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https://en.wikipedia.org/wiki/Balloonist%20theory
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Balloonist theory was a theory in early neuroscience that attempted to explain muscle movement by asserting that muscles contract by inflating with air or fluid. The Greek physician Galen believed that muscles contracted due to a fluid flowing into them, and for 1500 years afterward, it was believed that nerves were hollow and that they carried fluid. René Descartes, who was interested in hydraulics and used fluid pressure to explain various aspects of physiology such as the reflex arc, proposed that "animal spirits" flowed into muscle and were responsible for their contraction. In the model, which Descartes used to explain reflexes, the spirits would flow from the ventricles of the brain, through the nerves, and to the muscles to animate the latter.
In 1667, Thomas Willis proposed that muscles may expand by the reaction of animal spirits with vital spirits. He hypothesized that this reaction would produce air in a manner similar to the reaction that causes an explosion, causing muscles to swell and produce movement.
This theory has now been superseded by the mainstream scientific community due to the establishment of neuroscience, which is supported by empirical evidence.
Physiological refutations of the theory
In 1667, Jan Swammerdam, a Dutch anatomist famous for working with insects, struck the first important blow against the balloonist theory. Swammerdam, who was the first to experiment on nerve-muscle preparations, showed that muscles do not increase in size when
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https://en.wikipedia.org/wiki/Mineralization
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Mineralization may refer to:
Biomineralization (mineralization in biology), when an inorganic substance precipitates in an organic matrix
Mineralized tissues are tissues that have undergone mineralization, including bones, teeth, antlers, and marine shells
Bone remodeling, involving demineralization and remineralization in bones
Ossification (osteogenesis), mineralization of bone
Mineralization (geology), the hydrothermal deposition of economically important metals in the formation of ore bodies or lodes
Mineralization (soil science), the release of plant-available compounds such as ammonium during decomposition
See also
Demineralisation (disambiguation)
Remineralization (disambiguation)
Remineralisation of teeth (including de- and remineralization of teeth as an ongoing process)
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https://en.wikipedia.org/wiki/Annihilator%20method
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In mathematics, the annihilator method is a procedure used to find a particular solution to certain types of non-homogeneous ordinary differential equations (ODE's). It is similar to the method of undetermined coefficients, but instead of guessing the particular solution in the method of undetermined coefficients, the particular solution is determined systematically in this technique. The phrase undetermined coefficients can also be used to refer to the step in the annihilator method in which the coefficients are calculated.
The annihilator method is used as follows. Given the ODE , find another differential operator such that . This operator is called the annihilator, hence the name of the method. Applying to both sides of the ODE gives a homogeneous ODE for which we find a solution basis as before. Then the original inhomogeneous ODE is used to construct a system of equations restricting the coefficients of the linear combination to satisfy the ODE.
This method is not as general as variation of parameters in the sense that an annihilator does not always exist.
Annihilator table
Where is in the natural numbers, and are in the real numbers.
If consists of the sum of the expressions given in the table, the annihilator is the product of the corresponding annihilators.
Example
Given , .
The simplest annihilator of is . The zeros of are , so the solution basis of is
Setting we find
giving the system
which has solutions
,
giving the solution set
T
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https://en.wikipedia.org/wiki/Broken%20diagonal
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In recreational mathematics and the theory of magic squares, a broken diagonal is a set of n cells forming two parallel diagonal lines in the square. Alternatively, these two lines can be thought of as wrapping around the boundaries of the square to form a single sequence.
In pandiagonal magic squares
A magic square in which the broken diagonals have the same sum as the rows, columns, and diagonals is called a pandiagonal magic square.
Examples of broken diagonals from the number square in the image are as follows: 3,12,14,5; 10,1,7,16; 10,13,7,4; 15,8,2,9; 15,12,2,5; and 6,13,11,4.
The fact that this square is a pandiagonal magic square can be verified by checking that all of its broken diagonals add up to the same constant:
3+12+14+5 = 34
10+1+7+16 = 34
10+13+7+4 = 34
One way to visualize a broken diagonal is to imagine a "ghost image" of the panmagic square adjacent to the original:
111x121px
The set of numbers {3, 12, 14, 5} of a broken diagonal, wrapped around the original square, can be seen starting with the first square of the ghost image and moving down to the left.
In linear algebra
Broken diagonals are used in a formula to find the determinant of 3 by 3 matrices.
For a 3 × 3 matrix A, its determinant is
Here, and are (products of the elements of) the broken diagonals of the matrix.
Broken diagonals are used in the calculation of the determinants of all matrices of size 3 × 3 or larger. This can be shown by using the matrix's minors to calculate
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https://en.wikipedia.org/wiki/Lagrangian%20Grassmannian
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In mathematics, the Lagrangian Grassmannian is the smooth manifold of Lagrangian subspaces of a real symplectic vector space V. Its dimension is n(n + 1) (where the dimension of V is 2n). It may be identified with the homogeneous space
,
where is the unitary group and the orthogonal group. Following Vladimir Arnold it is denoted by Λ(n). The Lagrangian Grassmannian is a submanifold of the ordinary Grassmannian of V.
A complex Lagrangian Grassmannian is the complex homogeneous manifold of Lagrangian subspaces of a complex symplectic vector space V of dimension 2n. It may be identified with the homogeneous space of complex dimension n(n + 1)
,
where is the compact symplectic group.
As a homogeneous space
To see that the Lagrangian Grassmannian Λ(n) can be identified with , note that is a 2n-dimensional real vector space, with the imaginary part of its usual inner product making it into a symplectic vector space. The Lagrangian subspaces of are then the real subspaces of real dimension n on which the imaginary part of the inner product vanishes. An example is . The unitary group acts transitively on the set of these subspaces, and the stabilizer of is the orthogonal group . It follows from the theory of homogeneous spaces that Λ(n) is isomorphic to as a homogeneous space of .
Topology
The stable topology of the Lagrangian Grassmannian and complex Lagrangian Grassmannian is completely understood, as these spaces appear in the Bott periodicity theorem: , an
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https://en.wikipedia.org/wiki/Hydraulic%20cylinder
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A hydraulic cylinder (also called a linear hydraulic motor) is a mechanical actuator that is used to give a unidirectional force through a unidirectional stroke. It has many applications, notably in construction equipment (engineering vehicles), manufacturing machinery, elevators, and civil engineering.
A hydraulic cylinder is a hydraulic actuator that provides linear motion when hydraulic energy is converted into mechanical movement. It can be likened to a muscle in that, when the hydraulic system of a machine is activated, the cylinder is responsible for providing the motion.
Operation
Hydraulic cylinders get their power from pressurized hydraulic fluid, which is incompressible. Typically oil is used as hydraulic fluid. The hydraulic cylinder consists of a cylinder barrel, in which a piston connected to a piston rod moves back and forth. The barrel is closed on one end by the cylinder bottom (also called the cap) and the other end by the cylinder head (also called the gland) where the piston rod comes out of the cylinder. The piston has sliding rings and seals. The piston divides the inside of the cylinder into two chambers, the bottom chamber (cap end) and the piston rod side chamber (rod end/head-end).
Flanges, trunnions, clevises, and lugs are common cylinder mounting options. The piston rod also has mounting attachments to connect the cylinder to the object or machine component that it is pushing or pulling.
A hydraulic cylinder is the actuator or "motor" side of t
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https://en.wikipedia.org/wiki/List%20of%20exceptional%20set%20concepts
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This is a list of exceptional set concepts. In mathematics, and in particular in mathematical analysis, it is very useful to be able to characterise subsets of a given set X as 'small', in some definite sense, or 'large' if their complement in X is small. There are numerous concepts that have been introduced to study 'small' or 'exceptional' subsets. In the case of sets of natural numbers, it is possible to define more than one concept of 'density', for example. See also list of properties of sets of reals.
Almost all
Almost always
Almost everywhere
Almost never
Almost surely
Analytic capacity
Closed unbounded set
Cofinal (mathematics)
Cofinite
Dense set
IP set
2-large
Large set (Ramsey theory)
Meagre set
Measure zero
Natural density
Negligible set
Nowhere dense set
Null set, conull set
Partition regular
Piecewise syndetic set
Schnirelmann density
Small set (combinatorics)
Stationary set
Syndetic set
Thick set
Thin set (Serre)
Exceptional
Exceptional
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https://en.wikipedia.org/wiki/Cycloheptatriene
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Cycloheptatriene (CHT) is an organic compound with the formula C7H8. It is a closed ring of seven carbon atoms joined by three double bonds (as the name implies) and four single bonds. This colourless liquid has been of recurring theoretical interest in organic chemistry. It is a ligand in organometallic chemistry and a building block in organic synthesis. Cycloheptatriene is not aromatic, as reflected by the nonplanarity of the methylene bridge (-CH2-) with respect to the other atoms; however the related tropylium cation is.
Synthesis
Albert Ladenburg first generated cycloheptatriene in 1881 by the decomposition of tropine. The structure was finally proven by the synthesis of Richard Willstätter in 1901. This synthesis started from cycloheptanone and established the seven membered ring structure of the compound.
Cycloheptatriene can be obtained in the laboratory by photochemical reaction of benzene with diazomethane or the pyrolysis of the adduct of cyclohexene and dichlorocarbene. A related classic synthesis for cycloheptatriene derivatives, the Buchner ring enlargement, starts with the reaction of benzene with ethyl diazoacetate to give the corresponding norcaradiene ethyl ester, which then undergoes a thermally-allowed electrocyclic ring expansion to give 1,3,5-cycloheptatriene 7-carboxylic acid ethyl ester.
Reactions
Removal of a hydride ion from the methylene bridge gives the planar and aromatic cycloheptatriene cation, also called the tropylium ion. A practical r
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https://en.wikipedia.org/wiki/Heritability%20of%20autism
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The heritability of autism is the proportion of differences in expression of autism that can be explained by genetic variation; if the heritability of a condition is high, then the condition is considered to be primarily genetic. Autism has a strong genetic basis. Although the genetics of autism are complex, autism spectrum disorder (ASD) is explained more by multigene effects than by rare mutations with large effects.
Autism is known to have a strong genetic component, with studies consistently demonstrating a higher prevalence among siblings and in families with a history of autism. This led researchers to investigate the extent to which genetics contribute to the development of autism. Numerous studies, including twin studies and family studies, have estimated the heritability of autism to be around 80 to 90%, indicating that genetic factors play a substantial role in its etiology. Heritability estimates do not imply that autism is solely determined by genetics, as environmental factors also contribute to the development of the disorder.
Studies of twins from 1977 to 1995 estimated the heritability of autism to be more than 90%; in other words, that 90% of the differences between autistic and non-autistic individuals are due to genetic effects. When only one identical twin is autistic, the other often has learning or social disabilities. For adult siblings, the likelihood of having one or more features of the broad autism phenotype might be as high as 30%, much higher th
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https://en.wikipedia.org/wiki/Otto%20Laporte
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Otto Laporte (July 23, 1902 – March 28, 1971) was a German-born American physicist who made contributions to quantum mechanics, electromagnetic wave propagation theory, spectroscopy, and fluid dynamics. His name is lent to the Laporte rule in spectroscopy and to the Otto Laporte Award of the American Physical Society.
Education
Laporte’s ancestors came from French Huguenot families who fled to Switzerland in the 17th century. His father was an officer in the military. Before World War I, they were stationed in the fortified cities of Mainz (where Laporte was born), Cologne, and Metz, in which he received his early education. After the war started, they returned to Mainz.
In the spring of 1920, the family moved to Frankfurt, staying just one year, where Laporte attended the University of Frankfurt. There, he was influenced by the mathematicians Arthur Schoenflies, Ludwig Bieberbach, and Ernst Hellinger, and the physicists Max Born, and Alfred Landé. In the summer of 1921, the Laporte family moved to Munich, where Laporte became a student of Arnold Sommerfeld at the Ludwig Maximilian University of Munich (LMU). Max Born had sent an enthusiastic recommendation of Laporte to Sommerfeld. At that time, Wolfgang Pauli was an assistant to Sommerfeld and Sommerfeld’s students included Werner Heisenberg, Gregor Wentzel, Karl Herzfeld, and Paul Peter Ewald – all of whom would go on to become famous physicists in their own right. Laporte’s first independent research was on the diffrac
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https://en.wikipedia.org/wiki/Faculty%20of%20Informatics%20and%20Information%20Technologies
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The Faculty of Informatics and Information Technology () is one of the faculties of the Slovak University of Technology in Bratislava in Bratislava, the capital of Slovakia.
The Faculty was created in 2003 by separating from the Faculty of Electrical Engineering and Information Technology. It provides university education in computer science and computer engineering. After three years of study, the students can attain the Bachelor's degree and after two more years the Master of Science degree. The Faculty also offers three-year doctoral study.
All of the study programs have Slovak accreditation as well as the international accreditation from Engineering Council of United Kingdom.
In Shanghai ranking 2012 Slovak University of Technology has reached 100-150 position in informatics in the world, as the only University in Central Europe evaluated in the first 200.
Institutes
Institute of Applied Informatics
Institute of Informatics and Software Engineering
Institute of Computer Systems and Networks
Accredited study programs
Bachelor's degree study programmes
3 years full-time study
Informatics
Computer and Communication Systems and Networks
master's degree study programmes
2 years full-time study, 3 years full-time study (for students who graduated in a different field)
Computer and Communication Systems and Networks (as an orientation in Computer Engineering)
Software Engineering
Information Systems
Doctoral degree study programmes
3 years full-time study, 5 years part-
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https://en.wikipedia.org/wiki/Saxon%20math
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Saxon math, developed by John Saxon (1923–1996), is a teaching method for incremental learning of mathematics created in the 1980s. It involves teaching a new mathematical concept every day and constantly reviewing old concepts. Early editions were deprecated for providing very few opportunities to practice the new material before plunging into a review of all previous material. Newer editions typically split the day's work evenly between practicing the new material and reviewing old material. It uses a steady review of all previous material, with a focus on students who struggle with retaining the math they previously learned. However, it has sometimes been criticized for its heavy emphasis on rote rather than conceptual learning.
The Saxon Math 1 to Algebra 1/2 (the equivalent of a Pre-Algebra book) curriculum is designed so that students complete assorted mental math problems, learn a new mathematical concept, practice problems relating to that lesson, and solve a variety of problems. Daily practice problems include relevant questions from the current day's lesson as well as cumulative problems. This daily cycle is interrupted for tests and additional topics. From Algebra 1/2 on, the higher level books remove the mental math problems and incorporate testing more frequently.
Saxon Publishers has also published a phonics and spelling curriculum. This curriculum, authored by Lorna Simmons and first published in 2005, follows the same incremental principles as the Saxon Ma
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https://en.wikipedia.org/wiki/Leonard%20Lee
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Leonard G. Lee CM (July 17, 1938 – July 7, 2016) was a Canadian entrepreneur and founder of Lee Valley Tools and Canica Design. Lee was born in 1938 in Wadena, Sask., and grew up in a log cabin without electricity or running water.
He received a diploma in civil engineering from Royal Roads Military College and a Bachelor of Economics degree in 1963 from Queen's University. He worked for the federal government for sixteen years as a topographical surveyor, member of the Canadian Foreign Service and civil servant in the Department of Industry.
In 1978, he founded Lee Valley Tools, a Canadian woodworking and gardening tools mail-order business which has since grown into a multimillion-dollar enterprise. In 1985, he founded Veritas Tools. In 1991, he founded Algrove Publishing. In 1998, with his son Robin running Lee Valley Tools, Lee started a new business, Canica Design, a medical/surgical instrument company, headquartered in Almonte, Ontario.
In 2002, he was made a Member of the Order of Canada for "being a successful entrepreneur." In 2007, he was granted an honorary degree from the Royal Military College of Canada in Kingston, Ontario. In 2011, he was granted an honorary doctorate from the University of Ottawa. Lee died on July 7, 2016, from effects of vascular dementia.
Bibliography
The Complete Guide to Sharpening. Taunton Press, 1995. (hard cover) (soft cover).
References
Canadian businesspeople
Members of the Order of Canada
Queen's University at Kingston alumni
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https://en.wikipedia.org/wiki/Scannerless%20parsing
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In computer science, scannerless parsing (also called lexerless parsing) performs tokenization (breaking a stream of characters into words) and parsing (arranging the words into phrases) in a single step, rather than breaking it up into a pipeline of a lexer followed by a parser, executing concurrently. A language grammar is scannerless if it uses a single formalism to express both the lexical (word level) and phrase level structure of the language.
Dividing processing into a lexer followed by a parser is more modular; scannerless parsing is primarily used when a clear lexer–parser distinction is unneeded or unwanted. Examples of when this is appropriate include TeX, most wiki grammars, makefiles, simple application-specific scripting languages, and Raku.
Advantages
Only one metalanguage is needed
Non-regular lexical structure is handled easily
"Token classification" is unneeded which removes the need for design accommodations such as "the lexer hack" and language reserved words (such as "while" in C)
Grammars can be compositional (can be merged without human intervention)
Disadvantages
Since the lexical scanning and syntactic parsing are combined, the resulting parser tends to be more complicated and thus harder to understand and debug. The same will hold for the associated grammar, if a grammar is used to generate the parser.
The resulting parser tends to be significantly less efficient than a lexer-parser pipeline with regard to both time and memory.
Implementa
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https://en.wikipedia.org/wiki/Pseudoconvexity
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In mathematics, more precisely in the theory of functions of several complex variables, a pseudoconvex set is a special type of open set in the n-dimensional complex space Cn. Pseudoconvex sets are important, as they allow for classification of domains of holomorphy.
Let
be a domain, that is, an open connected subset. One says that is pseudoconvex (or Hartogs pseudoconvex) if there exists a continuous plurisubharmonic function on such that the set
is a relatively compact subset of for all real numbers In other words, a domain is pseudoconvex if has a continuous plurisubharmonic exhaustion function. Every (geometrically) convex set is pseudoconvex. However, there are pseudoconvex domains which are not geometrically convex.
When has a (twice continuously differentiable) boundary, this notion is the same as Levi pseudoconvexity, which is easier to work with. More specifically, with a boundary, it can be shown that has a defining function, i.e., that there exists which is so that , and . Now, is pseudoconvex iff for every and in the complex tangent space at p, that is,
, we have
The definition above is analogous to definitions of convexity in Real Analysis.
If does not have a boundary, the following approximation result can be useful.
Proposition 1 If is pseudoconvex, then there exist bounded, strongly Levi pseudoconvex domains with (smooth) boundary which are relatively compact in , such that
This is because once we have a as
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https://en.wikipedia.org/wiki/Domain%20of%20holomorphy
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In mathematics, in the theory of functions of several complex variables, a domain of holomorphy is a domain which is maximal in the sense that there exists a holomorphic function on this domain which cannot be extended to a bigger domain.
Formally, an open set in the n-dimensional complex space is called a domain of holomorphy if there do not exist non-empty open sets and where is connected, and such that for every holomorphic function on there exists a holomorphic function on with on
In the case, every open set is a domain of holomorphy: we can define a holomorphic function with zeros accumulating everywhere on the boundary of the domain, which must then be a natural boundary for a domain of definition of its reciprocal. For this is no longer true, as it follows from Hartogs' lemma.
Equivalent conditions
For a domain the following conditions are equivalent:
is a domain of holomorphy
is holomorphically convex
is pseudoconvex
is Levi convex - for every sequence of analytic compact surfaces such that for some set we have ( cannot be "touched from inside" by a sequence of analytic surfaces)
has local Levi property - for every point there exist a neighbourhood of and holomorphic on such that cannot be extended to any neighbourhood of
Implications are standard results (for , see Oka's lemma). The main difficulty lies in proving , i.e. constructing a global holomorphic function which admits no extension from non-extendable function
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https://en.wikipedia.org/wiki/Fj%C3%B6lnir%20%28programming%20language%29
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Fjölnir (also Fjolnir or Fjoelnir) is a programming language developed by professor Snorri Agnarsson of computer science at Háskóli Íslands (University of Iceland) that was mostly used in the 1980s. The source files usually have the extension fjo or sma.
Features
Fjölnir is based on the concept of representing programs as trees, and packages by substitutions on trees using algebraic operators. For example, in the Hello World example below, "GRUNNUR" is a package, the block of code between braces is a package, and * is an operator that substitutes names in one package with elements from another. In this case, skrifastreng (which writes a string to the standard output) is imported from "GRUNNUR".
Code examples
;; Hello world in Fjölnir
"hello" < main
{
main ->
stef(;)
stofn
skrifastreng(;"Hello, world!"),
stofnlok
}
*
"GRUNNUR"
;
External links
Fjölnir package (DOS, works in older versions of Windows)
PDF about Fjölnir (In Icelandic)
99 Bottles of Beer in Fjölnir
The original source for both Fjölnir 1 and Fjölnir 2; coded in Fjölnir itself.
References
Non-English-based programming languages
Icelandic language
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https://en.wikipedia.org/wiki/Pseudoconvex%20function
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In convex analysis and the calculus of variations, both branches of mathematics, a pseudoconvex function is a function that behaves like a convex function with respect to finding its local minima, but need not actually be convex. Informally, a differentiable function is pseudoconvex if it is increasing in any direction where it has a positive directional derivative. The property must hold in all of the function domain, and not only for nearby points.
Formal definition
Consider a differentiable function , defined on a (nonempty) convex open set of the finite-dimensional Euclidean space . This function is said to be pseudoconvex if the following property holds:
Equivalently:
Here is the gradient of , defined by:
Note that the definition may also be stated in terms of the directional derivative of , in the direction given by the vector . This is because, as is differentiable, this directional derivative is given by:
Properties
Relation to other types of "convexity"
Every convex function is pseudoconvex, but the converse is not true. For example, the function is pseudoconvex but not convex. Similarly, any pseudoconvex function is quasiconvex; but the converse is not true, since the function is quasiconvex but not pseudoconvex. This can be summarized schematically as:
To see that is not pseudoconvex, consider its derivative at : . Then, if was pseudoconvex, we should have:
In particular it should be true for . But it is not, as: .
Sufficient optimality conditi
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https://en.wikipedia.org/wiki/Energy%20systems%20language
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The energy systems language, also referred to as energese, or energy circuit language, or generic systems symbols, is a modelling language used for composing energy flow diagrams in the field of systems ecology. It was developed by Howard T. Odum and colleagues in the 1950s during studies of the tropical forests funded by the United States Atomic Energy Commission.
Design intent
The design intent of the energy systems language was to facilitate the generic depiction of energy flows through any scale system while encompassing the laws of physics, and in particular, the laws of thermodynamics (see energy transformation for an example).
In particular H.T. Odum aimed to produce a language which could facilitate the intellectual analysis, engineering synthesis and management of global systems such as the geobiosphere, and its many subsystems. Within this aim, H.T. Odum had a strong concern that many abstract mathematical models of such systems were not thermodynamically valid. Hence he used analog computers to make system models due to their intrinsic value; that is, the electronic circuits are of value for modelling natural systems which are assumed to obey the laws of energy flow, because, in themselves the circuits, like natural systems, also obey the known laws of energy flow, where the energy form is electrical. However Odum was interested not only in the electronic circuits themselves, but also in how they might be used as formal analogies for modeling other systems which
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https://en.wikipedia.org/wiki/Convex%20analysis
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Convex analysis is the branch of mathematics devoted to the study of properties of convex functions and convex sets, often with applications in convex minimization, a subdomain of optimization theory.
Convex sets
A subset of some vector space is if it satisfies any of the following equivalent conditions:
If is real and then
If is real and with then
Throughout, will be a map valued in the extended real numbers with a domain that is a convex subset of some vector space.
The map is a if
holds for any real and any with If this remains true of when the defining inequality () is replaced by the strict inequality
then is called .
Convex functions are related to convex sets. Specifically, the function is convex if and only if its
is a convex set. The epigraphs of extended real-valued functions play a role in convex analysis that is analogous to the role played by graphs of real-valued function in real analysis. Specifically, the epigraph of an extended real-valued function provides geometric intuition that can be used to help formula or prove conjectures.
The domain of a function is denoted by while its is the set
The function is called if and for Alternatively, this means that there exists some in the domain of at which and is also equal to In words, a function is if its domain is not empty, it never takes on the value and it also is not identically equal to If is a proper convex function then there exist some vector and
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https://en.wikipedia.org/wiki/Subharmonic%20function
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In mathematics, subharmonic and superharmonic functions are important classes of functions used extensively in partial differential equations, complex analysis and potential theory.
Intuitively, subharmonic functions are related to convex functions of one variable as follows. If the graph of a convex function and a line intersect at two points, then the graph of the convex function is below the line between those points. In the same way, if the values of a subharmonic function are no larger than the values of a harmonic function on the boundary of a ball, then the values of the subharmonic function are no larger than the values of the harmonic function also inside the ball.
Superharmonic functions can be defined by the same description, only replacing "no larger" with "no smaller". Alternatively, a superharmonic function is just the negative of a subharmonic function, and for this reason any property of subharmonic functions can be easily transferred to superharmonic functions.
Formal definition
Formally, the definition can be stated as follows. Let be a subset of the Euclidean space and let
be an upper semi-continuous function. Then, is called subharmonic if for any closed ball of center and radius contained in and every real-valued continuous function on that is harmonic in and satisfies for all on the boundary of , we have for all
Note that by the above, the function which is identically −∞ is subharmonic, but some authors exclude this function by defin
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https://en.wikipedia.org/wiki/Coherent%20backscattering
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In physics, coherent backscattering is observed when coherent radiation (such as a laser beam) propagates through a medium which has a large number of scattering centers (such as milk or a thick cloud) of size comparable to the wavelength of the radiation.
The waves are scattered many times while traveling through the medium. Even for incoherent radiation, the scattering typically reaches a local maximum in the direction of backscattering. For coherent radiation, however, the peak is two times higher.
Coherent backscattering is very difficult to detect and measure for two reasons. The first is fairly obvious, that it is difficult to measure the direct backscatter without blocking the beam, but there are methods for overcoming this problem. The second is that the peak is usually extremely sharp around the backward direction, so that a very high level of angular resolution is needed for the detector to see the peak without averaging its intensity out over the surrounding angles where the intensity can undergo large dips. At angles other than the backscatter direction, the light intensity is subject to numerous essentially random fluctuations called speckles.
This is one of the most robust interference phenomena that survives multiple scattering, and it is regarded as an aspect of a quantum mechanical phenomenon known as weak localization (Akkermans et al. 1986). In weak localization, interference of the direct and reverse paths leads to a net reduction of light transport in
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https://en.wikipedia.org/wiki/Diffie%E2%80%93Hellman%20problem
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The Diffie–Hellman problem (DHP) is a mathematical problem first proposed by Whitfield Diffie and Martin Hellman in the context of cryptography. The motivation for this problem is that many security systems use one-way functions: mathematical operations that are fast to compute, but hard to reverse. For example, they enable encrypting a message, but reversing the encryption is difficult. If solving the DHP were easy, these systems would be easily broken.
Problem description
The Diffie–Hellman problem is stated informally as follows:
Given an element g and the values of gx and gy, what is the value of gxy?
Formally, g is a generator of some group (typically the multiplicative group of a finite field or an elliptic curve group) and x and y are randomly chosen integers.
For example, in the Diffie–Hellman key exchange, an eavesdropper observes gx and gy exchanged as part of the protocol, and the two parties both compute the shared key gxy. A fast means of solving the DHP would allow an eavesdropper to violate the privacy of the Diffie–Hellman key exchange and many of its variants, including ElGamal encryption.
Computational complexity
In cryptography, for certain groups, it is assumed that the DHP is hard, and this is often called the Diffie–Hellman assumption. The problem has survived scrutiny for a few decades and no "easy" solution has yet been publicized.
As of 2006, the most efficient means known to solve the DHP is to solve the discrete logarithm problem (DLP), whic
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https://en.wikipedia.org/wiki/Indian%20National%20Mathematical%20Olympiad
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The Indian National Mathematical Olympiad (INMO) is a high school mathematics competition held annually in India since 1989. It is the third tier in the Indian team selection procedure for the International Mathematical Olympiad and is conducted by the Homi Bhabha Centre for Science Education (HBCSE) under the aegis of the National Board of Higher Mathematics (NBHM).
The Mathematical Olympiad Program is a five stage process conducted under the aegis of National Board for Higher Mathematics (NBHM). The first stage PRMO is conducted by the Mathematics Teachers’ Association (India). All the remaining stages are organized by Homi Bhabha Centre for Science Education (HBCSE).
Eligibility and participant selection process
The INMO is conducted by the MO Cell which is held on the third Sunday of January at 30 centers across the country. Prospective candidates first need to write the Pre-Regional Mathematical Olympiad (known as PRMO or Pre-RMO) then the Regional Mathematical Olympiad of their respective state or region. Around thirty students are selected from each region, to write the INMO. The best-performing students from the RMO (approximately 900) qualify for the second stage INMO.
Structure of the examination
The Indian National Mathematics Olympiad is the national level Olympiad which is conducted to select students for the International Mathematical Olympiad Training Camp, which is further conducted to select the Indian team for the International Mathematical Olympiad. It
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https://en.wikipedia.org/wiki/Bianchi%20group
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In mathematics, a Bianchi group is a group of the form
where d is a positive square-free integer. Here, PSL denotes the projective special linear group and is the ring of integers of the imaginary quadratic field .
The groups were first studied by as a natural class of discrete subgroups of , now termed Kleinian groups.
As a subgroup of , a Bianchi group acts as orientation-preserving isometries of 3-dimensional hyperbolic space . The quotient space is a non-compact, hyperbolic 3-fold with finite volume, which is also called Bianchi orbifold. An exact formula for the volume, in terms of the Dedekind zeta function of the base field , was computed by Humbert as follows. Let be the discriminant of , and , the discontinuous action on , then
The set of cusps of is in bijection with the class group of . It is well known that every non-cocompact arithmetic Kleinian group is weakly commensurable with a Bianchi group.
References
External links
Allen Hatcher, Bianchi Orbifolds
Group theory
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https://en.wikipedia.org/wiki/Weyl%20curvature%20hypothesis
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The Weyl curvature hypothesis, which arises in the application of Albert Einstein's general theory of relativity to physical cosmology, was introduced by the British mathematician and theoretical physicist Roger Penrose in an article in 1979 in an attempt to provide explanations for two of the most fundamental issues in physics. On the one hand, one would like to account for a universe which on its largest observational scales appears remarkably spatially homogeneous and isotropic in its physical properties (and so can be described by a simple Friedmann–Lemaître model); on the other hand, there is the deep question on the origin of the second law of thermodynamics.
Penrose suggests that the resolution of both of these problems is rooted in a concept of the entropy content of gravitational fields. Near the initial cosmological singularity (the Big Bang), he proposes, the entropy content of the cosmological gravitational field was extremely low (compared to what it theoretically could have been), and started rising monotonically thereafter. This process manifested itself e.g. in the formation of structure through the clumping of matter to form galaxies and clusters of galaxies. Penrose associates the initial low entropy content of the universe or the past hypothesis with the effective vanishing of the Weyl curvature tensor of the cosmological gravitational field near the Big Bang. From then on, he proposes, its dynamical influence gradually increased, thus being responsible fo
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https://en.wikipedia.org/wiki/BAE%20Systems%20Integrated%20System%20Technologies
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BAE Systems Integrated System Technologies (known informally as Insyte) was a division of BAE Systems plc. The division was a major supplier of defence electronics, integrated command and control systems, radars, simulators, meteorological systems, data links and C4ISR battle management systems
Insyte was formed on 3 May 2005, by bringing together BAE Systems' interests in C4ISR and the UK operations of AMS following the Eurosystems Transaction.
Its headquarters were in Frimley, Surrey, but the major activities of the division are carried out across 13 sites throughout England and Scotland.
In 2010 BAE Systems merged Integrated System Technologies into its air and naval businesses.
References
Aircraft component manufacturers of the United Kingdom
Avionics companies
Integrated System Technologies
Companies based in Surrey
Defunct technology companies of the United Kingdom
Science and technology in Surrey
Surrey Heath
Technology companies established in 2005
Technology companies disestablished in 2010
2005 establishments in England
2010 disestablishments in England
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https://en.wikipedia.org/wiki/Programming%20Computable%20Functions
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In computer science, Programming Computable Functions (PCF) is a typed functional language introduced by Gordon Plotkin in 1977, based on previous unpublished material by Dana Scott. It can be considered to be an extended version of the typed lambda calculus or a simplified version of modern typed functional languages such as ML or Haskell.
A fully abstract model for PCF was first given by Robin Milner. However, since Milner's model was essentially based on the syntax of PCF it was considered less than satisfactory. The first two fully abstract models not employing syntax were formulated during the 1990s. These models are based on game semantics and Kripke logical relations. For a time it was felt that neither of these models was completely satisfactory, since they were not effectively presentable. However, Ralph Loader demonstrated that no effectively presentable fully abstract model could exist, since the question of program equivalence in the finitary fragment of PCF is not decidable.
Syntax
The types of PCF are inductively defined as
nat is a type
For types σ and τ, there is a type σ → τ
A context is a list of pairs x : σ, where x is a variable name and σ is a type, such that no variable name is duplicated. One then defines typing judgments of terms-in-context in the usual way for the following syntactical constructs:
Variables (if x : σ is part of a context Γ, then Γ ⊢ x : σ)
Application (of a term of type σ → τ to a term of type σ)
λ-abstraction
The Y fixed po
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https://en.wikipedia.org/wiki/Fracture%20toughness
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In materials science, fracture toughness is the critical stress intensity factor of a sharp crack where propagation of the crack suddenly becomes rapid and unlimited. A component's thickness affects the constraint conditions at the tip of a crack with thin components having plane stress conditions and thick components having plane strain conditions. Plane strain conditions give the lowest fracture toughness value which is a material property. The critical value of stress intensity factor in mode I loading measured under plane strain conditions is known as the plane strain fracture toughness, denoted . When a test fails to meet the thickness and other test requirements that are in place to ensure plane strain conditions, the fracture toughness value produced is given the designation . Fracture toughness is a quantitative way of expressing a material's resistance to crack propagation and standard values for a given material are generally available.
Slow self-sustaining crack propagation known as stress corrosion cracking, can occur in a corrosive environment above the threshold and below . Small increments of crack extension can also occur during fatigue crack growth, which after repeated loading cycles, can gradually grow a crack until final failure occurs by exceeding the fracture toughness.
Material variation
Fracture toughness varies by approximately 4 orders of magnitude across materials. Metals hold the highest values of fracture toughness. Cracks cannot easily prop
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https://en.wikipedia.org/wiki/Ralph%20Steiner
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Ralph Steiner (February 8, 1899 – July 13, 1986) was an American photographer, pioneer documentarian and a key figure among avant-garde filmmakers in the 1930s.
Photographer
Born in Cleveland, Steiner studied chemistry at Dartmouth, but in 1921 entered the Clarence H. White School of Modern Photography. White helped Steiner in finding a job at the Manhattan Photogravure Company, and Steiner worked on making photogravure plates of scenes from Robert Flaherty's 1922 Nanook of the North.
Not long after, Steiner's work as a freelance photographer in New York began, working mostly in advertising and for publications like Ladies' Home Journal. With fellow graduate Anton Bruehl (1900–1982), in 1925, they opened a studio on 47th Street, producing a narrative series of amusing table-top shots of three cut‑out figures dressed in suits for The New Yorker magazine; advertisements for Weber and Heilbroner menswear in a running weekly series. Their client was wiped out in the Wall Street Crash.
Through the encouragement of fellow photographer Paul Strand, Steiner joined the left-of-center Film and Photo League around 1927. He was also to influence the photography of Walker Evans, giving him guidance, technical assistance, and one of his view cameras.
Filmmaker
In 1929, Steiner made his first film, H2O, a poetic evocation of water that captured the abstract patterns generated by waves. Although it was not the only film of its kind at the time – Joris Ivens made Regen (Rain) that same y
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https://en.wikipedia.org/wiki/John%20Robert%20Anderson%20%28psychologist%29
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John Robert Anderson (born August 27, 1947) is a Canadian-born American psychologist. He is currently professor of Psychology and Computer Science at Carnegie Mellon University.
Biography
Anderson obtained a B.A. from the University of British Columbia in 1968, and a Ph.D. in Psychology from Stanford in 1972. He became an assistant professor at Yale in 1972. He moved to the University of Michigan in 1973 as a Junior Fellow (and married Lynne Reder who was a graduate student there) and returned to Yale in 1976 with tenure. He was promoted to full professor at Yale in 1977 but moved to Carnegie Mellon University in 1978. From 1988 to 1989, he served as president of the Cognitive Science Society. He was elected to the American Academy of Arts and Sciences and the National Academy of Sciences and has received a series of awards:
1968: Governor General's Gold Medal: Graduated as top student in Arts and Sciences at University of British Columbia
1978: Early Career Award of the American Psychological Association
1989–1994: Research Scientist Award, NIMH
1994: American Psychological Association's Distinguished Scientific Career Award
1999: Elected to the National Academy of Sciences
1999: Fellow of American Academy of Arts and Sciences
2004: The David E. Rumelhart Prize, for Contributions to the Formal Analysis of Human Cognition
2005: Howard Crosby Warren Medal for outstanding achievement in Experimental Psychology in the United States and Canada, Society of Experiment
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https://en.wikipedia.org/wiki/Toda%20lattice
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The Toda lattice, introduced by , is a simple model for a one-dimensional crystal in solid state physics. It is famous because it is one of the earliest examples of a non-linear completely integrable system.
It is given by a chain of particles with nearest neighbor interaction, described by the Hamiltonian
and the equations of motion
where is the displacement of the -th particle from its equilibrium position,
and is its momentum (mass ),
and the Toda potential .
Soliton solutions
Soliton solutions are solitary waves spreading in time with no change to their shape and size and interacting with each other in a particle-like way. The general N-soliton solution of the equation is
where
with
where
and
.
Integrability
The Toda lattice is a prototypical example of a completely integrable system. To see this one uses Flaschka's variables
such that the Toda lattice reads
To show that the system is completely integrable, it suffices to find a Lax pair, that is, two operators L(t) and P(t) in the Hilbert space of square summable sequences such that the Lax equation
(where [L, P] = LP - PL is the Lie commutator of the two operators) is equivalent to the time derivative of Flaschka's variables. The choice
where f(n+1) and f(n-1) are the shift operators, implies that the operators L(t) for different t are unitarily equivalent.
The matrix has the property that its eigenvalues are invariant in time. These eigenvalues constitute independent integrals of motion, therefo
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https://en.wikipedia.org/wiki/Offset%20%28computer%20science%29
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In computer science, an offset within an array or other data structure object is an integer indicating the distance (displacement) between the beginning of the object and a given element or point, presumably within the same object. The concept of a distance is valid only if all elements of the object are of the same size (typically given in bytes or words).
For example, if A is an array of characters containing "abcdef", the fourth element containing the character 'd' has an offset of three from the start of A.
In assembly language
In computer engineering and low-level programming (such as assembly language), an offset usually denotes the number of address locations added to a base address in order to get to a specific absolute address. In this (original) meaning of offset, only the basic address unit, usually the 8-bit byte, is used to specify the offset's size. In this context an offset is sometimes called a relative address.
In IBM System/360 instructions, a 12-bit offset embedded within certain instructions provided a range of between 0 and 4096 bytes. For example, within an unconditional branch instruction (X'47F0Fxxx'), the xxx 12bit hexadecimal offset provided the byte offset from the base register (15) to branch to. An odd offset would cause a program check (unless the base register itself also contained an odd address)—since instructions had to be aligned on half-word boundaries to execute without a program or hardware interrupt.
The previous example describes a
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https://en.wikipedia.org/wiki/Trevor%20Truran
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Trevor Truran (born 1942) is a United Kingdom former mathematics teacher, best known as the creator of many games and puzzles. Truran began making up games as mathematical teaching aids. At one time his entire mathematics course for 9-13 year olds was based on games, puzzles and story situations.
Early games were published in Games & Puzzles Magazine and he became Puzzles Editor of that magazine and later of Top Puzzles. For over 13 years he wrote for Computer Talk magazine and included many new games and puzzles as well as early articles on the Rubik's Cube.
A nine-part puzzle Treasure Trail appeared in the Sunday Telegraph and he freelanced for many magazines and newspapers before taking up puzzling full-time in 1985 with the publishers now called Puzzler Media Ltd. In that time he has created and edited a wide variety of magazines from Wordsearch to mathematical but has largely concentrated on logical puzzling, providing much of the content to magazines such as Logical Puzzles.
He is the inventor of the logical puzzle now known as Mosaic (1980s) which was developed by Conceptis Ltd. and which had its first success on Japanese telephones.
He is credited by some as a possible founder or early creator of what might be called cross-referencing or row-and-column puzzles, where numbers outside a grid give information as to what to put inside the grid. An early example is Whittleword (1979) which was followed by Domino Deal, Ace in Place and others.
He is currently a Managin
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https://en.wikipedia.org/wiki/XDH
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XDH may refer to:
the XDH Assumption, or, the External Diffie-Hellman assumption, a mathematic assumption used in elliptic curve cryptography
xanthine dehydrogenase, an enzyme
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https://en.wikipedia.org/wiki/Anthony%20Zee
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Anthony Zee (, b. 1945) (Zee comes from /ʑi23/, the Shanghainese pronunciation of 徐) is a Chinese-American physicist, writer, and a professor at the Kavli Institute for Theoretical Physics and the physics department of the University of California, Santa Barbara.
After graduating from Princeton University, Zee obtained his PhD from Harvard University in 1970, supervised by Sidney Coleman. During 1970–72 and 1977–78, he was at the Institute for Advanced Study. From 1973 to 1978, he was an Alfred P. Sloan Fellow. In his first year as assistant professor at Princeton, Zee had Ed Witten as his teaching assistant and grader.
Zee has authored or co-authored more than 200 scientific publications and several books. He has written on particle physics, condensed matter physics, anomalies in physics, random matrix theory, superconductivity, the quantum Hall effect, and other topics in theoretical physics and evolutionary biology, as well as their various interrelations.
Zee is an accomplished teacher, covering both general relativity and quantum field theory. The culmination of his teaching is his highly regarded and widely praised "trilogy" of graduate level textbooks: Quantum Field Theory in a Nutshell, Einstein Gravity in a Nutshell, and Group Theory in a Nutshell for Physicists. He is also the author of several books for general readers about physics and Chinese culture.
Books
Technical:
1982. Unity of Forces in the Universe. Singapore: World Scientific.
2010. Quantum Field Theo
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https://en.wikipedia.org/wiki/Erick%20Weinberg
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Erick J. Weinberg (born August 29, 1947) is a theoretical physicist and professor of physics at Columbia University.
Weinberg received his undergraduate degree from Manhattan College in 1968. He obtained his Ph.D. from Harvard University in 1973 under the supervision of Sidney Coleman, with whom he discovered the Coleman–Weinberg mechanism for spontaneous symmetry breaking in quantum field theory. Weinberg works on various branches in high-energy theory, including black holes, vortices, Chern–Simons theory, magnetic monopoles in gauge theories and cosmic inflation. He also serves as the Editor of Physical Review D, as well as a visiting scholar of the Korea Institute for Advanced Study (KIAS).
Academic career
After receiving his doctorate, Weinberg went to the Institute for Advanced Study in Princeton, New Jersey as a postdoctoral researcher. In 1975, he became an assistant professor of physics at Columbia University. He was promoted to full professor in 1987. From 2002 to 2006, Weinberg served as the chair of Columbia University's physics department. Weinberg is still actively researching BPS monopoles and vacuum decay.
Notable works
Weinberg has worked on various branches in theoretical high energy physics, including the theory of spontaneous symmetry breaking, inflation, the theory of supersymmetric solitons, and the theory of vacuum decay via the nucleation of quantum/thermal bubbles.
Coleman–Weinberg potential
Spontaneous symmetry breaking occurs in a theory when th
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https://en.wikipedia.org/wiki/Chan%E2%80%93Paton%20factor
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In theoretical physics, the Chan–Paton factor (named after Jack E. Paton and Hong-Mo Chan) is a multivalued index associated with the endpoints of an open string. An open string can be interpreted as a flux tube connecting a quark and its antiparticle. The two Chan–Paton factors make the string transform as a tensor under a gauge group whose charges are carried by the endpoints of the strings.
The procedure of enabling isospin factors to be added to the Veneziano model is known as Chan–Paton rules or Chan–Paton method.
After the second superstring revolution in 1995, Chan–Paton factors are interpreted as labels that identify which (spacetime-filling) D-branes the stringy endpoints are attached to. The Chan–Paton factors have become a special case of a more general concept.
References
String theory
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https://en.wikipedia.org/wiki/String%20background
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In theoretical physics, a string background refers to the set of classical values of quantum fields in spacetime that correspond to classical solutions of string theory. Such a background is associated with geometry that solves Einstein's field equations (with higher order corrections) or their generalizations and with the values of other fields. These fields may encode the information about the shape of the hidden dimensions; the size of various electromagnetic fields and their generalizations; the values of fluxes; and the presence of additional objects such as D-branes and orientifold planes. The full physics of string theory can always be thought of as a system of infinitely many quantum fields expanded around a given string background.
See also
Background independence
String theory
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https://en.wikipedia.org/wiki/Mikheyev%E2%80%93Smirnov%E2%80%93Wolfenstein%20effect
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The Mikheyev–Smirnov–Wolfenstein effect (often referred to as the matter effect) is a particle physics process which modifies neutrino oscillations in matter of varying density. The MSW effect is broadly analogous to the differential retardation of sound waves in density-variable media, however it also involves the propagation dynamics of three separate quantum fields which experience distortion.
In free space, the separate rates of neutrino eigenstates lead to standard neutrino flavor oscillation. Within matter – such as within the Sun – the analysis is more complicated, as shown by Mikheyev, Smirnov and Wolfenstein. It leads to a wide admixture of emanating neutrino flavors, which provides a compelling solution to the solar neutrino problem.
Works in 1978 and 1979 by American physicist Lincoln Wolfenstein led to understanding that the oscillation parameters of neutrinos are changed in matter. In 1985, the Soviet physicists Stanislav Mikheyev and Alexei Smirnov predicted that a slow decrease of the density of matter can resonantly enhance the neutrino mixing. Later in 1986, Stephen Parke of Fermilab, Hans Bethe of Cornell University, and S. Peter Rosen and James Gelb of Los Alamos National Laboratory provided analytic treatments of this effect.
Summary
The presence of electrons in matter changes the instantaneous Hamiltonian eigenstates (mass eigenstates) of neutrinos due to the charged current's elastic forward scattering of the electron neutrinos (i.e., weak interacti
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https://en.wikipedia.org/wiki/Tetrahedron%20Letters
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Tetrahedron Letters is a weekly international journal for rapid publication of full original research papers in the field of organic chemistry. According to the Journal Citation Reports, the journal has a 2020 impact factor of 2.415.
Indexing
Tetrahedron Letters is indexed in:
References
See also
Tetrahedron
Tetrahedron: Asymmetry
Chemistry journals
Weekly journals
Academic journals established in 1959
Elsevier academic journals
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https://en.wikipedia.org/wiki/Accounts%20of%20Chemical%20Research
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Accounts of Chemical Research is a semi-monthly peer-reviewed scientific journal published by the American Chemical Society containing overviews of basic research and applications in chemistry and biochemistry. It was established in 1968 and the editor-in-chief is Cynthia J. Burrows (University of Utah).
Abstracting and indexing
The journal is abstracted and indexed in:
According to the Journal Citation Reports, the journal has a 2021 impact factor of 24.466.
References
External links
Chemical Research
Academic journals established in 1968
Monthly journals
English-language journals
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https://en.wikipedia.org/wiki/Sumaya%20Farhat%20Naser
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Sumaya Farhat Naser (, born 11 June 1948 in Bir Zeit) is a Palestinian Christian peace activist in the West Bank.
She attended Talitha Kumi, a boarding school in Beit Jala which was founded by Lutheran deaconesses in the 19th century. After gaining her university entrance qualification, she studied biology, geography and education at the University of Hamburg, Germany and received a doctor's degree in applied botany.
Between 1982 and 1997 she was a university lecturer in botany and ecology at the Palestinian Birzeit University north of Ramallah. Between 1997 and 2001 she was the manager of the Palestinian Jerusalem Center for Women, working for peace together with the Israeli group Bat Shalom.
Sumaya Farhat-Naser is known for her clear expressions of opinion in the media, and particularly for her various projects, in which she motivates Palestinian women to work on a peaceful resolution to the Israeli–Palestinian conflict.
Publications
Thymian und Steine (autobiography), Lenos Verlag, Basel 1995,
Daughter of the Olive Trees, Lenos Verlag, Basel 2003,
Disteln im Weinberg. Tagebuch aus Palästina, Lenos, Basel 2007,
Im Schatten des Feigenbaums, Lenos, Basel 2013,
Ein Leben für den Frieden, Lesebuch aus Palästina. Lenos, Basel 2017,
Awards
1989 Honorary Doctorate from the Theological Faculty of the University of Münster, Germany
1995 Bruno-Kreisky-Award for merits on Human Rights
1997 Mount Zion Award for Reconciliation
1997 Evangelical Book Award
2000 Peace Aw
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https://en.wikipedia.org/wiki/John%20Kelsey%20%28cryptanalyst%29
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John Kelsey is a cryptographer who works at NIST. His research interests include cryptanalysis and design of symmetric cryptography primitives (block ciphers, stream ciphers, cryptographic hash functions, MACs), analysis and design of cryptographic protocols, cryptographic random number generation, electronic voting, side-channel attacks on cryptography implementations, and anonymizing communications systems. He previously worked at Certicom and Counterpane Internet Security.
See also
Yarrow algorithm, a family of cryptographic pseudorandom number generators
Twofish, a symmetric key block cipher
External links
John Kelsey at DBLP
John Kelsey at NIST
Modern cryptographers
Living people
Year of birth missing (living people)
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https://en.wikipedia.org/wiki/Stieltjes%20moment%20problem
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In mathematics, the Stieltjes moment problem, named after Thomas Joannes Stieltjes, seeks necessary and sufficient conditions for a sequence (m0, m1, m2, ...) to be of the form
for some measure μ. If such a function μ exists, one asks whether it is unique.
The essential difference between this and other well-known moment problems is that this is on a half-line [0, ∞), whereas in the Hausdorff moment problem one considers a bounded interval [0, 1], and in the Hamburger moment problem one considers the whole line (−∞, ∞).
Existence
Let
and
Then { mn : n = 1, 2, 3, ... } is a moment sequence of some measure on with infinite support if and only if for all n, both
{ mn : n = 1, 2, 3, ... } is a moment sequence of some measure on with finite support of size m if and only if for all , both
and for all larger
Uniqueness
There are several sufficient conditions for uniqueness, for example, Carleman's condition, which states that the solution is unique if
References
Probability problems
Mathematical analysis
Moment (mathematics)
Mathematical problems
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https://en.wikipedia.org/wiki/Dmitri%20Ivanenko
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Dmitri Dmitrievich Ivanenko (, ; July 29, 1904 – December 30, 1994) was a Soviet theoretical physicist of Ukrainian origin who made great contributions to the physical science of the twentieth century, especially to nuclear physics, field theory, and gravitation theory. He worked in the Poltava Gravimetric Observatory of the Institute of Geophysics of NAS of Ukraine, was the head of the Theoretical Department Ukrainian Physico-Technical Institute in Kharkiv, Head of the Department of Theoretical Physics of the Kharkiv Institute of Mechanical Engineering. Professor of University of Kharkiv, Professor of Moscow State University (since 1943).
Biography
Dmitri Ivanenko was born on July 29, 1904, in Poltava (present-day Ukraine), where he finished school, in 1920–1923 he studied at the Poltava Pedagogical Institute and began his creative path as a teacher of physics in middle school. Then D. D. Ivanenko studied at Kharkiv University, from which in 1923 he was transferred to Petrograd University. In 1926, while still a student, he wrote his first scientific works: with George Gamow on the Kaluza–Klein five-dimensional theory and with Lev Landau on the problems of relativistic quantum mechanics.
After graduating from the university, from 1927 to 1930 D. Ivanenko was a scholarship student and then a research scientist at the Physical Mathematical Institute of Academy of Sciences of the USSR. During these years he collaborated with Lev Landau, Vladimir Fock and Viktor Ambartsumian,
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https://en.wikipedia.org/wiki/Knut%20J%C3%B8rgen%20R%C3%B8ed%20%C3%98degaard
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Knut Jørgen Røed Ødegaard (born 6 May 1966) is a Norwegian astronomer formerly employed as a media contact at the University of Oslo's Institute of Theoretical Astrophysics. He was the leader of the Norwegian Astronomical Society (2005–2008), and is also manager of the Harestua Solar Observatory.
His enthusiasm for astronomy has made him a popular interview object in Norwegian media for events such as the 2004 Transit of Venus and the 2005 landing of the Huygens probe on Titan, and for astronomy in general towards the general population.
References
1966 births
Living people
20th-century astronomers
21st-century astronomers
Norwegian astrophysicists
Norwegian science writers
Academic staff of the University of Oslo
People from Oppland
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https://en.wikipedia.org/wiki/%C3%89tienne%20Wenger
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Étienne Charles Wenger (born 1952) is an educational theorist and practitioner, best known for his formulation (with Jean Lave) of the theory of situated cognition and his more recent work in the field of communities of practice.
Life
Having grown up in the French-speaking parts of Switzerland, Wenger achieved a B.S. in Computer Science from the University of Geneva, Switzerland, in 1982. He then studied at the University of California, Irvine, in the United States, gaining an M.S. in Information and Computer Science in 1984 and a Ph.D. in the same subject area in 1990. He currently lives in California, United States.
Work
Wenger initially came upon the concept of communities of practice when he was approached by John Seely Brown, to join the Institute for Research of Learning. There Wenger worked with anthropologist Jean Lave, observing apprenticeships among traditional tailors in Africa. Through the study of these cases Lave and Wenger concluded that most learning does not take place with the master, it takes place among the apprentices.
Wenger holds that learning is an inherently social process and that it cannot be separated from the social context in which it happens. Among his current engagements are Communities of Practice for Accounting and Auditing Education as well as Audit and Oversight for the World Bank Centre for Financial Reporting Reform.
One of the first people to observe and study communities of practice, Etienne Wenger's work is applied in various
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https://en.wikipedia.org/wiki/Royo
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Royo is a surname of Spanish origin. Notable people with the surname include:
Andre Royo (born 1968), American actor, producer, and writer
Adela Ruiz de Royo (1943–2019), Spanish-born Panamanian mathematics academic and educator
Ángel Royo (born 1966), Spanish football manager
Antonio Royo Marín (1913–2005), Spanish Dominican priest and theologian
Aristides Royo ((born 1940), Panamanian politicians
Fernando Pérez Royo (born 1943), Spanish academic and politician
Josep Royo (born 1945), Catalan contemporary artist
Laura Royo (born 1999), Spanish football player
Luis Royo (born 1954), Spanish artist
Manel Royo (born 1994), Spanish football player
Manuela Royo Letelier (born 1982), Chilean historian and lawyer
Maria Alejandra Royo (born 2001), Panamanian beauty pageant titleholder
Reyna Royo (born 1971), Panamanian model and beauty pageant contestant
Romulo Royo (born 1976), Spanish contemporary artist
Rubén Royo (born 1987), Spanish football player
Spanish-language surnames
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https://en.wikipedia.org/wiki/Conjugate-permutable%20subgroup
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In mathematics, in the field of group theory, a conjugate-permutable subgroup is a subgroup that commutes with all its conjugate subgroups. The term was introduced by Tuval Foguel in 1997 and arose in the context of the proof that for finite groups, every quasinormal subgroup is a subnormal subgroup.
Clearly, every quasinormal subgroup is conjugate-permutable.
In fact, it is true that for a finite group:
Every maximal conjugate-permutable subgroup is normal.
Every conjugate-permutable subgroup is a conjugate-permutable subgroup of every intermediate subgroup containing it.
Combining the above two facts, every conjugate-permutable subgroup is subnormal.
Conversely, every 2-subnormal subgroup (that is, a subgroup that is a normal subgroup of a normal subgroup) is conjugate-permutable.
References
Subgroup properties
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https://en.wikipedia.org/wiki/American%20Institute%20of%20Mathematics
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The American Institute of Mathematics (AIM) is one of eight mathematical institutes in the United States, funded by the National Science Foundation (NSF). It was founded in 1994 by John Fry, co-founder of Fry's Electronics, and originally located in the Fry's Electronics store in San Jose, California. It was privately funded by Fry at inception, and has obtained NSF funding since 2002. From 2023 onwards, the institute will be located on the campus of the California Institute of Technology in Pasadena, California.
History
The institute was founded with the primary goal of identifying and solving important mathematical problems. Originally very small groups of top mathematicians would be assembled to solve a major problem, such as the Birch and Swinnerton-Dyer conjecture. Later, the institute began running a program of week-long workshops on current topics in mathematical research. These workshops rely strongly on interactive problem sessions.
Brian Conrey became the institute's director in 1997.
From 1998 to 2009 (with the exception of 1999), AIM annually awarded a five-year fellowship to an "outstanding new PhD pursuing research in an area of pure mathematics", but currently is not offering the fellowship. AIM also sponsors local mathematics competitions and a yearly meeting for women mathematicians.
The institute planned to move to Morgan Hill, California, about 39 miles (63 km) to the southeast of San Jose, when its new facility is completed. Plans for the new facilit
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https://en.wikipedia.org/wiki/Jay%20Pasachoff
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Jay Myron Pasachoff (July 1, 1943 – November 20, 2022) was an American astronomer. Pasachoff was Field Memorial Professor of Astronomy at Williams College and the author of textbooks and tradebooks in astronomy, physics, mathematics, and other sciences.
Biography
After the Bronx High School of Science, Pasachoff studied at Harvard, receiving his bachelor's degree in 1963, his master's degree in 1965, and his doctorate in 1969. His doctoral thesis was titled Fine Structure in the Solar Chromosphere. He worked at the Harvard College Observatory and Caltech before going to Williams College in 1972. His sabbaticals and other leaves have been at the University of Hawaii’s Institute for Astronomy, the Institut d'Astrophysique de Paris, the Institute for Advanced Study in Princeton, New Jersey, the Center for Astrophysics Harvard & Smithsonian in Cambridge, Massachusetts, Caltech in Pasadena, California, and most recently at the Carnegie Observatories, also in Pasadena. He has taken a leading role in the science and history of transits of Mercury and Venus, as an analogue to exoplanet studies, leading up to the transit of Venus, and the 2016 and 2019 transits of Mercury. Jay Pasachoff on solar eclipses: "Each time is like going to the seventh game of the World Series with the score tied in the ninth inning."
Pasachoff died on November 20, 2022, at the age of 79.
Work
Pasachoff observed with a wide variety of ground-based telescopes and spacecraft, and reported on those activitie
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https://en.wikipedia.org/wiki/Neal%20Francis%20Lane
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Cornelius Francis "Neal" Lane (born August 22, 1938), is an American physicist and senior fellow in science and technology policy at Rice University's Baker Institute for Public Policy and Malcolm Gillis University Professor Emeritus of Physics and Astronomy Emeritus at Rice University in Houston, Texas.
He has served as chancellor of the University of Colorado at Colorado Springs, provost of Rice University, and Science Advisor to the President (Assistant to the President for Science and Technology and director of the Office of Science and Technology Policy (OSTP) during the Bill Clinton Administration). Lane lectures and writes on matters of science and technology policy.
Biography
Early life
Lane was born in Oklahoma City in 1938, graduated from Southeast High School, and earned his B.S., M.S., and Ph.D. in physics from the University of Oklahoma. His thesis advisor was Chun Chia Lin.
Research, teaching and administration
Initially pursuing a career in teaching and research, Lane carried out post-doctoral studies in the Department of Applied Mathematics at Queen's University Belfast in Belfast, Northern Ireland, studying with Professor Alexander Dalgarno, and as a visiting fellow at the Joint Institute for Laboratory Astrophysics (currently JILA), working with Dr. Sydney Geltman. He joined Rice University as an assistant professor in 1966 and was promoted to full professor of physics, space physics, and astronomy in 1972. His research contributions were all in the
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https://en.wikipedia.org/wiki/%E2%89%A1
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The symbol ≡ (triple bar) is used in science and mathematics with several different meanings. It may refer to the following:
Mathematics
Identity (mathematics), identity of two mathematical expressions
Logical biconditional, in logic (if and only if)
Modular arithmetic, a ≡ b (mod m)
Equivalence relation, often denoted using a triple bar
Chemistry
Triple bond, a type of covalent bond between two atoms
Computing
Hamburger button, often used for drop-down menus
Symbol for the line feed character in ISO 2047
See also
≅, a symbol used in approximation
The eight trigrams of the Bagua: ☰, ☱, ☲, ☳, ☴, ☵, ☶, ☷
Ξ, capital letter Xi of the Greek alphabet
三, Chinese numeral for the number 3
Glossary of mathematical symbols
Tesla Model 3, whose logo originally stylized the digit 3 as three horizontal bars
III (disambiguation), three letter Is in a row
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https://en.wikipedia.org/wiki/Johnson%E2%80%93Corey%E2%80%93Chaykovsky%20reaction
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The Johnson–Corey–Chaykovsky reaction (sometimes referred to as the Corey–Chaykovsky reaction or CCR) is a chemical reaction used in organic chemistry for the synthesis of epoxides, aziridines, and cyclopropanes. It was discovered in 1961 by A. William Johnson and developed significantly by E. J. Corey and Michael Chaykovsky. The reaction involves addition of a sulfur ylide to a ketone, aldehyde, imine, or enone to produce the corresponding 3-membered ring. The reaction is diastereoselective favoring trans substitution in the product regardless of the initial stereochemistry. The synthesis of epoxides via this method serves as an important retrosynthetic alternative to the traditional epoxidation reactions of olefins.
The reaction is most often employed for epoxidation via methylene transfer, and to this end has been used in several notable total syntheses (See Synthesis of epoxides below). Additionally detailed below are the history, mechanism, scope, and enantioselective variants of the reaction. Several reviews have been published.
History
The original publication by Johnson concerned the reaction of 9-dimethylsulfonium fluorenylide with substituted benzaldehyde derivatives. The attempted Wittig-like reaction failed and a benzalfluorene oxide was obtained instead, noting that "reaction between the sulfur ylid and benzaldehydes did not afford benzalfluorenes as had the phosphorus and arsenic ylids."
The subsequent development of (dimethyloxosulfaniumyl)methanide
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https://en.wikipedia.org/wiki/Robert%20T.%20Siegel
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Robert T. Siegel (1928–2000) graduated from Carnegie Tech (now Carnegie Mellon University) in 1948, and attained a D.Sc in 1952. He was professor of physics at the College of William and Mary from 1963 to 1998, and director of the Space Radiation Effects Laboratory, located on the site where the Thomas Jefferson National Accelerator Facility would later be built, from its construction in 1964–65 to its decommissioning in 1980.
References
20th-century American physicists
1928 births
2000 deaths
College of William & Mary faculty
Fellows of the American Physical Society
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https://en.wikipedia.org/wiki/Pseudorandom%20generator%20theorem
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In computational complexity theory and cryptography, the existence of pseudorandom generators is related to the existence of one-way functions through a number of theorems, collectively referred to as the pseudorandom generator theorem.
Introduction
Pseudorandomness
A distribution is considered pseudorandom if no efficient computation can distinguish it from the true uniform distribution by a non-negligible advantage. Formally, a family of distributions Dn is pseudorandom if for any polynomial size circuit C, and any ε inversely polynomial in n
|Probx∈U [C(x)=1] − Probx∈D [C(x)=1] | ≤ ε.
Pseudorandom generators
A function Gl: {0,1}l → {0,1}m, where l < m is a pseudorandom generator if:
Gl can be computed in time polynomial in l
Gl(x) is pseudorandom, when x is uniformly random.
One additional pseudorandom bit implies polynomially more pseudorandom bits
It can be shown that if there is a pseudorandom generator Gl: {0,1}l → {0,1}l+1, i.e. a generator that adds only one pseudorandom bit, then for any m = poly(l), there is a pseudorandom generator G'l: {0,1}l → {0,1}m.
The idea of the proof is as follows: first s bits from uniform distribution Ul are picked and used as the seed to the first instance of Gl, which is known to be a pseudorandom generator. Next, the output of the first instance of Gl is divided into two parts: first l bits are fed into the second instance of Gl as a seed, while the last bit becomes the first bit of the output. Repeating this process for m ti
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https://en.wikipedia.org/wiki/Thioacetal
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In organosulfur chemistry, thioacetals are the sulfur (thio-) analogues of acetals (). There are two classes: the less-common monothioacetals, with the formula , and the dithioacetals, with the formula (symmetric dithioacetals) or (asymmetric dithioacetals).
The symmetric dithioacetals are relatively common. They are prepared by condensation of thiols () or dithiols (two groups) with aldehydes (). These reactions proceed via the intermediacy of hemithioacetals ():
Thiol addition to give hemithioacetal:
RSH + R'CH(O) -> R'CH(SR)OH
Thiol addition with loss of water to give dithioacetal:
RSH + R'CH(OH)SR -> R'CH(SR)2 + H2O
Such reactions typically employ either a Lewis acid or Brønsted acid as catalyst.
Dithioacetals generated from aldehydes and either 1,2-ethanedithiol or 1,3-propanedithiol are especially common among this class of molecules for use in organic synthesis.
The carbonyl carbon of an aldehyde is electrophilic and therefore susceptible to attack by nucleophiles, whereas the analogous central carbon of a dithioacetal is not electrophilic. As a result, dithioacetals can serve as protective groups for aldehydes.
Far from being unreactive, and in a reaction unlike that of aldehydes, that carbon can be deprotonated to render it nucleophilic:
R'CHS2C2H4 + R2NLi -> R'CLiS2C2H4 + R2NH
The inversion of polarity between and is referred to as umpolung. The reaction is commonly performed using the 1,3-dithiane. The lithiated intermediate can be used for various n
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https://en.wikipedia.org/wiki/2C-TFM
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2C-TFM is a psychedelic phenethylamine of the 2C family. It was first synthesized in the laboratory of David E. Nichols. It has also been called 2C-CF3, a name derived from the Para-trifluoromethyl group it contains.
Chemistry
2C-TFM is a code that represents 4-trifluoromethyl-2,5-dimethoxyphenethylamine. The full name of the chemical is 2-[2,5-dimethoxy-4-(trifluoromethyl)phenyl]ethanamine.
Dosage
A psychedelic dosage of 2C-TFM is reported to be 3–5 mg.
Effects
Very little data exists, but some reports suggest 2C-TFM produces psychedelic (hallucinogenic/entheogenic) effects that last between 5 and 7 hours. It is considered to be the strongest 2C variation.
Legality
United States
2C-TFM is unscheduled and uncontrolled in the United States, but possession and sales of 2C-TFM could potentially be prosecuted under the Federal Analog Act because of its structural similarities to 2C-B and 2C-T-7. However, 2C-TFM, unlike many other phenethylamines, has not been widely sold by internet retailers. In the wake of Operation Web Tryp in July 2004, the issue of possession and sales of 2C-TFM and other similar chemicals will probably be resolved in the courtroom as well the fate of this rare but unique psychedelic. There have been no reported deaths or hospitalizations from 2C-TFM.
Canada
As of October 31st, 2016, 2C-TFM is a controlled substance (Schedule III) in Canada.
Pharmacology
The mechanism that produces the hallucinogenic and entheogenic effects of 2C-TFM is most l
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https://en.wikipedia.org/wiki/K-vector
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In mathematics and physics, k-vector may refer to:
A wave vector k
Crystal momentum
A multivector of grade k, also called a k-vector, the dual of a differential k-form
An element of a k-dimensional vector space, especially a four-vector used in relativity to mean a quantity related to four-dimensional spacetime
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https://en.wikipedia.org/wiki/Middlebox
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A middlebox is a computer networking device that transforms, inspects, filters, and manipulates traffic for purposes other than packet forwarding. Examples of middleboxes include firewalls, network address translators (NATs), load balancers, and deep packet inspection (DPI) devices.
UCLA computer science professor Lixia Zhang coined the term middlebox in 1999.
Usage
Middleboxes are widely deployed across both private and public networks. Dedicated middlebox hardware is widely deployed in enterprise networks to improve network security and performance, however, even home network routers often have integrated firewall, NAT, or other middlebox functionality. One 2017 study counting more than 1,000 deployments in autonomous systems, in both directions of traffic flows, and across a wide range networks, including mobile operators and data center networks.
Examples
The following are examples of commonly deployed middleboxes:
Firewalls filter traffic based on a set of predefined security rules defined by a network administrator. IP firewalls reject packets "based purely on fields in the IP and transport headers (e.g., disallow incoming traffic to certain port numbers, disallow any traffic to certain subnets etc.)" Other types of firewalls may use more complex rulesets, including those that inspect traffic at the session or application layer.
Intrusion detection systems (IDSs) monitor traffic and collect data for offline analysis for security anomalies. Unlike firewalls, IDSs
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https://en.wikipedia.org/wiki/Sylwester%20Porowski
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Sylwester Andrzej Porowski (born April 7, 1938 in Bierzyn, Lower Silesian Voivodeship), is a Polish physicist specializing in solid-state and high pressure physics. He is the Co-Director and Board Member of The Institute of High Pressure Physics, Polish Academy of Sciences in Warsaw.
In 2001 Professor Porowski's team built the blue semiconductor laser, a pioneering feat in the study of optoelectronics.
Porowski was awarded Prize of the Foundation for Polish Science in 2013 for developing a high-pressure method for producing gallium nitride monocrystals.
References
External links
Unipress Website
1938 births
Living people
People from Strzelin
20th-century Polish physicists
University of Warsaw alumni
Polish inventors
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https://en.wikipedia.org/wiki/Wiktor%20Kemula
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Wiktor Kemula (born November 6, 1902 in Izmail – October 17, 1985 in Warsaw) was a Polish chemist, electrochemist, and polarographist. He greatly contributed to the development of electroanalytical chemistry, particularly polarography. He developed a hanging mercury drop electrode (HMDE).
1902 births
1985 deaths
People from Izmail
People from Izmailsky Uyezd
People from the Russian Empire of Polish descent
Polish chemists
University of Lviv alumni
Victims of post–World War II forced migrations
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https://en.wikipedia.org/wiki/Marceli%20Nencki
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Wilhelm Marceli Nencki (15 January 1847 in Boczki, Zduńska Wola County – 14 October 1901 in Saint Petersburg) was a Polish chemist and doctor.
Work
Nencki's main scientific interest concentrated on urea synthesis, the chemistry of purines and biological oxidation of aromatic compounds. He was also interested in the structure of proteins, enzymatic processes in the intestine and bacterial biochemistry. One of his achievements was for example demonstration that urea is formed in the organism from amino acids rather than being preformed on a protein molecule and that it is accompanied by binding of carbon dioxide.
He proposed that the synthesis of fatty acids proceeds stepwise, by a gradual condensation of two-carbon-atom fragments and that oxidation of fatty acids occurs by splitting into two-carbon units.
In 1877 while working at the University of Berne he discovered rhodanine via a reaction between ammonium rhodanide (in modern chemistry ammonium thiocyanate) and chloroacetic acid in water.
Among Nencki's greatest achievements was his study on the chemical structure of haemoglobin. He identified haemopyrrole among degradation products of haemoglobin and showed its identity with one of the products obtained by Leon Marchlewski from chlorophyll.
He was the first to rigorously analyze the cause of smell in urine following eating asparagus, which he attributed to methanethiol.
He made Phenyl salicylate or salol in 1886, and introduced it as a mild intestinal antiseptic (whi
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https://en.wikipedia.org/wiki/Centre%20for%20Mathematical%20Sciences%20%28Cambridge%29
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The Centre for Mathematical Sciences (CMS) at the University of Cambridge houses the university's Faculty of Mathematics, the Isaac Newton Institute, and the Betty and Gordon Moore Library. It is situated on Wilberforce Road, on a site which was formerly a St John's College playing field, and has been leased by St John's to the university as part of its expansion into West Cambridge.
The Isaac Newton Institute was opened in July 1992. Andrew Wiles announced his proof here of Fermat's Last Theorem on 23 June 1993, though it required additional fine tuning. The rest of the site was designed by Edward Cullinan architects and Buro Happold and construction under project manager Davis Langdon was completed in 2003. It consists of 340 offices in 7 'pavilions', arranged in a parabola around a 'central core' with lecture rooms, common space, and a grass-covered roof, as well as a gatehouse. The design won awards including the British Construction Industry Major Project Award 2003, the David Urwin Design Award 2003, the Royal Fine Art Commission Trust Specialist Award 2003 and the RIBA Award 2003.
Gallery
References
External links
Centre for Mathematical Sciences, University of Cambridge
Article by Jonathan Glancey in 'The Guardian',
Mathematical Sciences
Faculty of Mathematics, University of Cambridge
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https://en.wikipedia.org/wiki/Faculty%20of%20Mathematics%2C%20University%20of%20Cambridge
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The Faculty of Mathematics at the University of Cambridge comprises the Department of Pure Mathematics and Mathematical Statistics (DPMMS) and the Department of Applied Mathematics and Theoretical Physics (DAMTP). It is housed in the Centre for Mathematical Sciences site in West Cambridge, alongside the Isaac Newton Institute. Many distinguished mathematicians have been members of the faculty.
Some current members
DPMMS
Béla Bollobás
John Coates
Thomas Forster
Timothy Gowers
Peter Johnstone
Imre Leader
Gabriel Paternain
Statistical Laboratory
John Aston
Geoffrey Grimmett
Frank Kelly
Ioannis Kontoyiannis
Richard Nickl
James Norris
Richard Samworth
David Spiegelhalter
Richard Weber
DAMTP
Gary Gibbons
Julia Gog, professor of mathematical biology
Raymond E. Goldstein
Rich Kerswell
Paul Linden
Michael Green
Peter Haynes, fluid dynamicist
John Hinch, fluid dynamicist, retired 2014
Richard Jozsa
Hugh Osborn
John Papaloizou
Malcolm Perry
David Tong, theoretical physicist
Paul Townsend
Grae Worster, editor for the Journal of Fluid Mechanics
Mihaela van der Schaar
Carola-Bibiane Schönlieb
Pure Mathematics and Mathematical Statistics
The Department of Pure Mathematics and Mathematical Statistics (DPMMS) was created in 1964 under the headship of Sir William Hodge. It was housed in a converted warehouse at 16 Mill Lane, adjacent to its sister department DAMTP, until its move around 2000 to the present Centre for Mathematical Sciences where it occupies Pavilions C, D, and E.
Head
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https://en.wikipedia.org/wiki/Isadore%20Nabi
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Isadore Nabi (sometimes Isidore Nabi or Isador Nabi) was a pseudonym used by a group of scientists including Richard Lewontin, Richard Levins, Robert MacArthur, and Leigh van Valen in the 1960s. Inspired by the work of Nicolas Bourbaki, they allegedly hoped to create a unified approach to evolutionary biology. However, the project was aborted and the name was reused in the 1980s for satirical purposes.
Nabi's biography was listed in American Men and Women of Science, articles and letters were published in prominent journals under his name, and he was listed on the editorial board of Evolutionary Theory.
He has primarily written on sociobiology. His article, "An Evolutionary Interpretation of the English Sonnet" was delivered as the First Annual Piltdown Lecture on Man and Nature and appeared under the heading "Advances in Sociobiopsy". (The author was noted as a "Satirical Commentator".) He has also written articles critical of the systems-theoretical approach to mathematical ecology, as illustrated by what our laws of motion in physics would look like if early physicists had used the methods of the systems ecologists (this time listing the author as "Intrepid Investigator"). In 2002 he published a piece (under the name "Isador Nabi") on stock tips in Gene Watch. It was identified as humor.
Biography
His biography in American Men and Women of Science reads:
NABI, ISIDORE, b Brno, Czech, July 22, 10; m 30; c 6. POPULATION BIOLOGY. Educ: Cochabamba Univ, AB, 30; Nat Univ
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https://en.wikipedia.org/wiki/Colegio%20de%20Bi%C3%B3logos%20del%20Per%C3%BA
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Colegio de Biólogos del Perú or College of Biologists of Peru is a professional association in Peru. This college accepts only graduates in biology that have opted to be licensed through a special inter-university procedure called Licenciatura. It was founded in 1972 and its creation was sanctioned by Law.
According to Peruvian law, in order to work as a professional biologist one must be registered and be a dues-paying active member of the Colegio de Biólogos del Perú. It is governed by a National Dean or President, who is elected every two years by general elections, and presided over a National Council. The National Council is constituted by 18 Regional Councils. As of 2007 it had over 7,000 registered members nationwide; who must be active dues-paying members to exercise their right to vote. Regional Councils are headed by regional deans elected ( by popular vote in their respective circumscriptions) by biologists registered in those regions.
In 2006, Peruvian Congress passed Law 28847 that regulates the work of biologists and requires them to be duly registered in the Colegio de Biólogos del Perú in order to work for government, academia or the private world.
Past National Deans are Isabel Martos, Soledad Osorio, Sandro Chavez, Magdalena Pavlich, and Damisela Coz. The present National Dean is Ernesto Bustamante elected in April 2007 to serve the term 2007 - 2009.
See also
Education in Peru
References
External links
Website
Biology organizations
Professional ass
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https://en.wikipedia.org/wiki/Pioneer%20Academy
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Pioneer Academy is an independent college-preparatory school for PK-12 grades located in Wayne, in Passaic County, New Jersey, United States. The Pioneer Academy curriculum focuses on studies of science, mathematics, cultural studies, and language. The school was founded in 1999 and moved from Clifton to its Wayne campus at the start of the 2013-14 school year.
As of the 2019–20 school year, the school had an enrollment of 300 students (plus 23 in PreK) and 29.5 classroom teachers (on an FTE basis), for a student–teacher ratio of 10.2:1. The school's student body was 77.7% (233) White, 3% (9) Black, 14.3% (43) Asian, 2% (6) Hispanic and 2.7% (8) two or more races.
History
Pioneer is a co-educational day school for PreK-12 and a boys-only boarding school for high school students. The school is located in Wayne, New Jersey, about 30 minutes west of New York City.
1999 – Established as a middle school at 366 Clifton Avenue in Clifton, New Jersey
2006 – Opened second campus at 1255 Main Avenue in Clifton. Began catering to Pre-K through 12th grade
2008 – Gained I-20 issuing privileges
2009 – Started accepting international students
2011 – Became an all-boys high school. Remained co-ed middle school. The elementary school temporarily closed
2013 – Moved to 164 Totowa Road in Wayne, New Jersey, offering on-campus housing for students
2014 – Changed school name from Pioneer Academy of Science to Pioneer Academy
2014 - Became Co-ed Pre-K through 12th Grade
2017 - Pre-K Montessori
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https://en.wikipedia.org/wiki/Double%20descent
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In statistics and machine learning, double descent is the phenomenon where a statistical model with a small number of parameters and a model with an extremely large number of parameters have a small error, but a model whose number of parameters is about the same as the number of data points used to train the model will have a large error. It was discovered around 2018 when researchers were trying to reconcile the bias-variance tradeoff in classical statistics, which states that having too many parameters will yield an extremely large error, with the 2010s empirical observation of machine learning practitioners that the larger models are, the better they work. The scaling behavior of double descent has been found to follow a broken neural scaling law functional form.
References
Further reading
External links
Model selection
Machine learning
Statistical classification
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https://en.wikipedia.org/wiki/Phred
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Phred may refer to:
Phred (software), a computer program used in molecular biology
Phred quality score, a term used in molecular biology
Phred (Doonesbury), a character from the comic strip Doonesbury
Phred on Your Head Show, a children's television show
The URL with Phred Show, a spin-off of the above
See also
Fred (disambiguation)
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https://en.wikipedia.org/wiki/Fast%20folding%20algorithm
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In signal processing, the fast folding algorithm (Staelin, 1969) is an efficient algorithm for the detection of approximately-periodic events within time series data. It computes superpositions of the signal modulo various window sizes simultaneously.
The FFA is best known for its use in the detection of pulsars, as popularised by SETI@home and Astropulse.
It was also used by the Breakthrough Listen Initiative during their 2023 Investigation for Periodic Spectral Signals campaign.
See also
Pulsar
References
External links
The search for unknown pulsars
Signal processing
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https://en.wikipedia.org/wiki/Multifactor%20dimensionality%20reduction
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Multifactor dimensionality reduction (MDR) is a statistical approach, also used in machine learning automatic approaches, for detecting and characterizing combinations of attributes or independent variables that interact to influence a dependent or class variable. MDR was designed specifically to identify nonadditive interactions among discrete variables that influence a binary outcome and is considered a nonparametric and model-free alternative to traditional statistical methods such as logistic regression.
The basis of the MDR method is a constructive induction or feature engineering algorithm that converts two or more variables or attributes to a single attribute. This process of constructing a new attribute changes the representation space of the data. The end goal is to create or discover a representation that facilitates the detection of nonlinear or nonadditive interactions among the attributes such that prediction of the class variable is improved over that of the original representation of the data.
Illustrative example
Consider the following simple example using the exclusive OR (XOR) function. XOR is a logical operator that is commonly used in data mining and machine learning as an example of a function that is not linearly separable. The table below represents a simple dataset where the relationship between the attributes (X1 and X2) and the class variable (Y) is defined by the XOR function such that Y = X1 XOR X2.
Table 1
A machine learning algorithm would
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https://en.wikipedia.org/wiki/List%20of%20Jewish%20American%20computer%20scientists
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This is a list of notable Jewish American computer scientists. For other Jewish Americans, see Lists of Jewish Americans.
Hal Abelson, artificial intelligence
Leonard Adleman, RSA cryptography, DNA computing, Turing Award (2002)
Adi Shamir, RSA cryptography, DNA computing, Turing Award (2002)
Paul Baran, Polish-born engineer; co-invented packet switching
Lenore and Manuel Blum (Turing Award (1995)), Venezuelan-American computer scientist; computational complexity, parents of Avrim Blum (Co-training)
Dan Bricklin, creator of the original spreadsheet
Sergey Brin, co-founder of Google
Danny Cohen, Israeli-American Internet pioneer; first to run a visual flight simulator across the ARPANet
Robert Fano, Italian-American information theorist
Ed Feigenbaum, artificial intelligence, Turing Award (1994)
William F. Friedman, cryptologist
Herbert Gelernter, father of Unabomber victim David Gelernter;artificial intelligence
Richard D. Gitlin, co-inventor of the digital subscriber line (DSL)
Adele Goldberg, Smalltalk design team
Shafi Goldwasser, Israeli-American cryptographer; Turing Award (2013)
Philip Greenspun, web applications
Frank Heart, co-designed the first routing computer for the ARPANET, the forerunner of the internet
Martin Hellman, public key cryptography, co-inventor of the Diffie–Hellman key exchange protocol, Turing Award (2015)
Douglas Hofstadter, author of Gödel, Escher, Bach and other publications (half Jewish)
Bob Kahn, co-invented TCP and IP, P
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https://en.wikipedia.org/wiki/Alexander%20Bogomolny
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Alexander Bogomolny (January 4, 1948 July 7, 2018) was a Soviet-born Israeli-American mathematician. He was Professor Emeritus of Mathematics at the University of Iowa, and formerly research fellow at the Moscow Institute of Electronics and Mathematics, senior instructor at Hebrew University and software consultant at Ben Gurion University. He wrote extensively about arithmetic, probability, algebra, geometry, trigonometry and mathematical games.
He was known for his contribution to heuristics and mathematics education, creating and maintaining the mathematically themed educational website Cut-the-Knot for the Mathematical Association of America (MAA) Online. He was a pioneer in mathematical education on the internet, having started Cut-the-Knot in October 1996.
Education and academic career
Bogomolny attended Moscow school No. 444, for gifted children, then entered Moscow State University, where he graduated with a master's degree in mathematics in 1971. From 1971 to 1974 he was a junior research fellow at the Moscow Institute of Electronic Machine Building (MIEM). He emigrated to Israel and became a senior programmer at Lake Kinneret Research Laboratory in Tiberias, Israel (19741977) and a software consultant at Ben Gurion University in Negev, Be’er Sheva, Israel (19761977). From 1976 to 1983 he was a senior instructor and researcher at Hebrew University in Jerusalem. He received his Ph.D. in mathematics at Hebrew University in 1981. His dissertation is titled, A New
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https://en.wikipedia.org/wiki/Abel%27s%20identity
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In mathematics, Abel's identity (also called Abel's formula or Abel's differential equation identity) is an equation that expresses the Wronskian of two solutions of a homogeneous second-order linear ordinary differential equation in terms of a coefficient of the original differential equation.
The relation can be generalised to nth-order linear ordinary differential equations. The identity is named after the Norwegian mathematician Niels Henrik Abel.
Since Abel's identity relates to the different linearly independent solutions of the differential equation, it can be used to find one solution from the other. It provides useful identities relating the solutions, and is also useful as a part of other techniques such as the method of variation of parameters. It is especially useful for equations such as Bessel's equation where the solutions do not have a simple analytical form, because in such cases the Wronskian is difficult to compute directly.
A generalisation of first-order systems of homogeneous linear differential equations is given by Liouville's formula.
Statement
Consider a homogeneous linear second-order ordinary differential equation
on an interval I of the real line with real- or complex-valued continuous functions p and q. Abel's identity states that the Wronskian of two real- or complex-valued solutions and of this differential equation, that is the function defined by the determinant
satisfies the relation
for each point .
Remarks
In particular
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https://en.wikipedia.org/wiki/2C-B-FLY
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2C-B-FLY is a psychedelic phenethylamine and designer drug of the 2C family. It was first synthesized in 1996 by Aaron Monte, Professor of Chemistry at UW-La Crosse.
Chemistry
2C-B-FLY is 8-bromo-2,3,6,7-benzo-dihydro-difuran-ethylamine. The full name of the chemical is 2-(8-bromo-2,3,6,7-tetrahydrofuro[2,3-f] [1]benzofuran-4-yl)ethanamine. It has been subject of little formal study, but its appearance as a designer drug has led the DEA to release analytical results for 2C-B-FLY and several related compounds.
Analogs and derivatives
In theory, dihydro-difuran analogs of any of the 2Cx / DOx family of drugs could be made, and would be expected to show similar activity to the parent compounds, 2-CB, DOB, DOM, etc. In practice, it was found that 2C-B-FLY was approximately 10x more potent than the parent drug, 2C-B ("Nexus," "bromo," "afterburner bromo," "utopia", "Venus," "spectrum," BDMPEA, "toonies," MFT, "erox," "cloud nine," "zenithetic," etc.), and superior in its pharmacological effects in large mammals. So, in the same way that 2C-B-FLY is the dihydro-difuran analog of 2C-B, the 8-iodo equivalent, "2C-I-FLY," would be the dihydro-difuran analogue of 2C-I, and the 8-methyl equivalent, "2C-D-FLY," would be the dihydro-difuran analogue of 2C-D.
Other related compounds can also be imagined and produced in which the alpha carbon of the ethylamine sidechain is methylated, giving the amphetamine derivative DOB-FLY, with this compound being the dihydro-difuran analogue of
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https://en.wikipedia.org/wiki/Metallome
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In biochemistry, the metallome is the distribution of metal ions in a cellular compartment. The term was coined in analogy with proteome as metallomics is the study of metallome: the "comprehensive analysis of the entirety of metal and metalloid species within a cell or tissue type". Therefore, metallomics can be considered a branch of metabolomics, even though the metals are not typically considered as metabolites.
An alternative definition of "metallomes" as metalloproteins or any other metal-containing biomolecules, and "metallomics" as a study of such biomolecules.
Metallointeractome
In the study of metallomes the transcriptome, proteome and the metabolome constitutes the whole metallome. A study of the metallome is done to arrive at the metallointeractome.
Metallotranscriptome
The metallotranscriptome can be defined as the map of the entire transcriptome in the presence of biologically or environmentally relevant concentrations of an essential or toxic metal, respectively. The metallometabolome constitutes the complete pool of small metabolites in a cell at any given time. This gives rise to the whole metallointeractome and knowledge of this is important in comparative metallomics dealing with toxicity and drug discovery.
See also
Bioinorganic chemistry
-omics
References
Sources
electronic-book electronic-
Systems biology
Metabolism
Bioinformatics
Biochemistry methods
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https://en.wikipedia.org/wiki/CPK%20coloring
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In chemistry, the CPK coloring (for Corey–Pauling–Koltun) is a popular color convention for distinguishing atoms of different chemical elements in molecular models.
History
August Wilhelm von Hofmann was apparently the first to introduce molecular models into organic chemistry, following August Kekule's introduction of the theory of chemical structure in 1858, and Alexander Crum Brown's introduction of printed structural formulas in 1861. At a Friday Evening Discourse at London's Royal Institution on April 7, 1865, he displayed molecular models of simple organic substances such as methane, ethane, and methyl chloride, which he had had constructed from differently colored table croquet balls connected together with thin brass tubes. Hofmann's original colour scheme (carbon = black, hydrogen = white, nitrogen = blue, oxygen = red, chlorine = green, and sulphur = yellow) has evolved into the later color schemes.
In 1952, Corey and Pauling published a description of space-filling models of proteins and other biomolecules that they had been building at Caltech. Their models represented atoms by faceted hardwood balls, painted in different bright colors to indicate the respective chemical elements. Their color schema included
White for hydrogen
Black for carbon
Sky blue for nitrogen
Red for oxygen
They also built smaller models using plastic balls with the same color schema.
In 1965 Koltun patented an improved version of the Corey and Pauling modeling technique. In his pa
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https://en.wikipedia.org/wiki/Istituto%20di%20Radioastronomia%20di%20Bologna
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The Istituto di Radioastronomia di Bologna (Institute for Radio Astronomy of Bologna) is one of research facilities of the Italian Istituto Nazionale di Astrofisica (National Institute for Astrophysics). Staff conduct research in astronomy, physics, engineering and information science. It was previously part of the Consiglio Nazionale delle Ricerche (CNR; National Research Council).
The institute manages three instruments: two parabolic aerials built by CNR and the radio telescope Croce del Nord (Northern Cross) built by the University of Bologna and inaugurated in 1964.
The institute also operates on:
the Medicina Radio Observatory and the VLBI aerial in Medicina, Emilia-Romagna.
the Noto Radio Observatory in Noto, Sicily
The Sardinia Radio Telescope (SRT) in Sardinia.
References
External links
Official page
Research institutes in Italy
Radio astronomy
Radio telescopes
Interferometry
Observational astronomy
Astronomy institutes and departments
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https://en.wikipedia.org/wiki/List%20of%20EC%20numbers%20%28EC%201%29
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This list contains a list of EC numbers for the first group, EC 1, oxidoreductases, placed in numerical order as determined by the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology. All official information is tabulated at the website of the committee. The database is developed and maintained by Andrew McDonald.
EC 1.1 Acting on the CH-OH group of donors
EC 1.1.1 With Nicotinamide adenine dinucleotide or NADP as acceptor
: alcohol dehydrogenase
: alcohol dehydrogenase (NADP+)
: homoserine dehydrogenase
: (R,R)-butanediol dehydrogenase
EC 1.1.1.5: acetoin dehydrogenase. Now EC 1.1.1.303, diacetyl reductase [(R)-acetoin forming] and EC 1.1.1.304, diacetyl reductase [(S)-acetoin forming]
: glycerol dehydrogenase
: propanediol-phosphate dehydrogenase
: glycerol-3-phosphate dehydrogenase (NAD+)
: D-xylulose reductase
: L-xylulose reductase
: D-arabinitol 4-dehydrogenase
: L-arabinitol 4-dehydrogenase
: L-arabinitol 2-dehydrogenase
: L-iditol 2-dehydrogenase
: D-iditol 2-dehydrogenase
: galactitol 2-dehydrogenase
: mannitol-1-phosphate 5-dehydrogenase
: inositol 2-dehydrogenase
: glucuronate reductase
: glucuronolactone reductase
: (-)-menthol dehydrogenase
: (+)-neomenthol dehydrogenase
: aldose reductase
: UDP-glucose 6-dehydrogenase
: (R)-4-hydroxyphenyllactate dehydrogenase
: histidinol dehydrogenase|
: quinate/shikimate dehydrogenase (NAD+)
: shikimate dehydrogenase (NADP+)
: glyoxylate reductase
: L-lactate dehydrogenase
: D-lactat
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https://en.wikipedia.org/wiki/British%20Mathematical%20Olympiad
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The British Mathematical Olympiad (BMO) forms part of the selection process for the UK International Mathematical Olympiad team and for other international maths competitions, including the European Girls' Mathematical Olympiad, the Romanian Master of Mathematics and Sciences, and the Balkan Mathematical Olympiad. It is organised by the British Mathematical Olympiad Subtrust, which is part of the United Kingdom Mathematics Trust. There are two rounds, the BMO1 and the BMO2.
BMO Round 1
The first round of the BMO is held in November each year, and from 2006 is an open entry competition. The qualification to BMO Round 1 is through the Senior Mathematical Challenge. Students who do not make the qualification through the Senior Mathematical Challenge may be entered at the discretion of their school for a fee of £40.
The paper lasts 3½ hours, and consists of six questions (from 2005), each worth 10 marks. The exam in the 2020-2021 cycle was adjusted to consist of two sections, first section with 4 questions each worth 5 marks (only answers required), and second section with 3 question each worth 10 marks (full solutions required). The duration of the exam had been reduced to 2½ hours, due to the difficulties of holding a 3½ hours exam under COVID-19.
Candidates are required to write full proofs to the questions. An answer is marked on either a "0+" or a "10-" mark scheme, depending on whether the answer looks generally complete or not. An answer judged incomplete or unfinished
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https://en.wikipedia.org/wiki/John%20E.%20L.%20Peck
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John Edward Lancelot Peck (14 August 1918 – 6 November 2013) was the first permanent Head of Department of Computer Science at the University of British Columbia (UBC). He remained the Head of Department from 1969 to 1977.
He was one of the editors of the original Report on the Algorithmic Language ALGOL 68 and a contributing editor to the Revised Report on the Algorithmic Language ALGOL 68. He has written an article outlining his personal account of being part of the design team. Before assuming his role as the Head of Computer Science at the University of British Columbia, he was the first Head of the University of Calgary's newly built Math Department.
Many of his publications are indexed on the DBLP computer science bibliography site, and the Computer History Museum, software preservation group site.
Early years
John spent his early years in South Africa receiving a Bachelor of Science (B.Sc.) in Mathematics and Physics at the University of Natal, South Africa, after which he received a Master of Science (M.Sc.) in mathematics. His first teaching position was lecturing in mathematics. In 1946, he took a scholarship to Yale University, where he obtained a Doctor of Philosophy (Ph.D.) in 1950, with a thesis on the topological semigroups. He then went on to teach at Brown University for three years before returning to the University of Natal. In 1955, he emigrate to Canada and taught at the University of New Brunswick followed by four years at McGill University. He left M
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https://en.wikipedia.org/wiki/Directional%20symmetry%20%28time%20series%29
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In statistical analysis of time series and in signal processing, directional symmetry is a statistical measure of a model's performance in predicting the direction of change, positive or negative, of a time series from one time period to the next.
Definition
Given a time series with values at times and a model that makes predictions for those values , then the directional symmetry (DS) statistic is defined as
Interpretation
The DS statistic gives the percentage of occurrences in which the sign of the change in value from one time period to the next is the same for both the actual and predicted time series. The DS statistic is a measure of the performance of a model in predicting the direction of value changes. The case would indicate that a model perfectly predicts the direction of change of a time series from one time period to the next.
See also
Statistical finance
Notes and references
Drossu, Radu, and Zoran Obradovic. "INFFC data analysis: lower bounds and testbed design recommendations." Computational Intelligence for Financial Engineering (CIFEr), 1997., Proceedings of the IEEE/IAFE 1997. IEEE, 1997.
Lawrance, A. J., "Directionality and Reversibility in Time Series", International Statistical Review, 59 (1991), 67–79.
Tay, Francis EH, and Lijuan Cao. "Application of support vector machines in financial time series forecasting." Omega 29.4 (2001): 309–317.
Xiong, Tao, Yukun Bao, and Zhongyi Hu. "Beyond one-step-ahead forecasting: Evaluation of alternative mu
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https://en.wikipedia.org/wiki/Dmitry%20Belyayev%20%28zoologist%29
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Dmitry Konstantinovich Belyayev (Russian: Дми́трий Константи́нович Беля́ев, 17 July 1917 – 14 November 1985) was a Soviet geneticist and academician who served as director of the Institute of Cytology and Genetics (IC&G) of the USSR Academy of Sciences, Novosibirsk, from 1959 to 1985. His decades-long effort to breed domesticated silver foxes was described by The New York Times as “arguably the most extraordinary breeding experiment ever conducted.” A 2010 article in Scientific American stated that Belyayev “may be the man most responsible for our understanding of the process by which wolves were domesticated into our canine companions.”
Beginning in the 1950s, in order to uncover the genetic basis of the distinctive behavioral and physiological attributes of domesticated animals, Belyayev and his team spent decades breeding the silver fox (Vulpes vulpes) and selecting for reproduction only those individuals in each generation that showed the least fear of humans. After several generations of controlled breeding, a majority of the silver foxes no longer showed any fear of humans and often wagged their tails and licked their human caretakers to show affection. They also began to display spotted coats, floppy ears, curled tails, as well as other physical attributes often found in domesticated animals, thus confirming Belyayev’s hypothesis that both the behavioral and physical traits of domesticated animals could be traced to "a collection of genes that conferred a propensity
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https://en.wikipedia.org/wiki/P%C3%A9pin%27s%20test
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In mathematics, Pépin's test is a primality test, which can be used to determine whether a Fermat number is prime. It is a variant of Proth's test. The test is named for a French mathematician, Théophile Pépin.
Description of the test
Let be the nth Fermat number. Pépin's test states that for n > 0,
is prime if and only if
The expression can be evaluated modulo by repeated squaring. This makes the test a fast polynomial-time algorithm. However, Fermat numbers grow so rapidly that only a handful of Fermat numbers can be tested in a reasonable amount of time and space.
Other bases may be used in place of 3. These bases are:
3, 5, 6, 7, 10, 12, 14, 20, 24, 27, 28, 39, 40, 41, 45, 48, 51, 54, 56, 63, 65, 75, 78, 80, 82, 85, 90, 91, 96, 102, 105, 108, 112, 119, 125, 126, 130, 147, 150, 156, 160, ... .
The primes in the above sequence are called Elite primes, they are:
3, 5, 7, 41, 15361, 23041, 26881, 61441, 87041, 163841, 544001, 604801, 6684673, 14172161, 159318017, 446960641, 1151139841, 3208642561, 38126223361, 108905103361, 171727482881, 318093312001, 443069456129, 912680550401, ...
For integer b > 1, base b may be used if and only if only a finite number of Fermat numbers Fn satisfies that , where is the Jacobi symbol.
In fact, Pépin's test is the same as the Euler-Jacobi test for Fermat numbers, since the Jacobi symbol is −1, i.e. there are no Fermat numbers which are Euler-Jacobi pseudoprimes to these bases listed above.
Proof of correctness
Sufficiency: a
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https://en.wikipedia.org/wiki/Complex%20modulus
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Complex modulus may refer to:
Modulus of complex number, in mathematics, the norm or absolute value, of a complex number:
Dynamic modulus, in materials engineering, the ratio of stress to strain under vibratory conditions
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https://en.wikipedia.org/wiki/Jagjit%20Singh%20%28writer%29
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Jagjit Singh (1912–2002) was an Indian writer and science popularizer. In college he excelled in mathematics courses, receiving his MA in Mathematics from the Government College, Lahore. Yet he made his career as an important director of India's railways, applying his mathematical skills there. Upon retirement, he set out in writing several books, starting with Great Ideas of Modern Mathematics, popularizing science and targeting laymen. Singh subsequently won the Kalinga Prize from UNESCO in 1963, being the first Indian and Asian to do so.
In 1960, he was appointed director of the Indian Railways Board, and nine years later he was appointed general manager of the Northeast Frontier Railway. After his retirement he went to work as managing director of the Indian Drugs and Pharmaceuticals, adviser of Asian Development Bank and adviser of Tata Chemicals.
Singh was elected a Fellow of the Royal Statistical Society of London, and was President of the Operational Society of India and a member of the Indian Statistical Institute. He was awarded an honorary Doctorate in Science in 1968 by Roorkee University. He was also chosen by Pakistan scientist and Nobel Prize winner in Physics in 1979, Abdus Salam to write his biography, which came out in 1992 published by Penguin books.
Some works
Mathematical Ideas: Their Nature and Use (1959)
Great Ideas of Modern Mathematics
Great Ideas and Theories of Modern Cosmology
Great Ideas in Information Theory, Language and Cybernetics
R
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https://en.wikipedia.org/wiki/Music%20Genome%20Project
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The Music Genome Project is an effort to "capture the essence of music at the most fundamental level" using various attributes to describe songs and mathematics to connect them together into an interactive map. The Music Genome Project covers five music genres: Pop/Rock, Hip-Hop/Electronica, Jazz, World Music, and Classical.
Any given song is represented by approximately 450 "genes" (analogous to trait-determining genes for organisms in the field of genetics). Each gene corresponds to a characteristic of the music, for example, gender of lead vocalist, prevalent use of groove, level of distortion on the electric guitar, type of background vocals, etc. Rock and pop songs have 150 genes, rap songs have 350, and jazz songs have approximately 400. Other genres of music, such as world and classical music, have 300–450 genes. The system depends on a sufficient number of genes to render useful results. Each gene is assigned a number between 0 and 5, in half-integer increments. The Music Genome Project's database is built using a methodology that includes the use of precisely defined terminology, a consistent frame of reference, redundant analysis, and ongoing quality control to ensure that data integrity remains reliably high.
Given the vector of one or more songs, a list of other similar songs is constructed using what the company calls its "matching algorithm". Each song is analyzed by a musician in a process that takes 20 to 30 minutes per song. Ten percent of songs are analyze
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https://en.wikipedia.org/wiki/Transporter%20Classification%20Database
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The Transporter Classification Database (or TCDB) is an International Union of Biochemistry and Molecular Biology (IUBMB)-approved classification system for membrane transport proteins, including ion channels.
Classification
The upper level of classification and a few examples of proteins with known 3D structure:
1. Channels and pores
1.A α-type channels
1.A.1 Voltage-gated ion channel superfamily
1.A.2 Inward-rectifier K+ channel family
1.A.3 Ryanodine-inositol-1,4,5-trisphosphate receptor Ca2+ channel family
1.A.4 Transient receptor potential Ca2+ channel family
1.A.5 Polycystin cation channel family
1.A.6 Epithelial Na+ channel family
1.A.7 ATP-gated P2X receptor cation channel family
1.A.8 Major intrinsic protein superfamily
1.A.9 Neurotransmitter receptor, Cys loop, ligand-gated ion channel family
1.A.10 Glutamate-gated ion channel family of neurotransmitter receptors
1.A.11 Ammonium channel transporter family
1.A.12 Intracellular chloride channel family
1.A.13 Epithelial chloride channel family
1.A.14 Testis-enhanced gene transfer family
1.A.15 Nonselective cation channel-2 family
1.A.16 Formate-nitrite transporter family
1.A.17 Calcium-dependent chloride channel family
1.A.18 Chloroplast envelope anion-channel-forming Tic110 family
1.A.19 Type A influenza virus matrix-2 channel family
1.A.20 BCL2/Adenovirus E1B-interacting protein 3 family
1.A.21 Bcl-2 family
1.A.22 Large-conductance mechanosensitive ion channel
1.A.23 Small-conductance mechan
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https://en.wikipedia.org/wiki/Alfred%20de%20Rothschild
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Alfred Charles Freiherr de Rothschild, CVO (20 July 1842 – 31 January 1918), was the second son of Lionel Freiherr de Rothschild and Charlotte Freifrau von Rothschild of the Rothschild family.
Education
As a young man, Alfred attended King's College School, Wimbledon, and subsequently Trinity College, Cambridge, where he would study Mathematics for two terms. It was at Trinity College that Alfred formed a lasting friendship with the Prince of Wales, later King Edward VII. Alfred left Cambridge University without a degree.
Banking career
At the age of 21, Alfred took up employment at the N.M. Rothschild Bank at New Court in London. It was there that he learnt the business of banking from his father and made valuable contacts in European banking circles.
In 1868, at the age of 26, Alfred became a director of the Bank of England, a post he held for 20 years, until 1889. In 1892, he represented the British Government at the International Monetary Conference in Brussels.
His career at the Bank of England was described in The Rothschilds: A Family of Fortune, by Virginia Cowles:
Alfred was not only a partner at New Court but a Director of the Bank of England, an appointment he had been given in 1868 because the Governor felt it would not be a bad thing to keep in close touch with the Rothschilds. The relationship came to an abrupt end of 1889, however, over a slightly unorthodox situation. Alfred had paid a very high price for a French eighteenth-century painting after being a
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https://en.wikipedia.org/wiki/Partition%20problem
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In number theory and computer science, the partition problem, or number partitioning, is the task of deciding whether a given multiset S of positive integers can be partitioned into two subsets S1 and S2 such that the sum of the numbers in S1 equals the sum of the numbers in S2. Although the partition problem is NP-complete, there is a pseudo-polynomial time dynamic programming solution, and there are heuristics that solve the problem in many instances, either optimally or approximately. For this reason, it has been called "the easiest hard problem".
There is an optimization version of the partition problem, which is to partition the multiset S into two subsets S1, S2 such that the difference between the sum of elements in S1 and the sum of elements in S2 is minimized. The optimization version is NP-hard, but can be solved efficiently in practice.
The partition problem is a special case of two related problems:
In the subset sum problem, the goal is to find a subset of S whose sum is a certain target number T given as input (the partition problem is the special case in which T is half the sum of S).
In multiway number partitioning, there is an integer parameter k, and the goal is to decide whether S can be partitioned into k subsets of equal sum (the partition problem is the special case in which k = 2).
However, it is quite different than the 3-partition problem: in that problem, the number of subsets is not fixed in advance – it should be |S|/3, where each subset mus
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https://en.wikipedia.org/wiki/Ethylisopropyltryptamine
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Ethylisopropyltryptamine (EiPT) is a chemical of the tryptamine family that and produces psychedelic and hallucinogenic effects. It was probably first synthesized by American psychopharmacologist, Alexander Shulgin.
Chemistry
EiPT is short for N-ethyl-N-isopropyl-tryptamine. The full chemical name of this structure is N-ethyl-N-[2-(1H-indol-3-yl)ethyl]propan-2-amine. EiPT is a tryptamine, which all belong to a larger family of compounds known as indolethylamines. EiPT is closely related to the compounds diethyltryptamine (DET) and DIPT.
Dosage
In his book TiHKAL, Alexander Shulgin lists a dosage for EiPT as being 24-40 mg taken orally.
Effects
Very little is known about the psychopharmacological properties of EiPT, but reports suggest it produces psychedelic effects that can last 4–6 hours. According to Shulgin, this compound tends to produce nausea, dysphoria, and other unpleasant side-effects. It also lacks the hallucinatory and visual properties usually associated with psychedelic drugs.
Dangers
There have been no reported deaths or hospitalizations from EiPT, but its safety profile is unknown.
Legality
EiPT is unscheduled and uncontrolled in the United States, but possession and sales of EiPT could be prosecuted under the Federal Analog Act because of its structural similarities to DET.
See also
5-MeO-EiPT
External links
EiPT entry from TiHKAL
EiPT entry in TiHKAL • info
Psychedelic tryptamines
Designer drugs
Isopropylamino compounds
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https://en.wikipedia.org/wiki/Technical%20Information%20Project
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The Technical Information Project (TIP) was an early database project focused on the scholarly physics literature. Its "most unique feature" was its use bibliographic coupling, a novel way to search for related documents. The TIP included over 25,000 records.
Meyer Mike Kessler began developing the TIP at MIT in April 1962, with the support of a grant by the National Science Foundation. The project's objective was to create a system that could "perform automatic search operations on bibliographic data" using bibliographic coupling. Some of the innovations in TIP included the use of wild cards, and boolean searching.
Transfer to the American Institute of Physics
Around 1968, responsibility for the TIP was transferred to the American Institute of Physics, under the direction of Dr. H. William Koch. In connection with the transfer, the Institute received a $149,000 NSF grant meant to address problems "produced by the rapid growth of the published [physics] literature, which threatens a breakdown in communications among scientists". The Institute aimed to create a nationwide "physics information network" by adding indexing information to the TIP, and using it to automatically produce classification indexes for its 38 physics journals, as part of a planned "National Physics Information System".
References
Not cited inline
Chronology of Information Science
Bourne, C.P. and Hahn, T. B. A History of Online Information Services, 1963-1976. Cambridge, MA: MIT Press, 2003.
The
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https://en.wikipedia.org/wiki/Gast%C3%B3n%20Pons%20Muzzo
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Gastón Pons Muzzo (circa 1922 – January 6, 2004) was a Peruvian chemist.
He was born in Tacna, Peru and joined National University of San Marcos staff in the 1960s to lecture general chemistry laboratory at the Department of Chemistry. He also was known for his teaching of physical chemistry and for his accompanying textbook. He was elected as dean in 1964 and remained in office until 1967.
He was elected as president of Chemical Society of Peru between 1974 and 1977 and was rector magnificus of the university. In 1985, when his term ended, he was awarded by then Peru's official secretary of treasury, Miguel Ángel Cusiánovich, in recognition of his role as rector.
Before his retirement from National University of San Marcos, he was appointed to another term in Peru's chemical society from 1988 to 1989. During the late 1990s, he was elected president of the commission which eventually established "María Inmaculada de Magdalena University", but health problems led him retire. He died on January 6, 2004, in Lima, Peru at the age of 81.
1920s births
2004 deaths
Peruvian chemists
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https://en.wikipedia.org/wiki/History%20of%20computer%20science
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The history of computer science began long before the modern discipline of computer science, usually appearing in forms like mathematics or physics. Developments in previous centuries alluded to the discipline that we now know as computer science. This progression, from mechanical inventions and mathematical theories towards modern computer concepts and machines, led to the development of a major academic field, massive technological advancement across the Western world, and the basis of a massive worldwide trade and culture.
Prehistory
The earliest known tool for use in computation was the abacus, developed in the period between 2700 and 2300 BCE in Sumer. The Sumerians' abacus consisted of a table of successive columns which delimited the successive orders of magnitude of their sexagesimal number system. Its original style of usage was by lines drawn in sand with pebbles. Abaci of a more modern design are still used as calculation tools today, such as the Chinese abacus.
In the 5th century BC in ancient India, the grammarian Pāṇini formulated the grammar of Sanskrit in 3959 rules known as the Ashtadhyayi which was highly systematized and technical. Panini used metarules, transformations and recursions.
The Antikythera mechanism is believed to be an early mechanical analog computer. It was designed to calculate astronomical positions. It was discovered in 1901 in the Antikythera wreck off the Greek island of Antikythera, between Kythera and Crete, and has been dated to
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https://en.wikipedia.org/wiki/2%2C4%2C5-Trimethoxyphenethylamine
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2,4,5-Trimethoxyphenethylamine (2C-O or 2C-OMe) or is a phenethylamine of the 2C family and was first synthesized by Jansen in 1931. It is a positional isomer of the drug mescaline (3,4,5-trimethoxy).
Chemistry
2C-O is a member of a class of chemical compounds commonly known as phenethylamines. Its full chemical name is 2-(2,4,5-trimethoxyphenyl)ethanamine; it is also known as 2,4,5-trimethoxyphenethylamine and 2,4,5-TMPEA.
Effects
Although not centrally active itself, 2C-O appeared to potentiate the action of mescaline when employed as pretreatment 45 minutes prior to the administration of mescaline.
Dangers
The toxicity of 2C-O is not known.
Law
Canada
As of October 31, 2016, 2C-O is a controlled substance (Schedule III) in Canada.
United States
2C-O is a Schedule I substance, as a positional isomer of mescaline.
United Kingdom
2C-O and all other compounds featured in PiHKAL are Class A drugs in the United Kingdom.
References
External links
2C-O Entry in PiHKAL
TMPEA Entry in PiHKAL • info
2C (psychedelics)
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https://en.wikipedia.org/wiki/History%20of%20chemical%20engineering
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Chemical engineering is a discipline that was developed out of those practicing "industrial chemistry" in the late 19th century. Before the Industrial Revolution (18th century), industrial chemicals and other consumer products such as soap were mainly produced through batch processing. Batch processing is labour-intensive and individuals mix predetermined amounts of ingredients in a vessel, heat, cool or pressurize the mixture for a predetermined length of time. The product may then be isolated, purified and tested to achieve a saleable product. Batch processes are still performed today on higher value products, such as pharmaceutical intermediates, speciality and formulated products such as perfumes and paints, or in food manufacture such as pure maple syrups, where a profit can still be made despite batch methods being slower and inefficient in terms of labour and equipment usage. Due to the application of Chemical Engineering techniques during manufacturing process development, larger volume chemicals are now produced through continuous "assembly line" chemical processes. The Industrial Revolution was when a shift from batch to more continuous processing began to occur. Today commodity chemicals and petrochemicals are predominantly made using continuous manufacturing processes whereas speciality chemicals, fine chemicals and pharmaceuticals are made using batch processes.
Origin
The Industrial Revolution led to an unprecedented escalation in demand, both with regard to
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https://en.wikipedia.org/wiki/David%20Orme%20Masson
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Sir David Orme Masson KBE FRS FRSE (13 January 1858 – 10 August 1937) was a scientist born in England who emigrated to Australia to become Professor of Chemistry at the University of Melbourne. He is known for his work on the explosive compound nitroglycerin.
Early life
Masson was born in Hampstead (near London), the only son and second child of English suffragist Emily Rosaline Orme and her husband, David Mather Masson, Professor of English Literature at University College London. His father later became Professor of Rhetoric and English Literature at the University of Edinburgh in 1865.
Masson was educated at Oliphant's School in Edinburgh (1865–68), the Edinburgh Academy and then the University of Edinburgh, where he graduated MA in 1877. He studied chemistry under Alexander Crum Brown. He then studied under Friedrich Wöhler at Göttingen in 1879 before obtaining a position with William Ramsay at Bristol, with whom he did research work on phosphorus. Masson returned to the University of Edinburgh in 1881 with a Research Scholarship for three years, obtaining his DSc degree in 1884. Masson was involved in the founding of the Student Representative Council. His research during this period included investigations in the preparation and properties of nitroglycerin (glyceryl trinitrate).
In 1885 he was elected a Fellow of the Royal Society of Edinburgh. His proposers were Alexander Crum Brown, Arthur Mitchell, John Murray, and Peter Guthrie Tait.
On 5 August 1886, Masson mar
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https://en.wikipedia.org/wiki/Learning%20automaton
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A learning automaton is one type of machine learning algorithm studied since 1970s. Learning automata select their current action based on past experiences from the environment. It will fall into the range of reinforcement learning if the environment is stochastic and a Markov decision process (MDP) is used.
History
Research in learning automata can be traced back to the work of Michael Lvovitch Tsetlin in the early 1960s in the Soviet Union. Together with some colleagues, he published a collection of papers on how to use matrices to describe automata functions. Additionally, Tsetlin worked on reasonable and collective automata behaviour, and on automata games. Learning automata were also investigated by researches in the United States in the 1960s. However, the term learning automaton was not used until Narendra and Thathachar introduced it in a survey paper in 1974.
Definition
A learning automaton is an adaptive decision-making unit situated in a random environment that learns the optimal action through repeated interactions with its environment. The actions are chosen according to a specific probability distribution which is updated based on the environment response the automaton obtains by performing a particular action.
With respect to the field of reinforcement learning, learning automata are characterized as policy iterators. In contrast to other reinforcement learners, policy iterators directly manipulate the policy π. Another example for policy iterators are evo
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