4,315 research outputs found

    Uso da ferramenta Pentaho BI-Server para obtenção de informações gerenciais do Sistema Aberto e Integrado de Informação em Agricultura (Sabiia).

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    Nesse contexto de ambiente de informação, acesso e extração de informações gerenciais da base de dados do sistema Sabiia, o projeto definiu como objetivo estratégico o uso de soluções livres de BI para obtenção de informações e respostas gerenciais, tais como: Quantos provedores de dados estão sendo coletados ? Quais são os provedores de dados coletados em cada país ? Qual é a quantidade de consultas efetuadas por ano, mês e país no sistema ? Quais são as buscas mais efetuadas no sistema ? Devido à maior experiência da Embrapa Informática Agropecuária no uso de soluções livres e arquitetura Java Enterprise Edition (Java EE)4 em projetos de pesquisa, o projeto Sabiia optou pelo uso da ferramenta Pentaho-BI Server5 como solução de (BI) para obtenção de informações gerenciais

    Uso de software livre para implementação de provedores de serviços OAI-PMH: caso do provedor de serviços Sabiia.

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    (LEITE et al., 2009) destacam que a Empresa Brasileira de Pesquisa Agropecuária (Embrapa), por meio do Sistema Embrapa de Bibliotecas (SEB), definiu como objetivo estratégico a inserção da empresa no movimento Acesso Aberto (Open Access Initiative) para armazenamento e disseminação da informação técnico-científica produzida pela área de Pesquisa e Desenvolvimento (P&D) e a criação do provedor de serviços Sistema Aberto e Integrado de Informação em Agricultura (Sabiia), caracterizado como sistema responsável pela integração de todos os dados provenientes de repositórios institucionais, periódicos científicos, bibliotecas digitais e outros, tanto internos quanto externos, de interesse da Embrapa. O presente trabalho focará as soluções livres escolhidas para a construção da ferramenta

    Position dependent photodetector from large area reduced graphene oxide thin films

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    We fabricated large area infrared photodetector devices from thin film of chemically reduced graphene oxide (RGO) sheets and studied their photoresponse as a function of laser position. We found that the photocurrent either increases, decreases or remain almost zero depending upon the position of the laser spot with respect to the electrodes. The position sensitive photoresponse is explained by Schottky barrier modulation at the RGO film-electrode interface. The time response of the photocurrent is dramatically slower than single sheet of graphene possibly due to disorder from the chemically synthesis and interconnecting sheets

    Resonant recoil in extreme mass ratio binary black hole mergers

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    The inspiral and merger of a binary black hole system generally leads to an asymmetric distribution of emitted radiation, and hence a recoil of the remnant black hole directed opposite to the net linear momentum radiated. The recoil velocity is generally largest for comparable mass black holes and particular spin configurations, and approaches zero in the extreme mass ratio limit. It is generally believed that for extreme mass ratios eta<<1, the scaling of the recoil velocity is V {\propto} eta^2, where the proportionality coefficient depends on the spin of the larger hole and the geometry of the system (e.g. orbital inclination). Here we show that for low but nonzero inclination prograde orbits and very rapidly spinning large holes (spin parameter a*>0.9678) the inspiralling binary can pass through resonances where the orbit-averaged radiation-reaction force is nonzero. These resonance crossings lead to a new contribution to the kick, V {\propto} eta^{3/2}. For these configurations and sufficiently extreme mass ratios, this resonant recoil is dominant. While it seems doubtful that the resonant recoil will be astrophysically significant, its existence suggests caution when extrapolating the results of numerical kick results to extreme mass ratios and near-maximal spins.Comment: fixed references; matches PRD accepted version (minor revision); 9 pages, 2 figure

    Molecular Density Functional Theory of Water describing Hydrophobicity at Short and Long Length Scales

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    We present an extension of our recently introduced molecular density functional theory of water [G. Jeanmairet et al., J. Phys. Chem. Lett. 4, 619, 2013] to the solvation of hydrophobic solutes of various sizes, going from angstroms to nanometers. The theory is based on the quadratic expansion of the excess free energy in terms of two classical density fields, the particle density and the multipolar polarization density. Its implementation requires as input a molecular model of water and three measurable bulk properties, namely the structure factor and the k-dependent longitudinal and transverse dielectric susceptibilities. The fine three-dimensional water structure around small hydrophobic molecules is found to be well reproduced. In contrast the computed solvation free-energies appear overestimated and do not exhibit the correct qualitative behavior when the hydrophobic solute is grown in size. These shortcomings are corrected, in the spirit of the Lum-Chandler-Weeks theory, by complementing the functional with a truncated hard-sphere functional acting beyond quadratic order in density. It makes the resulting functional compatible with the Van-der-Waals theory of liquid-vapor coexistence at long range. Compared to available molecular simulations, the approach yields reasonable solvation structure and free energy of hard or soft spheres of increasing size, with a correct qualitative transition from a volume-driven to a surface-driven regime at the nanometer scale.Comment: 24 pages, 8 figure

    The Earth Effect in the MSW Analysis of the Solar Neutrino Experiments

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    We consider the Earth effect in the MSW analysis of the Homestake, Kamiokande, GALLEX, and SAGE solar neutrino experiments. Using the time-averaged data and assuming two-flavor oscillations, the large-angle region of the combined fit extends to much smaller angles (to sin22θ0.1\sin^22\theta \simeq 0.1) than when the Earth effect is ignored. However, the additional constraint from the Kamiokande II day-night data excludes most of the parameter space sensitive to the Earth effect independent of astrophysical uncertainties, and leaves only a small large-angle region close to maximal mixing at 90\% C.L. The nonadiabatic solution remains unaffected by the Earth effect and is still preferred. Both theoretical and experimental uncertainties are included in the analysis.Comment: (11 pages, Revtex 3.0 (can be changed to Latex), 3 postscript figures included, UPR-0570T

    Solar Neutrinos and the Principle of Equivalence

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    We study the proposed solution of the solar neutrino problem which requires a flavor nondiagonal coupling of neutrinos to gravity. We adopt a phenomenological point of view and investigate the consequences of the hypothesis that the neutrino weak interaction eigenstates are linear combinations of the gravitational eigenstates which have slightly different couplings to gravity, f1Gf_1G and f2Gf_2G, f1f2<<1|f_1-f_2| << 1, corresponding to a difference in red-shift between electron and muon neutrinos, Δz/(1+z)f1f2\Delta z/(1+z) \sim |f_1 - f_2|. We perform a χ2\chi^2 analysis of the latest available solar neutrino data and obtain the allowed regions in the space of the relevant parameters. The existing data rule out most of the parameter space which can be probed in solar neutrino experiments, allowing only f1f23×1014|f_1 - f_2| \sim 3 \times 10^{-14} for small values of the mixing angle (2×103sin2(2θG)1022 \times 10^{-3} \le \sin^2(2\theta_G) \le 10^{-2}) and 1016<f1f2<101510^{-16} \stackrel{<}{\sim} |f_1 - f_2| \stackrel{<}{\sim}10^{-15} for large mixing (0.6sin2(2θG)0.90.6 \le \sin^2(2\theta_G) \le 0.9). Measurements of the 8B^8{\rm B}-neutrino energy spectrum in the SNO and Super-Kamiokande experiments will provide stronger constraints independent of all considerations related to solar models. We show that these measurements will be able to exclude part of the allowed region as well as to distinguish between conventional oscillations and oscillations due to the violation of the equivalence principle.Comment: 20 pages + 4 figures, IASSNS-AST 94/5
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