193 research outputs found
The N = 1 Supersymmetric Wong Equations and the Non-Abelian Landau Problem
A Lagrangian formulation is given extending to N = 1 supersymmetry the motion
of a charged point particle with spin in a non-abelian external field. The
classical formulation is constructed for any external static non-abelian SU(N)
gauge potential. As an illustration, a specific gauge is fixed enabling
canonical quantization and the study of the supersymmetric non-abelian Landau
problem. The spectrum of the quantum Hamiltonian operator follows in accordance
with the supersymmetric structure.Comment: 10 page
Influence of the Types of Fertilizers on the Economic Performance of the Market Garden Production in Parakou Town, Northern Benin
Given the pronounced degradation in recent years, it appears imperative to develop production techniques promoting conservation/improvement of the structure and composition of the soil. This study aims to analyze the influence of the types of fertilizers on the economic performance of the market garden production in the town of Parakou. This study is specifically interested in the culture of carrot. To achieve this, a survey was conducted among sixty (60) farmers chosen randomly in this Municipality. The data collected were related to demographics and spending and revenue generation according to the types of fertilizers (chemical and biological). These data were collected on the basis of a questionnaire addressed to individually sampled producers. The information collected was analyzed using SPSS software v. 20. It follows that the carrot production is economically and financially profitable in the town of Parakou. Moreover, economic performance indicators calculated (net margin, average labor productivity, internal rate of return and the benefit/cost) indicate that organic fertilizers improve more the profitability of this production
Alocação de recursos e rentabilidade das pesquisas originadas do Centro Nacional de Pesquisa de Soja.
Desenvolvimento da soja no Brasil; Beneficios gerados pela pesquisa no CNPSo; Propriedades da pesquisa e principais tecnologias geradas.bitstream/item/23241/1/Doc26.pd
The Cauchy problem on a characteristic cone for the Einstein equations in arbitrary dimensions
We derive explicit formulae for a set of constraints for the Einstein
equations on a null hypersurface, in arbitrary dimensions. We solve these
constraints and show that they provide necessary and sufficient conditions so
that a spacetime solution of the Cauchy problem on a characteristic cone for
the hyperbolic system of the reduced Einstein equations in wave-map gauge also
satisfies the full Einstein equations. We prove a geometric uniqueness theorem
for this Cauchy problem in the vacuum case.Comment: 83 pages, 1 figur
Local and Global Analytic Solutions for a Class of Characteristic Problems of the Einstein Vacuum Equations in the "Double Null Foliation Gauge"
The main goal of this work consists in showing that the analytic solutions
for a class of characteristic problems for the Einstein vacuum equations have
an existence region larger than the one provided by the Cauchy-Kowalevski
theorem due to the intrinsic hyperbolicity of the Einstein equations. To prove
this result we first describe a geometric way of writing the vacuum Einstein
equations for the characteristic problems we are considering, in a gauge
characterized by the introduction of a double null cone foliation of the
spacetime. Then we prove that the existence region for the analytic solutions
can be extended to a larger region which depends only on the validity of the
apriori estimates for the Weyl equations, associated to the "Bel-Robinson
norms". In particular if the initial data are sufficiently small we show that
the analytic solution is global. Before showing how to extend the existence
region we describe the same result in the case of the Burger equation, which,
even if much simpler, nevertheless requires analogous logical steps required
for the general proof. Due to length of this work, in this paper we mainly
concentrate on the definition of the gauge we use and on writing in a
"geometric" way the Einstein equations, then we show how the Cauchy-Kowalevski
theorem is adapted to the characteristic problem for the Einstein equations and
we describe how the existence region can be extended in the case of the Burger
equation. Finally we describe the structure of the extension proof in the case
of the Einstein equations. The technical parts of this last result is the
content of a second paper.Comment: 68 page
Produção e rentabilidade do eucaliptos em empresas florestais.
bitstream/CNPF-2009-09/32745/1/com_tec83.pd
Produção e rentabilidade de pínus em empresas florestais.
bitstream/CNPF-2009-09/32744/1/com_tec82.pd
Índice de qualidade participativo do sistema plantio direto para a região do Alto Uruguai, RS - IQP-RAU.
O Índice de Qualidade Participativo do Plantio Direto (IQP) é uma das ferramentas de gestão em desenvolvimento pela equipe da Rede de Pesquisa SoloVivo, coordenada pela Embrapa. Esse indicador auxilia a técnicos e produtores rurais na tomada de decisão com vistas de práticas agrícolas, que levam à melhoria da qualidade do manejo do solo em áreas sob Sistema Plantio Direto. O ajuste desse indicador para as condições edafoclimáticas e de mercado características da região do Alto Rio Uruguai, no Rio Grande do Sul, apenas foi possível com o efetivo apoio de técnicos da Emater/RS - ASCAR e de produtores rurais da região que auxiliaram o processo de avaliação de cada indicador componente do IQP, propondo entre outras mudanças, a adoção de novos limites críticos, tornando assim mais precisos e adequados aos sistemas de produção e arranjos produtivos adotados na região alguns desses componentes, valorizando a diversificação de culturas em detrimento de sucessões simples predominante no ambiente produtivo, incentivando práticas de conservação do solo e de nutrição equilibrada. Apresenta-se nesta publicação o Índice de Qualidade do Sistema Plantio Direto adaptado para a Região do Alto Uruguai (IQP-RAU), na expectativa de que a disponibilização desta ferramenta aos técnicos e produtores rurais contribua com o aprimoramento do manejo adotado em áreas manejadas sob SPD.bitstream/item/223586/1/Doc-190-online-2021.pd
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