13,116 research outputs found

    Effects of personal, social and environmental factors on physical activity behavior among adults

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    Despite the guidelines and the well-recognized benefits of regular physical activity, there is evidence that a large number of people is still reported to be inactive. Therefore, the need for interventions that can promote a healthier behavior has increased. As an understanding of the determinants of physical activity behavior by health professionals is an important prerequisite to designing effective interventions, studies on the identification of the determinants of physical activity are warranted. The purpose of this work is to review and update the research on determinants underlying physical activity behaviour in adults and to provide an overview of physical activity patterns among adult populations. The findings highlight the need for an evaluation of the interactive effects of psychosocial, cultural, environmental and public policy influences on physical activity forging a trans-disciplinary paradigm

    Physics of Psychophysics: Stevens and Weber-Fechner laws are transfer functions of excitable media

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    Sensory arrays made of coupled excitable elements can improve both their input sensitivity and dynamic range due to collective non-linear wave properties. This mechanism is studied in a neural network of electrically coupled (e.g. via gap junctions) elements subject to a Poisson signal process. The network response interpolates between a Weber-Fechner logarithmic law and a Stevens power law depending on the relative refractory period of the cell. Therefore, these non-linear transformations of the input level could be performed in the sensory periphery simply due to a basic property: the transfer function of excitable media.Comment: 4 pages, 5 figure

    Rooting Pattern Distribution and Spatial Variability of Italian Ryegrass (Lolium Multiflorum Lam) in a Mediterranean Region

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    It is estimated that less than 10% of the studies on pastures and forages have evaluated the subterranean biomass production. The objective of this study was to evaluate for a Mediterranean region the rooting characteristics and spatial variability of Italian ryegrass (Lolium multiflorum Lam) under two different soil water status conditions

    (De)Localization in the Prime Schrodinger Operator

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    It is reported a combined numerical approach to study the localization properties of the one-dimensional tight-binding model with potential modulated along the prime numbers. A localization-delocalization transition was found as function of the potential intensity; it is also argued that there are delocalized states for any value of the potential intensity.Comment: 7 pages, 4 figures; to be published in J. Phys. A: Math. Ge

    Concorrência promovida pelo taperebazeiro sobre o cupuaçuzeiro, em sistema agroflorestal.

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    O Sistema Agroflorestal (SAF) é um modelo em expansão, principalmente quando voltado para a agricultura familiar, no sentido de fortalecer os novos moldes da agroecologia. O cupuaçuzeiro é uma das espécies amazônicas que toleram o sombreamento e pode ser facilmente consorciado com outras espécies. O taperebazeiro (ou cajazeira) é uma espécie que está em fase final de domesticação. Este trabalho teve por objetivo avaliar se plantas de taperebazeiro, quando em consórcio com cupuaçuzeiro, causavam algum tipo de depressão, seja no desenvolvimento vegetativo, ou na produção de frutos do cupuaçuzeiro. O arranjo campo foi composto pelo cupuaçuzeiro no espaçamento de 5 x 5 m e. 20 x 20 m para o taperebazeiro, instalado em um plantio comercial no Nordeste paraense. Observou-se que não houve prejuízo para o cupuaçuzeiro, nos primeiros anos de cultivo, tanto para o desenvolvimento vegetativo quanto produção de frutos. Entretanto com o desenvolvimento do sistema foi possível observar leve depressão na produção de frutos do cupuaçuzeiro, porém, esses prejuízos ficaram aquém dos benefícios globais do Sistema Agroflorestal

    Concorrência entre mogno africano e cupuaçuzeiro em sistema agroflorestal na Amazônia.

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    Esta pesquisa teve por objetivo verificar e quantificar o possível efeito da concorrência do mogno africano (Khaya ivorensis A. Chev), sobre plantas de cupuaçuzeiro (Theobroma grandiflorum Wild ex. Schum.), em um sistema agroflorestal
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