1,215 research outputs found
The Noncommutative Anandan's Quantum Phase
In this work we study the noncommutative nonrelativistic quantum dynamics of
a neutral particle, that possesses permanent magnetic and electric dipole
momenta, in the presence of an electric and magnetic fields. We use the
Foldy-Wouthuysen transformation of the Dirac spinor with a non-minimal coupling
to obtain the nonrelativistic limit. In this limit, we will study the
noncommutative quantum dynamics and obtain the noncommutative Anandan's
geometric phase. We analyze the situation where magnetic dipole moment of the
particle is zero and we obtain the noncommutative version of the
He-McKellar-Wilkens effect. We demonstrate that this phase in the
noncommutative case is a geometric dispersive phase. We also investigate this
geometric phase considering the noncommutativity in the phase space and the
Anandan's phase is obtained.Comment: 15 pages, revtex4, version to appear in Physical Review
Insecta, Coleoptera, Elmidae, Amazon region
A list of Elmidae species from Amazon is presented. The list was prepared based on a literature surveyand examination of the entomological collection of Instituto Nacional de Pesquisas da Amazônia (INPA). The listincludes 102 species, with ten new occurrences recorded, being one for the Amazon (which includes areas ofBrazil, Bolivia, Colombia, Guyana, French Guyana, Peru, Suriname and Venezuela) three for the Amazonas state,and six for other localities in Brazil. Reports about species bibliography contents were also included, as well asavailable species municipalities distributional data
Manejo e exploração sustentável de florestas naturais tropicais: opções, restrições e alternativas.
Introdução; Conceito e manejo florestal e sustentabilidade; Características das florestas naturais tropicais; Formas de manejo florestal; Manejo de produtos não-madeireiros; Manejo de uso múltiplo; Manejo florestal em área com população; Modelo geral para pequena propriedade; condições gerais para o manejo florestal; Condições imediatas para implantação do manejo florestal.bitstream/CNPF-2009-09/40472/1/doc110.pd
Desempenho de genótipos de mandioca em um Argissolo eutrófico na região sudoeste da Amazônia.
Objetivou-se com esse trabalho avaliar diferentes genótipos de mandioca quanto ao desempenho agronômico e industrial para a região sudoeste amazônica, em Rondônia
Herding model and 1/f noise
We provide evidence that for some values of the parameters a simple agent
based model, describing herding behavior, yields signals with 1/f power
spectral density. We derive a non-linear stochastic differential equation for
the ratio of number of agents and show, that it has the form proposed earlier
for modeling of 1/f^beta noise with different exponents beta. The non-linear
terms in the transition probabilities, quantifying the herding behavior, are
crucial to the appearance of 1/f noise. Thus, the herding dynamics can be seen
as a microscopic explanation of the proposed non-linear stochastic differential
equations generating signals with 1/f^beta spectrum. We also consider the
possible feedback of macroscopic state on microscopic transition probabilities
strengthening the non-linearity of equations and providing more opportunities
in the modeling of processes exhibiting power-law statistics
MATHEMATICAL MODELING OF LEACHING PROCESS OF RED MUD IN ORDER TO OBTAIN THE KINETICS PARAMETERS
The use of the waste of the Bayer process, red mud, is due to its chemical and mineralogical composition that shows a material rich in oxides of iron, titanium and aluminum. Some studies conducted show that this waste can be applied as a source of alternative raw material for concentration and subsequent recovery of titanium compounds from an iron leaching process, which is present in higher amounts, about 30% by weight. To obtain a greater understanding about the leaching kinetics, the information of the kinetic data of this process is very important. In this context, the main objective of this work is the development of a mathematical model that is able to fit the experimental data (conversion / extraction iron, titanium and aluminum) of the leaching process by which is possible to obtain the main kinetic parameters such as the activation energy and the velocity of chemical reactions as well as the controlling step of the process. The development of the mathematical model was based on the model of core decreasing. The obtained model system of ordinary differential equations was able to fit the experimental data obtained from the leaching process, enabling the determination of the controlling step, the rate constants and the activation energies of the leaching process
Identificação de estirpes de Rhizobium competitivas para nodulação efetiva do feijoeiro nos cerrados.
Efeito de banho de ultrassom de baixa frequência sobre a germinação e vigor de sementes de gliricídia (Gliricidia sepium).
Objetivou-se avaliar o efeito do uso do ultrassom de baixa frequência sobre a germinação e vigor de sementes de gliricídia (Gliricidia sepium)
Avaliação da qualidade da água de poços freáticos de uma área do estuário do Rio Vaza Barris.
bitstream/CPATC/19782/1/f_20_2007.pd
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