1,841 research outputs found

    Maximal correlation between flavor entanglement and oscillation damping due to localization effects

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    Localization effects and quantum decoherence driven by the mass-eigenstate wave packet propagation are shown to support a statistical correlation between quantum entanglement and damped oscillations in the scenario of three-flavor quantum mixing for neutrinos. Once the mass-eigenstates that support flavor oscillations are identified as three-{\em qubit} modes, a decoherence scale can be extracted from correlation quantifiers, namely the entanglement of formation and the logarithmic negativity. Such a decoherence scale is compared with the coherence length of damped oscillations. Damping signatures exhibited by flavor transition probabilities as an effective averaging of the oscillating terms are then explained as owing to loss of entanglement between mass modes involved in the relativistic propagation.Comment: 13 pages, 03 figure

    Using mixed data in the inverse scattering problem

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    Consider the fixed-ℓ\ell inverse scattering problem. We show that the zeros of the regular solution of the Schr\"odinger equation, rn(E)r_{n}(E), which are monotonic functions of the energy, determine a unique potential when the domain of the energy is such that the rn(E)r_{n}(E) range from zero to infinity. This suggests that the use of the mixed data of phase-shifts {δ(ℓ0,k),k≥k0}∪{δ(ℓ,k0),ℓ≥ℓ0}\{\delta(\ell_0,k), k \geq k_0 \} \cup \{\delta(\ell,k_0), \ell \geq \ell_0 \}, for which the zeros of the regular solution are monotonic in both domains, and range from zero to infinity, offers the possibility of determining the potential in a unique way.Comment: 9 pages, 2 figures. Talk given at the Conference of Inverse Quantum Scattering Theory, Hungary, August 200

    Caracterização biomecânica do gesto de alcançar em individuos pós Acidente Vascular Encefálico

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    É objectivo deste trabalho caracterizar biomecanicamente o gesto de alcançar em indivíduos pós Acidente Vascular Encefálico. A amostra é constituída por 4 indivíduos sem patologia do foro neuro-músculo-esquelético e 4 indivíduos com confirmação imagiológica do diagnóstico de AVE único e unilateral no território da artéria cerebral média, há pelo menos 3 meses; ausência de neglet; ausência de alterações visuais, perceptivas ou cognitivas e capacidade de realizar movimento activo no membro superior predominantemente afectado de pelo menos 15º no ombro e cotovelo. A partir de uma posição de sentado pré-definida, cada indivíduo foi instruído a executar a tarefa funcional de alcançar um alvo (copo com sumo), colocado sobre uma mesa, no limite anatómico da distância de alcance funcional da mão. Para a análise cinemática foram usadas 4 câmaras dispostas duas a duas para avaliação do movimento de cada um dos membros superiores. Foram colocados marcadores reflectores nas seguintes estruturas ósseas: esterno; acrómio (bilateralmente); epicôndilo lateral; processo estilóide do cúbito, 3º metacarpo e grande trocânter. Foi também colocado um marcador no objecto-alvo. Recorreu-se ao software APAS para análise das seguintes variáveis cinemáticas: tempo de execução do movimento, velocidade máxima da mão, unidades de movimento, trajectória (através do índex de curvatura) e extensão do cotovelo. Verificou-se que no grupo de indivíduos com AVE comparativamente ao grupo de indivíduos sem patologia, o tempo de execução do movimento foi superior (5,8±2,48 e 0,9±0,22 respectivamente), a velocidade máxima da mão foi inferior (101,7±32,62 e 153,3±56,32 respectivamente), o número de unidades de movimento foi superior (6,3±1,50 e 2,5±0,58 respectivamente), o índex de curvatura foi superior (1,8±0,54 e 1,2±0,1 respectivamente) e a amplitude de extensão do cotovelo foi inferior (15,3±16,48 e 50,2±6,72 respectivamente). Os indivíduos com AVE apresentam alterações nos parâmetros cinemáticos analisados, quando comparados com indivíduos sem patologia

    Anisotropic diffusion in continuum relaxation of stepped crystal surfaces

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    We study the continuum limit in 2+1 dimensions of nanoscale anisotropic diffusion processes on crystal surfaces relaxing to become flat below roughening. Our main result is a continuum law for the surface flux in terms of a new continuum-scale tensor mobility. The starting point is the Burton, Cabrera and Frank (BCF) theory, which offers a discrete scheme for atomic steps whose motion drives surface evolution. Our derivation is based on the separation of local space variables into fast and slow. The model includes: (i) anisotropic diffusion of adsorbed atoms (adatoms) on terraces separating steps; (ii) diffusion of atoms along step edges; and (iii) attachment-detachment of atoms at step edges. We derive a parabolic fourth-order, fully nonlinear partial differential equation (PDE) for the continuum surface height profile. An ingredient of this PDE is the surface mobility for the adatom flux, which is a nontrivial extension of the tensor mobility for isotropic terrace diffusion derived previously by Margetis and Kohn. Approximate, separable solutions of the PDE are discussed.Comment: 14 pages, 1 figur

    Effect of the presence of two commercial adsorbents in animal feed on Aflatoxin B1 determination by ELISA kit test.

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    A rapid AFB1 detection method by ELISA kit test was used on feedstuff samples, and compared to an HPLC method, to verify if the presence of clay-adsorbent (SA) could cause erroneous quantification of the toxin. Samples were obtained using two AFB1-contaminated feedstuffs (7.92 and 17.58 µg/kg for low and high contaminated feeds; LC and HC respectively), added either one of two commercial SAs (Atox® and Myco AD) and three different inclusion doses (0, 10 and 20 g/kg, respectively for CTR, 1% and 2% doses). The HPLC and ELISA data were compared in CTR samples with a paired t-test. The AFB1 recoveries, performed with ELISA, were analysed as a completely randomized design using a 2×2×3 factorial arrangement. The ELISA method tended to underestimate the AFB1 concentrations with respect to the HPLC method, both in HC (P=0.050) and in LC (P<0.001) feedstuffs. A more drastic reduction (P<0.001) was observed when SAs were included in the two feedstuffs. In particular, Atox® determined an AFB1 recovery of 15,5% in HC and 7,6% in LC (1% dose) and of 11,1% in HC and 8,4% in LC (2% dose). Less severe penalisation were observed when Myco AD was added to feeds

    Iagttagelser og Bemærkninger vedrørende Oldenborrerne.

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    Iagttagelser og Bemærkninger vedrørende Oldenborrerne
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