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which 900 km were developed. In the Walloon Region, they form the RAVeL network. In Flanders, there is a network of towpaths, railway trails, and other independent cycle paths. Most are integrated into the numbered-node cycle networks of the provinces, or belong to LF-routes (Dutch: lange-afstandsfietsroute, long-distance tourist cycle routes) or the bicycle highway network (Dutch: fietssnelweg, utilitarian voies vertes providing direct routes between and around cities). === Netherlands === In the Netherlands, the situation and terminology are comparable to Flanders, with the difference that there are few rail trails and many other independent cycle paths. === France === In France, a decree of 16 September 2004 introduced voies vertes into the Highway Code: voies vertes are defined as roads "exclusively reserved for the circulation of non-motorized vehicles, pedestrians and horse riders." === Switzerland === In Switzerland, there's a cross-border voie verte from Geneva to Annemasse. A voie verte through Lausanne (along the railroad tracks) is programmed for completion in 2018. == Features and Benefits == They are most often developed on old railway lines, towpaths, roads closed to automobile traffic, and cultural routes (Roman roads, pilgrimage routes). They have certain characteristics: Ease of access: their low or nonexistent slopes allow for use by all types of users, including those with reduced mobility; Safety due to their physical separation from roadways and appropriate intersection design; Continuity of routes with alternative solutions in case of obstacles; Environmental respect along the paths and encouragement for users to respect it. Voies vertes also offer services, located in preserved old facilities such as former railway stations and lockkeeper's houses. These services can be of various types: accommodation, museums, bike rental, equestrian accommodation, community centers, etc. They cater to both local users and tourists. voies vertes are provided with information (maps, brochures, etc.) about the
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route itself and nearby sites. For example, several tens of kilometers of the former coastal railway of the Chemins de Fer de Provence have been converted into a cycle path between Toulon and Pramousquier (in the municipality of Le Lavandou). This example illustrates the main criticism of voies vertes, namely the fact that they sometimes contribute to downgrading and therefore definitively condemning railway lines that could potentially be reopened for collectivization and decarbonization of travel in peri-urban or rural areas, instead of taking up space on roads. This competition between two complementary modes in an era of energy transition inducing increasing decarbonization of travel can therefore be ironic. == Photographs == == Notes and references == == See also == Aménagement cyclable === Bibliography === Bonduelle, Michel (2003). La France des voies vertes: cyclistes, rollers, randonneurs (in French) (Ouest-France ed.). Rennes. p. 141. ISBN 2-7373-3131-5.{{cite book}}: CS1 maint: location missing publisher (link) France à vélo, France des voies vertes: les clefs de la réussite (in French). Paris: ODIT France. 2006. p. 104. ISBN 2-915215-26-X. Guide de bonnes pratiques des voies vertes en Europe: exemples de réalisations urbaines et périurbaines, Association européenne des voies vertes (PDF) (in French). Bruxelles: Commission européenne, Direction générale de l'environnement. 2000. Mercat, Nicolas (2003). Voies vertes: fréquentation et impact: panorama de l'offre (in French). Paris: AFIT. p. 93. ISBN 2-910388-94-8. Guide co-rédigé par les ministères français de l'environnement, de l'équipement, des sports : «Fiche "choix techniques"», véloroutes et voies vertes (PDF). 2000. p. 90. Cahier des charges "Schéma national des véloroutes et voies vertes" (in French). Ministère de l’Aménagement du territoire et de l’environnement, Ministère de l’Équipement, des transports et du logement, Ministère de la Jeunesse et des sports; Secrétariat d’État au Tourisme. May 2001. Pistes cyclables - conception des structures. LCPC, Certu. 1986. p. 50.
|
{
"page_id": 76155969,
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"title": "Voie verte"
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Recommandations pour les aménagements cyclables. Certu. April 2000. p. 108. Fiches véloroutes et voies vertes 1 "Les relais vélo" et 2 "Traversées d'agglomération" (October and November, 2001) (in French). Paris: MEDD. Mission nationale Véloroutes et voies vertes - MN3V. Véloroutes voies vertes l'avenir est aux circulations douces (PDF) (in French).{{cite book}}: CS1 maint: numeric names: authors list (link) Réseau vert européen, actes du colloque de Lille. September 2000. Agence française de l’ingénierie touristique (Afit) (2003). Voies vertes: fréquentation et impact. Le Brethon, Brigitte (March 2004). "Propositions pour encourager le développement de la bicyclette en France". La Documentation française. === Related articles === Greenway (landscape) RAVeL network Green infrastructure Long-distance cycling route Rail trail Otago Central Rail Trail === External links === Team VéloTousTerriens Evasion Rouen Association Européenne des Voies Vertes Association Française des Véloroutes et Voies Vertes France Vélo Tourisme Carte de France des voies vertes Le portail touristique national des parcours à vélo et de voies vertes Observatoire Européen des Voies Vertes 4e Conférence européenne sur les voies vertes, Actes du colloque sur les Voies vertes urbaines et périurbaines(6,7,8 novembre 2003), Liège - Belgique
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In mathematics, the Zakharov system is a system of non-linear partial differential equations, introduced by Vladimir Zakharov in 1972 to describe the propagation of Langmuir waves in an ionized plasma. The system consists of a complex field u and a real field n satisfying the equations i ∂ t u + ∇ 2 u = u n ◻ n = − ∇ 2 ( | u | 2 ) {\displaystyle {\begin{aligned}i\partial _{t}^{}u+\nabla ^{2}u&=un\\\Box n&=-\nabla ^{2}(|u|_{}^{2})\end{aligned}}} where ◻ {\displaystyle \Box } is the d'Alembert operator. == See also == Resonant interaction; the Zakharov equation describes non-linear resonant interactions. == References == Zakharov, V. E. (1968). Stability of periodic waves of finite amplitude on the surface of a deep fluid. Journal of Applied Mechanics and Technical Physics, 9(2), 190-194. Zakharov, V. E. (1972), "Collapse of Langmuir waves", Soviet Journal of Experimental and Theoretical Physics, 35: 908–914, Bibcode:1972JETP...35..908Z.
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"page_id": 16714816,
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"title": "Zakharov system"
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Resource intensity is a measure of the resources (e.g. water, energy, materials) needed for the production, processing and disposal of a unit of good or service, or for the completion of a process or activity; it is therefore a measure of the efficiency of resource use. It is often expressed as the quantity of resource embodied in unit cost e.g. litres of water per $1 spent on product. In national economic and sustainability accounting it can be calculated as units of resource expended per unit of GDP. When applied to a single person it is expressed as the resource use of that person per unit of consumption. Relatively high resource intensities indicate a high price or environmental cost of converting resource into GDP; low resource intensity indicates a lower price or environmental cost of converting resource into GDP. Resource productivity and resource intensity are key concepts used in sustainability measurement as they measure attempts to decouple the connection between resource use and environmental degradation. Their strength is that they can be used as a metric for both economic and environmental cost. Although these concepts are two sides of the same coin, in practice they involve very different approaches and can be viewed as reflecting, on the one hand, the efficiency of resource production as outcome per unit of resource use (resource productivity) and, on the other hand, the efficiency of resource consumption as resource use per unit outcome (resource intensity). The sustainability objective is to maximize resource productivity while minimizing resource intensity. == See also == == References ==
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{
"page_id": 18484291,
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"title": "Resource intensity"
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Behind the ostium of the eustachian tube (ostium pharyngeum tuba auditiva) is a deep recess, the pharyngeal recess (fossa of Rosenmüller). == Clinical significance == At the base of this recess is the retropharyngeal lymph node (the node of Rouvière). This is clinically significant in that it may be involved in certain head and neck cancers, notably nasopharyngeal cancer. == References == This article incorporates text in the public domain from page 1141 of the 20th edition of Gray's Anatomy (1918) == External links == synd/2659 at Whonamedit? "Rosenmullers fossa". Medcyclopaedia. GE. Archived from the original on 2007-06-20.
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"page_id": 8653893,
"source": null,
"title": "Pharyngeal recess"
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An n-gram is a sequence of n adjacent symbols in particular order. The symbols may be n adjacent letters (including punctuation marks and blanks), syllables, or rarely whole words found in a language dataset; or adjacent phonemes extracted from a speech-recording dataset, or adjacent base pairs extracted from a genome. They are collected from a text corpus or speech corpus. If Latin numerical prefixes are used, then n-gram of size 1 is called a "unigram", size 2 a "bigram" (or, less commonly, a "digram") etc. If, instead of the Latin ones, the English cardinal numbers are furtherly used, then they are called "four-gram", "five-gram", etc. Similarly, using Greek numerical prefixes such as "monomer", "dimer", "trimer", "tetramer", "pentamer", etc., or English cardinal numbers, "one-mer", "two-mer", "three-mer", etc. are used in computational biology, for polymers or oligomers of a known size, called k-mers. When the items are words, n-grams may also be called shingles. In the context of natural language processing (NLP), the use of n-grams allows bag-of-words models to capture information such as word order, which would not be possible in the traditional bag of words setting. == Examples == (Shannon 1951) discussed n-gram models of English. For example: 3-gram character model (random draw based on the probabilities of each trigram): in no ist lat whey cratict froure birs grocid pondenome of demonstures of the retagin is regiactiona of cre 2-gram word model (random draw of words taking into account their transition probabilities): the head and in frontal attack on an english writer that the character of this point is therefore another method for the letters that the time of who ever told the problem for an unexpected Figure 1 shows several example sequences and the corresponding 1-gram, 2-gram and 3-gram sequences. Here are further examples; these are word-level 3-grams and
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"page_id": 986182,
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4-grams (and counts of the number of times they appeared) from the Google n-gram corpus. 3-grams ceramics collectables collectibles (55) ceramics collectables fine (130) ceramics collected by (52) ceramics collectible pottery (50) ceramics collectibles cooking (45) 4-grams serve as the incoming (92) serve as the incubator (99) serve as the independent (794) serve as the index (223) serve as the indication (72) serve as the indicator (120) == References == == Further reading == Manning, Christopher D.; Schütze, Hinrich; Foundations of Statistical Natural Language Processing, MIT Press: 1999, ISBN 0-262-13360-1 White, Owen; Dunning, Ted; Sutton, Granger; Adams, Mark; Venter, J. Craig; Fields, Chris (1993). "A quality control algorithm for dna sequencing projects". Nucleic Acids Research. 21 (16): 3829–3838. doi:10.1093/nar/21.16.3829. PMC 309901. PMID 8367301. Damerau, Frederick J.; Markov Models and Linguistic Theory, Mouton, The Hague, 1971 Figueroa, Alejandro; Atkinson, John (2012). "Contextual Language Models For Ranking Answers To Natural Language Definition Questions". Computational Intelligence. 28 (4): 528–548. doi:10.1111/j.1467-8640.2012.00426.x. S2CID 27378409. Brocardo, Marcelo Luiz; Traore, Issa; Saad, Sherif; Woungang, Isaac (2013). Authorship Verification for Short Messages Using Stylometry. IEEE International Conference on Computer, Information and Telecommunication Systems (CITS). == See also == Google Books Ngram Viewer == External links == Ngram Extractor: Gives weight of n-gram based on their frequency. Google's Google Books n-gram viewer and Web n-grams database (September 2006) STATOPERATOR N-grams Project Weighted n-gram viewer for every domain in Alexa Top 1M 1,000,000 most frequent 2,3,4,5-grams from the 425 million word Corpus of Contemporary American English Peachnote's music ngram viewer Stochastic Language Models (n-Gram) Specification (W3C) Michael Collins's notes on n-Gram Language Models OpenRefine: Clustering In Depth
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"page_id": 986182,
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3-Methyl-4-octanolide, also called β-methyl-γ-octalactone or 5-butyldihydro-4-methylfuran-2-one can be either of two chemical products of the lactone family: cis-3-Methyl-4-octanolide, or "whisky lactone", the component of oak wood that imparts flavor to whisky trans-3-Methyl-4-octanolide, also found in oak wood.
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{
"page_id": 30280773,
"source": null,
"title": "3-Methyl-4-octanolide"
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In analytic geometry, the intersection of a line and a plane in three-dimensional space can be the empty set, a point, or a line. It is the entire line if that line is embedded in the plane, and is the empty set if the line is parallel to the plane but outside it. Otherwise, the line cuts through the plane at a single point. Distinguishing these cases, and determining equations for the point and line in the latter cases, have use in computer graphics, motion planning, and collision detection. == Algebraic form == In vector notation, a plane can be expressed as the set of points p {\displaystyle \mathbf {p} } for which ( p − p 0 ) ⋅ n = 0 {\displaystyle (\mathbf {p} -\mathbf {p_{0}} )\cdot \mathbf {n} =0} where n {\displaystyle \mathbf {n} } is a normal vector to the plane and p 0 {\displaystyle \mathbf {p_{0}} } is a point on the plane. (The notation a ⋅ b {\displaystyle \mathbf {a} \cdot \mathbf {b} } denotes the dot product of the vectors a {\displaystyle \mathbf {a} } and b {\displaystyle \mathbf {b} } .) The vector equation for a line is p = l 0 + l d d ∈ R {\displaystyle \mathbf {p} =\mathbf {l_{0}} +\mathbf {l} \ d\quad d\in \mathbb {R} } where l {\displaystyle \mathbf {l} } is a unit vector in the direction of the line, l 0 {\displaystyle \mathbf {l_{0}} } is a point on the line, and d {\displaystyle d} is a scalar in the real number domain. Substituting the equation for the line into the equation for the plane gives ( ( l 0 + l d ) − p 0 ) ⋅ n = 0. {\displaystyle ((\mathbf {l_{0}} +\mathbf {l} \ d)-\mathbf {p_{0}} )\cdot \mathbf {n} =0.}
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"page_id": 3279949,
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"title": "Line–plane intersection"
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Expanding gives ( l ⋅ n ) d + ( l 0 − p 0 ) ⋅ n = 0. {\displaystyle (\mathbf {l} \cdot \mathbf {n} )\ d+(\mathbf {l_{0}} -\mathbf {p_{0}} )\cdot \mathbf {n} =0.} And solving for d {\displaystyle d} gives d = ( p 0 − l 0 ) ⋅ n l ⋅ n . {\displaystyle d={(\mathbf {p_{0}} -\mathbf {l_{0}} )\cdot \mathbf {n} \over \mathbf {l} \cdot \mathbf {n} }.} If l ⋅ n = 0 {\displaystyle \mathbf {l} \cdot \mathbf {n} =0} then the line and plane are parallel. There will be two cases: if ( p 0 − l 0 ) ⋅ n = 0 {\displaystyle (\mathbf {p_{0}} -\mathbf {l_{0}} )\cdot \mathbf {n} =0} then the line is contained in the plane, that is, the line intersects the plane at each point of the line. Otherwise, the line and plane have no intersection. If l ⋅ n ≠ 0 {\displaystyle \mathbf {l} \cdot \mathbf {n} \neq 0} there is a single point of intersection. The value of d {\displaystyle d} can be calculated and the point of intersection, p {\displaystyle \mathbf {p} } , is given by p = l 0 + l d {\displaystyle \mathbf {p} =\mathbf {l_{0}} +\mathbf {l} \ d} . == Parametric form == A line is described by all points that are a given direction from a point. A general point on a line passing through points l a = ( x a , y a , z a ) {\displaystyle \mathbf {l} _{a}=(x_{a},y_{a},z_{a})} and l b = ( x b , y b , z b ) {\displaystyle \mathbf {l} _{b}=(x_{b},y_{b},z_{b})} can be represented as l a + l a b t , t ∈ R , {\displaystyle \mathbf {l} _{a}+\mathbf {l} _{ab}t,\quad t\in \mathbb {R} ,} where l a
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"page_id": 3279949,
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"title": "Line–plane intersection"
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b = l b − l a {\displaystyle \mathbf {l} _{ab}=\mathbf {l} _{b}-\mathbf {l} _{a}} is the vector pointing from l a {\displaystyle \mathbf {l} _{a}} to l b {\displaystyle \mathbf {l} _{b}} . Similarly a general point on a plane determined by the triangle defined by the points p 0 = ( x 0 , y 0 , z 0 ) {\displaystyle \mathbf {p} _{0}=(x_{0},y_{0},z_{0})} , p 1 = ( x 1 , y 1 , z 1 ) {\displaystyle \mathbf {p} _{1}=(x_{1},y_{1},z_{1})} and p 2 = ( x 2 , y 2 , z 2 ) {\displaystyle \mathbf {p} _{2}=(x_{2},y_{2},z_{2})} can be represented as p 0 + p 01 u + p 02 v , u , v ∈ R , {\displaystyle \mathbf {p} _{0}+\mathbf {p} _{01}u+\mathbf {p} _{02}v,\quad u,v\in \mathbb {R} ,} where p 01 = p 1 − p 0 {\displaystyle \mathbf {p} _{01}=\mathbf {p} _{1}-\mathbf {p} _{0}} is the vector pointing from p 0 {\displaystyle \mathbf {p} _{0}} to p 1 {\displaystyle \mathbf {p} _{1}} , and p 02 = p 2 − p 0 {\displaystyle \mathbf {p} _{02}=\mathbf {p} _{2}-\mathbf {p} _{0}} is the vector pointing from p 0 {\displaystyle \mathbf {p} _{0}} to p 2 {\displaystyle \mathbf {p} _{2}} . The point at which the line intersects the plane is therefore described by setting the point on the line equal to the point on the plane, giving the parametric equation: l a + l a b t = p 0 + p 01 u + p 02 v . {\displaystyle \mathbf {l} _{a}+\mathbf {l} _{ab}t=\mathbf {p} _{0}+\mathbf {p} _{01}u+\mathbf {p} _{02}v.} This can be rewritten as l a − p 0 = − l a b t + p 01 u + p 02 v , {\displaystyle \mathbf {l} _{a}-\mathbf {p} _{0}=-\mathbf {l}
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{
"page_id": 3279949,
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"title": "Line–plane intersection"
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_{ab}t+\mathbf {p} _{01}u+\mathbf {p} _{02}v,} which can be expressed in matrix form as [ l a − p 0 ] = [ − l a b p 01 p 02 ] [ t u v ] , {\displaystyle {\begin{bmatrix}\mathbf {l} _{a}-\mathbf {p} _{0}\end{bmatrix}}={\begin{bmatrix}-\mathbf {l} _{ab}&\mathbf {p} _{01}&\mathbf {p} _{02}\end{bmatrix}}{\begin{bmatrix}t\\u\\v\end{bmatrix}},} where the vectors are written as column vectors. This produces a system of linear equations which can be solved for t {\displaystyle t} , u {\displaystyle u} and v {\displaystyle v} . If the solution satisfies the condition t ∈ [ 0 , 1 ] , {\displaystyle t\in [0,1],} , then the intersection point is on the line segment between l a {\displaystyle \mathbf {l} _{a}} and l b {\displaystyle \mathbf {l} _{b}} , otherwise it is elsewhere on the line. Likewise, if the solution satisfies u , v ∈ [ 0 , 1 ] , {\displaystyle u,v\in [0,1],} , then the intersection point is in the parallelogram formed by the point p 0 {\displaystyle \mathbf {p} _{0}} and vectors p 01 {\displaystyle \mathbf {p} _{01}} and p 02 {\displaystyle \mathbf {p} _{02}} . If the solution additionally satisfies ( u + v ) ≤ 1 {\displaystyle (u+v)\leq 1} , then the intersection point lies in the triangle formed by the three points p 0 {\displaystyle \mathbf {p} _{0}} , p 1 {\displaystyle \mathbf {p} _{1}} and p 2 {\displaystyle \mathbf {p} _{2}} . The determinant of the matrix can be calculated as det ( [ − l a b p 01 p 02 ] ) = − l a b ⋅ ( p 01 × p 02 ) . {\displaystyle \det({\begin{bmatrix}-\mathbf {l} _{ab}&\mathbf {p} _{01}&\mathbf {p} _{02}\end{bmatrix}})=-\mathbf {l} _{ab}\cdot (\mathbf {p} _{01}\times \mathbf {p} _{02}).} If the determinant is zero, then there is no unique solution; the line is either
|
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"page_id": 3279949,
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in the plane or parallel to it. If a unique solution exists (determinant is not 0), then it can be found by inverting the matrix and rearranging: [ t u v ] = [ − l a b p 01 p 02 ] − 1 [ l a − p 0 ] , {\displaystyle {\begin{bmatrix}t\\u\\v\end{bmatrix}}={\begin{bmatrix}-\mathbf {l} _{ab}&\mathbf {p} _{01}&\mathbf {p} _{02}\end{bmatrix}}^{-1}{\begin{bmatrix}\mathbf {l} _{a}-\mathbf {p} _{0}\end{bmatrix}},} which expands to [ t u v ] = 1 − l a b ⋅ ( p 01 × p 02 ) [ ( p 01 × p 02 ) T ( p 02 × − l a b ) T ( − l a b × p 01 ) T ] [ l a − p 0 ] {\displaystyle {\begin{bmatrix}t\\u\\v\end{bmatrix}}={\frac {1}{-\mathbf {l} _{ab}\cdot (\mathbf {p} _{01}\times \mathbf {p} _{02})}}{\begin{bmatrix}{(\mathbf {p} _{01}\times \mathbf {p} _{02})}^{\mathrm {T} }\\{(\mathbf {p} _{02}\times -\mathbf {l} _{ab})}^{\mathrm {T} }\\{(-\mathbf {l} _{ab}\times \mathbf {p} _{01})}^{\mathrm {T} }\end{bmatrix}}{\begin{bmatrix}\mathbf {l} _{a}-\mathbf {p} _{0}\end{bmatrix}}} and then to [ t u v ] = 1 − l a b ⋅ ( p 01 × p 02 ) [ ( p 01 × p 02 ) ⋅ ( l a − p 0 ) ( p 02 × − l a b ) ⋅ ( l a − p 0 ) ( − l a b × p 01 ) ⋅ ( l a − p 0 ) ] , {\displaystyle {\begin{bmatrix}t\\u\\v\end{bmatrix}}={\frac {1}{-\mathbf {l} _{ab}\cdot (\mathbf {p} _{01}\times \mathbf {p} _{02})}}{\begin{bmatrix}{(\mathbf {p} _{01}\times \mathbf {p} _{02})}\cdot (\mathbf {l} _{a}-\mathbf {p} _{0})\\{(\mathbf {p} _{02}\times -\mathbf {l} _{ab})}\cdot (\mathbf {l} _{a}-\mathbf {p} _{0})\\{(-\mathbf {l} _{ab}\times \mathbf {p} _{01})}\cdot (\mathbf {l} _{a}-\mathbf {p} _{0})\end{bmatrix}},} thus giving the solutions: t = ( p 01 × p 02 ) ⋅ ( l a − p 0 ) − l a b
|
{
"page_id": 3279949,
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"title": "Line–plane intersection"
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⋅ ( p 01 × p 02 ) {\displaystyle t={\frac {{(\mathbf {p} _{01}\times \mathbf {p} _{02})}\cdot (\mathbf {l} _{a}-\mathbf {p} _{0})}{-\mathbf {l} _{ab}\cdot (\mathbf {p} _{01}\times \mathbf {p} _{02})}}} u = ( p 02 × − l a b ) ⋅ ( l a − p 0 ) − l a b ⋅ ( p 01 × p 02 ) {\displaystyle u={\frac {{(\mathbf {p} _{02}\times -\mathbf {l} _{ab})}\cdot (\mathbf {l} _{a}-\mathbf {p} _{0})}{-\mathbf {l} _{ab}\cdot (\mathbf {p} _{01}\times \mathbf {p} _{02})}}} v = ( − l a b × p 01 ) ⋅ ( l a − p 0 ) − l a b ⋅ ( p 01 × p 02 ) . {\displaystyle v={\frac {{(-\mathbf {l} _{ab}\times \mathbf {p} _{01})}\cdot (\mathbf {l} _{a}-\mathbf {p} _{0})}{-\mathbf {l} _{ab}\cdot (\mathbf {p} _{01}\times \mathbf {p} _{02})}}.} The point of intersection is then equal to l a + l a b t {\displaystyle \mathbf {l} _{a}+\mathbf {l} _{ab}t} == Uses == In the ray tracing method of computer graphics a surface can be represented as a set of pieces of planes. The intersection of a ray of light with each plane is used to produce an image of the surface. In vision-based 3D reconstruction, a subfield of computer vision, depth values are commonly measured by so-called triangulation method, which finds the intersection between light plane and ray reflected toward camera. The algorithm can be generalised to cover intersection with other planar figures, in particular, the intersection of a polyhedron with a line. == See also == Plücker coordinates#Plane-line meet calculating the intersection when the line is expressed by Plücker coordinates. Plane–plane intersection == References == Intersection of a Line and a Plane
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Centro di Cultura e Civiltà Contadina - Biblioteca Internazionale La Vigna is an institute of documentation specialised in studies concerning agriculture and wine. It is considered as the most important reference point for ampelographic research worldwide. It is situated in Vicenza in Contrà Porta Santa Croce n. 3 in Palazzo Brusarosco, then Galla. The palace is an eighteenth-century building, which was partially restored by the architect Carlo Scarpa. == History of the institution == “Centro di Cultura e Civiltà Contadina” - Biblioteca Internazionale “La Vigna” was established by Demetrio Zaccaria. He was an entrepreneur from Vicenza who began to get interested in the field after having read a book about oenology in New York City in 1951. It took twenty years to build an international library for researchers and connoisseurs. Dictionary of Wine by Frank Schoonmaker was the first book that was bought. Demetrio Zaccaria took part in international meetings, maintained important connections worldwide and started to buy ancient and rare books. Particularly important was the meeting with André Simon in London. André Simon, who was the founder of the International Wine and Food Society, author of important books about gastronomy and wine, as well as a leading figure in the Champagne commerce worldwide, became a model to follow for Demetrio Zaccaria. In the early seventies Zaccaria left Toscolano, on the Lake Garda, where he had lived since 1958, and moved permanently to Vicenza with his collection of books. In 1980 he bought Palazzo Brusarosco which is the base of the present library. The following year, when he was seventy, he donated the palace and his collection of almost 10.000 books to the “Comune di Vicenza”. He did this because he was worried about the future of his collection and also because he tried in vain to find another settlement.
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"page_id": 33557584,
"source": null,
"title": "International Library La Vigna"
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He became general secretary of “Centro di Cultura e Civiltà Contadina” and of the International Library “La Vigna”. Demetrio Zaccaria died in 1993 after having received important international recognitions. == The base == “Centro di Cultura e Civiltà Contadina” and Biblioteca Internazionale “La Vigna” have their headquarters in Palazzo Brusarosco. The few information about the original building say that it was a house situated within the fifteenth-century Scaliger city walls. In the following centuries the house was time after time modified. In the eighteenth century the building was widened by Ottone Calderari. The new owner Orazio Brusarosco entrusted the architect Tommaso Becega the task of rebuilding the porch and facade in 1833. During the Second World War the building was hardly damaged because of the Anglo-American bombings. The lawyer from Vicenza Ettore Gallo bought the building in the early seventies. He assigned the renovations to the architect Carlo Scarpa. Then, he moved there his law firm and his house. On the second floor Scarpa planned the house for the family Gallo, converting the loft into a large flat. There he converged two themes he loved: the residence and the museum. The special features of the flat are fluent paths, smooth corners and the absence of doors. It is also lighted from natural, indirect and diaphanous light. Today this flat is mainly used for exhibitions and conferences. On the first floor, where the present library is based, Scarpa strengthened the ceiling of the living room and of the hall inserting girders. On the ground floor was built an independent flat that is now used as storage area of books. == Collections == The current book collection is made of about 50.000 works, especially concerning agriculture, vineyard-growing, wine production, beekeeping, the production of olive oil and of honey and gastronomy treatises. The
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"page_id": 33557584,
"source": null,
"title": "International Library La Vigna"
}
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collection is constantly updated with new purchases, both of ancient and modern volumes. The ancient collection includes the most important editions of gastronomy that were published in Italy between the sixteenth and the seventeenth century. A peculiar example is De honesta voluptate by Platina (1530), which is considered as the first treatise of modern gastronomy. As regards the works about enology, the library keeps some editions of De naturali vinorum historia (1596) by the Roman doctor Andrea Bacci. The physical-philological-historic-medical-chemical treatise Ampelographia (1660) by the German doctor Philipp Jacob Sachs starts the collection of treatises about ampelography which make the library an international reference point in the field. The dithyrambic literature and poetry is an important part of the initial collection. The library holds 63 of the 82 known editions of Il Bacco in Toscana by Francesco Redi. Other collections, in addition to the original collection, have increased the patrimony of the library thanks to new purchases, both of ancient and modern volumes. The most important collections are: IRA Collection (Ispettorato Regionale per l’Agricoltura): it is the library of Comizi agrari-Dipartimento di Vicenza and successively of the Itinerant Chair of the province of Vicenza. This collection has been given by the Ispettorato Regionale dell'Agricoltura. It contains 2500 works that were printed between the end of the nineteenth and the beginning of the twentieth century. The works of this collection contain information about the story of the agrarian economy in Vicenza and in Veneto in the nineteenth and twentieth century. Fagiani Collection: this collection was given as a gift by Fernando Fagiani, a historian of the economic and social thought of the nineteenth and twentieth century. It is made up of 1100 books. These books deal with the agricultural history and economy not only in Italy, but also in Europe in
|
{
"page_id": 33557584,
"source": null,
"title": "International Library La Vigna"
}
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the last centuries. Caproni Collection: the collection was bought by the heirs of Federico Caproni in 1997, who founded the Aeronautic Caproni Industries with his brother Gianni. It contains about 6500 volumes about the agricultural management and reclaims in the autarchic period. It is also made up of rare works about agricultural history: one important example is Della agricoltura by Rutilio Tauro Palladio which was published in Venice in 1528. Collection Galla: this collection was given as a gift by the lawyer Mariano Galla in 2007. It is made up of about 400 works – volumes and periodicals- about hunting that were published between the twentieth and the twenty-first century. You can find many books which describe the capture techniques of the game. There are hunting tales and diaries, precious illustrated books on birds (in particular on woodcocks), some manuals telling what to do to obtain the hunting licence and several encyclopedias. Del modo di piantare e custodire una ragnaja e di uccellare a ragna (1790) is the oldest work of the collection. This work was wrongly attributed to Bernardo Davanzati and was often published in his Opera Omnia. In reality this book was by G.A. Popoleschi, wo carefully described how to build and use this bird trap, which was probably invented in Florence in Tuscany. == Cultural initiatives == In his notarial deed, Demetrio Zaccaria wanted the denomination “Centro di Cultura e Civiltà Contadina” to be used before “Biblioteca Internazionale “La Vigna”. This aimed to promote the initiatives of researchers and enthusiasts which increase the value of the collection of the library. The specific cultural activities, whose projects have been even more elaborate and qualified, are planned and carried out thanks to the contribution of “Consiglio Scientifico”, in collaboration with hosted or external associations as “CRA”, “ Centro di
|
{
"page_id": 33557584,
"source": null,
"title": "International Library La Vigna"
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Ricerca per la Viticoltura di Conegliano”, “ Istituto di Genetica e Sperimentazione Agraria “N. Strampelli”” of Lonigo, “ Fondazione Masi”, “AIS Veneto” (Associazione Italiana Sommeliers), local consortiums for the conservation of DOC wines, “FAI”, “Club Lions”, Rotarys from Vicenza, “Associazione Italiana Cultura del Tè”, “Confraternita della Vite e del Vino del Veneto Orientale e del Friuli-Venezia Giulia” and so on. This cultural centre has also started the initiative “Amici de La Vigna” in order to support its cultural and institutional activities. == Hosted associations == The institution hosts the following associations which are engaged upon gastronomic culture and environmental conservation: Accademia internazionale “La donna e il vino” Associazione “Amici dei Parchi” Accademia italiana “La vite e il vino” Accademia italiana della cucina – Sezione di Vicenza Gruppo micologico Bresadola – Vicenza Convivium Slow Food del Vicentino == See also == == References == == External links == Official website
|
{
"page_id": 33557584,
"source": null,
"title": "International Library La Vigna"
}
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The Mid-Atlantic Ridge Ecosystem Project MAR-ECO is an international research project in which scientists from 16 nations take part. Norway, represented by the Institute of Marine Research and the University of Bergen, co-ordinates the project which will enhance our understanding of occurrence, distribution and ecology of animals and animal communities along the Mid-Atlantic Ridge between Iceland and the Azores. The Mid-Atlantic Ridge is the volcanic mountain range in the middle of the ocean, marking the spreading zone between the Eurasian and American continental plates. New ocean floor is constantly being formed, and Iceland and the Azores are volcanic islands created when the mid-ocean ridge breaks the sea surface. The groups of animals to be studied are fishes, crustaceans, cephalopods (squids) and a wide range of gelatinous animals (e.g. jellyfish) living either near the seabed or in midwater above the ridge. The research programme Census of Marine Life seriously addresses this situation and challenges marine biologists to utilize the most advanced technology to achieve true new information in areas of the ocean that were poorly studied previously. The project MAR-ECO, an element of the Census of Marine Life, rises to the challenge and investigates the diverse animal life along the vast underwater mountain chains of the open ocean. == History == MAR-ECO adopts the most advanced technology and instruments for observing and sample the animals and to tackle the challenge of working to 3500 m depth and in rugged terrain. An international multidisciplinary team of biologists, oceanographers, and engineers is offered this rare opportunity. A number of countries have committed their best research vessels, and in the 2003-2005 and 2007-2010 field phases a number of research cruise were conducted. In 2004, a two-month major international expedition was carried out by the new Norwegian vessel RV G.O. Sars, but vessels from Iceland,
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{
"page_id": 22023250,
"source": null,
"title": "Mid-Atlantic Ridge Ecosystem Project"
}
|
Russia, Germany, the United Kingdom, USA, and Portugal have also made major contributions. In June 2003 a Russian-US cruise using the crewed submersibles MIR-1 and -2 took scientists to areas never before visited by humans at 4500m below the surface. Contributing to sustainable development MAR-ECO shall enhance the basic knowledge of ocean life and thereby contribute to a sustainable international management of marine resources and the priceless biodiversity of the marine environment. Knowledge obtained by a unified international effort carries greater weight in the policy-making processes than information gathered by isolated national research. Good science may hopefully lead to international consensus on appropriate action. MAR-ECO and the Census of Marine Life emphasises public outreach and even in the planning phase MAR-ECO has enjoyed considerable public attention and support. Expeditions to unknown depths of the oceans appear to have great appeal, both to scientists and the interested laymen of all ages. === Management === The MAR-ECO management consists of a Norwegian secretariat, a public outreach group, and an international steering group. The co-ordinating institutions are Institute of Marine Research and the University of Bergen in Norway. Members of the international steering group are experienced scientists from key institutions in Norway, Iceland, Portugal (Azores), France, Germany, United Kingdom, USA, Russia and Brazil. Chair: Odd Aksel Bergstad, Norway. The project consists of 10 integrated science components dealing with different key objectives, each with dedicated teams and principal investigators. In addition, a range of education and outreach components facilitates dissemination of results to a wide audience. Common critical tasks are funded by A.P.Sloan Foundation (USA), and national sources. ==== Public Outreach Group and associates ==== The Public Outreach Group is based in Bergen, Norway, but has associates among project participants in other countries. The group works closely with the Education and Outreach team of
|
{
"page_id": 22023250,
"source": null,
"title": "Mid-Atlantic Ridge Ecosystem Project"
}
|
the Census of Marine Life based in the USA. == Backgrounders == The Mar-ECO project presented an exhibit in the Sant Ocean Hall of the Smithsonian Museum of Natural History in Washington, DC in 2010. The exhibit featured specimens, photography, art, models, and multimedia about the discoveries of the program. == References == == External links == MAR-ECOWebsite international steering group Odd Aksel Bergstad, Norway. 10 integrated science components Sponsors MAR-ECO Exhibit Institute of Marine Research University of Bergen, Bergen Museum, Norway Public Outreach Group Department of Biology ,University of Bergen, Norway. Department of Information Science and Media Studies, University of Bergen, Norway
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{
"page_id": 22023250,
"source": null,
"title": "Mid-Atlantic Ridge Ecosystem Project"
}
|
In nucleotide sugar metabolism a group of biochemicals known as nucleotide sugars act as donors for sugar residues in the glycosylation reactions that produce polysaccharides. They are substrates for glycosyltransferases. The nucleotide sugars are also intermediates in nucleotide sugar interconversions that produce some of the activated sugars needed for glycosylation reactions. Since most glycosylation takes place in the endoplasmic reticulum and golgi apparatus, there are a large family of nucleotide sugar transporters that allow nucleotide sugars to move from the cytoplasm, where they are produced, into the organelles where they are consumed. Nucleotide sugar metabolism is particularly well-studied in yeast, fungal pathogens, and bacterial pathogens, such as E. coli and Mycobacterium tuberculosis, since these molecules are required for the synthesis of glycoconjugates on the surfaces of these organisms. These glycoconjugates are virulence factors and components of the fungal and bacterial cell wall. These pathways are also studied in plants, but here the enzymes involved are less well understood. == References ==
|
{
"page_id": 14355539,
"source": null,
"title": "Nucleotide sugars metabolism"
}
|
The molecular formula C14H21NOS may refer to: Esproquin Prosulfocarb
|
{
"page_id": 77597780,
"source": null,
"title": "C14H21NOS"
}
|
Tetraterpenes are terpenes consisting of eight isoprene units and have the molecular formula C40H64. Tetraterpenoids (including many carotenoids) are tetraterpenes that have been chemically modified, as indicated by the presence of oxygen-containing functional groups. Phytoene is biosynthesized via the head-to-head condensation of two GGPP molecules. One group of tetraterpenes, and possibly the most studied one, is the carotenoids pigments. Carotenoids have important biological functions, with roles in light capture, antioxidative activity and protection against free radicals, synthesis of plant hormones and as structural components of the membranes. Aside their biological relevance, carotenoids are also high-value compounds for the food and pharmaceutical industries. Carotenoids are biosynthesized by photosynthetic and non-photosynthetic organisms; however, in photosynthetic organisms, they are essential components as accessory pigments for the light-harvesting reaction centers. Xanthophylls are another group of tetraterpene pigments distributed widely in nature. == References ==
|
{
"page_id": 5901398,
"source": null,
"title": "Tetraterpene"
}
|
In condensed matter physics, Lindhard theory is a method of calculating the effects of electric field screening by electrons in a solid. It is based on quantum mechanics (first-order perturbation theory) and the random phase approximation. It is named after Danish physicist Jens Lindhard, who first developed the theory in 1954. Thomas–Fermi screening and the plasma oscillations can be derived as a special case of the more general Lindhard formula. In particular, Thomas–Fermi screening is the limit of the Lindhard formula when the wavevector (the reciprocal of the length-scale of interest) is much smaller than the Fermi wavevector, i.e. the long-distance limit. The Lorentz–Drude expression for the plasma oscillations are recovered in the dynamic case (long wavelengths, finite frequency). This article uses cgs-Gaussian units. == Formula == The Lindhard formula for the longitudinal dielectric function is given by Here, δ {\displaystyle \delta } is a positive infinitesimal constant, V q {\displaystyle V_{\mathbf {q} }} is V eff ( q ) − V ind ( q ) {\displaystyle V_{\text{eff}}(\mathbf {q} )-V_{\text{ind}}(\mathbf {q} )} and f k {\displaystyle f_{\mathbf {k} }} is the carrier distribution function which is the Fermi–Dirac distribution function for electrons in thermodynamic equilibrium. However this Lindhard formula is valid also for nonequilibrium distribution functions. It can be obtained by first-order perturbation theory and the random phase approximation (RPA). == Limiting cases == To understand the Lindhard formula, consider some limiting cases in 2 and 3 dimensions. The 1-dimensional case is also considered in other ways. === Long wavelength limit === In the long wavelength limit ( q → 0 {\displaystyle \mathbf {q} \to 0} ), Lindhard function reduces to ϵ ( q = 0 , ω ) ≈ 1 − ω p l 2 ω 2 , {\displaystyle \epsilon (\mathbf {q} =0,\omega )\approx 1-{\frac {\omega _{\rm {pl}}^{2}}{\omega ^{2}}},}
|
{
"page_id": 22613078,
"source": null,
"title": "Lindhard theory"
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|
where ω p l 2 = 4 π e 2 N L 3 m {\displaystyle \omega _{\rm {pl}}^{2}={\frac {4\pi e^{2}N}{L^{3}m}}} is the three-dimensional plasma frequency (in SI units, replace the factor 4 π {\displaystyle 4\pi } by 1 / ϵ 0 {\displaystyle 1/\epsilon _{0}} .) For two-dimensional systems, ω p l 2 ( q ) = 2 π e 2 n q ϵ m {\displaystyle \omega _{\rm {pl}}^{2}(\mathbf {q} )={\frac {2\pi e^{2}nq}{\epsilon m}}} . This result recovers the plasma oscillations from the classical dielectric function from Drude model and from quantum mechanical free electron model. === Static limit === Consider the static limit ( ω + i δ → 0 {\displaystyle \omega +i\delta \to 0} ). The Lindhard formula becomes ϵ ( q , ω = 0 ) = 1 − V q ∑ k f k − q − f k E k − q − E k {\displaystyle \epsilon (\mathbf {q} ,\omega =0)=1-V_{\mathbf {q} }\sum _{\mathbf {k} }{\frac {f_{\mathbf {k} -\mathbf {q} }-f_{\mathbf {k} }}{E_{\mathbf {k} -\mathbf {q} }-E_{\mathbf {k} }}}} . Inserting the above equalities for the denominator and numerator, we obtain ϵ ( q , 0 ) = 1 − V q ∑ k , i − q i ∂ f ∂ k i − ℏ 2 k ⋅ q m = 1 − V q ∑ k , i q i ∂ f ∂ k i ℏ 2 k ⋅ q m {\displaystyle \epsilon (\mathbf {q} ,0)=1-V_{\mathbf {q} }\sum _{\mathbf {k} ,i}{\frac {-q_{i}{\frac {\partial f}{\partial k_{i}}}}{-{\frac {\hbar ^{2}\mathbf {k} \cdot \mathbf {q} }{m}}}}=1-V_{\mathbf {q} }\sum _{\mathbf {k} ,i}{\frac {q_{i}{\frac {\partial f}{\partial k_{i}}}}{\frac {\hbar ^{2}\mathbf {k} \cdot \mathbf {q} }{m}}}} . Assuming a thermal equilibrium Fermi–Dirac carrier distribution, we get ∑ i q i ∂ f k ∂ k i = − ∑ i q i
|
{
"page_id": 22613078,
"source": null,
"title": "Lindhard theory"
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|
∂ f k ∂ μ ∂ E k ∂ k i = − ∑ i q i k i ℏ 2 m ∂ f k ∂ μ {\displaystyle \sum _{i}{q_{i}{\frac {\partial f_{\mathbf {k} }}{\partial k_{i}}}}=-\sum _{i}{q_{i}{\frac {\partial f_{\mathbf {k} }}{\partial \mu }}{\frac {\partial E_{\mathbf {k} }}{\partial k_{i}}}}=-\sum _{i}{q_{i}k_{i}{\frac {\hbar ^{2}}{m}}{\frac {\partial f_{\mathbf {k} }}{\partial \mu }}}} here, we used E k = ℏ 2 k 2 2 m {\displaystyle E_{\mathbf {k} }={\frac {\hbar ^{2}k^{2}}{2m}}} and ∂ E k ∂ k i = ℏ 2 k i m {\displaystyle {\frac {\partial E_{\mathbf {k} }}{\partial k_{i}}}={\frac {\hbar ^{2}k_{i}}{m}}} . Therefore, ϵ ( q , 0 ) = 1 + V q ∑ k , i q i k i ℏ 2 m ∂ f k ∂ μ ℏ 2 k ⋅ q m = 1 + V q ∑ k ∂ f k ∂ μ = 1 + 4 π e 2 ϵ q 2 ∂ ∂ μ 1 L 3 ∑ k f k = 1 + 4 π e 2 ϵ q 2 ∂ ∂ μ N L 3 = 1 + 4 π e 2 ϵ q 2 ∂ n ∂ μ ≡ 1 + κ 2 q 2 . {\displaystyle {\begin{alignedat}{2}\epsilon (\mathbf {q} ,0)&=1+V_{\mathbf {q} }\sum _{\mathbf {k} ,i}{\frac {q_{i}k_{i}{\frac {\hbar ^{2}}{m}}{\frac {\partial f_{\mathbf {k} }}{\partial \mu }}}{\frac {\hbar ^{2}\mathbf {k} \cdot \mathbf {q} }{m}}}=1+V_{\mathbf {q} }\sum _{\mathbf {k} }{\frac {\partial f_{\mathbf {k} }}{\partial \mu }}=1+{\frac {4\pi e^{2}}{\epsilon q^{2}}}{\frac {\partial }{\partial \mu }}{\frac {1}{L^{3}}}\sum _{\mathbf {k} }{f_{\mathbf {k} }}\\&=1+{\frac {4\pi e^{2}}{\epsilon q^{2}}}{\frac {\partial }{\partial \mu }}{\frac {N}{L^{3}}}=1+{\frac {4\pi e^{2}}{\epsilon q^{2}}}{\frac {\partial n}{\partial \mu }}\equiv 1+{\frac {\kappa ^{2}}{q^{2}}}.\end{alignedat}}} Here, κ {\displaystyle \kappa } is the 3D screening wave number (3D inverse screening length) defined as κ = 4 π e 2 ϵ ∂ n ∂ μ {\displaystyle \kappa ={\sqrt
|
{
"page_id": 22613078,
"source": null,
"title": "Lindhard theory"
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|
{{\frac {4\pi e^{2}}{\epsilon }}{\frac {\partial n}{\partial \mu }}}}} .Then, the 3D statically screened Coulomb potential is given by V s ( q , ω = 0 ) ≡ V q ϵ ( q , 0 ) = 4 π e 2 ϵ q 2 L 3 q 2 + κ 2 q 2 = 4 π e 2 ϵ L 3 1 q 2 + κ 2 {\displaystyle V_{\rm {s}}(\mathbf {q} ,\omega =0)\equiv {\frac {V_{\mathbf {q} }}{\epsilon (\mathbf {q} ,0)}}={\frac {\frac {4\pi e^{2}}{\epsilon q^{2}L^{3}}}{\frac {q^{2}+\kappa ^{2}}{q^{2}}}}={\frac {4\pi e^{2}}{\epsilon L^{3}}}{\frac {1}{q^{2}+\kappa ^{2}}}} . And the inverse Fourier transformation of this result gives V s ( r ) = ∑ q 4 π e 2 L 3 ( q 2 + κ 2 ) e i q ⋅ r = e 2 r e − κ r {\displaystyle V_{\rm {s}}(r)=\sum _{\mathbf {q} }{{\frac {4\pi e^{2}}{L^{3}(q^{2}+\kappa ^{2})}}e^{i\mathbf {q} \cdot \mathbf {r} }}={\frac {e^{2}}{r}}e^{-\kappa r}} known as the Yukawa potential. Note that in this Fourier transformation, which is basically a sum over all q {\displaystyle \mathbf {q} } , we used the expression for small | q | {\displaystyle |\mathbf {q} |} for every value of q {\displaystyle \mathbf {q} } which is not correct. For a degenerated Fermi gas (T=0), the Fermi energy is given by E F = ℏ 2 2 m ( 3 π 2 n ) 2 3 {\displaystyle E_{\rm {F}}={\frac {\hbar ^{2}}{2m}}(3\pi ^{2}n)^{\frac {2}{3}}} , So the density is n = 1 3 π 2 ( 2 m ℏ 2 E F ) 3 2 {\displaystyle n={\frac {1}{3\pi ^{2}}}\left({\frac {2m}{\hbar ^{2}}}E_{\rm {F}}\right)^{\frac {3}{2}}} . At T=0, E F ≡ μ {\displaystyle E_{\rm {F}}\equiv \mu } , so ∂ n ∂ μ = 3 2 n E F {\displaystyle {\frac {\partial n}{\partial \mu }}={\frac {3}{2}}{\frac {n}{E_{\rm {F}}}}} . Inserting this
|
{
"page_id": 22613078,
"source": null,
"title": "Lindhard theory"
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|
into the above 3D screening wave number equation, we obtain This result recovers the 3D wave number from Thomas–Fermi screening. For reference, Debye–Hückel screening describes the non-degenerate limit case. The result is κ = 4 π e 2 n β ϵ {\displaystyle \kappa ={\sqrt {\frac {4\pi e^{2}n\beta }{\epsilon }}}} , known as the 3D Debye–Hückel screening wave number. In two dimensions, the screening wave number is Note that this result is independent of n. == Experiments on one dimensional systems == This time, consider some generalized case for lowering the dimension. The lower the dimension is, the weaker the screening effect. In lower dimension, some of the field lines pass through the barrier material wherein the screening has no effect. For the 1-dimensional case, we can guess that the screening affects only the field lines which are very close to the wire axis. In real experiment, we should also take the 3D bulk screening effect into account even though we deal with 1D case like the single filament. The Thomas–Fermi screening has been applied to an electron gas confined to a filament and a coaxial cylinder. For a K2Pt(CN)4Cl0.32·2.6H20 filament, it was found that the potential within the region between the filament and cylinder varies as e − k e f f r / r {\displaystyle e^{-k_{\rm {eff}}r}/r} and its effective screening length is about 10 times that of metallic platinum. == See also == Kohn anomaly Pomeranchuk instability Friedel oscillations == References == === General === Haug, Hartmut; W. Koch, Stephan (2004). Quantum Theory of the Optical and Electronic Properties of Semiconductors (4th ed.). World Scientific Publishing Co. Pte. Ltd. ISBN 978-981-238-609-0.
|
{
"page_id": 22613078,
"source": null,
"title": "Lindhard theory"
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== External links == Exocrine pancreas cell entry in the public domain NCI Dictionary of Cancer Terms This article incorporates public domain material from Dictionary of Cancer Terms. U.S. National Cancer Institute.
|
{
"page_id": 16256089,
"source": null,
"title": "Exocrine pancreas cell"
}
|
Herman Samuel Bloch (June 15, 1912 – June 16, 1990) was an American chemist and an inventor. Bloch invented the catalytic converter, a device that removes pollutants from automobile exhaust fumes. Bloch held more than 270 patents. He was the deputy director of research of the aerospace company AlliedSignal Inc, and chairman of the Cook County Housing Authority. He received the Chemical Pioneer Award in 1989 from the American Institute of Chemists. He received the Ernest J. Houdry Award in Applied Catalysis, the E. V. Murphree Award in Industrial and Engineering Chemistry in 1974, and the Richard J. Kokes Memorial Award and Lectureship from Johns Hopkins University in 1971. Bloch was elected to the National Academy of Sciences in 1975. == Career == Bloch was born in Chicago, Illinois. His parents were Ukrainian-Jewish immigrants Aaron and Esther Bloch. He received his B.A. and Ph.D. in organic chemistry in 1936 from the University of Chicago. == References == == External links == James P. Shoffner, "Herman Samuel Bloch", Biographical Memoirs of the National Academy of Sciences (2005)
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{
"page_id": 34081881,
"source": null,
"title": "Herman S. Bloch"
}
|
The Joint Center for Artificial Photosynthesis (JCAP), founded in 2010, is a (DOE) Energy Innovation Hub whose primary mission is to find a cost-effective method to produce fuels using only sunlight, water, and carbon-dioxide. The program has a budget of $122M over five years, subject to Congressional appropriation. The Director of JCAP is Professor Harry Atwater of Caltech and its two main centers are located at the California Institute of Technology and the Lawrence Berkeley National Laboratory. In addition, JCAP has partners from Stanford University, the University of California at Berkeley, University of California at Santa Barbara, University of California at Irvine, the University of California at San Diego, and Stanford Linear Accelerator. In addition, JCAP also serves as a hub for other solar fuels research teams across the United States, including 20 DOE Energy Frontier Research Center. In Obama's 2011 State of the Union address, he mentioned the Joint Center for Artificial Photosynthesis. Specifically, he said, "We're issuing a challenge. We're telling America's scientists and engineers that if they assemble teams of the best minds in their fields, and focus on the hardest problems in clean energy, we'll fund the Apollo projects of our time. At the California Institute of Technology, they're developing a way to turn sunlight and water into fuel for our cars". == See also == Artificial Photosynthesis == References == == External links == DOE website about JCAP JCAP Official Website
|
{
"page_id": 33688667,
"source": null,
"title": "Joint Center for Artificial Photosynthesis"
}
|
Microbial symbiosis in marine animals was not discovered until 1981. In the time following, symbiotic relationships between marine invertebrates and chemoautotrophic bacteria have been found in a variety of ecosystems, ranging from shallow coastal waters to deep-sea hydrothermal vents. Symbiosis is a way for marine organisms to find creative ways to survive in a very dynamic environment. They are different in relation to how dependent the organisms are on each other or how they are associated. It is also considered a selective force behind evolution in some scientific aspects. The symbiotic relationships of organisms has the ability to change behavior, morphology and metabolic pathways. With increased recognition and research, new terminology also arises, such as holobiont, which the relationship between a host and its symbionts as one grouping. Many scientists will look at the hologenome, which is the combined genetic information of the host and its symbionts. These terms are more commonly used to describe microbial symbionts. The type of marine animal vary greatly, for example, sponges, sea squirts, corals, worms, and algae all host a variety of unique symbionts. Each symbiotic relationship displays a unique ecological niche, which in turn can lead to entirely new species of host species and symbiont. It is particularly interesting that it took so long to discover the marine microbial symbiosis because nearly every surface submerged in the oceans becomes covered with biofilm, including a large number of living organisms. Many marine organisms display symbiotic relationships with microbes. Epibiotic bacteria have been found to live on crustacean larvae and protect them from fungal infections. Other microbes in deep-sea vents have been found to prevent the settlement of barnacles and tunicate larvae. == Mechanisms of symbiosis == Various mechanisms are utilized in order to facilitate symbiotic relationships and to help these associates evolve alongside one
|
{
"page_id": 46861405,
"source": null,
"title": "Marine microbial symbiosis"
}
|
another. By using horizontal gene transfer, certain genetic elements are able to pass from one organisms to another. In non-mating species, this helps with genetic differentiation and adaptive evolution. An example of this is the sponge Astroclera willeyana which has a gene that is used in expressing spherulite-forming cells which has an origin in bacteria. Another example is the starlet sea anemone, Nematostella vectensis, which has genes from bacteria that have a role in producing UV radiation protection in the form of shikimic acid. Another way for symbiotic relationships to co-evolve is through genome erosion. This is a process where genes that are typically used during free-living periods aren't necessary because of the symbioses of the organisms. Without that gene, the organism is able to decrease the energy necessary for cell maintenance and replication. == Types of symbiotic relationships == There are a variety of symbiotic relationships: Mutualism is a relationship in which both partners benefit. Commensalism is a relationship where one partner receives a benefit while the other is not affected. Parasitism is where one partner benefits at the expense of the host. Amensalism is a less common type of relationship where one organisms receives no benefit but the other still has negative ramifications. The relationship can be either an ectosymbiont, a symbiont that survives by being attached to the surface of the host, which includes areas such as the inner surfaces of the gut cavity, or even the ducts of endocrine glands; or an endosymbiont, a symbiont that lives within its host and can be known as an intracellular symbiont. They are further classified by their dependence on their host and can be a facultative symbiont that can exist in a free living condition and is not dependent on its host, or an obligate symbiont, which has adapted
|
{
"page_id": 46861405,
"source": null,
"title": "Marine microbial symbiosis"
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in such a way that it is not able to exit without the benefit it receives from its host. An example of an obligate symbioses is the relationship between microalgae and corals. The microalgae provides a large source of the coral diet == Some symbiotic relationships == === Coral reef symbiosis === The most notable display of marine symbiotic relationship would be coral. Coral reefs are home to a variety of dinoflagellate symbiont, these symbionts give coral its bright coloring and are vital for the survival of the reef. The symbionts provide the coral with food in exchange for protection. If the waters warm or become too acidic, the symbionts are expelled, the coral bleaches and if conditions persist the coral will die. This in turn leads to the collapse of the entire reef ecosystem === Bone eating worm symbiosis === Osedax, also called the bone eating worm is a siboglinid worm from polychaete genus. It was discovered in a whalefall community on the surface of bones, in the axis of Monterey Canyon, California, in 2002. Osedax lacks a mouth, a functional gut and a trophosome. But female osedax have a vascularized root system originating from their ovisac which contains heterotrophic endosymbiotic bacterial community dominated by γ-proteobacteria clade. They use the vascularized root system to access the whale bones. The endosymbionts help the host utilize nutrients from the whale bones. === Hawaiian squid and Vibrio fischeri symbiosis === Hawaiian sepiolid squid Euprymna scolopes and bacterium Vibrio fischeri also show symbiosis. In this symbiosis, symbiont not only serve the host for defense, but also shapes the host morphology. Bioluminescent V. fischeri can be found in epithelial lined crypts of the light organ of the host. Symbiosis begins as soon as a newly hatched squid finds and houses V. fischeri bacteria. The
|
{
"page_id": 46861405,
"source": null,
"title": "Marine microbial symbiosis"
}
|
symbiosis process begins when Peptidoglycan shed by the sea water bacteria comes in contact to the ciliated epithelial cells of the light organ. It induces mucus production in the cells. Mucus entraps bacterial cells. Antimicrobial peptides, nitric oxide and sialyted mucins in the mucus then selectively allow only V. fischeri which encode gene rscS to adhere and win over gram positive and other gram negative bacteria. The symbiotic bacteria are then guided up to the light organ via chemotaxis. After successful colonization, symbionts induce loss of mucus and ciliated sites to prevent further attachment of bacterial cells via MAMP (microbe associated molecular pattern) signalling. Also, they induce changes in protein expression in the host symbiotic tissues and modify both physiology and morphology of light organs. After bacterial cells divide and increase in population, they begin expressing enzyme luciferase as a result of quorum sensing. Luciferase enzymes produce bioluminescence. Squids can then emit the luminescence from the light organ. Because Euprymna scolopes emerges only during night time, it helps them avoid predation. Bioluminescence allows them to camouflage with the light coming from moon and stars to ocean and avoid predators. === Pompeii worm === Alvinella pompejana, the Pompeii worm is a polychaete, found in the far depths of the sea, typically found near hydrothermal vents. They were originally discovered by French researchers in the early 1980s. They can grow as large as 5 inches long and are normally described as having pale gray coloring with red "tentacle-like" gills protruding from their heads. Their tails are most likely found in temperatures as high as 176 degrees Fahrenheit, while their heads, which stick out from the tubes they live in are only exposed to temperatures as high as 72 degrees Fahrenheit. Its ability to survive the temperatures of hydrothermal vents lies in its
|
{
"page_id": 46861405,
"source": null,
"title": "Marine microbial symbiosis"
}
|
symbiotic relationship with the bacteria that resides on its back. It forms a "fleece-like" protective covering. Mucus is secreted from glands on the back of the Pompeii worm in order to provide nutrients for the bacteria. Further study of the bacteria led to the discovery that they are chemolithotrophic. === Hawaiian sea slug === Elysia rufescens grazes on Bryopsis sp., an alga that defends itself from predators by using peptide toxins with fatty acids, called kahalalides. A bacterial obligate symbiont produces many defensive molecules, including kahalalides, in order to protect the alga. This bacteria is able to use substrates derived from the host in order to synthesize the toxins. The Hawaiian Sea Slug grazes on the alga in order to accumulate kahalalide. This uptake of the toxin, which the slug is immune to, allows it to also become toxic to predators. This shared ability, both originating from the bacteria, provide protection within the marine ecosystems. === Marine sponges === Besides a one to one symbiotic relationship, it is possible for a host to become symbiotic with a microbial consortia. In the case of the sponge (phylum Porifera), they are able to host a lot of wide range of microbial communities that can also be very specific. The microbial communities that form a symbiotic relationship with the sponge can actually comprise up to 35% of the biomass of its host. The term for this specific symbiotic relationship, where a microbial consortia pairs with a host is called a holobiotic relationship. The sponge as well as the microbial community associated with it will produce a large range of secondary metabolites that help protect it against predators through mechanisms such as chemical defense. Some of these relationships include endosymbionts within bacteriocyte cells, and cyanobacteria or microalgae found below the pinacoderm cell layer where
|
{
"page_id": 46861405,
"source": null,
"title": "Marine microbial symbiosis"
}
|
they are able to receive the highest amount of light, used for phototrophy. They can host approximately 52 different microbial phyla and candidate phyla, including Alphaproteobacteria, Actinobacteria, Chloroflexi, Nitrospirae, Cyanobacteria, the taxa Gamma-, and the candidate phylum Poribacteria, and Thaumarchaea. === Endozoicomonas === This type of bacteria was first described in 2007. It is able to form symbiotic relationships with a wide range of hosts in the marine environment such as cnidarians, poriferans, molluscs, annelids, tunicates, and fish. They are distributed through various marine zones from extreme depths to warm photic zones. Endozoicomonas is thought to acquisition nutrients from nitrogen/carbon recycling, methane/sulfur recycling, and synthesize amino acids and various other molecules necessary for life. It was also found that it has a correlation to photosymbionts which provide carbon and sulfur to the bacteria from dimethylsulfopropionate (DMSP). They are also suspected to help regulate bacterial colonization of the host by using bioactive secondary metabolites or even probiotic mechanisms like limiting pathogenic bacteria by means of competitive exclusion. When Endozoicomonas is removed from the host, there are often signs of lesions on corals and disease. == Chemosynthetic symbioses in ocean == Marine environment consists of a large number of chemosynthetic symbioses in different regions of the ocean: shallow-water coastal sediments, continental slope sediments, whale and wood falls, cold seeps and deep-sea hydrothermal vents. Organisms from seven phyla (ciliophora, porifera, platyhelminthes, nematoda, mollusca, annelida and arthropoda) are known to have chemosynthetic symbiosis till now. Some of them include nematode, tube worms, clam, sponge, hydrothermal vent shrimp, worms mollusc, mussels and so on. The symbionts can be ectosymbionts or endosymbionts. Some ectosymbionts are: symbionts of polychaete worm Alvinella which occur in their dorsal surface and symbionts occurring on the mouthparts and gill chamber of the vent shrimp Rimicaris. Endosymbionts include symbionts of gastropod snails
|
{
"page_id": 46861405,
"source": null,
"title": "Marine microbial symbiosis"
}
|
which occur in their gill tissues. In the siboglinid tube worms of the groups Monilifera, Frenulata and Vestimentifera, symbionts can be found in an interior organ called trophosome. Most of the animals in deep-sea hydrothermal vents exist in a symbiotic relationship with chemosynthetic bacteria. These chemosynthetic bacteria are found to be methane or sulphur oxidizers. == Microbial biotechnology == Marine invertebrates are the hosts of a wide spectrum of bioactive metabolites, which have vast potential as drugs and research tools. In many cases, microbes aid in or are responsible for marine invertebrates natural products. Certain marine microbes can provide insight into the biosynthesis mechanisms of natural products, which in turn could solve the current limitations on marine drug development. == References ==
|
{
"page_id": 46861405,
"source": null,
"title": "Marine microbial symbiosis"
}
|
In machine learning (ML), a learning curve (or training curve) is a graphical representation that shows how a model's performance on a training set (and usually a validation set) changes with the number of training iterations (epochs) or the amount of training data. Typically, the number of training epochs or training set size is plotted on the x-axis, and the value of the loss function (and possibly some other metric such as the cross-validation score) on the y-axis. Synonyms include error curve, experience curve, improvement curve and generalization curve. More abstractly, learning curves plot the difference between learning effort and predictive performance, where "learning effort" usually means the number of training samples, and "predictive performance" means accuracy on testing samples. Learning curves have many useful purposes in ML, including: choosing model parameters during design, adjusting optimization to improve convergence, and diagnosing problems such as overfitting (or underfitting). Learning curves can also be tools for determining how much a model benefits from adding more training data, and whether the model suffers more from a variance error or a bias error. If both the validation score and the training score converge to a certain value, then the model will no longer significantly benefit from more training data. == Formal definition == When creating a function to approximate the distribution of some data, it is necessary to define a loss function L ( f θ ( X ) , Y ) {\displaystyle L(f_{\theta }(X),Y)} to measure how good the model output is (e.g., accuracy for classification tasks or mean squared error for regression). We then define an optimization process which finds model parameters θ {\displaystyle \theta } such that L ( f θ ( X ) , Y ) {\displaystyle L(f_{\theta }(X),Y)} is minimized, referred to as θ ∗ {\displaystyle \theta ^{*}} .
|
{
"page_id": 59968610,
"source": null,
"title": "Learning curve (machine learning)"
}
|
=== Training curve for amount of data === If the training data is { x 1 , x 2 , … , x n } , { y 1 , y 2 , … y n } {\displaystyle \{x_{1},x_{2},\dots ,x_{n}\},\{y_{1},y_{2},\dots y_{n}\}} and the validation data is { x 1 ′ , x 2 ′ , … x m ′ } , { y 1 ′ , y 2 ′ , … y m ′ } {\displaystyle \{x_{1}',x_{2}',\dots x_{m}'\},\{y_{1}',y_{2}',\dots y_{m}'\}} , a learning curve is the plot of the two curves i ↦ L ( f θ ∗ ( X i , Y i ) ( X i ) , Y i ) {\displaystyle i\mapsto L(f_{\theta ^{*}(X_{i},Y_{i})}(X_{i}),Y_{i})} i ↦ L ( f θ ∗ ( X i , Y i ) ( X i ′ ) , Y i ′ ) {\displaystyle i\mapsto L(f_{\theta ^{*}(X_{i},Y_{i})}(X_{i}'),Y_{i}')} where X i = { x 1 , x 2 , … x i } {\displaystyle X_{i}=\{x_{1},x_{2},\dots x_{i}\}} === Training curve for number of iterations === Many optimization algorithms are iterative, repeating the same step (such as backpropagation) until the process converges to an optimal value. Gradient descent is one such algorithm. If θ i ∗ {\displaystyle \theta _{i}^{*}} is the approximation of the optimal θ {\displaystyle \theta } after i {\displaystyle i} steps, a learning curve is the plot of i ↦ L ( f θ i ∗ ( X , Y ) ( X ) , Y ) {\displaystyle i\mapsto L(f_{\theta _{i}^{*}(X,Y)}(X),Y)} i ↦ L ( f θ i ∗ ( X , Y ) ( X ′ ) , Y ′ ) {\displaystyle i\mapsto L(f_{\theta _{i}^{*}(X,Y)}(X'),Y')} == See also == Overfitting Bias–variance tradeoff Model selection Cross-validation (statistics) Validity (statistics) Verification and validation Double descent == References ==
|
{
"page_id": 59968610,
"source": null,
"title": "Learning curve (machine learning)"
}
|
In biology, saltation (from Latin saltus 'leap, jump') is a sudden and large mutational change from one generation to the next, potentially causing single-step speciation. This was historically offered as an alternative to Darwinism. Some forms of mutationism were effectively saltationist, implying large discontinuous jumps. Speciation, such as by polyploidy in plants, can sometimes be achieved in a single and in evolutionary terms sudden step. Evidence exists for various forms of saltation in a variety of organisms. == History == Prior to Charles Darwin most evolutionary scientists had been saltationists. Jean-Baptiste Lamarck was a gradualist but similar to other scientists of the period had written that saltational evolution was possible. Étienne Geoffroy Saint-Hilaire endorsed a theory of saltational evolution that "monstrosities could become the founding fathers (or mothers) of new species by instantaneous transition from one form to the next." Geoffroy wrote that environmental pressures could produce sudden transformations to establish new species instantaneously. In 1864 Albert von Kölliker revived Geoffroy's theory that evolution proceeds by large steps, under the name of heterogenesis. With the publication of On the Origin of Species in 1859 Charles Darwin wrote that most evolutionary changes proceeded gradually. From 1860 to 1880 saltation had a minority interest but by 1890 had become a major interest to scientists. In their paper on evolutionary theories in the 20th century Levit et al wrote: The advocates of saltationism deny the Darwinian idea of slowly and gradually growing divergence of character as the only source of evolutionary progress. They would not necessarily completely deny gradual variation, but claim that cardinally new ‘body plans’ come into being as a result of saltations (sudden, discontinuous and crucial changes, for example, the series of macromutations). The latter are responsible for the sudden appearance of new higher taxa including classes and orders, while
|
{
"page_id": 4131939,
"source": null,
"title": "Saltation (biology)"
}
|
small variation is supposed to be responsible for the fine adaptations below the species level. In the early 20th century a mechanism of saltation was proposed as large mutations. It was seen as a much faster alternative to the Darwinian concept of a gradual process of small random variations being acted on by natural selection. It was popular with early geneticists such as Hugo de Vries, who along with Carl Correns helped rediscover Gregor Mendel's laws of inheritance in 1900, William Bateson, a British zoologist who switched to genetics, and early in his career Thomas Hunt Morgan. Some of these geneticists developed it into the mutation theory of evolution. There was also a debate over accounts of the evolution of mimicry and if they could be explained by gradualism or saltation. The geneticist Reginald Punnett supported a saltational theory in his book Mimicry in Butterflies (1915). The mutation theory of evolution held that species went through periods of rapid mutation, possibly as a result of environmental stress, that could produce multiple mutations, and in some cases completely new species, in a single generation. This mutationist view of evolution was later replaced by the reconciliation of Mendelian genetics with natural selection into a gradualistic framework for the neo-Darwinian synthesis. It was the emergence of population thinking in evolution which forced many scientists to adopt gradualism in the early 20th century. According to Ernst Mayr, it wasn't until the development of population genetics in the neo-Darwinian synthesis in the 1940s that demonstrated the explanatory power of natural selection that saltational views of evolution were largely abandoned. Saltation was originally denied by the "modern synthesis" school of neo-Darwinism which favoured gradual evolution but has since been accepted due to recent evidence in evolutionary biology (see the current status section). In recent years there
|
{
"page_id": 4131939,
"source": null,
"title": "Saltation (biology)"
}
|
are some prominent proponents of saltation, including Carl Woese. Woese, and colleagues, suggested that the absence of RNA signature continuum between domains of bacteria, archaea, and eukarya constitutes a primary indication that the three primary organismal lineages materialized via one or more major evolutionary saltations from some universal ancestral state involving dramatic change in cellular organization that was significant early in the evolution of life, but in complex organisms gave way to the generally accepted Darwinian mechanisms. The geneticist Barbara McClintock introduced the idea of "jumping genes", chromosome transpositions that can produce rapid changes in the genome. Saltational speciation, also known as abrupt speciation, is the discontinuity in a lineage that occurs through genetic mutations, chromosomal aberrations or other evolutionary mechanisms that cause reproductively isolated individuals to establish a new species population. Polyploidy, karyotypic fission, symbiogenesis and lateral gene transfer are possible mechanisms for saltational speciation. == Macromutation theory == The botanist John Christopher Willis proposed an early saltationist theory of evolution. He held that species were formed by large mutations, not gradual evolution by natural selection. The German geneticist Richard Goldschmidt was the first scientist to use the term "hopeful monster". Goldschmidt thought that small gradual changes could not bridge the hypothetical divide between microevolution and macroevolution. In his book The Material Basis of Evolution (1940) he wrote "the change from species to species is not a change involving more and more additional atomistic changes, but a complete change of the primary pattern or reaction system into a new one, which afterwards may again produce intraspecific variation by micromutation." Goldschmidt believed the large changes in evolution were caused by macromutations (large mutations). His ideas about macromutations became known as the hopeful monster hypothesis which is considered a type of saltational evolution. Goldschmidt's thesis however was universally rejected and widely
|
{
"page_id": 4131939,
"source": null,
"title": "Saltation (biology)"
}
|
ridiculed within the biological community, which favored the neo-Darwinian explanations of R.A. Fisher, J. B. S. Haldane and Sewall Wright. However, there has been a recent interest in the ideas of Goldschmidt in the field of evolutionary developmental biology as some scientists are convinced he was not entirely wrong. Otto Schindewolf, a German paleontologist, also supported macromutations as part of his evolutionary theory. He was known for presenting an alternative interpretation of the fossil record based on his ideas of orthogenesis, saltational evolution and extraterrestrial impacts opposed to gradualism but abandoned the view of macromutations in later publications. Søren Løvtrup, a biochemist and embryologist from Denmark, advocated a similar hypothesis of macromutation to Goldschmidt's in 1974. Lovtrup believed that macromutations interfered with various epigenetic processes, that is, those which affect the causal processes in biological development. This is in contrast to the gradualistic theory of micromutations of Neo-Darwinism, which claims that evolutionary innovations are generally the result of accumulation of numerous very slight modifications. Lovtrup also rejected the punctuated equilibria of Stephen Gould and Niles Eldredge, claiming it was a form of gradualism and not a macromutation theory. Lovtrup defended many of Darwin's critics including Schindewolf, Mivart, Goldschmidt, and Himmelfarb. Mae Wan Ho described Lovtrup's theory as similar to the hopeful monster theory of Richard Goldschmidt. Goldschmidt presented two mechanisms for how hopeful monsters might work. One mechanism, involved “systemic mutations”, rejected the classical gene concept and is no longer considered by modern science; however, his second mechanism involved “developmental macromutations” in “rate genes” or “controlling genes” that change early development and thus cause large effects in the adult phenotype. These kind of mutations are similar to the ones considered in contemporary evolutionary developmental biology. On the subject of Goldschmidt Donald Prothero in his book Evolution: What the Fossils Say
|
{
"page_id": 4131939,
"source": null,
"title": "Saltation (biology)"
}
|
and Why It Matters (2007) wrote: The past twenty years have vindicated Goldschmidt to some degree. With the discovery of the importance of regulatory genes, we realize that he was ahead of his time in focusing on the importance of a few genes controlling big changes in the organisms, not small-scales changes in the entire genome as neo-Darwinians thought. In addition, the hopeful monster problem is not so insurmountable after all. Embryology has shown that if you affect an entire population of developing embryos with a stress (such as a heat shock) it can cause many embryos to go through the same new pathway of embryonic development, and then they all become hopeful monsters when they reach reproductive age. In 2008 evolutionary biologist Olivia Judson in her article The Monster Is Back, and It’s Hopeful listed some examples which may support the hopeful monster hypothesis and an article published in the journal Nature in 2010 titled Evolution: Revenge of the Hopeful Monster reported that studies in stickleback populations in a British Columbia lake and bacteria populations in a Michigan lab have shown that large individual genetic changes can have vast effects on organisms "without dooming it to the evolutionary rubbish heap". According to the article "Single-gene changes that confer a large adaptive value do happen: they are not rare, they are not doomed and, when competing with small-effect mutations, they tend to win. But small-effect mutations still matter — a lot. They provide essential fine-tuning and sometimes pave the way for explosive evolution to follow." A paper by (Page et al. 2010) have written that the Mexican axolotl (Ambystoma mexicanum) could be classified as a hopeful monster as it exhibits an adaptive and derived mode of development that has evolved rapidly and independently among tiger salamanders. According to the paper
|
{
"page_id": 4131939,
"source": null,
"title": "Saltation (biology)"
}
|
there has been an interest in aspects of the hopeful monster hypothesis in recent years: Goldschmidt proposed that mutations occasionally yield individuals within populations that deviate radically from the norm and referred to such individuals as "hopeful monsters". If the novel phenotypes of hopeful monsters arise under the right environmental circumstances, they may become fixed, and the population will found a new species. While this idea was discounted during the Modern synthesis, aspects of the hopeful monster hypothesis have been substantiated in recent years. For example, it is clear that dramatic changes in phenotype can occur from few mutations of key developmental genes and phenotypic differences among species often map to relatively few genetic factors. These findings are motivating renewed interest in the study of hopeful monsters and the perspectives they can provide about the evolution of development. In contrast to mutants that are created in the lab, hopeful monsters have been shaped by natural selection and are therefore more likely to reveal mechanisms of adaptive evolution. Günter Theissen, a German professor of genetics, has classified homeotic mutants as "hopeful monsters" and has documented many examples of animal and plant lineages that may have originated in that way. American biologist Michael Freeling has proposed "balanced gene drive" as a saltational mechanism in the mutationist tradition, which could explain trends involving morphological complexity in plant and animal eukaryotic lineages. == Current status == === Known mechanisms === Examples of saltational evolution include cases of stabilized hybrids that can reproduce without crossing (such as allotetraploids) and cases of symbiogenesis. Both gene duplication and lateral gene transfer have the capacity to bring about relatively large changes that are saltational. Polyploidy (most common in plants but not unknown in animals) is saltational: a significant change (in gene numbers) can result in speciation in a
|
{
"page_id": 4131939,
"source": null,
"title": "Saltation (biology)"
}
|
single generation. === Claimed instances === Evidence of phenotypic saltation has been found in the centipede and some scientists have suggested there is evidence for independent instances of saltational evolution in sphinx moths. Saltational changes have occurred in the buccal cavity of the roundworm Caenorhabditis elegans. Some processes of epigenetic inheritance can also produce changes that are saltational. There has been a controversy over whether mimicry in butterflies and other insects can be explained by gradual or saltational evolution. According to Norrström (2006) there is evidence for saltation in some cases of mimicry. The endosymbiotic theory is considered to be a type of saltational evolution. Symonds and Elgar, 2004 have suggested that pheromone evolution in bark beetles is characterized by large saltational shifts. The mode of evolution of sex pheromones in Bactrocera has occurred by rapid saltational changes associated with speciation followed by gradual divergence thereafter. Saltational speciation has been recognized in the genus Clarkia (Lewis, 1966). It has been suggested (Carr, 1980, 2000) that the Calycadenia pauciflora could have originated directly from an ancestral race through a single saltational event involving multiple chromosome breaks. Specific cases of homeosis in flowers can be caused by saltational evolution. In a study of divergent orchid flowers (Bateman and DiMichele, 2002) wrote how simple homeotic morphs in a population can lead to newly established forms that become fixed and ultimately lead to new species. They described the transformation as a saltational evolutionary process, where a mutation of key developmental genes leads to a profound phenotypic change, producing a new evolutionary lineage within a species. === Explanations === Reviewing the history of macroevolutionary theories, the American evolutionary biologist Douglas J. Futuyma notes that since 1970, two very different alternatives to Darwinian gradualism have been proposed, both by Stephen Jay Gould: mutationism, and punctuated equilibria.
|
{
"page_id": 4131939,
"source": null,
"title": "Saltation (biology)"
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|
Gould's macromutation theory gave a nod to his predecessor with an envisaged "Goldschmidt break" between evolution within a species and speciation. His advocacy of Goldschmidt was attacked with "highly unflattering comments" by B. Charlesworth and Templeton. Futuyma concludes, following other biologists reviewing the field such as K.Sterelny and A. Minelli, that essentially all the claims of evolution driven by large mutations could be explained within the Darwinian evolutionary synthesis. == See also == Catastrophism Phyletic gradualism Rapid modes of evolution Leo S. Berg History of evolutionary thought Eclipse of Darwinism == Footnotes == == Sources == == External links == New species evolve in bursts by Kerri Smith
|
{
"page_id": 4131939,
"source": null,
"title": "Saltation (biology)"
}
|
The pudendal canal (also called Alcock's canal) is an anatomical structure formed by the obturator fascia (fascia of the obturator internus muscle) lining the lateral wall of the ischioanal fossa. The internal pudendal artery and veins, and pudendal nerve pass through the pudendal canal, and the perineal nerve arises within it. == Clinical significance == Pudendal nerve entrapment can occur when the pudendal nerve is compressed while it passes through the pudendal canal. == History == The pudendal canal is also known as Alcock's canal, named after Benjamin Alcock. == Additional images == == See also == Femoral canal Inguinal canal Pudendal nerve Obturator internus muscle == References == This article incorporates text in the public domain from page 421 of the 20th edition of Gray's Anatomy (1918) == External links == Anatomy image: apmalefrontal4-16 at the College of Medicine at SUNY Upstate Medical University Cross section image: pelvis/pelvis-e12-15—Plastination Laboratory at the Medical University of Vienna Anatomy photo:41:08-0100 at the SUNY Downstate Medical Center — "The Female Perineum: Contents of the Pudendal Canal" Diagram at pudendal.info Anatomy image:9087 at the SUNY Downstate Medical Center Anatomy image:9448 at the SUNY Downstate Medical Center
|
{
"page_id": 4787300,
"source": null,
"title": "Pudendal canal"
}
|
In particle physics, the Glashow resonance is the resonant formation of the W boson in antineutrino-electron collisions: νe + e− → W−. == History == The resonance was proposed by Sheldon Glashow in 1959. == Theory == The threshold antineutrino energy for this process (for the electron at rest in the laboratory frame) is given by the formula E ν = M W 2 c 2 − ( m e 2 + m ν 2 ) c 2 2 m e ≈ M W 2 c 2 2 m e {\displaystyle E_{\nu }={\frac {M_{W}^{2}c^{2}-(m_{e}^{2}+m_{\nu }^{2})c^{2}}{2m_{e}}}\approx {\frac {M_{W}^{2}c^{2}}{2m_{e}}}} (here is, for completeness, included also the antineutrino mass, which vanishes in the Standard Model), which gives 6.3 PeV, a huge energy for a fundamental particle. This process is considered for the detection and studies of high-energy cosmic neutrinos at the IceCube experiment, at the ANTARES neutrino telescope, and at the KM3NeT neutrino telescope. == Detection == A report observing the resonance at 2.3σ level has been made by the IceCube experiment in March 2021. == References ==
|
{
"page_id": 42208364,
"source": null,
"title": "Glashow resonance"
}
|
The Ignaz Lieben Prize, named after the Austrian banker Ignaz Lieben, is an annual Austrian award made by the Austrian Academy of Sciences to young scientists working in the fields of molecular biology, chemistry, or physics. == Biography == The Ignaz Lieben Prize has been called the Austrian Nobel Prize. It is similar in intent but somewhat older than the Nobel Prize. The Austrian merchant Ignaz L. Lieben, whose family supported many philanthropic activities, had stipulated in his testament that 6,000 florins should be used “for the common good”. In 1863 this money was given to the Austrian Imperial Academy of Sciences, and the Ignaz L. Lieben Prize was instituted. Every three years, the sum of 900 florins was to be given to an Austrian scientist in the field of chemistry, physics, or physiology. This sum corresponded to roughly 40 per cent of the annual income of a university professor. From 1900 on, the prize was offered on a yearly basis. The endowment was twice increased by the Lieben family. When the endowment had lost its value due to inflation after World War I, the family transferred the necessary sum yearly to the Austrian Academy of Sciences. But since the family was persecuted by the National Socialists, the prize was discontinued after the German Anschluss of Austria in 1938. Richard Lieben (1842–1919), the younger son of Ignaz Lieben, financed the Richard Lieben Prize in Mathematics, which was awarded every three years from 1912 to 1921, and one final time in 1928, before being discontinued. In 2004 the Lieben prize was reinstated, with support from Isabel Bader and Alfred Bader (who was able to flee from Austria to Great Britain at the age of fourteen in 1938). Now, the award amounts to US Dollar 36,000, and it is offered yearly to
|
{
"page_id": 9440365,
"source": null,
"title": "Lieben Prize"
}
|
young scientists who work in Austria, Bosnia-Herzegovina, Croatia, the Czech Republic, Hungary, Slovakia or Slovenia (i.e., in one of the countries that were part of the Austro-Hungarian Empire a hundred years ago), and who work in the fields of molecular biology, chemistry, or physics. == Laureates == Source (1865–1937; 2004–2007): Ignaz Lieben Gesellschaft: === Richard Lieben Prize === 1912 Josip Plemelj 1915 Gustav Herglotz 1918 Wilhelm Gross 1921 Hans Hahn and Johann Radon 1928 Karl Menger == See also == List of biology awards List of chemistry awards List of physics awards == References == == External links == Official website (in English and German)
|
{
"page_id": 9440365,
"source": null,
"title": "Lieben Prize"
}
|
Infinite divisibility arises in different ways in philosophy, physics, economics, order theory (a branch of mathematics), and probability theory (also a branch of mathematics). One may speak of infinite divisibility, or the lack thereof, of matter, space, time, money, or abstract mathematical objects such as the continuum. == In philosophy == The origin of the idea in the Western tradition can be traced to the 5th century BCE starting with the Ancient Greek pre-Socratic philosopher Democritus and his teacher Leucippus, who theorized matter's divisibility beyond what can be perceived by the senses until ultimately ending at an indivisible atom. The Indian philosopher, Maharshi Kanada also proposed an atomistic theory, however there is ambiguity around when this philosopher lived, ranging from sometime between the 6th century to 2nd century BCE. Around 500 BC, he postulated that if we go on dividing matter (padarth), we shall get smaller and smaller particles. Ultimately, a time will come when we shall come across the smallest particles beyond which further division will not be possible. He named these particles Parmanu. Another Indian philosopher, Pakudha Katyayama, elaborated this doctrine and said that these particles normally exist in a combined form which gives us various forms of matter. Atomism is explored in Plato's dialogue Timaeus. Aristotle proves that both length and time are infinitely divisible, refuting atomism. Andrew Pyle gives a lucid account of infinite divisibility in the first few pages of his Atomism and its Critics. There he shows how infinite divisibility involves the idea that there is some extended item, such as an apple, which can be divided infinitely many times, where one never divides down to point, or to atoms of any sort. Many philosophers claim that infinite divisibility involves either a collection of an infinite number of items (since there are infinite divisions,
|
{
"page_id": 855150,
"source": null,
"title": "Infinite divisibility"
}
|
there must be an infinite collection of objects), or (more rarely), point-sized items, or both. Pyle states that the mathematics of infinitely divisible extensions involve neither of these — that there are infinite divisions, but only finite collections of objects and they never are divided down to point extension-less items. In Zeno's arrow paradox, Zeno questioned how an arrow can move if at one moment it is here and motionless and at a later moment be somewhere else and motionless. Zeno's reasoning, however, is fallacious, when he says that if everything when it occupies an equal space is at rest, and if that which is in locomotion is always occupying such a space at any moment, the flying arrow is therefore motionless. This is false, for time is not composed of indivisible moments any more than any other magnitude is composed of indivisibles. In reference to Zeno's paradox of the arrow in flight, Alfred North Whitehead writes that "an infinite number of acts of becoming may take place in a finite time if each subsequent act is smaller in a convergent series": The argument, so far as it is valid, elicits a contradiction from the two premises: (i) that in a becoming something (res vera) becomes, and (ii) that every act of becoming is divisible into earlier and later sections which are themselves acts of becoming. Consider, for example, an act of becoming during one second. The act is divisible into two acts, one during the earlier half of the second, the other during the later half of the second. Thus that which becomes during the whole second presupposes that which becomes during the first half-second. Analogously, that which becomes during the first half-second presupposes that which becomes during the first quarter-second, and so on indefinitely. Thus if we consider
|
{
"page_id": 855150,
"source": null,
"title": "Infinite divisibility"
}
|
the process of becoming up to the beginning of the second in question, and ask what then becomes, no answer can be given. For, whatever creature we indicate presupposes an earlier creature which became after the beginning of the second and antecedently to the indicated creature. Therefore there is nothing which becomes, so as to effect a transition into the second in question. == In quantum physics == Until the discovery of quantum mechanics, no distinction was made between the question of whether matter is infinitely divisible and the question of whether matter can be cut into smaller parts ad infinitum. As a result, the Greek word átomos (ἄτομος), which literally means "uncuttable", is usually translated as "indivisible". Whereas the modern atom is indeed divisible, it actually is uncuttable: there is no partition of space such that its parts correspond to material parts of the atom. In other words, the quantum-mechanical description of matter no longer conforms to the cookie cutter paradigm. This casts fresh light on the ancient conundrum of the divisibility of matter. The multiplicity of a material object—the number of its parts—depends on the existence, not of delimiting surfaces, but of internal spatial relations (relative positions between parts), and these lack determinate values. According to the Standard Model of particle physics, the particles that make up an atom—quarks and electrons—are point particles: they do not take up space. What makes an atom nevertheless take up space is not any spatially extended "stuff" that "occupies space", and that might be cut into smaller and smaller pieces, but the indeterminacy of its internal spatial relations. Physical space is often regarded as infinitely divisible: it is thought that any region in space, no matter how small, could be further split. Time is similarly considered as infinitely divisible. However, according to
|
{
"page_id": 855150,
"source": null,
"title": "Infinite divisibility"
}
|
the best currently accepted theory in physics, the Standard Model, there is a distance (called the Planck length, 1.616229(38)×10−35 metres, named after one of the fathers of Quantum Theory, Max Planck) and therefore a time interval (the amount of time which light takes to traverse that distance in a vacuum, 5.39116(13) × 10−44 seconds, known as the Planck time) at which the Standard Model is expected to break down – effectively making this the smallest physical scale about which meaningful statements can be currently made. To predict the physical behaviour of space-time and fundamental particles at smaller distances requires a new theory of Quantum Gravity, which unifies the hitherto incompatible theories of Quantum Mechanics and General Relativity. == In economics == One dollar, or one euro, is divided into 100 cents; one can only pay in increments of a cent. It is quite commonplace for prices of some commodities such as gasoline to be in increments of a tenth of a cent per gallon or per litre. If gasoline costs $3.979 per gallon and one buys 10 gallons, then the "extra" 9/10 of a cent comes to ten times that: an "extra" 9 cents, so the cent in that case gets paid. Money is infinitely divisible in the sense that it is based upon the real number system. However, modern day coins are not divisible (in the past some coins were weighed with each transaction, and were considered divisible with no particular limit in mind). There is a point of precision in each transaction that is useless because such small amounts of money are insignificant to humans. The more the price is multiplied the more the precision could matter. For example, when buying a million shares of stock, the buyer and seller might be interested in a tenth of a
|
{
"page_id": 855150,
"source": null,
"title": "Infinite divisibility"
}
|
cent price difference, but it's only a choice. Everything else in business measurement and choice is similarly divisible to the degree that the parties are interested. For example, financial reports may be reported annually, quarterly, or monthly. Some business managers run cash-flow reports more than once per day. Although time may be infinitely divisible, data on securities prices are reported at discrete times. For example, if one looks at records of stock prices in the 1920s, one may find the prices at the end of each day, but perhaps not at three-hundredths of a second after 12:47 PM. A new method, however, theoretically, could report at double the rate, which would not prevent further increases of velocity of reporting. Perhaps paradoxically, technical mathematics applied to financial markets is often simpler if infinitely divisible time is used as an approximation. Even in those cases, a precision is chosen with which to work, and measurements are rounded to that approximation. In terms of human interaction, money and time are divisible, but only to the point where further division is not of value, which point cannot be determined exactly. == In order theory == To say that the field of rational numbers is infinitely divisible (i.e. order theoretically dense) means that between any two rational numbers there is another rational number. By contrast, the ring of integers is not infinitely divisible. Infinite divisibility does not imply gaplessness: the rationals do not enjoy the least upper bound property. That means that if one were to partition the rationals into two non-empty sets A and B where A contains all rationals less than some irrational number (π, say) and B all rationals greater than it, then A has no largest member and B has no smallest member. The field of real numbers, by contrast, is
|
{
"page_id": 855150,
"source": null,
"title": "Infinite divisibility"
}
|
both infinitely divisible and gapless. Any linearly ordered set that is infinitely divisible and gapless, and has more than one member, is uncountably infinite. For a proof, see Cantor's first uncountability proof. Infinite divisibility alone implies infiniteness but not uncountability, as the rational numbers exemplify. == In probability distributions == To say that a probability distribution F on the real line is infinitely divisible means that if X is any random variable whose distribution is F, then for every positive integer n there exist n independent identically distributed random variables X1, ..., Xn whose sum is equal in distribution to X (those n other random variables do not usually have the same probability distribution as X). The Poisson distribution, the stuttering Poisson distribution, the negative binomial distribution, and the Gamma distribution are examples of infinitely divisible distributions — as are the normal distribution, Cauchy distribution and all other members of the stable distribution family. The skew-normal distribution is an example of a non-infinitely divisible distribution. (See Domínguez-Molina and Rocha-Arteaga (2007).) Every infinitely divisible probability distribution corresponds in a natural way to a Lévy process, i.e., a stochastic process { Xt : t ≥ 0 } with stationary independent increments (stationary means that for s < t, the probability distribution of Xt − Xs depends only on t − s; independent increments means that that difference is independent of the corresponding difference on any interval not overlapping with [s, t], and similarly for any finite number of intervals). This concept of infinite divisibility of probability distributions was introduced in 1929 by Bruno de Finetti. == See also == Divisible group, a mathematical group in which every element is an arbitrary multiple of some other element Indecomposable distribution Salami slicing Zeno's paradoxes == References == Domínguez-Molina, J.A.; Rocha-Arteaga, A. (2007) "On the
|
{
"page_id": 855150,
"source": null,
"title": "Infinite divisibility"
}
|
Infinite Divisibility of some Skewed Symmetric Distributions". Statistics and Probability Letters, 77 (6), 644–648 doi:10.1016/j.spl.2006.09.014 == External links == Infinite Hierarchical Nesting of Matter (translation of Russian Wikipedia page)
|
{
"page_id": 855150,
"source": null,
"title": "Infinite divisibility"
}
|
An aglycone (aglycon or genin) is the chemical compound remaining after the glycosyl group on a glycoside is replaced by a hydrogen atom. For example, the aglycone of a cardiac glycoside would be a steroid molecule. == Detection == A way to identify aglycone is proposed to extract it from Agave spp. by using H-NMR and Heteronuclear multiple bond correlation (HMBC) experiments. The HMBC experiment can be combined with other techniques such as mass spectrometry to further examine the structure and the function of aglycone. Samples of glycones and glycosides from limonoids can be simultaneously quantified through a high performance liquid chromatography (HPLC) method, where a binary solvent system and a diode array detector separate and detect them at a sensitivity of 0.25-0.50 μg. == Clinical significance == A study on molecular markers in human aortic endothelial cells published that aglycone stopped cell migration but not monocyte adhesion, which is the initial step of atherosclerotic plaque formation. Another study exploring the benefits of extra virgin olive oil consumption in preventing age-related neurodegenerative diseases found aglycone greatly increased the cognitive performance of mice. The aglycone-fed mice displayed strong autophagic reactions, mTOR regulation, and reduced plaque deposits and β-amyloid levels. == See also == Glucoside == References == == External links == Media related to Glycoside aglycones at Wikimedia Commons
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{
"page_id": 2821231,
"source": null,
"title": "Aglycone"
}
|
Kureha Corporation (株式会社クレハ, Kabushiki-gaisha Kureha) is a Japanese manufacturer of specialty chemicals, polymers and agrichemicals. == Corporate affairs == Kureha Chemical Industries is a member of the Mizuho keiretsu. == Products == === Polyglycolic acid === One of the company's long-term investments is in polyglycolic acid (PGA). The company developed a mass scale manufacturing technique for the chemical, which has been a development project of the company since the early 90s. The company has stated a strategy of committing to invest in PGA for a long period, patiently waiting for market demand to develop. To manufacture PGA, the company invested 100 million in a manufacturing facility in Belle, West Virginia to be located nearby a Dupont plant that produces glycolic acid, a primary feedstock for PGA. === Polyphenylene sulfide === Kureha is the world's largest producer of polyphenylene sulfide, a heat-resistant polymer is used in industrial applications such as automotive electronics. The polymer its produced at the company's site in Iwaki, Japan and in Wilmington, United States by Fortron Industries, a joint venture of Kureha and Celanese. == References == == External links == Official global website (in English)
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{
"page_id": 46795887,
"source": null,
"title": "Kureha Corporation"
}
|
CC chemokine receptors (or beta chemokine receptors) are integral membrane proteins that specifically bind and respond to cytokines of the CC chemokine family. They represent one subfamily of chemokine receptors, a large family of G protein-linked receptors that are known as seven transmembrane (7-TM) proteins since they span the cell membrane seven times. To date, ten true members of the CC chemokine receptor subfamily have been described. These are named CCR1 to CCR10 according to the IUIS/WHO Subcommittee on Chemokine Nomenclature. == Mechanism == The CC chemokine receptors all work by activating the G protein Gi. == Types == === Overview table === === CCR1 === CCR1 was the first CC chemokine receptor identified and binds multiple inflammatory/inducible (see inducible gene) CC chemokines (including CCL4, CCL5, CCL6, CCL14, CCL15, CCL16 and CCL23). In humans, this receptor can be found on peripheral blood lymphocytes and monocytes. There is some suggestion that this chemokine receptor is restricted to memory T-cells within the lymphocyte pool. This receptor is also designated cluster of differentiation marker CD191. === CCR2 === CCR2 can interact with CCL2, CCL8 and CCL16 and has been identified on the surface of monocytes, activated memory T cells, B cells, and basophils in humans, and also in peritoneal macrophages in mice. CCR2 is also designated CD192. === CCR3 === CCR3 is a receptor for multiple inflammatory/inducible CC chemokines, including CCL11, CCL26, CCL7, CCL13, CCL15, CCL24 and CCL5 that attract eosinophils, and CCL28 that attracts B and T lymphocytes to mucosal tissues. It is most highly expressed in both eosinophils and basophils, but can also be found in Th1 and Th2 cells and airway epithelial cells. Thus CCR3 plays a role in allergic reactions. CCR3 is also known as CD193. === CCR4 === CCR4 is expressed on Th2 T lymphocytes and is up-regulated
|
{
"page_id": 9833587,
"source": null,
"title": "CC chemokine receptors"
}
|
by T cell receptor activation. However, some reports suggest a role for this receptor also in trafficking of dendritic cells. The CC chemokines CCL3, CCL5, CCL17 and CCL22 signal through this receptor. === CCR5 === CCR5 is expressed on several cell types including peripheral blood-derived dendritic cells, CD34+ hematopoietic progenitor cells and certain activated/memory Th1 lymphocytes. This receptor is well defined as a major coreceptor implicated in susceptibility to HIV-1 infection and disease. This receptor has several CC chemokine ligands including CCL2, CCL3, CCL4, CCL5, CCL11, CCL13, CCL14 and CCL16. === CCR6 === CCR6, a receptor for CCL20, is expressed on unactivated memory T-cells and some dendritic cells. CCR6 is also expressed on Th17 cells. CCR6 is down-regulated in activated T-cells. === CCR7 === CCR7 is a highly important receptor with a role in trafficking of B and T lymphocytes and dendritic cells to and across high endothelial venules and positioning those cells correctly in T cell zones of secondary lymphoid organs. Its ligands include the related chemokines CCL19 and CCL21, (previously called ELC and SLC). === CCR8 === CCR8 is associated with Th2 lymphocytes and is therefore found predominantly in the thymus (in humans) although some expression can be found in the brain, spleen, lymph node, and monocytes at the nucleotide level. The ligands for this receptor are CCL1 and CCL16 === CCR9 === CCR9 was previously called orphan receptor GPR 9-6 and is very highly expressed in thymus (on both immature and mature T-cells) while low in lymph nodes and spleen. CCR9 is also abundant in the gut, with its expression associated with T cells of the intestine. The specific ligand of this receptor is CCL25 To note, the chemokine binding protein D6 had previously been named CCR9, but this molecule is a scavenger receptor not a true
|
{
"page_id": 9833587,
"source": null,
"title": "CC chemokine receptors"
}
|
(signaling) chemokine receptor. === CCR10 === CCR10 is receptor for CCL27 and CCL28 that was originally called orphan receptor GPR2. CCR10 has been implicated in inflammation of the skin, and has been shown to recruit regulatory T cells (Tregs) to mucosal layers. === CCR11 === This molecule was originally designated CCR11 due to its ability to bind several CC chemokines (including CCL19, CCL21 and CCL25) and its structural similarity to chemokine receptors. However, due to the inability of this molecule (also known as CCRL1 and CCX CKR) to generate a signal following ligand interaction, it has been suggested that it is a scavenger receptor for chemokines and not a bona fide chemokine receptor. Thus CCRL1 should not be called CCR11 under the guidelines of the IUIS/WHO Subcommittee on Chemokine Nomenclature. == References == == External links == "Chemokine Receptors". IUPHAR Database of Receptors and Ion Channels. International Union of Basic and Clinical Pharmacology. Archived from the original on 2016-03-03. Retrieved 2008-11-25.
|
{
"page_id": 9833587,
"source": null,
"title": "CC chemokine receptors"
}
|
Moisture vapor transmission rate (MVTR), also water vapor transmission rate (WVTR), is a measure of the passage of water vapor through a substance. It is a measure of the permeability for vapor barriers. There are many industries where moisture control is critical. Moisture sensitive foods and pharmaceuticals are put in packaging with controlled MVTR to achieve the required quality, safety, and shelf life. In clothing, MVTR as a measure of breathability has contributed to greater comfort for wearers of clothing for outdoor activity. The building materials industry also manages the moisture barrier properties in architectural components to ensure the correct moisture levels in the internal spaces of buildings. Optoelectronic devices based on organic material, generally named OLEDs, need an encapsulation with low values of WVTR to guarantee the same performances over the lifetime of the device. MVTR generally decreases with increasing thickness of the film/barrier, and increases with increasing temperature. == Measurement == There are various techniques to measure MVTR, ranging from gravimetric techniques that measure the gain or loss of moisture by mass, to highly sophisticated instrumental techniques that in some designs can measure extremely low transmission rates. Special care has to be taken in measuring porous substances such as fabrics, as some techniques are not appropriate. For very low levels, many techniques do not have adequate resolution. Numerous standard methods are described in ISO, ASTM, BS, DIN etc.—these are quite often industry-specific. Instrument manufacturers are often able to provide test methods developed to fully exploit the specific design which they are selling. The search for the most appropriate instrument is a zealous task which is in itself part of the measurement. The conditions under which the measurement is made has a considerable influence on the result. Both the temperature and humidity gradients across the sample need to be
|
{
"page_id": 3214453,
"source": null,
"title": "Moisture vapor transmission rate"
}
|
measured, controlled and recorded with the result, and the thickness of the sample should be the same. An MVTR result without specifying these conditions is almost meaningless. Certainly no two results should be compared unless the conditions are known. For example, the effect of temperature on the permeability can be as high as 10% per °C, making it possible that MVTR results achieved at 23°C and 37°C can differ by a factor 4. The most common international unit for the MVTR is g/m2/day, or "metric perm". In the USA, g/100in2/day is also in use, which is 0.064516 (approximately 1/15) of the value of g/m2/day units. Typical rates in aluminium foil laminates may be as low as 0.001 g/m2/day, whereas the rate in fabrics can measure up to several thousand g/m2/day. Often, barrier testing is conducted on a sheet of material. Calculations based on that can be useful when designing completed structures, clothing, and packages. Seams, creases, access points, and heat seals are critical to end-use performance. For example, the glass of a bottle may have an effective total barrier, but the screw cap closure and the closure liner might not. Performance verification and validation of complete containers, structures, or irregular objects is often recommended. For the special case of OLEDs, where the levels of allowed permeation are in the 10−6 g/m2/day level, the methods preferred exploit an oxidation of a metal upon the exposure to water. == See also == Adsorption Carbon dioxide transmission rate Moisture sorption isotherm Oxygen transmission rate Packaging Permeation Shelf life Vapor barrier == Further reading == Bell, L.N., and Labuza, T.P. 2000. "Practical Aspects of Moisture Sorption Isotherm Measurement and Use". 2nd Edition AACC Egan Press, Egan, MN Yam, K.L., "Encyclopedia of Packaging Technology", John Wiley & Sons, 2009, ISBN 978-0-470-08704-6 Massey, L K, "Permeability
|
{
"page_id": 3214453,
"source": null,
"title": "Moisture vapor transmission rate"
}
|
Properties of Plastics and Elastomers", 2003, Andrew Publishing, ISBN 978-1-884207-97-6 === USP Regulatory Standards === For drugs sold in the United States, the U.S. Pharmacopeia (USP) defines standards for moisture transmission of drug packaging. USP <671> === ASTM Standards === ASTM D1434 - Standard Test Method for Determining Gas Permeability Characteristics of Plastic Film and Sheeting ASTM D3079 - Standard Test Method for Water Vapor Transmission of Flexible Heat-Sealed Packages for Dry Products ASTM D4279 - Standard Test Methods for Water Vapor Transmission of Shipping Containers-Constant and Cycle Methods ASTM D7709 - Standard Test Methods for Measuring Water Vapor Transmission Rate (WVTR) of Pharmaceutical Bottles and Blisters ASTM E96 - Standard Test Methods for Water Vapor Transmission of Materials ASTM E398 - Standard Test Method for Water Vapor Transmission Rate of Sheet Materials Using Dynamic Relative Humidity Measurement ASTM F1249 - Standard Test Method for Water Vapor Transmission Rate Through Plastic Film and Sheeting Using a Modulated Infrared Sensor ASTM F2298- Standard Test Methods for Water Vapor Diffusion Resistance and Air Flow Resistance of Clothing Materials Using the Dynamic Moisture Permeation Cell == References ==
|
{
"page_id": 3214453,
"source": null,
"title": "Moisture vapor transmission rate"
}
|
Soredia are common reproductive structures of lichens. Lichens reproduce asexually by employing simple fragmentation and production of soredia and isidia. Soredia are powdery propagules composed of fungal hyphae wrapped around cyanobacteria or green algae. These can be either scattered diffusely across the surface of the lichen's thallus, or produced in localized structures called soralia. Fungal hyphae make up the basic body structure of a lichen. The soredia are released through openings in the upper cortex of the lichen structure. After their release, the soredia disperse to establish the lichen in a new location. == References ==
|
{
"page_id": 14617718,
"source": null,
"title": "Soredium"
}
|
Australia's diverse and often attractive flora has been depicted on numerous Australian stamp issues: Acacia baileyana – 1978 Acacia coriacea – 2002 Acacia dealbata (?) – 1982 Acacia melanoxylon – 1996 Acacia pycnantha – 1959, 1979, 1990 Acmena smithii – 2002 Actinodium cunninghamii – 2005 Actinotus helianthi – 1959 Adansonia gregorii – 2005 Anigozanthos 'Bush Tango' – 2003 Anigozanthos manglesii – 1962, 1968, 2006 Armillaria luteobubalina fungus – 1981 Banksia integrifolia – 2000 Banksia prionotes (?) – 1996 Banksia serrata – 1960, 1986 Barringtonia calyptrata – 2001 Blandfordia grandiflora – 1960, 1967 Blandfordia punicea – 2007 Brachychiton acerifolius – 1978 Callistemon glaucus – 2000 Callistemon teretifolius – 1975 Caleana major – 1986 Caltha introloba – 1986 Calytrix carinata – 2002 Celmisia asteliifolia – 1986 Cochlospermum gillivraei – 2001 Coprinus comatus fungus – 1981 Correa reflexa – 1986, 1999 Cortinarius austrovenetus fungus – 1981 Cortinarius cinnabarinus fungus – 1981 Dendrobium nindii – 1986, 2003 Dendrobium phalaenopsis – 1968, 1998 Dicksonia antarctica – 1996 Dillenia alata – 1986 Diuris magnifica – 2006 Elythranthera emarginata – 1986 Epacris impressa – 1968 Eucalyptus caesia – 1982 Eucalyptus calophylla 'Rosea' – 1982 Eucalyptus camaldulensis – 1974 Eucalyptus diversicolor – 2005 Eucalyptus ficifolia – 1982 Eucalyptus forrestiana – 1982 Eucalyptus globulus – 1968, 1982 Eucalyptus grossa – 2005 Eucalyptus pauciflora – 2005 Euschemon rafflesia – 1983 Eucalyptus papuana – 1978, 1993, 2002 Eucalyptus regnans – 1996 Eucalyptus sp. – 1985 Ficus macrophylla – 2005 Gossypium sturtianum – 1971, 1978, 2007 Grevillea juncifolia – 2002 Grevillea mucronulata – 2007 Grevillea 'Superb' – 2003 Hakea laurina – 2006 Hardenbergia violacea – 2000 Helichrysum thomsonii – 1975 Helipterum albicans – 1986 Hibbertia scandens – 1999 Hibiscus meraukensis – 1986 Ipomoea pes-caprae ssp. brasiliensis – 1999 Leucochrysum albicans – 1986 Microseros lanceolata – 2002 Nelumbo nucifera – 2002 Nymphaea immutabilis
|
{
"page_id": 3345526,
"source": null,
"title": "List of flora on stamps of Australia"
}
|
– 2002 Phalaenopsis rosenstromii – 1998 Phebalium whitei – 2007 Swainsona formosa – 1968, 1971, 2005 Santalum acuminatum – 2002 Telopea speciosissima – 1959, 1968, 2006 Thelymitra variegata – 1986 Thysanothus tuberosus – 2005 Wahlenbergia gloriosa – 1986 Wahlenbergia stricta – 1999 Wollemia nobilis – 2005 Xanthorrhoea australis – 1978 == See also == List of people on stamps of Australia List of butterflies on stamps of Australia == References == Australian Plants on Postage Stamps by Australian National Botanic Gardens Australian Stamp Bulletin No. 280 June - August 2005 Australian Stamp Bulletin No. 282 January - February 2006 Australian Stamp Bulletin No. 286 January - March 2007
|
{
"page_id": 3345526,
"source": null,
"title": "List of flora on stamps of Australia"
}
|
The Forouhi–Bloomer model is a mathematical formula for the frequency dependence of the complex-valued refractive index. The model can be used to fit the refractive index of amorphous and crystalline semiconductor and dielectric materials at energies near and greater than their optical band gap. The dispersion relation bears the names of Rahim Forouhi and Iris Bloomer, who created the model and interpreted the physical significance of its parameters. The model is aphysical due to its incorrect asymptotic behavior and non-Hermitian character. These shortcomings inspired modified versions of the model as well as development of the Tauc–Lorentz model. == Mathematical formulation == The complex refractive index is given by n ~ ( E ) = n ( E ) + i κ ( E ) {\displaystyle {\tilde {n}}(E)=n(E)+i\kappa (E)} where n {\displaystyle n} is the real component of the complex refractive index, commonly called the refractive index, κ {\displaystyle \kappa } is the imaginary component of the complex refractive index, commonly called the extinction coefficient, E {\displaystyle E} is the photon energy (related to the angular frequency by E = ℏ ω {\displaystyle E=\hbar \omega } ). The real and imaginary components of the refractive index are related to one another through the Kramers-Kronig relations. Forouhi and Bloomer derived a formula for κ ( E ) {\displaystyle \kappa (E)} for amorphous materials. The formula and complementary Kramers–Kronig integral are given by κ ( E ) = A ( E − E g ) 2 E 2 − B E + C {\displaystyle \kappa (E)={\frac {A\left(E-E_{g}\right)^{2}}{E^{2}-BE+C}}} n ( E ) = n ∞ + 1 π P ∫ − ∞ ∞ κ ( ξ ) − κ ∞ ξ − E d ξ {\displaystyle n(E)=n_{\infty }+{\frac {1}{\pi }}{\mathcal {P}}\int _{-\infty }^{\infty }{\frac {\kappa (\xi )-\kappa _{\infty }}{\xi -E}}d\xi } where E g
|
{
"page_id": 69209212,
"source": null,
"title": "Forouhi–Bloomer model"
}
|
{\displaystyle E_{g}} is the bandgap of the material, A {\displaystyle A} , B {\displaystyle B} , C {\displaystyle C} , and n ∞ {\displaystyle n_{\infty }} are fitting parameters, P {\displaystyle {\mathcal {P}}} denotes the Cauchy principal value, κ ∞ = lim E → ∞ κ ( E ) = A {\displaystyle \kappa _{\infty }=\lim _{E\rightarrow \infty }\kappa (E)=A} . A {\displaystyle A} , B {\displaystyle B} , and C {\displaystyle C} are subject to the constraints A > 0 {\displaystyle A>0} , B > 0 {\displaystyle B>0} , C > 0 {\displaystyle C>0} , and 4 C − B 2 > 0 {\displaystyle 4C-B^{2}>0} . Evaluating the Kramers-Kronig integral, n ( E ) = n ∞ + B 0 E + C 0 E 2 − B E + C {\displaystyle n(E)=n_{\infty }+{\frac {B_{0}E+C_{0}}{E^{2}-BE+C}}} where Q = 1 2 4 C − B 2 {\displaystyle Q={\frac {1}{2}}{\sqrt {4C-B^{2}}}} , B 0 = A Q ( − 1 2 B 2 + E g B − E g 2 + C ) {\displaystyle B_{0}={\frac {A}{Q}}\left(-{\frac {1}{2}}B^{2}+E_{g}B-E_{g}^{2}+C\right)} , C 0 = A Q ( 1 2 B ( E g 2 + C ) − 2 E g C ) {\displaystyle C_{0}={\frac {A}{Q}}\left({\frac {1}{2}}B\left(E_{g}^{2}+C\right)-2E_{g}C\right)} . The Forouhi–Bloomer model for crystalline materials is similar to that of amorphous materials. The formulas for n ( E ) {\displaystyle n(E)} and κ ( E ) {\displaystyle \kappa (E)} are given by n ( E ) = n ∞ + ∑ j B 0 , j E + C 0 , j E 2 − B j E + C j {\displaystyle n(E)=n_{\infty }+\sum _{j}{\frac {B_{0,j}E+C_{0,j}}{E^{2}-B_{j}E+C_{j}}}} . κ ( E ) = ( E − E g ) 2 ∑ j A j E 2 − B j E + C j {\displaystyle \kappa (E)=\left(E-E_{g}\right)^{2}\sum
|
{
"page_id": 69209212,
"source": null,
"title": "Forouhi–Bloomer model"
}
|
_{j}{\frac {A_{j}}{E^{2}-B_{j}E+C_{j}}}} . where all variables are defined similarly to the amorphous case, but with unique values for each value of the summation index j {\displaystyle j} . Thus, the model for amorphous materials is a special case of the model for crystalline materials when the sum is over a single term only. == References == == See also == Cauchy equation Sellmeier equation Lorentz oscillator model Tauc–Lorentz model Brendel–Bormann oscillator model
|
{
"page_id": 69209212,
"source": null,
"title": "Forouhi–Bloomer model"
}
|
Even restricting the discussion to physics, scientists do not have a unique definition of what matter is. In the currently known particle physics, summarised by the standard model of elementary particles and interactions, it is possible to distinguish in an absolute sense particles of matter and particles of antimatter. This is particularly easy for those particles that carry electric charge, such as electrons, protons or quarks, while the distinction is more subtle in the case of neutrinos, fundamental elementary particles that do not carry electric charge. In the standard model, it is not possible to create a net amount of matter particles—or more precisely, it is not possible to change the net number of leptons or of quarks in any perturbative reaction among particles. This remark is consistent with all existing observations. However, similar processes are not considered to be impossible and are expected in other models of the elementary particles, that extend the standard model. They are necessary in speculative theories that aim to explain the cosmic excess of matter over antimatter, such as leptogenesis and baryogenesis. They could even manifest themselves in laboratory as proton decay or as creations of electrons in the so-called neutrinoless double beta decay. The latter case occurs if the neutrinos are Majorana particles, being at the same time matter and antimatter, according to the definition given just above. In a wider sense, one can use the word matter simply to refer to fermions. In this sense, matter and antimatter particles (such as an electron and a positron) are identified beforehand. The process inverse to particle annihilation can be called matter creation; more precisely, we are considering here the process obtained under time reversal of the annihilation process. This process is also known as pair production, and can be described as the conversion of
|
{
"page_id": 2362494,
"source": null,
"title": "Matter creation"
}
|
light particles (i.e., photons) into one or more massive particles. The most common and well-studied case is the one where two photons convert into an electron–positron pair. == Photon pair production == Because of momentum conservation laws, the creation of a pair of fermions (matter particles) out of a single photon cannot occur. However, matter creation is allowed by these laws when in the presence of another particle (another boson, or even a fermion) which can share the primary photon's momentum. Thus, matter can be created out of two photons. The law of conservation of energy sets a minimum photon energy required for the creation of a pair of fermions: this threshold energy must be greater than the total rest energy of the fermions created. To create an electron-positron pair, the total energy of the photons, in the rest frame, must be at least 2mec2 = 2 × 0.511 MeV = 1.022 MeV (me is the mass of one electron and c is the speed of light in vacuum), an energy value that corresponds to soft gamma ray photons. The creation of a much more massive pair, like a proton and antiproton, requires photons with energy of more than 1.88 GeV (hard gamma ray photons). The first published calculations of the rate of e+–e− pair production in photon-photon collisions were done by Lev Landau in 1934. It was predicted that the process of e+–e− pair creation (via collisions of photons) dominates in collision of ultra-relativistic charged particles—because those photons are radiated in narrow cones along the direction of motion of the original particle, greatly increasing photon flux. In high-energy particle colliders, matter creation events have yielded a wide variety of exotic heavy particles precipitating out of colliding photon jets (see two-photon physics). Currently, two-photon physics studies creation of various fermion
|
{
"page_id": 2362494,
"source": null,
"title": "Matter creation"
}
|
pairs both theoretically and experimentally (using particle accelerators, air showers, radioactive isotopes, etc.). It is possible to create all fundamental particles in the standard model, including quarks, leptons and bosons using photons of varying energies above some minimum threshold, whether directly (by pair production), or by decay of the intermediate particle (such as a W− boson decaying to form an electron and an electron-antineutrino). As shown above, to produce ordinary baryonic matter out of a photon gas, this gas must not only have a very high photon density, but also be very hot – the energy (temperature) of photons must obviously exceed the rest mass energy of the given matter particle pair. The threshold temperature for production of electrons is about 1010 K, 1013 K for protons and neutrons, etc. According to the Big Bang theory, in the early universe, mass-less photons and massive fermions would inter-convert freely. As the photon gas expanded and cooled, some fermions would be left over (in extremely small amounts ~10−10) because low energy photons could no longer break them apart. Those left-over fermions would have become the matter we see today in the universe around us. == See also == Annihilation Available energy Pair production Schwinger limit == References ==
|
{
"page_id": 2362494,
"source": null,
"title": "Matter creation"
}
|
Anthropometry ( , from Ancient Greek ἄνθρωπος (ánthrōpos) 'human' and μέτρον (métron) 'measure') refers to the measurement of the human individual. An early tool of physical anthropology, it has been used for identification, for the purposes of understanding human physical variation, in paleoanthropology and in various attempts to correlate physical with racial and psychological traits. Anthropometry involves the systematic measurement of the physical properties of the human body, primarily dimensional descriptors of body size and shape. Since commonly used methods and approaches in analysing living standards were not helpful enough, the anthropometric history became very useful for historians in answering questions that interested them. Today, anthropometry plays an important role in industrial design, clothing design, ergonomics and architecture where statistical data about the distribution of body dimensions in the population are used to optimize products. Changes in lifestyles, nutrition, and ethnic composition of populations lead to changes in the distribution of body dimensions (e.g. the rise in obesity) and require regular updating of anthropometric data collections. == History == The history of anthropometry includes and spans various concepts, both scientific and pseudoscientific, such as craniometry, paleoanthropology, biological anthropology, phrenology, physiognomy, forensics, criminology, phylogeography, human origins, and cranio-facial description, as well as correlations between various anthropometrics and personal identity, mental typology, personality, cranial vault and brain size, and other factors. At various times in history, applications of anthropometry have ranged from accurate scientific description and epidemiological analysis to rationales for eugenics and overtly racist social movements. One of its misuses was the discredited pseudoscience, phrenology. == Individual variation == === Auxologic === Auxologic is a broad term covering the study of all aspects of human physical growth. ==== Height ==== Human height varies greatly between individuals and across populations for a variety of complex biological, genetic, and environmental factors, among others.
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Due to methodological and practical problems, its measurement is also subject to considerable error in statistical sampling. The average height in genetically and environmentally homogeneous populations is often proportional across a large number of individuals. Exceptional height variation (around 20% deviation from a population's average) within such a population is sometimes due to gigantism or dwarfism, which are caused by specific genes or endocrine abnormalities. It is important to note that a great degree of variation occurs between even the most 'common' bodies (66% of the population), and as such no person can be considered 'average'. In the most extreme population comparisons, for example, the average female height in Bolivia is 142.2 cm (4 ft 8.0 in) while the average male height in the Dinaric Alps is 185.6 cm (6 ft 1.1 in), an average difference of 43.4 cm (1 ft 5.1 in). Similarly, the shortest and tallest of individuals, Chandra Bahadur Dangi and Robert Wadlow, have ranged from 53–272 cm (1 ft 9 in – 8 ft 11 in), respectively. The age range where most females stop growing is 15–18 years and the age range where most males stop growing is 18–21 years. ==== Weight ==== Human weight varies extensively both individually and across populations, with the most extreme documented examples of adults being Lucia Zarate who weighed 2.1 kg (4.7 lb), and Jon Brower Minnoch who weighed 640 kg (1,400 lb), and with population extremes ranging from 49.6 kg (109.3 lb) in Bangladesh to 87.4 kg (192.7 lb) in Micronesia. ==== Organs ==== Adult brain size varies from 974.9 cm3 (59.49 cu in) to 1,498.1 cm3 (91.42 cu in) in females and 1,052.9 cm3 (64.25 cu in) to 1,498.5 cm3 (91.44 cu in) in males, with the average being 1,130 cm3 (69 cu in) and 1,260 cm3 (77
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cu in), respectively. The right cerebral hemisphere is typically larger than the left, whereas the cerebellar hemispheres are typically of more similar size. Size of the human stomach varies significantly in adults, with one study showing volumes ranging from 520 cm3 (32 cu in) to 1,536 cm3 (93.7 cu in) and weights ranging from 77 grams (2.7 oz) to 453 grams (16.0 oz). Male and female genitalia exhibit considerable individual variation, with penis size differing substantially and vaginal size differing significantly in healthy adults. === Aesthetic === Human beauty and physical attractiveness have been preoccupations throughout history which often intersect with anthropometric standards. Cosmetology, facial symmetry, and waist–hip ratio are three such examples where measurements are commonly thought to be fundamental. == Evolutionary science == Anthropometric studies today are conducted to investigate the evolutionary significance of differences in body proportion between populations whose ancestors lived in different environments. Human populations exhibit climatic variation patterns similar to those of other large-bodied mammals, following Bergmann's rule, which states that individuals in cold climates will tend to be larger than ones in warm climates, and Allen's rule, which states that individuals in cold climates will tend to have shorter, stubbier limbs than those in warm climates. On a microevolutionary level, anthropologists use anthropometric variation to reconstruct small-scale population history. For instance, John Relethford's studies of early 20th-century anthropometric data from Ireland show that the geographical patterning of body proportions still exhibits traces of the invasions by the English and Norse centuries ago. Similarly, anthropometric indices, namely comparison of the human stature was used to illustrate anthropometric trends. This study was conducted by Jörg Baten and Sandew Hira and was based on the anthropological founds that human height is predetermined by the quality of the nutrition, which used to be higher in the more
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developed countries. The research was based on the datasets for Southern Chinese contract migrants who were sent to Suriname and Indonesia and included 13,000 individuals. == Measuring instruments == === 3D body scanners === Today anthropometry can be performed with three-dimensional scanners. A global collaborative study to examine the uses of three-dimensional scanners for health care was launched in March 2007. The Body Benchmark Study will investigate the use of three-dimensional scanners to calculate volumes and segmental volumes of an individual body scan. The aim is to establish whether the Body Volume Index has the potential to be used as a long-term computer-based anthropometric measurement for health care. In 2001 the UK conducted the largest sizing survey to date using scanners. Since then several national surveys have followed in the UK's pioneering steps, notably SizeUSA, SizeMexico, and SizeThailand, the latter still ongoing. SizeUK showed that the nation had become taller and heavier but not as much as expected. Since 1951, when the last women's survey had taken place, the average weight for women had gone up from 62 to 65 kg. However, recent research has shown that posture of the participant significantly influences the measurements taken, the precision of 3D body scanner may or may not be high enough for industry tolerances, and measurements taken may or may not be relevant to all applications (e.g. garment construction). Despite these current limitations, 3D body scanning has been suggested as a replacement for body measurement prediction technologies which (despite the great appeal) have yet to be as reliable as real human data. === Baropodographic === Baropodographic devices fall into two main categories: (i) floor-based, and (ii) in-shoe. The underlying technology is diverse, ranging from piezoelectric sensor arrays to light refraction, but the ultimate form of the data generated by all modern technologies
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is either a 2D image or a 2D image time series of the pressures acting under the plantar surface of the foot. From these data other variables may be calculated (see data analysis.) The spatial and temporal resolutions of the images generated by commercial pedobarographic systems range from approximately 3 to 10 mm and 25 to 500 Hz, respectively. Sensor technology limits finer resolution. Such resolutions yield a contact area of approximately 500 sensors (for a typical adult human foot with surface area of approximately 100 cm2). For a stance phase duration of approximately 0.6 seconds during normal walking, approximately 150,000 pressure values, depending on the hardware specifications, are recorded for each step. === Neuroimaging === Direct measurements involve examinations of brains from corpses, or more recently, imaging techniques such as MRI, which can be used on living persons. Such measurements are used in research on neuroscience and intelligence. Brain volume data and other craniometric data are used in mainstream science to compare modern-day animal species and to analyze the evolution of the human species in archeology. == Epidemiology and medical anthropology == Anthropometric measurements also have uses in epidemiology and medical anthropology, for example in helping to determine the relationship between various body measurements (height, weight, percentage body fat, etc.) and medical outcomes. Anthropometric measurements are frequently used to diagnose malnutrition in resource-poor clinical settings. == Forensics and criminology == Forensic anthropologists study the human skeleton in a legal setting. A forensic anthropologist can assist in the identification of a decedent through various skeletal analyses that produce a biological profile. Forensic anthropologists use the Fordisc program to help in the interpretation of craniofacial measurements in regards to ancestry determination. One part of a biological profile is a person's ancestral affinity. People with significant European or Middle Eastern ancestry generally
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have little to no prognathism; a relatively long and narrow face; a prominent brow ridge that protrudes forward from the forehead; a narrow, tear-shaped nasal cavity; a "silled" nasal aperture; tower-shaped nasal bones; a triangular-shaped palate; and an angular and sloping eye orbit shape. People with considerable African ancestry typically have a broad and round nasal cavity; no dam or nasal sill; Quonset hut-shaped nasal bones; notable facial projection in the jaw and mouth area (prognathism); a rectangular-shaped palate; and a square or rectangular eye orbit shape. A relatively small prognathism often characterizes people with considerable East Asian ancestry; no nasal sill or dam; an oval-shaped nasal cavity; tent-shaped nasal bones; a horseshoe-shaped palate; and a rounded and non-sloping eye orbit shape. Many of these characteristics are only a matter of frequency among those of particular ancestries: their presence or absence of one or more does not automatically classify an individual into an ancestral group. == Ergonomics == Ergonomics professionals apply an understanding of human factors to the design of equipment, systems and working methods to improve comfort, health, safety, and productivity. This includes physical ergonomics in relation to human anatomy, physiological and bio mechanical characteristics; cognitive ergonomics in relation to perception, memory, reasoning, motor response including human–computer interaction, mental workloads, decision making, skilled performance, human reliability, work stress, training, and user experiences; organizational ergonomics in relation to metrics of communication, crew resource management, work design, schedules, teamwork, participation, community, cooperative work, new work programs, virtual organizations, and telework; environmental ergonomics in relation to human metrics affected by climate, temperature, pressure, vibration, and light; visual ergonomics; and others. == Biometrics == Biometrics refers to the identification of humans by their characteristics or traits. Biometrics is used in computer science as a form of identification and access control. It is also
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used to identify individuals in groups that are under surveillance. Biometric identifiers are the distinctive, measurable characteristics used to label and describe individuals. Biometric identifiers are often categorized as physiological versus behavioral characteristics. Subclasses include dermatoglyphics and soft biometrics. == United States military research == The US Military has conducted over 40 anthropometric surveys of U.S. Military personnel between 1945 and 1988, including the 1988 Army Anthropometric Survey (ANSUR) of men and women with its 240 measures. Statistical data from these surveys encompasses over 75,000 individuals. == Civilian American and European Surface Anthropometry Resource Project == CAESAR began in 1997 as a partnership between government (represented by the US Air Force and NATO) and industry (represented by SAE International) to collect and organize the most extensive sampling of consumer body measurements for comparison. The project collected and organized data on 2,400 U.S. & Canadian and 2,000 European civilians and a database was developed. This database records the anthropometric variability of men and women, aged 18–65, of various weights, ethnic groups, gender, geographic regions, and socio-economic status. The study was conducted from April 1998 to early 2000 and included three scans per person in a standing pose, full-coverage pose and relaxed seating pose. Data collection methods were standardized and documented so that the database can be consistently expanded and updated. High-resolution measurements of body surfaces were made using 3D Surface Anthropometry. This technology can capture hundreds of thousands of points in three dimensions on the human body surface in a few seconds. It has many advantages over the old measurement system using tape measures, anthropometers, and other similar instruments. It provides detail about the surface shape as well as 3D locations of measurements relative to each other and enables easy transfer to Computer-Aided Design (CAD) or Manufacturing (CAM) tools. The resulting
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scan is independent of the measurer, making it easier to standardize. Automatic landmark recognition (ALR) technology was used to extract anatomical landmarks from the 3D body scans automatically. Eighty landmarks were placed on each subject. More than 100 univariate measures were provided, over 60 from the scan and approximately 40 using traditional measurements. Demographic data such as age, ethnic group, gender, geographic region, education level, and present occupation, family income and more were also captured. == Fashion design == Scientists working for private companies and government agencies conduct anthropometric studies to determine a range of sizes for clothing and other items. For just one instance, measurements of the foot are used in the manufacture and sale of footwear: measurement devices may be used either to determine a retail shoe size directly (e.g. the Brannock Device) or to determine the detailed dimensions of the foot for custom manufacture (e.g. ALINEr). == See also == == References == == Further reading == Anthropometric Survey of Army Personnel: Methods and Summary Statistics 1988 Archived 2022-06-21 at the Wayback Machine ISO 7250: Basic human body measurements for technological design, International Organization for Standardization, 1998. ISO 8559: Garment construction and anthropometric surveys — Body dimensions, International Organization for Standardization, 1989. ISO 15535: General requirements for establishing anthropometric databases, International Organization for Standardization, 2000. ISO 15537: Principles for selecting and using test persons for testing anthropometric aspects of industrial products and designs, International Organization for Standardization, 2003. ISO 20685: 3-D scanning methodologies for internationally compatible anthropometric databases, International Organization for Standardization, 2005. Pheasant, Stephen (1986). Bodyspace : anthropometry, ergonomics, and design. London; Philadelphia: Taylor & Francis. ISBN 978-0-85066-352-5. (A classic review of human body sizes.) Pheasant, S.; Haslegrave, C.M. (2006). Bodyspace: Anthropometry, Ergonomics and the Design of Work (3rd ed.). CRC Press. ISBN 9780415285209. Redman, Samuel
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(2016). Bone Rooms: From Scientific Racism to Human Prehistory in Museums. Cambridge: Harvard University Press. ISBN 9780674660410. == External links == Anthropometry at the Centers for Disease Control and Prevention Anthropometry and Biomechanics at NASA Anthropometry data at faculty of Industrial Design Engineering at Delft University of Technology Manual for Obtaining Anthropometric Measurements Free Full Text Prepared for the US Access Board: Anthropometry of Wheeled Mobility Project Report Free Full Text Civilian American and European Surface Anthropometry Resource Project—CAESAR at SAE International
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Major actinides is a term used in the nuclear power industry that refers to the isotopes of plutonium (239 Pu) uranium (235 U, 238 U) and thorium (232 Th) present in nuclear fuel, as opposed to the minor actinides neptunium, americium, curium, berkelium, and californium, including other isotopes of uranium and plutonium and other actinides. == References ==
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"title": "Major actinide"
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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" simply 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 calcium fluoride. Cations of transition metals able to take multiple charges are labeled with Roman numerals in parentheses to indicate their charge. For example, Cu+ is copper(I), Cu2+ is copper(II). An older, deprecated notation is to append -ous or -ic to the root of the Latin name to name ions with a lesser or greater charge. Under this naming convention, Cu+ is cuprous and Cu2+ is cupric. For naming metal complexes see
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the page on complex (chemistry). Oxyanions (polyatomic anions containing oxygen) are named with -ite or -ate, for a lesser or greater quantity of oxygen, respectively. For example, NO−2 is nitrite, while NO−3 is nitrate. If four oxyanions are possible, the prefixes hypo- and per- are used: hypochlorite is ClO−, perchlorate is ClO−4. The prefix bi- is a deprecated way of indicating the presence of a single hydrogen ion, as in "sodium bicarbonate" (NaHCO3). The modern method specifically names the hydrogen atom. Thus, NaHCO3 would be pronounced sodium hydrogen carbonate. Positively charged ions are called cations and negatively charged ions are called anions. The cation is always named first. Ions can be metals, non-metals or polyatomic ions. Therefore, the name of the metal or positive polyatomic ion is followed by the name of the non-metal or negative polyatomic ion. The positive ion retains its element name whereas for a single non-metal anion the ending is changed to -ide. Example: sodium chloride, potassium oxide, or calcium carbonate. When the metal has more than one possible ionic charge or oxidation number the name becomes ambiguous. In these cases the oxidation number (the same as the charge) of the metal ion is represented by a Roman numeral in parentheses immediately following the metal ion name. For example, in uranium(VI) fluoride the oxidation number of uranium is 6. Another example is the iron oxides. FeO is iron(II) oxide and Fe2O3 is iron(III) oxide. An older system used prefixes and suffixes to indicate the oxidation number, according to the following scheme: Thus the four oxyacids of chlorine are called hypochlorous acid (HOCl), chlorous acid (HOClO), chloric acid (HOClO2) and perchloric acid (HOClO3), and their respective conjugate bases are hypochlorite, chlorite, chlorate and perchlorate ions. This system has partially fallen out of use, but survives in the
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common names of many chemical compounds: the modern literature contains few references to "ferric chloride" (instead calling it "iron(III) chloride"), but names like "potassium permanganate" (instead of "potassium manganate(VII)") and "sulfuric acid" abound. == Traditional naming == === Simple ionic compounds === An ionic compound is named by its cation followed by its anion. See polyatomic ion for a list of possible ions. For cations that take on multiple charges, the charge is written using Roman numerals in parentheses immediately following the element name. For example, Cu(NO3)2 is copper(II) nitrate, because the charge of two nitrate ions (NO−3) is 2 × −1 = −2, and since the net charge of the ionic compound must be zero, the Cu ion has a 2+ charge. This compound is therefore copper(II) nitrate. In the case of cations with a +4 oxidation state, the only acceptable format for the Roman numeral 4 is IV and not IIII. The Roman numerals in fact show the oxidation number, but in simple ionic compounds (i.e., not metal complexes) this will always equal the ionic charge on the metal. For a simple overview see [1] Archived 2008-10-16 at the Wayback Machine, for more details see selected pages from IUPAC rules for naming inorganic compounds Archived 2016-03-03 at the Wayback Machine. ==== List of common ion names ==== Monatomic anions: Cl− chloride S2− sulfide P3− phosphide Polyatomic ions: NH+4 ammonium H3O+ hydronium NO−3 nitrate NO−2 nitrite ClO− hypochlorite ClO−2 chlorite ClO−3 chlorate ClO−4 perchlorate SO2−3 sulfite SO2−4 sulfate S2O2–3 thiosulfate HSO−3 hydrogen sulfite (or bisulfite) HCO−3 hydrogen carbonate (or bicarbonate) CO2−3 carbonate PO3−4 phosphate HPO2−4 hydrogen phosphate H2PO−4 dihydrogen phosphate CrO2−4 chromate Cr2O2−7 dichromate BO3−3 borate AsO3−4 arsenate C2O2−4 oxalate CN− cyanide SCN− thiocyanate MnO−4 permanganate === Hydrates === Hydrates are ionic compounds that have absorbed water. They are
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named as the ionic compound followed by a numerical prefix and -hydrate. The numerical prefixes used are listed below (see IUPAC numerical multiplier): mono- di- tri- tetra- penta- hexa- hepta- octa- nona- deca- For example, CuSO4·5H2O is "copper(II) sulfate pentahydrate". === Molecular compounds === Inorganic molecular compounds are named with a prefix (see list above) before each element. The more electronegative element is written last and with an -ide suffix. For example, H2O (water) can be called dihydrogen monoxide. Organic molecules do not follow this rule. In addition, the prefix mono- is not used with the first element; for example, SO2 is sulfur dioxide, not "monosulfur dioxide". Sometimes prefixes are shortened when the ending vowel of the prefix "conflicts" with a starting vowel in the compound. This makes the name easier to pronounce; for example, CO is "carbon monoxide" (as opposed to "monooxide"). ==== Common exceptions ==== The "a" of the penta- prefix is not dropped before a vowel. As the IUPAC Red Book 2005 page 69 states, "The final vowels of multiplicative prefixes should not be elided (although 'monoxide', rather than 'monooxide', is an allowed exception because of general usage)." There are a number of exceptions and special cases that violate the above rules. Sometimes the prefix is left off the initial atom: I2O5 is known as iodine pentaoxide, but it should be called diiodine pentaoxide. N2O3 is called nitrogen sesquioxide (sesqui- means 1+1⁄2). The main oxide of phosphorus is called phosphorus pentaoxide. It should actually be diphosphorus pentaoxide, but it is assumed that there are two phosphorus atoms (P2O5), as they are needed in order to balance the oxidation numbers of the five oxygen atoms. However, people have known for years that the real form of the molecule is P4O10, not P2O5, yet it is not normally called
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tetraphosphorus decaoxide. In writing formulas, ammonia is NH3 even though nitrogen is more electronegative (in line with the convention used by IUPAC as detailed in Table VI of the red book). Likewise, methane is written as CH4 even though carbon is more electronegative (Hill system). == Nomenclature of Inorganic Chemistry == Nomenclature of Inorganic Chemistry, commonly referred to by chemists as the Red Book, is a collection of recommendations on IUPAC nomenclature, published at irregular intervals by the IUPAC. The last full edition was published in 2005, in both paper and electronic versions. == See also == IUPAC nomenclature IUPAC nomenclature of organic chemistry List of inorganic compounds Water of crystallization IUPAC nomenclature of inorganic chemistry 2005 (the Red Book) Nomenclature of Organic Chemistry (the Blue Book) Quantities, Units and Symbols in Physical Chemistry (the Green Book) Compendium of Chemical Terminology (the Gold Book) Compendium of Analytical Nomenclature (the Orange Book) == References == == External links == IUPAC website - Nomenclature IUPAC (old site) Red Book IUPAC (old site) Red Book - PDF (2005 Recommendations) Recommendations 2000-Red Book II (incomplete) IUPAC (old site) Nomenclature Books Series (commonly known as the "Colour Books") ChemTeam Highschool Tutorial
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Kugel–Khomskii coupling describes a coupling between the spin and orbital degrees of freedom in a solid; it is named after the Russian physicists Kliment I. Kugel (Климент Ильич Кугель) and Daniel I. Khomskii (Daniil I. Khomskii, Даниил Ильич Хомский). The Hamiltonian used is: H = t 2 U ∑ ⟨ i , j ⟩ [ 4 ( S i → ⋅ S j → ) ( τ i α − 1 2 ) ( τ j α − 1 2 ) + ( τ i α + 1 2 ) ( τ j α + 1 2 ) − 1 ] . {\displaystyle H={\frac {t^{2}}{U}}\sum _{\langle i,j\rangle }\left[4\left({\overrightarrow {S_{i}}}\cdot {\overrightarrow {S_{j}}}\right)\left(\tau _{i}^{\alpha }-{\frac {1}{2}}\right)\left(\tau _{j}^{\alpha }-{\frac {1}{2}}\right)+\left(\tau _{i}^{\alpha }+{\frac {1}{2}}\right)\left(\tau _{j}^{\alpha }+{\frac {1}{2}}\right)-1\right].} == References == G. Khaliullin and V. Oudovenko (1 Dec 1997). "Spin and orbital excitation spectrum in the Kugel-Khomskii model" (PDF). Physical Review B. 56 (22): R14243 – R14246. arXiv:cond-mat/9710070. Bibcode:1997PhRvB..5614243K. doi:10.1103/PhysRevB.56.R14243. S2CID 119360845. Archived from the original (PDF) on 19 August 2011. K. I. Kugel and D. I. Khomskii (1982). "The Jahn-Teller effect and magnetism: transition metal compounds". Soviet Physics Uspekhi. 25 (4): 231. doi:10.1070/PU1982v025n04ABEH004537.
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An embedded lens is a gravitational lens that consists of a concentration of mass enclosed by (embedded in) a relative void in the surrounding distribution of matter: both the mass and the presence of a void surrounding it will affect the path of light passing through the vicinity. This is in contrast with the simpler, more familiar gravitational lens effect, in which there is no surrounding void. While any shape and arrangement of increased and decreased mass densities will cause gravitational lensing, an ideal embedded lens would be spherical and have an internal mass density matching that of the surrounding region of space. The gravitational influence of an embedded lens differs from that of a simple gravitational lens: light rays will be bent by different angles and embedded lenses of a cosmologically significant scale would affect the spatial evolution (expansion) of the universe. In a region of homogeneous density, a spherical embedded lens would correspond to the symmetric concentration of a spherical locality's mass into a smaller sphere (or a point) at its center. For a cosmological lens, if the universe has a non-vanishing cosmological constant Λ, then Λ is required to be the same inside and outside of the void. The metric describing the geometry within the void can be Schwarzschild or Kottler depending on whether there is a non-zero cosmological constant. Embedding a lens effectively reduces the gravitational potential's range, i.e., partially shields the lensing potential produced by the lens mass condensation. For example, a light ray grazing the boundary of a Kottler/Schwarzschild void will not be bent by the lens mass condensation (i.e., does not feel the gravitational potential of the embedded lens) and travels along a straight line path in a flat background universe. == Properties == In order to be an analytical solution of the
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Einstein's field equation, the embedded lens has to satisfy the following conditions: The mass of the embedded lens (point mass or distributed), should be the same as that from the removed sphere. The mass distribution within the void should be spherically symmetric. The cosmological constant should be the same inside and outside of the embedded lens. == History == A universe with inhomogeneities (galaxies, clusters of galaxies, large voids, etc.) represented by spherical voids containing mass condensations described as above is called a Swiss Cheese Universe. The concept of Swiss Cheese Universe was first invented by Einstein and Straus in 1945. Swiss Cheese model has been used extensively to model inhomogeneities in the Universe. For an example, effects of large scale inhomogeneities (such as superclusters) on the observed anisotropy of the temperatures of cosmic microwave background radiation (CMB) was investigated by Rees and Sciama in 1968 using Swiss cheese model (the so-called Rees-Sciama effect). Distance redshift relation in Swiss cheese universe has been investigated by Ronald Kantowski in 1969, and Dyer & Roeder in the 1970s. The gravitational lensing theory for a single embedded point mass lens in flat pressure-less Friedman-Lemaître-Robertson-Walker (FLRW) background universe with non-zero cosmological constant has been built by Ronald Kantowski, Bin Chen, and Xinyu Dai in a series papers. == Embedded Lens vs. Classical Gravitational Lens == The key difference between an embedded lens and a traditional lens is that the mass of a standard lens contributes to the mean of the cosmological density, whereas that of an embedded lens does not. Consequently, the gravitational potential of an embedded lens has a finite range, i.e., there is no lensing effect outside of the void. This is different from a standard lens where the gravitational potential of the lens has an infinite range. As a consequence of
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embedding, the bending angle, lens equation, image amplification, image shear, and time delay between multiple images of an embedded lens are all different from those of a standard linearized lens. For example, the potential part of the time delay between image pairs, and the weak lensing shear of embedded lens can differ from the standard gravitational lensing theory by more than a few percents. For an embedded point mass lens, the lens equation to the lowest order can be written θ S = θ I − θ E 2 θ I [ 1 − ( θ I / θ M ) 2 ] 3 {\displaystyle \theta _{S}=\theta _{I}-{\frac {\theta _{E}^{2}}{\theta _{I}}}\left[{\sqrt {1-(\theta _{I}/\theta _{M})^{2}}}\right]^{3}} where θ E {\displaystyle \theta _{E}} is the Einstein ring of the standard point mass lens, and θ M {\displaystyle \theta _{M}} is the angular size of the embedded lens. This can be compared with the standard Schwarzschild lens equation θ S = θ I − θ E 2 θ I {\displaystyle \theta _{S}=\theta _{I}-{\frac {\theta _{E}^{2}}{\theta _{I}}}} == References ==
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"page_id": 38866057,
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}
|
Ljubov A. Rebane (née Chagalova) (September 6, 1929 Leningrad – June 13, 1991 Tallinn) was an Estonian physicist. She graduated from Leningrad University in 1952 and received a PhD in Physics and Mathematics in 1961 from the same university. She received the USSR State Prize (Russian: Госуда́рственная пре́мия СССР) in 1986, together with Rein Avarmaa, Anšel Gorohhovski, Roman Personov, Boris Harlamov, Jevgeni Alšits, Ljudmila Bõkovskaja, Vladimir Maslov, Jaak Kikas and Konstantin Solovjov, for the cycle of articles "High-spectral-resolution spectroscopy and for the persistent spectral hole burning of molecules and solids" (Russian: Авармаа, Рейн Арнольдович, зав. сектором, Гороховский, Аншель Александрович, Кикас, Яак Вернерович, ст. н. с., Альшиц, Евгений Иосифович, Быковская, Людмила Анатольевна, мл. н. с. Института физики АН ЭССР; Маслов, Владимир Григорьевич, ст. н. с. ГОИ имени С. И. Вавилова; Ребане, Любовь Александровна, ст. н. с. ИХБФАН ЭССР; Соловьёв, Константин Николаевич, зав. лабораторией Института физики АН БССР, — за цикл работ «Фотовыжигание стабильных спектральных провалов и гелективная спектроскопия сложных молекул» (1972—1984)). == Family == She married the physicist Karl Rebane. Their children Aleksander and Inna Rebane both became physicists themselves. == References ==
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{
"page_id": 38079625,
"source": null,
"title": "Ljubov Rebane"
}
|
Osteopromotive describes a material that promotes the de novo formation of bone. Osteoconductivity describes the property of graft material in which it serves as a scaffold for new bone growth but does not induce bone growth de novo. This means that osteoconductive materials will only contribute to new bone growth in an area where there is already vital bone. Osteoinductivity describes the property of graft material in which it induces de novo bone growth with biomimetic substances, such as bone morphogenetic proteins. Such materials will contribute to new bone growth in an area where there is no vital bone, such as when implanted into muscle tissue. In contrast, osteopromotive substances will not contribute to de novo bone growth but serve to enhance the osteoinductivity of osteoinductive materials. An example of this is enamel matrix derivative, which serves to enhance the osteoinductive nature of demineralized freeze dried bone allograft (DFDBA). == See also == Bone growth factor == References ==
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{
"page_id": 27135117,
"source": null,
"title": "Osteopromotive"
}
|
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