1,158 research outputs found

    Aumento de Resolução Temporal de Sequências de Imagens do Trato Vocal por meio de Registro das Imagens

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    O imageamento por ressonância magnética tem sido bastanteutilizado no estudo da produção da fala. Sequências de imagens do trato vocal adquiridas durante a emissão de palavras e fonemas permitem a identificação dinâmica das formas assumidas por este tubo acústico. Entretanto, é importante ressaltar que as resoluções espacial e temporal necessárias para a identificação do movimento dos articuladores da fala variam de acordo com a velocidade e localidade desse movimento, e tal informação não é conhecida a priori. Abordagens existentes procuram aprimorar a resolução das sequências de imagens melhorando o processo de aquisição ou utilizando meios de aquisição mais potentes, o que pode ser financeiramente inviável. O método proposto neste artigo procura melhorar a resolução temporal por meio de um método de registro não-rígido proposto na literatura. O movimento identificado pelo registro permite o aumento de resolução temporal por meio de uma técnica de interpolação por compensação de movimento. O movimento presente em toda a sequência é considerado na geração de cada imagem intermediária. Dessa forma, o movimento dos articuladores da fala nessas imagens é coerente com o movimento presente em toda a sequência. Os resultados indicam a eficiência do método proposto

    Universality of Frequency and Field Scaling of the Conductivity Measured by Ac-Susceptibility of a Ybco-Film

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    Utilizing a novel and exact inversion scheme, we determine the complex linear conductivity σ(ω)\sigma (\omega ) from the linear magnetic ac-susceptibility which has been measured from 3\,mHz to 50\,MHz in fields between 0.4\,T and 4\,T applied parallel to the c-axis of a 250\,nm thin disk. The frequency derivative of the phase σ′′/σ′\sigma ''/\sigma ' and the dynamical scaling of σ(ω)\sigma (\omega) above and below Tg(B)T_g(B) provide clear evidence for a continuous phase transition at TgT_g to a generic superconducting state. Based on the vortex-glass scaling model, the resulting critical exponents ν\nu and zz are close to those frequently obtained on films by other means and associated with an 'isotropic' vortex glass. The field effect on σ(ω)\sigma(\omega) can be related to the increase of the glass coherence length, ξg∼B\xi_g\sim B.Comment: 8 pages (5 figures upon request), revtex 3.0, APK.94.01.0

    Factors related to tinnitus and hyperacusis handicap in older people.

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    OBJECTIVE: The aim was to assess factors related to tinnitus and hyperacusis handicap in older people. DESIGN: Retrospective cross-sectional. STUDY SAMPLE: Data were gathered for 184 patients with an average age of 69 years. RESULTS: Tinnitus handicap as measured via the Tinnitus Handicap Inventory (THI) was significantly predicted by tinnitus annoyance as measured via the visual analogue scale (VAS) (regression coefficient, b = 2.9, p < 0.001) and the effect of tinnitus on the patient's life as measured via the VAS (b = 3.9, p < 0.001). Hyperacusis handicap as measured via the Hyperacusis Questionnaire (HQ) was significantly predicted by the score on the depression subscale of the Hospital Anxiety and Depression Scale (HADS) (b = 0.8, p < 0.001) and to a small extent by the THI score (b = 0.07, p = 0.048). Insomnia scores as measured via the Insomnia Severity Index (ISI) were significantly predicted by scores on the depression subscale of the HADS (b = 0.46, p = 0.007). CONCLUSIONS: Since tinnitus annoyance significantly predicts tinnitus handicap, it is important to explore factors associated with annoyance that may be useful in designing appropriate rehabilitative interventions aimed at reducing tinnitus handicap in older people. Future studies should explore whether hyperacusis and insomnia in older people with tinnitus need to be managed in conjunction with treatment for depression

    Identificación del índice de vulnerabilidad territorial a partir de modelos jerárquicos y heurísticos aplicando SOA

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    Auxiliar de InvestigaciónEn el proyecto se realiza el diseño y desarrollo de 4 servicios web implementando los modelos de toma de decisión (AHP, AHP FUZZY, ELECTRE y PROMETHEE), encargados de procesar datos obtenidos en campo en la primera fase del proyecto que se realizó a través de encuestas, formatos de entrevistas, talleres y metodologías de análisis. Los datos se procesaran de acuerdo al modelo de toma de decisión seleccionado, generando como resultado final un indicador de vulnerabilidad territorial.PregradoIngeniero de Sistema

    Evidence for hadronic deconfinement in pˉ\bar{p}-p collisions at 1.8 TeV

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    We have measured deconfined hadronic volumes, 4.4<V<13.04.4 < V < 13.0 fm3^{3}, produced by a one dimensional (1D) expansion. These volumes are directly proportional to the charged particle pseudorapidity densities 6.75<dNc/dη<20.26.75 < dN_{c}/d\eta < 20.2. The hadronization temperature is T=179.5±5T = 179.5 \pm 5 (syst) MeV. Using Bjorken's 1D model,the hadronization energy density is ϵF=1.10±0.26\epsilon_{F} = 1.10 \pm 0.26 (stat) GeV/fm3^{3} corresponding to an excitation of 24.8±6.224.8 \pm 6.2 (stat) quark-gluon degrees of freedom.Comment: 15 pages, 3 figures, 2 table

    Vortex states in 2D superconductor at high magnetic field in a periodic pinning potential

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    The effect of a periodic pinning array on the vortex state in a 2D superconductor at low temperatures is studied within the framework of the Ginzburg-Landau approach. It is shown that attractive interaction of vortex cores to a commensurate pin lattice stabilizes vortex solid phases with long range positional order against violent shear fluctuations. Exploiting a simple analytical method, based on the Landau orbitals description, we derive a rather detailed picture of the low temperatures vortex state phase diagram. It is predicted that for sufficiently clean samples application of an artificial periodic pinning array would enable one to directly detect the intrinsic shear stiffness anisotropy characterizing the ideal vortex lattice.Comment: 8 pages, 5 figure

    Vortex dynamics for two-dimensional XY models

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    Two-dimensional XY models with resistively shunted junction (RSJ) dynamics and time dependent Ginzburg-Landau (TDGL) dynamics are simulated and it is verified that the vortex response is well described by the Minnhagen phenomenology for both types of dynamics. Evidence is presented supporting that the dynamical critical exponent zz in the low-temperature phase is given by the scaling prediction (expressed in terms of the Coulomb gas temperature TCGT^{CG} and the vortex renormalization given by the dielectric constant ϵ~\tilde\epsilon) z=1/ϵ~TCG−2≥2z=1/\tilde{\epsilon}T^{CG}-2\geq 2 both for RSJ and TDGL and that the nonlinear IV exponent a is given by a=z+1 in the low-temperature phase. The results are discussed and compared with the results of other recent papers and the importance of the boundary conditions is emphasized.Comment: 21 pages including 15 figures, final versio

    Anisotropic Scaling in Threshold Critical Dynamics of Driven Directed Lines

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    The dynamical critical behavior of a single directed line driven in a random medium near the depinning threshold is studied both analytically (by renormalization group) and numerically, in the context of a Flux Line in a Type-II superconductor with a bulk current J⃗\vec J. In the absence of transverse fluctuations, the system reduces to recently studied models of interface depinning. In most cases, the presence of transverse fluctuations are found not to influence the critical exponents that describe longitudinal correlations. For a manifold with d=4−ϵd=4-\epsilon internal dimensions, longitudinal fluctuations in an isotropic medium are described by a roughness exponent ζ∥=ϵ/3\zeta_\parallel=\epsilon/3 to all orders in ϵ\epsilon, and a dynamical exponent z∥=2−2ϵ/9+O(ϵ2)z_\parallel=2-2\epsilon/9+O(\epsilon^2). Transverse fluctuations have a distinct and smaller roughness exponent ζ⊥=ζ∥−d/2\zeta_\perp=\zeta_\parallel-d/2 for an isotropic medium. Furthermore, their relaxation is much slower, characterized by a dynamical exponent z⊥=z∥+1/νz_\perp=z_\parallel+1/\nu, where ν=1/(2−ζ∥)\nu=1/(2-\zeta_\parallel) is the correlation length exponent. The predicted exponents agree well with numerical results for a flux line in three dimensions. As in the case of interface depinning models, anisotropy leads to additional universality classes. A nonzero Hall angle, which has no analogue in the interface models, also affects the critical behavior.Comment: 26 pages, 8 Postscript figures packed together with RevTeX 3.0 manuscript using uufiles, uses multicol.sty and epsf.sty, e-mail [email protected] in case of problem
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