7,720 research outputs found

    Influence of coherent mesoscale structures on satellite-based Doppler lidar wind measurements

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    Efforts to develop display routines for overlaying gridded and nongridded data sets are discussed. The primary objective is to have the capability to review global patterns of winds and lidar samples; to zoom in on particular wind features or global areas; and to display contours of wind components and derived fields (e.g., divergence, vorticity, deformation, etc.). Current considerations in support of a polar orbiting shuttle lidar mission are discussed. Ground truth for a shuttle lidar experiment may be limited to fortuitous alignment of lidar wind profiles and scheduled rawinsonde profiles. Any improvement on this would require special rawinsonde launches and/or optimization of the shuttle orbit with global wind measurement networks

    Improved laboratory gradiometer can be a field survey instrument

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    Improvements made to quartz gradiometer minimize or eliminate disturbing effects from known error sources and permit sensitivity of + or - 1 times 10 to the minus 9th power/sec sq or better and measuring accuracy of + or - 5 times 10 to the minus 9th power/sec sq

    An agglomeration-based massively parallel non-overlapping additive Schwarz preconditioner for high-order discontinuous Galerkin methods on polytopic grids

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    In this article we design and analyze a class of two-level non-overlapping additive Schwarz preconditioners for the solution of the linear system of equations stemming from discontinuous Galerkin discretizations of second-order elliptic partial differential equations on polytopic meshes. The preconditioner is based on a coarse space and a non-overlapping partition of the computational domain where local solvers are applied in parallel. In particular, the coarse space can potentially be chosen to be non-embedded with respect to the finer space; indeed it can be obtained from the fine grid by employing agglomeration and edge coarsening techniques. We investigate the dependence of the condition number of the preconditioned system with respect to the diffusion coefficient and the discretization parameters, i.e., the mesh size and the polynomial degree of the fine and coarse spaces. Numerical examples are presented which confirm the theoretical bounds

    Alternative AMTA and Loan Rate Options for Program Crops With Counter Cyclical Payments Triggered at the National and State Level

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    This analysis focuses on four policy options, based on national formulas where implications are examined for varying levels of loan rates and base AMTA payment rates.Agricultural and Food Policy,

    Evaluation of Alternative Base Periods for a National Counter Cyclical Payment Program for Rice, Upland Cotton, Corn, Wheat, Soybeans and Sorghum

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    A risk analysis of a national counter cyclical payment (CCP) program for six crops was completed for one year. National planted acre yield risk over the 1986-2000 period was used with FAPRI’s stochastic projection of crop prices for 2001 in the analysis. Four alternative base periods for triggering a CCP were evaluated. Three Added AMTA scenarios and a Base scenario of no additional market loss or CCP were also run for each of the crops.Agricultural and Food Policy,

    Gravity gradient preliminary investigations, part 2: Lunar tidal gravity gradients and stresses (exhibit C)

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    Preliminary analysis of the gravity gradients associated with gravity tides on the moon caused by the earth indicates that the relative changes in the gradients are very irregular, and large, and about 15 times greater than those experienced on earth. Thus gradients, in preference to gravity tides themselves, may well be an important key in correlating tide effects with lunar transient events and moonquakes, and also in determining triggering mechanisms for crustal movement and faulting. Preliminary analysis of lunar crustal stresses and strains caused by lunar gravity tides indicates that these factors may be more direct causative agents or triggering mechanisms. In particular, the cubic dilation undergoes relatively large changes and is about 11 times greater on the moon than on earth. Thus it should be correspondingly more important

    Analysis of Representative Rice Farms Under H.R. 2646 and the Continuation of the FAIR Act

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    In anticipation of the new farm bill, seventeen representative rice farms from six different rice-producing states have been analyzed to compare the continuation of the FAIR Act provisions with the House proposal, H.R. 2646. Each farm was simulated assuming each policy would be in place for the next five-year period, or 2002-2006. A full description of each of the farms can be found in the Appendix.Agribusiness, Agricultural and Food Policy, Crop Production/Industries,
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