10,557 research outputs found

    The Muscadine Experience: Adding Value to Enhance Profits

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    The University of Arkansas Division of Agriculture received a grant from the National Research Initiative (NRI), CSREES USDA. The purpose was to help small- and medium-sized farmers and entrepreneurs enhance the viability of their farms through the establishment of vineyards, on-farm wineries, and production of value-added products from grapes and grape by-products. This publication looks at efforts by the UA Grape and Wine Research Program to enhance the profitability of muscadine grapes. Included are discussions of research designed to develop the market potential of muscadines as fresh fruit and as value-added products such as juice, wine, sweet spreads, vinegar, and dried products. The skin and seeds of muscadines have traditionally been considered waste; however, recent research has shown that they contain nutraceutical components. Reports are included of research to quantify these nutraceuticals and to develop products containing them

    The Muscadine Experience: Adding Value to Enhance Profits

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    The University of Arkansas Division of Agriculture received a grant from the USDA’s Initiative for Future Agriculture and Food Systems (IFAFS) program. The purpose was to help small- and medium-sized farmers and entrepreneurs become more profitable and therefore add stability to the family farm. One approach to doing this is to investigate opportunities to enhance profits by adding value to traditional raw products

    Integrability of the Minimal Strain Equations for the Lapse and Shift in 3+1 Numerical Relativity

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    Brady, Creighton and Thorne have argued that, in numerical relativity simulations of the inspiral of binary black holes, if one uses lapse and shift functions satisfying the ``minimal strain equations'' (MSE), then the coordinates might be kept co-rotating, the metric components would then evolve on the very slow inspiral timescale, and the computational demands would thus be far smaller than for more conventional slicing choices. In this paper, we derive simple, testable criteria for the MSE to be strongly elliptic, thereby guaranteeing the existence and uniqueness of the solution to the Dirichlet boundary value problem. We show that these criteria are satisfied in a test-bed metric for inspiraling binaries, and we argue that they should be satisfied quite generally for inspiraling binaries. If the local existence and uniqueness that we have proved holds globally, then, for appropriate boundary values, the solution of the MSE exhibited by Brady et. al. (which tracks the inspiral and keeps the metric evolving slowly) will be the unique solution and thus should be reproduced by (sufficiently accurate and stable) numerical integrations.Comment: 6 pages; RevTeX; submitted to Phys. Rev. D15. Technical issue of the uniqueness of the solution to the Dirichlet problem clarified. New subsection on the nature of the boundary dat

    Stability of degenerate Cauchy horizons in black hole spacetimes

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    In the multihorizon black hole spacetimes, it is possible that there are degenerate Cauchy horizons with vanishing surface gravities. We investigate the stability of the degenerate Cauchy horizon in black hole spacetimes. Despite the asymptotic behavior of spacetimes (flat, anti-de Sitter, or de Sitter), we find that the Cauchy horizon is stable against the classical perturbations, but unstable quantum mechanically.Comment: Revtex, 4 pages, no figures, references adde

    Production and Handling Practices for Safe Produce

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    The University of Arkansas Division of Agriculture received a grant from the USDA’s Initiative for Future Agriculture and Food Systems program to help small- and medium-sized farms become more profitable and to therefore add stability to the family farm. One approach to doing this is to help farmers growing produce reduce or eliminate safety hazards which may be associated with their products

    Quantum Effects in Black Hole Interiors

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    The Weyl curvature inside a black hole formed in a generic collapse grows, classically without bound, near to the inner horizon, due to partial absorption and blueshifting of the radiative tail of the collapse. Using a spherical model, we examine how this growth is modified by quantum effects of conformally coupled massless fields.Comment: 13 pages, 1 figure (not included), RevTe

    Good Agricultural and Handling Practices for Grapes and Other Fresh Produce

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    In recent years consumption of fresh fruits and vegetables has increased dramatically. This trend has increased the amount of produce being purchased at farmer’s markets, road-side stands, and neighborhood markets since consumers say they feel that the direct contact with growers at these markets makes them better able to assess the quality and safety of the produce. This buying trend has opened new markets to small- and medium-sized farms, which sell at these local outlets

    The late-time singularity inside non-spherical black holes

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    It was long believed that the singularity inside a realistic, rotating black hole must be spacelike. However, studies of the internal geometry of black holes indicate a more complicated structure is typical. While it seems likely that an observer falling into a black hole with the collapsing star encounters a crushing spacelike singularity, an observer falling in at late times generally reaches a null singularity which is vastly different in character to the standard Belinsky, Khalatnikov and Lifschitz (BKL) spacelike singularity. In the spirit of the classic work of BKL we present an asymptotic analysis of the null singularity inside a realistic black hole. Motivated by current understanding of spherical models, we argue that the Einstein equations reduce to a simple form in the neighborhood of the null singularity. The main results arising from this approach are demonstrated using an almost plane symmetric model. The analysis shows that the null singularity results from the blueshift of the late-time gravitational wave tail; the amplitude of these gravitational waves is taken to decay as an inverse power of advanced time as suggested by perturbation theory. The divergence of the Weyl curvature at the null singularity is dominated by the propagating modes of the gravitational field. The null singularity is weak in the sense that tidal distortion remains bounded along timelike geodesics crossing the Cauchy horizon. These results are in agreement with previous analyses of black hole interiors. We briefly discuss some outstanding problems which must be resolved before the picture of the generic black hole interior is complete.Comment: 16 pages, RevTeX, 3 figures included using psfi

    A nonlinear detection algorithm for periodic signals in gravitational wave detectors

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    We present an algorithm for the detection of periodic sources of gravitational waves with interferometric detectors that is based on a special symmetry of the problem: the contributions to the phase modulation of the signal from the earth rotation are exactly equal and opposite at any two instants of time separated by half a sidereal day; the corresponding is true for the contributions from the earth orbital motion for half a sidereal year, assuming a circular orbit. The addition of phases through multiplications of the shifted time series gives a demodulated signal; specific attention is given to the reduction of noise mixing resulting from these multiplications. We discuss the statistics of this algorithm for all-sky searches (which include a parameterization of the source spin-down), in particular its optimal sensitivity as a function of required computational power. Two specific examples of all-sky searches (broad-band and narrow-band) are explored numerically, and their performances are compared with the stack-slide technique (P. R. Brady, T. Creighton, Phys. Rev. D, 61, 082001).Comment: 9 pages, 3 figures, to appear in Phys. Rev.
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