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https://en.wikipedia.org/wiki/Seifert%20conjecture
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In mathematics, the Seifert conjecture states that every nonsingular, continuous vector field on the 3-sphere has a closed orbit. It is named after Herbert Seifert. In a 1950 paper, Seifert asked if such a vector field exists, but did not phrase non-existence as a conjecture. He also established the conjecture for perturbations of the Hopf fibration.
The conjecture was disproven in 1974 by Paul Schweitzer, who exhibited a counterexample. Schweitzer's construction was then modified by Jenny Harrison in 1988 to make a counterexample for some . The existence of smoother counterexamples remained an open question until 1993 when Krystyna Kuperberg constructed a very different counterexample. Later this construction was shown to have real analytic and piecewise linear versions.
References
V. Ginzburg and B. Gürel, A -smooth counterexample to the Hamiltonian Seifert conjecture in , Ann. of Math. (2) 158 (2003), no. 3, 953–976
P. A. Schweitzer, Counterexamples to the Seifert conjecture and opening closed leaves of foliations, Annals of Mathematics (2) 100 (1974), 386–400.
H. Seifert, Closed integral curves in 3-space and isotopic two-dimensional deformations, Proc. Amer. Math. Soc. 1, (1950). 287–302.
Further reading
K. Kuperberg, Aperiodic dynamical systems. Notices Amer. Math. Soc. 46 (1999), no. 9, 1035–1040.
Differential topology
Disproved conjectures
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https://en.wikipedia.org/wiki/GNS%20Science
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GNS Science (), officially registered as the Institute of Geological and Nuclear Sciences Limited, is a New Zealand Crown Research Institute. It focuses on geology, geophysics (including seismology and volcanology), and nuclear science (particularly ion-beam technologies, isotope science and carbon dating).
GNS Science was known as the Institute of Geological and Nuclear Sciences (IGNS) from 1992 to 2005. Originally part of the New Zealand Government's Department of Scientific and Industrial Research (DSIR), it was established as an independent organisation when the Crown Research Institutes were set up in 1992.
As well as undertaking basic research, and operating the national geological hazards monitoring network (GeoNet) and the National Isotope Centre (NIC),
GNS Science contracts its services to various private groups (notably energy companies) both in New Zealand and overseas, as well as to central and local government agencies, to provide scientific advice and information.
GNS Science has its head office in Avalon, Lower Hutt, with other facilities in Gracefield, Dunedin, Wairakei, Auckland and Tokyo.
References
External links
GNS Science
GeoNet Hazards Monitoring Network
Crown Research Institutes of New Zealand
Science and technology in New Zealand
National geological agencies
Nuclear technology in New Zealand
Earth sciences
Earth science research institutes
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https://en.wikipedia.org/wiki/Rare
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Rare may refer to:
Rare, a particular temperature of meat
Something infrequent or scarce, see Scarcity
Rare species, a conservation category in biology designating the scarcity of an organism and implying a threat to its viability
Rare or RARE may also refer to:
Acronyms
Ram Air Rocket Engine, a U.S. Navy program of the 1950s
Ronne Antarctic Research Expedition
Music
Rare (Northern Irish band), a 1990s trip hop group
Rare (Serbian band), an alternative rock band
Albums
Rare (Asia album), 1999
Rare (David Bowie album), 1982
Rare (Hundredth album), 2017
Rare (Selena Gomez album) or the title song (see below), 2020
Rare!, by Crack the Sky, 1994
Rare, Vol. 1, by Ultravox, 1993
Rare, Vol. 2, by Ultravox, 1994
Rare: The Collected B-Sides 1989–1993, by Moby, 1996
Rare, by Xiu Xiu, 2012
Songs
"Rare" (Gwen Stefani song), 2016
"Rare" (Selena Gomez song), 2020
"Rare", by Man Overboard from Man Overboard, 2011
Organizations
Rare (company), a British video game development studio
Réseaux Associés pour la Recherche Européenne, a computer networking organisation known since 1994 as TERENA
Rare (conservation organization), an environmentalist group
Rare (news website), a U.S.-based website
People
Vanessa Rare, New Zealand film and television actress, film screenwriter and director
See also
Rarity (disambiguation)
Rarities (disambiguation)
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https://en.wikipedia.org/wiki/Cochin%20University%20College%20of%20Engineering%20Kuttanad
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Campus at Kuttanad was established in 1999 under the aegis of the University. It is situated in a serene and beautiful 42-acre campus in Pulincunnoo, Kannady, Kuttanad, the rice bowl of Kerala in Alappuzha district. It offers B.Tech programs in Civil Engineering, Computer Science & Engineering, Electrical & Electronics Engineering, Electronics and Communication Engineering, Information Technology, Mechanical Engineering and M.C.A. Many of the faculty members have refined and sharpened their knowledge through rigorous research activities and published their findings in various national and international science and technical journals. The University raised the status of college to that of a Research Center in 2017. There are 42 Research Scholars working for their PhD under nine research supervisors in the College. The faculty under which the PhD programs are offered are Faculty of Engineering, Faculty of Technology and Faculty of Social Sciences under the Cochin University of Science and Technology.
The college is situated on the outskirts of Pulincunnu Panchayat, near the village of Kannady. The college attracts students from all parts of India, particularly from Kerala, Uttar Pradesh, Bihar, West Bengal, Jharkhand and Delhi.
Admission
Admissions are based on an All India Entrance Examination known as Common Admission Test (CAT) conducted by the University which includes papers for admission to undergraduate courses. The College has got students from all over the country.
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https://en.wikipedia.org/wiki/Soil%20mechanics
|
Soil mechanics is a branch of soil physics and applied mechanics that describes the behavior of soils. It differs from fluid mechanics and solid mechanics in the sense that soils consist of a heterogeneous mixture of fluids (usually air and water) and particles (usually clay, silt, sand, and gravel) but soil may also contain organic solids and other matter. Along with rock mechanics, soil mechanics provides the theoretical basis for analysis in geotechnical engineering, a subdiscipline of civil engineering, and engineering geology, a subdiscipline of geology. Soil mechanics is used to analyze the deformations of and flow of fluids within natural and man-made structures that are supported on or made of soil, or structures that are buried in soils. Example applications are building and bridge foundations, retaining walls, dams, and buried pipeline systems. Principles of soil mechanics are also used in related disciplines such as geophysical engineering, coastal engineering, agricultural engineering, hydrology and soil physics.
This article describes the genesis and composition of soil, the distinction between pore water pressure and inter-granular effective stress, capillary action of fluids in the soil pore spaces, soil classification, seepage and permeability, time dependent change of volume due to squeezing water out of tiny pore spaces, also known as consolidation, shear strength and stiffness of soils. The shear strength of soils is primarily derived from friction between
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https://en.wikipedia.org/wiki/Bill%20Roscoe
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Andrew William Roscoe is a Scottish computer scientist. He was Head of the Department of Computer Science, University of Oxford from 2003 to 2014, and is a Professor of Computer Science. He is also a Fellow of University College, Oxford.
Education and career
Roscoe was born in Dundee, Scotland. He studied for a degree in mathematics at University College, Oxford, from 1975 to 1978, graduating with the top mark for his year in the university. He went on to work at the Computing Laboratory and received his DPhil in 1982. He was appointed Tutorial Fellow at University College in 1983 and served as Senior Tutor from 1993 to 1997. He was head of the Department of Computer Science 2003-08 and 2009–14.
Research
Professor Roscoe works in the area of concurrency theory, in particular the semantic underpinning of Communicating Sequential Processes (CSP) and the associated occam programming language with Sir Tony Hoare. He co-founded Formal Systems (Europe) Limited and worked on the algorithms for the Failures-Divergence Refinement (FDR) tool.
References
External links
Bill Roscoe home page
Living people
People from Dundee
People educated at the High School of Dundee
Alumni of University College, Oxford
Scottish computer scientists
Members of the Department of Computer Science, University of Oxford
Formal methods people
Fellows of University College, Oxford
Scottish scholars and academics
1956 births
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https://en.wikipedia.org/wiki/CLP
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CLP may stand for:
Biology
CLP protease family, a family of proteolytic enzymes
Endopeptidase Clp, an enzyme complex
ATP-dependent Clp protease proteolytic subunit, a catalytic subunit of the Clp complex (encoded by the CLPP gene in humans)
Businesses
CLP Group, formerly China Light and Power
Connecticut Light and Power Company
Computing, mathematics, and technology
Cell Loss Priority
COIN-OR Linear Program Solver
Communication Linking Protocol
Congruence lattice problem
Constraint Logic Programming
Constraint logic programming (Real)
Control Language Programming, an IBM programming language used on the System/38, AS/400, and successors
Convergent Linux Platform
Political parties
Canadian Labour Party, former
Communist Labor Party of America, predecessors of the Communist Party USA
Constituency Labour Party, a sub-division of the British Labour Party representing a single UK constituency
Country Liberal Party, Northern Territory, Australia
Certifications
Certificate in Legal Practice (Malaysia)
Certified Landscape Professional
Transport
Clapham High Street railway station, London, National Rail station code CLP
Clarks Point Airport, Alaska, IATA airport code CLP
Other uses
AOL Community Leader Program
CLP Regulation on classification, labelling and packaging of chemicals, EU
Chilean peso, the currency of Chile by ISO 4217 code
Cleft lip and palate
Cloppenburg (district), Germany
Copa de la Liga Profesional, an Argentine football competit
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https://en.wikipedia.org/wiki/NASA%20Astrobiology%20Institute
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The NASA Astrobiology Institute (NAI) was established in 1998 by the National Aeronautics and Space Administration (NASA) "to develop the field of astrobiology and provide a scientific framework for flight missions." In December 2019 the institute's activities were suspended.
The NAI is a virtual, distributed organization that integrates astrobiology research and training programs in concert with the national and international science communities.
History
Although NASA had explored the idea of forming an astrobiology institute in the past, when the Viking biological experiments returned negative results for life on Mars, the public lost interest and federal funds for exobiology dried up. In 1996, the announcement of possible traces of ancient life in the Allan Hills 84001 meteorite from Mars led to new interest in the subject. At the same time, NASA developed the Origins Program, broadening its reach from exobiology to astrobiology, the study of the origin, evolution, distribution, and future of life in the universe.
In 1998, $9 million was set aside to fund the NASA Astrobiology Institute (NAI), an interdisciplinary research effort using the expertise of different scientific research institutions and universities from across the country, centrally linked to Ames Research Center in Mountain View, California. Gerald Soffen former Project Scientist with the Viking program, helped coordinate the new institute. In May, NASA selected eleven science teams, each with a Principal
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https://en.wikipedia.org/wiki/Branched%20surface
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In mathematics, a branched surface is a generalization of both surfaces and train tracks.
Definition
A surface is a space that locally looks like ℝ² (up to homeomorphism).
Consider, however, the space obtained by taking the quotient of two copies A,B of ℝ² under the identification of a closed half-space of each with a closed half-space of the other. This will be a surface except along a single line. Now, pick another copy C of ℝ and glue it and A together along halfspaces so that the singular line of this gluing is transverse in A to the previous singular line.
Call this complicated space K. A branched surface is a space that is locally modeled on K.
Weight
A branched manifold can have a weight assigned to various of its subspaces; if this is done, the space is often called a weighted branched manifold. Weights are non-negative real numbers and are assigned to subspaces N that satisfy the following:
N is open.
N does not include any points whose only neighborhoods are the quotient space described above.
N is maximal with respect to the above two conditions.
That is, N is a component of the branched surface minus its branching set. Weights are assigned so that if a component branches into two other components, then the sum of the weights of the two unidentified halfplanes of that neighborhood is the weight of the identified halfplane.
See also
Branched covering
Branched manifold
References
Geometric topology
3-manifolds
Generalized manifolds
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https://en.wikipedia.org/wiki/Branched%20manifold
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In mathematics, a branched manifold is a generalization of a differentiable manifold which may have singularities of very restricted type and admits a well-defined tangent space at each point. A branched n-manifold is covered by n-dimensional "coordinate charts", each of which involves one or several "branches" homeomorphically projecting into the same differentiable n-disk in Rn. Branched manifolds first appeared in the dynamical systems theory, in connection with one-dimensional hyperbolic attractors constructed by Smale and were formalized by R. F. Williams in a series of papers on expanding attractors. Special cases of low dimensions are known as train tracks (n = 1) and branched surfaces (n = 2) and play prominent role in the geometry of three-manifolds after Thurston.
Definition
Let K be a metrizable space, together with:
a collection {Ui} of closed subsets of K;
for each Ui, a finite collection {Dij} of closed subsets of Ui;
for each i, a map πi: Ui → Din to a closed n-disk of class Ck in Rn.
These data must satisfy the following requirements:
∪j Dij = Ui and ∪i Int Ui = K;
the restriction of πi to Dij is a homeomorphism onto its image πi(Dij) which is a closed class Ck n-disk relative to the boundary of Din;
there is a cocycle of diffeomorphisms {αlm} of class Ck (k ≥ 1) such that πl = αlm · πm when defined. The domain of αlm is πm(Ul ∩ Um).
Then the space K is a branched n-manifold of class Ck.
The standard machinery of differential topology can be
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https://en.wikipedia.org/wiki/Train%20track%20%28mathematics%29
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In the mathematical area of topology, a train track is a family of curves embedded on a surface, meeting the following conditions:
The curves meet at a finite set of vertices called switches.
Away from the switches, the curves are smooth and do not touch each other.
At each switch, three curves meet with the same tangent line, with two curves entering from one direction and one from the other.
The main application of train tracks in mathematics is to study laminations of surfaces, that is, partitions of closed subsets of surfaces into unions of smooth curves. Train tracks have also been used in graph drawing.
Train tracks and laminations
A lamination of a surface is a partition of a closed subset of the surface into smooth curves. The study of train tracks was originally motivated by the following observation: If a generic lamination on a surface is looked at from a distance by a myopic person, it will look like a train track.
A switch in a train track models a point where two families of parallel curves in the lamination merge to become a single family, as shown in the illustration. Although the switch consists of three curves ending in and intersecting at a single point, the curves in the lamination do not have endpoints and do not intersect each other.
For this application of train tracks to laminations, it is often important to constrain the shapes that can be formed by connected components of the surface between the curves of the track. For instance, Penner and Har
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https://en.wikipedia.org/wiki/Angular%20momentum%20coupling
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In quantum mechanics, angular momentum coupling is the procedure of constructing eigenstates of total angular momentum out of eigenstates of separate angular momenta. For instance, the orbit and spin of a single particle can interact through spin–orbit interaction, in which case the complete physical picture must include spin–orbit coupling. Or two charged particles, each with a well-defined angular momentum, may interact by Coulomb forces, in which case coupling of the two one-particle angular momenta to a total angular momentum is a useful step in the solution of the two-particle Schrödinger equation.
In both cases the separate angular momenta are no longer constants of motion, but the sum of the two angular momenta usually still is. Angular momentum coupling in atoms is of importance in atomic spectroscopy. Angular momentum coupling of electron spins is of importance in quantum chemistry. Also in the nuclear shell model angular momentum coupling is ubiquitous.
In astronomy, spin–orbit coupling reflects the general law of conservation of angular momentum, which holds for celestial systems as well. In simple cases, the direction of the angular momentum vector is neglected, and the spin–orbit coupling is the ratio between the frequency with which a planet or other celestial body spins about its own axis to that with which it orbits another body. This is more commonly known as orbital resonance. Often, the underlying physical effects are tidal forces.
General theory an
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https://en.wikipedia.org/wiki/Skipping
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Skipping may refer to:
A hopping gait that comes naturally to children
A game or form of exercise using a skipping rope
Exon skipping, in molecular biology
Stone skipping, throwing a stone so that it bounces off the surface of water
String skipping, a guitar-playing technique
Snowmobile skipping, a sport where drivers hydroplane snowmobiles on lakes or rivers
British slang for dumpster diving
an episode of the television series Teletubbies
a song by the band Associates from their 1982 album Sulk
Truancy
See also
Skip (disambiguation)
Oswald Skippings (born 1953), former Chief Minister of the Turks and Caicos Islands
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https://en.wikipedia.org/wiki/Euler%20brick
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In mathematics, an Euler brick, named after Leonhard Euler, is a rectangular cuboid whose edges and face diagonals all have integer lengths. A primitive Euler brick is an Euler brick whose edge lengths are relatively prime. A perfect Euler brick is one whose space diagonal is also an integer, but such a brick has not yet been found.
Definition
The definition of an Euler brick in geometric terms is equivalent to a solution to the following system of Diophantine equations:
where are the edges and are the diagonals.
Properties
If is a solution, then is also a solution for any . Consequently, the solutions in rational numbers are all rescalings of integer solutions. Given an Euler brick with edge-lengths , the triple constitutes an Euler brick as well.
Exactly one edge and two face diagonals of a primitive Euler brick are odd.
At least two edges of an Euler brick are divisible by 3.
At least two edges of an Euler brick are divisible by 4.
At least one edge of an Euler brick is divisible by 11.
Examples
The smallest Euler brick, discovered by Paul Halcke in 1719, has edges and face diagonals . Some other small primitive solutions, given as edges — face diagonals , are below:
{| style="border-collapse:collapse;text-align:right;white-space:nowrap;"
|(|| 85,|| 132,|| 720||) — (|| 157,|| 725,|| 732||)
|-
|(||140,|| 480,|| 693||) — (|| 500,|| 707,|| 843||)
|-
|(||160,|| 231,|| 792||) — (|| 281,|| 808,|| 825||)
|-
|(||187,||1020,||1584||) — (||1037,||1595,||1884
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https://en.wikipedia.org/wiki/Portia
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Portia may refer to:
Biology
Portia (spider), a genus of jumping spiders
Anaea troglodyta or Portia, a brush-footed butterfly
Portia tree, a plant native to Polynesia
Other uses
Portia (moon), a moon of Uranus
Portia Club, a women's club in Payette, Idaho/USA
Portia, Missouri, a community in the United States
PORTIA portfolio-management software from Thomson Financial
HMS Lennox (1914) or HMS Portia, a Laforey-class destroyer launched in 1914
People with the given name
Portia Arthur (born 1990), Ghanaian author, writer and reporter
Porcia Catonis, the wife of Roman senator Marcus Junius Brutus (fictionalized as a character in William Shakespeare's play Julius Caesar as "Portia")
Portia Dawson, American actress
Portia de Rossi or Portia DeGeneres, Australian-born actress
Portia Doubleday, American actress
Portia Geach (1873–1959), Australian artist and feminist
Portia Holman (1903–1983), Australian child psychiatrist
Portia Mansfield (1887–1979), American dance educator and choreographer
Portia Robinson (1926–2023), Australian historian
Portia Simpson-Miller, political leader of Jamaica's People's National Party and Prime Minister of Jamaica
Portia White, Canadian singer
Portia Zvavahera (born 1985), Zimbabwean painter
Portia, pen name of Abigail Adams (1744-1818)
Portia, pen name of Grizelda Elizabeth Cottnam Tonge (1803-1825)
Fictional
Portia (The Merchant of Venice), a character in William Shakespeare's play The Merchant of Venice
Portia Quayne, the protagonist in The
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https://en.wikipedia.org/wiki/Theodor%20Grotthuss
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Freiherr Christian Johann Dietrich Theodor von Grotthuss (20 January 1785 – 26 March 1822) was a Baltic German scientist known for establishing the first theory of electrolysis in 1806 and formulating the first law of photochemistry in 1817. His theory of electrolysis is considered the first description of the so-called Grotthuss mechanism.
Life and work
Grotthuss was born in 1785 in Leipzig, Electorate of Saxony, Holy Roman Empire, during an extended stay of his parents away from their home in northern Grand Duchy of Lithuania. He showed interest in natural sciences and went to study first in Leipzig and later in Paris at the École Polytechnique. Several renowned scientists taught at the École Polytechnique at that time, including Antoine François, comte de Fourcroy, Claude Louis Berthollet and Louis Nicolas Vauquelin.
Because of some tensions in the relations between Russia and France, Grotthuss had to leave for Italy where he stayed at Naples for one year. The discovery of the first electric cell in 1800 by Alessandro Volta provided the scientists a source of electricity which was used in various laboratory experiments around Europe. The electrolysis of water, acids and salt solutions was reported, but a good explanation was missing. Grotthuss actively contributed to this area both in terms of electrolysis experiments and their interpretation. During his stay in Italy, he published his work on electrolysis in 1806. His idea that the charge is not transported by the move
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https://en.wikipedia.org/wiki/Ga%C3%A9tan%20Soucy
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Gaétan Soucy (21 October 1958 – 9 July 2013) was a Canadian novelist and professor.
Life
Born in Montreal, Quebec, Soucy studied physics at Université de Montréal, completed a master's degree in philosophy, and studied Japanese language and literature at McGill University.
Soucy has written four novels. His first two, L'Immaculée conception (translated as The Immaculate Conception by Lazer Lederhendler) and L'Acquittement (translated as Atonement by Sheila Fischman) are extraordinary, dark and baroque works. His third novel, La petite fille qui aimait trop les allumettes (translated as The Little Girl Who Was Too Fond of Matches by Fischman) caused a sensation in Quebec and was immediately translated into more than ten languages. His fourth novel, Music-Hall!, was published in 2002, and translated as Vaudeville! by Fischman.
La petite fille qui aimait trop les allumettes was chosen for inclusion in the French version of Canada Reads, broadcast on Radio-Canada in 2004, where it was defended by actor, film director, screenwriter, and musician Micheline Lanctôt.
He died on 9 July 2013 in Montreal of a heart attack.
Awards and recognition
Nominated for the Prix Renaudot, for La petite fille qui aimait trop les allumettes
Prix Ringuet from the Académie des lettres du Québec, for La petite fille qui aimait trop les allumettes
Prix du grand public La Presse/Salon du livre de Montréal, for La petite fille qui aimait trop les allumettes
The Immaculate Conception, shortlisted for
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https://en.wikipedia.org/wiki/Bond%20order
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In chemistry, bond order is a formal measure of the multiplicity of a covalent bond between two atoms. As introduced by Linus Pauling, bond order is defined as the difference between the numbers of electron pairs in bonding and antibonding molecular orbitals.
Bond order gives a rough indication of the stability of a bond. Isoelectronic species have the same bond order.
Examples
The bond order itself is the number of electron pairs (covalent bonds) between two atoms. For example, in diatomic nitrogen N≡N, the bond order between the two nitrogen atoms is 3 (triple bond). In acetylene H–C≡C–H, the bond order between the two carbon atoms is also 3, and the C–H bond order is 1 (single bond). In carbon monoxide, , the bond order between carbon and oxygen is 3. In thiazyl trifluoride , the bond order between sulfur and nitrogen is 3, and between sulfur and fluorine is 1. In diatomic oxygen O=O the bond order is 2 (double bond). In ethylene the bond order between the two carbon atoms is also 2. The bond order between carbon and oxygen in carbon dioxide O=C=O is also 2. In phosgene , the bond order between carbon and oxygen is 2, and between carbon and chlorine is 1.
In some molecules, bond orders can be 4 (quadruple bond), 5 (quintuple bond) or even 6 (sextuple bond). For example, potassium octachlorodimolybdate salt () contains the anion, in which the two Mo atoms are linked to each other by a bond with order of 4. Each Mo atom is linked to four ligands by a bond with order o
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https://en.wikipedia.org/wiki/Jon%20Kleinberg
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Jon Michael Kleinberg (born 1971) is an American computer scientist and the Tisch University Professor of Computer Science and Information Science at Cornell University known for his work in algorithms and networks. He is a recipient of the Nevanlinna Prize by the International Mathematical Union.
Early life and education
Jon Kleinberg was born in 1971 in Boston, Massachusetts to a mathematics professor father and a computer consultant mother. He received a Bachelor of Science degree in computer science from Cornell University in 1993 and a PhD from Massachusetts Institute of Technology in 1996. He is the older brother of fellow Cornell computer scientist Robert Kleinberg.
Career
Since 1996 Kleinberg has been a professor in the Department of Computer Science at Cornell, as well as a visiting scientist at IBM's Almaden Research Center. His work has been supported by an NSF Career Award, an ONR Young Investigator Award, a MacArthur Foundation Fellowship, a Packard Foundation Fellowship, a Sloan Foundation Fellowship, and grants from Google, Yahoo!, and the NSF. He is a member of the National Academy of Engineering and the American Academy of Arts and Sciences. In 2011, he was elected to the United States National Academy of Sciences. In 2013 he became a fellow of the Association for Computing Machinery.
Research
Kleinberg is best known for his work on networks. One of his best-known contributions is the HITS algorithm, developed while he was at IBM. HITS is an algorithm for
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https://en.wikipedia.org/wiki/J%C3%B3zef%20H.%20Przytycki
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Józef Henryk Przytycki (, ; born 14 October 1953 in Warsaw, Poland), is a Polish mathematician specializing in the fields of knot theory and topology.
Academic background
Przytycki received a Master of Science degree in mathematics from University of Warsaw in 1977 and a PhD in mathematics from Columbia University (1981) advised by Joan Birman. Przytycki then returned to Poland, where he became an assistant professor at the University of Warsaw. From 1986 to 1995 he held visiting positions at the University of British Columbia, the University of Toronto, Michigan State University, the Institute for Advanced Study in Princeton, New Jersey, the University of California, Riverside, Odense University, and the University of California, Berkeley.
In 1995 he joined the Mathematics Department at George Washington University in Washington, D.C., where he became a professor in 1999. According to the Mathematics Genealogy Project, he has supervised 16 PhD students (as of 2022).
Research
Przytycki co-authored more than 100 research papers, 25 conference proceedings and 2 books.
In 1987, Przytycki and Pawel Traczyk published a paper that included a description of what is now called the HOMFLY(PT) polynomial. Postal delays prevented Przytycki and Traczyk from receiving full recognition alongside the other six discoverers. Przytycki also introduced skein modules in a paper published in 1991; see also his entry in the online Encyclopedia of Mathematics.
Przytycki has co-organized t
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https://en.wikipedia.org/wiki/Heim%20theory
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Heim theory, first proposed by German physicist Burkhard Heim publicly in 1957, is an attempt to develop a theory of everything in theoretical physics. The theory claims to bridge some of the disagreements between quantum mechanics and general relativity. The theory has received little attention in the scientific literature and is regarded as being outside mainstream science but has attracted some interest in popular and fringe media.
Development
Heim attempted to resolve incompatibilities between quantum theory and general relativity. To meet that goal, he developed a mathematical approach based on quantizing spacetime. Others have attempted to apply Heim theory to nonconventional space propulsion and faster than light concepts, as well as the origin of dark matter.
Heim claimed that his theory yields particle masses directly from fundamental physical constants and that the resulting masses are in agreement with experiment, but this claim has not been confirmed. Heim's theory is formulated mathematically in six or more dimensions and uses Heim's own version of difference equations.
References
External links
Chronological Overview of the Research of Burkhard Heim (5 pages, English translation by John Reed, Feb 2011)
Heim Theory Falsified. Next Big Future. 1 July 2011. This article posts John Reed's comments.
General Discussions. Heim Theory. The Physics Forum. 2013-03-26.
Heim Theory Translation. Borje Mansson and Anton Mueller. 2006.
Discussion about Burkhard Heim'
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https://en.wikipedia.org/wiki/Armagh%20Observatory
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Armagh Observatory is an astronomical research institute in Armagh, Northern Ireland. Around 25 astronomers are based at the observatory, studying stellar astrophysics, the Sun, Solar System astronomy and Earth's climate.
In 2018, Armagh Observatory was recognized for having 224 years of unbroken weather records.
History
The Observatory is located close to the centre of the city of Armagh, adjacent to the Armagh Planetarium in approximately of landscaped grounds known as the Armagh Astropark. It was founded in 1789 by The Most Rev. and Rt Hon. The 1st Baron Rokeby, Church of Ireland Lord Primate of All Ireland and Lord Archbishop of Armagh.
In 1795 through 1797 Solar observations were made at Armagh, including measurements of sunspots.
Ernst Julius Öpik (grandfather of Lembit Öpik MP) was based here for over 30 years and among his many contributions to astrophysics he wrote of the dangers of an asteroid impacting on the Earth.
One of the observatory's directors, Thomas Romney Robinson invented the cup anemometer, a device for measuring wind speed.
A plan was announced in 1949 to establish an Armagh Planetarium. After many years work the Planetarium opened in 1968, its first director was Patrick Moore. It celebrated its 50th anniversary in 2018.
In 2018, the observatory was given an award by Centennial Weather Station Award from the World Meteorological Organisation for 224 years of unbroken weather recordings. The records go back to 1794 and are also made available o
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https://en.wikipedia.org/wiki/Hilbert%27s%20syzygy%20theorem
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In mathematics, Hilbert's syzygy theorem is one of the three fundamental theorems about polynomial rings over fields, first proved by David Hilbert in 1890, which were introduced for solving important open questions in invariant theory, and are at the basis of modern algebraic geometry. The two other theorems are Hilbert's basis theorem that asserts that all ideals of polynomial rings over a field are finitely generated, and Hilbert's Nullstellensatz, which establishes a bijective correspondence between affine algebraic varieties and prime ideals of polynomial rings.
Hilbert's syzygy theorem concerns the relations, or syzygies in Hilbert's terminology, between the generators of an ideal, or, more generally, a module. As the relations form a module, one may consider the relations between the relations; the theorem asserts that, if one continues in this way, starting with a module over a polynomial ring in indeterminates over a field, one eventually finds a zero module of relations, after at most steps.
Hilbert's syzygy theorem is now considered to be an early result of homological algebra. It is the starting point of the use of homological methods in commutative algebra and algebraic geometry.
History
The syzygy theorem first appeared in Hilbert's seminal paper "Über die Theorie der algebraischen Formen" (1890). The paper is split into five parts: part I proves Hilbert's basis theorem over a field, while part II proves it over the integers. Part III contains the syzygy t
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https://en.wikipedia.org/wiki/Fluid%20Science%20Laboratory
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The Fluid Science Laboratory is a European (ESA's) science payload designed for use in Columbus built by Alenia Spazio, OHB-System and Verhaert Design and Development. It is a multi-user facility for conducting fluid physics research in microgravity conditions. It can be operated in fully or in semi-automatic mode and can be controlled on board by the ISS astronauts, or from the ground in the so-called telescience mode.
The major objective of performing fluid science experiments in space is to study dynamic phenomena in the absence of gravitational forces. Under microgravity such forces are almost entirely eliminated thereby significantly reducing gravity-driven convection, sedimentation and stratification and fluid static pressure, allowing the study of fluid dynamic effects normally masked by gravity. These effects include diffusion-controlled heat and mass transfer.
The absence of gravity-driven convection eliminates the negative effects of density gradients (inhomogeneous mass distribution) that arise in processes involving heat treatment, phase transitions, diffusive transport or chemical reaction. Convection in terrestrial processes is a strong perturbing factor, the effects of which are seldom predictable with great accuracy and which dominate heat and mass transfer in fluids.
The ability to accurately control such processes remains limited, and their full understanding requires further fundamental research by conducting well-defined model experiments for developin
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https://en.wikipedia.org/wiki/Kryha
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In the history of cryptography, the Kryha machine was a device for encryption and decryption, appearing in the early 1920s and used until the 1950s. The machine was the invention of (born 31.10.1891 in Charkow, Russian Empire, committed suicide in Baden-Baden in 1955). During the Second World War, Kryha worked as an officer for the German Wehrmacht. There were several versions; the standard Kryha machine weighed around five kilograms, and was totally mechanical. A scaled down pocket version was introduced later on, termed the "Lilliput" model. There was also a more bulky electrical version.
The machine was used for a time by the German Diplomatic Corps, and was adopted by Marconi in England.
Operation
The machine consisted of two concentric rings each containing an alphabet. The inner alphabet was stepped a variable number of places by pushing a lever. In operation, the user would encrypt by finding the plaintext letter on one ring (usually the outer ring), and reading the corresponding letter on the other ring; this was then used as the ciphertext letter. When the lever was pressed, the inner ring would step, causing the relationship between the two alphabets to change. The stepping was irregular and governed by the use of a disk with a number of sectors, each containing a number of teeth.
Cryptanalysis
The security of the machine was evaluated by the mathematician Georg Hamel, who calculated the size of the key space. The US Army was also contacted to see if they woul
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https://en.wikipedia.org/wiki/Frederick%20Stark%20Pearson
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Fred Stark Pearson (July 3, 1861 – May 7, 1915) was an American electrical engineer and entrepreneur.
Biography
Pearson was the son of Ambrose and Hannah (Edgerly) Pearson. He graduated from Tufts University in 1883 with an A.M.B. and received an A.M.M. degree one year later. Previously, for one year (1879–80), he was instructor in chemistry in the Massachusetts Institute of Technology; later (1883–86), he was instructor in mathematics and applied mechanics at Tufts College. From college, he went on to develop the electric transportation system in Boston and, with electric powered streetcars of major importance, in 1894 he was appointed the head engineer for Metropolitan Street Railways in New York City. Pearson built a reputation as an innovative electrical engineer in the United States and he was soon contracted by governments and businesses as a consulting engineer for power generating stations throughout North America. A man with great business skills and a foresight, with ready financial backers he undertook major projects in North and South America. He was the Founder of Barcelona Traction and São Paulo Tramway, Light and Power Company which is now Brookfield Asset Management.
While in Canada, he developed a relationship with a bright and aggressive young lawyer/stockbroker in Montreal, Quebec by the name of James Dunn. Pearson encouraged Dunn to take up residency in London, at the time the most important financial market in the world.
With Dunn's brokerage house un
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https://en.wikipedia.org/wiki/Jane%20Margaret%20O%27Brien
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Jane Margaret O'Brien is a professor of chemistry and president emerita of St. Mary's College of Maryland. She served as president from 1996 to 2009. "Maggie", as she was called by students at St.
Mary's, received her BS in biochemistry at Vassar College in 1975, and her PhD in chemistry at the University of Delaware in 1981.
External links
Profile of Jane Margaret O'Brien
St. Mary's College of Maryland
Vassar College alumni
University of Delaware alumni
Year of birth missing (living people)
Living people
American women chemists
Women heads of universities and colleges
21st-century American women
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https://en.wikipedia.org/wiki/Condition
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Condition or conditions may refer to:
In philosophy and logic
Material conditional, a logical connective used to form "if...then..." statements
Necessary and sufficient condition, a statement which is true if and only if another given statement is true
In science and technology
In computer science
Exception handling#Condition systems, a generalization of exceptions in exception handling
Condition (SQL), a filtering mechanism in relational database queries
Condition variable, a synchronization primitive in concurrent programming
In medicine
Medical condition, as a synonym for disease
Medical state or condition, a patient's clinical status in a hospital
In numerical analysis
Condition number, a measure of a matrix in digital computation
In arts and entertainment
Condition (film), a 2011 film
Conditions (album), 2009 debut album by Australian rock band The Temper Trap
Conditions (magazine), an annual lesbian feminist literary magazine
Conditions (band), an American rock band
Just Dropped In (To See What Condition My Condition Was In), a song written by Mickey Newbury and first released in 1967
Status effect, a temporary condition of a character in computer gaming
Other uses
Conditions (Russia), part of the constitution of Russia, signed by Anna of Russia in 1730
In contract law, part of covenants, conditions and restrictions
Living condition
State of being
See also
Conditional (disambiguation)
Conditioner (disambiguation)
Conditioning (disambigua
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https://en.wikipedia.org/wiki/Terpyridine
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Terpyridine (2,2';6',2"-terpyridine, often abbreviated to Terpy or Tpy) is a heterocyclic compound derived from pyridine. It is a white solid that is soluble in most organic solvents. The compound is mainly used as a ligand in coordination chemistry.
Synthesis
Terpyridine was first synthesized by G. Morgan and F. H. Burstall in 1932 by the oxidative coupling of pyridines. This method, however, proceeded in low yields. More efficient syntheses have since been described, mainly starting from 2-acetylpyridine. One method produces an enaminone by the reaction of 2-acetylpyridine with N,N-dimethylformamide dimethyl acetal. The base-catalyzed reaction of 2-acetylpyridine with carbon disulfide followed by alkylation with methyl iodide gives C5H4NCOCH=C(SMe)2. Condensation of this species with 2-acetylpyridine forms the related 1,5-diketone, which condenses with ammonium acetate to form a terpyridine. Treatment of this derivative with Raney nickel removes the thioether group.
Other methods have been developed for the synthesis of terpyridine and its substituted derivatives. Substituted terpyridines are also synthesized from palladium-catalyzed cross-coupling reactions. It can be prepared from bis-triazinyl pyridine.
Properties
Terpyridine is a tridentate ligand that binds metals at three meridional sites giving two adjacent 5-membered MN2C2 chelate rings. Terpyridine forms complexes with most transition metal ion as do other polypyridine compounds, such as 2,2'-bipyridine a
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https://en.wikipedia.org/wiki/G%C3%A1bor%20A.%20Somorjai
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Gabor A. Somorjai (born May 4, 1935) is a professor of chemistry at the University of California, Berkeley, and is a leading researcher in the field of surface chemistry and catalysis, especially the catalytic effects of metal surfaces on gas-phase reactions ("heterogeneous catalysis"). For his contributions to the field, Somorjai won the Wolf Prize in Chemistry in 1998, the Linus Pauling Award in 2000, the National Medal of Science in 2002, the Priestley Medal in 2008, the 2010 BBVA Foundation Frontiers of Knowledge Award in Basic Science and the NAS Award in Chemical Sciences in 2013. In April 2015, Somorjai was awarded the American Chemical Society's William H. Nichols Medal.
Early history
Somorjai was born in Budapest in 1935 to Jewish parents. He was saved from the Nazis when his mother sought the assistance of Raoul Wallenberg in 1944 who issued Swedish passports to Somorjai's mother, himself and his sister saving them from the Nazi death camps. While Somorjai's father ended up in the camp system, he was fortunate to survive but many of Somorjai's extended family ended up in the camp system.
He was studying chemical engineering at the Budapest University of Technology and Economics in 1956. As a participant in the 1956 Hungarian Revolution, Somorjai left Hungary to go to the US after the Soviet invasion. Along with other Hungarian immigrants, Somorjai enrolled in graduate study at Berkeley and obtained his doctorate in 1960. He joined IBM's research staff in Yorktown
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https://en.wikipedia.org/wiki/McClintocksville%2C%20Pennsylvania
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McClintockville, Pennsylvania was a small community in Cornplanter Township in Venango County located in the state of Pennsylvania in the United States.
History
Venango County, Pennsylvania was home to an oil boom in the years following discovery of natural oil (petroleum) in the mid-1850s.
George Bissell, a Yale University chemistry professor, and Edwin L. Drake, a former railroad conductor, made the first successful use of a drilling rig on August 28, 1859 at Titusville, Pennsylvania. This single well soon exceeded the entire cumulative oil output of Europe since the 1650s. The principal product of the oil was kerosene.
In 1861, McClintockville was the location of Wamsutta Oil Refinery, the first business venture of Henry Huttleston Rogers, who became a leading American businessman, industrialist and financier. Rogers and his young wife Abbie Palmer Gifford Rogers lived in a one-room shack there along Oil Creek for several years.
Shortly later, Rogers met oil pioneer Charles Pratt who purchased the entire output of the tiny Wamsutta Oil Refinery. In 1867, Rogers joined Pratt in forming Charles Pratt and Company, which was purchased by Standard Oil in 1874. Rogers became one of the key men in John D. Rockefeller’s Standard Oil Trust.
After joining Standard Oil, Rogers invested heavily in various industries, including copper, steel, mining, and railways. The Virginian Railway is widely considered his final life's achievement. Rogers amassed a great fortune, estimated a
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https://en.wikipedia.org/wiki/Hyperbolic%20metric%20space
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In mathematics, a hyperbolic metric space is a metric space satisfying certain metric relations (depending quantitatively on a nonnegative real number δ) between points. The definition, introduced by Mikhael Gromov, generalizes the metric properties of classical hyperbolic geometry and of trees. Hyperbolicity is a large-scale property, and is very useful to the study of certain infinite groups called Gromov-hyperbolic groups.
Definitions
In this paragraph we give various definitions of a -hyperbolic space. A metric space is said to be (Gromov-) hyperbolic if it is -hyperbolic for some .
Definition using the Gromov product
Let be a metric space. The Gromov product of two points with respect to a third one is defined by the formula:
Gromov's definition of a hyperbolic metric space is then as follows: is -hyperbolic if and only if all satisfy the four-point condition
Note that if this condition is satisfied for all and one fixed base point , then it is satisfied for all with a constant . Thus the hyperbolicity condition only needs to be verified for one fixed base point; for this reason, the subscript for the base point is often dropped from the Gromov product.
Definitions using triangles
Up to changing by a constant multiple, there is an equivalent geometric definition involving triangles when the metric space is geodesic, i.e. any two points are end points of a geodesic segment (an isometric image of a compact subinterval of the reals). Note that the d
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https://en.wikipedia.org/wiki/Yuhan%20University
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Yuhan University is a private college in Sosa-gu, Bucheon City, Gyeonggi Province, South Korea. The current president is Kwon-Hyun Lee. It offers technical training in a variety of fields. The college's academic offerings are divided under five general divisions: Mechanical Engineering Division, Electrical and Electronic Engineering Division, Design Division, Computer and Management Division, and Social Affairs Division.
History
Ground was broken for "Yuhan Technical Junior College" in late 1977, and classes began the following year. The first president was Chong Ryul Sohn. In 1979 it became Yuhan Technical College. In 1998 the current English name "Yuhan College" was adopted. The Korean name "Yuhan Daehakgyo" was adopted in 2011.
Founding Philosophy
The profit derived from a business enterprise should be returned to the society which nourished the growth of the business.
(The founder, Dr. Ilhan New (Yu Il-han) believed that education is one of the most important ways that fulfill the above philosophy.)
School Motto
Be a freeman who dedicates himself to the peace of mankind.
Notable alumni
Sung Dong-il, actor
See also
Ilhan New
Yuhan Corporation
Education in South Korea
List of universities and colleges in South Korea
External links
(in English)
Universities and colleges in Gyeonggi Province
1977 establishments in South Korea
Educational institutions established in 1977
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https://en.wikipedia.org/wiki/LHCb%20experiment
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The LHCb (Large Hadron Collider beauty) experiment is a particle physics detector experiment collecting data at the Large Hadron Collider at CERN. LHCb is a specialized b-physics experiment, designed primarily to measure the parameters of CP violation in the interactions of b-hadrons (heavy particles containing a bottom quark). Such studies can help to explain the matter-antimatter asymmetry of the Universe. The detector is also able to perform measurements of production cross sections, exotic hadron spectroscopy, charm physics and electroweak physics in the forward region. The LHCb collaboration, who built, operate and analyse data from the experiment, is composed of approximately 1260 people from 74 scientific institutes, representing 16 countries. Chris Parkes succeeded on July 1, 2020 as spokesperson for the collaboration from Giovanni Passaleva (spokesperson 2017-2020). The experiment is located at point 8 on the LHC tunnel close to Ferney-Voltaire, France just over the border from Geneva. The (small) MoEDAL experiment shares the same cavern.
Physics goals
The experiment has wide physics program covering many important aspects of heavy flavour (both beauty and charm), electroweak and quantum chromodynamics (QCD) physics. Six key measurements have been identified involving B mesons. These are described in a roadmap document that formed the core physics programme for the first high energy LHC running in 2010–2012. They include:
Measuring the branching ratio of the rare
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https://en.wikipedia.org/wiki/Geometry%20template
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A geometry template is a piece of clear plastic with cut-out shapes for use in mathematics and other subjects in primary school through secondary school. It also has various measurements on its sides to be used like a ruler. In Australia, popular brands include Mathomat and MathAid.
Brands
Mathomat and Mathaid
Mathomat is a trademark used for a plastic stencil developed in Australia by Craig Young in 1969, who originally worked as an engineering tradesperson in the Government Aircraft Factories (GAF) in Melbourne before retraining and working as head of mathematics in a secondary school in Melbourne. Young designed Mathomat to address what he perceived as limitations of traditional mathematics drawing sets in classrooms, mainly caused by students losing parts of the sets. The Mathomat stencil has a large number of geometric shapes stencils combined with the functions of a technical drawing set (rulers, set squares, protractor and circles stencils to replace a compass).
The template made use polycarbonate – a new type of thermoplastic polymer when Mathomat first came out – which was strong and transparent enough to allow for a large number of stencil shapes to be included in its design without breaking or tearing. The first template was exhibited in 1970 at a mathematics conference in Melbourne along with a series of popular mathematics teaching lesson plan; it became an immediate success with a large number of schools specifying it as a required students purchase. As of
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https://en.wikipedia.org/wiki/Harvard%20Science%20Center
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The Harvard University Science Center is Harvard's main classroom and laboratory building for undergraduate science and mathematics, in addition to housing numerous other facilities and services.
Located just north of Harvard Yard, the Science Center was built in 1972 and opened in 1973 after a design by Josep Lluís Sert (then dean of the Harvard Graduate School of Design).
History
Planning
Harvard had been interested in building an undergraduate science center in the 1950s and 1960s. However, in the midst of an economic decline, funding could not be found. No concrete plans were made until in 1968, Edwin Land, inventor of the Polaroid "Land" camera, made a $12.5 million donation to construct a science center specifically for undergraduates.
Opponents of the plan feared that insufficient monies would be found to complete the project, and that the building's maintenance costs would be unreasonably high. The Biology Department also protested the move of its undergraduate-instruction facilities far from the department's main quarters. Professor George Wald argued that this would degrade the quality of instruction. There was also dissatisfaction with cancellation of plans at that time for a new biochemistry building.
The plan called for demolition of Lawrence Hall, a laboratory and a living space built in 1848. By the time of the scheduled demolition, a commune of students and "street people" calling themselves the "Free University" had taken residence in the unused buildi
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https://en.wikipedia.org/wiki/Pretzel%20knot
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A Pretzel knot may refer to:
Pretzel link: a concept in mathematics
Soft pretzel with garlic
Stafford knot: a rope knot used in sailing and heraldry
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https://en.wikipedia.org/wiki/Satish%20Dhawan
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Satish Dhawan (25 September 1920 – 3 January 2002) was an Indian mathematician and aerospace engineer, widely regarded as the father of experimental fluid dynamics research in India. Born in Srinagar, Dhawan was educated in India and further on in United States. Dhawan was one of the most eminent researchers in the field of turbulence and boundary layers, leading the successful and indigenous development of the Indian space programme. He succeeded M. G. K. Menon, as the third chairman of the Indian Space Research Organisation (ISRO) in 1972.
Education
Dhawan was a graduate of what is now called Punjab Engineering College in the city of Chandigarh in India, the [Mughalpura Technical College] in Lahore, Pakistan, undivided India, where he completed a Bachelor of Science in physics and mathematics, a bachelor's degree in Mechanical Engineering and a Master of Arts in English literature. In 1947, he completed a Master of Science degree in aerospace engineering from the University of Minnesota, Minneapolis, and an aeronautical engineering degree from the California Institute of Technology followed by a double PhD in mathematics and aerospace engineering under the supervision of his advisor Hans W. Liepmann in 1951.
Leadership in space research
In 1972, Dhawan became chairman of the Indian Space Research Organisation (ISRO) and secretary to the Government of India at the Department of Space.
APJ Abdul Kalam explained that in 1979 when he was the director of a Satellite Launch
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https://en.wikipedia.org/wiki/Eino%20Kaila
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Eino Sakari Kaila (8 August 1890 – 31 July 1958) was a Finnish philosopher, critic and teacher. He worked in numerous fields including psychology (sometimes considered to be the founder of Finnish psychology), physics and theater, and attempted to find unifying principles behind various branches of human and natural sciences.
Life
Eino Kaila was born in Alajärvi, Finland. Kaila's father, Erkki Kaila, was a Protestant minister and later archbishop. He graduated from the University of Helsinki in 1910. In the 1920s he worked in the field of literary criticism and psychology as a professor at the University of Turku and is said to have been the first to introduce gestalt psychology to Finland. He was a part of the cultural circles of the time with the likes of Jean Sibelius and Frans Eemil Sillanpää. In 1916 he married the painter Anna Lovisa Snellman, who was granddaughter of Johan Vilhelm Snellman. He had University positions as lecturer in Helsinki and professor in Turku, and in 1930 he was appointed professor of theoretical philosophy at the University of Helsinki. In the 1930s, Kaila was closely associated with the Vienna Circle.
During World War II, Kaila lectured in Germany. In 1948 Kaila became a member of the Finnish Academy. He died in Kirkkonummi on 31 July 1958.
Ideas
Despite being greatly influenced by the logical positivists and critical of unempirical speculation, an aspect common to all of Kaila's work was in strive for a holistic, almost pantheistic unde
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https://en.wikipedia.org/wiki/Use-define%20chain
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Within computer science, a Use-Definition Chain (UD Chain) is a data structure that consists of a use, U, of a variable, and all the definitions, D, of that variable that can reach that use without any other intervening definitions. A UD Chain generally means the assignment of some value to a variable.
A counterpart of a UD Chain is a Definition-Use Chain (DU Chain), which consists of a definition, D, of a variable and all the uses, U, reachable from that definition without any other intervening definitions.
Both UD and DU chains are created by using a form of static code analysis known as data flow analysis. Knowing the use-def and def-use chains for a program or subprogram is a prerequisite for many compiler optimizations, including constant propagation and common subexpression elimination.
Purpose
Making the use-define or define-use chains is a step in liveness analysis, so that logical representations of all the variables can be identified and tracked through the code.
Consider the following snippet of code:
int x = 0; /* A */
x = x + y; /* B */
/* 1, some uses of x */
x = 35; /* C */
/* 2, some more uses of x */
Notice that x is assigned a value at three points (marked A, B, and C). However, at the point marked "1", the use-def chain for x should indicate that its current value must have come from line B (and its value at line B must have come from line A). Contrariwise, at the point marked "2", the use-def chain for x indicates that its current val
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https://en.wikipedia.org/wiki/Equine%20coat%20color%20genetics
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Equine coat color genetics determine a horse's coat color. Many colors are possible, but all variations are produced by changes in only a few genes. Bay is the most common color of horses. A change at the agouti locus is capable of turning bay to black, while a mutation at the extension locus can turn bay or black to chestnut.
Over these three "base" colors can be any number of dilution genes and patterning genes. The dilution genes include the wildtype dun gene, believed to be one of the oldest colors extant in horses and donkeys. Depending on whether it acts on a bay, black, or chestnut base coat, it produces the colors known as bay dun, grullo, and red dun. Another common dilution gene is the cream gene, responsible for palomino, buckskin, and cremello horses. Less common dilutions include Pearl, champagne and silver dapple. Some of these genes also lighten eye color. Genes that affect the distribution of melanocytes create patterns of white spotting or speckling such as in roan, pinto, leopard, white or white spotting, and even some white markings. Finally, the gray gene causes depigmentation of the hair shaft, slowly adding white hairs over the course of several years until the horse's body hair is near or completely white.
Some of these patterns have complex interactions. For example, a single horse may carry both dilution and white patterning genes, or carry genes for more than one spotting pattern. Horses with a gray gene can be born any color and their hair
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https://en.wikipedia.org/wiki/Vertex%20operator%20algebra
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In mathematics, a vertex operator algebra (VOA) is an algebraic structure that plays an important role in two-dimensional conformal field theory and string theory. In addition to physical applications, vertex operator algebras have proven useful in purely mathematical contexts such as monstrous moonshine and the geometric Langlands correspondence.
The related notion of vertex algebra was introduced by Richard Borcherds in 1986, motivated by a construction of an infinite-dimensional Lie algebra due to Igor Frenkel. In the course of this construction, one employs a Fock space that admits an action of vertex operators attached to elements of a lattice. Borcherds formulated the notion of vertex algebra by axiomatizing the relations between the lattice vertex operators, producing an algebraic structure that allows one to construct new Lie algebras by following Frenkel's method.
The notion of vertex operator algebra was introduced as a modification of the notion of vertex algebra, by Frenkel, James Lepowsky, and Arne Meurman in 1988, as part of their project to construct the moonshine module. They observed that many vertex algebras that appear 'in nature' carry an action of the Virasoro algebra, and satisfy a bounded-below property with respect to an energy operator. Motivated by this observation, they added the Virasoro action and bounded-below property as axioms.
We now have post-hoc motivation for these notions from physics, together with several interpretations of the axio
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https://en.wikipedia.org/wiki/Proca%20action
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In physics, specifically field theory and particle physics, the Proca action describes a massive spin-1 field of mass m in Minkowski spacetime. The corresponding equation is a relativistic wave equation called the Proca equation. The Proca action and equation are named after Romanian physicist Alexandru Proca.
The Proca equation is involved in the Standard Model and describes there the three massive vector bosons, i.e. the Z and W bosons.
This article uses the (+−−−) metric signature and tensor index notation in the language of 4-vectors.
Lagrangian density
The field involved is a complex 4-potential , where is a kind of generalized electric potential and is a generalized magnetic potential. The field transforms like a complex four-vector.
The Lagrangian density is given by:
where is the speed of light in vacuum, is the reduced Planck constant, and is the 4-gradient.
Equation
The Euler–Lagrange equation of motion for this case, also called the Proca equation, is:
which is equivalent to the conjunction of
with (in the massive case)
which may be called a generalized Lorenz gauge condition. For non-zero sources, with all fundamental constants included, the field equation is:
When , the source free equations reduce to Maxwell's equations without charge or current, and the above reduces to Maxwell's charge equation. This Proca field equation is closely related to the Klein–Gordon equation, because it is second order in space and time.
In the vector calculus not
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https://en.wikipedia.org/wiki/Civil
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Civil may refer to:
Civic virtue, or civility
Civil action, or lawsuit
Civil affairs
Civil and political rights
Civil disobedience
Civil engineering
Civil (journalism), a platform for independent journalism
Civilian, someone not a member of armed forces
Civil law (disambiguation), multiple meanings
Civil liberties
Civil religion
Civil service
Civil society
Civil war
Civil (surname)
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https://en.wikipedia.org/wiki/Matt%20Blaze
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Matt Blaze is an American researcher who focuses on the areas of secure systems, cryptography, and trust management. He is currently the McDevitt Chair of Computer Science and Law at Georgetown University, and is on the board of directors of the Tor Project.
Work
Blaze received his PhD in computer science from Princeton University.
In 1992, while working for AT&T, Blaze implemented a strong cryptographic package known as "CFS", the Cryptographic File System, for Unix, since ported to Linux. CFS uses Network File System as its transport mechanism, allowing users to encrypt selected directory hierarchies, but mount them unencrypted after providing the key. In November, 1993, he presented a paper on this project, "A Cryptographic File System for Unix", at the 1st ACM Conference on Computer and Communications Security. Blaze also published a paper "Key Management in an Encrypting File System", in the Proceedings USENIX Summer 1994 Technical Conference.
In the early 1990s, at the height of the "crypto war", Blaze was a participant in the Cypherpunks mailing list and in 1994, he found a critical weakness in the wiretapping mechanisms of the Clipper chip.
His paper, Protocol Failure in the Escrowed Encryption Standard, pointed out that the Clipper's escrow system had a serious vulnerability: a brute-force attack could allow the Clipper chip to be used as an encryption device, while disabling the key escrow capability. Later during this time, he was one of the authors of a semina
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https://en.wikipedia.org/wiki/Archimedean
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Archimedean means of or pertaining to or named in honor of the Greek mathematician Archimedes and may refer to:
Mathematics
Archimedean absolute value
Archimedean circle
Archimedean constant
Archimedean copula
Archimedean field
Archimedean group
Archimedean point
Archimedean property
Archimedean solid
Archimedean spiral
Archimedean tiling
Other uses
Archimedean screw
Claw of Archimedes
The Archimedeans, the mathematical society of the University of Cambridge
Archimedean Dynasty
Archimedean Upper Conservatory
See also
Archimedes (disambiguation)
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https://en.wikipedia.org/wiki/Washburn%27s%20equation
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In physics, Washburn's equation describes capillary flow in a bundle of parallel cylindrical tubes; it is extended with some issues also to imbibition into porous materials. The equation is named after Edward Wight Washburn; also known as Lucas–Washburn equation, considering that Richard Lucas wrote a similar paper three years earlier, or the Bell-Cameron-Lucas-Washburn equation, considering J.M. Bell and F.K. Cameron's discovery of the form of the equation in 1906.
Derivation
In its most general form the Lucas Washburn equation describes the penetration length () of a liquid into a capillary pore or tube with time as , where is a simplified diffusion coefficient. This relationship, which holds true for a variety of situations, captures the essence of Lucas and Washburn's equation and shows that capillary penetration and fluid transport through porous structures exhibit diffusive behaviour akin to that which occurs in numerous physical and chemical systems. The diffusion coefficient is governed by the geometry of the capillary as well as the properties of the penetrating fluid.
A liquid having a dynamic viscosity and surface tension will penetrate a distance into the capillary whose pore radius is following the relationship:
Where is the contact angle between the penetrating liquid and the solid (tube wall).
Washburn's equation is also used commonly to determine the contact angle of a liquid to a powder using a force tensiometer.
In the case of porous materials
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https://en.wikipedia.org/wiki/Next-bit%20test
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In cryptography and the theory of computation, the next-bit test is a test against pseudo-random number generators. We say that a sequence of bits passes the next bit test for at any position in the sequence, if any attacker who knows the first bits (but not the seed) cannot predict the st with reasonable computational power.
Precise statement(s)
Let be a polynomial, and be a collection of sets such that contains -bit long sequences. Moreover, let be the probability distribution of the strings in .
We now define the next-bit test in two different ways.
Boolean circuit formulation
A predicting collection is a collection of boolean circuits, such that each circuit has less than gates and exactly inputs. Let be the probability that, on input the first bits of , a string randomly selected in with probability , the circuit correctly predicts , i.e. :
Now, we say that passes the next-bit test if for any predicting collection , any polynomial :
Probabilistic Turing machines
We can also define the next-bit test in terms of probabilistic Turing machines, although this definition is somewhat stronger (see Adleman's theorem). Let be a probabilistic Turing machine, working in polynomial time. Let be the probability that predicts the st bit correctly, i.e.
We say that collection passes the next-bit test if for all polynomial , for all but finitely many , for all :
Completeness for Yao's test
The next-bit test is a particular case of Yao's test for random se
|
https://en.wikipedia.org/wiki/Reactive
|
Reactive may refer to:
Generally, capable of having a reaction (disambiguation)
An adjective abbreviation denoting a bowling ball coverstock made of reactive resin
Reactivity (chemistry)
Reactive mind
Reactive programming
See also
Reactance (disambiguation)
Reactivity (disambiguation)
|
https://en.wikipedia.org/wiki/Digestive
|
Digestive may refer to:
Biology
Digestion, biological process of metabolism
Food and drink
Digestif, small beverage at the end of a meal
Digestive biscuit, a British semi-sweet biscuit
|
https://en.wikipedia.org/wiki/Giovanni%20Battista%20Amici
|
Giovanni Battista Amici (; 25 March 1786 – 10 April 1863) was an Italian astronomer, microscopist, and botanist.
Amici was born in Modena, in present-day Italy. After studying at Bologna, he became professor of mathematics at Modena, and in 1831 was appointed inspector-general of studies in the Duchy of Modena. A few years later he was chosen director of the observatory at Florence, where he also lectured at the museum of natural history. Amici died in Florence in 1863.
His name is best known for the improvements he effected in the mirrors of reflecting telescopes and especially in the construction of the microscope. He was also a diligent and skillful observer, and busied himself not only with astronomical subjects, such as the double stars, the satellites of Jupiter and the measurement of the polar and equatorial diameters of the sun, but also with biological studies of the circulation of the sap in plants, the fructification of plants, infusoria etc. He was the first to observe the pollen tube.
He invented the dipleidoscope and also the direct vision prism.
The crater Amici on the Moon is named in his honour.
See also
Amici prism
Amici roof prism
Petrographic microscope
References
Further reading
(Note: this source gives Amici's date of death as 1868).
External links
Some places and memories related to Giovanni Battista Amici
Giovanni Battista Amici: Optical Instrument Maker, Astronomer. Naturalist
19th-century Italian astronomers
Microscopists
19th-century I
|
https://en.wikipedia.org/wiki/Tries
|
Tries may refer to the plural form of:
Try (rugby)
Try, a conversion (gridiron football)
Trie, a prefix tree in computer science
|
https://en.wikipedia.org/wiki/2%E2%80%933%E2%80%934%20tree
|
In computer science, a 2–3–4 tree (also called a 2–4 tree) is a self-balancing data structure that can be used to implement dictionaries. The numbers mean a tree where every node with children (internal node) has either two, three, or four child nodes:
a 2-node has one data element, and if internal has two child nodes;
a 3-node has two data elements, and if internal has three child nodes;
a 4-node has three data elements, and if internal has four child nodes;
2–3–4 trees are B-trees of order 4; like B-trees in general, they can search, insert and delete in O(log n) time. One property of a 2–3–4 tree is that all external nodes are at the same depth.
2–3–4 trees are isomorphic to red–black trees, meaning that they are equivalent data structures. In other words, for every 2–3–4 tree, there exists at least one and at most one red–black tree with data elements in the same order. Moreover, insertion and deletion operations on 2–3–4 trees that cause node expansions, splits and merges are equivalent to the color-flipping and rotations in red–black trees. Introductions to red–black trees usually introduce 2–3–4 trees first, because they are conceptually simpler. 2–3–4 trees, however, can be difficult to implement in most programming languages because of the large number of special cases involved in operations on the tree. Red–black trees are simpler to implement, so tend to be used instead.
Properties
Every node (leaf or internal) is a 2-node, 3-node or a 4-node, and holds
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https://en.wikipedia.org/wiki/HOM
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HOM, Hom or similar may refer to:
Places
Le Hom, former name of the commune Thury-Harcourt-le-Hom in France
Hom, Šentrupert, a dispersed settlement in Slovenia
Hom-e Khosrow, a village in Iran
Science and mathematics
Hom bundle, in topology
Hom functor, in category theory
, the set of linear forms from a vector space to its field
Higher-order modulation, in telecommunications
Hong–Ou–Mandel effect in quantum optics
Other uses
Hom (surname), a Danish, Dutch, English, and Taishanese surname
Hom (instrument), a class of traditional Mayan musical instruments
H0m scale, a model railway scale or gauge
Hall of mirrors effect, in computer graphics
Harm to ongoing matter, phrase used for class of material being redacted from the Mueller Report, for reasons of legal investigation
Head of mission, the head of a diplomatic representation
Heart of Midlothian F.C., an association football club in Scotland
Heart of Misery, a song by Finnish rock band The Rasmus
Ho Man Tin station, Hong Kong, MTR station code
Holland (Amtrak station), in Michigan, United States
Homa language, spoken in South Sudan
Homa (ritual), in Hinduism
Homer Airport in Homer, Alaska
House of Milan, an American publisher of bondage magazines
Armenian Relief Society (Armenian: , HOM)
His Orthodox Majesty, a title occasionally used by kings in Poland
HOM, a luxury men's underwear brand owned by Triumph International
See also
Homs (disambiguation)
|
https://en.wikipedia.org/wiki/Saturable%20reactor
|
A saturable reactor in electrical engineering is a special form of inductor where the magnetic core can be deliberately saturated by a direct electric current in a control winding. Once saturated, the inductance of the saturable reactor drops dramatically. This decreases inductive reactance and allows increased flow of the alternating current (AC).
Design considerations
Saturable reactors provide a very simple means to remotely and proportionally control the AC through a load such as an incandescent lamp; the AC current is roughly proportional to the direct current (DC) through the control winding.
The power windings, the control winding, and the core are arranged so that the control winding is well isolated from the AC power. The AC power windings are also usually configured so that they self-cancel any AC voltage that might otherwise be induced in the control winding.
Because the required inductance to achieve dimming varies with the size of the load, saturable reactors often have multiple taps, allowing a small inductance to be used with a large load or a larger inductance to be used with a smaller load. In this way, the required magnitude of the control current can be kept roughly constant, no matter what the load.
Obsolete technology
Saturable reactors designed for mains (power-line) frequency are larger, heavier, and more expensive than electronic power controllers developed after the introduction of semiconductor electronic components, and have largely been replace
|
https://en.wikipedia.org/wiki/Ionosonde%20Juliusruh
|
The Ionosonde Juliusruh is a facility of the institute for atmospheric physics near Juliusruh in northeastern Germany for sounding the ionosphere with radar systems in the short wave range (frequencies between 1 MHz and 30 MHz). The landmark of the station is a 70 metre high grounded free standing steel framework tower, which was built in 1960/61 and which carries a cage aerial for the transmitter of the ionosonde.
See also
List of towers
External links
http://www.ionosonde.iap-kborn.de/indexeng.htm
http://www.skyscraperpage.com/diagrams/?b45849
Research institutes in Germany
Towers
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https://en.wikipedia.org/wiki/Linear%20phase
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In signal processing, linear phase is a property of a filter where the phase response of the filter is a linear function of frequency. The result is that all frequency components of the input signal are shifted in time (usually delayed) by the same constant amount (the slope of the linear function), which is referred to as the group delay. Consequently, there is no phase distortion due to the time delay of frequencies relative to one another.
For discrete-time signals, perfect linear phase is easily achieved with a finite impulse response (FIR) filter by having coefficients which are symmetric or anti-symmetric. Approximations can be achieved with infinite impulse response (IIR) designs, which are more computationally efficient. Several techniques are:
a Bessel transfer function which has a maximally flat group delay approximation function
a phase equalizer
Definition
A filter is called a linear phase filter if the phase component of the frequency response is a linear function of frequency. For a continuous-time application, the frequency response of the filter is the Fourier transform of the filter's impulse response, and a linear phase version has the form:
where:
A(ω) is a real-valued function.
is the group delay.
For a discrete-time application, the discrete-time Fourier transform of the linear phase impulse response has the form:
where:
A(ω) is a real-valued function with 2π periodicity.
k is an integer, and k/2 is the group delay in units of samples.
is a Fo
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https://en.wikipedia.org/wiki/Walsh%20matrix
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In mathematics, a Walsh matrix is a specific square matrix of dimensions 2, where n is some particular natural number. The entries of the matrix are either +1 or −1 and its rows as well as columns are orthogonal, i.e. dot product is zero. The Walsh matrix was proposed by Joseph L. Walsh in 1923. Each row of a Walsh matrix corresponds to a Walsh function.
The Walsh matrices are a special case of Hadamard matrices. The naturally ordered Hadamard matrix is defined by the recursive formula below, and the sequency-ordered Hadamard matrix is formed by rearranging the rows so that the number of sign changes in a row is in increasing order. Confusingly, different sources refer to either matrix as the Walsh matrix.
The Walsh matrix (and Walsh functions) are used in computing the Walsh transform and have applications in the efficient implementation of certain signal processing operations.
Formula
The Hadamard matrices of dimension 2k for k ∈ N are given by the recursive formula (the lowest order of Hadamard matrix is 2):
and in general
for 2 ≤ k ∈ N, where ⊗ denotes the Kronecker product.
Permutation
Rearrange the rows of the matrix according to the number of sign change of each row. For example, in
the successive rows have 0, 3, 1, and 2 sign changes. If we rearrange the rows in sequency ordering:
then the successive rows have 0, 1, 2, and 3 sign changes.
Alternative forms of the Walsh matrix
Sequency ordering
The sequency ordering of the rows of the Walsh matrix can be d
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https://en.wikipedia.org/wiki/Classical%20field%20theory
|
A classical field theory is a physical theory that predicts how one or more physical fields interact with matter through field equations, without considering effects of quantization; theories that incorporate quantum mechanics are called quantum field theories. In most contexts, 'classical field theory' is specifically intended to describe electromagnetism and gravitation, two of the fundamental forces of nature.
A physical field can be thought of as the assignment of a physical quantity at each point of space and time. For example, in a weather forecast, the wind velocity during a day over a country is described by assigning a vector to each point in space. Each vector represents the direction of the movement of air at that point, so the set of all wind vectors in an area at a given point in time constitutes a vector field. As the day progresses, the directions in which the vectors point change as the directions of the wind change.
The first field theories, Newtonian gravitation and Maxwell's equations of electromagnetic fields were developed in classical physics before the advent of relativity theory in 1905, and had to be revised to be consistent with that theory. Consequently, classical field theories are usually categorized as non-relativistic and relativistic. Modern field theories are usually expressed using the mathematics of tensor calculus. A more recent alternative mathematical formalism describes classical fields as sections of mathematical objects called fiber
|
https://en.wikipedia.org/wiki/Jonathan%20ben%20Joseph
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Jonathan ben Joseph was a Lithuanian rabbi and astronomer who lived in Risenoi, Grodno in the late 17th century and early 18th century. Jonathan studied astronomy and mathematics.
In 1710 Jonathan and his family lived a year in the fields due to a plague at Risenoi. He vowed that, on surviving, he would spread astronomical knowledge among his fellow believers. After he became blind, he went to Germany, where the bibliographer Wolf met him in 1725. Jonathan authored two astronomical commentaries: the Yeshu'ah be-Yisrael, on Maimonides' neomenia laws (Frankfort-on-the-Main, 1720); and Bi'ur, on Abraham ben Ḥiyya's Ẓurat ha-Areẓ (Offenbach, 1720).
References
17th-century astronomers
18th-century Polish–Lithuanian astronomers
Lithuanian astronomers
17th-century births
18th-century deaths
18th-century Lithuanian rabbis
17th-century Lithuanian rabbis
People from Grodno
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https://en.wikipedia.org/wiki/Thermal%20de%20Broglie%20wavelength
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In physics, the thermal de Broglie wavelength (, sometimes also denoted by ) is roughly the average de Broglie wavelength of particles in an ideal gas at the specified temperature. We can take the average interparticle spacing in the gas to be approximately where is the volume and is the number of particles. When the thermal de Broglie wavelength is much smaller than the interparticle distance, the gas can be considered to be a classical or Maxwell–Boltzmann gas. On the other hand, when the thermal de Broglie wavelength is on the order of or larger than the interparticle distance, quantum effects will dominate and the gas must be treated as a Fermi gas or a Bose gas, depending on the nature of the gas particles. The critical temperature is the transition point between these two regimes, and at this critical temperature, the thermal wavelength will be approximately equal to the interparticle distance. That is, the quantum nature of the gas will be evident for
i.e., when the interparticle distance is less than the thermal de Broglie wavelength; in this case the gas will obey Bose–Einstein statistics or Fermi–Dirac statistics, whichever is appropriate. This is for example the case for electrons in a typical metal at T = 300 K, where the electron gas obeys Fermi–Dirac statistics, or in a Bose–Einstein condensate. On the other hand, for
i.e., when the interparticle distance is much larger than the thermal de Broglie wavelength, the gas will obey Maxwell–Boltzmann statistics.
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https://en.wikipedia.org/wiki/Property%20P%20conjecture
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In mathematics, the Property P conjecture is a statement about 3-manifolds obtained by Dehn surgery on a knot in the 3-sphere. A knot in the 3-sphere is said to have Property P if every 3-manifold obtained by performing (non-trivial) Dehn surgery on the knot is not simply-connected. The conjecture states that all knots, except the unknot, have Property P.
Research on Property P was started by R. H. Bing, who popularized the name and conjecture.
This conjecture can be thought of as a first step to resolving the Poincaré conjecture, since the Lickorish–Wallace theorem says any closed, orientable 3-manifold results from Dehn surgery on a link.
If a knot has Property P, then one cannot construct a counterexample to the Poincaré conjecture by surgery along .
A proof was announced in 2004, as the combined result of efforts of mathematicians working in several different fields.
Algebraic Formulation
Let denote elements corresponding to a preferred longitude and meridian of a tubular neighborhood of .
has Property P if and only if its Knot group is never trivialised by adjoining a relation of the form for some .
See also
Property R conjecture
References
3-manifolds
Conjectures that have been proved
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https://en.wikipedia.org/wiki/RoboNexus
|
RoboNexus was a robotics event in the United States held from 2004 to 2005. Over 10,000 attended RoboNexus in 2004.
RoboNexus showcased advances in robotics for both industry representatives and the general public. Notable exhibitors included the company iRobot, creators of Roomba, and NASA.
Robotics Trends also produces an annual RoboBusiness conference.
Events
2005 - San Jose Convention Center, San Jose, California
External links
Robotics events
Robotics in the United States
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https://en.wikipedia.org/wiki/Non-Archimedean
|
In mathematics and physics, non-Archimedean refers to something without the Archimedean property. This includes:
Ultrametric space
notably, p-adic numbers
Non-Archimedean ordered field, namely:
Levi-Civita field
Hyperreal numbers
Surreal numbers
Dehn planes
Non-Archimedean time in theoretical physics
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https://en.wikipedia.org/wiki/Free%20particle
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In physics, a free particle is a particle that, in some sense, is not bound by an external force, or equivalently not in a region where its potential energy varies. In classical physics, this means the particle is present in a "field-free" space. In quantum mechanics, it means the particle is in a region of uniform potential, usually set to zero in the region of interest since the potential can be arbitrarily set to zero at any point in space.
Classical free particle
The classical free particle is characterized by a fixed velocity v. The momentum is given by
and the kinetic energy (equal to total energy) by
where m is the mass of the particle and v is the vector velocity of the particle.
Quantum free particle
Mathematical description
A free particle with mass in non-relativistic quantum mechanics is described by the free Schrödinger equation:
where ψ is the wavefunction of the particle at position r and time t. The solution for a particle with momentum p or wave vector k, at angular frequency ω or energy E, is given by a complex plane wave:
with amplitude A and has two different rules according to its mass:
if the particle has mass : (or equivalent ).
if the particle is a massless particle: .
The eigenvalue spectrum is infinitely degenerate since for each eigenvalue E>0, there corresponds an infinite number of eigenfunctions corresponding to different directions of .
The De Broglie relations: , apply. Since the potential energy is (stated to be) zero, the t
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https://en.wikipedia.org/wiki/Jakob%20Segal
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Jakob Segal (17 April 1911 – 30 September 1995) was a Russian-born German biology professor at Humboldt University of Berlin in the former East Germany. He was one of the advocates of the conspiracy theory that HIV was created by the United States government at Fort Detrick, Maryland.
After the fall of the Soviet Union, KGB defector Vasili Mitrokhin and two former members of East Germany's secret police accused Segal of being a Soviet disinformation agent who worked for the KGB.
Early life and education
Segal was born in Saint Petersburg, Russian Empire, into a Lithuanian Jewish family, the son of Hermann Segal, a merchant from Kaunas (1880–1941), and Rebekka (née Schlimakowski; 1887–1941). He had an older brother, Moshe, an electrician. When he was 8, his family moved to Königsberg, Prussia (now Kaliningrad, Russia). He was educated in Berlin and Munich, where he joined the Red Students' League (Roter Studentenbund) and the Communist Party of Germany. In 1933, he immigrated to France, where he furthered his studies in Toulouse before earning a doctorate in physiology from the Sorbonne in 1936.
During the Second World War, he and his German wife, Lilli (née Schlesinger, whom he had met at university in Toulouse) joined the resistance as part of the Main-d'œuvre immigrée and went underground. All of his family, including his parents and brother, were killed in the Holocaust. Lilli was arrested in 1943 and deported to Auschwitz in July 1944, but was sent to a work camp and
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https://en.wikipedia.org/wiki/Catholic%20University%20of%20Pusan
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The Catholic University of Pusan is situated in the southeastern South Korean port city of Busan. The current president is Son Sam-seok. The university is traditionally focused on nursing and health sciences, but in addition to these fields it includes schools of environmental science, business administration, computer information engineering, and social welfare. It enrolls about 1,200 students.
History
In 1964, the Maryknoll School of Nursing opened under the directorship of Rita Catherine Bonin, attached to Maryknoll Sisters Hospital. It was reorganized as Maryknoll Nursing Junior College in 1971. It was renamed Pusan Catholic College in 1990. In 1999, it united with Jisan College (est. 1979), another Catholic nursing school in Busan, to form the present-day entity of the Catholic University of Pusan.
An Organization of Education Topics
An ideology
Humanitarianism - Spirit of Catholicism/trust, love, service
Topic
An Honest volunteer (worker) for one person
Introduce of Department in Cup
We have 6 main departments and 17 majors in our school
College of Theology (신학대학)
College of Nursing (간호대학)
College of Health Sciences (보건과학대학)
College of Applied Sciences (응용과학대학)
College of Social Sciences (사회과학대학)
The Faculty of Management
The Faculty of Circulation Management Information
The Faculty of Social Welfare
College of Humanity Culture (인성교양부)
See also
List of colleges and universities in South Korea
Education in South Korea
External links
Official
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https://en.wikipedia.org/wiki/Jeffrey%20Weeks%20%28mathematician%29
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Jeffrey Renwick Weeks (born December 10, 1956) is an American mathematician, a geometric topologist and cosmologist. Weeks is a 1999 MacArthur Fellow.
Biography
Weeks received his BA from Dartmouth College in 1978, and his PhD in mathematics from Princeton University in 1985, under the supervision of William Thurston. Since then he has taught at Stockton State College, Ithaca College, and Middlebury College, but has spent much of his time as a free-lance mathematician.
Research
Weeks' research contributions have mainly been in the field of 3-manifolds and physical cosmology.
The Weeks manifold, discovered in 1985 by Weeks, is the hyperbolic 3-manifold with the minimum possible volume. Weeks has written various computer programs to assist in mathematical research and mathematical visualization. His SnapPea program is used to study hyperbolic 3-manifolds, while he has also developed interactive software to introduce these ideas to middle-school, high-school, and college students.
Weeks is particularly interested in using topology to understand the spatial universe. His book The Shape of Space: How to Visualize Surfaces and Three-dimensional Manifolds (Marcel Dekker, 1985, ) explores the geometry and topology of low-dimensional manifolds. The second edition (2002, ) explains some of his work in applying the material to cosmology.
Awards and honors
Weeks became a MacArthur Fellow in 1999. In 2007, he won the Levi L. Conant Prize for his expository paper, "The Poincaré Dode
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https://en.wikipedia.org/wiki/William%20Goldman%20%28mathematician%29
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William Mark Goldman (born 1955 in Kansas City, Missouri) is a professor of mathematics at the University of Maryland, College Park (since 1986). He received a B.A. in mathematics from Princeton University in 1977, and a Ph.D. in mathematics from the University of California, Berkeley in 1980.
Research contributions
Goldman has investigated geometric structures, in various incarnations, on manifolds since his undergraduate thesis, "Affine manifolds and projective geometry on manifolds", supervised by William Thurston and Dennis Sullivan. This work led to work with Morris Hirsch and David Fried on affine structures on manifolds, and work in real projective structures on compact surfaces. In particular he proved that the space of convex real projective structures on a closed orientable surface of genus is homeomorphic to an open cell of dimension . With Suhyoung Choi, he proved that this space is a connected component (the "Hitchin component") of the space of equivalence classes of representations of the fundamental group in . Combining this result with Suhyoung Choi's convex decomposition theorem, this led to a complete classification of convex real projective structures on compact surfaces.
His doctoral dissertation, "Discontinuous groups and the Euler class" (supervised by Morris W. Hirsch), characterizes discrete embeddings of surface groups in in terms of maximal Euler class, proving a converse to the Milnor–Wood inequality for flat bundles. Shortly thereafter he sh
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https://en.wikipedia.org/wiki/Topology%20%28disambiguation%29
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Topology is a branch of mathematics concerned with geometric properties preserved under continuous deformation (stretching without tearing or gluing).
Topology may also refer to:
Math
Topology, the collection of open sets used to define a topological space
Algebraic topology
Differential topology
Discrete topology
General topology
Geometric topology
Grothendieck topology of a category
Lawvere–Tierney topology of a topos
Point set topology
Trivial topology
Electronics
Topology (electronics), a configuration of electronic components
Computing
Network topology, configurations of computer networks
Logical topology, the arrangement of devices on a computer network and how they communicate with one another
Geospatial data
Geospatial topology, the study or science of places with applications in earth science, geography, human geography, and geomorphology
In geographic information systems and their data structures, topology and planar enforcement are the storing of a border line between two neighboring areas (and the border point between two connecting lines) only once. Thus, any rounding errors might move the border, but will not lead to gaps or overlaps between the areas.
Also in cartography, a topological map is a greatly simplified map that preserves the mathematical topology while sacrificing scale and shape
Topology is often confused with the geographic meaning of topography (originally the study of places). The confusion may be a factor in topographies having become c
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https://en.wikipedia.org/wiki/Institute%20for%20Research%20in%20Fundamental%20Sciences
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The Institute for Research in Fundamental Sciences (IPM; , Pazhuheshgah-e Daneshhai-ye Boniadi), previously Institute for Studies in Theoretical Physics and Mathematics, is an advanced public research institute in Tehran, Iran. IPM is directed by Mohammad-Javad Larijani, its original founder. The institute was the first Iranian organization to connect to the Internet and provide internet service to the nation. It is the domain name registry of .ir domain names.
The institute's activities are directed along several routes:
The institute conducts research along the lines that led to its inception, both independently and in cooperation with other research institutes inside the country and abroad.
The institute carries out conferences as well as joint research projects, and exchanges researchers to establish links with other research institutes and scientific communities within and outside Iran.
The institute provides facilities as well as financial support and opportunity for sabbaticals for researchers belonging to other institutes and universities.
The institute tries to provide the atmosphere necessary for attracting Iranian researchers and scientists from around the world.
The institute conducts graduate study programs to train researchers in areas where the institute is interested to increase the number of manpower.
The institute publicizes its scientific findings of IPM through books, journals, and scientific gatherings.
The institute provides scientific and cultur
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https://en.wikipedia.org/wiki/Volume%20%28disambiguation%29
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Volume is the quantity of space an object occupies in a 3D space.
Volume may also refer to:
Physics
Volume (thermodynamics)
Computing
Volume (computing), a storage area with a single filesystem, typically resident on a single partition of a hard disk
Volume (video game), a 2015 video game by Mike Bithell
Volumetric datasets (3D discretely sampled data, typically a 3D scalar field), which can be visualized with:
Volume rendering
Volume mesh
Isosurface
The Volume, the soundstage in the StageCraft on-set virtual production visual effects technology
Publishing
Volume (bibliography), a physical book; the term is typically used to identify a single book that is part of a larger collection, but may also refer to a codex
Volume (magazine), a 1990s UK music magazine
Volume Magazine, quarterly architecture magazine
Volume! The French Journal of Popular Music Studies, an academic journal
Music
Volume may refer to a sound level assessment, such as:
Amplitude
Loudness
Dynamics (music)
The Volumes, a 1960s American musical group
Volumes, an American progressive metalcore band
Other uses
Volume (finance), the number of shares or contracts traded in a security or an entire market during a given period of time
Volume (film), a 2012 short film directed by Mahalia Belo
See also
"Twenty volumes", a non-scientific description of the concentration of a solution of hydrogen peroxide
Volume form, used in mathematics
Volume One (disambiguation)
Volume Two (disambiguation)
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https://en.wikipedia.org/wiki/Feature%20%28machine%20learning%29
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In machine learning and pattern recognition, a feature is an individual measurable property or characteristic of a phenomenon. Choosing informative, discriminating and independent features is a crucial element of effective algorithms in pattern recognition, classification and regression. Features are usually numeric, but structural features such as strings and graphs are used in syntactic pattern recognition. The concept of "feature" is related to that of explanatory variable used in statistical techniques such as linear regression.
Feature types
In feature engineering, two types of features are commonly used: numerical and categorical.
Numerical features are continuous values that can be measured on a scale. Examples of numerical features include age, height, weight, and income. Numerical features can be used in machine learning algorithms directly.
Categorical features are discrete values that can be grouped into categories. Examples of categorical features include gender, color, and zip code. Categorical features typically need to be converted to numerical features before they can be used in machine learning algorithms. This can be done using a variety of techniques, such as one-hot encoding, label encoding, and ordinal encoding.
The type of feature that is used in feature engineering depends on the specific machine learning algorithm that is being used. Some machine learning algorithms, such as decision trees, can handle both numerical and categorical features. Other
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https://en.wikipedia.org/wiki/Language%20identification%20in%20the%20limit
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Language identification in the limit is a formal model for inductive inference of formal languages, mainly by computers (see machine learning and induction of regular languages). It was introduced by E. Mark Gold in a technical report and a journal article with the same title.
In this model, a teacher provides to a learner some presentation (i.e. a sequence of strings) of some formal language. The learning is seen as an infinite process. Each time the learner reads an element of the presentation, it should provide a representation (e.g. a formal grammar) for the language.
Gold defines that a learner can identify in the limit a class of languages if, given any presentation of any language in the class, the learner will produce only a finite number of wrong representations, and then stick with the correct representation. However, the learner need not be able to announce its correctness; and the teacher might present a counterexample to any representation arbitrarily long after.
Gold defined two types of presentations:
Text (positive information): an enumeration of all strings the language consists of.
Complete presentation (positive and negative information): an enumeration of all possible strings, each with a label indicating if the string belongs to the language or not.
Learnability
This model is an early attempt to formally capture the notion of learnability.
Gold's journal article introduces for contrast the stronger models
Finite identification (where the learner h
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https://en.wikipedia.org/wiki/Thio-
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The prefix thio-, when applied to a chemical, such as an ion, means that an oxygen atom in the compound has been replaced by a sulfur atom. This term is often used in organic chemistry. For example, from the word ether, referring to an oxygen-containing compound having the general chemical structure , where R and R′ are organic functional groups and O is an oxygen atom, comes the word thioether, which refers to an analogous compound with the general structure , where S is a sulfur atom covalently bonded to two organic groups. A chemical reaction involving the replacement of oxygen to sulfur is called thionation or thiation.
Thio- can be prefixed with di- and tri- in chemical nomenclature.
The word derives (which occurs in Greek epic poetry as and may come from the same root as Latin (Indo-European dh-w) and may have originally meant "fumigation substance".)
Examples
Thioamide
Thiocyanate
Thioether
Thioketone
Thiol
Thiophene
Thiourea
Thiosulfate
See also
Organosulfur compounds
IUPAC nomenclature of organic chemistry
References
Chemistry prefixes
Prefixes
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https://en.wikipedia.org/wiki/Lene%20Hau
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Lene Vestergaard Hau (; born November 13, 1959) is a Danish physicist and educator. She is the Mallinckrodt Professor of Physics and of Applied Physics at Harvard University.
In 1999, she led a Harvard University team who, by use of a Bose–Einstein condensate, succeeded in slowing a beam of light to about 17 metres per second, and, in 2001, was able to stop a beam completely. Later work based on these experiments led to the transfer of light to matter, then from matter back into light, a process with important implications for quantum encryption and quantum computing. More recent work has involved research into novel interactions between ultracold atoms and nanoscopic-scale systems. In addition to teaching physics and applied physics, she has taught Energy Science at Harvard, involving photovoltaic cells, nuclear power, batteries, and photosynthesis. In addition to her own experiments and research, she is often invited to speak at international conferences, and is involved in structuring the science policies of various institutions. She was keynote speaker at EliteForsk-konferencen 2013 ("Elite Research Conference") in Copenhagen, which was attended by government ministers, as well as senior science policy and research developers in Denmark.
In acknowledgment of her many achievements, Discover Magazine recognized her in 2002 as one of the 50 most important women in science.
Early life, family and education
Hau was born in Vejle, Denmark.
Hau earned her bachelor's degree
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https://en.wikipedia.org/wiki/Fock%20matrix
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In the Hartree–Fock method of quantum mechanics, the Fock matrix is a matrix approximating the single-electron energy operator of a given quantum system in a given set of basis vectors.
It is most often formed in computational chemistry when attempting to solve the Roothaan equations for an atomic or molecular system. The Fock matrix is actually an approximation to the true Hamiltonian operator of the quantum system. It includes the effects of electron-electron repulsion only in an average way. Because the Fock operator is a one-electron operator, it does not include the electron correlation energy.
The Fock matrix is defined by the Fock operator. In its general form the Fock operator writes:
Where i runs over the total N spin orbitals. In the closed-shell case, it can be simplified by considering only the spatial orbitals. Noting that the terms are duplicated and the exchange terms are null between different spins.
For the restricted case which assumes closed-shell orbitals and single-
determinantal wavefunctions, the Fock operator for the i-th electron is given by:
where:
is the Fock operator for the i-th electron in the system,
is the one-electron Hamiltonian for the i-th electron,
is the number of electrons and is the number of occupied orbitals in the closed-shell system,
is the Coulomb operator, defining the repulsive force between the j-th and i-th electrons in the system,
is the exchange operator, defining the quantum effect produced by exchanging two
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https://en.wikipedia.org/wiki/Oded%20Golan
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Oded Golan () (born 1951 in Tel Aviv) is an Israeli engineer, entrepreneur, and antiquities collector. He owns one of the largest collections of Biblical archaeology in the world.
Biography
Oded Golan is the son of an engineer and a professor of microbiology. He served as an officer in the Israel Defense Forces before studying industrial and management engineering at the Technion, graduating with honors. Since childhood, Golan has had a keen interest in archeology and antiquities. At the age of 10, during a visit to the ancient site of Tel Hatzor, he discovered the world’s oldest dictionary, which was later published by Professor Yigael Yadin. At the age of 12, Golan participated in excavations at Masada.
Antiquity collection
Golan's collection, amassed over a period of more than 50 years, contains thousands of archaeological artifacts, the vast majority of which were purchased from antiquities dealers, mostly in East Jerusalem.
Golan’s collection includes a wide range of artifacts which together represent the culture of Israel and TransJordan from the fifth millennium BCE to the fifth century AD. Among the items that attracted international attention is the James Ossuary, the bone box possibly used to intern the bones of James, brother of Jesus.
Controversy
In June 2003, Golan was accused by the Israel Antiquities Authority (IAA) of involvement in the forgery of one half of the James Ossuary inscription, the Jehoash Inscription and other items. Golan denied any involve
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https://en.wikipedia.org/wiki/DeWitt%20notation
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Physics often deals with classical models where the dynamical variables are a collection of functions
{φα}α over a d-dimensional space/spacetime manifold M where α is the "flavor" index. This involves functionals over the φs, functional derivatives, functional integrals, etc. From a functional point of view this is equivalent to working with an infinite-dimensional smooth manifold where its points are an assignment of a function for each α, and the procedure is in analogy with differential geometry where the coordinates for a point x of the manifold M are φα(x).
In the DeWitt notation''' (named after theoretical physicist Bryce DeWitt), φα(x) is written as φi where i is now understood as an index covering both α and x.
So, given a smooth functional A, A,i stands for the functional derivative
as a functional of φ''. In other words, a "1-form" field over the infinite dimensional "functional manifold".
In integrals, the Einstein summation convention is used. Alternatively,
References
Quantum field theory
Mathematical notation
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https://en.wikipedia.org/wiki/Solid-phase%20synthesis
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In chemistry, solid-phase synthesis is a method in which molecules are covalently bound on a solid support material and synthesised step-by-step in a single reaction vessel utilising selective protecting group chemistry. Benefits compared with normal synthesis in a liquid state include:
High efficiency and throughput
Increased simplicity and speed
The reaction can be driven to completion and high yields through the use of excess reagent. In this method, building blocks are protected at all reactive functional groups. The order of functional group reactions can be controlled by the order of deprotection. This method is used for the synthesis of peptides, deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and other molecules that need to be synthesised in a certain alignment. More recently, this method has also been used in combinatorial chemistry and other synthetic applications. The process was originally developed in the 1950s and 1960s by Robert Bruce Merrifield in order to synthesise peptide chains, and which was the basis for his 1984 Nobel Prize in Chemistry.
In the basic method of solid-phase synthesis, building blocks that have two functional groups are used. One of the functional groups of the building block is usually protected by a protective group. The starting material is a bead which binds to the building block. At first, this bead is added into the solution of the protected building block and stirred. After the reaction between the bead and the protected
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https://en.wikipedia.org/wiki/Sordaria%20fimicola
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Sordaria fimicola is a species of microscopic fungus. It is commonly found in the feces of herbivores. Sordaria fimicola is often used in introductory biology and mycology labs because it is easy to grow on nutrient agar in dish cultures. The genus Sordaria, closely related to Neurospora and Podospora, is a member of the large class Sordariomycetes, or flask-fungi. The natural habitat of the three species of Sordaria that have been the principal subjects in genetic studies is dung of herbivorous animals. The species S. fimicola is common and worldwide in distribution. The species of Sordaria are similar morphologically, producing black perithecia containing asci with eight dark ascospores in a linear arrangement. These species share a number of characteristics that are advantageous for genetic studies. They all have a short life cycle, usually 7–12 days, and are easily grown in culture. Most species are self-fertile and each strain is isogenic. All kinds of mutants are easily induced and readily obtainable with particular ascospore color mutants. These visual mutants aid in tetrad analysis, especially in analysis of intragenic recombination.
The most common form of S. fimicola is a dark brown. Certain mutants are grey or tan. A common experiment for an introductory biology lab class is to cross one of the mutant types with a wild type and observe the ratio of coloring in the offspring. This experiment illustrates the concepts of genetic inheritance in a haploid organism.
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https://en.wikipedia.org/wiki/Leibniz%20formula%20for%20%CF%80
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In mathematics, the Leibniz formula for , named after Gottfried Wilhelm Leibniz, states that
an alternating series. It is sometimes called the Madhava–Leibniz series as it was first discovered by the Indian mathematician Madhava of Sangamagrama or his followers in the 14th–15th century (see Madhava series), and was later independently rediscovered by James Gregory in 1671 and Leibniz in 1673. The Taylor series for the inverse tangent function, often called Gregory's series, is:
The Leibniz formula is the special case
It also is the Dirichlet -series of the non-principal Dirichlet character of modulus 4 evaluated at , and, therefore, the value of the Dirichlet beta function.
Proofs
Proof 1
Considering only the integral in the last term, we have:
Therefore, by the squeeze theorem, as , we are left with the Leibniz series:
Proof 2
Let , when , the series to be converges uniformly, then
Therefore, if approaches so that it is continuous and converges uniformly, the proof is complete, where, the series to be converges by the Leibniz's test, and also, approaches from within the Stolz angle, so from Abel's theorem this is correct.
Convergence
Leibniz's formula converges extremely slowly: it exhibits sublinear convergence. Calculating to 10 correct decimal places using direct summation of the series requires precisely five billion terms because for (one needs to apply Calabrese error bound). To get 4 correct decimal places (error of 0.00005) one needs 5000
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https://en.wikipedia.org/wiki/NWChem
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NWChem is an ab initio computational chemistry software package which includes quantum chemical and molecular dynamics functionality.
It was designed to run on high-performance parallel supercomputers as well as conventional workstation clusters. It aims to be scalable both in its ability to treat large problems efficiently, and in its usage of available parallel computing resources. NWChem has been developed by the Molecular Sciences Software group of the Theory, Modeling & Simulation program of the Environmental Molecular Sciences Laboratory (EMSL) at the Pacific Northwest National Laboratory (PNNL). The early implementation was funded by the EMSL Construction Project.
NWChem is currently being redesigned and reimplemented for exascale computing platforms (NWChemEx ).
Capabilities
Molecular mechanics
Molecular dynamics
Hartree–Fock (self-consistent field method)
Density functional theory
Time-dependent density functional theory
Post-Hartree–Fock methods, including MP2 in the resolution of identity approximation (RI-MP2), multiconfigurational self-consistent-field (MCSCF) theory, selected configuration interaction (CI), Møller–Plesset perturbation theory (MP2, MP3, MP4), configuration interaction (CISD, CISDT, CISDTQ), and coupled cluster theory (CCSD, CCSDT, CCSDTQ, EOMCCSD, EOMCCSDT, EOMCCSDTQ). The Tensor Contraction Engine, or TCE, provides most of the functionality for the correlated methods, and can be used to develop additional many-body methods using a P
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https://en.wikipedia.org/wiki/Wallis%20product
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In mathematics, the Wallis product for , published in 1656 by John Wallis, states that
Proof using integration
Wallis derived this infinite product using interpolation, though his method is not regarded as rigorous. A modern derivation can be found by examining for even and odd values of , and noting that for large , increasing by 1 results in a change that becomes ever smaller as increases. Let
(This is a form of Wallis' integrals.) Integrate by parts:
Now, we make two variable substitutions for convenience to obtain:
We obtain values for and for later use.
Now, we calculate for even values by repeatedly applying the recurrence relation result from the integration by parts. Eventually, we end get down to , which we have calculated.
Repeating the process for odd values ,
We make the following observation, based on the fact that
Dividing by :
, where the equality comes from our recurrence relation.
By the squeeze theorem,
Proof using Laplace's method
See the main page on Gaussian integral.
Proof using Euler's infinite product for the sine function
While the proof above is typically featured in modern calculus textbooks, the Wallis product is, in retrospect, an easy corollary of the later Euler infinite product for the sine function.
Let :
Relation to Stirling's approximation
Stirling's approximation for the factorial function asserts that
Consider now the finite approximations to the Wallis product, obtained by taking the first terms in the prod
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https://en.wikipedia.org/wiki/Operator-precedence%20parser
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In computer science, an operator precedence parser is a bottom-up parser that interprets an operator-precedence grammar. For example, most calculators use operator precedence parsers to convert from the human-readable infix notation relying on order of operations to a format that is optimized for evaluation such as Reverse Polish notation (RPN).
Edsger Dijkstra's shunting yard algorithm is commonly used to implement operator precedence parsers.
Relationship to other parsers
An operator-precedence parser is a simple shift-reduce parser that is capable of parsing a subset of LR(1) grammars. More precisely, the operator-precedence parser can parse all LR(1) grammars where two consecutive nonterminals and epsilon never appear in the right-hand side of any rule.
Operator-precedence parsers are not used often in practice; however they do have some properties that make them useful within a larger design. First, they are simple enough to write by hand, which is not generally the case with more sophisticated right shift-reduce parsers. Second, they can be written to consult an operator table at run time, which makes them suitable for languages that can add to or change their operators while parsing. (An example is Haskell, which allows user-defined infix operators with custom associativity and precedence; consequentially, an operator-precedence parser must be run on the program after parsing of all referenced modules.)
Raku sandwiches an operator-precedence parser between tw
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https://en.wikipedia.org/wiki/Spiral%20%28disambiguation%29
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A spiral is a curve which emanates from a central point, getting progressively farther away as it revolves around the point.
Spiral may also refer to:
Science, mathematics and art
Spiral galaxy, a type of galaxy in astronomy
Spiral Dynamics, a theory of human development
Spiral cleavage, a type of cleavage in embryonic development
Victoria and Albert Museum Spiral, a proposed (abandoned in 2004) controversial extension to the museum
Spiral (arts alliance), an African-American art collective
Spiral (publisher), a New Zealand women's publisher and art collective
Spiral model, a software development process
Transport
Spiral (railway), a technique employed by railways to ascend steep hills
Spiral bridge, a similar technique for roads
9K114 Shturm, an anti-tank missile that is known under the NATO reporting name as AT-6 Spiral
Mikoyan-Gurevich MiG-105 Spiral, a Soviet spaceplane
Spiral dive, a type of generally undesirable and accidental descent manoeuvre in an aircraft
Film and television
Spiral (1978 film), a Polish film
Spiral (1998 film), a Japanese film
Uzumaki (film), or Spiral, a 2000 Japanese film
Spiral (2007 film), an American film
Spiral (2014 film), a Russian film
Spiral (2019 film), a Canadian film
Spiral (2021 film), an American film, part of the Saw horror franchise
Spiral (TV series), English title of French thriller series Engrenages
Spiral: The Bonds of Reasoning, a 2002 Japanese anime series
"Spiral" (Buffy the Vampire Slayer), a 2001 T
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https://en.wikipedia.org/wiki/Hat%20%28disambiguation%29
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A hat is an item of clothing worn on the head.
Hat or HAT may also refer to:
Film
The Hat (film), a 1999 short film by Michèle Cournoyer
The Hat, a 1912 film by Rollin S. Sturgeon
The Hat, a 1963 film by Faith Hubley and John Hubley
Mathematics
Hat matrix, a mathematical operation in statistics
Hat operator, notation used in mathematics
Hat function, alternate name for the triangular function
A solution to the einstein problem, a shape nicknamed the "hat"
Organisations
Handball Association of Thailand, governing body of handball in Thailand
Hutchison Asia Telecom Group, a business division in telecommunications
Hellenic Aeronautical Technologies, a Greek aeroplane manufacturer
Helicopter Air Transport, a defunct American helicopter operator
People
Jack McVitie (1932–1967), known as Jack "The Hat", English gangster
Les Miles (born 1953), known as The Hat, American football coach
Jan Åge Solstad (born 1969), known as Hat, former vocalist for the Norwegian black metal band Gorgoroth
Places
Hať, Moravian-Silesian Region, Czech Republic
Hat, Azerbaijan
Hat, Nepal
Hat, Berehove Raion, Ukraine
Hat District, Al Mahrah Governorate, Yemen
Hat Island (disambiguation)
Science
Human African trypanosomiasis (sleeping sickness)
HAt, symbol for hydrogen astatide
Histone acetyltransferase, an enzyme class
HAT medium, used in microbiology and immunology, for example in culturing hybridoma cells
Hungarian-made Automated Telescope, used in the HATNet Project
Technol
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https://en.wikipedia.org/wiki/Heinrich%20Gr%C3%A4fe
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Heinrich Gräfe or Graefe (March 3, 1802 – July 22, 1868), German educator, was born at Buttstädt in Saxe-Weimar.
He studied mathematics and theology at Jena, and in 1823 obtained a curacy in the town church of Weimar. He was transferred to Jena as rector of the town school in 1825; in 1840 he was also appointed extraordinary professor of the science of education (Pädagogik) in that university; and in 1842 he became head of the Burgersckule (middle class school) in Kassel.
After reorganizing the schools of the town, he became director of the new Realschule in 1843; and, devoting himself to the interests of educational reform in the Electorate of Hesse, he became in 1849 a member of the school commission, and also entered the house of representatives, where he made himself somewhat formidable as an agitator.
In 1852 for having been implicated in the September riots and in the movement against the unpopular minister Hassenpflug, who had dissolved the school commission, he was condemned to three years imprisonment, a sentence afterwards reduced to one of twelve months. On his release he withdrew to Geneva, where he engaged at the International Boarding School La Châtelaine (owner and director Achilles Roediger) until 1855, when he was appointed director of the Realschule in der Altstadt at Bremen until his death on 21 July 1868. His successor was Franz Georg Philipp Buchenau.
Besides being the author of many text-books and occasional papers on educational subjects, he wrote D
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https://en.wikipedia.org/wiki/BESS%20%28experiment%29
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BESS is a particle physics experiment carried by a balloon. BESS stands for Balloon-borne Experiment with Superconducting Spectrometer. BESS is a series of experiments that started in 1993, and a later incarnation, BESS-Polar, circled the Antarctic from December 13 to December 21, 2004, for a total of 8 days 17 hours and 2 minutes. This joint Japanese and American project is supported by the Laboratory for High Energy Astrophysics (LHEA) at NASA's GSFC and the KEK.
Overview
The mission of this experiment is to detect antiparticles in the cosmic radiation at high altitudes. It is therefore designed to be carried aloft by balloon. The central detection device is a magnetic spectrometer, that is used to identify all electrically charged particles crossing its main detection aperture. Mission members are working on improving the sensitivity and precision of this system with each new launch.
Scientific goals
Theories of the beginning of the Universe are based on the currently-known laws of particle physics, where matter is created from energy in such a way that equal amounts of particles and antiparticles are produced. If this is so, then an amount of antimatter equal to the amount of currently visible matter must exist—though there is an equal possibility the bulk of the antimatter may have been annihilated due to the mechanism of CP violation. The aim of BESS therefore is to quantify the amount of antiparticles in the local cosmos and so help to decide between these alternativ
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https://en.wikipedia.org/wiki/Bruce%20Bellas
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Bruce Harry Bellas (July 7, 1909 – July 1974) was an American photographer. He was influential in his work with male physiques and nudes. Bellas was well known under the pseudonym Bruce of Los Angeles.
History and influence
Bruce Harry Bellas was born in Alliance, Nebraska on July 7, 1909. He worked as a chemistry teacher there until 1947, when he began photographing bodybuilders in Los Angeles, California, beginning with taking pictures of bodybuilding competitions. In 1956, Bellas launched his own magazine, The Male Figure. Among physique photographers, Bellas' work was noted for having a distinctly campy, tongue-in-cheek sensibility. Bellas also produced a number of early homoerotic 8 mm films with titles such as Cowboy Washup and Big Gun for Hire.
Bellas was known to travel around the country, finding new models to photograph and also personally delivering nude photographs to customers, since they were liable to be seized by postal inspectors if sent through the mail.
An extensive archive of Bellas' nude male physique photographs exists today, largely intact. His impact on physique photography is largely felt and recognized, and the works of Robert Mapplethorpe, Herb Ritts, and Bruce Weber are widely considered to be influenced by Bellas' pioneering style. In 1990, the Wessel O'Connor Gallery in New York and the Jan Kesner Gallery in Los Angeles both exhibited a wide array of Bellas' work, furthering modern recognition of his impact.
Bellas died while on vacation in
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https://en.wikipedia.org/wiki/Irish%20Mathematical%20Society
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The Irish Mathematical Society () or IMS is the main professional organisation for mathematicians in Ireland. The society aims to further mathematics and mathematical research in Ireland. Its membership is international, but it mainly represents mathematicians in universities and other third level institutes in Ireland. It publishes a bulletin, The Bulletin of the Irish Mathematical Society, twice per year and runs an annual conference in September.
The society was founded on 14 April 1976 at a meeting in Trinity College, Dublin when a constitution drafted by D McQuillan, John T. Lewis and Trevor West was accepted. It is a member organization in the European Mathematical Society. Since 2020, it has been the adhering organization for Ireland's membership of the International Mathematical Union. The logo was designed by Irish mathematician Desmond MacHale.
Bulletin of the Irish Mathematical Society
The Bulletin of the Irish Mathematical Society is a journal that has been published since 1986, and was preceded by the Newsletter of the Irish Mathematical Society. It accepts articles that are of interest to both Society members and the wider mathematical community. Articles include original research articles, expository survey articles, biographical and historical articles, classroom notes and book reviews. It also includes a problem page. Articles are available online.
Officers
Current officers of the society are listed in the bulletin.
References
External links
IMS we
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https://en.wikipedia.org/wiki/Suffix%20array
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In computer science, a suffix array is a sorted array of all suffixes of a string. It is a data structure used in, among others, full-text indices, data-compression algorithms, and the field of bibliometrics.
Suffix arrays were introduced by as a simple, space efficient alternative to suffix trees. They had independently been discovered by Gaston Gonnet in 1987 under the name PAT array .
gave the first in-place time suffix array construction algorithm that is optimal both in time and space, where in-place means that the algorithm only needs additional space beyond the input string and the output suffix array.
Enhanced suffix arrays (ESAs) are suffix arrays with additional tables that reproduce the full functionality of suffix trees preserving the same time and memory complexity.
The suffix array for a subset of all suffixes of a string is called sparse suffix array. Multiple probabilistic algorithms have been developed to minimize the additional memory usage including an optimal time and memory algorithm.
Definition
Let be an -string and let denote the substring of ranging from to inclusive.
The suffix array of is now defined to be an array of integers providing the starting positions of suffixes of in lexicographical order. This means, an entry contains the starting position of the -th smallest suffix in and thus for all : .
Each suffix of shows up in exactly once. Suffixes are simple strings. These strings are sorted (as in a paper dictionary), before
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https://en.wikipedia.org/wiki/Franti%C5%A1ek%20K%C5%99i%C5%BE%C3%ADk
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František Křižík (; 8 July 1847 – 22 January 1941) was a Czech inventor, electrical engineer, and entrepreneur.
Biography
Křižík was born into a family in Plánice. In spite of his background, Křižík managed in 1866 to study engineering at the Technical University of Prague ČVUT.
Křižík is considered the pioneer of practical electrical engineering and in electrification of Bohemia and Austro-Hungarian empire. At the time he was often compared to Thomas Edison. In 1878 Křižík invented a remotely operated signaling device to protect against collision between trains. Křižík's cores are magnetic
solenoids cores shaped so as to ensure an approximately uniform pull in different positions in the solenoid.
His first experiments in Plzeň resulted in the invention in 1880 of the automatic electric arc lamp, the so-called "Plzen Lamp" which was displayed at the International Exposition of Electricity in Paris in 1881. This lamp, with self-adjusting brushes, won the gold medal from among 50 similar devices. Later he successfully defended his patent against Werner Siemens claim to have created it first. His lamps were successfully used in many cities for street lighting. The restored and fully functional patented arc lamp with automated electrode adjustment can be viewed at the Museum of Pilsen. In 1894, he designed an electric musical fountain illuminated by coloured lamps, one of the most popular attractions at the General National Exhibition in Lviv.
In 1884 Křižík set up his own c
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https://en.wikipedia.org/wiki/Neuroscience%20and%20intelligence
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Neuroscience and intelligence refers to the various neurological factors that are partly responsible for the variation of intelligence within species or between different species. A large amount of research in this area has been focused on the neural basis of human intelligence. Historic approaches to studying the neuroscience of intelligence consisted of correlating external head parameters, for example head circumference, to intelligence. Post-mortem measures of brain weight and brain volume have also been used. More recent methodologies focus on examining correlates of intelligence within the living brain using techniques such as magnetic resonance imaging (MRI), functional MRI (fMRI), electroencephalography (EEG), positron emission tomography and other non-invasive measures of brain structure and activity.
Researchers have been able to identify correlates of intelligence within the brain and its functioning. These include overall brain volume, grey matter volume, white matter volume, white matter integrity, cortical thickness and neural efficiency.
Analyses of the parameters of intellectual systems, patterns of their emergence and evolution, distinctive features, and the constants and limits of their structures and functions made it possible to measure and compare the capacity of communications (~100 m/s), to quantify the number of components in intellectual systems (~1011 neurons), and to calculate the number of successful links responsible for cooperation (~1014 sy
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https://en.wikipedia.org/wiki/Von%20K%C3%A1rm%C3%A1n%20%28disambiguation%29
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Theodore von Kármán was a Hungarian-American mathematician, aerospace engineer and physicist.
Von Kármán may also refer to:
Von Kármán (lunar crater)
Von Kármán (Martian crater)
Von Karman Institute for Fluid Dynamics
Von Kármán ogive
Von Kármán constant
von Kármán Wind Turbulence Model
Theodore von Karman Medal
See also
Born–von Karman boundary condition
Karman, surname
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https://en.wikipedia.org/wiki/Round
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Round or rounds may refer to:
Mathematics and science
The contour of a closed curve or surface with no sharp corners, such as an ellipse, circle, rounded rectangle, cant, or sphere
Rounding, the shortening of a number to reduce the number of significant figures it contains
Round number, a number that ends with one or more zeroes
Roundness (geology), the smoothness of clastic particles
Roundedness, rounding of lips when pronouncing vowels
Labialization, rounding of lips when pronouncing consonants
Music
Round (music), a type of musical composition
Rounds (album), a 2003 album by Four Tet
Places
The Round, a defunct theatre in the Ouseburn Valley, Newcastle upon Tyne, England
Round Point, a point on the north coast of King George Island, South Shetland Islands
Grand Rounds Scenic Byway, a parkway system in Minneapolis
Rounds Mountain, a peak in the Taconic Mountains, United States
Round Mountain (disambiguation), several places
Round Valley (disambiguation), several places
Repeated activities
Round (boxing), a time period within a boxing match
Round (cryptography), a basic crypto transformation
Grand rounds, a ritual in medical education and inpatient care
Round of drinks, a traditional method of paying in a drinking establishment
Funding round, a discrete round of investment in a business
Doing the rounds or patrol, moving through an area at regular or irregular intervals
Round (Theosophy), a planetary cycle of reincarnation in Theosophy
Round (domi
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https://en.wikipedia.org/wiki/Afshar%20experiment
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The Afshar experiment is a variation of the double-slit experiment in quantum mechanics, devised and carried out by Shahriar Afshar in 2004. In the experiment, light generated by a laser passes through two closely spaced pinholes, and is refocused by a lens so that the image of each pinhole falls on a separate single-photon detector. In addition, a grid of thin wires is placed just before the lens on the dark fringes of an interference pattern.
Afshar claimed that the experiment gives information about which path a photon takes through the apparatus, while simultaneously allowing interference between the paths to be observed. According to Afshar, this violates the complementarity principle of quantum mechanics.
The experiment has been analyzed and repeated by a number of investigators. There are several theories that explain the effect without violating complementarity. John G. Cramer claims the experiment provides evidence for the transactional interpretation of quantum mechanics over other interpretations.
History
Shahriar Afshar's experimental work was done initially at the Institute for Radiation-Induced Mass Studies (IRIMS) in Boston and later reproduced at Harvard University, while he was there as a visiting researcher. The results were first presented at a seminar at Harvard in March 2004. The experiment was featured as the cover story in the July 24, 2004 edition of the popular science magazine New Scientist endorsed by professor John G. Cramer of the University
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https://en.wikipedia.org/wiki/BER
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BER may refer to:
Biology and medicine
Basal electrical rhythm, spontaneous rhythmic slow action potentials that some smooth muscles of the GI tract display
Base excision repair, DNA repair pathway
Benign early repolarization
Blossom end rot, plant disorder
Computing
Basic Encoding Rules, a set of rules for encoding data that is described using the ASN.1 standard, for the purpose of transmission to a different computer system
Bit error rate, the ratio between the number of incorrect bits transmitted to the total number of bits (E.800)
Bleeding edge software release, an incremental, often daily distribution of the next version of a software package which has not yet been declared "stable"
Places
Bermuda, British overseas territory, IOC and UNDP code
Bohai Economic Rim, China
Transport
Air Berlin, defunct German airline with ICAO code BER
BER is the IATA code for Berlin Brandenburg Airport, opened in October 2020. It was formerly a metro area code encompassing the following airports in the Berlin region, Germany:
Berlin-Tegel Airport (TXL), closed in November 2020, after the opening of BER
Berlin-Tempelhof Airport (THF), closed in 2008
Berlin-Schönefeld Airport (SXF), closed in October 2020, but became part of Berlin Brandenburg Airport
Other
Berber language (ISO 639 alpha-3, ber)
Beyond economic repair, rating of a damaged item
Block Exemption Regulation (EU), Regulation published by the European Commission regarding European Union competition law
Buildi
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https://en.wikipedia.org/wiki/WME
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WME may refer to:
Windows Media Encoder
Wireless Multimedia Extensions
Wintermute Engine, a graphical adventure game engine by Dead:Code software
William Morris Endeavor, a talent agency conglomerate
Web-based Mathematics Education
Working Memory Element in the Rete algorithm
The IATA code for Mount Keith Airport in Western Australia
Waze Map Editor
National Rail station code for Woodmansterne railway station in London
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https://en.wikipedia.org/wiki/Soma%20%28biology%29
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In cellular neuroscience, the soma (: somata or somas; ), perikaryon (: perikarya), neurocyton, or cell body is the bulbous, non-process portion of a neuron or other brain cell type, containing the cell nucleus. Although it is often used to refer to neurons, it can also refer to other cell types as well, including astrocytes, oligodendrocytes, and microglia. There are many different specialized types of neurons, and their sizes vary from as small as about 5 micrometres to over 10 millimetres for some of the smallest and largest neurons of invertebrates, respectively.
The soma of a neuron (i.e., the main part of the neuron in which the dendrites branch off of) contains many organelles, including granules called Nissl granules, which are composed largely of rough endoplasmic reticulum and free polyribosomes. The cell nucleus is a key feature of the soma. The nucleus is the source of most of the RNA that is produced in neurons. In general, most proteins are produced from mRNAs that do not travel far from the cell nucleus. This creates a challenge for supplying new proteins to axon endings that can be a meter or more away from the soma. Axons contain microtubule-associated motor proteins that transport protein-containing vesicles between the soma and the synapses at the axon terminals. Such transport of molecules towards and away from the soma maintains critical cell functions. In case of neurons, the soma receives a large number of inhibitory synapses, which can regulate the ac
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