A unit of selection is a biological entity within the hierarchy of biological organisation e.g. RNA world ... acting at these different levels. This debate has been as much about what it means to be a unit of selection ... is the unit of selection. Dawkins further expounded this view in an entire chapter called God s utility ... gene, be polygenic, or be fully environmentally determined, but the unit of selection in this case ... that is subject to natural selection . For several decades there has been intense debate among ... selection that has driven the evolution of altruism ? When it is noted that altruism reduces ... become more complex and rely on the use of game theory, for instance see Kin selection and group selection . Fundamental theory Two useful introductions to the fundamental theory underlying the unit of selection issue and debate, which also present examples of multi level selection from the entire ... or cell lineages in organisms , are Richard Lewontin Richard Lewontin s classic piece The Units of Selection ref Lewontin RC. 1970. The Units of Selection. Annual Review of Ecology, Evolution, and Systematics ... is at stake vis a vis units of selection, Lewontin writes blockquote The generality of the principles of natural selection means that any entities in nature that have variation, reproduction, and heritability ... introduction to the debate. Examples of selection at each level Below, cases of selection at the genic, cellular, individual and group level from within the multi level selection perspective are presented and discussed. Selection at the level of the gene Main gene centered view of evolution George C. Williams in his influential book Adaptation and Natural Selection was one of the first to present a gene centered view of evolution with the gene as the unit of selection, arguing that a unit of selection should exhibit a high degree of permanence. Richard Dawkins has written several books ... as units of selection. This is because replicators, owing to their permanence, should be regarded ... more details
traits or allele s of genes segregating within a population may be subject to selection . Under selection ... than others do. When these traits have a genetic basis, selection can increase the prevalence of those traits, because offspring will genetics inherit those traits from their parents. When selection ... then be said to have evolved . Scientists who do experimental genetics employ artificial selection experiments that permit the survival of organisms with user defined phenotypes. Artificial selection ... or not selection takes place depends on the conditions in which the individuals of a species find ... selection. Factors fostering selection include limits on resources nourishment, habitat space, mates ... as selective pressures . Natural selection is the most familiar type of selection by name. The breeding of dogs, cows and horses, however, represents artificial selection . Subcategories of natural selection are also sometimes distinguished. These include sexual selection , ecological selection , stabilizing selection , disruptive selection and directional selection more on these below . Selection ... neutral , selection does not occur. Meanwhile, selection does not guarantee that advantageous ... may become less common or disappear. In the face of selection even a so called deleterious allele may become universal to the members of a species. This is a risk primarily in the case of weak selection ... s. Though deleterious alleles may sometimes become established, selection may act negatively as well as positively. Negative selection decreases the prevalence of traits that diminish individuals capacity to succeed reproductively i.e. their fitness biology fitness , while positive selection ... selection are sometimes said to be selected against, while those under positive selection are said to be selected ... against shallow root architectures. Types and subtypes File Selection classification diagram.png frame right Selection is hierarchically classified into natural selection natural and artificial ... more details
Other uses Negative selection disambiguation In natural selection , negative selection ref Loewe, L. 2008 . http www.nature.com scitable topicpage Negative Selection 1136 Negative selection . Nature Education 1 1 . ref or purifying selection is the selective removal of alleles that are Mutation Harmful mutations deleterious . This can result in stabilizing selection through the purging of deleterious variations that arise. Purging of deleterious alleles can be achieved on the population genetics level, with as little as a single point mutation being the unit of selection. In such a case, carriers of the harmful point mutation have fewer offspring each generation, reducing the frequency of the mutation in the gene pool. In the case of strong negative selection on a locus, the purging of deleterious variants will result in the occasional removal of genetic linkage linked variation, producing a decrease in the level of variation surrounding the locus under selection. The accidental purging of non deleterious alleles due to such spatial proximity to deleterious alleles is called background selection . ref Brian Charlesworth Charlesworth, B. , Morgan, M. T. and Deborah Charlesworth Charlesworth, D. 1993. The effect of deleterious mutations on neutral molecular variation. Genetics 134 , 1289 1303. http www.genetics.org cgi content abstract 134 4 1289 Link ref This effect increases with higher mutation rate but decreases with higher recombination rate. ref cite journal author Hudson RR, Kaplan NL title Deleterious background selection with recombination journal Genetics volume 141 issue 4 pages 1605 17 year 1995 month December pmid 8601498 pmc 1206891 ref See Also Balancing selection Directional selection Disruptive selection Stabilizing selection Assortative mating References Reflist MolecularEvolution genetics stub Category Selection Category Genetics it Selezione ambientale ... more details
Infobox television show name The Unit image File The Unit 2006 Intertitle.png 250px caption The Unit ... 4 num episodes 69 list episodes List of The Unit episodes website The Unit was an American action drama television series that focused on a top secret military unit modeled after the real life U.S. Army special operations unit commonly known as Delta Force . The series originally aired on CBS from ... idUSTRE54J0Z620090520 agency Reuters title The Unit, Earl, Medium get the ax date May 20 ... hr content display television news e3ic8543054a8a9084d4e05790a72e1e68e title The Unit ... terrorist Unit ISBN 0 440 23733 5 , The Unit was created for television and executive produced by David ... the daily lives of Delta Force called The Unit in the show operators during training and operational missions as well as their families back home. Internationally, The Unit premiered on October ... Duncan composer Robert Duncan . Although the show focuses on an Army special ops unit, Fired Up is an adaptation ... s unit Insignia, as seen in the episode The Kill Zone 200px The Unit is the United States Army ... Special Forces Groups . The few who pass selection then undergo several more years of sophisticated ... referred to as The Unit and their US Department of Defense DOD designation is Combat Applications Group . The official cover name of The Unit in the show is the similar sounding 303rd Logistical Studies Group . In the third season s premiere, an onscreen read out specifically identifies The Unit as 1st Special Actions Group , reminiscent of 1st Special Forces Operational Detachment Delta . The Unit ... town located southeast of Kansas City. Unit members also wear the shoulder sleeve insignia of the deactivated ... part of the 1st ABCT of the 82nd Airborne Division. In later episodes, Unit members are shown as wearing the United States Special Operations Command USSOCOM patch on their Class A uniforms. The Unit ... . The wives of The Unit s Alpha Team personnel are given minimal mission or operational information ... more details
Wiktionary Unit may refer to Mathematics Unit ring theory , an element that is invertible with respect to ring multiplication 1 number , the unit number Unit vector , a of the class of objects being studied Science and technology Units software , a software program for unit conversion Units of measurement , a standardized quantity of measurement of a physical quantity Enzyme unitUnit operation , a basic step in a chemical plant process Functional unit , a component of a computer system such as the CPU Unit of blood, a measurement in blood transfusion equal to one pint or 450 ml Unit of alcohol , 10 millilitres of pure ethanol in the United Kingdom Rack unit , a measure to describe the height of rack mounted computer equipment Geological unit or rock unit, a volume of identifiable rock or ice In statistics Unit of observation , a type of entity e.g. person, house, neighborhood specifying the level at which data is collected Unit of analysis , a type of entity e.g. person, house, neighborhood specifying the level at which data is analyzed Statistical unit , a single data point, or collection ... and the arts UNIT , a fictional military organization in the science fiction television series Doctor Who Unit album Unit album , by the Australian band Regurgitator Unit art collective , a British artists collective G Unit , a hip hop music group The Units , a synthpunk band The Unit , an American television series Second unit , a team that shoots footage which is of lesser importance for the final motion picture Unit of action , a discrete piece of action or beat in a theatrical presentation UNIT Post Production , a British company The Tony Rice Unit , an American bluegrass group Other uses Unit housing , a self contained suite of rooms within a set of similar dwellings Unit of account , a monetary unit of measurement An apartment Multiple unit , a passenger train where each carriage has it own motors Military unit Strategic business unit In real time strategy games, an individual ... more details
Orphan date November 2006 att August 2010 Infobox Software name Unit logo screenshot caption collapsible author developer released latest release version latest release date latest preview version latest preview date frequently updated programming language C operating system platform size language status genre library computing library or Software framework framework license website lowercase title unitunit is a Unit Test unit testing framework module for C . The author started it as an alternative to CppUnit , which he felt was insufficiently integrated into the C language. External links http unitpp.sourceforge.net Project s site . Category C libraries Category Extreme programming Category Unit testing frameworks compu prog stub ... more details
Image FP9Au RLGN 1400.jpg thumb 300px An EMD FP9 A owned by Mackenzie Northern Railway . An A unit , in railroad terminology, is a locomotive generally a diesel locomotive diesel or electric locomotive equipped with a driving cab locomotive cab , or crew compartment, and the Multiple unit train control control system to control other locomotives in a multiple unit , and therefore able to be the lead unit in a consist of several locomotives controlled from a single position. This terminology is generally used in North America , since only there was it commonplace to build B unit s&mdash cabless locomotive units which normally could not lead a train. Typical features Typical driving cab features, and therefore A unit features, include windshields, rectangular side windows, crew seats, heating, and sometimes, radios, air conditioning and toilets. B units always lack all of these features, except that some EMD F unit s have an extra porthole style side window s for a hostler an employee permitted to move a locomotive in a yard only &mdash not on the road . Terminology This terminology has fallen out of use for newer locomotives, since it only really applied to the cab unit style of locomotive. Thus, the term cab unit is used only when an A unit has a Cab unit carbody design. Hood unit road switcher types were generally equipped with driving cabs and the term A unit was not generally applied to them, although the rare cabless road switchers were still called B units. Conversions In some cases, A units were converted to B units. If the unit had been involved in a collision which damaged the cab, it was sometimes more cost effective to rebuild the unit without the cab. In rarer cases, B units were converted to A units. The Chicago and North Western Railway converted several EMD ... to as Crandall Cabs. The BNSF also experimented with a single GP60B to make it a A unit by using a Ex ... of the unit to the middle of the unit to make room for the cab. References Pinkepank, Jerry A. 1973 ... more details
Other uses Unit disambiguation Use British English date May 2011 Use dmy dates date December 2011 universe Whoniverse organisation name UNIT organisation logo organisation type Category Fictional intelligence agencies Intelligence agency , military organisation foundation UNIT dating controversy 1968 location Worldwide Geneva , Switzerland Mount Snowdon , Wales Unit Base 5 An office building in London ... , England Manhattan , NYC , USA Airborne aircraft carrier Valiant Unit Moonbase key people Brigadier ... Shaw br Jo Grant br Sarah Jane Smith br Harry Sullivan Lieutenant Harry Sullivan br List of UNIT ... Jones br List of UNIT personnel in Doctor Who Colonel A. Mace Colonel A. Mace br List of UNIT personnel in Doctor Who General Sanchez General Sanchez br List of UNIT personnel in Doctor Who Captain Erisa Magambo Captain Erisa Magambo br List of UNIT personnel in Doctor Who Colonel Oduya Colonel ... subsid homepage http www.unit.org.uk footnotes UNIT UN ified I ntelligence T askforce, or U ... extraterrestrial threats to the Earth . In the original Doctor Who series, several UNIT personnel ... be used. However, the UNIT and UN abbreviations could be used, as long as it was not explained what ... title Calling UNIT first Russell T last Davies page p. 47 journal SFX magazine SFX month April year ... in a line of dialogue that the United Nations still supports UNIT with funding. Fictional history Main History of UNIT File UNIT wing.png 200px left thumb UNIT insignia first used in Battlefield , also seen on the http www.unit.org.uk UNIT website . File UNIT wing 2.png 200px left thumb UNIT variation insignia first used in Battlefield , also seen on the http www.unit.org.uk UNIT website . The roots of UNIT in the Doctor Who universe lie in extraterrestrial incursions featured in the Second ... Winter 1991 Special UNIT Exposed publisher Marvel UK Marvel Comics Ltd. pages 4 5 ref Following these incidents, the newly formed UNIT s baptism by fire baptism of fire was an invasion by the Cyberman ... more details
DISPLAYTITLE S unit In mathematics , in the field of algebraic number theory , an S nowiki nowiki unit generalises the idea of Unit ring theory unit of the ring of integers of the field. Many of the results which hold for units are also valid for S units. Definition Let K be a number field with ring of integers R . Let S be a finite set of prime ideals of R . An element x of K is an S unit if the principal fractional ideal x is a product of primes in S to positive or negative powers . For the ring of rational integers Z one may take S to be a finite set of prime numbers and define an S unit to be a rational number whose numerator and denominator are divisible only by the primes in S . Properties The S units form a multiplicative group containing the units of R . Dirichlet s unit theorem holds for S units the group of S units is finitely generated, with Rank of an abelian group rank maximal number of multiplicatively independent elements equal to r s , where r is the rank of the unit group and s S . S unit equation The S nowiki nowiki unit equation is a Diophantine equation u v 1 with u , v restricted to being S units of K . The number of solutions of this equation is finite and the solutions are effectively determined using estimates for linear forms in logarithms as developed in transcendence theory . A variety of Diophantine equations are reducible in principle to some form of the S unit equation a notable example is Siegel s theorem on integral points on elliptic curve s, and more generally so called hyperelliptic curves of the form y sup n sup f x . References cite book author Graham Everest coauthors Alf van der Poorten , Igor Shparlinski , Thomas Ward title Recurrence sequences series Mathematical Surveys and Monographs volume 104 publisher American Mathematical Society year 2003 isbn 0 8218 3387 1 pages 19 22 cite book author Serge Lang authorlink Serge Lang title Elliptic curves Diophantine analysis series Grundlehren der mathematischen Wissenschaften volume ... more details
In linguistics , the term T unit was coined by Kellogg Hunt in 1965. ref Hunt, K. 1965 . http eric.ed.gov ERICWebPortal custom portlets recordDetails detailmini.jsp? nfpb true& &ERICExtSearch SearchValue 0 ED113735&ERICExtSearch SearchType 0 no&accno ED113735 Grammatical structures written at three grade levels . NCTE Research report No. 3. Champaign, IL, USA NCTE. ref It is defined as the shortest grammatically allowable sentences into which writing can be split or minimally terminable unit. Often, but not always, a T unit is a sentence linguistics sentence . More technically, a T unit is a dominant clause and its dependent clauses as Hunt said, it is one main clause with all subordinate clauses attached to it Hunt 1965 20 . T units are often used in the analysis of written and spoken discourse , such as in studies on errors in second language writing. The number of error free T units may be counted, as in Robb et al. 1986 , ref Robb, T., Ross, S., & Shortreed, I. 1986 . http links.jstor.org sici?sici 0039 8322 198603 20 3A1 3C83 3ASOFOEA 3E2.0.CO 3B2 9 Salience of feedback on error and its effect on EFL writing quality . TESOL Quarterly, 20, 83 93. ref or changes in accuracy per T unit over drafts of compositions may be measured Sachs and Polio, 2007 . ref Sachs, R. and Polio, C. 2007 . http journals.cambridge.org action displayAbstract?fromPage online&aid 676824 Learners uses of two types of written feedback on a L2 writing revision task. Studies in Second Language Acquisition, 29 67 100. ref Young 1995 ref Young, R. 1995 . http www.blackwell synergy.com doi abs 10.1111 j.1467 ... 45 1 3 42. ref gives some examples of what a T unit is and is not blockquote The following elements were counted as one T unit a single clause, a matrix plus subordinate clause, two or more phrases ... t unit. Young 1995 38 blockquote References references See also Clause Sentence linguistics External ... language a unit for all reasons Applied Linguistics 21 3 354 375. Category Syntactic entities ... more details
Positive selection may refer to Positive selection as an Thymocyte Events during maturation event during thymocyte maturation Directional selection , a particular mode or mechanism of natural selection. disambig immunology T cells that express TCR can bind weakly to self antigenson MHC are selected in positive selection ... more details
Unnatural Selection may refer to tocright Literature Saurians Unnatural Selection comics Saurians Unnatural Selection comics , a 2002 American comic book published by CrossGen Unnatural Selection Buffy novel Unnatural Selection Buffy novel , a 1999 original novel based on the television series Buffy the Vampire Slayer Unnatural Selection 2006 , Gideon Oliver novel by Aaron Elkins Unnatural Selection comics , a collection of comic strips from the Far Side, drawn by Gary Larson. Television Unnatural Selection The Outer Limits Unnatural Selection The Outer Limits , a 1996 episode of The Outer Limits television show Unnatural Selection Stargate SG 1 Unnatural Selection Stargate SG 1 , a 2002 episode of the science fiction television series Stargate SG 1 Unnatural Selection Star Trek The Next Generation Unnatural Selection Star Trek The Next Generation , a 1989 episode in the second season of Star Trek The Next Generation Other Unnatural Selection album Unnatural Selection album , a 1999 album by Flotsam And Jetsam Unnatural Selection video game , a 1993 video game by Maxis Unnatural Selection , a song on Muse s 2009 album The Resistance album The Resistance Unnatural Selection , an entry in the direct to video series P.R.O.B.E. , a spin off of the BBC science fiction series Doctor Who featuring companion character Liz Shaw . See also Artificial selection Natural selection disambiguation ... more details
also Unit of selection In recent years, the limitations of earlier models have been addressed, and newer ...In evolutionary biology , group selection refers to the idea that allele s can become fixed or spread ... biology fitness of individuals within that group. Group selection was used as a popular ... Wynne Edwards, V. C. 1986 Evolution Through Group Selection , Blackwell. ISBN 0 632 01541 1 ref For several ..., G.C. 1972 Adaptation and Natural Selection A Critique of Some Current Evolutionary Thought . Princeton ... last1 Maynard Smith first1 J. authorlink John Maynard Smith year 1964 title Group selection and kin selection url journal Nature journal Nature volume 201 issue 4924 pages 1145 1147 ref and C.M. Perrins 1964 , cast serious doubt on group selection as a major mechanism of evolution , and though some scientists have pursued the idea over the last few decades, only recently have group selection ... models of the 1960s seemed to imply that the effect of group selection was negligible. Allele s are likely to be held on a population wide level, leaving nothing for group selection to select for. Additionally ... selection pressure s, individual selection will occur much faster, swamping any changes potentially favored by group selection. The Price equation can partition variance caused by natural selection at the individual level and the group level, and individual level selection generally causes greater effects. Experimental results starting in the late 1970s demonstrated that group selection was far ... 2407552 last1 Wade first1 M. J. year 1977 title An experimental study of group selection journal Evolution ... that the early group selection models were flawed because they assumed that genes acted independently ... based interactions among individuals, were an important source of the response to group selection e.g. ref Goodnight, C. J. and L. Stevens. 1997. Experimental studies of group selection What do they tell us about group selection in nature. American Naturalist 150 S59 S79. ref . As a result ... more details
less fit variants. The unit of selection can be the individual or it can be another level within the hierarchy ...Use American English date July 2011 Other uses Natural Selection disambiguation Evolutionary biology Natural selection is the gradual, non random , process by which trait biology biological traits become ... success are also important, an issue that Charles Darwin developed in his ideas on sexual selection , for example. Natural selection acts on the phenotype , or the observable characteristics of an organism ... emergence of new species . In other words, natural selection is an important process though ... selection , in which humans favour specific traits, in natural selection the environment acts as a sieve through which only certain variations can pass. Natural selection is one of the cornerstones ... of Species , ref name origin Darwin C 1859 On the Origin of Species by Means of Natural Selection ... 2 On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life . ref in which natural selection was described as analogous to artificial selection ... are systematically favored for reproduction. The concept of natural selection was originally developed ... . Natural selection remains the primary explanation for adaptive evolution . General principles File ... of natural selection on peppered moth evolution . ref name Peppered Moth cite web url http ... of natural selection predates the understanding of genetics, the mechanism of heredity for all known life forms. In modern terms, selection acts on an organism s phenotype, or observable characteristics ... distinction . This is the link between natural selection and genetics, as described in the modern ... evolutionary mechanisms such as genetic drift and gene flow , natural selection appears to be the most ... natural selection has slightly different definitions in different contexts. It is most often defined .... However, natural selection is blind in the sense that changes in phenotype physical and behavioral ... more details
Wiktionary selectionSelection is the consistent differential survival and reproduction among genotypes. Selection may also refer to In computer science Selection user interface Selection genetic algorithm Selection relational algebra Selection based search , a search engine system in which the user invokes a search query using only the mouse Selection algorithm , an algorithm that finds the k th smallest number in a list Other uses Selected album Selected album , the compilation album by Recoil Selection Australian history , an area of crown land acquired under legislation Selection album Selection album , by 54 40 Selective school Selection in schools , the admission of students on the basis of selective critera Selection effect , a distortion of data arising from the way that the data are collected Selektion , selection of prisoners for execution at a Nazi concentration camp disambig de Selektion es Selecci n fr S lection gl Selecci n ja no Seleksjon sk Selekcia ... more details
How to date September 2009 Material selection is a step in the process of designing any physical object. In the context of product design , the main goal of material selection is to minimize cost while meeting product performance goals. ref George E. Dieter 1997 . Overview of the Materials Selection Process , ASM Handbook Volume 20 Materials Selection and Design . ref Systematic selection of the best material for a given application begins with list of materials properties properties and costs of candidate materials. For example, a thermal blanket must have poor thermal conductivity in order to minimize heat transfer for a given temperature difference. Systematic selection for applications requiring multiple criteria is more complex. For example, a rod which should be stiff and light requires a material with high Young s modulus and low density . If the rod will be pulled in tension, the specific modulus , or modulus divided by density math E rho math , will determine the best material. But because a plate s bending stiffness scales as its thickness cubed, the best material for a stiff ... name ashby cite book last Ashby first Michael authorlink M. F. Ashby title Materials Selection in Mechanical ... E rho math . Using a log scale on both axes facilitates selection of the material with the best plate ... ref Cost issues Cost of materials plays a very significant role in their selection. The most straightforward ..., this number is closer to 450 kg, and for spacecraft, launch costs around 20,000 kg dominate selection ..., cost per kg is not the only important factor in material selection. An important concept is cost per unit of function . For example, if the key design objective was the stiffness of a plate of the material ... of technical and price properties is a hard process to achieve manually, so rational material selection ... of its selection functionality from Granta Design chaired by Prof. M. Ashby DEFAULTSORT Material Selection Categories Category Materials science Category Product development Category Design ... more details
Negative selection may refer to In biology Negative selection natural selection , in natural selection it refers to the selective removal of rare alleles that are deleterious Negative selection artificial selection , in artificial selection it refers to where negative, rather than positive, traits of a species are selected for In politics Negative selection politics , is a process that occurs in rigid hierarchies, most notably dictatorships In immunology Negative selection immunology T cells that recognize self MHC molecules and peptides with high affinity are deleted from the repertoire of cells. Central tolerance is produced. Avoids auto immunity. Occurs after positive selection. disambig it Selezione negativa ... more details
Best Selection may refer to Best Selection Japan album Best Selection Japan album , 1994 Best Selection Jimsaku album Best Selection Jimsaku album Best Selection 2010 , a greatest hits album by Korean boy band TVXQ disambiguation Short pages monitor This long comment was added to the page to prevent it from being listed on Special Shortpages. It and the accompanying monitoring template were generated via Template Long comment. Please do not remove the monitor template without removing the comment as well. ... more details
The Ultra Selection may refer to The Ultra Selection Mantronix album The Ultra Selection Mantronix album , 2005 The Ultra Selection Spandau Ballet album The Ultra Selection Spandau Ballet album , 2005 disambiguation Short pages monitor This long comment was added to the page to prevent it from being listed on Special Shortpages. It and the accompanying monitoring template were generated via Template Long comment. Please do not remove the monitor template without removing the comment as well. ... more details
In computing and user interface engineering , a column selection is a text selection feature found in text editor s which allows the user to select characters in a grid like fashion. This is usually initiated by pressing the alt key instead of the shift key to select text when drag and drop ping. The feature is known by different names in different applications block selection LibreOffice Writer ref http help.libreoffice.org Writer Selection Mode Writer Selection Mode LibreOffice Help ref column selection EditPlus ref http editplus.info wiki FAQ FAQ EditPlus Wiki ref , Vim text editor vi , Emacs non linear text selection TextEdit ref http hints.macworld.com article.php?story 20050509093516708 10.4 Use non linear text selection in TextEdit ref rectangular selection jEdit ref http www.jedit.org users guide selection.html Selecting Text jEdit ref References reflist computing stub Category User interface techniques ... more details
Truncation selection is a Selection genetic algorithm selection method used in genetic algorithm s to select potential candidate solutions for recombination. In truncation selection the candidate solutions are ordered by fitness, and some proportion, p, e.g. p 1 2, 1 3, etc. , of the fittest individuals are selected and reproduced 1 p times. Truncation selection is less sophisticated than many other selection methods, and is not often used in practice. It is used in Muhlenbein s Breeder Genetic Algorithm . ref cite journal journal Evolutionary Computation year 1993 title Predictive Models for the Breeder Genetic Algorithm author H Muhlenbein, D Schlierkamp Voosen url http citeseer.comp.nus.edu.sg rd 0,730860,1,0.25,Download http qSqqSqwww.ais.fraunhofer.deqSq 257EmuehlenqSqpublicationsqSqgmd as ga 93 01.ps ref References reflist compu AI stub comp sci stub bioinformatics stub Category Genetic algorithms ... more details
Tournament selection is a method of selecting an individual from a population of individuals in a genetic algorithm . Tournament selection involves running several tournaments among a few individuals chosen at random from the population. The winner of each tournament the one with the best fitness is selected for Crossover genetic algorithm crossover . Selection pressure is easily adjusted by changing the tournament size. If the tournament size is larger, weak individuals have a smaller chance to be selected. Tournament selection pseudo code choose k the tournament size individuals from the population at random choose the best individual from pool tournament with probability p choose the second best individual with probability p 1 p choose the third best individual with probability p 1 p 2 and so on... Deterministic tournament selection selects the best individual when p 1 in any tournament. A 1 way tournament k 1 selection is equivalent to random selection. The chosen individual can be removed from the population that the selection is made from if desired, otherwise individuals can be selected more than once for the next generation. Tournament selection has several benefits it is efficient to code, works on parallel architectures and allows the selection pressure to be easily adjusted. See Also Fitness proportionate selection Reward based selection References External links http citeseerx.ist.psu.edu viewdoc download jsessionid 621DB995CF9017353A57518149E3CAA4?doi 10.1.1.30.6625&rep rep1&type pdf Genetic Algorithms, Tournament Selection, and the Effects of Noise by Brad L. Miller and David E. Goldberg Portable Document Format PDF link . http citeseerx.ist.psu.edu viewdoc download?doi 10.1.1.19.1850&rep rep1&type pdf Tournament Selection in XCS by Martin V. Butz, Kumara Sastry and David E. Goldberg Portable Document Format PDF link . Category Genetic algorithms ... more details
Tandem selection is a method of artificial selection in which useful traits are selected for sequentially. For instance, one could select for both increased milk Crop yield yield and increased milk fat content in cow s via tandem selection by first selecting those with the best of one trait, say those that produce highest milk yield, and then when that trait is at a satisfactory level, by starting to select for those cows that produce milk with the greatest milk fat content instead. However, for cows to produce milk with greater fat content, yield may have to go down due to, perhaps, limits of the cows metabolism . So, while you are selecting for cows which have increased milk fat content, the yield of milk they are producing may also go down, thus reversing the selection process previously performed to increase it. Therefore, tandem selection has a major disadvantage to other major types of artificial selection for multiple traits, such as culling and index selection , as there is a tendency for the last trait to be lost as the next is being selected. Category Breeding Genetics stub ... more details
unreferenced date August 2010 Selection ratio refers to the ratio of the number job positions to the number of job applicants and is used in the context of selection and recruitment . It is typically assumed to be a number between 0 and 1 where a number closer to zero implies that there are many applicants for any one position. The selection ratio provides information about the value of assessment tools, such as interviews, work samples, and psychometric tests. When the selection ratio is close to one, most applicants will need to be hired in order to fill the available positions. As such knowing that one applicant is likely to perform better than another is of limited value. In contrast when the selection ratio is closer to zero, assessment tools have greater value in indicating which subset of job applicants are likely to perform best. Estimates of the selection ratio can form part of estimates of utility for a given selection and recruitment system. Employment Category Recruitment Category Employment Category Human resource management ja ... more details
Multiple issues unreferenced December 2009 original research September 2007 Ecological selection or environmental selection or survival selection or individual selection or asexual selection refers to natural selection minus sexual selection , i.e. strictly ecological processes that operate on a species ... February 2007 The variant names describe varying circumstances where sexual selection is wholly ... selection can be said to be taking place in any circumstance where inheritance of specific ... is hermaphroditic or asexually reproducing, an ecological selection is taking place. In sexual reproduction ... suppression of sexual selection factors prevents the normal sexual competition rituals and selection from taking place, but which also prevent artificial selection from operating, e.g. arranged marriages ... force. Ecological selection vs sexual selection In cases where ecological and sexual selection factors ... be important to distinguish them as sub processes within natural selection. For instance, Ceratogaulus ... no longer run or evade predators thus ecological selection seems to have ultimately trumped sexual. It is also important to distinguish ecological selection in cases of extreme ecological abundance, e.g. the human built environment , cities or zoos, where sexual selection must generally predominate ..., however it becomes a sexual selection factor. Similar phenomena can be said to exist in humans ... selection from sexual is useful especially in such extreme cases Above examples demonstrate exceptions rather than a typical selection in the wild. In general, ecological selection is assumed to be the dominant process in natural selection , except in highly cognitive species that do not, or do not always ... of its sexual fitness under normal sexual selection processes for that species. For example, if only ... to lack of males, sexual selection has been suppressed by an ecological selection the disaster . Such situations ... such catastrophic events where ecological selection predominates can lead to a population with specific ... more details
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