22,283 research outputs found
Deformation method for generalized Abelian Higgs-Chern-Simons models
We present an extension of the deformation method applied to self-dual
solutions of generalized Abelian Higgs-Chern-Simons models. Starting from a
model defined by a potential and a non-canonical kinetic term
whose analytical domain wall solutions are
known, we show that this method allows to obtain an uncountable number of new
analytical solutions of new models defined by other functions
and . We present some examples of deformation functions
leading to new families of models and their associated analytic solutions.Comment: 6 pages, 10 figure
Analytical study of tunneling times in flat histogram Monte Carlo
We present a model for the dynamics in energy space of multicanonical
simulation methods that lends itself to a rather complete analytic
characterization. The dynamics is completely determined by the density of
states. In the \pm J 2D spin glass the transitions between the ground state
level and the first excited one control the long time dynamics. We are able to
calculate the distribution of tunneling times and relate it to the
equilibration time of a starting probability distribution. In this model, and
possibly in any model in which entering and exiting regions with low density of
states are the slowest processes in the simulations, tunneling time can be much
larger (by a factor of O(N)) than the equilibration time of the probability
distribution. We find that these features also hold for the energy projection
of single spin flip dynamics.Comment: 7 pages, 4 figures, published in Europhysics Letters (2005
Immunization and Aging: a Learning Process in the Immune Network
The immune system can be thought as a complex network of different
interacting elements. A cellular automaton, defined in shape-space, was
recently shown to exhibit self-regulation and complex behavior and is,
therefore, a good candidate to model the immune system. Using this model to
simulate a real immune system we find good agreement with recent experiments on
mice. The model exhibits the experimentally observed refractory behavior of the
immune system under multiple antigen presentations as well as loss of its
plasticity caused by aging.Comment: 4 latex pages, 3 postscript figures attached. To be published in
Physical Review Letters (Tentatively scheduled for 5th Oct. issue
Indicacao de cultivares de feijao para o Estado de Alagoas.
A cultura do feijao, no Estado, e explorada, na sua grande maioria, por pequenos produtores, em regime de subsistencia, com pouca adocao de tecnicas de cultivo e utilizacao de semente de baixo potencial produtivo. A indicacao de cultivares bem adaptadas ao meio e com caracteristicas favoraveis se constitui em objeto do presente estudo. O ensaio foi conduzido no Campo Experimental de Santana do Ipanema, AL, em solo Litolico Eutrofico, de textura arenosa. Foram testadas dez cultivares de feijao, em consorcio com 3 de feijao. O delineamento usado foi o de blocos ao acaso, com 4 repeticoes, tendo cada parcela uma area util de 12 2. Efetuou-se a adubacao basica, com aplicacao de 30-60-20 kg/ha de N, P2O5 e K2O, respectivamente, nas formas de sulfato de amonio, superfosfato simples e cloreto de potassio. As cultivares introduzidas, Gordo e Bagajo, destacaram-se das demais, com rendimentos superiores as regionais Vagem Roxa, Rim de Porco, Santana do Ipanema e Lages, cujas producoes foram: 1068, 865, 640, 613 e 591 kg/ha, respectivamente, em cultivo consorciado. Observou-se tambem que as cultivares que apresentaram com comportamento em consorcio, assim se mostraram quando isoladas
Ferramentas automatizadas para a manutenção e acesso a dados das Agências de Informação da Embrapa: apostila de treinamento.
Elementos de dados. Manipulação da estrutura da árvore. Preparação da árvore para o editor de conteúdo. Editor de conteúdo de nó. Pre-catalogação de recursos. Publicação do Site de uma Agência.bitstream/CNPTIA/9941/1/doc17.pdfAcesso em: 29 maio 2008
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