1,183 research outputs found

    Primary cosmic ray spectrum in the 10 to the 12th power - 10 to the 16th power eV energy range from the NUSEX experiment

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    A primary cosmic ray spectrum was derived which fits both experimental multiple muon rates and the all-nucleon flux derived from the single muon intensities underground. In the frame of the interaction model developed by Gaisser, Elbert and Stanev, it is possible to reproduce NUSEX muon data with a primary composition in which the iron spectrum is only slightly flatter than the proton one. This result rules out the popular idea that the primary composition varies drastically with increasing energy, leading to the dominance of heavier nuclei at energies 10 to the 15th power to 10 to the 16th power eV

    Avaliação da fertilidade dos solos do Distrito Federal.

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    O SNLCS tem procurado ampliar o alcance e a utilização prática, dos dados obtidos através dos levantamentos de solos que realiza. Prosseguindo as pesquisas que objetivam a elaboração do mapa de solos do Brasil a nível de reconhecimento, esta entidade vem complementando seus trabalhos com mapas de aptidão agrícola das terras, em relação com diferentes tipos de manejo e culturas. Dentro dos parâmetros usados para definir a aptidão agrícola dos solos, a fertilidade e o mais facilmente controlável e aquele cuja alteração modifica mais sensivelmente a produtividade das terras. Por outro lado, os mapas de aptidão, pela sua natureza, não mostram claramente as limitações de uso devido unicamente ao nível de fertilidade das terras. Tal informação é de grande importância ao estudo de viabilidade econômica de projetos agropecuários, por permitir estimar a necessidade de fertilizantes e corretivos para determinada área. A análise conjunta dos mapas de classificação e aptidão agrícola e ainda de uma avaliação da fertilidade dos solos, daria aos usuários dos trabalhos de levantamento uma visão mais completa dos recursos disponíveis, facilitando as decisões quanto ao tipo de exploração agrícola e ao sistema de manejo mais adequado em cada caso. O presente projeto propõe a complementação de cada trabalho de levantamento com uma avaliação e quantificação da fertilidade, cuja precisão e confiabilidade serão tanto maiores quanto maior for o nível de detalhe do levantamento de solos em que seja baseado.bitstream/item/62835/1/CNPS-BOL.-TEC.-74-80.pdf; bitstream/item/125962/1/Avaliacao-da-Fertilidade-dos-Solos-do-Distrito-Federal.pdfAcompanha 1 mapa, color. Escala 1:100.000

    The cusp effect in eta' --> eta pi pi decays

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    Strong final-state interactions create a pronounced cusp in eta' --> eta pi0 pi0 decays. We adapt and generalize the non-relativistic effective field theory framework developed for the extraction of pi pi scattering lengths from K --> 3 pi decays to this case. The cusp effect is predicted to have an effect of more than 8% on the decay spectrum below the pi+ pi- threshold.Comment: 11 pages, 8 figures; comment added, typos corrected, version published in Eur. Phys. J.

    A Negishi Approach to Recursive Contracts

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    In this paper, we argue that a large class of recursive contracts can be studied by means of the conventional Negishi method. A planner is responsible for prescribing current actions along with a distribution of future utility values to all agents, so as to maximize their weighted sum of utilities. Under convexity, the method yields the exact efficient frontier. Otherwise, the implementation requires contracts be contingent on publicly observable random signals uncorrelated to fundamentals. We also provide operational first-order conditions for the characterization of efficient contracts. Finally, we compare extensively our approach with the dual method established in the literature

    Garnierite Mineralization from Falcondo Ni-Laterite Deposit (Dominican Republic)

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    Mine geologists use the term "garnierite" for the green Ni-rich silicate minerals that occur in many Ni-laterite deposits. However, garnierite is not a mineral species recognized by the Commission on New Mineral and Mineral Names (CNMMN). Actually, garnierite is a general name for the NiMg hydrosilicates that usually occur as an intimate mixture that commonly includes two or more of the following minerals: serpentine, talc, sepiolite, smectite, and chlorite (e.g. Brindley and Hang, 1973; Springer, 1974; Brindley et al., 1979; Gleeson et al., 2004)

    A global fit to determine the pseudoscalar mixing angle and the gluonium content of the eta' meson

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    We update the values of the eta-eta' mixing angle and of the eta' gluonium content by fitting our measurement R_phi = BR(phi to eta' gamma)/ BR(phi to eta gamma) together with several vector meson radiative decays to pseudoscalars (V to P gamma), pseudoscalar mesons radiative decays to vectors (P to V gamma) and the eta' to gamma gamma, pi^0 to gamma gamma widths. From the fit we extract a gluonium fraction of Z^2_G = 0.12 +- 0.04, the pseudoscalar mixing angle psi_P = (40.4 +- 0.6) degree and the phi-omega mixing angle psi_V = (3.32 +- 0.09) degree. Z^2_G and psi_P are fairly consistent with those previously published. We also evaluate the impact on the eta' gluonium content determination of future experimental improvements of the eta' branching ratios and decay width.Comment: 13 pages, 7 figures to submit to JHE

    Determination of CP and CPT violation parameters in the neutral kaon system using the Bell-Steinberger relation and data from the KLOE experiment

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    We present an improved determination of the CP and CPT violation parameters Re(epsilon) and Im(delta) based on the unitarity condition (Bell-Steinberger relation) and on recent results from the KLOE experiment. We find Re(epsilon) = (159.6 \pm 1.3)10^-5 and Im(delta) = (0.4 \pm 2.1)10^-5, consistent with no CPT violation.Comment: Submitted to JHE
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