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https://en.wikipedia.org/wiki/Michael%20J.%20C.%20Gordon
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Michael John Caldwell Gordon (28 February 1948 – 22 August 2017) was a British computer scientist.
Life
Mike Gordon was born in Ripon, Yorkshire, England. He attended Dartington Hall School and Bedales School. In 1966, he was accepted to study engineering at Gonville and Caius College, University of Cambridge, but transferred to mathematics. During his studies, in 1969 he worked at the National Physical Laboratory in London during the summer, gaining his first exposure to computers.
Gordon studied for his PhD degree at University of Edinburgh, supervised by Rod Burstall, finishing in 1973 with a thesis entitled Evaluation and Denotation of Pure LISP Programs. He was invited to Stanford University in California by John McCarthy, the inventor of LISP, to work in his Artificial Intelligence Laboratory there. Gordon worked at the Cambridge University Computer Laboratory from 1981, initially as a lecturer, promoted to Reader in 1988 and Professor in 1996.
He was elected a Fellow of the Royal Society in 1994, and in 2008 a two-day research meeting on Tools and Techniques for Verification of System Infrastructure was held there in honour of his 60th birthday.
Mike Gordon was married to Avra Cohn, a PhD student of Robin Milner at the University of Edinburgh, and they undertook research together.
He died in Cambridge after a brief illness and is survived by his wife and two sons.
Work
Gordon led the development of the HOL theorem prover. The HOL system is an environment for int
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https://en.wikipedia.org/wiki/David%20May%20%28computer%20scientist%29
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Michael David May FRS FREng (born 24 February 1951) is a British computer scientist. He is a Professor in the Department of Computer Science at the University of Bristol and founder of XMOS Semiconductor, serving until February 2014 as the chief technology officer.
May was lead architect for the transputer. As of 2017, he holds 56 patents, all in microprocessors and multi-processing.
Life and career
May was born in Holmfirth, Yorkshire, England and attended Queen Elizabeth Grammar School, Wakefield. From 1969 to 1972 he was a student at King's College, Cambridge, University of Cambridge, at first studying Mathematics and then Computer Science in the University of Cambridge Mathematical Laboratory, now the University of Cambridge Computer Laboratory.
He moved to the University of Warwick and started research in robotics. The challenges of implementing sensing and control systems led him to design and implement an early concurrent programming language, EPL, which ran on a cluster of single-board microcomputers connected by serial communication links. This early work brought him into contact with Tony Hoare and Iann Barron: one of the founders of Inmos.
When Inmos was formed in 1978, May joined to work on microcomputer architecture, becoming lead architect of the transputer and designer of the associated programming language Occam. This extended his earlier work and was also influenced by Tony Hoare, who was at the time working on CSP and acting as a consultant to Inmos.
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https://en.wikipedia.org/wiki/Vittorio%20Giardino
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Vittorio Giardino (born December 24, 1946) is an Italian comic artist.
Biography
Giardino was born in Bologna, where he graduated in electrical engineering in 1969. At the age of 30, he decided to leave his job and devote himself to comics. Two years later his first short story, "Pax Romana", was published in La Città Futura, a weekly magazine published by the Italian Communist Youth Federation and edited by Luigi Bernardi.
In 1982 Giardino created a new character: Max Fridman, an ex-secret agent involved in the political struggle in 1930s Europe. His first adventure, Hungarian Rhapsody was serialized in the first four issues of magazine Orient Express, bringing Giardino in the limelight of the international comic scene. Max Fridman adventures have been published in 18 countries. Some of the prizes the series won include Lucca Festival's and Brussels' St. Michel.
Starting in 1984, Giardino produced a number of short stories for the Italian magazine Comic Art, where he introduced Little Ego, a young and sexy girl inspired by Winsor McCay's Little Nemo who stars in one-page dreamy erotic stories.
In 1991 Giardino created a new character, Jonas Fink for the Il Grifo magazine. Jonas is a young Jew in 1950's Prague whose father is arrested by the communist police. He and his mother have to cope with the discrimination and oppression of the Stalinist regime. The book, collected as A Jew in Communist Prague, won the Angoulème Alfred prize for best foreign work in 1995 as well a
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https://en.wikipedia.org/wiki/Semicubical%20parabola
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In mathematics, a cuspidal cubic or semicubical parabola is an algebraic plane curve that has an implicit equation of the form
(with ) in some Cartesian coordinate system.
Solving for leads to the explicit form
which imply that every real point satisfies . The exponent explains the term semicubical parabola. (A parabola can be described by the equation .)
Solving the implicit equation for yields a second explicit form
The parametric equation
can also be deduced from the implicit equation by putting
The semicubical parabolas have a cuspidal singularity; hence the name of cuspidal cubic.
The arc length of the curve was calculated by the English mathematician William Neile and published in 1657 (see section History).
Properties of semicubical parabolas
Similarity
Any semicubical parabola is similar to the semicubical unit parabola
Proof: The similarity (uniform scaling) maps the semicubical parabola onto the curve with
Singularity
The parametric representation is regular except at point At point the curve has a singularity (cusp). The proof follows from the tangent vector Only for this vector has zero length.
Tangents
Differentiating the semicubical unit parabola one gets at point of the upper branch the equation of the tangent:
This tangent intersects the lower branch at exactly one further point with coordinates
(Proving this statement one should use the fact, that the tangent meets the curve at twice.)
Arclength
Determining the arclength
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https://en.wikipedia.org/wiki/Primitive%20%28phylogenetics%29
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In phylogenetics, a primitive (or ancestral) character, trait, or feature of a lineage or taxon is one that is inherited from the common ancestor of a clade (or clade group) and has undergone little change since. Conversely, a trait that appears within the clade group (that is, is present in any subgroup within the clade but not all) is called advanced or derived. A clade is a group of organisms that consists of a common ancestor and all its lineal descendants.
A primitive trait is the original condition of that trait in the common ancestor; advanced indicates a notable change from the original condition. These terms in biology contain no judgement about the sophistication, superiority, value or adaptiveness of the named trait. "Primitive" in biology means only that the character appeared first in the common ancestor of a clade group and has been passed on largely intact to more recent members of the clade. "Advanced" means the character has evolved within a later subgroup of the clade.
Phylogenetics is utilized to determine evolutionary relationships and relatedness, to ultimately depict accurate evolutionary lineages. Evolutionary relatedness between living species can be connected by descent from common ancestry. These evolutionary lineages can thereby be portrayed through a phylogenetic tree, or cladogram, where varying relatedness amongst species is evidently depicted. Through this tree, organisms can be categorized by divergence from the common ancestor, and prim
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https://en.wikipedia.org/wiki/Matthias%20Felleisen
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Matthias Felleisen is a German-American computer science professor and author. He grew up in Germany and immigrated to the US in his twenties.
He received his PhD from Indiana University under the direction of Daniel P. Friedman.
After serving as professor for 14 years in the Computer Science Department of Rice University, Felleisen joined the Khoury College of Computer Sciences at Northeastern University in Boston, Massachusetts as Trustee Professor.
Felleisen's interests include programming languages, including software tools, program design, software contracts, and many more. In the 1990s, Felleisen launched PLT and TeachScheme! (later ProgramByDesign and eventually giving rise to the Bootstrap project
) with the goal of teaching program-design principles to beginners and to explore the use of Scheme to produce large systems. As part of this effort, he authored How to Design Programs (MIT Press, 2001) with Findler, Flatt, and Krishnamurthi.
For his dissertation Felleisen developed an extension of Church's lambda calculus with assignment statements and continuation operators. The dissertation re-proved the Church-Rosser theorem and the Curry-Feys Standardization Theorem for these extended calculus. It thus established a novel form of operational semantics for higher-order functional languages with imperative extensions. Its most well-known application is for a proof of type safety, worked out with his PhD student Andrew Wright.
Tim Griffin showed a few years later th
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https://en.wikipedia.org/wiki/Civil%20engineering%20and%20infrastructure%20repair%20in%20New%20Orleans%20after%20Hurricane%20Katrina
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This article covers the levee system and infrastructure repairs in New Orleans, Louisiana following Hurricane Katrina.
Though Hurricane Katrina did not deal the city of New Orleans a direct hit on August 29, 2005, the associated storm surge precipitated catastrophic failures of the levees and flood walls. The Mississippi River Gulf Outlet ("MR-GO") breached its levees in approximately 15 places. The major levee breaches in the city include the 17th Street Canal levee, the London Avenue Canal, and the wide, navigable Industrial Canal, which left approximately 80% of the city flooded.
While ownership, definition of requirements, operation and maintenance of the system belonged to the Orleans Levee Board, federal responsibility for New Orleans' flood protection design and construction belongs by federal mandate to the US Army Corps of Engineers.
Flooding from the breaches put the majority of the city under water for days, in many places for weeks. The Corps made emergency repairs to breaches, as pumps worked at draining the city. Hurricane Rita brushed the city nearly a month later, causing reflooding of some areas, most significantly from water flowing through incompletely repaired levee breaches.
Background
Flooding due to rain and storms has long been an issue since the New Orleans' early settlement due to the city's location on a delta marsh, much of which sits below sea level. The city is surrounded by the Mississippi River to the south, Lake Pontchartrain to the north
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https://en.wikipedia.org/wiki/Fin%20%28disambiguation%29
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A fin is an appendage used to produce lift and thrust or to steer while traveling in water, air, or other fluid media.
Fin, FIN, or Fins may also refer to:
Biology
Fish fin, an anatomical feature of fish
Fin fish, fish that possess fins
Fin whale (Balaenoptera physalus)
People
Fín (died 604), Gaelic princess, wife of Oswiu of Northumbria
Finns, people from Finland
Fin Bartels (born 1987), German football midfielder
Fin Donnelly (born 1966), Canadian politician
Fin Dow-Smith, (born 1988), British songwriter
Fin Leavell, American musician
Fin Taylor, (born 1990), English stand-up comedian
Fin Wilson (1888–1959), American professional baseball pitcher
Henri Fin (born 1950), French cyclist
Legendary and fictional characters
Fin (comics), the name of two characters from Marvel Comics
Fin (troll), in Danish legend
Fin the Whale, the mascot of the Vancouver Canucks
Fin Tutuola, a fictional character on the TV drama Law & Order: Special Victims Unit
Places
Fin, Iran, a city
Fins, Somme, a commune in France
Fin District, Iran
Fin Garden, in Kashan, Iran
Fin Island, in British Columbia, Canada
Fin Rural District, Iran
Finland
Music
Fin (band), an English indie rock band
Fin (John Talabot album), 2012
Fin (Syd album), 2017
"Fin" (song), a 2006 song by Supergrass
"Fin", 1986 song by Akina Nakamori
"Fin", by Christie Front Drive from Christie Front Drive, 1997
"Fin", a song by Nebula from the 2003 album Atomic Ritual
"Fins" (song), a 1979 song by
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https://en.wikipedia.org/wiki/Metastability%20in%20the%20brain
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In the field of computational neuroscience, the theory of metastability refers to the human brain's ability to integrate several functional parts and to produce neural oscillations in a cooperative and coordinated manner, providing the basis for conscious activity.
Metastability, a state in which signals (such as oscillatory waves) fall outside their natural equilibrium state but persist for an extended period of time, is a principle that describes the brain's ability to make sense out of seemingly random environmental cues. In the past 25 years, interest in metastability and the underlying framework of nonlinear dynamics has been fueled by advancements in the methods by which computers model brain activity.
Overview
EEG measures the gross electrical activity of the brain that can be observed on the surface of the skull. In the metastability theory, EEG outputs produce oscillations that can be described as having identifiable patterns that correlate with each other at certain frequencies. Each neuron in a neuronal network normally outputs a dynamical oscillatory waveform, but also has the ability to output a chaotic waveform. When neurons are integrated into the neural network by interfacing neurons with each other, the dynamical oscillations created by each neuron can be combined to form highly predictable EEG oscillations.
By identifying these correlations and the individual neurons that contribute to predictable EEG oscillations, scientists can determine which cor
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https://en.wikipedia.org/wiki/Plumbite
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In chemistry, plumbite is the oxyanion or hydrated forms, or any salt containing this anion. In these salts, lead is in the oxidation state +2. It is the traditional term for the IUPAC name plumbate(II).
For example, lead(II) oxide (PbO) dissolves in alkali to form salts containing the anion (hydrogen plumbite):
Lead(II) hydroxide also dissolves in excess alkali to form the anion (hexahydroxyplumbate(II)):
The plumbite ion is a weak reducing agent. When it functions as one, it is oxidized to the plumbate ion.
See also
Plumbate
Lead
Lead(II) oxide
References
Lead(II) compounds
Oxyanions
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https://en.wikipedia.org/wiki/Artin%E2%80%93Schreier%20theory
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In mathematics, Artin–Schreier theory is a branch of Galois theory, specifically a positive characteristic analogue of Kummer theory, for Galois extensions of degree equal to the characteristic p. introduced Artin–Schreier theory for extensions of prime degree p, and generalized it to extensions of prime power degree pn.
If K is a field of characteristic p, a prime number, any polynomial of the form
for in K, is called an Artin–Schreier polynomial. When for all , this polynomial is irreducible in K[X], and its splitting field over K is a cyclic extension of K of degree p. This follows since for any root β, the numbers β + i, for , form all the roots—by Fermat's little theorem—so the splitting field is .
Conversely, any Galois extension of K of degree p equal to the characteristic of K is the splitting field of an Artin–Schreier polynomial. This can be proved using additive counterparts of the methods involved in Kummer theory, such as Hilbert's theorem 90 and additive Galois cohomology. These extensions are called Artin–Schreier extensions.
Artin–Schreier extensions play a role in the theory of solvability by radicals, in characteristic p, representing one of the possible classes of extensions in a solvable chain.
They also play a part in the theory of abelian varieties and their isogenies. In characteristic p, an isogeny of degree p of abelian varieties must, for their function fields, give either an Artin–Schreier extension or a purely inseparable extension.
A
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https://en.wikipedia.org/wiki/Jovino%20Santos%20Neto
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Jovino Santos Neto (born September 18, 1954) is a Seattle-based Brazilian-American jazz pianist, flutist, composer, arranger, educator and record producer.
Career
Jovino Santos Neto started playing piano at age 13 and by 16 was playing keyboards in a band called the Vacancy Group in Bangu, Rio de Janeiro. He earned a degree in Biology, from the Federal University of Rio de Janeiro, and later from Macdonald College of McGill University in Montreal, Quebec, Canada.
In 1977, he joined the group led by Brazilian composer Hermeto Pascoal, working as a pianist, flutist, composer, arranger and producer. Since leaving Hermeto's group in 1992 and relocating to the United States, Santos Neto has released several albums. He has toured internationally as the leader of his own ensemble and with musicians such as Airto Moreira, Flora Purim, and Mike Marshall.
Santos Neto teaches at Seattle's Cornish College of the Arts and is a frequent teacher at Jazz Camp West.
Discography
1998: Caboclo
2000: Ao Vivo em Olympia (Live in Olympia, Washington)
2001: Balaio (Basket) (Malandro)
2003: Canto do Rio
2003: Serenata with Mike Marshall
2005: Brazil Duets with Mike Marshall
2006: Roda Carioca
2008: Alma do Nordeste (Soul of the Northeast)
2010: Veja o Som
2011: Current
Awards
Artist Trust Fellowship, 2001
IAJE/ASCAP (International Association for Jazz Education/American Society of Composers, Authors and Publishers Commission) for an established composer, 2002
Chamber Mu
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https://en.wikipedia.org/wiki/Swedish%20Institute%20of%20Computer%20Science
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RISE SICS (previously Swedish Institute of Computer Science) is a leading research institute for applied information and communication technology in Sweden, founded in 1985.
It explores the digitalization of products, services and businesses.
In January 2005, SICS had about 88 employees, of which 77 were researchers, 30 with PhD degrees. , SICS had about 200 employees, of which 160 were researchers, 83 with PhD degrees. The institute is headquartered in the Kista district of Stockholm, with the main office in the Electrum building.
Software
Several well-known software packages have been developed at SICS:
Contiki, an operating system for small-memory embedded devices
Delegent, an authorization server
Distributed Interactive Virtual Environment or DIVE in short
lwIP, a TCP/IP stack for embedded systems
Oz-Mozart, a multi-platform programming system
Nemesis, a concept exokernel operating system
Protothreads, light-weight stackless threads
Quintus Prolog and SICStus Prolog, Prolog implementations
Simics, a full-system simulator originally developed at SICS
uIP, a TCP/IP stack for embedded systems
Academic output
The research at SICS results in approximately 100 refereed publications in academic journals, conferences and workshops per year. Around 2-4 SICS researchers receive higher academic degrees per year, and 1-3 persons move to academia for tenured positions.
SICS was ranked as the 15th most acknowledged computer science research institution in the world in an article
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https://en.wikipedia.org/wiki/Terminal%20alkene
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In organic chemistry, terminal alkenes (alpha-olefins, α-olefins, or 1-alkenes) are a family of organic compounds which are alkenes (also known as olefins) with a chemical formula , distinguished by having a double bond at the primary, alpha (α), or 1- position. This location of a double bond enhances the reactivity of the compound and makes it useful for a number of applications.
Classification
There are two types of alpha-olefins, branched and linear (or normal). The chemical properties of branched alpha-olefins with a branch at either the second (vinylidene) or the third carbon number are significantly different from the properties of linear alpha-olefins and those with branches on the fourth carbon number and further from the start of the chain.
Examples of linear alpha-olefins are propene, but-1-ene and dec-1-ene. An example of a branched alpha-olefin is isobutylene.
Production
A variety of methods are employed for production of alpha-olefins. One class of methods starts with ethylene which is either dimerized or oligomerized. These conversions are respectively effected by the alphabutol process, giving 1-butene, and the Shell Higher Olefin Process which gives a range of alpha-olefins. The former is based on titanium-based catalysts, and the latter relies on nickel-based catalysts. A whole other approach to alpha-olefins, especially long chain derivatives, involves cracking of waxes:
R-CH2-CH2-CH2-CH2-R' -> R-CH=CH2 + CH2=CH-R' + H2
In the Pacol process, linear
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https://en.wikipedia.org/wiki/Floer%20homology
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In mathematics, Floer homology is a tool for studying symplectic geometry and low-dimensional topology. Floer homology is a novel invariant that arises as an infinite-dimensional analogue of finite-dimensional Morse homology. Andreas Floer introduced the first version of Floer homology, now called Lagrangian Floer homology, in his proof of the Arnold conjecture in symplectic geometry. Floer also developed a closely related theory for Lagrangian submanifolds of a symplectic manifold. A third construction, also due to Floer, associates homology groups to closed three-dimensional manifolds using the Yang–Mills functional. These constructions and their descendants play a fundamental role in current investigations into the topology of symplectic and contact manifolds as well as (smooth) three- and four-dimensional manifolds.
Floer homology is typically defined by associating to the object of interest an infinite-dimensional manifold and a real valued function on it. In the symplectic version, this is the free loop space of a symplectic manifold with the symplectic action functional. For the (instanton) version for three-manifolds, it is the space of SU(2)-connections on a three-dimensional manifold with the Chern–Simons functional. Loosely speaking, Floer homology is the Morse homology of the function on the infinite-dimensional manifold. A Floer chain complex is formed from the abelian group spanned by the critical points of the function (or possibly certain collections
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https://en.wikipedia.org/wiki/Philip%20Kitcher
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Philip Stuart Kitcher (born 20 February 1947) is a British philosopher who is John Dewey Professor Emeritus of philosophy at Columbia University. He specialises in the philosophy of science, the philosophy of biology, the philosophy of mathematics, the philosophy of literature, and more recently pragmatism.
Life and career
Born in London, Kitcher spent his early life in Eastbourne, East Sussex, on the south coast of the United Kingdom, where another distinguished philosopher of an earlier generation (A. J. Ayer) was also at school. Kitcher himself went to school at Christ's Hospital, Horsham, West Sussex. He earned his BA in mathematics/history and philosophy of science from Christ's College, Cambridge, in 1969, and his PhD in history and philosophy of science from Princeton University in 1974, where he worked closely with Carl Hempel and Thomas Kuhn.
Kitcher is currently John Dewey Professor of Philosophy Emeritus at Columbia University. As chair of Columbia's Contemporary Civilization program (part of its undergraduate Core Curriculum), he also held the James R. Barker Professorship of Contemporary Civilization. Before moving to Columbia, Kitcher held tenure-track positions at the University of Vermont, the University of Minnesota, and University of California, San Diego, where he held the position of Presidential Professor of Philosophy.
Kitcher is past president of the American Philosophical Association. In 2002, Kitcher was named a fellow of the American Academy of A
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https://en.wikipedia.org/wiki/George%20Lawson%20%28botanist%29
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George Lawson (October 12, 1827 – November 10, 1895) was a Scottish-Canadian botanist who is considered the "father of Canadian botany".
Born in Scotland, in 1858, he was appointed the Professor of Chemistry and Natural History at Queen's University. He helped to create one of Canada's first botanical gardens.
In 1868, he became Professor of Chemistry and Mineralogy at Dalhousie University.
He was a charter member of the Royal Society of Canada and from 1887 to 1888 was its president.
References
External links
19th-century Canadian botanists
Scottish curators
Scottish librarians
1827 births
1895 deaths
Botanists active in North America
Academics of the University of Edinburgh
Alumni of the University of Edinburgh
Academic staff of the Dalhousie University
Academic staff of Queen's University at Kingston
Scottish emigrants to pre-Confederation Ontario
Pre-Confederation Ontario people
People from Dundee
People from Fife
Scottish scholars and academics
19th-century Scottish botanists
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https://en.wikipedia.org/wiki/O%28n%29
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In mathematics, O(n) may refer to:
O(n), the orthogonal group
Big O notation, indicating the order of growth of some quantity as a function of n or the limiting behavior of a function, e.g. in computational complexity theory
The nth tensor power of Serre's twisting sheaf
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https://en.wikipedia.org/wiki/Extremal%20combinatorics
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Extremal combinatorics is a field of combinatorics, which is itself a part of mathematics. Extremal combinatorics studies how large or how small a collection of finite objects (numbers, graphs, vectors, sets, etc.) can be, if it has to satisfy certain restrictions.
Much of extremal combinatorics concerns classes of sets; this is called extremal set theory. For instance, in an n-element set, what is the largest number of k-element subsets that can pairwise intersect one another? What is the largest number of subsets of which none contains any other? The latter question is answered by Sperner's theorem, which gave rise to much of extremal set theory.
Another kind of example: How many people can be invited to a party where among each three people there are two who know each other and two who don't know each other? Ramsey theory shows that at most five persons can attend such a party. Or, suppose we are given a finite set of nonzero integers, and are asked to mark as large a subset as possible of this set under the restriction that the sum of any two marked integers cannot be marked. It appears that (independent of what the given integers actually are) we can always mark at least one-third of them.
See also
Extremal graph theory
Sauer–Shelah lemma
Erdős–Ko–Rado theorem
Kruskal–Katona theorem
Fisher's inequality
Union-closed sets conjecture
References
.
.
.
Combinatorial optimization
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https://en.wikipedia.org/wiki/Isotachophoresis
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Isotachophoresis (ITP) is a technique in analytical chemistry used for selective separation and concentration of ionic analytes. It is a form of electrophoresis; charged analytes are separated based on ionic mobility, a quantity which tells how fast an ion migrates through an electric field.
Overview
In conventional ITP separations, a discontinuous buffer system is used. The sample is introduced between a zone of fast leading electrolyte (LE) and a zone of slow terminating (or: trailing) electrolyte (TE). Usually, the LE and the TE have a common counterion, but the co-ions (having charges with the same sign as the analytes of interest) are different: the LE is defined by co-ions with high ionic mobility, while the TE is defined by co-ions with low ionic mobility. The analytes of interest have intermediate ionic mobility. Application of an electric potential results in a low electrical field in the leading electrolyte and a high electrical field in the terminating electrolyte. Analyte ions situated in the TE zone will migrate faster than the surrounding TE co-ions, while analyte ions situated in the LE will migrate slower; the result is that analytes are focused at the LE/TE interface.
ITP is a displacement method: focusing ions of a certain kind displace other ions. If present in sufficient amounts, focusing analyte ions can displace all electrolyte co-ions, reaching a plateau concentration. Multiple analytes with sufficiently different ionic mobilities will form multiple p
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https://en.wikipedia.org/wiki/Nitrosyl%20fluoride
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Nitrosyl fluoride (NOF) is a covalently bonded nitrosyl compound.
Physical properties
The compound is a colorless gas, with bent molecular shape. The VSEPR model explains this geometry via a lone-pair of electrons on the nitrogen atom.
Chemistry
Nitrosyl fluoride is typically produced by direct reaction of nitric oxide and fluorine, although halogenation with a perfluorinated metal salt is also possible. The compound is a highly reactive fluorinating agent that converts many metals to their fluorides, releasing nitric oxide in the process:
n NOF + M → MFn + n NO
For this reason, aqueous NOF solutions, like aqua regia, are powerful solvents for metals.
Absent an oxidizable metal, NOF reacts with water to form nitrous acid, which then disproportionates to nitric acid:
NOF + H2O → HNO2 + HF
3 HNO2 → HNO3 + 2 NO + H2O
These reactions occur in both acidic and basic solutions.
Nitrosyl fluoride also forms salt-like adducts with Lewis-acidic fluorides; for example, BF3 reacts to give NOBF4. Similarly, the compound nitrosylates compounds with a free proton; thus alcohols convert to nitrites:
ROH + NOF → RONO + HF
Uses
Nitrosyl fluoride is used as a solvent and as a fluorinating and nitrating agent in organic synthesis. It has also been proposed as an oxidizer in rocket propellants.
References
External links
WebBook page for NOF
National Pollutant Inventory - Fluoride and compounds fact sheet
Nitrosyl compounds
Oxyfluorides
Fluorinating agents
Nitrogen(III) co
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https://en.wikipedia.org/wiki/Thionyl%20group
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The thionyl group is SO, a sulfur atom plus an oxygen atom.
It occurs in compounds such as thionyl fluoride, SOF2.
Thionyl chloride, SOCl2, is a common reagent used in organic synthesis to convert carboxylic acids to acyl chlorides.
In organic chemistry, the thionyl group is known as a sulfoxide group or sulfinyl group, and has the general structure RS(=O)R'.
See also
Sulfuryl
References
Functional groups
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https://en.wikipedia.org/wiki/Sulfuryl
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In inorganic chemistry, the sulfuryl group is a functional group consisting of a sulfur atom covalently bound to two oxygen atoms ().
It occurs in compounds such as sulfuryl chloride, and sulfuryl fluoride, .
In organic chemistry, this group is found in sulfones () and sulfonyl halides (), where it is called the sulfonyl group.
References
Functional groups
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https://en.wikipedia.org/wiki/Drilling%20and%20blasting
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Drilling and blasting is the controlled use of explosives and other methods, such as gas pressure blasting pyrotechnics, to break rock for excavation. It is practiced most often in mining, quarrying and civil engineering such as dam, tunnel or road construction. The result of rock blasting is often known as a rock cut.
Drilling and blasting currently utilizes many different varieties of explosives with different compositions and performance properties. Higher velocity explosives are used for relatively hard rock in order to shatter and break the rock, while low velocity explosives are used in soft rocks to generate more gas pressure and a greater heaving effect. For instance, an early 20th-century blasting manual compared the effects of black powder to that of a wedge, and dynamite to that of a hammer. The most commonly used explosives in mining today are ANFO based blends due to lower cost than dynamite.
Before the advent of tunnel boring machines (TBMs), drilling and blasting was the only economical way of excavating long tunnels through hard rock, where digging is not possible. Even today, the method is still used in the construction of tunnels, such as in the construction of the Lötschberg Base Tunnel. The decision whether to construct a tunnel using a TBM or using a drill and blast method includes a number of factors. Tunnel length is a key issue that needs to be addressed because large TBMs for a rock tunnel have a high capital cost, but because they are usually qui
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https://en.wikipedia.org/wiki/Saclay
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Saclay () is a commune in the southwestern suburbs of Paris, France. It is located from the centre of Paris. It had a population of 3,067 in 2006. It is best known for the large scientific facility CEA Saclay, mostly dealing with nuclear and particle physics. Inhabitants of Saclay are known as Saclaysiens.
Transport
Saclay is served by no station of the Paris Métro (RER), or suburban rail network. The closest station to Saclay is Le Guichet station on Paris RER line B. This station is located in the neighboring commune of Orsay, to the south of the town center of Saclay.
See also
Communes of the Essonne department
Plateau de Saclay
References
External links
Official website
Community blog
Mayors of Essonne Association
1846 establishments in France
Communes of Essonne
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https://en.wikipedia.org/wiki/Alchemy%20%28disambiguation%29
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Alchemy was an early protoscientific practice. It may also refer to:
Regional forms
Alchemy and chemistry in medieval Islam
Chinese alchemy
Indian alchemy, or Rasayana
Entertainment and literature
Alchemy (comics), a Marvel character
Alchemy (video game), a 2001 video game by PopCap Games
Alchemy (novel), a 2004 novel by Margaret Mahy
Doctor Alchemy, a DC Comics super-villain
Alchemy (film), 2005 film
Music
Songs
Alchemy, a song by Starset, from the album Horizons
Albums
Alchemy (Disclosure album), 2023
Alchemy (Leah Andreone album), 1998
Alchemy (Richard Lloyd album), 1979
Alchemy (Third Ear Band album), 1969
Alchemy (Yngwie Malmsteen album), 1999
Alchemy: An Index of Possibilities (1985), a 1985 album by David Sylvian
Alchemy: Dire Straits Live (1984)
Record labels
Alchemy Records (Japan), a record label
Alchemy Records (U.S.), a record label
Television
"Alchemy" (Eureka), an episode of Eureka
Alchemy (Fullmetal Alchemist), an ability in the Fullmetal Alchemist manga/anime series
Hardware and software
Alchemy (Adobe), Adobe software project
Alchemy (microarchitecture), a series of embedded processors originally from Alchemy Semiconductor, later owned by multiple other semiconductor companies
Sometimes used as shortcut for SQLAlchemy, an object-relational mapper for the Python programming language
AlchemyAPI, a company that uses machine learning to do natural language processing
Other
Alchemy (event), a regional Burning Man event in La Fayette, Georgia, US
Alchem
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https://en.wikipedia.org/wiki/Elmer%20FEM%20solver
|
Elmer is a computational tool for multi-physics problems. It has been developed by CSC in collaboration with Finnish universities, research laboratories and industry. Elmer FEM solver is free and open-source software, subject to the requirements of the GNU General Public License (GPL), version 2 or any later.
Elmer includes physical models of fluid dynamics, structural mechanics, electromagnetics, heat transfer and acoustics, for example. These are described by partial differential equations which Elmer solves by the Finite Element Method (FEM).
Elmer comprises several different parts:
ElmerGrid – A mesh conversion tool, which can be used to convert differing mesh formats into Elmer-suitable meshes.
ElmerGUI – A graphical interface which can be used on an existing mesh to assign physical models, this generates a "case file" which describes the problem to be solved. Does not show the whole ElmerSolver functionality in GUI.
ElmerSolver – The numerical solver which performs the finite element calculations, using the mesh and case files.
ElmerPost – A post-processing/visualisation module. (Development stopped in favour of other post-processing tools such as ParaView, VisIt, etc.)
The different parts of Elmer software may be used independently. Whilst the main module is the ElmerSolver tool, which includes many sophisticated features for physical model solving, the additional components are required to create a full workflow. For pre- and post-processing other tools, such
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https://en.wikipedia.org/wiki/David%20Cheriton
|
David Ross Cheriton (born March 29, 1951) is a Canadian computer scientist, businessman, philanthropist, and venture capitalist. He is a computer science professor at Stanford University, where he founded and leads the Distributed Systems Group.
He is a distributed computing and computer networking expert, with insight into identifying big market opportunities and building the architectures needed to address such opportunities. He has founded and invested in technology companies, including Google, where he was among the first angel investors; VMware, where he was an early investor; and Arista, where he was cofounder and chief scientist. He has funded at least 20 companies.
Cheriton was ranked by Forbes with an estimated net worth of US$8.8 billion, as of April 2021. He has made contributions to education, with a $25 million donation to support graduate studies and research in the School of Computer Science (subsequently renamed David R. Cheriton School of Computer Science) at the University of Waterloo, a $7.5 million donation to the University of British Columbia, and a $12 million endowment in 2016 to Stanford University to support Computer Science faculty, graduate fellowships, and undergraduate scholarships.
Education
Born in Vancouver, British Columbia, Canada, Cheriton attended public schools in the Highlands neighborhood of Edmonton, Alberta, Canada.
He briefly attended the University of Alberta where he had applied for both mathematics and music. He was rejected b
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https://en.wikipedia.org/wiki/Bob%20Braden
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Robert Braden (28 January 1934 – April 2018) was an American computer scientist who played a role in the development of the Internet. His research interests included end-to-end network protocols, especially in the transport and network layers.
Career
Braden received a Bachelor of Engineering Physics from Cornell University in 1957, and a Master of Science in physics from Stanford University in 1962. After graduating, he worked at Stanford and Carnegie Mellon University. He taught programming and operating systems courses at Stanford, Carnegie Mellon, and also UCLA, where he moved next.
He remained at UCLA for 18 years, 16 of them at the campus computing center. He spent 1981–1982 at the Computer Science Department of University College London. While there, he wrote the first relay system connecting the Internet with the U.K. academic X.25 network.
He joined the networking research group at the Information Sciences Institute (ISI) in 1986, and was a project leader in the Computer Networks Division. He was named an ISI Fellow in 2001.
Professional contributions
While at UCLA, Braden was responsible for attaching UCLA's IBM 360/91 supercomputer to the ARPAnet, beginning in 1970. He was active in the ARPAnet Network Working Group, contributing to the design of the File Transfer Protocol in particular.
In 1978, he became a member of the Internet Working Group, which developed TCP/IP, and began development of a TCP/IP implementation for UCLA's IBM system. The UCLA IBM softwar
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https://en.wikipedia.org/wiki/Faraday%20paradox%20%28electrochemistry%29
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The Faraday paradox was a once inexplicable aspect of the reaction between nitric acid and steel. Around 1830, the English scientist Michael Faraday found that diluted nitric acid would attack steel, but concentrated nitric acid would not. The attempt to explain this discovery led to advances in electrochemistry.
Passivation
Faraday's electrochemical paradox arises from his famous experiment of 1833. Concentrated nitric acid had been synthesized and although Faraday did not have a pH meter (the pH scale would not be developed for another seventy years), Faraday knew from various tests (e.g. taste and time of dissolution of calcite chips) that concentrated nitric acid was a much stronger acid than dilute nitric acid. Thus, when he placed the iron in the dilute acid, gas (now known to be hydrogen) was evolved from the surface and the iron dissolved. When he placed the iron in the concentrated nitric acid, he expected that it would dissolve at a higher rate, but no attack was observed. He then scratched the surface and a burst of bubbles was generated but then ceased. He stated that the surface had become "passive" and, therefore, he correctly assumed that the surface was oxidized and became covered with a protective oxide film. However, the oxide film did not dissolve and the attack continued in the concentrated nitric acid. This became known as Faraday's electrochemical paradox, and was not solved until 1989.
The key to resolving the paradox is passivation. When the ac
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https://en.wikipedia.org/wiki/Precision%20rectifier
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The precision rectifier is a configuration obtained with an operational amplifier in order to have a circuit behave like an ideal diode and rectifier. It is very useful for high-precision signal processing. With the help of a precision rectifier the high-precision signal processing can be done very easily.
The op-amp-based precision rectifier should not be confused with the power MOSFET-based active rectification ideal diode.
Basic circuit
The basic circuit implementing such a feature is shown on the right, where can be any load. When the input voltage is negative, there is a negative voltage on the diode, so it works like an open circuit, no current flows through the load, and the output voltage is zero. When the input is positive, it is amplified by the operational amplifier, which switches the diode on. Current flows through the load and, because of the feedback, the output voltage is equal to the input voltage.
The actual threshold of the super diode is very close to zero, but is not zero. It equals the actual threshold of the diode, divided by the gain of the operational amplifier.
This basic configuration has a problem, so it is not commonly used. When the input becomes (even slightly) negative, the operational amplifier runs open-loop, as there is no feedback signal through the diode. For a typical operational amplifier with high open-loop gain, the output saturates. If the input then becomes positive again, the op-amp has to get out of the saturated state befo
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https://en.wikipedia.org/wiki/Kenneth%20N.%20Ogle
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Kenneth N. Ogle (1902-1968) was a scientist of human vision. He was born in Colorado, and attended the public school and college at Colorado Springs. In 1925, Ogle earned a bachelor's degree from Colorado College cum laude. After graduation from college and selection of physics as a career, Ogle spent two years at Dartmouth College, a year at the University of Minnesota, and then returned to Dartmouth College for his Ph.D. degree, awarded in 1930. He was later awarded an honorary medical degree by the University of Uppsala in Sweden.
Ogle remained at Dartmouth Eye Institute to which he was appointed by Adelbert Ames, Jr. from 1930 until 1947 where he spent much of his working life until the Institute was discontinued. In 1947 Ogle became a member of the staff of the Mayo Clinic in Rochester, Minnesota, in the Section of Biophysics, working intimately with the Eye Section.
Ogle's research work was largely in the fields of optics and human binocular vision.
In 1967, he won the Tillyer Medal, awarded by the Optical Society of America. He died less than two months after retiring from the Mayo Clinic.
Selected bibliography
Ogle, K. N. (1950). Researches in binocular vision. New York: Hafner Publishing Company.
Ogle, K. N. (1953). Precision and validity in stereoscopic depth perception from double images. Journal of the Optical Society of America, 43, 906-913.
Ogle, K. N. (1962). Ocular dominance and binocular retinal rivalry. In H. Davson (Ed.), Visual optics and the optic
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https://en.wikipedia.org/wiki/Parameterized%20post-Newtonian%20formalism
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In physics, precisely in the study of the theory of general relativity and many alternatives to it, the post-Newtonian formalism is a calculational tool that expresses Einstein's (nonlinear) equations of gravity in terms of the lowest-order deviations from Newton's law of universal gravitation. This allows approximations to Einstein's equations to be made in the case of weak fields. Higher-order terms can be added to increase accuracy, but for strong fields, it may be preferable to solve the complete equations numerically. Some of these post-Newtonian approximations are expansions in a small parameter, which is the ratio of the velocity of the matter forming the gravitational field to the speed of light, which in this case is better called the speed of gravity. In the limit, when the fundamental speed of gravity becomes infinite, the post-Newtonian expansion reduces to Newton's law of gravity.
The parameterized post-Newtonian formalism or PPN formalism, is a version of this formulation that explicitly details the parameters in which a general theory of gravity can differ from Newtonian gravity. It is used as a tool to compare Newtonian and Einsteinian gravity in the limit in which the gravitational field is weak and generated by objects moving slowly compared to the speed of light. In general, PPN formalism can be applied to all metric theories of gravitation in which all bodies satisfy the Einstein equivalence principle (EEP). The speed of light remains constant in PPN for
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https://en.wikipedia.org/wiki/Hole%20argument
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In general relativity, the hole argument is an apparent paradox that much troubled Albert Einstein while developing his famous field equations.
Some philosophers of physics take the argument to raise a problem for manifold substantialism, a doctrine that the manifold of events in spacetime is a "substance" which exists independently of the metric field defined on it or the matter within it. Other philosophers and physicists disagree with this interpretation, and view the argument as a confusion about gauge invariance and gauge fixing instead.
Einstein's hole argument
In a usual field equation, knowing the source of the field, and the boundary conditions, determines the field everywhere. For example, if we are given the current and charge density and appropriate boundary conditions, Maxwell's equations determine the electric and magnetic fields. They do not determine the vector potential though, because the vector potential depends on an arbitrary choice of gauge.
Einstein noticed that if the equations of gravity are generally covariant, then the metric cannot be determined uniquely by its sources as a function of the coordinates of spacetime. As an example: consider a gravitational source, such as the Sun. Then there is some gravitational field described by a metric g(r). Now perform a coordinate transformation r r' where r' is the same as r for points which are inside the Sun but r' is different from r outside the Sun. The coordinate description of the interior of the Sun
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https://en.wikipedia.org/wiki/Blas%20Cabrera%20Navarro
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Blas Cabrera Navarro (born September 21, 1946 in Paris, France) is a Stanley G. Wojcicki Professor of Physics at Stanford University best known for his experiment in search of magnetic monopoles. He is the son of Spanish physicist Nicolás Cabrera and the grandson of Blas Cabrera Felipe, also a Spanish physicist.
Blas Cabrera received his B.S. from the University of Virginia in 1968 and in 1975 got his Ph.D. from Stanford University after defending his thesis The Use of Superconducting Shields for Generating Ultra Low Magnetic Field Regions and Several Related Experiments, under advisors William M. Fairbank and William O. Hamilton.
On the night of February 14, 1982, his detector recorded an event which had the perfect signature hypothesized for a magnetic monopole. After he published his discovery, a number of similar detectors were built by various research groups, and Cabrera's laboratory itself received a large grant to build an improved detector. However, no similar event has been recorded since, and his research group has since dropped the search. He is now a leader of the Cryogenic Dark Matter Search experiment.
In 1995, Cabrera was elected as a fellow of the American Physical Society.
References
1946 births
Living people
Magneticians
21st-century American physicists
University of Virginia alumni
Stanford University alumni
Stanford University Department of Physics faculty
Winners of the Panofsky Prize
Fellows of the American Physical Society
Scientists from Paris
Me
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https://en.wikipedia.org/wiki/Richard%20Bader
|
Richard F. W. Bader (October 15, 1931 – January 15, 2012) was a Canadian quantum chemist, noted for his work on the Atoms in molecules theory. This theory attempts to establish a physical basis for many of the working concepts of chemistry, such as atoms in molecules and bonding, in terms of the topology of the electron density function in three-dimensional space. Alongside the eminent chemist Ronald Gillespie, he had a significant influence on inorganic chemistry education in Canada.
He was born in 1931 in Kitchener, Ontario, Canada. His parents were Albert Bader and Alvina Bader, who immigrated from Switzerland. His father was a butcher at Burns Pride of Canada and his mother was a housekeeper at Kitchener Hospital of Waterloo. He received a scholarship from McMaster University that allowed him to earn a BSC in 1953. His father was his best supporter who encouraged him and taught him to "never quit" his education and his dream. He finished his master's degree in science at McMaster University in 1955. He obtained a PhD (1958) from the Massachusetts Institute of Technology (MIT). He did postdoctoral work at MIT and the University of Cambridge. He was appointed assistant professor in the Department of Chemistry at the University of Ottawa in 1959 and promoted to associate professor in 1962. He moved to McMaster University as associate professor in 1963, became full Professor in 1966 and was Emeritus Professor until 1996.
He was elected a Fellow of the Royal Society of
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https://en.wikipedia.org/wiki/Rvachev%20function
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In mathematics, an R-function, or Rvachev function, is a real-valued function whose sign does not change if none of the signs of its arguments change; that is, its sign is determined solely by the signs of its arguments.
Interpreting positive values as true and negative values as false, an R-function is transformed into a "companion" Boolean function (the two functions are called friends). For instance, the R-function ƒ(x, y) = min(x, y) is one possible friend of the logical conjunction (AND). R-functions are used in computer graphics and geometric modeling in the context of implicit surfaces and the function representation. They also appear in certain boundary-value problems, and are also popular in certain artificial intelligence applications, where they are used in pattern recognition.
R-functions were first proposed by () in 1963, though the name, "R-functions", was given later on by Ekaterina L. Rvacheva-Yushchenko, in memory of their father, Logvin Fedorovich Rvachev ().
See also
Function representation
Slesarenko function (S-function)
Notes
References
Meshfree Modeling and Analysis, R-Functions (University of Wisconsin)
Pattern Recognition Methods Based on Rvachev Functions (Purdue University)
Shape Modeling and Computer Graphics with Real Functions
Non-classical logic
Real analysis
Types of functions
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https://en.wikipedia.org/wiki/Mohammad%20Kaykobad
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Mohammad Kaykobad () is a computer scientist, educator, author, and columnist from Bangladesh. Along with Muhammed Zafar Iqbal, he started the national mathematics olympiad. He was a professor of computer science and engineering in Bangladesh University of Engineering and Technology.
and currently is a faculty member of computer science and engineering in BRAC University.Also a faculty member of University of information technology and Sciences.
Education
In 1970, Kaykobad finished his SSC from Manikganj Govt. High School and in 1972, his HSC from Debendra College. He did his M.S. in Engineering at the Institute of Marine Engineers, Odesa, Ukraine (then in the USSR), in 1979. He did his M.Eng. in computer applications technology at the Asian Institute of Technology, Thailand, in 1982. He did his PhD at the Flinders University of South Australia, in 1986 under the Supervision of Dr FJM Salzborn.
Career
Dr. Kaykobad served as an adviser to ICT Projects for e-Governance in Bangladesh. He was awarded the gold medal for contribution in ICT Education at a ceremony at Bangabandhu International Conference Center by Bangladesh Computer Society and was presented the award by the President of Bangladesh on 26 July 2005. He was recognized as the best coach of ACM International Collegiate Programming Contest by IBM at 26th World Finals of ACM ICPC at Honolulu, Hawaii on 22 March 2002. He researched the Computerization of class scheduling of different universities of Bangladesh which was
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https://en.wikipedia.org/wiki/Mark%20Allen%20Shepherd
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Mark Allen Shepherd (born January 7, 1961) is an actor, best known for his role as Morn on Star Trek: Deep Space Nine. He also appeared as Morn (uncredited) in one episode each of Star Trek: The Next Generation and Star Trek: Voyager.
Biography and career
Shepherd received a Bachelor of Science degree in biology from Roger Williams University in Rhode Island. After graduation, he moved to Southern California and studied at the California Institute of the Arts, focusing on music, film, theater, performance, and interdisciplinary arts.
Shepherd is an artist and has created numerous abstract impressionist paintings, mixing media types into photomosaics. Twenty-four of his works have been used as set dressing on Star Trek: Deep Space Nine.
Shepherd is also a member of Plural Dolt, an absurdist music theater group based in Los Angeles.
In 2009, Shepherd voiced the role of Alex Miller on the fan produced audio series Star Trek: The Continuing Mission.
References
External links
1961 births
Living people
American male film actors
American male television actors
California Institute of the Arts alumni
Roger Williams University alumni
20th-century American male actors
21st-century American male actors
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https://en.wikipedia.org/wiki/Jonathan%20A.%20Jones
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Jonathan A. Jones (born 1967) is a professor in atomic and laser physics at the University of Oxford, and a fellow and tutor in physics at Brasenose College, Oxford.
Education
Jones studied at Corpus Christi College, Oxford, from 1985 to 1989 and St John's College, Oxford, from 1989 to 1992. He received his Doctor of Philosophy degree in 1992 for research on Nuclear magnetic resonance data processing methods supervised by Peter Hore.
Research and career
Although trained in chemistry, he is active in physics, especially for his work on NMR quantum computation for which he was awarded the 2000 Marlow Medal of the Royal Society of Chemistry. His main research interest is in quantum computation.
"Freedom of information" activism
In 2009, Jones joined in making Freedom of Information requests to the Climatic Research Unit following a complaint by blogger Steve McIntyre that the Climatic Research Unit of the University of East Anglia (UEA) had refused to release raw weather station data. Meteorological organisations had allowed the university to use this data on the understanding that it would be kept private, largely due to its commercial value. Jones made a Freedom of Information request for raw data which the university had shared with another researcher, but refused to provide to McIntyre. The university worked with the Met Office to get meteorological organisations to waive confidentiality on raw instrumental data, most failed to respond and two refused. In 2011 the Inform
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https://en.wikipedia.org/wiki/Atomic%20diffusion
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In chemical physics, atomic diffusion is a diffusion process whereby the random, thermally-activated movement of atoms in a solid results in the net transport of atoms. For example, helium atoms inside a balloon can diffuse through the wall of the balloon and escape, resulting in the balloon slowly deflating. Other air molecules (e.g. oxygen, nitrogen) have lower mobilities and thus diffuse more slowly through the balloon wall. There is a concentration gradient in the balloon wall, because the balloon was initially filled with helium, and thus there is plenty of helium on the inside, but there is relatively little helium on the outside (helium is not a major component of air). The rate of transport is governed by the diffusivity and the concentration gradient.
In crystals
In the crystal solid state, diffusion within the crystal lattice occurs by either interstitial or substitutional mechanisms and is referred to as lattice diffusion. In interstitial lattice diffusion, a diffusant (such as C in an iron alloy), will diffuse in between the lattice structure of another crystalline element. In substitutional lattice diffusion (self-diffusion for example), the atom can only move by substituting place with another atom. Substitutional lattice diffusion is often contingent upon the availability of point vacancies throughout the crystal lattice. Diffusing particles migrate from point vacancy to point vacancy by the rapid, essentially random jumping about
(jump diffusion).
Sinc
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https://en.wikipedia.org/wiki/Fluid%20mechanics
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Fluid mechanics is the branch of physics concerned with the mechanics of fluids (liquids, gases, and plasmas) and the forces on them.
It has applications in a wide range of disciplines, including mechanical, aerospace, civil, chemical, and biomedical engineering, as well as geophysics, oceanography, meteorology, astrophysics, and biology.
It can be divided into fluid statics, the study of fluids at rest; and fluid dynamics, the study of the effect of forces on fluid motion.
It is a branch of continuum mechanics, a subject which models matter without using the information that it is made out of atoms; that is, it models matter from a macroscopic viewpoint rather than from microscopic. Fluid mechanics, especially fluid dynamics, is an active field of research, typically mathematically complex. Many problems are partly or wholly unsolved and are best addressed by numerical methods, typically using computers. A modern discipline, called computational fluid dynamics (CFD), is devoted to this approach. Particle image velocimetry, an experimental method for visualizing and analyzing fluid flow, also takes advantage of the highly visual nature of fluid flow.
Brief history
The study of fluid mechanics goes back at least to the days of ancient Greece, when Archimedes investigated fluid statics and buoyancy and formulated his famous law known now as the Archimedes' principle, which was published in his work On Floating Bodies—generally considered to be the first major work on flui
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https://en.wikipedia.org/wiki/Level-spacing%20distribution
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In mathematical physics, level spacing is the difference between consecutive elements in some set of real numbers. In particular, it is the difference between consecutive energy levels or eigenvalues of a matrix or linear operator.
Mathematical physics
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https://en.wikipedia.org/wiki/Fredholm%20determinant
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In mathematics, the Fredholm determinant is a complex-valued function which generalizes the determinant of a finite dimensional linear operator. It is defined for bounded operators on a Hilbert space which differ from the identity operator by a trace-class operator. The function is named after the mathematician Erik Ivar Fredholm.
Fredholm determinants have had many applications in mathematical physics, the most celebrated example being Gábor Szegő's limit formula, proved in response to a question raised by Lars Onsager and C. N. Yang on the spontaneous magnetization of the Ising model.
Definition
Let be a Hilbert space and the set of bounded invertible operators on of the form
, where is a trace-class operator. is a group because
so is trace class if is. It has a natural metric given by
, where is the trace-class norm.
If is a Hilbert space with inner product , then so too is the th exterior power
with inner product
In particular
gives an orthonormal basis of if is an orthonormal basis of .
If is a bounded operator on , then functorially defines a bounded operator on by
If is trace-class, then is also trace-class with
This shows that the definition of the Fredholm determinant given by
makes sense.
Properties
If is a trace-class operator
defines an entire function such that
The function is continuous on trace-class operators, with
One can improve this inequality slightly to the following, as noted in Chapter 5 of Simon:
If and
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https://en.wikipedia.org/wiki/Attosecond%20physics
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Attosecond physics, also known as attophysics, or more generally attosecond science, is a branch of physics that deals with light-matter interaction phenomena wherein attosecond (10−18 s) photon pulses are used to unravel dynamical processes in matter with unprecedented time resolution.
Attosecond science mainly employs pump–probe spectroscopic methods to investigate the physical process of interest. Due to the complexity of this field of study, it generally requires a synergistic interplay between state-of-the-art experimental setup and advanced theoretical tools to interpret the data collected from attosecond experiments.
The main interests of attosecond physics are:
Atomic physics: investigation of electron correlation effects, photo-emission delay and ionization tunneling.
Molecular physics and molecular chemistry: role of electronic motion in molecular excited states (e.g. charge-transfer processes), light-induced photo-fragmentation, and light-induced electron transfer processes.
Solid-state physics: investigation of exciton dynamics in advanced 2D materials, petahertz charge carrier motion in solids, spin dynamics in ferromagnetic materials.
One of the primary goals of attosecond science is to provide advanced insights into the quantum dynamics of electrons in atoms, molecules and solids with the long-term challenge of achieving real-time control of the electron motion in matter.
The advent of broadband solid-state titanium-doped sapphire based (Ti:Sa) lasers (1
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https://en.wikipedia.org/wiki/QPC
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QPC may refer to:
Quantum point contact, in physics
The Quarter Pounder with Cheese, a McDonald's menu item
Queens Park Centre, in England
Queen's Privy Council for Canada
QueryPerformanceCounter, an API for the High Precision Event Timer, a hardware timer used in personal computers
Quaid e azam public college, in Gujranwala Pakistan
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https://en.wikipedia.org/wiki/Tryptone
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Tryptone is the assortment of peptides formed by the digestion of casein by the protease trypsin.
Tryptone is commonly used in microbiology to produce lysogeny broth (LB) for the growth of E. coli and other microorganisms. It provides a source of amino acids for the growing bacteria. Tryptone is similar to casamino acids, both being digests of casein, but casamino acids can be produced by acid hydrolysis and typically only have free amino acids and few peptide chains; tryptone by contrast is the product of an incomplete enzymatic hydrolysis with some oligopeptides present.
Tryptone is also a component of some germination media used in plant propagation.
See also
Albumose
Trypticase soy agar
References
Peptides
Microbiological media ingredients
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https://en.wikipedia.org/wiki/Ring%20of%20sets
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In mathematics, there are two different notions of a ring of sets, both referring to certain families of sets.
In order theory, a nonempty family of sets is called a ring (of sets) if it is closed under union and intersection. That is, the following two statements are true for all sets and ,
implies and
implies
In measure theory, a nonempty family of sets is called a ring (of sets) if it is closed under union and relative complement (set-theoretic difference). That is, the following two statements are true for all sets and ,
implies and
implies
This implies that a ring in the measure-theoretic sense always contains the empty set. Furthermore, for all sets and ,
which shows that a family of sets closed under relative complement is also closed under intersection, so that a ring in the measure-theoretic sense is also a ring in the order-theoretic sense.
Examples
If is any set, then the power set of (the family of all subsets of ) forms a ring of sets in either sense.
If is a partially ordered set, then its upper sets (the subsets of with the additional property that if belongs to an upper set U and , then must also belong to ) are closed under both intersections and unions. However, in general it will not be closed under differences of sets.
The open sets and closed sets of any topological space are closed under both unions and intersections.
On the real line , the family of sets consisting of the empty set and all finite unions of half-open intervals
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https://en.wikipedia.org/wiki/Crossing
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Crossing may refer to:
Crossing (2008 film), a South Korean film
Crossing (album), a 1985 album by world music/jazz group Oregon
Crossing (architecture), the junction of the four arms of a cruciform church
Crossing (knot theory), a visualization of intersections in mathematical knots
Crossing (physics), the relation between particle and antiparticle scattering
Crossing (plant), deliberate interbreeding of plants
Crossing oneself, a ritual hand motion made by some Christians
William Crossing (1847–1928), English writer
Intersection (road), also known as a crossing
Level crossing, a railway crossing a street
See also
Crossings (disambiguation)
The Crossing (disambiguation)
Cross (disambiguation)
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https://en.wikipedia.org/wiki/Information%20paradox
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Information paradox is the short form for two paradoxes:
Arrow information paradox in economics
Black hole information paradox in physics
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https://en.wikipedia.org/wiki/Twistor%20space
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In mathematics and theoretical physics (especially twistor theory), twistor space is the complex vector space of solutions of the twistor equation . It was described in the 1960s by Roger Penrose and Malcolm MacCallum. According to Andrew Hodges, twistor space is useful for conceptualizing the way photons travel through space, using four complex numbers. He also posits that twistor space may aid in understanding the asymmetry of the weak nuclear force.
Informal motivation
In the (translated) words of Jacques Hadamard: "the shortest path between two truths in the real domain passes through the complex domain." Therefore when studying four-dimensional space it might be valuable to identify it with However, since there is no canonical way of doing so, instead all isomorphisms respecting orientation and metric between the two are considered. It turns out that complex projective 3-space parametrizes such isomorphisms together with complex coordinates. Thus one complex coordinate describes the identification and the other two describe a point in . It turns out that vector bundles with self-dual connections on (instantons) correspond bijectively to holomorphic vector bundles on complex projective 3-space .
Formal definition
For Minkowski space, denoted , the solutions to the twistor equation are of the form
where and are two constant Weyl spinors and is a point in Minkowski space. The are the Pauli matrices, with the indexes on the matrices. This twistor space is a fo
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https://en.wikipedia.org/wiki/Sim4
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Sim4 is a nucleotide sequence alignment program akin to BLAST but specifically tailored to DNA to cDNA/EST (Expressed Sequence Tag) alignment (as opposed to DNA–DNA or protein–protein alignment). It was written by Florea et al.
External links
A Computer Program for Aligning a cDNA Sequence with a Genomic DNA Sequence
Download
Phylogenetics software
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https://en.wikipedia.org/wiki/Topological%20algebra
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In mathematics, a topological algebra is an algebra and at the same time a topological space, where the algebraic and the topological structures are coherent in a specified sense.
Definition
A topological algebra over a topological field is a topological vector space together with a bilinear multiplication
,
that turns into an algebra over and is continuous in some definite sense. Usually the continuity of the multiplication is expressed by one of the following (non-equivalent) requirements:
joint continuity: for each neighbourhood of zero there are neighbourhoods of zero and such that (in other words, this condition means that the multiplication is continuous as a map between topological spaces or
stereotype continuity: for each totally bounded set and for each neighbourhood of zero there is a neighbourhood of zero such that and , or
separate continuity: for each element and for each neighbourhood of zero there is a neighbourhood of zero such that and .
(Certainly, joint continuity implies stereotype continuity, and stereotype continuity implies separate continuity.) In the first case is called a "topological algebra with jointly continuous multiplication", and in the last, "with separately continuous multiplication".
A unital associative topological algebra is (sometimes) called a topological ring.
History
The term was coined by David van Dantzig; it appears in the title of his doctoral dissertation (1931).
Examples
1. Fréchet algebras are ex
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https://en.wikipedia.org/wiki/Chris%20Malachowsky
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Chris Malachowsky (born May 2, 1959) is an American electrical engineer, one of the co-founders of computer graphics company Nvidia.
Raised in the Oakhurst section of Ocean Township, Monmouth County, New Jersey, Malachowsky graduated from Ocean Township High School in 1976. He received a B.S. degree in 1983, in electrical engineering from the University of Florida and an M.S. degree in 1986 from Santa Clara University. In 2008, he received the Distinguished Alumni Award from Santa Clara University and received Distinguished Alumni Award from University of Florida College of Engineering in 2017.
Early in his career, he worked for Hewlett-Packard and Sun Microsystems. He co-founded Nvidia in April 1993 with Curtis Priem and Jen-Hsun Huang and is a Senior Vice President for Engineering and Operations.
References
Nvidia people
University of Florida College of Engineering alumni
Santa Clara University alumni
Living people
American technology company founders
Corporate executives
Ocean Township High School alumni
People from Ocean Township, Monmouth County, New Jersey
Engineers from New Jersey
1959 births
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https://en.wikipedia.org/wiki/Clearance
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Clearance can refer to:
Engineering
Engineering tolerance, a physical distance or space between two components
Hydraulic clearance, in hydraulic systems
Clearance in civil engineering, including:
The difference between the loading gauge and the structure gauge: the amount of space between the top of a rail car and the top of a tunnel or the bottom of a rail car and the top of rail
Air draft, applies to bridges across navigable waterways
Clearance car, a type of railroad car used to check clearances around the tracks
Ride height or ground clearance, the amount of space between the base of an automobile tire and the underside of the chassis
Finance and trade
Intellectual property
Collective rights management, the licensing of copyright and related rights
Sample clearance, legal permission to re-use a recording in another work
Other uses in finance and trade
Cheque clearing, the process of transferring value on a cheque from one bank account to another
The activity of a clearing house (finance), where a variety of financial instruments are cleared through the issuing institution
Customs clearance, in international trade, the movement of goods through customs barriers
Market clearing or equilibrium price, the price at which quantity supplied is equal to quantity demanded
Closeout (sale), in retail, the final sale of items to zero inventory
Other uses
Authorization or permission from an authority
Air traffic control clearance in aviation
Security clearance,
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https://en.wikipedia.org/wiki/Headroom
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Headroom or HeadRoom may refer to:
Vertical clearance, in engineering, the maximum distance overhead (the difference between the structure gauge and the loading gauge)
Headroom (audio signal processing), the difference between the nominal signal value and the maximum undistorted value
Headroom (photographic framing), in camera work, the space between the top of the head and the upper frame limit
Headroom (Bleu album), an album by alt-rock musician Bleu
Headroom (Don McLean album)
Head Room or Headroom, alternate name for Direct to Disc (FM album)
"Head Room", a song by 10cc from their 1976 album How Dare You!
Max Headroom (disambiguation), fictional artificial intelligence character, and associated appearances
Helix HeadRoom, DOS memory management software by Helix Software Company
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https://en.wikipedia.org/wiki/David%20G.%20Cory
|
David G. Cory is a Professor of Chemistry at the University of Waterloo where he holds the Canada Excellence Research Chair in Quantum Information Processing. He works at the Institute for Quantum Computing, and is also associated with the Waterloo Institute for Nanotechnology.
Education and career
Cory was educated at Case Western Reserve University, earning a bachelor's degree there in 1981 and a Ph.D. in chemistry in 1987. He carried out postdoctoral research at Radboud University Nijmegen in the Netherlands and at Naval Research Laboratory in Washington, D.C. He was a Professor of Nuclear Engineering at Massachusetts Institute of Technology prior to his 2010 appointment at Waterloo. At MIT, he worked on NMR, including his work on NMR quantum computation. Together with Amr Fahmy and Timothy Havel he developed the concept of pseudo-pure states and performed the first experimental demonstrations of NMR quantum computing.
Cory's research also concerns the realization and application of quantum control in various physical systems and devices. In 2015, he and teams from University of Waterloo, National Institute of Standards and Technology and Boston University demonstrated the generation and control of orbital angular momentum of neutron beams using a fork-dislocation grating, extending the existing work in optical and electron beams to neutrons. They subsequently demonstrated the control of both the spin and orbital angular momentum degrees of freedom of neutron beams.
S
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https://en.wikipedia.org/wiki/Large%20gauge%20transformation
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Given a topological space M, a topological group G and a principal G-bundle over M, a global section of that principal bundle is a gauge fixing and the process of replacing one section by another is a gauge transformation. If a gauge transformation isn't homotopic to the identity, it is called a large gauge transformation.
In theoretical physics, M often is a manifold and G is a Lie group.
See also
Large diffeomorphism
Global anomaly
Gauge theories
Anomalies (physics)
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https://en.wikipedia.org/wiki/Philosophical%20interpretation%20of%20classical%20physics
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Classical Newtonian physics has, formally, been replaced by quantum mechanics on the small scale and relativity on the large scale. Because most humans continue to think in terms of the kind of events we perceive in the human scale of daily life, it became necessary to provide a new philosophical interpretation of classical physics. Classical mechanics worked extremely well within its domain of observation but made inaccurate predictions at very small scale – atomic scale systems – and when objects moved very fast or were very massive. Viewed through the lens of quantum mechanics or relativity, we can now see that classical physics, imported from the world of our everyday experience, includes notions for which there is no actual evidence. For example, one commonly held idea is that there exists one absolute time shared by all observers. Another is the idea that electrons are discrete entities like miniature planets that circle the nucleus in definite orbits.
The correspondence principle says that classical accounts are approximations to quantum mechanics that are for all practical purposes equivalent to quantum mechanics when dealing with macro-scale events.
Various problems occur if classical mechanics is used to describe quantum systems, such as the ultraviolet catastrophe in black-body radiation, the Gibbs paradox, and the lack of a zero point for entropy.
Since classical physics corresponds more closely to ordinary language than modern physics does, this subject is als
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https://en.wikipedia.org/wiki/The%20Chemical%20History%20of%20a%20Candle
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The Chemical History of a Candle was the title of a series of six lectures on the chemistry and physics of flames given by Michael Faraday at the Royal Institution in 1848, as part of the series of Christmas lectures for young people founded by Faraday in 1825 and still given there every year.
The lectures described the different zones of combustion in the candle flame and the presence of carbon particles in the luminescent zone. Demonstrations included the production and examination of the properties of hydrogen, oxygen, nitrogen and carbon dioxide gases. An electrolysis cell is demonstrated, first in the electroplating of platinum conductors by dissolved copper, then the production of hydrogen and oxygen gases and their recombination to form water. The properties of water itself are studied, including its expansion while freezing (iron vessels are burst by this expansion), and the relative volume of steam produced when water is vaporized. Techniques for weighing gases on a balance are demonstrated. Atmospheric pressure is described and its effects demonstrated.
Faraday emphasizes that several of the demonstrations and experiments performed in the lectures may be performed by children "at home" and makes several comments regarding proper attention to safety.
The lectures were first printed as a book in 1861.
In 2016, Bill Hammack published a video series of the lectures supplemented by commentary and a companion book. Faraday's ideas are still used as the basis for open
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https://en.wikipedia.org/wiki/ESOP
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ESOP may refer to:
European Symposium on Programming, a conference in computer science
Employee stock ownership plan, an employee-owner scheme
See also
Aesop, an ancient Greek storyteller
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https://en.wikipedia.org/wiki/Static%20library
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In computer science, a static library or statically-linked library is a set of routines, external functions and variables which are resolved in a caller at compile-time and copied into a target application by a compiler, linker, or binder, producing an object file and a stand-alone executable. This executable and the process of compiling it are both known as a static build of the program. Historically, libraries could only be static. Static libraries are either merged with other static libraries and object files during building/linking to form a single executable or loaded at run-time into the address space of their corresponding executable at a static memory offset determined at compile-time/link-time.
Advantages and disadvantages
There are several advantages to statically linking libraries with an executable instead of dynamically linking them. The most significant advantage is that the application can be certain that all its libraries are present and that they are the correct version. This avoids dependency problems, known colloquially as DLL Hell or more generally dependency hell. Static linking can also allow the application to be contained in a single executable file, simplifying distribution and installation.
With static linking, it is enough to include those parts of the library that are directly and indirectly referenced by the target executable (or target library). With dynamic libraries, the entire library is loaded, as it is not known in advance which functions
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https://en.wikipedia.org/wiki/Shunting%20yard%20algorithm
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In computer science, the shunting yard algorithm is a method for parsing arithmetical or logical expressions, or a combination of both, specified in infix notation. It can produce either a postfix notation string, also known as Reverse Polish notation (RPN), or an abstract syntax tree (AST). The algorithm was invented by Edsger Dijkstra and named the "shunting yard" algorithm because its operation resembles that of a railroad shunting yard. Dijkstra first described the shunting yard algorithm in the Mathematisch Centrum report MR 34/61.
Like the evaluation of RPN, the shunting yard algorithm is stack-based. Infix expressions are the form of mathematical notation most people are used to, for instance or . For the conversion there are two text variables (strings), the input and the output. There is also a stack that holds operators not yet added to the output queue. To convert, the program reads each symbol in order and does something based on that symbol. The result for the above examples would be (in Reverse Polish notation) and , respectively.
The shunting yard algorithm will correctly parse all valid infix expressions, but does not reject all invalid expressions. For example, is not a valid infix expression, but would be parsed as . The algorithm can however reject expressions with mismatched parentheses.
The shunting yard algorithm was later generalized into operator-precedence parsing.
A simple conversion
Input:
Push 3 to the output queue (whenever a number is re
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https://en.wikipedia.org/wiki/Topological%20quantum%20number
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In physics, a topological quantum number (also called topological charge) is any quantity, in a physical theory, that takes on only one of a discrete set of values, due to topological considerations. Most commonly, topological quantum numbers are topological invariants associated with topological defects or soliton-type solutions of some set of differential equations modeling a physical system, as the solitons themselves owe their stability to topological considerations. The specific "topological considerations" are usually due to the appearance of the fundamental group or a higher-dimensional homotopy group in the description of the problem, quite often because the boundary, on which the boundary conditions are specified, has a non-trivial homotopy group that is preserved by the differential equations. The topological quantum number of a solution is sometimes called the winding number of the solution, or, more precisely, it is the degree of a continuous mapping.
Recent ideas about the nature of phase transitions indicates that topological quantum numbers, and their associated solutions, can be created or destroyed during a phase transition.
Particle physics
In particle physics, an example is given by the Skyrmion, for which the baryon number is a topological quantum number. The origin comes from the fact that the isospin is modelled by SU(2), which is isomorphic to the 3-sphere and inherits the group structure of SU(2) through its bijective association, so the isomorphis
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https://en.wikipedia.org/wiki/Pascal%20Lee
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Pascal Lee (; born 1964) is co-founder and chairman of the Mars Institute, a planetary scientist at the SETI Institute, and the Principal Investigator of the Haughton-Mars Project (HMP) at NASA Ames Research Center in Mountain View, California. He holds an ME in geology and geophysics from the University of Paris, and a PhD in astronomy and space sciences from Cornell University.
Lee's research focuses on Mars, asteroids, and impact craters, in particular in connection with the history of water on planets and the possibility of extraterrestrial life. He is known internationally for his work on Moon and Mars analogs in the Arctic, Antarctica, and other extreme environments on Earth. He is the author and co-author of over 100 scientific publications, and first proposed the "Mars Always Cold, Sometimes Wet" model of Mars evolution based on field studies of the geology of Earth's polar regions.
In 1988, Lee wintered over for 402 days at Dumont d'Urville station, Adelie Land, Antarctica, where he served as the station's chief geophysicist. He also participated in five summer campaigns in Antarctica as a geologist and planetary scientist, in particular as a member of the US Antarctic Search for Meteorites (ANSMET) program.
In 1997, Lee initiated the Haughton-Mars Project (HMP), an international multidisciplinary field research project centered on science and exploration studies at the Haughton impact crater and surrounding terrain on Devon Island, Arctic Canada, viewed as an ana
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https://en.wikipedia.org/wiki/Morse%E2%80%93Kelley%20set%20theory
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In the foundations of mathematics, Morse–Kelley set theory (MK), Kelley–Morse set theory (KM), Morse–Tarski set theory (MT), Quine–Morse set theory (QM) or the system of Quine and Morse is a first-order axiomatic set theory that is closely related to von Neumann–Bernays–Gödel set theory (NBG). While von Neumann–Bernays–Gödel set theory restricts the bound variables in the schematic formula appearing in the axiom schema of Class Comprehension to range over sets alone, Morse–Kelley set theory allows these bound variables to range over proper classes as well as sets, as first suggested by Quine in 1940 for his system ML.
Morse–Kelley set theory is named after mathematicians John L. Kelley and Anthony Morse and was first set out by and later in an appendix to Kelley's textbook General Topology (1955), a graduate level introduction to topology. Kelley said the system in his book was a variant of the systems due to Thoralf Skolem and Morse. Morse's own version appeared later in his book A Theory of Sets (1965).
While von Neumann–Bernays–Gödel set theory is a conservative extension of Zermelo–Fraenkel set theory (ZFC, the canonical set theory) in the sense that a statement in the language of ZFC is provable in NBG if and only if it is provable in ZFC, Morse–Kelley set theory is a proper extension of ZFC. Unlike von Neumann–Bernays–Gödel set theory, where the axiom schema of Class Comprehension can be replaced with finitely many of its instances, Morse–Kelley set theory cannot be
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https://en.wikipedia.org/wiki/Hafnium%20tetrachloride
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Hafnium(IV) chloride is the inorganic compound with the formula HfCl4. This colourless solid is the precursor to most hafnium organometallic compounds. It has a variety of highly specialized applications, mainly in materials science and as a catalyst.
Preparation
HfCl4 can be produced by several related procedures:
The reaction of carbon tetrachloride and hafnium oxide at above 450 °C;
HfO2 + 2 CCl4 → HfCl4 + 2 COCl2
Chlorination of a mixture of HfO2 and carbon above 600 °C using chlorine gas or sulfur monochloride:
HfO2 + 2 Cl2 + C → HfCl4 + CO2
Chlorination of hafnium carbide above 250 °C.
Separation of Zr and Hf
Hafnium and zirconium occur together in minerals such as zircon, cyrtolite and baddeleyite. Zircon contains 0.05% to 2.0% hafnium dioxide HfO2, cyrtolite with 5.5% to 17% HfO2 and baddeleyite contains 1.0 to 1.8 percent HfO2. Hafnium and zirconium compounds are extracted from ores together and converted to a mixture of the tetrachlorides.
The separation of HfCl4 and ZrCl4 is difficult because the compounds of Hf and Zr have very similar chemical and physical properties. Their atomic radii are similar: the atomic radius is 156.4 pm for hafnium, whereas that of Zr is 160 pm. These two metals undergo similar reactions and form similar coordination complexes.
A number of processes have been proposed to purify HfCl4 from ZrCl4 including fractional distillation, fractional precipitation, fractional crystallization and ion exchange. The log (base 10
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https://en.wikipedia.org/wiki/K.%20Santhanam
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Kasturiranga Santhanam (1895 – 28 February 1980), also known as Kumitithadal Santhanam, was an Indian politician. He was a conservative Iyengar from Tamil Nadu.
Early life
Santhanam obtained a Master of Arts degree in mathematics from the University of Madras (St. Joseph's College, Trichy) and later a law degree from the Law College of Madras, now known as Chennai. He joined the Indian National Congress and participated in the Indian Independence Movement at a young age and was imprisoned once for that. He was a follower of Mahatma Gandhi and his wife died while at the Gandhi Ashram, while he was in jail. From 1937 to 1942, he was a member of the Imperial Legislative Assembly, and from 1946 was a member of the Indian Constituent Assembly, from 1948 serving as Union Minister for Railways and Transport in Jawaharlal Nehru's cabinet. He stood as a Congress candidate for the House of the People from Mayuram in Tanjore district, but lost to a Communist candidate. In February 1952, he was appointed the Governor of Vindhya Pradesh.
Santhanam committee
In 1962, Lal Bahadur Sastri appointed Santhanam to preside over the committee on anti-corruption. Because of its thorough investigative work and recommendations, the Committee earned a reputation as Santhanam's Committee on Anti-Corruption. In his 1976 'Code of Conduct for persons in power, authority or positions of trust in our country', he explicitly included ministers and members of Parliament and state legislatures. There should
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https://en.wikipedia.org/wiki/Karl-Henning%20Rehren
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Karl-Henning Rehren (born 1956 in Celle) is a German physicist who focuses on algebraic quantum field theory.
Biography
Rehren studied physics in Heidelberg, Paris and Freiburg. In Freiburg he received his PhD (advisor Klaus Pohlmeyer) in 1984. Habilitation 1991 in Berlin. Since 1997 he teaches physics in Göttingen.
He became notable outside his field, especially among string theorists, in 1999 when he discovered the Algebraic holography (also called Rehren duality), a relation between quantum field theories AdSd+1 and conformal quantum field theories on d-dimensional Minkowski spacetime, which is similar in scope to the Holographic principle. This work has no direct relation to the more well known Maldacena duality, but refers to the more general statement of the AdS/CFT correspondence by Edward Witten. It is generally accepted that the relation found by Rehren does not provide a proof for Witten's conjecture and is thus considered an independent result.
Selected publications
See also
AdS/CFT correspondence
Axiomatic quantum field theory
Conformal field theory
Local quantum physics
Quantum field theory
Rehren duality
References
External links
.
.
Author page on INSPIRE-HEP
1956 births
Living people
20th-century German physicists
Heidelberg University alumni
University of Paris alumni
University of Freiburg alumni
Academic staff of the University of Göttingen
People from Celle
21st-century German physicists
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https://en.wikipedia.org/wiki/Wess%E2%80%93Zumino%20model
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In theoretical physics, the Wess–Zumino model has become the first known example of an interacting four-dimensional quantum field theory with linearly realised supersymmetry. In 1974, Julius Wess and Bruno Zumino studied, using modern terminology, dynamics of a single chiral superfield (composed of a complex scalar and a spinor fermion) whose cubic superpotential leads to a renormalizable theory.
The treatment in this article largely follows that of Figueroa-O'Farrill's lectures on supersymmetry, and to some extent of Tong.
The model is an important model in supersymmetric quantum field theory. It is arguably the simplest supersymmetric field theory in four dimensions, and is ungauged.
The Wess–Zumino action
Preliminary treatment
Spacetime and matter content
In a preliminary treatment, the theory is defined on flat spacetime (Minkowski space). For this article, the metric has mostly plus signature. The matter content is a real scalar field , a real pseudoscalar field , and a real (Majorana) spinor field .
This is a preliminary treatment in the sense that the theory is written in terms of familiar scalar and spinor fields which are functions of spacetime, without developing a theory of superspace or superfields, which appear later in the article.
Free, massless theory
The Lagrangian of the free, massless Wess–Zumino model is
where
The corresponding action is
.
Massive theory
Supersymmetry is preserved when adding a mass term of the form
Interacting theor
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https://en.wikipedia.org/wiki/Superconformal%20algebra
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In theoretical physics, the superconformal algebra is a graded Lie algebra or superalgebra that combines the conformal algebra and supersymmetry. In two dimensions, the superconformal algebra is infinite-dimensional. In higher dimensions, superconformal algebras are finite-dimensional and generate the superconformal group (in two Euclidean dimensions, the Lie superalgebra does not generate any Lie supergroup).
Superconformal algebra in dimension greater than 2
The conformal group of the -dimensional space is and its Lie algebra is . The superconformal algebra is a Lie superalgebra containing the bosonic factor and whose odd generators transform in spinor representations of . Given Kac's classification of finite-dimensional simple Lie superalgebras, this can only happen for small values of and . A (possibly incomplete) list is
in 3+0D thanks to ;
in 2+1D thanks to ;
in 4+0D thanks to ;
in 3+1D thanks to ;
in 2+2D thanks to ;
real forms of in five dimensions
in 5+1D, thanks to the fact that spinor and fundamental representations of are mapped to each other by outer automorphisms.
Superconformal algebra in 3+1D
According to the superconformal algebra with supersymmetries in 3+1 dimensions is given by the bosonic generators , , , , the U(1) R-symmetry , the SU(N) R-symmetry and the fermionic generators , , and . Here, denote spacetime indices; left-handed Weyl spinor indices; right-handed Weyl spinor indices; and the internal R-symmetry indices
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https://en.wikipedia.org/wiki/Hagedorn%20temperature
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The Hagedorn temperature, TH, is the temperature in theoretical physics where hadronic matter (i.e. ordinary matter) is no longer stable, and must either "evaporate" or convert into quark matter; as such, it can be thought of as the "boiling point" of hadronic matter. It was discovered by Rolf Hagedorn. The Hagedorn temperature exists because the amount of energy available is high enough that matter particle (quark–antiquark) pairs can be spontaneously pulled from vacuum. Thus, naively considered, a system at Hagedorn temperature can accommodate as much energy as one can put in, because the formed quarks provide new degrees of freedom, and thus the Hagedorn temperature would be an impassable absolute hot. However, if this phase is viewed as quarks instead, it becomes apparent that the matter has transformed into quark matter, which can be further heated.
The Hagedorn temperature, TH, is about or about , little above the mass–energy of the lightest hadrons, the pion. Matter at Hagedorn temperature or above will spew out fireballs of new particles, which can again produce new fireballs, and the ejected particles can then be detected by particle detectors. This quark matter has been detected in heavy-ion collisions at SPS and LHC in CERN (France and Switzerland) and at RHIC in Brookhaven National Laboratory (USA).
In string theory, a separate Hagedorn temperature can be defined for strings rather than hadrons. This temperature is extremely high (1030 K) and thus of mainly the
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https://en.wikipedia.org/wiki/Weinberg%E2%80%93Witten%20theorem
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In theoretical physics, the Weinberg–Witten (WW) theorem, proved by Steven Weinberg and Edward Witten, states that massless particles (either composite or elementary) with spin j > 1/2 cannot carry a
Lorentz-covariant current, while massless particles with spin j > 1 cannot carry a Lorentz-covariant stress-energy. The theorem is usually interpreted to mean that the graviton (j = 2) cannot be a composite particle in a relativistic quantum field theory.
Background
During the 1980s, preon theories, technicolor and the like were very popular and some people speculated that gravity might be an emergent phenomenon or that gluons might be composite. Weinberg and Witten, on the other hand, developed a no-go theorem that excludes, under very general assumptions, the hypothetical composite and emergent theories. Decades later new theories of emergent gravity are proposed and some high-energy physicists are still using this theorem to try and refute such theories. Because most of these emergent theories aren't Lorentz covariant, the WW theorem doesn't apply. The violation of Lorentz covariance, however, usually leads to other problems.
Theorem
Weinberg and Witten proved two separate results. According to them, the first is due to Sidney Coleman, who did not publish it:
A 3 + 1D QFT (quantum field theory) with a conserved 4-vector current (see four-current) which is Poincaré covariant (and gauge invariant if there happens to be any gauge symmetry which hasn't been gauge-fixed)
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https://en.wikipedia.org/wiki/Rational%20conformal%20field%20theory
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In theoretical physics, a rational conformal field theory is a special type of two-dimensional conformal field theory with a finite number of conformal primaries. In these theories, all dimensions (and the central charge) are rational numbers that can be computed from the consistency conditions of conformal field theory. The most famous examples are the so-called minimal models.
More generally, rational conformal field theory can refer to any CFT with a finite number of primary operators with respect to the action of its chiral algebra. Chiral algebras can be much larger than the Virasoro algebra. Well-known examples include (the enveloping algebra of) affine Lie algebras, relevant to the Wess–Zumino–Witten model, and W-algebras.
Conformal field theory
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https://en.wikipedia.org/wiki/Minimal%20model%20%28physics%29
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In theoretical physics, a minimal model or Virasoro minimal model is a two-dimensional conformal field theory whose spectrum is built from finitely many irreducible representations of the Virasoro algebra.
Minimal models have been classified and solved, and found to obey an ADE classification.
The term minimal model can also refer to a rational CFT based on an algebra that is larger than the Virasoro algebra, such as a W-algebra.
Relevant representations of the Virasoro algebra
Representations
In minimal models, the central charge of the Virasoro algebra takes values of the type
where are coprime integers such that .
Then the conformal dimensions of degenerate representations are
and they obey the identities
The spectrums of minimal models are made of irreducible, degenerate lowest-weight representations of the Virasoro algebra, whose conformal dimensions are of the type with
Such a representation is a coset of a Verma module by its infinitely many nontrivial submodules. It is unitary if and only if . At a given central charge, there are distinct representations of this type. The set of these representations, or of their conformal dimensions, is called the Kac table with parameters . The Kac table is usually drawn as a rectangle of size , where each representation appears twice
due to the relation
Fusion rules
The fusion rules of the multiply degenerate representations encode constraints from all their null vectors. They can therefore be deduced from the fusio
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https://en.wikipedia.org/wiki/158%20%28number%29
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158 (one hundred [and] fifty-eight) is the natural number following 157 and preceding 159.
In mathematics
158 is a nontotient, since there is no integer with 158 coprimes below it. 158 is a Perrin number, appearing after 68, 90, 119.
158 is the number of digits in the decimal expansion of 100!, the product of all the natural numbers up to and including 100.
In the military
was a United States Navy during World War II
was a United States Navy during World War II
was a United States Navy during World War II
was a United States Navy following World War II
was a United States Navy during World War II
was a United States Navy Trefoil-class concrete barge during World War II
was a United States Navy during World War II
was a United States Navy converted yacht patrol vessel during World War I
In music
The song 158 by the Indie-rock band Blackbud
The song "Here We Go" (1998) from The Bouncing Souls’ Tie One On CD includes the lyrics "Me, Shal Pete and Lamar thumbed down the ramp of Exit 158"
In transportation
The Alfa Romeo 158 racecar
The Ferrari 158 racecar produced between 1964 and 1965
The British Rail Class 158 Express Sprinter is a diesel multiple unit (DMU) train, built for British Rail between 1989 and 1992
In other fields
158 is also:
The year AD 158 or 158 BC
One of a number of highways
The atomic number of an element temporarily called unpentoctium.
158 Koronis is a Main belt asteroid
In the Israeli satirical comedy Operation Grandma (
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https://en.wikipedia.org/wiki/Index%20of%20electrical%20engineering%20articles
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This is an alphabetical list of articles pertaining specifically to electrical and electronics engineering. For a thematic list, please see List of electrical engineering topics. For a broad overview of engineering, see List of engineering topics. For biographies, see List of engineers.
#
866A –
15 kV AC –
2D computer graphics –
3Com –
A
Abrasion (mechanical) –
AC adapter –
AC power plugs and sockets –
AC power –
AC/AC converter –
AC/DC receiver design –
AC/DC conversion –
Active rectification –
Actuator –
Adaptive control –
Adjustable-speed drive –
Advanced Z-transform –
Affinity law –
Agbioeletric –
AIEE –
All American Five –
Alloy –
ALOHAnet –
Alpha–beta transformation –
Altair 8800 –
Alternating current –
Alternator (auto) –
Alternator synchronization--
Alternator –
Altitude –
Aluminium smelting –
AIEE –
Ammeter –
Amorphous metal transformer –
Ampacity –
Ampere –
Ampère's circuital law –
Ampère's force law –
Ampère's law –
Amplidyne –
Amplifier –
Amplitude modulation –
Analog circuit –
Analog filter –
Analog signal processing –
Analog signal –
Analog-to-digital converter –
Annealing (metallurgy) –
Anode –
Antenna (radio) –
Apollo program –
Apparent power –
Apple Computer –
Arc converter –
Arc furnace –
Arc lamp –
Arc welder –
Argon –
Arithmetic mean –
Armature (electrical engineering) –
Artificial heart –
Artificial intelligence –
Artificial neural networks –
Artificial pacemaker –
ASTM –
Asymptotic s
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https://en.wikipedia.org/wiki/Anthony%20G.%20Collins
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Anthony G. Collins (born 1949) was the 16th President of Clarkson University in Potsdam, New York.
Early life, education, and career
Collins grew up outside Melbourne, Australia. He earned an undergraduate civil engineering degree from Monash University, and his master's and Ph.D degrees from Lehigh University in Pennsylvania. Prior to his doctoral studies, he worked for Australian Consolidated Industries and Utah Development Company.
Career at Clarkson
After receiving his Ph.D. in 1982, Collins began his academic career as an assistant professor of civil and environmental engineering at Clarkson. He eventually rose to the rank of professor, and served many administrative roles, including department chair, dean, vice president for academic affairs, and provost. He was elected the 16th president of Clarkson University in 2003.
At Clarkson, He received the John W. Graham Faculty Research Award, the Distinguished Teaching Award, and two Outstanding Advising awards. In February 2007, Collins was recognized by Lehigh University for his accomplishments in advancing engineering education and as a leader in higher education, when he received the Lynn S. Beedle Award.
Collins is a regional and national advocate for higher education-industrial partnerships that couple research discovery and engineering innovation with enterprise for commercialization and economic development with a focus on advancing sustainable energy solutions and environmental technology innovation. New York S
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https://en.wikipedia.org/wiki/Substring
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In formal language theory and computer science, a substring is a contiguous sequence of characters within a string. For instance, "the best of" is a substring of "It was the best of times". In contrast, "Itwastimes" is a subsequence of "It was the best of times", but not a substring.
Prefixes and suffixes are special cases of substrings. A prefix of a string is a substring of that occurs at the beginning of ; likewise, a suffix of a string is a substring that occurs at the end of .
The substrings of the string "apple" would be:
"a", "ap", "app", "appl", "apple",
"p", "pp", "ppl", "pple",
"pl", "ple",
"l", "le"
"e", ""
(note the empty string at the end).
Substring
A string is a substring (or factor) of a string if there exists two strings and such that . In particular, the empty string is a substring of every string.
Example: The string ana is equal to substrings (and subsequences) of banana at two different offsets:
banana
|||||
ana||
|||
ana
The first occurrence is obtained with b and na, while the second occurrence is obtained with ban and being the empty string.
A substring of a string is a prefix of a suffix of the string, and equivalently a suffix of a prefix; for example, nan is a prefix of nana, which is in turn a suffix of banana. If is a substring of , it is also a subsequence, which is a more general concept. The occurrences of a given pattern in a given string can be found with a string searching algorithm. Finding the longest strin
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https://en.wikipedia.org/wiki/Milnor%20map
|
In mathematics, Milnor maps are named in honor of John Milnor, who introduced them to topology and algebraic geometry in his book Singular Points of Complex Hypersurfaces (Princeton University Press, 1968) and earlier lectures. The most studied Milnor maps are actually fibrations, and the phrase Milnor fibration is more commonly encountered in the mathematical literature. These were introduced to study isolated singularities by constructing numerical invariants related to the topology of a smooth deformation of the singular space.
Definition
Let be a non-constant polynomial function of complex variables where the vanishing locus of
is only at the origin, meaning the associated variety is not smooth at the origin. Then, for (a sphere inside of radius ) the Milnor fibrationpg 68 associated to is defined as the map
,
which is a locally trivial smooth fibration for sufficiently small . Originally this was proven as a theorem by Milnor, but was later taken as the definition of a Milnor fibration. Note this is a well defined map since
,
where is the argument of a complex number.
Historical motivation
One of the original motivations for studying such maps was in the study of knots constructed by taking an -ball around a singular point of a plane curve, which is isomorphic to a real 4-dimensional ball, and looking at the knot inside the boundary, which is a 1-manifold inside of a 3-sphere. Since this concept could be generalized to hypersurfaces with isolated singulariti
|
https://en.wikipedia.org/wiki/Philip%20Ball
|
Philip Ball (born 1962) is a British science writer. For over twenty years he has been an editor of the journal Nature, for which he continues to write regularly.
He is a regular contributor to Prospect magazine and a columnist for Chemistry World, Nature Materials, and BBC Future.
He has contributed to publications ranging from New Scientist to the New York Times, The Guardian, the Financial Times, and New Statesman.
He has broadcast on many occasions on radio and TV, and in June 2004 presented a three-part serial on nanotechnology, Small Worlds, on BBC Radio 4.
Life
Ball holds a degree in chemistry from Oxford and a doctorate in physics from Bristol University.
As of 2008 he lives in London.
Work
Ball's 2004 book Critical Mass: How One Thing Leads to Another won the 2005 Aventis Prize for Science Books. It examines a wide range of topics including the business cycle, random walks, phase transitions, bifurcation theory, traffic flow, Zipf's law, Small world phenomenon, catastrophe theory, the Prisoner's dilemma. The overall theme is one of applying modern mathematical models to social and economic phenomena.
In 2011, Ball published The Music Instinct in which he discusses how we make sense of sound and Music and emotion. He outlines what is known and still unknown about how music has such an emotional impact, and why it seems indispensable to humanity. He has since argued that music is emotively powerful due to its ability to mimic humans and through setting up
|
https://en.wikipedia.org/wiki/Harry%20Huskey
|
Harry Douglas Huskey (January 19, 1916 – April 9, 2017) was an American computer design pioneer.
Early life and career
Huskey was born in Whittier, in the Smoky Mountains region of North Carolina and grew up in Idaho. He received his bachelor's degree in mathematics and physics at the University of Idaho. He was the first member of his family to attend college. He gained his Master's and then his PhD in 1943 from the Ohio State University on Contributions to the Problem of Geöcze. Huskey taught mathematics to U.S. Navy students at the University of Pennsylvania and then worked part-time on the early ENIAC and EDVAC computers in 1945. This work represented his first formal introduction to computers, according to his obituary in The New York Times.
He visited the National Physical Laboratory (NPL) in the United Kingdom for a year and worked on the Pilot ACE computer with Alan Turing and others. He was also involved with the EDVAC and SEAC computer projects.
Huskey designed and managed the construction of the Standards Western Automatic Computer (SWAC) at the National Bureau of Standards in Los Angeles (1949–1953). He also designed the G-15 computer for Bendix Aviation Corporation, a machine, operable by one person. He had one at his home that is now in the Smithsonian Institution in Washington, D.C.
After five years at the National Bureau of Standards, Huskey joined the faculty of the University of California, Berkeley in 1954 and then University of California, Santa C
|
https://en.wikipedia.org/wiki/John%20David%20Jackson%20%28physicist%29
|
John David Jackson (January 19, 1925 – May 20, 2016) was a Canadian–American physics professor at the University of California, Berkeley and a faculty senior scientist emeritus at Lawrence Berkeley National Laboratory.
A theoretical physicist, he was a member of the National Academy of Sciences, well known for his work in nuclear and particle physics, as well as his widely used graduate text on classical electrodynamics.
Education
Born in London, Ontario, Canada, Jackson attended the University of Western Ontario, receiving a B.Sc. in honors physics and mathematics in 1946. He went on to graduate study at MIT, where he worked under Victor Weisskopf, completing his Ph.D. thesis in 1949.
Academic career
Jackson held academic appointments successively at McGill University, thanks to Philip Russell Wallace, a prominent Canadian theoretical physicist, (January 1950 – 1957); then the University of Illinois at Urbana–Champaign (1957–1967); and finally the University of California, Berkeley (1967–1995). At McGill, he was Assistant and Associate Professor of Mathematics; at Illinois and Berkeley, he was in the Physics Departments. At the latter, he held appointments on campus and at the Lawrence Berkeley National Laboratory. After retiring from teaching in 1993, he continued to be active at LBNL.
McGill and Princeton
At McGill in the 1950s, in addition to appreciable teaching, Jackson found time for research on atomic processes and nuclear reactions at intermediate energies and th
|
https://en.wikipedia.org/wiki/Daniel%20Kevles
|
Daniel J. Kevles (born 2 March 1939 in Philadelphia, Pennsylvania) is an American historian of science best known for his books on American physics and eugenics and for a wide-ranging body of scholarship on science and technology in modern societies. He is Stanley Woodward Professor of History, Emeritus at Yale University and J. O. and Juliette Koepfli Professor of the Humanities, Emeritus at the California Institute of Technology.
Biography
Kevles received his BA in physics from Princeton University in 1960 and his PhD in history from Princeton in 1964. He taught at the California Institute of Technology from 1964 to 2001 and Yale University from 2001 to 2015. Since 2015, he has held additional appointments at Columbia University and New York University.
In 2001 Kevles received the George Sarton Medal of the History of Science Society, awarded for "a lifetime of scholarly achievement". In 1999 his book The Baltimore Case was awarded the Watson Davis and Helen Miles Davis Prize for best book in the history of science directed to a wide public. Kevles is a Fellow of the American Association for the Advancement of Science and the American Academy of Arts and Sciences and a member of the American Philosophical Society and the Society of American Historians.
In 2000 the mathematician Serge Lang waged an unsuccessful campaign to prevent Kevles from being granted tenure at Yale, asserting that Kevles' book The Baltimore Case was too sympathetic to David Baltimore. Although crit
|
https://en.wikipedia.org/wiki/William%20Wallace%20Smith%20Bliss
|
William Wallace Smith Bliss (August 17, 1815 – August 5, 1853) was a United States Army officer and mathematics professor. A gifted mathematician, he taught at West Point and also served as a line officer.
In December 1848 Bliss married Mary Elizabeth Taylor, youngest daughter of President-elect Zachary Taylor, whom he would serve as presidential secretary. Five years later Bliss contracted yellow fever in New Orleans and died at the age of 37.
Having become interested in the various Native American tribes, Bliss learned a number of their languages and studied their cultures. He was a member of the Royal Society of Northern Antiquaries of Copenhagen, Denmark, and an Honorary Member of the American Ethnological Society. Gifted at languages, he was able to read thirteen and could speak a number of those fluently.
Early life and education
Born in Whitehall, New York, he was the son of Captain John Bliss (of Lebanon, New Hampshire) and Olive Hall Simonds (of Todd County, Kentucky).
Military career
At the age of 14, Bliss entered the United States Military Academy on September 1, 1829. He showed very great skills in mathematics while a student. He graduated July 1, 1833 (age 17) and commissioned as a second lieutenant in the 4th Infantry Regiment. It was his choice to serve in the infantry.
He served in the Fort Mitchell army garrison in Alabama from 1833 to 1834. During 1835 he was involved in operations against the Cherokee during Indian Removal, which moved most of them to
|
https://en.wikipedia.org/wiki/Sterling%20Hall%20bombing
|
The Sterling Hall bombing occurred on the University of Wisconsin–Madison campus on August 24, 1970, and was committed by four men as an action against the university's research connections with the U.S. military during the Vietnam War. It resulted in the death of a university physics researcher and injuries to three others.
Overview
Sterling Hall is a centrally located building on the University of Wisconsin–Madison campus. The bomb, set off at 3:42 am on August 24, 1970, was intended to destroy the Army Mathematics Research Center (AMRC) housed on the 2nd, 3rd, and 4th floors of the building. It caused massive destruction to other parts of the building and nearby buildings as well. It resulted in the death of the researcher Robert Fassnacht, injured three others and caused significant destruction to the physics department and its equipment. Neither Fassnacht nor the physics department itself was involved with or employed by the Army Mathematics Research Center.
The bombers used a Ford Econoline van stolen from a University of Wisconsin professor of Computer Sciences. It was filled with close to of ANFO (i.e., ammonium nitrate and fuel oil). Pieces of the van were found on top of an eight-story building three blocks away and 26 nearby buildings were damaged; however, the targeted AMRC was scarcely damaged. Total damage to University of Wisconsin–Madison property was over $2.1 million ($ in ) as a result of the bombing.
Army Mathematics Research Center
During the Vietn
|
https://en.wikipedia.org/wiki/Shortest%20common%20supersequence
|
In computer science, the shortest common supersequence of two sequences X and Y is the shortest sequence which has X and Y as subsequences. This is a problem closely related to the longest common subsequence problem. Given two sequences X = < x1,...,xm > and Y = < y1,...,yn >, a sequence U = < u1,...,uk > is a common supersequence of X and Y if items can be removed from U to produce X and Y.
A shortest common supersequence (SCS) is a common supersequence of minimal length. In the shortest common supersequence problem, two sequences X and Y are given, and the task is to find a shortest possible common supersequence of these sequences. In general, an SCS is not unique.
For two input sequences, an SCS can be formed from a longest common subsequence (LCS) easily. For example, the longest common subsequence of X and Y is Z. By inserting the non-LCS symbols into Z while preserving their original order, we obtain a shortest common supersequence U. In particular, the equation holds for any two input sequences.
There is no similar relationship between shortest common supersequences and longest common subsequences of three or more input sequences. (In particular, LCS and SCS are not dual problems.) However, both problems can be solved in time using dynamic programming, where is the number of sequences, and is their maximum length. For the general case of an arbitrary number of input sequences, the problem is NP-hard.
Shortest common superstring
The closely related pro
|
https://en.wikipedia.org/wiki/Calvin%20Gotlieb
|
Calvin Carl "Kelly" Gotlieb, (March 27, 1921 – October 16, 2016) was a Canadian professor and computer scientist who has been called the "Father of Computing" in Canada. He was a Professor in Computer Science at the University of Toronto.
Biography
He received a Bachelor of Science in physics in 1942, a Master of Arts in 1944 and a Ph.D. in 1947 from the University of Toronto.
In 1948, he co-founded the computation centre at the University of Toronto and was part of the first team in Canada to build computers and to provide computing services. In 1950, he created the first university course on computing in Canada and in 1951 offered the first graduate course. In 1964, he helped to found the first Canadian graduate department of computer science at the University of Toronto.
In 1958, he helped to found the Canadian Information Processing Society and was its president from 1960 to 1961.
In 1995, he was made a Member of the Order of Canada. He was a Fellow of the Royal Society of Canada and in 2006, a founding Fellow of the Canadian Information Processing Society. In 1994, he received the International Federation for Information Processing Isaac L. Auerbach Award and was inducted as a Fellow of the Association for Computing Machinery.
He was married to Phyllis Bloom, a Canadian science fiction novelist and poet, from 1949 until her death in 2009. Kelly and Phyllis Gotlieb had three children: son Leo Gotlieb; daughters Margaret Gotlieb and Jane Lipson.
Kelly Gotlieb died
|
https://en.wikipedia.org/wiki/Bachelor%20of%20Computer%20Science
|
The Bachelor of Computer Science (abbreviated BCompSc or BCS) is a bachelor's degree for completion of an undergraduate program in computer science. In general, computer science degree programs emphasize the mathematical and theoretical foundations of computing.
Typical requirements
Because computer science is a wide field, courses required to earn a bachelor of computer science degree vary. A typical list of course requirements includes topics such as:
Computer programming
Programming paradigms
Algorithms
Data structures
Logic & Computation
Computer architecture
Some schools may place more emphasis on mathematics and require additional courses such as:
Linear algebra
Calculus
Probability theory and statistics
Combinatorics and discrete mathematics
Differential calculus and mathematics
Beyond the basic set of computer science courses, students can typically choose additional courses from a variety of different fields, such as:
Theory of computation
Operating systems
Numerical computation
Compilers, compiler design
Real-time computing
Distributed systems
Computer networking
Data communication
Computer graphics
Artificial intelligence
Human-computer interaction
Information theory
Software testing
Information assurance
Some schools allow students to specialize in a certain area of computer science.
Related degrees
Bachelor of Software Engineering
Bachelor of Science in Information Technology
Bachelor of Computing
Bachelor of Information Tech
|
https://en.wikipedia.org/wiki/Aptera
|
Aptera may refer to:
Biology
Aptera (cockroach), a genus of cockroaches in the family Blaberidae
Apteromantis aptera, a species of praying mantis, endemic to the Iberian Peninsula
Hopea aptera, a species of plant in the family Dipterocarpaceae, endemic to Papua New Guinea
Inga aptera, a species of legume in the family Fabaceae, found only in Brazil
Parashorea aptera, a species of plant in the family Dipterocarpaceae, endemic to Indonesia
Other uses
Aptera (Greece), the city in Crete
Aptera (Lycia), an ancient city in Lycia, now Turkey
Aptera Motors, an American high-efficiency vehicle company
Aptera 2 Series, a series of three wheelers from Aptera Motors announced in 2008
Aptera (solar electric vehicle), a solar powered three wheeler from Aptera Motors announced in 2019
See also
Aptera in the 10th edition of Systema Naturae
Apterygota, a subclass of small, wingless insects
|
https://en.wikipedia.org/wiki/Stefan%20Lucks
|
Stefan Lucks is a researcher in the fields of communications security and cryptography. Lucks is known for his attack on Triple DES, and for extending Lars Knudsen's Square attack to Twofish, a cipher outside the Square family, thus generalising the attack into integral cryptanalysis. He has also co-authored attacks on AES, LEVIATHAN, and the E0 cipher used in Bluetooth devices, as well as publishing strong password-based key agreement schemes.
Lucks graduated from the University of Dortmund in 1992, and received his PhD at the University of Göttingen in 1997.
After leaving the University of Mannheim Lucks now heads the Chair of Media Security at Bauhaus University, Weimar.
Together with Niels Ferguson, Bruce Schneier and others he developed the Skein hash function as a candidate for the NIST hash function competition.
External links
Chair of Media Security (Bauhaus-University Weimar)
Home Page (Bauhaus-University Weimar)
1965 births
Living people
Modern cryptographers
German cryptographers
Technical University of Dortmund alumni
University of Göttingen alumni
Academic staff of the University of Mannheim
Academic staff of Bauhaus University, Weimar
|
https://en.wikipedia.org/wiki/Composition%20operator
|
In mathematics, the composition operator with symbol is a linear operator defined by the rule
where denotes function composition.
The study of composition operators is covered by AMS category 47B33.
In physics
In physics, and especially the area of dynamical systems, the composition operator is usually referred to as the Koopman operator (and its wild surge in popularity is sometimes jokingly called "Koopmania"), named after Bernard Koopman. It is the left-adjoint of the transfer operator of Frobenius–Perron.
In Borel functional calculus
Using the language of category theory, the composition operator is a pull-back on the space of measurable functions; it is adjoint to the transfer operator in the same way that the pull-back is adjoint to the push-forward; the composition operator is the inverse image functor.
Since the domain considered here is that of Borel functions, the above describes the Koopman operator as it appears in Borel functional calculus.
In holomorphic functional calculus
The domain of a composition operator can be taken more narrowly, as some Banach space, often consisting of holomorphic functions: for example, some Hardy space or Bergman space. In this case, the composition operator lies in the realm of some functional calculus, such as the holomorphic functional calculus.
Interesting questions posed in the study of composition operators often relate to how the spectral properties of the operator depend on the function space. Other questions inclu
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https://en.wikipedia.org/wiki/Nuclear%20operators%20between%20Banach%20spaces
|
In mathematics, nuclear operators between Banach spaces are a linear operators between Banach spaces in infinite dimensions that share some of the properties of their counter-part in finite dimension. In Hilbert spaces such operators are usually called trace class operators and one can define such things as the trace. In Banach spaces this is no longer possible for general nuclear operators, it is however possible for -nuclear operator via the Grothendieck trace theorem.
The general definition for Banach spaces was given by Grothendieck. This article presents both cases but concentrates on the general case of nuclear operators on Banach spaces.
Nuclear operators on Hilbert spaces
An operator on a Hilbert space
is compact if it can be written in the form
where and and are (not necessarily complete) orthonormal sets. Here is a set of real numbers, the set of singular values of the operator, obeying if
The bracket is the scalar product on the Hilbert space; the sum on the right hand side must converge in norm.
An operator that is compact as defined above is said to be or if
Properties
A nuclear operator on a Hilbert space has the important property that a trace operation may be defined. Given an orthonormal basis for the Hilbert space, the trace is defined as
Obviously, the sum converges absolutely, and it can be proven that the result is independent of the basis. It can be shown that this trace is identical to the sum of the eigenvalues of (counted wi
|
https://en.wikipedia.org/wiki/Friedrich%20L.%20Bauer
|
Friedrich Ludwig "Fritz" Bauer (10 June 1924 – 26 March 2015) was a German pioneer of computer science and professor at the Technical University of Munich. He coined the term Software engineering
Life
Bauer earned his Abitur in 1942 and served in the Wehrmacht during World War II, from 1943 to 1945. From 1946 to 1950, he studied mathematics and theoretical physics at Ludwig-Maximilians-Universität in Munich. Bauer received his Doctor of Philosophy (Ph.D.) under the supervision of Fritz Bopp for his thesis Gruppentheoretische Untersuchungen zur Theorie der Spinwellengleichungen ("Group-theoretic investigations of the theory of spin wave equations") in 1952. He completed his habilitation thesis Über quadratisch konvergente Iterationsverfahren zur Lösung von algebraischen Gleichungen und Eigenwertproblemen ("On quadratically convergent iteration methods for solving algebraic equations and eigenvalue problems") in 1954 at the Technical University of Munich. After teaching as a privatdozent at the Ludwig Maximilian University of Munich from 1954 to 1958, he became extraordinary professor for applied mathematics at the University of Mainz. Since 1963, he worked as a professor of mathematics and (since 1972) computer science at the Technical University of Munich. He retired in 1989.
Work
Bauer's early work involved constructing computing machinery (e.g. the logical relay computer STANISLAUS from 1951–1955). In this context, he was the first to propose the widely used stack meth
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https://en.wikipedia.org/wiki/Fredholm%20kernel
|
In mathematics, a Fredholm kernel is a certain type of a kernel on a Banach space, associated with nuclear operators on the Banach space. They are an abstraction of the idea of the Fredholm integral equation and the Fredholm operator, and are one of the objects of study in Fredholm theory. Fredholm kernels are named in honour of Erik Ivar Fredholm. Much of the abstract theory of Fredholm kernels was developed by Alexander Grothendieck and published in 1955.
Definition
Let B be an arbitrary Banach space, and let B* be its dual, that is, the space of bounded linear functionals on B. The tensor product has a completion under the norm
where the infimum is taken over all finite representations
The completion, under this norm, is often denoted as
and is called the projective topological tensor product. The elements of this space are called Fredholm kernels.
Properties
Every Fredholm kernel has a representation in the form
with and such that and
Associated with each such kernel is a linear operator
which has the canonical representation
Associated with every Fredholm kernel is a trace, defined as
p-summable kernels
A Fredholm kernel is said to be p-summable if
A Fredholm kernel is said to be of order q if q is the infimum of all for all p for which it is p-summable.
Nuclear operators on Banach spaces
An operator : is said to be a nuclear operator if there exists an
∈ such that = . Such an operator is said to be -summable and of order if is. In general,
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https://en.wikipedia.org/wiki/Nuclear%20space
|
In mathematics, nuclear spaces are topological vector spaces that can be viewed as a generalization of finite dimensional Euclidean spaces and share many of their desirable properties. Nuclear spaces are however quite different from Hilbert spaces, another generalization of finite dimensional Euclidean spaces. They were introduced by Alexander Grothendieck.
The topology on nuclear spaces can be defined by a family of seminorms whose unit balls decrease rapidly in size. Vector spaces whose elements are "smooth" in some sense tend to be nuclear spaces; a typical example of a nuclear space is the set of smooth functions on a compact manifold. All finite-dimensional vector spaces are nuclear. There are no Banach spaces that are nuclear, except for the finite-dimensional ones. In practice a sort of converse to this is often true: if a "naturally occurring" topological vector space is a Banach space, then there is a good chance that it is nuclear.
Original motivation: The Schwartz kernel theorem
Much of the theory of nuclear spaces was developed by Alexander Grothendieck while investigating the Schwartz kernel theorem and published in . We now describe this motivation.
For any open subsets and the canonical map is an isomorphism of TVSs (where has the topology of uniform convergence on bounded subsets) and furthermore, both of these spaces are canonically TVS-isomorphic to (where since is nuclear, this tensor product is simultaneously the injective tensor product and p
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https://en.wikipedia.org/wiki/Topological%20tensor%20product
|
In mathematics, there are usually many different ways to construct a topological tensor product of two topological vector spaces. For Hilbert spaces or nuclear spaces there is a simple well-behaved theory of tensor products (see Tensor product of Hilbert spaces), but for general Banach spaces or locally convex topological vector spaces the theory is notoriously subtle.
Motivation
One of the original motivations for topological tensor products is the fact that tensor products of the spaces of smooth functions on do not behave as expected. There is an injection
but this is not an isomorphism. For example, the function cannot be expressed as a finite linear combination of smooth functions in We only get an isomorphism after constructing the topological tensor product; i.e.,
This article first details the construction in the Banach space case. is not a Banach space and further cases are discussed at the end.
Tensor products of Hilbert spaces
The algebraic tensor product of two Hilbert spaces A and B has a natural positive definite sesquilinear form (scalar product) induced by the sesquilinear forms of A and B. So in particular it has a natural positive definite quadratic form, and the corresponding completion is a Hilbert space A ⊗ B, called the (Hilbert space) tensor product of A and B.
If the vectors ai and bj run through orthonormal bases of A and B, then the vectors ai⊗bj form an orthonormal basis of A ⊗ B.
Cross norms and tensor products of Banach spaces
We sh
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https://en.wikipedia.org/wiki/Bruce%20Jay%20Nelson
|
Bruce Jay Nelson (January 19, 1952 – September 19, 1999) was an American computer scientist best known as the inventor of the remote procedure call concept for computer network communications.
Bruce Nelson graduated from Harvey Mudd College in 1974, and went on to earn a master's in computer science from Stanford University in 1976, and a Ph.D. in computer science from Carnegie Mellon University in 1982. While pursuing his Ph.D., he worked at Xerox PARC where he developed the concept of remote procedure call (RPC).
He and his collaborator Andrew Birrell were awarded the 1994 Association for Computing Machinery (ACM) Software System Award for the work on RPC.
In 1996 he joined Cisco Systems as Chief Science Officer.
He died September 19, 1999, due to complications from an aortic dissection, while on a business trip to Tel Aviv, Israel.
In 2007 the Birrell and Nelson paper won an operating system hall of fame award from the ACM. Classmates and friends endowed a scholarship in his name at Carnegie Mellon.
Harvey Mudd College also named a speaker series in his honor.
He was an avid photographer, backpacker, free-diver and world traveler.
His outgoing and eccentric personality included a fascination with crows, leading a friend to name his company "Caw Networks".
Published papers
References
1952 births
1999 deaths
Harvey Mudd College alumni
Carnegie Mellon University alumni
Deaths from aortic dissection
American computer scientists
Place of birth missing
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https://en.wikipedia.org/wiki/Functional%20determinant
|
In functional analysis, a branch of mathematics, it is sometimes possible to generalize the notion of the determinant of a square matrix of finite order (representing a linear transformation from a finite-dimensional vector space to itself) to the infinite-dimensional case of a linear operator S mapping a function space V to itself. The corresponding quantity det(S) is called the functional determinant of S.
There are several formulas for the functional determinant. They are all based on the fact that the determinant of a finite matrix is equal to the product of the eigenvalues of the matrix. A mathematically rigorous definition is via the zeta function of the operator,
where tr stands for the functional trace: the determinant is then defined by
where the zeta function in the point s = 0 is defined by analytic continuation. Another possible generalization, often used by physicists when using the Feynman path integral formalism in quantum field theory (QFT), uses a functional integration:
This path integral is only well defined up to some divergent multiplicative constant. To give it a rigorous meaning it must be divided by another functional determinant, thus effectively cancelling the problematic 'constants'.
These are now, ostensibly, two different definitions for the functional determinant, one coming from quantum field theory and one coming from spectral theory. Each involves some kind of regularization: in the definition popular in physics, two determinants can onl
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https://en.wikipedia.org/wiki/Fujikawa%20method
|
In physics, Fujikawa's method is a way of deriving the chiral anomaly in quantum field theory. It uses the correspondence between functional determinants and the partition function, effectively making use of the Atiyah–Singer index theorem.
Derivation
Suppose given a Dirac field which transforms according to a representation of the compact Lie group G; and we have a background connection form of taking values in the Lie algebra The Dirac operator (in Feynman slash notation) is
and the fermionic action is given by
The partition function is
The axial symmetry transformation goes as
Classically, this implies that the chiral current, is conserved, .
Quantum mechanically, the chiral current is not conserved: Jackiw discovered this due to the non-vanishing of a triangle diagram. Fujikawa reinterpreted this as a change in the partition function measure under a chiral transformation. To calculate a change in the measure under a chiral transformation, first consider the Dirac fermions in a basis of eigenvectors of the Dirac operator:
where are Grassmann valued coefficients, and are eigenvectors of the Dirac operator:
The eigenfunctions are taken to be orthonormal with respect to integration in d-dimensional space,
The measure of the path integral is then defined to be:
Under an infinitesimal chiral transformation, write
The Jacobian of the transformation can now be calculated, using the orthonormality of the eigenvectors
The transformation of the coefficients ar
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