4,787 research outputs found

    Are Changing Demographics Fostering a New Role for Farmers?

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    Skill sets, profitability, management skills, ordered probit, Agribusiness,

    PAN AIR analysis of the NASA/MCAIR 279-3: An advanced supersonic V/STOL fighter/attack aircraft

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    PAN AIR is a computer program for predicting subsonic or supersonic linear potential flow about arbitrary configurations. The program was applied to a highly complex single-engine-cruise V/STOL fighter/attack aircraft. Complexities include a close-coupled canard/wing, large inlets, and four exhaust nozzles mounted directly under the wing and against the fuselage. Modeling uncertainties involving canard wake location and flow-through approximation through the inlet and the exhaust nozzles were investigated. The recently added streamline capability of the program was utilized to evaluate visually the predicted flow over the model. PAN AIR results for Mach numbers of 0.6, 0.9, and angles of attack of 0, 5, and 10 deg. were compared with data obtained in the Ames 11- by 11-Foot Transonic Wind tunnel, at a Reynolds number of 3.69 x 10 to the 6th power based on c bar

    Low-noise kinetic inductance traveling-wave amplifier using three-wave mixing

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    We have fabricated a wide-bandwidth, high dynamic range, low-noise cryogenic amplifier based on a superconducting kinetic inductance traveling-wave device. The device was made from NbTiN and consisted of a long, coplanar waveguide on a silicon chip. By adding a DC current and an RF pump tone we are able to generate parametric amplification using three-wave mixing. The devices exhibit gain of more than 15 dB across an instantaneous bandwidth from 4 to 8 GHz. The total usable gain bandwidth, including both sides of the signal-idler gain region, is more than 6 GHz. The noise referred to the input of the devices approaches the quantum limit, with less than 1 photon excess noise. Compared to similarly constructed four-wave mixing amplifiers, these devices operate with the RF pump at \sim20 dB lower power and at frequencies far from the signal. This will permit easier integration into large scale qubit and detector applications

    Off-farm Income and Investments in Farm Assets: A Double Hurdle Approach

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    The farm household structure is a complex set of inter-relationships between and among a variety of internal and external factors involving consumption, investment, and income-earning activities. In this paper we use ARMS data to explore the contribution of off-farm income to the viability of the farm business. We focus on the link between off-farm income and farm investment and whether off-farm income drives on-farm investment. The results indicate the importance of farm characteristics such as type, size, and location on the probability of investment but lead us to reject the hypothesis that off farm income is driving farm investment. Further research will be needed to further unweave some of the complex relationships involved in the farm household structure. Keywords: Farm investments, off-farm income, double hurdleOff-farm income, farm investment, double hurdle, Agricultural Finance, Financial Economics, D1, J2, Q12,

    When age-progressed images are unreliable: The roles of external features and age range

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    When children go missing for many years, investigators commission age-progressed images from forensic artists to depict an updated appearance. These images have anecdotal success, and systematic research has found they lead to accurate recognition rates comparable to outdated photos. The present study examines the reliability of age progressions of the same individuals created by different artists. Eight artists first generated age progressions of eight targets across three age ranges. Eighty-five participants then evaluated the similarity of these images against other images depicting the same targets progressed at the same age ranges, viewing either whole faces or faces with external features concealed. Similarities were highest over shorter age ranges and when external features were concealed. Implications drawn from theory and application are discussed

    Determinants of Farm Household Income Diversification in the United States: Evidence from Farm-Level Data

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    This study examines the determinants of income diversification of farm households in the United States. Farm households allocate their time between farm and off-farm activities to help stabilized household income (consumption). What characterizes those households who engage in off-farm activities? Is there any pattern over time? Using 1999, 2003 and 2007 farm-level data from the USDA’s Agricultural Resource Management Survey (ARMS), this study estimates intensity of off-farm income (or income diversification). The results show that older operators, full owners, and small farms have higher intensity of off-farm income in total household income. In contrast, dairy farms, vertically coordinated farms and farms located in the Southern and Pacific regions have lower intensity of off-farm income. In other words, household incomes of these farms are less likely to be diversified.Tobit, income diversification, vertical integration, tenure, farm households, Agricultural Finance, Consumer/Household Economics, D1, J2, Q12,

    A High Throughput Workflow Environment for Cosmological Simulations

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    The next generation of wide-area sky surveys offer the power to place extremely precise constraints on cosmological parameters and to test the source of cosmic acceleration. These observational programs will employ multiple techniques based on a variety of statistical signatures of galaxies and large-scale structure. These techniques have sources of systematic error that need to be understood at the percent-level in order to fully leverage the power of next-generation catalogs. Simulations of large-scale structure provide the means to characterize these uncertainties. We are using XSEDE resources to produce multiple synthetic sky surveys of galaxies and large-scale structure in support of science analysis for the Dark Energy Survey. In order to scale up our production to the level of fifty 10^10-particle simulations, we are working to embed production control within the Apache Airavata workflow environment. We explain our methods and report how the workflow has reduced production time by 40% compared to manual management.Comment: 8 pages, 5 figures. V2 corrects an error in figure
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