2,118 research outputs found

    The Noncommutative Anandan's Quantum Phase

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    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

    Violation of the Ikeda sum rule and the self-consistency in the renormalized quasiparticle random phase approximation and the nuclear double-beta decay

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    The effect of the inclusion of ground state correlations into the QRPA equation of motion for the two-neutrino double beta (ββ2ν\beta\beta_{2\nu}) decay is carefully analyzed. The resulting model, called renormalized QRPA (RQRPA), does not collapse near the physical value of the nuclear force strength in the particle-particle channel, as happens with the ordinary QRPA. Still, the ββ2ν\beta\beta_{2\nu} transition amplitude is only slightly less sensitive on this parameter in the RQRPA than that in the plain QRPA. It is argued that this fact reveals once more that the characteristic behaviour of the ββ2ν\beta\beta_{2\nu} transition amplitude within the QRPA is not an artifact of the model, but a consequence of the partial restoration of the spin-isospin SU(4)SU(4) symmetry. It is shown that the price paid for bypassing the collapse in the RQRPA is the violation of the Ikeda sum rule.Comment: 16 pages, latex, 3 postscript figure

    Initial Biomass Production and Soluble Carbohydrate Partitioning of Contrasting Elephantgrass Genotypes

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    The initial growth and soluble carbohydrate (SC) partitioning were examined in the following classes of elephantgrass (Pennisetum purpureum Schum.) genotypes: Dwarf (Anão, Mott and Roxo); Cameroon (Cameroon, Cameroon Piracicaba and Vruckwona); Embrapa hybrids (CNPGL F27-5 and Pioneiro); Interspecific hybrids (Hexaploide 201, Mercker X 23-A and Napier X 23-A; Mercker (Mercker Comum, Mercker Pinda and Teresópolis); and Napier (E.C. Itapemirim, Mineiro and Napier). After a 60-day growing period, total, leaf, stem and root FW and DW and stem, stem base, leaf and root SC content were determined. Cameroon-class cultivars showed the highest leaf and stem DW and whole stem SC levels. Cv. Napier exhibited the highest stem base SC content, suggesting superior regrowth capability. Dwarf-class cultivars showed reduced leaf DW and low stem base SC levels, indicating poor regrowth potential. Embrapa hybrids were high on both leaf and root SC contents, and the implications of such an attribute need to be verified

    Effect of RBC stiffness on microhaemodynamics

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    Modelagem morfodinâmica do transporte de sedimento de fundo em ambientes costeiros

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    O transporte de sedimentos em ambientes aquáticos costeiros depende muito da hidrodinâmica local, que é forçada pela maré astronômica e meteorológica, pelas ondas, e pela intensidade e direção do vento. Ações planejadas ou não-planejadas nesses ambientes podem desencadear problemas erosivos comprometendo as construções na orla praial, turismo, lazer, operações de embarque em portos, dentre outros. Neste trabalho é realizado o estudo das mudanças morfodinâmicas induzidos por ondas de superfície. O modelo de ondas é linear e do tipo águas rasas, que considera o efeito de atrito com o leito. Sem perda de generalidade, o transporte de sedimento suspenso não é considerado. Para as mudanças morfodinâmicas do leito é considerada a equação de conservação volumétrica de sedimento de fundo. Inicialmente, diferentes esquemas em diferenças finitas foram implementadas para solucionar a equação para o transporte de sedimento (variação morfológica de fundo costeiro) submetido a um escoamento uni-direcional. A análise dos resultados obtidos mostrou que o esquema de Warming-Beam para discretizar a equação de transporte de sedimento foi que melhor representou a solução analítica. O modelo morfodinâmico foi acoplado ao modelo linear de onda do tipo águas rasas. Dos resultados analisados, verificou-se um movimento harmônico do banco de sedimento que aumenta com o aumento do período da onda
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