32,507 research outputs found

    Staggered Heavy Baryon Chiral Perturbation Theory

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    Although taste violations significantly affect the results of staggered calculations of pseudoscalar and heavy-light mesonic quantities, those entering staggered calculations of baryonic quantities have not been quantified. Here I develop staggered chiral perturbation theory in the light-quark baryon sector by mapping the Symanzik action into heavy baryon chiral perturbation theory. For 2+1 dynamical quark flavors, the masses of flavor-symmetric nucleons are calculated to third order in partially quenched and fully dynamical staggered chiral perturbation theory. To this order the expansion includes the leading chiral logarithms, which come from loops with virtual decuplet-like states, as well as terms the order of the cubed pion mass, which come from loops with virtual octet-like states. Taste violations enter through the meson propagators in loops and tree-level terms the order of the squared lattice spacing. The pattern of taste symmetry breaking and the resulting degeneracies and mixings are discussed in detail. The resulting chiral forms are appropriate to lattice results obtained with operators already in use and could be used to study the restoration of taste symmetry in the continuum limit. I assume that the fourth root of the fermion determinant can be incorporated in staggered chiral perturbation theory using the replica method.Comment: 54 pages; v2: corrected discussion in Sec. III.C, conclusions unchange

    Cryogenic flux-concentrator

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    Flux concentrator has high primary to secondary coupling efficiency enabling it to produce high magnetic fields. The device provides versatility in pulse duration, magnetic field strengths and power sources

    Requirements for multidisciplinary design of aerospace vehicles on high performance computers

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    The design of aerospace vehicles is becoming increasingly complex as the various contributing disciplines and physical components become more tightly coupled. This coupling leads to computational problems that will be tractable only if significant advances in high performance computing systems are made. Some of the modeling, algorithmic and software requirements generated by the design problem are discussed

    Perceptually smooth timbral guides by state-space analysis of phase-vocoder parameters

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    Sculptor is a phase-vocoder-based package of programs that allows users to explore timbral manipulation of sound in real time. It is the product of a research program seeking ultimately to perform gestural capture by analysis of the sound a performer makes using a conventional instrument. Since the phase-vocoder output is of high dimensionality — typically more than 1,000 channels per analysis frame—mapping phase-vocoder output to appropriate input parameters for a synthesizer is only feasible in theory

    A holistic multimodal approach to the non-invasive analysis of watercolour paintings

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    A holistic approach using non-invasive multimodal imaging and spectroscopic techniques to study the materials (pigments, drawing materials and paper) and painting techniques of watercolour paintings is presented. The non-invasive imaging and spectroscopic techniques include VIS-NIR reflectance spectroscopy and multispectral imaging, micro-Raman spectroscopy, X-ray fluorescence spectroscopy (XRF) and optical coherence tomography (OCT). The three spectroscopic techniques complement each other in pigment identification. Multispectral imaging (near infrared bands), OCT and micro-Raman complement each other in the visualisation and identification of the drawing material. OCT probes the microstructure and light scattering properties of the substrate while XRF detects the elemental composition that indicates the sizing methods and the filler content . The multiple techniques were applied in a study of forty six 19th century Chinese export watercolours from the Victoria & Albert Museum (V&A) and the Royal Horticultural Society (RHS) to examine to what extent the non-invasive analysis techniques employed complement each other and how much useful information about the paintings can be extracted to address art conservation and history questions

    It\u27s all in the lens: Differences in views on obesity prevention between advocates and policy makers

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    Background: Intervention strategies to reduce obesity include policy and environmental changes that are designed to provide opportunities, support, and cues to help people develop healthier behaviors. Policy changes at the state level are one way to influence access, social norms, and opportunities for better nutrition and increased physical activity among the population. Methods: Ten states were selected for a broad variance in obesity rates and number of enacted obesity prevention policies during the years of 2006–2009. Within the selected states, a purely qualitative study of attitudes of childhood obesity policy using semistructured telephone interviews was conducted. Interviews were conducted with state policy makers who serve on public health committees. A set of six states that had more than eight childhood obesity policies enacted were selected for subsequent qualitative interviews with a convenience sample of well-established advocates. Results: Policy makers in states where there was more childhood obesity policy action believed in the evidence behind obesity policy proposals. Policy makers also varied in the perception of obesity as a constituent priority. The major differences between advocates and policy makers included a disconnect in information dissemination, opposition, and effectiveness of these policies. Conclusions: The findings from this study show differences in perceptions among policy makers in states with a greater number of obesity prevention bills enacted. There are differences among policy makers and advocates regarding the role and effectiveness of state policy on obesity prevention. This presents an opportunity for researchers and practitioners to improve communication and translation of evidence to policy makers, particularly in states with low legislation

    Plan dairy chores

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