9,565 research outputs found

    Integraçao reduzida para problemas advectivos-difusivos escalares discretizados pela formulaçao Supg com operador de captura de descontinuidade

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    Este trabalho apresenta una técnica de controle das oscilaçoes esgúrias que podein surgir quando as integrais provenientes da discretizaçao de problemas escalares advectivos-difusivos em regime permanente pela formulaçao SUPG com operador de captura de descontinuidades, sao avaliadas utilizamdo-se um ponto de quadratura de Gauss. Os termos de correçao saoo obtidos a partir do princípio variacional de Hu-Washizu. Diversos exeinplos numéricos sao apresentados de forma a validar a técnica proposta. REDUCED INTEGRATION FOR STEADY ADVECTIVE-DIFFUSIVE PROBLEMS DISCRETIZED BY THE SUPG FORMULATION WITH DISCONTINUITY-CAPTURING SUMMARY This worlk presents a technique to control thee spurious oscillations that may appear when the integrals arising from the discretization of scalar steady-state advective-diffusive problems by the SUPG formulation with discontinuity-capturing are evaluated usiilg one-point Gaussian quadrature. Tlie correction terms are clerived froin a Hu-Wasl-iizu variational formulation. Severa1 numerical esamples a.re slzown, validating the proposed technique.Peer Reviewe

    Frustration-induced quantum phase transitions in a quasi-one-dimensional ferrimagnet: Hard-core boson map and the Ton ks-Girardeau limit

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    We provide evidence of a superfluid-insulator transition (SIT) of magnons in a quasi-one-dimensional quantum ferrimagnet with {\it isotropic} competing antiferromagnetic spin interactions. This SIT occurs between two distinct ferrimagnetic phases due to the frustration-induced closing of the gap to a magnon excitation. It thus causes a coherent superposition of singlet and triplet states at lattice unit cells and a power-law decay on the staggered spin correlation function along the transverse direction to the spontaneous magnetization. A hard-core boson map suggests that asymptotically close to the SIT the magnons attain the Tonks-Girardeau limit. The quantized nature of the condensed singlets is observed before a first-order transition to a singlet magnetic spiral phase accompanied by critical antiferromagnetic ordering. In the limit of strong frustration, the system undergoes a decoupling transition to an isolated gapped two-leg ladder and a critical single linear chain

    Expressão de genes ligados à maciez da carne em bovinos da raça Nelore.

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    Dentre as características da carne, a maciez é a mais desejada pelo consumidor. Bovinos de origem Bos taurus indicus são conhecidos por produzirem carne de menor maciez quando comparado às raças de origem taurina. O objetivo do estudo foi avaliar a expressão dos genes codificadores de proteínas da família ?heat shock? (CRYAB, HSPB1 e DNAJA1) em bovinos da raça Nelore (Bos taurus indicus). A expressão do gene CRYAB foi associada à maciez aos sete (P=0,003) e 14 dias (P=0,01) de maturação, e do gene HSPB1 associado à força de cisalhamento 24 horas (P=0,04) após abate e aos 7 (P=0,003) e 14 dias (P=003) de maturação. Baseado nos resultados, é possível sugerir que os genes CRYAB e HSBP1 podem ser potenciais marcadores de maciez da carne em bovinos da raça Nelore

    Neutral heavy lepton production at next high energy e+e−e^+e^- linear colliders

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    The discovery potential for detecting new heavy Majorana and Dirac neutrinos at some recently proposed high energy e+e−e^+e^- colliders is discussed. These new particles are suggested by grand unified theories and superstring-inspired models. For these models the production of a single heavy neutrino is shown to be more relevant than pair production when comparing cross sections and neutrino mass ranges. The process e+e−⟶νe±W∓ e^+e^- \longrightarrow {\nu} e^{\pm} W^{\mp} is calculated including on-shell and off-shell heavy neutrino effects. We present a detailed study of cross sections and distributions that shows a clear separation between the signal and standard model contributions, even after including hadronization effects.Comment: 4 pages including 15 figures, 1 table. RevTex. Accepted in Physical Review
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