30,249 research outputs found

    Scalar gain interpretation of large order filters

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    A technique is developed which demonstrates how to interpret a large fully-populated filter gain matrix as a set of scalar gains. The inverse problem is also solved, namely, how to develop a large-order filter gain matrix from a specified set of scalar gains. Examples are given to illustrate the method

    Constraints of solar flare particle transport models from anisotropy observations at Voyager 1

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    In general a particle transport model for energetic solar flare particles contains a number of free parameters which are determined by fitting various features of observed particle events. Frequently the parameter values are not uniquely determined. In order to place tighter constraints on the models, the anisotropy of 1 and 25 MeV/nuc protons and helium nuclei were examined during the 22 November 1977 solar particle event using data from the LECP experiment on Voyager 1 at 1.6 AU. These observations were combined with the time intensity profiles at Voyager 1 and at 1 AU from ISEE-1 and IMP-8 to determine the magnitude and radial dependence of the interplanetary diffusion coefficient and the required injection duration at the sun. The first order anisotropy amplitudes for both 1 MeV and 25 MeV protons are observed to decrease from maximum values (approx. 1) during the event onset at Voyager 1 to values consistent with convection in the solar wind at about 3 days into the event decay phase. The intensity and anisotropy profiles at 1.6 AU are consistent with predictions of diffusive transport with a modest mean free path (lambda = approx. 0.1 AU)

    Antarctic meteorite descriptions, 1980

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    Specimens found in the Alan Hills area include 361 ordinary chondrites, 4 carbonaceous chondrites, 6 achondrites, and 2 irons. Thirteen specimens measured over 11 cm in diameter and 69 between 5 to 10 cm in diameter are reported. The remainder of the finds were small, and many were paired. One of the irons was estimated to weigh about 20 kilograms

    Seed Yield Prediction Models of Four Common Moist-Soil Plant Species in Texas

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    Seed production by moist-soil plant species often varies within and among managed wetlands and on larger landscapes. Quantifying seed production of moist-soil plants can be used to evaluate wetland management strategies and estimate wetland energetic carrying capacity, specifically for waterfowl. In the past, direct estimation techniques were used, but due to excessive personnel and time costs, other indirect methods have been developed. Because indirect seed yield models do not exist for moist-soil plant species in east-central or coastal Texas, we developed direct and indirect methods to model seed production on regional managed wetlands. In September 2004 and 2005, we collected Echinochloa crusgalli (barnyard grass), E. walterii (wild millet), E. colona (jungle rice), and Oryza sativa (cultivated rice) for phytomorphological measurements and seed yield modeling. Initial simple linear and point of origin regression analyses demonstrate strong relationships (P \u3c 0.001) among phytomorphological and dot grid methods in predicting seed production for all four species. These models should help regional wetland managers evaluate moist-soil management success and create models for seed production for other moist-soil plants in this region

    On optimum Hamiltonians for state transformations

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    For a prescribed pair of quantum states |psi_I> and |psi_F> we establish an elementary derivation of the optimum Hamiltonian, under constraints on its eigenvalues, that generates the unitary transformation |psi_I> --> |psi_F> in the shortest duration. The derivation is geometric in character and does not rely on variational calculus.Comment: 5 page
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