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Artykuły w czasopismach na temat "Clinal variation"
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Stock, Amanda J., Brandon E. Campitelli i John R. Stinchcombe. "Quantitative genetic variance and multivariate clines in the Ivyleaf morning glory, Ipomoea hederacea". Philosophical Transactions of the Royal Society B: Biological Sciences 369, nr 1649 (19.08.2014): 20130259. http://dx.doi.org/10.1098/rstb.2013.0259.
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Clinal variation is commonly interpreted as evidence of adaptive differentiation, although clines can also be produced by stochastic forces. Understanding whether clines are adaptive therefore requires comparing clinal variation to background patterns of genetic differentiation at presumably neutral markers. Although this approach has frequently been applied to single traits at a time, we have comparatively fewer examples of how multiple correlated traits vary clinally. Here, we characterize multivariate clines in the Ivyleaf morning glory, examining how suites of traits vary with latitude, with the goal of testing for divergence in trait means that would indicate past evolutionary responses. We couple this with analysis of genetic variance in clinally varying traits in 20 populations to test whether past evolutionary responses have depleted genetic variance, or whether genetic variance declines approaching the range margin. We find evidence of clinal differentiation in five quantitative traits, with little evidence of isolation by distance at neutral loci that would suggest non-adaptive or stochastic mechanisms. Within and across populations, the traits that contribute most to population differentiation and clinal trends in the multivariate phenotype are genetically variable as well, suggesting that a lack of genetic variance will not cause absolute evolutionary constraints. Our data are broadly consistent theoretical predictions of polygenic clines in response to shallow environmental gradients. Ecologically, our results are consistent with past findings of natural selection on flowering phenology, presumably due to season-length variation across the range.
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Stocker, Ann Jacob, Brad Foley i Ary Hoffmann. "Inversion frequencies in Drosophila serrata along an eastern Australian transect". Genome 47, nr 6 (1.12.2004): 1144–53. http://dx.doi.org/10.1139/g04-078.
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Clinal patterns over broad geographic regions provide a way of identifying characteristics of species under selection and are increasingly being used in quantitative trait locus mapping of adaptive genetic variation in Drosophila. However, interpretations of clinal patterns can be complicated by inversions that also vary clinally and reduce recombination in some parts of the genome. Drosophila serrata (Malloch) is an Australian endemic species being used to investigate the genetic basis of geographic variation in climatic adaptation and mate recognition. Here we describe inversions in D. serrata populations from the east coast of Australia, covering tropical and temperate regions. Seven autosomal paracentric inversions and 1 apparently complex X chromosome arrangement were identified from these populations. All inverted arrangements were relatively more common in tropical populations; 2 common inversions showed clinal patterns over part of the range of D. serrata. Inversion polymorphism was relatively higher in tropical populations and almost absent in populations near the cooler southern border, in agreement with findings on other Drosophila species. While these patterns will complicate mapping of adaptive variation in D. serrata, they suggest that this species will be useful in investigatingthe dynamics of inversion-trait associations in natural populations.Key words: inversion polymorphism, geographic variation, latitudinal clines, Drosophila serrata.
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UMINA, PAUL A., ARY A. HOFFMANN, ANDREW R. WEEKS i STEPHEN W. MCKECHNIE. "An independent non-linear latitudinal cline for the sn-glycerol-3-phosphate (α-Gpdh) polymorphism of Drosophila melanogaster from eastern Australia". Genetical Research 87, nr 1 (luty 2006): 13–21. http://dx.doi.org/10.1017/s0016672306007919.
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Latitudinal variation of the polymorphic sn-glycerol-3-phosphate (α-Gpdh) locus in Drosophila melanogaster has been characterized on several continents; however, apparent clinal patterns are potentially confounded by linkage with an inversion, close associations with other genetic markers that vary clinally, and a tandem α-Gpdh pseudogene. Here we compare clinal patterns in α-Gpdh with those of other linked markers by testing field flies from eastern Australian locations collected in two separate years. The α-Gpdh variation exhibited a consistent non-linear cline reflecting an increase in the α-GpdhF allele at extreme latitudes. This pattern was not influenced by the In(2L)t inversion wherein this locus is located, nor was it influenced by the presence of the α-Gpdh pseudogene, whose presence was ubiquitous and highly variable among populations. The α-Gpdh pattern was also independent of a cline in allozyme frequencies at the alcohol dehydrogenase (Adh) locus, and two length polymorphisms in the Adh gene. These results suggest clinal selection at the α-Gpdh locus that is partially or wholly unrelated to linear climatic gradients along the eastern coast of Australia.
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Titus, Robert. "Clinal variation, heterochrony, and facies in the Trentonian Sowerbyella Lineage (Ordovician, New York State)". Journal of Paleontology 66, nr 5 (wrzesień 1992): 758–71. http://dx.doi.org/10.1017/s0022336000020783.
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Clinal variation is systematic, morphologic variation within a species along a geographic or ecologic gradient. While common among today's biotas, it has rarely been well documented in the fossil record. It is, however, clearly displayed among the large populations of the Trentonian brachiopod genus Sowerbyella. In general, shallow agitated waters were populated by specimens with flat or round pedicle valve exteriors and ornately sculptured brachial valve interiors. Deeper, quieter facies were populated by forms with medial folds on pedicle valve exteriors and plain brachial valve interiors. This clinal variation was apparently the product of heterochrony with either the shallow-water forms having been peramorphic or the deeper water forms having been paedomorphic.The distributions of the Sowerbyella clines are directly related to the facies developed within approximately eight million years of continuously deposited strata of the Trenton Limestone. Evolution of the Trentonian species of Sowerbyella appears to have been phyletic and locally adaptive. New clinal variants evolved by orthoselection during episodes when new environments were becoming available for occupation. The lower Trentonian transgression and the middle Trentonian shallowing were the major examples. Some clinal variants were eliminated when they failed to pass through facies bottlenecks in the lower and upper Trentonian. Thus, the history of the Sowerbyella lineage of the Trenton Group is the product of the facies-controlled production and selection of clinal variants. Clinal variation appears to be a central factor of phyletic evolution.Sowerbyella kayi n. sp. is described.
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Campoy, J. A., D. Ruiz, N. Cook, L. Allderman i J. Egea. "Clinal variation of dormancy progression in apricot". South African Journal of Botany 77, nr 3 (sierpień 2011): 618–30. http://dx.doi.org/10.1016/j.sajb.2010.12.006.
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Fritsch, Peter W., i Shannon D. Lucas. "Clinal Variation in the Halesia carolina Complex (Styracaceae)". Systematic Botany 25, nr 2 (kwiecień 2000): 197. http://dx.doi.org/10.2307/2666639.
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Chikhi, Lounès, Giovanni Destro-Bisol, Vincenzo Pascali, Vanessa Baravelli, Marina Dobosz i Guido Barbujani. "Clinal Variation in the Nuclear DNA of Europeans". Human Biology 81, nr 5-6 (grudzień 2009): 625–38. http://dx.doi.org/10.3378/027.081.0611.
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Titus, Robert. "Clinal variation in the evolution of Ectenocrinus simplex". Journal of Paleontology 63, nr 1 (styczeń 1989): 81–91. http://dx.doi.org/10.1017/s0022336000040993.
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The crinoid Ectenocrinus has unusual trimeric columnals which make it instantly recognizable. In northern New York State such columnals first appear in the deep shelf facies of the lower Trenton Group (the Sugar River Limestone). In these strata the columnals display nearly triangular shapes with triangular lumina and represent a new species, E. triangulus. A small minority of the columnals of these early forms are round with five-pointed lumina.A definite cline had developed by middle Trentonian time. Deep-water columnals display the ancestral triangular form, whereas adjacent, shallow-water forms are rounder and have the five-pointed or pentagonal lumina. These round types came to be the beneficiaries of middle Trentonian facies changes. This was a time when the eastern bank margin steepened and narrowed. The deep shelf habitat shrank to the east and disappeared. Trapped in this shrinking sea floor setting, the populations of the deep-water members of the cline dwindled and disappeared before late Trentonian time. Only the round form with a pentagonal lumen survived. This form, Ectenocrinus simplex, was a great success; its numbers increased and its range expanded throughout the remainder of Trentonian time.The transition from Ectenocrinus triangulus to E. simplex is seamless. No boundary, other than an arbitrary one, can be recognized. A simple and gradual shift of phenotype abundance characterized the event.
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Verrelli, Brian C., i Walter F. Eanes. "Clinal Variation for Amino Acid Polymorphisms at thePgmLocus inDrosophila melanogaster". Genetics 157, nr 4 (1.04.2001): 1649–63. http://dx.doi.org/10.1093/genetics/157.4.1649.
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AbstractClinal variation is common for enzymes in the glycolytic pathway for Drosophila melanogaster and is generally accepted as an adaptive response to different climates. Although the enzyme phosphoglucomutase (PGM) possesses several allozyme polymorphisms, it is unique in that it had been reported to show no clinal variation. Our recent DNA sequence investigation of Pgm found extensive cryptic amino acid polymorphism segregating with the allozyme alleles. In this study, we characterize the geographic variation of Pgm amino acid polymorphisms at the nucleotide level along a latitudinal cline in the eastern United States. A survey of 15 SNPs across the Pgm gene finds significant clinal differentiation for the allozyme polymorphisms as well as for many of the cryptic amino acid polymorphisms. A test of independence shows that pervasive linkage disequilibrium across this gene region can explain many of the amino acid clines. A single Pgm haplotype defined by two amino acid polymorphisms shows the strongest correlation with latitude and the steepest change in allele frequency across the cline. We propose that clinal selection at Pgm may in part explain the extensive amino acid polymorphism at this locus and is consistent with a multilocus response to selection in the glycolytic pathway.
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MCKAY, BAILEY D. "PHENOTYPIC VARIATION IS CLINAL IN THE YELLOW-THROATED WARBLER". Condor 110, nr 3 (sierpień 2008): 569–74. http://dx.doi.org/10.1525/cond.2008.8482.
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Holman, James, i n/a. "Clines, Species and Eucalypts: An Evolutionary Perspective". Griffith University. Australian School of Environmental Studies, 2003. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20030527.124144.
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Two eucalypt clines were examined using morphological, ecophysiological and molecular analyses. The species complexes examined were an ironbark complex (Eucalyptus melanophloia x E. whitei) and a box complex (E. brownii x E. populnea). Both of these complexes demonstrate continuous morphological variation across their clines. The origin of these morphological clines has previously been interpreted as the product of secondary contact between allopatric species. In this study, an analysis of morphological variation across the clines did not identify an increase in trait variance in the intermediate populations, which suggests that previous theories concerning the origin of these clines may not be valid. Genetic structuring in nuclear and chloroplast DNA was examined across the clines to investigate whether the morphological clines were the product of secondary contact between two independent evolutionary lineages, or whether the clines represent a single evolutionary lineage that has undergone primary differentiation. The microsatellite analyses indicated that there was little genetic structuring across either cline, and that there were only low levels of population differentiation. The lack of hierarchical structuring in the distribution of nuclear genetic variation suggests that these clines are unlikely to be the product of recent gene flow between two formerly allopatric species/populations. A nested clade analysis of the JLA+ region of the cpDNA provides additional evidence to reject the null hypothesis that the morphospecies classifications represent distinct evolutionary lineages. Instead the analyses indicate that each cline represents a single cohesion species and a single evolutionary lineage. The phylogeographic distribution of cpDNA haplotypes is likely to have resulted from restricted seed mediated gene flow with isolation by distance. A more cogent explanation for the clines, based on the genetic data, is that they have arisen through the process of continuous morphological diversification that has been promoted by a directional selection gradient. Drought experiments were conducted in the glasshouse to investigate whether differences in physiological performance under water stress helps to explain the maintenance of the ironbark cline. Under increasing water stress, the morphotypes showed differences in their ability to maintain water status and photosynthetic rates, yet there was no obvious pattern to these differences across the cline. Physiological differences are therefore inadequate to explain the maintenance of the ironbark cline and highlight the compensatory role that morphological variation may play in alleviating water stress. The value of adopting the cohesion species concept and a hypothesis-testing framework to assess species status is demonstrated in this study. This framework provided a statistical approach to distinguish independent evolutionary lineages from interspecific populations and provides evidence to refute the current species status of the species complexes studied. Eucalypt classification is predominantly based on morphology, which results in taxonomic classification that may not reflect genealogical relationships. This is due to the disparity between morphological and phylogenetic relationships. I therefore suggest that current presumptions regarding the prevalence and importance of hybridisation within the genus may reflect taxonomic classification. An accurate assessment of the prevalence and importance of hybridisation requires species classification to be based on genealogical relationships.
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Holman, James. "Clines, Species and Eucalypts: An Evolutionary Perspective". Thesis, Griffith University, 2003. http://hdl.handle.net/10072/365394.
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Two eucalypt clines were examined using morphological, ecophysiological and molecular analyses. The species complexes examined were an ironbark complex (Eucalyptus melanophloia x E. whitei) and a box complex (E. brownii x E. populnea). Both of these complexes demonstrate continuous morphological variation across their clines. The origin of these morphological clines has previously been interpreted as the product of secondary contact between allopatric species. In this study, an analysis of morphological variation across the clines did not identify an increase in trait variance in the intermediate populations, which suggests that previous theories concerning the origin of these clines may not be valid. Genetic structuring in nuclear and chloroplast DNA was examined across the clines to investigate whether the morphological clines were the product of secondary contact between two independent evolutionary lineages, or whether the clines represent a single evolutionary lineage that has undergone primary differentiation. The microsatellite analyses indicated that there was little genetic structuring across either cline, and that there were only low levels of population differentiation. The lack of hierarchical structuring in the distribution of nuclear genetic variation suggests that these clines are unlikely to be the product of recent gene flow between two formerly allopatric species/populations. A nested clade analysis of the JLA+ region of the cpDNA provides additional evidence to reject the null hypothesis that the morphospecies classifications represent distinct evolutionary lineages. Instead the analyses indicate that each cline represents a single cohesion species and a single evolutionary lineage. The phylogeographic distribution of cpDNA haplotypes is likely to have resulted from restricted seed mediated gene flow with isolation by distance. A more cogent explanation for the clines, based on the genetic data, is that they have arisen through the process of continuous morphological diversification that has been promoted by a directional selection gradient. Drought experiments were conducted in the glasshouse to investigate whether differences in physiological performance under water stress helps to explain the maintenance of the ironbark cline. Under increasing water stress, the morphotypes showed differences in their ability to maintain water status and photosynthetic rates, yet there was no obvious pattern to these differences across the cline. Physiological differences are therefore inadequate to explain the maintenance of the ironbark cline and highlight the compensatory role that morphological variation may play in alleviating water stress. The value of adopting the cohesion species concept and a hypothesis-testing framework to assess species status is demonstrated in this study. This framework provided a statistical approach to distinguish independent evolutionary lineages from interspecific populations and provides evidence to refute the current species status of the species complexes studied. Eucalypt classification is predominantly based on morphology, which results in taxonomic classification that may not reflect genealogical relationships. This is due to the disparity between morphological and phylogenetic relationships. I therefore suggest that current presumptions regarding the prevalence and importance of hybridisation within the genus may reflect taxonomic classification. An accurate assessment of the prevalence and importance of hybridisation requires species classification to be based on genealogical relationships.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Australian School of Environmental Studies
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Dickens, Jeremy Kenneth. "Taxonomy of Trogon rufus (Gmelin, 1788) and Amazonian ring-shaped clinal variation". Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/38/38131/tde-15022016-164253/.
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We reviewed the taxonomy of the Trogon rufus species-complex under the premises of the Biological Species Concept. Putative taxonomic units, breaks and transition zones, were visualised by heatmaps and isophenes (phenotypic contour lines) of the colour, barring, morphometric and song characters and tested by discriminant function analyses. Colourmetric data were obtained via spectrometry and barring patterns analysed via high quality digital photographs. We found four distinct biological species. Trogon chrysochloros Pelzeln 1856 from the Atlantic Forest with its denser and blacker undertail and wing covert barring, larger size and faster, generally higher song with more notes. Its upperparts vary from bluer to more coppery-green with increasing altitude. The bill is also relatively smaller and more serrated, linked to a diet that consists almost exclusively of large arthropods, making it the most insectivorous new world Trogon species yet known, which may account for its relative rarity compared to other Trogonids with which it is sympatric. Trogon tenellus Cabanis 1862, from Central America, and Trogon cupreicauda Chapman 1914 from the Chocó-Magdalena provide a classic case of typical biological species, coming into contact in the extreme NW Chocó Province, Colombia, but without intermediate forms. T. tenellus is identified by its blue to blue-green uppertail, blue or grey eye-rings, grey tarsi and song with 2-4 notes, longer note duration and greater change in peak and high frequencies between the intro note and loudsong. This contrasts with the shiny olive-green to coppery green uppertails, yellow eye-ring, usually olive tarsi, brown wash on the undertail of females and song with 6-8 notes of shorter duration and little change in frequency between the intro note and loudsong of T. cupreicauda. T. cupreicauda varies clinally from generally bluer- to more coppery-green plumage and from thicker to thinner black bars in a gradient from the Pacific coast on the border with Ecuador to the Magdalena Valley. The greater difference in colour and barring relative to T. tenellus in the region they come into contact provides possible evidence of character displacement as a result of the competitive exclusion between these two species, maintaining their parapatric distributions. The Amazonian population belongs to a single species, Trogon rufus Gmelin 1788, but with two highly distinct forms that we designate as Trogon rufus rufus in the Guiana Shield and Trogon rufus sulphureus in S & W Amazonia, for which Todd\'s amazonicus is synonymised. They are morphologically and, to a lesser extent, vocally distinct across the lower Rio Negro and matrix of highland and open habitats of the Rio Branco basin but show limited character exchange between the 52-58th parallels west on the southern bank of the Amazon, centred around the Rio Arapiuns on the left bank of mouth of the Tapajos. We postulate that this is the result of secondary contact as a consequence of shifts in the course of the main channel of the Amazon River at times of lower sea levels during the Plio-Pleistocene. T .r. sulphureus is identified by a typically coppery uppertail with subterminal tailband of greener hue, yellow eye-ring, low barring density and broad black bars of the undertail and wing-coverts barring with and lack of a pectoral band. They are also sometimes distinguishable in song by a higher frequency introduction note and/or more pronounced descending modulation across the loudsong. This varies clinally on a west-east gradient, from strong-coppery to shiny olive-green uppertails with more to less distinct subterminal tailbands, diminishing black bar widths with corresponding increasing density and decreasing intro note low frequency. T. r. rufus have green uppertails, blue eye-rings, presence or absence of a white pectoral band and denser undertail and wing panel barring with thinner black bars. These characters were shown to change as a function of geographic distance between specimens of sulphureus and rufus, connected via the \'Arapiuns contact zone\', suggesting isolation by distance. This is reminiscent of a ring species pattern and two specimens with a possible mixture of characters were indeed found from the upper Rio Negro and in Pantepui, where T. r. rufus and T. r. sulphureus would be expected to come into contact, effectively \'closing the ring\'. Whether Trogon rufus constitutes a valid ring species requires further testing, preferably including molecular characters, but this clearly illustrates that the distinction between clinal variation and ring-species is a matter of degree, not kind, with the formation of the ring-species necessarily passing through a clinal stage with no overlap between terminal taxa. We therefore propose the concept of a loop species, where the terminal forms do not overlap but are connected via a series of intergrading populations. It seems likely that such patterns are more widespread in Amazonia than presently known due to the propensity for clinal variation and parapatric speciation lended by its massive geographical extent and abundance of biogeographical semi-permeable barriers. With regards to the population from the Pernambuco Center of Endemism, the few records suggest that it is a valid taxonomic unit. It has the unique combination of a song very similar to T. r. sulphureus due to the high introduction note frequency and pronounced descent in frequencies across the loudsong, with a corresponding widening range but moderately large size, serrated bill and blue eye-ring but this certainly requires confirmation. This requires urgent attention, as the remnant population is very small and localised, recorded only from the Murici municipality, Alagoas.Nós revisamos a taxonomia do complexo Trogon rufus sob o conceito Biológico de Espécies. Unidades taxonômicas possíveis, quebras e zonas de transição taxonômicas foram definidas usando mapas de calor e isofenas (linhas de contorno de fenótípo) baseados em caráteres de cor, barramento e morfometria. Esses possíveis táxons foram testados pelas análises de discriminantes. Dados de coloração foram obtidos por meio de espectrometria, e os padrões de barramento por meio de fotos de alta qualidade. Nós encontramos quatro espécies biológicas distintas Trogon chrysochloros Pelzeln 1856, da Mata Atlântica, diagnosticável pelo barramento mais escuro e denso na face inferior da cauda e coberteiras da asa, maior tamanho corpóreo, canto mais rápido, com mais notas e de frequência mais alta. Suas partes superiores (cabeça, dorso e cauda) variam de azul a verde acobreado com o aumento da altitude. O bico também é relativamente menor e mais serrilhado, o que está ligado a uma dieta que consiste quase exclusivamente de grandes artrópodes, fazendo desta espécie o Trogon mais insetívoro do mundo, o que deve ser a razão de sua relativa raridade quando comparado a outros Trogonidae com os quais vive em simpatia. Trogon tenellus Cabanis 1862, da América Central, e Trogon cupreicauda Chapman 1914, do Chocó-Magdalena, formam um caso clássico de espécies biológicas, entrando em contato no extremo noroeste da província de Chocó, na Colômbia, sem a presença de formas intermediárias. T. tenellus é identificável pela face superior da cauda azul ou azul esverdeado, anel perioftálmico azul ou cinza, tarso cinza, e voz com de 2 a 4 notas, maior duração das notas e maior mudança entre frequência de pico e frequência alta entre a nota introdutória e nota principal. Essas características contrastam com a cor verde-oliva brilhante da face superior da cauda, anel perioftámico amarelo, tarso geralmente oliva, presença de marrom claro na face inferior da cauda das fêmeas e canto com entre 6 e 8 notas, de menor duração, pouca mudança na frequência entre a primeira nota e o canto principal de T. cupreicauda. Este varia clinalmente de azul para uma plumagem mais verde acobreada e de barramento preto mais espesso para mais fino em uma gradiente da costa do Pacífico, do noroeste do Equador até o Vale do Magdalena. A maior distinção de estados de caráter relativa a T. tenellus na região onde os dois grupos se encontram provê uma possível evidência de deslocamento de caracteres como resultado de exclusão competitiva entre estas duas espécies, mantendo suas distribuições parapátricas. A população amazônica pertence a única espécie biológica Trogon rufus Gmelin 1788, mas com duas formas altamente distintas que designamos como Trogon rufus rufus do Escudo Guianense, e Trogon rufus sulphureus no sul e oeste da Amazônia, com a qual amazonicus de Todd é sinonimizada. Estas são morfologicamente, e em menor escala, vocalmente distintas nas duas margens do baixo Rio Negro e áreas abertas e/ou montanhosas da bacia do Rio Branco, mas apresentam troca de caracteres limitada nas longitudes entre 52 e 58 Oeste na margem sul do Rio Amazonas, centrado nos arredores do Rio Arapiuns, na margem esquerda da foz do Tapajós. Nós postulamos que isto é um resultado de contato secundário, como consequência de mudanças no curso principal do Rio Amazonas em tempos de níveis mais baixos do mar durante o Plio-Pleistoceno. T. r. sulphureus é identificado pela coloração tipicamente acobreada da face superior da cauda com uma banda sub-terminal de tonalidade esverdeada, anel perioftálmico amarelo, barras negras espessas e de baixa densidade na face inferior da cauda e nas coberteiras das asas e pela ausência de uma faixa peitoral. Em certos casos eles também podem ser distinguíveis pela voz com uma nota introdutória de maior frequência e/ou uma modulação descendente mais pronunciada no canto principal. Este grupo varia clinalmente em gradiente de oeste para leste, de uma coloração cobre forte até verde oliva na face superior da cauda com faixa sub-terminal mais ou menos distinta, anel perioftálmico azul, presença ou ausência de uma faixa peitoral branca e barramento na face inferior da cauda e coberteiras de menor espessura e, consequentemente, maior densidade. Nossos dados apontam que estes caracteres mudam linearmente entre sulphureus e rufus de acordo com a distância ao longo de uma gradiente clinal em forma de laço do Oeste Amazônico até o Escudo das Guianas, conectado pela zona de contato de Arapiuns, sugerindo isolamento por distância. Isto sugere um remanescente de um padrão de espécie em anel. Além disso, dois espécimes com possível mistura de caracteres foram de fato encontrados no alto Rio Negro e Pantepui, onde se espera que T. r. rufus e T. r. sulphureus entrem em contato, fechando o anel efetivamente. Ainda é necessário testar se Trogon rufus constitui uma espécie em anel válida, preferencialmente usando dados moleculares, mas este caso ilustra claramente que a distinção entre variação clinal e espécie em anel é uma questão de grau e não de tipo, com a formação de espécie em anel necessariamente passando por um estágio clinal sem sobreposição entre os grupos terminais. Nós assim sugerimos o conceito de espécie em laço, onde as formas terminais não se sobrepõem, mas são ligadas através de uma série de populações onde há fluxo gênico. Parece provável que estes padrões são mais amplamente distribuídos na Amazônia do que é sabido atualmente devido a uma propensão à variação clinal e especiação parapátrica causada por sua grande extensão geográfica e abundância de barreiras geográficas semipermeáveis. Em relação a população do Centro de Endemismo Pernambuco, os poucos registros sugerem que esta é uma unidade taxonômica válida. Este grupo apresenta uma combinação única de canto muito similar ao de T. r. sulphureus, devido à alta frequência da nota introdutória e pronunciada modulação descendente ao longo do canto principal, com uma maior amplitude da frequência, combinada a maior tamanho, bico serrilhado, e anel perioftálmico azul, mas isso requer confirmação. Este caso demanda atenção urgente, já que a população remanescente é muito pequena e de distribuição restrita ao município de Murici, em Alagoas.
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Kivelä, S. M. (Sami Mikael). "Evolution of insect life histories in relation to time constraints in seasonal environments:polymorphism and clinal variation". Doctoral thesis, Oulun yliopisto, 2011. http://urn.fi/urn:isbn:9789514293788.
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Abstract Both the length of the season that is favourable for insect growth and reproduction and the number of generations emerging per season (voltinism) increase with decreasing latitude. Thus, time constraints on reproduction and juvenile development decrease with decreasing latitude, except where voltinism changes and time constraints suddenly increase as the season must be shared with one more generation. I studied the evolution of insect life histories in relation to time constraints from two perspectives: polymorphism and clinal variation. Life history polymorphism in seasonal environments was studied with the butterfly Pieris napi that has discrete life history strategies, and polymorphic natural populations. Experimental studies showed that asymmetric intraspecific larval competition and divergent timing of reproduction between the strategies may promote the maintenance of polymorphism. A simulation model showed that the divergent timing of reproduction between the strategies is sufficient to maintain polymorphism even in the absence of intraspecific competition. Clinal variation was studied empirically with four geometrid moths (Cabera exanthemata, Cabera pusaria, Chiasmia clathrata and Lomaspilis marginata) and generally in theory. Due to latitudinal saw-tooth variation in time constraints, traditional theory predicts a saw-tooth cline in body size and development time. A common garden experiment with the four geometrid moths did not support the traditional theory even when a saw-tooth cline in body size was found, suggesting that the theory is based on unrealistic assumptions. A theoretical analysis showed that reproductive effort should be high in populations under intense time constraints and low in populations experiencing no time constraints, resulting in a saw-tooth cline. In the four geometrid moths, support for these predictions was found, although the observed clinal variation deviated from the predicted pattern. The results imply that clinal variation is expected in almost any continuous life history trait, whereas polymorphism of different strategies may emerge when life histories fall into discrete categories. When inferring the evolution of a single trait, complex interdependencies among several traits should be considered, as well as the possibility that the time constraints are not similar for each generation in multivoltine populationsTiivistelmä Hyönteisten kasvu ja kehitys ovat pääsääntöisesti mahdollisia vain kesän aikana. Etelään päin mentäessä kesä pitenee, ja saman kesän aikana kehittyvien hyönteissukupolvien määrä kasvaa. Kesän pituus aiheuttaa lisääntymiseen ja toukkien kasvuun kohdistuvan aikarajoitteen, joka heikkenee etelään päin siirryttäessä. Aikarajoite kuitenkin tiukkenee siellä, missä yksi uusi sukupolvi ehtii juuri kehittymään saman kesän aikana, sillä kesä on nyt jaettava useamman sukupolven kesken. Väitöstyössä tarkastelin hyönteisten elinkierto-ominaisuuksien evoluutiota suhteessa aikarajoitteisiin sekä diskreetin että jatkuvan muuntelun näkökulmista. Diskreettiä muuntelua tutkin lanttuperhosella (Pieris napi), jolla esiintyy diskreettejä elinkiertostrategioita. Kokeellisesti osoitin, että toukkien välinen kilpailu on epäsymmetristä, mikä yhdessä eri elinkiertostrategioiden erilaisen lisääntymisen ajoittumisen kanssa voi ylläpitää diskreettiä muuntelua. Simulaatiomalli osoitti, että erilaiset elinkiertostrategiat voivat säilyä populaatiossa pelkästään niiden erilaisen lisääntymisen ajoittumisen ansiosta. Elinkierto-ominaisuuksien jatkuvaa muuntelua tutkin neljän mittariperhosen (Cabera exanthemata, Cabera pusaria, Chiasmia clathrata ja Lomaspilis marginata) avulla ja teoreettisesti yleisellä tasolla. Aikaisempi teoria ennustaa ruumiinkoon ja kehitysajan muuntelevan sahalaitakuvion mukaisesti siirryttäessä pohjoisesta etelään, koska aikarajoitteet muuntelevat samalla tavalla. Tämä teoria perustunee epärealistisiin oletuksiin, koska kokeelliset tulokset eivät tukeneet teoriaa silloinkaan, kun mittariperhosten ruumiinkoko muunteli ennustetulla tavalla. Teoreettinen tutkimus osoitti, että myös lisääntymispanostuksen tulisi muunnella sahalaitakuvion mukaisesti suhteessa kesän pituuteen siten, että se on korkeimmillaan siellä, missä aikarajoitteet ovat tiukat. Mittariperhosten tutkiminen antoi jossain määrin tukea tälle ennusteelle. Tulosten perusteella jatkuvaa maantieteellistä muuntelua ennustetaan elinkierto-ominaisuuksille, jotka muuntelevat jatkuvalla asteikolla. Erilaiset elinkiertostrategiat voivat sen sijaan säilyä populaatiossa, jos elinkierto-ominaisuuksien muuntelu on diskreettiä. Eri ominaisuuksien monimutkaiset vuorovaikutukset sekä eri sukupolvien mahdollisesti kokemat erilaiset aikarajoitteet olisi syytä tuntea, kun tarkastelun kohteena on yksittäisen ominaisuuden evoluutio
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Lobo, Nina L. "Clinal variation at putatively adaptive polymorphisms in mature populations of Sitka spruce (Picea sitchensis (Bong.) Carr.)". Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/34558.
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Common garden experiments in widely distributed tree species have demonstrated that phenotypic traits timing of bud set exhibit clinal variation across provenance climatic and geographic gradients, emphasizing the importance of these traits in local adaptation. With rapid advances in molecular techniques, spatial patterns of genomic variation underlying these traits can also be studied. Here I assess whether 17 putatively adaptive single nucleotide polymorphisms (SNPs) previously shown to be statistically associated with cold adaptation phenotypes vary clinally along a temperature gradient in natural, mature populations of Sitka spruce (Picea sitchensis). I also test the hypothesis that clinal strength is stronger in mature spruce populations than in seedling populations due to selection.
Regressions were run for each of the 17 SNPs with logit-transformed major allele frequency as the dependent variable and provenance mean annual temperature (MAT) as the independent variable. Next, differences in strength of clines between mature and seedling populations were estimated for each SNP separately and for the 17 SNPs as a group. Finally, I ran two alternate analyses – a full analysis that included all seedling populations and a truncated analysis that limited the range of MAT observed in seedling populations to match that of mature populations.
My results vary between the full and truncated analyses. In seedlings, the full analysis revealed clines in 11 SNPs (65%) compared to six SNPs (35%) in the truncated analysis. Mature populations had significant clines for five SNPs (29%). For the full analysis, the group test supported the one-sided hypothesis that mature populations have significantly steeper clines than seedlings across SNPs (P=0.027).
Parallel clines in seedling and mature populations were observed for a subset of the SNPs, which strengthens their importance for local adaptation. However, low power limited my ability to make conclusive statements about differences in clinal strength between mature and seedling populations. While most SNPs were present in most populations, I also observed that the northern, disjunct population of Kodiak Island, AK was fixed for the highest proportion of SNPs (59%). This suggests that this recently founded population may lack adaptive diversity to respond to rapid climate change in the future.
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Chen, Jun. "Conifer Evolution, from Demography and Local Adaptation to Evolutionary Rates : Examples from the Picea genus". Doctoral thesis, Uppsala universitet, Växtekologi och evolution, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-177482.
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Evolutionary process can be inferred at three different levels: the species level, the population level and the molecular level. In this thesis, I applied approaches at these three levels and aimed to get a comprehensive picture of conifer evolution, from speciation and demography to geographic variation and local adaptation, and then to the molecular evolution of proteins and small regulatory RNAs. Spruce species have been observed to possess a large number of trans-species shared polymorphisms. Using an “Isolation with migration” model, we found that the large effective population size of spruce retained these shared polymorphisms, inheriting them from the common ancestor. Post-divergence gene flow only existed between Picea abies and P. glauca, and between P. wilsonii and P. schrenkiana. The combination of Tajima’s D and Fay & Wu’s H at most of loci suggested an ancient and severe bottleneck for most species except P. breweriana. Furthermore, I investigated the effect of local selection in two parallel clines, which is one of the major forces that can cause divergence or even speciation. The timing of bud set and growth cessation was found correlated with latitude in populations of P. abies and P. obovata. Using allele frequency spectrum analyses we identified three genes under local selection in both species including two circadian-clock genes GI and PRR7, and one photoperiodic gene FTL2. This indicated that parallel evolution could occur through groups of genes within related pathways. Clinal variation at expression level provided stronger evidence of selection in FTL2, which has previously been associated with bud set in P. abies. Finally we focused on the molecular evolution of mRNA and small regulatory RNAs in P. abies. With the help of Next-Generation sequencing, we have achieved in spruce the first de novel assembly of the needle transcriptome and a preliminary characterization of sRNA populations. Along with features common in plants, spruce also exhibited novelties in many aspects including lower substitution rate and protein evolutionary rate, dominance of 21-nt sRNA, and a large proportion of TIR-NBS-LRR genes as sRNA sources and targets.
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Speer, William D. "Systematics of Eastern North American Bracken Fern". Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/36715.
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The cosmopolitan Pteridium aquilinum (L.)
Kuhn is widespread throughout eastern
North American, where it is represented
primarily by Tryon's (1941) var. latiusculum
(Desv.) Underw. and var. pseudocaudatum
(Clute) Heller. The taxonomy of Pteridium is
controversial. Fourteen isozyme loci and 12
morphological characters were used to
assess the taxonomic relationship of these
two varieties. Isozyme data indicated a high
mean genetic identity (I = 0.976) between
eleven bracken populations. Strong patterns
of geographic variation for isozyme allele
frequencies were also observed. The isozyme
results did not separate the two taxa.
Numerical analysis of the morphology
distinguished the two taxa when the
qualitative characters were used alone or in
conjunction with some of the quantitative
traits. All qualitative characters differed
significantly between the two taxa. No
perceptible geographic pattern of variation
was observed. Morphological distinctiveness
was maintained even in those localities where
both taxa were present, with few or no
intermediates being found. Isozyme evidence
suggestive of gene flow between the two
varieties was found at Greensboro, NC,
where the two morphotypes were easily
recognizable. The isozyme evidence strongly
indicates conspecificity, while the
morphological evidence supports their status
at the varietal level.Master of Science
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Olsson, Jenny. "Genetic diversity and hardiness in Scots pine from Scandinavia to Russia". Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-160222.
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The postglacial recolonization of northern Europe supposedly originated from Western Europe and the Russian Plain, however, recent molecular and macrofossil-based investigations suggest that the history may be more complex than previously thought. This study aims to investigate the genetic diversity and population structure of Scots pine from Scandinavia to Russia to re-evaluate its recolonization history, and to examine whether the pattern of spatial genetic diversity has any adaptive significance. Populations ranging from Norway to Russia were sampled and genotyped using genotyping-by-sequencing. The seedlings were freeze tested to provide an average degree of hardiness for every population. Eight hundred and thirty-two seedlings were analyzed, and 6,034 SNPs were recovered in these individuals after stringent filtering. Population structure was investigated using fastStructure and differentiation between populations was estimated with pairwise FST and analysis of molecular variance (AMOVA) to assess the genetic variability. Genetic diversity was measured as observed heterozygosity, H0, in populations, clusters and overall. Two genetic clusters were detected in the samples, one in Norway and Sweden and one in Russia. These clusters are weakly differentiated (FST = 0.01202) with only 0.66 % variation between them. Highest variation was found within populations (98.8 %) and the overall genetic diversity for all populations was high (Ho = 0.2573). The weak differentiation and high diversity are indicative of extensive gene flow between populations in this species. The composition of the clusters across the sampled area suggests a westward recolonization from the Russian Plain into Scandinavia, and a possible local origin of another polymorphism in Norway and Sweden. No clear relationship between cold hardiness and genetic variation was detected. The clinal variation in cold hardiness reflects local adaptation, and the difference between genetic and phenotypic variation is likely due to epigenetic regulation or polygenic inheritance. More extensive genome scan is needed to understand the genetic basis of local adaptation.
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Lovat, Christie-Anna. "Clinal variation and phenology in two conspecifics of Phragmites australis (Cav.) Trin. Ex Steud in Northeastern North America: implications for current management and future climate change". Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=119468.
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Within native and non-native plant species, the production of viable seeds can both promote range expansion and facilitate rapid climatic adaptations through the selection of adapted phenotypes. The success of sexual reproduction in many plant species has been linked to a critical level of accumulated growing degree-days (GDDs) throughout the season. However GDDs are often limited in northern climates. With climate change forecasted to cause temperature increases in many northern areas, GDDs are likely to increase and there exists the potential for some species currently limited by a lack of GDDs to undergo increases in sexual reproduction and ultimately range expansion. Field studies and in vitro germination trials were used to test the relationship between seasonal GDDs and development, height and sexual reproduction in an established invasive non-native species, Phragmites australis (Cav.) Trin. Ex Steud. (haplotype M) and its native conspecific, P. australis subsp. americanus. During the 2012 season, 29 populations were monitored within five isotherms along a1000-km long latitudinal gradient from New Jersey (USA) to Alma (Quebec). As seasonal GDDs decreased, non-native P. australis were on average shorter, required fewer GDDs to develop, and produced fewer viable seeds per floret. Within isotherms, native P. australis were shorter and developed earlier than non-native P. australis, and also generally produced more seeds per floret. Overall the response of native P. australis was not related to seasonal GDDs. Over the climate gradient of the study area it appears that a lack of GDDs is currently limiting the expansion of non-native P. australis through seed dispersal at the edge of its range. As local temperatures and ultimately GDDs increase with climate change, the adaptive response non-native P. australis has to climate will likely allow the species to rapidly expand its range to take advantage of newly available climatic niches.La reproduction sexuée et la production subséquente de graines viables peuvent faciliter la dispersion d'espèces végétales indigènes ou non indigènes/envahissantes dans de nouvelles régions ainsi que possiblement une adaptation rapide à des conditions changeantes grâce à la sélection de phénotypes appropriés. Le succès de la reproduction sexuée pour de nombreuses espèces végétales a été lié à une accumulation critique de degrés-jours de croissance (DJCs) durant la saison. Cependant les DJCs sont souvent limités dans les climats nordiques. Avec les changements climatiques et les températures qui augmenteront particulièrement vers le nord, le DJCs sont susceptibles d'augmenter et des espèces actuellement limitées par un manque de DJCs pourraient voir une augmentation de leur reproduction sexuée et éventuellement une extension de leur aire de répartition. Un suivi sur le terrain et des essais de germination ont été utilisés pour tester la relation entre les DJCs saisonniers et le développement, la hauteur et la reproduction sexuée d'une espèce envahissante non indigène, Phragmites australis (Cav.) Trin. Ex Steud. (M haplotype) et sa congénère indigène, P. australis subsp. americanus. Durant la saison 2012, 29 populations ont été suivies dans cinq isothermes le long d'un gradient latitudinal de 1000 km du New Jersey (États-Unis) à Alma (Québec). Le P. australis non indigène était en moyenne plus court, requerrait moins de DJCs pour produire des inflorescences, et produisait moins de graines viables avec une diminution des DJCs saisonniers. Pour un même isotherme, le P. australis indigène était plus court et se développait plus tôt que le P. australis non indigène, et aussi généralement produisait plus de graines. Globalement, la réponse du P. australis indigène n'était pas liée au DJCs saisonniers. Le long du gradient climatique de la zone étudiée, il semble que le manque de DJCs limite actuellement l'expansion par dispersion de graines du P. australis non indigène, tout en ayant peu ou pas d'effet sur le P. australis indigène. Une production de graines accrue par les changements climatiques pourrait permettre au P. australis envahissant d'exploiter des niches climatiques nouvellement disponibles.
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Olsson, Katarina. "Population differentiation in Lythrum salicaria along a latitudinal gradient". Doctoral thesis, Umeå : Univ, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-364.
Pełny tekst źródłaKsiążki na temat "Clinal variation"
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Lasjaunias, Pierre, Alejandro Berenstein i Karel G. ter Brugge. Clinical Vascular Anatomy and Variations. Berlin, Heidelberg: Springer Berlin Heidelberg, 2001. http://dx.doi.org/10.1007/978-3-662-10172-8.
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Iwanaga, Joe, i R. Shane Tubbs, red. Anatomical Variations in Clinical Dentistry. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-319-97961-8.
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United States. Agency for Healthcare Research and Quality., red. Demographic and clinical variations in health status. Rockville, MD: U.S. Dept. of Health and Human Services, Public Health Service, Agency for Healthcare Research and Quality, 2005.
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Genetic factors in drug therapy: Clinical and molecular pharmacogenetics. Cambridge [England]: Cambridge University Press, 1993.
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Darde, Jean-Noël. Où partir? en 2007: Saisons & climats. Paris: Hachette Tourisme, 2007.
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Grand, Walter. Vasculature of the brain and cranial base: Variations in clinical anatomy. New York: Thieme, 1998.
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Lüdinghausen, M. von. The clinical anatomy of coronary arteries. Berlin: Springer, 2003.
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The clinical anatomy of coronary arteries. Berlin: Springer, 2003.
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Où et quand partir?: En 2011. Paris: Hachette, 2010.
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Darde, Jean-Noël. Où partir? en 2006: Saisons & climats. [Paris]: Hachette, 2005.
Znajdź pełny tekst źródłaCzęści książek na temat "Clinal variation"
1
Mucina, Ladislav. "Vicariance and Clinal Variation in Synanthropic Vegetation". W Quantitative approaches to phytogeography, 263–76. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-009-2063-7_9.
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Wyandt, Herman E., i Vijay S. Tonk. "Clinical Populations". W Human Chromosome Variation: Heteromorphism and Polymorphism, 43–50. Dordrecht: Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-94-007-0896-9_4.
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Wyandt, Herman E., Golder N. Wilson i Vijay S. Tonk. "Clinical Populations". W Human Chromosome Variation: Heteromorphism, Polymorphism and Pathogenesis, 47–56. Singapore: Springer Singapore, 2017. http://dx.doi.org/10.1007/978-981-10-3035-2_4.
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Qin, Xue. "Factors Associated with Variation". W Clinical Molecular Diagnostics, 91–95. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-1037-0_7.
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Huang, Zhengxing, Xudong Lu, Chenxi Gan i Huilong Duan. "Variation Prediction in Clinical Processes". W Artificial Intelligence in Medicine, 286–95. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-22218-4_36.
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Bruhn, John G., i Howard M. Rebach. "Ethnic Variations in Caregiving". W Clinical Sociology: Research and Practice, 97–121. Dordrecht: Springer Netherlands, 2014. http://dx.doi.org/10.1007/978-94-017-8857-1_8.
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Lasjaunias, Pierre, Alejandro Berenstein i Karel G. ter Brugge. "General Introduction". W Clinical Vascular Anatomy and Variations, 1–72. Berlin, Heidelberg: Springer Berlin Heidelberg, 2001. http://dx.doi.org/10.1007/978-3-662-10172-8_1.
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Lasjaunias, Pierre, Alejandro Berenstein i Karel G. ter Brugge. "Spinal and Spinal Cord Arteries and Veins". W Clinical Vascular Anatomy and Variations, 73–164. Berlin, Heidelberg: Springer Berlin Heidelberg, 2001. http://dx.doi.org/10.1007/978-3-662-10172-8_2.
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Lasjaunias, Pierre, Alejandro Berenstein i Karel G. ter Brugge. "Craniocervical Junction". W Clinical Vascular Anatomy and Variations, 165–260. Berlin, Heidelberg: Springer Berlin Heidelberg, 2001. http://dx.doi.org/10.1007/978-3-662-10172-8_3.
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Lasjaunias, Pierre, Alejandro Berenstein i Karel G. ter Brugge. "Skull Base and Maxillofacial Region". W Clinical Vascular Anatomy and Variations, 261–385. Berlin, Heidelberg: Springer Berlin Heidelberg, 2001. http://dx.doi.org/10.1007/978-3-662-10172-8_4.
Pełny tekst źródłaStreszczenia konferencji na temat "Clinal variation"
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HERVE, Lionel, Cédric Allier, Pierre Blandin, Fabrice Navarro, Mathilde Menneteau, Thomas Bordy, Olivier Cioni i Sophie Morales. "Multispectral Total-variation Reconstruction Applied to Lens-free Microscopy". W Clinical and Translational Biophotonics. Washington, D.C.: OSA, 2018. http://dx.doi.org/10.1364/translational.2018.jth3a.28.
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Feng, Jinchao, Yinan Li, Zhe Li, Zhonghua Sun i Kebin Jia. "A Reconstruction Algorithm for Bioluminescence Tomography Based on Sparse and Total Variation Regularizations". W Clinical and Translational Biophotonics. Washington, D.C.: OSA, 2018. http://dx.doi.org/10.1364/translational.2018.jtu3a.28.
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Zhao, Mingjun, Chong Huang, Li Chen, Jeffrey Radabaugh, Rony Aouad, Nneamaka Agochukwu, Lesley Wong i Guoqiang Yu. "Intraoperative Assessment of Blood Flow Variations in Tissue Flaps Using Noncontact Diffuse Correlation Spectroscopy". W Clinical and Translational Biophotonics. Washington, D.C.: OSA, 2018. http://dx.doi.org/10.1364/translational.2018.cf3b.6.
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DE LA VEGA, FRANCISCO M., MARTIN KREITMAN i ISSAC S. KOHANE. "HUMAN GENOME VARIATION: LINKING GENOTYPES TO CLINICAL PHENOTYPES". W Proceedings of the Pacific Symposium. WORLD SCIENTIFIC, 2000. http://dx.doi.org/10.1142/9789814447362_0001.
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Connors, GR, B. Richardson, G. Hong, L. Christopher-Stine i SK Danoff. "Clinical, Radiographic, and Pathologic Variation in Antisynthetase Syndrome." W American Thoracic Society 2009 International Conference, May 15-20, 2009 • San Diego, California. American Thoracic Society, 2009. http://dx.doi.org/10.1164/ajrccm-conference.2009.179.1_meetingabstracts.a3939.
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Kadowaki, Hiroko. "Temporal Variation Characteristics of Analysis Accuracy in Two-Dimensional Ultrasonic-Measurement-Integrated Blood Flow Analysis". W ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-67661.
Pełny tekst źródłaStreszczenie:
A two-dimensional ultrasonic-measurement-integrated (2D-UMI) blood flow analysis system was developed for easy acquisition of an intravascular hemodynamics, which feeds back Doppler velocity obtained by an ultrasonic measurement to a numerical blood flow simulation for clinical application. In previous study, ultrasonic measurement and 2D-UMI simulation were performed to clarify the analysis accuracy for real flow field. Additionally, spatial variation characteristics of analysis accuracy was clarified by comparison of velocity vectors between 2D-UMI and 3D-CFD analysis results corresponding to an experimental flow. However, temporal variation of analysis accuracy of 2D-UMI analysis result has not been examined in spite of essential information for reduction of experimental measurement error due to speckle noise. The aim of this study was to clarify temporal variation characteristics of analysis accuracy of each velocity component obtained in 2D-UMI blood flow analysis. Comparisons of Doppler velocity V and (u, v) velocity profiles between measurement data, 2D-UMI, and 3D-CFD analysis results were performed, and their time variations were discussed. As a result, it was clarified that temporal variation of Doppler velocity error for measurement data became larger with increasing feedback gain. Temporal variations of u and v velocity component errors for 3D-CFD analysis result showed the same tendency as that of Doppler velocity in feedback gain.
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DE LA VEGA, FRANCISCO M., ISAAC S. KOHANE, JULIE A. SCHNEIDER i J. CLAIBORNE STEPHENS. "HUMAN GENOME VARIATION: DISEASE, DRUG RESPONSE, AND CLINICAL PHENOTYPES". W Proceedings of the Pacific Symposium. WORLD SCIENTIFIC, 2001. http://dx.doi.org/10.1142/9789812799623_0001.
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Kim, Jungsil, i Seungik Baek. "Spatial Variations in the Mechanical Properties of the Porcine Thoracic Aorta". W ASME 2011 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2011. http://dx.doi.org/10.1115/sbc2011-53329.
Pełny tekst źródłaStreszczenie:
Characterization of the mechanical properties of a blood vessel is essential in understanding the progression of a vascular disease and for computational studies of vascular adaptation. For example, stiffness of vascular tissue is one of the major indicators to diagnose the vascular disease and make a clinical decision. Although previous studies reported the heterogeneity of the mechanical properties of arterial wall along the arterial tree [2], little was taken account for its circumferential variations. With the lack of experimental studies for investigating the circumferential variation, the aortic wall is typically assumed to have uniform deformation. Our previous study, however, has observed that there are circumferential variations in aortic wall stress and stiffness [1]. In addition to our previous study, we investigate further regional variations of the porcine thoracic aorta in both circumferential and longitudinal directions during the inflation test. Hence, we additionally test the distal thoracic aorta at each anterior and posterior side, respectively, and compare with the proximal thoracic aorta.
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Du, Gang, Zhibin Jiang, Xiaodi Diao, Yan Ye i Yang Yao. "Modelling, variation monitoring, analyzing, reasoning for intelligently reconfigurable Clinical Pathway". W 2009 IEEE/INFORMS International Conference on Service Operations, Logistics and Informatics (SOLI). IEEE, 2009. http://dx.doi.org/10.1109/soli.2009.5203909.
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Sundararajan, K., A. O'Connell, C. Thompson i A. Flabouris. "Responding to Clinical Deterioration: Diurnal Variation in Afferent Limb Failure". W American Thoracic Society 2019 International Conference, May 17-22, 2019 - Dallas, TX. American Thoracic Society, 2019. http://dx.doi.org/10.1164/ajrccm-conference.2019.199.1_meetingabstracts.a4354.
Pełny tekst źródłaRaporty organizacyjne na temat "Clinal variation"
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Nicault, A., É. Boucher, D. Tapsoba i Y. Bégin. Influence des variations interannuelles du climat sur la croissance radiale des épinettes noires. Natural Resources Canada/CMSS/Information Management, 2021. http://dx.doi.org/10.4095/328075.
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Bain, Luchuo Engelbert, i Darja Dobermann. Malaria, HIV and TB in the Democratic Republic of the Congo: Epidemiology, Disease Control Challenges and Interventions. Institute of Development Studies (IDS), marzec 2022. http://dx.doi.org/10.19088/k4d.2022.034.
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Malaria, human immune deficiency virus (HIV) and tuberculosis (TB) are leading causes of death and public health threat to millions in Democratic Republic of Congo (DRC). The DRC is the second most malaria affected sub-Saharan African country after Nigeria, with malaria being the leading cause of death in children under 5 years (Lechthaler et al., 2019). The HIV prevalence in the country in the adult population stands at 1%, with extensive variations by region (UNAIDS, 2021c). The DRC is considered a high burden country for TB and HIV infection (Linguissi et al., 2017). This rapid review emphasizes significant elements of the epidemiology of malaria, HIV, and TB in DRC, as well as limitations in prevention, detection, and treatment, and examines a few interventions that aim to address these limitations. Evidence utilised is a mixture of the most recent grey literature NGO (programme reports and related documents) literature supplemented by peer reviewed academic literature from the past five years and national survey data when available. Although the clinical disease aspects of malaria, HIV and TB are well-researched there is less research available on socio-demographic variation, disease control challenges and interventions targeting these in the DRC. This is part of a series of reports looking into Epidemiology of Malaria, human immune deficiency virus (HIV) and tuberculosis (TB) across a set of African Nations.
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Newman-Toker, David E., Susan M. Peterson, Shervin Badihian, Ahmed Hassoon, Najlla Nassery, Donna Parizadeh, Lisa M. Wilson i in. Diagnostic Errors in the Emergency Department: A Systematic Review. Agency for Healthcare Research and Quality (AHRQ), grudzień 2022. http://dx.doi.org/10.23970/ahrqepccer258.
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Objectives. Diagnostic errors are a known patient safety concern across all clinical settings, including the emergency department (ED). We conducted a systematic review to determine the most frequent diseases and clinical presentations associated with diagnostic errors (and resulting harms) in the ED, measure error and harm frequency, as well as assess causal factors. Methods. We searched PubMed®, Cumulative Index to Nursing and Allied Health Literature (CINAHL®), and Embase® from January 2000 through September 2021. We included research studies and targeted grey literature reporting diagnostic errors or misdiagnosis-related harms in EDs in the United States or other developed countries with ED care deemed comparable by a technical expert panel. We applied standard definitions for diagnostic errors, misdiagnosis-related harms (adverse events), and serious harms (permanent disability or death). Preventability was determined by original study authors or differences in harms across groups. Two reviewers independently screened search results for eligibility; serially extracted data regarding common diseases, error/harm rates, and causes/risk factors; and independently assessed risk of bias of included studies. We synthesized results for each question and extrapolated U.S. estimates. We present 95 percent confidence intervals (CIs) or plausible range (PR) bounds, as appropriate. Results. We identified 19,127 citations and included 279 studies. The top 15 clinical conditions associated with serious misdiagnosis-related harms (accounting for 68% [95% CI 66 to 71] of serious harms) were (1) stroke, (2) myocardial infarction, (3) aortic aneurysm and dissection, (4) spinal cord compression and injury, (5) venous thromboembolism, (6/7 – tie) meningitis and encephalitis, (6/7 – tie) sepsis, (8) lung cancer, (9) traumatic brain injury and traumatic intracranial hemorrhage, (10) arterial thromboembolism, (11) spinal and intracranial abscess, (12) cardiac arrhythmia, (13) pneumonia, (14) gastrointestinal perforation and rupture, and (15) intestinal obstruction. Average disease-specific error rates ranged from 1.5 percent (myocardial infarction) to 56 percent (spinal abscess), with additional variation by clinical presentation (e.g., missed stroke average 17%, but 4% for weakness and 40% for dizziness/vertigo). There was also wide, superimposed variation by hospital (e.g., missed myocardial infarction 0% to 29% across hospitals within a single study). An estimated 5.7 percent (95% CI 4.4 to 7.1) of all ED visits had at least one diagnostic error. Estimated preventable adverse event rates were as follows: any harm severity (2.0%, 95% CI 1.0 to 3.6), any serious harms (0.3%, PR 0.1 to 0.7), and deaths (0.2%, PR 0.1 to 0.4). While most disease-specific error rates derived from mainly U.S.-based studies, overall error and harm rates were derived from three prospective studies conducted outside the United States (in Canada, Spain, and Switzerland, with combined n=1,758). If overall rates are generalizable to all U.S. ED visits (130 million, 95% CI 116 to 144), this would translate to 7.4 million (PR 5.1 to 10.2) ED diagnostic errors annually; 2.6 million (PR 1.1 to 5.2) diagnostic adverse events with preventable harms; and 371,000 (PR 142,000 to 909,000) serious misdiagnosis-related harms, including more than 100,000 permanent, high-severity disabilities and 250,000 deaths. Although errors were often multifactorial, 89 percent (95% CI 88 to 90) of diagnostic error malpractice claims involved failures of clinical decision-making or judgment, regardless of the underlying disease present. Key process failures were errors in diagnostic assessment, test ordering, and test interpretation. Most often these were attributed to inadequate knowledge, skills, or reasoning, particularly in “atypical” or otherwise subtle case presentations. Limitations included use of malpractice claims and incident reports for distribution of diseases leading to serious harms, reliance on a small number of non-U.S. studies for overall (disease-agnostic) diagnostic error and harm rates, and methodologic variability across studies in measuring disease-specific rates, determining preventability, and assessing causal factors. Conclusions. Although estimated ED error rates are low (and comparable to those found in other clinical settings), the number of patients potentially impacted is large. Not all diagnostic errors or harms are preventable, but wide variability in diagnostic error rates across diseases, symptoms, and hospitals suggests improvement is possible. With 130 million U.S. ED visits, estimated rates for diagnostic error (5.7%), misdiagnosis-related harms (2.0%), and serious misdiagnosis-related harms (0.3%) could translate to more than 7 million errors, 2.5 million harms, and 350,000 patients suffering potentially preventable permanent disability or death. Over two-thirds of serious harms are attributable to just 15 diseases and linked to cognitive errors, particularly in cases with “atypical” manifestations. Scalable solutions to enhance bedside diagnostic processes are needed, and these should target the most commonly misdiagnosed clinical presentations of key diseases causing serious harms. New studies should confirm overall rates are representative of current U.S.-based ED practice and focus on identified evidence gaps (errors among common diseases with lower-severity harms, pediatric ED errors and harms, dynamic systems factors such as overcrowding, and false positives). Policy changes to consider based on this review include: (1) standardizing measurement and research results reporting to maximize comparability of measures of diagnostic error and misdiagnosis-related harms; (2) creating a National Diagnostic Performance Dashboard to track performance; and (3) using multiple policy levers (e.g., research funding, public accountability, payment reforms) to facilitate the rapid development and deployment of solutions to address this critically important patient safety concern.
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Ni, Jiachun, Qiong Jiang, Gang Mao, Yi Yang, Qin Wei, Changcheng Hou, Xiangdong Yang, Wenbin Fan i Zengjin Cai. The effectiveness and safety of acupuncture for constipation associated with Parkinson’s disease: Protocol for a systematic review and meta-analysis. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, luty 2022. http://dx.doi.org/10.37766/inplasy2022.2.0091.
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Review question / Objective: Is acupuncture a safe and effective therapy for constipation associated with Parkinson’s disease? Our aim is to assess the effectiveness and safety of acupuncture for constipation associated with PD and give guidance to future research direction. Condition being studied: Parkinson’s disease (PD) is a prevalent degenerative disease of nervous system characterized mainly by static tremor, bradykinesia, myotonia, postural gait disorders and other non-motor symptoms. According to variations on race, ethnicity, age and sex, the incidence of PD ranges from 8 to 20.5 per 100, 000 individuals annually. One global research shows that there were 6.1 million individuals suffer from PD in 2016 and will be 12 million patients around the world. According to several outcomes of case-control studies, the prevalence of constipation in PD varies from 28% to 61%. Constipation, as a common gastrointestinal disease which refers to the clinical presentation of reduced spontaneous complete bowel movement, dyschezia, feeling of incomplete defecation and outlet obstruction, is demonstrated to antedate the motor symptom and it's severity is related to the progression of PD. Acupuncture has been proved to act on the pathogenesis of constipation associated with PD. The proposed systematic review we're about to present is the first advanced evidence-based medical evidence in this area.
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Levisohn, Sharon, Mark Jackwood i Stanley Kleven. New Approaches for Detection of Mycoplasma iowae Infection in Turkeys. United States Department of Agriculture, luty 1995. http://dx.doi.org/10.32747/1995.7612834.bard.
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Mycoplasma iowae (Mi) is a pathogenic avian mycoplasma which causes mortality in turkey embryos and as such has clinical and economic significance for the turkey breeder industry. Control of Mi infection is severely hampered by lack of adequate diagnostic tests, together with resistance to most antibiotics and resilience to environment. A markedly high degree of intra-species antigenic variation also contributes to difficulties in detection and control of infection. In this project we have designed an innovative gene-based diagnostic test based on specific amplification of the 16S rRNA gene of Mi. This reaction, designed Multi-species PCR-RFLP test, also amplifies the DNA of the pathogenic avian mycoplasmas M. gallisepticum (Mg) and M. synoviae (Ms). This test detects DNA equivalent to about 300 cfu Mi or either of the other two target mycoplasmas, individually or in mixed infection. It is a quick test, applicable to a wide variety of clinical samples, such as allantoic fluid or tracheal or cloacal swab suspensions. Differential diagnosis is carried out by gel electro-phoresis of the PCR amplicon digested with selected restriction enzymes (Restriction Fragment Length Polymorphism). This can also be readily accomplished by using a simple Dot-Blot hybridization assay with digoxigenin-labeled oligonucleotide probes reacting specifically with unique Mi, Mg or Ms sequences in the PCR amplicon. The PCR/OLIGO test increased sensitivity by at least 10-fold with a capacity for rapid testing of large numbers of samples. Experimental infection trials were carried out to evaluate the diagnostic tools and to study pathogenesis of Mi infection. Field studies and experimental infection of embryonated eggs indicated both synergistic and competitive interaction of mycoplasma pathogens in mixed infection. The value of the PCR diagnostic tests for following the time course of egg transmission was shown. A workable serological test (Dot Immunobinding Assay) was also developed but there was no clear-cut evidence that infected turkeys develop an immune response. Typing of a wide spectrum of Mi field isolates by a variety of gene-based molecular techniques indicated a higher degree of genetic homogeneity than predicted on the basis of the phenotypic variability. All known strains of Mi were detected by the method developed. Together with an M. meleagridis-PCR test based on the same gene, the Multi-species PCR test is a highly valuable tool for diagnosis of pathogenic mycoplasmas in single or mixed infection. The further application of this rapid and specific test as a part of Mi and overall mycoplasma control programs will be dependent on developments in the turkey industry.
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Schwartz, Bertha, Vaclav Vetvicka, Ofer Danai i Yitzhak Hadar. Increasing the value of mushrooms as functional foods: induction of alpha and beta glucan content via novel cultivation methods. United States Department of Agriculture, styczeń 2015. http://dx.doi.org/10.32747/2015.7600033.bard.
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During the granting period, we performed the following projects: Firstly, we differentially measured glucan content in several pleurotus mushroom strains. Mushroom polysaccharides are edible polymers that have numerous reported biological functions; the most common effects are attributed to β-glucans. In recent years, it became apparent that the less abundant α-glucans also possess potent effects in various health conditions. In our first study, we explored several Pleurotus species for their total, β and α-glucan content. Pleurotuseryngii was found to have the highest total glucan concentrations and the highest α-glucans proportion. We also found that the stalks (stipe) of the fruit body contained higher glucan content then the caps (pileus). Since mushrooms respond markedly to changes in environmental and growth conditions, we developed cultivation methods aiming to increase the levels of α and β-glucans. Using olive mill solid waste (OMSW) from three-phase olive mills in the cultivation substrate. We were able to enrich the levels mainly of α-glucans. Maximal total glucan concentrations were enhanced up to twice when the growth substrate contained 80% of OMSW compared to no OMSW. Taking together this study demonstrate that Pleurotuseryngii can serve as a potential rich source of glucans for nutritional and medicinal applications and that glucan content in mushroom fruiting bodies can be further enriched by applying OMSW into the cultivation substrate. We then compared the immune-modulating activity of glucans extracted from P. ostreatus and P. eryngii on phagocytosis of peripheral blood neutrophils, and superoxide release from HL-60 cells. The results suggest that the anti-inflammatory properties of these glucans are partially mediated through modulation of neutrophileffector functions (P. eryngiiwas more effective). Additionally, both glucans dose-dependently competed for the anti-Dectin-1 and anti-CR3 antibody binding. We then tested the putative anti-inflammatory effects of the extracted glucans in inflammatory bowel disease (IBD) using the dextran sulfate sodium (DSS)–induced model in mice. The clinical symptoms of IBD were efficiently relieved by the treatment with two different doses of the glucan from both fungi. Glucan fractions, from either P. ostreatus or P. eryngii, markedly prevented TNF-α mediated inflammation in the DSS–induced inflamed intestine. These results suggest that there are variations in glucan preparations from different fungi in their anti-inflammatory ability. In our next study, we tested the effect of glucans on lipopolysaccharide (LPS)-induced production of TNF-α. We demonstrated that glucan extracts are more effective than mill mushroom preparations. Additionally, the effectiveness of stalk-derived glucans were slightly more pronounced than of caps. Cap and stalk glucans from mill or isolated glucan competed dose-dependently with anti-Dectin-and anti-CR-3 antibodies, indicating that they contain β-glucans recognized by these receptors. Using the dextran sulfate sodium (DSS)-inflammatory bowel disease mice model, intestinal inflammatory response to the mill preparations was measured and compared to extracted glucan fractions from caps and stalks. We found that mill and glucan extracts were very effective in downregulatingIFN-γ and MIP-2 levels and that stalk-derived preparations were more effective than from caps. The tested glucans were equally effective in regulating the number of CD14/CD16 monocytes and upregulating the levels of fecal-released IgA to almost normal levels. In conclusion, the most effective glucans in ameliorating some IBD-inflammatory associated symptoms induced by DSS treatment in mice were glucan extracts prepared from the stalk of P. eryngii. These spatial distinctions may be helpful in selecting more effective specific anti-inflammatory mushrooms-derived glucans. We additionally tested the effect of glucans on lipopolysaccharide-induced production of TNF-α, which demonstrated stalk-derived glucans were more effective than of caps-derived glucans. Isolated glucans competed with anti-Dectin-1 and anti-CR3 antibodies, indicating that they contain β-glucans recognized by these receptors. In conclusion, the most effective glucans in ameliorating IBD-associated symptoms induced by DSS treatment in mice were glucan extracts prepared from the stalk of P. eryngii grown at higher concentrations of OMSW. We conclude that these stress-induced growing conditions may be helpful in selecting more effective glucans derived from edible mushrooms. Based on the findings that we could enhance glucan content in Pleurotuseryngii following cultivation of the mushrooms on a substrate containing different concentrations of olive mill solid waste (OMSW) and that these changes are directly related to the content of OMSW in the growing substrate we tested the extracted glucans in several models. Using dextran sulfate sodium (DSS)–inflammatory bowel disease (IBD) mice model, we measured the colonic inflammatory response to the different glucan preparations. We found that the histology damaging score (HDS) resulting from DSS treatment reach a value of 11.8 ± 2.3 were efficiently downregulated by treatment with the fungal extracted glucans, glucans extracted from stalks cultivated at 20% OMSWdownregulated to a HDS value of 6.4 ± 0.5 and at 80% OMSW showed the strongest effects (5.5 ± 0.6). Similar downregulatory effects were obtained for expression of various intestinal cytokines. All tested glucans were equally effective in regulating the number of CD14/CD16 monocytes from 18.2 ± 2.7 % for DSS to 6.4 ± 2.0 for DSS +glucans extracted from stalks cultivated at 50% OMSW. We finally tested glucans extracted from Pleurotuseryngii grown on a substrate containing increasing concentrations of olive mill solid waste (OMSW) contain greater glucan concentrations as a function of OMSW content. Treatment of rat Intestinal epithelial cells (IEC-6) transiently transfected with Nf-κB fused to luciferase demonstrated that glucans extracted from P. eryngii stalks grown on 80% OMSWdownregulatedTNF-α activation. Glucans from mushrooms grown on 80% OMSW exerted the most significant reducing activity of nitric oxide production in lipopolysaccharide (LPS) treated J774A.1 murine macrophages. The isolated glucans were tested in vivo using the Dextran Sodium Sulfate (DSS) induced colitis in C57Bl/6 mice and found to reduce the histology damaging score resulting from DSS treatment. Expression of various intestinal cytokines were efficiently downregulated by treatment with the fungal extracted glucans. We conclude that the stress-induced growing conditions exerted by OMSW induces production of more effective anti-inflammatory glucans in P. eryngii stalks.