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https://en.wikipedia.org/wiki/Maris%E2%80%93McGwire%E2%80%93Sosa%20pair
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In recreational mathematics, Maris–McGwire–Sosa pairs (MMS pairs, also MMS numbers) are two consecutive natural numbers such that adding each number's digits (in base 10) to the digits of its prime factorization gives the same sum.
Thus 61 → 6 + 1 (the sum of its digits) + 6 + 1 (since 61 is its prime factorization)
and 62 → 6 + 2 (the sum of its digits) + 3 + 1 + 2 (since 31 × 2 is its prime factorization).
The above two sums are equal (= 14), so 61 and 62 form an MMS pair.
MMS pairs are so named because in 1998 the baseball players Mark McGwire and Sammy Sosa both hit their 62nd home runs for the season, passing the old record of 61, held by Roger Maris. American engineer Mike Keith noticed this property of these numbers and named pairs of numbers like these MMS pairs.
See also
Ruth–Aaron pair
References
External links
Mike Keith. Maris–McGwire–Sosa Numbers.
Ivars Peterson. MathTrek – Home Run Numbers.
Hans Havermann. Maris–McGwire–Sosa 7-tuples, 8-tuples, & 9-tuples
Base-dependent integer sequences
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https://en.wikipedia.org/wiki/Burgess%20reagent
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The Burgess reagent (methyl N-(triethylammoniumsulfonyl)carbamate) is a mild and selective dehydrating reagent often used in organic chemistry. It was developed in the laboratory of Edward M. Burgess at Georgia Tech.
The Burgess reagent is used to convert secondary and tertiary alcohols with an adjacent proton into alkenes. Dehydration of primary alcohols does not work well. The reagent is soluble in common organic solvents and alcohol dehydration takes place with syn elimination through an intramolecular elimination reaction. The Burgess reagent is a carbamate and an inner salt. A general mechanism is shown below.
Preparation
The reagent is prepared from chlorosulfonylisocyanate by reaction with methanol and triethylamine in benzene:
References
Reagents for organic chemistry
Quaternary ammonium compounds
Carbamates
Zwitterions
Dehydrating agents
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https://en.wikipedia.org/wiki/Gershgorin%20circle%20theorem
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In mathematics, the Gershgorin circle theorem may be used to bound the spectrum of a square matrix. It was first published by the Soviet mathematician Semyon Aronovich Gershgorin in 1931. Gershgorin's name has been transliterated in several different ways, including Geršgorin, Gerschgorin, Gershgorin, Hershhorn, and Hirschhorn.
Statement and proof
Let be a complex matrix, with entries . For let be the sum of the absolute values of the non-diagonal entries in the -th row:
Let be a closed disc centered at with radius . Such a disc is called a Gershgorin disc.
Theorem. Every eigenvalue of lies within at least one of the Gershgorin discs
Proof. Let be an eigenvalue of with corresponding eigenvector . Find i such that the element of x with the largest absolute value is . Since , in particular we take the ith component of that equation to get:
Taking to the other side:
Therefore, applying the triangle inequality and recalling that based on how we picked i,
Corollary. The eigenvalues of A must also lie within the Gershgorin discs Cj corresponding to the columns of A.
Proof. Apply the Theorem to AT while recognizing that the eigenvalues of the transpose are the same as those of the original matrix.
Example. For a diagonal matrix, the Gershgorin discs coincide with the spectrum. Conversely, if the Gershgorin discs coincide with the spectrum, the matrix is diagonal.
Discussion
One way to interpret this theorem is that if the off-diagonal entries of a
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https://en.wikipedia.org/wiki/Canonical%20transformation%20%28disambiguation%29
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Canonical Transformation may refer to:
Symplectomorphism, a mathematical treatment
Canonical transformation, a physics treatment
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https://en.wikipedia.org/wiki/Independence%20system
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In combinatorial mathematics, an independence system is a pair , where is a finite set and is a collection of subsets of (called the independent sets or feasible sets) with the following properties:
The empty set is independent, i.e., . (Alternatively, at least one subset of is independent, i.e., .)
Every subset of an independent set is independent, i.e., for each , we have . This is sometimes called the hereditary property, or downward-closedness.
Another term for an independence system is an abstract simplicial complex.
Relation to other concepts
A pair , where is a finite set and is a collection of subsets of is also called a hypergraph. When using this terminology, the elements in the set are called vertices and elements in the family are called hyperedges. So an independence system can be defined shortly as a downward-closed hypergraph.
An independence system with an additional property called the augmentation property or the independent set exchange property yields a matroid. The following expression summarizes the relations between the terms:HYPERGRAPHS INDEPENDENCE-SYSTEMS ABSTRACT-SIMPLICIAL-COMPLEXES MATROIDS.
References
.
Combinatorics
Hypergraphs
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https://en.wikipedia.org/wiki/Constraint%20counting
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In mathematics, constraint counting is counting the number of constraints in order to compare it with the number of variables, parameters, etc. that are free to be determined, the idea being that in most cases the number of independent choices that can be made is the excess of the latter over the former.
For example, in linear algebra if the number of constraints (independent equations) in a system of linear equations equals the number of unknowns then precisely one solution exists; if there are fewer independent equations than unknowns, an infinite number of solutions exist; and if the number of independent equations exceeds the number of unknowns, then no solutions exist.
In the context of partial differential equations, constraint counting is a crude but often useful way of counting the number of free functions needed to specify a solution to a partial differential equation.
Partial differential equations
Consider a second order partial differential equation in three variables, such as the two-dimensional wave equation
It is often profitable to think of such an equation as a rewrite rule allowing us to rewrite arbitrary partial derivatives of the function using fewer partials than would be needed for an arbitrary function. For example, if satisfies the wave equation, we can rewrite
where in the first equality, we appealed to the fact that partial derivatives commute.
Linear equations
To answer this in the important special case of a linear partial differential
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https://en.wikipedia.org/wiki/Signed%20graph
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In the area of graph theory in mathematics, a signed graph is a graph in which each edge has a positive or negative sign.
A signed graph is balanced if the product of edge signs around every cycle is positive. The name "signed graph" and the notion of balance appeared first in a mathematical paper of Frank Harary in 1953. Dénes Kőnig had already studied equivalent notions in 1936 under a different terminology but without recognizing the relevance of the sign group.
At the Center for Group Dynamics at the University of Michigan, Dorwin Cartwright and Harary generalized Fritz Heider's psychological theory of balance in triangles of sentiments to a psychological theory of balance in signed graphs.
Signed graphs have been rediscovered many times because they come up naturally in many unrelated areas. For instance, they enable one to describe and analyze the geometry of subsets of the classical root systems. They appear in topological graph theory and group theory. They are a natural context for questions about odd and even cycles in graphs. They appear in computing the ground state energy in the non-ferromagnetic Ising model; for this one needs to find a largest balanced edge set in Σ. They have been applied to data classification in correlation clustering.
Fundamental theorem
The sign of a path is the product of the signs of its edges. Thus a path is positive only if there are an even number of negative edges in it (where zero is even). In the mathematical balance theor
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https://en.wikipedia.org/wiki/Colored%20matroid
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In mathematics, a colored matroid is a matroid whose elements are labeled from a set of colors, which can be any set that suits the purpose, for instance the set of the first n positive integers, or the sign set {+, −}.
The interest in colored matroids is through their invariants, especially the colored Tutte polynomial, which generalizes the Tutte polynomial of a signed graph of .
There has also been study of optimization problems on matroids where the objective function of the optimization depends on the set of colors chosen as part of a matroid basis.
See also
Bipartite matroid
Rota's basis conjecture
References
Matroid theory
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https://en.wikipedia.org/wiki/Biased%20graph
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In mathematics, a biased graph is a graph with a list of distinguished circles (edge sets of simple cycles), such that if two circles in the list are contained in a theta graph, then the third circle of the theta graph is also in the list. A biased graph is a generalization of the combinatorial essentials of a gain graph and in particular of a signed graph.
Formally, a biased graph Ω is a pair (G, B) where B is a linear class of circles; this by definition is a class of circles that satisfies the theta-graph property mentioned above.
A subgraph or edge set whose circles are all in B (and which contains no half-edges) is called balanced. For instance, a circle belonging to B is balanced and one that does not belong to B is unbalanced.
Biased graphs are interesting mostly because of their matroids, but also because of their connection with multiary quasigroups. See below.
Technical notes
A biased graph may have half-edges (one endpoint) and loose edges (no endpoints). The edges with two endpoints are of two kinds: a link has two distinct endpoints, while a loop has two coinciding endpoints.
Linear classes of circles are a special case of linear subclasses of circuits in a matroid.
Examples
If every circle belongs to B, and there are no half-edges, Ω is balanced. A balanced biased graph is (for most purposes) essentially the same as an ordinary graph.
If B is empty, Ω is called contrabalanced. Contrabalanced biased graphs are related to bicircular matroids.
If B
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https://en.wikipedia.org/wiki/Bryan%20Higgins
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Bryan Higgins (1741 – 1818) was an Irish natural philosopher in chemistry.
He was born in Collooney, County Sligo, Ireland. His father (d. 1777) was also called Dr. Bryan Higgins. Higgins entered the University of Leiden in 1765, whence he qualified as a doctor of physics. He subsequently ran a School of Practical Chemistry at 13 Greek Street, Soho, London during the 1770s, which was patronised by the then Duke of Northumberland amongst others. He was more of a speculator than an experimenter, and published many works on chemistry and related disciplines. Joseph Priestley was an attendee of Higgins's lectures, but the two became enemies following a dispute over experiments on air (Priestley at the time was working on his six-volume tome Experiments and Observations on Different Kinds of Air).
At some point between 1780 and 1790, Higgins visited Saint Petersburg at the favour of Catherine the Great, Empress of Russia. He returned to London in January 1794 to continue his lectures at the School of Practical Chemistry.
In 1779, Higgins obtained a patent for a cheap and durable cement, "...composed of sand and lime, and a certain proportion of bone-ashes, the lime being slaked with limewater instead of common water, and the mixture made use of as rapidly as possible after being made".
In 1797, Higgins was hired by a public committee in Jamaica for the improvement of the manufacture of muscovado and rum. He resided in Jamaica from 1797 to 1799.
According to Higgins's atomic t
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https://en.wikipedia.org/wiki/MISG
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MISG may refer to:
The Mathematics in Industry Study Group, an annual workshop now held in Australia, under the wing of Australian and NZ Industrial Applied Maths ANZIAM
Malaysian Islamic Study Group, a U.S.-based student organization
Military Intelligence and Security Group, the former secret police agency of the Philippines
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https://en.wikipedia.org/wiki/ALK
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ALK or Alk may refer to:
ALK Airlines, a Bulgarian charter airline
Anaplastic lymphoma kinase, a human gene
Alk-, a root word used in organic chemistry
Alaska Air Group ticker symbol
Aslockton railway station, Nottinghamshire, England, National Rail code
ALK or ALK-Abelló, a Danish pharmaceutical company
Automated lamellar keratoplasty, a type of eye surgery
Alk, Albania, a village
Alk, Iran, a village in Kurdistan Province
Alk-e Kohneh ("Old Alk"), a village in Kurdistan Province, Iran
, a German cargo ship in service 1928–45
A sailing ship renamed as Albatross
ALK, the ICAO Code for SriLankan Airlines
See also
ALK1-7, an activin receptor-like kinase protein e.g. ALK1
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https://en.wikipedia.org/wiki/Semyon%20Aranovich%20Gershgorin
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Semyon Aronovich Gershgorin (August 24, 1901 – May 30, 1933) was a Soviet (born in Pruzhany, Belarus, Russian Empire) mathematician. He began as a student at the Petrograd Technological Institute in 1923, became a Professor in 1930, and was given an appointment at the Leningrad Mechanical Engineering Institute in the same year. His contributions include the Gershgorin circle theorem.
The spelling of S. A. Gershgorin's name (Семён Аронович Гершгорин) has been transliterated in several different ways, including Geršgorin, Gerschgorin, Gerszgorin, Gershgorin, Gershgeroff, Qureshin, Gershmachnow and from the Yiddish spelling to Hirshhorn and Hirschhorn.
The authors of his obituary wrote about Gershgorin's death at the very young age of 31: "A vigorous, stressful job weakened Semyon Aranovich's health; he succumbed to an accidental illness."
References
External links
.
1901 births
1933 deaths
Soviet mathematicians
20th-century Belarusian mathematicians
Belarusian Jews
People from Pruzhany
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https://en.wikipedia.org/wiki/Phil%20Karn
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Phil Karn (born October 4, 1956) is a retired American engineer from Lutherville, Maryland. He earned a bachelor's degree in electrical engineering from Cornell University in 1978 and a master's degree in electrical engineering from Carnegie Mellon University in 1979. From 1979 until 1984, Karn worked at Bell Labs in Naperville, Illinois, and Murray Hill, New Jersey. From 1984 until 1991, he was with Bell Communications Research in Morristown, New Jersey. From 1991 through to his retirement, he worked at Qualcomm in San Diego, where he specialized in wireless data networking protocols, security, and cryptography.
He is currently the President/CEO of Amateur Radio Digital Communications (ARDC), a non-profit foundation funded by the sale of part of its IP address space (44/8). ARDC manages the remaining portion of its address space by providing financial grants to amateur radio and related groups.
He has been an active contributor in the Internet Engineering Task Force, especially in security, and to the Internet architecture. He is the author or co-author of at least 6 RFCs, and is cited as contributing to many more. He is the inventor of Karn's Algorithm, a method for calculating the round trip time for IP packet retransmission. In 1991, Thomas Alexander Iannelli's Master's thesis judged Karn's KA9Q NOS software as more suitable for deployment than an Air Force Institute of Technology packet radio system. In 1990, Karn was one of the first to predict that the use of wire
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https://en.wikipedia.org/wiki/Control%20knob
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A control knob is a rotary device used to provide manual input adjustments to a mechanical/electrical system when grasped and turned by a human operator, so that differing extent of knob rotation corresponds to different desired input. Control knobs are a simpler type of input hardware and one of the most common components in control systems, and are found on all sorts of devices from taps and gas stoves to optical microscopes, potentiometers, radio tuners and digital cameras, as well as in aircraft cockpits.
Operation
A control knob works by turning a shaft which connects to the component which produces the actual input. Common control components used include potentiometers, variable capacitors, and rotary switches. An example where the knob does not produce a variation in an electrical signal may be found in many toasters, where the darkness knob moves the thermostat in such a way as to change the temperature at which it opens and releases the cooked toast. Some similar controls produce similar inputs using different geometry; for example, the knob may be replaced by a lever which is moved through an angle. Another example is the sliding controls which frequently replace knobs as level controls in audio equipment.
Feedback
The use of knobs is an important aspect of the design of user interfaces in these devices. Particular attention needs to be paid to the feedback to the operator from the adjustments being made. The use of a pointer on the knob in conjunction with a scal
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https://en.wikipedia.org/wiki/Argonaut%20class%20reactor
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The Argonaut class reactor is a design of small nuclear research reactor. Many have been built throughout the world, over a wide range of power levels. Its functions are to teach nuclear reactor theory, nuclear physics and for use in engineering laboratory experiments.
Description
The original Argonaut (Argonne Nuclear Assembly for University Training) was built at Argonne National Laboratory and went critical for the first time on February 9, 1957. It was shut down in 1972. This reactor was rated for 10 kilowatts.
See also
UF Training Reactor
More Hall Annex
Citations
References
Further reading
Argonne National Laboratory
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https://en.wikipedia.org/wiki/Peter%20Cope
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Peter Roland Cope (7 December 1921 – 4 April 2005) was the last surviving test pilot from the Avro Arrow program.
Born in Croydon, England, Cope signed up for the Royal Air Force in 1939 after graduating from Croydon College with a degree in science and applied mathematics.
Due to the over stretched pilot training in the UK in August 1941 Cope was sent for training with the United States Army Air Corps on the Vultee BT-13 Valiant at Maxwell Field, Alabama. Cope returned to England in 1942 and after advanced fighter training joined 170 Squadron flying the North American Mustang.
Cope attended No. 5 Course at the Empire Test Pilots' School in 1946/1947.
He was hired by Armstrong-Whitworth Company to test the Gloster Meteor
In April 1952 Cope moved to Canada to work for A.V.Roe Canada. Because of his experience in the war he became the unofficial armament development pilot.
Cope was one of four pilots assigned to test fly the Arrow, and flew it five times.
In 1960 Cope left Avro for Boeing, from which he retired in 1986.
Cope died in Bellevue, Washington.
Notes
References
1921 births
2005 deaths
English aviators
English test pilots
Royal Air Force officers
Alumni of Croydon College
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https://en.wikipedia.org/wiki/Lambda%20transition
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The λ (lambda) universality class is a group in condensed matter physics. It regroups several systems possessing strong analogies, namely, superfluids, superconductors and smectics (liquid crystals). All these systems are expected to belong to the same universality class for the thermodynamic critical properties of the phase transition. While these systems are quite different at the first glance, they all are described by similar formalisms and their typical phase diagrams are identical.
See also
Superfluid
Superconductor
Liquid crystal
Phase transition
Renormalization group
Topological defect
References
Books
Chaikin P. M. and Lubensky T. C. Principles of Condensed Matter Physics (Cambridge University Press, Cambridge) 1995, sect.9.
Feynman R. P. Progress in Low Temperature Physics Vol.1, edited by C. Gorter (North Holland, Amsterdam) 1955.
Journal articles
Translated as:
Condensed matter physics
Critical phenomena
Phase transitions
Phases of matter
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https://en.wikipedia.org/wiki/Polymethylhydrosiloxane
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Polymethylhydrosiloxane (PMHS) is a polymer with the general structure . It is used in organic chemistry as a mild and stable reducing agent easily transferring hydrides to metal centers and a number of other reducible functional groups. A variety of related materials are available under the following CAS registry numbers 9004-73-3, 16066-09-4, 63148-57-2, 178873-19-3. These include the tetramer (), copolymers of dimethylsiloxane and methylhydrosiloxane, and trimethylsilyl terminated materials.
This material is prepared by the hydrolysis of monomethyldichlorosilane CAS#: 75-54-7:
The related polymer polydimethylsiloxane (PDMS) is made similarly, but lacking bonds, it exhibits no reducing properties. Dimethyldichlorosilane CAS#: 75-78-5 is then used instead of monomethyldichlorosilane CAS#: 75-54-7.
Illustrative of its use, PMHS is used for in situ conversion of tributyltin oxide to tributyltin hydride:
References
Further reading
Larson, G. L.; Fry, J. L., "Ionic and organometallic-catalyzed organosilane reductions", Organic Reactions 2008, 71, 1-737.
Silicones
Reagents for organic chemistry
Siloxanes
Reducing agents
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https://en.wikipedia.org/wiki/Kummer%E2%80%93Vandiver%20conjecture
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In mathematics, the Kummer–Vandiver conjecture, or Vandiver conjecture, states that a prime p does not divide the class number hK of the maximal real subfield of the p-th cyclotomic field.
The conjecture was first made by Ernst Kummer on 28 December 1849 and 24 April 1853 in letters to Leopold Kronecker, reprinted in , and independently rediscovered around 1920 by Philipp Furtwängler and ,
As of 2011, there is no particularly strong evidence either for or against the conjecture and it is unclear whether it is true or false, though it is likely that counterexamples are very rare.
Background
The class number h of the cyclotomic field is a product of two integers h1 and h2, called the first and second factors of the class number, where h2 is the class number of the maximal real subfield of the p-th cyclotomic field. The first factor h1 is well understood and can be computed easily in terms of Bernoulli numbers, and is usually rather large. The second factor h2 is not well understood and is hard to compute explicitly, and in the cases when it has been computed it is usually small.
Kummer showed that if a prime p does not divide the class number h, then Fermat's Last Theorem holds for exponent p.
The Kummer–Vandiver conjecture states that p does not divide the second factor h2.
Kummer showed that if p divides the second factor, then it also divides the first factor. In particular the Kummer–Vandiver conjecture holds for regular primes (those for which p does not di
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https://en.wikipedia.org/wiki/Farkas%27%20lemma
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In mathematics, Farkas' lemma is a solvability theorem for a finite system of linear inequalities. It was originally proven by the Hungarian mathematician Gyula Farkas.
Farkas' lemma is the key result underpinning the linear programming duality and has played a central role in the development of mathematical optimization (alternatively, mathematical programming). It is used amongst other things in the proof of the Karush–Kuhn–Tucker theorem in nonlinear programming.
Remarkably, in the area of the foundations of quantum theory, the lemma also underlies the complete set of Bell inequalities in the form of necessary and sufficient conditions for the existence of a local hidden-variable theory, given data from any specific set of measurements.
Generalizations of the Farkas' lemma are about the solvability theorem for convex inequalities, i.e., infinite system of linear inequalities. Farkas' lemma belongs to a class of statements called "theorems of the alternative": a theorem stating that exactly one of two systems has a solution.
Statement of the lemma
There are a number of slightly different (but equivalent) formulations of the lemma in the literature. The one given here is due to Gale, Kuhn and Tucker (1951).
Here, the notation means that all components of the vector are nonnegative.
Example
Let , and The lemma says that exactly one of the following two statements must be true (depending on and ):
There exist , such that and , or
There exist such that , , and
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https://en.wikipedia.org/wiki/Revolutionary%20Vol.%202
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Revolutionary Vol. 2 is the second studio album by American rapper Immortal Technique. It was released on November 18, 2003, through Viper Records, serving as a sequel to his 2001 debut Revolutionary Vol. 1. Recording sessions took place at Viper Studios in New York. Production was handled by SouthPaw, Daneja, Domingo, Metaphysics, Omen and 44 Caliber, with Jonathan Stuart and Immortal Technique serving as executive producers. It features guest appearances from Mumia Abu-Jamal, Akir, C-Rayz Walz, Diabolic, Jean Grae, Loucipher, Poison Pen, Pumpkinhead and Tonedeff.
Revolutionary Vol. 2 attacks the United States government, especially the Bush Administration. Immortal Technique claimed in an interview to have sold more than 85,000 copies. The album features Mumia Abu-Jamal, who introduces the album and also provides a speech about hip hop's relationship to homeland security. Issues repeatedly discussed on the album include poverty, drug trade, slave labor, censorship, corporate control over the media (including hip hop), the September 11th World Trade Center attacks, racism, the prison industrial complex and class struggle.
Revolutionary Vol. 1 and Vol. 2 were re-pressed in 2004 via Babygrande Records.
Track listing
References
External links
Viper Records official website
2003 albums
Sequel albums
Nature Sounds albums
Immortal Technique albums
Albums produced by Domingo (producer)
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https://en.wikipedia.org/wiki/Singly%20and%20doubly%20even
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In mathematics an even integer, that is, a number that is divisible by 2, is called evenly even or doubly even if it is a multiple of 4, and oddly even or singly even if it is not. The former names are traditional ones, derived from ancient Greek mathematics; the latter have become common in recent decades.
These names reflect a basic concept in number theory, the 2-order of an integer: how many times the integer can be divided by 2. This is equivalent to the multiplicity of 2 in the prime factorization.
A singly even number can be divided by 2 only once; it is even but its quotient by 2 is odd.
A doubly even number is an integer that is divisible more than once by 2; it is even and its quotient by 2 is also even.
The separate consideration of oddly and evenly even numbers is useful in many parts of mathematics, especially in number theory, combinatorics, coding theory (see even codes), among others.
Definitions
The ancient Greek terms "even-times-even" () and "even-times-odd" ( or ) were given various inequivalent definitions by Euclid and later writers such as Nicomachus. Today, there is a standard development of the concepts. The 2-order or 2-adic order is simply a special case of the p-adic order at a general prime number p; see p-adic number for more on this broad area of mathematics. Many of the following definitions generalize directly to other primes.
For an integer n, the 2-order of n (also called valuation) is the largest natural number ν such that 2ν divides n
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https://en.wikipedia.org/wiki/William%20Prager
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William Prager, (before 1940) Willy Prager, (May 23, 1903 in Karlsruhe – March 17, 1980 in Zurich) was a German-born US applied mathematician. In the field of mechanics he is well known for the Drucker–Prager yield criterion.
Willy Prager studied civil engineering at the Technische Universität Darmstadt and received his diploma in 1925. He received his doctorate in 1926 and worked as a research assistant in the field of mechanics from 1925 to 1929. From 1927 to 1929 he habilitated. He was a deputy director at University of Göttingen, professor at Karlsruhe, University of Istanbul, the University of California, San Diego and Brown University, where he advised Bernard Budiansky. Prager was also on a sabbatical at IBM's research lab in Zurich.
The Society of Engineering Science has awarded the William Prager Medal in Solid Mechanics since 1983 in his honor. In 1957, he received a Guggenheim Fellowship.
Works
Beitrag zur Kinematik des Raumfachwerks, 1926, dissertation
"Dynamik der Stabwerke" (with K. Hohenemser), 1933
"Mechanique des solides isotropes", 1937
Prager, William (1961). Introduction to Mechanics of Continua. Ginn and Company.
External links
William Prager - Encyclopedia Brunoniana - Brown University
References for William Prager
Mac Tutor Bio for William Prager
See also
Plastic limit theorems
References
1903 births
1980 deaths
20th-century German mathematicians
20th-century American mathematicians
German emigrants to the United States
German expatri
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https://en.wikipedia.org/wiki/Bernard%20Cohen%20%28physicist%29
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Bernard Leonard Cohen (June 14, 1924 – March 17, 2012) was born in Pittsburgh, and was Professor Emeritus of Physics at the University of Pittsburgh. Professor Cohen was a staunch opponent of the so-called Linear no-threshold model (LNT) which postulates there exists no safe threshold for radiation exposure. His view which has support from a minority. He died in March 2012.
No-threshold and plutonium toxicity debates
Cohen claimed: "All estimates of the cancer risk from low level radiation are based on the linear-no threshold theory (LNT) which is based solely on largely discredited concepts of radiation carcinogenesis, with no experimental verification in the low dose region of the most important applications. These risk estimates are now leading to the expenditure of tens of billions of dollars to protect against dangers whose existence is highly questionable. It is therefore of utmost importance to test the validity of this theory."
A conclusion, with an update to the landmark study published 1995, continues: "Since no other plausible explanation has been found after years of effort by myself and others, I conclude that the most plausible explanation for our discrepancy is that the linear-no threshold theory fails, grossly over-estimating the cancer risk in the low dose, low dose rate region. There are no other data capable of testing the theory in that region.
An easy answer to the credibility of this conclusion would be for someone to suggest a potential not implausib
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https://en.wikipedia.org/wiki/Homoleptic
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In inorganic chemistry, a homoleptic chemical compound is a metal compound with all ligands identical. The term uses the "homo-" prefix to indicate that something is the same for all. Any metal species which has more than one type of ligand is heteroleptic.
Some compounds with names that suggest that they are homoleptic are in fact heteroleptic, because they have ligands in them which are not featured in the name. For instance dialkyl magnesium complexes, which are found in the equilibrium which exists in a solution of a Grignard reagent in an ether, have two ether ligands attached to each magnesium centre. Another example is a solution of trimethyl aluminium in an ether solvent (such as THF); similar chemistry should be expected for a triaryl or trialkyl borane.
It is possible for some ligands such as DMSO to bind with two or more different coordination modes. It would still be reasonable to consider a complex which has only one type of ligand but with different coordination modes to be homoleptic. For example, the complex dichlorotetrakis(dimethyl sulfoxide)ruthenium(II) features DMSO coordinating via both sulfur and oxygen atoms (though this is not homoleptic since there are also chloride ligands).
Examples
Chromium carbonyl
Ferrocyanide
Iron pentacarbonyl
Nickel carbonyl
Tetrakis(triphenylphosphine)palladium(0)
Ferrocene
Uranium hexafluoride
tetraethyl lead
tetramethyl lead
tetrabutyl tin
trimethylaluminium
dimethylmercury
Diethylzinc
triethylborane
Ch
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https://en.wikipedia.org/wiki/MV-algebra
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In abstract algebra, a branch of pure mathematics, an MV-algebra is an algebraic structure with a binary operation , a unary operation , and the constant , satisfying certain axioms. MV-algebras are the algebraic semantics of Łukasiewicz logic; the letters MV refer to the many-valued logic of Łukasiewicz. MV-algebras coincide with the class of bounded commutative BCK algebras.
Definitions
An MV-algebra is an algebraic structure consisting of
a non-empty set
a binary operation on
a unary operation on and
a constant denoting a fixed element of
which satisfies the following identities:
and
By virtue of the first three axioms, is a commutative monoid. Being defined by identities, MV-algebras form a variety of algebras. The variety of MV-algebras is a subvariety of the variety of BL-algebras and contains all Boolean algebras.
An MV-algebra can equivalently be defined (Hájek 1998) as a prelinear commutative bounded integral residuated lattice satisfying the additional identity
Examples of MV-algebras
A simple numerical example is with operations and In mathematical fuzzy logic, this MV-algebra is called the standard MV-algebra, as it forms the standard real-valued semantics of Łukasiewicz logic.
The trivial MV-algebra has the only element 0 and the operations defined in the only possible way, and
The two-element MV-algebra is actually the two-element Boolean algebra with coinciding with Boolean disjunction and with Boolean negation. In fact a
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https://en.wikipedia.org/wiki/MBCS
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MBCS may refer to:
Member of the Chartered Institute for I.T., denoting membership at a professional level
Multi Byte Character Set, a class of character encodings in computing
Marine Biology Case Study, a discontinued case study in the AP Computer Science program
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https://en.wikipedia.org/wiki/Bioirrigation
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Bioirrigation refers to the process of benthic organisms flushing their burrows with overlying water. The exchange of dissolved substances between the porewater and overlying seawater that results is an important process in the context of the biogeochemistry of the oceans.
Marine coastal ecosystems often have organisms that destabilize sediment. They change the physical state of the sediment. Thus improving the conditions for other organisms and themselves. These organisms often also cause bioturbation, which is commonly used interchangeably or in reference with bioirrigation.
Bioirrigation works as two different processes. These processes are known as particle reworking and ventilation, which is the work of benthic macro-invertebrates (usually ones that burrow). This particle reworking and ventilation is caused by the organisms when they feed (faunal feeding), defecate, burrow, and respire.
Bioirrigation is responsible for a large amount of oxidative transport and has a large impact on biogeochemical cycles.
Bioirrigation's Role in Elemental Cycling
Bioirrigation is a main component in element cycling. Some of these elements include: Magnesium, Nitrogen, Calcium, Strontium, Molybdenum, and Uranium. Other elements are only displaced at certain steps in the bioirrigation process. Aluminium, Iron, Cobalt, Copper, Zinc, and Cerium are all affected at the start of the process, when the larvae begins to dig into the sediment. While Manganese, Nickel, Arsenic, Cadmium and Cae
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https://en.wikipedia.org/wiki/Schottky%20effect
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The Schottky effect or field enhanced thermionic emission is a phenomenon in condensed matter physics named after Walter H. Schottky. In electron emission devices, especially electron guns, the thermionic electron emitter will be biased negative relative to its surroundings. This creates an electric field of magnitude F at the emitter surface. Without the field, the surface barrier seen by an escaping Fermi-level electron has height W equal to the local work-function. The electric field lowers the surface barrier by an amount ΔW, and increases the emission current. It can be modeled by a simple modification of the Richardson equation, by replacing W by (W − ΔW). This gives the equation
where J is the emission current density, T is the temperature of the metal, W is the work function of the metal, k is the Boltzmann constant, qe is the Elementary charge, ε0 is the vacuum permittivity, and AG is the product of a universal constant A0 multiplied by a material-specific correction factor λR which is typically of order 0.5.
Electron emission that takes place in the field-and-temperature-regime where this modified equation applies is often called Schottky emission. This equation is relatively accurate for electric field strengths lower than about 108 V m−1. For electric field strengths higher than 108 V m−1, so-called Fowler–Nordheim (FN) tunneling begins to contribute significant emission current. In this regime, the combined effects of field-enhanced thermionic and field emiss
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https://en.wikipedia.org/wiki/Catalytic%20cycle
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In chemistry, a catalytic cycle is a multistep reaction mechanism that involves a catalyst. The catalytic cycle is the main method for describing the role of catalysts in biochemistry, organometallic chemistry, bioinorganic chemistry, materials science, etc.
Since catalysts are regenerated, catalytic cycles are usually written as a sequence of chemical reactions in the form of a loop. In such loops, the initial step entails binding of one or more reactants by the catalyst, and the final step is the release of the product and regeneration of the catalyst. Articles on the Monsanto process, the Wacker process, and the Heck reaction show catalytic cycles.
A catalytic cycle is not necessarily a full reaction mechanism. For example, it may be that the intermediates have been detected, but it is not known by which mechanisms the actual elementary reactions occur.
Precatalysts
Precatalysts are not catalysts but are precursors to catalysts. Precatalysts are converted in the reactor to the actual catalytic species. The identification of catalysts vs precatalysts is an important theme in catalysis research.
The conversion of a precatalyst to a catalyst is often called catalyst activation. Many metal halides are precatalysts for alkene polymerization, see Kaminsky catalyst and Ziegler-Natta catalysis. The precatalysts, e.g. titanium trichloride, are activated by organoaluminium compounds, which function as catalyst activators. Metal oxides are often classified as catalysts, but i
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https://en.wikipedia.org/wiki/RVM
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RVM may refer to:
Companies and organizations
Reich Ministry of Transport (), German government agency (1919–1945)
Religious of the Virgin Mary, an ecclesiastical community of Filipino Roman Catholic women
Rayo Vallecano de Madrid, a football club
Mathematics, science, medicine and technology
Red Velvet Mite, arachnids known for their bright red colors
Rostral ventromedial medulla, a group of neurons in the medulla oblongata
Real-valued measurable, an axiom asserting the existence of a real-valued measurable cardinal number
Reference Verification Methodology, a method for functional verification of complex designs
Relevance vector machine, a machine learning technique.
Reverse vending machine, a sensor-based machine for sorting and recycling
Ruby Version Manager, a software tool to manage Ruby programming language versions
"RVM", abbreviation for the Jikes Research Virtual Machine
.rvm - file extension associated with PDMS
Other uses
"RVM", station code for Richmond Main Street Station, Richmond, Virginia
Royal Victorian Medal, Commonwealth military decoration post-nominal letters
See also
RVN (disambiguation)
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https://en.wikipedia.org/wiki/Non-covalent%20interaction
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In chemistry, a non-covalent interaction differs from a covalent bond in that it does not involve the sharing of electrons, but rather involves more dispersed variations of electromagnetic interactions between molecules or within a molecule. The chemical energy released in the formation of non-covalent interactions is typically on the order of 1–5 kcal/mol (1000–5000 calories per 6.02 molecules). Non-covalent interactions can be classified into different categories, such as electrostatic, π-effects, van der Waals forces, and hydrophobic effects.
Non-covalent interactions are critical in maintaining the three-dimensional structure of large molecules, such as proteins and nucleic acids. They are also involved in many biological processes in which large molecules bind specifically but transiently to one another (see the properties section of the DNA page). These interactions also heavily influence drug design, crystallinity and design of materials, particularly for self-assembly, and, in general, the synthesis of many organic molecules.
The non-covalent interactions may occur between different parts of the same molecule (e.g. during protein folding) or between different molecules and therefore are discussed also as intermolecular forces.
Electrostatic interactions
Ionic
Ionic interactions involve the attraction of ions or molecules with full permanent charges of opposite signs. For example, sodium fluoride involves the attraction of the positive charge on sodium (Na+) with
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https://en.wikipedia.org/wiki/Menshutkin%20reaction
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In organic chemistry, the Menshutkin reaction converts a tertiary amine into a quaternary ammonium salt by reaction with an alkyl halide. Similar reactions occur when tertiary phosphines are treated with alkyl halides.
The reaction is the method of choice for the preparation of quaternary ammonium salts. Some phase transfer catalysts (PTC) can be prepared according to the Menshutkin reaction, for instance the synthesis of triethyl benzyl ammonium chloride (TEBA) from triethylamine and benzyl chloride:
Scope
Reactions are typically conducted in polar solvents such as alcohols. Alkyl iodides are superior alkylating agents relative to the bromides, which in turn are superior to chlorides. As is typical for an SN2 process, benzylic, allylic, and α-carbonylated alkyl halides are excellent reactants. Even though alkyl chlorides are poor alkylating agents (gem-dichlorides especially so), amines should not be handled in chlorinated solvents such as dichloromethane and dichloroethane, especially at high temperatures, due to the possibility of a Menshutkin reaction. (Sometimes, kinetically facile reactions like acylations are sometimes conducted in chlorinated solvents nonetheless.) Highly nucleophilic tertiary amines like DABCO will react with dichloromethane at room temperature overnight and at reflux (39-40 °C) over several hours to give the quaternized product (see the article on Selectfluor). Due to steric hindrance and unfavorable electronic properties, chloroform react
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https://en.wikipedia.org/wiki/Pete%20Dexter
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Pete Dexter (born July 22, 1943) is an American novelist. He won the U.S. National Book Award in 1988 for his novel Paris Trout.
Early life and education
Dexter was born in Pontiac, Michigan. His father died when Dexter was four and he and his mother moved to Milledgeville, Georgia, where she married a college physics professor. He earned his undergraduate degree in 1969 from the University of South Dakota, which awarded him an honorary Doctor of Letters and
Literature in 2010.
Career
He worked for what is now The Palm Beach Post in West Palm Beach, Florida, but quit in 1972 because the paper's owners forced the editorial page editor to endorse Richard Nixon over George McGovern. He was a columnist for the Philadelphia Daily News, from 1974 to 1986, The Sacramento Bee, and syndicated to many newspapers such as the Seattle Post-Intelligencer.
Dexter began writing fiction after a life-changing 1981 incident in the Devil's Pocket, neighborhood in South Philadelphia, in which a mob of locals armed with baseball bats beat him severely. The perpetrators were upset by Dexter's recent column about a murder involving a drug deal-gone-wrong, published on December 9, 1981, in the Philadelphia Daily News,
A couple of weeks ago, a kid named Buddy Lego was found dead in Cobbs Creek," wrote Dexter. "It was a Sunday afternoon. He was from the neighborhood, a good athlete, a nice kid. Stoned all the time. The kind of kid you think you could have saved.
The kid's mother called Dexter, ne
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https://en.wikipedia.org/wiki/Two-stream%20instability
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The two-stream instability is a very common instability in plasma physics. It can be induced by an energetic particle stream injected in a plasma, or setting a current along the plasma so different species (ions and electrons) can have different drift velocities. The energy from the particles can lead to plasma wave excitation.
Two-stream instability can arise from the case of two cold beams, in which no particles are resonant with the wave, or from two hot beams, in which there exist particles from one or both beams which are resonant with the wave.
Two-stream instability is known in various limiting cases as beam-plasma instability, beam instability, or bump-on-tail instability.
Dispersion relation in cold-beam limit
Consider a cold, uniform, and unmagnetized plasma, where ions are stationary and the electrons have velocity , that is, the reference frame is moving with the ion stream. Let the electrostatic waves be of the form:
Applying linearization techniques to the equation of motions for both species, to the equation of continuity, and Poisson's equation, and introducing the spatial and temporal harmonic operators , we can get the following expression:
which represents the dispersion relation for longitudinal waves, and represents a quartic equation in . The roots can be expressed in the form:
If the imaginary part () is zero, then the solutions represent all the possible modes, and there is no temporal wave growth or damping at all:
If , that is, any of the r
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https://en.wikipedia.org/wiki/Dentate
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Dentate may refer to:
A species having dentition
An energy-dissipating baffle block in a spillway
An individual not being edentulous
Dentate gyrus of the hippocampus
Dentate nucleus of the cerebellum
Denticity in chemistry
Dentate leaf, a kind of leaf margin
Dentate wing, a wing shape on Lepidoptera species
See also
Denticulate (disambiguation)
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https://en.wikipedia.org/wiki/Golgi%20cell
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In neuroscience, Golgi cells are inhibitory interneurons found within the granular layer of the cerebellum. They were first identified as inhibitory in 1964.
It was also the first example of an inhibitory feedback network, where the inhibitory interneuron was identified anatomically.
These cells synapse onto the dendrite of granule cells and unipolar brush cells. They receive excitatory input from mossy fibres, also synapsing on granule cells, and parallel fibers, which are long granule cell axons. Thereby this circuitry allows for feed-forward and feed-back inhibition of granule cells.
The main synapse made by these cells is a synapse onto the mossy fibre - granule cell excitatory synapse in a glomerulus. The glomerulus is made up of the mossy fibre terminal, granule cell dendrites, the Golgi terminal and is enclosed by a glial coat.
The Golgi cell acts by altering the mossy fibre - granule cell synapse.
The Golgi cells use GABA as their neurotransmitter. The basal level of GABA produces a postsynaptic leak conductance by tonically activating alpha 6-containing GABA-A receptors on the granule cell.
These high-affinity receptors are located both synaptically and extrasynaptically on the granule cell. The synaptic receptors mediate phasic contraction, duration of around 20-30ms whereas the extrasynapatic receptors mediate tonic inhibition of around 200ms, and are activated by synapse spill over.
Additionally the GABA acts on GABA-B receptors which are located presynaptica
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https://en.wikipedia.org/wiki/Test%20theory
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In experimental physics, a test theory tells experimenters how to perform particular comparisons between specific theories or classes of theory.
Without a good reference test theory, these experiments can be difficult to construct. Different theories often define relationships and parameters in different, often incompatible, ways. Sometimes, physical theories and models that nominally produce significantly diverging predictions can be found to produce very similar, even identical, predictions, once definitional differences are taken into account.
A good test theory should identify potential sources of definitional bias in the way that experiments are constructed. It should also be able to deal with a wide range of possible objections to experimental tests based upon it. Discovery that a test theory has serious omissions can undermine the validity of experimental work that is designed according to that theory.
Examples
Parameterized post-Newtonian formalism is used to compare theories of gravity.
Test theories of special relativity are useful when designing experiments to look for possible violations of Poincare symmetry.
Physics experiments
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https://en.wikipedia.org/wiki/Cerberus%20%28disambiguation%29
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Cerberus is a mythic multi-headed dog.
Cerberus may also refer to:
Astronomy
Cerberus (constellation), a group of stars
Cerberus (Martian albedo feature), a dark spot on Mars
Kerberos (moon), a moon of Pluto (sometimes mistakenly spelled Cerberus)
1865 Cerberus, an asteroid
Biology
Cerberus (protein), involved in embryological development
Cerberus (snake), a genus of snakes
Cerberus (virus) (BQ.1.1), a variant of the SARS-CoV-2 Omicron virus variant
Art, entertainment, and media
Fictional entities
Cerberus (Cardcaptor Sakura), a character in the manga and anime series Cardcaptor Sakura
Cerberus (Eyeshield 21), a fictional dog in the manga and anime series Eyeshield 21
Cerberus (Mass Effect), a fictional anthropocentric organization in the video game franchise Mass Effect
Cerberus, a character and boss opponent in the video game Blood
Cerberus, a boss in the video game Devil May Cry 3: Dante's Awakening
Cerberus, a fictional zombie in the manga and anime series One Piece
Cerberus, a paradigm consisting of three Commandos (Attackers) in the video game Final Fantasy XIII and Final Fantasy XIII-2
Cerberus, a boss in the video game Old School RuneScape
Cerberus, a fictional military system of the United States in the film Olympus Has Fallen
Cerberus, a fictional scientific project in the television series The 100
Cerberus, a fictional dog in British soap opera Coronation Street
Cerberus, a character in the video game Helltaker
Works
Cerberus (film), a science fiction mov
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https://en.wikipedia.org/wiki/Base%20excision%20repair
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Base excision repair (BER) is a cellular mechanism, studied in the fields of biochemistry and genetics, that repairs damaged DNA throughout the cell cycle. It is responsible primarily for removing small, non-helix-distorting base lesions from the genome. The related nucleotide excision repair pathway repairs bulky helix-distorting lesions. BER is important for removing damaged bases that could otherwise cause mutations by mispairing or lead to breaks in DNA during replication. BER is initiated by DNA glycosylases, which recognize and remove specific damaged or inappropriate bases, forming AP sites. These are then cleaved by an AP endonuclease. The resulting single-strand break can then be processed by either short-patch (where a single nucleotide is replaced) or long-patch BER (where 2–10 new nucleotides are synthesized).
Lesions processed by BER
Single bases in DNA can be chemically damaged by a variety of mechanisms, the most common ones being deamination, oxidation, and alkylation. These modifications can affect the ability of the base to hydrogen-bond, resulting in incorrect base-pairing, and, as a consequence, mutations in the DNA. For example, incorporation of adenine across from 8-oxoguanine (right) during DNA replication causes a G:C base pair to be mutated to T:A. Other examples of base lesions repaired by BER include:
Oxidized bases: 8-oxoguanine, 2,6-diamino-4-hydroxy-5-formamidopyrimidine (FapyG, FapyA)
Alkylated bases: 3-methyladenine, 7-methylguanosin
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https://en.wikipedia.org/wiki/Altaf%20Wani
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Altaf A. Wani is retired a professor in the Department of Radiology and the Department of Cellular and Molecular Biology at Ohio State University (OSU). He eas a member of Molecular Carcinogenesis and Chemoprevention program of the James Cancer Hospital and Research Institute. Dr. Wani was the Director of Molecular Carcinogenesis Laboratory and conducts Basic Cancer research in the area of DNA damage and repair.
He is a Graduate Studies Committee member of the Ohio State Biochemistry Program and member of Integrated Biomedical Graduate Program. He served on the Appointments, Tenure and Promotion Committee of the OSU College of Medicine and Public Health. He represents his department at the University Faculty Council and Senate.
Dr. Wani is a member of the American Association for the Advancement of Science (AAAS), American Society of Biochemistry and Molecular Biology, Environmental Mutagen Society and American Society of Photobiology. In 2004 he was inducted as an AAAS Fellow. He serves on the National Institutes of Health (NIH) chartered XNDA study-section and on ad hoc basis on other NIH panels.
References
External links
https://web.archive.org/web/20140715233446/http://www.radiology.osu.edu/10724.cfm
https://archive.today/20140709080540/https://osbp.osu.edu/people/faculty/wani
Ohio State University faculty
People from Srinagar
Living people
Year of birth missing (living people)
Indian radiologists
American physicians of Indian descent
American people of Kashmiri de
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https://en.wikipedia.org/wiki/John%20Cunningham%20McLennan
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Sir John Cunningham McLennan, (October 14, 1867 – October 9, 1935) was a Canadian physicist.
Born in Ingersoll, Ontario, the son of David McLennan and Barbara Cunningham, he was the director of the physics laboratory at the University of Toronto from 1906 until 1932.
McLennan was elected a Fellow of the Royal Society in 1915. McLennan delivered the Guthrie lecture to the Physical Society in 1918. With his graduate student, Gordon Merritt Shrum, he built a helium liquefier at the University of Toronto. They were the second in the world to successfully produce liquid helium in 1923, 15 years after Heike Kammerlingh Onnes. In 1926, he was awarded the Royal Society of Canada's Flavelle Medal and in 1927 a Royal Medal.
He died in 1935 near Abbeville in France on a train from Paris to London of a heart attack. He is buried beside his wife in Stow of Wedale, Scotland.
References
Further reading
University of Toronto biography
John Cunningham McLennan at The Canadian Encyclopedia
John Cunningham McLennan archival papers held at the University of Toronto Archives and Records Management Services
1867 births
1935 deaths
Canadian physicists
Fellows of the Royal Society
Fellows of the Royal Society of Canada
Canadian Knights Commander of the Order of the British Empire
University of Toronto alumni
Academic staff of the University of Toronto
Royal Medal winners
People from Ingersoll, Ontario
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https://en.wikipedia.org/wiki/D.%20Van%20Holliday
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Dale Vance Holliday (May 29, 1940 – February 4, 2010) was an American physicist and acoustician.
Born in Ennis, Texas, Holliday attended the University of Texas at Austin. He graduated with a B.S. and M.A. in Physics and did extensive theoretical and experimental research on the Mössbauer effect. He died in San Diego on February 4, 2010, after a period of illness.
Holliday became one of the first 100 employees of Tracor in 1962 and quickly became Director of Analysis and Applied Research in the Electronic Systems Division. In 1965 Holliday left Austin to develop the Tracor facility in San Diego and began his doctorate in applied physics at the University of California, San Diego.
In San Diego Holliday began his study in acoustics for which he is known. His study of transient flow in natural gas pipelines led to the publication of a textbook which is still used as a standard reference.
In the 1970s Holliday began testing a revolutionary technique for the detection and size measurement of zooplankton in thin layers involving multi-frequency backscattering. The technique developed and after twenty years became the established framework for research in the field.
In the early 1980s Holliday built the first prototype of the Tracor Acoustical Profiling System (TAPS) which has been described as decades ahead of its time by the Acoustical Society of America. TAPS is now the standard instrument for acoustical profiling of plankton in the sea.
Holliday published hundreds of paper
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https://en.wikipedia.org/wiki/Sergey%20Leontiev
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Sergey Fyodorovich Leontiev (, born 9 February 1944 in Leontovka, Podilsk Raion, Odesa Oblast, Ukrainian SSR, Soviet Union) was the Vice President of Transnistria from December 2001 until December 2006.
He studied at the faculty of mathematics and physics of the T. G. Shevchenko University in Tiraspol, Transnistria. He was head of the administrative district of Grigoriopol. He was a deputy of the Supreme Council of Transnistria from 1990 to 2000.
In 2000 he became head of the presidential administration of Transnistria. He was not a candidate in the 2006 election, and hence was replaced by Aleksandr Ivanovich Korolyov.
References
1944 births
Living people
People from Odesa Oblast
Vice presidents of Transnistria
Members of the Supreme Council (Transnistria)
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https://en.wikipedia.org/wiki/Full%20Domain%20Hash
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In cryptography, the Full Domain Hash (FDH) is an RSA-based signature scheme that follows the hash-and-sign paradigm. It is provably secure (i.e., is existentially unforgeable under adaptive chosen-message attacks) in the random oracle model. FDH involves hashing a message using a function whose image size equals the size of the RSA modulus, and then raising the result to the secret RSA exponent.
Exact security of full domain hash
In the random oracle model, if RSA is -secure, then the full domain hash RSA signature scheme is -secure where,
.
For large this reduces to .
This means that if there exists an algorithm that can forge a new FDH signature that runs in time t, computes at most hashes, asks for at most signatures and succeeds with probability , then there must also exist an algorithm that breaks RSA with probability in time .
References
Jean-Sébastien Coron(AF): On the Exact Security of Full Domain Hash. CRYPTO 2000: pp. 229–235 (PDF)
Mihir Bellare, Phillip Rogaway: The Exact Security of Digital Signatures - How to Sign with RSA and Rabin. EUROCRYPT 1996: pp. 399–416 (PDF)
Digital signature schemes
Theory of cryptography
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https://en.wikipedia.org/wiki/LTK
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LTK may refer to the
LTK Commune
Leukocyte receptor tyrosine kinase, in biochemistry, a member of the receptor tyrosine kinase family of cell surface receptors
Bassel Al-Assad International Airport, the airport of Latakia, Syria (IATA code).
Licence to Kill, 1989 James Bond film
LIKEtoKNOW.it, shopping app which became LTK in 2021
Little Kimble railway station, England; National Rail station code LTK
Legends of the Three Kingdoms, a Chinese popular card game based on the Three Kingdoms period of China and the semi-fictional novel Romance of the Three Kingdoms (ROTK).
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https://en.wikipedia.org/wiki/Lou%20Giordano
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Lou Giordano (born c. 1957) is a record producer and recording engineer who co-founded Radiobeat Studios. He worked at Fort Apache Studios when it was located in Boston, and was a partner in the production company Prodco, which had close ties with Fort Apache.
Giordano received a degree in electrical engineering from MIT. He was a sound man for Hüsker Dü through 1988, and later produced Bob Mould's spin off Sugar. Giordano also built effects pedals for Mission of Burma.
He has produced a wide variety of bands, including Sunny Day Real Estate, The Connells, and the Goo Goo Dolls.
Giordano is also well known for having produced Taking Back Sunday’s second album, Where You Want To Be.
References
American record producers
American audio engineers
Year of birth missing (living people)
Living people
MIT School of Engineering alumni
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https://en.wikipedia.org/wiki/Bispectrum
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In mathematics, in the area of statistical analysis, the bispectrum is a statistic used to search for nonlinear interactions.
Definitions
The Fourier transform of the second-order cumulant, i.e., the autocorrelation function, is the traditional power spectrum.
The Fourier transform of C3(t1, t2) (third-order cumulant-generating function) is called the bispectrum or bispectral density.
Calculation
Applying the convolution theorem allows fast calculation of the bispectrum: , where denotes the Fourier transform of the signal, and its conjugate.
Applications
Bispectrum and bicoherence may be applied to the case of non-linear interactions of a continuous spectrum of propagating waves in one dimension.
Bispectral measurements have been carried out for EEG signals monitoring. It was also shown that bispectra characterize differences between families of musical instruments.
In seismology, signals rarely have adequate duration for making sensible bispectral estimates from time averages.
Bispectral analysis describes observations made at two wavelengths. It is often used by scientists to analyze elemental makeup of a planetary atmosphere by analyzing the amount of light reflected and received through various color filters. By combining and removing two filters, much can be gleaned from only two filters. Through modern computerized interpolation, a third virtual filter can be created to recreate true color photographs that, while not particularly useful for scientific analy
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https://en.wikipedia.org/wiki/Bicoherence
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In mathematics and statistical analysis, bicoherence (also known as bispectral coherency) is a squared normalised version of the bispectrum. The bicoherence takes values bounded between 0 and 1, which make it a convenient measure for quantifying the extent of phase coupling in a signal. The prefix bi- in bispectrum and bicoherence refers not to two time series xt, yt but rather to two frequencies of a single signal.
The bispectrum is a statistic used to search for nonlinear interactions. The Fourier transform of the second-order cumulant, i.e., the autocorrelation function, is the traditional power spectrum. The Fourier transform of C3(t1,t2) (third-order cumulant) is called bispectrum or bispectral density. They fall in the category of Higher Order Spectra, or Polyspectra and provide supplementary information to the power spectrum. The third order polyspectrum (bispectrum) is the easiest to compute, and hence the most popular.
The difference with measuring coherence (coherence analysis is an extensively used method to study the correlations in frequency domain, between two simultaneously measured signals) is the need for both input and output measurements by estimating two auto-spectra and one cross spectrum. On the other hand, bicoherence is an auto-quantity, i.e. it can be computed from a single signal. The coherence function provides a quantification of deviations from linearity in the system which lies between the input and output measurement sensors. The bicoherence m
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https://en.wikipedia.org/wiki/Charles-Fran%C3%A7ois%20Dupuis
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Charles François Dupuis (26 October 174229 September 1809) was a French savant, a professor (from 1766) of rhetoric at the Collège de Lisieux, Paris, who studied for the law in his spare time and was received as avocat in 1770. He also ventured into the field of mathematics and served on the committee that developed the French Republican Calendar.
Along with Constantin François Chassebœuf de Volney (1757–1820) Dupuis was known for developing the Christ myth theory, which argued that Christianity was an amalgamation of various ancient mythologies and that Jesus was a mythical character.
Biography
Dupuis was born in Trie-Château (in present-day Oise), the son of a schoolmaster. His precocious talents were recognized by the duc de La Rochefoucauld, who sent him to the College d'Harcourt. Dupuis made such rapid progress that, at the age of twenty-four, he was appointed professor of rhetoric at the college of Lisieux, where he had previously passed as a Licentiate of Theology. In his hours of leisure he studied law, and in 1770 he abandoned the clerical career and became an advocate. Two university discourses which he delivered in Latin were printed, and laid the foundation of his literary fame.
In 1778, he invented a telegraph with which he was able to correspond with his friend Jean-Baptiste Fortin in Bagneux, and must be considered among the first inventors of the telegraph that was perfected by Claude Chappe. The Revolution made it necessary to destroy his machine in orde
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https://en.wikipedia.org/wiki/Leo%20Burt
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Leo Frederick Burt (born April 18, 1948) is an American man indicted in connection with the August 24, 1970 Sterling Hall bombing at the University of Wisconsin–Madison campus, a protest against the Vietnam War. The bombing killed physics researcher Robert Fassnacht and injured several others. Burt was reportedly involved in making and planting the bomb. He has been a fugitive from justice since 1970 and his status and whereabouts are unknown.
Early life and education
Born in Darby, Pennsylvania, Burt grew up in a Catholic family in Havertown, Pennsylvania. He attended St. Denis Parochial School and Monsignor Bonner High School, an all-boys school, where he was an athlete. He enrolled at the University of Wisconsin–Madison, where he was involved in varsity crew. After being cut from the team, he became more active in journalism and student politics, working at the campus newspaper, The Daily Cardinal, with future fellow bomber David Fine.
Burt became radicalized after being beaten by a policeman while covering a protest against the Kent State shootings.
Sterling Hall bombing
The bombing of Sterling Hall on the campus of the University of Wisconsin on August 24, 1970, killed Robert Fassnacht, a postdoctoral physics researcher, and injured three others. It also caused $2.1 million in damage. Burt was reportedly involved in making and planting the bomb and also introduced his fellow bombers David Fine and Karl Armstrong to one another in July 1970.
Life as fugitive and ind
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https://en.wikipedia.org/wiki/Hash%20list
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In computer science, a hash list is typically a list of hashes of the data blocks in a file or set of files. Lists of hashes are used for many different purposes, such as fast table lookup (hash tables) and distributed databases (distributed hash tables).
A hash list is an extension of the concept of hashing an item (for instance, a file). A hash list is a subtree of a Merkle tree.
Root hash
Often, an additional hash of the hash list itself (a top hash, also called root hash or master hash) is used. Before downloading a file on a p2p network, in most cases the top hash is acquired from a trusted source, for instance a friend or a web site that is known to have good recommendations of files to download. When the top hash is available, the hash list can be received from any non-trusted source, like any peer in the p2p network. Then the received hash list is checked against the trusted top hash, and if the hash list is damaged or fake, another hash list from another source will be tried until the program finds one that matches the top hash.
In some systems (for example, BitTorrent), instead of a top hash the whole hash list is available on a web site in a small file. Such a "torrent file" contains a description, file names, a hash list and some additional data.
Applications
Hash lists can be used to protect any kind of data stored, handled and transferred in and between computers. An important use of hash lists is to make sure that data blocks received from other peers in a
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https://en.wikipedia.org/wiki/Merkle%20tree
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In cryptography and computer science, a hash tree or Merkle tree is a tree in which every "leaf" (node) is labelled with the cryptographic hash of a data block, and every node that is not a leaf (called a branch, inner node, or inode) is labelled with the cryptographic hash of the labels of its child nodes. A hash tree allows efficient and secure verification of the contents of a large data structure. A hash tree is a generalization of a hash list and a hash chain.
Demonstrating that a leaf node is a part of a given binary hash tree requires computing a number of hashes proportional to the logarithm of the number of leaf nodes in the tree. Conversely, in a hash list, the number is proportional to the number of leaf nodes itself. A Merkle tree is therefore an efficient example of a cryptographic commitment scheme, in which the root of the tree is seen as a commitment and leaf nodes may be revealed and proven to be part of the original commitment.
The concept of a hash tree is named after Ralph Merkle, who patented it in 1979.
Uses
Hash trees can be used to verify any kind of data stored, handled and transferred in and between computers. They can help ensure that data blocks received from other peers in a peer-to-peer network are received undamaged and unaltered, and even to check that the other peers do not lie and send fake blocks.
Hash trees are used in hash-based cryptography. Hash trees are also used in the InterPlanetary File System (IPFS), Btrfs and ZFS file systems
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https://en.wikipedia.org/wiki/Franz%20Wittmann%20%28physicist%29
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Franz Wittman (16 January 1860 in Hódmezővásárhely – 1932 in Budapest) was a Hungarian electrical engineer and physicist. He was educated at the University of Budapest and continued his studies in Vienna, Berlin, Paris, Frankfurt-am-Main, Darmstadt and Hanover. In 1892, he was appointed professor of physics at the polytechnic in Budapest. Five years later, he became a member of the royal patent bureau and secretary of the board of examiners for teachers in intermediate schools.
Wittmann's works, which have made him the leading Hungarian authority on electrotechnics, include the following:
"Az Inductiv Taszításról" (on inductive repulsion)
"Periodikus Áramok Optikai Vizsgálata" (optical tests of periodical currents)
"Budapest Villamvilágításáról" (electric lighting of Budapest)
"Az Erős Villamáramok Technikája" (technics of strong electric currents)
"A Leydeni Batteriák és Induktoriumok Áramának Vizsgálata és Objektív Előállítása" (objective production of currents from Leyden jars and inductors);
"Kondensatorok Áramának Vizsgálata és Objectív Előállítása" (test and objective production of currents from condensers);
"Akusztikai Kísérletek" (acoustic experiments)
In addition to these works, Wittmann has published numerous articles on the technical uses of electricity and heat.
References
1860 births
1932 deaths
19th-century Hungarian physicists
20th-century Hungarian physicists
Hungarian electrical engineers
Hungarian Jews
Budapest University alumni
Hungarian expatriates
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https://en.wikipedia.org/wiki/Acoustic%20metric
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In acoustics and fluid dynamics, an acoustic metric (also known as a sonic metric) is a metric that describes the signal-carrying properties of a given particulate medium.
(Generally, in mathematical physics, a metric describes the arrangement of relative distances within a surface or volume, usually measured by signals passing through the region – essentially describing the intrinsic geometry of the region.)
A simple fluid example
For simplicity, we will assume that the underlying background geometry is Euclidean, and that this space is filled with an isotropic inviscid fluid at zero temperature (e.g. a superfluid). This fluid is described by a density field ρ and a velocity field . The speed of sound at any given point depends upon the compressibility which in turn depends upon the density at that point. It requires much work to compress anything more into an already compacted space. This can be specified by the "speed of sound field" c. Now, the combination of both isotropy and Galilean covariance tells us that the permissible velocities of the sound waves at a given point x, has to satisfy
This restriction can also arise if we imagine that sound is like "light" moving through a spacetime described by an effective metric tensor called the acoustic metric.
The acoustic metric is
"Light" moving with a velocity of (not the 4-velocity) has to satisfy
If
where α is some conformal factor which is yet to be determined (see Weyl rescaling), we get the desired velocity re
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https://en.wikipedia.org/wiki/Max%20Weiss
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Miksa (Max) Weisz (21 July 1857 – 14 March 1927) was an Austrian chess player born in the Kingdom of Hungary.
Weiss was born in Sereď. Moving to Vienna, he studied mathematics and physics at the university, and later taught those subjects.
Weiss learned to play chess at age 12, and his strength increased steadily throughout the 1880s.
1880, Graz, tied with Adolf Schwarz and Johannes von Minckwitz for first prize.
1882, Vienna, tenth, won two games from Johann Zukertort, and drew with Wilhelm Steinitz.
1883, Nuremberg, tenth.
1885, Hamburg, tied with Berthold Englisch and Siegbert Tarrasch for second prize.
1887, Frankfort-on-the-Main, divided second and third prizes with Joseph Henry Blackburne.
1888, Bradford, tied with Blackburne for sixth prize.
1889, New York, (the sixth American Chess Congress), scored +24−4=10 to tie with Mikhail Chigorin for first prize, ahead of Isidor Gunsberg and Blackburne.
1889, Breslau, third prize.
1890, Vienna, first prize, ahead of Johann Bauer and Englisch.
The New York 1889 tournament was organized to find a challenger for the World Chess Championship, but neither Chigorin (who had already lost a championship match) nor Weiss pursued a title match with Steinitz.
In fact, having become one of the top players in the world, Weiss quit international chess after this tournament, though he did play a few Viennese events.
In 1895 he defeated Georg Marco in a match, +5 −1 =1, and he tied for first in the 1895–6 winter tournament with Carl Schlech
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https://en.wikipedia.org/wiki/Complex%20differential%20form
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In mathematics, a complex differential form is a differential form on a manifold (usually a complex manifold) which is permitted to have complex coefficients.
Complex forms have broad applications in differential geometry. On complex manifolds, they are fundamental and serve as the basis for much of algebraic geometry, Kähler geometry, and Hodge theory. Over non-complex manifolds, they also play a role in the study of almost complex structures, the theory of spinors, and CR structures.
Typically, complex forms are considered because of some desirable decomposition that the forms admit. On a complex manifold, for instance, any complex k-form can be decomposed uniquely into a sum of so-called (p, q)-forms: roughly, wedges of p differentials of the holomorphic coordinates with q differentials of their complex conjugates. The ensemble of (p, q)-forms becomes the primitive object of study, and determines a finer geometrical structure on the manifold than the k-forms. Even finer structures exist, for example, in cases where Hodge theory applies.
Differential forms on a complex manifold
Suppose that M is a complex manifold of complex dimension n. Then there is a local coordinate system consisting of n complex-valued functions z1, ..., zn such that the coordinate transitions from one patch to another are holomorphic functions of these variables. The space of complex forms carries a rich structure, depending fundamentally on the fact that these transition functions are holo
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https://en.wikipedia.org/wiki/Alternating%20algebra
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In mathematics, an alternating algebra is a -graded algebra for which for all nonzero homogeneous elements and (i.e. it is an anticommutative algebra) and has the further property that for every homogeneous element of odd degree.
Examples
The differential forms on a differentiable manifold form an alternating algebra.
The exterior algebra is an alternating algebra.
The cohomology ring of a topological space is an alternating algebra.
Properties
The algebra formed as the direct sum of the homogeneous subspaces of even degree of an anticommutative algebra is a subalgebra contained in the centre of , and is thus commutative.
An anticommutative algebra over a (commutative) base ring in which 2 is not a zero divisor is alternating.
See also
Alternating multilinear map
Exterior algebra
Graded-symmetric algebra
References
Algebraic geometry
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https://en.wikipedia.org/wiki/OM%20Group
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OM Group Incorporated is a metal-based chemistry firm based in Cleveland, Ohio, United States. It is a provider of speciality chemicals, advanced materials and technologies. The company was listed on the New York Stock Exchange prior to being privatized by Apollo Global Management in June 2015.
Overview of Operations
OM Group employs approximately 6,000 people and has locations in Canada, China, D.R. Congo, France, Finland, Germany, India, Japan, Malaysia, Singapore, Taiwan, the United Kingdom and the United States.
OMG has six business units:
Advanced Organics
Advanced Materials
Electronic Chemicals
Compugraphics
Ultra Pure Chemicals
Battery Technologies
Of these six units, its three main business platforms are: magnetic technologies, battery technologies and speciality chemicals.
OM Group supplies more than 4,000 customers, serving more than 50 industries worldwide, including automotive systems, electronic devices, aerospace, industrial and renewable energy.
History
The roots of the company date back to the 1940s when the company's predecessor Mooney Chemical Company was founded in 1946 in Cleveland by namesake James Mooney and his partner Carl A. Reusser. Forging strong ties with copper and nickel miners in Zaire and Zambia, Mooney quickly became key supplier of the metals, helping maintain some of the highest levels of productivity in the cobalt specialty-chemicals industry. In the mid-1990s, for example, OM Group's sales per employee were more than double the
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https://en.wikipedia.org/wiki/List%20of%20logic%20symbols
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In logic, a set of symbols is commonly used to express logical representation. The following table lists many common symbols, together with their name, how they should be read out loud, and the related field of mathematics. Additionally, the subsequent columns contains an informal explanation, a short example, the Unicode location, the name for use in HTML documents, and the LaTeX symbol.
Basic logic symbols
Advanced and rarely used logical symbols
These symbols are sorted by their Unicode value:
Usage in various countries
Poland
in Poland, the universal quantifier is sometimes written ∧, and the existential quantifier as ∨. The same applies for Germany.
Japan
The ⇒ symbol is often used in text to mean "result" or "conclusion", as in "We examined whether to sell the product ⇒ We will not sell it". Also, the → symbol is often used to denote "changed to", as in the sentence "The interest rate changed. March 20% → April 21%".
See also
Józef Maria Bocheński
List of notation used in Principia Mathematica
List of mathematical symbols
Logic alphabet, a suggested set of logical symbols
Logical connective
Mathematical operators and symbols in Unicode
Non-logical symbol
Polish notation
Truth function
Truth table
Wikipedia:WikiProject Logic/Standards for notation
References
Further reading
Józef Maria Bocheński (1959), A Précis of Mathematical Logic, trans., Otto Bird, from the French and German editions, Dordrecht, South Holland: D. Reidel.
External links
N
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https://en.wikipedia.org/wiki/Simone%20Niggli-Luder
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Simone Niggli-Luder (born 9 January 1978) is a Swiss orienteering athlete who has twice won (in 2003 and 2005) all four women's competitions at the world championships. She is widely seen as one of the greatest orienteers of all time.
Personal life
Born as Simone Luder, she grew up in Burgdorf in the Canton of Bern. She studied biology at the University of Bern, where she graduated in 2003. That same year, she married Matthias Niggli, also a Swiss orienteering athlete. They currently live in Münsingen near Bern and in Ulricehamn, Sweden.
Orienteering achievements
She began competing in orienteering early on, joining the Swiss club OLV Hindelbank; at the age of ten, she participated in her first competition. Since then, her palmarès has been impressive: she won a gold medal at the junior world championships in 1997, has been 20 times Swiss champion, won the Finnish championships once and the Swedish championships nine times, has won the world cup five times, and won seven gold medals at European championships and a total of 23 gold medals at world championships.
In 2003, she won all four women's competitions of the world championships held at Rapperswil in Switzerland (sprint, middle, and long distance, and— together with Birgitte Wolf and Vroni König-Salmi— the relay). She managed to repeat this extraordinary feat two years later at the world championships in Aichi, Japan.
At the European Championships in 2006 in Otepää, Estonia, she won gold in the sprint and long di
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https://en.wikipedia.org/wiki/Supermatrix
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In mathematics and theoretical physics, a supermatrix is a Z2-graded analog of an ordinary matrix. Specifically, a supermatrix is a 2×2 block matrix with entries in a superalgebra (or superring). The most important examples are those with entries in a commutative superalgebra (such as a Grassmann algebra) or an ordinary field (thought of as a purely even commutative superalgebra).
Supermatrices arise in the study of super linear algebra where they appear as the coordinate representations of a linear transformations between finite-dimensional super vector spaces or free supermodules. They have important applications in the field of supersymmetry.
Definitions and notation
Let R be a fixed superalgebra (assumed to be unital and associative). Often one requires R be supercommutative as well (for essentially the same reasons as in the ungraded case).
Let p, q, r, and s be nonnegative integers. A supermatrix of dimension (r|s)×(p|q) is a matrix with entries in R that is partitioned into a 2×2 block structure
with r+s total rows and p+q total columns (so that the submatrix X00 has dimensions r×p and X11 has dimensions s×q). An ordinary (ungraded) matrix can be thought of as a supermatrix for which q and s are both zero.
A square supermatrix is one for which (r|s) = (p|q). This means that not only is the unpartitioned matrix X square, but the diagonal blocks X00 and X11 are as well.
An even supermatrix is one for which the diagonal blocks (X00 and X11) consist solely of even e
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https://en.wikipedia.org/wiki/David%20Riesman
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David Riesman (September 22, 1909 – May 10, 2002) was an American sociologist, educator, and best-selling commentator on American society.
Career
Born to a wealthy German Jewish family, Riesman attended Harvard College, where he graduated in 1931 with a degree in biochemistry. He attended Harvard Law School, where he was a member of the Harvard Law Review. Riesman clerked for Supreme Court Justice Louis Brandeis between 1935 and 1936. He also taught at what is now the University at Buffalo Law School and at the University of Chicago.
He worked for Sperry Gyroscope company during the war. After a fellowship at Yale to write The Lonely Crowd, he returned to Chicago. In 1958, he became a university professor at Harvard. He was a member of the American Academy of Arts and Sciences (1955) and the American Philosophical Society (1974). Intellectually he was influenced most by Erich Fromm, as well as Carl Friedrich, Hannah Arendt, Leo Löwenthal, Robert K. Merton, Paul Lazarsfeld, Paul Goodman, Martha Wolfenstein, and Nathan Leites. He widely referenced the works of Thorstein Veblen, Max Weber, and Sigmund Freud.
The Lonely Crowd
Daniel Horowitz says The Lonely Crowd: A Study of the Changing American Character, in 1950
quickly became the nation’s most influential and widely read mid-century work of social and cultural criticism. It catapulted its author to the cover of Time magazine in 1954, making Riesman the first social scientist so honored.... Riesman offered a nuanced and c
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https://en.wikipedia.org/wiki/David%20Mercer%20%28playwright%29
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David Mercer (27 June 1928 – 8 August 1980) was an English dramatist.
Mercer, born in Wakefield, Yorkshire, England, worked as a laboratory technician and in the Merchant Navy before attending university. After studying chemistry, he switched to art but eventually turned to writing. Mercer's television work for the BBC was often made in collaboration with director Don Taylor. His first stage play, Ride a Cock Horse, starred Peter O'Toole. The Royal Shakespeare Company premiered many of his works, and Mercer also wrote the screenplay for the Alain Resnais film Providence, which won a César Award. A long-term heavy drinker, Mercer died in 1980 after suffering a heart attack in Haifa, Israel.
Early life
Mercer was born in Wakefield, Yorkshire, England, the son of an engine driver while his mother had been a domestic servant. Both of his grandfathers had been miners. After failing to gain entry to the local grammar school, Mercer left school at 14, worked as a laboratory technician and in the Merchant Navy before attending university. After attending courses at Wakefield Technical College he matriculated at University College, Durham to study chemistry, but eventually grew bored of this and switched to studying art at King's College Newcastle – which was then part of Durham University. Just after graduation he married Jitke Sigmund, a Czechoslovakian refugee who was studying Economics at King's. Her father had been killed by the Gestapo. With his wife, he spent a year in Pari
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https://en.wikipedia.org/wiki/John%20H.%20Gillespie
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John H. Gillespie is an evolutionary biologist interested in theoretical population genetics and molecular evolution. In molecular evolution, he emphasized the importance of advantageous mutations and balancing selection. For that reason, Gillespie is well known for his selectionist stance in the neutralist-selectionist debate. He is widely considered the main proponent of natural selection in molecular evolution. He had a well-known feud with the father of the neutral theory of molecular evolution, Motoo Kimura, initiated by a 1984 review in Science of Kimura's book in which Gillespie criticized Kimura for "using the book as a vehicle to establish for himself a niche in the history of science." Gillespie had only four Ph.D. students during his career: Richard Hudson, James N. McNair, David J. Cutler, and Andrew Kern, but mentored many more. Gillespie was a professor in the College of Biological Sciences at the University of California, Davis until his retirement in 2005.
References
Blum, D. (1992). "Scientists in Open War over "Neutral Theory" of Genetics". Sacramento Bee, March 16, p.A1.
Evolutionary biologists
Population geneticists
University of California, Davis faculty
Living people
Year of birth missing (living people)
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https://en.wikipedia.org/wiki/Alternate%20reality
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Alternate reality often refers to parallel universes in fiction, a self-contained separate world, universe or reality coexisting with the real world, which is used as a recurring plot point or setting used in fantasy and science fiction.
Alternate reality may also refer to:
Science
The many-worlds interpretation of quantum mechanics, which implies the existence of parallel universes
Multiverse, a group of multiple universes
Arts and media
Alternate history, a genre of fiction consisting of stories that are set in worlds in which historical events unfold differently from the real world
Alternate universe (fan fiction), fiction by fan authors that deliberately alters facts of the canonical universe they are writing about
Literature
Alternate Realities (Cherryh), a 2000 anthology of science fiction by C. J. Cherryh
Games and video games
Alternate Reality (series), a role-playing video game series started in 1985 with two of several intended games released
Alternate reality game, a type of cross-media game
Virtual reality, simulated reality
Other uses
A euphemism for "psychedelic experience"
See also
Metaverse, a collective virtual shared space
Parallel universe (disambiguation)
Separate reality (disambiguation)
Megaverse (disambiguation)
Multiverse (disambiguation)
Omniverse (disambiguation)
AR (disambiguation)
Augmented reality
Alternate facts
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https://en.wikipedia.org/wiki/Von%20Richter%20reaction
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The von Richter reaction, also named von Richter rearrangement, is a name reaction in the organic chemistry. It is named after Victor von Richter, who discovered this reaction in year 1871. It is the reaction of aromatic nitro compounds with potassium cyanide in aqueous ethanol to give the product of cine substitution (ring substitution resulting in the entering group positioned adjacent to the previous location of the leaving group) by a carboxyl group. Although it is not generally synthetically useful due to the low chemical yield and formation of numerous side products, its mechanism was of considerable interest, eluding chemists for almost 100 years before the currently accepted one was proposed.
General reaction scheme
The reaction below shows the classic example of the conversion of p-bromonitrobenzene into m-bromobenzoic acid.
The reaction is a type of nucleophilic aromatic substitution. Besides the bromo derivative, chlorine- and iodine-substituted nitroarenes, as well as more highly substituted derivatives, could also be used as substrates of this reaction. However, yields are generally poor to moderate, with reported percentage yields ranging from 1% to 50%.
Reaction mechanism
Several reasonable mechanisms were proposed and refuted by mechanistic data before the currently accepted one, shown below, was proposed in 1960 by Rosenblum on the basis of 15N labeling experiments.
First, the cyanide attacks the carbon ortho to the nitro group. This is followed by rin
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https://en.wikipedia.org/wiki/Yvonne%20John%20Lewis
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Yvonne John Lewis (occasionally spelled Yvonne John-Lewis) is a British female lead and backing singer. She is currently teaching mathematics at a secondary school in North London.
Hailing from London, she was discovered by Osmond Wright, better known by his stage name "Mozez" and a singer for British downtempo group Zero 7.
John Lewis first featured as a lead vocalist on Zero 7's albums, and has gone on to provide lead vocals for and been featured on recordings by artists including as Basement Jaxx, Sia, Stella Browne, Narcotic Thrust and Rollercone. She is well known as the featured singer on Narcotic Thrust's number one Billboard Hot Dance Music/Club Play hit from 2002, Safe from Harm.
John Lewis has worked as a backing vocalist for artists like Bryan Ferry, Blue, Enrique Iglesias, James Fargas, Westlife and Atomic Kitten. She also provided the vocal sample in Simon Webbe's track, "No Worries". She toured with Roxy Music in 2004.
See also
List of number-one dance hits (United States)
List of artists who reached number one on the US Dance chart
References
External links
Year of birth missing (living people)
Living people
21st-century Black British women singers
English house musicians
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https://en.wikipedia.org/wiki/Kan%20extension
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Kan extensions are universal constructs in category theory, a branch of mathematics. They are closely related to adjoints, but are also related to limits and ends. They are named after Daniel M. Kan, who constructed certain (Kan) extensions using limits in 1960.
An early use of (what is now known as) a Kan extension from 1956 was in homological algebra to compute derived functors.
In Categories for the Working Mathematician Saunders Mac Lane titled a section "All Concepts Are Kan Extensions", and went on to write that
The notion of Kan extensions subsumes all the other fundamental concepts of category theory.
Kan extensions generalize the notion of extending a function defined on a subset to a function defined on the whole set. The definition, not surprisingly, is at a high level of abstraction. When specialised to posets, it becomes a relatively familiar type of question on constrained optimization.
Definition
A Kan extension proceeds from the data of three categories
and two functors
,
and comes in two varieties: the "left" Kan extension and the "right" Kan extension of along .
The right Kan extension amounts to finding the dashed arrow and the natural transformation in the following diagram:
Formally, the right Kan extension of along consists of a functor and a natural transformation that is couniversal with respect to the specification, in the sense that for any functor and natural transformation , a unique natural transformation is defined and fits in
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https://en.wikipedia.org/wiki/Peter%20A.%20Sturrock
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Peter Andrew Sturrock (born 20 March 1924) is a British scientist. An emeritus professor of applied physics at Stanford University, much of Sturrock's career has been devoted to astrophysics, plasma physics, and solar physics, but Sturrock is interested in other fields, including ufology, scientific inference, the history of science, and the philosophy of science. Sturrock has been awarded many prizes and honors, and has written or co-authored many scientific papers and textbooks.
Biography
Sturrock began his education studying mathematics at Cambridge University in 1942. During and after World War 2, Sturrock postponed his Cambridge studies in order to help develop radar systems at the Telecommunications Research Establishment, now the Royal Radar Establishment.
After the war, Sturrock resumed his education, and was awarded a scholarship at St John's College in 1947, followed by the University Rayleigh Prize for mathematics in 1949. Sturrock was elected to a fellowship at St John's in 1952. He then pursued work on electron physics at the Cavendish Laboratory, followed by stints at Cambridge, the National Bureau of Standards, and the École Normale Supérieure at the University of Paris.
In 1951, Sturrock earned a Ph.D. in astrophysics. In the 1950s Sturrock researched nuclear physics at the Atomic Energy Research Establishment; plasma physics at St. Johns' College, Cambridge; microwave tubes at Stanford University; accelerator physics at the European Organization for Nuclea
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https://en.wikipedia.org/wiki/Phosphorus%20oxoacid
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In chemistry, phosphorus oxoacid (or phosphorus acid) is a generic name for any acid whose molecule consists of atoms of phosphorus, oxygen, and hydrogen. There is a potentially infinite number of such compounds. Some of them are unstable and have not been isolated, but the derived anions and organic groups are present in stable salts and esters. The most important ones—in biology, geology, industry, and chemical research—are the phosphoric acids, whose esters and salts are the phosphates.
In general, any hydrogen atom bonded to an oxygen atom is acidic, meaning that the –OH group can lose a proton leaving a negatively charged – group and thus turning the acid into a phosphorus oxoanion. Each additional proton lost has an associated acid dissociation constant Ka1, Ka2 Ka3, ..., often expressed by its cologarithm (pKa1, pKa2, pKa3, ...). Hydrogen atoms bonded directly to phosphorus are generally not acidic.
Classification
The phosphorus oxoacids can be classified by the oxidation state(s) of the phosphorus atom(s), which may vary from +1 to +5. The oxygen atoms are usually in oxidation state -2, but may be in state -1 if the molecule includes peroxide groups.
Oxidation state +1
Hypophosphorous acid (or phosphinic acid), (or ), a monoprotic acid (meaning that only one of the hydrogen atoms is acidic). Its salts and esters are called hypophosphites or phosphinates.
Oxidation state +3
Phosphorous acid (or phosphonic acid), (or ), a diprotic acid (with only two ac
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https://en.wikipedia.org/wiki/Banach%20manifold
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In mathematics, a Banach manifold is a manifold modeled on Banach spaces. Thus it is a topological space in which each point has a neighbourhood homeomorphic to an open set in a Banach space (a more involved and formal definition is given below). Banach manifolds are one possibility of extending manifolds to infinite dimensions.
A further generalisation is to Fréchet manifolds, replacing Banach spaces by Fréchet spaces. On the other hand, a Hilbert manifold is a special case of a Banach manifold in which the manifold is locally modeled on Hilbert spaces.
Definition
Let be a set. An atlas of class on is a collection of pairs (called charts) such that
each is a subset of and the union of the is the whole of ;
each is a bijection from onto an open subset of some Banach space and for any indices is open in
the crossover map is an -times continuously differentiable function for every that is, the th Fréchet derivative exists and is a continuous function with respect to the -norm topology on subsets of and the operator norm topology on
One can then show that there is a unique topology on such that each is open and each is a homeomorphism. Very often, this topological space is assumed to be a Hausdorff space, but this is not necessary from the point of view of the formal definition.
If all the Banach spaces are equal to the same space the atlas is called an -atlas. However, it is not a priori necessary that the Banach spaces be the same space, or
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https://en.wikipedia.org/wiki/Hilbert%20manifold
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In mathematics, a Hilbert manifold is a manifold modeled on Hilbert spaces. Thus it is a separable Hausdorff space in which each point has a neighbourhood homeomorphic to an infinite dimensional Hilbert space. The concept of a Hilbert manifold provides a possibility of extending the theory of manifolds to infinite-dimensional setting. Analogously to the finite-dimensional situation, one can define a differentiable Hilbert manifold by considering a maximal atlas in which the transition maps are differentiable.
Properties
Many basic constructions of the manifold theory, such as the tangent space of a manifold and a tubular neighbourhood of a submanifold (of finite codimension) carry over from the finite dimensional situation to the Hilbert setting with little change. However, in statements involving maps between manifolds, one often has to restrict consideration to Fredholm maps, that is, maps whose differential at every point is Fredholm. The reason for this is that Sard's lemma holds for Fredholm maps, but not in general. Notwithstanding this difference, Hilbert manifolds have several very nice properties.
Kuiper's theorem: If is a compact topological space or has the homotopy type of a CW complex then every (real or complex) Hilbert space bundle over is trivial. In particular, every Hilbert manifold is parallelizable.
Every smooth Hilbert manifold can be smoothly embedded onto an open subset of the model Hilbert space.
Every homotopy equivalence between two Hilbert
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https://en.wikipedia.org/wiki/John%20Gribbin
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John R. Gribbin (born 19 March 1946) is a British science writer, an astrophysicist, and a visiting fellow in astronomy at the University of Sussex. His writings include quantum physics, human evolution, climate change, global warming, the origins of the universe, and biographies of famous scientists. He also writes science fiction.
Biography
John Gribbin graduated with his bachelor's degree in physics from the University of Sussex in 1966. Gribbin then earned his Master of Science (MSc) degree in astronomy in 1967, also from the Univ. of Sussex, and he earned his PhD in astrophysics from the University of Cambridge (1971).
In 1968, Gribbin worked as one of Fred Hoyle's research students at the Institute of Theoretical Astronomy, and wrote a number of stories for New Scientist about the Institute's research and what were eventually discovered to be pulsars.
In 1974, Gribbin, along with Stephen Plagemann, published a book titled The Jupiter Effect, which predicted that the alignment of the planets in a quadrant on one side of the Sun on 10 March 1982 would cause gravitational effects that would trigger earthquakes in the San Andreas Fault, possibly wiping out Los Angeles and its suburbs.
Gribbin distanced himself from The Jupiter Effect in the 17 July 1980, issue of New Scientist magazine, stating that he had been "too clever by half".
In February 1982, he and Plagemann published The Jupiter Effect Reconsidered, claiming that the 1980 Mount St. Helens eruption proved the
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https://en.wikipedia.org/wiki/CertCo
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CertCo, Inc., was a financial cryptography startup spun out of Bankers Trust in the 1990s. The company pioneered a risk management approach to cryptographic services. It had offices in New York City and Cambridge, Massachusetts. It offered three main public key infrastructure (PKI) based products: an Identity Warranty system (tracking and insuring reliance on identity assertions in financial transactions); an electronic payment system (internally known as Acquire); and an Online Certificate Status Protocol (OCSP) responder for validating X.509 public key certificates. It went out of business in Spring 2002 never having found a wide market for its products despite filing a number of patents and developing new technology.
History
Early history
CertCo was founded in March 1994 by Frank Sudia and Peter Freund as an internal bank department known as BT Electronic Commerce (BTEC). It spun out in November 1996 as CertCo with a number of outside strategic and financial investors in a transaction managed by Goldman Sachs.
Some of its better known early employees included Rich Ankney, Ed Appel, Alan Asay, Ernest Brickell, David Kravitz (inventor of the Digital Signature Algorithm), Yair Frankel, Dan Geer, C.T. Montgomery, Jay Simmons, Nanette Di Tosto, Paul Turner, Mark Jefferson and Moti Yung.
Early on it licensed the "Fair Cryptosystem" key escrow patents of MIT Professor Silvio Micali and announced plans to implement a "Commercial Key Escrow System". Thereafter the policy clim
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https://en.wikipedia.org/wiki/The%20Quarterly%20Review%20of%20Biology
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The Quarterly Review of Biology is a peer-reviewed scientific journal covering all aspects of biology. It was established in 1926 by Raymond Pearl. In the 1960s it was purchased by the Stony Brook Foundation when the editor H. Bentley Glass became academic vice president of Stony Brook University. The editor-in-chief is Daniel E. Dykhuizen (Stony Brook University). It is currently published by the University of Chicago Press.
Aims and scope
The journal publishes review articles. Beyond the core biological sciences, the journal also covers related areas, including policy studies and the history and philosophy of science. There is also a book review section.
Abstracting and indexing
The journal is abstracted and indexed in Biological Abstracts, BIOSIS Previews, and the Science Citation Index.
References
External links
Biology journals
University of Chicago Press academic journals
Academic journals established in 1926
Quarterly journals
English-language journals
Review journals
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https://en.wikipedia.org/wiki/J.%20Playfair%20McMurrich
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James Playfair McMurrich, (October 16, 1859 – February 9, 1939) was a Canadian zoologist and academic.
Born in Toronto, the son of John McMurrich, McMurrich received a M.A. from the University of Toronto in 1881 and a Ph.D. from Johns Hopkins University in 1885.
From 1881 to 1884, he was a Professor of biology and horticulture at Ontario Agricultural College in the University of Guelph. From 1892 to 1894, he taught at the University of Cincinnati. He was a Professor of Anatomy in homoeopathic department of the University of Michigan. From 1907 to 1930, he was Professor of anatomy at the University of Toronto.
From 1922 to 1923, he was the president of the Royal Society of Canada. In 1922, he was the president of the American Association for the Advancement of Science. In 1933, he was the president of the History of Science Society. In 1939, he was awarded the Royal Society of Canada's Flavelle Medal.
In 1882, he married Katie Moodie Vickers.
Selected bibliography
A text-book of invertebrate morphology (1894)
Leonardo da Vinci: The Anatomist (1930)
References
External links
James Playfair McMurrich and McMurrich Family archival papers held at the University of Toronto Archives and Records Management Services
Canadian zoologists
1859 births
1939 deaths
Fellows of the Royal Society of Canada
University of Toronto alumni
University of Michigan faculty
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https://en.wikipedia.org/wiki/QRB
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QRB may refer to:
Qualitätssicherungssystem Recycling Baustoffe
The Quarterly Review of Biology
Queenstown Road railway station has National Rail code QRB
QRB is Q code for "What is your distance?"
Qué Rica Bieja
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https://en.wikipedia.org/wiki/H.%20E.%20T.%20Haultain
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Herbert Edward Terrick Haultain (9 August 1869 – 19 September 1961) was a Canadian engineer and inventor.
He was born in Brighton, England and died in Toronto, Ontario. He graduated from the University of Toronto with a degree in civil engineering from the School of Practical Science (now the Faculty of Applied Science and Engineering) in 1889. He was largely responsible for the creation of the Ritual of the Calling of an Engineer administered to many Canadian engineering students, where they receive the Iron Ring. The Haultain building at the University of Toronto is named for him and he is an inductee of the Canadian Mining Hall of Fame.
In the 1920s 20% to 30% of the Canadian graduating classes in engineering were emigrating to the United States. In 1927 Professor Haultain and Robert A. Bryce, president of Macassa Mines and a noted mining engineer, co-founded the Technical Service Council, a non-profit, industry-sponsored organization. Its aim was to retain engineers for Canada by operating a placement service for them. In 1971, the Council's executive search arm, Bryce, Haultain & Associates, was named after them. He died in 1961 and was buried in Little Lake Cemetery in Peterborough, Ontario.
External links
Note about Haultain Canadian Mining Hall of Fame
Archival papers of Herbert Edward Terrick Haultain and the Ritual of the Calling of an Engineer are held at the University of Toronto Archives and Records Management Services
1869 births
1961 deaths
Canad
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https://en.wikipedia.org/wiki/Triiodide
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In chemistry, triiodide usually refers to the triiodide ion, . This anion, one of the polyhalogen ions, is composed of three iodine atoms. It is formed by combining aqueous solutions of iodide salts and iodine. Some salts of the anion have been isolated, including thallium(I) triiodide (Tl+[I3]−) and ammonium triiodide ([NH4]+[I3]−). Triiodide is observed to be a red colour in solution.
Nomenclature
Other chemical compounds with "triiodide" in their name may contain three iodide centers that are not bonded to each other as the triiodide ion, but exist instead as separate iodine atoms or iodide ions. Examples include nitrogen triiodide (NI3) and phosphorus triiodide (PI3), where individual iodine atoms are covalently bonded to a central atom. As some cations have the theoretical possibility to form compounds with both triiodide and iodide ions, such as ammonium, compounds containing iodide anions in a 3:1 stoichiometric ratio should only be referred to as triiodides in cases where the triiodide anion is present. It may also be helpful to indicate the oxidation number of a metal cation, where appropriate. For example, the covalent molecule gallium triiodide (Ga2I6) is better referred to as gallium(III) iodide to emphasise that it is iodide anions that are present, and not triiodide.
Preparation
The following exergonic equilibrium gives rise to the triiodide ion:
I2 + I− ⇌
In this reaction, iodide is viewed as a Lewis base, and the iodine is a Lewis acid. The process is ana
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https://en.wikipedia.org/wiki/Murray%20S.%20Blum
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Murray Sheldon Blum (19 July 1929 - 22 March 2015) was an American entomologist and a researcher in the field of chemical ecology.
Born in 1929 in Philadelphia, Pennsylvania, Blum grew up in that city and in Chicago. He earned a BSc in Biology and his Ph.D. in entomology from the University of Illinois in 1955. After serving in the U.S. Army during the Korean War, he joined the faculty of Louisiana State University in 1957. In the 1960s he moved to the University of Georgia, where he spent three decades as a research professor before his retirement. The Entomological Society of America named him as outstanding scientist of the year in 1978, and in 1989 he received the International Society of Chemical Ecology Medal for outstanding scientific contributions.
Blum concentrated much of his research in the area of chemical ecology, and is well-recognized as an expert on pheromones. His subjects of interest also included the eastern lubber grasshopper (Romalea microptera) and imported fire ants as the latter species (Solenopsis invicta) spread through the southern United States. Blum's entomology associates and close friends include noted apiologist Stephen Taber III.
Blum died in 2015 at the age of 85. His daughter Deborah Blum is a Pulitzer Prize-winning journalist and author.
Publications
A past winner of the Lamar Dodd Award for excellence in research, he was the author of many scholarly publications, including the book Chemical Defenses of Arthropods.
Blum, Murray S.
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https://en.wikipedia.org/wiki/Pseudomonad
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Pseudomonad may refer to:
Biology
a member of:
Pseudomonadaceae, the family.
Pseudomonas, the genus.
Mathematics
Pseudomonad (Category Theory), a generalisation of a monad on a category.
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https://en.wikipedia.org/wiki/Tak%20Wah%20Mak
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Tak Wah Mak, (; born October 4, 1946, in China) is a Canadian medical researcher, geneticist, oncologist, and biochemist. He first became widely known for his discovery of the T-cell receptor in 1983 and pioneering work in the genetics of immunology. In 1995, Mak published a landmark paper on the discovery of the function of the immune checkpoint protein CTLA-4, thus opening the path for immunotherapy/checkpoint inhibitors as a means of cancer treatment. Mak is also the founder of Agios Pharmaceuticals, whose lead compound, IDHIFA®, was approved by the FDA for acute myeloid leukemia in August 2017, becoming the first drug specifically targeting cancer metabolism to be used for cancer treatment. He has worked in a variety of areas including biochemistry, immunology, and cancer genetics.
Early life
Born in southern China in 1946 to parents who were silk merchants, and raised in Hong Kong, parents encouraged him to become a doctor, his interests lay elsewhere—in math, biology, and chemistry. Mak and his family moved to the United States of America during the mid-1960s and with the choice of going to the University of California or Wisconsin, he was persuaded by his mother to attend Wisconsin to avoid the antiwar activities at California. His interest in life and chemistry led him to eventually studying biochemistry and biophysics at the University of Wisconsin.
University life
At the University of Wisconsin, Mak met virologist Roland Rueckert. Mak initially went to his lab t
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https://en.wikipedia.org/wiki/Cellular%20neural%20network
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In computer science and machine learning, cellular neural networks (CNN) or cellular nonlinear networks (CNN) are a parallel computing paradigm similar to neural networks, with the difference that communication is allowed between neighbouring units only. Typical applications include image processing, analyzing 3D surfaces, solving partial differential equations, reducing non-visual problems to geometric maps, modelling biological vision and other sensory-motor organs.
CNN is not to be confused with convolutional neural network (also colloquially called CNN).
CNN architecture
Due to their number and variety of architectures, it is difficult to give a precise definition for a CNN processor. From an architecture standpoint, CNN processors are a system of finite, fixed-number, fixed-location, fixed-topology, locally interconnected, multiple-input, single-output, nonlinear processing units. The nonlinear processing units are often referred to as neurons or cells. Mathematically, each cell can be modeled as a dissipative, nonlinear dynamical system where information is encoded via its initial state, inputs and variables used to define its behavior. Dynamics are usually continuous, as in the case of Continuous-Time CNN (CT-CNN) processors, but can be discrete, as in the case of Discrete-Time CNN (DT-CNN) processors.
Each cell has one output, by which it communicates its state with both other cells and external devices. Output is typically real-valued, but can be complex or even q
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https://en.wikipedia.org/wiki/Paul%20Zeitz
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Paul Zeitz (born July 5, 1958) is a Professor of Mathematics at the University of San Francisco. He is the author of The Art and Craft of Problem Solving, and a co-author of Statistical Explorations with Excel.
Biography
In 1974 Paul Zeitz won the USA Mathematical Olympiad (USAMO) and was a member of the first American team to participate in the International Mathematical Olympiad (IMO). The following year he graduated from Stuyvesant High School.
He earned a Westinghouse scholarship and graduated from Harvard University in 1981.
Since 1985, he has composed and edited problems for several national math contests, including the USAMO. He has helped train several American IMO teams, most notably the 1994 "Dream Team", the first team from any country to score a perfect 252 in the Olympiad. (The only other team to have ever done so was China's 2022 team.)
Zeitz founded the Bay Area Math Meet in 1994 and co-founded the Bay Area Mathematical Olympiad in 1999. In 1999 he wrote The Art and Craft of Problem Solving , a popular book on problem solving.
In 2003 Zeitz received from the Mathematical Association of America the Deborah and Franklin Haimo Awards for Distinguished College or University Teaching of Mathematics.
References
Stuyvesant High School alumni
1958 births
Living people
Harvard University alumni
University of San Francisco faculty
20th-century American mathematicians
21st-century American mathematicians
International Mathematical Olympiad participants
Mathematic
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https://en.wikipedia.org/wiki/Cleanroom%20suit
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A cleanroom suit, clean room suit, or bunny suit, is an overall garment worn in a cleanroom, an environment with a controlled level of contamination. One common type is an all-in-one coverall worn by semiconductor and nanotechnology line production workers, technicians, and process / equipment engineers. Similar garments are worn by people in similar roles creating sterile products for the medical device, biopharmaceutical and optical instrument industries.
The suit covers the wearer to prevent skin and hair being shed into a clean room environment. The suit may be in one piece or consist of several separate garments worn tightly together. The suit incorporates both boots and hood, designed to be breathable and lightweight while protecting the wearer. Polypropylene with a polyethylene coating, or Tyvek polyethylene are standard. The materials found in cleanroom suits can also be found on personal protective equipment.
More advanced designs with face covers were introduced in the 1990s (like the Intel fab worker-style suits seen on the Pentium product advertisements).
Suits are usually deposited in a storage bin after being contaminated for dry cleaning, autoclaving and/or repair.
The term "bunny suit" is also used for hazmat suits, worn by workers handling high-risk hazardous biological or chemical substances, as well as in the containment areas of nuclear power plants. These suits consist of the main garment, hood, thin cotton gloves, rubber gloves, plastic bags over
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https://en.wikipedia.org/wiki/Information%20gain%20%28decision%20tree%29
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In information theory and machine learning, information gain is a synonym for Kullback–Leibler divergence; the amount of information gained about a random variable or signal from observing another random variable. However, in the context of decision trees, the term is sometimes used synonymously with mutual information, which is the conditional expected value of the Kullback–Leibler divergence of the univariate probability distribution of one variable from the conditional distribution of this variable given the other one.
The information gain of a random variable X obtained from an observation of a random variable A taking value is defined the Kullback–Leibler divergence of the prior distribution for x from the posterior distribution for x given a.
The expected value of the information gain is the mutual information of X and A – i.e. the reduction in the entropy of X achieved by learning the state of the random variable A.
In machine learning, this concept can be used to define a preferred sequence of attributes to investigate to most rapidly narrow down the state of X. Such a sequence (which depends on the outcome of the investigation of previous attributes at each stage) is called a decision tree and applied in the area of machine learning known as decision tree learning. Usually an attribute with high mutual information should be preferred to other attributes.
General definition
In general terms, the expected information gain is the reduction in information entro
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https://en.wikipedia.org/wiki/Perkin%20Medal
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The Perkin Medal is an award given annually by the Society of Chemical Industry (American Section) to a scientist residing in America for an "innovation in applied chemistry resulting in outstanding commercial development." It is considered the highest honor given in the US chemical industry.
The Perkin Medal was first awarded in 1906 to commemorate the 50th anniversary of the discovery of mauveine, the world's first synthetic aniline dye, by Sir William Henry Perkin, an English chemist. The award was given to Sir William on the occasion of his visit to the United States in the year before he died. It was next given in 1908 and has been given every year since then.
Recipients
See also
List of chemistry awards
References
Awards established in 1906
Chemistry awards
1906 establishments in the United States
Materials science awards
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https://en.wikipedia.org/wiki/Pythagoras%20tree%20%28fractal%29
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The Pythagoras tree is a plane fractal constructed from squares. Invented by the Dutch mathematics teacher Albert E. Bosman in 1942, it is named after the ancient Greek mathematician Pythagoras because each triple of touching squares encloses a right triangle, in a configuration traditionally used to depict the Pythagorean theorem.
If the largest square has a size of L × L, the entire Pythagoras tree fits snugly inside a box of size 6L × 4L. The finer details of the tree resemble the Lévy C curve.
Construction
The construction of the Pythagoras tree begins with a square. Upon this square are constructed two squares, each scaled down by a linear factor of /2, such that the corners of the squares coincide pairwise. The same procedure is then applied recursively to the two smaller squares, ad infinitum. The illustration below shows the first few iterations in the construction process.
This is the simplest symmetric triangle. Alternatively, the sides of the triangle are recursively equal proportions, leading to the sides being proportional to the square root of the inverse golden ratio, and the areas of the squares being in golden ratio proportion.
Area
Iteration n in the construction adds 2n squares of area , for a total area of 1. Thus the area of the tree might seem to grow without bound in the limit as n → ∞. However, some of the squares overlap starting at the order 5 iteration, and the tree actually has a finite area because it fits inside a 6×4 box.
It can be shown eas
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https://en.wikipedia.org/wiki/AVM
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AVM may refer to:
Medicine and biology
Acute viral meningitis, inflammation of the protective membranes covering the brain and spinal cord, caused by a viral infection
Arteriovenous malformation, a congenital disorder of the veins and arteries that make up the vascular system
Cerebral arteriovenous malformation, an abnormal connection of the veins and arteries in the brain
Avian vacuolar myelinopathy, a fatal neurological disease
Other
ActionScript Virtual Machine, a component of Adobe Flash Player
Adaptive Vehicle Make, a United States military project to design and manufacture defense systems and vehicles
Adarsha Vidya Mandir, a school in Lalitpur, Nepal
Air Vice-Marshal, a rank in the United Kingdom and many Commonwealth air forces
Associação Visão de Macau or Vision Macau, a political party in Macao
Astronomy Visualization Metadata, a standard for tagging digital astronomical images with astronomical information
Attribute value matrix, a compact notation in linguistics for listing attribute-value pairs describing a lexical entity
Automated Valuation Model, a mathematical model for analysis of residential property
Automatic vehicle monitoring, one of the applications of vehicle tracking systems
AVM GmbH, a German manufacturer of broadband modems and consumer networking devices
AVM Productions, a film production house in Tamil Nadu, India
A. V. Meiyappan, Indian filmmaker, founder of AVM Productions
AVM Runestone, an archaeological forgery found in 2001 near Kensington, M
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https://en.wikipedia.org/wiki/Game%20physics
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Computer animation physics or game physics are laws of physics as they are defined within a simulation or video game, and the programming logic used to implement these laws. Game physics vary greatly in their degree of similarity to real-world physics. Sometimes, the physics of a game may be designed to mimic the physics of the real world as accurately as is feasible, in order to appear realistic to the player or observer. In other cases, games may intentionally deviate from actual physics for gameplay purposes. Common examples in platform games include the ability to start moving horizontally or change direction in mid-air and the double jump ability found in some games. Setting the values of physical parameters, such as the amount of gravity present, is also a part of defining the game physics of a particular game.
There are several elements that form components of simulation physics including the physics engine, program code that is used to simulate Newtonian physics within the environment, and collision detection, used to solve the problem of determining when any two or more physical objects in the environment cross each other's path.
Physics simulations
There are two central types of physics simulations: rigid body and soft-body simulators. In a rigid body simulation objects are grouped into categories based on how they should interact and are less performance intensive. Soft-body physics involves simulating individual sections of each object such that it behav
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https://en.wikipedia.org/wiki/Gravidity%20and%20parity
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In biology and medicine, gravidity and parity are the number of times a female has been pregnant (gravidity) and carried the pregnancies to a viable gestational age (parity). These two terms are usually coupled, sometimes with additional terms, to indicate more details of the female's obstetric history. When using these terms:
Gravida indicates the number of times a female is or has been pregnant, regardless of the pregnancy outcome. A current pregnancy, if any, is included in this count. A multiple pregnancy (e.g., twins, triplets, etc.) is counted as 1.
Parity, or "para", indicates the number of births (including live births and stillbirths) where pregnancies reached viable gestational age. A multiple pregnancy (e.g., twins, triplets, etc.) carried to viable gestational age is still counted as 1.
Abortus is the number of pregnancies that were lost prior to viable gestational age for any reason, including induced abortions or miscarriages but not stillbirths. The abortus term is sometimes dropped when no pregnancies have been lost.
Gravidity in biology
In biology, the term "gravid" ( "burdened, heavy") is used to describe the condition of an animal (most commonly fish or reptiles) when carrying eggs internally. For example, Astatotilapia burtoni females can transform between reproductive states, one of which is gravid, and the other non-gravid. In entomology it describes a mated female insect.
Gravidity in human medicine
In human medicine, "gravidity" refers to the num
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https://en.wikipedia.org/wiki/Subculture%20%28biology%29
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In biology, a subculture is either a new cell culture or a microbiological culture made by transferring some or all cells from a previous culture to fresh growth medium. This action is called subculturing or passaging the cells. Subculturing is used to prolong the lifespan and/or increase the number of cells or microorganisms in the culture.
Role
Cell lines and microorganisms cannot be held in culture indefinitely due to the gradual rise in metabolites which may be toxic, the depletion of nutrients present in the culture medium, and an increase in cell count or population size due to growth. Once nutrients are depleted and levels of toxic byproducts increase, microorganisms in culture will enter the stationary phase, where proliferation is greatly reduced or ceased (the cell density value plateaus). When microorganisms from this culture are transferred into fresh media, nutrients trigger the growth of the microorganisms which will go through lag phase, a period of slow growth and adaptation to the new environment, followed by log phase, a period where the cells grow exponentially.
Subculture is therefore used to produce a new culture with a lower density of cells than the originating culture, fresh nutrients and no toxic metabolites allowing continued growth of the cells without risk of cell death. Subculture is important for both proliferating (e.g. a microorganism like E. coli) and non-proliferating (e.g. terminally differentiated white blood cells) cells. Subculturing ca
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https://en.wikipedia.org/wiki/Room%20synchronization
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The room synchronization technique is a form of concurrency control in computer science.
The room synchronization problem involves supporting a set of m mutually exclusive "rooms" where any number of users can execute code simultaneously in a shared room (any one of them), but no two users can simultaneously execute code in separate rooms.
Room synchronization can be used to implement asynchronous parallel queues and stacks with constant time access (assuming a fetch-and-add operation).
References
G.E. Blelloch, P. Cheng, P.B. Gibbons, Room synchronizations, Annual ACM Symposium on Parallel Algorithms and Architectures 2001, 122–133
See also
Monitor (synchronization).
The Single Threaded Apartment Model in Microsoft's Component Object Model#Threading, as used by Visual Basic.
Concurrency control
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https://en.wikipedia.org/wiki/Graeme%20MacDonald
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Graeme Patrick David MacDonald (30 July 1930 – 30 September 1997), sometimes credited as Graeme McDonald or Graham McDonald, was a British television producer and executive.
Early life
MacDonald was educated at St Paul's School, London and Jesus College, Cambridge, where he initially studied geology and physics, but changed to an arts degree. While at Cambridge he was vice-president of the Footlights and president of the University Players, but left without a degree.
Career
MacDonald began his career in 1960 as a trainee director at Granada Television. In 1966 he joined the BBC, becoming a producer in the drama department, working particularly on anthology play series such as The Wednesday Play (for which he produced some of Dennis Potter's early work), Thirty-Minute Theatre, and Theatre 625. In the 1970s he became the producer of the single play strand Play for Today, the successor to The Wednesday Play, during which he worked on many acclaimed pieces, such as Jack Rosenthal's Bar Mitzvah Boy (1976).
By this time one of the senior producers working in the BBC's drama department, in 1977 he was promoted to become the Head of Serials. This department was merged with the Series department in 1979, and MacDonald became head of the new larger Series & Serials department which ensued. In 1981, he was promoted again to succeed Shaun Sutton as the overall Head of Drama at BBC Television.
MacDonald became the Controller of BBC2 in 1983, the first ever BBC channel controller to
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https://en.wikipedia.org/wiki/Concurrency%20semantics
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In computer science, concurrency semantics is a way to give meaning to concurrent systems in a mathematically rigorous way. Concurrency semantics is often based on mathematical theories of concurrency such as various process calculi, the actor model, or Petri nets.
A more detailed account of concurrency semantics is given here: Concurrency (computer science).
Semantics
Formal methods
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https://en.wikipedia.org/wiki/Spider%20diagram
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In mathematics, a unitary spider diagram adds existential points to an Euler or a Venn diagram. The points indicate the existence of an attribute described by the intersection of contours in the Euler diagram. These points may be joined forming a shape like a spider. Joined points represent an "or" condition, also known as a logical disjunction.
A spider diagram is a boolean expression involving unitary spider diagrams and the logical symbols . For example, it may consist of the conjunction of two spider diagrams, the disjunction of two spider diagrams, or the negation of a spider diagram.
Example
In the image shown, the following conjunctions are apparent from the Euler diagram.
In the universe of discourse defined by this Euler diagram, in addition to the conjunctions specified above, all possible sets from A through B and D through G are available separately. The set C is only available as a subset of B. Often, in complicated diagrams, singleton sets and/or conjunctions may be obscured by other set combinations.
The two spiders in the example correspond to the following logical expressions:
Red spider:
Blue spider:
References
Howse, J. and Stapleton, G. and Taylor, H. Spider Diagrams London Mathematical Society Journal of Computation and Mathematics, (2005) v. 8, pp. 145–194. Accessed on January 8, 2012 here
Stapleton, G. and Howse, J. and Taylor, J. and Thompson, S. What can spider diagrams say? Proc. Diagrams, (2004) v. 168, pp. 169–219. Accessed on J
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https://en.wikipedia.org/wiki/Graded%20poset
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In mathematics, in the branch of combinatorics, a graded poset is a partially-ordered set (poset) P equipped with a rank function ρ from P to the set N of all natural numbers. ρ must satisfy the following two properties:
The rank function is compatible with the ordering, meaning that for all x and y in the order, if x < y then ρ(x) < ρ(y), and
The rank is consistent with the covering relation of the ordering, meaning that for all x and y, if y covers x then ρ(y) = ρ(x) + 1.
The value of the rank function for an element of the poset is called its rank. Sometimes a graded poset is called a ranked poset but that phrase has other meanings; see Ranked poset. A rank or rank level of a graded poset is the subset of all the elements of the poset that have a given rank value.
Graded posets play an important role in combinatorics and can be visualized by means of a Hasse diagram.
Examples
Some examples of graded posets (with the rank function in parentheses) are:
the natural numbers N with their usual order (rank: the number itself), or some interval [0, N] of this poset,
Nn, with the product order (sum of the components), or a subposet of it that is a product of intervals,
the positive integers, ordered by divisibility (number of prime factors, counted with multiplicity), or a subposet of it formed by the divisors of a fixed N,
the Boolean lattice of finite subsets of a set (number of elements of the subset),
the lattice of partitions of a set into finitely many parts, o
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https://en.wikipedia.org/wiki/Table%20of%20Clebsch%E2%80%93Gordan%20coefficients
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This is a table of Clebsch–Gordan coefficients used for adding angular momentum values in quantum mechanics. The overall sign of the coefficients for each set of constant , , is arbitrary to some degree and has been fixed according to the Condon–Shortley and Wigner sign convention as discussed by Baird and Biedenharn. Tables with the same sign convention may be found in the Particle Data Group's Review of Particle Properties and in online tables.
Formulation
The Clebsch–Gordan coefficients are the solutions to
Explicitly:
The summation is extended over all integer for which the argument of every factorial is nonnegative.
For brevity, solutions with and are omitted. They may be calculated using the simple relations
and
Specific values
The Clebsch–Gordan coefficients for j values less than or equal to 5/2 are given below.
When , the Clebsch–Gordan coefficients are given by .
SU(N) Clebsch–Gordan coefficients
Algorithms to produce Clebsch–Gordan coefficients for higher values of and , or for the su(N) algebra instead of su(2), are known.
A web interface for tabulating SU(N) Clebsch–Gordan coefficients is readily available.
References
External links
Online, Java-based Clebsch–Gordan Coefficient Calculator by Paul Stevenson
Other formulae for Clebsch–Gordan coefficients.
Web interface for tabulating SU(N) Clebsch–Gordan coefficients
Representation theory of Lie groups
Clebsch–Gordan coefficients
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