382 resultados para perturbação


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

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The Atlantic Rainforest biome has been going through fragmentation processes caused by agriculture and urbanization in green areas. Structural studies associated with the silvigenetic approach allow the understanding of what the past has caused in the present structure and predict future conditions of disturbed fragments. The objective of this study was to compare the composition and diversity of arboreous natural regeneration of steady-state and reorganization ecounits in two Seasonal Semideciduous Forest fragments. The hypothesis was that specific composition varies in these two different ecounits due to differential adaptation of species in canopy gaps and closed canopy. The survey was made in three areas with different perturbation backgrounds of 0,5 ha each. 60 permanent plots of 4m² each (2m x 2m) were stablished along the studied fragments following the proportion of ecounits presented in a previous mapping. Each plot was divided in 4 sub-plots of 1m² and arboreous individuals between 0,20m and 1,30m height were sampled and posteriorly separated in two height classes: I) individuals between 0,20m and 0,50m height (2m² sampling) and II) individuals between 0,51m and 1,30m height (4m² sampling). It was sampled 338 individuals from 53 families and 23 species. The Shannon index was 3,26 (Area A), 2,27 (Area B) and 2,42 (Area C) whereas Areas B and C values are considered low in our state Semidecidous Forests. Steady-state ecounits presented the highest values for abundance and species richness. Chi-square test pointed out species’ selection for determined ecounits in the studied community. Rarefaction method analysis showed diversity increase in steady-state ecounits and a stablishment in species richness curves for reorganization ecounits

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Pós-graduação em Matemática em Rede Nacional - IBILCE

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Pós-graduação em Física - FEG

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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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The location of Jundiai-Mirim river basin, close to large urban centers and industrial parks, has contributed to the appreciation of their lands. Consequently, the region has an intense process of urbanization that resulted in an increasing environmental disturbance in the forest areas. Given the need to preserve existing natural vegetation, because the watershed is the source of water used to supply Jundiai, SP, this study evaluated changes in the environmental quality of the watershed forest fragments between 1972 and 2013. The environment quality was determined by evaluating nine indicators of environmental disturbance, obtained by techniques of Geoprocessing and integrated by Multicriteria Analysis. The results showed a constant tendency of deteriorating the environmental quality of natural vegetation between 1972 and 2013, attributed to the intense process of occupation of the watershed. It is concluded that: (a) urbanization and deforestation of natural vegetation were primarily responsible for changes in environmental quality; (b) there is a need to create public policies to preserve the natural vegetation in the watershed.

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Pós-graduação em Física - FEG

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Mining activities are directly related to changes in natural landscapes. With the objective of analyzing the changes imposed by the geomorphological dynamics of human action in areas of mining clay, two fragments were selected from the basin of Ribeirão Santa Gertrudes / SP, representing denudational and sedimentation processes respectively. This area is within the context of the Ceramic Pole Santa Gertrudes / SP, which besides its importance as a supplier of raw material, is characterized as the largest center of international reference in ceramic tiles on the American continent. Data was collected and analyzed from the perspective of anthropogenic geomorphology supported by general systems theory and uses techniques from evolutionary geomorphological mapping. Thus, geomorphological mapping were produced concerning three scenarios, which date from 1962, 1988 and 2006 in a scale of 1:10.000. These surveys allowed us to infer a detailed investigation of the evolution of changes in topography and hydrology, geomorphology representative of the original (1962), which has characteristics of an earlier phase of earlier existing large mining pits, and its evolution to a anthropogenic geomorphological stage, represented by active disruption scenarios dating from 1988 and 2006. The last two scenarios have analyzed changes in the dimensions of relief features when compared with the original scenario representative of geomorphology, as well as an intense reallocation of surface and subsurface materials, in which human action is highlighted by becoming responsible for sculpting the landscape through the imposition of control mechanisms to natural processes.

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The main article aim was to investigate the collecting system of a dissolved air flotation (DAF) unit in pilot scale. Referring to the collecting system position, two options were analyzed: (i) top manifold and (ii) bottom manifold, pipes or plates. Qualitative and quantitative essays were performed, as image and stimulusresponse tests, respectively. The results of the essays standardized were adjusted by N-continuous stirred tank reactors in series and theoretical models of dispersion (low and high). The bottom manifold (plates with orifices) was more appropriate. The results pointed out that the N-continuous stirred tank reactors in series model was more adequate to describe the hydrodynamic behavior of the DAF unit.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The dynamics of the rotation of a satellite is an old and classical problem, specially in the Euler formalism. However, with these variables, even in torque free motion problem, the integrability of the system is far from trivial, mainly when the three moments of the inertia are not equal. Another disadvantage occurs when the inclinations between some plans are null or close to zero, so the nodes become undetermined. In this work, we propose the use of modern Andoyer's variables. These are a set of canonical variables and therefore some significant advantages can be obtained when dealing with perturbation methods. On other the hand, the integrability of the torque free motion becomes very clear, as the system is reduced to a problem of one degree of freedom. The elimination of the singularities mentioned above, can be solved very easily, with Pincaré-type variables. In this work we give the background concepts of the Andoyer's variables and the disturbing potential is obtained for the rotational dynamics of a satellite perturbed by a planet. In the case when A = B (moments of inertia) and due to the current variables, the averaged system is trivially obtained through very simple integrations