74 resultados para genetic and environmental factors
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Com o objetivo de identificar os padrões de organização das comunidades de peixes dos rios Jogui e Iguatemi nós amostramos peixes através de redes de espera trimestralmente entre Novembro/1999 e Agosto/2000. Hypostomus ancistroides e Parauchenipterus galeatus foram as espécies de peixes mais abundantes nos rios Jogui e Iguatemi, respectivamente. A variação longitudinal foi mais importante que a sazonal na determinação da composição de espécies em ambos os rios e a diferença entre estações não foi significativa. A altitude foi o fator mais importante na determinação da distribuição das espécies.
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The objectives this paper were to estimate genetic parameters and genetic and phenotypic trends of birth weight (BWT) and weights adjusted to 205 (WT205), 365 (WT365) and 550 (P550) days of age of beef buffaloes born from 1985 to 2003 in Brazil. For BWT and WT205 the model included direct and maternal genetic and maternal environment as random effects and contemporary and genetic groups as fixed effects. For WT365 and WT550 the same model was used except without direct maternal and maternal environmental effects. The genetic and phenotypic trends were estimated by regression of means of dependent variables on birth year of animals Regressions were obtained by using two methodologies: 1) linear regression; and 2) non-parametric splined regression. The direct heritability estimates were 0.09, 0.45, 0.46 and 0.58 for BWT, WT205, WT365 and WT550, respectively. The direct genetic trends from linear regression were 0.01, 0.23, 0.58 and 1.40 kg per year for PN, WT205, VVT365 and WT550, respectively (P<0.001 for all). Phenotypic trends were strongly positive while genetic trends were consistently positive but small. Genetic parameters indicate potential for increased rate of genetic change with full implementation of genetic improvement programs.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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The objective of this study was to estimate the relative effects of genetic and phenotypic factors on the efficacy and efficiency of superovulation for Holstein-Friesian cows reared in Brazil. A database, established by the Associacao Brasileira de Criadores de Bovinos da Raca Holandesa, consisting of a total of 5387 superovulations of 2941 cows distributed over 473 herds and sired by 690 bulls was used for the analysis. The records were analyzed by MTDFREML (Multiple Trait Derivative-Free Restricted Maximum Likelihood), using a repeatability animal model. The fixed effects included in the model were contemporaneous group (veterinarian, herd, year and season of the superovulation); number of semen doses; cow age; and superovulation order. The estimated repeatability of the number of the transferable embryos was low (0.13), and the estimated heritability was 0.03. These results indicate that environmental factors play a critical role in the response of a cow to a superovulation treatment. There is little evidence that future responses to superovulation by individual females can be predicted by previous treatment(s) or that superovulation response is an heritable trait.
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Foraging behavior in social wasps is important in the development of the colony and reflects an important ecological interaction between the colony and the environment. Although the social traits of the colony play a role in the foraging activities, the conditions that establish the space and time limits are mainly physical. Here, we evaluate colonies of Polybia paulista throughout one year in order to verify the foraging activities and the items collected, as well as the importance of temperature, relative humidity, and solar radiation on motivating foraging. Collection of liquids was always higher than that of solids; preys were collected all year long, and nests showed two annual episodic expansions. The linear mixed effects (LME) model used to analyze which weather factors influence the foraging showed temperature as the most influencing factor on the collection of materials. © 2011 Naila Cristina de Souza Canevazzi and Fernando Barbosa Noll.
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This study was conducted to examine the relationship among average annual productivity of the cow (PRODAM), yearling weight (YW), postweaning BW gain (PWG), scrotal circumference (SC), and stayability in the herd for at least 6 yr (STAY) of Nelore and composite beef cattle. Measurements were taken on animals born between 1980 and 2010 on 70 farms located in 7 Brazilian states. Estimates of heritability and genetic and environmental correlations were obtained by Bayesian approach with 5-trait animal models. Genetic trends were estimated by regressing means of estimated breeding values by year of birth. The heritability estimates were between 0.14 and 0.47. Estimates of genetic correlation among female traits (PRODAM and STAY) and growth traits ranged from-0.02 to 0.30. Estimates of genetic correlations ranged from 0.23 to 0.94 among growth traits indicating that selection for these traits could be successful in tropical breeding programs. Genetic correlations among all traits were favorable and simultaneous selection for growth, productivity, and stayability is therefore possible. Genetic correlation between PRODAM and STAY was 0.99 and 0.85 for Nelore and composite cattle, respectively. Therefore, PRODAM and STAY might be influenced by many of the same genes. The inclusion of PRODAM instead of STAY as a selection criterion seems to be more advantageous for tropical breeding programs because the generation interval required to obtain accurate estimates of genetic merit for PRODAM is shorter. Average annual genetic changes were greater in Nelore than in composite cattle. This was not unexpected because the breeding program of composite cattle included a large number of farms, different production environments, and genetic level of the herds and breeds. Thus, the selection process has become more difficult in this population. © 2013 American Society of Animal Science. All rights reserved.
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The aim of this study was to evaluate the effects of local, regional and temporal factors structuring fish assemblages in Meridional Amazonian streams during the months of May (rainy season) and August (dry season) of 2008. To accomplish this task, 14 streams located in Serra do Expedito (Aripuanã River basin) were sampled along 30-m stretches. A total of 3,212 specimens distributed among five orders, 18 families, and 55 species were recorded. The fish assemblage structure in the streams presented variation among types of riparian vegetation (local factor) and watersheds (regional factor), but did not present variation between seasons (temporal factor) and stream order (regional factor). Larger streams with margins covered with pasture presented higher species richness and abundance than smaller streams with margins covered with forest. © 2012 Springer Science+Business Media B.V.
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Este estudo investigou a importância dos fatores ambientais sobre os padrões de abundância dos decápodos na costa sudeste brasileira. Amostragens foram feitas mensalmente de janeiro/1998 a dezembro/1999 em Ubatumirim e Mar Virado, região de Ubatuba, usando um barco de pesca camaroneiro equipado com redes doublerig. Foram selecionadas seis áreas adjacentes aos costões rochosos. Amostras de água de fundo foram coletadas usando garrafa de Nansen, para mensurar a temperatura e salinidade. Amostras de sedimento foram obtidas utilizando pegador de Van Veen, para determinação da textura e conteúdo de matéria orgânica. A associação dos fatores ambientais com a abundância das espécies foi verificada através da Análise de Correspondência Canônica (α = 0,05). Quarenta e uma espécies de Decapoda foram utilizadas na análise multivariada. A análise indicou que a textura do sedimento (phi) e a temperatura foram os fatores mais fortemente correlacionados (p < 0,05) com a abundância espacial e temporal das espécies. Considerando a região de estudo como zona de transição faunística, incluindo espécies de origem tropical e subantártica, as espécies responderam diferentemente aos fatores ambientais, principalmente à temperatura. Possivelmente os decápodos ajustem sua distribuição de acordo com suas limitações fisiológicas intrínsecas, como resultado dos recursos disponíveis.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Patterns of spatio-temporal distribution of Brachyura are determined by the interaction among life history traits, inter and intraspecific relationships, as well as by the variation of abiotic factors. This study aimed to characterize patterns of spatio-temporal distribution of Persephona lichtensteinii, Persephona mediterranea and Persephona punctata in two regions of the northern coast of Sao Paulo State, southeastern region of Brazil. Collections were done monthly from July 2001 to June 2003 in Caraguatatuba and Ubatuba, using a shrimp fishery boat equipped with double-rig nets. The patterns of species distribution were tested by means of redundancy analysis (RDA) and generalized linear mixed models (GLMM) in relation to the recorded environmental factors (BT: bottom temperature, BS: bottom salinity, OM: organic matter and granulometry (Phi)). The most influent environmental factor over the species distribution was the Phi, and the ascendant order of influence was P. lichtensteinii, P. punctata and P. mediterranea. The greater abundance of P. mediterranea showed a conservative pattern of distribution for the genus in the sampled region. The greater occurrence of P. punctata and P. lichtensteinii, in distinct transects than those occupied by P. mediterranea, seems to be a strategy to avoid competition among congeneric species, which is related to the substratum specificity.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)