2,564 research outputs found

    A Proposed Livestock Research Program for Alaska

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    This report presents, primarily, areas of research and research goals on range management and beef cattle production that 1) appear to be most urgent and 2) that appear attainable within the next few years without a great expansion of personnel, equipment and funds. Other areas of research and development in the livestock industry (not including dairy) are discussed briefly. Present trends in agricultural research and recommendations for an expanded research program in animal husbandry are given. Some of these recommendations have appeared in other reports and are singled out here to emphasize their importance to a livestock research program for Alaska.Alaska's feedbase studies -- Beef cattle production research -- Other livestock research -- Recommendations -- Appendi

    A Proposed Livestock Research Program for Alaska

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    This report presents, primarily, areas of research and research goals on range management and beef cattle production that 1) appear to be most urgent and 2) that appear attainable within the next few years without a great expansion of personnel, equipment and funds. Other areas of research and development in the livestock industry (not including dairy) are discussed briefly. Present trends in agricultural research and recommendations for an expanded research program in animal husbandry are given. Some of these recommendations have appeared in other reports and are singled out here to emphasize their importance to a livestock research program for Alaska.Alaska's feedbase studies -- Beef cattle production research -- Other livestock research -- Recommendations -- Appendi

    APPROACH D: MULTIPLE PRICING

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    Demand and Price Analysis,

    Community support for the university

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    Cumulant expansion for phonon contributions to the electron spectral function

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    We describe an approach for calculations of phonon contributions to the electron spectral function, including both quasiparticle properties and satellites. The method is based on a cumulant expansion for the retarded one-electron Green's function and a many-pole model for the electron self-energy. The electron-phonon couplings are calculated from the Eliashberg functions, and the phonon density of states is obtained from a Lanczos representation of the phonon Green's function. Our calculations incorporate ab initio dynamical matrices and electron-phonon couplings from the density functional theory code ABINIT. Illustrative results are presented for several elemental metals and for Einstein and Debye models with a range of coupling constants. These are compared with experiment and other theoretical models. Estimates of corrections to Migdal's theorem are obtained by comparing with leading order contributions to the self-energy, and are found to be significant only for large electron-phonon couplings at low temperatures

    Suppression of carrier induced ferromagnetism by composition and spin fluctuations in diluted magnetic semiconductors

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    We suggest an approach to account for spatial (composition) and thermal fluctuations in "disordered" magnetic models (e.g. Heisenberg, Ising) with given spatial dependence of magnetic spin-spin interaction. Our approach is based on introduction of fluctuating molecular field (rather than mean field) acting between the spins. The distribution function of the above field is derived self-consistently. In general case this function is not Gaussian, latter asymptotics occurs only at sufficiently large spins (magnetic ions) concentrations nin_i. Our approach permits to derive the equation for a critical temperature TcT_c of ferromagnetic phase transition with respect to the above fluctuations. We apply our theory to the analysis of influence of composition fluctuations on TcT_c in diluted magnetic semiconductors (DMS) with RKKY indirect spin-spin interaction.Comment: 6 pages, 2 figure

    South Pole Telescope Software Systems: Control, Monitoring, and Data Acquisition

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    We present the software system used to control and operate the South Pole Telescope. The South Pole Telescope is a 10-meter millimeter-wavelength telescope designed to measure anisotropies in the cosmic microwave background (CMB) at arcminute angular resolution. In the austral summer of 2011/12, the SPT was equipped with a new polarization-sensitive camera, which consists of 1536 transition-edge sensor bolometers. The bolometers are read out using 36 independent digital frequency multiplexing (DfMux) readout boards, each with its own embedded processors. These autonomous boards control and read out data from the focal plane with on-board software and firmware. An overall control software system running on a separate control computer controls the DfMux boards, the cryostat and all other aspects of telescope operation. This control software collects and monitors data in real-time, and stores the data to disk for transfer to the United States for analysis

    Channel Closing in Multiphoton Ionization of Mg

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    Experimental data are presented showing the channel closing of four-photon ionization of Mg. It is shown that, for circularly polarized light, the ionization versus intensity spectra exhibit sharp breaks from the normal I4 intensity dependence at the critical intensity where the channel closing occurs. Above the critical intensity, the population of Rydberg states which survives the laser pulse is observed. The residual Rydberg population is found to be greatly reduced for linearly polarized light due to the relatively large probability of ionization of the low-angular-momentum Rydberg states. The data are in good agreement with a model which includes averaging over the spatial profile of the laser
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