20,874 research outputs found

    Segurança operacional de exploração florestal mecanizada.

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    Construção de estradas florestais e transporte florestal rodoviário na região amazônica.

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    bitstream/item/33677/1/CPATU-CirTec6.pd

    Transparency in International Anti-Corruption Helpdesk Answers: A Case Study in Timor-Leste

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    This study provides an overview of corruption in Timor-Leste. The extent of corruption in the government and public service. This paper asks: who are the stakeholders? How can they work together? How do these actors manage or fail to manage corruption? More broadly, which successful collaboration mechanisms can be identified from the literature about how to reduce corruption? To provide an answer, in this paper, the literature on an overview of Timor-Leste (TL) corruption is extensively reviewed, with a focus on five particular sectors: an overview of corruption in Timor Leste, primary drivers of corruption, corruption in crucial sectors, legal and institutional framework, other stakeholders, lesson learned from Developed Countries. The paper gives solutions include the nine broad areas of corruption risk mapping, subsidy registers and sunset clauses, transparency initiatives, anti-corruption laws, shared-ownership models between fragile developing countries, partnership with developed countries as continues learning and improvement, national and local culture sensibilities, international connectivity of public corruption perception index, and invested in human capital development

    Exploração mecanizada da floresta tropical úmida sem babaçu.

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    Rendimento de derruba e extração mecanizada em florestas de terra firme da Amazônia.

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    Hierarchical Spatial Organization of Geographical Networks

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    In this work we propose the use of a hirarchical extension of the polygonality index as a means to characterize and model geographical networks: each node is associated with the spatial position of the nodes, while the edges of the network are defined by progressive connectivity adjacencies. Through the analysis of such networks, while relating its topological and geometrical properties, it is possible to obtain important indications about the development dynamics of the networks under analysis. The potential of the methodology is illustrated with respect to synthetic geographical networks.Comment: 3 page, 3 figures. A wokring manuscript: suggestions welcome

    Efeito da radiação ultravioleta-B sobre a germinação de conídios de Botrytis cinerea e colonização em discos de morango.

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    RESUMO: O ultravioleta é um fator de grande impacto na agricultura e está intimamente relacionado à camada de ozônio, a qual vem sendo reduzida paulatinamente, em consequência das atividades antrópicas. A camada de ozônio está sendo degradada, principalmente, por ação dos clorofluorcarbonos (CFC) utilizados pelo homem alterando assim a intensidade de radiação ultravioleta na superfície terrestre em especial no comprimento de onda da radiação ultravioleta B (UV-B). O objetivo do trabalho foi avaliar a resistência de conídios de Botrytis cinerea à radiação UV-B. Foram testados 13 isolados do patógeno, onde uma suspensão contendo 105 conídios mL-1 de cada isolado foi preparada e uma alíquota de 20 ?L foi colocada no centro de uma placa de Petri contendo BDA. Os conídios foram expostos à radiação UV-B 5,6 kJ m-2 a uma irradiância de 823 mW m-2. Também foi avaliada a esporulação de B. cinerea em discos de folha de morangueiro em meio de cultura paraquat-clorofenicolágar (PCA). Os isolados apresentaram germinação relativa entre 15% e 90%, sendo que os isolados com maior resistência à radiação UV-B foram o LQC 162, LQC 150 e LQC 159. No teste da esporulação foi observado maior diferenças entre os isolados quanto a formação de conidióforos do patógeno sendo os isolados LQC 150 e LQC 157 superiores aos outros isolados. Foi selecionado o isolado LQC 150 para ensaios posteriores onde será comparada a tolerância desse isolado com isolados de agentes de controle biológico deste patógeno quanto a tolerância a radiação UV-B

    Geometric Phase, Curvature, and Extrapotentials in Constrained Quantum Systems

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    We derive an effective Hamiltonian for a quantum system constrained to a submanifold (the constraint manifold) of configuration space (the ambient space) by an infinite restoring force. We pay special attention to how this Hamiltonian depends on quantities which are external to the constraint manifold, such as the external curvature of the constraint manifold, the (Riemannian) curvature of the ambient space, and the constraining potential. In particular, we find the remarkable fact that the twisting of the constraining potential appears as a gauge potential in the constrained Hamiltonian. This gauge potential is an example of geometric phase, closely related to that originally discussed by Berry. The constrained Hamiltonian also contains an effective potential depending on the external curvature of the constraint manifold, the curvature of the ambient space, and the twisting of the constraining potential. The general nature of our analysis allows applications to a wide variety of problems, such as rigid molecules, the evolution of molecular systems along reaction paths, and quantum strip waveguides.Comment: 27 pages with 1 figure, submitted to Phys. Rev.

    Far Infrared Slab Lensing and Subwavelength Imaging in Crystal Quartz

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    We examine the possibility of using negative refraction stemming from the phonon response in an anisotropic crystal to create a simple slab lens with plane parallel sides, and show that imaging from such a lens should be possible at room temperature despite the effects of absorption that are inevitably present due to phonon damping. In particular, we consider the case of crystal quartz, a system for which experimental measurements consistent with all-angle negative refraction have already been demonstrated. Furthermore, we investigate the possibility of subwavelength imaging from such materials, and show that it should be possible for certain configurations.Comment: 12 pages, 10 figure
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