27 resultados para Individual level

em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"


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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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How individual-level movement decisions in response to habitat edges influence population-level patterns of persistence and spread of a species is a major challenge in spatial ecology and conservation biology. Here, we integrate novel insights into edge behavior, based on habitat preference and movement rates, into spatially explicit growth-dispersal models. We demonstrate how crucial ecological quantities (e.g., minimal patch size, spread rate) depend critically on these individual-level decisions. In particular, we find that including edge behavior properly in these models gives qualitatively different and intuitively more reasonable results than those of some previous studies that did not consider this level of detail. Our results highlight the importance of new empirical work on individual movement response to habitat edges. © 2013 by The University of Chicago.

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A total of 459 (245 females, 214 males) Atlantoraja cyclophora was captured by bottom trawl off the coast of Rio Grande do Sul between 30 degrees 40'S and 34 degrees 30'S during surveys conducted in winter 2001 and summer/autumn 2002 at depths of 100-300 M. Total length at maturity was 52.8 cm for females and 48.5 cm for males. Symmetry and functional parity of the gonads were observed in both sexes, but there was no significant temporal variation in either sex for any of the reproductive parameters studied. Ovulation and egg-deposition were similarly intensive in both seasons. In adult females, there was an ovarian resting period at an individual level, though it was not synchronized at a population level. Distribution of egg-bearing females was not related to depth or species' range. (c) 2005 International Council for the Exploration of the Sea, Published by Elsevier Ltd. All rights reserved.

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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)

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The present paper reports nuclear DNA content in 30 Neotropical freshwater fish species and summarizes the data on other Neotropical species presented in the literature. Among Neotropical fishes, the nuclear DNA content ranges from 1.04 ± 0.09 pg/nucleus in Corydoras cf. simulatus (2n = 62) to 248.0 pg/nucleus in Lepidosiren paradoxa (2n = 38). A general analysis of the data obtained in the present study for each species showed that DNA measurements were practically constant at the individual level, while significant differences were observed among individuals of the same population. This observation was valid for all species analyzed and was more evident in those species that presented other karyotypic particularities such as sex chromosomes or supernumerary chromosomes. The importance of changes in nuclear DNA content in the evolutionary process of Neotropical fishes is discussed.

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The objective of this work was to study the effect of selective thinning on the estimates of genetic parameters in progenies of Pinus caribaea var. hondurensis. The progeny test was installed in June 1986, following a 10 × 10, triple square lattice design, containing ten trees in linear plots in 3.0 × 3.0m spacing. Twelve years after the planting, a selective thinning based on Multi-effect index (selection for DBH) was performed, leaving six trees per plot. The assessments were done in four situations: A (before thinning); B (among thinned trees); C (among remnant trees at 13 years of age) and D (two years after the thinning). The following traits were analyzed: total height (H), diameter at breast height (DBH), volume (VOL), stem form (FOR), foxtail (FT), wood density at 1.3 m (WD1) and wood density at the half height (WD2). The thinning led to increase in the estimates of variability among progenies for VOL and decrease for ALT and DBH. There was a high and positive genetic correlation among the growth traits, mainly between DBH and VOL. The latter remained unchanged after thinning. The narrow-sense heritabilities at the individual level, showed a slight increase while at the family mean level had a reduction with the thinning. The estimates of breeding values increased with the thinning. This may lead to an easier identification of the best progenies in further selection.

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This study describes the male reproductive cycle of Sibynomorphus mikanii from southeastern Brazil considering macroscopic and microscopic variables. Spermatogenesis occurs during spring-summer (September-December) and spermiogenesis or maturation occurs in summer (December-February). The length and width of the kidney, the tubular diameter, and the epithelium height of the sexual segment of the kidney (SSK) are larger in summer-autumn (December-May). Histochemical reaction of the SSK [periodic acid-Schiff (PAS) and bromophenol blue (BB)] shows stronger results during summer-autumn, indicating an increase in the secretory activity of the granules. Testicular regression is observed in autumn and early winter (March-June) when a peak in the width of the ductus deferens occurs. The distal ductus deferens as well as the ampulla ductus deferentis exhibit secretory activities with positive reaction for PAS and BB. These results suggest that this secretion may nourish the spermatozoa while they are being stored in the ductus deferens. The increase in the Leydig cell nuclear diameter in association with SSK hypertrophy and the presence of sperm in the female indicate that the mating season occurs in autumn when testes begin to decrease their activity. The peak activity of Leydig cells and SSK exhibits an associated pattern with the mating season. However, spermatogenesis is dissociated of the copulation characterizing a complex reproductive cycle. At the individual level, S. mikanii males present a continuous cyclical reproductive pattern in the testes and kidneys (SSK), whereas at the populational level the reproductive pattern may be classified as seasonal semisynchronous. © 2012 Wiley Periodicals, Inc.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Ciências Biológicas (Zoologia) - IBRC

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Pós-graduação em Ciências Cartográficas - FCT

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Pós-graduação em Agronomia (Genética e Melhoramento de Plantas) - FCAV

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)