6,408 research outputs found

    Irrigated rice area estimation using remote sensing techniques: Project's proposal and preliminary results

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    The development of a methodology for annual estimates of irrigated rice crop in the State of Rio Grande do Sul, Brazil, using remote sensing techniques is proposed. The project involves interpretation, digital analysis, and sampling techniques of LANDSAT imagery. Results are discussed from a preliminary phase for identifying and evaluating irrigated rice crop areas in four counties of the State, for the crop year 1982/1983. This first phase involved just visual interpretation techniques of MSS/LANDSAT images

    Efeitos de micronutrientes em capim colonião (Panicum maximum, Jacq.) cultivado num solo de campo cerrado.

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    Utilizando-se de um solo de campo cerrado (Latosol Vermelho Amarelo - fase arenosa), que nunca recebeu qualquer adubação, instalou-se este experimento em vasos, em casa de vegetação, com a finalidade de se verificar a influencia dos micronutrientes: Manganês, molibdenio, cobre, zinco e boro, sobre o desenvolvimento do capim colonia

    Identifying the Higgs Boson in Electron--Photon Collisions

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    We analyze the production and detection of the Higgs boson in the next generation of linear e+ee^+e^- colliders operating in the eγe\gamma mode. In particular, we study the production mechanism e+γeγγe+He + \gamma \rightarrow e \gamma \gamma \rightarrow e + H, where one photon is generated via the laser backscattering mechanism, while the other is radiated via the usual bremsstrahlung process. We show that this is the most important mechanism for Higgs boson production in a 500500 GeV eγe\gamma collider for M_H\raisebox{-.4ex}{\rlap{\sim}} \raisebox{.4ex}{>}140 GeV. We also study the signals and backgrounds for detection of the Higgs in the different decay channels, bbˉb \bar b, W+WW^+W^-, and ZZZZ, and suggest kinematical cuts to improve the signature of an intermediate mass Higgs boson.Comment: (REVTEX 2.0, 12 pages and 9 figures available upon request, Preprint MAD/PH/753

    On the resonance eigenstates of an open quantum baker map

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    We study the resonance eigenstates of a particular quantization of the open baker map. For any admissible value of Planck's constant, the corresponding quantum map is a subunitary matrix, and the nonzero component of its spectrum is contained inside an annulus in the complex plane, zminzzmax|z_{min}|\leq |z|\leq |z_{max}|. We consider semiclassical sequences of eigenstates, such that the moduli of their eigenvalues converge to a fixed radius rr. We prove that, if the moduli converge to r=zmaxr=|z_{max}|, then the sequence of eigenstates converges to a fixed phase space measure ρmax\rho_{max}. The same holds for sequences with eigenvalue moduli converging to zmin|z_{min}|, with a different limit measure ρmin\rho_{min}. Both these limiting measures are supported on fractal sets, which are trapped sets of the classical dynamics. For a general radius zmin<r<zmax|z_{min}|< r < |z_{max}|, we identify families of eigenstates with precise self-similar properties.Comment: 32 pages, 2 figure

    Order of strength exercises on the performance of judo athletes

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    OBJETIVO: El objetivo fue investigar el efecto del orden distintas de ejercicios de fuerza para extremidades superiores e inferiores en el rendimiento específico de judokas junior. MÉTODO: Se divide una muestra de 39 atletas masculinos en tres grupos: Experimental-EG1; EG2 y Control. Los Grupos realizaron ejercicios de fuerza máxima y potencia con intensidades del 80-90% para 12 semanas de intervención. El orden de los ejercicios para el EG1 fue del de extremidades superiores primero e inferiores después. El EG2 realiza los mismos ejercicios en secuencia inversa. Se utilizó la Prueba Especial Judo Fitness (SJFT) para evaluación. RESULTADOS: Los experimentos intra e inter grupos muestran diferencias (p<0.05) en los derribos-caídas y en el índice SJFT, con EG2 mostrando mejores resultados. CONCLUSIONES: Las variables de SJFT tuvieron mejores resultados en el orden de ejercicios seguidos por el EG2OBJECTIVE: To analyze the effect of strength exercises using different orders for upper and lower limbs on the specific performance of junior judo athletes. METHODS: 39 male athletes were divided into three groups: experimental- EG1, experimental-EG2 and control group. Experimental groups performed with intensities 80-90% of strength and power for 12 weeks. The exercise-order for EG1 followed an upper to lower limb sequence and EG2 performed the same exercises in reverse. The Special Judo Fitness Test (SJFT) was used in the assessment. RESULTS: Experimental intra and inter-groups showed differences (p<0.05) in the throws-falls and SJFT-index, but the EG2 showed best results. CONCLUSIONS: The SJFT-variables had better results to exercises order in EG

    Quartic Anomalous Couplings in γγ\gamma\gamma Colliders

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    We study the constraints on the vertices W+WZγW^+W^- Z\gamma, W+WγγW^+W^-\gamma\gamma, and ZZγγZZ\gamma\gamma that can be obtained from triple-gauge-boson production at the next generation of linear e+ee^+e^- colliders operating in the γγ\gamma\gamma mode. We analyze the processes γγW+WV\gamma\gamma \to W^+W^-V (V=ZV=Z, or γ\gamma) and show that these reactions increase the potential of e+ee^+e^- machines to search for anomalous four-gauge-boson interactions.Comment: 15 pages, Latex file using ReVteX, 4 uufiled figures include

    Two-photon final states in peripheral heavy ion collisions

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    We discuss processes leading to two photon final states in peripheral heavy ion collisions at RHIC. Due to the large photon luminosity we show that the continuum subprocess γγγγ\gamma \gamma \to \gamma \gamma can be observed with a large number of events. We study this reaction when it is intermediated by a resonance made of quarks or gluons and discuss its interplay with the continuum process, verifying that in several cases the resonant process ovewhelms the continuum one. It is also investigated the possibility of observing a scalar resonance (the σ\sigma meson) in this process. Assuming for the σ\sigma the mass and total decay width values recently reported by the E791 Collaboration we show that RHIC may detect this particle in its two photon decay mode if its partial photonic decay width is of the order of the ones discussed in the literature.Comment: 10 pages, 8 figure

    Relação de Meloidogyne arenaria com o desenvolvimento radicular do porta-enxerto SO4. de videira

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    O objetivo deste trabalho foi avaliar a relação entre a presença de Meloidogyne arenaria no solo e o desenvolvimento radicular do porta-enxerto SO4 de videira. Foram avaliados, além deste porta-enxerto, o ?Harmony? e o ?IAC 766? por serem amplamente utilizados na vitivinicultura do Submédio do Vale do São Francisco. O enraizamento foi feito em solo autoclavado contido em sacos para formação de mudas. Após 40 dias, as mudas foram transplantadas para vasos com capacidade de 20 L, conforme os seguintes tratamentos: 1) solo natural -- infestado com M. arenaria -- 2) solo autoclavado e com inoculação das mudas e 3) solo autoclavado e sem inoculação das mudas com M. arenaria. Após 6 meses, nenhuma anormalidade foi observada, visualmente, no sistema radicular dos porta-enxertos avaliados. Observou-se que o nematoide não se multiplicou de forma diferenciada nos três porta-enxertos, mas que o porta-enxerto ?Harmony? pode vir a se tornar uma opção de substituição do ?SO4? por se apresentar com tendências a maior vigor do sistema radicular, visto não ter ocorrido diferença significativa no número de ovos quantificados nos três porta-enxertos

    Apresentando alguns aspectos históricos do desenvolvimento da lógica clássica, ciência das idéias e dos processos da mente

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    Lógica é a ciência que tem por objeto determinar, entre as operações intelectuais orientadas para o conhecimento da verdade, as que são válidas e as que não são. Estuda os processos e as condições de verdade de todo e qualquer raciocínio. O conhecimento só é científico quando, além de universal, é metódico e sistemático, ou seja, lógico. Assim, a lógica se entende como método, ou caminho que as ciências trilham para determinar e conhecer seu objeto, e como característica geral do conhecimento científico
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