4 resultados para Amazon economic structure


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The complex three-dimensional (3-D) structure of tropical forests generates a diversity of light environments for canopy and understory trees. Understanding diurnal and seasonal changes in light availability is critical for interpreting measurements of net ecosystem exchange and improving ecosystem models. Here, we used the Discrete Anisotropic Radiative Transfer (DART) model to simulate leaf absorption of photosynthetically active radiation (lAPAR) for an Amazon forest. The 3-D model scene was developed from airborne lidar data, and local measurements of leaf reflectance, aerosols, and PAR were used to model lAPAR under direct and diffuse illumination conditions. Simulated lAPAR under clear-sky and cloudy conditions was corrected for light saturation effects to estimate light utilization, the fraction of lAPAR available for photosynthesis. Although the fraction of incoming PAR absorbed by leaves was consistent throughout the year (0.80?0.82), light utilization varied seasonally (0.67?0.74), with minimum values during the Amazon dry season. Shadowing and light saturation effects moderated potential gains in forest productivity from increasing PAR during dry-season months when the diffuse fraction from clouds and aerosols was low. Comparisons between DART and other models highlighted the role of 3-D forest structure to account for seasonal changes in light utilization. Our findings highlight how directional illumination and forest 3-D structure combine to influence diurnal and seasonal variability in light utilization, independent of further changes in leaf area, leaf age, or environmental controls on canopy photosynthesis. Changing illumination geometry constitutes an alternative biophysical explanation for observed seasonality in Amazon forest productivity without changes in canopy phenology.

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This paper presents the results of a research on the way which shows the role of the farmer women to contribute to overcome the life hindrances in the Amazonian agroforest environment, for food safety and familiar income. The sample was the women of the Associação de Produtores Alternativos - APA, Ouro Preto do Oeste, Rondônia, Brazil. Questionnaires were applied to 50 women of this community, in 2004/2005, with additional interviews in 2006, taking into account their role in the farms, and their several invisible activities. The role of APA?s women was compared to that of other Amazonian women, like rubber tappers and riverine people. The APA?s women perform tasks as field manpower - 78.0% of them, making decisions about what to plant - 18.0%, harvest destination - 32.0%, which animals to raise -14.0% and animal products destination -34.0%. Traditionally, in rural zone, the women with their children play a role as non-paid manpower, getting some monetary income with occasional commercialization of on-farm processed products as cheese, pickles, jellies and fruit liqueurs. They are responsible for the cultures practiced around the house. All these Amazonian women edaphoclimatic conditions, greatly contributing to the biodiversity, conservation, and to ecological, social and economic stability.are guardians, perpetuators and disseminators of a rich germplasm adapted to local.

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Aeromonas hydrophila is causing substantial economic losses in world aquaculture. This study determined the tolerance limit (LD50-96h) of A. hydrophila in Arapaima gigas, and also investigated the clinical signs after intradermal inoculation.

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The paper describes a forest management system to be applied on smallholder farms, particularly on settlement projects in the Brazilian Amazon. The proposed forest management system was designed to generate a new source of family income and to maintain forest structure and biodiversity. The system is new in three main characteristics: the use of short cycles in the management of tropical forests, the low harvesting intensity and environmental impact, and the direct involvement of the local population in ali forest management activities. It is based on a minimum felling cycle of ten years and an annual timber harvest of 5-10 m3 ha-1.