10,671 research outputs found

    Phenomenological Renormalization Group Methods

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    Some renormalization group approaches have been proposed during the last few years which are close in spirit to the Nightingale phenomenological procedure. In essence, by exploiting the finite size scaling hypothesis, the approximate critical behavior of the model on infinite lattice is obtained through the exact computation of some thermal quantities of the model on finite clusters. In this work some of these methods are reviewed, namely the mean field renormalization group, the effective field renormalization group and the finite size scaling renormalization group procedures. Although special emphasis is given to the mean field renormalization group (since it has been, up to now, much more applied an extended to study a wide variety of different systems) a discussion of their potentialities and interrelations to other methods is also addressed.Comment: Review Articl

    Spillover and diffraction sidelobe contamination in a double-shielded experiment for mapping Galactic synchrotron emission

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    We have analyzed observations from a radioastronomical experiment to survey the sky at decimetric wavelengths along with feed pattern measurements in order to account for the level of ground contamination entering the sidelobes. A major asset of the experiment is the use of a wire mesh fence around the rim-halo shielded antenna with the purpose of levelling out and reducing this source of stray radiation for zenith-centered 1-rpm circular scans. We investigate the shielding performance of the experiment by means of a geometric diffraction model in order to predict the level of the spillover and diffraction sidelobes in the direction of the ground. Using 408 MHz and 1465 MHz feed measurements, the model shows how a weakly-diffracting and unshielded antenna configuration becomes strongly-diffracting and double-shielded as far-field diffraction effects give way to near-field ones. Due to the asymmetric response of the feeds, the orientation of their radiation fields with respect to the secondary must be known a priori before comparing model predictions with observational data. By adjusting the attenuation coefficient of the wire mesh the model is able to reproduce the amount of differential ground pick-up observed during test measurements at 1465 MHz.Comment: 14 pages, 17 eps + 1 gif figures and 4 Tables. Accepted for publication in A&AS. Fig.7 available at full resolution from http://www.das.inpe.br/~tello/publications.ht

    Modelagem da hidrografia em planos de manejo e critérios para definição de árvores em APP pelo Modeflora.

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    Novas tecnologias, sendo advindas do geoprocessamento e do sensoriamento remoto, vêm sendo desenvolvidas a fim de auxiliar no processo de delimitação das APPs e demarcação das árvores. No entanto, faltam estudos para investigar e comprovar sua eficácia. Não há registro de trabalhos, publicados no Brasil, que utilizem diferentes metodologias na definição de APPs para avaliá-las. O presente trabalho teve como objetivo propor uma metodologia precisa para o mapeamento de áreas de preservação permanente e definição de árvores protegidas e exploráveis na região de influência das APPs, comprovando a sua aplicabilidade nos PMFS.bitstream/CPAF-AC-2010/23132/1/circtec-n50.pd

    Basin structure in the two-dimensional dissipative circle map

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    Fractal basin structure in the two-dimensional dissipative circle map is examined in detail. Numerically obtained basin appears to be riddling in the parameter region where two periodic orbits co-exist near a boundary crisis, but it is shown to consist of layers of thin bands.Comment: published in J. Phys. Soc. Jpn., 72, 1943-1947 (2003

    Germinação de sementes de malícia e salsa em diferentes condições de temperatura e luz.

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    Resumo também publicado em: REUNIÃO ANUAL DA SOCIEDADE BRASILEIRA DE ZOOTECNIA, 37., 2000, Viçosa, MG. Resumos dos trabalhos apresentados. Viçosa, MG: Sociedade Brasileira de Zootecnia, 2000. p. 98

    Plant crude extracts inhibit oviposition of bovine tick Rhipicephalus (Boophilus) microplus.

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    Parasitism by the bovine tick Rhipicephalus (Boophilus) microplus is one of the main barriers for the development of livestock.04 a 07 dez. EBEQ. Pôster
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