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https://en.wikipedia.org/wiki/Electron%20donor
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In chemistry, an electron donor is a chemical entity that donates electrons to another compound. It is a reducing agent that, by virtue of its donating electrons, is itself oxidized in the process.
Typical reducing agents undergo permanent chemical alteration through covalent or ionic reaction chemistry. This results in the complete and irreversible transfer of one or more electrons. However, in many chemical circumstances, the transfer of electronic charge to an electron acceptor may be only fractional. The electron is not completely transferred, which results in an electron resonance between the donor and acceptor. This leads to the formation of charge transfer complexes, in which the components largely retain their chemical identities.
The electron donating power of a donor molecule is measured by its ionization potential which is the energy required to remove an electron from the highest occupied molecular orbital (HOMO).
The overall energy balance (ΔE), i.e., energy gained or lost, in an electron donor-acceptor transfer is determined by the difference between the acceptor's electron affinity (A) and the ionization potential (I):
The class of electron donors that donate not just one, but a set of two paired electrons that form a covalent bond with an electron acceptor molecule, is known as a Lewis base. This phenomenon gives rise to the wide field of Lewis acid-base chemistry. The driving forces for electron donor and acceptor behavior in chemistry is based on the con
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https://en.wikipedia.org/wiki/Jet%20group
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In mathematics, a jet group is a generalization of the general linear group which applies to Taylor polynomials instead of vectors at a point. A jet group is a group of jets that describes how a Taylor polynomial transforms under changes of coordinate systems (or, equivalently, diffeomorphisms).
Overview
The k-th order jet group Gnk consists of jets of smooth diffeomorphisms φ: Rn → Rn such that φ(0)=0.
The following is a more precise definition of the jet group.
Let k ≥ 2. The differential of a function f: Rk → R can be interpreted as a section of the cotangent bundle of RK given by df: Rk → T*Rk. Similarly, derivatives of order up to m are sections of the jet bundle Jm(Rk) = Rk × W, where
Here R* is the dual vector space to R, and Si denotes the i-th symmetric power. A smooth function f: Rk → R has a prolongation jmf: Rk → Jm(Rk) defined at each point p ∈ Rk by placing the i-th partials of f at p in the Si((R*)k) component of W.
Consider a point . There is a unique polynomial fp in k variables and of order m such that p is in the image of jmfp. That is, . The differential data x′ may be transferred to lie over another point y ∈ Rn as jmfp(y) , the partials of fp over y.
Provide Jm(Rn) with a group structure by taking
With this group structure, Jm(Rn) is a Carnot group of class m + 1.
Because of the properties of jets under function composition, Gnk is a Lie group. The jet group is a semidirect product of the general linear group and a connected, simply connected
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https://en.wikipedia.org/wiki/Lamb%E2%80%93Oseen%20vortex
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In fluid dynamics, the Lamb–Oseen vortex models a line vortex that decays due to viscosity. This vortex is named after Horace Lamb and Carl Wilhelm Oseen.
Mathematical description
Oseen looked for a solution for the Navier–Stokes equations in cylindrical coordinates with velocity components of the form
where is the circulation of the vortex core. Navier-Stokes equations lead to
which, subject to the conditions that it is regular at and becomes unity as , leads to
where is the kinematic viscosity of the fluid. At , we have a potential vortex with concentrated vorticity at the axis; and this vorticity diffuses away as time passes.
The only non-zero vorticity component is in the direction, given by
The pressure field simply ensures the vortex rotates in the circumferential direction, providing the centripetal force
where ρ is the constant density
Generalized Oseen vortex
The generalized Oseen vortex may obtained by looking for solutions of the form
that leads to the equation
Self-similar solution exists for the coordinate , provided , where is a constant, in which case . The solution for may be written according to Rott (1958) as
where is an arbitrary constant. For , the classical Lamb–Oseen vortex is recovered. The case corresponds to the axisymmetric stagnation point flow, where is a constant. When , , a Burgers vortex is a obtained. For arbitrary , the solution becomes , where is an arbitrary constant. As , Burgers vortex is recovered.
See also
T
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https://en.wikipedia.org/wiki/Batchelor%20vortex
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In fluid dynamics, Batchelor vortices, first described by George Batchelor in a 1964 article, have been found useful in analyses of airplane vortex wake hazard problems.
The model
The Batchelor vortex is an approximate solution to the Navier–Stokes equations obtained using a boundary layer approximation. The physical reasoning behind this approximation is the assumption that the axial gradient of the flow field of interest is of much smaller magnitude than the radial gradient.
The axial, radial and azimuthal velocity components of the vortex are denoted , and respectively and can be represented in cylindrical coordinates as follows:
The parameters in the above equations are
, the free-stream axial velocity,
, the velocity scale (used for nondimensionalization),
, the length scale (used for nondimensionalization),
, a measure of the core size, with initial core size and representing viscosity,
, the swirl strength, given as a ratio between the maximum tangential velocity and the core velocity.
Note that the radial component of the velocity is zero and that the axial and azimuthal components depend only on .
We now write the system above in dimensionless form by scaling time by a factor . Using the same symbols for the dimensionless variables, the Batchelor vortex can be expressed in terms of the dimensionless variables as
where denotes the free stream axial velocity and is the Reynolds number.
If one lets and considers an infinitely large swirl number then
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https://en.wikipedia.org/wiki/Jim%20Eno
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Jim Eno (born February 8, 1966) is the drummer and one of the founding members of the Austin, Texas band Spoon. He is also a record producer and a semiconductor chip designer.
Overview
Eno was born in Rhode Island. He studied electrical engineering at North Carolina State University and worked as a hardware design engineer at Compaq Computer Corporation in Houston before moving to Austin in 1992 to design microchips for Motorola. Since joining Spoon he has also worked for Metta Technology as an electrical engineer, but has worked entirely in music since mid-2006.
Eno met the lead singer of Spoon, Britt Daniel, when replacing the drummer of Daniel's former band The Alien Beats. He owns and operates a studio called Public Hi-Fi in Austin, Texas, where the band has often recorded. He has co-produced albums for Spoon and has produced albums for other bands, including !!!, Heartless Bastards, The Relatives and The Strange Boys (discography below). Eno is also an accomplished engineer, working alongside producers Tony Visconti and Steve Berlin. He recently produced two songs for the solo debut of former Voxtrot frontman, Ramesh Srivastava, and mixed all three of the "EP 1" songs.
Starting at the Austin City Limits Festival in 2012 and continuing with SXSW 2013, 2014 and 2015, Jim Eno has been curating exclusive sessions for Spotify. Artists featured include: The Shins, Palma Violets, Father John Misty, The 1975, Phantogram, Poliça, Jagwar Ma, The Hold Steady, Rag'n'Bone Ma
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https://en.wikipedia.org/wiki/Nikolay%20Umov
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Nikolay Alekseevich Umov (; January 23, 1846 – January 15, 1915) was a Russian physicist and mathematician known for discovering the concept of Umov-Poynting vector and Umov effect.
Biography
Umov was born in 1846 in Simbirsk (present-day Ulyanovsk) in the family of a military doctor. He graduated from the Physics and Mathematics department of Moscow State University in 1867 and became a Professor of Physics in 1875. He studied theoretical physics by reading works of Gabriel Lamé, Clebsch and Clausius, that made a significant impact on the originality of his later ideas in physics.
Umov became the head of the Physics department of Moscow State University (MSU) after Aleksandr Stoletov died in 1896. Together with Pyotr Lebedev, Umov actively participated in founding the Physical Institute at the MSU.
He organized several educational societies. He was the president of the Moscow Society of Nature Explorers for 17 years. He was among the first Russian scientists who acknowledged the importance of the theory of relativity. In 1911, along with a group of leading professors, he left Moscow University in protest of reactionary actions of the government. Umov died in 1915 in Moscow.
Contribution to physics
Umov was the first who introduced in physics such basic concepts as speed and direction of movement of energy, which are now associated with Umov-Poynting vector, and density of energy in a given point of space. During his work in Odessa from 1873 to 1874, Umov published first
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https://en.wikipedia.org/wiki/Symmetric%20product%20of%20an%20algebraic%20curve
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In mathematics, the n-fold symmetric product of an algebraic curve C is the quotient space of the n-fold cartesian product
C × C × ... × C
or Cn by the group action of the symmetric group Sn on n letters permuting the factors. It exists as a smooth algebraic variety denoted by ΣnC. If C is a compact Riemann surface, ΣnC is therefore a complex manifold. Its interest in relation to the classical geometry of curves is that its points correspond to effective divisors on C of degree n, that is, formal sums of points with non-negative integer coefficients.
For C the projective line (say the Riemann sphere ∪ {∞} ≈ S2), its nth symmetric product ΣnC can be identified with complex projective space of dimension n.
If G has genus g ≥ 1 then the ΣnC are closely related to the Jacobian variety J of C. More accurately for n taking values up to g they form a sequence of approximations to J from below: their images in J under addition on J (see theta-divisor) have dimension n and fill up J, with some identifications caused by special divisors.
For g = n we have ΣgC actually birationally equivalent to J; the Jacobian is a blowing down of the symmetric product. That means that at the level of function fields it is possible to construct J by taking linearly disjoint copies of the function field of C, and within their compositum taking the fixed subfield of the symmetric group. This is the source of André Weil's technique of constructing J as an abstract variety from 'birational data'.
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https://en.wikipedia.org/wiki/Linearly%20disjoint
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In mathematics, algebras A, B over a field k inside some field extension of k are said to be linearly disjoint over k if the following equivalent conditions are met:
(i) The map induced by is injective.
(ii) Any k-basis of A remains linearly independent over B.
(iii) If are k-bases for A, B, then the products are linearly independent over k.
Note that, since every subalgebra of is a domain, (i) implies is a domain (in particular reduced). Conversely if A and B are fields and either A or B is an algebraic extension of k and is a domain then it is a field and A and B are linearly disjoint. However, there are examples where is a domain but A and B are not linearly disjoint: for example, A = B = k(t), the field of rational functions over k.
One also has: A, B are linearly disjoint over k if and only if subfields of generated by , resp. are linearly disjoint over k. (cf. Tensor product of fields)
Suppose A, B are linearly disjoint over k. If , are subalgebras, then and are linearly disjoint over k. Conversely, if any finitely generated subalgebras of algebras A, B are linearly disjoint, then A, B are linearly disjoint (since the condition involves only finite sets of elements.)
See also
Tensor product of fields
References
P.M. Cohn (2003). Basic algebra
Algebra
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https://en.wikipedia.org/wiki/CoSy
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CoSy, short for Conferencing System, was an early computer conferencing system developed at the University of Guelph.
The CoS software grew out of an interest in group computer mediated communication systems in 1981 by Dick Mason and John Black. A project was initiated in the Institute of Computer Science to investigate and possibly acquire an asynchronous computer conferencing system, and a small team of Bob McQueen, Alastair Mayer and Peter Jaspers-Fayer undertook the investigation of two existing systems, EIES from New Jersey, and COM from Sweden. It was then decided that developing a new system in-house would be the best path to take.
A new system started to take shape, written in C and operating under a UNIX operating system on a Digital Equipment Corporation PDP-11 with dial-up telephone ports. Much thought was given to the user interface and group interaction processes, especially as most of the user dial-up connections were originally at very slow 300 bits (30 characters) per second through acoustic modems. The system was gradually introduced to and tested by a small group of users, and eventually made available to other external organizations beginning in 1983. Licenses to use the Unix version of the software were granted to other sites, mainly universities, and a VMS version was also developed and made available for license. CoSy was selected by Byte to launch their BIX system in 1985
In addition to BIX, it was used to implement a similar British system name
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https://en.wikipedia.org/wiki/Prime%20decomposition%20of%203-manifolds
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In mathematics, the prime decomposition theorem for 3-manifolds states that every compact, orientable 3-manifold is the connected sum of a unique (up to homeomorphism) finite collection of prime 3-manifolds.
A manifold is prime if it cannot be presented as a connected sum of more than one manifold, none of which is the sphere of the same dimension. This condition is necessary since for any manifold M of dimension it is true that
(where means the connected sum of and ). If is a prime 3-manifold then either it is or the non-orientable bundle over
or it is irreducible, which means that any embedded 2-sphere bounds a ball. So the theorem can be restated to say that there is a unique connected sum decomposition into irreducible 3-manifolds and fiber bundles of over
The prime decomposition holds also for non-orientable 3-manifolds, but the uniqueness statement must be modified slightly: every compact, non-orientable 3-manifold is a connected sum of irreducible 3-manifolds and non-orientable bundles over This sum is unique as long as we specify that each summand is either irreducible or a non-orientable bundle over
The proof is based on normal surface techniques originated by Hellmuth Kneser. Existence was proven by Kneser, but the exact formulation and proof of the uniqueness was done more than 30 years later by John Milnor.
References
3-manifolds
Manifolds
Theorems in differential geometry
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https://en.wikipedia.org/wiki/Normal%20surface
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In mathematics, a normal surface is a surface inside a triangulated 3-manifold that intersects each tetrahedron so that each component of intersection is a triangle or a quad (see figure). A triangle cuts off a vertex of the tetrahedron while a quad separates pairs of vertices. A normal surface may have many components of intersection, called normal disks, with one tetrahedron, but no two normal disks can be quads that separate different pairs of vertices since that would lead to the surface self-intersecting.
Dually, a normal surface can be considered to be a surface that intersects each handle of a given handle structure on the 3-manifold in a prescribed manner similar to the above.
The concept of normal surface can be generalized to arbitrary polyhedra. There are also related notions of almost normal surface and spun normal surface.
The concept of normal surface is due to Hellmuth Kneser, who utilized it in his proof of the prime decomposition theorem for 3-manifolds. Later Wolfgang Haken extended and refined the notion to create normal surface theory, which is at the basis of many of the algorithms in 3-manifold theory. The notion of almost normal surfaces is due to Hyam Rubinstein. The notion of spun normal surface is due to Bill Thurston.
Regina is software which enumerates normal and almost-normal surfaces in triangulated 3-manifolds, implementing Rubinstein's 3-sphere recognition algorithm, among other things.
References
Hatcher, Notes on basic 3-manifo
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https://en.wikipedia.org/wiki/Chemical%20nomenclature
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A chemical nomenclature is a set of rules to generate systematic names for chemical compounds. The nomenclature used most frequently worldwide is the one created and developed by the International Union of Pure and Applied Chemistry (IUPAC).
The IUPAC's rules for naming organic and inorganic compounds are contained in two publications, known as the Blue Book and the Red Book, respectively. A third publication, known as the Green Book, recommends the use of symbols for physical quantities (in association with the IUPAP), while a fourth, the Gold Book, defines many technical terms used in chemistry. Similar compendia exist for biochemistry (the White Book, in association with the IUBMB), analytical chemistry (the Orange Book), macromolecular chemistry (the Purple Book), and clinical chemistry (the Silver Book). These "color books" are supplemented by specific recommendations published periodically in the journal Pure and Applied Chemistry.
Aims of chemical nomenclature
The main goal of chemical nomenclature is to disambiguate the spoken or written names of chemical compounds: each name should refer to one compound. Secondarily: each compound should have only one name, although in some cases some alternative names are accepted.
Preferably, the name should also reflect the structure or chemistry of a compound. This is achieved by the International Chemical Identifier (InChI) nomenclature. However, the American Chemical Society's CAS numbers nomenclature reflects nothing of t
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https://en.wikipedia.org/wiki/Impress
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Impress or Impression may refer to:
Arts
Big Impression, a British comedy sketch show
Impression, Sunrise, a painting by Claude Monet
Biology
Maternal impression, an obsolete scientific theory that explained the existence of birth defects and congenital disorders
IMPReSS, a database of standardized phenotyping protocols used by the International Mouse Phenotyping Consortium
Computing
Impress, a presentation program included in StarOffice, there are four descendant office suites
Apache OpenOffice Impress
Collabora Online Impress
LibreOffice Impress
NeoOffice Impress
Legal
Case of first impression, a case or controversy over an interpretation of law never before reported or decided by that court.
Present sense impression, in the law of evidence, is a statement made by a person that conveys their sense of the state of certain things at the time the person was perceiving the event, or immediately thereafter.
Printing
Impression, a synonym for a print run in the publishing industry.
Impression seal, a type of accent seal.
Other uses
IMPRESS, Independent Monitor for the Press, a press regulator in the United Kingdom
Cost Per Impression, a term used in online marketing for measuring the worth and cost of a specific e-marketing campaign.
Impressment, the act of conscripting people to serve in the military or navy.
See also
First impression (disambiguation)
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https://en.wikipedia.org/wiki/Dirichlet%27s%20test
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In mathematics, Dirichlet's test is a method of testing for the convergence of a series. It is named after its author Peter Gustav Lejeune Dirichlet, and was published posthumously in the Journal de Mathématiques Pures et Appliquées in 1862.
Statement
The test states that if is a sequence of real numbers and a sequence of complex numbers satisfying
is monotonic
for every positive integer N
where M is some constant, then the series
converges.
Proof
Let and .
From summation by parts, we have that . Since is bounded by M and , the first of these terms approaches zero, as .
We have, for each k, .
Since is monotone, it is either decreasing or increasing:
<li>
If is decreasing,
which is a telescoping sum that equals and therefore approaches as . Thus, converges.
<li>
If is increasing,
which is again a telescoping sum that equals and therefore approaches as . Thus, again, converges.
So, the series converges, by the absolute convergence test. Hence converges.
Applications
A particular case of Dirichlet's test is the more commonly used alternating series test for the case
Another corollary is that converges whenever is a decreasing sequence that tends to zero. To see that
is bounded, we can use the summation formula
Improper integrals
An analogous statement for convergence of improper integrals is proven using integration by parts. If the integral of a function f is uniformly bounded over all intervals, and g is a non-negative monotonicall
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https://en.wikipedia.org/wiki/Glossary%20of%20arithmetic%20and%20diophantine%20geometry
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This is a glossary of arithmetic and diophantine geometry in mathematics, areas growing out of the traditional study of Diophantine equations to encompass large parts of number theory and algebraic geometry. Much of the theory is in the form of proposed conjectures, which can be related at various levels of generality.
Diophantine geometry in general is the study of algebraic varieties V over fields K that are finitely generated over their prime fields—including as of special interest number fields and finite fields—and over local fields. Of those, only the complex numbers are algebraically closed; over any other K the existence of points of V with coordinates in K is something to be proved and studied as an extra topic, even knowing the geometry of V.
Arithmetic geometry can be more generally defined as the study of schemes of finite type over the spectrum of the ring of integers. Arithmetic geometry has also been defined as the application of the techniques of algebraic geometry to problems in number theory.
A
B
C
D
E
F
G
H
I
K
L
M
N
O
Q
R
S
T
U
V
W
See also
Arithmetic topology
Arithmetic dynamics
References
Further reading
Dino Lorenzini (1996), An invitation to arithmetic geometry, AMS Bookstore,
Diophantine geometry
Algebraic geometry
Geometry
Wikipedia glossaries using description lists
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https://en.wikipedia.org/wiki/Positive%20definiteness
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In mathematics, positive definiteness is a property of any object to which a bilinear form or a sesquilinear form may be naturally associated, which is positive-definite. See, in particular:
Positive-definite bilinear form
Positive-definite function
Positive-definite function on a group
Positive-definite functional
Positive-definite kernel
Positive-definite matrix
Positive-definite quadratic form
References
.
.
Quadratic forms
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https://en.wikipedia.org/wiki/Jacobi%20sum
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In mathematics, a Jacobi sum is a type of character sum formed with Dirichlet characters. Simple examples would be Jacobi sums J(χ, ψ) for Dirichlet characters χ, ψ modulo a prime number p, defined by
where the summation runs over all residues (for which neither a nor is 0). Jacobi sums are the analogues for finite fields of the beta function. Such sums were introduced by C. G. J. Jacobi early in the nineteenth century in connection with the theory of cyclotomy. Jacobi sums J can be factored generically into products of powers of Gauss sums g. For example, when the character χψ is nontrivial,
analogous to the formula for the beta function in terms of gamma functions. Since the nontrivial Gauss sums g have absolute value p, it follows that also has absolute value p when the characters χψ, χ, ψ are nontrivial. Jacobi sums J lie in smaller cyclotomic fields than do the nontrivial Gauss sums g. The summands of for example involve no pth root of unity, but rather involve just values which lie in the cyclotomic field of th roots of unity. Like Gauss sums, Jacobi sums have known prime ideal factorisations in their cyclotomic fields; see Stickelberger's theorem.
When χ is the Legendre symbol,
In general the values of Jacobi sums occur in relation with the local zeta-functions of diagonal forms. The result on the Legendre symbol amounts to the formula for the number of points on a conic section that is a projective line over the field of p elements. A paper of André Weil f
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https://en.wikipedia.org/wiki/G%20band
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G band may refer to:
G band (IEEE), a millimetre wave band from 110 to 300 GHz
G band (NATO), a radio frequency band from 4 to 6 GHz
G band, representing a green hued wavelength of in the photometric systems adopted by astronomers
G banding, in cytogenetics
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https://en.wikipedia.org/wiki/Generalized%20suffix%20tree
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In computer science, a generalized suffix tree is a suffix tree for a set of strings. Given the set of strings of total length , it is a Patricia tree containing all suffixes of the strings. It is mostly used in bioinformatics.
Functionality
It can be built in time and space, and can be used to find all occurrences of a string of length in time, which is asymptotically optimal (assuming the size of the alphabet is constant).
When constructing such a tree, each string should be padded with a unique out-of-alphabet marker symbol (or string) to ensure no suffix is a substring of another, guaranteeing each suffix is represented by a unique leaf node.
Algorithms for constructing a GST include Ukkonen's algorithm (1995) and McCreight's algorithm (1976).
Example
A suffix tree for the strings ABAB and BABA is shown in a figure above. They are padded with the unique terminator strings $0 and $1. The numbers in the leaf nodes are string number and starting position. Notice how a left to right traversal of the leaf nodes corresponds to the sorted order of the suffixes. The terminators might be strings or unique single symbols. Edges on $ from the root are left out in this example.
Alternatives
An alternative to building a generalized suffix tree is to concatenate the strings, and build a regular suffix tree or suffix array for the resulting string. When hits are evaluated after a search, global positions are mapped into documents and local positions with some algorithm an
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https://en.wikipedia.org/wiki/GEO600
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GEO600 is a gravitational wave detector located near Sarstedt, a town 20 km to the south of Hanover, Germany. It is designed and operated by scientists from the Max Planck Institute for Gravitational Physics, Max Planck Institute of Quantum Optics and the Leibniz Universität Hannover, along with University of Glasgow, University of Birmingham and Cardiff University in the United Kingdom, and is funded by the Max Planck Society and the Science and Technology Facilities Council (STFC). GEO600 is capable of detecting gravitational waves in the frequency range 50 Hz to 1.5 kHz, and is part of a worldwide network of gravitational wave detectors. This instrument, and its sister interferometric detectors, when operational, are some of the most sensitive gravitational wave detectors ever designed. They are designed to detect relative changes in distance of the order of 10−21, about the size of a single atom compared to the distance from the Sun to the Earth. Construction on the project began in 1995.
In March 2020 the COVID-19 pandemic forced the suspension of operation of other gravitational wave observatories such as LIGO and Virgo (and in April 2020, KAGRA) but GEO600 continued operations.
As of 2023, GEO600 is active in its gravitational wave observation operations.
History
In the 1970s, two groups in Europe, one led by Heinz Billing in Germany and one led by Ronald Drever in UK, initiated investigations into laser-interferometric gravitational wave detection. In 1975 the Max
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https://en.wikipedia.org/wiki/Maurice%20Anthony%20Biot
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Maurice Anthony Biot (May 25, 1905 – September 12, 1985) was a Belgian-American applied physicist. He made contributions in thermodynamics, aeronautics, geophysics, earthquake engineering, and electromagnetism. Particularly, he was accredited as the founder of the theory of poroelasticity.
Born in Antwerp, Belgium, Biot studied at Catholic University of Leuven in Belgium where he received a bachelor's degrees in philosophy (1927), mining engineering (1929) and electrical engineering (1930), and Doctor of Science in 1931. He obtained his Ph.D. in Aeronautical Science from the California Institute of Technology in 1932 under Theodore von Kármán.
In 1930s and 1940s Biot worked at Harvard University, the Catholic University of Leuven, Columbia University and Brown University, and later for a number of companies and government agencies, including NASA during the Space Program in the 1960s. Since 1969, Biot became a private consultant for various companies and agencies, and particularly for Shell Research and Development.
Biot's early work with von Kármán and during the World War II working for the US Navy Bureau of Aeronautics led to the development of the three-dimensional theory of aircraft flutter. During the period between 1932 and 1942, he conceived and then fully developed the response spectrum method (RSM) for earthquake engineering. For irreversible thermodynamics, Biot utilized the variational approach and was the first to introduce the dissipation function and the min
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https://en.wikipedia.org/wiki/Poroelasticity
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Poroelasticity is a field in materials science and mechanics that studies the interaction between fluid flow and solids deformation within a linear porous medium and it is an extension of elasticity and porous medium flow (diffusion equation). The deformation of the medium influences the flow of the fluid and vice versa. The theory was proposed by Maurice Anthony Biot (1935, 1941) as a theoretical extension of soil consolidation models developed to calculate the settlement of structures placed on fluid-saturated porous soils.
The theory of poroelasticity has been widely applied in geomechanics, hydrology, biomechanics, tissue mechanics, cell mechanics, and micromechanics.
An intuitive sense of the response of a saturated elastic porous medium to mechanical loading can be developed by thinking about, or experimenting with, a fluid-saturated sponge. If a fluid- saturated sponge is compressed, fluid will flow from the sponge. If the sponge is in a fluid reservoir and compressive pressure is subsequently removed, the sponge will reimbibe the fluid and expand. The volume of the sponge will also increase if its exterior openings are sealed and the pore fluid pressure is increased. The basic ideas underlying the theory of poroelastic materials are that the pore fluid pressure contributes to the total stress in the porous matrix medium and that the pore fluid pressure alone can strain the porous matrix medium. There is fluid movement in a porous medium due to differences in pore flu
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https://en.wikipedia.org/wiki/Lady%20Margaret%20School
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Lady Margaret School is an all-girls' Church of England secondary school in Parsons Green, Fulham, London. It was awarded specialist school status (a government funding scheme defunct since 2010) as a Mathematics & Computing College in September 2003, and became an academy in September 2012. In September 2017 it celebrated its 100th anniversary. Princess Alexandra is patron of the centenary having previously opened the new assembly hall in 1965. Princess Alexandra attended a service to celebrate the centenary of Lady Margaret School at Westminster Abbey (the resting place of Lady Margaret Beaufort) on Tuesday 17 October 2017. The service was conducted by the Dean of Westminster, John Hall.
Now
The school has approximately 742 girls aged between 11 and 18 years, about 175 of whom are in the sixth form. The majority of girls stay on into the sixth form. A number of students from other schools are given places in the sixth form following its expansion with the opening of the purpose-built Olivier Centre in 2010.
The headteacher is Elisabeth Stevenson, following the retirement of Sally Whyte in July 2015.
Today, Lady Margaret School is a Church of England academy in the London Borough of Hammersmith and Fulham. In 2003, the school achieved specialist status in mathematics and computing. In 2007, the school was described by Ofsted as 'good with outstanding features' and by the Statutory Inspection of Anglican Schools as 'outstanding'.
In 2010, the school opened a new building
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https://en.wikipedia.org/wiki/Thin%20set%20%28Serre%29
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In mathematics, a thin set in the sense of Serre, named after Jean-Pierre Serre, is a certain kind of subset constructed in algebraic geometry over a given field K, by allowed operations that are in a definite sense 'unlikely'. The two fundamental ones are: solving a polynomial equation that may or may not be the case; solving within K a polynomial that does not always factorise. One is also allowed to take finite unions.
Formulation
More precisely, let V be an algebraic variety over K (assumptions here are: V is an irreducible set, a quasi-projective variety, and K has characteristic zero). A type I thin set is a subset of V(K) that is not Zariski-dense. That means it lies in an algebraic set that is a finite union of algebraic varieties of dimension lower than d, the dimension of V. A type II thin set is an image of an algebraic morphism (essentially a polynomial mapping) φ, applied to the K-points of some other d-dimensional algebraic variety V′, that maps essentially onto V as a ramified covering with degree e > 1. Saying this more technically, a thin set of type II is any subset of
φ(V′(K))
where V′ satisfies the same assumptions as V and φ is generically surjective from the geometer's point of view. At the level of function fields we therefore have
[K(V): K(V′)] = e > 1.
While a typical point v of V is φ(u) with u in V′, from v lying in K(V) we can conclude typically only that the coordinates of u come from solving a degree e equation over K. The whole object of
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https://en.wikipedia.org/wiki/Belyi%27s%20theorem
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In mathematics, Belyi's theorem on algebraic curves states that any non-singular algebraic curve C, defined by algebraic number coefficients, represents a compact Riemann surface which is a ramified covering of the Riemann sphere, ramified at three points only.
This is a result of G. V. Belyi from 1979. At the time it was considered surprising, and it spurred Grothendieck to develop his theory of dessins d'enfant, which describes non-singular algebraic curves over the algebraic numbers using combinatorial data.
Quotients of the upper half-plane
It follows that the Riemann surface in question can be taken to be the quotient
H/Γ
(where H is the upper half-plane and Γ is a subgroup of finite index in the modular group) compactified by cusps. Since the modular group has non-congruence subgroups, it is not the conclusion that any such curve is a modular curve.
Belyi functions
A Belyi function is a holomorphic map from a compact Riemann surface S to the complex projective line P1(C) ramified only over three points, which after a Möbius transformation may be taken to be . Belyi functions may be described combinatorially by dessins d'enfants.
Belyi functions and dessins d'enfants – but not Belyi's theorem – date at least to the work of Felix Klein; he used them in his article to study an 11-fold cover of the complex projective line with monodromy group PSL(2,11).
Applications
Belyi's theorem is an existence theorem for Belyi functions, and has subsequently been much used
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https://en.wikipedia.org/wiki/Spring%20%28mathematics%29
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In geometry, a spring is a surface in the shape of a coiled tube, generated by sweeping a circle about the path of a helix.
Definition
A spring wrapped around the z-axis can be defined parametrically by:
where
is the distance from the center of the tube to the center of the helix,
is the radius of the tube,
is the speed of the movement along the z axis (in a right-handed Cartesian coordinate system, positive values create right-handed springs, whereas negative values create left-handed springs),
is the number of rounds in a spring.
The implicit function in Cartesian coordinates for a spring wrapped around the z-axis, with = 1 is
The interior volume of the spiral is given by
Other definitions
Note that the previous definition uses a vertical circular cross section. This is not entirely accurate as the tube becomes increasingly distorted as the Torsion increases (ratio of the speed and the incline of the tube).
An alternative would be to have a circular cross section in the plane perpendicular to the helix curve. This would be closer to the shape of a physical spring. The mathematics would be much more complicated.
The torus can be viewed as a special case of the spring obtained when the helix degenerates to a circle.
References
See also
Spiral
Helix
Surfaces
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https://en.wikipedia.org/wiki/Yakov%20Frenkel
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Yakov Il'ich Frenkel (; 10 February 1894 – 23 January 1952) was a Soviet physicist renowned for his works in the field of condensed-matter physics. He is also known as Jacov Frenkel, frequently using the name J. Frenkel in publications in English.
Early years
He was born to a Jewish family in Rostov on Don, in the Don Host Oblast of the Russian Empire on 10 February 1894. His father was involved in revolutionary activities and spent some time in internal exile to Siberia; after the danger of pogroms started looming in 1905, the family spent some time in Switzerland, where Yakov Frenkel began his education. In 1912, while studying in the Karl May Gymnasium in St. Petersburg, he completed his first physics work on the Earth's magnetic field and atmospheric electricity. This work attracted Abram Ioffe's attention and later led to collaboration with him. He considered moving to the USA (which he visited in the summer of 1913, supported by money hard-earned by tutoring) but was nevertheless admitted to St. Petersburg University in the winter semester of 1913, at which point any emigration plans ended. Frenkel graduated from the university in three years and remained there to prepare for a professorship (his oral exam for the master's degree was delayed due to the events of the October revolution). His first scientific paper came to light in 1917.
Early scientific career
In the last years of the Great War and until 1921 Frenkel was involved (along with Igor Tamm) in the foundat
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https://en.wikipedia.org/wiki/Riemann%E2%80%93Roch%20theorem%20for%20surfaces
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In mathematics, the Riemann–Roch theorem for surfaces describes the dimension of linear systems on an algebraic surface. The classical form of it was first given by , after preliminary versions of it were found by and . The sheaf-theoretic version is due to Hirzebruch.
Statement
One form of the Riemann–Roch theorem states that if D is a divisor on a non-singular projective surface then
where χ is the holomorphic Euler characteristic, the dot . is the intersection number, and K is the canonical divisor. The constant χ(0) is the holomorphic Euler characteristic of the trivial bundle, and is equal to 1 + pa, where pa is the arithmetic genus of the surface. For comparison, the Riemann–Roch theorem for a curve states that χ(D) = χ(0) + deg(D).
Noether's formula
Noether's formula states that
where χ=χ(0) is the holomorphic Euler characteristic, c12 = (K.K) is a Chern number and the self-intersection number of the canonical class K, and e = c2 is the topological Euler characteristic. It can be used to replace the
term χ(0) in the Riemann–Roch theorem with topological terms; this gives the Hirzebruch–Riemann–Roch theorem for surfaces.
Relation to the Hirzebruch–Riemann–Roch theorem
For surfaces, the Hirzebruch–Riemann–Roch theorem is essentially the Riemann–Roch theorem for surfaces combined with the Noether formula. To see this, recall that for each divisor D on a surface there is an invertible sheaf L = O(D) such that the linear system of D is more or less the space of sect
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https://en.wikipedia.org/wiki/Cletus%20Wotorson
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Cletus Segbe Wotorson (born 13 March 1937) is a Liberian politician and geologist. On March 26, 2009 he was elected as President Pro Tempore of the Senate of Liberia, beating out fellow Senator Gbehzohngar Milton Findley. He served until 2012.
Positions
Assistant Professor of Geology & Geophysics – University of Liberia
Director – Liberian Geological Survey (1973–1975)
Founder & President – West Africa Consultants (1975–1978)
Minister of Lands & Mines – Government of Liberia (1978–1980)
Chairman – Liberian Petroleum Refinery Company (1978–1980)
Chairman & CEO – Liberian Petroleum Refinery Company (1980–1983)
President – Nimba Mining Company (1988–1990)
Standard Bearer of the Alliance of Political Parties in the 1997 presidential election. He placed fourth out of thirteen candidates, winning 2.57% of the vote
References
1937 births
Living people
Academic staff of the University of Liberia
Members of the Senate of Liberia
Presidents pro tempore of the Senate of Liberia
Candidates for President of Liberia
Government ministers of Liberia
Unity Party (Liberia) politicians
People from Grand Kru County
20th-century Liberian politicians
21st-century Liberian politicians
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https://en.wikipedia.org/wiki/Madelung
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Madelung is a German surname. It is also the name of multiple terms in mathematics and science based on people named Madelung.
People
Erwin Madelung (1881–1972), German physicist
Georg Hans Madelung (1889–1972), German aeronautical engineer
Otto Wilhelm Madelung (1846–1926), German surgeon
Wilferd Madelung (1930–2023), German-American author and scholar of Islamic history
Mathematics and science
Madelung constant, chemical energy of an ion in a crystal, named after Erwin Madelung
Madelung equations, Erwin Madelung's equivalent alternative formulation of the Schrödinger equation
Medicine
Madelung's deformity, characterized by malformed wrists and wrist bones, and short stature, named after Otto Wilhelm Madelung
Madelung's syndrome, also known as "benign symmetric lipomatosis", named after Otto Wilhelm Madelung
German-language surnames
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https://en.wikipedia.org/wiki/Bland%E2%80%93Altman%20plot
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A Bland–Altman plot (difference plot) in analytical chemistry or biomedicine is a method of data plotting used in analyzing the agreement between two different assays. It is identical to a Tukey mean-difference plot, the name by which it is known in other fields, but was popularised in medical statistics by J. Martin Bland and Douglas G. Altman.
Agreement versus correlation
Bland and Altman drive the point that any two methods that are designed to measure the same parameter (or property) should have good correlation when a set of samples are chosen such that the property to be determined varies considerably. A high correlation for any two methods designed to measure the same property could thus in itself just be a sign that one has chosen a widespread sample. A high correlation does not necessarily imply that there is good agreement between the two methods.
Construction
Consider a sample consisting of observations (for example, objects of unknown volume). Both assays (for example, different methods of volume measurement) are performed on each sample, resulting in data points. Each of the samples is then represented on the graph by assigning the mean of the two measurements as the -value, and the difference between the two values as the -value.
The Cartesian coordinates of a given sample with values of and determined by the two assays is
For comparing the dissimilarities between the two sets of samples independently from their mean values, it is more appropriate
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https://en.wikipedia.org/wiki/1%2C1%2C1%2C2%2C3%2C3%2C3-Heptafluoropropane
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1,1,1,2,3,3,3-Heptafluoropropane, also called heptafluoropropane, HFC-227ea (ISO name), HFC-227 or FM-200, as well as apaflurane (INN), is a colourless, odourless gaseous halocarbon commonly used as a gaseous fire suppression agent.
Chemistry
Its chemical formula is CF-CHF-CF, or CHF. With a boiling point of −16.4 °C, it is a gas at room temperature. It is slightly soluble in water (260 mg/L).
Use
HFC-227ea is used in fire suppression systems that protect data processing and telecommunication facilities, and in fire suppression of many flammable liquids and gases. HFC-227ea is categorized as a Clean Agent and is governed by NFPA 2001 - Standard for Clean Agent Fire Extinguishing Systems. Effective fire suppression requires introducing a concentration of the HFC-227ea agent between 6.25% and 9% depending on the hazard being suppressed. Its NOAEL for cardiac sensitization is 9%. The United States Environmental Protection Agency allows concentration of 9% volume in occupied spaces without mandated egress time, or up to 10.5% for a limited time. Most fire suppression systems are designed to provide concentration of 6.25-9%.
The HFC-227ea fire suppression agent was the first non-ozone-depleting replacement for Halon 1301. In addition, HFC-227ea leaves no residue on valuable equipment after discharge.
HFC-227ea contains no chlorine or bromine atoms, presenting no ozone depletion effect. Its atmospheric lifetime is approximated between 31 and 42 years. It leaves no residue o
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https://en.wikipedia.org/wiki/Schur%20polynomial
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In mathematics, Schur polynomials, named after Issai Schur, are certain symmetric polynomials in n variables, indexed by partitions, that generalize the elementary symmetric polynomials and the complete homogeneous symmetric polynomials. In representation theory they are the characters of polynomial irreducible representations of the general linear groups. The Schur polynomials form a linear basis for the space of all symmetric polynomials. Any product of Schur polynomials can be written as a linear combination of Schur polynomials with non-negative integral coefficients; the values of these coefficients is given combinatorially by the Littlewood–Richardson rule. More generally, skew Schur polynomials are associated with pairs of partitions and have similar properties to Schur polynomials.
Definition (Jacobi's bialternant formula)
Schur polynomials are indexed by integer partitions. Given a partition ,
where , and each is a non-negative integer, the functions
are alternating polynomials by properties of the determinant. A polynomial is alternating if it changes sign under any transposition of the variables.
Since they are alternating, they are all divisible by the Vandermonde determinant
The Schur polynomials are defined as the ratio
This is known as the bialternant formula of Jacobi. It is a special case of the Weyl character formula.
This is a symmetric function because the numerator and denominator are both alternating, and a polynomial since all alternating po
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https://en.wikipedia.org/wiki/Quinoxaline
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A quinoxaline, also called a benzopyrazine, in organic chemistry, is a heterocyclic compound containing a ring complex made up of a benzene ring and a pyrazine ring. It is isomeric with other naphthyridines including quinazoline, phthalazine and cinnoline. It is a colorless oil that melts just above room temperature. Although quinoxaline itself is mainly of academic interest, quinoxaline derivatives are used as dyes, pharmaceuticals (such as varenicline), and antibiotics such as olaquindox, carbadox, echinomycin, levomycin and actinoleutin.
Synthesis
They can be formed by condensing ortho-diamines with 1,2-diketones. The parent substance of the group, quinoxaline, results when glyoxal is condensed with 1,2-diaminobenzene. Substituted derivatives arise when α-ketonic acids, α-chlorketones, α-aldehyde alcohols and α-ketone alcohols are used in place of diketones. Quinoxaline and its analogues may also be formed by reduction of amino acids substituted 1,5-difluoro-2,4-dinitrobenzene (DFDNB):
One study used 2-iodoxybenzoic acid (IBX) as a catalyst in the reaction of benzil with 1,2-diaminobenzene:
Uses
The antitumoral properties of quinoxaline compounds have been of interest. Recently, quinoxaline and its analogs have been investigated as the catalyst's ligands.
References
Simple aromatic rings
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https://en.wikipedia.org/wiki/Cadmium%20fluoride
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Cadmium fluoride (CdF2) is a mostly water-insoluble source of cadmium used in oxygen-sensitive applications, such as the production of metallic alloys. In extremely low concentrations (ppm), this and other fluoride compounds are used in limited medical treatment protocols. Fluoride compounds also have significant uses in synthetic organic chemistry. The standard enthalpy has been found to be -167.39 kcal. mole−1 and the Gibbs energy of formation has been found to be -155.4 kcal. mole−1, and the heat of sublimation was determined to be 76 kcal. mole−1.
Preparation
Cadmium fluoride is prepared by the reaction of gaseous fluorine or hydrogen fluoride with cadmium metal or its salts, such as the chloride, oxide, or sulfate.
It may also be obtained by dissolving cadmium carbonate in 40% hydrofluoric acid solution, evaporating the solution and drying in a vacuum at 150 °C.
Another method of preparing it is to mix cadmium chloride and ammonium fluoride solutions, followed by crystallization. The insoluble cadmium fluoride is filtered from solution.
Cadmium fluoride has also been prepared by reacting fluorine with cadmium sulfide. This reaction happens very quickly and forms nearly pure fluoride at much lower temperatures than other reactions used.
Uses
Electronic conductor
CdF2 can be transformed into an electronic conductor when doped with certain rare earth elements or yttrium and treated with cadmium vapor under high temperature conditions. This process creates blue cryst
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https://en.wikipedia.org/wiki/Semimodule
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In mathematics, a semimodule over a semiring R is like a module over a ring except that it is only a commutative monoid rather than an abelian group.
Definition
Formally, a left R-semimodule consists of an additively-written commutative monoid M and a map from to M satisfying the following axioms:
.
A right R-semimodule can be defined similarly. For modules over a ring, the last axiom follows from the others. This is not the case with semimodules.
Examples
If R is a ring, then any R-module is an R-semimodule. Conversely, it follows from the second, fourth, and last axioms that (-1)m is an additive inverse of m for all , so any semimodule over a ring is in fact a module.
Any semiring is a left and right semimodule over itself in the same way that a ring is a left and right module over itself. Every commutative monoid is uniquely an -semimodule in the same way that an abelian group is a -module.
References
Algebraic structures
Module theory
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https://en.wikipedia.org/wiki/Air%20Command%20and%20Control%20System
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Air Command and Control System (ACCS) is the NATO project planned to replace the NATO Air Command and Control Systems of the 1990s. At the highest level it comprised the Combined Air Operations Centre (CAOC) from which the air battle is run. Beneath this level of command is the Air Control Centre (ACC), Recognized Air Picture (RAP) Production Centre (RPC) and Sensor Fusion Post (SFP) combined in one entity called ARS. The ARS is the equivalent to the Control and Reporting Centers (CRCs) operated in the 1990s. The ACCS project comprised both static and deployable elements. Under separate funding, NATO intended to procure deployable sensors for the deployable ACCS component (DAC).
Oversight of the project is provided by the NATO Communications and Information Agency (NCIA) in Brussels, Belgium. Until 2012, this was executed by the NATO ACCS Management Organisation (NACMA) Board of Directors, senior representatives of the Nations engaged in the NATO ACCS project. The Board is responsible to the Secretary General of NATO for the delivery of the project.
The NCIA AIRC2 PO&S is responsible for the day-to-day management of the project scientific support from former NC3A (now part of the NCIA), system and software engineering support from Systems Support Center (SSC) (as well part of the NCIA), logistic support from the NATO Support and Procurement Agency (NSPA - former NAMSA) and operational support from SHAPE.
History
The contract to build the ACCS was based on 1990s specif
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https://en.wikipedia.org/wiki/Mark%20Perakh
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Mark Perakh (; perach (פֶּ֫רַח) is the Hebrew word for "flower"; born Mark Yakovlevich Popereka in 1924, Kiev, Ukraine, died 7 May 2013 in Escondido, California), was a professor emeritus of Mathematics and statistical mechanics at California State University, Fullerton in Fullerton, California.
Perakh taught physics, researched superconductivity, and wrote some 300 scientific papers, but his fame particularly comes from his writing about science and religion on Talk Reason, a website he helped found, and from his regular contributions to the blog The Panda's Thumb.
On August 28, 1958 Perakh (then Popereka), who at the time had been the head of a department in Kazakh Agricultural University in Almaty (then Alma-Ata) and K.S.Frusin (department assistant) were sentenced for "badmouthing" the Soviet government and for spreading leaflets calling to vote against candidates in the then forthcoming elections to the Supreme Soviet of the USSR. Some of Perakh's short stories were inspired by his stay in the gulag.
In 2003, Perakh published Unintelligent Design (Prometheus Books, ), a book that is critical of Intelligent Design, and he is particularly skeptical of some of the arguments proposed by William Dembski, which he states are pseudomathematical. He also wrote critically of Old Earth creationist astronomer Hugh Ross, and has responded to claims by Jonathan Wells that the lack of published research by creationists contradicting the prevailing scientific consensus is due to a c
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https://en.wikipedia.org/wiki/Intersection%20theory
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In mathematics, intersection theory is one of the main branches of algebraic geometry, where it gives information about the intersection of two subvarieties of a given variety. The theory for varieties is older, with roots in Bézout's theorem on curves and elimination theory. On the other hand, the topological theory more quickly reached a definitive form.
There is yet an ongoing development of intersection theory. Currently the main focus is on: virtual fundamental cycles, quantum intersection rings, Gromov-Witten theory and the extension of intersection theory from schemes to stacks.
Topological intersection form
For a connected oriented manifold of dimension the intersection form is defined on the -th cohomology group (what is usually called the 'middle dimension') by the evaluation of the cup product on the fundamental class in . Stated precisely, there is a bilinear form
given by
with
This is a symmetric form for even (so doubly even), in which case the signature of is defined to be the signature of the form, and an alternating form for odd (so is singly even). These can be referred to uniformly as ε-symmetric forms, where respectively for symmetric and skew-symmetric forms. It is possible in some circumstances to refine this form to an -quadratic form, though this requires additional data such as a framing of the tangent bundle. It is possible to drop the orientability condition and work with coefficients instead.
These forms are important topological i
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https://en.wikipedia.org/wiki/IUPAC%20nomenclature%20of%20inorganic%20chemistry
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In chemical nomenclature, the IUPAC nomenclature of inorganic chemistry is a systematic method of naming inorganic chemical compounds, as recommended by the International Union of Pure and Applied Chemistry (IUPAC). It is published in Nomenclature of Inorganic Chemistry (which is informally called the Red Book). Ideally, every inorganic compound should have a name from which an unambiguous formula can be determined. There is also an IUPAC nomenclature of organic chemistry.
System
The names "caffeine" and "3,7-dihydro-1,3,7-trimethyl-1H-purine-2,6-dione" both signify the same chemical compound. The systematic name encodes the structure and composition of the caffeine molecule in some detail, and provides an unambiguous reference to this compound, whereas the name "caffeine" just names it. These advantages make the systematic name far superior to the common name when absolute clarity and precision are required. However, for the sake of brevity, even professional chemists will use the non-systematic name almost all of the time, because caffeine is a well-known common chemical with a unique structure. Similarly, H2O is most often simply called water in English, though other chemical names do exist.
Single atom anions are named with an -ide suffix: for example, H− is hydride.
Compounds with a positive ion (cation): The name of the compound is simply the cation's name (usually the same as the element's), followed by the anion. For example, NaCl is sodium chloride, and CaF2 is
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https://en.wikipedia.org/wiki/Hecke%20L-function
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In mathematics, a Hecke L-function may refer to:
an L-function of a modular form
an L-function of a Hecke character
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https://en.wikipedia.org/wiki/RecLOH
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RecLOH is a term in genetics that is an abbreviation for "Recombinant Loss of Heterozygosity".
This is a type of mutation which occurs with DNA by recombination. From a pair of equivalent ("homologous"), but slightly different (heterozygous) genes, a pair of identical genes results. In this case there is a non-reciprocal exchange of genetic code between the chromosomes, in contrast to chromosomal crossover, because genetic information is lost.
For Y chromosome
In genetic genealogy, the term is used particularly concerning similar seeming events in Y chromosome DNA. This type of mutation happens within one chromosome, and does not involve a reciprocal transfer. Rather, one homologous segment "writes over" the other. The mechanism is presumed to be different from RecLOH events in autosomal chromosomes, since the target is the very same chromosome instead of the homologous one.
During the mutation one of these copies overwrites the other. Thus the differences between the two are lost. Because differences are lost, heterozygosity is lost.
Recombination on the Y-chromosome does not only take place during meiosis, but virtually at every mitosis when the Y chromosome condenses, because it doesn't require pairing between chromosomes. Recombination frequency even exceeds the frame shift mutation frequency (slipped strand mispairing) of (average fast) Y-STRs, however many recombination products may lead to infertile germ cells and "daughter out".
Recombination events (RecLOH) can
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https://en.wikipedia.org/wiki/Opus%20Majus
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The (Latin for "Greater Work") is the most important work of Roger Bacon. It was written in Medieval Latin, at the request of Pope Clement IV, to explain the work that Bacon had undertaken. The 878-page treatise ranges over all aspects of natural science, from grammar and logic to mathematics, physics, and philosophy. Bacon sent his work to the Pope in 1267. It was followed later the same year by a smaller second work, his Opus Minus, which was intended as an abstract or summary of the longer work, followed shortly by a third work, Opus Tertium, as a preliminary introduction to the other two.
Contents
The is divided into seven parts:
Part one considers the obstacles to real wisdom and truth, classifying the causes of error (offendicula) into four categories: following a weak or unreliable authority, custom, the ignorance of others, and concealing one's own ignorance by pretended knowledge.
Part two considers the relationship between philosophy and theology, concluding that theology (and particularly Holy Scripture) is the foundation of all sciences.
Part three contains a study of Biblical languages: Latin, Greek, Hebrew, and Arabic, as a knowledge of language and grammar is necessary to understand revealed wisdom.
Part four contains a study of Mathematics: As part of the study, he vividly drew out the flaws in the Julian Calendar, proposing to drop a day every 125 years from 325 CE (Council of Nicaea). He also noted the shifting of the Equinoxes to the Solstices.
Part fi
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https://en.wikipedia.org/wiki/P%20series
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P series or P-series may refer to:
the p-series in mathematics, related to convergence of certain series
P-series fuels, blends of fuels
Huawei P series, mobile phone series by Huawei
IBM pSeries, computer series by IBM
Ruger P series – pistols
ThinkPad P series, mobile workstation line by Lenovo
Sony Cybershot P-series digital cameras, see Cyber-shot
Sony Vaio P series – notebook computers
Sony Ericsson P series, a series of cell phones
Vespa P-series motor scooters
See also
O series (disambiguation)
Q series (disambiguation)
T series (disambiguation)
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https://en.wikipedia.org/wiki/Small%20set%20%28category%20theory%29
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In category theory, a small set is one in a fixed universe of sets (as the word universe is used in mathematics in general). Thus, the category of small sets is the category of all sets one cares to consider. This is used when one does not wish to bother with set-theoretic concerns of what is and what is not considered a set, which concerns would arise if one tried to speak of the category of "all sets".
A small set is not to be confused with a small category, which is a category in which the collection of arrows (and therefore also the collection of objects) is a set.
In other choices of foundations, such as Grothendieck universes, there exist both sets that belong to the universe, called “small sets” and sets that do not, such as the universe itself, “large sets”. We gain an intermediate notion of moderate set: a subset of the universe, which may be small or large. Every small set is moderate, but not conversely.
Since in many cases the choice of foundations is irrelevant, it makes sense to always say “small set” for emphasis even if one has in mind a foundation where all sets are small.
Similarly, a small family is a family indexed by a small set; the axiom of replacement (if it applies in the foundation in question) then says that the image of the family is also small.
See also
Category of sets
References
S. Mac Lane, Ieke Moerdijk, Sheaves in geometry and logic: a first introduction to topos theory, , , the chapter on "Categorical preliminaries"
Categories in
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https://en.wikipedia.org/wiki/Large%20set%20%28combinatorics%29
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In combinatorial mathematics, a large set of positive integers
is one such that the infinite sum of the reciprocals
diverges. A small set is any subset of the positive integers that is not large; that is, one whose sum of reciprocals converges.
Large sets appear in the Müntz–Szász theorem and in the Erdős conjecture on arithmetic progressions.
Examples
Every finite subset of the positive integers is small.
The set of all positive integers is a large set; this statement is equivalent to the divergence of the harmonic series. More generally, any arithmetic progression (i.e., a set of all integers of the form an + b with a ≥ 1, b ≥ 1 and n = 0, 1, 2, 3, ...) is a large set.
The set of square numbers is small (see Basel problem). So is the set of cube numbers, the set of 4th powers, and so on. More generally, the set of positive integer values of any polynomial of degree 2 or larger forms a small set.
The set {1, 2, 4, 8, ...} of powers of 2 is a small set, and so is any geometric progression (i.e., a set of numbers of the form of the form abn with a ≥ 1, b ≥ 2 and n = 0, 1, 2, 3, ...).
The set of prime numbers is large. The set of twin primes is small (see Brun's constant).
The set of prime powers which are not prime (i.e., all numbers of the form pn with n ≥ 2 and p prime) is small although the primes are large. This property is frequently used in analytic number theory. More generally, the set of perfect powers is small; even the set of powerful numbers is small.
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https://en.wikipedia.org/wiki/Clock%20%28cryptography%29
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In cryptography, the clock was a method devised by Polish mathematician-cryptologist Jerzy Różycki, at the Polish General Staff's Cipher Bureau, to facilitate decrypting German Enigma ciphers. The method determined the rightmost rotor in the German Enigma by exploiting the different turnover positions. For the Poles, learning the rightmost rotor reduced the rotor-order search space by a factor of 3 (the number of rotors). The British improved the method, and it allowed them to use their limited number of bombes more effectively (the British confronted 5 to 8 rotors).
Method
This method sometimes made it possible to determine which of the Enigma machine's rotors was at the far right, that is, in the position where the rotor always revolved at every depression of a key. The clock method was developed by Jerzy Różycki during 1933–1935.
Marian Rejewski's grill method could determine the right-hand rotor, but that involved trying each possible rotor permutation (there were three rotors at the time) at each of its 26 possible starting rotations. The grill method tests were also complicated by the plugboard settings. In contrast, the clock method involved simple tests that were unaffected by the plugboard.
In the early 1930s, determining the rotor order was not a significant burden because the Germans used the same rotor order for three months at a time. The rotor order could be determined once, and then that order could be used for the next three months. On 1 February 1936, the
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https://en.wikipedia.org/wiki/Card%20catalog%20%28cryptology%29
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The card catalog, or "catalog of characteristics," in cryptography, was a system designed by Polish Cipher Bureau mathematician-cryptologist Marian Rejewski, and first completed about 1935 or 1936, to facilitate decrypting German Enigma ciphers.
History
The Polish Cipher Bureau used the theory of permutations to start breaking the Enigma cipher in late 1932. The Bureau recognized that the Enigma machine's doubled-key (see Grill (cryptology)) permutations formed cycles, and those cycles could be used to break the cipher. With German cipher keys provided by a French spy, the Bureau was able to reverse engineer the Enigma and start reading German messages. At the time, the Germans were using only 6 steckers, and the Polish grill method was feasible. On 1 August 1936, the Germans started using 8 steckers, and that change made the grill method less feasible. The Bureau needed an improved method to break the German cipher.
Although the steckers would change which letters were in a doubled-key's cycle, the steckers would not change the number of cycles or the length of those cycles. Steckers could be ignored. Ignoring the mid-key turnovers, the Enigma machine had only distinct settings of the three rotors, and the three rotors could only be arranged in the machine ways. That meant there were only likely doubled-key permutations. The Bureau set about determining and cataloging the characteristic of each of those likely permutations. Each letter of the key could be one of partiti
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https://en.wikipedia.org/wiki/Mostafa%20El-Sayed
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Mostafa A. El-Sayed (Arabic: مصطفى السيد) is an Egyptian-American physical chemist, a leading nanoscience researcher, a member of the National Academy of Sciences and a US National Medal of Science laureate. He was the editor-in-chief of the Journal of Physical Chemistry during a critical period of growth. He is also known for the spectroscopy rule named after him, the El-Sayed rule.
Early life and academic career
El-Sayed was born in Zifta, Egypt and spent his early life in Cairo. He earned his B.Sc. in chemistry from Ain Shams University Faculty of Science, Cairo in 1953. El-Sayed earned his doctoral degree in chemistry from Florida State University working with Michael Kasha, the last student of the legendary G. N. Lewis. While attending graduate school he met and married Janice Jones, his wife of 48 years. He spent time as a post-doctoral researcher at Harvard University, Yale University and the California Institute of Technology before joining the faculty of the University of California at Los Angeles in 1961. He spent over thirty years of his career at UCLA, while he and his wife raised five children (Lyla, Tarric, James, Dorea and Ivan). In 1994, he retired from UCLA and accepted the position of Julius Brown Chair and Regents Professor of Chemistry and Biochemistry at the Georgia Institute of Technology. He led the Laser Dynamics Lab there until his full retirement in 2020.
El-Sayed is a former editor-in-chief of the Journal of Physical Chemistry (1980–2004).
Res
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https://en.wikipedia.org/wiki/Godfrey%20v%20Demon%20Internet%20Service
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Godfrey v Demon Internet Service [2001] QB 201 was a landmark court case in the United Kingdom concerning online defamation and the liability of Internet service providers.
Facts
Laurence Godfrey—a physics lecturer—learned that someone had posted a message to the Usenet discussion group soc.culture.thai. That message—sent by an unknown source—had been forged to appear to have been sent by Dr. Godfrey.
On 17 January 1997 Godfrey contacted Demon Internet, to inform them of the forged message and ask that it be deleted from Demon Internet's Usenet news server. Demon Internet declined to remove the message, which remained on its servers for ten additional days, at which time it was automatically deleted along with all other old messages.
Godfrey sued for libel, citing Demon's failure to remove the forged message at the time of his initial complaint.
Judgment
Ruling on a pre-trial motion, the court found that an Internet service provider can be sued for libel, and that any transmission by a service provider of a defamatory posting constituted a publication under defamation law. Demon thereafter entered into an out-of-court settlement that paid Godfrey £15,000 plus £250,000 for his legal expenses.
There have since appeared several misrepresentations of the second of the two interlocutory judgments of Mr. Justice Morland in the (first) Godfrey v. Demon action. Having struck out the core of Demon's defence in his first judgment, Morland J considered a further application by the
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https://en.wikipedia.org/wiki/Netarhat%20Residential%20School
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Netarhat Residential School is a school in Netarhat, India. The school has a record of producing toppers of the Bihar School Examination Board year after year. The students have dominated the Regional Mathematics Olympiad and National Talent Search Examination (NTSE) conducted by the National Council of Educational Research and Training (NCERT). Students participate in inter-house and inter-set competitions and inter-school competitions. Santosh Kumar Singh is the present principal of Netarhat Residential School.
History
Netarhat Residential School was established on 15 November 1954, after the independence of India for the people of state of Bihar. It was a dream of the first chief minister of Bihar, Shri Krishna Singh and his deputy chief minister and finance minister Anugrah Narayan Sinha to establish a centre of excellence. The educationist Frederick Gordon Pearce, Jagadish Chandra Mather and Sachidanand Sinha played a vital role in making the plans for the school (or Netarhat Vidyalaya). Pearce has received kudos from Rajendra Prasad, then the president of India for his works.
Alumni
The alumni association is known as NOBA – Netarhat Old boys Association. There are chapters of NOBA, and the members meet regularly. On 12–13 November 2016, the Ranchi Chapter of NOBA organised the Global NOBA Meet at Mayuri Auditorium, CMPDI Kanke Road, Ranchi to discuss possibilities of giving back to the school and society.
Ambience
The school is situated far away from the busy life of
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https://en.wikipedia.org/wiki/Isaac%20Orobio%20de%20Castro
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Balthazar (Isaac) Orobio de Castro (c.1617 in Bragança, Portugal – November 7, 1687 in Amsterdam), was a Portuguese Jewish philosopher, physician and religious apologist.
Life
While still a child, he was taken to Seville by his parents, who were Marranos. He studied philosophy at Alcalá de Henares and became teacher of metaphysics at the University of Salamanca. Later he devoted himself to the study of medicine, and became a popular practitioner in Seville, and physician in ordinary to the duke of Medina-Celi and to a family nearly related to the king.
When married and father of a family, De Castro was, at the instigation of a servant whom he had punished for theft, denounced to the Inquisition as an adherent of Judaism, and thrown into a dark and narrow dungeon, where he remained for three years, subjected to the most frightful tortures. As he persistently denied the charge, he was finally released, but compelled to leave Spain and to wear the sanbenito, or penitential garment, for two years. He thereupon went to Toulouse, where he became professor of medicine at the university, at the same time receiving from Louis XIV the title of councilor; but, weary at last of hypocrisy and dissimulation, he went to Amsterdam about 1666, and there made a public confession of Judaism, adopting the name "Isaac." In that city De Castro continued the practice of medicine, and soon became a celebrity, being elected to membership in the directory of the Portuguese congregation and of severa
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https://en.wikipedia.org/wiki/Production%20system%20%28computer%20science%29
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A "production system" (or "production rule system") is a computer program typically used to provide some form of artificial intelligence, which consists primarily of a set of rules about behavior, but it also includes the mechanism necessary to follow those rules as the system responds to states of the world. Those rules, termed productions, are a basic representation found useful in automated planning, expert systems and action selection.
Productions consist of two parts: a sensory precondition (or "IF" statement) and an action (or "THEN"). If a production's precondition matches the current state of the world, then the production is said to be triggered. If a production's action is executed, it is said to have fired. A production system also contains a database, sometimes called working memory, which maintains data about the current state or knowledge, and a rule interpreter. The rule interpreter must provide a mechanism for prioritizing productions when more than one is triggered.
Basic operation
Rule interpreters generally execute a forward chaining algorithm for selecting productions to execute to meet current goals, which can include updating the system's data or beliefs. The condition portion of each rule (left-hand side or LHS) is tested against the current state of the working memory.
In idealized or data-oriented production systems, there is an assumption that any triggered conditions should be executed: the consequent actions (right-hand side or RHS) will up
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https://en.wikipedia.org/wiki/John%20Adelbert%20Parkhurst
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John Adelbert Parkhurst (September 24, 1861 – March 1, 1925) was an American astronomer.
He was born in Dixon, Illinois, and attended the public schools in Marengo, IL and Wheaton College. He then attended Rose Polytechnic Institute in Terre Haute, Indiana, earning a B.Sc. in 1886. For the following two years he taught mathematics at the same school. He was the son of Sanford Britton Parkhurst and Jane Clarissa Hubbard. Source: George Parkhurst Increasings by Peter G. Parkhurst, p. 402. In 1888 he married Anna Greenleaf.
He returned to Marengo, Illinois where he kept a small, private observatory that he used primarily for variable star observation. Yerkes Observatory was built nearby in 1897, and in 1898 he joined the staff as a volunteer research assistant. By 1900 he was appointed as an assistant. He remained on the staff for 25 years, later becoming an associate professor at the University of Chicago, specializing in practical astronomy.
His most important work was in the specialty of photometry. He also participated in three eclipse expeditions, but only enjoyed clear seeing conditions on the last (1925). During his career he published about 100 papers on astronomy, both before and during his time at Yerkes. In 1905 he was elected a fellow of the Royal Astronomical Society. On February 27, 1925, he suffered a cerebral hemorrhage and died a few days later at his home in Williams Bay. He was survived by his wife, Anna.
The crater Parkhurst on the Moon is named after him
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https://en.wikipedia.org/wiki/Ostrowski%20Prize
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The Ostrowski Prize is a mathematics award given every odd year for outstanding mathematical achievement judged by an international jury from the universities of Basel, Jerusalem, Waterloo and the academies of Denmark and the Netherlands. Alexander Ostrowski, a longtime professor at the University of Basel, left his estate to the foundation in order to establish a prize for outstanding achievements in pure mathematics and the foundations of numerical mathematics. It currently carries a monetary award of 100,000 Swiss francs.
Recipients
1989: Louis de Branges (France / United States)
1991: Jean Bourgain (Belgium)
1993: Miklós Laczkovich (Hungary) and Marina Ratner (Russia / United States)
1995: Andrew J. Wiles (UK)
1997: Yuri V. Nesterenko (Russia) and Gilles I. Pisier (France)
1999: Alexander A. Beilinson (Russia / United States) and Helmut H. Hofer (Switzerland / United States)
2001: Henryk Iwaniec (Poland / United States) and Peter Sarnak (South Africa / United States) and Richard L. Taylor (UK / United States)
2003: Paul Seymour (UK)
2005: Ben Green (UK) and Terence Tao (Australia / United States)
2007: Oded Schramm (Israel / United States)
2009: Sorin Popa (Romania / United States)
2011: Ib Madsen (Denmark), David Preiss (UK) and Kannan Soundararajan (India / United States)
2013: Yitang Zhang (United States)
2015: Peter Scholze (Germany)
2017: Akshay Venkatesh (India / Australia)
2019: Assaf Naor (Israel / USA)
2
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https://en.wikipedia.org/wiki/Hugh%20Felkin
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Hugh Felkin (1922–2001) was a research chemist in France from 1950 to 1990 and a member of the Royal Society of Chemistry.
In 1967, he proposed a model to predict the stereochemical outcome of the addition of nucleophiles to carbonylic compounds. This model (now known as the Felkin-Anh model) differs slightly from Cram's rule and it is one of the most accepted rules to predict the outcome of these reactions.
He finished his career as Directeur de Recherche at the Institut de Chimie des Substances Naturelles in Gif-sur-Yvette. His laboratory worked on organometallic chemistry, with a special focus on organorhenium chemistry.
Born in England on 18 January 1922, he spent the second world war years in Geneva studying chemistry. At that time the requirements for a degree were "to show sufficient knowledge in chemistry".
After completing his studies, he went to France to work for the French National Centre for Scientific Research. In France he met Irène, born Elphimoff, also a research chemist, who became his wife and survived him by 9 years. They had one daughter, Mary, born in 1962.
He was a member of the communist party until the communist coup in Prague in 1948. After this disappointment, his sympathies still firmly inclined towards the left, he read Le Monde without which he used to say he didn't know what to think. Other sayings for which he was noted were "Je suis anti-sioniste mais je n'arrive pas à être pro-arabe", and in case of any uncertainty on the part of the pr
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https://en.wikipedia.org/wiki/Epson%20Robots
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EPSON Robots is the robotics design and manufacturing department of Japanese corporation Seiko Epson, the brand-name watch and computer printer producer.
Epson started the production of robots in 1980. Epson manufactures Cartesian, SCARA and 6-axis industrial robots for factory automation. Cleanroom and ESD compliant models are available.
They offer PC-based controllers and integrated vision systems utilizing Epson's own vision processing technology.
Epson has a 30-year heritage and there are more than 30,000 Epson robots installed in manufacturing industries around the world.
Epson uses a standardized PC-based controller for 6-axis robots, SCARA, and Linear Module needs. A move that simplifies support and reduces learning time.
Epson SCARA Robots
Epson offers four different lines of SCARA robots including the T-Series, G-Series, RS-Series, and LS-Series . The performance and features offered for each series of robot is determined by the intended purpose and needs of the robot. The T- Series robot is a high performance alternative to slide robots for pick-and-place operations. The G-Series offers a wide variety of robots in regards to the size, arm design, payload application, and more. The RS-Series offers two SCARA robots that are mounted from above and have the ability to move the second axis under the first axis. The LS-Series features several low cost and high performance robots that come in a variety of sizes.
References
External links
Official website
Robotics
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https://en.wikipedia.org/wiki/Robert%20C.%20Prim
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Robert Clay Prim III (September 25, 1921 – November 18, 2021) was an American mathematician and computer scientist.
Biography
Robert Clay Prim III was born in Sweetwater, Texas on September 25, 1921. In 1941, Prim received his B.S. in Electrical Engineering from The University of Texas at Austin, where he also met his wife Alice (Hutter) Prim (1921–2009), whom he married in 1942. Later in 1949, he received his Ph.D. in Mathematics from Princeton University, where he also worked as a research associate from 1948 until 1949.
During the climax of World War II (1941–1944), Prim worked as an engineer for General Electric. From 1944 until 1949, he was hired by the United States Naval Ordnance Lab as an engineer and later a mathematician. At Bell Laboratories, he served as director of mathematics research from 1958 to 1961. There, Prim developed Prim's algorithm. Also during his tenure at Bell Labs, Robert Prim assisted the Weapons Reliability Committee at Sandia National Laboratory chaired by Walter McNair in 1951. After Bell Laboratories, Prim became vice president of research at Sandia National Laboratories.
During his career at Bell Laboratories, Robert Prim along with coworker Joseph Kruskal developed two different algorithms (see greedy algorithm) for finding a minimum spanning tree in a weighted graph, a basic stumbling block in computer network design. His self-named algorithm, Prim's algorithm, was originally discovered in 1930 by mathematician Vojtěch Jarník and later i
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https://en.wikipedia.org/wiki/Gaspar%20Schott
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Gaspar Schott (German: Kaspar (or Caspar) Schott; Latin: Gaspar Schottus; 5 February 1608 – 22 May 1666) was a German Jesuit and scientist, specializing in the fields of physics, mathematics and natural philosophy, and known for his industry.
Biography
He was born at Bad Königshofen im Grabfeld. It is probable, but not certain, that his early education was at the Jesuit College at Würzburg. In any case, at the age of 19 he joined the Society of Jesus, entering the novitiate at Trier on 30 October 1627. After two years of novitiate training, he matriculated at the University of Würzburg on 6 November 1629 to begin a three-year study of Philosophy, following the normal academic path prescribed for Jesuit seminarians. Owing to the Swedish invasion of Würzburg in October 1631, the Jesuit community fled the city. Schott went, first to the Jesuit seminary of Tournai in Belgium, and subsequently, in 1633, to Caltagirone in Sicily, where he continued his study of Theology. After two years at Caltagirone, he was transferred to Palermo for his final year study of Theology after which, in 1637, he was ordained a priest. For the next fifteen years he held a range of teaching and pastoral positions in various Jesuit colleges in Sicily. In 1652, following correspondence with his old mathematics teacher at Würzburg, Fr. Athanasius Kircher, now an internationally acclaimed scholar at the Collegio Romano, Schott was transferred to the Collegio to work as Kircher's assistant. He was to spend
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https://en.wikipedia.org/wiki/Stabilizer%20%28chemistry%29
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In industrial chemistry, a stabilizer or stabiliser is a chemical that is used to prevent degradation.
Overview
Heat and light stabilizers are added to plastics because they ensure safe processing and protect products against aging and weathering. The trend is towards fluid systems, pellets, and increased use of masterbatches. There are monofunctional, bifunctional, and polyfunctional stabilizers. In economic terms the most important product groups on the market for stabilizers are compounds based on calcium (calcium-zinc and organo-calcium), lead, and tin stabilizers as well as liquid and light stabilizers (HALS, benzophenone, benzotriazole). Cadmium-based stabilizers largely vanished in the last years due to health and environmental concerns.
Polymers
Some kinds of stabilizers are:
antioxidants these prevent autoxidation of materials and come in 3 primary forms.
Oxygen scavengers (primarily phosphite esters such as tris(2,4-di-tert-butylphenyl)phosphite) are commonly used during the initial processing of the plastic.
Persistent radical scavengers prevent or slow the photo-oxidation of polymers. Traditionally these are alkylated phenols such as butylated hydroxytoluene but now also include hindered amine light stabilizers (HALS)
Antiozonants prevents or retards the degradation of polymers caused by ozone (ozone cracking)
sequestrants, forming chelate complexes and inactivating traces of metal ions that would otherwise act as catalysts
ultraviolet stabilizers are use
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https://en.wikipedia.org/wiki/Nanotechnology%20in%20fiction
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The use of nanotechnology in fiction has attracted scholarly attention. The first use of the distinguishing concepts of nanotechnology was "There's Plenty of Room at the Bottom", a talk given by physicist Richard Feynman in 1959. K. Eric Drexler's 1986 book Engines of Creation introduced the general public to the concept of nanotechnology. Since then, nanotechnology has been used frequently in a diverse range of fiction, often as a justification for unusual or far-fetched occurrences featured in speculative fiction.
Notable examples
Literature
In 1931, Boris Zhitkov wrote a short story called Microhands (Микроруки), where the narrator builds for himself a pair of microscopic remote manipulators, and uses them for fine tasks like eye surgery. When he attempts to build even smaller manipulators to be manipulated by the first pair, the story goes into detail about the problem of regular materials behaving differently on a microscopic scale.
In his 1956 short story The Next Tenants, Arthur C. Clarke describes tiny machines that operate at the micrometre scale – although not strictly nanoscale (billionth of a meter), they are the first fictional example of the concepts now associated with nanotechnology.
A concept similar to nanotechnology, called "micromechanical devices", was described in Lem's 1959 novel Eden These devices were used by the aliens as "seeds" to grow a wall around the human spaceship. <ref> Doktryna nieingerencji, In: Marek Oramus, Bogowie Lema</ref>
Stani
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https://en.wikipedia.org/wiki/Lower%20convex%20envelope
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In mathematics, the lower convex envelope of a function defined on an interval is defined at each point of the interval as the supremum of all convex functions that lie under that function, i.e.
See also
Convex hull
Lower envelope
Convex analysis
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https://en.wikipedia.org/wiki/List%20of%20Braunschweig%20University%20of%20Technology%20people
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Among the people who have taught or studied at the Braunschweig University of Technology or its precursor, the Collegium Carolinum, are the following:
Natural sciences and mathematics
Ewald Banse — Geography
Ernst Otto Beckmann — Chemistry
August Wilhelm Heinrich Blasius — Zoology and Botany
Johann Heinrich Blasius — Zoology
Rudolf Blasius — Bacteriology
Caesar Rudolf Boettger — Zoology
Victor von Bruns — Medicine
Lorenz Florenz Friedrich von Crell — Chemistry and Metallurgy
Julius Wilhelm Richard Dedekind — Mathematics
Carl Georg Oscar Drude — Botany
Manfred Eigen — Biophysical chemistry — Nobel Prize in Chemistry 1967
Theodor Engelbrecht — Physiology
Herbert Freundlich — Chemistry
Robert Fricke — Mathematics
Kurt Otto Friedrichs — Mathematics
Karl Theophil Fries — Chemistry
Gustav Gassner — Botany
Carl Friedrich Gauß — Mathematics
Karl Heinrich Gräffe — Mathematics
Heiko Harborth — Mathematics
Wolfgang Hahn — Mathematics
Robert Hartig — Forestry
Theodor Hartig — Forestry
Johann Christian Ludwig Hellwig — Entomology
Adolph Henke — Pharmacology
Wilhelm Henneberg — Chemistry
Nikolaus Hofreiter — Mathematics
Johann Karl Wilhelm Illiger — Zoology
Henning Kagermann — Physics
Klaus von Klitzing — Physics — Nobel Prize in Physics 1985
Friedrich Ludwig Knapp — Chemistry
August Wilhelm Knoch — Physics
William F. Martin — Botany
Rainer Moormann — Physical chemistry
Justus Mühlenpfordt — Nuclear physics
Adolph Nehrkorn — Ornithology
Agnes Pockels — Chemistry
Friedrich Carl Alwin Poc
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https://en.wikipedia.org/wiki/Peter%20Ward%20%28paleontologist%29
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Peter Douglas Ward (born May 12, 1949) is an American paleontologist and professor at the University of Washington, Seattle, and Sprigg Institute of Geobiology at the University of Adelaide. He has written numerous popular science works for a general audience and is also an adviser to the Microbes Mind Forum. In 2000, along with his co-author Donald E. Brownlee, he co-originated the term Rare Earth and developed the Medea hypothesis alleging that multicellular life is ultimately self-destructive.
Life and work
His parents, Joseph and Ruth Ward, moved to Seattle following World War II. Ward grew up in the Seward Park neighborhood of Seattle, attending Franklin High School, and he spent time during summers at a family summer cabin on Orcas Island.
Ward's academic career has included teaching posts and professional connections with Ohio State University, the NASA Astrobiology Institute, the University of California, McMaster University (where he received his PhD in 1976), and the California Institute of Technology. He was elected as a Fellow of the California Academy of Sciences in 1984.
Ward specializes in the Cretaceous–Paleogene extinction event, the Permian–Triassic extinction event, and mass extinctions generally. He has published books on biodiversity and the fossil record. His 1992 book On Methuselah's Trail received a "Golden Trilobite Award" from the Paleontological Society as the best popular science book of the year. Ward also serves as an adjunct professor of zoo
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https://en.wikipedia.org/wiki/Regular%20singular%20point
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In mathematics, in the theory of ordinary differential equations in the complex plane , the points of are classified into ordinary points, at which the equation's coefficients are analytic functions, and singular points, at which some coefficient has a singularity. Then amongst singular points, an important distinction is made between a regular singular point, where the growth of solutions is bounded (in any small sector) by an algebraic function, and an irregular singular point, where the full solution set requires functions with higher growth rates. This distinction occurs, for example, between the hypergeometric equation, with three regular singular points, and the Bessel equation which is in a sense a limiting case, but where the analytic properties are substantially different.
Formal definitions
More precisely, consider an ordinary linear differential equation of -th order
with meromorphic functions.
The equation should be studied on the Riemann sphere to include the point at infinity as a possible singular point. A Möbius transformation may be applied to move ∞ into the finite part of the complex plane if required, see example on Bessel differential equation below.
Then the Frobenius method based on the indicial equation may be applied to find possible solutions that are power series times complex powers near any given in the complex plane where need not be an integer; this function may exist, therefore, only thanks to a branch cut extending out from , or on a
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https://en.wikipedia.org/wiki/Thanasis%20Papakonstantinou
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Athanasios "Thanasis" Papakonstantinou (; born 26 April 1959) is a Greek singer-songwriter.
Short biography
He is married, with two children. Papakonstantinou studied mechanical engineering in Thessaloniki, which he practices as well as being a musician. After military service (all males are conscripted in Greece), he had a spell of handcrafting traditional Greek musical instruments.
Now a Larissa resident, Papakonstantinou has established himself as one of the most original and prolific people in the Greek music scene. He writes music in the Greek folk idiom, stemming from his own recollections of traditional songs his parents sang while working in the field. He usually writes his own lyrics or uses poems. He has collaborated with numerous notable artists from the Greek music scene, such as Giannis Aggelakas, Melina Kana, Sokratis Malamas, Lizeta Kalimeri, Nikos Papazoglou.
In 2002, his song Nanourisma was featured in the film by Nikos Grammatikos O Vasilias (The King). The 2007 documentary The Horns of the Bull is dedicated to Papakonstantinou's work.
Discography
Αγία Νοσταλγία (Holy Nostalgia, Agia Nostalgia) (1993)
Στην Ανδρομέδα και στη Γη (In Andromeda and on Earth, Stin Andromeda kai sti Gi) (1995)
Της Αγάπης Γερακάρης (Falconer of Love, Tis Agapis Gerakaris) (1996)
Λάφυρα (Loot, Lafyra) (1998)
Βραχνός Προφήτης (Hoarse Prophet, Vrachnos Profitis) (2000)
Αγρύπνια (Vigil, Agrypnia) (2002)
Τα ζωντανά (The Live Ones, Ta Zontana) (2004)
Οι πρώτες ηχογραφήσεις (T
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https://en.wikipedia.org/wiki/Francesco%20Paolo%20Cantelli
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Francesco Paolo Cantelli (20 December 187521 July 1966) was an Italian mathematician. He made contributions to celestial mechanics, probability theory, and actuarial science.
Biography
Cantelli was born in Palermo. He received his doctorate in mathematics in 1899 from the University of Palermo with a thesis on celestial mechanics and continued his interest in astronomy by working until 1903 at Palermo Astronomical Observatory (osservatorio astronomico cittadino), which was under the direction of Annibale Riccò. Cantelli's early papers were on problems in astronomy and celestial mechanics.
From 1903 to 1923 Cantelli worked at the Istituto di Previdenza della Cassa Depositi e Prestiti (Pension Fund for the Government Deposits and Loans Bank). During these years he did research on the mathematics of finance theory and actuarial science, as well as the probability theory. Cantelli's later work was all on probability theory. Borel–Cantelli lemma, Cantelli's inequality and the Glivenko–Cantelli theorem are result of his work in this field. In 1916–1917 he made contributions to the theory of stochastic convergence. In 1923 he resigned his actuarial position when he was appointed professor of actuarial mathematics at the University of Catania. From there, he went to the University of Naples, where he worked as a professor and then in 1931 to the Sapienza University of Rome where he remained until his retirement in 1951. He died in Rome.
Cantelli made fundamental contributions t
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https://en.wikipedia.org/wiki/Smoluchowski%20coagulation%20equation
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In statistical physics, the Smoluchowski coagulation equation is a population balance equation introduced by Marian Smoluchowski in a seminal 1916 publication, describing the time evolution of the number density of particles as they coagulate (in this context "clumping together") to size x at time t.
Simultaneous coagulation (or aggregation) is encountered in processes involving polymerization, coalescence of aerosols, emulsication, flocculation.
Equation
The distribution of particle size changes in time according to the interrelation of all particles of the system. Therefore, the Smoluchowski coagulation equation is an integrodifferential equation of the particle-size distribution. In the case when the sizes of the coagulated particles are continuous variables, the equation involves an integral:
If dy is interpreted as a discrete measure, i.e. when particles join in discrete sizes, then the discrete form of the equation is a summation:
There exists a unique solution for a chosen kernel function.
Coagulation kernel
The operator, K, is known as the coagulation kernel and describes the rate at which particles of size coagulate with particles of size . Analytic solutions to the equation exist when the kernel takes one of three simple forms:
known as the constant, additive, and multiplicative kernels respectively. For the case it could be mathematically proven that the solution of Smoluchowski coagulation equations have asymptotically the dynamic scaling prope
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https://en.wikipedia.org/wiki/SkyMapper
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SkyMapper is a fully automated 1.35 m (4.4 ft) wide-angle optical telescope at Siding Spring Observatory in northern New South Wales, Australia. It is one of the telescopes of the Research School of Astronomy and Astrophysics of the Australian National University (ANU). The telescope has a compact modified Cassegrain design with a large 0.69 m secondary mirror, which gives it a very wide field of view: its single, dedicated instrument, a 268-million pixel imaging camera, can photograph 5.7 square degrees of sky. The camera has six light filters which span from ultraviolet to near infrared wavelengths.
The SkyMapper telescope was built to carry out the Southern Sky Survey, which will image the entire southern sky several times over in SkyMapper's six spectral filters over the course of five years. This survey will be analogous to the Sloan Digital Sky Survey of the Northern hemisphere sky. It has several enhancements, including temporal coverage, more precise measurements of stellar properties and coverage of large parts of the plane of the Galaxy.
The telescope and its camera were built by the ANU as a successor to the Great Melbourne Telescope at Mount Stromlo after that telescope was burnt in the 2003 Canberra bushfires. It was inaugurated by Minister Kim Carr and Governor of New South Wales Marie Bashir in 2009. The survey project is funded by the Australian Research Council through various grants. The project was also a finalist in The Australian's 2011 Innovation Chal
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https://en.wikipedia.org/wiki/Camborne%20School%20of%20Mines
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Camborne School of Mines (), commonly abbreviated to CSM, was founded in 1888. Its research and teaching is related to the understanding and management of the Earth's natural processes, resources and the environment. It has undergraduate, postgraduate and research degree programmes within the Earth resources, civil engineering and environmental sectors. CSM is located at the Penryn Campus, near Falmouth, Cornwall, UK. The school merged with the University of Exeter in 1993.
Reputation
Camborne School of Mines has an international reputation in mining, tunnelling, mineralogy, mineral economics, geology, geophysics and geochemistry. CSM's international reputation dates back to the 19th century when with new deposits found around the world CSM graduates began to seek employment overseas and by the 20th century, graduates were in most of the world's major mining areas such as Southern Africa, Western Africa, Malaysia, Australia, South America, Mexico, United States and Canada.
Through CSM's teaching, research and the CSM Association's (CSM alumni) network CSM maintains a strong presence in the global mining industry.
Teaching
As of 2023, undergraduate degrees available included a BEng degree in mining engineering (the only one offered in the UK), and BSc programmes in applied geology, and in engineering geology and geotechnics. The postgraduate MSc degrees included applied geotechnics, minerals engineering, mining engineering, mining geology, and surveying and land/environme
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https://en.wikipedia.org/wiki/Ultrahydrophobicity
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In chemistry and materials science, ultrahydrophobic (or superhydrophobic) surfaces are highly hydrophobic, i.e., extremely difficult to wet. The contact angles of a water droplet on an ultrahydrophobic material exceed 150°. This is also referred to as the lotus effect, after the superhydrophobic leaves of the lotus plant. A droplet striking these kinds of surfaces can fully rebound like an elastic ball. Interactions of bouncing drops can be further reduced using special superhydrophobic surfaces that promote symmetry breaking, pancake bouncing or waterbowl bouncing.
Theory
In 1805, Thomas Young defined the contact angle θ by analysing the forces acting on a fluid droplet resting on a smooth solid surface surrounded by a gas.
where
= Interfacial tension between the solid and gas
= Interfacial tension between the solid and liquid
= Interfacial tension between the liquid and gas
θ can be measured using a contact angle goniometer.
Wenzel determined that when the liquid is in intimate contact with a microstructured surface, θ will change to θW*
where r is the ratio of the actual area to the projected area. Wenzel's equation shows that microstructuring a surface amplifies the natural tendency of the surface. A hydrophobic surface (one that has an original contact angle greater than 90°) becomes more hydrophobic when microstructured – its new contact angle becomes greater than the original. However, a hydrophilic surface (one that has an original contact angle less than 9
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https://en.wikipedia.org/wiki/Alkylimino-de-oxo-bisubstitution
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In organic chemistry, alkylimino-de-oxo-bisubstitution is the organic reaction of carbonyl compounds with amines to imines. The reaction name is based on the IUPAC Nomenclature for Transformations. The reaction is acid catalyzed and the reaction type is nucleophilic addition of the amine to the carbonyl compound followed by transfer of a proton from nitrogen to oxygen to a stable hemiaminal or carbinolamine. With primary amines water is lost in an elimination reaction to an imine. With aryl amines especially stable Schiff bases are formed.
Reaction mechanism
The reaction steps are reversible reactions and the reaction is driven to completion by removal of water e.g. by azeotropic distillation, molecular sieves or titanium tetrachloride. Primary amines react through an unstable hemiaminal intermediate which then splits off water.
Secondary amines do not lose water easily because they do not have a proton available and instead they often react further to an aminal:
or when an α-carbonyl proton is present to an enamine:
In acidic environment the reaction product is an iminium salt by loss of water.
This reaction type is found in many Heterocycle preparations for example the Povarov reaction and the Friedländer-synthesis to quinolines.
Because both components are so reactive a molecule does not carry an aldehyde and an amine group at the same time unless the amine group is fitted with a protective group. As a further demonstration of reactivity one study explored the pro
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https://en.wikipedia.org/wiki/Pitching%20machine
|
A pitching machine is a machine that automatically pitches a baseball to a batter at different speeds and styles. Most machines are hand-fed, but there are some that automatically feed. There are multiple types of pitching machines; softball, baseball, youth, adult, and a combination of both softball and baseball.
History
In 1897, mathematics instructor Charles Hinton designed a gunpowder-powered baseball pitching machine for the Princeton University baseball team's batting practice. According to one source it caused several injuries, and may have been in part responsible for Hinton's dismissal from Princeton that year. However, the machine was versatile: it was capable of throwing variable speeds with an adjustable breech size and firing curve balls by the use of two rubber-coated steel fingers at the muzzle of the pitcher. Hinton successfully introduced the machine to the University of Minnesota where he worked as an assistant professor until 1900.
The arm-type pitching machine was designed by Paul Giovagnoli in 1952, for use on his driving range. Using a metal arm mounted to a large gear, this type of machine simulates the motion of an actual pitcher, throwing balls with consistent speed and direction. One- and two-wheel style machines were originally patented by Bartley N. Marty in 1916.
Design
Pitching machines come in a variety of styles. However, the two most popular machines are an arm action machine and a circular wheel machine. The arm action machine simulates th
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https://en.wikipedia.org/wiki/Generator%20%28mathematics%29
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In mathematics and physics, the term generator or generating set may refer to any of a number of related concepts. The underlying concept in each case is that of a smaller set of objects, together with a set of operations that can be applied to it, that result in the creation of a larger collection of objects, called the generated set. The larger set is then said to be generated by the smaller set. It is commonly the case that the generating set has a simpler set of properties than the generated set, thus making it easier to discuss and examine. It is usually the case that properties of the generating set are in some way preserved by the act of generation; likewise, the properties of the generated set are often reflected in the generating set.
List of generators
A list of examples of generating sets follow.
Generating set or spanning set of a vector space: a set that spans the vector space
Generating set of a group: A subset of a group that is not contained in any subgroup of the group other than the entire group
Generating set of a ring: A subset S of a ring A generates A if the only subring of A containing S is A
Generating set of an ideal in a ring
Generating set of a module
A generator, in category theory, is an object that can be used to distinguish morphisms
In topology, a collection of sets that generate the topology is called a subbase
Generating set of a topological algebra: S is a generating set of a topological algebra A if the smallest closed subalg
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https://en.wikipedia.org/wiki/Integral%20symbol
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The integral symbol:
is used to denote integrals and antiderivatives in mathematics, especially in calculus.
History
The notation was introduced by the German mathematician Gottfried Wilhelm Leibniz in 1675 in his private writings; it first appeared publicly in the article "" (On a hidden geometry and analysis of indivisibles and infinites), published in Acta Eruditorum in June 1686. The symbol was based on the ſ (long s) character and was chosen because Leibniz thought of the integral as an infinite sum of infinitesimal summands.
Typography in Unicode and LaTeX
Fundamental symbol
The integral symbol is in Unicode and \int in LaTeX. In HTML, it is written as ∫ (hexadecimal), ∫ (decimal) and ∫ (named entity).
The original IBM PC code page 437 character set included a couple of characters ⌠ and ⌡ (codes 244 and 245 respectively) to build the integral symbol. These were deprecated in subsequent MS-DOS code pages, but they still remain in Unicode (U+2320 and U+2321 respectively) for compatibility.
The ∫ symbol is very similar to, but not to be confused with, the letter ʃ ("esh").
Extensions of the symbol
Related symbols include:
Typography in other languages
In other languages, the shape of the integral symbol differs slightly from the shape commonly seen in English-language textbooks. While the English integral symbol leans to the right, the German symbol (used throughout Central Europe) is upright, and the Russian variant leans slightly to the
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https://en.wikipedia.org/wiki/Selectable%20marker
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A selectable marker is a gene introduced into a cell, especially a bacterium or to cells in culture, that confers a trait suitable for artificial selection. They are a type of reporter gene used in laboratory microbiology, molecular biology, and genetic engineering to indicate the success of a transfection or other procedure meant to introduce foreign DNA into a cell. Selectable markers are often antibiotic resistance genes (An antibiotic resistance marker is a gene that produces a protein that provides cells expressing this protein with resistance to an antibiotic.). Bacteria that have been subjected to a procedure to introduce foreign DNA are grown on a medium containing an antibiotic, and those bacterial colonies that can grow have successfully taken up and expressed the introduced genetic material.
Normally the genes encoding resistance to antibiotics such as ampicillin, chloramphenicol, tetracycline or kanamycin, etc., are considered useful selectable markers for E. coli.
Modus operandi
The non-recombinants are separated from recombinants; i.e., a r-DNA is introduced in bacteria, some bacteria are successfully transformed some remain non-transformed. When grown on medium containing ampicillin, bacteria die due to lack of ampicillin resistance. The position is later noted on nitrocellulose paper and separated out to move them to nutrient medium for mass production of required product.
An alternative to a selectable marker is a screenable marker which can also be denoted
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https://en.wikipedia.org/wiki/Tagma
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Tagma (from Greek τάγμα "something which has been ordered or arranged"; plural tagmata) may refer to:
Tagma (biology), a grouping of segments, usually in arthropod anatomy
Tagma (military), a subdivision of the Byzantine army
Tagma (τάγμα), the Modern Greek term for an order (honour)
Moha Tagma (born 1954), Moroccan diplomat
See also
Tagmeme (linguistics)
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https://en.wikipedia.org/wiki/Tagma%20%28biology%29
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In biology, a tagma (Greek: τάγμα, : tagmata – τάγματα - body of soldiers; battalion) is a specialized grouping of multiple segments or metameres into a coherently functional morphological unit. Familiar examples are the head, the thorax, and the abdomen of insects. The segments within a tagma may be either fused (such as in the head of an insect) or so jointed as to be independently moveable (such as in the abdomen of most insects).
Usually the term is taken to refer to tagmata in the morphology of members of the phylum Arthropoda, but it applies equally validly in other phyla, such as the Chordata.
In a given taxon the names assigned to particular tagmata are in some sense informal and arbitrary; for example, not all the tagmata of species within a given subphylum of the Arthropoda are homologous to those of species in other subphyla; for one thing they do not all comprise corresponding somites, and for another, not all the tagmata have closely analogous functions or anatomy. In some cases this has led to earlier names for tagmata being more or less successfully superseded. For example, the one-time terms "cephalothorax" and "abdomen" of the Araneae, though not yet strictly regarded as invalid, are giving way to prosoma and opisthosoma. The latter two terms carry less of a suggestion of homology with the significantly different tagmata of insects.
Tagmosis
The development of distinct tagmata is believed to be a feature of the evolution of segmented animals, especially a
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https://en.wikipedia.org/wiki/Methylisopropyltryptamine
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N-Methyl-N-isopropyltryptamine (MiPT) is a psychedelic tryptamine, closely related to DMT, DiPT and Miprocin.
Chemistry
MiPT base, unlike many other tryptamines in their freebase form, does not decompose rapidly in the presence of light or oxygen.
In August 2019, Chadeayne et al. solved the crystal structure of MiPT fumarate. Its systematic name is [2-(1H-indol-3-yl)ethyl](methyl)propan-2-ylazanium 3-carboxyprop-2-enoate. The salt consists of a protonated tryptammonium cation and a 3-carboxyacrylate (hydrogen fumarate) anion in the asymmetric unit.
Dosage
10-25 mg is usually taken orally, with effects lasting 4–6 hours.
Effects
MiPT is said to emphasize psychedelic/entheogenic effects over sensory/hallucinogenic activity. Users report strong mental effects, but few perceptual alterations.
Hyper sensitivity to sound as well
Legality
Sweden's public health agency suggested classifying MiPT as a hazardous substance, on May 15, 2019.
In the United States MiPT is considered a schedule 1 controlled substance as a positional isomer of Diethyltryptamine (DET). MiPT is specifically mentioned by name in the DEA Controlled Substance Orange Book.
See also
DiPT
5-MeO-MiPT
TiHKAL
References
External links
TiHKAL entry
MiPT Entry in TiHKAL • info
Erowid vault
Psychedelic tryptamines
Designer drugs
Serotonin receptor agonists
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https://en.wikipedia.org/wiki/Sonochemistry
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In chemistry, the study of sonochemistry is concerned with understanding the effect of ultrasound in forming acoustic cavitation in liquids, resulting in the initiation or enhancement of the chemical activity in the solution. Therefore, the chemical effects of ultrasound do not come from a direct interaction of the ultrasonic sound wave with the molecules in the solution.
History
The influence of sonic waves travelling through liquids was first reported by Robert Williams Wood (1868–1955) and Alfred Lee Loomis (1887–1975) in 1927. The experiment was about the frequency of the energy that it took for sonic waves to "penetrate" the barrier of water. He came to the conclusion that sound does travel faster in water, but because of the water's density compared to earth's atmosphere it was incredibly hard to get the sonic waves to couple their energy into the water. Due to the sudden density change, much of the energy is lost, similar to shining a flashlight towards a piece of glass; some of the light is transmitted into the glass, but much of it is lost to reflection outwards. Similarly with an air-water interface, almost all of the sound is reflected off the water, instead of being transmitted into it. After much research they decided that the best way to disperse sound into the water was to create bubbles at the same time as the sound. Another issue was the ratio of the amount of time it took for the lower frequency waves to penetrate the bubbles walls and access the water aro
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https://en.wikipedia.org/wiki/Rollin%20C.%20Richmond
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Rollin Charles Richmond was the president of Humboldt State University in Arcata, California from May 2002 to July 2014. Before taking that position he was provost and genetics professor at Iowa State University, leading research on the genetic mechanisms of fruit flies evolution and effects of cocaine on Drosophila. He has also served in various positions at the State University of New York at Stony Brook, the University of South Florida, and Indiana University.
The November 7, 2007 issue of the Humboldt State University weekly student-run paper, The Lumberjack, reported that the Academic Senate at HSU voted by 56% to issue a vote of no confidence in Rollin Richmond's leadership.
Under his leadership Humboldt State University was recently reaccredited for ten years (maximum possible) by the Western Association of Schools and Colleges. They noted that significant change must occur at Humboldt State including a reformulation of shared governance.
References
External links
Richmond's abridged curriculum vitae
Living people
California State Polytechnic University, Humboldt people
Iowa State University faculty
Stony Brook University faculty
University of South Florida faculty
Indiana University faculty
Heads of universities and colleges in the United States
American geneticists
Year of birth missing (living people)
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https://en.wikipedia.org/wiki/Arthur%20Ashkin
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Arthur Ashkin (September 2, 1922 – September 21, 2020) was an American scientist and Nobel laureate who worked at Bell Laboratories and Lucent Technologies. Ashkin has been considered by many as the father of optical tweezers,
for which he was awarded the Nobel Prize in Physics 2018 at age 96, becoming the oldest Nobel laureate until 2019 when John B. Goodenough was awarded at 97. He resided in Rumson, New Jersey.
Ashkin started his work on manipulation of microparticles with laser light in the late 1960s which resulted in the invention of optical tweezers in 1986. He also pioneered the optical trapping process that eventually was used to manipulate atoms, molecules, and biological cells. The key phenomenon is the radiation pressure of light; this pressure can be dissected down into optical gradient and scattering forces.
Early life and family
Arthur Ashkin was born in Brooklyn, New York, in 1922, to a family of Ukrainian-Jewish background. His parents were Isadore and Anna Ashkin. He had two siblings, a brother, Julius, also a physicist, and a sister, Ruth. One older sibling, Gertrude, died while young. The family home was in Brooklyn, New York, at 983 E 27 Street. Isadore (né Aschkinase) had emigrated to the United States from Odessa (then Russian Empire, now Ukraine), at the age of 18. Anna, five years younger, also came from today's Ukraine, then Galicia, Austro-Hungarian Empire. Within a decade of his landing in New York, Isadore had become a U.S. citizen and was run
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https://en.wikipedia.org/wiki/PQS%20%28software%29
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PQS is a general purpose quantum chemistry program. Its roots go back to the first ab initio gradient program developed in Professor Peter Pulay's group but now it is developed and distributed commercially by Parallel Quantum Solutions. There is a reduction in cost for academic users and a site license. Its strong points are geometry optimization, NMR chemical shift calculations, and large MP2 calculations, and high parallel efficiency on computing clusters. It includes many other capabilities including Density functional theory, the semiempirical methods, MINDO/3, MNDO, AM1 and PM3, Molecular mechanics using the SYBYL 5.0 Force Field, the quantum mechanics/molecular mechanics mixed method using the ONIOM method, natural bond orbital (NBO) analysis and COSMO solvation models. Recently, a highly efficient parallel CCSD(T) code for closed shell systems has been developed. This code includes many other post Hartree–Fock methods: MP2, MP3, MP4, CISD, CEPA, QCISD and so on.
History
The origin of PQS program was developed by Meyer and Pulay in the late 1960s. They both were at the Max-Planck Institute for Physics and Astrophysics in Munich when they began to write a new ab initio program. The main purpose was to establish new ab initio techniques. Pulay and Meyer had slightly different interests. Pulay was interested in implementing gradient geometry optimization, analytical energy derivatives (force), and force constant calculations via the numerical differentiation of analytica
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https://en.wikipedia.org/wiki/Free%20Lie%20algebra
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In mathematics, a free Lie algebra over a field K is a Lie algebra generated by a set X, without any imposed relations other than the defining relations of alternating K-bilinearity and the Jacobi identity.
Definition
The definition of the free Lie algebra generated by a set X is as follows:
Let X be a set and a morphism of sets (function) from X into a Lie algebra L. The Lie algebra L is called free on X if is the universal morphism; that is, if for any Lie algebra A with a morphism of sets , there is a unique Lie algebra morphism such that .
Given a set X, one can show that there exists a unique free Lie algebra generated by X.
In the language of category theory, the functor sending a set X to the Lie algebra generated by X is the free functor from the category of sets to the category of Lie algebras. That is, it is left adjoint to the forgetful functor.
The free Lie algebra on a set X is naturally graded. The 1-graded component of the free Lie algebra is just the free vector space on that set.
One can alternatively define a free Lie algebra on a vector space V as left adjoint to the forgetful functor from Lie algebras over a field K to vector spaces over the field K – forgetting the Lie algebra structure, but remembering the vector space structure.
Universal enveloping algebra
The universal enveloping algebra of a free Lie algebra on a set X is the free associative algebra generated by X. By the Poincaré–Birkhoff–Witt theorem it is the "same size" as the symm
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https://en.wikipedia.org/wiki/Lawrence%20Paulson
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Lawrence Charles Paulson (born 1955) is an American computer scientist. He is a Professor of Computational Logic at the University of Cambridge Computer Laboratory and a Fellow of Clare College, Cambridge.
Education
Paulson graduated from the California Institute of Technology in 1977, and obtained his PhD in Computer Science from Stanford University in 1981 for research on programming languages and compiler-compilers supervised by John L. Hennessy.
Research
Paulson came to the University of Cambridge in 1983 and became a Fellow of Clare College, Cambridge in 1987. He is best known for the cornerstone text on the programming language ML, ML for the Working Programmer. His research is based around the interactive theorem prover Isabelle, which he introduced in 1986. He has worked on the verification of cryptographic protocols using inductive definitions, and he has also formalised the constructible universe of Kurt Gödel. Recently he has built a new theorem prover, MetiTarski, for real-valued special functions.
Paulson teaches an undergraduate lecture course in the Computer Science Tripos, entitled Logic and Proof which covers automated theorem proving and related methods. (He used to teach Foundations of Computer Science which introduces functional programming, but this course was taken over by Alan Mycroft and Amanda Prorok in 2017, and then Anil Madhavapeddy and Amanda Prorok in 2019.)
Awards and honours
Paulson was elected a Fellow of the Royal Society (FRS) in 2017,
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https://en.wikipedia.org/wiki/Antonio%20Lazcano
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Antonio Eusebio Lazcano Araujo Reyes (born 1950) is a Mexican biology researcher and professor of the School of Sciences at the National Autonomous University of Mexico in Mexico City. He has studied the origin and early evolution of life for more than 35 years.
Lazcano pursued his undergraduate and graduate studies focused on the study of prebiotic evolution and the emergence of life. He has been professor-in-residence or visiting scientist in France, Spain, Cuba, Switzerland, Russia, and the United States. He has written several books in Spanish, including The Origin of Life (1984) which became a best-seller with more than 600,000 sold copies.In addition, he has been a member of several advisory and review boards of scientific organizations, such as NASA, where he was a member of the NASA Astrobiology Institute
He served as president of the International Society for the Study of the Origin of Life, for two terms, and is also the first Latin American scientist to occupy this position. A great honor, for Alexander Oparin, Stanley L. Miller and J. William Schopf, were also presidents of ISSOL.
Lazcano has devoted considerable efforts to promote scientific journalism and teaching. He also promotes the study of evolutionary biology and the origins of life, all over the world.
Bibliography
Lazcano Araujo, Antonio, El origen del nucleocitoplasma. Breve historia de una hipótesis cambiante, incluido en Una revolución en la evolución (A revolution in evolution), Universitat V
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https://en.wikipedia.org/wiki/Bredt%27s%20rule
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In organic chemistry, Bredt's rule is an empirical observation that states that a double bond cannot be placed at the bridgehead of a bridged ring system, unless the rings are large enough. The rule is named after Julius Bredt, who first discussed it in 1902 and codified it in 1924. It primarily relates to bridgeheads with carbon-carbon and carbon-nitrogen double bonds.
For example, two of the following isomers of norbornene violate Bredt's rule, which makes them too unstable to prepare:
In the figure, the bridgehead atoms involved in Bredt's rule violation are highlighted in red.
Bredt's rule is a consequence of the fact that having a double bond on a bridgehead, carbons from which three bonds radiate and which the rings share a single covalent bond, would be equivalent to having a trans double bond on a ring, which is not stable for small rings (fewer than eight atoms) due to a combination of ring strain, and angle strain (nonplanar alkene). The p orbitals of the bridgehead atom and adjacent atoms are orthogonal and thus are not aligned properly for the formation of pi bonds. Fawcett quantified the rule by defining S as the number of non-bridgehead atoms in a ring system, and postulated that stability required S ≥ 9 in bicyclic systems and S ≥ 11 in tricyclic systems. There has been an active research program to seek compounds inconsistent with the rule, and for bicyclic systems a limit of S ≥ 7 is now established with several such compounds having been prepared. The
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https://en.wikipedia.org/wiki/5-MeO-DPT
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5-MeO-DPT (also known as 5-methoxy-N,N-Dipropyltryptamine), is a psychedelic and entheogenic designer drug.
Chemistry
The full chemical name is N-[2-(5-methoxy-1H-indol-3-yl)ethyl]-N-propylpropan-1-amine. It is classified as a tryptamine derivative.
Effects
Little is known about the subjective effects of 5-MeO-DPT, but the nature of the compound is probably comparable to 5-MeO-DiPT, 5-MeO-DMT, or DPT, which are also psychedelic tryptamines/indoles. However, the duration of the above-mentioned drugs vary considerably.
Dosage
5-MeO-DPT is orally active, with 3-10 mg representing a fully effective dosage for most users. Effects begin within three hours, and usually last 4 hours.
Legality
In the United States 5-MeO-DPT is considered a schedule 1 controlled substance as a positional isomer of 5-Methoxy-N,N-diisopropyltryptamine (5-MeO-DiPT)
See also
5-MeO-DALT
5-MeO-DET
5-MeO-DBT
5-MeO-EPT
References
External links
5-MeO-DET TiHKAL Entry on Erowid, mentioning 5-MeO-DPT
5-MeO-DPT on Erowid
Mexamines
Psychedelic tryptamines
Designer drugs
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https://en.wikipedia.org/wiki/Jacquelynn%20Berube
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Jacquelynn Ann Berube (born December 9, 1971) is an American weightlifter who competed in the women's 58 kg at the 2005 World Championships in Doha, Qatar and reached the 7th spot with 198 kg in total.
Education
Berube obtained her bachelor's degree from the University of Wisconsin–La Crosse and her master's degree in biology from the University of Colorado. During her time at the University of Wisconsin–La Crosse, Berube became an Academic All-American gymnast. She also competed on the varsity men's wrestling team in the 118 pound weight class.
Clubs
Pinnacle Weightlifting
About
Berube competed in weightlifting competitions at 58 kg standing at 5 feet tall. She was coached by Zygmunt Smalcez. After she graduated from college, Berube wrestled on the USA Women's National Wrestling Team where she won a silver medal at the World Championships in 1996. Two years later, she became the strength and conditioning coach at Northwestern University and focused all of her attention on weightlifting. Prior to the 2006 World Weightlifting Championships, Berube had a weight fall on her leg and it ruptured her quad. Soon after, she competed in the Dominican Republic and took 11th place. Berube had surgery to help her ruptured quad. After her quad healed, she competed in the Pan American Games in Rio de Janeiro, Brazil. Berube's favorite competition lift is the snatch and her favorite training lift is the squat.
Sources
Weightlifting Exchange http://weightliftingexchange.com/index.php?op
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https://en.wikipedia.org/wiki/Gold%20cluster
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Gold clusters in cluster chemistry can be either discrete molecules or larger colloidal particles. Both types are described as nanoparticles, with diameters of less than one micrometer. A nanocluster is a collective group made up of a specific number of atoms or molecules held together by some interaction mechanism. Gold nanoclusters have potential applications in optoelectronics and catalysis.
Bare gold clusters
Bare gold clusters, i.e., clusters without stabilizing ligand shells can be synthesized and studied in vacuum using molecular beam techniques. Their structures have been experimentally studied using, e.g., anion photoelectron spectroscopy, far-infrared spectroscopy, as well as measurements of their ion mobility and electron diffraction studies in conjunction with quantum chemical calculations. The structures of such clusters differ strongly from those of the ligand-stabilized ones, indicating an pivotal influence of the chemical environment on the cluster structure. A notable example is Au20 which forms a perfect tetrahedron in which the Au atom packing closely resembles the atomic arrangement in the fcc bulk structure of metallic gold. Evidence has been presented for the existence of hollow golden cages with the partial formula with n = 16 to 18. These clusters, with diameter of 550 picometres, are generated by laser vaporization and characterized by photoelectron spectroscopy.
Structure of ligand-stabilized Au clusters
Bulk gold exhibits a face-centered cub
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https://en.wikipedia.org/wiki/Anura
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Anura may refer to:
Biology
Anura (frog), the order for frogs
Anura (plant), a genus of flowering plants in the daisy family
People
Anura is a common given name in Sri Lanka
Anura Bandaranaike (1949–2008), Sri Lankan politician
Anura Kumara Dissanayaka (born 1968), Sri Lankan politician
Anura Horatious, Sri Lankan novelist
Anura C. Perera (born 1947), Sri Lankan-American writer and astronomer
Anura Ranasinghe (1956–1998), Sri Lankan cricketer
Anura Rohana, Sri Lankan golfer
Anura Tennekoon (born 1946), Sri Lankan cricketer
Anura Wegodapola (born 1981), cricketer for Sri Lanka Navy
Anura Priyadharshana Yapa (born 1959), Sri Lankan politician
Place
Anura, Varanasi, a village in Uttar Pradesh, India
See also
Aruna (disambiguation)
Taxonomy disambiguation pages
Sinhalese masculine given names
Sinhalese given names
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https://en.wikipedia.org/wiki/Lola%20%28computing%29
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Lola is designed to be a simple hardware description language for describing synchronous, digital circuits. Niklaus Wirth developed the language to teach digital design on field-programmable gate arrays (FPGAs) to computer science students while a professor at ETH Zurich.
The purpose of Lola is to statically describe the structure and function of hardware components and of the connections between them. A Lola text is composed of declarations and statements. It describes digital electronics hardware on the logic gate level in the form of signal assignments. Signals are combined using operators and assigned to other signals. Signals and the respective assignments can be grouped together into data types. An instance of a type is a hardware component. Types can be composed of instances of other types, thereby supporting a hierarchical design style and they can be generic, e.g., parametrizable with the word width of a circuit.
All of the concepts mentioned above are demonstrated in the following example of a circuit for adding binary data. First, a fundamental building block () is defined, then this is used to declare a cascade of word-width 8, and finally the s are connected to each other. The defined in this example can serve as a building block on a higher level of the design hierarchy.
MODULE Adder;
TYPE Cell; (* Composite Type *)
IN x,y,ci:BIT; (* input signals *)
OUT z,co:BIT; (* output signals *)
BEGIN
z:=x-y-ci;
co:=x*y+x*ci+y*ci;
END Cell;
CONST N:=8;
IN X
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https://en.wikipedia.org/wiki/Edgar%20Buckingham
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Edgar Buckingham (July 8, 1867 in Philadelphia, Pennsylvania – April 29, 1940 in Washington DC) was an American physicist.
He graduated from Harvard University with a bachelor's degree in physics in 1887. He did graduate work at Strasbourg and then studied under the chemist Wilhelm Ostwald at Leipzig, from which he was granted a PhD in 1893. He worked at the USDA Bureau of Soils from 1902 to 1906 as a soil physicist. He worked at the (US) National Bureau of Standards (now the National Institute of Standards and Technology, or NIST) 1906–1937. His fields of expertise included soil physics, gas properties, acoustics, fluid mechanics, and blackbody radiation. He is also the originator of the Buckingham theorem in the field of dimensional analysis.
In 1923, Buckingham published a report which voiced skepticism that jet propulsion would be economically competitive with prop driven aircraft at low altitudes and at the speeds of that period.
Buckingham's first work on soil physics is on soil aeration, particularly the loss of carbon dioxide from the soil and its subsequent replacement by oxygen. From his experiments he found that the rate of gas diffusion in soil was not dependent significantly on the soil structure, compactness or water content of the soil. Using an empirical formula based on his data, Buckingham was able to give the diffusion coefficient as a function of air content. This relation is still commonly cited in many modern textbooks and used in modern research.
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https://en.wikipedia.org/wiki/2%2C5-Dimethoxy-4-chloroamphetamine
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2,5-Dimethoxy-4-chloroamphetamine (DOC) is a psychedelic drug of the phenethylamine and amphetamine chemical classes. It was presumably first synthesized by Alexander Shulgin, and was described in his book PiHKAL (Phenethylamines i Have Known And Loved).
Chemistry
DOC is a substituted alpha-methylated phenethylamine, a class of compounds commonly known as amphetamines. The phenethylamine equivalent (lacking the alpha-methyl group) is 2C-C. DOC has a stereocenter and (R)-(−)-DOC is the more active stereoisomer.
Pharmacology
DOC acts as a selective 5-HT2A, and 5-HT2C receptor partial agonist. Its psychedelic effects are mediated via its actions on the 5-HT2A receptor.
Dosage
A normal average dose of DOC ranges from 0.5–7.0 mg the former producing threshold effects, and the latter producing extremely strong effects. Onset of the drug is 1–3 hours, peak and plateau at 4–8 hours, and a gradual come down with residual stimulation at 9-20h. After effects can last well into the next day.
Effects
Unlike simple amphetamines, DOC is considered a chemical that influences cognitive and perception processes of the brain. The strongest supposed effects include open and closed eye visuals, increased awareness of sound and movement, and euphoria. In the autobiography PiHKAL, Alexander Shulgin included a description of DOC as "an archetypal psychedelic" (#64); its presumed full-range visual, audio, physical, and mental effects show exhilarating clarity, and some overwhelming, humbli
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https://en.wikipedia.org/wiki/Proscaline
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Proscaline (4-propoxy-3,5-dimethoxyphenethylamine or 4-propoxy-3,5-DMPEA) is a psychedelic and hallucinogenic drug. It has structural properties similar to the drugs mescaline, isoproscaline, and escaline. In PiHKAL, Alexander Shulgin reports that a dose of 30–60 mg produces effects lasting 8–12 hours.
Chemistry
Proscaline is in a class of compounds commonly known as phenethylamines, and is the 4-propoxy homolog of mescaline. The full name of the chemical is 4-propoxy-3,5-dimethoxyphenethylamine.
Legality
Proscaline is a Class A controlled substance in the UK.
Proscaline is unscheduled and unregulated in the United States, but it could be considered an analog of a schedule I drug, mescaline, under the Federal Analog Act and thus be subject to the same control measures and penalties for possession and manufacture as a Schedule I drug.
See also
Substituted phenethylamine
Allylescaline
3C-P
Mescaline
PiHKAL
References
Psychedelic phenethylamines
Designer drugs
Phenol ethers
Mescalines
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https://en.wikipedia.org/wiki/Ore%20extension
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In mathematics, especially in the area of algebra known as ring theory, an Ore extension, named after Øystein Ore, is a special type of a ring extension whose properties are relatively well understood. Elements of a Ore extension are called Ore polynomials.
Ore extensions appear in several natural contexts, including skew and differential polynomial rings, group algebras of polycyclic groups, universal enveloping algebras of solvable Lie algebras, and coordinate rings of quantum groups.
Definition
Suppose that R is a (not necessarily commutative) ring, is a ring homomorphism, and is a σ-derivation of R, which means that is a homomorphism of abelian groups satisfying
.
Then the Ore extension , also called a skew polynomial ring, is the noncommutative ring obtained by giving the ring of polynomials a new multiplication, subject to the identity
.
If δ = 0 (i.e., is the zero map) then the Ore extension is denoted R[x; σ]. If σ = 1 (i.e., the identity map) then the Ore extension is denoted R[ x, δ ] and is called a differential polynomial ring.
Examples
The Weyl algebras are Ore extensions, with R any commutative polynomial ring, σ the identity ring endomorphism, and δ the polynomial derivative. Ore algebras are a class of iterated Ore extensions under suitable constraints that permit to develop a noncommutative extension of the theory of Gröbner bases.
Properties
An Ore extension of a domain is a domain.
An Ore extension of a skew field is a non-co
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https://en.wikipedia.org/wiki/Bounds-checking%20elimination
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In computer science, bounds-checking elimination is a compiler optimization useful in programming languages or runtime systems that enforce bounds checking, the practice of checking every index into an array to verify that the index is within the defined valid range of indexes. Its goal is to detect which of these indexing operations do not need to be validated at runtime, and eliminating those checks.
One common example is accessing an array element, modifying it, and storing the modified value in the same array at the same location. Normally, this example would result in a bounds check when the element is read from the array and a second bounds check when the modified element is stored using the same array index. Bounds-checking elimination could eliminate the second check if the compiler or runtime can determine that neither the array size nor the index could change between the two array operations. Another example occurs when a programmer loops over the elements of the array, and the loop condition guarantees that the index is within the bounds of the array. It may be difficult to detect that the programmer's manual check renders the automatic check redundant. However, it may still be possible for the compiler or runtime to perform proper bounds-checking elimination in this case.
Implementations
In natively compiled languages
One technique for bounds-checking elimination is to use a typed static single assignment form representation and for each array to create a new
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https://en.wikipedia.org/wiki/Miguel%20Jos%C3%A9%20Yacam%C3%A1n
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Miguel José Yacamán (born 1946 in Córdoba, Veracruz) is a Mexican physicist who has made contributions to the fields of materials science, nanotechnology, and physics.
His research has focused on the correlation of structure and properties in nanomaterials and he has developed electron microscopy methods to study nanoparticles and 2-D materials. The present focuses of his work are to develop the nanoscale equivalent of high entropy alloys and new catalysts to produce cleaner fuels.
He earned his Ph.D. in Physics in 1972 from the National Autonomous University of Mexico and did his postdoctoral materials science studies at the University of Oxford. He was also a Postdoctoral Fellow at the NASA Ames Research Center in Mountain View, California from 1978-1979.
Yacamán became the director of the Institute of Physics from 1983-1991. He was the Reese Endowed Professor in Engineering at the University of Texas at Austin from 2001-2008. In 2008, he joined The University of Texas at San Antonio (UTSA) to chair the Department of Physics and Astronomy in the College of Sciences until 2018.
As of 2019, he is a professor of physics at Northern Arizona University.
Research
Yacamán has done research on the structure and properties of nanoparticles including metals, semiconductors, and magnetic materials. He has worked on synthesis and characterization of new materials (mainly nanoparticles), surfaces and interfaces, defects in solids, electron diffraction and imaging theory, quasicrys
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https://en.wikipedia.org/wiki/Johann%20Christian%20Ludwig%20Hellwig
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Johann Christian Ludwig Hellwig (8 November 1743, in Garz/Rügen – 10 October 1831, in Braunschweig) was a German mathematician, entomologist and wargame designer.
Biography
After studies of mathematics and natural history at the university of Frankfurt, he became, in 1766, adviser to prince Wilhelm Adolf von Braunschweig at the time of his voyage in the south of Russia.
In 1771, he was appointed teacher of mathematics and natural sciences in two colleges of Brunswick and in 1790 he was appointed to teach mathematics and natural sciences at the Collegium Carolinum in Braunschweig, becoming full professor in 1802. He taught mathematics when the College Carolinum was converted to the military academy of Braunschweig. Teaching military sciences inspired his work on wargames.
A number of his students became significant mathematicians: Conrad Diedrich Stahl, professor in Jena, then in Landshut and later in Munich, Karl Bartels, state councilor and professor in Dorpat, Brandan Mollweide in Leipzig, the astronomer AH Chr. Gelpcke in Braunschweig, Fr. Wilh. Spehr in Brunswick, Karl Graeffe in Zurich and K. Fr. Gaussin
He was the tutor and the father-in-law of the German entomologist Johann Karl Wilhelm Illiger (1775–1813), who became director of the zoological garden of Berlin, of the mineralogist Gottlieb Peter Sillem (who succeeded him at the school of Braunschweig) and the count Johann Centurius Hoffmannsegg (1766–1849). At his death he had served the state of Brunswick for 6
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https://en.wikipedia.org/wiki/Analytic%20manifold
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In mathematics, an analytic manifold, also known as a manifold, is a differentiable manifold with analytic transition maps. The term usually refers to real analytic manifolds, although complex manifolds are also analytic. In algebraic geometry, analytic spaces are a generalization of analytic manifolds such that singularities are permitted.
For , the space of analytic functions, , consists of infinitely differentiable functions , such that the Taylor series
converges to in a neighborhood of , for all . The requirement that the transition maps be analytic is significantly more restrictive than that they be infinitely differentiable; the analytic manifolds are a proper subset of the smooth, i.e. , manifolds. There are many similarities between the theory of analytic and smooth manifolds, but a critical difference is that analytic manifolds do not admit analytic partitions of unity, whereas smooth partitions of unity are an essential tool in the study of smooth manifolds. A fuller description of the definitions and general theory can be found at differentiable manifolds, for the real case, and at complex manifolds, for the complex case.
See also
Complex manifold
Analytic variety
References
Structures on manifolds
Manifolds
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