1,349 research outputs found

    DISENTANGLING THE PRODUCTION AND EXPORT CONSEQUENCES OF DIRECT FARM INCOME PAYMENTS

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    This paper formalizes the production and export consequences of direct farm payments. Taxpayer financed direct payments distort exit and production incentives, while consumer financed subsidies also imply that the risks of domestic and export production differ. Welfare decompostion and empirical calibration illustrate the potential for import barriers to cross-subsidize exports.Agricultural and Food Policy, International Relations/Trade,

    The effects of policy expectations on crop supply, with an application to base updating

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    We develop a dynamic model to assess the effects of policy expectations on crop supply and illustrate the approach with estimates of the effects of base updating in U.S. crop programs. For corn and soybeans in the Corn Belt, the effect of base updating is relatively small because relevant crop alternatives are subject to similar policies and the alternatives are substitutes in production. Increasing acreage of one program crop to capture future payments from base updating reduces future payments from the alternative crop. We also use our model to assess the effect of base updating on acreage response to prices

    Can biofuel policies reduce uncertainty and increase agricultural yields through stimulating investments?

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    As history shows, the yield gap (the difference between actual and achievable yields) will not necessarily close automatically. Investments in agricultural technologies may be key. Price volatility is fundamental to investment. Price volatility has increased in agriculture in the past decade, leading to higher risks for potential investments. Some of these increased risks may be offset by the certainty offered by credible policies. The US experience indicates that ethanol policy may contribute to yield increases. Analysis suggests that corn use by ethanol plants in the USA may explain a significant part of the observed yield increase. A theoretical framework, centered on downside price-stabilization effects, is offered here, supported by some US, EU, and Hungarian empirical evidence. The research presented explores whether new ethanol plants resulting from effective biofuel policies could serve as a market mechanism to stimulate investments in farming technologies, triggering increased productivity. A survey of local stakeholders of an ethanol plant in Hungary, the only large-scale biofuel investment triggered in Europe by the EUā€™s flagship bioenergy policy (the Renewable Energy Directive) suggests that relevant investments may have been stimulated. Over half of the respondent farmers said that the presence of the ethanol plant had stimulated investments in productivity. It is proposed that ethanol or biofuel policies may be effective in closing the yield gap, in effect resulting in additional biomass production and advancing the bioeconomy. With effective cross-sectoral policies, more biomass for food, feed, bio-based materials and / or bioenergy purposes can be produced

    Failed theories of superconductivity

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    Almost half a century passed between the discovery of superconductivity by Kamerlingh Onnes and the theoretical explanation of the phenomenon by Bardeen, Cooper and Schrieffer. During the intervening years the brightest minds in theoretical physics tried and failed to develop a microscopic understanding of the effect. A summary of some of those unsuccessful attempts to understand superconductivity not only demonstrates the extraordinary achievement made by formulating the BCS theory, but also illustrates that mistakes are a natural and healthy part of the scientific discourse, and that inapplicable, even incorrect theories can turn out to be interesting and inspiring.Comment: 14 pages, 3 figures (typos fixed), to appear in: Bardeen Cooper and Schrieffer: 50 YEARS, edited by Leon N Cooper and Dmitri Feldma

    Comparison among Various Expressions of Complex Admittance for Quantum System in Contact with Heat Reservoir

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    Relation among various expressions of the complex admittance for quantum systems in contact with heat reservoir is studied. Exact expressions of the complex admittance are derived in various types of formulations of equations of motion under contact with heat reservoir. Namely, the complex admittance is studied in the relaxation method and the external-field method. In the former method, the admittance is calculated using the Kubo formula for quantum systems in contact with heat reservoir in no external driving fields, while in the latter method the admittance is directly calculated from equations of motion with external driving terms. In each method, two types of equation of motions are considered, i.e., the time-convolution (TC) equation and time-convolutionless (TCL) equation. That is, the full of the four cases are studied. It is turned out that the expression of the complex admittance obtained by using the relaxation method with the TC equation exactly coincides with that obtained by using the external-field method with the TC equation, while other two methods give different forms. It is also explicitly demonstrated that all the expressions of the complex admittance coincide with each other in the lowest Born approximation for the systemreservoir interaction. The formulae necessary for the higher order expansions in powers of the system-reservoir interaction are derived, and also the expressions of the admittance in the n-th order approximation are given. To characterize the TC and TCL methods, we study the expressions of the admittances of two exactly solvable models. Each exact form of admittance is compared with the results of the two methods in the lowest Born approximation. It is found that depending on the model, either of TC and TCL would be the better method.Comment: 34pages, no figur
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