1,470 research outputs found

    Distrofia muscular canina ligada ao cromossomo X

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    A distrofia muscular canina ligada ao cromossomo X é a miopatia hereditária mais comum e estudada, caracterizada pela ausência, redução ou alteração na forma de uma proteína citoesquelética, a distrofina. As manifestações clínicas são normalmente observadas entre a sexta e oitava semana de vida, envolvendo primeiramente os membros com piora progressiva do quadro. O diagnóstico é baseado na sintomatologia clínica, exames laboratoriais, eletromiografia e biopsia muscular. É uma afecção desafiadora devido à dificuldade de identificação, diagnóstico adequado e ausência de terapia efetiva. Portanto, objetivou-se com essa revisão esclarecer desde a fisiopatogenia até possíveis tratamentos, possibilitando ao veterinário chegar a um diagnóstico conclusivo, e assim, instituir intervenções que resultem em uma maior expectativa de vida ao paciente, além de detectar os portadores e prevenir a perpetuação dessa condição hereditária

    Physics of Psychophysics: Stevens and Weber-Fechner laws are transfer functions of excitable media

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    Sensory arrays made of coupled excitable elements can improve both their input sensitivity and dynamic range due to collective non-linear wave properties. This mechanism is studied in a neural network of electrically coupled (e.g. via gap junctions) elements subject to a Poisson signal process. The network response interpolates between a Weber-Fechner logarithmic law and a Stevens power law depending on the relative refractory period of the cell. Therefore, these non-linear transformations of the input level could be performed in the sensory periphery simply due to a basic property: the transfer function of excitable media.Comment: 4 pages, 5 figure

    Effects Of 1-mcp Onthe Post-harvest Quality Of The Orange Cv. Pera Stored Under Refrigeration

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    The aim of this work was to analyse the effects of 1-MCP upon the post-harvest quality of the orange cv. Pera stored for 45 days at a temperature of 7 °C. The fruit was divided into four treatments, and then submitted to the application of three concentrations of 1-methylciclopropene (0.1, 0.5 and 1.0μL.L-1) for a period of 12 hours. The fruitwas again then stored at a temperature of 7 °C. The rate of respiration was determined, together withcoloration of the epidermis, SS, TA, ratio, vitamin C, total carotenoids, phenolic compounds, total and reducing sugars, weight loss and juice yield. The data were submitted to analysis of variance (F-Test), and the averages were analysed by regression (P≤0.05). According to the results, it could be seen that higher doses of 1-MCP may have caused chemical stress to the orangesunder evaluation, being responsible for the increasein the rate of respiration. A change in coloration of the epidermis from green to yellow/orange was delayed by the application of 1-MCP; the application of 1-MCP did not cause any alteration to such chemical characteristics as SS, TA, ratio, carotenoids, phenolic compounds or sugars.47462463

    A small universe after all?

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    The cosmic microwave background radiation allows us to measure both the geometry and topology of the universe. It has been argued that the COBE-DMR data already rule out models that are multiply connected on scales smaller than the particle horizon. Here we show the opposite is true: compact (small) hyperbolic universes are favoured over their infinite counterparts. For a density parameter of Omega_o=0.3, the compact models are a better fit to COBE-DMR (relative likelihood ~20) and the large-scale structure data (sigma_8 increases by ~25%).Comment: 4 pages, RevTeX, 7 Figure

    Using smart meters to estimate low voltage losses

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    Losses on low voltage networks are often substantial. For example, in the UK they have been estimated as being 4% of the energy supplied by low voltage networks. However, the breakdown of the losses to individual conductors and their split over time are poorly understood as generally only the peak demands and average loads over several months have been recorded. The introduction of domestic smart meters has the potential to change this. How domestic smart meter readings can be used to estimate the actual losses is analysed. In particular, the accuracy of using 30 minute readings compared with 1 minute readings, and how this accuracy could be improved, were investigated. This was achieved by assigning the data recorded by 100 smart meters with a time resolution of 1 minute to three test networks. Smart meter data from three sources were used in the investigation. It was found that 30 minute resolution data underestimated the losses by between 9% and 24%. By fitting an appropriate model to the data, it was possible to reduce the inaccuracy by approximately 50%. Having a smart meter time resolution of 10 minutes rather than 30 gave little improvement to the accuracy

    Spanning forests and the q-state Potts model in the limit q \to 0

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    We study the q-state Potts model with nearest-neighbor coupling v=e^{\beta J}-1 in the limit q,v \to 0 with the ratio w = v/q held fixed. Combinatorially, this limit gives rise to the generating polynomial of spanning forests; physically, it provides information about the Potts-model phase diagram in the neighborhood of (q,v) = (0,0). We have studied this model on the square and triangular lattices, using a transfer-matrix approach at both real and complex values of w. For both lattices, we have computed the symbolic transfer matrices for cylindrical strips of widths 2 \le L \le 10, as well as the limiting curves of partition-function zeros in the complex w-plane. For real w, we find two distinct phases separated by a transition point w=w_0, where w_0 = -1/4 (resp. w_0 = -0.1753 \pm 0.0002) for the square (resp. triangular) lattice. For w > w_0 we find a non-critical disordered phase, while for w < w_0 our results are compatible with a massless Berker-Kadanoff phase with conformal charge c = -2 and leading thermal scaling dimension x_{T,1} = 2 (marginal operator). At w = w_0 we find a "first-order critical point": the first derivative of the free energy is discontinuous at w_0, while the correlation length diverges as w \downarrow w_0 (and is infinite at w = w_0). The critical behavior at w = w_0 seems to be the same for both lattices and it differs from that of the Berker-Kadanoff phase: our results suggest that the conformal charge is c = -1, the leading thermal scaling dimension is x_{T,1} = 0, and the critical exponents are \nu = 1/d = 1/2 and \alpha = 1.Comment: 131 pages (LaTeX2e). Includes tex file, three sty files, and 65 Postscript figures. Also included are Mathematica files forests_sq_2-9P.m and forests_tri_2-9P.m. Final journal versio
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