15,051 research outputs found

    MANURE HANDLING COSTS AND THE COMPETITIVENESS OF PORK PRODUCTION

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    Simulations of possible regulation-related manure handling costs are compared to base scenario costs for the three main regions and phases of modern hog production over widely varying scale levels. The base scenario confirms previous research suggesting that in Iowa net benefits occur at small scale levels from injecting slurry stored in an outside earthern basin for corn production using a phosphorus standard. Increased transportation costs result in Iowa costs surpassing costs in Utah at higher scale levels, while costs in North Carolina are highest at all scale levels. Requiring systems to be lined and covered in Iowa and North Carolina results in proportionately greater increased costs per head in North Carolina. Adding the requirement that manure be applied according to a phosphorus standard increases costs proportionately more in Iowa at larger scale levels, but not at all at the smallest scale, and costs in Iowa surpass those in North Carolina at the largest scale. The results of all scenarios underscore the advantages enjoyed by Utah in manure handling because scales of operation there are among the largest.Livestock Production/Industries,

    WELFARE IMPLICATIONS OF THE WOOL ACT

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    A model of the U.S. sheep industry is estimated and simulated to determine the impact of the wool incentive program on actors in U.S. sheep product markets. The simulation analysis indicates that U.S. sheep producers and lamb and wool consumers are the programÂ’s gainers while lamb and wool exporters and taxpayers are its losers. Net societal losses averaged $26.4 million per year during the 1980-85 period, considering U.S. as well as exporter interests. This loss is about 2.5% of average U.S. consumer expenditures on lamb and wool over the period.Agricultural and Food Policy, Livestock Production/Industries,

    Slave finite element for non-linear analysis of engine structures. Volume 2: Programmer's manual and user's manual

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    The programming aspects of SFENES are described in the User's Manual. The information presented is provided for the installation programmer. It is sufficient to fully describe the general program logic and required peripheral storage. All element generated data is stored externally to reduce required memory allocation. A separate section is devoted to the description of these files thereby permitting the optimization of Input/Output (I/O) time through efficient buffer descriptions. Individual subroutine descriptions are presented along with the complete Fortran source listings. A short description of the major control, computation, and I/O phases is included to aid in obtaining an overall familiarity with the program's components. Finally, a discussion of the suggested overlay structure which allows the program to execute with a reasonable amount of memory allocation is presented

    REVEALED COMPARATIVE ADVANTAGE AND THE MEASUREMENT OF INTERNATIONAL COMPETITIVENESS FOR AGRICULTURAL COMMODITIES: AN EMPIRICAL ANALYSIS OF WOOL EXPORTERS

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    Trade liberalization and laissez-faire economics are altering the structure of agricultural production and trade. The principle of comparative advantage, a classic tenet of economics, is a useful tool for understanding the future of world agriculture. This study employs a "Revealed Comparative Advantage" approach to investigate patterns of comparative advantage among six major wool exporting countries.International Relations/Trade,

    Measurements of Surface Diffusivity and Coarsening During Pulsed Laser Deposition

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    Pulsed Laser Deposition (PLD) of homoepitaxial SrTiO3 was studied with in-situ x-ray specular reflectivity and surface diffuse x-ray scattering. Unlike prior reflectivity-based studies, these measurements access both the time- and the length-scales of the evolution of the surface morphology during growth. In particular, we show that this technique allows direct measurements of the diffusivity for both inter- and intra-layer transport. Our results explicitly limit the possible role of island break-up, demonstrate the key roles played by nucleation and coarsening in PLD, and place an upper bound on the Ehrlich-Schwoebel (ES) barrier for downhill diffusion

    Travelling waves in wound healing

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    We illustrate the role of travelling waves in wound healing by considering three different cases. Firstly, we review a model for surface wound healing in the cornea and focus on the speed of healing as a function of the application of growth factors. Secondly, we present a model for scar tissue formation in deep wounds and focus on the role of key chemicals in determining the quality of healing. Thirdly, we propose a model for excessive healing disorders and investigate how abnormal healing may be controlled

    Synthetic 26Al emission from galactic-scale superbubble simulations

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    © 2019 The Author(s).Emission from the radioactive trace element 26Al has been observed throughout the Milky Way with the COMPTEL and INTEGRAL satellites. In particular the Doppler shifts measured with INTEGRAL connect 26Al with superbubbles, which may guide 26Al flows off spiral arms in the direction of Galactic rotation. In order to test this paradigm, we have performed galaxy-scale simulations of superbubbles with 26Al injection in a Milky Way-type galaxy. We produce all-sky synthetic γ\gamma-ray emission maps of the simulated galaxies. We find that the 1809keV emission from the radioactive decay of 26Al is highly variable with time and the observer's position. This allows us to estimate an additional systematic variability of 0.2dex for a star formation rate derived from 26Al for different times and measurement locations in Milky Way-type galaxies. High-latitude morphological features indicate nearby emission with correspondingly high integrated gamma-ray intensities. We demonstrate that the 26Al scale height from our simulated galaxies depends on the assumed halo gas density. We present the first synthetic 1809keV longitude-velocity diagrams from 3D hydrodynamic simulations. The line-of-sight velocities for 26Al can be significantly different from the line-of-sight velocities associated with the cold gas. Over time, 26Al velocities consistent with the INTEGRAL observations, within uncertainties, appear at any given longitude, broadly supporting previous suggestions that 26Al injected into expanding superbubbles by massive stars may be responsible for the high velocities found in the INTEGRAL observations. We discuss the effect of systematically varying the location of the superbubbles relative to the spiral arms.Peer reviewedFinal Accepted Versio
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