885 resultados para sub-lethal predation


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O presente estudo, enquadrado na área de gestão de recursos humanos, tem como principal objectivo identificar os factores motivacionais que orientam a adesão à especialização, no grupo profissional dos enfermeiros. Trata-se de um estudo de natureza exploratória, transversal, descritivo, analítico, comparativo e quantitativo. A população do estudo foi o grupo de enfermeiros portugueses, sendo a sua amostra composta por 150 enfermeiros. Este grupo foi seleccionado a partir de um processo de amostragem probabilística estratificada, sem reposição. O instrumento de recolha de dados foi o inquérito por questionário. Para o efeito usou-se o questionário da motivação para a formação (QMF) de Carré (2001), tendo sido já adaptado para a população portuguesa por Correia (2009). A formação contínua é uma condição importante no desenvolvimento do indivíduo, quer a nível pessoal, quer a nível profissional; assim como no desempenho da organização onde o indivíduo exerce a sua profissão. O presente trabalho pretende, assim, identificar os factores motivacionais na função de enfermeiro, e que conduzem à adesão da especialização, em particular ao Curso de Pós-Licenciatura em Enfermagem. Numa primeira parte, faz-se a definição e avaliação da função, desenhando-se um mapa de competências; identificando-se, em paralelo, os motivos/expectativas que levam estes profissionais da saúde à especialização desta mesma escala. Decorrente dos resultados obtidos, o presente trabalho conclui que as duas principais motivações dos enfermeiros para a frequência do CPLEE são a motivação extrínseca Operacional Pessoal e a motivação extrínseca Operacional Profissional. Foi ainda possível determinar que a idade, o género, o vínculo à instituição e a situação financeira também têm um papel decisivo no que concerne à motivação dos enfermeiros para a frequência do CPLEE. Este estudo permitiu ainda consolidar o questionário da motivação para a formação desenvolvido por Philippe Carré, aplicado à população portuguesa, de forma a analisar a motivação dos enfermeiros portugueses para a frequência do CPLEE. Quanto às implicações práticas, pretende-se contribuir para o desenvolvimento e melhoria das práticas de recursos humanos no sector da saúde. Balança-se aqui, consequentemente, um equilíbrio entre o diagnóstico organizacional, e a prescrição prática. Potencialmente, poderá servir de roadmap para áreas como o recrutamento e selecção, gestão de carreiras, formação e desenvolvimento, desenho de trabalho e de funções; e, adicionalmente, para uma melhor gestão académica do ensino pós-graduado, na carreira da enfermagem.

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Nos últimos anos estudos efectuados com frutos vermelhos têm revelado a sua riqueza em compostos bioactivos,sobretudo devido a presença de compostos polifenólicos. Neste trabalho foram avaliados os sub-produtos da ginja (Prunus cerasus L.) resultantes da indústria do licor de Óbidos, através da determinação do seu conteúdo em compostos fenólicos totais e, em particular, em antocianinas. As amostras de folhagens (pedúnculos e folhas) e de bagaço (película e película+caroço) foram extraídas por maceração através de 2 métodos de extracção diferentes, utilizando o etanol e o metanol como solventes. Na generalidade observaram-se diferenças significativas entre os teores em fenóis totais e antocianinas, quer dos extractos obtidos a partir de diferentes fracções (folhagem ou bagaço), quer dos extractos obtidos a partir da mesma fracção mas utilizando diferentes solventes. Os extractos das folhagens apresentaram valores de fenóis totais mais elevados que os extractos de bagaço. O metanol foi o solvente mais eficaz na extracção dos fenóis totais e das antocianinas para todas as amostras em estudo. Para as amostras de bagaço as amostras sem caroço (amostras de película) foram as que apresentaram valores mais elevados de fenóis totais e de antocianinas. Os resultados obtidos apontam no sentido dos sub-produtos agro-industriais analisados poderem constituir uma promissora fonte de compostos polifenólicos de custo reduzido, com potencial para aplicação em formulações dermocosméticas. Estudos futuros serão efectuados para avaliar o potencial destes resíduos como ingrediente antioxidante.

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Este artículo convoca a adoptar una posición equilibrada en el análisis de las dimensiones e implicaciones que las crisis individuales de los países andinos tienen para la seguridad subregional. El autor parte de la premisa de que EE.UU. carece de una política clara frente a los problemas de la subregión y sostiene que en este país existe una sensación de pérdida de control, que hace que el tema del narcotráfico se convierta en el único con resonancia política. El autor plantea la necesidad de desarrollar un enfoque multilateral que garantice la seguridad subregional, y coloca a la crisis colombiana como la más grave y preocupante.

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El presente trabajo da cuenta de las representaciones y expresiones que sobre los jóvenes colombianos se construyen y difunden a través de la telerevista La Sub 30, y que tienen como fundamento las intencionalidades de un discurso gubernamental que se gesta desde el Plan Nacional de Cultura y Convivencia del Ministerio de Cultura, a partir del año 2006. En el trabajo se analizan los sentidos que se configuran en el programa y que emergen como representaciones de los jóvenes: lo generacional, lo artístico y lo productivo. Se toma como objeto de estudio ocho emisiones de la telerevista La Sub 30, emitidos a comienzos del primer semestre de 2009. Se opta por una metodología cualitativa de enfoque hermenéutico orientada con aportes teóricos de Stuart Hall, Scott Lash, John Urry, Nikolas Rose y Norman Fairclough. El corpus de análisis está compuesto por fragmentos de discurso verbal de los directores programa, sus presentadores y los jóvenes invitados, los cuales dialogan y se discuten sobre los sentidos que subyacen en ellos. Los resultados se organizan en categorías que permiten evidenciar referentes que caracterizan las representaciones y expresiones de los jóvenes colombianos en la telerevista La Sub 30.

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We tested the hypothesis that cryptically colored eggs would suffer less predation than conspicuous eggs in the ground-nesting red-legged partridge, Alectoris rufa. We used A. rufa as a model species because it has a wide range of natural egg colors, the eggs are widely available from breeding farms, and nests are easily mimicked because they are scrapes containing no vegetation. The study was conducted in the spring of 2001 in forest and fallow fields of central Spain in Castilla La Mancha, Ciudad Real. We used 384 clutches of natural eggs that were white, white spotted, brown, or brown spotted. Within clutches, eggs were consistent in color and size; among clutches, color differences were distributed across habitats. Clutches were checked once after 2 wk of exposure. Cryptic coloration had a survival advantage that was dependent on the local suite of predators. Rodent predation was nonselective with respect to clutch color; however, avian predation was significantly higher for conspicuous clutches. In addition, there was an interaction of landscape and egg color for avian predation. In forest landscapes, the clutches with highest survival were brown spotted, whereas in fallow landscapes, brown and brown spotted clutches had higher survival than white and white potted clutches. Thus, both the predator suite and the landscape had significant effects on the value of cryptic egg coloration. Our study is relevant for conservationists and managers in charge of restocking programs in hunting areas. The release of other partridge species or their hybrids could result in hybridization with wild partridges, potentially leading to nonoptimal clutch pigmentation and reduced survival of the native species. We therefore recommend that local authorities, managers, and conservationists be cautious with the use of alien species and hybrids and release only autochthonous species of partridges within their natural ranges.

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Populations on the periphery of a species' range may experience more severe environmental conditions relative to populations closer to the core of the range. As a consequence, peripheral populations may have lower reproductive success or survival, which may affect their persistence. In this study, we examined the influence of environmental conditions on breeding biology and nest survival in a threatened population of Loggerhead Shrikes (Lanius ludovicianus) at the northern limit of the range in southeastern Alberta, Canada, and compared our estimates with those from shrike populations elsewhere in the range. Over the 2-year study in 1992–1993, clutch sizes averaged 6.4 eggs, and most nests were initiated between mid-May and mid-June. Rate of renesting following initial nest failure was 19%, and there were no known cases of double-brooding. Compared with southern populations, rate of renesting was lower and clutch sizes tended to be larger, whereas the length of the nestling and hatchling periods appeared to be similar. Most nest failures were directly associated with nest predators, but weather had a greater direct effect in 1993. Nest survival models indicated higher daily nest survival during warmer temperatures and lower precipitation, which may include direct effects of weather on nestlings as well as indirect effects on predator behavior or food abundance. Daily nest survival varied over the nesting cycle in a curvilinear pattern, with a slight increase through laying, approximately constant survival through incubation, and a decline through the nestling period. Partial brood loss during the nestling stage was high, particularly in 1993, when conditions were cool and wet. Overall, the lower likelihood of renesting, lower nest survival, and higher partial brood loss appeared to depress reproductive output in this population relative to those elsewhere in the range, and may have increased susceptibility to population declines.

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The effort expended on reproduction may entail future costs, such as reduced survival or fecundity, and these costs can have an important influence on life-history optimization. For birds with precocial offspring, hypothesized costs of reproduction have typically emphasized nutritional and energetic investments in egg formation and incubation. We measured seasonal survival of 3856 radio-marked female Mallards (Anas platyrhynchos) from arrival on the breeding grounds through brood-rearing or cessation of breeding. There was a 2.5-fold direct increase in mortality risk associated with incubating nests in terrestrial habitats, whereas during brood-rearing when breeding females occupy aquatic habitats, mortality risk reached seasonal lows. Mortality risk also varied with calendar date and was highest during periods when large numbers of Mallards were nesting, suggesting that prey-switching behaviors by common predators may exacerbate risks to adults in all breeding stages. Although prior investments in egg laying and incubation affected mortality risk, most relationships were not consistent with the cost of reproduction hypothesis; birds with extensive prior investments in egg production or incubation typically survived better, suggesting that variation in individual quality drove both relationships. We conclude that for breeding female Mallards, the primary cost of reproduction is a fixed cost associated with placing oneself at risk to predators while incubating nests in terrestrial habitats.

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The extent to which species are plastic in the timing of their reproductive events relative to phenology suggests how climate change might affect their demography. An ecological mismatch between the timing of hatch for avian species and the peak availability in quality and quantity of forage for rapidly growing offspring might ultimately affect recruitment to the breeding population unless individuals can adjust the timing of breeding to adapt to changing phenology. We evaluated effects of goose density, hatch timing relative to forage plant phenology, and weather indices on annual growth of pre-fledging Canada geese (Branta canadensis) from 1993-2010 at Akimiski Island, Nunavut. We found effects of both density and hatch timing relative to forage plant phenology; the earlier that eggs hatched relative to forage plant phenology, the larger the mean gosling size near fledging. Goslings were smallest in years when hatch was latest relative to forage plant phenology, and when local abundance of breeding adults was highest. We found no evidence for a trend in relative hatch timing, but it was apparent that in early springs, Canada geese tended to hatch later relative to vegetation phenology, suggesting that geese were not always able to adjust the timing of nesting as rapidly as vegetation phenology was advanced. Analyses using forage biomass information revealed a positive relationship between gosling size and per capita biomass availability, suggesting a causal mechanism for the density effect. The effects of weather parameters explained additional variation in mean annual gosling size, although total June and July rainfall had a small additive effect on gosling size. Modelling of annual first-year survival probability using mean annual gosling size as an annual covariate revealed a positive relationship, suggesting that reduced gosling growth negatively impacts recruitment.

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Estimates for the sedimentation rate of realistic ice crystals at sizes smaller than 100 µm are presented. These calculations, which exploit new results for the capacitance of ice crystals, are compared with laboratory studies and found to be in good agreement. The results highlight a weakness in contemporary ice particle fall speed parametrizations for very small crystals, which can lead to sedimentation rates being overestimated by a factor of two. The theoretical approach applied here may also be useful for calculating the sedimentation rate and mobility of non-spherical aerosol particles.