22,410 research outputs found

    Efeitos de herbicida sobre animais em pastejo.

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    bitstream/item/57819/1/Animaispastejo0001.pd

    KMOS view of the Galactic Centre - II. Metallicity distribution of late-type stars

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    Knowing the metallicity distribution of stars in the Galactic Centre has important implications for the formation history of the Milky Way nuclear star cluster. However, this distribution is not well known, and is currently based on a small sample of fewer than 100 stars. We obtained near-infrared K-band spectra of more than 700 late-type stars in the central 4 pc^2 of the Milky Way nuclear star cluster with the integral-field spectrograph KMOS (VLT). We analyse the medium-resolution spectra using a full-spectral fitting method employing the G\"ottingen Spectral library of synthetic PHOENIX spectra. The derived stellar metallicities range from metal-rich [M/H]>+0.3 dex to metal-poor [M/H]<-1.0 dex, with a fraction of 5.2(^{+6.0}+{-3.1}) per cent metal-poor ([M/H]<-0.5 dex) stars. The metal-poor stars are distributed over the entire observed field. The origin of metal-poor stars remains unclear. They could originate from infalling globular clusters. For the metal-rich stellar population ([M/H]>0 dex) a globular cluster origin can be ruled out. As there is only a very low fraction of metal-poor stars in the central 4 pc^2 of the Galactic Centre, we believe that our data can discard a scenario in which the Milky Way nuclear star cluster is purely formed from infalling globular clusters.Comment: 18 pages, 9 Figures, accepted for publication in MNRA

    Valor nutritivo do mata-pasto (Senna obtusifolia (L.) Irwin & Barneby) em diferentes idades.

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    O mata-pasto (Senna obtusifolia (L.) Irwin & Barneby), leguminosa de larga ocorrência natural no Nordeste, apesar de não apreciada pelos ruminantes quando verde, é muito consumida quando naturalmente seca. Apresenta, portanto, a possibilidade de ser usada como feno, para diminuir a carência alimentar da época seca. Este trabalho teve como objetivo a determinação dos percentuais de proteína bruta (PB), fibra bruta (FB), extrato etéreo IEE), cálcio (Ca) e fósforo (P), na planta inteira, caule e folhas do mata-pasto, em diferentes idades. Coletaram-se, mensalmente, dos 30 aos 180 dias de idade, cinco amostras de 0,5 x 0,5 m para a análise da planta inteira e outras cinco para caules e folhas. A PB diminuiu com a idade das plantas, sendo maior nas folhas (11,75% - 28,63%) e menor nos caules (2,44% - 22,46%). A FB foi maior nos caules (29,50% - 48,50%) do que nas folhas (8,28% - 10,52%), aumentando com a idade. O EE pouco variou em relação às partes da planta, como tambem com a idade (2,91% - 3,34% nas folhas e 0,83% - 1,04% nos caules). O P decresceu com a idade, sendo de 0,16% - 0,28% nas folhas e 0,11% - 0,20% nos caules. O Ca foi também mais alto nas folhas (1,33% - 3,07%), onde aumentou com a idade, enquanto decresceu nos caules e na planta inteira. Todas as variáveis tiveram, na planta inteira, valores intermediários entre os observados nas folhas e nos caules. O mata-pasto é uma planta nutricionalmente adequada, com seu corte para fenação por volta de 120 dias.bitstream/item/35799/1/BP33.pd

    Avaliacao de acessos do genero Stylosanthes para a producao de feno.

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    bitstream/item/97559/1/PAND750001.pd

    Avaliacao da produtividade e do teor proteico de acessos de Stylosanthes.

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    Avaliacao de acessos de Stylosanthes, visando a selecao de materiais adaptados e produtivos.bitstream/item/97564/1/PAND800001.pd

    A Comprehensive Mechanism Reproducing the Mass and Mixing Parameters of Quarks and Leptons

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    It is shown that if, from the starting point of a universal rank-one mass matrix long favoured by phenomenologists, one adds the assumption that it rotates (changes its orientation in generation space) with changing scale, one can reproduce, in terms of only 6 real parameters, all the 16 mass ratios and mixing parameters of quarks and leptons. Of these 16 quantities so reproduced, 10 for which data exist for direct comparison (i.e. the CKM elements including the CP-violating phase, the angles θ12,θ13,θ23\theta_{12}, \theta_{13}, \theta_{23} in ν\nu-oscillation, and the masses mc,mμ,mem_c, m_\mu, m_e) agree well with experiment, mostly to within experimental errors; 4 others (ms,mu,md,mν2m_s, m_u, m_d, m_{\nu_2}), the experimental values for which can only be inferred, agree reasonably well; while 2 others (mν1,δCPm_{\nu_1}, \delta_{CP} for leptons), not yet measured experimentally, remain as predictions. In addition, one gets as bonuses, estimates for (i) the right-handed neutrino mass mνRm_{\nu_R} and (ii) the strong CP angle θ\theta inherent in QCD. One notes in particular that the output value for sin22θ13\sin^2 2 \theta_{13} from the fit agrees very well with recent experiments. By inputting the current experimental value with its error, one obtains further from the fit 2 new testable constraints: (i) that θ23\theta_{23} must depart from its "maximal" value: sin22θ230.935±0.021\sin^2 2 \theta_{23} \sim 0.935 \pm 0.021, (ii) that the CP-violating (Dirac) phase in the PMNS would be smaller than in the CKM matrix: of order only sinδCP0.31|\sin \delta_{CP}| \leq 0.31 if not vanishing altogether.Comment: 37 pages, 1 figur

    Estabelecimento de pastagens cultivadas, em area de chapada, na microrregiao de Valenca do Piaui.

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    Com base nas observacoes efetuadas, podem ser enumerados varios pontos importantes quando do estabelecimento de pastagem cultivada: 1) Controle da vegetacao arbustiva nao desejavel atraves do desmatamento com grade pesada, a uma profundidade adequada. Apos o desmatamento, uma ou duas gradagens com grade hidraulica sao necessarias para diminuir a presenca das invasoras herbaceas que pode, tambem prejudicar o estabelecimento das forrageiras. 2) Face a baixa fertilidade do solo deve ser feitas uma adubacao com fosforo e potassio para permitir o melhor estabelecimento da pastagem plantada. Aconselha-se que a distribuicao dos adubos sejam feitas em linhas, de modo a aumentar o seu aproveitamento pelas plantas e diminuir a fixacao pelo solo. 3)Alem destes cuidados, ainda ha que se considerar a quantidade e distribuicao das chuvas como fator decisivo quando da implantacao de uma pastagem.bitstream/item/95759/1/CT110001.pd

    Challenges and Solutions for Autonomous Robotic Mobile Manipulation for Outdoor Sample Collection

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    In refinery, petrochemical, and chemical plants, process technicians collect uncontaminated samples to be analyzed in the quality control laboratory all time and all weather. This traditionally manual operation not only exposes the process technicians to hazardous chemicals, but also imposes an economical burden on the management. The recent development in mobile manipulation provides an opportunity to fully automate the operation of sample collection. This paper reviewed the various challenges in sample collection in terms of navigation of the mobile platform and manipulation of the robotic arm from four aspects, namely mobile robot positioning/attitude using global navigation satellite system (GNSS), vision-based navigation and visual servoing, robotic manipulation, mobile robot path planning and control. This paper further proposed solutions to these challenges and pointed the main direction of development in mobile manipulation
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