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https://en.wikipedia.org/wiki/Steady%20state%20%28biochemistry%29
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In biochemistry, steady state refers to the maintenance of constant internal concentrations of molecules and ions in the cells and organs of living systems. Living organisms remain at a dynamic steady state where their internal composition at both cellular and gross levels are relatively constant, but different from equilibrium concentrations. A continuous flux of mass and energy results in the constant synthesis and breakdown of molecules via chemical reactions of biochemical pathways. Essentially, steady state can be thought of as homeostasis at a cellular level.
Maintenance of steady state
Metabolic regulation achieves a balance between the rate of input of a substrate and the rate that it is degraded or converted, and thus maintains steady state. The rate of metabolic flow, or flux, is variable and subject to metabolic demands. However, in a metabolic pathway, steady state is maintained by balancing the rate of substrate provided by a previous step and the rate that the substrate is converted into product, keeping substrate concentration relatively constant.
Thermodynamically speaking, living organisms are open systems, meaning that they constantly exchange matter and energy with their surroundings. A constant supply of energy is required for maintaining steady state, as maintaining a constant concentration of a molecule preserves internal order and thus is entropically unfavorable. When a cell dies and no longer utilizes energy, its internal composition will proceed
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https://en.wikipedia.org/wiki/Counterion
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In chemistry, a counterion (sometimes written as "counter ion", pronounced as such) is the ion that accompanies an ionic species in order to maintain electric neutrality. In table salt (NaCl, also known as sodium chloride) the sodium ion (positively charged) is the counterion for the chloride ion (negatively charged) and vice versa.
A counterion will be more commonly referred to as an anion or a cation, depending on whether it is negatively or positively charged. Thus, the counterion to an anion will be a cation, and vice versa.
In biochemistry, counterions are generally vaguely defined. Depending on their charge, proteins are associated with a variety of smaller anions and cations. In plant cells, the anion malate is often accumulated in the vacuole to decrease water potential and drive cell expansion. To maintain neutrality, ions are often accumulated as the counterion. Ion permeation through hydrophobic cell walls is mediated by ion transport channels. Nucleic acids are anionic, the corresponding cations are often protonated polyamines.
Interfacial chemistry
Counterions are the mobile ions in ion exchange polymers and colloids. Ion-exchange resins are polymers with a net negative or positive charge. Cation-exchange resins consist of an anionic polymer with countercations, typically Na+ (sodium). The resin has a higher affinity for highly charged countercations, for example by Ca2+ (calcium) in the case of water softening. Correspondingly, anion-exchange resins are
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https://en.wikipedia.org/wiki/Surface%20bundle%20over%20the%20circle
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In mathematics, a surface bundle over the circle is a fiber bundle with base space a circle, and with fiber space a surface. Therefore the total space has dimension 2 + 1 = 3. In general, fiber bundles over the circle are a special case of mapping tori.
Here is the construction: take the Cartesian product of a surface with the unit interval. Glue the two copies of the surface, on the boundary, by some homeomorphism. This homeomorphism is called the monodromy of the surface bundle. It is possible to show that the homeomorphism type of the bundle obtained depends only on the conjugacy class, in the mapping class group, of the gluing homeomorphism chosen.
This construction is an important source of examples both in the field of low-dimensional topology as well as in geometric group theory. In the former we find that the geometry of the three-manifold is determined by the dynamics of the homeomorphism. This is the fibered part of William Thurston's geometrization theorem for Haken manifolds, whose proof requires the Nielsen–Thurston classification for surface homeomorphisms as well as deep results in the theory of Kleinian groups. In geometric group theory the fundamental groups of such bundles give an important class of HNN-extensions: that is, extensions of the fundamental group of the fiber (a surface) by the integers.
A simple special case of this construction (considered in Henri Poincaré's foundational paper) is that of a torus bundle.
See also
Virtually fibered
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https://en.wikipedia.org/wiki/Richard%20Ellis%20%28astronomer%29
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Richard Salisbury Ellis (born 25 May 1950, Colwyn Bay, Wales) is Professor of Astrophysics at the University College London. He previously served as the Steele Professor of Astronomy at the California Institute of Technology (Caltech).
He was awarded the 2011 Gold Medal of the Royal Astronomical Society, in 2022 the Royal Medal of the Royal Society and in 2023 the Gruber Prize in Cosmology.
Education
Ellis read astronomy at University College London and obtained a DPhil at Wolfson College at the University of Oxford in 1974.
Career and research
In 1985 he was appointed professor at the University of Durham (with two years at the Royal Greenwich Observatory) for his research contributions. In 1993 he moved to the University of Cambridge as the Plumian Professor and became a professorial fellow at Magdalene College. He served as director of the Institute of Astronomy from 1994 to 1999, at which point he moved to Caltech. Shortly after his arrival at Caltech, he was appointed as director of the Palomar Observatory which he later reorganized as the Caltech Optical Observatories taking into account the growing importance of Caltech's role in the Thirty Meter Telescope. After 16 years at Caltech, in September 2015 he returned to Europe via the award of a European Research Council Advanced Research Grant held at University College London (UCL).
Ellis works primarily in observational cosmology, considering the origin and evolution of galaxies, the evolution of large scale struc
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https://en.wikipedia.org/wiki/Wirth%E2%80%93Weber%20precedence%20relationship
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In computer science, a Wirth–Weber relationship between a pair of symbols is necessary to determine if a formal grammar is a simple precedence grammar. In such a case, the simple precedence parser can be used. The relationship is named after computer scientists Niklaus Wirth and Helmut Weber.
The goal is to identify when the viable prefixes have the pivot and must be reduced. A means that the pivot is found, a means that a potential pivot is starting, and a means that a relationship remains in the same pivot.
Formal definition
Precedence relations computing algorithm
We will define three sets for a symbol:
The pseudocode for computing relations is:
RelationTable := ∅
For each production
For each two adjacent symbols in
add(RelationTable, )
add(RelationTable, )
add(RelationTable, )
add(RelationTable, ) where is the initial non terminal of the grammar, and $ is a limit marker
add(RelationTable, ) where is the initial non terminal of the grammar, and $ is a limit marker
Examples
Head(a) = ∅
Head(S) = {a, c}
Head(b) = ∅
Head(c) = ∅
Tail(a) = ∅
Tail(S) = {b, c}
Tail(b) = ∅
Tail(c) = ∅
Head(a) = a
Head(S) = {a, c}
Head(b) = b
Head(c) = c
a Next to S
S Next to S
S Next to b
there is only one symbol, so no relation is added.
precedence table
Further reading
Formal languages
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https://en.wikipedia.org/wiki/F.%20Richard%20Stephenson
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F. Richard Stephenson (born Francis Richard Stephenson, 26 April 1941) is an Emeritus Professor at the University of Durham, in the Physics department and the East Asian Studies department. His research concentrates on historical aspects of astronomy, in particular analyzing ancient astronomical records to reconstruct the history of Earth's rotation. He has an asteroid named after him: 10979 Fristephenson.
Bibliography
& F. Richard Stephenson, The Historical supernovae, Pergamon Press, Oxford, 1977, 233 pages,
F. Richard Stephenson & David H. Clark, Applications of Early Astronomical Records, Oxford University Press, 1979, 124 pages,
Hermann Hunger, Christopher B. F. Walker, Richard Stephenson & Kevin K. C. Yau, Halley's Comet in History, British Museum Press, 1985, 64 pages,
F. Richard Stephenson, Supplement to the Tuckerman Tables, American Philosophical Society, 1986, 564 pages,
F. Richard Stephenson & M. A. Houlden, Atlas of historical eclipse maps. East Asia 1500 BC-AD 1900, Cambridge University Press, 1986,
F. Richard Stephenson, "The identification of early returns of comet Halley from ancient astronomical records", p. 203 - 214 in Comet Halley. Investigations, results, interpretations, Vol. 2, Prentice Hall, 1990
F. Richard Stephenson, Astronomical Observations from the Ancient Orient, Prentice Hall, 1990, 350 pages,
F. Richard Stephenson, Historical Eclipses and Earth's Rotation, Cambridge University Press, 1997, 573 pages,
F. Richard Stephens
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https://en.wikipedia.org/wiki/Simple%20precedence%20parser
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In computer science, a simple precedence parser is a type of bottom-up parser for context-free grammars that can be used only by simple precedence grammars.
The implementation of the parser is quite similar to the generic bottom-up parser. A stack is used to store a viable prefix of a sentential form from a rightmost derivation. The symbols ⋖, ≐ and ⋗ are used to identify the pivot, and to know when to Shift or when to Reduce.
Implementation
Compute the Wirth–Weber precedence relationship table for a grammar with initial symbol S.
Initialize a stack with the starting marker $.
Append an ending marker $ to the string being parsed (Input).
Until Stack equals "$ S" and Input equals "$"
Search the table for the relationship between Top(stack) and NextToken(Input)
if the relationship is ⋖ or ≐
Shift:
Push(Stack, relationship)
Push(Stack, NextToken(Input))
RemoveNextToken(Input)
if the relationship is ⋗
Reduce:
SearchProductionToReduce(Stack)
Remove the Pivot from the Stack
Search the table for the relationship between the nonterminal from the production and first symbol in the stack (Starting from top)
Push(Stack, relationship)
Push(Stack, Non terminal)
SearchProductionToReduce (Stack)
Find the topmost ⋖ in the stack; this and all the symbols above it are the Pivot.
Find the production of the grammar which has the Pivot as its right side.
Example
Given following language, which can parse arithmetic expressions with the multiplication and addition operations
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https://en.wikipedia.org/wiki/Exact%20differential%20equation
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In mathematics, an exact differential equation or total differential equation is a certain kind of ordinary differential equation which is widely used in Physics and engineering.
Definition
Given a simply connected and open subset D of and two functions I and J which are continuous on D, an implicit first-order ordinary differential equation of the form
is called an exact differential equation if there exists a continuously differentiable function F, called the potential function, so that
and
An exact equation may also be presented in the following form:
where the same constraints on I and J apply for the differential equation to be exact.
The nomenclature of "exact differential equation" refers to the exact differential of a function. For a function , the exact or total derivative with respect to is given by
Example
The function given by
is a potential function for the differential equation
First order exact differential equations
Identifying first order exact differential equations
Let the functions , , , and , where the subscripts denote the partial derivative with respect to the relative variable, be continuous in the region . Then the differential equation
is exact if and only if
That is, there exists a function , called a potential function, such that
So, in general:
Proof
The proof has two parts.
First, suppose there is a function such that
It then follows that
Since and are continuous, then and are also continuous which guarantees their eq
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https://en.wikipedia.org/wiki/Stuart%20A.%20Rice
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Stuart Alan Rice (born January 6, 1932) is an American theoretical chemist and physical chemist. He is well known as a theoretical chemist who also does experimental research, having spent much of his career working in multiple areas of physical chemistry. He is currently the Frank P. Hixon Distinguished Service Professor Emeritus at the University of Chicago. During his tenure at the University of Chicago, Rice has trained more than 100 Ph.D. students and postdoctoral researchers. He received the National Medal of Science in 1999.
Education and career
Stuart Rice attended the Bronx High School of Science, received his bachelor's degree in 1952 from Brooklyn College, and earned his master's and doctorate from Harvard University in 1954 and 1955, respectively. He was almost unable to attend graduate school due to contracting tuberculosis, but was cured of the disease through an experimental treatment of isoniazid and streptomycin. He remained at Harvard as a junior fellow for three years, although he spent the last two years of the fellowship doing research work at Yale University's chemistry department. After the fellowship, he joined the faculty of The University of Chicago in 1957, where he has remained since.
Rice has served the university in a wide variety of capacities during his fifty-seven year tenure. He served as the director of the James Franck Institute (the university's center for physical chemistry and condensed matter physics) from 1961 to 1967. He was
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https://en.wikipedia.org/wiki/Karma%20%28disambiguation%29
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Karma, in several Eastern religions, is the concept of "action" or "deed", understood as that which causes the entire cycle of cause and effect.
Karma may also refer to:
Computing
KARMA attack, an attack capable of exploiting some WiFi systems
Karma, a physics engine used in Unreal Engine 2
Karma, a trust metric in online moderation or rating systems
Karma, the voting system on Reddit
Karma spyware, an iPhone spyware tool used by Dark Matter
Film and television
Karma (1933 film), a Hindi- and English-language film
Karma (1981 film), a Filipino drama film
Karma (1986 film), an Indian Hindi film
Karma (1995 film), a Malayalam film of 1995
Karma (2008 Indian film), an English-language psychological thriller film
Karma (2008 Indonesian film), a paranormal drama film
Karma (2010 film), an Indian Telugu film
Karma (2012 film), a Sinhala adult drama film
Karma (2015 Thai film), a horror film
Karma (2015 Tamil film), a murder mystery film
Karma (2004 TV series), an Indian superhero television series
Karma (2015 TV series), a Hong Kong horror television series
Karma (2020 TV series), an American children's reality web series
"Karma" (How I Met Your Mother), a television episode
"Karma" (Person of Interest), a television episode
Music
Karma (American band), a progressive rock/jazz band
Karma Productions or Carvin & Ivan, a music production duo
Albums
Karma (Delerium album) (1997)
Karma (Robin Eubanks album) (1991)
Karma (Fanatic Crisis album) (1994)
Karma
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https://en.wikipedia.org/wiki/Sulfonyl%20group
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In organosulfur chemistry, a sulfonyl group can refer either to a functional group found primarily in sulfones, or to a substituent obtained from a sulfonic acid by the removal of the hydroxyl group, similarly to acyl groups. Sulfonyl groups can be written as having the general formula , where there are two double bonds between the sulfur and oxygen.
Sulfonyl groups can be reduced to the sulfide with DIBALH. Lithium aluminium hydride () reduces some but not all sulfones to sulfides.
In inorganic chemistry, when the group is not connected to any carbon atoms, it is referred to as sulfuryl.
Examples of sulfonyl group substituents
The names of sulfonyl groups typically end in -syl, such as:
{| class=wikitable
!Group name
!Full name
!Pseudoelement symbol
!Example
|-
|Tosyl
|p-toluenesulfonyl
|Ts
|Tosyl chloride (p-toluenesulfonyl chloride)CH3C6H4SO2Cl
|-
|Brosyl
|p-bromobenzenesulfonyl
|Bs
|
|-
|Nosyl
|o- or p-nitrobenzenesulfonyl
|Ns
|
|-
|Mesyl
|methanesulfonyl
|Ms
|Mesyl chloride (methanesulfonyl chloride)CH3SO2Cl
|-
|Triflyl
|trifluoromethanesulfonyl
|Tf
|
|-
|Tresyl
|2,2,2-trifluoroethyl-1-sulfonyl
|
|
|-
|Dansyl
|5-(dimethylamino)naphthalene-1-sulfonyl
|Ds
|Dansyl chloride
|}
See also
Sulfonyl halide
Sulfonamide
Sulfonate
Methylsulfonylmethane (MSM)
References
Functional groups
Organosulfur compounds
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https://en.wikipedia.org/wiki/Microbiology%20Society
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The Microbiology Society (previously the Society for General Microbiology) is a learned society based in the United Kingdom with a worldwide membership based in universities, industry, hospitals, research institutes and schools. It is the largest learned microbiological society in Europe. Interests of its members include basic and applied aspects of viruses, prions, bacteria, rickettsiae, mycoplasma, fungi, algae and protozoa, and all other aspects of microbiology. Its headquarters is at 14–16 Meredith Street, London. The Society's current president is Prof. Gurdyal S. Besra. The Society is a member of the Science Council.
History
The society was founded on 16 February 1945 as the Society for General Microbiology. Its first president was Alexander Fleming. The Society's first academic meeting was in July 1945 and its first journal, the Journal of General Microbiology (later renamed Microbiology), was published in 1947. A symposium series followed in 1949, and a sister journal, the Journal of General Virology, in 1967. The society purchased its own headquarters in Reading in 1971, after initially sharing accommodation with the Biochemical Society in London. In 2014 the Society moved to Charles Darwin House, London, sharing the premises with several other learned societies. In 2015, the Society changed its name to the Microbiology Society, after its members voted in favour of the change. In 2019 the Society moved to its new headquarters at 14–16 Meredith Street, London.
Activ
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https://en.wikipedia.org/wiki/Konstanty%20Hrynakowski
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Konstanty Hrynakowski (May 21, 1878 – September 4, 1938) was a Polish chemist.
He studied natural sciences at the St. Vladimir University, branching into inorganic chemistry and mineralogy at the Kiev Polytechnic Institute, and earning a degree in 1904.
Having participated in student riots during the 1905 revolution he was exiled to Siberia, where he worked at the Technological Institute in Tomsk as an assistant professor and physics and chemistry teacher.
He received a scholarship which enabled him to remove to Göttingen in Germany, where he was interned when the First World War broke out. Upon release from the internment camp he moved to Stockholm, where he worked at the High Technical School.
In March 1920 Hryniewiecki became the first director of the Pharmaceutical Chemistry Division at the University of Poznan. He revamped the basement of the Poznan castle to contain chemical and analytic laboratories and initiated the construction of Poznan's Collegium Chemicum.
Hryniewiecki published over 210 pieces, including over 100 scientific studies and several chemistry manuals. He presided over the Poznan branch of the Polish Chemistry Association and was vice-president of the national PCA office.
1878 births
1938 deaths
Polish chemists
Polish exiles in the Russian Empire
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https://en.wikipedia.org/wiki/Gmelinite
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Gmelinite-Na is one of the rarer zeolites but the most common member of the gmelinite series, gmelinite-Ca, gmelinite-K and gmelinite-Na. It is closely related to the very similar mineral chabazite. Gmelinite was named as a single species in 1825 after Christian Gottlob Gmelin (1792–1860) professor of chemistry and mineralogist from Tübingen, Germany, and in 1997 it was raised to the status of a series.Gmelinite-Na has been synthesised from Na-bearing aluminosilicate gels. The naturally occurring mineral forms striking crystals, shallow, six sided double pyramids, which can be colorless, white, pale yellow, greenish, orange, pink, and red. They have been compared to an angular flying saucer.
Structure
The aluminosilicate framework is composed of tetrahedra linked to form parallel double six-membered rings stacked in two different positions (A and B) in the repeating arrangement AABBAABB. The framework has no Al-Si order. Within the structure there are cavities with a cross-section of up to 4 Å, and also wide channels parallel to the c axis with a diameter of 6.4 Å. Space group: P63/mmc. Unit cell parameters: a=13.72 Å, c=9.95 Å, Z=4.
Environment
Generally occurs in Si-poor volcanic rocks, marine basalts and breccias, associated with other sodium zeolites such as analcime, , natrolite, , and chabazite-Na, . It also occurs in Na-rich pegmatites in alkaline rocks, and as an alteration product in some nepheline syenite intrusions. No sedimentary gmelinite has been fo
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https://en.wikipedia.org/wiki/Mike%20Bate
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Christopher Michael Bate, FRS (born 21 December 1943) is an Emeritus Professor of developmental biology at the Department of Zoology and fellow at King's College, Cambridge.
The son of John Gordon Bate, M.B. Ch.B., an R.A.F. doctor, of Holmbury St Mary, Dorking, his paternal grandfather was Herbert Bate, Dean of York 1932–41. His mother, Rachel Denise, was daughter of Samuel Ronald Courthope Bosanquet, KC, recorder of Walsall, Chancellor of the Diocese of Hertford; a great-uncle on the maternal side, William Temple, was Archbishop of Canterbury from 1942 to 1944.
Mike Bate is a member of European Molecular Biology Organization. His research is concerned with the way in which the machinery underlying coordinated movement is assembled during embryonic development. This involves both the analysis of the way in which muscles are assembled, specified and patterned, and the investigation of the way in which motor circuits are generated and begin to function.
Bate worked with the fruit fly, Drosophila melanogaster and applied a combination of genetic, molecular and cellular techniques to bear on the issues of neuromuscular development. Mike Bate also worked on the genetic basis of myoblast recruitment and fusion and on an electrophysiological and structural analysis of the way in which functional properties are acquired by embryonic neurons.
References
External links
Website at the Department of Zoology
"Michael Bate Interview", Alan Macfarlane, 2 July 2008
English biologist
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https://en.wikipedia.org/wiki/Alexandre%20Deulofeu
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Alexandre Deulofeu i Torres (20 September 1903, in L'Armentera – 27 December 1978, in Figueres) was a Catalan politician and philosopher of history. He wrote about what he called the Mathematics of History, a cyclical theory on the evolution of civilizations.
Biography
Deulofeu was born at l'Armentera in the province of Girona, Catalonia, where his father was a pharmacist. When he was three years old his family moved to Sant Pere Pescador, and then to Figueres nine years later.
He attended high school in the Institut Ramon Muntaner of Barcelona. Later he studied pharmacy and chemistry in Madrid, completing his studies in chemistry in Barcelona. Once back in Figueres, after a competitive examination he was awarded a teaching post at the Institute of Figueres. At the same time, he became strongly involved in politics. First he was a leader of the Republican Nationalist Youth in Empordà and afterwards he became a town councilor of the independentist party ERC (Esquerra Republicana de Catalunya). During the Spanish Civil War he became mayor of Figueres by chance, and while serving in this office he tried to keep the peace, and prevent looting and political witch hunts. He also served in the Republican Army as a health officer.
On 5 February 1939, Deulofeu accompanied the defeated republican forces into exile where he followed several trades: working as a teacher of various subjects; experimenting with farming, particularly hydroponics inventing his own growth solutions; worki
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https://en.wikipedia.org/wiki/Glutaric%20acid
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Glutaric acid is the organic compound with the formula C3H6(COOH)2. Although the related "linear" dicarboxylic acids adipic and succinic acids are water-soluble only to a few percent at room temperature, the water-solubility of glutaric acid is over 50% (w/w).
Biochemistry
Glutaric acid is naturally produced in the body during the metabolism of some amino acids, including lysine and tryptophan. Defects in this metabolic pathway can lead to a disorder called glutaric aciduria, where toxic byproducts build up and can cause severe encephalopathy.
Production
Glutaric acid can be prepared by the ring-opening of butyrolactone with potassium cyanide to give the mixed potassium carboxylate-nitrile that is hydrolyzed to the diacid. Alternatively hydrolysis, followed by oxidation of dihydropyran gives glutaric acid. It can also be prepared from reacting 1,3-dibromopropane with sodium or potassium cyanide to obtain the dinitrile, followed by hydrolysis.
Uses
1,5-Pentanediol, a common plasticizer and precursor to polyesters is manufactured by hydrogenation of glutaric acid and its derivatives.
Glutaric acid itself has been used in the production of polymers such as polyester polyols, polyamides. The odd number of carbon atoms (i.e. 5) is useful in decreasing polymer elasticity.
Pyrogallol can be produced from glutaric diester.
Safety
Glutaric acid may cause irritation to the skin and eyes. Acute hazards include the fact that this compound may be harmful by ingestion, inhalation or
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https://en.wikipedia.org/wiki/Qutb%20al-Din%20al-Shirazi
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Qotb al-Din Mahmoud b. Zia al-Din Mas'ud b. Mosleh Shirazi (1236–1311) () was a 13th-century Persian polymath and poet who made contributions to astronomy, mathematics, medicine, physics, music theory, philosophy and Sufism.
Biography
He was born in Kazerun in October 1236 to a family with a tradition of Sufism. His father, Zia' al-Din Mas'ud Kazeruni was a physician by profession and also a leading Sufi of the Kazeruni order. Zia' Al-Din received his Kherqa (Sufi robe) from Shahab al-Din Omar Suhrawardi. Qutb al-Din was garbed by the Kherqa (Sufi robe) as blessing by his father, aged ten. Later on, he also received his own robe from the hands of Najib al-Din Bozgush Shirazni, a famous Sufi of the time. Quṭb al-Din began studying medicine under his father. His father practiced and taught medicine at the Mozaffari hospital in Shiraz. After his father's death (when Qutb al-Din was 14), his uncle and other masters of the period trained him in medicine. He also studied the Qanun (the Canon) of the famous Persian scholar Avicenna and its commentaries. In particular he read the commentary of Fakhr al-Din Razi on the Canon of Medicine and Qutb al-Din raised many issues of his own. This led to his own decision to write his own commentary, where he resolved many of the issues in the company of Nasir al-Din al-Tusi.
Qutb al-Din replaced his father as the ophthalmologist at the Mozaffari hospital in Shiraz. At the same time, he pursued his education under his uncle Kamal al-D
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https://en.wikipedia.org/wiki/Two-hybrid%20screening
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Two-hybrid screening (originally known as yeast two-hybrid system or Y2H) is a molecular biology technique used to discover protein–protein interactions (PPIs) and protein–DNA interactions by testing for physical interactions (such as binding) between two proteins or a single protein and a DNA molecule, respectively.
The premise behind the test is the activation of downstream reporter gene(s) by the binding of a transcription factor onto an upstream activating sequence (UAS). For two-hybrid screening, the transcription factor is split into two separate fragments, called the DNA-binding domain (DBD or often also abbreviated as BD) and activating domain (AD). The BD is the domain responsible for binding to the UAS and the AD is the domain responsible for the activation of transcription. The Y2H is thus a protein-fragment complementation assay.
History
Pioneered by Stanley Fields and Ok-Kyu Song in 1989, the technique was originally designed to detect protein–protein interactions using the Gal4 transcriptional activator of the yeast Saccharomyces cerevisiae. The Gal4 protein activated transcription of a gene involved in galactose utilization, which formed the basis of selection. Since then, the same principle has been adapted to describe many alternative methods, including some that detect protein–DNA interactions or DNA-DNA interactions, as well as methods that use different host organisms such as Escherichia coli or mammalian cells instead of yeast.
Basic premise
The ke
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https://en.wikipedia.org/wiki/Henry%20Marshall%20Tory%20Medal
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The Henry Marshall Tory Medal is an award of the Royal Society of Canada "for outstanding research in a branch of astronomy, chemistry, mathematics, physics, or an allied science". It is named in honour of Henry Marshall Tory and is awarded bi-annually. The award consists of a gold plated silver medal.
Recipients
Source: Royal Society of Canada
See also
List of general science and technology awards
List of awards named after people
References
Canadian science and technology awards
Royal Society of Canada
Awards established in 1943
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https://en.wikipedia.org/wiki/Dysteleology
|
Dysteleology is the philosophical view that existence has no telos - no final cause from purposeful design.
Ernst Haeckel (1834-1919) invented and popularized the term dysteleology ().
See also
References
External links
Concepts in metaphysics
Teleology
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https://en.wikipedia.org/wiki/Donato%20Giancola
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Donato Giancola is an American artist specializing in narrative realism with science fiction and fantasy content.
Biography
Donato Giancola was born and raised in Colchester, near Burlington, in the state of Vermont. He currently resides in Brooklyn with his wife and two daughters.
Giancola first majored in electrical engineering at the University of Vermont, but left for Syracuse University to seriously pursue painting in 1989. He graduated with a BFA in 1992.
Giancola describes himself and his work as a "classical-abstract-realist working with science fiction and fantasy" and lists Hans Memling, Jan van Eyck, Velázquez, Caravaggio, Vermeer, Piet Mondrian, Rembrandt, Rubens and Titian as his favorite artists.
Giancola has illustrated cards for the Magic: The Gathering collectible card game. He has been described as a "cult hero" among fantasy collectible card game players. In 2008, the Bennington Banner referred to him as "arguably the most popular and successful sci-fi/fantasy artist working today".
In 2021 U.S. Postal Service announced that a "three ounce" stamp featuring Ursula K. Le Guin would be issued later that year, featuring a portrait of Le Guin based on a 2006 photograph, against a background scene from The Left Hand of Darkness, created by Giancola and art director Antonio Alcalá.
Honors
Giancola's work has won many awards and accolades with highlights including:
Hamilton King Award for Excellence, Society of Illustrators, 2008.
World Fantasy Award: Best
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https://en.wikipedia.org/wiki/Ruth%20Millikan
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Ruth Garrett Millikan (born 1933) is a leading American philosopher of biology, psychology, and language. Millikan has spent most of her career at the University of Connecticut, where she is now Professor Emerita of Philosophy.
Education and career
Millikan earned her BA from Oberlin College in 1955. At Yale University she studied under Wilfrid Sellars. Although W. Sellars left for the University of Pittsburgh midway through Millikan's doctorate, she stayed at Yale and earned her PhD in 1969. She and Paul Churchland are often considered leading proponents of "right wing" (i.e., who emphasize Sellars’s scientific realism) Sellarsianism.
Millikan taught half-time at Berea College from 1969–1972, Two-thirds time at Western Michigan University from 1972–1973, half-time at the University of Michigan from 1993–1996, but otherwise spent her entire career at the University of Connecticut, where she is now professor emerita. She is married to American psychologist and cognitive scientist Donald Shankweiler.
She was awarded the Jean Nicod Prize and gave the Jean Nicod Lectures in Paris in 2002. She was elected to the American Academy of Arts and Sciences in 2014. In 2017, she received both the Nicholas Rescher Prize for Systematic Philosophy from the University of Pittsburgh and the Rolf Schock Prize in Logic and Philosophy.
Philosophical work
Millikan is most famous for the view which, in her 1989 paper of the same name, she refers to as "biosemantics". Biosemantics is a theo
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https://en.wikipedia.org/wiki/James%20Curley%20%28astronomer%29
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James Curley (26 October 1796 – 24 July 1889) was an Irish-American astronomer.
He was born at Athleague, County Roscommon, Ireland. His early education was limited, though his talent for mathematics was discovered, and to some extent developed, by a teacher in his native town. He left Ireland in his youth, arriving in Philadelphia on 10 October 1817. Here he worked for two years as a bookkeeper and then taught mathematics at Frederick, Maryland.
In 1826 he became a student at the old seminary in Washington, DC, intending to prepare himself for the Catholic priesthood, and at the same time taught one of its classes. The seminary, however, which had been established in 1820, was closed in the following year and he joined the Society of Jesus on 29 September 1827. After completing his novitiate he again taught in Frederick and was sent in 1831 to teach natural philosophy at Georgetown University. He also studied theology and was ordained priest on 1 June 1833. His first Mass was said at the Georgetown Visitation Monastery, Georgetown, where he afterwards acted as chaplain for fifty years.
He spent the remainder of his life at Georgetown, where he taught natural philosophy and mathematics for forty-eight years. He planned and superintended the building of the Georgetown Observatory in 1844 and was its first director, filling this position for many years. One of his earliest achievements was the determination of the latitude and longitude of Washington, D.C. in 1846. His resul
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https://en.wikipedia.org/wiki/Nichols%20plot
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The Nichols plot is a plot used in signal processing and control design, named after American engineer Nathaniel B. Nichols.
Use in control design
Given a transfer function,
with the closed-loop transfer function defined as,
the Nichols plots displays versus . Loci of constant and are overlaid to allow the designer to obtain the closed loop transfer function directly from the open loop transfer function. Thus, the frequency is the parameter along the curve. This plot may be compared to the Bode plot in which the two inter-related graphs - versus and versus ) - are plotted.
In feedback control design, the plot is useful for assessing the stability and robustness of a linear system. This application of the Nichols plot is central to the quantitative feedback theory (QFT) of Horowitz and Sidi, which is a well known method for robust control system design.
In most cases, refers to the phase of the system's response. Although similar to a Nyquist plot, a Nichols plot is plotted in a Cartesian coordinate system while a Nyquist plot is plotted in a Polar coordinate system.
See also
Hall circles
Bode plot
Nyquist plot
Transfer function
References
External links
Mathematica function for creating the Nichols plot
Plots (graphics)
Signal processing
Classical control theory
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https://en.wikipedia.org/wiki/Poly1305
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Poly1305 is a universal hash family designed by Daniel J. Bernstein for use in cryptography.
As with any universal hash family, Poly1305 can be used as a one-time message authentication code to authenticate a single message using a secret key shared between sender and recipient,
similar to the way that a one-time pad can be used to conceal the content of a single message using a secret key shared between sender and recipient.
Originally Poly1305 was proposed as part of Poly1305-AES,
a Carter–Wegman authenticator
that combines the Poly1305 hash with AES-128 to authenticate many messages using a single short key and distinct message numbers.
Poly1305 was later applied with a single-use key generated for each message using XSalsa20 in the NaCl crypto_secretbox_xsalsa20poly1305 authenticated cipher,
and then using ChaCha in the ChaCha20-Poly1305 authenticated cipher
deployed in TLS on the internet.
Description
Definition of Poly1305
Poly1305 takes a 16-byte secret key and an -byte message and returns a 16-byte hash .
To do this, Poly1305:
Interprets as a little-endian 16-byte integer.
Breaks the message into consecutive 16-byte chunks.
Interprets the 16-byte chunks as 17-byte little-endian integers by appending a 1 byte to every 16-byte chunk, to be used as coefficients of a polynomial.
Evaluates the polynomial at the point modulo the prime .
Reduces the result modulo encoded in little-endian return a 16-byte hash.
The coefficients of the polynomial , where , ar
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https://en.wikipedia.org/wiki/DED
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Ded or DED may refer to:
Ded (band), an American nu metal band from Tempe, Arizona
Ded, Bishop of Vác, Hungarian 12th-century prelate
Data element definition, associated with a data element within a data dictionary
Dead End Derby, a roller derby league in Christchurch, New Zealand
Death effector domain, a signalling pathway in cell biology
DED Basketball Club, a Dutch basketball club
Dedicated hosting service, a type of Internet hosting
Dedua language, spoken in Papua New Guinea
DeLand Municipal Airport, in DeLand, Florida, United States
Department of Economic Development (disambiguation)
Deutscher Entwicklungsdienst, German Development Service
Directed Energy Deposition, ASTM International defined Additive Manufacturing Process
District electoral divisions, in Ireland, since 1996 termed electoral divisions
Diyar-e-Dil, a Pakistani television series
Doctor of Education (D.Ed.)
Dog Eat Dog (disambiguation)
Dog eat Doug, an American comic strip
Double-ended dildo
Dutch elm disease, a disease of elm trees
Jolly Grant Airport, serving Dehradun, Uttarakhand, India
Deferred Enforced Departure, an immigration status in the U.S. similar to Temporary Protected Status
Dragging equipment detector, a type of defect detector
Diabetic eye disease, also known as diabetic retinopathy
Disjunctive embedded dependency a type of constraint on a relational database
See also
Dead (disambiguation)
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https://en.wikipedia.org/wiki/Richard%20Inwood
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Richard Neil Inwood (4 March 1946 - 14 April 2019) was a Bishop suffragan of Bedford.
Inwood was born in Burton-on-Trent and studied chemistry at University College, Oxford and theology at the University of Nottingham. Before ordination, he spent a year teaching in north-west Uganda and worked as a research and development chemist with Imperial Chemical Industries (ICI) in Manchester for nearly two years. He served in Sheffield, London, Bath and Yeovil before his appointment in 1995 as Archdeacon of Halifax. He was consecrated a bishop by Rowan Williams, Archbishop of Canterbury at Southwark Cathedral on 7 March 2003.
From 9 April 2014 until 8 April 2015, he was Acting Bishop of Southwell and Nottingham at the request of the Archbishop of York. As acting bishop, Inwood attracted media attention in June 2014 for revoking the permission to officiate of a gay priest, Jeremy Pemberton, who had legally married his partner in spite of a pastoral statement issued by the church's bishops. In August 2014, Pemberton had an offer of work at Sherwood Forest Hospitals NHS Foundation Trust withdrawn following Inwood's refusal to grant the relevant licence.
Inwood was the co-author of Moved by Steam: Beside the tracks and on the trains 1962-67 with Mike Smith (Kettering, 2009 ). His wife, Liz, is a mathematics teacher and examiner.
Inwood died on 14 April 2019.
Styles
Richard Inwood Esq (1946–c1975)
The Revd Richard Inwood (c1975–1995)
The Ven Richard Inwood (1995–2003)
The Rt Revd Ri
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https://en.wikipedia.org/wiki/Spacetime%20symmetries
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Spacetime symmetries are features of spacetime that can be described as exhibiting some form of symmetry. The role of symmetry in physics is important in simplifying solutions to many problems. Spacetime symmetries are used in the study of exact solutions of Einstein's field equations of general relativity. Spacetime symmetries are distinguished from internal symmetries.
Physical motivation
Physical problems are often investigated and solved by noticing features which have some form of symmetry. For example, in the Schwarzschild solution, the role of spherical symmetry is important in deriving the Schwarzschild solution and deducing the physical consequences of this symmetry (such as the nonexistence of gravitational radiation in a spherically pulsating star). In cosmological problems, symmetry plays a role in the cosmological principle, which restricts the type of universes that are consistent with large-scale observations (e.g. the Friedmann–Lemaître–Robertson–Walker (FLRW) metric). Symmetries usually require some form of preserving property, the most important of which in general relativity include the following:
preserving geodesics of the spacetime
preserving the metric tensor
preserving the curvature tensor
These and other symmetries will be discussed below in more detail. This preservation property which symmetries usually possess (alluded to above) can be used to motivate a useful definition of these symmetries themselves.
Mathematical definition
A rigorous defini
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https://en.wikipedia.org/wiki/KIR
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KIR, Kir or kir may refer to:
Biology
Inward-rectifier potassium channel Kir
Killer-cell immunoglobulin-like receptor, a receptor protein expressed on the surface of natural killer cells and some T-cells
Bodies of water
Kir (river), in northern Albania
Kir Lake, near Dijon, France
People
Kir Fard, Armenian nobleman of the 12th–13th centuries
Kir Nesis (1934–2003), Russian biologist
Kir Bulychev, Russian writer
Félix Kir (1876–1968), priest in the French Resistance
Kir, a character in Detective Conan
Places
Republic of Kiribati in the central Pacific (ISO code: KIR)
Kir of Moab, biblical stronghold
Land of Kir, biblical location
Transport
Katihar Junction railway station, Bihar; station code KIR
Kerry Airport, Ireland (IATA code: KIR)
Kirkby railway station, Merseyside, England; National Rail station code KIR
Other
Kir (cocktail), alcoholic beverage
Kyrgyz language (ISO code: kir)
Krajowa Izba Rozliczeniowa, an automated clearing house in Poland
See also
Kirs (disambiguation)
Kyr
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https://en.wikipedia.org/wiki/Relativistic%20mechanics
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In physics, relativistic mechanics refers to mechanics compatible with special relativity (SR) and general relativity (GR). It provides a non-quantum mechanical description of a system of particles, or of a fluid, in cases where the velocities of moving objects are comparable to the speed of light c. As a result, classical mechanics is extended correctly to particles traveling at high velocities and energies, and provides a consistent inclusion of electromagnetism with the mechanics of particles. This was not possible in Galilean relativity, where it would be permitted for particles and light to travel at any speed, including faster than light. The foundations of relativistic mechanics are the postulates of special relativity and general relativity. The unification of SR with quantum mechanics is relativistic quantum mechanics, while attempts for that of GR is quantum gravity, an unsolved problem in physics.
As with classical mechanics, the subject can be divided into "kinematics"; the description of motion by specifying positions, velocities and accelerations, and "dynamics"; a full description by considering energies, momenta, and angular momenta and their conservation laws, and forces acting on particles or exerted by particles. There is however a subtlety; what appears to be "moving" and what is "at rest"—which is termed by "statics" in classical mechanics—depends on the relative motion of observers who measure in frames of reference.
Although some definitions and conce
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https://en.wikipedia.org/wiki/George%20Beck%20%28artist%29
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George Beck (1749 – December 24, 1812) was an artist and poet who flourished in America during the early republic era.
Biography
Beck was born in England in 1749. He was employed as an instructor in mathematics at Woolwich from 1776, but was afterward dismissed. He emigrated to the United States in 1795, and was employed in painting pictures. One of his paintings, The Great Falls of the Potomac (1796) was purchased by President George Washington. Washington hung the painting in his parlor at Mount Vernon, where it remains today.
Beck also wrote short poems, made poetic translations from Anacreon, Homer, Virgil, and Horace, and in 1812 published Observations on the Comet.
In 1795, he served as a scout in General Anthony Wayne's campaign against the Native Americans.
With his wife Mary Menessier Beck, who was also an artist, Beck conducted a female seminary in Lexington, Kentucky for many years. He died in Lexington on December 24, 1812.
Review
The obituary of Beck published in the Kentucky Gazette eulogized his nature paintings as one of the best among the works of the contemporary artists. However, he rarely was given any credit for his works and was driven in his later days to a life of drudgery at the school he was running, frustration and bitterness.
Although Beck failed to command the respect and recognition, his paintings of wild nature and western landscapes, "The Potomac River Breaking through the Blue Ridge" and "The Great Falls of the Potomac" purchased by Geo
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https://en.wikipedia.org/wiki/Robert%20Maitland%20Brereton
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Robert Maitland Brereton (2 January 1834 – 7 December 1911) was an English railway engineer in India. In the United States he helped secure the first Act of Congress for the irrigation of California.
Engineering training
In 1853 Brereton studied practical mechanics at King's College London, entering the field of civil engineering upon graduating. He joined Brunel's design team, of which Brereton's second cousin R.P. Brereton was also a member. He worked on the Royal Albert Bridge across the River Tamar at Saltash, and the construction of the Cornish railway.
Brereton was first employed in Brunel's office in Duke St, London from 1854 to 1855 where he witnessed the building of the SS Great Eastern. In 1856 he worked on the engineering of the new Paddington Station, including bridges, warehouses, iron girder work, rail laying, and hydraulic and other machineries.
Great Indian Peninsula Railway
Robert Maitland Brereton came to India in 1857 to work under Robert Graham as an assistant engineer. While there, he started work on the construction of the Bombay to Calcutta Railway, which was to form the backbone of the Indian Railways.
In January 1858 Brereton escaped death twice when his camp at the Sake River was attacked and looted by a band of 500 Bhils, during the unrest associated with the Indian mutiny.
As he gained promotions, Brereton was eventually appointed chief engineer for the Grand Indian Peninsular Railway and undertook to complete the strategic connection across
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https://en.wikipedia.org/wiki/Altruism%20%28biology%29
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In biology, altruism refers to behaviour by an individual that increases the fitness of another individual while decreasing the fitness of themselves. Altruism in this sense is different from the philosophical concept of altruism, in which an action would only be called "altruistic" if it was done with the conscious intention of helping another. In the behavioural sense, there is no such requirement. As such, it is not evaluated in moral terms—it is the consequences of an action for reproductive fitness that determine whether the action is considered altruistic, not the intentions, if any, with which the action is performed.
The term altruism was coined by the French philosopher Auguste Comte in French, as altruisme, for an antonym of egoism. He derived it from the Italian altrui, which in turn was derived from Latin alteri, meaning "other people" or "somebody else".
Altruistic behaviours appear most obviously in kin relationships, such as in parenting, but may also be evident among wider social groups, such as in social insects. They allow an individual to increase the success of its genes by helping relatives that share those genes. Obligate altruism is the permanent loss of direct fitness (with potential for indirect fitness gain). For example, honey bee workers may forage for the colony. Facultative altruism is temporary loss of direct fitness (with potential for indirect fitness gain followed by personal reproduction). For example, a Florida scrub jay may help at the n
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https://en.wikipedia.org/wiki/Oxidative%20coupling
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Oxidative coupling in chemistry is a coupling reaction of two molecular entities through an oxidative process. Usually oxidative couplings are catalysed by a transition metal complex like in classical cross-coupling reactions, although the underlying mechanism is different due to the oxidation process that requires an external (or internal) oxidant. Many such couplings utilize dioxygen as the stoichiometric oxidant but proceed by electron transfer.
C-C Couplings
Many oxidative couplings generate new C-C bonds. Early examples involve coupling of terminal alkynes:
2 RC≡CH + 2 Cu(I) → RC≡C-C≡CR + 2 Cu + 2 H+
Coupling of methane
Coupling reactions involving methane are highly sought, related to C1 chemistry because C2 derivatives are far more valuable than methane. The oxidative coupling of methane gives ethylene:
2 + → + 2
Aromatic coupling
In oxidative aromatic coupling the reactants are electron-rich aromatic compounds. Typical substrates are phenols and typical catalysts are copper and iron compounds and enzymes. The first reported synthetic application dates back to 1868 with Julius Löwe and the synthesis of ellagic acid by heating gallic acid with arsenic acid or silver oxide. Another reaction is the synthesis of 1,1'-Bi-2-naphthol from 2-naphthol by iron chloride, discovered in 1873 by Alexander Dianin (S)-BINOL can be prepared directly from an asymmetric oxidative coupling of 2-naphthol with copper(II) chloride.
Other oxidative couplings
The oxygen e
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https://en.wikipedia.org/wiki/Dmitry%20Kholodov
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Dmitry Yuryevich Kholodov (; 21 July 1967 – 17 October 1994) was a Russian journalist who investigated corruption in the military and was assassinated on 17 October 1994 in Moscow.
Early life and education
Kholodov was born in Zagorsk (now Sergiyev Posad) on 21 June 1967. He studied physics.
Career
Kholodov began his working life alongside his parents at the defence industry institute in Klimovsk in the Moscow Region. Faced by limited career prospects he turned to journalism, first working for the local radio. In 1992, he became a reporter with the national Moskovsky Komsomolets daily newspaper.
In 1993, Kholodov travelled to hotspots around the former Soviet Union, reporting for Moskovsky Komsomolets. In particular, he was in Abkhazia during the Georgian-Abkhaz conflict and, as he witnessed the ethnic cleansing of Georgians in Abkhazia, sent many detailed reports, including one entitled "Sukhumi apocalypse".
In October 1993, Kholodov interviewed Defence Minister Pavel Grachev. For the next twelve months, on the basis of leaks from army and Ministry of Defence sources, he wrote and published numerous articles about high-level corruption in the military, especially concerning the misuse of funds intended to ease the withdrawal and resettlement of half a million former Soviet troops and their families who had been based in East Germany. Kholodov was due to speak at Duma hearings into these allegations, which supposedly reached as high as the defence minister himself, when h
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https://en.wikipedia.org/wiki/Planar%20chirality
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Planar chirality, also known as 2D chirality, is the special case of chirality for two dimensions.
Most fundamentally, planar chirality is a mathematical term, finding use in chemistry, physics and related physical sciences, for example, in astronomy, optics and metamaterials. Recent occurrences in latter two fields are dominated by microwave and terahertz applications as well as micro- and nanostructured planar interfaces for infrared and visible light.
In chemistry
This term is used in chemistry contexts, e.g., for a chiral molecule lacking an asymmetric carbon atom, but possessing two non-coplanar rings that are each dissymmetric and which cannot easily rotate about the chemical bond connecting them: 2,2'-dimethylbiphenyl is perhaps the simplest example of this case. Planar chirality is also exhibited by molecules like (E)-cyclooctene, some di- or poly-substituted metallocenes, and certain monosubstituted paracyclophanes. Nature rarely provides planar chiral molecules, cavicularin being an exception.
Assigning the configuration of planar chiral molecules
To assign the configuration of a planar chiral molecule, begin by selecting the pilot atom, which is the highest priority of the atoms that is not in the plane, but is directly attached to an atom in the plane. Next, assign the priority of the three adjacent in-plane atoms, starting with the atom attached to the pilot atom as priority 1, and preferentially assigning in order of highest priority if there is a choice.
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https://en.wikipedia.org/wiki/Axial%20chirality
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In chemistry, axial chirality is a special case of chirality in which a molecule contains two pairs of chemical groups in a non-planar arrangement about an axis of chirality so that the molecule is not superposable on its mirror image. The axis of chirality (or chiral axis) is usually determined by a chemical bond that is constrained against free rotation either by steric hindrance of the groups, as in substituted biaryl compounds such as BINAP, or by torsional stiffness of the bonds, as in the C=C double bonds in allenes such as glutinic acid. Axial chirality is most commonly observed in substituted biaryl compounds wherein the rotation about the aryl–aryl bond is restricted so it results in chiral atropisomers, as in various ortho-substituted biphenyls, and in binaphthyls such as BINAP.
Axial chirality differs from central chirality (point chirality) in that axial chirality does not require a chiral center such as an asymmetric carbon atom, the most common form of chirality in organic compounds. Bonding to asymmetric carbon has the form Cabcd where a, b, c, and d must be distinct groups. Allenes have the form and the groups need not all be distinct as long as groups in each pair are distinct: abC=C=Cab is sufficient for the compound to be chiral, as in penta-2,3-dienedioic acid. Similarly, chiral atropisomers of the form may have some identical groups (), as in BINAP.
Nomenclature
The enantiomers of axially chiral compounds are usually given the stereochemical labels (
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https://en.wikipedia.org/wiki/Chalcogenide%20glass
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Chalcogenide glass (pronounced hard ch as in chemistry) is a glass containing one or more chalcogens (sulfur, selenium and tellurium, but excluding oxygen). Up until recently, chalcogenide glasses (ChGs) were believed to be predominantly covalently bonded materials and classified as covalent network solids. A most recent and extremely comprehensive university study of more than 265 different ChG elemental compositions, representing 40 different elemental families now shows that the vast majority of chalcogenide glasses are more accurately defined as being predominantly bonded by the weaker van der Waals forces of atomic physics and more accurately classified as van der Waals network solids. They are not exclusively bonded by these weaker vdW forces, and do exhibit varying percentages of covalency, based upon their specific chemical makeup. Polonium is also a chalcogen but is not used because of its strong radioactivity. Chalcogenide materials behave rather differently from oxides, in particular their lower band gaps contribute to very dissimilar optical and electrical properties.
The classical chalcogenide glasses (mainly sulfur-based ones such as As-S or Ge-S) are strong glass-formers and possess glasses within large concentration regions. Glass-forming abilities decrease with increasing molar weight of constituent elements; i.e., S > Se > Te.
Chalcogenide compounds such as AgInSbTe and GeSbTe are used in rewritable optical disks and phase-change memory devices. They ar
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https://en.wikipedia.org/wiki/Mathematical%20formulation%20of%20the%20Standard%20Model
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This article describes the mathematics of the Standard Model of particle physics, a gauge quantum field theory containing the internal symmetries of the unitary product group . The theory is commonly viewed as describing the fundamental set of particles – the leptons, quarks, gauge bosons and the Higgs boson.
The Standard Model is renormalizable and mathematically self-consistent, however despite having huge and continued successes in providing experimental predictions it does leave some unexplained phenomena. In particular, although the physics of special relativity is incorporated, general relativity is not, and the Standard Model will fail at energies or distances where the graviton is expected to emerge. Therefore, in a modern field theory context, it is seen as an effective field theory.
Quantum field theory
The standard model is a quantum field theory, meaning its fundamental objects are quantum fields which are defined at all points in spacetime. QFT treats particles as excited states (also called quanta) of their underlying quantum fields, which are more fundamental than the particles. These fields are
the fermion fields, , which account for "matter particles";
the electroweak boson fields , and ;
the gluon field, ; and
the Higgs field, .
That these are quantum rather than classical fields has the mathematical consequence that they are operator-valued. In particular, values of the fields generally do not commute. As operators, they act upon a quantum state (ket
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https://en.wikipedia.org/wiki/Erik%20Prosperin
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Erik Prosperin (25 July 1739 – 4 April 1803) was a Swedish astronomer.
Prosperin was a lecturer in mathematics and physics at Uppsala University in 1767, professor of observational astronomy (Observator) in 1773 – 1796, and professor of Astronomy in 1797 – 1798. He became a member of the Royal Swedish Academy of Sciences (KVA) in Stockholm in 1771, a member of the Royal Society of Sciences in Uppsala in 1774 (secretary from 1786 onwards), and a member of the American Philosophical Society in 1803.
Prosperin was a famous calculator of orbits: comets, planets, and their satellites. He calculated the orbits of the new (discovered in 1781) planet Uranus — for which he proposed the names Astraea, Cybele, and Neptune — and its satellites. He was also one of the first to calculate the orbit of the first asteroid, 1 Ceres, in 1801.
Prosperin calculated orbits for a total of 84 comets, especially Comet Messier (C/1769 P1), Comet Lexell (D/1770 L1), the Great Comet of 1771 (C/1771 A1, 1770 II), Comet Montaigne (C/1774 P1), Comet Bode (C/1779 A1), and Comet Encke (2P/1795 V1).
The asteroid 7292 Prosperin was named in his honor.
References
External links
Prosperin at Uppsala University
Nordisk familjebok: Proskenion – Prosperin
1739 births
1803 deaths
18th-century Swedish astronomers
Academic staff of Uppsala University
Members of the Royal Society of Sciences in Uppsala
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https://en.wikipedia.org/wiki/Zernike%20polynomials
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In mathematics, the Zernike polynomials are a sequence of polynomials that are orthogonal on the unit disk. Named after optical physicist Frits Zernike, laureate of the 1953 Nobel Prize in Physics and the inventor of phase-contrast microscopy, they play important roles in various optics branches such as beam optics and imaging.
Definitions
There are even and odd Zernike polynomials. The even Zernike polynomials are defined as
(even function over the azimuthal angle ), and the odd Zernike polynomials are defined as
(odd function over the azimuthal angle ) where m and n are nonnegative integers with n ≥ m ≥ 0 (m = 0 for spherical Zernike polynomials), is the azimuthal angle, ρ is the radial distance , and are the radial polynomials defined below. Zernike polynomials have the property of being limited to a range of −1 to +1, i.e. . The radial polynomials are defined as
for an even number of n − m, while it is 0 for an odd number of n − m. A special value is
Other representations
Rewriting the ratios of factorials in the radial part as products of binomials shows that the coefficients are integer numbers:
.
A notation as terminating Gaussian hypergeometric functions is useful to reveal recurrences, to demonstrate that they are special cases of Jacobi polynomials, to write down the differential equations, etc.:
for n − m even.
The factor in the radial polynomial may be expanded in a Bernstein basis of for even or times a function of for odd in the range . The ra
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https://en.wikipedia.org/wiki/Entropic%20force
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In physics, an entropic force acting in a system is an emergent phenomenon resulting from the entire system's statistical tendency to increase its entropy, rather than from a particular underlying force on the atomic scale.
Mathematical formulation
In the canonical ensemble, the entropic force associated to a macrostate partition is given by
where is the temperature, is the entropy associated to the macrostate , and is the present macrostate.
Examples
Pressure of an ideal gas
The internal energy of an ideal gas depends only on its temperature, and not on the volume of its containing box, so it is not an energy effect that tends to increase the volume of the box as gas pressure does. This implies that the pressure of an ideal gas has an entropic origin.
What is the origin of such an entropic force? The most general answer is that the effect of thermal fluctuations tends to bring a thermodynamic system toward a macroscopic state that corresponds to a maximum in the number of microscopic states (or micro-states) that are compatible with this macroscopic state. In other words, thermal fluctuations tend to bring a system toward its macroscopic state of maximum entropy.
Brownian motion
The entropic approach to Brownian movement was initially proposed by R. M. Neumann. Neumann derived the entropic force for a particle undergoing three-dimensional Brownian motion using the Boltzmann equation, denoting this force as a diffusional driving force or radial force. In
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https://en.wikipedia.org/wiki/Z-matrix
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Z-matrix may mean:
Z-matrix (chemistry), a table of the locations of atoms comprising a molecule
Z-matrix (mathematics), a matrix whose off-diagonal entries are less than or equal to zero
It may also refer to:
The matrix of Z-parameters, a matrix characterizing an electrical network
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https://en.wikipedia.org/wiki/Government%20College%20of%20Arts%2C%20Science%20and%20Commerce%2C%20Khandola
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The Government College of Arts, Science and Commerce, Khandola is located 500 metres (1,625 feet) from the main town of Marcel, Goa, India. This college offers courses in Bachelor of Science (Computer Science & Microbiology), Bachelor of Commerce, Bachelor of Arts and Master of Arts in Geography.
References
External links
Universities and colleges in Goa
Education in North Goa district
Educational institutions in India with year of establishment missing
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https://en.wikipedia.org/wiki/Incoherent%20scatter
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Incoherent scattering is a type of scattering phenomenon in physics. The term is most commonly used when referring to the scattering of an electromagnetic wave (usually light or radio frequency) by random fluctuations in a gas of particles (most often electrons).
The most well known practical application is known as incoherent scatter radar theory, a ground-based technique for studying the Earth's ionosphere first proposed by Professor William E. Gordon in 1958. A radar beam scattering off electrons in the ionospheric plasma creates an incoherent scatter return. When an electromagnetic wave is transmitted through the atmosphere, each of the electrons in the ionospheric plasma essentially acts as an antenna excited by the incoming wave, and the wave is re-radiated from the electron. Since the electrons are all moving at varying speeds as a result of ionospheric dynamics and random thermal motion, the reflection from each electron is also Doppler shifted. The receiver on the ground then receives a signal composed of the superposition of the re-radiated waves from all the electrons in the path of the incoming wave.
Since the positively-charged ions also present in the ionosphere are orders of magnitude more massive, they are not as readily excited by the incoming electromagnetic wave in the way that the electrons are, so they do not re-radiate the signal. However, the electrons tend to remain close to the positively-charged ions. As a result, the distribution function of t
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https://en.wikipedia.org/wiki/All%20Around%20the%20World%20%28Oasis%20song%29
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"All Around the World" is a song by the English rock band Oasis. It was written by the band's lead guitarist and principal songwriter Noel Gallagher. Released on 12 January 1998 as the third single from their third studio album, Be Here Now (1997), it is the longest song ever recorded by Oasis with the exception of the Heathen Chemistry track with a 30 minute silence "Better Man" .The song peaked at number one on the UK Singles Chart, becoming the longest song ever to reach number one, and earned a Gold certification. This was the last Oasis single to be released on the Creation Records label. The song also reached number one in Ireland and peaked at number 15 on the US Billboard Modern Rock Tracks chart.
Nearly ten minutes long, the song is embellished with string and horn pieces, and is followed by the two-minute-long instrumental "All Around the World (Reprise)". Upon its release, the reviews were generally positive. As with many Oasis songs (such as "Whatever", "Acquiesce", "Live Forever") it sends the message that "everything's gonna be okay". This was their last UK single to feature rhythm guitarist Paul "Bonehead" Arthurs and bassist Paul McGuigan before they left the band in 1999.
History
The song was one of the first to be written by Noel, and there are recorded sessions of the band rehearsing it at the Boardwalk club as early as 1992. However, despite Noel's fondness for the song, it did not appear on their first two albums—Definitely Maybe and (What's the Story)
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https://en.wikipedia.org/wiki/Hellmann%E2%80%93Feynman%20theorem
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In quantum mechanics, the Hellmann–Feynman theorem relates the derivative of the total energy with respect to a parameter to the expectation value of the derivative of the Hamiltonian with respect to that same parameter. According to the theorem, once the spatial distribution of the electrons has been determined by solving the Schrödinger equation, all the forces in the system can be calculated using classical electrostatics.
The theorem has been proven independently by many authors, including Paul Güttinger (1932), Wolfgang Pauli (1933), Hans Hellmann (1937) and Richard Feynman (1939).
The theorem states
where
is a Hermitian operator depending upon a continuous parameter ,
, is an eigenstate (eigenfunction) of the Hamiltonian, depending implicitly upon ,
is the energy (eigenvalue) of the state , i.e. .
Note that there is a breakdown of the Hellmann-Feynman theorem close to quantum critical points in the thermodynamic limit.
Proof
This proof of the Hellmann–Feynman theorem requires that the wave function be an eigenfunction of the Hamiltonian under consideration; however, it is also possible to prove more generally that the theorem holds for non-eigenfunction wave functions which are stationary (partial derivative is zero) for all relevant variables (such as orbital rotations). The Hartree–Fock wavefunction is an important example of an approximate eigenfunction that still satisfies the Hellmann–Feynman theorem. Notable example of where the Hellmann–Feynman is not ap
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https://en.wikipedia.org/wiki/Dorothy%20Porter
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Dorothy Featherstone Porter (26 March 1954 – 10 December 2008) was an Australian poet. She was a recipient of the Christopher Brennan Award for lifetime achievement in poetry.
Early life
Porter was born in Sydney. Her father was barrister Chester Porter and her mother, Jean, was a high school chemistry teacher. Porter attended the Queenwood School for Girls. She graduated from the University of Sydney in 1975 with a Bachelor of Arts majoring in English and History.
Works and awards
Porter's awards include The Age Book of the Year for poetry, the National Book Council Award for The Monkey's Mask and the FAW Christopher Brennan Award for poetry. Two of her verse novels were shortlisted for the Miles Franklin Award: What a Piece of Work in 2000 and Wild Surmise in 2003. In 2000, the film The Monkey's Mask was made from her verse novel of the same name. In 2005, her libretto The Eternity Man, co-written with composer Jonathan Mills, was performed at the Sydney Festival.
Porter's last book published during her life was El Dorado, her fifth verse novel, about a serial child killer. The book was nominated for several awards including the inaugural Prime Minister's Literary Award in 2007 and for Best Fiction in the Ned Kelly Awards.
Two other works have been published posthumously: her poetry collection The Bee Hut (2009), as well as has her final completed work, an essay on literary criticism and emotions, entitled On Passion.
Porter, who found many outlets for writing, includ
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https://en.wikipedia.org/wiki/Notes%20on%20the%20Synthesis%20of%20Form
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Notes on the Synthesis of Form is a book by Christopher Alexander about the process of design.
Design
Alexander defines design as "the process of inventing things which display new physical order, organization, form, in response to function...".
Even though his focus was formed in architectural design and civil engineering, the core ideas underlying his approach can be applied to many other fields.
Influence
By the time it was published, the book was considered "one of the most important contemporary books about the art of design, what it is, and how to go about it."
The book influenced a number of leading software writers, including Larry Constantine, Ed Yourdon, Alan Cooper, and Tom DeMarco.
Alexander's later work
For some reasons – perhaps related to the mathematical difficulties he faced or to the paradigm shift taking place in the design methods movement through the 1960s and 1970s, or argument by the German designer Horst Rittel that design deals with 'wicked problems' that have well defined boundaries or rationales, and cannot be solved with rigid methodology advocated in Notes – Alexander did not continue to develop the formal parts of his approach, which, by that time, showed promise. Instead, he chose, temporarily, to work on patterns (A Pattern Language) together with other well-known architects (Sarah Ishikawa and Murray Silverstein). These patterns are visible or material manifestations of the driving forces underlying the synthesis of form. For an example,
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https://en.wikipedia.org/wiki/Variational%20perturbation%20theory
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In mathematics, variational perturbation theory (VPT) is a mathematical method to convert divergent power series in a small expansion parameter, say
,
into a convergent series in powers
,
where is a critical exponent (the so-called index of "approach to scaling" introduced by Franz Wegner). This is possible with the help of variational parameters, which are determined by optimization order by order in . The partial sums are converted to convergent partial sums by a method developed in 1992.
Most perturbation expansions in quantum mechanics are divergent for any small coupling strength . They can be made convergent by VPT (for details see the first textbook cited below). The convergence is exponentially fast.
After its success in quantum mechanics, VPT has been developed further to become an important mathematical tool in quantum field theory with its anomalous dimensions. Applications focus on the theory of critical phenomena. It has led to the most accurate predictions of critical exponents.
More details can be read here.
References
External links
Kleinert H., Path Integrals in Quantum Mechanics, Statistics, Polymer Physics, and Financial Markets, 3. Auflage, World Scientific (Singapore, 2004) (readable online here) (see Chapter 5)
Kleinert H. and Verena Schulte-Frohlinde, Critical Properties of φ4-Theories, World Scientific (Singapur, 2001); Paperback (readable online here) (see Chapter 19)
Asymptotic analysis
Perturbation theory
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https://en.wikipedia.org/wiki/Electronic%20correlation
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Electronic correlation is the interaction between electrons in the electronic structure of a quantum system. The correlation energy is a measure of how much the movement of one electron is influenced by the presence of all other electrons.
Atomic and molecular systems
Within the Hartree–Fock method of quantum chemistry, the antisymmetric wave function is approximated by a single Slater determinant. Exact wave functions, however, cannot generally be expressed as single determinants. The single-determinant approximation does not take into account Coulomb correlation, leading to a total electronic energy different from the exact solution of the non-relativistic Schrödinger equation within the Born–Oppenheimer approximation. Therefore, the Hartree–Fock limit is always above this exact energy. The difference is called the correlation energy, a term coined by Löwdin. The concept of the correlation energy was studied earlier by Wigner.
A certain amount of electron correlation is already considered within the HF approximation, found in the electron exchange term describing the correlation between electrons with parallel spin. This basic correlation prevents two parallel-spin electrons from being found at the same point in space and is often called Fermi correlation. Coulomb correlation, on the other hand, describes the correlation between the spatial position of electrons due to their Coulomb repulsion, and is responsible for chemically important effects such as London dispersio
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https://en.wikipedia.org/wiki/Diplosome
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In cell biology, a diplosome refers to the pair of centrioles which are arranged perpendicularly to one another located near the nucleus. The diplosome plays a role in many processes such as in primary cilium development, spermiogenesis of teleosts, and mitosis. The rigid arrangement of centrioles in a diplosome is generally established after the procentriole is formed during mitosis.
Role of Diplosome in Primary Cilia Development
Primary cilia develop from the diplosome. Although the mechanism is not defined, during prometaphase of mitosis the diplosome ungergoes many changes to allow cilium resorption to occur.
Role of Diplosome in Spermiogenesis of teleosts
The type of spermiogenesis the teleost will undergo is dependent on the location of the diplosome on the nucleus, which ultimately acts as the cause of where the flagellum will be. In type I spermiogenesis, the diplosome is located at a lateral position on the nucleus leading to a perpendicular flagellum to the nucleus. In type II spermiogenesis, the diplosome is located at the apical pole of the nucleus, creating a parallel flagellum to the nucleus. In both scenarios the diplosome will reach the nuclear fossa after nuclear roation.
Diplosome in Mitosis
Diplosomes first appear during G2 phase of the cell cycle. In the early stages of mitosis the diplosome will split and begin to move in opposite directions until both reach edges of the nucleus. At this point one diplosome will return to the center of the nucleus w
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https://en.wikipedia.org/wiki/Courant%E2%80%93Friedrichs%E2%80%93Lewy%20condition
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In mathematics, the convergence condition by Courant–Friedrichs–Lewy is a necessary condition for convergence while solving certain partial differential equations (usually hyperbolic PDEs) numerically. It arises in the numerical analysis of explicit time integration schemes, when these are used for the numerical solution. As a consequence, the time step must be less than a certain time in many explicit time-marching computer simulations, otherwise the simulation produces incorrect results. The condition is named after Richard Courant, Kurt Friedrichs, and Hans Lewy who described it in their 1928 paper.
Heuristic description
The principle behind the condition is that, for example, if a wave is moving across a discrete spatial grid and we want to compute its amplitude at discrete time steps of equal duration, then this duration must be less than the time for the wave to travel to adjacent grid points. As a corollary, when the grid point separation is reduced, the upper limit for the time step also decreases. In essence, the numerical domain of dependence of any point in space and time (as determined by initial conditions and the parameters of the approximation scheme) must include the analytical domain of dependence (wherein the initial conditions have an effect on the exact value of the solution at that point) to assure that the scheme can access the information required to form the solution.
Statement
To make a reasonably formally precise statement of the condition, it is n
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https://en.wikipedia.org/wiki/Georg%20Meiring
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General Georg Meiring (born 18 October 1939) is a South African military commander. He served as Chief of the Army (1990–93) and Chief of the South African National Defence Force (199398).
Military career
After obtaining a Master of Science in Physics from the University of the Orange Free State, Meiring joined the South African Army as a signals officer in 1962 and, in 1980, became Director of Signals of the South African Army.
Meiring served as Deputy Chief of the Army from 1982 to 1983 and as General Officer Commanding (GOC) South West Africa Territorial Force from 1983 to 1987. He was later GOC Far North Command, Deputy Chief of the Army again, Chief of the Army from 1990 to 1993, the last Chief of the South African Defence Force from 1993 to 1994, and the first Chief of the South African National Defence Force from 1994 to 1998.
Controversy
In February 1998, Meiring, in his capacity as the head of defence of South Africa had provided an intelligence report to President Nelson Mandela on an organisation by the name of "Front African People's Liberation Army". This report implicated many important government dignitaries on conspiracy to assassinate the president, murder judges, occupy parliament and broadcasting stations and cause mayhem in general. Later, after it was investigated by a judge, the report was claimed to be fabricated.
Awards and decorations
In 1998, Meiring was awarded the Star of South Africa, Gold. He also received the Order of the Cloud and Banner
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https://en.wikipedia.org/wiki/Schanuel%27s%20conjecture
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In mathematics, specifically transcendental number theory, Schanuel's conjecture is a conjecture made by Stephen Schanuel in the 1960s concerning the transcendence degree of certain field extensions of the rational numbers.
Statement
The conjecture is as follows:
Given any complex numbers that are linearly independent over the rational numbers , the field extension (z1, ..., zn, ez1, ..., ezn) has transcendence degree at least over .
The conjecture can be found in Lang (1966).
Consequences
The conjecture, if proven, would generalize most known results in transcendental number theory. The special case where the numbers z1,...,zn are all algebraic is the Lindemann–Weierstrass theorem. If, on the other hand, the numbers are chosen so as to make exp(z1),...,exp(zn) all algebraic then one would prove that linearly independent logarithms of algebraic numbers are algebraically independent, a strengthening of Baker's theorem.
The Gelfond–Schneider theorem follows from this strengthened version of Baker's theorem, as does the currently unproven four exponentials conjecture.
Schanuel's conjecture, if proved, would also settle whether numbers such as e + and ee are algebraic or transcendental, and prove that e and are algebraically independent simply by setting z1 = 1 and z2 = i, and using Euler's identity.
Euler's identity states that ei + 1 = 0. If Schanuel's conjecture is true then this is, in some precise sense involving exponential rings, the only relation between
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https://en.wikipedia.org/wiki/Bastardisation
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Bastardisation or bastardization may refer to:
Corruption (linguistics), the idea that language change constitutes a degradation in the quality
Hazing, activities involving harassment, abuse or humiliation used as a way of initiating a person into a group
Hybridisation (biology), mixing two animals or plants of different breeds, varieties, species or genera
Lacing (drugs)
Cultural appropriation, adoption of elements of a culture by members of another culture
See also
Bastard (disambiguation)
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https://en.wikipedia.org/wiki/Axiality
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Axiality may refer to:
Axiality (geometry), a measure of the axial symmetry of a two-dimensional shape
Axiality and rhombicity in mathematics, measures of the directional symmetry of a three-dimensional tensor
Axiality, a principle behind the art and poetry of George Quasha
Axiality in architecture, organization around a strong central axis, especially in the architecture of cathedrals and great churches and Beaux-Arts architecture
See also
Axial (disambiguation)
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https://en.wikipedia.org/wiki/Painlev%C3%A9%20transcendents
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In mathematics, Painlevé transcendents are solutions to certain nonlinear second-order ordinary differential equations in the complex plane with the Painlevé property (the only movable singularities are poles), but which are not generally solvable in terms of elementary functions. They were discovered by
,
,
, and
.
History
Painlevé transcendents have their origin in the study of special functions, which often arise as solutions of differential equations, as well as in the study of isomonodromic deformations of linear differential equations. One of the most useful classes of special functions are the elliptic functions. They are defined by second order ordinary differential equations whose singularities have the Painlevé property: the only movable singularities are poles. This property is rare in nonlinear equations. Poincaré and L. Fuchs showed that any first order equation with the Painlevé property can be transformed into the Weierstrass elliptic equation or the Riccati equation, which can all be solved explicitly in terms of integration and previously known special functions. Émile Picard pointed out that for orders greater than 1, movable essential singularities can occur, and found a special case of what was later called Painleve VI equation (see below).
(For orders greater than 2 the solutions can have moving natural boundaries.) Around 1900, Paul Painlevé studied second order differential equations with no movable singularities. He found that up to certain tr
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https://en.wikipedia.org/wiki/Timothy%20Ferris
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Timothy Ferris (born August 29, 1944) is an American science writer and the best-selling author of twelve books, including The Science of Liberty (2010) and Coming of Age in the Milky Way (1988), for which he was awarded the American Institute of Physics Prize and was nominated for the Pulitzer Prize. He also wrote The Whole Shebang: A State-of-the-Universe(s) Report (1997), a popular science book on the study of the universe. Ferris has produced three PBS documentaries: The Creation of the Universe, Life Beyond Earth, and Seeing in the Dark.
Background and education
Ferris is a native of Miami, Florida and a graduate of Coral Gables Senior High School. He attended Northwestern University, graduating in 1966 with majors in English and communications. He studied for one year at the Northwestern University Law School before joining United Press International as a reporter, working in New York City.
Writing and NASA
After starting his career as a newspaper reporter, Ferris became an editor at Rolling Stone, where he initially specialized in science journalism. Ferris produced the Voyager Golden Record, an artifact of human civilization containing music, sounds of Earth and encoded photographs launched aboard the Voyager 1 spacecraft. He has served as a consultant to NASA on long-term space exploration policy, and was among the journalists selected as candidates to fly aboard the Space Shuttle in 1986; the planned flight was cancelled due to the Challenger disaster. He was als
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https://en.wikipedia.org/wiki/Frank%20Cameron%20Jackson
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Frank Cameron Jackson (born 31 August 1943) is an Australian analytic philosopher and Emeritus Professor in the School of Philosophy (Research School of Social Sciences) at Australian National University (ANU) where he had spent most of the latter part of his career. His primary research interests include epistemology, metaphysics, meta-ethics and the philosophy of mind. In the latter field he is best known for the "Mary's room" knowledge argument, a thought experiment that is one of the most discussed challenges to physicalism.
Biography
Frank Cameron Jackson was born on 31 August 1943 in Melbourne, Australia. His parents were both philosophers. His mother Ann E. Jackson, who rose to the rank of senior tutor, taught philosophy at the University of Melbourne from 1961 to 1984. His atheistic father Allan Cameron Jackson (1911–1990) had been a student of Ludwig Wittgenstein (having gone to Cambridge in 1946 for Ph.D. studies). F. C. Jackson, in interview with Graham Oppy, reports of his parents that; they were both "philosophers in the Old School, by which I mean the Wittgensteinian School. Philosophy was part of your life."
Despite his self-reported enjoyment of the philosophical conversation of his household it was with view to becoming a mathematician that Jackson went to the University of Melbourne to study maths and science. And it was only in his final year of those studies that he chose to also take some philosophy which he found he better enjoyed and proved signif
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https://en.wikipedia.org/wiki/Robert%20Merrihew%20Adams
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Robert Merrihew Adams (born September 8, 1937) is an American analytic philosopher, specializing in metaphysics, philosophy of religion, ethics, and the history of early modern philosophy.
Life and career
Adams was born on September 8, 1937, in Philadelphia, Pennsylvania. He taught for many years at the University of California, Los Angeles, before moving to Yale University in the early 1990s as the Clark Professor of Moral Philosophy and Metaphysics. As chairman, he helped revive the philosophy department after its near-collapse due to personal and scholarly conflicts between analytical and Continental philosophers. Adams retired from Yale in 2004 and taught part-time at the University of Oxford in England, where he was a senior research fellow of Mansfield College. In 2009 he became a Distinguished Research Professor of Philosophy at the University of North Carolina at Chapel Hill.
Adams's late wife, Marilyn McCord Adams, was also a philosopher, working on medieval philosophy and the philosophy of religion and was the Regius Professor of Divinity at Christ Church, Oxford. In 2013 both became visiting research professors at Rutgers University, in conjunction with the founding of the Rutgers Center for the Philosophy of Religion.
He is a past president of the Society of Christian Philosophers. In 1999, he delivered the Gifford Lectures on "God and Being". He was elected a Fellow of the British Academy in 2006 and was elected a Fellow of the American Academy of Arts and S
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https://en.wikipedia.org/wiki/Covering%20set
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In mathematics, a covering set for a sequence of integers refers to a set of prime numbers such that every term in the sequence is divisible by at least one member of the set. The term "covering set" is used only in conjunction with sequences possessing exponential growth.
Sierpinski and Riesel numbers
The use of the term "covering set" is related to Sierpinski and Riesel numbers. These are odd natural numbers for which the formula (Sierpinski number) or (Riesel number) produces no prime numbers. Since 1960 it has been known that there exists an infinite number of both Sierpinski and Riesel numbers (as solutions to families of congruences based upon the set } but, because there are an infinitude of numbers of the form or for any , one can only prove to be a Sierpinski or Riesel number through showing that every term in the sequence or is divisible by one of the prime numbers of a covering set.
These covering sets form from prime numbers that in base 2 have short periods. To achieve a complete covering set, Wacław Sierpiński showed that a sequence can repeat no more frequently than every 24 numbers. A repeat every 24 numbers give the covering set }, while a repeat every 36 terms can give several covering sets: }; }; } and }.
Riesel numbers have the same covering sets as Sierpinski numbers.
Other covering sets
Covering sets (thus Sierpinski numbers and Riesel numbers) also exists for bases other than 2.
Covering sets are also used to prove the existence of composi
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https://en.wikipedia.org/wiki/154%20%28number%29
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154 (one hundred [and] fifty-four) is the natural number following 153 and preceding 155.
In mathematics
154 is a nonagonal number. Its factorization makes 154 a sphenic number
There is no integer with exactly 154 coprimes below it, making 154 a noncototient, nor is there, in base 10, any integer that added up to its own digits yields 154, making 154 a self number
154 is the sum of the first six factorials, if one starts with and assumes that .
With just 17 cuts, a pancake can be cut up into 154 pieces (Lazy caterer's sequence).
The distinct prime factors of 154 add up to 20, and so do the ones of 153, hence the two form a Ruth-Aaron pair. 154! + 1 is a factorial prime.
In music
154 is an album by Wire, named for the number of live gigs Wire had performed at that time
In the military
was a United States Navy Trefoil-class concrete barge during World War II
was a United States Navy Admirable-class minesweeper during World War II
was a United States Navy Wickes-class destroyer during World War II
was a United States Navy General G. O. Squier-class transport during World War II
was a United States Navy Haskell-class attack transport during World War II
was a United States Navy Buckley-class destroyer escort ship during World War II
Strike Fighter Squadron 154 (VFA-154) is a United States Navy strike fighter squadron stationed at Naval Air Station Lemoore
Convoy ON-154 was a convoy of ships in December 1942 during World War II
In sports
Major League Base
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https://en.wikipedia.org/wiki/Animal%20science
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Animal science is described as "studying the biology of animals that are under the control of humankind". It can also be described as the production and management of farm animals. Historically, the degree was called animal husbandry and the animals studied were livestock species, like cattle, sheep, pigs, poultry, and horses. Today, courses available look at a broader area, including companion animals, like dogs and cats, and many exotic species. Degrees in Animal Science are offered at a number of colleges and universities. Animal science degrees are often offered at land-grant universities, which will often have on-campus farms to give students hands-on experience with livestock animals.
Education
Professional education in animal science prepares students for careers in areas such as animal breeding, food and fiber production, nutrition, animal agribusiness, animal behavior, and welfare. Courses in a typical Animal Science program may include genetics, microbiology, animal behavior, nutrition, physiology, and reproduction. Courses in support areas, such as genetics, soils, agricultural economics and marketing, legal aspects, and the environment also are offered.
Bachelor degree
At many universities, a Bachelor of Science (BS) degree in Animal Science allows emphasis in certain areas. Typical areas are species-specific or career-specific. Species-specific areas of emphasis prepare students for a career in dairy management, beef management, swine management, sheep or sma
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https://en.wikipedia.org/wiki/EOSFET
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An EOSFET or electrolyte–oxide–semiconductor field-effect transistor is a FET, like a MOSFET, but with an electrolyte solution replacing the metal for the detection of neuronal activity. Many EOSFETs are integrated in a neurochip.
Electrochemistry
Sensors
Transistor types
MOSFETs
Field-effect transistors
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https://en.wikipedia.org/wiki/Radiochemistry
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Radiochemistry is the chemistry of radioactive materials, where radioactive isotopes of elements are used to study the properties and chemical reactions of non-radioactive isotopes (often within radiochemistry the absence of radioactivity leads to a substance being described as being inactive as the isotopes are stable). Much of radiochemistry deals with the use of radioactivity to study ordinary chemical reactions. This is very different from radiation chemistry where the radiation levels are kept too low to influence the chemistry.
Radiochemistry includes the study of both natural and man-made radioisotopes.
Main decay modes
All radioisotopes are unstable isotopes of elements— that undergo nuclear decay and emit some form of radiation. The radiation emitted can be of several types including alpha, beta, gamma radiation, proton, and neutron emission along with neutrino and antiparticle emission decay pathways.
1. α (alpha) radiation—the emission of an alpha particle (which contains 2 protons and 2 neutrons) from an atomic nucleus. When this occurs, the atom's atomic mass will decrease by 4 units and the atomic number will decrease by 2.
2. β (beta) radiation—the transmutation of a neutron into an electron and a proton. After this happens, the electron is emitted from the nucleus into the electron cloud.
3. γ (gamma) radiation—the emission of electromagnetic energy (such as gamma rays) from the nucleus of an atom. This usually occurs during alpha or beta radioactive deca
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https://en.wikipedia.org/wiki/Abstract%20analytic%20number%20theory
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Abstract analytic number theory is a branch of mathematics which takes the ideas and techniques of classical analytic number theory and applies them to a variety of different mathematical fields. The classical prime number theorem serves as a prototypical example, and the emphasis is on abstract asymptotic distribution results. The theory was invented and developed by mathematicians such as John Knopfmacher and Arne Beurling in the twentieth century.
Arithmetic semigroups
The fundamental notion involved is that of an arithmetic semigroup, which is a commutative monoid G satisfying the following properties:
There exists a countable subset (finite or countably infinite) P of G, such that every element a ≠ 1 in G has a unique factorisation of the form
where the pi are distinct elements of P, the αi are positive integers, r may depend on a, and two factorisations are considered the same if they differ only by the order of the factors indicated. The elements of P are called the primes of G.
There exists a real-valued norm mapping on G such that
The total number of elements of norm is finite, for each real .
Additive number systems
An additive number system is an arithmetic semigroup in which the underlying monoid G is free abelian. The norm function may be written additively.
If the norm is integer-valued, we associate counting functions a(n) and p(n) with G where p counts the number of elements of P of norm n, and a counts the number of elements of G of norm n. We
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https://en.wikipedia.org/wiki/EHP
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EHP may refer to:
E.H.P., a 1920s French automobile manufacturer
Eastern Highlands Province in Papua New Guinea
EHP spectral sequence in mathematics
(), Labourist Movement Party, a political party in Turkey
Environmental Health Perspectives, a scholarly journal
Environmental Planning & Historic Preservation (EHP), a Federal Emergency Management Agency (FEMA) program
Everglades Holiday Park, in Fort Lauderdale, Florida
Sahrawi peseta, the de facto currency of the Sahrawi Arab Democratic Republic
Electron-Hole Pairs, the fundamental unit of generation and recombination in semiconductors
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https://en.wikipedia.org/wiki/Janet%20Browne
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Elizabeth Janet Browne (née Bell, born 30 March 1950) is a British historian of science, known especially for her work on the history of 19th-century biology. She taught at the Wellcome Trust Centre for the History of Medicine, University College, London, before returning to Harvard. She is currently Aramont Professor of the History of Science at Harvard University.
Biography
Browne is the daughter of Douglas Bell CBE (1905–1993) and his wife Betty Bell. She married Nicholas Browne in 1972; they have two daughters.
Browne gained a BA degree from Trinity College, Dublin in 1972 and from Imperial College, London an MSc (1973) and PhD (1978) on the history of science. She was a research fellow at Harvard University. She received an honorary Doctor in Science (Sc. D) degree from Trinity College, Dublin in 2009 in recognition of her contribution to the biographical knowledge of Charles Darwin.
After working as an associate editor on the University of Cambridge Library project to collect, edit, and publish the correspondence of Charles Darwin, she wrote a two-volume biography of the naturalist: Charles Darwin: Voyaging (1995), on his youth and years on the Beagle, and Charles Darwin: The Power of Place (2002), covering the years after the publication of his theory of evolution. The latter book has received acclaim for its innovative interpretation of the role of Darwin's correspondence in the formation of his scientific theory and recruitment of scientific support. In 2004, thi
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https://en.wikipedia.org/wiki/Boris%20Mik%C5%A1i%C4%87
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Boris Mikšić (born 11 October 1948 in Zagreb) is a Croatian businessman and politician.
Mikšić was born in Zagreb, then part of SFR Yugoslavia. He graduated from the University of Zagreb Faculty of Mechanical Engineering and Naval Architecture in 1973. He then emigrated to the United States of America, settling in Minnesota where he gradually began his business, Cortec Corporation.
Over the years he became one of the wealthiest Croatian Americans. He first ventured into the Croatian politics as an independent candidate in the 2003 parliamentary elections.
In 2005, he ran as an independent candidate in the Croatian presidential election. His campaign was partially based on his autobiography Američki san dečka s Trešnjevke (American dream of a kid from Trešnjevka) that he had published in 1994 - creating image of a simple Zagreb youth, who fulfilled the American Dream. It was also based on his opposition to the ICTY and Eurosceptic views. His success story along with his self-funded American-style campaign brought a new perspective to many voters.
On 2 January, to the surprise of many, first election projections showed him as winning 2nd place, knocking the government's candidate Jadranka Kosor out of the race. Immediately, many commentators began to interpret his success as a protest vote against the Croatian political establishment, engulfed in corruption and being notoriously inefficient. As if Mikšić, already wealthy has been seen by voters as more decent and less corrup
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https://en.wikipedia.org/wiki/Trigamma%20function
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In mathematics, the trigamma function, denoted or , is the second of the polygamma functions, and is defined by
.
It follows from this definition that
where is the digamma function. It may also be defined as the sum of the series
making it a special case of the Hurwitz zeta function
Note that the last two formulas are valid when is not a natural number.
Calculation
A double integral representation, as an alternative to the ones given above, may be derived from the series representation:
using the formula for the sum of a geometric series. Integration over yields:
An asymptotic expansion as a Laurent series is
if we have chosen , i.e. the Bernoulli numbers of the second kind.
Recurrence and reflection formulae
The trigamma function satisfies the recurrence relation
and the reflection formula
which immediately gives the value for z : .
Special values
At positive half integer values we have that
Moreover, the trigamma function has the following special values:
where represents Catalan's constant.
There are no roots on the real axis of , but there exist infinitely many pairs of roots for . Each such pair of roots approaches quickly and their imaginary part increases slowly logarithmic with . For example, and are the first two roots with .
Relation to the Clausen function
The digamma function at rational arguments can be expressed in terms of trigonometric functions and logarithm by the digamma theorem. A similar result ho
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https://en.wikipedia.org/wiki/Caveolin
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In molecular biology, caveolins are a family of integral membrane proteins that are the principal components of caveolae membranes and involved in receptor-independent endocytosis. Caveolins may act as scaffolding proteins within caveolar membranes by compartmentalizing and concentrating signaling molecules. They also induce positive (inward) membrane curvature by way of oligomerization, and hairpin insertion. Various classes of signaling molecules, including G-protein subunits, receptor and non-receptor tyrosine kinases, endothelial nitric oxide synthase (eNOS), and small GTPases, bind Cav-1 through its 'caveolin-scaffolding domain'.
The caveolin gene family has three members in vertebrates: CAV1, CAV2, and CAV3, coding for the proteins caveolin-1, caveolin-2, and caveolin-3, respectively. All three members are membrane proteins with similar structure. Caveolin forms oligomers and associates with cholesterol and sphingolipids in certain areas of the cell membrane, leading to the formation of caveolae.
Structure and expression
The caveolins are similar in structure. They all form hairpin loops that are inserted into the cell membrane. Both the C-terminus and the N-terminus face the cytoplasmic side of the membrane. There are two isoforms of caveolin-1: caveolin-1α and caveolin-1β, the latter lacking a part of the N-terminus.
Caveolins are found in the majority of adherent, mammalian cells.
Caveolin-1 is most prominently expressed in endothelial, fibrous, and adipose ti
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https://en.wikipedia.org/wiki/Poondi%20Kumaraswamy
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Ponnambalam Kumaraswamy (often referred to as Poondi Kumaraswamy) (October 4, 1930 - March 9, 1988)
was an Indian hydrologist. He was elected a Fellow of the Indian Academy of Sciences in 1972 although his only formal education was a Civil Engineering Bachelor's degree from College of Engineering, Guindy, University of Madras. Before his death in 1988, at 57 years old, he was the only one to have received both the Homi Bhabha Fellowship 1967-69 (he spent his time at the Tata Institute of Fundamental Research, Bombay, and at the Massachusetts Institute of Technology, Cambridge, Massachusetts doing research in Groundwater modeling) and the Jawaharlal Nehru Fellowship 1975-77, two of the country's top research awards.
During the period of Jawaharlal Nehru Fellowship he created the first comprehensive 20 volume hydrological atlas of Tamil Nadu State of India including mathematical models, details of hydraulic structures, among others. He developed also the double bounded probability density function (Kumaraswamy distribution), a probability density function suitable for physical variables that are usually bounded. This distribution is in use in electrical, civil, mechanical, and financial engineering applications. He gave the first practical hard rock well theory that won him the Gold Medal award from Indian Geohydrologists in 1974. He worked also as a design and construction engineer of two major industrial works, namely, the Tiruchirappalli Boiler Plant, and the Tuticori
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https://en.wikipedia.org/wiki/Ester%20%28disambiguation%29
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An ester is a functional group in organic chemistry; specifically a chemical compound derived from an acid in which at least one hydroxyl group is replaced by alkoxy group.
Ester may also refer to:
Food additives and chemistry
Ester C, ascorbyl palmitate, used as an antioxidant food additive
Ester gum, or Ester of wood rosin, a food additive used as an emulsifier and stabiliser
Ester pyrolysis, a vacuum pyrolysis reaction
Geography
Ester, Alaska, a town
Ester Camp Historic District, Alaska
Ester Mountains in Germany
Ester (Castro Daire), parish in Castro Daire, Portugal
People
Ester, the Italian, Spanish, and Portuguese version of the female given name Esther
Laura Ester (1990), Spanish female water polo goalkeeper
Pauline Ester, French singer born Sabrina Ocon in 1963
Peter Ester (born 1953), Dutch sociologist and politician
Sofia Ester (born 1978), Portuguese author
Ester (footballer) (born 1982), Brazilian footballer
Music
Classical
Ester (Stradella), an Italian oratorio by Alessandro Stradella
Ester, an Italian oratorio by Carlo Arrigoni Vienna 1737–38
Ester, an Italian oratorio by Carl Ditters von Dittersdorf
Ester, a Hebrew-language oratorio by C. G. Lidarti
Popular
Ester, an album by Trailer Trash Tracys 2012
Other uses
Typhoon Ester (disambiguation)
See also
Esther (disambiguation)
Hadassah (disambiguation)
Estonian feminine given names
Feminine given names
Portuguese feminine given names
Spanish feminine given names
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https://en.wikipedia.org/wiki/Time%20Squared
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Time Squared may refer to:
Time Squared, two graphic novels by Howard Chaykin
"Time Squared" (Star Trek: The Next Generation), the 39th episode of the television series Star Trek: The Next Generation
Time Squared Academy High School, high school specializing in mathematics, engineering, and science
Time Squared (album)
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https://en.wikipedia.org/wiki/Henry%20reaction
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The Henry reaction is a classic carbon–carbon bond formation reaction in organic chemistry. Discovered in 1895 by the Belgian chemist Louis Henry (1834–1913), it is the combination of a nitroalkane and an aldehyde or ketone in the presence of a base to form β-nitro alcohols. This type of reaction is also referred to as a nitroaldol reaction (nitroalkane, aldehyde, and alcohol). It is nearly analogous to the aldol reaction that had been discovered 23 years prior that couples two carbonyl compounds to form β-hydroxy carbonyl compounds known as "aldols" (aldehyde and alcohol). The Henry reaction is a useful technique in the area of organic chemistry due to the synthetic utility of its corresponding products, as they can be easily converted to other useful synthetic intermediates. These conversions include subsequent dehydration to yield nitroalkenes, oxidation of the secondary alcohol to yield α-nitro ketones, or reduction of the nitro group to yield β-amino alcohols.
Many of these uses have been exemplified in the syntheses of various pharmaceuticals including the β-blocker (S)-propranolol, the HIV protease inhibitor Amprenavir (Vertex 478), and construction of the carbohydrate subunit of the anthracycline class of antibiotics, L-Acosamine. The synthetic scheme of the L-Acosamine synthesis can be found in the Examples section of this article.
Mechanism
The Henry reaction begins with the deprotonation of the nitroalkane on the α-carbon position forming a nitronate. The pKa
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https://en.wikipedia.org/wiki/Annus%20mirabilis%20papers
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The annus mirabilis papers (from Latin annus mīrābilis, "miracle year") are the four papers that Albert Einstein published in Annalen der Physik (Annals of Physics), a scientific journal, in 1905. These four papers were major contributions to the foundation of modern physics. They revolutionized science's understanding of the fundamental concepts of space, time, mass, and energy. Because Einstein published these remarkable papers in a single year, 1905 is called his annus mirabilis (miracle year in English or Wunderjahr in German).
The first paper explained the photoelectric effect, which established the energy of the light quanta , and was the only specific discovery mentioned in the citation awarding Einstein the Nobel Prize in Physics.
The second paper explained Brownian motion, which established the Einstein relation and led reluctant physicists to accept the existence of atoms.
The third paper introduced Einstein's theory of special relativity, which used the universal constant speed of light to derive the Lorentz transformations.
The fourth, a consequence of the theory of special relativity, developed the principle of mass–energy equivalence, expressed in the famous equation and which led to the discovery and use of atomic energy decades later.
These four papers, together with quantum mechanics and Einstein's later theory of general relativity, are the foundation of modern physics.
Background
At the time the papers were written, Einstein did not have easy
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https://en.wikipedia.org/wiki/Theoretical%20astronomy
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Theoretical astronomy is the use of analytical and computational models based on principles from physics and chemistry to describe and explain astronomical objects and astronomical phenomena. Theorists in astronomy endeavor to create theoretical models and from the results predict observational consequences of those models. The observation of a phenomenon predicted by a model allows astronomers to select between several alternate or conflicting models as the one best able to describe the phenomena.
Ptolemy's Almagest, although a brilliant treatise on theoretical astronomy combined with a practical handbook for computation, nevertheless includes compromises to reconcile discordant observations with a geocentric model. Modern theoretical astronomy is usually assumed to have begun with the work of Johannes Kepler (1571–1630), particularly with Kepler's laws. The history of the descriptive and theoretical aspects of the Solar System mostly spans from the late sixteenth century to the end of the nineteenth century.
Theoretical astronomy is built on the work of observational astronomy, astrometry, astrochemistry, and astrophysics. Astronomy was early to adopt computational techniques to model stellar and galactic formation and celestial mechanics. From the point of view of theoretical astronomy, not only must the mathematical expression be reasonably accurate but it should preferably exist in a form which is amenable to further mathematical analysis when used in specific problem
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https://en.wikipedia.org/wiki/Alexa%20Fluor
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The Alexa Fluor family of fluorescent dyes is a series of dyes invented by Molecular Probes, now a part of Thermo Fisher Scientific, and sold under the Invitrogen brand name. Alexa Fluor dyes are frequently used as cell and tissue labels in fluorescence microscopy and cell biology. Alexa Fluor dyes can be conjugated directly to primary antibodies or to secondary antibodies to amplify signal and sensitivity or other biomolecules.
The excitation and emission spectra of the Alexa Fluor series cover the visible spectrum and extend into the infrared. The individual members of the family are numbered according roughly to their excitation maxima in nanometers.
History
Richard and Rosaria Haugland, the founders of Molecular Probes, are well known in biology and chemistry for their research into fluorescent dyes useful in biological research applications. At the time that Molecular Probes was founded, such products were largely unavailable commercially. A number of fluorescent dyes that are now widely used were discovered and developed in the laboratories of Molecular Probes.—dyes such as Texas Red, Cascade Blue, Oregon Green, Marina Blue, and the Alexa Fluor family. The most famous of these, the Alexa Fluor family of dyes, were designed to improve upon properties of previously developed biological fluorescent dye families, and solve some of the issues that they possessed. The Alexa Fluor dyes were named after Alex Haugland, son of Richard and Rosaria Haugland.
Molecular Probes w
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https://en.wikipedia.org/wiki/Annihilation%20%28disambiguation%29
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Annihilation, in physics, is an effect that occurs when a particle collides with an antiparticle.
Annihilation may also refer to:
Arts, entertainment, and media
Comics
Annihilation (comics), a Marvel Comics 2006 event featuring several cosmic characters
Annihilation: Conquest, a 2007 series featuring similar themes and marketed as a sequel of the above comic book series
Literature
Annihilation (Forgotten Realms novel), a 2004 novel by Philip Athans set in the Forgotten Realms universe
Annihilation (VanderMeer novel), a 2014 novel by Jeff VanderMeer and the first entry in the Southern Reach Trilogy
Films
Annihilation (film), a 2018 film based on VanderMeer's novel
Mortal Kombat Annihilation, the sequel to Mortal Kombat
Games
Annihilation, a map pack for Call of Duty: Black Ops
Music
Annihilation (album), 2001 Rebaelliun album
"Annihilate" (song), a 2023 song by Metro Boomin, Swae Lee, Lil Wayne and Offset
"Annihilation", a song from the album Dehumanization by Crucifix
Law
Family annihilation, the act of killing everyone in a family.
Logic and mathematics
Annihilation, an operation in classical logic
Creation and annihilation operators, mathematical operators utilized in the field of quantum mechanics
See also
"Annihilated", an episode from Law & Order: Special Victims Unit (season 8)
Annihilating element
Annihilationism, a minority Christian doctrine that the unsaved cease to exist rather than suffering conscious eternal torment in Hell
Annihilator (disambigu
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https://en.wikipedia.org/wiki/David%20S.%20Touretzky
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David S. Touretzky is a research professor in the Computer Science Department and the Center for the Neural Basis of Cognition at Carnegie Mellon University. He received a BA in Computer Science at Rutgers University in 1978, and earned a master's degree and a Ph.D. (1984) in Computer Science at Carnegie Mellon University. Touretzky has worked as an Internet activist in favor of freedom of speech, especially what he perceives as abuse of the legal system by government and private authorities. He is a notable critic of Scientology.
Research
Touretzky's research interests lie in the fields of artificial intelligence, computational neuroscience, and learning. This includes machine learning and animal learning, and in particular neural representation of space in rodents (e.g., in the hippocampus) and in robots. In 2006, he was recognized as a Distinguished Scientist by the Association for Computing Machinery.
Criticism of Scientology
Since the 1990s, Touretzky has worked to expose the actions of the Church of Scientology. He sees the actions of the organization as a threat to free speech, and he has taken a prominent part in Internet-based activism to oppose it, also appearing regularly as a critic in radio and print. He has also worked to expose what he sees as dangerous and potentially life-threatening treatments provided by Narconon, the Scientology-based drug rehabilitation program. He maintains a Web site named Stop Narconon, which archives media articles critical of the
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https://en.wikipedia.org/wiki/Homotopy%20category
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In mathematics, the homotopy category is a category built from the category of topological spaces which in a sense identifies two spaces that have the same shape. The phrase is in fact used for two different (but related) categories, as discussed below.
More generally, instead of starting with the category of topological spaces, one may start with any model category and define its associated homotopy category, with a construction introduced by Quillen in 1967. In this way, homotopy theory can be applied to many other categories in geometry and algebra.
The naive homotopy category
The category of topological spaces Top has objects the topological spaces and morphisms the continuous maps between them. The older definition of the homotopy category hTop, called the naive homotopy category for clarity in this article, has the same objects, and a morphism is a homotopy class of continuous maps. That is, two continuous maps f: X → Y are considered the same in the naive homotopy category if one can be continuously deformed to the other. There is a functor from Top to hTop that sends spaces to themselves and morphisms to their homotopy classes. A map f: X → Y is called a homotopy equivalence if it becomes an isomorphism in the naive homotopy category.
Example: The circle S1, the plane R2 minus the origin, and the Möbius strip are all homotopy equivalent, although these topological spaces are not homeomorphic.
The notation [X,Y] is often used for the set of morphisms from a space
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https://en.wikipedia.org/wiki/Pacific%20saury
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The Pacific saury (Cololabis saira) is species of fish in the family Scomberesocidae. Saury is a seafood in several East Asian cuisines and is also known by the name mackerel pike.
Biology
Saury is a fish with a small mouth, an elongated body, a series of small finlets between the dorsal and anal fins, and a small forked tail. The fish's color is dark green to blue on the dorsal surface, silvery below, and there are small, bright blue blotches distributed randomly on the sides.
It is about 25-30 cm long when caught, but it can grow up to 40 cm long and is about 180 grams when caught in the autumn. Saury will be at most four years old. Saury is a pelagic fish and wants to stay close to the surface and is caught there, but it can also be down to a depth of up to 230 m. When saury is escaping from predators, it floats on the surface and is similar to other fish within the genus.
These pelagic schooling fish are found in the North Pacific, from China, Korea and Japan eastward to the Gulf of Alaska and southward to subtropical Mexico, preferring temperatures around 15 – 18 °C. Pacific saury is usually found near the surface (though they may have a depth range of 0 – 230 m).
The Pacific saury is a highly migratory species. Adults are generally found offshore, near the surface of the ocean, in schools. Juveniles associate with drifting seaweed. Pacific saury are oviparous. Eggs are attached to floating objects, such as seaweed, via filaments on the shell surface.
The saury f
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https://en.wikipedia.org/wiki/Carreau%20fluid
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Carreau fluid in physics is a type of generalized Newtonian fluid where viscosity, , depends upon the shear rate, , by the following equation:
Where: , , and are material coefficients.
= viscosity at zero shear rate (Pa.s)
= viscosity at infinite shear rate (Pa.s)
= characteristic time (s)
= power index
The dynamics of fluid motions is an important area of physics, with many important and commercially significant applications.
Computers are often used to calculate the motions of fluids, especially when the applications are of a safety critical nature.
Carreau Fluid Shear Rates
At low shear rate () a Carreau fluid behaves as a Newtonian fluid with viscosity .
At intermediate shear rates (), a Carreau fluid behaves as a Power-law fluid.
At high shear rate, which depends on the power index and the infinite shear-rate viscosity , a Carreau fluid behaves as a Newtonian fluid again with viscosity .
Origin of Carreau Fluid Model
The model was first proposed by Pierre Carreau.
See also
Navier-Stokes equations
Fluid
Cross fluid
Power-law fluid
Generalized Newtonian fluid
References
Kennedy, P. K., Flow Analysis of Injection Molds. New York. Hanser.
Non-Newtonian fluids
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https://en.wikipedia.org/wiki/Shear%20rate
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In physics, shear rate is the rate at which a progressive shearing deformation is applied to some material.
Simple shear
The shear rate for a fluid flowing between two parallel plates, one moving at a constant speed and the other one stationary (Couette flow), is defined by
where:
is the shear rate, measured in reciprocal seconds;
is the velocity of the moving plate, measured in meters per second;
is the distance between the two parallel plates, measured in meters.
Or:
For the simple shear case, it is just a gradient of velocity in a flowing material. The SI unit of measurement for shear rate is s−1, expressed as "reciprocal seconds" or "inverse seconds". However, when modelling fluids in 3D, it is common to consider a scalar value for the shear rate by calculating the second invariant of the strain-rate tensor
.
The shear rate at the inner wall of a Newtonian fluid flowing within a pipe is
where:
is the shear rate, measured in reciprocal seconds;
is the linear fluid velocity;
is the inside diameter of the pipe.
The linear fluid velocity is related to the volumetric flow rate by
where is the cross-sectional area of the pipe, which for an inside pipe radius of is given by
thus producing
Substituting the above into the earlier equation for the shear rate of a Newtonian fluid flowing within a pipe, and noting (in the denominator) that :
which simplifies to the following equivalent form for wall shear rate in terms of volumetric flow rate and inner pipe
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https://en.wikipedia.org/wiki/Sierra%20Nevada%20bighorn%20sheep
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The Sierra Nevada bighorn sheep (Ovis canadensis sierrae) is subspecies of bighorn sheep unique to the Sierra Nevada mountains of California. A 2016 genetics study confirmed significant divergence between the three subspecies of North America's bighorn sheep: Sierra Nevada bighorn sheep, Rocky Mountain bighorn sheep and desert bighorn sheep. Sierra Nevada bighorn sheep were listed as a federally endangered subspecies in 2000. In 2016, over 600 Sierra bighorn remained in the wild. However, in 2023, more recent studies indicate that the population has dropped to approximately half, or 300. This is due to high levels of mountain lion predation combined with heavy snowfall, threatening the species even further.
Physical characteristics
Sierra Nevada bighorn range in color from white to dark brown, with a white rump and dark tail. There is some seasonal change in coloration due to the shedding of a thicker winter layer. Specialized hooves with adhesive soles provide traction in steep rocky terrain. Female bighorn (ewes) can weigh up to and have shorter, narrow horns, while male bighorn (rams) can weigh as much as and have massive, curving horns. The horns of both rams and ewes are composed of a dense layer of keratin covering a core of bone. The Sierra Nevada bighorn sheep's specialized hooves are not only essential for navigating their rocky habitats but also play a crucial role in their mating rituals, where males engage in horn-clashing contests to establish dominance. Thei
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https://en.wikipedia.org/wiki/PZC
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PZC may refer to:
Point of zero charge, a concept relating to the phenomenon of adsorption in physical chemistry
Provinciale Zeeuwse Courant, a Dutch newspaper for the region of Zeeland
Providence Zen Center, the international headquarters for the Kwan Um School of Zen
PZ Cussons, a manufacturer of personal healthcare products and consumer goods
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https://en.wikipedia.org/wiki/Couette%20flow
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In fluid dynamics, Couette flow is the flow of a viscous fluid in the space between two surfaces, one of which is moving tangentially relative to the other. The relative motion of the surfaces imposes a shear stress on the fluid and induces flow. Depending on the definition of the term, there may also be an applied pressure gradient in the flow direction.
The Couette configuration models certain practical problems, like the Earth's mantle and atmosphere, and flow in lightly loaded journal bearings. It is also employed in viscometry and to demonstrate approximations of reversibility.
It is named after Maurice Couette, a Professor of Physics at the French University of Angers in the late 19th century.
Planar Couette flow
Couette flow is frequently used in undergraduate physics and engineering courses to illustrate shear-driven fluid motion. A simple configuration corresponds to two infinite, parallel plates separated by a distance ; one plate translates with a constant relative velocity in its own plane. Neglecting pressure gradients, the Navier–Stokes equations simplify to
where is the spatial coordinate normal to the plates and is the velocity field. This equation reflects the assumption that the flow is unidirectional — that is, only one of the three velocity components is non-trivial. If the lower plate corresponds to , the boundary conditions are and . The exact solution
can be found by integrating twice and solving for the constants using the boundary condit
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https://en.wikipedia.org/wiki/Time-Triggered%20Protocol
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The Time-Triggered Protocol (TTP) is an open computer network protocol for control systems.
It was designed as a time-triggered fieldbus for vehicles and industrial applications. and standardized in 2011 as SAE AS6003 (TTP Communication Protocol). TTP controllers have accumulated over 500 million flight hours in commercial DAL A aviation application, in power generation, environmental and flight controls. TTP is used in FADEC and modular aerospace controls, and flight computers. In addition, TTP devices have accumulated over 1 billion operational hours in SIL4 railway signalling applications.
History
TTP was originally designed at the Vienna University of Technology in the early 1980s. In 1998 TTTech Computertechnik AG took over the development of TTP, providing software and hardware products. TTP communication controller chips and IP are available from sources including austriamicrosystems, ON Semiconductor and ALTERA.
Definition
TTP is a dual-channel 4 - 25 Mbit/s time-triggered field bus. It can operate using one or both channels with maximum data rate of 2x 25 Mbit/s. With replicated data on both channels, redundant communication is supported
As a fault-tolerant time-triggered protocol, TTP provides autonomous fault-tolerant message transport at known times and with minimal jitter by employing a TDMA (Time-Division Multiple Access) strategy on replicated communication channels. TTP offers fault-tolerant clock synchronization that establishes the global time base with
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https://en.wikipedia.org/wiki/Clark%20electrode
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The Clark electrode is an electrode that measures ambient oxygen partial pressure in a liquid using a catalytic platinum surface according to the net reaction:
O2 + 4 e− + 4 H+ → 2 H2O
It improves on a bare platinum electrode by use of a membrane to reduce fouling and metal plating onto the platinum.
History
Leland Clark (Professor of Chemistry, Antioch College, Yellow Springs, Ohio, and Fels Research Institute, Yellow Springs, Ohio) had developed the first bubble oxygenator for use in cardiac surgery. However, when he came to publish his results, his article was refused by the editor since the oxygen tension in the blood coming out from the device could not be measured. This motivated Clark to develop the oxygen electrode.
The electrode, when implanted in vivo, will reduce oxygen and thus required stirring in order to maintain an equilibrium with the environment. Severinghaus improved the design by adding a stirred cuvette in a thermostat. A discrepancy between the measured partial pressure of oxygen (pO2) between blood samples and gaseous mixtures of identical pO2, meant that the modified electrode required calibration; consequently a microtonometer was added to the water thermostat.
Mechanism of action
The electrode compartment is isolated from the reaction chamber by a thin Teflon membrane; the membrane is permeable to molecular oxygen and allows this gas to reach the cathode, where it is electrolytically reduced.
The above reaction requires a steady stream of ele
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https://en.wikipedia.org/wiki/Damodar%20Dharmananda%20Kosambi
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Damodar Dharmananda Kosambi (31 July 1907 – 29 June 1966) was an Indian polymath with interests in mathematics, statistics, philology, history, and genetics. He contributed to genetics by introducing the Kosambi map function. In statistics, he was the first person to develop orthogonal infinite series expressions for stochastic processes via the Kosambi–Karhunen–Loève theorem. He is also well known for his work in numismatics and for compiling critical editions of ancient Sanskrit texts. His father, Dharmananda Damodar Kosambi, had studied ancient Indian texts with a particular emphasis on Buddhism and its literature in the Pali language. Damodar Kosambi emulated him by developing a keen interest in his country's ancient history. He was also a Marxist historian specialising in ancient India who employed the historical materialist approach in his work. He is particularly known for his classic work An Introduction to the Study of Indian History.
He is described as "the patriarch of the Marxist school of Indian historiography". Kosambi was critical of the policies of then prime minister Jawaharlal Nehru, which, according to him, promoted capitalism in the guise of democratic socialism. He was an enthusiast of the Chinese Communist Revolution and its ideals, and was a leading activist in the world peace movement.
Early life
Damodar Dharmananda Kosambi was born at Kosben in Portuguese Goa into a Saraswat Brahmin family to Dharmananda Damodar Kosambi. After a few years of schooli
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https://en.wikipedia.org/wiki/Petrov%20classification
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In differential geometry and theoretical physics, the Petrov classification (also known as Petrov–Pirani–Penrose classification) describes the possible algebraic symmetries of the Weyl tensor at each event in a Lorentzian manifold.
It is most often applied in studying exact solutions of Einstein's field equations, but strictly speaking the classification is a theorem in pure mathematics applying to any Lorentzian manifold, independent of any physical interpretation. The classification was found in 1954 by A. Z. Petrov and independently by Felix Pirani in 1957.
Classification theorem
We can think of a fourth rank tensor such as the Weyl tensor, evaluated at some event, as acting on the space of bivectors at that event like a linear operator acting on a vector space:
Then, it is natural to consider the problem of finding eigenvalues and eigenvectors (which are now referred to as eigenbivectors) such that
In (four-dimensional) Lorentzian spacetimes, there is a six-dimensional space of antisymmetric bivectors at each event. However, the symmetries of the Weyl tensor imply that any eigenbivectors must belong to a four-dimensional subset.
Thus, the Weyl tensor (at a given event) can in fact have at most four linearly independent eigenbivectors.
The eigenbivectors of the Weyl tensor can occur with various multiplicities and any multiplicities among the eigenbivectors indicates a kind of algebraic symmetry of the Weyl tensor at the given event. The different types of Weyl te
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https://en.wikipedia.org/wiki/Eminox
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Eminox Limited is an English firm which designs and manufactures high performance stainless steel exhaust and emission control systems for bus, truck, rail and off-highway vehicles. The company was started in 1978 and is based in Gainsborough, Lincolnshire, England.
The name 'Eminox' is derived from the initials of two founders, Norman Emerson and David Milles, and 'Inox' which refers to "stainless steel".
Products
Eminox's exhaust products include the following:
Diesel Particulate Filter Systems
Fuel Borne Catalyst System
Diesel Oxidation Catalyst Systems
Spark Arrestors
Stainless Steel Stacks
Electronic Monitoring Systems
Selective Catalytic Reduction Systems
History
Eminox was formed on 28 January 1978 in Lincoln, and consisted of David Milles, Norman Emerson and William Murphy. An early order for a redesigned bus exhaust system for the local bus company led to orders from other national bus companies. The aim of the company was to produce an exhaust system that would last for the lifetime of the vehicle, but that would also meet the requirements of the chassis/body configuration as well as the operating conditions.
In early 1979, Nocorrode, a local company that manufactured replacement stainless steel exhaust systems for cars and fire engines, went into receivership. Eminox purchased the company from the receiver, thus tripling its workforce from 5 to 15. With the purchase came Nocorrode's premises in Tillbridge lane, which became the new home for Eminox.
In 1
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https://en.wikipedia.org/wiki/GRASP%20%28SAT%20solver%29
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GRASP is a well known SAT instance solver. It was developed by João Marques Silva, a Portuguese computer science researcher. It stands for Generic seaRch Algorithm for the Satisfiability Problem.
External links
GRASP home page
References
SAT solvers
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https://en.wikipedia.org/wiki/Abraham%20Nemeth
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Abraham Nemeth (October 16, 1918 – October 2, 2013) was an American mathematician. He was professor of mathematics at the University of Detroit Mercy in Detroit, Michigan. Nemeth was blind and is known for developing Nemeth Braille, a system for blind people to read and write mathematics.
Early life
Nemeth was born in New York City on the Lower East Side of Manhattan into a large family of Hungarian Jewish immigrants who spoke Yiddish. He was blind from birth from a combination of macular degeneration and retinitis pigmentosa.
He attended public schools at first but did most of his primary and secondary education at the Jewish Guild for the Blind school in Yonkers, New York. His undergraduate studies were at Brooklyn College where he studied psychology. He earned a Master of Arts degree in psychology from Columbia University.
Nemeth studied mathematics and physics at Brooklyn College. He did not major in mathematics because his academic advisors discouraged him. However, tired of what he felt were unfulfilling jobs at agencies of the blind, and with the encouragement of his first wife Florence, he decided to continue his education in mathematics. He received a Ph.D. in mathematics from Wayne State University.
Academic career
Nemeth taught part-time at various colleges in New York. Though his employers were sometimes reluctant to hire him knowing that he was blind, his reputation grew as it became apparent that he was a capable mathematician and teacher. Nemeth distinguish
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https://en.wikipedia.org/wiki/Cottrell%20atmosphere
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In materials science, the concept of the Cottrell atmosphere was introduced by A. H. Cottrell and B. A. Bilby in 1949 to explain how dislocations are pinned in some metals by boron, carbon, or nitrogen interstitials.
Cottrell atmospheres occur in body-centered cubic (BCC) and face-centered cubic (FCC) materials, such as iron or nickel, with small impurity atoms, such as boron, carbon, or nitrogen. As these interstitial atoms distort the lattice slightly, there will be an associated residual stress field surrounding the interstitial. This stress field can be relaxed by the interstitial atom diffusing towards a dislocation, which contains a small gap at its core (as it is a more open structure), see Figure 1. Once the atom has diffused into the dislocation core the atom will stay. Typically only one interstitial atom is required per lattice plane of the dislocation. The collection of solute atoms around the dislocation core due to this process is the Cottrell atmosphere.
Influence on Mechanical Behavior
The collection of solute atoms at the dislocation relieves the stresses associated with the dislocation, which lowers the energy of the dislocation's presence. Thus, moving the dislocation out of this Cottrell atmosphere constitutes an increase in energy, so it is not favorable for the dislocation to move forward in the crystal. As a result, the dislocation is effectively pinned by the Cottrell atmosphere.
Once a dislocation has become pinned, a large force is required to u
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https://en.wikipedia.org/wiki/Oxycation
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In chemistry, an oxycation is a polyatomic ion with a positive charge that contains oxygen.
Examples
Dioxygenyl ion,
Nitrosonium ion,
Nitronium ion,
Vanadyl ion, VO2+, a very stable oxycation
Uranyl ion, , all natural U6+ occurs in this form
Zirconyl ion, as a tetramer of [Zr(OH)2]2+
See category for a bigger list.
See also
Oxyanion
List of aqueous ions by element
External links
Cations
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https://en.wikipedia.org/wiki/Race%20%28biology%29
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In biological taxonomy, race is an informal rank in the taxonomic hierarchy for which various definitions exist. Sometimes it is used to denote a level below that of subspecies, while at other times it is used as a synonym for subspecies. It has been used as a higher rank than strain, with several strains making up one race. Races may be genetically distinct populations of individuals within the same species, or they may be defined in other ways, e.g. geographically, or physiologically. Genetic isolation between races is not complete, but genetic differences may have accumulated that are not (yet) sufficient to separate species.
The term is recognized by some, but not governed by any of the formal codes of biological nomenclature. Taxonomic units below the level of subspecies are not typically applied to animals.
Other terms
In botany, the Latin words stirps and proles were traditionally used, and proles was recommended in the first botanical Code of Nomenclature, published in 1868.
Definitional approaches
Races are defined according to any identifiable characteristic, including gene frequencies. "Race differences are relative, not absolute". Adaptive differences that distinguish races can accumulate even with substantial gene flow and clinal (rather than discrete) habitat variation. Hybrid zones between races are semi-permeable barriers to gene flow, see for example the chromosome races of the Auckland tree wētā.
The term race has also historically been used in relatio
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https://en.wikipedia.org/wiki/Coincidence%20point
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In mathematics, a coincidence point (or simply coincidence) of two functions is a point in their common domain having the same image.
Formally, given two functions
we say that a point x in X is a coincidence point of f and g if f(x) = g(x).
Coincidence theory (the study of coincidence points) is, in most settings, a generalization of fixed point theory, the study of points x with f(x) = x. Fixed point theory is the special case obtained from the above by letting X = Y and taking g to be the identity function.
Just as fixed point theory has its fixed-point theorems, there are theorems that guarantee the existence of coincidence points for pairs of functions. Notable among them, in the setting of manifolds, is the Lefschetz coincidence theorem, which is typically known only in its special case formulation for fixed points.
Coincidence points, like fixed points, are today studied using many tools from mathematical analysis and topology. An equaliser is a generalization of the coincidence set.
References
Mathematical analysis
Topology
Fixed points (mathematics)
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