Mapeamento de áreas de preservação permanentes em topos de morros para a Amazônia Legal usando metodologia apropriada a grande volume de dados.

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Análise da savana e queimadas no Parque Indígena de Tumucumaque (PA) através de imagens de satélite Landsat.

The Tiriyós Savanna, inserted in the Indian Park of Tumucumaque (PA), and the occurrence of fires were analyzed using satellite images. The savanna common and permanent area in the years of 1986 and 2005 was 4.109,72 km2. The total retraction and expansion areas in the same years were 287,3 km2 and 151,8 km2, respectively. From the burnt area, 38,5% presented only one focus of fire in 9 years (from 1998 August to 2006 October); in 23,6% of the area there was fire each 4 and a half years; 25,3% each 31 months; 10,8% each 18 months and 1,8% each year. The total estimated burnt area was 4.086 km2, at maximum. The fires are considered one of the pressure factors for the advance of the amazon savannas and in the change of the coverage and usage of the earth in the Tiriyós savanna area, but the analysis of the satellite images in the years of 1986 and 2005 showed that there was a retraction of 135,5 km2 in 20 years

Simulation of Bulk Silicon Crystals and Si(111) Surfaces with Application to a Study of Fluorine Coverage of the Surfaces

Computational efficiency for the simulation of bulk crystals and surfaces is highly desirable. In an effort to study semiconductor crystals, we present a self-consistent treatment for the simulation of silicon crystals and surfaces based on the combination of a siligen model and a semiempirical Hamiltonian method. An artificial atom called siligen is introduced for the application of the semiempirical method to finite-size silicon clusters. The calculated average bond energies for the saturated silicon clusters are between 2.045 and 2.568 eV, compared to the measured value of 2.31 eV. A simulated bulk silicon surface using siligens is introduced in order to examine variation of the bond strength between fluorine atoms and the simulated silicon (111) surface. It is found that bond strength computed from the simulated surface, with siligens, rapidly converges to a saturated limit as the number of surface layers increases, while a pure silicon (111) surface without siligens yields no satisfactory convergence

A dinâmica florestal no pólo agropecuário do nordeste paulista

No contexto do histórico de uso e ocupação das terras do Estado de São Paulo, que resultou na perda quase total de suas florestas originais e degradação dos remanescentes, as atividades agropecuárias são identificadas como potenciais condicionantes pela crescente expansão ocorrida nas últimas décadas. Por outro lado, levantamentos atuais, como o realizado pelo Instituto Florestal de São Paulo, demonstram um incremento na área mapeada como vegetação nativa do Estado (ZORZETTO, 2010), com curva ascendente similar às formulações recentes da Teoria da Transição Florestal (RUDEL, 1998; RUDEL et al., 2005). De acordo com essa Teoria, os estoques florestais mudam de modo previsível, com o decréscimo da taxa de desflorestamento e aumento da taxa de regeneração ocorrendo ao longo do tempo, associadas a mudanças na sociedade civil e regulações governamentais que facilitariam essa transição. No Brasil, o Código Florestal de 1965 representou um importante instrumento disciplinador das atividades florestais (BORGES et al., 2009), bem como a Lei n° 6.938 de 1981, que dispôs sobre a Política Nacional do Meio Ambiente (PNMA), mas apenas com a promulgação da atual Constituição Brasileira, em 1988, o Direito Ambiental se consolidou. As especificações das Áreas de Preservação Permanente e de Reserva Legal foram dadas posteriormente pela Lei nº 7.803 de 1989 e Medida Provisória nº 2.166-67 de 2001, respectivamente. Considerando as recentes demandas por certificações ambientais que incentivam o cumprimento da legislação ambiental, as adequações de propriedades voltadas às atividades agropecuárias poderiam refletir na dinâmica do uso e ocupação das terras e, consequentemente, na ampliação de áreas de vegetação, bem como nos indicadores socioeconômicos regionais. O entendimento da relação espacial entre essas variáveis ? ambientais, sociais e econômicas ? torna-se, portanto, essencial para embasar políticas públicas facilitadoras desse processo de regeneração florestal. No nordeste do Estado de São Paulo, importante pólo do agronegócio, houve intensas alterações de uso da terra associadas às atividades agropecuárias no período entre os anos de 1988 e 2003, em que a área plantada de cana-de-açúcar praticamente dobrou ao mesmo tempo em que houve o declínio de áreas de pastagem (QUARTAROLI et al., 2006). Nesse ambiente diversificado, com áreas também de fruticultura, culturas anuais e manchas urbanas, foi identificado um incremento de vegetação no período, distribuído pelos municípios inclusos nessa região.bitstream/item/56789/1/016-11.pd

Perturbations and Critical Behavior in the Self-Similar Gravitational Collapse of a Massless Scalar Field

This paper studies the perturbations of the continuously self-similar critical solution of the gravitational collapse of a massless scalar field (Roberts solution). The perturbation equations are derived and solved exactly. The perturbation spectrum is found to be not discrete, but occupying continuous region of the complex plane. The renormalization group calculation gives the value of the mass-scaling exponent equal to 1.Comment: 12 pages, RevTeX 3.1, 1 figur

Self-Similar Collapse of Scalar Field in Higher Dimensions

This paper constructs continuously self-similar solution of a spherically symmetric gravitational collapse of a scalar field in n dimensions. The qualitative behavior of these solutions is explained, and closed-form answers are provided where possible. Equivalence of scalar field couplings is used to show a way to generalize minimally coupled scalar field solutions to the model with general coupling.Comment: RevTex 3.1, 15 pages, 3 figures; references adde

Scaling impacted structures

Summary The problem of non-scalability of structures under impact loads caused by strainrate effects is solved in this article by properly correcting the impact velocity. The technique relies on the use of an alternative dimensionless basis, together with a mathematical model which allows the calculation of a correction factor for the impact velocity. This new velocity, when applied to the model, makes it to assure the satisfaction of the scaling laws. The indirect similitude method detailed here is applied to two strain-rate sensitive structures, a double plate under in-plane impact and a beam subjected to a blast load. The results show a very good agreement so that the model and a prototype made from strain rate sensitive materials behave the same

Sistema de gestão territorial da faixa de fronteira para a defesa agropecuária.

This article presents a technical note about the initiatives developed by Embrapa Satellite Monitoring and the Office of the Secretary of Agricultural Defense - SDA of the Agriculture, Livestock farming and Supplying - MAPA. Those actions are going to structure a system of territorial management of Brazilian borderlands aimaing to support efforts toward the prevention, monitoring and control of the incidence of sanitary risks

Global tropical forest cover change assessment with medium spatial stellite imagery using a systematic sample grid - data, methods and first results.

At the Joint Research Centre (JRC) of the European Commission, a methodology has been developed to monitor the pan-tropical forest cover with remote sensing data for the years 1990-2000-2005 in Latin America, Southeast Asia and Africa on the basis of over 4000 sample units sample units with a dimension of 20 km by 20 km located at every full latitude and longitude degree confluence. From the Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper (ETM) instruments, images with low cloud impact from the epochs around the years 1990, 2000 and 2005 were selected and subsets covering the sample units were cut-out, pre-processed, segmented and classified in five different land cover classes in order to build global and regional statistics on tropical forest cover change. The data was validated in three steps, internal correction of wrongly classified objects, external (national or regional) expert validation and internal harmonization of the data. In this paper, the data collection and the workflow of the forest cover change assessment for the epochs 1990 and 2000 is presented. Parts of the results for the Brazilian Amazon have been validated by comparing with interpretations of corresponding samples carried out by the Instituto Nacional de Pesquisas Espaciais (INPE), showing a very high correlation. Further, the figure produced by INPE through the PRODES program on gross deforestation for the years 1990-2000 was compared to the figure calculated on basis of the JRC results for the respective area, where the JRC estimate that was ca. 10% higher than the INPE estimate

Self-Similar Collapse of Conformally Coupled Scalar Fields

A massless scalar field minimally coupled to the gravitational field in a simplified spherical symmetry is discussed. It is shown that, in this case, the solution found by Roberts, describing a scalar field collapse, is in fact the most general one. Taking that solution as departure point, a study of the gravitational collapse for the self-similar conformal case is presented.Comment: 9 pages, accepted for publication, Classical and Quantum Gravity. Available at http://dft.if.uerj.br/preprint/e-17.tex or at ftp://dft.if.uerj.br/preprint/e-17.tex . Figures can be obtained on request at [email protected]