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Homologous Pair
Homology, homologous, homologation or homological may refer to: Sciences Biology *Homology (biology), any characteristic of biological organisms that is derived from a common ancestor *Sequence homology, biological homology between DNA, RNA, or protein sequences *Homologous chromosomes, chromosomes in a biological cell that pair up (synapse) during meiosis *Homologous recombination, genetic recombination in which nucleotide sequences are exchanged between molecules of DNA * Homologous desensitization, a receptor decreases its response to a signalling molecule when that agonist is in high concentration *Homology modeling, a method of protein structure prediction Chemistry *Homologous series, a series of organic compounds having different quantities of a repeated unit * Homologous temperature, the temperature of a material as a fraction of its absolute melting point *Homologation reaction, a chemical reaction which produces the next logical member of a homologous series O ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homology (biology)
In biology, homology is similarity in anatomical structures or genes between organisms of different taxa due to shared ancestry, ''regardless'' of current functional differences. Evolutionary biology explains homologous structures as retained heredity from a common descent, common ancestor after having been subjected to adaptation (biology), adaptive modifications for different purposes as the result of natural selection. The term was first applied to biology in a non-evolutionary context by the anatomist Richard Owen in 1843. Homology was later explained by Charles Darwin's theory of evolution in 1859, but had been observed before this from Aristotle's biology onwards, and it was explicitly analysed by Pierre Belon in 1555. A common example of homologous structures is the forelimbs of vertebrates, where the bat wing development, wings of bats and origin of avian flight, birds, the arms of primates, the front flipper (anatomy), flippers of whales, and the forelegs of quadrupedalis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homology (psychology)
Homology in psychology, as in biology, refers to a relationship between characteristics that reflects the characteristics' origins in either evolution or development. Homologous behaviors can theoretically be of at least two different varieties. As with homologous anatomical characteristics, behaviors present in different species can be considered homologous if they are likely present in those species because the behaviors were present in a common ancestor of the two species. Alternatively, in much the same way as reproductive structures (e.g., the penis and the clitoris) are considered homologous because they share a common origin in embryonic tissues, behaviors—or the neural substrates associated with those behaviors—can also be considered homologous if they share common origins in development. Behavioral homologies have been considered since at least 1958, when Konrad Lorenz studied the evolution of behavior. More recently, the question of behavioral homologies has been a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homological Word
An autological word (or homological word) expresses a property that it also possesses. For example, the word "word" is a word, the word "English" is (in) English, the word "writable" is writable, and the word " pentasyllabic" has five syllables. The opposite, a heterological word, does not apply to itself. For example, the word "palindrome" is not a palindrome, "unwritable" is writable, and "monosyllabic" has more than one syllable. Unlike more general concepts of autology and self-reference, this particular distinction and opposition of autological and heterological words is uncommon in linguistics for describing linguistic phenomena or classes of words, but is current in logic and philosophy where it was introduced by Kurt Grelling and Leonard Nelson for describing a semantic paradox, later known as Grelling's paradox or the Grelling–Nelson paradox.Grelling and Nelson used the following definition when first publishing their paradox in 1908: "Let ''φ(M)'' be the word that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homologation (motorsport)
In motorsport, homologation is a testing and certification process for vehicles, circuits, and related equipment for conformance to technical standards, usually known as type approval in English-language jurisdictions. It confirms conformity to standards or categorisation criteria typically set by the sporting authority. At international and supra-national level, the Fédération Internationale de l'Automobile, FIA and Fédération Internationale de Motocyclisme, FIM mandate what must be homologated, the FIA in its International Sporting Code and appendices. National sporting authorities such as Motorsport UK must adhere to these rules but may enforce additional or specific homologation rules applicable to their series or jurisdiction, however, unaffiliated series may set their own requirements. The word homologation is derived from Greek language, Greek , . Requirements "Production-based" racing series require that racing vehicles are based on production vehicles for sale to th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homologation
Homologation (Greek language, Greek ''homologeo'', ὁμολογέω, "to agree") is the granting of approval by an official authority. This may be a court of law, a government department, or an academic or professional body, any of which would normally work from a set of rules or standards to determine whether such approval should be given. The word may be considered very roughly synonymous with ''wiktionary:Accreditation, accreditation'', and in fact in French language, French and Spanish language, Spanish may be used with regard to academic degrees (see apostille). ''Certification'' is another possible synonym, while ''to homologate'' is the infinitive verb form. In today's marketplace, for instance, products must often be homologated by some public agency to assure that they meet standards for such things as safety and environmental impact. A court action may also sometimes be homologated by a judicial authority before it can proceed, and the term has a precise legal meaning i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homological Algebra
Homological algebra is the branch of mathematics that studies homology (mathematics), homology in a general algebraic setting. It is a relatively young discipline, whose origins can be traced to investigations in combinatorial topology (a precursor to algebraic topology) and abstract algebra (theory of module (mathematics), modules and Syzygy (mathematics), syzygies) at the end of the 19th century, chiefly by Henri Poincaré and David Hilbert. Homological algebra is the study of homological functors and the intricate algebraic structures that they entail; its development was closely intertwined with the emergence of category theory. A central concept is that of chain complexes, which can be studied through their homology and cohomology. Homological algebra affords the means to extract information contained in these complexes and present it in the form of homological invariant (mathematics), invariants of ring (mathematics), rings, modules, topological spaces, and other "tangible ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homology (mathematics)
In mathematics, the term homology, originally introduced in algebraic topology, has three primary, closely-related usages. The most direct usage of the term is to take the ''homology of a chain complex'', resulting in a sequence of Abelian group, abelian groups called ''homology groups.'' This operation, in turn, allows one to associate various named ''homologies'' or ''homology theories'' to various other types of mathematical objects. Lastly, since there are many homology theories for Topological space, topological spaces that produce the same answer, one also often speaks of the ''homology of a topological space''. (This latter notion of homology admits more intuitive descriptions for 1- or 2-dimensional topological spaces, and is sometimes referenced in popular mathematics.) There is also a related notion of the cohomology of a Cochain complexes, cochain complex, giving rise to various cohomology theories, in addition to the notion of the cohomology of a topological space. Ho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homology (sociology)
Homologies are "structural 'resonances'...between the different elements making up a socio-cultural whole." (Middleton 1990, p. 9) Examples include Alan Lomax's cantometrics, which: :Distinguishes ten musical styles, dealing most fully with Eurasian and Old European styles. These are correlated with sexual permissiveness, status of women, and treatment of children as the principal formative social influences. The musical styles are at the same time symbolic or expressive of such social influences, especially in the various musical communities of Spain and Italy, and are stable, persistent. Lomax states his expectation that further study and refinement of methods of measurement will increase our understanding of the relationships of musical style and culture in a way that Western European musical notation cannot adequately accomplish. Richard Middleton (1990, p. 9-10) argues that "such theories always end up in some kind of reductionism – 'upwards', into an idealist cultu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homologous Behaviors
Homology in psychology, as in biology, refers to a relationship between characteristics that reflects the characteristics' origins in either evolution or development. Homologous behaviors can theoretically be of at least two different varieties. As with homologous anatomical characteristics, behaviors present in different species can be considered homologous if they are likely present in those species because the behaviors were present in a common ancestor of the two species. Alternatively, in much the same way as reproductive structures (e.g., the penis and the clitoris) are considered homologous because they share a common origin in embryonic tissues, behaviors—or the neural substrates associated with those behaviors—can also be considered homologous if they share common origins in development. Behavioral homologies have been considered since at least 1958, when Konrad Lorenz studied the evolution of behavior. More recently, the question of behavioral homologies has been ad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homology (anthropology)
This page is a glossary of archaeology, the study of the human past from material remains. A B C D E F G H I J K L M N O P Q R S T U V W X Y Z See also * Outline of archaeology * Table of years in archaeology * Glossary of history References Bibliography * * * * * * * * * External links About.com Archaeology Glossary {{Glossaries of science and engineering Archaeology Archaeology or archeology is the study of human activity through the recovery and analysis of material culture. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sequence Homology
Sequence homology is the homology (biology), biological homology between DNA sequence, DNA, RNA sequence, RNA, or Protein primary structure, protein sequences, defined in terms of shared ancestry in the evolutionary history of life. Two segments of DNA can have shared ancestry because of three phenomena: either a speciation event (orthologs), or a Gene duplication, duplication event (paralogs), or else a Horizontal gene transfer, horizontal (or lateral) gene transfer event (xenologs). Homology among DNA, RNA, or proteins is typically inferred from their nucleotide or amino acid sequence similarity. Significant similarity is strong evidence that two sequences are related by evolutionary changes from a common ancestral sequence. Sequence alignment, Alignments of multiple sequences are used to indicate which regions of each sequence are homologous. Identity, similarity, and conservation The term "percent homology" is often used to mean "sequence similarity”, that is the percen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homologation Reaction
In organic chemistry, a homologation reaction, also known as homologization, is any chemical reaction that converts the reactant into the next member of the homologous series. A homologous series is a group of compounds that differ by a constant unit, generally a methylene () group. The reactants undergo a homologation when the number of a repeated structural unit in the molecules is increased. The most common homologation reactions increase the number of methylene () units in saturated chain within the molecule. For example, the reaction of aldehydes or ketones with diazomethane or methoxymethylenetriphenylphosphine to give the next homologue in the series. Examples of homologation reactions include: * Kiliani-Fischer synthesis, where an aldose molecule is elongated through a three-step process consisting of: *# Nucleophillic addition of cyanide to the carbonyl to form a cyanohydrin *# Hydrolysis to form a lactone *# Reduction to form the homologous aldose * Wittig reac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
