9,034 research outputs found

    Processo de Seleção Escape para Obtenção de Plantas de Pessegueiro e Ameixeira com Alta Sanidade.

    Get PDF
    bitstream/item/30951/1/Circular-84.pd

    Dynamics of a Generalized Cosmological Scalar-Tensor Theory

    Get PDF
    A generalized scalar-tensor theory is investigated whose cosmological term depends on both a scalar field and its time derivative. A correspondence with solutions of five-dimensional Space-Time-Matter theory is noted. Analytic solutions are found for the scale factor, scalar field and cosmological term. Models with free parameters of order unity are consistent with recent observational data and could be relevant to both the dark-matter and cosmological-"constant" problems.Comment: 13 page

    Radiolysis of ammonia-containing ices by energetic, heavy and highly charged ions inside dense astrophysical environments

    Full text link
    Deeply inside dense molecular clouds and protostellar disks, the interstellar ices are protected from stellar energetic UV photons. However, X-rays and energetic cosmic rays can penetrate inside these regions triggering chemical reactions, molecular dissociation and evaporation processes. We present experimental studies on the interaction of heavy, highly charged and energetic ions (46 MeV Ni^13+) with ammonia-containing ices in an attempt to simulate the physical chemistry induced by heavy ion cosmic rays inside dense astrophysical environments. The measurements were performed inside a high vacuum chamber coupled to the heavy ion accelerator GANIL (Grand Accelerateur National d'Ions Lourds) in Caen, France.\textit{In-situ} analysis is performed by a Fourier transform infrared spectrometer (FTIR) at different fluences. The averaged values for the dissociation cross section of water, ammonia and carbon monoxide due to heavy cosmic ray ion analogs are ~2x10^{-13}, 1.4x10^{-13} and 1.9x10^{-13} cm2^2, respectively. In the presence of a typical heavy cosmic ray field, the estimated half life for the studied species is 2-3x10^6 years. The ice compaction (micropore collapse) due to heavy cosmic rays seems to be at least 3 orders of magnitude higher than the one promoted by (0.8 MeV) protons . In the case of the irradiated H2O:NH3:CO ice, the infrared spectrum at room temperature reveals five bands that were tentatively assigned to vibration modes of the zwitterionic glycine (+NH3CH2COO-).Comment: Accepted to be published in Astronomy and Astrophysics; Number of pages: 12; Number of Figures: 7; Number of Tables:

    Anisotropic elastic theory of preloaded granular media

    Full text link
    A macroscopic elastic description of stresses in static, preloaded granular media is derived systematically from the microscopic elasticity of individual inter-grain contacts. The assumed preloaded state and friction at contacts ensure that the network of inter-grain contacts is not altered by small perturbations. The texture of this network, set by the preparation of the system, is encoded in second and fourth order fabric tensors. A small perturbation generates both normal and tangential inter-grain forces, the latter causing grains to reorient. This reorientation response and the incremental stress are expressed in terms of the macroscopic strain.Comment: 7 pages, 2 figures. Accepted version. [email protected] [email protected]

    A gestão do conhecimento como ferrammenta para potencializar o desenvolvimento de equipes na geração e execução de projetos de P&D.

    Get PDF
    Breve apreciação da gestão do conhecimento na Embrapa; Um modelo de maturidade da gestão do conhecimento como ferramenta de análise de uma instituição; Suporte e referencial teórico para implantação de um programa de GC; Ambiente de conhecimento; Inteligência competitiva; Redes de relacionamento; Apoio à pesquisa; Uma perspectiva de gestão do conhecimento para unidades de pesquisa; Aspectos gerais de um programa para unidades de pesquisa; Aspectos gerais de um programa para gestão do conhecimento aplicada a projetos de PD&I; Ações e efeitosda gestão do conhecimento no âmbito de um projeto de P&D.bitstream/item/58221/1/doc118.pd

    Fosfatos Naturais na Adubação de Sistema de Culturas de Verão com Ênfase no Arroz Irrigado.

    Get PDF
    bitstream/item/30829/1/Circular-66.pd

    Experiência a campo com inseminação artificial de suínos.

    Get PDF
    bitstream/item/59338/1/CUsersPiazzonDocuments16.pd

    Uso de modelos de simulação sócio-bio-econômico integrado como ferramenta para o desenvolvimento agrário na região sudoeste do Rio Grande Sul.

    Get PDF
    Suporte tecnológico tem sido oferecido aos produtores com a finalidade de aumentar a eficiência produtiva e fornecer subsídios para as suas tomadas de decisões; entretanto, os métodos tradicionais de pesquisa e extensão estão sendo cada vez mais questionados, principalmente quanto ao custo e tempo necessário para oferecer soluções aos problemas enfrentados pelos produtores.bitstream/item/109814/1/USO-DE-MODELOS-DE-SIMULACAO.pd

    Cuidados com a leitoa de reposição.

    Get PDF
    bitstream/item/59499/1/CUsersPiazzonDocuments14.pdfAcesso em: 13 jun. 2007
    corecore