34,123 research outputs found

    An orthogonal oriented quadrature hexagonal image pyramid

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    An image pyramid has been developed with basis functions that are orthogonal, self-similar, and localized in space, spatial frequency, orientation, and phase. The pyramid operates on a hexagonal sample lattice. The set of seven basis functions consist of three even high-pass kernels, three odd high-pass kernels, and one low-pass kernel. The three even kernels are identified when rotated by 60 or 120 deg, and likewise for the odd. The seven basis functions occupy a point and a hexagon of six nearest neighbors on a hexagonal sample lattice. At the lowest level of the pyramid, the input lattice is the image sample lattice. At each higher level, the input lattice is provided by the low-pass coefficients computed at the previous level. At each level, the output is subsampled in such a way as to yield a new hexagonal lattice with a spacing sq rt 7 larger than the previous level, so that the number of coefficients is reduced by a factor of 7 at each level. The relationship between this image code and the processing architecture of the primate visual cortex is discussed

    THE GENERALIZED COMPOSITE COMMODITY THEOREM AND FOOD DEMAND ESTIMATION

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    This paper reports tests of aggregation over consumer food products and estimates of aggregate food demand elasticities. Evidence that food demand variables follow unit root processes leads us to build on and simplify tests of the Generalized Composite Commodity Theorem found in the literature. We compute food demand elasticities using cointegration applied to a convenient but nonlinear functional form. Estimates are based on consumer reported expenditure data rather than commercial disappearance data.Demand and Price Analysis,

    Experimental Studies for the Detection of Protein in Trace Amounts Quarterly Status Report, 1 Mar. - 31 May 1965

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    Methods for separating inorganic compounds from organic materials in investigation of trace proteins in soil

    Lattice Gas Dynamics; Application to Driven Vortices in Two Dimensional Superconductors

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    A continuous time Monte Carlo lattice gas dynamics is developed to model driven steady states of vortices in two dimensional superconducting networks. Dramatic differences are found when compared to a simpler Metropolis dynamics. Subtle finite size effects are found at low temperature, with a moving smectic that becomes unstable to an anisotropic liquid on sufficiently large length scales.Comment: 5 pages, 4 figure

    Search for Neutrinoless Double-Beta Decay with the Upgraded EXO-200 Detector

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    Results from a search for neutrinoless double-beta decay ( 0νββ) of ^(136)Xe are presented using the first year of data taken with the upgraded EXO-200 detector. Relative to previous searches by EXO-200, the energy resolution of the detector has been improved to σ/E = 1.23%, the electric field in the drift region has been raised by 50%, and a system to suppress radon in the volume between the cryostat and lead shielding has been implemented. In addition, analysis techniques that improve topological discrimination between 0νββ and background events have been developed. Incorporating these hardware and analysis improvements, the median 90% confidence level 0νββ half-life sensitivity after combining with the full data set acquired before the upgrade has increased twofold to 3.7 × 10^(25) yr. No statistically significant evidence for 0νββ is observed, leading to a lower limit on the 0νββ half-life of 1.8 × 10^(25) yr at the 90% confidence level

    Searches for double beta decay of ^(134)Xe with EXO-200

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    Searches for double beta decay of ^(134)Xe were performed with EXO-200, a single-phase liquid xenon detector designed to search for neutrinoless double beta decay of ^(136)Xe. Using an exposure of 29.6  kg⋅yr, the lower limits of T^(2νββ_+(1/2) > 8.7×10^(20)  yr and T^(0νββ)_(1/2) > 1.1×10^(23)  yr at 90% confidence level were derived, with corresponding half-life sensitivities of 1.2×10^(21)  yr and 1.9×10^(23)  yr. These limits exceed those in the literature for ^(134)Xe, improving by factors of nearly 105 and 2 for the two antineutrino and neutrinoless modes, respectively

    Batalin-Vilkovisky Integrals in Finite Dimensions

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    The Batalin-Vilkovisky method (BV) is the most powerful method to analyze functional integrals with (infinite-dimensional) gauge symmetries presently known. It has been invented to fix gauges associated with symmetries that do not close off-shell. Homological Perturbation Theory is introduced and used to develop the integration theory behind BV and to describe the BV quantization of a Lagrangian system with symmetries. Localization (illustrated in terms of Duistermaat-Heckman localization) as well as anomalous symmetries are discussed in the framework of BV.Comment: 35 page
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