5,853 research outputs found

    Discrete Symmetries of Off-Shell Electromagnetism

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    We discuss the discrete symmetries of the Stueckelberg-Schrodinger relativistic quantum theory and its associated 5D local gauge theory, a dynamical description of particle/antiparticle interactions, with monotonically increasing Poincare-invariant parameter. In this framework, worldlines are traced out through the parameterized evolution of spacetime events, advancing or retreating with respect to the laboratory clock, with negative energy trajectories appearing as antiparticles when the observer describes the evolution using the laboratory clock. The associated gauge theory describes local interactions between events (correlated by the invariant parameter) mediated by five off-shell gauge fields. These gauge fields are shown to transform tensorially under under space and time reflections, unlike the standard Maxwell fields, and the interacting quantum theory therefore remains manifestly Lorentz covariant. Charge conjugation symmetry in the quantum theory is achieved by simultaneous reflection of the sense of evolution and the fifth scalar field. Applying this procedure to the classical gauge theory leads to a purely classical manifestation of charge conjugation, placing the CPT symmetries on the same footing in the classical and quantum domains. In the resulting picture, interactions do not distinguish between particle and antiparticle trajectories -- charge conjugation merely describes the interpretation of observed negative energy trajectories according to the laboratory clock.Comment: 26 page

    Non-Gaussianity detections in the Bianchi VIIh corrected WMAP 1-year data made with directional spherical wavelets

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    Many of the current anomalies reported in the Wilkinson Microwave Anisotropy Probe (WMAP) 1-year data disappear after `correcting' for the best-fit embedded Bianchi type VII_h component (Jaffe et al. 2005), albeit assuming no dark energy component. We investigate the effect of this Bianchi correction on the detections of non-Gaussianity in the WMAP data that we previously made using directional spherical wavelets (McEwen et al. 2005a). As previously discovered by Jaffe et al. (2005), the deviations from Gaussianity in the kurtosis of spherical Mexican hat wavelet coefficients are eliminated once the data is corrected for the Bianchi component. This is due to the reduction of the cold spot at Galactic coordinates (l,b)=(209^\circ,-57\circ), which Cruz et al. (2005) claim to be the source of non-Gaussianity introduced in the kurtosis. Our previous detections of non-Gaussianity observed in the skewness of spherical wavelet coefficients are not reduced by the Bianchi correction. Indeed, the most significant detection of non-Gaussianity made with the spherical real Morlet wavelet at a significant level of 98.4% remains (using a very conservative method to estimate the significance). We make our code to simulate Bianchi induced temperature fluctuations publicly available.Comment: 11 pages, 8 figures, replaced to match version accepted by MNRA

    Child Well-being in the Pacific Rim

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    This study extends previous efforts to compare the well-being of children using multi-dimensional indicators derived from sample survey and administrative series to thirteen countries in the Pacific Rim. The framework for the analysis of child well-being is to organise 46 indicators into 21 components and organise the components into 6 domains: material situation, health, education, subjective well-being, living environment, as well as risk and safety. Overall, Japan, Singapore and Taiwan have the highest child well-being and Thailand, Indonesia and the Philippines the lowest. However, there are substantial variations between the domains. Japan and Korea perform best on the material well-being of children and also do well on health and education but they have the lowest subjective well-being among their children by some margin. There is a relationship between child well-being and GDP per capita but children in China have higher well-being than you would expect given their GDP and children in Australia have lower well-being. The analysis is constrained by missing data particularly that the Health Behaviour of School-Aged Children Survey is not undertaken in any of these countries

    Experimental and computational characterization of a modified GEC cell for dusty plasma experiments

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    A self-consistent fluid model developed for simulations of micro- gravity dusty plasma experiments has for the first time been used to model asymmetric dusty plasma experiments in a modified GEC reference cell with gravity. The numerical results are directly compared with experimental data and the experimentally determined dependence of global discharge parameters on the applied driving potential and neutral gas pressure is found to be well matched by the model. The local profiles important for dust particle transport are studied and compared with experimentally determined profiles. The radial forces in the midplane are presented for the different discharge settings. The differences between the results obtained in the modified GEC cell and the results first reported for the original GEC reference cell are pointed out

    Non-deterministic density classification with diffusive probabilistic cellular automata

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    We present a probabilistic cellular automaton (CA) with two absorbing states which performs classification of binary strings in a non-deterministic sense. In a system evolving under this CA rule, empty sites become occupied with a probability proportional to the number of occupied sites in the neighborhood, while occupied sites become empty with a probability proportional to the number of empty sites in the neighborhood. The probability that all sites become eventually occupied is equal to the density of occupied sites in the initial string.Comment: 4 pages, 4 figure

    Follow-up study of sensory-motor polyneuropathy in Type 1 (insulin-dependent) diabetic subjects after simultaneous pancreas and kidney transplantation and after graft rejection

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    The influence of successful simultaneous pancreas and kidney transplantation on peripheral polyneuropathy was investigated in 53 patients for a mean observation period of 40.3 months. Seventeen patients were followed-up for more than 3 years. Symptoms and signs were assessed every 6 months using a standard questionnaire, neurological examination and measurement of sensory and motor nerve conduction velocities. While symptoms of polyneuropathy improved (pain, paraesthesia, cramps, restless-legs) and nerve conduction velocity increased, there was no change of clinical signs (sensation, muscle-force, tendon-reflexes). Following kidney-graft-rejection there was a slight decrease of nerve conduction verlocity during the first year, which was not statistically significant. Following pancreas-graft rejection there was no change of nerve conduction velocity during the first year. Comparing the maximum nerve conduction velocity of the patients with pancreas-graft-rejection to the nerve conduction velocities of these patients at the end of the study, there was a statistically significant decrease of 6.5 m/s. In conclusion, we believe that strict normalization of glucose metabolism alters the progressive course of diabetic polyneuropathy. It may be stabilized or partly reversed after successful grafting even in long-term diabetic patients

    The effect of thermophoresis on the discharge parameters in complex plasma experiments

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    Thermophoresis is a tool often applied in complex plasma experiments. One of the usual stated benefits over other experimental tools is that changes induced by thermophoresis neither directly depend on, nor directly influence, the plasma parameters. From electronic data, plasma emission profiles in the sheath, and Langmuir probe data in the plasma bulk, we conclude that this assumption does not hold. An important effect on the levitation of dust particles in argon plasma is observed as well. The reason behind the changes in plasma parameters seems to be the change in neutral atom density accompanying the increased gas temperature while running at constant pressure.Comment: 14 pages, 12 figure
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