and describes the challenges they face when returning to school and society after their time as Kumari has ended.
On 2 October 2015, Shakya, along with former Kumaris Nanimaiya Shakya, Sunina Shakya, Anita Shakya, Amita Shakya and Priti Shakya, was given money and acknowledgments for her contributions to culture and religion by Rudra Singh Tamang, the chief executive officer of Kathmandu Metropolitan City. Although criticizing the conditions and lack of education for Kumari, Shakya has not made an opinion as to whether the custom of Kumaris should continue, but believes it is culturally important. Shakya is married, despite the superstitions surrounding Kumari and marriage.
References
1980 births
Living people
Nepalese engineers
Software engineers
21st-century Nepalese writers
21st-century Nepalese women writers
Kumaris (goddesses) | Rashmila Shakya | [
"Engineering"
] | 312 | [
"Software engineering",
"Software engineers"
] |
58,059,699 | https://en.wikipedia.org/wiki/Offshore%20transmission%20owner | Offshore Transmission Owners (OFTOs) operate and maintain offshore electric power transmission infrastructure in Great Britain, delivering electrical power from offshore wind farms to the National Grid. OFTOs may design and build this transmission infrastructure, but in most cases wind farm developers construct the electrical transmission assets and then sell them to an OFTO once complete.
Operation
In the British electricity market, different functions of the electricity system are separated, with this practice beginning in the 1980s. The activities of generators, transmission operators, system operators, distribution operators and suppliers are separately licensed by Ofgem, with a single business unable to perform multiple functions due to UK Competition Law.
The groundwork for the offshore transmission regime was laid by the Energy Act 2004, with the first offshore transmission license being awarded in 2011. , all the offshore transmission infrastructure in Great Britain has been built by wind farm developers, who are then required to sell their transmission assets to a separately licensed Offshore Transmission Owner. The divestment must take place before the Generator Commissioning Clause date, on which the exemption from this requirement lapses.
Divestment is managed via a regulated tender process administered by the energy regulator Ofgem. Qualifying bidders are required to conduct due diligence before submitting a bid to purchase the assets for transfer value determined by Ofgem and receive their bid Tender Revenue Stream (TRS) for a fixed license period. Ofgem then appoints a Preferred Bidder who negotiates the purchase terms with the Developer, after which Ofgem awards a transmission license and the transfer takes place.
Offshore transmission operators
References
External links
Offshore Transmission (OFTO) regime, now fully in place, set to achieve further savings
https://www.4coffshore.com/news/race-bank-ofto-merger-approval-nid11189.html
https://www.spglobal.com/platts/en/market-insights/latest-news/electric-power/041219-five-bidders-shortlisted-for-uk-offshore-transmission-assets
https://www.offshorewind.biz/2019/04/12/five-remain-in-gbp-2-7-billion-ofto-race-in-uk/
Energy companies | Offshore transmission owner | [
"Engineering"
] | 463 | [
"Energy companies",
"Energy organizations"
] |
58,060,333 | https://en.wikipedia.org/wiki/Marwencol%20%28art%20installation%29 | Marwencol is a miniature town in Kingston, New York created by the American artist Mark Hogancamp.
On April 8, 2000, Mark Hogancamp was attacked outside of a bar by five men who beat him nearly to death after he drunkenly told them he was a cross-dresser. After nine days in a coma and 40 days in the hospital, Hogancamp was discharged with brain damage that left him little memory of his previous life. Unable to afford therapy, he created his own memory by building a -scale World War II-era Belgian town in his yard and populating it with dolls representing himself, his friends, and even his attackers. He called the town "Marwencol", blending his own name with that of a local bartender Wendy and his neighbor Colleen.
Hogancamp was initially discovered by photographer David Naugle, who documented and shared his story with Esopus magazine, whereby his work was shown in White Columns art gallery.
In media
The film Marwencol (also known as Village of the Dolls in the UK) is a 2010 American documentary film that explores Hogancamp's life and work. It is the debut feature of director-editor Jeff Malmberg. It was the inspiration for Welcome to Marwen, a 2018 drama directed by Robert Zemeckis and starring Steve Carell as Hogancamp.
Welcome to Marwencol is a 2015 art book by Hogancamp and Chris Shellen, published by Princeton Architectural Press, that documents Hogancamp's life and work. It was named one of the best books of 2015 by Amazon.com.
References
External links
Ronson, Jon (October 28, 2015). "Marwencol: the incredible WWII art project created by a cross-dresser who was beaten up by bigots". The Guardian.
Daily Freeman (May 29, 2000). "Another arrested in bar assault" Daily Freeman.
Times Herald-Record (April 11, 2000) "2nd man held in assault that left victim in coma" Times Herald-Record.
Action figures
Barbie
Kingston, New York
Miniature parks
Outsider art
Scale modeling
Works about Belgium
World War II in popular culture | Marwencol (art installation) | [
"Physics"
] | 428 | [
"Scale modeling"
] |
58,062,516 | https://en.wikipedia.org/wiki/Paul-Peter%20Tak | Paul-Peter Tak is a Dutch immunologist and academic specialising in the fields of internal medicine, rheumatology and immunology. Tak has been the President & CEO of Candel Therapeutics since September 2020.
Life and career
Tak graduated with a medical degree cum laude from the Amsterdam University Medical Centers and began his medical career as a practitioner in the Bronovo Hospital, The Hague. He joined Leiden University Medical Centre as a Fellow in Internal Medicine in 1990 and was awarded a Fellowship in Rheumatology in 1995. Tak received his PhD from Leiden University in 1996 for his thesis Immunohistologic studies of rheumatoid synovial tissue. He worked as a Clinical Associate Professor of Medicine at the University of California, San Diego, and next served as Professor of Medicine and Chair of the Department of Clinical Immunology & Rheumatology at Amsterdam UMC.
Tak has studied the role of the vagus nerve in chronic inflammation, work which provided the basis for clinical trials exploring bioelectronics as a novel therapeutic approach in rheumatoid arthritis patients. He is also known for his studies on synovial biopsy and synovial tissue analysis. In his academic life, Tak has been Visiting Professor, William Harvey Research Institute (London), Honorary Senior Visiting Fellow (University of Cambridge), Honorary Professor of Rheumatology (Ghent University) and was elected a Fellow of the Academy of Medical Sciences (U.K.) in 2016.
He was elected by peers as "Best Rheumatologist" in the Netherlands in 2011, and received the Medal of Honour of the Netherlands Society for Rheumatology the same year. He was rated as one of the world’s top 3 doctors in the field of rheumatoid arthritis by Expertscape in 2014.
From 2011 to 2018, Tak worked at GlaxoSmithKline as Senior Vice President, Chief Immunology Officer and Global Development Leader. He was also the Chair of the Scientific Review Board. In 2018, Tak cofounded Sitryx Therapeutics with researchers Houman Ashrafian, Luke O'Neill, Jonathan Powell, Jeff Rathmell, Michael Rosenblum. Tak was appointed as Board Director of Levicept in July 2018. Tak was chief executive at Tempero Pharmaceutical, which was acquired by GlaxoSmithKline, then served as Chief Executive Officer at Kintai Therapeutics in 2018. He was also a venture partner at Flagship Pioneering. In September 2020, Tak became president and CEO of Candel Therapeutics and, in July of the following year, led the company to an Initial Public Offering (IPO) on the Nasdaq. In 2021, Tak was named as one of the most inspiring people in life sciences on the PharmaVOICE100 list. Tak was included in The Medicine Maker Power List 2023 as one of the top ten leaders in the Biopharmaceuticals category. In March 2023, Tak was appointed Chair of the Board of Directors at Citryll.
Publications
Tak has an h-index of 144 according to Google Scholar. His publications include:
References
Year of birth missing (living people)
Living people
Vrije Universiteit Amsterdam alumni
Leiden University alumni
Biotechnologists
Dutch immunologists
Fellows of the Academy of Medical Sciences (United Kingdom) | Paul-Peter Tak | [
"Biology"
] | 683 | [
"Biotechnologists"
] |
58,062,999 | https://en.wikipedia.org/wiki/Amenamevir | Amenamevir (trade name Amenalief) is an antiviral drug used for the treatment of shingles (herpes zoster).
It acts as an inhibitor of the zoster virus's helicase–primase complex. Amenamevir was approved in Japan for the treatment of shingles in 2017.
See also
Pritelivir
References
Antiviral drugs
Oxadiazoles
Sulfones | Amenamevir | [
"Chemistry",
"Biology"
] | 91 | [
"Antiviral drugs",
"Sulfones",
"Biocides",
"Functional groups"
] |
58,065,470 | https://en.wikipedia.org/wiki/Rama%20Cont | Rama Cont is the Statutory Professor of Mathematical Finance at the
University of Oxford.
He is known for contributions to probability theory, stochastic analysis and mathematical modelling in finance, in particular mathematical models of systemic risk.
He was awarded the Louis Bachelier Prize by the French Academy of Sciences in 2010.
Biography
Born in Tehran (Iran), Cont obtained his undergraduate degree from Ecole Polytechnique (France), a master's degree in theoretical physics from Ecole Normale Superieure and a degree in Chinese Language from Institut national des langues et civilisations orientales. His doctoral thesis focused on the application of Lévy processes in financial modelling.
Career and achievements
Cont started his career as a CNRS researcher in applied mathematics at Ecole Polytechnique (France) in 1998 and held academic positions at Ecole Polytechnique, Columbia University and Imperial College London. He was appointed 'Directeur de Recherche CNRS' (CNRS Senior Research Scientist) in 2008 and was chair of mathematical finance at Imperial College London from 2012 to 2018. He was elected Statutory Professor in Mathematical Finance at the Oxford Mathematical Institute and professorial fellow of St Hugh's College, Oxford in 2018.
Cont's research focuses on probability theory, stochastic analysis and mathematical modelling in finance.
His mathematical work focuses on pathwise methods in stochastic analysis and the Functional Ito calculus.
In quantitative finance he is known in particular for his work on models based on jump processes, the stochastic modelling of limit order books as queueing systems
, machine learning methods in finance
and the mathematical modelling of systemic risk.
He was editor in chief of the Encyclopedia of Quantitative Finance.
Cont has served as advisor to central banks and international organizations such as the International Monetary Fund and the Bank for International Settlements on stress testing and systemic risk monitoring. His work on network models, financial stability and central clearing has influenced central banks and regulators
.
He has given numerous media interviews
on issues related to systemic risk and financial regulation.
Scientific contributions
Causal functional calculus
Cont is known in mathematics for his the "Causal functional calculus", a calculus for non-anticipative, or "causal", functionals on the space of paths.
Cont and collaborators built on the seminal work of German mathematician Hans Föllmer
and Bruno Dupire to construct a calculus for non-anticipative functionals, which includes as a special case the so-called Ito-Föllmer calculus, a pathwise counterpart of Ito's stochastic calculus.
Subsequent work by Cont and Nicolas Perkowski
extended
the Ito-Föllmer calculus to functions and functionals of more general irregular paths with non-zero p-th order variation.
Systemic risk modeling
Work by Cont and his collaborators on mathematical modeling of systemic risk and financial stability, in particular on network models of financial contagion and the modeling of indirect contagion via 'fire sales', has influenced academic research and policy in this area.
Central clearing
Cont's research on central clearing in over-the-counter (OTC) markets has influenced risk management practices of central counterparties and regulatory thinking on central clearing. Cont has argued that central clearing does not eliminate counterparty risk but transforms it into liquidity risk, therefore risk management and stress testing of central counterparties should focus on liquidity risk and liquidity resources, not capital.
Risk measurement and Model risk
Cont introduced a rigorous approach for the assessment of model risk
which has been influential in the design of model risk management frameworks in financial institutions.
Cont, Deguest and Scandolo introduced the concept of 'risk measurement procedure', an empirical counterpart of the notion of risk measure, and defined a robust class of risk measurement procedures known as 'Range Value-at-risk' (RVaR), a robust alternative to Expected shortfall.
Cont, Kotlicki and Valderrama define the concept of Liquidity at risk, as the amount of liquid assets needed by a financial institution to face liquidity outflows in this scenario.
Awards and honours
Cont was awarded the Louis Bachelier Prize by the French Academy of Sciences in 2010 for his work on mathematical modelling of financial markets.
He was elected Fellow of the Society for Industrial and Applied Mathematics (SIAM) in 2017 for "contributions to stochastic analysis and mathematical finance".
He received the Award for Excellence in Interdisciplinary Research (APEX) from the Royal Society in 2017 for his research on mathematical modelling of systemic risk.
Publications
Alt URL
References
External links
Professional Homepage
1972 births
Living people
École Polytechnique alumni
21st-century Iranian mathematicians
Applied mathematicians
Probability theorists
Fellows of St Hugh's College, Oxford
Fellows of the Society for Industrial and Applied Mathematics
Academics of the University of Oxford
Statutory Professors of the University of Oxford
Columbia University faculty | Rama Cont | [
"Mathematics"
] | 977 | [
"Applied mathematics",
"Applied mathematicians"
] |
58,065,766 | https://en.wikipedia.org/wiki/Robert%20Thunell | Robert Carl Thunell (February 16, 1951 – July 30, 2018) was an American oceanographer.
Born in Queens, New York City, on February 16, 1951, to parents Carl and Betty Hornbacher Thunell, Robert Thunell attended Brown University, where he played lacrosse and earned a bachelor's degree in geology/biology. Thunell pursued graduate study in oceanography at the University of Rhode Island. Upon earning his doctorate, Thunell became a postdoctoral fellow at Woods Hole Oceanographic Institution, after which he joined the University of South Carolina faculty in 1979. Thunell was named a fellow of the Geological Society of America in 1987. That same year, he also became a full professor. Five years later, Thunell was appointed a Carolina Distinguished Professor. He was granted fellowship by the American Geophysical Union and American Association for the Advancement of Science, in 2006 and 2010, respectively.
References
1951 births
2018 deaths
Scientists from Queens, New York
Scientists from New York City
American oceanographers
Fellows of the American Geophysical Union
Fellows of the American Association for the Advancement of Science
University of Rhode Island alumni
University of South Carolina faculty
Brown Bears men's lacrosse players
Biogeochemists
Fellows of the Geological Society of America
Brown University faculty | Robert Thunell | [
"Chemistry"
] | 258 | [
"Geochemists",
"Biogeochemistry",
"Biogeochemists"
] |
58,066,586 | https://en.wikipedia.org/wiki/EETAA%20722 | EETAA 722 is the French acronym for . It is a well known training school for mechanic apprentices of the French Air and Space Force. Its motto is "Honor, Work and Discipline".
Created in 1949 and located in Saintes, the school provides two years of demanding studies in Aviation and Aerospace.
Students are recruited from the tenth to 12th grade of high school through a national examination. Each year around 200 candidates are accepted and since 1999 it includes girls as well.
Students are aged from 16 to 18 and are nicknamed "s”. They follow a rigorous training program for either the Baccalaureate or the certificate of professional aptitude (CAP, level V in National classification of levels of training (1969)).
The streams of study offered are:
Baccalaureate in Sciences, option Engineering (SI)
Technological Baccalaureate STI.2D - SIN (Science and Technology of Industry and Sustainable Development, specialty Information Systems and Digital).
Baccalaureate in Aeronautics, specialty MSC (cell system mechanic);
Certificate of Professional Aptitude "Aircraft Systems Electrician".
Upon graduation most students are admitted to Air Base 721 the next school in Rochefort for non-commissioned officers (NCOs) where they receive further specialized advanced technical training.
Some graduates of the sciences stream with option engineering may attend a preparatory class for the French Air Force Academy.
References
Military training establishments of France
Military units and formations established in 1949
Military units and formations of the French Air and Space Force
Saintes, Charente-Maritime
Secondary schools in France
1949 establishments in France
Educational institutions established in 1949
Aircraft maintenance
Aviation schools in France
Training establishments of the French Air and Space Force | EETAA 722 | [
"Engineering"
] | 326 | [
"Aircraft maintenance",
"Aerospace engineering"
] |
58,067,684 | https://en.wikipedia.org/wiki/Geoffrey%20J.%20Gordon | Geoffrey J. Gordon is a professor at the Machine Learning Department at Carnegie Mellon University in Pittsburgh and director of research at the Microsoft Montréal lab. He is known for his research in statistical relational learning (a subdiscipline of artificial intelligence and machine learning) and on anytime dynamic variants of the A* search algorithm. His research interests include multi-agent planning, reinforcement learning, decision-theoretic planning, statistical models of difficult data (e.g. maps, video, text), computational learning theory, and game theory.
Gordon received a B.A. in computer science from Cornell University in 1991, and a PhD at Carnegie Mellon in 1999.
References
Carnegie Mellon University alumni
Carnegie Mellon University faculty
Cornell University alumni
Year of birth missing (living people)
Microsoft employees
Machine learning researchers
Living people | Geoffrey J. Gordon | [
"Technology"
] | 162 | [
"Computing stubs",
"Computer specialist stubs"
] |
58,068,464 | https://en.wikipedia.org/wiki/Cortical%20thymic%20epithelial%20cells | Cortical thymic epithelial cells (cTECs) form unique parenchyma cell population of the thymus which critically contribute to the development of T cells.
Thymus tissue is compartmentalized into cortex and medulla and each of these two compartments comprises its specific thymic epithelial cell subset. cTECs reside in the outer part- cortex, which mostly serves as a developmental site for T cells. Precursors of T cells originate in the bone marrow from which they migrate via bloodstream into thymic cortex, where they encounter stromal cells including cTECs, which form the microenvironment crucial for proliferation and development of T cells by expression of DLL4 (delta-like notch ligand 4), cytokines IL-7, TGFβ or stem cell factor and chemokines CCL25, CXCL12 or CCRL1 etc. Essential part of T cell development forms process called VDJ recombination, mediated by RAG recombinases, that stochastically changes DNA sequences of T cell receptors (TCR) and endows them with diverse recognition specificity. Thanks to this process, T cells can recognize vast repertoire of pathogens, but also self-peptides or even their TCRs don't respond to any surrounding signals. Major role of thymic epithelial cells is to test, whether TCRs are "functional" and on the other hand "harmless" to our body. While cTECs control the functionality of TCRs during the process called positive selection, Medullary thymic epithelial cells (mTECs) that home in the inner part of the thymus- medulla, present on their MHC molecules self-peptides, generated mostly by protein Autoimmune regulator, to eliminate T cells with self-reactive TCRs via processes of central tolerance e.g. negative selection and protect the body against development of autoimmunity.
Positive selection of T cells
Major function of cTECs is to positively select those T cells that are capable to recognize and interact with MHC molecules on their surface . Once T cell precursors enter the thymic cortex, they start their transformation from double negative stages (T cell without surface expression of CD4 and CD8 co-receptors) to a double positive stage (T cell with surface expression of both co-receptors) that expresses fully recombined TCR. This stage undergoes above mentioned selection process.
Double positive–single positive transition
Interaction between TCR of double positive T cell and MHC I molecule leads to loss of CD4 expression and double positive T cell becomes CD8 single positive T cell, conversely, engagement of MHC II molecule leads to the development into CD4 single positive T cell. It was also described that CD8/CD4 restriction is influenced by transcription factors Runx3, in the case of CD8 restriction, and Th-POK which directs the development into CD4 T cell lineage and represses the expression of Runx3. More than 90% of double positive T cells are unable to reach this interaction and they die by neglect.
Cortex–medulla migration
Besides double positive-single positive transition, TCR-MHC interaction also triggers the expression of CCR7, chemokine receptor which recognizes chemokines CCL19 and CCL21, that are largely produced by mTECs in the medulla, and positively selected T cells start to migrate to medulla via their gradient.
Unique proteolytic pathways
It is incompletely understood whether presence of peptide ligands on MHC molecules of cTECs plays some role in positive selection. But it is likely that these peptide-MHC complexes are unique and different from self-peptides presented by mTECs, since cTECs developed unique proteolytic pathways. Indeed, there is slight evidence focused on unique cTEC peptide ligands, nevertheless, its more systematic characterization is still required.
Thymoproteasome (β5t)
Enzymatic machinery for MHC I antigen processing and presentation in cTECs involves thymoproteasome, which is defined by the presence of β5t subunit encoded by Psmb11 gene. Knockout of this gene revealed only slight reduction in positive selection of CD8 T cells, but TCR repertoire of these cells was shown to be limited and they revealed impaired immunological properties e.g. bad antigen responsiveness and failure to maintain naive population in the periphery. β5t subunit was shown to reduce chymotrypsin-like activity of thymoproteasomes, resulting in generation of low affinity peptides. Such finding was confirmed by study that was focused on properties of thymoproteasome- chopped peptides. Importantly, low affinity interactions are considered to result in positive selection, whereas high affinity interactions are typical for negative selection and interaction with mTECs.
Cathepsin L
MHC II processing and presentation in cTECs took advantage of several proteolytic pathways including cathepsin L, encoded by Ctsl gene. Cathepsin S which is produced by most of the antigen- presenting cells along with mTECs is absent in cTECs. Cathepsin L not only cleaves invariant chain as other cathepsins, nevertheless was shown to cleave peptides for MHC II presentation and enlarge the pool of cTEC unique peptide ligands. Ctsl knockout mouse revealed severe reduction in frequency and repertoire of CD4 T cells and impairment of invariant chain degradation. Another study revealed that reduction of T cell repertoire wasn't caused by absence of invariant chain degradation, rather due to alterations in repertoire of cathepsin L cleaved peptides.
Thymus specific serine protease
Thymus specific serine protease is another cTEC specific enzyme, encoded by Prss16 gene, which is also involved in MHC II peptide processing. Prss16 knockout mice revealed reduced repertoire of positively selected CD4 T cells.
Macroautophagy
Common feature of cTECs and mTECs is constitutive macroautophagy. This process involves engulfment of portion of cytoplasm that contains organelles and vesicles into autophagosome that fuses with late endosomes or lysosomes and its content is chopped to small peptides. cTECs and mTECs utilize this endogenous pathway for MHC II presentation during selection processes, instead of common loading of exogenous peptides. Mouse with deficient macroautophagy, specifically in the thymus, revealed reduced numbers and repertoire of CD4 T cells.
Development
cTECs and mTECs originate from endoderm, more specifically from the third pharyngeal pouch and it has been shown that they share common progenitor cell. Importantly, mTECs during their development possess classical markers of cTECs including CD205 and β5t which are completely absent in mature mTECs, suggesting another possible cTEC function, namely they might serve as a progenitor cell reservoir for mTECs. Indeed, several lineage tracing studies confirmed that cTEC progenitors or even mature cTECs are capable to give rise to mTECs.
Nevertheless, there is available series of publications which suggests different mTEC progenitor pools or even argue that cTECs and mTECs reveal distinct unipotent progenitor cells.
References
Immunology
Thymus
Epithelial cells | Cortical thymic epithelial cells | [
"Biology"
] | 1,539 | [
"Immunology"
] |
58,069,185 | https://en.wikipedia.org/wiki/Condoliase | Condoliase (Hernicore) is a biopharmaceutical for the treatment of lumbar disc herniation. Clinical trials have shown its benefit in alleviation of lumbar disc herniation associated low back pain and disability, although some concerns have been suggested with regard to promotion of disc degeneration.
Condoliase is derived from the enzyme mucopolysaccharidase from the Gram-negative bacteria Proteus vulgaris. It functions as an enzymatic chemonucleolysis product, specifically designed to reduce the size of the protruded herniation. It is an enzyme that specifically degrades glycosaminoglycans.
It was approved for use in Japan in 2018 as a treatment for lumbar disc herniation.
References
Biopharmaceuticals | Condoliase | [
"Chemistry",
"Biology"
] | 175 | [
"Pharmacology",
"Biotechnology products",
"Biopharmaceuticals"
] |
58,069,454 | https://en.wikipedia.org/wiki/Evocalcet | Evocalcet (trade name Orkedia) is a drug for the treatment of hyperparathyroidism. It acts as a calcium-sensing receptor agonist.
In 2018, it was approved in Japan for treatment of secondary hyperparathyroidism in patients on dialysis.
References
Carboxylic acids
1-Naphthyl compounds
Pyrrolidines | Evocalcet | [
"Chemistry"
] | 77 | [
"Carboxylic acids",
"Functional groups"
] |
58,069,459 | https://en.wikipedia.org/wiki/C24H26N2O2 | {{DISPLAYTITLE:C24H26N2O2}}
The molecular formula C24H26N2O2 (molar mass: 374.47 g/mol, exact mass: 374.1994 u) may refer to:
Carmoxirole
Evocalcet
Furanylfentanyl
Molecular formulas | C24H26N2O2 | [
"Physics",
"Chemistry"
] | 73 | [
"Molecules",
"Set index articles on molecular formulas",
"Isomerism",
"Molecular formulas",
"Matter"
] |
66,143,991 | https://en.wikipedia.org/wiki/Cysteine%20methyl%20ester | Cysteine methyl ester is the organic compound with the formula HSCH2CH(NH2)CO2CH3. It is a white solid substance, known as the methyl ester of the amino acid, cysteine.
Uses
Under the brand name Mecysteine, cysteine methyl ester is a commercial drug for mucolytic activity. The compound has an ability to break down or lower the viscosity of mucin-containing secretions or components of fluids by chronic and acute respiratory disorders. The drug is sold under the commercial names Delta in Paraguay, and Pectite and Zeotin in Japan.
Cysteine methyl ester is also used as a building block for synthesis of N,S-heterocycles.
References
Expectorants
Amino acid derivatives
Methyl esters
Thiols
Sulfur amino acids | Cysteine methyl ester | [
"Chemistry"
] | 172 | [
"Organic compounds",
"Thiols"
] |
66,144,404 | https://en.wikipedia.org/wiki/%C5%9Einik%20%28unit%29 | Şinik was an Ottoman unit of volume.
The origin of the term Şinik is obscure. It may be a corrupt word from Uigur Turkish şing (which was loaned from Chinese) or Kypchack Turkish şunik. During the 14th century some of the Anatolian Beyliks used this unit for trade with the Byzantines. They defined the unit as being equivalent to Greek unit choenix which is equal to 1.08 liters. But during the Ottoman era it was equal to 9.25 liters. However, in 1881 the şinik was redefined to be 10 liters. In 1926 during the Turkish Republic the unit became obsolete.
References
Ottoman units of measurement
Units of volume | Şinik (unit) | [
"Mathematics"
] | 143 | [
"Units of volume",
"Quantity",
"Units of measurement"
] |
66,144,420 | https://en.wikipedia.org/wiki/Protist%20shell | Many protists have protective shells or tests, usually made from silica (glass) or calcium carbonate (chalk). Protists are a diverse group of eukaryote organisms that are not plants, animals, or fungi. They are typically microscopic unicellular organisms that live in water or moist environments.
Protists shells are often tough, mineralised forms that resist degradation, and can survive the death of the protist as a microfossil. Although protists are typically very small, they are ubiquitous. Their numbers are such that their shells play a huge part in the formation of ocean sediments and in the global cycling of elements and nutrients.
The role of protist shells depends on the type of protist. Protists such as diatoms and radiolaria have intricate, glass-like shells made of silica that are hard and protective, and serve as a barrier to prevent water loss. The shells have small pores that allow for gas exchange and nutrient uptake. Coccolithophores and foraminifera also have hard protective shells, but the shells are made of calcium carbonate. These shells can help with buoyancy, allowing the organisms to float in the water column and move around more easily.
In addition to protection and support, protist shells also serve scientists as a means of identification. By examining the characteristics of the shells, different species of protists can be identified and their ecology and evolution can be studied.
Protists
Cellular life likely originated as single-celled prokaryotes (including modern bacteria and archaea) and later evolved into more complex eukaryotes. Eukaryotes include organisms such as plants, animals, fungi and "protists". Protists are usually single-celled and microscopic. They can be heterotrophic, meaning they obtain nutrients by consuming other organisms, or autotrophic, meaning they produce their own food through photosynthesis or chemosynthesis, or mixotrophic, meaning they produce their own food through a mixture of those methods.
The term protist came into use historically to refer to a group of biologically similar organisms; however, modern research has shown it to be a paraphyletic group that does not contain all descendants of a common ancestor. As such it does not constitute a clade and is not currently in formal scientific use. Nonetheless, the term continues to be used informally to refer to those eukaryotes that cannot be classified as plants, fungi or animals.
Most protists are too small to be seen with the naked eye. They are highly diverse organisms currently organised into 18 phyla, but are not easy to classify. Studies have shown high protist diversity exists in oceans, deep sea-vents and river sediments, suggesting large numbers of eukaryotic microbial communities have yet to be discovered. As eukaryotes, protists possess within their cell at least one nucleus, as well as organelles such as mitochondria and Golgi bodies. Many protists are asexual but can reproduce rapidly through mitosis or by fragmentation; others (including foraminifera) may reproduce either sexually or asexually.
In contrast to the cells of bacteria and archaea, the cells of protists and other eukaryotes are highly organised. Plants, animals and fungi are usually multi-celled and are typically macroscopic. Most protists are single-celled and microscopic, but there are exceptions, and some marine protists are neither single-celled nor microscopic, such as seaweed.
Silicon-based shells
Although silicon is readily available in the form of silicates, very few organisms use it directly. Diatoms, radiolaria, and siliceous sponges use biogenic silica as a structural material for their skeletons. In more advanced plants, the silica phytoliths (opal phytoliths) are rigid microscopic bodies occurring in the cell; some plants, including rice, need silica for their growth. Silica has been shown to improve plant cell wall strength and structural integrity in some plants.
Diatoms
Diatoms form a (disputed) phylum containing about 100,000 recognised species of mainly unicellular algae. Diatoms generate about 20 per cent of the oxygen produced on the planet each year, take in over 6.7 billion metric tons of silicon each year from the waters in which they live, and contribute nearly half of the organic material found in the oceans.
Diatoms are enclosed in protective silica (glass) shells called frustules. The beautifully engineered and intricate structure of many of these frustules is such that they are often referred to as "jewels of the sea". Each frustule is made from two interlocking parts covered with tiny holes through which the diatom exchanges nutrients and wastes. The frustules of dead diatoms drift to the ocean floor where, over millions of years, they can build up as much as half a mile deep.
Diatoms uses silicon in the biogenic silica (BSiO2) form, which is taken up by the silicon transport protein to be predominantly used in constructing these protective cell wall structures. Silicon enters the ocean in a dissolved form such as silicic acid or silicate. Since diatoms are one of the main users of these forms of silicon, they contribute greatly to the concentration of silicon throughout the ocean. Silicon forms a nutrient-like profile in the ocean due to the diatom productivity in shallow depths, which means there is less concentration of silicon in the upper ocean and more concentration of silicon in the deep ocean.
Diatom productivity in the upper ocean contribute to the amount of silicon exported to the lower ocean. When diatom cells are lysed in the upper ocean, their nutrients like, iron, zinc, and silicon, are brought to the lower ocean through a process called marine snow. Marine snow involves the downward transfer of particulate organic matter by vertical mixing of dissolved organic matter. Availability of silicon appears crucial for diatom productivity, and as long as silicic acid is available for diatoms to utilize, the diatoms contribute other important nutrient concentrations in the deep ocean.
In coastal zones, diatoms serve as the major phytoplanktonic organisms and greatly contribute to biogenic silica production. In the open ocean, however, diatoms have a reduced role in global annual silica production. Diatoms in North Atlantic and North Pacific subtropical gyres contribute only about 6% of global annual marine silica production, while the Southern Ocean produces about one-third of the global marine biogenic silica. The Southern Ocean is referred to as having a "biogeochemical divide", since only minuscule amounts of silicon is transported out of this region.
Diatom frustules have been accumulating for over 100 million years, leaving rich deposits of nano and microstructured silicon oxide in the form of diatomaceous earth around the globe. The evolutionary causes for the generation of nano and microstructured silica by photosynthetic algae are not yet clear. However, in 2018 it was shown that absorption of ultraviolet light by nanostructured silica protects the DNA in the algal cells, and this may be an evolutionary cause for the formation of the glass cages.
Radiolarians
Radiolarians are unicellular predatory protists encased in elaborate globular shells (or "capsules"), usually made of silica and pierced with holes. Their name comes from the Latin for "radius". They catch prey by extending parts of their body through the holes. As with the silica frustules of diatoms, radiolarian shells can sink to the ocean floor when radiolarians die and become preserved as part of the ocean sediment. These remains, as microfossils, provide valuable information about past oceanic conditions.
Calcium-based shells
Coccolithophores
Coccolithophores are minute unicellular photosynthetic protists with two flagella for locomotion. Most of them are protected by a shell called a coccosphere. Coccospheres are covered with ornate circular plates or scales called coccoliths. The coccoliths are made from calcium carbonate. The term coccolithophore derives from the Greek for a seed carrying stone, referring to their small size and the coccolith stones they carry. Under the right conditions they bloom, like other phytoplankton, and can turn the ocean milky white.
There are benefits for protists that carry protective shells. The diagram on the left below shows some benefits coccolithophore get from carrying coccoliths. In the diagram, (A) represents accelerated photosynthesis including carbon concentrating mechanisms (CCM) and enhanced light uptake via scattering of scarce photons for deep-dwelling species. (B) represents protection from photodamage including sunshade protection from ultraviolet light (UV) and photosynthetic active radiation (PAR) and energy dissipation under high-light conditions. (C) represents armour protection includes protection against viral/bacterial infections and grazing by selective and nonselective grazers.
There are also costs for protists that carry protective shells. The diagram on the right above shows some of the energetic costs coccolithophore incur from carrying coccoliths. In the diagram, the energetic costs are reported in percentage of total photosynthetic budget. (A) represents transport processes include the transport into the cell from the surrounding seawater of primary calcification substrates Ca2+ and HCO3− (black arrows) and the removal of the end product H+ from the cell (gray arrow). The transport of Ca2+ through the cytoplasm to the coccolith vesicle (CV) is the dominant cost associated with calcification. (B) represents metabolic processes include the synthesis of coccolith-associated polysaccharides (CAPs – gray rectangles) by the Golgi complex (white rectangles) that regulate the nucleation and geometry of CaCO3 crystals. The completed coccolith (gray plate) is a complex structure of intricately arranged CAPs and CaCO3 crystals. (C) Mechanical and structural processes account for the secretion of the completed coccoliths that are transported from their original position adjacent to the nucleus to the cell periphery, where they are transferred to the surface of the cell.
Foraminiferans
Like radiolarians, foraminiferans (forams for short) are single-celled predatory protists, also protected with shells that have holes in them. Their name comes from the Latin for "hole bearers". Their shells, often called tests, may be single-chambered or multi-chambered; multi-chambered forams add more chambers as they grow. The most famous of these are made of calcite, but tests may also be made of aragonite, agglutinated sediment particles, chiton, or (rarely) of silica. Most forams are benthic, but about 40 living species are planktic. They are widely researched with well established fossil records which allow scientists to infer a lot about past environments and climates. Some foraminifera lack tests altogether.
Other shells
The cell body of many choanoflagellates is surrounded by a distinguishing extracellular matrix or periplast. These cell coverings vary greatly in structure and composition and are used by taxonomists for classification purposes. Many choanoflagellates build complex basket-shaped "houses", called lorica, from several silica strips cemented together. The functional significance of the periplast is unknown, but in sessile organisms, it is thought to aid attachment to the substrate. In planktonic organisms, there is speculation that the periplast increases drag, thereby counteracting the force generated by the flagellum and increasing feeding efficiency.
Microfossils and sediments
The shells or skeletons of many protists survive over geological time scales as microfossils. Microfossils are fossils that are generally between 0.001mm and 1 mm in size, the study of which requires the use of light or electron microscopy. Fossils which can be studied by the naked eye or low-powered magnification, such as a hand lens, are referred to as macrofossils.
Microfossils are a common feature of the geological record, from the Precambrian to the Holocene. They are most common in marine sediments, but also occur in brackish water, fresh water and terrestrial sedimentary deposits. While every kingdom of life is represented in the microfossil record, the most abundant forms are protist skeletons or cysts from the Chrysophyta, Pyrrhophyta, Sarcodina, acritarchs and chitinozoans, together with pollen and spores from the vascular plants.
In 2017, fossilized microorganisms, or microfossils, were discovered in hydrothermal vent precipitates in the Nuvvuagittuq Belt that may be as old as 4.28 billion years old, the oldest record of life on Earth, suggesting "an almost instantaneous emergence of life" (in a geological time-scale sense), after ocean formation 4.41 billion years ago, and not long after the formation of the Earth 4.54 billion years ago. Nonetheless, life may have started even earlier, at nearly 4.5 billion years ago, as claimed by some researchers.
See also
Cytoskeleton
Particulate inorganic matter
References
Further references
Xu, K., Hutchins, D. and Gao, K. (2018) "Coccolith arrangement follows Eulerian mathematics in the coccolithophore Emiliania huxleyi". PeerJ, 6: e4608. .
Protistan Skeletons: A Geologic History of Evolution and Constraint
Protista
Biomineralization
Skeletal system | Protist shell | [
"Chemistry",
"Biology"
] | 2,912 | [
"Eukaryotes",
"Protists",
"Bioinorganic chemistry",
"Biomineralization"
] |
66,144,538 | https://en.wikipedia.org/wiki/Games%2C%20Puzzles%2C%20and%20Computation | Games, Puzzles, and Computation is a book on game complexity, written by Robert Hearn and Erik Demaine, and published in 2009 by A K Peters. It is revised from Hearn's doctoral dissertation, which was supervised by Demaine. The Basic Library List Committee of the Mathematical Association of America has recommended it for inclusion in undergraduate mathematics libraries.
Topics
Games, Puzzles, and Computation concerns the computational complexity theory of solving logic puzzles and making optimal decisions in two-player and multi-player combinatorial games. Its focus is on games and puzzles that have seen real-world play, rather than ones that have been invented for a purely mathematical purpose. In this area it is common for puzzles and games such as sudoku, Rush Hour, reversi, and chess (in generalized forms with arbitrarily large boards) to be computationally difficult: sudoku is NP-complete, Rush Hour and reversi are PSPACE-complete, and chess is EXPTIME-complete. Beyond proving new results along these lines, the book aims to provide a unifying framework for proving such results, through the use of nondeterministic constraint logic, an abstract combinatorial problem that more closely resembles game play than the more classical problems previously used for completeness proofs.
It is divided into three parts. The first part concerns constraint logic, which involving assigning orientations to the edges of an undirected graph so that each vertex has incoming edges with large-enough total weight. The second part of this book applies constraint logic in new proofs of hardness of various real-world games and puzzles, by showing that, in each case, the vertices and edges of a constraint logic instance can be encoded by the moves and pieces of the game. Some of these hardness proofs simplify previously-known proofs; some ten of them are new, including the discovery that optimal play in certain multiplayer games can be an undecidable problem. A third part of the book provides a compendium of known hardness results in game complexity, updating a much shorter list of complete problems in game complexity from the 1979 book Computers and Intractability. An appendix provides a review of the methods from computational complexity theory needed in this study, for readers unfamiliar with this area.
Audience and reception
Although primarily a research monograph and reference work for researchers in this area, reviewer Oswin Aichholzer recommends the book more generally to anyone interested in the mathematics of games and their complexity. Liljana Babinkostova writes that Games, Puzzles, and Computation is enjoyable reading, successful in its "purpose of building a bridge between games and the theory of computation".
Leon Harkleroad is somewhat more critical, writing that the book feels padded in places, and Joseph O'Rourke complains that its organization, with many pages of abstract mathematics before reaching the real-world games, does not lend itself to cover-to-cover reading. However, both Harkleroad and O'Rourke agree that the book is well-produced and thought-provoking.
References
Mathematics books
2009 non-fiction books
Combinatorial game theory
Computational complexity theory | Games, Puzzles, and Computation | [
"Mathematics"
] | 641 | [
"Recreational mathematics",
"Game theory",
"Combinatorial game theory",
"Combinatorics"
] |
66,145,336 | https://en.wikipedia.org/wiki/Frederick%20Kenneth%20McTaggart | Frederick Kenneth McTaggart (30 November 1917 – 24 March 2004) was an Australian inorganic chemist who led pioneering research in microwave chemistry and gas plasma reactions – the production and use of ionised gas –and its applications in electronics, thermal coatings, treatment of polymers, and plasma metallurgy.
McTaggart invented and patented for the Commonwealth Scientific and Industrial Research Organisation means of incorporating heat-resistant properties in paint, and novel apparatuses for the production of metals from halides using plasma jets or microwaves, and published in the field.
Early life and education
Though his birth was not registered until 1918, Frederick Kenneth McTaggart (known as Ken) was born on 30 November 1917 at Elsternwick, to Victorian Railways industrial chemist Cyril (1881 – 1966), and teacher Hilda Theresa McTaggart (née Daniel, 1882 – 1966), and his sole sibling was an older sister, Jean.
Due to childhood illness his primary education started late; aged eight he entered Grade 4 at Ormond State School, then he was educated from age 13 at Melbourne Boys High School 1931–1936. He joined a school debating team, and the orchestra, of which he was leader in 1934, and was elected a prefect in 1935. He was a ham radio enthusiast, and in his 3rd year at the school was involved in the Wireless Club, of which he became vice-president, and built his own set, the 'MHS Twin', when in 1934 he was issued an Amateur Radio Licence,. It was an interest that he continued into adulthood and one he maintained throughout his life.
Aged 18 he commenced a Bachelor of Science in Chemistry at Melbourne University and in April 1939 was conferred Bachelor of Science in Wilson Hall, when he had already commenced a Master of Science with John Stuart Anderson working on the separation of hydrogen fluoride and zirconium for which he received 1st Class Honours in 1940. A Doctor of Science was conferred on him in 1965 by Melbourne University in recognition of his work on the chemistry of titanium and zirconium, and on reactions in low pressure discharges.
Early career
In November 1940 McTaggart worked at Carbide Works at Electrona in Tasmania until mid-1941, then returned to Melbourne to live at 4 Kenilworth Gve. Glen Iris.
C.S.I.R.
In 1942, on the recommendation of the Council for Scientific and Industrial Research (from 1949 Commonwealth Scientific and Industrial Research Organisation, or CSIRO), McTaggart was made its employee, working at first in facilities at Melbourne University then from later that year at Fishermans Bend when a new facility was opened there. His initial investigation was the chlorination of rutile found in Australian heavy beach sands which produced titanium tetrachloride; its importance in World War II then underway, was the dense white fume it produced on exposure to moist air, making it an effective smoke screen.
McTaggart's research in his position as Senior Principal Research Scientist headed a team including (in 1946) Ian Kraitzer, Chas Alsope, Margaret Ellis, Mick Bertrand and Joy Bear; and staff qualified in electronics; Keith Perger, appointed in 1962, replaced in 1968 by John A. Hamilton; and in glassblowing; in Port Melbourne Rudi Pillig transferred to the project from the Division of Chemical Physics, before which scientists including McTaggart and Newnham in the Minerals Utilization Section were themselves skilled glassblowers, and produced their own apparatus in glass or silica.
Tin
Given an increasing wartime shortage of tin, his team also commenced investigations into the production of titanium tetrachloride from local resources as an alternative material to replace stannic (tin) chloride in a number of applications. Previously prepared overseas by chlorinating titanium white pigment (titanium dioxide), McTaggart's work demonstrated that the potential expense of proposals to import titanium white could be avoided through development of his process in which rutile sand, briquetted with coal or charcoal, was chlorinated directly. At first operated on a pilot-plant scale with Australian rutile sand replacing titanium pigment, the process was adopted for large-scale manufacture.
Heat-resistant paint
Described as "one of the more imaginative members" of the Organisation, McTaggart continued mineral chlorination studies and early in 1944, Ian Kraitzer joined the research group in what was to become the Minerals Utilization Section of the future CSIR Division of Industrial Chemistry (created 1959), and then by a young recruit, Isabel Joy Bear as a Junior Laboratory Assistant, and later by Charles Alsope, together seeking new uses for titanium tetrachloride. In the alkoxides of titanium, in particular the properties of polymerised butyl titanate, they discovered an excellent vehicle for heat-resisting paint pigments; it was a use of titanium esters that was patented by CSIR, a project in which the Defence laboratories joined Kraitzer and McTaggart 's laboratory tests with paint formulation studies by Defence laboratories' George Winter (who later joined the Division of Mineral Chemistry). After McTaggart presented an account of their findings in Paris and London, industrial firms in England and the USA were soon marketing the new paint, and its heat-resistance was still attracting attention as late as 1962, though with no acknowledgment of the Australian contribution.
McTaggart and Jean Lehmann married in 1944. After the war in 1947 and during a period of residency in Europe and the USA he worked with H J Emeléus in the chemistry labs in Cambridge,
Europe
In 1947 the couple departed Australia on the Stratheden, and from September lived in Mt. Pleasant Rd., Cambridge while McTaggart worked with inorganic chemist Harry Julius Emeléus' laboratory in Downing Street. He resumed his amateur radio operation with callsign G3CUA. In 1948 he worked in Paris with Yvette Cauchois on a study concerning differences in the x-ray absorption of the elements zirconium and hafnium which they published in the Comptes Rendues of the French Academy of Science When the need arose to separate the two metals for use in atomic reactors, their basic study contributed to further CSIRO investigations to devise an effective method.
While in Europe McTaggart visited Brussels, Eindhoven, Oslo and Porsgrunn before spending three months from September in the US, then in January 1949 returned to Australia from Vancouver on the Aorangi, to continue work at CSIRO while living in Box Hill. Daughter Jennifer was born 8 August 1950 and in December McTaggart left CSIRO, sailing with his family on the Himalaya for employment in the UK with the British company, Laporte Industries in Luton where his work found commercial potential, and during which time he made further trips, by car, through Europe before rejoining CSIRO at the end of 1952.
Plasma investigations
During the 1950s McTaggart made an extensive investigation of the sulfides, selenides and tellurides (collectively known as chalcogenides) of titanium, zirconium, hafnium and thorium. The study synthesised and examined some fifty different compounds, collecting data on them which was published in Australian Journal of Chemistry in 1958, and investigated their preparation and the characteristics of their chemical, electrical and lubrication properties, resulting in a process for producing titanium sulfide-based dry lubricants for high temperatures which was patented.
Pioneering studies in microwave chemistry and gas plasma reactions led from this work into the electrical resistance and conduction of the sulphides, selenides, and tellurides, supported by his development of novel experimental apparatuses. Rather than use the glow discharge generated between two electrodes to produce a plasma reaction as Newnham and Watts had done, in the late 50s McTaggart drew on technology derived from the wartime electronics of radar capable of frequencies in the microwave region of the radio spectrum to create discharges without using electrodes. He induced the plasma with these charges into the gas through coils wound around the reaction vessel, thus avoiding contamination by metal from electrodes. In his monograph, McTaggart sums up the achievement: "Instead of an arc between electrodes, a radio-frequency field may be used to maintain the plasma."
This approach, using high frequency discharges led to the discovery of new chemical reactions in low pressure plasmas, verified by a mass spectrometer built in the Division to identify the active species involved in the reactions. Research continued along two main avenues; low pressure, athermal plasmas, with high electron energies producing neutral atoms, ions, etc., at ambient or low temperature, with applications in the areas of pure research, chemical analysis, surface preparation, and thin film production; and atmospheric or high pressure plasmas, previously achieved with electrodes producing a plasma 'jet' or 'torch', and used in parallel to McTaggart's microwave technique, for the production of high temperature, which best suited the interests of the Division in minerals.
International recognition
McTaggart spent four months in 1962 on a working tour through the US, Buenos Aires and England. In 1963 he assembled and presented his papers for an honorary doctorate, which was granted in 1965, during which year he again traveled in Europe and presented in Belgrade at the VIIth International Conference on Phenomena in Ionized Gases, and commenced his monograph on plasma chemistry which he completed the following year.
In April 1967, he was invited by the United States Air Force to the American Chemical Society Conference at Miami, Florida, then addressed the Institution of Mining and Metallurgy Conference in London. In September the English edition of his monograph was published.
On the basis of his work in plasma chemistry, during July and August 1971, McTaggart was sponsored for a tour of the United States by its Office of Naval Research, to be flown by the US Airforce to the NASA-Ames Base to participate in a seminar on plasma chemistry. In Washington D.C. he presented the inaugural lecture at the IUPAC (International Union of Pure and Applied Chemistry) Conference on Plasma Chemistry, which appointed him a member of its steering committee. Following that, he lectured at the Gordon Research Conference on Plasma Chemistry, held at Beaver Dam.
Late career
McTaggart transferred his research activities to the University of Sydney from November 1973 and retired in February 1978, after which he returned to Melbourne.
Patents
McTaggart's plasma research led to patents as assignor to the CSIRO, including US 3,533,777 Production of metals from their halides filed 2 Nov. 1966 for an apparatus and process for producing metals from the halides of metals of Groups I, II, III of the Periodic table and rare earth metals. It consisted of means to generate a plasma through high frequency electromagnetic energy within a gas or a vapor of that halide to cause the halide to dissociate, and then separating the metal thus produced from the other dissociation products, a process in which an auxiliary gas, hydrogen, helium or nitrogen, may also be used in conjunction with the halide.
He filed another patent on 5 Sept. 1967 for Plasma sintering with Neil Mckinnon, C.E.G. Bennet and Lloyd S. Williams, which was issued 11 March 1969.
Author
Aside from his oft-cited Plasma chemistry in electrical discharges published 1967 in 16 editions in 4 languages, McTaggart was author or co-author on a number of papers in journals including Australian Journal of Chemistry, Nature, and the Journal of Applied Chemistry on experimental research into its physics and chemistry and its applications.
Memberships
McTaggart was a member of the Society of Crystallographers in Australia (SCA).
Awards
For his work in applied chemical science on rutile sand, phosphate rock, graphite and beryl "which has contributed to the advancement of the welfare of the community", McTaggart was awarded the University of Melbourne's Grosvenor Laboratories Prize for 1946 by the Royal Australian Chemical Institute; and the Grimwade prize in industrial research for 1946 for his "Mineral Chlorination Studies.” He was among the first CSIRO officers to be awarded an honorary doctorate.
Personal life
McTaggart was named after his uncle, Frederick Daniel, who was at the time in the Mining Corp in France. His family moved to Ormond in about 1920 and Ken was home schooled by his mother, Hilda, a trained teacher. His late enrolment in primary school aged 8 was due to chronic bronchitis during his early childhood, but it gave way to robust health for the major part of his life.
With a keen interest in radio, McTaggart was granted his first Amateur Radio license in 1934 as VK3NW which remained his call sign, aside from during WW2 when no amateur radio transmission was allowed, and later during his period living in Sydney in the 1970s.
Ken was 13 when his mother arranged for him to attend Melbourne Boys High School arguing that his academic capacity warranted his admission, verified by his subsequent excellent academic achievements. He was made a prefect in his 2nd year of 6th Form, while preparing for admission to Melbourne University. He moved to Malvern for a brief period prior to employment in Tasmania.
When in 1941 McTaggart joined CSIRO and worked at both the Head Office and at Melbourne University, his family moved to Glen Iris. That year McTaggart played in the Melbourne Conservatorium Orchestra where he met Jean Lehmann to whom he was engaged the following year after her recovery from TB at Heatherton Sanatorium. McTaggart converted his first car to gas burning so that he could visit her there and journey to work at the Fisherman's Bend laboratories of CSIRO. They married in January 1944 and lived in Kew until 1947 when they travelled to Cambridge, UK, Paris and the USA. Regaining his radio license in 1946, in the UK he used the call sign G3CUA.
In early 1949, the couple returned to Australia after three months in the US and lived in Box Hill. Daughter Jennifer was born August 1950 and a few weeks later, the family moved to Luton, UK, where he was employed by Laporte. A number of trips to Europe, made this a busy time for the family, before a return to Australia late in 1952 when McTaggart was re-appointed to the Mineral Chemistry Division of CSIRO at Fisherman's Bend.
In 1953, the family bought their first home in Camberwell. In April 1954 son Stephen was born and in 1958 the family moved to a larger home in East Hawthorn. Over the next decade, McTaggart travelled extensively in the US, South America and the UK publishing prolifically, for which research he received an Honorary Doctorate in 1965, the year in which he travelled in Russia and France, and to Sweden where he was a member of the Australian archery team at the World Archery Championships, then the US, Canada, Japan and New Zealand. His interest in archery started in the early 1960s and he belonged to the Kew Archery club. This skill proved useful for his continuing interest in amateur radio as he made a special lead-weighted arrow that he could fire over tall trees to set up his aerials.
In 1970, Ken and Jean separated and he lived for a time in a St Kilda flat and in his shack at Woori Yallock before moving to Sydney and working at Sydney University in 1973. With longstanding friend Donald Westlake, principal Clarinet player in the Sydney Symphony Orchestra, he sailed from Sydney to Hobart in 1973, and later back to Sydney. He met his second wife, Betty Lewis, that year and they married in 1974, living in her home in Killara.
In 1975, McTaggart again travelled extensively overseas before retiring early in 1978. Later that year he separated from Betty and moved back to Box Hill in Melbourne. His granddaughter, Caitlyn, was born in July 1980 and McTaggart, being devoted to her, shared his time between Mount Gambier where she and her mother Jennifer lived, and Box Hill, living there with son Stephen, before moving to Mount Gambier on a more permanent basis in the early 1980s, then moved with Jennifer and Caitlyn to Hamilton in 1989, returning to live with Stephen in 1992 in Box Hill South. As he aged he lost little of his acumen, but became frail and lived in supported accommodation for several years before his death, 24 March 2004.
Introverted and thoughtful, McTaggart preferred a simple lifestyle that belied the complexity and depth of his achievements. A great reader, he loved the Brontës and belonged to the Brontë Society (UK) for much of his adult life, continued his love of radio, was a great lover of classical music and ballet to which he introduced granddaughter Caitlyn at an early age, and shared a love of border collies that his daughter owned and bred for some decades. He also enjoyed cricket, golf, archery and tennis, and was always happy in solitude, camping and fishing in the rivers of the Marysville area. He indulged in a wicked sense of humour with those who knew him well.
Publications
Book
Articles
McTaggart, F.K. Mineral chlorination studies. 1. Production of titanium tetrachloride from Australian rutile sand. Journal of the Council for Scientific and Industrial Research. 1945; 18(1):5-26. http://hdl.handle.net/102.100.100/338864?index=1
Kraitzer, I. McTaggartr, K. and Winter, G. (1948). Esters of Titanium. Journal of Oil and Colour Chemists Association, 31, 4 0 5 -17.
McTaggart, F.K. (1945). Mineral Chlorination Studies. 1. Production of Titanium Tetrachloride from Australian Rutile Sand. Journal of lhe Council for Scienlific and Industrial Research, 18(1), 5 -26.
McTaggart, F.K. (1945b). Mineral Chlorination Studies. 2. The Production of Phosphorus Oxychloride by Direct Chlorination of Phosphate Rock. Journal of the Council for Scientific and Industrial Research, 18(4), 424 -32.
McTaggart, F.K. (1947). Mineral Chlorination Studies. 3. The Chlorination of Australian Beryl. Journal of the Council for Scientific and Industrial Research, 20(4), 5 6 5-84
McTaggart, F.K. (1947). Mineral Chlorination Studies. 4. The Beneficiation of Australian Graphite by Treatment with Chlorine at High Temperatures. Journal of the Council for Scientific and Industrial Research, 20(3), 1 -10.
Cauchols Y. et McTaggart K. (1949) 'Doslmétrle par absorption dl!férentlelle des rayons X, à l'aide de spectromètres à cristaux courbés et de computeurs de Geiger.' Extrait des Comptes rendus des séances de l'Academie des Sciences, séance du 21 mars 1949. C.R. 228:1003
McTaggart, F.K. Systematic chemistry of the transition elements - recent chemistry of titanium, zirconium and hafnium. Reviews in Pure and Applied Chemistry. 1951. 152–170. http://hdl.handle.net/102.100.100/337739?index=1
McTaggart, F.K. and Newnham, I.E. (1951). The Use of Radioactive Tracers in the Separation of Hafnium and Zirconium. Conference on Applications of Isotopes in Scientific Research, Melbourne, 1950, 1 6 7 -74.
McTaggart, F.K. and Bear, J. (1955), Phototropic effects in oxides. I. Titanium dioxide. J. Appl. Chem., 5: 643–653. https://doi.org/10.1002/jctb.5010051203
McTaggart, F.K. (1956). Australian Patent 205,568
Bear, J., & McTaggart, F. K. (1958). Phototropic effects in oxides. II. White oxides in general. Journal of Applied Chemistry, 8(1), 72–76.
McTaggart, F. K., & Wadsley, A. D. (1958). The sulphides, selenides, and tellurides of titanium, zirconium, hafnium, and thorium. I. Preparation and characterization. Australian Journal of Chemistry, 11(4), 445–457.
McTaggart, F. K., & Moore, A. (1958). The sulphides, Selenides, and Tellurides of Titanium, Zirconium, Hafnium, and Thorium. IV. Lubrication properties of the graphitic chalcogenides. Australian Journal of Chemistry, 11(4), 481–484.
Blackwood, J. D., & McTaggart, F. K. (1959). Reactions of carbon with atomic gases. Australian Journal of Chemistry, 12(4), 533–542.
Blackwood, J.D. and, F.K. (1959b). A New Approach to Carbon Gasification. Nature, 184, 447–8.
Blackwood, J. D., & McTaggart, F. K. (1959). The oxidation of carbon with atomic oxygen. Australian Journal of Chemistry, 12(2), 114–121.
Graham, J., & McTaggart, F. K. (1960). Observations on the systems Th-S, Th-Se and Th-Te. Australian Journal of Chemistry, 13(1), 67–73.
McTaggart, F. K. (1961). Reduction of zirconium and hafnium Oxides. Nature, 191(4794), 1192-1192.
McTaggart FK, New proton-Containing Oxides of Titanium, Zirconium and Hafnium. Nature 199, 339–341 (1963). https://doi.org/10.1038/199339a0
McTaggart FK Turnbull AG (1964) Zirconium difluoride. Australian Journal of Chemistry 17, 727-730. https://doi.org/10.1071/CH9640727
McTaggart FK (1964) Reactions of carbon monoxide in a high-frequency discharge. Australian Journal of Chemistry 17, 1182–1187. https://doi.org/10.1071/CH9641182
McTaggart, F. K. (1964). Reduction of silica in a hydrogen discharge. Nature, 201(4926), 1320–1321.
McTaggart, F. K., & Turnbull, A. G. (1964). Zirconium difluoride. Australian Journal of Chemistry, 17(7), 727-730
McTaggart, F.K. (1965). Reduction of the Alkali and Alkaline Halides in High Frequency Discharges, Part I - Hydrogen Discharge; Part II - The Role of Electrons. Australian Journal of Chemistry, 18(7) 9 3 7-48; 9 4 9-57.
McTaggart F.K, Reduction of the Alkali and Alkaline Earth Halides by Active Hydrogen. Nature 206, 616 (1965). https://doi.org/10.1038/206616a0
Black, A. L., Dunster, R. W., Sanders, J. V., & McTaggart, F. K. (1967). Molybdenum bisulphide deposits—their formation and characteristics on automotive engine parts. Wear, 10(1), 17–32.
McTaggart, F. K. (1965). Reduction of the alkali and alkaline earth halides in high-frequency discharges. I. Hydrogen discharge. Australian Journal of Chemistry, 18(7), 937–948.
McTaggart, F.K. (1967). Formation of Metals from Their Halides by Plasma Reactions. Proceedings of the Symposium, Advances in Extractive Metallurgy (London). (Institution of Mining and Metallurgy: London.)
McTaggart, F.K. (1969). The Dissociation of Metal Halides in Electrical Discharges. In Chemical Reactions in Electrical Discharges. Advances in Chemistry Series No. 80, 176-81 (American Chemical Society: Eton, Pa.).
McIntyre, R.J. and McTaggart F.K. (1970). Comparison of the Reactions of Atomic and Molecular Halogens with Silver. Journal of Physical Chemistry, 74, 866–74.
Dorman, F. H., & McTaggart, F. K. (1970). Absorption of microwave power by plasmas. Journal of Microwave Power, 5(1), 4-16.
Chandler, B. V., & McTaggart, F. K. (1971). Fluorine atoms from an RF electric discharge. Australian Journal of Chemistry, 24(12), 2683–2684.
Dorman, F.H. and F.K. (1972). Electron Density and Temperature in Microwave Plasmas at Higher Pressures. Journal of Microwave Power, 7(3), 1 8 1 - 4
References
1917 births
2004 deaths
CSIRO people
Australian metallurgists
Australian mineralogists
Plasma physicists
20th-century Australian inventors
Inorganic chemists
Australian male archers
Amateur radio people
Scientists from Melbourne
20th-century Australian sportsmen | Frederick Kenneth McTaggart | [
"Physics",
"Chemistry"
] | 5,336 | [
"Plasma physicists",
"Inorganic chemists",
"Plasma physics"
] |
66,145,667 | https://en.wikipedia.org/wiki/Ware%20report | Security Controls for Computer Systems, commonly called the Ware report, is a 1970 text by Willis Ware that was foundational in the field of computer security.
Development
A defense contractor in St. Louis, Missouri, had bought an IBM mainframe computer, which it was using for classified work on a fighter aircraft. To provide additional income, the contractor asked the Department of Defense (DoD) for permission to sell computer time on the mainframe to local businesses via remote terminals, while the classified work continued.
At the time, the DoD did not have a policy to cover this. The DoD's Advanced Research Projects Agency (ARPA) asked Ware - a RAND employee - to chair a committee to examine and report on the feasibility of security controls for computer systems.
The committee's report was a classified document given in January 1970 to the Defense Science Board (DSB), which had taken over the project from ARPA. After declassification, the report was published by RAND in October 1979.
Influence
The IEEE Computer Society said the report was widely circulated, and the IEEE Annals of the History of Computing said that it, together with Ware's 1967 Spring Joint Computer Conference session, marked the start of the field of computer security.
The report influenced security certification standards and processes, especially in the banking and defense industries, where the report was instrumental in creating the Orange Book.
External links
References
Computer security
RAND Corporation | Ware report | [
"Technology"
] | 283 | [
"Computer security stubs",
"Computing stubs"
] |
66,146,272 | https://en.wikipedia.org/wiki/Elabela | ELABELA (ELA, Apela, Toddler) is a hormonal peptide that in humans is encoded by the APELA gene. Elabela is one of two endogenous ligands for the G-protein-coupled APLNR receptor.
Ela is secreted by certain cell types including human embryonic stem cells. It is widely expressed in various developing organs such as the blastocyst, placenta, heart, kidney, endothelium, and is circulating in human plasma.
Discovery
Elabela is a micropeptide that was identified in 2013 by Professor Bruno Reversade's team.
Biosynthesis
Elabela gene encodes a pre-proprotein of 54 amino acids, with a signal peptide in the N-terminal region. After translocation into the endoplasmic reticulum and cleavage of the signal peptide, the proprotein of 32 amino acids may generate several active fragments.
Physiological functions
The sites of APLNR receptor expression are linked to the different functions played by Elabela in the organism. Despite that, Elabela is capable of signaling independently of APLNR in human embryonic stem cells and certain cancer cell lines including OVISE.
Embryonic pluripotency
The Elabela protein is synthesized, processed and secreted by undifferentiated human embryonic stem cells but not mouse embryonic stem cells. In humans it is under the direct regulation of POU5F1 (a.k.a. OCT4) and NANOG.
Through autocrine and paracrine signalling, endogenous Elabela entrains the PI3K/AKT/mTOR pathway to maintain pluripotency and self-renewal.
Vascular
Elabela is expressed by midline tissues (such as the notochord in zebrafish and neural tube in mammals) during organogenesis.
There it serves as a chemoattractant to angioblasts expressing APLNR at their cell surface. This participates in the formation of the first and secondary vessels of the vascular system.
Cardiac
The ELABELA -APLNR signaling axis is required for formation of the coronary vessels of the heart in mice through the sinus venosus progenitors.
Pre-eclampsia
ELA is a secreted into the bloodstream by the developing placenta. Pregnant mice lacking Ela, exhibit pre-eclampsia-like symptoms, characterized by proteinuria and gestational hypertension.
Infusion of exogenous ELA normalizes blood pressure and prevents intrauterine growth retardation in pups born to Ela knockout mothers. ELA increases the invasiveness of trophoblast-like cells, suggesting that it may enhance placental development to prevent eclampsia.
Therapeutics
Several mimetics of ELA have been developed for therapeutic purposes. Amgen has created a camel antibody and a small molecule agonist capable of mimicking the function of ELA towards it cognate receptor APLNR.
The latter has entered phase 1 clinical trials for heart failure and acute kidney disease. Bristol Myers Squibb has also created its own small molecule agonist of APLNR.
An opinion published in the Lancet in 2019 suggested that ELABELA could be used to treat intrauterine growth restriction and maternal morbidity linked to eclampsia.
References
Genes
Peptides
Ligands
Hormones | Elabela | [
"Chemistry"
] | 705 | [
"Biomolecules by chemical classification",
"Ligands",
"Coordination chemistry",
"Molecular biology",
"Peptides"
] |
66,146,322 | https://en.wikipedia.org/wiki/Sheypoor | Sheypoor (; "bugle") is a classified ads platform website and mobile application, headquartered in Tehran, Iran. Thousands of advertisements are added to the app every day.
See also
Divar (website)
References
External links
Official website
Persian-language websites
E-commerce websites
Mobile software
Android (operating system) software
IOS software
Privately held companies of Iran
Online companies
Online marketplaces of Iran
Iranian companies established in 2013 | Sheypoor | [
"Technology"
] | 86 | [
"Mobile software stubs",
"Mobile technology stubs"
] |
66,146,568 | https://en.wikipedia.org/wiki/C24H39NO7 | {{DISPLAYTITLE:C24H39NO7}}
The molecular formula C24H39NO7 (molar mass: 453.576 g/mol, exact mass: 453.2727 u) may refer to:
Delcosine
Gigactonine
Vinervine
Molecular formulas | C24H39NO7 | [
"Physics",
"Chemistry"
] | 66 | [
"Molecules",
"Set index articles on molecular formulas",
"Isomerism",
"Molecular formulas",
"Matter"
] |
66,147,490 | https://en.wikipedia.org/wiki/Bound%20state%20in%20the%20continuum | A bound state in the continuum (BIC) is an eigenstate of some particular quantum system with the following properties:
Energy lies in the continuous spectrum of propagating modes of the surrounding space;
The state does not interact with any of the states of the continuum (it cannot emit and cannot be excited by any wave that came from the infinity);
Energy is real and Q factor is infinite, if there is no absorption in the system.
BICs are observed in electronic, photonic, acoustic systems, and are a general phenomenon exhibited by systems in which wave physics applies.
Bound states in the forbidden zone, where there are no finite solutions at infinity, are widely known (atoms, quantum dots, defects in semiconductors). For solutions in a continuum that are associated with this continuum, resonant states are known, which decay (lose energy) over time. They can be excited, for example, by an incident wave with the same energy. The bound states in the continuum have real energy eigenvalues and therefore do not interact with the states of the continuous spectrum and cannot decay.
Classification of BICs by mechanism of occurrence
Source:
BICs arising when solving the inverse problem
Wigner-von Neumann's BIC (Potential engineering)
The wave function of one of the continuum states is modified to be normalizable and the corresponding potential is selected for it.
Hopping rate engineering
In the tight binding approximation, the jump rates are modified so that the state becomes localized
Boundary shape engineering
Sources for BICs of different types, e.g. Fabry-Perot type are replaced by scatterers so as to create BIC of the same type.
BICs arising due to parameter tuning
Fabry-Perot BICs
For resonant structures, the reflection coefficient near resonance can reach unity. Two such structures can be arranged in such a way that they radiate in antiphase and compensate each other.
Friedrich-Wintgen BICs
Two modes of the same symmetry of one and the same structure approach each other when the parameters of the structure are changed, and at some point an anti-crossing occurs. In this case, BIC is formed on one of the branches, since the modes as if compensate each other, being in antiphase and radiating into the same radiation channel.
Single-resonance parametric BICs
Occur when a single mode can be represented as a sum of contributions, each of which varies with the structure parameters. At some point, destructive interference of all contributions occurs.
Symmetry-protected BICs
Arise when the symmetry of the eigenstate differs from any of the possible symmetries of propagating modes in the continuum.
Separable BICs
Arise when the eigenvalue problem is solved by the Separation of Variables Method, and the wave function is represented, for example, as , where both multipliers correspond to localized states, with the total energy lying in the continuum.
Wigner-Von Neumann BICs
Bound states in the continuum were first predicted in 1929 by Eugene Wigner and John von Neumann. Two potentials were described, in which BICs appear for two different reasons.
In this work, a spherically symmetric wave function is first chosen so as to be quadratically integrable over the entire space. Then a potential is chosen such that this wave function corresponds to zero energy.
The potential is spherically symmetric, then the wave equation will be written as follows:
the angle derivatives disappear, since we limit ourselves to considering only spherically symmetric wave functions:
For to be the eigenvalue for the spherically symmetric wave function , the potential must be
.
We obtain the specific values and for which the BIC will be observed.
First case
Let us consider the function . While the integral must be finite, then considering the behavior when , we get that , then considering the behavior when , we get . The regularity in requires . Finally, we get .
Assuming , then the potential will be equal to (discarding the irrelevant multiplier ):
The eigenfunction and the potential curve are shown in the figure. It seems that the electron will simply roll off the potential and the energy will belong to the solid spectrum, but there is a stationary orbit with .
In the work is given the following interpretation: this behavior can be understood from an analogy with classical mechanics (considerations belong to Leo Szilard). The motion of a material point in the potential is described by the following equation:
It's easy to see that when , , so the asymptotic is
that is, for a finite time the point goes to infinity. The stationary solution means that the point returns from infinity again, that it is as if it is reflected from there and starts oscillating. The fact that at tends to zero follows from the fact that it rolls down a large potential slide and has an enormous speed and therefore a short lifetime. And since the whole oscillatory process (from to infinity and back) is periodic, it is logical that this quantum mechanical problem has a stationary solution.
Second case
Let's move on to the second example, which can no longer be interpreted from such considerations.
First of all, we take a function , then . These are divergent spherical waves, since the energy is greater than the potential , the classical kinetic energy remains positive. The wave function belongs to a continuous spectrum, the integral diverges. Let's try to change the wave function so that the quadratic integral converges and the potential varies near -1.
Consider the following ansatz:
If the function is continuous, and at the asymptotic is then the integral is finite. The potential would then be equal (with the corrected arithmetical error in the original article):
In order for the potential to remain near -1, and at tend to -1, we must make the functions small and at tend to zero.
In the first case, also should vanish for , namely for , that is for . This is the case when or any other function of this expression.
Let assume , where is arbitrary (here tends to when ). Then
The expression for the potential is cumbersome, but the graphs show that for the potential tends to -1.
Furthermore, it turns out that for any one can choose such an A that the potential is between and .
We can see that the potential oscillates with period and the wave function oscillates with period . It turns out that all reflected waves from the "humps" of such a potential are in phase, and the function is localized in the center, being reflected from the potential by a mechanism similar to the reflection from a Bragg mirror.
Notes
Literature
Waves
Quantum optics | Bound state in the continuum | [
"Physics"
] | 1,361 | [
"Physical phenomena",
"Quantum optics",
"Quantum mechanics",
"Waves",
"Motion (physics)"
] |
66,148,395 | https://en.wikipedia.org/wiki/Allochronic%20speciation | Allochronic speciation (also known as allochronic isolation, or temporal isolation) is a form of speciation (specifically ecological speciation) arising from reproductive isolation that occurs due to a change in breeding time that reduces or eliminates gene flow between two populations of a species. The term allochrony is used to describe the general ecological phenomenon of the differences in phenology that arise between two or more species—speciation caused by allochrony is effectively allochronic speciation.
Environmental changes acting on a species population or populations can drive isolation. An important form of isolation is when populations are separated, not geographically, but temporally (by time). Genetic changes (mutations) over time can cause the two populations to differ—notably in phenology (events in a species life dictated by time such as breeding seasons); exhibiting unique phenotypes (the observable characteristics or traits of an organism).
Scientists have developed models to explain how this process occurs and how it is detected in natural populations. A wealth of studies exist regarding species in allochrony, with a select few that strongly suggest species are speciating or already have speciated as a direct consequence of this mode of isolation.
Model
Speciation ultimately results due to the reproductive isolation between two populations. This can happen in a multitude of ways, a common mode of which is known as allopatric speciation. The geographic mode, where two species become physically isolated and unable to interbreed, allows for selection to act on both populations independently. Over time, this gives rise to a new species. Allochronic speciation is a form of isolation that can involve allopatry; however, it is not required.
Allochrony can involve a number of factors that induce the formation of a new species. Organisms have evolved various reproductive strategies (e.g. semelparity and iteroparity, single or multiple reproductive cycles in a lifetime) that can result in different outcomes for allochrony. Many organisms also breed at different times of the day, different seasons in the year, and even over multiple years or decades. Seasonal breeding in animals is a common occurrence as well as spawning (in aquatic animals) times. In plants, breeding in regards to time could involve the receptivity of the stigma (the female part of the flower) to accepting sperm, periods of pollen release (such as in conifer trees where male cones disperse pollen relying on wind to direct pollen to female cones), or the overall timing of flowering (based on possible environmental cues such as moisture levels, soil type or quality, temperature, or photoperiod). Even migratory patterns can play a role, as species may become isolated due to migrating at different times and to different locations. Climate change is considered to have a significant impact on allochrony—in particular, seasonal breeding species. Modeling changes in species breeding patterns due to climate as well as understanding the genetic mechanisms that control it has proven to be important.
Because of these many factors, slight to major changes in phenology can drive divergence between two populations. For example, a species with multiple breeding seasons in a year may shift those times depending on external conditions such as temperature or predation. In the event the populations (either allopatrically or sympatrically distributed, started breeding at different times, it would prevent members of each population from exchanging genes with one another. Over time, if genes are not exchanged, genetic differences arise in each population. If natural selection acts strongly on the two populations, they may become reproductively isolated, unable to reproduce viable, fertile offspring.
For allochronic speciation to be considered to have actually occurred, the model necessitates three major requirements:
Phylogenetic analysis must indicate that the two taxa in question are incipient species or clearly sister taxa.
Breeding timing is required to be genetically-based (heritable) as opposed to changeable throughout life (phenotypic plasticity.
The source of divergence can be determined to be explicitly allochrony and not the result of reinforcement or other evolutionary mechanisms.
Allochrony is thought to evolve more easily the greater the heritability of reproductive timing—that is, the greater the link between genes and the timing of reproduction—the more likely speciation will occur. Allochrony can be non-genetic; however genetic factors must be involved for isolation to lead to complete reproductive isolation and subsequent speciation. The time frames involving allochrony are typically divided into three categories (prevalence in nature as well as examples are provided alongside each category):
Daily (considered to be common), examples include stony corals such as Acropora or Orbicella.
Seasonally (considered to be the most common), seasonal breeding times often coincide with winter, spring, fall, or summer; examples include salmon breeding runs such as in sockeye salmon.
Yearly (considered rarer), examples include periodical cicadas and bamboo, both of which reproduce within a scale of decades.
Population structures
Other phenotypic traits are often found to co-occur with reproductive timing such as flowering number, egg-clutch sizes, reproductive lifespans, or body size—what can be defined as temporal phenotypic clines. Two explanations exist for the existence of these clines: phenotypic plasticity or phenotypic heritability (or possibly a combination of both). If plastic, the clines arise when certain phenotypic traits influence breeding time—such as reproducing at times when their traits are best suited or if conditions drive the expression of traits. If heritable, the same factors may be expressed as they are in a plastic explanation; however, gene flow limitations allow for adaptation to the specific conditions of the reproductive time. This means that, "an individual with a heritable tendency to reproduce early that instead reproduced late might express traits typical of early reproducers".
Isolation by time (IBT) is partially analogous to the concept of isolation by distance (IBD) wherein genetic differences between populations increase with spatial distance. When IBT is present in a population, the variation of natural selection during a breeding season causes adaptation by time (ABT) generating adaptive temporal variation in phenotypic traits. These two concepts are described in the following sections. Studies of salmonid fishes (involving reproductive lifespans, size at adulthood, age, energy storage, the mass of ovaries, egg sizes, number of eggs in a clutch, fecundity, and rates of development) and flowering plants (involving plant size, duration of flowing time, the number of flowers, the number of fruits, the timing of fruiting, and leaf size) have provided strong evidence of IBT leading to ABT as well as studies of yearly allochrony.
Isolation by time
The concept of IBT warrants two probabilities: in the event that heritability in reproductive timing exists among populations that breed during different seasons, probability of mating will be, "inversely proportional to the difference in the heritable component of their reproductive times." The probability of mating can also be proportional to breeding values (phenotypic trait expressed as the trait of tis offspring) for reproductive time in the event the heritability is additive (more than one gene controls the phenotypic trait). In a population, offspring will inherit the traits for reproductive time causing a decrease in gene flow while reproductive timing differences increase.
Adaptation by time
Adaptation by time is an extension of divergence due to limited gene flow between populations experiencing different selective pressures. Typically this is limited to spatial variation such as in ecological speciation; however, in allochrony, selection varies not just in space, but in reproductive time—giving rise to adaptive temporal clines in phenotypic traits that are heritable. Isolation by time effectively allows adaptive temporal clines to evolve as long as the reproductive season has selective variation. Evidence for adaptation by time demands four factors: 1) time restricts gene flow, 2) the reproductive season expresses variations in phenotypic traits, 3) temporal variation is controlled genetically (it is not plastic), and 4) temporal variation is adaptive. ABT increases, "as (i) selection on the trait increases; (ii) environmental influences on reproductive time decrease; (iii) the heritability of reproductive time increases; and (iv) the temporal distribution of reproductive activity becomes increasingly uniform."
Detecting allochrony
Because allochronic speciation can occur in conjunction with other modes and forms of speciation, researchers must attempt to determine if the initial stages of isolation were the result of allochrony. The speciation continuum of allopatry, parapatry, and sympatry have all been implicated in studies of temporal isolation. Allochrony can also facilitate reinforcement after secondary contact. The frequency of allochronic speciation is thought to common but understudied as allochrony is widespread in nature.
Testing whether or not allochrony prevents gene flow can be difficult due to the multitude of unknown variables in wild populations and the inability to replicate and manipulate it in laboratory settings. Producing viable, and fertile offspring (or the lack thereof) is not always possible; fortunately, lake of mate tests do not necessarily indicate temporal isolation is not at play. As stated prior, one of the necessary criteria is that the species in question must be sister taxa (or demonstrably incipient). This means that accurate phylogenies are vital to determining the initial stage of a speciation event.
Despite the multitude of studies, it is not always evident whether allochrony is the sole driver of speciation or if other factors acting simultaneously are responsible. This can be more challenging when speciation has already occurred (in that the taxa in question are reproductively isolated and no longer incipient). Determining how important allochrony is as a historical cause of speciation can be tested by: 1) comparative studies that show the young pairs of sister taxa are temporally isolated and 2) testing cases of incipient species in sympatry where reproductive isolation is incomplete without temporal isolation.
Determining if allochrony is the source of divergence require a key pattern to be measured: isolation (and subsequently speciation) should correlate with a decrease in overlapping breeding times. This pattern indicates that daily allochrony is more prone to gene flow (closeness of breeding times can allow accidental intermixing of populations) while yearly allochrony is the least prone to gene flow (accidental intermixing is rare if large time frames exist between mating periods).
Examples of divergence driven by allochrony
The following table documents cases of allochronic speciation. Varying degrees of certainty exist as not all cases strongly meet the three primary criteria necessitated by allochronic speciation. Species marked with an asterisk (*) indicate stronger confidence assessed by Rebecca Taylor and Vicki Friesen (2017).
Asynchrony of Seasons Hypothesis
A noteworthy and significant pattern in nature is that of latitudinal gradients in species diversity. where species' richness (biodiversity) increases closer to Earth's equator. It is thought that one contributing factor is that rates of speciation are higher in these regions across the planet. The Asynchrony of Seasons Hypothesis is proposed to be a contributing factor to higher speciation rates as it relates directly to that of allochronic speciation. The hypothesis proposes that the pattern is a result of a lack of synchrony with seasonal variations in tropical regions.
In high-latitude regions, various taxa experience similar temperatures and solar radiation in cyclic patterns due to Earth's axial tilt—generating seasons that are not found at the equator. Because of this, populations of a species have phenologies that are generally synchronous across a range allowing for unimpeded dispersal and subsequent gene flow. This results in less divergence between populations; ultimately reducing rates of speciation (and overall biodiversity).
In contrast with this, latitudes near or at the equator (tropics) experience asynchrony in seasonal variation in that the regions receive similar amounts of solar radiation and maintain consistence temperature. What does change is precipitation patterns, as they can be sporadic, scattered, and vary over very short distances. This pattern causes asynchrony in the phenologies of species populations that can ultimately act as a temporally isolating barrier to reproduction. This prevents gene flow between populations and can drive divergence, speciation, and an increase in biodiversity.
A large scale test of the hypothesis was conducted on fifty-seven New World bird species across South, Central, and North America. The findings, using DNA, geographic and ecological distances, as well as climatic data, indicated that genetic differentiation increased in species populations where asynchrony in precipitation was present. A similar pattern was found in another study of forty-eight neotropical frogs.
References
Speciation | Allochronic speciation | [
"Biology"
] | 2,666 | [
"Evolutionary processes",
"Speciation"
] |
66,148,455 | https://en.wikipedia.org/wiki/WY%20Sagittae | WY Sagittae, also known as Nova Sagittae 1783, is a star in the constellation Sagitta which had a nova eruption visible in 1783. It was discovered on 26 July 1783 by the French astronomer Joseph Lepaute D'Agelet. It is usually difficult to precisely identify novae that were discovered hundreds of years ago, because the positions were often vaguely reported (for example the discoverer may have only reported the constellation where the nova occurred) and historically there was not a clear distinction drawn between different sorts of transient astronomical events such as novae and comet apparitions. However D'Agelet observed this nova with a mural quadrant, which produced coordinates accurate enough to allow modern astronomers to identify the star. D'Agelet reported the apparent magnitude of the star as 6, but Benjamin Apthorp Gould, who analysed D'Agelet's records, determined that what D'Agelet called magnitude 6 corresponds to magnitude 5.4 ± 0.4 on the modern magnitude scale, so the nova was visible to the naked eye.
Very little is known about WY Sagittae's post-eruption light curve. D'Agelet reported the star's magnitude as 6, 6 and 6.7 on the 26th, 27th and 29 July 1783, respectively. At least a half dozen observers attempted to find D'Agelet's nova in the late 19th and early 20th centuries, without success. In 1942 a photographic search for the nova was performed using the 60-inch telescope on Mt. Wilson, and in 1950 Harold Weaver tentatively identified a faint blue star with a photographic magnitude of 18.9 as the quiescent nova. The star was only a few arc seconds away from D'Agelet's reported position, and fluctuations in its brightness added to the confidence that it was indeed the nova. In 1971 Brian Warner observed Weaver's candidate for WY Sagittae with the Otto Struve Telescope, and saw rapid brightness variations that are ubiquitous in quiescent novae, which confirmed Weaver's identification of D'Agelet's nova.
All novae are binary stars, with a "donor" star orbiting a white dwarf. The two stars are so close together that matter is transferred from the donor star to the white dwarf. Because the distance between the stars is comparable to the radius of the donor star, novae are often eclipsing binaries, and WY Sagittae does show eclipses.
The eclipses, which are quite deep (two magnitudes), show that the binary's orbital period is 3 hours and 41 minutes. Christian Knigge classified the donor star's spectral type as M4±1. Somers et al. estimate the donor star's spectral type to be between M3.5 and M4.5, and the mass of the white dwarf to lie between and .
Özdönmez et al. estimate WY Sagittae's distance to be 4200±400 parsecs, based on reddening.
WY Sagittae is sometimes listed as the second oldest "recovered" nova (meaning a historical nova for which modern observations have unambiguously identified the post-nova star), with only CK Vulpeculae being older. But
Naylor et al. argue that CK Vulpeculae is not a nova, and WY Sagittae is the oldest recovered nova.
References
Novae
Sagitta
Sagittae, WY
Eclipsing binaries | WY Sagittae | [
"Astronomy"
] | 726 | [
"Novae",
"Astronomical events",
"Sagitta",
"Constellations"
] |
66,148,740 | https://en.wikipedia.org/wiki/FAM237A | FAM237A is a protein coding gene which encodes a protein of the same name. Within Homo sapiens, FAM237A is believed to be primarily expressed within the brain, with moderate heart and lesser testes expression,. FAM237A is hypothesized to act as a specific activator of receptor GPR83.
Gene
FAM237A is alternatively known as HCG1657980 and LOC200726. Homo sapiens FAM237A's sequence resides on chromosome 2’s + strand, and extends from bases 207486904 to 207514174. Homo sapiens FAM237A sequence contains 13 exons unspliced.
Transcripts
Homo sapiens FAM237A is predicted to produce six unique transcripts, of which four are spliced.
Proteins
Homo sapiens FAM237A is associated with three unnamed protein isoforms. FAM237A's most-researched isoform is 181 amino acids long, and is predicted to contain a transmembrane domain. FAM237A's second protein isoform is predicted to be 417 amino acids long; it contains a transmembrane domain and an upstream open reading frame. The last protein isoform of FAM237A is made up of 158 amino acids and contains a transmembrane domain; this isoform is predicted to localize within the membrane. Several databases, including NCBI, only recognize FAM237A's 181 amino acid isoform. Given the relative abundance of literature surrounding it, the remainder of this page's findings only discuss FAM237A's 181 amino acid isoform.
The theoretical molecular weight of this isoform is 20.56 kDA. Its theoretical isoelectric point is 8.96. Homo sapiens FAM237A amino acid composition is predicted to be relatively standard. It notably contains a repeat LFWD motif at amino acids 90 and 97.
FAM237A's transmembrane domain is generally predicted to reside on amino acids 14-32 within the protein. However, structure prediction tool Phyre2 predicts that the protein's transmembrane domain resides on amino acids 91–106.
Regulation
Three promoters of Homo sapiens FAM237A are predicted: GXP_8991091, GXP_7539237, and GXP_8991092. Of these, GXP_8991091 has the greatest predicted tissue expression levels.
AceView predicts that Homo sapiens FAM237A is localized to membranes. However, this is disputed, with protein localization prediction resource Hum-mPLoc predicting that Homo sapiens FAM237A is expressed within the nucleus and resource PSORT II predicting ER localization, with lesser chances of expression within the mitochondria and Golgi apparatus.
An abundance of predicted phosphorylation sites reside on Homo sapiens FAM237A's sequence. Homo sapiens FAM237A contains two predicted fatty acid addition sites at amino acids 18 and 26; these sites overlap with one of the FAM237A's predicted transmembrane sequences. Homo sapiens FAM237A is additionally predicted to contain two sites of ubiquitination at amino acids 179 and 181 on its sequence. These ubiquitination sites are predicted to perfectly overlap two acetylation sites.
Homology
Homo sapiens FAM237A has one predicted paralog: FAM237B. FAM237B has 21.6% predicted identity with FAM237A
FAM237A has orthologs in a broad range of vertebrate organisms, including other Mammals, Reptilia, Actinopterygii, and Aves. The gene is not found in invertebrates. Based upon BLAST analysis, FAM237A is not found in invertebrates. The only reptiles which FAM237A is found in are predicted to be of the suborder Cryptodira, based upon BLAST searches.
Function
Information regarding FAM237A's function is limited; however, FAM237A is predicted to be a specific activator of GPR83, which is implicated in energy metabolism, dietary patterns, and reward signaling. GPR83 is additionally suspected to be correlated to immune system function
References
Genes
Proteins | FAM237A | [
"Chemistry"
] | 931 | [
"Biomolecules by chemical classification",
"Proteins",
"Molecular biology"
] |
66,153,199 | https://en.wikipedia.org/wiki/NV-5440 | NV-5440 is a drug which acts as both a non-specific inhibitor of the glucose transporters and also a selective inhibitor of mTORC1, with no significant action at the related mTORC2 subtype. Compounds of this type have potential application in the treatment of cancer, and it is also used for research into the links between calorie restriction and longevity.
References
Enzyme inhibitors
N-benzoylpiperazines | NV-5440 | [
"Chemistry"
] | 91 | [
"Pharmacology",
"Pharmacology stubs",
"Medicinal chemistry stubs"
] |
66,153,538 | https://en.wikipedia.org/wiki/Kinkeeping | Kinkeeping is the act of maintaining and strengthening familial ties. It is a form of emotional labor done both out of a sense of obligation and because of emotional attachment. Sociologist Carolyn Rosenthal defined the term in her 1985 article, "Kinkeeping in the Familial Division of Labor". According to her, kinkeepers play an important role in maintaining family cohesion and continuity. Their efforts contribute significantly to the family's social capital, providing emotional support and a sense of belonging to family members.
Kinkeeping activities help extended family members of differing households stay in touch with one another and strengthen intergenerational bonds. It facilitates the transfer of family traditions, values, and histories from one generation to the next. Families with active kinkeepers tend to feel more connected as a family.
Kinkeeping methods may include telephone calls, writing letters, visiting, sending gifts, acting as a caregiver for disabled or infirm family members, or providing economic aid. Maintaining family traditions, such as preparing particular foods for holidays, is a form of kinkeeping.
Women are more likely to act as kinkeepers than men and often organize family events and reunions. A 2006 survey of three different cohorts of Americans including those born before 1930, 1946–1964, and 1965–1976 found that women reported more contact with relatives than men in every cohort.
Kinkeeping tends to be time-consuming. The kinkeepers may enjoy their role, or they may find it burdensome.
References
Interpersonal relationships
Family | Kinkeeping | [
"Biology"
] | 306 | [
"Behavior",
"Interpersonal relationships",
"Human behavior"
] |
66,153,716 | https://en.wikipedia.org/wiki/Abelian%202-group | In mathematics, an Abelian 2-group is a higher dimensional analogue of an Abelian group, in the sense of higher algebra, which were originally introduced by Alexander Grothendieck while studying abstract structures surrounding Abelian varieties and Picard groups. More concretely, they are given by groupoids which have a bifunctor which acts formally like the addition an Abelian group. Namely, the bifunctor has a notion of commutativity, associativity, and an identity structure. Although this seems like a rather lofty and abstract structure, there are several (very concrete) examples of Abelian 2-groups. In fact, some of which provide prototypes for more complex examples of higher algebraic structures, such as Abelian n-groups.
Definition
An Abelian 2-group is a groupoid (that is, a category in which every morphism is an isomorphism) with a bifunctor and natural transformations
which satisfy a host of axioms ensuring these transformations behave similarly to commutativity () and associativity for an Abelian group. One of the motivating examples of such a category comes from the Picard category of line bundles on a scheme (see below).
Examples
Picard category
For a scheme or variety , there is an Abelian 2-group whose objects are line bundles and morphisms are given by isomorphisms of line bundles. Notice over a given line bundle
since the only automorphisms of a line bundle are given by a non-vanishing function on . The additive structure is given by the tensor product on the line bundles. This makes is more clear why there should be natural transformations instead of equality of functors. For example, we only have an isomorphism of line bundles
but not direct equality. This isomorphism is independent of the line bundles chosen and are functorial hence they give the natural transformation
switching the components. The associativity similarly follows from the associativity of tensor products of line bundles.
Two term chain complexes
Another source for Picard categories is from two-term chain complexes of Abelian groups
which have a canonical groupoid structure associated to them. We can write the set of objects as the abelian group and the set of arrows as the set . Then, the source morphism of an arrow is the projection map
and the target morphism is
Notice this definition implies the automorphism group of any object is . Notice that if we repeat this construction for sheaves of abelian groups over a site (or topological space), we get a sheaf of Abelian 2-groups. It could be conjectured if this can be used to construct all such categories, but this is not the case. In fact, this construction must be generalized to spectra to give a precise generalization. pg 88
Example of Abelian 2-group in algebraic geometry
One example is the cotangent complex for a local complete intersection scheme which is given by the two-term complex
for an embedding . There is a direct categorical interpretation of this Abelian 2-group from deformation theory using the Exalcomm category.
Note that in addition to using a 2-term chain complex, would could instead consider a chain complex and construct an Abelian n-group (or infinity-group).
Abelian 2-group of morphisms
For a pair of Abelian 2-groups there is an associated Abelian 2-group of morphisms
whose objects are given by functors between these two categories, and the arrows are given by natural transformations. Moreover, the bifunctor on induces a bifunctor structure on this groupoid, giving it an Abelian 2-group structure.
Classifying abelian 2-groups
In order to classify abelian 2-groups, strict Picard categories using two-term chain complexes is not enough. One approach is in stable homotopy theory using spectra which only have two non-trivial homotopy groups. While studying an arbitrary Picard category, it becomes clear that there is additional data used to classify the structure of the category, it is given by the Postnikov invariant.
Postnikov invariant
For an Abelian 2-group and a fixed object the isomorphisms of the functors and given by the commutativity arrow
gives an element of the automorphism group which squares to , hence is contained in some . Sometimes this is suggestively written as . We can call this element and this invariant induces a morphism from the isomorphism classes of objects in , denoted , to , i.e. it gives a morphism
which corresponds to the Postnikov invariant. In particular, every Picard category given as a two-term chain complex has because they correspond under the Dold-Kan correspondence to simplicial abelian groups with topological realizations as the product of Eilenberg–MacLane spaces
For example, if we have a Picard category with and , there is no chain complex of Abelian groups giving these homology groups since can only be given by a projection
Instead this Picard category can be understood as a categorical realization of the truncated spectrum of the sphere spectrum where the only two non-trivial homotopy groups of the spectrum are in degrees and .
See also
∞-groupoid
n-group
Gerbe
References
Thesis of Hoàng Xuân Sính (Gr Categories)
- gives techniques for defining sheaf cohomology with coefficients in a crossed module, or a Picard category
- exposition of stable 1-types containing relation with picard categories
2-group
Algebraic topology
Homological algebra | Abelian 2-group | [
"Mathematics"
] | 1,143 | [
"Mathematical structures",
"Algebraic topology",
"Fields of abstract algebra",
"Topology",
"Category theory",
"Homological algebra"
] |
66,154,225 | https://en.wikipedia.org/wiki/GUVI | GUVI (named as an acronym of Grab Your Vernacular Imprint) is an online platform to learn computer programming based in India. It offers free and paid coding courses to students and working professionals in Indian languages such as Hindi, Telugu, Kannada, Swahili, Bengali, Tamil, and in English. GUVI's mission is "to make technical education available to all in their native languages".
History
GUVI was started as a YouTube channel in 2011. The channel posted video tutorials, courses, and practice materials created by Arun Prakash, Sridevi Arun Prakash, and SP Balamurugan. The videos were posted in Tamil, Telugu, and Marathi, with the goal of reaching people not fluent in English.
The trio quit their job in 2014 and started GUVI as a company. Seeded with an initial capital of ₹1,000,000, the start-up was incubated at the Rural Technology and Business Incubator (RTBI) based out of IIT Madras. The start-up raised seed funding of ₹500,000, and officially launched in November 2014.
GUVI received its first institutional round of funding of ₹10,000,000, from US-based Gray Matters Capital's edLABS in April 2019. It raised ₹60,000,000 in its pre-series A round of funding from Education Catalyst Fund, an education-focused venture capital fund managed by CBA Capital, in April 2020
Events
GUVI conducted All India Robotic Process Automation Skillathon, with UiPath, in June 2020, to provide students an opportunity to get exposure to robotic process automation. The event included over 400 colleges across India and over 60,000 participants
GUVI offered free online coding courses in March 2020 (during the COVID-19 pandemic lockdown in India).
Co-founder Sridevi Arun Prakash died on 20 September 2020 due to Breathing problem.
Recognition and awards
GUVI was supported by Google's Launchpad Accelerator Program in 2017.
References
Computer programming
Indian educational websites | GUVI | [
"Technology",
"Engineering"
] | 410 | [
"Software engineering",
"Computer programming",
"Computers"
] |
66,155,057 | https://en.wikipedia.org/wiki/Electrified%20reef | An electric reef (also electrified reef) is an artificial reef made from biorock, being limestone that forms rapidly in seawater on a metal structure from dissolved minerals in the presence of a small electric current. The first reefs of this type were created by Wolf Hilbertz and Thomas J. Goreau in the 1980s. By 2011 there were examples in over 20 countries.
History
Artificial reefs have been built since the 1950s using materials including sunken ships and concrete blocks. While artificial reefs have been effective at boosting fish populations and are valuable areas for benthic organisms and other marine life (e.g. sponges) to colonise, they are less viable for coral restoration due to the slow growth of corals and their susceptibility to environmental changes.
In the 1970s, whilst studying how seashells and reefs grow, Wolf Hilbertz discovered a simple method of creating limestone from minerals dissolved in seawater, which he called biorock. Together with Thomas J. Goreau he realised that this process could be adapted to rapidly create artificial coral reefs during the 1980s. Using the names "Sea-ment" and "sea cement", the process was publicised in the 1992 futurology book titled The Millennial Project.
With others, Hilbertz and Goreau made expeditions to the Saya de Malha bank in 1997 and 2002 where they grew an artificial island around steel structures anchored to the sea floor using this process. In the Maldives, 80% of the electric reefs survived the 1998 warming which killed 95% of the natural reef corals.
Goreau continued the work after Hilbertz's death in 2007. By 2011 there were electric reef projects installed in over 20 countries. In 2012, both Goreau and Robert K. Trench published works on how the process could generate building materials as well as restore damaged ecosystems.
Construction process
The base of an electrified reef is a welded electrically conductive frame, often made from construction grade rebar or wire mesh which submerged and attached to the seafloor to which an electrical field applied. The frame (cathode) and a much smaller metal plate (anode) placed at a suitable distance from the frame initiates the electrolytic reaction.
Dissolved calcium carbonate and magnesium hydroxide and other minerals naturally found in seawater breakdown in the vicinity of the anode and recombine and precipitate out of the water onto the cathode. The exact composition of the minerals within the crystal formation is depends on their abundance, the climatic conditions and the voltage used. The structure takes on a whitish appearance within days.
This electric field, together with shade and protection offered by the metal/limestone frame soon attracts colonizing marine life, including fish, crabs, clams, octopus, lobster and sea urchins. Once the structure is in place and minerals begin to coat the surface divers transplant coral fragments from other reefs to the frame which soon bond to the newly accreted mineral substrate.
Because of the availability of evolved oxygen at the cathode and the electrochemically facilitated accretion of dissolved ions such as bicarbonate, they start to grow, some three to five times faster than normal and soon the reef takes on the appearance and utility of a natural reef ecosystem.
As shore protection
Shorelines are increasingly susceptible to beach erosion and loss due to climate change which is resulting in rising sea levels and increasingly frequent and more powerful storms. Large structures such as breakwaters constructed to reflect waves to prevent erosion are problematic and can in fact contribute to further beach erosion since for force of waves is doubled due to the reversal of the wave direction vector with the reflected wave carrying sand from the structure's base back out to sea resulting in the structure failing over time.
Common electrified reef used for shore protection mimic the effect of a natural reef which prevent erosion by dissipating wave energy and causing waves to break before they impact the shore. In nature, large reefs, have been shown to dissipate up to 97% of their energy. They are based around the same open mesh frameworks as those used for coral restoration. Skeletons of dead coral and algae from the reef are then deposited and help grow beaches. Because these reefs mimic the properties of natural reefs they solve some of the challenges they have in storm dissipation and their self-healing qualities helps structures survive extreme storms as long as the electricity supply remains in operation.
In Turks and Caicos trials of electrified reefs of coastal protection survived the two worst hurricanes in the history of the islands, which occurred three days apart and damaged or destroyed 80% of the buildings on the island. Sand was observed to build up around the bases of the reef structure.
In Maldives in 1997, shore protection reefs helped save several buildings, including a hotel, that had risked washing away due to severe beach erosion. The 50-meter-long shore protection reef stabilized and ultimately reversed erosion in several years, even allowing the beach to survive a tsunami in 2004.
Distribution
Electric reef projects had been installed in over 20 countries, in the Caribbean, Indian Ocean, Pacific and Southeast Asia. Projects are located in French Polynesia, Indonesia, Maldives, Mexico, Panama, Papua New Guinea, Seychelles, the Philippines, Thailand and on one of the most remote and unexplored reef areas of the world, the Saya de Malha Bank in the Indian Ocean.
Indonesia has the most reef projects, with sites near over half a dozen islands, including the world's two largest reef restoration projects: Pemuteran with the Karang Lestari and the Gili islands with the Gili Eco Trust.
Non-coral reef projects have been conducted in places such as Barataria Bay, Galveston, seagrasses in the Mediterranean, oyster reefs and salt marshes in New York City, in Port Aransas, and in St. Croix.
Effectiveness
Electrolysis of electric reefs enhances coral growth, reproduction and ability to resist environmental stress. Coral species typically found on healthy reefs gain a major advantage over the weedy organisms that often overgrow them on stressed reefs.
Biorock can enable coral growth and regrowth even in the presence of environmental stress such as rising ocean temperatures, diseases, and nutrient, sediment, and other types of pollution. Biorock represents the only known method that can sustain and grow natural coral species using only basic conducting elements, typically of a common metal such as steel.
The process accelerated growth on coral reefs by as much as fivefold and restoration of physical damage by as much as 20 times. and the rate of growth can be varied by altering the amount of current flowing into the structure.
In one study, Porites colonies with and without an electric field were compared for 6 months after which time the current to the electric reef was eliminated. Growth differences were significant only during the first 4 months with longitudinal growth being relatively high in the presence of the field. The treatment corals survived at a higher rate.
On Vabbinfaru island in the Maldives, a 12-meter, 2 ton steel cage called the Lotus was secured on the sea floor. As of 2012, coral was so abundant on the structure that the cage is difficult to discern. The 1998 El Nino killed 98% of the reef around Vabbinfaru. Abdul Azeez, who led the Vabbinfaru project, said coral growth on the structure is up to five times that of elsewhere. A smaller prototype device was in place during the 1998 warming event and more than 80% of its corals survived, compared to just 2% elsewhere. However, power is no longer supplied to the project, leaving it vulnerable to the next round of bleaching.
Drawbacks
Electric reefs require electrical power to maintain them. In Maldives, several electric reefs successfully survived a 1998 bleaching event that killed off nearly all local wild coral, however after being depowered they were killed by the bleaching event of 2016.
A study conducted in the Bahamas in 2015 showed that the electric field deterred sharks, specifically the bull shark and the Caribbean reef shark, from swimming and feeding in the area. The electric field is believed to affect sharks because of their electroreception abilities, however species with similar capabilities such as the bar jack and Bermuda chub did not appear to be affected by the electric field.
See also
Gili Eco Trust
References
Further reading
"Changes in zooxanthellae density, morphology, and mitotic index in hermatypic corals and anemones exposed to cyanide", 2003
Goreau + Hilbertz: "Marine Ecosystem Restoration: Costs and benefits for coral reefs", World Resource Review, 2005
Vaccarella, R. + Goreau: "Applicazione della elettrodeposizione nel recupero die mattes di Posidonia oceanica", 2008
Goreau + Hilbertz, "Bottom-Up Community-Based Coral Reef and Fisheries Restoration in Indonesia, Panama, and Palau", 2008
Goreau + Hilbertz, "Reef Restoration as a Fisheries Management Tool", UK 2008, on GCRA website
Strömberg + Lundälv + Goreau: "Suitability of Mineral Accretion as a Rehabilitation Method for Cold-Water Coral Reefs", 2010
"Effect of severe hurricanes on Biorock Coral Reef Restoration Projects in Grand Turk, Turks and Caicos Islands", 2010
Goreau, T. J.: "Coral Reef and Fisheries Habitat Restoration in the Coral Triangle", Indonesia 2010
External links
Wolf Hilbertz website
Global Coral Reef Alliance
Biorock.net
CCell Supplier of equipment
Marine biology | Electrified reef | [
"Biology"
] | 1,928 | [
"Marine biology"
] |
66,155,590 | https://en.wikipedia.org/wiki/LinBi | The LinBi project ran between February 2019 and October 2020 as an EU-funded INEA-CEF project which focused on biodiversity and documentation of the variety of life on Earth. This diversity is preserved in a wide range of formats – books, illustrations, specimen scans, glass plate photographs, sound recordings, herbarium sheets, video and more. LinBi brought together botanists, researchers, the media and the public in a collaborative effort to enhance and support appreciation and use of European biodiversity material. The project has provided 1.3 million items of cultural heritage content to Europeana.
LinBi partners were:
Rundfunk Berlin-Brandenburg (RBB, Germany) public service broadcaster for the German region of Berlin and Brandenburg,
Royal Botanical Garden of Madrid (RJB-CSIC, Spain) part of the Spanish National Research Council (CSIC),
Naturhistorisches Museum Wien (NHM, Austria) which includes departments of anthropology, botany, geology, mineralogy, karst and caves, palaeontology and zoology
Angewandte Informationstechnik Forschungsgesellschaft (AIT, Austria) an Austrian software and research company specialising in information engineering and development of information systems tailored to complex environments in public administration, social/youth welfare and health care,
Agentschap Plantentuin Meise (APM, Belgium), an internationally renowned research institution focussing on plant diversity research and conservation.
Technical Overview
LinBi created a data enrichment platform to link existing items of data with new items, creating ‘enriched’ information objects. These were then processed by the OpenUp! Natural History content aggregator and provided to Europeana. The project has created three virtual exhibitions for Europeana. These exhibitions interlinked existing content with new and external data. The exhibitions focussed on Edible Plants from the Americas (curated by RJB-CSIC), François Crépin and the Study of Wild Roses (curated by Meise) and Magical, Mystical and Medicinal – Psychoactive plants and fungi, (curated by RJB-CSIC).
Publications
Huybrechts P, Alonso-Sánchez F, Böttinger P, Dillen M, Groom Q, Hanquart N, Koch W, Gordon M, Mergen P (2019): ‘LinBi: Linking biodiversity and culture information. Biodiversity Information Science and Standards’
Alonso Sánchez, F. (2019): ‘LinBi: descubriendo, interconectando y enriqueciendo el conocimiento digital sobre la biodiversidad europea’
Huybrechts P, Böttinger P, Fabri R, Hanquart N, Koch G, Mergen P, Rainer H, Gordon M (2020): ‘Citizen Science as a Tool for Connecting Cultural Heritage and Natural History Collections: Providing Valuable Opportunities for Enrichment, Linked Data and FAIRness’
Pablo Vargas Gomez ed. (2020): ‘En búsqueda de las especias – Las plantas de la expedicion Magellanes-Elcano (1519–1522)’
Hanquart N, Hoste I, Soffelen P (2020): ‘François Crépin and the study of wild roses: A rose is a rose is a rose – a virtual exhibition from Europeana’ (French and Flemish)
Huybrechts P, Trekels M, Dillen M, Groom Q, Mergen P, Gordon M (2020): ’Feasibility of 3D and video metadata annotation using crowdsourcing platforms’ (to be published in Research Ideas and Outcomes (RIO) early 2021)
References
Further info
European Union
Cultural heritage
Biodiversity
Biogeography
Conservation biology
Species | LinBi | [
"Biology"
] | 756 | [
"Biogeography",
"Conservation biology",
"Biodiversity"
] |
66,155,598 | https://en.wikipedia.org/wiki/Yvan%20Bruynseraede | Yvan J. Bruynseraede (born 1938 in Ostend, Belgium) is a condensed matter experimental physicist, known for his work on multilayers and superlattices, and his interests are thin films, nanostructures, novel materials, magnetism, and superconductivity. He is currently Professor Emeritus at the Catholic University of Leuven (KULeuven), and a member of the Quantum Solid-State Physics Laboratory.
Academic career
Yvan Bruynseraede graduated (Belgian Licentiate) in 1961 from the KULeuven where he received his PhD in Physics in 1967, after a two-year interruption for military service.
After a postdoctoral and associate fellowship at CERN, Switzerland (1968–1971), he started his career as a lecturer at KULeuven in 1972 and became full professor in 1977. He was chairman of the Laboratory of Solid-State Physics and Magnetism, KULeuven (1993–2003). In 2003 he became professor emeritus of physics at KU Leuven, a position in which he is currently active. He held visiting positions at Université Côte d'Azur, Nice, France; the Argonne National Laboratory, US; and the University of California at San Diego, US.
Scientific research
At CERN he was active in the development of a superconducting particle separator by studying the HF properties of superconducting materials for electromagnetic cavities.
At KU Leuven, his research was mainly focused on superconductivity and magnetism. He studied the electrical, magnetic and optical properties of mesoscopic and nanoscopic systems, particularly at low temperatures and very high magnetic fields. He performed research on thin films, multilayers and superlattices, studying superconducting Josephson phenomena, tunneling and vortices;
superconducting/magnetic interactions; X-ray structural analysis and SPM techniques applied to surfaces and interfaces. His research activities resulted in more than 450 publications in international scientific journals, 100 Invited talks, and the promotorship of 35 PhD and 70 MSc theses.
Distinctions and awards
Recipient, Grand Officer of the Order of Leopold (Belgium) (Grootofficier in de Leopoldsorde) (2013)
Member (1988–present) and President (1999–2000), The Royal Flemish Academy of Belgium for Science and the Arts (Koninklijke Vlaamse Academie voor Wetenschappen en Kunsten)
Member, The European Academy of Sciences and Arts, Vienna, Austria (2001–present)
Member, The Royal Society of Arts and Sciences in Gothenburg, Sweden (2005–present)
Fellow, American Physical Society (1990–present)
Member, Board of Trustees, KU Leuven (2003–2013)
Member, Association Council, KU Leuven (2003–2013)
Member, Board of Governors, Nuclear Research Center SCK CEN, Mol (1991 – 2013)
Chair, Research Council, KU Leuven (1990–1995)
Chair, American Physical Society “Forum on Outreach and Engaging the Public" (FOEP) (2016)
Recipient, IUMRS SOMIYA Award, together with Ivan K. Schuller of UCSD (2007)
References
1938 births
Living people
Belgian physicists
KU Leuven alumni
Members of the European Academy of Sciences and Arts
Academic staff of KU Leuven
Members of the Royal Society of Sciences and Letters in Gothenburg
Fellows of the American Physical Society
People from Ostend
20th-century physicists
21st-century Belgian scientists
20th-century Belgian scientists
21st-century physicists
Condensed matter physicists
People associated with CERN | Yvan Bruynseraede | [
"Physics",
"Materials_science"
] | 741 | [
"Condensed matter physicists",
"Condensed matter physics"
] |
66,156,462 | https://en.wikipedia.org/wiki/Pascal%20Saikaly | Pascal Elias Saikaly is a Lebanese professor of Environmental Science and Engineering. He is best known for the use of omics for applied studies of microbiology in engineered and natural wastewater treatment systems, including bioelectrochemistry, membrane bioreactors, and granular sludge.
Saikaly collaborates with and leads teams of scientist and engineers who have developed novel approach to harvest electrical energy from wastewater while simultaneously producing useful byproducts. In particular, he combines advances from nanotechnology and materials research with advances from microbial ecology to develop devices to create bioelectricity. This work supports the long-term strategic efforts of the King Abdullah University of Science and Technology to research and commercialize alternative sources of energy. Saikaly's research addresses broader issues of importance in water-limited environments, including the use of seawater for toilet flushing.
Education
Saikaly earned his B.S. and M.S. from the American University of Beirut. In 2005, he completed his Ph.D. at the University of Cincinnati. From 2005 to 2007, he was completed postdoctoral studies at North Carolina State University. From 2008 to 2010, he was an assistant professor at the American University of Beirut. In 2010, he joined the faculty of King Abdullah University of Science and Technology, where he is currently a full professor.
Bibliography
Saikaly has more than 100 publications listed on Scopus that have been cited a total of more than 3000 times, giving him an h-index of more than 30. His most cited articles include:
<li>
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References
External links
Google Scholar
Environmental scientists
Living people
University of Cincinnati alumni
Academic staff of King Abdullah University of Science and Technology
Year of birth missing (living people) | Pascal Saikaly | [
"Environmental_science"
] | 354 | [
"Environmental scientists"
] |
54,803,622 | https://en.wikipedia.org/wiki/Malcolm%20von%20Schantz | Malcolm von Schantz FLS (born May 1966) is a professor of chronobiology at Northumbria University. His research relates to circadian rhythms and sleep in human beings and its molecular determinants. He is a Special Visiting Scientist at the University of São Paulo School of Medicine and a fellow of the Linnean Society. He is part of the international team that determined that urbanisation and electricity are not to blame for sleep loss.
Selected publications
From Genes to Genomes: Concepts and Applications of DNA Technology. Wiley-Blackwell, 2007. (With Jeremy W. Dale)
References
External links
Researchgate profile
Living people
Academics of the University of Surrey
Fellows of the Linnean Society of London
1966 births
Swedish scientists
Lund University alumni
Sleep researchers | Malcolm von Schantz | [
"Biology"
] | 154 | [
"Sleep researchers",
"Behavior",
"Sleep"
] |
54,804,319 | https://en.wikipedia.org/wiki/Stilbonematinae | Stilbonematinae is a subfamily of the nematode worm family Desmodoridae that is notable for its symbiosis with sulfur-oxidizing bacteria.
Systematics
Stilbonematinae Chitwood, 1936 belongs to the family Desmodoridae in the order Desmodorida. Nine genera have been described.
Adelphos Ott, 1997
Catanema Cobb, 1920
Centonema Leduc, 2013
Eubostrichus Greeff, 1869
Laxus Cobb, 1894
Leptonemella Cobb, 1920
Parabostrichus Tchesunov et al. 2012
Robbea Gerlach, 1956
Squanema Gerlach, 1963
Stilbonema Cobb, 1920
Description
Stilbonematines can be up to 10 mm long, with a club-like head. The worms are completely covered in a coat of ectosymbiotic sulfur-oxidizing bacteria except for the anterior region. The presence of the bacteria, which often contain intracellular inclusions of elemental sulfur, gives the worms a bright white appearance under incident light. They have small mouths and buccal cavities, and short pharynges. Many species have multicellular sensory-glandular organs in longitudinal rows along the length of the body, which secrete mucus that the bacterial symbionts are embedded in.
Stilbonematines are found in the meiofaunal habitat in marine environments. Another group of meiofaunal nematodes with sulfur-oxidizing symbionts is the genus Astomonema, although in Astomonema the bacteria are endo- rather than ectosymbionts.
Symbiosis with sulfur-oxidizing bacteria
The bacterial symbionts of stilbonematines are of different shapes and sizes, ranging from small coccoid cells to elongate crescent-like cells, but each host species has only a single morphological type associated with it. The bacterial symbionts of stilbonematines are closely related to the sulfur-oxidizing symbionts of gutless phallodriline oligochaete worms: these bacteria were all descended from a single ancestor, and each host species has its own specific bacterial species.
The bacterial symbionts are chemosynthetic, gaining energy by oxidizing sulfide from the environment, and producing biomass by fixing carbon dioxide through the Calvin-Benson-Bassham cycle. The bacteria benefit from the symbiosis because the host animal can migrate between sulfide- and oxygen-rich regions of the sediment habitat, and the bacteria require both these chemical substances to produce energy. The hosts are believed to consume the bacteria as a food source, based on evidence from their stable carbon isotope ratios.
The specificity of the bacterial symbionts to their respective host species is controlled by a lectin called Mermaid that is produced by the worms. Mermaid occurs in different isoforms, which have differing affinities for the sugar compositions of the lipopolysaccharide coat in different bacterial species.
See also
Olavius algarvensis - A species of gutless phallodriline oligochaete worms whose sulfur-oxidizing bacterial symbionts are related to those of the stilbonematine nematodes.
Astomonema - A genus of nematodes (from a different family) that also has symbiotic sulfur-oxidizing bacteria.
References
Chromadorea
Chemosynthetic symbiosis | Stilbonematinae | [
"Biology"
] | 721 | [
"Biological interactions",
"Chemosynthetic symbiosis",
"Behavior",
"Symbiosis"
] |
54,805,001 | https://en.wikipedia.org/wiki/Physoderma%20maydis | Physoderma maydis is a species of fungus in the family Physodermataceae. It is a pathogen of the maize, causing a disease known as brown spot of maize or brown spot of corn. This species was first labeled in 1910 in India, then again a year later in Illinois.
References
Fungal plant pathogens and diseases
Blastocladiomycota
Fungi described in 1909
Fungus species | Physoderma maydis | [
"Biology"
] | 83 | [
"Fungus stubs",
"Fungi",
"Fungus species"
] |
54,805,698 | https://en.wikipedia.org/wiki/Elizabeth%20Langdon%20Williams | Elizabeth Langdon Williams (February 8, 1879 – 1981) was an American human computer and astronomer whose work helped lead to the discovery of Pluto, or Planet X.
Personal life and education
Elizabeth Langdon Williams was born to Elizabeth Brigham and Louis M. Williams on February 8, 1879 in Putnam, Connecticut. She was the twin of Robert Longfellow Williams, and the older sister of Henry Trumbell Williams and Ursula Louise Williams. She graduated from MIT with a degree in physics in 1903 as one of their earliest female graduates, and was the first woman to play an honor part during graduation. She read part of her thesis, "An analytical study of the Fresnel wave-surface" at the ceremony, and was said to have widely impressed all in attendance. She was at the top of her class and said to be ambidextrous, writing cursive with her right hand and print with her left hand. In 1922, Williams married George Hall Hamilton, another astronomer who was born in London on June 30, 1884 and educated at Cambridge. He worked at the Lowell Observatory in Flagstaff, Arizona, where he met Williams, from 1917 to 1922.
Career
Williams was hired by Percival Lowell in 1905 to work from his State Street office in Boston. She initially edited publications for Lowell until she was asked to be a human computer for his Planet X research that began in 1910.
Planet X
Lowell hypothesized that a proposed Planet X affected the orbits of the known planets Neptune and Uranus. Williams' role in the Planet X project was that of head human computer, performing mathematical calculations on where Lowell should search for an unknown object and its size based on the differences in the orbits of Neptune and Uranus. Her calculations led to predictions for the location of the unknown planet, but Lowell died in 1916 and the project was discontinued. In the late 1920s, however, the project was resumed and Clyde Tombaugh was hired to lead it. Tombaugh used Lowell's predictions (built on Williams' calculations) to locate an image in a region of the sky photographed in 1915 that he identified as a new planet named Pluto in 1930.
Williams continued to work on calculations and handled correspondence at Lowell Observatory after Lowell's death, moving from Boston to the observatory itself at Flagstaff in 1919. She and Hamilton were then dismissed from their positions at the observatory by Percival Lowell's widow, Constance, because it was considered inappropriate to employ a married woman. Williams and her husband were subsequently employed at an observatory in Mandeville, Jamaica run by Harvard College Observatory where they worked together.
Final years
In 1935, George Hall Hamilton died. Widowed, Williams retired from the observatory in Mandeville and moved to Lebanon, New Hampshire with her younger sister, Louise Ring, where they ran "Peaceful Acres," a summer retreat home. She died in 1981 in Enfield, New Hampshire at the age of 101.
References
1879 births
1981 deaths
American women astronomers
Human computers
American women centenarians
Massachusetts Institute of Technology alumni | Elizabeth Langdon Williams | [
"Technology"
] | 606 | [
"Human computers",
"History of computing"
] |
54,811,351 | https://en.wikipedia.org/wiki/Ilana%20L%C3%B6wy | Ilana Löwy (née Zelmanowicz), born in 1948 in Łódź, Poland, is a historian of biomedical sciences and a feminist. She works as a research director at an interdisciplinary and cross-institutional research unit CERMES-3 (Centre de recherche médecine, sciences, santé, santé mentale, société, Inserm-CNRS-EHESS), and is associated with the Department of Global Health and Social Medicine at King's College London, the Department of the History of Science at Harvard University and Casa de Oswaldo Cruz, Fiocruz, Rio de Janeiro.
Biography
Born in a Jewish family in Poland, her parents decided to leave for Israel in 1957. She gained her Msc in microbiology and biochemistry from Tel Aviv University in 1971, and her PhD (Doctorat D'Etat es Sciences) from Paris VII University in 1977.
Career
At the beginning of her career, Ilana Löwy worked at the Institut Pasteur at the Cellular immunity lab. Her interest in the history of science initially evolved around the history of organ transplantation, bacteriology, immunology, virology and tropical medicine. With an increasing interest in human reproduction and cancer, her work covers an extensive study of biomedical analysis and gender studies. She has extensively published on Ludwik Fleck, Polish historian and philosopher of medicine. Her current (2017) research focuses on prenatal diagnosis, genetics and congenital disorders.
Publications
Authored monographs
The Polish School of Philosophy of Medicine: From Tytus Chalubinski (1820–1889) to Ludwik Fleck (1896–1961), Dordrecht: Kluwer Academic Publications (Philosophy of Medicine Series),1990.
Between Bench and Bedside: Science, Healing and Interleukin-2 in a Cancer Ward, Cambridge, MA: Harvard University Press, 1996 (French translation, Cancer des chercheurs, cancer des cliniciens: Trajectoire d'une innovation thérapeutique, Archives d’Historie Contemporaine, 2002) .
Medical Acts and Medical Facts: The Polish Tradition of Practice Grounded Reflections on Medicine and Science, (in English), Krakow: Polish Academy of Sciences, 2000.
Virus, moustiques et modernité: La fièvre jaune au Brésil entre science et politique, Paris: Archives d’Historie Contemporaine, 2001. (Portuguese translation: Virus, mosquitos e modernidade: A febre amarela no Brasil entre ciência e politica, Rio de Janeiro, Manguinhos, 2005)
L'emprise du genre: Masculinité, féminité, inégalité, Paris: La Dispute, 2006. (Polish translation: Okowy Rodzaju, Bydgoszcz, Epigram, 2012).
Pour en finir avec la domination masculine, Paris: Les Empecheurs de Penser en Rond/ Seuil, 2007. (with Catherine Marry)
Preventive Strikes: Women, Precancer and Prophylactic Surgery, Johns Hopkins University Press, 2009.
A Woman's Disease: A History of Cervical Cancer, Oxford University Press, 2011.
Imperfect Pregnancies. A History of Birth Defects and Prenatal Diagnosis, Johns Hopkins University Press, 2017, .
Tangled Diagnoses: Prenatal Testing, Women, and Risk, Chicago, University of Chicago Press, 2018.
Viruses and Reproductive Injustice. Zika in Brazil, Baltimore, Johns Hopkins University Press, 2024.
Edited volumes
Ilana Löwy (ed.), Medicine and Change: Historical and Sociological Studies of Medical Innovation, Paris & Londres: Editions INSERM-John Libbey, 1993.
Jean Paul Gaudillière &I lana Löwy (eds.), The Invisible Industrialist: Manufactures and the Production of Scientific Knowledge, London: Macmillan,1998.
Delphine Gardey and Ilana Löwy (eds.), L'invention du naturel: Les sciences et la fabrication du masculin et du feminin, Paris: Archives d'Histoire Contemporaine, 2000.
Ilana Löwy and Patrick Zylberman (guest eds.), The Rockefeller Foundation and Biomedical Sciences, special issue of Studies in History and Philosophy of Biological and Biomedical Sciences, 2000.
Jean Paul Gaudillière and Ilana Löwy (eds.), Heredity and Infection: Historical Essays on the Transmission of Human Diseases, London and New York: Routledge, 2001.
Ilana Löwy and John Krige (eds.), Science, Public Health and Images of Disease: Europe, 1945–1995, Bruxelles: European Commission's Editions, 2001.
Ilana Löwy & Hélène Rouch (eds), La distinction entre sexe et genre: Une historie entre biologie et culture, Paris: L'Harmattan, 2003.
Ilana Löwy (guest ed.), Ludwik Fleck: Epistemology and Biomedical Sciences, special issue of Studies in History and Philosophy of Biological and Biomedical Sciences, 2004.
Johannes Fehr, Nathalie Jas and Ilana Lowy (eds.), Penser avec Fleck—Investigating a Life, Studying Life Sciences, Zurich: Collegium Helveticum, 2009.
Ilana Löwy (ed), Microscopic Slides: Reassessing a Neglected Historical Resource, special issue of History and Philosophy of Life Sciences, 2013: 35.
See also
Science, technology and society
History of medicine
Ludwik Fleck
Feminism
References
Science and technology studies scholars
French science writers
20th-century French anthropologists
French women anthropologists
French sociologists
French women sociologists
Polish anthropologists
Polish women anthropologists
Polish sociologists
Polish women sociologists
20th-century Polish Jews
Living people
1948 births
20th-century French women scientists
21st-century French women scientists
People from Łódź | Ilana Löwy | [
"Technology"
] | 1,217 | [
"Science and technology studies",
"Science and technology studies scholars"
] |
54,812,230 | https://en.wikipedia.org/wiki/Laser%2050 | The Laser 50 is an educational portable computer sold by Vtech that ran the BASIC programming language. It was released in 1984.
Specifications
The Laser 50 used a Zilog Z80 central processing unit running at 3.5 MHz, 2 kB to 18 kB of RAM, a 12 kB ROM, and a 80x7 dots LCD screen.
Microcomputers
Computer-related introductions in 1984 | Laser 50 | [
"Technology"
] | 80 | [
"Computing stubs"
] |
54,816,006 | https://en.wikipedia.org/wiki/Light%20curve%20%28botany%29 | In botany, a light curve shows the photosynthetic response of leaf tissue or algal communities to varying light intensities. The shape of the curve illustrates the principle of limiting factors; in low light levels, the rate of photosynthesis is limited by the concentration of chlorophyll and the efficiency of the light-dependent reactions, but in higher light levels it is limited by the efficiency of RuBisCo and the availability of carbon dioxide. The point on the curve where these two differing slopes meet is called the light saturation point and is where the light-dependent reactions are producing more ATP and NADPH than can be utilized by the light-independent reactions. Since photosynthesis is also limited by ambient carbon dioxide levels, light curves are often repeated at several different constant carbon dioxide concentrations.
References
Photosynthesis | Light curve (botany) | [
"Chemistry",
"Biology"
] | 169 | [
"Biochemistry",
"Photosynthesis",
"Chemical process stubs"
] |
54,816,867 | https://en.wikipedia.org/wiki/Christine%20Riedtmann | Christine Riedtmann (born 1952) is a Swiss mathematician specializing in abstract algebra. She earned her PhD in 1978 from the University of Zurich under the supervision of Pierre Gabriel, and is a professor emeritus (since 2016) at the University of Bern.
In 2012–2013 she was president of the Swiss Mathematical Society.
Selected publications
References
Further reading
Interview with Riedtmann in the Berner Zeitung, February 19, 2015 (in German)
1952 births
Living people
20th-century Swiss mathematicians
21st-century Swiss mathematicians
Algebraists
Swiss women mathematicians
University of Zurich alumni
Academic staff of the University of Bern | Christine Riedtmann | [
"Mathematics"
] | 122 | [
"Algebra",
"Algebraists"
] |
54,817,184 | https://en.wikipedia.org/wiki/Astomonema | Astomonema is a genus of nematode worms in the family Siphonolaimidae. They lack a mouth or conventional digestive tract, but contain symbiotic sulfur-oxidizing bacteria that serve as their primary food source. They live in the marine interstitial habitat.
Systematics
The genus was first described in 1982 from specimens collected at the coast of North Carolina. It belongs to the subfamily Astomonematinae within the family Siphonolaimidae, along with another genus Parastomonema; both these genera have reduced digestive systems and paired ovaries. Five species of Astomonema have been described.
Astomonema jenneri Ott, Rieger, Rieger & Enderes, 1982
Astomonema obscura (Boucher & Helléouët, 1977)
Astomonema otti Vidakovic & Boucher, 1987
Astomonema southwardorum Austen, Warwick & Ryan, 1993
Astomonema brevicauda (Vitiello, 1971) Vidakovik & Boucher, 1987 (taxon inquirendum)
Description
Worms of the type species Astomonema jenneri are long and slender, with a maximum body diameter of 25.5 to 30 μm, but body length between 4.6 to 16.3 mm. Astomonema and the related genus Parastomonema are distinguished from other members of the family Siphonolaimidae by their lack of a mouth, highly reduced pharynx, and modified midgut that contains prokaryotic symbionts. Features that they share with other Siphonolaimidae include the overall body shape (long, slender and cylindrical, only slightly tapered at the front), conspicuous amphidial glands, large nerve ring, lack of setae on the body, and ability to heal wounds readily when the body is injured or broken.
Symbiosis with bacteria
Although nematodes in this genus lack a conventional gut, they have a chain of long, thin, and slender cells that run down the center of the body. These cells are interpreted as a rudimentary or highly-modified gut wall, and they have few organelles besides nuclei and mitochondria. This central layer of cells contains symbiotic bacteria, which are intracellular in A. jenneri but extracellular in other species e.g. A. southwardorum. The bacteria have an elliptical shape in cross-section, and can have different sizes in different host species. For example, in A. jenneri they are 1 x 3 μm whereas in A. southwardorum they are up to 4 x 6 μm. In A. jenneri, a second type of bacteria that is smaller (0.1 - 0.5 μm) and rod-shaped has been observed, but is much less common than the larger cells.
The bacteria belong to the family Chromatiaceae in the Gammaproteobacteria, and are close relatives of similar symbionts from oligochaete worms Olavius algarvensis, Inanidrilus leukodermatus, and symbionts from the nematode subfamily Stilbonematinae (Desmodoridae). Their relatives are sulfur-oxidizing chemoautotrophs that use energy from oxidation of sulfur compounds in the environment (e.g. sulfide) to fuel the production of biomass by carbon fixation. The symbionts of Astomonema are likely to also be sulfur-oxidizers because they have at least one of the key genes, aprA, encoding the alpha subunit of adenylyl-sulfate reductase, involved in the metabolic pathway of sulfur oxidation. This is an example of chemosynthetic symbiosis, where symbiotic prokaryotes use chemical energy to produce biomass and feed their host animals, which often have highly-reduced digestive systems.
See also
Stilbonematinae – subfamily of nematodes (family Desmodoridae) that also have sulfur-oxidizing symbiotic bacteria
References
Chromadorea genera
Chemosynthetic symbiosis | Astomonema | [
"Biology"
] | 864 | [
"Biological interactions",
"Chemosynthetic symbiosis",
"Behavior",
"Symbiosis"
] |
54,817,593 | https://en.wikipedia.org/wiki/Anti%20inflammatory%20agents%20in%20breast%20milk | The anti-inflammatory components in breast milk are those bioactive substances that confer or increase the anti-inflammatory response in a breastfeeding infant.
References
Bibliography
Breastfeeding
Infant feeding
Immune system
Breast milk | Anti inflammatory agents in breast milk | [
"Biology"
] | 43 | [
"Immune system",
"Organ systems"
] |
54,819,108 | https://en.wikipedia.org/wiki/Primordial%20Inflation%20Polarization%20Explorer | Primordial Inflation Polarization Explorer (PIPER) is a high-altitude scientific balloon program designed to fly a millimeter-wave telescope for the purpose investigate the nascent stages of the universe.
The program is planned and funded by NASA's Goddard Space Flight Center, and being overseen by the astrophysicist Al Kogut.
References
Balloon-borne experiments
Balloons (aeronautics)
Goddard Space Flight Center | Primordial Inflation Polarization Explorer | [
"Astronomy"
] | 82 | [
"Outer space stubs",
"Outer space",
"Astronomy stubs"
] |
54,819,249 | https://en.wikipedia.org/wiki/Naphthol%20AS | Naphthol AS is an organic compound with the formula C10H6(OH)C(O)NHC6H5. It is the anilide of 3-hydroxy-2-carboxynaphthalene. Many analogous compounds are known, designated with a differing suffix. For example, in Naphthol AS-OL, the aryl substituent on nitrogen is C6H4-2-OCH3. These compounds are used as coupling partners in the preparation of some azo dyes.
History
In 1911, it was found to be a good precursor to dyes for wool by chemists at K. Oehler Anilin- und Anilinfarbenfabrik Offenbach.
References
Organic pigments
Azo dyes
Amides | Naphthol AS | [
"Chemistry"
] | 163 | [
"Functional groups",
"Organic compounds",
"Amides",
"Organic compound stubs",
"Organic chemistry stubs"
] |
54,819,521 | https://en.wikipedia.org/wiki/NGC%204458 | NGC 4458 is an elliptical galaxy located about 54 million light-years away in the constellation of Virgo. It was discovered by astronomer William Herschel on April 12, 1784. NGC 4458 is a member of Markarian's Chain which is part of the Virgo Cluster. It is in a pair with the galaxy NGC 4461. NGC 4458 and NGC 4461 are interacting with each other.
NGC 4458 may have a supermassive black hole with an estimated mass of 200 million Suns ( M☉).
Nuclear disk
NGC 4458 has an edge-on nuclear disk which is estimated to be about 6 billion years old. The disk likely formed from the merger of a gas-rich galaxy and has been found to have "similar properties to the decoupled cores of bright ellipticals".
Counter-rotating core
Using Hubble images, it has been determined that NGC 4458 has a counter-rotating core.
Metallicity
NGC 4458 has a low metal content but has an overabundance of the element iron.
See also
List of NGC objects (4001–5000)
Messier 86
References
External links
Elliptical galaxies
Virgo (constellation)
4458
Virgo Cluster
41095
7610
Astronomical objects discovered in 1784 | NGC 4458 | [
"Astronomy"
] | 253 | [
"Virgo (constellation)",
"Constellations"
] |
54,822,651 | https://en.wikipedia.org/wiki/Glycan%20array | Glycan arrays, like that offered by the Consortium for Functional Glycomics (CFG), National Center for Functional Glycomics (NCFG) and Z Biotech, LLC, contain carbohydrate compounds that can be screened with lectins, antibodies or cell receptors to define carbohydrate specificity and identify ligands. Glycan array screening works in much the same way as other microarray that is used for instance to study gene expression DNA microarrays or protein interaction Protein microarrays.
Glycan arrays are composed of various oligosaccharides and/or polysaccharides immobilised on a solid support in a spatially-defined arrangement. This technology provides the means of studying glycan-protein interactions in a high-throughput environment. These natural or synthetic (see carbohydrate synthesis) glycans are then incubated with any glycan-binding protein such as lectins, cell surface receptors or possibly a whole organism such as a virus. Binding is quantified using fluorescence-based detection methods. Certain types of glycan microarrays can even be re-used for multiple samples using a method called Microwave Assisted Wet-Erase.
Applications
Glycan arrays have been used to characterize previously unknown biochemical interactions. For example, photo-generated glycan arrays have been used to characterize the immunogenic properties of a tetrasaccharide found on the surface of anthrax spores. Hence, glycan array technology can be used to study the specificity of host-pathogen interactions.
Early on, glycan arrays were proven useful in determining the specificity of the Hemagglutinin (influenza) of the Influenza A virus binding to the host and distinguishing across different strains of flu (including avian from mammalian). This was shown with CFG arrays as well as customised arrays.
Cross-platform benchmarks led to highlight the effect of glycan presentation and spacing on binding.
Glycan arrays are possibly combined with other techniques such as Surface Plasmon Resonance (SPR) to refine the characterisation of glycan-binding. For example, this combination led to demonstrate the calcium-dependent heparin binding of Annexin A1 that is involved in several biological processes including inflammation, apoptosis and membrane trafficking.
References
Microarrays
Glycobiology
Glycomics
Carbohydrates | Glycan array | [
"Chemistry",
"Materials_science",
"Biology"
] | 516 | [
"Biochemistry methods",
"Biomolecules by chemical classification",
"Carbohydrates",
"Genetics techniques",
"Microtechnology",
"Microarrays",
"Organic compounds",
"Glycomics",
"Bioinformatics",
"Molecular biology techniques",
"Carbohydrate chemistry",
"Biochemistry",
"Glycobiology"
] |
54,823,918 | https://en.wikipedia.org/wiki/Gas%20venting | Gas venting, more specifically known as natural-gas venting or methane venting, is the intentional and controlled release of gases containing alkane hydrocarbons - predominately methane - into Earth's atmosphere.
It is a widely used method for disposal of unwanted gases which are produced during the extraction of coal and crude oil.
Such gases may lack value when they are not recyclable into the production process, have no export route to consumer markets, or are surplus to near-term demand.
In cases where the gases have value to the producer, substantial amounts may also be vented from the equipment used for gas collection, transport, and distribution.
Gas venting contributes strongly to climate change. Nevertheless, many individual cases are sufficiently small and dispersed to be deemed "safe" with regard to immediate health hazards.
Large and concentrated releases are usually abated with gas flares to produce relatively less-harmful carbon dioxide gas.
Gas venting and flaring that are performed as routine practices are especially wasteful and may be eliminated in many modern industrial operations, where other low-cost options are available to utilize the gas.
Gas venting is not to be confused with similar types of gas release, such as those from:
emergency pressure relief as a method of last resort to prevent equipment damage and safeguard life, or
fugitive gas emissions which are unintentional gas leaks that occur in coal, oil, and gas operations, such as from orphan wells
Gas venting should also not be confused with "gas seepage" from the earth or oceans - either natural or due to human activity.
Oil field practice relating to unwanted gas
Petroleum extraction from oil wells, where acquiring crude oil is the primary and sometimes sole financial objective, is generally accompanied by the extraction of substantial amounts of so-called associated petroleum gas (i.e. a form of raw natural gas).
Global statistics from year 2012 show that the majority (58%) of this gas was re-injected for storage and to help maintain well pressure, 27% was sent to consumption markets, and the remaining 15% was vented or flared near the well site.
100 million tons of the vented associated gas was combusted in flares worldwide, equal to about 3-4% of all gas produced from oil and gas wells. The flared gas yielded nearly 350 million tons of CO2-equivalent emissions of greenhouse gases, contributing about 1% of the 33 billion tons of carbon dioxide (CO2) released from the burning of all fossil fuels. Flare Gas Recovery Systems (FGRS) are being increasingly implemented as a more economically productive alternative to flaring.
Preferably, all of the unwanted gas would at least be abated in gas flares, but this has not been achieved in practice. For example, the vented volumes from individual wells are sometimes too small and intermittent, and may present other difficulties (e.g. high concentrations of contaminants) that make flaring more technically and economically challenging.
Also, gas will continue to effervesce from the crude oil for some time after it is moved into storage tanks at the well site and transported elsewhere. This gas may also be routed to a flare stack, utilized, or designed to escape without mitigation through vents or pressure regulators.
Global tracking estimates from the International Energy Agency (IEA) during year 2019 indicate that an additional 32 million tons of methane were vented without abatement from all petroleum extraction; including onshore conventional oil, offshore oil, unconventional oil, and downstream oil activities.
When including the amount released from incomplete gas flares and fugitive emissions, the estimated total is about 37 million tons.
Matthew Johnson, from the Energy and Emissions Research Lab (EER) at Carleton University in Ottawa, Ontario, Canada, said in a December 2023 interview thatcontrary to common beliefsventing, particularly from heavy oil facilities designed for normal operations, is the primary source of methane emissions in the oil and gas industry. Johnson stresses the urgency of swiftly retrofitting oil and gas sites, considering that the associated costs are reasonable, based on various studies. The estimated cost for retrofitting for the total industry in Canada is estimated at $3.3 billion between 2027 and 2040 for implementing both venting and flaring requirements in the . Jonson said that while fossil fuels are not going to be phased out "overnight", "when it comes to methane emissions, we have a solution and we can implement it right now." A 2023 Energy and Emissions Research Lab report discusses challenges in meeting the 2030 methane reduction targets under the Global Methane Pledge, due to uncertainties in emission levels from oil and gas operations. The research, which centers on Alberta, Canadathe Canadian province with the largest oil and gas-industrypresents a methane inventory for 2021 that exceeds the official federal inventory by 1.5 times. The study underscores that nearly two-thirds of emissionsprimarily stemming from uncontrolled tanks, pneumatics, and unlit flares, result from gas ventingindicating substantial opportunities for mitigation. Notably, methane intensities in Alberta are four times higher than those in neighboring British Columbia, highlighting the necessity for independent monitoring and reporting ensuring the success of emission reduction initiatives. Gas venting in the oil and gas industry has gained attention in Alberta, Canada, particularly in light of proposed legislative changes aimed at reducing methane emissions. Federal Environment Minister Steven Guilbeault presented a plan during the 2023 United Nations Climate Change Conference in Dubai, outlining a national cap-and-trade system to curb emissions without hindering production. The proposed framework aims to cap 2030 emissions at 35 to 38 percent below 2019 levels, aligning with the federal government's objective of achieving net-zero carbon emissions in the sector by 2050. Given that the oil and gas industry contributes to 28 percent of Canada's emissions, these proposed changes signal a significant effort to address environmental concerns and combat climate change.
Coal mining and coalbed methane activity
Substantial amounts of methane-rich gas are trapped and adsorbed within coal formations, and are unavoidably desorbed in association with coal mining.
In some cases of sub-surface mining, a formation is permeated with boreholes prior to and/or during extraction work, and the so-called firedamp gases allowed to vent as a safety measure.
Also during work, methane enters the ventilation air system at concentrations as high as 1%, and is usually freely exhausted from the mine opening.
Such ventilation air methane (VAM) is the largest source of methane from all operating and decommissioned coal mines worldwide.
Substantial methane also continues to desorb from coal placed into storage and from abandoned mines.
The U.S. Environmental Protection Agency projects that by year 2020, global methane releases from coal mines throughout the world will exceed 35 million tons or 800 million tons of CO2-equivalent emissions, and account for 9% of all global methane emissions. China contributes over 50% of the total, followed by the United States (10%) and Russia (7%), and then by Australia, Ukraine, Kazakhstan, and India (3-4% each). About 200 mines across a broad scope of countries had implemented technology by the year 2015 to capture about 3 million tons of methane, either for economic use or for abatement in gas flares or thermal oxidizers.
Outcroppings, seams, or formations near the surface are also sometimes permeated with wells to extract and capture the methane, in which event it is classified as a form of unconventional gas.
Such coalbed methane capture can reduce the volume of gas seepage that would otherwise occur naturally, while in-turn adding emissions of carbon dioxide once the fuel is utilized elsewhere.
Global tracking estimates from the IEA during 2019 suggest that about 40 million tons of methane were released from all activities related to coal mining. This total amount includes all vented, fugitive and seepage emissions.
Gas field and gas pipeline practices
In gas fields, acquiring non-associated petroleum gas (i.e. another form of raw natural gas) is the primary financial objective, and very little is unwanted compared to the gas produced in oil fields or coal mines.
The majority of venting emissions instead occur during the pipeline transport to trading & distribution hubs, refineries, and consumer markets.
The U.S. Department of Energy reports that a majority of the venting within U.S. gas industry operations in year 2017 occurred at compressor stations and from pneumatically operated controllers and regulators.
Improved maintenance strategies and advanced equipment technologies either exist or are being developed to reduce such venting.
Global tracking estimates from the IEA during year 2019 further indicate that about 23 million tons of methane were vented from all gas industry segments, including onshore conventional gas, offshore gas, unconventional gas, and downstream gas activities.
When including the amount released from fugitive emissions, the estimated total is about 43 million tons.
Historical context
Associated petroleum and coal mining gases were sometimes considered troublesome, dangerous, low value: a "free" by-product associated with financially more lucrative coal or liquid hydrocarbon recovery that had to be dealt with. The growth of international gas markets, infrastructure and supply chains have done much to change this. It is also becoming more of a standard practice to:
capture and use associated gas to provide local power, and to
reinject re-compressed gas for oil reservoir pressure maintenance, secondary recovery, and potential later reservoir depressurization once hydrocarbon liquids recovery has been maximized and a gas export infrastructure and market access have been established.
Today, it is financially viable to develop even relatively small hydrocarbon reservoirs containing non-associated gas (i.e. with little or no oil) close to a market or export route, as well as large, remote accumulations.
Fossil gas was recently promoted by some industry advocates and policy makers as a "bridge fuel" that could yield the least waste, and thus environmental damage and accompanying economic losses, during the transition from finite fossil-fuel reserves to more sustainable sources. However, the actual volumes of methane released cumulatively over the supply chain have a near-term climate warming impact which already rivals, and may grow to exceed, that from using coal and oil.
Environmental impact
Venting and other releases of gaseous hydrocarbons have increased steadily throughout the industrial age alongside the rapid growth in production and consumption of fossil fuels.
The International Energy Agency estimates that total annual methane emissions from the oil and gas industry alone rose from about 63 to 82 million tons over years 2000 thru 2019; an average increase of about 1.4% per year.
Globally, the IEA estimates that the geologic extraction of coal, crude oil, and natural gas is responsible for 20% of all methane emissions. Other researchers have found evidence that their contribution may be substantially higher; 30% or greater.
Methane's atmospheric concentration has nearly doubled over the last century, and is already a factor 2.5 greater than at any point in the last 800,000 years.
Methane is a potent warming gas despite its lower abundance compared to atmospheric carbon dioxide. Atmospheric methane is responsible for at least one-quarter and as much as one-third of the changes in radiative forcing that drive near-term climate warming.
The ethane, propane, and butane components of natural gas have much shorter atmospheric lifetimes (ranging from about 1 week to 2 months) compared to methane (1-2 decades) and carbon dioxide (1-2 centuries). They consequently do not become well-mixed into the atmosphere and have much lower atmospheric abundances. Nevertheless, their oxidation ultimately leads to the creation of longer-lived carbon compounds that also disturb the atmosphere and the planetary carbon cycle through a variety of complex pathways.
See also
Routine flaring
Methane emissions
References
External links
Flare and Vent Disposal Systems on PetroWiki
Coalbed Methane on PetroWiki
Natural gas
Methane | Gas venting | [
"Chemistry"
] | 2,420 | [
"Greenhouse gases",
"Methane"
] |
54,825,378 | https://en.wikipedia.org/wiki/National%20Center%20for%20Theoretical%20Sciences%2C%20Physics | National Center for Theoretical Sciences (NCTS) in Taiwan was established on August 1, 1997 and fully funded by the National Science Council (NSC), which is reorganized and became Ministry of Science and Technology (Taiwan) (MoST) in 2014, with strong endorsement from some of the most eminent scholars, including Yang Chen-Ning and Shing-Tung Yau. It is a national research center with the goal to contribute to the advancement of frontier research, and to promote interdisciplinary and international research cooperation in theoretical sciences.
NCTS was set up with a center in Theoretical Physics and one in Mathematics. For the first 18 years, NCTS was located on the campus of the National Tsing Hua University, Hsinchu. Since 2015, NCTS Mathematics has been relocated to the National Taiwan University, Taipei. NCTS Physics and NCTS Mathematics operate mostly independently to serve their separate communities and cooperate on some of their national programs and strategies. Tung-Mow Yan was the founder director of NCTS.
Previous directors of the Physics Division were Tung-Mow Yan, Ting-Kuo Lee, Darwin Chang, Tu-Nan Chang, Hsiang-Nan Li, Chung-Yu Mou, Ling-Fong Li, Xiao-Gang He, and Chong-Sun Chu. The current director is Guang-Yu Guo.
Mission
NCTS Physics aims to act as a national multidisciplinary facility and platform envision to contribute to the advancement of frontier research in physics. Its academic programs and activities are operated with the goals: to act as an effective platform to stimulate and to enhance the interaction and collaboration among researchers; to empower talented students and postdoctoral researchers to make significant contributions in the frontier of research subjects; to serve as an efficacious channel to network the home researchers with other scholars and preeminent institutions abroad; and to explore new frontiers in physics research and innovation, and to enhance the extent and breadth of interdisciplinary researches as well as the collaboration with scientists in the experimental fields.
Research
Scientists at NCTS work on the following major research subjects and research topics:
High Energy Phenomenology, String and Gravity: dark matter, dark energy, nature of electroweak symmetry breaking, neutrino physics, collider physics, holographic and quantum informatic property of gravity, scattering amplitudes, inflationary cosmology, quantum geometry and branes, exact results in QFT.
Condensed Matter Physics: first principle calculations of new quantum materials, topological materials, spintronics, strongly correlated system, DMRG and tensor network, emergent symmetry, quantum transport.
Atomic, Molecular and Optical Physics: many-body dynamics of ultracold atoms, long-range effects, light-atom interaction and quantum control, quantum steering and quantum information.
Soft Matters, Bio-Physics and Complex Systems: complex and biological network, complex dynamics and chaos, nonequilibrium statistical physics of driven/active soft matter, interplay of proliferation, utilization and feedback regulations in complex interacting system.
Programs
NCTS operates a number of academic programs in order to engage researchers in creative scientific activities. Interdisciplinary interactions are encouraged. Programs include the NCTS Topic Programs whose purpose is to encourage collaboration and to foster the generation of new ideas and initiatives for breakthrough; Rapid Response Workshop whose purpose is to respond actively and quickly to any sudden development of the field which has a significant potential of impact; NCTS Distinguished Lecturer whose objective is to bring distinguished scholars to NCTS to give a lecture or lecture series on a specific topic of research or a topic of general interest. In addition, we have an active visitor program with both international and domestic scientists.
NCTS scientists are also involved in advancing a number of Thematic Research, Interdisciplinary Research and Experimental Collaboration Group: these are focused research groups formed by a team of active home researchers with complementary expertise, with the primary goal of solving some of the outstanding problems of the subject, or to engage in rigorous interaction in order to foster collaboration across conventional boundaries and traditionally defined disciplines. These groups have been the breeding ground for a number of young brilliant PhD students and postdoctoral researchers who have gone on for a successful career in physics.
Some of the representative programs
NCTS Annual Theory Meeting on Particles, Strings and Cosmology, Dec 9-12, 2015
Forum on Future of High Energy Physics,Dec 11, 2015
Israel-Taiwan Workshop on Quantum Optics, Quantum Electronics, and Quantum Matters, Dec 14-15, 2015
NCTS Annual Theory Meeting 2015: Condensed Matter Physics, Dec 16-19
Japan-Taiwan workshop on KAGRA, Dec 23, 2015
The 1st KEK-KIAS-NCTS Joint Workshop on Particle Physics Phenomenology, May 26-28, 2016
Public lecture by Prof. Jerome Friedman (1990 Nobel laureate in Physics), July 12, 2016
The 13th Taiwan International Symposium on Statistical Physics and Complex Systems (StatPhys-Taiwan-2016), Sep 6-8, 2016
The 19th Asian Workshop on First-Principles: Electronic Structure Calculations (ASIAN-19), Oct 31-Nov 2, 2016
9th Taiwan String Workshop, Nov 11-13, 2016
NCTS distinguished lecture, Nov 22-24,2016
NCTS Annual Theory Meeting 2016: Particles,Cosmology and String, Dec 06-09, 2016
NCTS Annual Theory Meeting 2016: Quantum Simulations and Numerical Studies in Many Bodies Physics, Dec 09-11, 2016
UNESCO talk on CERN, Apr 19, 2017
Searching for – and finding! Gravitational waves, May 24,2017
Public talks by Prof. Shing-Tung Yau and Prof.Takaaki Kajita, Aug 2, 2017
Symposium on Frontiers in Physics, Aug 3, 2017
References
Physics research institutes
Theoretical physics institutes | National Center for Theoretical Sciences, Physics | [
"Physics"
] | 1,151 | [
"Theoretical physics",
"Theoretical physics institutes"
] |
54,825,381 | https://en.wikipedia.org/wiki/3-Hydroxy-2-naphthoic%20acid | 3-Hydroxy-2-naphthoic acid is an organic compound with the formula C10H6(OH)(CO2H). It is one of the several hydroxynaphthoic acids. It is a precursor to some azo dyes and pigments. It is prepared by carboxylation of 2-naphthol by the Kolbe–Schmitt reaction.
Reactions
3-Hydroxy-2-naphthoic acid is a precursor to many anilides, such as Naphthol AS, which are reactive toward diazonium salts to give deeply colored azo compounds. Azo coupling of 3-hydroxy-2-naphthoic acid gives many dyes as well. Heating 3-hydroxy-2-naphthoic acid in ammonia give 3-amino-2-naphthoic acid.
Related compounds
2-Hydroxy-1-naphthoic acid
References
2-Naphthols
Naphthoic acids
Alpha hydroxy acids | 3-Hydroxy-2-naphthoic acid | [
"Chemistry"
] | 213 | [
"Organic compounds",
"Organic compound stubs",
"Organic chemistry stubs"
] |
54,825,621 | https://en.wikipedia.org/wiki/Oracle%20Cloud%20Enterprise%20Resource%20Planning | Oracle Cloud Enterprise Resource Planning is a cloud-based ERP software application suite introduced by Oracle Corporation in 2012. Oracle ERP Cloud manages enterprise functions including accounting, financial management, project management, and procurement.
Product
Oracle Cloud ERP is an end-to-end Software as a service suite that manages enterprise operations. The suite runs on an Oracle technology stack in Oracle's cloud centers. Oracle Cloud ERP is accessible through both public and private cloud implementation and supports hybrid deployment. Oracle supplies updates to Oracle ERP Cloud at least twice annually. According to the company's website, there are nine different software modules that make up the Oracle Cloud ERP suite, namely:
Financials
Accounting Hub
Procurement
Project Management
Risk Management
Enterprise Performance Management (EPM)
AI Apps for ERP
Supply Chain Management (SCM)
NetSuite
The software suite is designed to support international enterprise functions and includes multi-GAAP, multi-currency, multi-language, and multi-subsidiary capabilities.
History
Oracle Cloud ERP was based originally on Oracle Fusion Applications, Oracle's enterprise resource planning software suite developed for Oracle Fusion Architecture and Oracle Fusion Middleware released in 2011. In June 2012, Oracle CTO and chairman of the board Larry Ellison announced the Oracle Cloud ERP application suite as a part of Oracle Cloud, the company's broad set of cloud-based applications. Oracle announced preview availability of Oracle Cloud ERP at Oracle OpenWorld 2012. In October 2015, the company reported that Oracle ERP Cloud had surpassed 1,300 customers. On August 2, 2017, Oracle announced Release 13 of Oracle Cloud ERP.
In 2017, Oracle CEO Safra Catz announced the availability of Oracle Cloud ERP in India to assist the country in preparation of its Goods and Services tax reforms.
In March 2017, Oracle reported that Oracle Cloud ERP had grown 280% in fiscal quarter 3.
In September 2017, it was reported Oracle's cloud ERP business grew 156% in first quarter 2017–18 and had reached an annual run rate of $1.2 billion.
Regions
Oracle ERP Cloud is available in North America, South America, Asia and EMEA regions.
Certifications
Oracle offers certifications in Software as a Service (SaaS) specializations for Oracle ERP Cloud.
Oracle Financials Cloud
Oracle Accounting Hub Cloud 2017 Certified Implementation Specialist
Oracle Financials Cloud: General Ledger 2017 Certified Implementation Specialist
Oracle Financials Cloud: Payables 2017 Certified Implementation Specialist
Oracle Financials Cloud: Receivables 2017 Certified Implementation Specialist
Oracle Revenue Management Cloud Service 2017 Certified Implementation Specialist
Oracle Procurement Cloud
Oracle Procurement Cloud 2017 Certified Implementation Specialist
Oracle Project Portfolio Management Cloud
Oracle Project Portfolio Management Cloud 2017 Certified Implementation Specialist
Oracle Risk Management Cloud
Oracle Financial Reporting Compliance Cloud 2017 Certified Implementation Specialist
Notable customers & partnerships
Bank of America
Thomson Reuters
Qantas
Blue Shield of California
Office for National Statistics
Hearst
Wake Forest Baptist Medical Center
Health Care Service Corporation
Carbon
HM Treasury
PrimeQ
Caesar Entertainment
Academic institutions
The College of New Jersey
Shawnee State University
Birmingham City University
University of Wyoming
Boise State University
University of Kansas
Vanderbilt University
San Bernardino Community College
Events
Oracle OpenWorld
Oracle OpenWorld is an annual technology conference hosted by Oracle and has featured announcements of updates to Oracle ERP Cloud.
COLLABORATE
COLLABORATE is an annual technology forum hosted by independent Oracle users groups, including the International Oracle Users Group (IOUG), the Oracle Applications Users Group (OAUG), and Quest Oracle Community, that provides training for Oracle products including Oracle ERP Cloud.
See also
Enterprise software
References
External links
Accounting software
Project management software
ERP software
Oracle software
Internet properties established in 2012
Cloud applications
Cloud platforms
Enterprise software
Business software
Human resource management software
Customer relationship management software
2012 software | Oracle Cloud Enterprise Resource Planning | [
"Technology"
] | 738 | [
"Cloud platforms",
"Computing platforms"
] |
53,535,975 | https://en.wikipedia.org/wiki/Bloomsbury%20Dispensary%20for%20the%20Relief%20of%20the%20Sick%20Poor | The Bloomsbury Dispensary for the Relief of the Sick Poor was an institution founded in 1801 to provide medical aid and suitable nourishment to the poor people of that part of London.
George Pinckard founded the dispensary on 26 October 1801 and became its first physician, remaining there for thirty years. It was established at 62 Great Russell Street.
References
Charities based in London
19th century in London
Pharmacy
Bloomsbury
1801 establishments in England | Bloomsbury Dispensary for the Relief of the Sick Poor | [
"Chemistry"
] | 93 | [
"Pharmacology",
"Pharmacy"
] |
53,536,822 | https://en.wikipedia.org/wiki/NGC%20425 | NGC 425 is a spiral galaxy in the constellation of Andromeda. It was discovered on 29 October 1866 by Truman Safford.
References
External links
Andromeda (constellation)
Astronomical objects discovered in 1866
Discoveries by Truman Safford
0425
Spiral galaxies
004379
000758 | NGC 425 | [
"Astronomy"
] | 60 | [
"Andromeda (constellation)",
"Constellations"
] |
53,537,338 | https://en.wikipedia.org/wiki/NGC%20426 | NGC 426 is an elliptical galaxy that is also classified as a Seyfert galaxy. It is located in the constellation of Cetus, and it was discovered on December 20, 1786, by William Herschel.
References
External links
0426
Cetus
Elliptical galaxies
Seyfert galaxies
Astronomical objects discovered in 1786
004363 | NGC 426 | [
"Astronomy"
] | 69 | [
"Cetus",
"Constellations"
] |
53,537,551 | https://en.wikipedia.org/wiki/Albert%20Fredrick%20Ottomar%20Germann | Albert Fredrick Ottomar Germann (February 18, 1886 – December 22, 1976) was an American physical chemist, university professor, and chemical entrepreneur.
Early life and education
Germann was born in Peru, Miami County, Indiana, eldest child of Mary Fredericke Mueller (1864–1942) and Gustave Adolph Germann (1860–1940). His only sibling was Frank Erhart Emmanuel Germann (1887–1974), who also became a physical chemist. Albert Germann graduated from Peru High School in 1904. Germann taught in Miami County rural schools while working his way through a chemistry major at Indiana University Bloomington. He received the A.B. in chemistry in 1909 and the A.M. in chemistry in 1910, both from Indiana University, and the M.Sc. degree in chemistry from the University of Wisconsin in Madison, also in 1910. He received the Sc.D. degree (doctorat ès sciences physiques et chimiques) from the University of Geneva (Geneva, Switzerland) in 1914 under the guidance of Philippe-Auguste Guye (1862–1922).
Career and research
Germann's first scholarly publications reported his undergraduate electrochemistry research under the direction of Frank Curry Mathers (1881–1973). His M.Sc. research at Wisconsin was with Joseph Howard Mathews (1881–1970). His Sc.D. thesis was published as Albert-F.-O. Germann, Révision de la densité de l'oxygène, contribution à la détermination de la densité l'air à Genève, thèse number 514 (Genève: Imprimerie Albert Κündig, 1913, 63 pages); Journal de Chimie physique, volume 12 (1914), pages 66–108.
Germann was on the chemistry faculties of Western Reserve University, Cleveland, Ohio (1913–1921), Stanford University, Palo Alto, California (1921–1925), and Valparaiso University, Valparaiso, Indiana (1926–1927).
At Western Reserve, he extended his doctoral research, and then began cryoscopic studies of non-aqueous systems involving boron trifluoride or phosgene. Five students conducted these experiments. Harold Simmons Booth (1891–1953) had already completed his doctoral program at Cornell University. In September 1920, Booth became a member of the Western Reserve chemistry faculty, and was to have a distinguished career as an inorganic chemist at Western Reserve. He served as department chair. He was Editor-in-Chief of the inaugural volume (in 1939) of Inorganic Syntheses, a prestigious series that continues. He was promoted to Hurlbut Professor of Chemistry in 1947. Vernon Jersey (1898–1984) had received the A.B. in chemistry from Western Reserve in 1920, and had begun graduate research with Germann on phosgene. He studied solutions of phosgene and chlorine, obtaining cryoscopic evidence for ten different compounds, including chlorine octaphosgenate. Jersey's interests evolved into biochemistry, and he earned a Ph.D. in 1935 from Western Reserve. He then joined with Germann to form Nutritional Research Associates, Inc. Wendell Phillips was beginning his senior year, and would be awarded the A.B. degree in 1921. Leland Roy Smith had received the A.B. degree in 1920, and was beginning graduate studies at Western Reserve; he received the A.M. in 1921, and received the A.M. degree from Harvard University in 1923. Marion Cleaveland (1898–1975) had received the B.A. in chemistry in 1920, and would be awarded the M.A. in 1921. She pursued doctoral studies at Columbia University from 1926 to 1928, receiving the Ph.D. Except for her time at Columbia, she taught at Western Reserve from 1921 to 1946.
At Stanford, Germann focused on phosgene as a liquid solvent. His goal was to develop a solvent-system definition of acids and bases that would apply to compounds dissolved in solvents such as phosgene.
In 1925, Germann became research director of Laboratory Products Company. Brothers William Otto Frohring (1893–1959) and Paul R. Frohring (1903–1998) "did groundbreaking laboratory work at the Laboratory Products Co. in Cleveland that produced the first ready-prepared infant formula." Recognizing that the infant-food field was becoming crowded, the Frohring brothers began to diversify research and operations. Germann was recruited to lead the company into specialty biochemicals.
Germann was granted a year leave to take an active role in Lutheranizing a faltering Valparaiso University. He became professor of chemistry at Valparaiso, head of the department of chemistry, and acting dean of the school of pharmacy. Germann was acting president of Valparaiso University from May to September, 1927. During that time, the school of pharmacy was accepted as a member of the American Association of Colleges of Pharmacy, and judged to be conforming to the Association's standards.
Back in Cleveland at Laboratory Products Company, Germann assembled his own research group. The specialty biochemical carotene was prominent in his plans. His associates were Vernon Jersey, Robert John Cross (1884–1955), Otto Ungnade (1883–1963), and Harold Barnett (1903–1956). They intended to capitalize on the vitamin revolution. Germann, Jersey, Cross, and Ungnade founded Nutritional Research Associates, Inc. in 1935 with Albert Germann President. They established research and production facilities in South Whitley, Indiana, for extraction, purification, and stabilization of Vitamin A from carrots and Vitamin E from wheat germ.
Personal life
Germann married Ida Helene Johanna Meinke (1884–1976) on November 26, 1914. They had four children: Luise Barbara Germann Pook (February 11, 1916 – January 27, 2012), Edith Germann Osborn (September 6, 1917 – March 31, 1990), Lucia May Germann Harley (May 28, 1920 – January 12, 1998), and Albert Fredrick Ottomar Germann II (born January 4, 1929).
Albert Sr. was raised as a member of the Lutheran Church (Missouri Synod) and as a youngster attended the Lutheran St. John's Christian Day School in Peru. After moving to South Whitley, Ida and Albert joined St. John's Lutheran Church (Missouri Synod), six miles east of South Whitley. Both were buried in the St. John's cemetery.
References
Further reading
Bodurtha, Arthur L., ed., (1914). History of Miami County Indiana: A Narrative Account of Its Historical Progress, Its People and Its Principal Interests (Chicago: Lewis Publishing Company), volume II, pages 456.
Fleck, George (2016). Parallel Lives: Two Hoosier Chemists from Peru, The Impress Group, Williamsburg, MA. .
Obituary, "Barbara Pook", South Whitley [Indiana] Tribune-News, February 8, 2012.
"Germann, Albert F(rederick) O(ttomar)", Who's Who in Illinois: A Biographical Dictionary of Leading Men and Women of the Commonwealth (Chicago: Larkin, Roosevelt & Larkin, Ltd., 1947), volume 1, pages 42–43.
1886 births
1976 deaths
20th-century American chemists
People from Peru, Indiana
Physical chemists
University of Geneva alumni
Indiana University Bloomington alumni
University of Wisconsin–Madison College of Letters and Science alumni
University of Wisconsin–Madison faculty
American food chemists | Albert Fredrick Ottomar Germann | [
"Chemistry"
] | 1,551 | [
"Physical chemists",
"Food chemists",
"American food chemists"
] |
53,537,603 | https://en.wikipedia.org/wiki/Compulsion%20loop | A compulsion loop, reward loop or core loop is a habitual chain of activities that a user may feel compelled to repeat. Typically, this loop is designed to create a neurochemical reward in the user such as the release of dopamine.
Compulsion loops are deliberately used in video game design as an extrinsic motivation for players, but may also result from other activities that create such loops, intentionally or not, such as gambling addiction and Internet addiction disorder.
Basis
The understanding of the motivations of compulsion loops came out of experiments performed on laboratory animals in operant conditioning chamber or a "Skinner box", where the animals are given both positive and negative stimuli for performing certain actions, such as providing food by pressing a lever. Besides demonstrating that animals would prefer positive rewards and thus learned to trigger the correct lever, B. F. Skinner found that the effects of random rewards and variable time between awards also became a factor towards how quickly the animals learned the rules of the positive reinforcement system. Ongoing research has shown that dopamine, synthesized in the animal brain, is a key neurotransmitter involved in this process; disabling the ability for receptors to react to dopamine in animal studies can impact how rapidly the animals can be conditioned.
Applying these principles to gaming, a compulsion loop creates a three-part cycle: the anticipation of receiving some reward, the activity that must be completed to receive that reward, and the act of finally obtaining the reward. From a neuroscience aspect, it is believed that the anticipation phase is where dopamine is created by the human brain, while it is released upon obtaining the reward. Dopamine creates feelings of pleasure in the brain and drives motivation, and while the neurotransmitter itself is not addictive, can lead to addictive behavior as the user desires to experience the further dopamine release.
In game design
A core or compulsion loop is any repetitive gameplay cycle that is designed to keep the player engaged with the game. Players perform an action, are rewarded, another possibility opens and the cycle repeats. A compulsion loop may be distinguished further from a core loop; while many games have a core loop of activities that a player may repeat over and over again, such as combat within a role-playing game, a compulsion loop is particularly designed to guide the player into anticipation for the potential reward from specific activities. The compulsion loop can be strengthened by adding a variable ratio schedule, where each response has a chance of producing a reward. Another strategy is an avoidance schedule, where the players work to postpone a negative consequence. Without a lack of meaningful reward, the player may eventually no longer engage with the game, causing extinction of the player population for a game. Particularly for freemium titles, where players can opt to spend real-world money for in-game boosts, extinction is undesirable so the game is designed around a near-perpetual compulsion loop alongside frequent addition of new content.
Compulsion loops in video games can be established through several means. One common approach is to show the player a "baseline" for how powerful the player-character could become, such as starting the game in an advanced power state and shortly stripping the character of those advancements and having the player rebuild the character to that state, or to show them a powerful non-player character that their starting character could eventually build towards. Another approach is through the difficulty curve of the game, making enemies stronger as the player-characters advance deeper into the game, and requiring the player to spend time to improve the character whether through new gear, abilities, or the player's own performance to progress. In multiplayer games, players may also be simply driven by envy towards other players that have more powerful characters. Some loops can rely on the concept of withdrawal, in that the player may get to a state in the game they are content with, but by some means, the game shows the player a potential of where they could be by improving, and anticipating the player to feel like they are lacking something and will return to engage in the game.
A well-known example of a compulsion loop in video games is the Monster Hunter series by Capcom. Players take the role of a monster hunter, using a variety of weapons and armor to slay or trap the creatures. By doing so, they gain monster parts and other loot that can be used to craft new weapons and equipment that is typically stronger than their previous gear. The loop presents itself that players use their current equipment to hunt monsters with a given difficulty level that provide parts that can be used to craft improved equipment. This then lets them face more difficult monsters that provide parts for even better gear. This is aided by the random nature of the drops (a variable ratio), sometimes requiring players to repeat quests several times to get the right parts. A compulsion loop may involve two or different gameplay modes that feed each other. For example, in Cult of the Lamb, one half of the game is a roguelike hack-n-slash system which the player can use to gather resources, which are then used in the game's other half, a settlement management simulation. By advancing the settlement, the player can unlock more powerful weapons and abilities in the hack-and-slash and reach more difficult areas required to obtain rarer resources needed for further settlement advancement.
Another type of compulsion loop are offered through many games in the form of a loot box or similar term, depending on the game. Loot boxes are earned progressively by continuing to play the game; this may be as a reward for winning a match, purchasable through in-game currency that one earns in game, or through microtransactions with real-world funds. Loot boxes contain a fixed number of randomly chosen in-game items, with at least one guaranteed to be of a higher rarity than the others. For many games, these items are simply customization options for the player's avatar that has no direct impact on gameplay, but they may also include gameplay-related items, or additional in-game currency. Loot boxes work under the psychology principle of variable rate reinforcement, which causes dopamine production at higher rates due to the unpredictable nature of the reward in contrast to fixed rewards. In many games, opening a loot box is accompanied by visuals and audios to heighten the excitement and further this response. Overall, a loot box system can encourage the player to continue to play the game, and potentially spend real-world funds to gain loot boxes immediately. Controversy arose in 2018 around loot boxes with several experts, governments, and concerned citizens fearing that loot boxes could lead to gambling, particularly in youth, and some governments took step to ban loot box practices that involved real-world funds.
Compulsion loops can be used as a replacement for game content, especially in grinding and freemium game experience models. The opposite of rewarding predictable, tedious and repetitive tasks are reward action contingency based systems, where players overcome game challenges with clear signals of progress.
Psychological effects
Encouraging players to return to the game world can lead to video game addiction if not careful. Internet addiction disorder can also result from a compulsion loop created by users in checking email, websites, and social media to see the results of their actions. A common concern related to compulsion loops in video games is a potential for violent video games to lead to violent behavior even though the American Psychological Association (APA) had asserted in 2019 that there is no direct connection between violent video games and real-world violent behavior, some still fear that compulsion loops in these types of games can help to reinforce violence tendencies.
References
Behaviorism
Video game terminology | Compulsion loop | [
"Technology",
"Biology"
] | 1,557 | [
"Computing terminology",
"Video game terminology",
"Behavior",
"Behaviorism"
] |
53,537,785 | https://en.wikipedia.org/wiki/Edmund%20Storms | Edmund Storms is a nuclear chemist known for his work in cold fusion.
Career
He is a nuclear chemist who worked at Los Alamos National Lab for more than 30 years. He established Kiva Labs in Santa Fe where he continues exploration of evidence of his model of cold fusion. Storms is also a Science Advisor to Cold Fusion Now.
Storm's work is listed in the Atomic Energy of Canada Ltd. 2013 Report on cold fusion, which identifies 25 theories on the mechanisms behind cold fusion, but notes that "What was apparent from this review is that there has been a plethora of investigations and theories for CF/LENR/CMNS over the last 20 years, but a relative shortage of credible, peer-reviewed information sources."
Publications
Storms has published more than a hundred journal articles and several books. He has spoken on his work at conferences of the ACS, APS, and ICCF
Selected publications
Storms, E. (2007). Science Of Low Energy Nuclear Reaction, The: A Comprehensive Compilation Of Evidence And Explanations About Cold Fusion. Singapore: World Scientific Publishing Company.
References
21st-century American chemists
Living people
1948 births
People from Camp Hill, Pennsylvania
Nuclear chemists
20th-century American chemists | Edmund Storms | [
"Chemistry"
] | 246 | [
"Nuclear chemists"
] |
53,537,827 | https://en.wikipedia.org/wiki/Theta1%20Orionis%20E | {{DISPLAYTITLE:Theta1 Orionis E}}
θ1 Orionis E (Latinised as Theta1 Orionis E) is a double-lined spectroscopic binary located 4' north of θ1 Orionis A in the Trapezium Cluster. The two components are almost identical pre-main-sequence stars in a close circular orbit, and they show shallow eclipses that produce brightness variations of a few tenths of a magnitude.
Each component of the binary system is slightly under . Although they have a subgiant spectral classification, they are still contracting onto the main sequence and are estimated to be only about 500 million years old. It is estimated that they will reach the main sequence as smaller hotter late-B stars.
The variability was first reported in 1954 and confirmed as an eclipsing binary in 2012. It has not been assigned a variable star designation but is listed in the New Catalogue of Suspected Variable Stars.
References
Orion (constellation)
G-type subgiants
5
J05351577-0523100
Orionis, Theta1E
Orionis, 41 E | Theta1 Orionis E | [
"Astronomy"
] | 223 | [
"Constellations",
"Orion (constellation)"
] |
53,537,966 | https://en.wikipedia.org/wiki/Chemirocha | "Chemirocha" is a series of three field recordings made in 1950 by ethnomusicologist Hugh Tracey during his visit to the Kipsigis people of the Great Rift Valley of Kenya. The tribe had previously heard the recordings of American country singer Jimmie Rodgers, which they integrated to their musical culture.
In 2014, the International Library of African Music returned to Kapkatet, the town where the songs were recorded, to present the digitized version of them to the locals.
Recording
During World War II, English Christian missionaries visited the Kipsigis tribe of the Great Rift Valley of Kenya. The missionaries took with them a wind-up gramophone and recordings of American singer Jimmie Rodgers. In 1950, ethnomusicologist Hugh Tracey moved to the region as he continued to help his brother working on a tobacco farm. On the side, Tracey travelled with a reel-to-reel device and he made field recordings of traditional African songs.
In the town of Kapkatet, district chief Arapsang organized the singers for Tracey to record three different songs that he would later entitle "Chemirocha I", "Chemirocha II" and "Chemirocha III". "Chemirocha III" was sung by young girls with high-pitched voices as they danced, and it was accompanied by a stringed instrument called a kibugandet. "Chemirocha" was the pronunciation that the tribe used to refer to Jimmie Rodgers, who they considered to be a half man, half antelope faun. The lyrics described that the songs performed by the being caused a level of happiness on the villagers that would "make their clothes fall off". The song was credited to "Chemutoi Ketienya with Kipsigis girls". Meanwhile, "Chemirocha I" and "Chemirocha II" were sung by men and they expressed the Kipsigis' love for their locale and their lament for it being taken by colonization. The term "Chemirocha" was, among other things, used to describe something strange and new. Tracey misinterpreted the meaning of Rodgers' music to the Kipsigis as a cargo cult, as he described Rodgers as "the spirit to whom young Kipsigi maidens appeal as they sing their song, Chemirocha, and seductively invite him to dance with them".
Release
In 1954, Tracey created the International Library of African Music to preserve the 40,000 recordings he made during his trips to several tribes. "Chemirocha III" was released by Tracey on his 1972 album The Music of Africa: Musical Instruments 1: Strings. After Tracey's death in 1977, his son Andrew Tracey took over the role of president until 2005. Diane Thram then succeeded Tracey's son as the curator of the collection. Thram started a project to digitize the recordings, and she turned to the label Ketebul Music to take the results to the villages in which they had been recorded. In 2015, the team was able to find Cheriyot Arap Kuri, an original singer in "Chemirocha I", who declared that at the time he did not know what Tracey was doing while recording and that the tribe sang to entertain him. Interpretations offered by the villagers of the word "Chemirocha" included it being "slow, nice music", as well as "Jimmie" being used to refer to a "tough guy". As for the mention of Rodgers as a faun, the son of chief Arapsang, Josiah, offered as an explanation that the mistreatment of the Kipsigis by the colonial government made the tribe consider them "man-eaters".
Footnotes
References
External links
African folk songs
Music of Kenya
Field recording
1950 songs | Chemirocha | [
"Engineering"
] | 794 | [
"Audio engineering",
"Field recording"
] |
53,542,326 | https://en.wikipedia.org/wiki/List%20of%20plant%20hybrids | This is a list of plant hybrids created intentionally or by chance and exploited commercially in agriculture or horticulture. The hybridization event mechanism is documented where known, along with the authorities who described it.
Hybrids
References
External links
Hybrids
Hybrids, list
Hybrids, list | List of plant hybrids | [
"Chemistry",
"Biology"
] | 53 | [
"Lists of plants",
"Plants",
"Hybrid organisms",
"Lists of biota",
"Hybrid plants",
"Molecular biology",
"Plant breeding"
] |
53,542,418 | https://en.wikipedia.org/wiki/UGC%2012591 | UGC 12591 is a spiral galaxy in the constellation Pegasus. It is located approximately 400 million light-years from Earth. It is the spiral galaxy with the highest known rotational speed of about 500 km/s, almost twice that of our galaxy, the Milky Way. The high rotational speed means the galaxy must be very massive at the center; the galaxy has a mass estimated at 4 times that of the Milky Way.
UGC 12591 is relatively isolated; the nearest galaxy to it is 3.55 million light-years (1.09 Mpc) away. However, its morphology suggests a merger or accretion event in its past: it is somewhat lenticular-like, with a central bulge and dust lanes reminiscent of the Sombrero Galaxy.
References
External links
12591
071392
Pegasus (constellation)
Spiral galaxies
+05-55-015 | UGC 12591 | [
"Astronomy"
] | 180 | [
"Pegasus (constellation)",
"Constellations"
] |
53,543,792 | https://en.wikipedia.org/wiki/Switching%20Kalman%20filter | The switching Kalman filtering (SKF) method is a variant of the Kalman filter. In its generalised form, it is often attributed to Kevin P. Murphy, but related switching state-space models have been in use.
Applications
Applications of the switching Kalman filter include: Brain–computer interfaces and neural decoding, real-time decoding for continuous neural-prosthetic control, and sensorimotor learning in humans.
It also has application in econometrics, signal processing, tracking, computer vision, etc. It is an alternative to the Kalman filter when the system's state has a discrete component. The additional error when using a Kalman filter instead of a Switching Kalman filter may be quantified in terms of the switching system's parameters. For example, when an industrial plant has "multiple discrete modes of behaviour, each of which having a linear (Gaussian) dynamics".
Model
There are several variants of SKF discussed in.
Special case
In the simpler case, switching state-space models are defined based on a switching variable which evolves independent of the hidden variable. The probabilistic model of such variant of SKF is as the following:
[This section is badly written: It does not explain the notation used below.]
The hidden variables include not only the continuous , but also a discrete *switch* (or switching) variable . The dynamics of the switch variable are defined by the term . The probability model of and can depend on .
The switch variable can take its values from a set . This changes the joint distribution which is a separate multivariate Gaussian distribution in case of each value of .
General case
In more generalised variants, the switch variable affects the dynamics of , e.g. through .
The filtering and smoothing procedure for general cases is discussed in.
References
Control theory
Nonlinear filters
Linear filters
Signal estimation
Stochastic differential equations
Robot control
Markov models | Switching Kalman filter | [
"Mathematics",
"Engineering"
] | 393 | [
"Robotics engineering",
"Applied mathematics",
"Control theory",
"Robot control",
"Dynamical systems"
] |
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