325 research outputs found

    Measuring snow cover using satellite imagery during 1973 and 1974 melt season: North Santiam, Boise, and Upper Snake Basins, phase 1

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    Measurements are examined of snow coverage during the snow-melt season in 1973 and 1974 from LANDSAT imagery for the three Columbia River Subbasins. Satellite derived snow cover inventories for the three test basins were obtained as an alternative to inventories performed with the current operational practice of using small aircraft flights over selected snow fields. The accuracy and precision versus cost for several different interactive image analysis procedures was investigated using a display device, the Electronic Satellite Image Analysis Console. Single-band radiance thresholding was the principal technique employed in the snow detection, although this technique was supplemented by an editing procedure involving reference to hand-generated elevation contours. For each data and view measured, a binary thematic map or "mask" depicting the snow cover was generated by a combination of objective and subjective procedures. Photographs of data analysis equipment (displays) are shown

    Modeling the Influence of Energy and Climate Megatrends on Future Costs and Benefits of Marsh Creation in the Mississippi Delta

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    Over 25% of Mississippi delta (MRDP) wetlands were lost over the past century. There is currently a major effort to restore the MRDP focused on a 50-year time horizon, a period during which the energy system and climate will change dramatically. I modeled hydraulic dredging to sustain marsh from 2016-2066 and 2016-2100 under a range of scenarios for sea level rise, energy price, and management regimes. A marsh elevation model was calibrated to data from MRDP marshes. I developed a model to simulate dredging costs based on the price of crude oil and a project efficiency factor. Crude oil prices were projected using forecasts from global energy models. The costs to sustain marsh between 2016 and 2100 changed from 128,000ha−1inthenochangescenarioto 128,000 ha-1 in the no change scenario to ~1,010,000 ha-1 in the worst-case scenario in sea level rise and energy price, an ~8-fold increase. Increasing suspended sediment load raised created marsh lifespan and decreased long term dredging costs. Created marsh lifespan changed nonlinearly with dredging fill elevation and suspended sediment level. Costs and benefits of marsh creation can be optimized by adjusting dredging fill elevations based on the local sediment regime. Regardless of management scenario, sustaining the MRDP with hydraulic dredging suffered declining returns on investment due to the convergence of energy and climate. Marsh creation will likely become unaffordable in the mid to late 21st century, especially if river sediment diversions are not constructed before 2030. Planners must take into consideration coupled energy and climate scenarios for long-term risk assessments and adjust restoration goals accordingly

    Analysis of ATS photographs using a specially designed electronic console, phase 1 Final report, 8 Oct. 1969 - 8 Oct. 1970

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    Evaluation of capabilities of electronic display system used in analysis of ATS cloud photograph

    Perception of Nuclear Energy and Coal in France and the Netherlands

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    This study focuses on the perception of large scale application of nuclear energy and coal in the Netherlands and France. The application of these energy-sources and the risks and benefits are judged differently by various group in society. In Europe, France has the highest density of nuclear power plants and the Netherlands has one of the lowest. In both countries scientists and social scientists completed a questionnaire assessing the perception of the large scale application of both energy sources. Furthermore, a number of variables relating to the socio cultural and political circumstances were measured. The results indicate that the French had a higher risk perception and a more negative attitude toward nuclear power than the Dutch. But they also assess the benefits of the use of nuclear power to be higher. Explanations for these differences are discussed

    Formulae for zero-temperature conductance through a region with interaction

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    The zero-temperature linear response conductance through an interacting mesoscopic region attached to noninteracting leads is investigated. We present a set of formulae expressing the conductance in terms of the ground-state energy or persistent currents in an auxiliary system, namely a ring threaded by a magnetic flux and containing the correlated electron region. We first derive the conductance formulae for the noninteracting case and then give arguments why the formalism is also correct in the interacting case if the ground state of a system exhibits Fermi liquid properties. We prove that in such systems, the ground-state energy is a universal function of the magnetic flux, where the conductance is the only parameter. The method is tested by comparing its predictions with exact results and results of other methods for problems such as the transport through single and double quantum dots containing interacting electrons. The comparisons show an excellent quantitative agreement.Comment: 18 pages, 18 figures; to appear in Phys. Rev.

    Dimensional Crossover in Quantum Antiferromagnets

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    The dimensional crossover in a spin-SS nearest neighbor Heisenberg antiferromagnet is discussed as it is tuned from a two-dimensional square lattice, of lattice spacing aa, towards a spin chain by varying the width LyL_y of a semi-infinite strip Lx×LyL_x\times L_y. For integer spins and arbitrary LyL_y, and for half integer spins with Ly/aL_y/a an arbitrary even integer, explicit analytical expressions for the zero temperature correlation length and the spin gap are given. For half integer spins and Ly/aL_y/a an odd inetger, it is shown that the c=1c=1 behavior of the SU(2)1SU(2)_1 WZW fixed point is squeezed out as the width Ly→∞L_y\to \infty; here cc is the conformal charge. The results specialized to S=1/2S=1/2 are relevant to spin-ladder systems.Comment: RevTeX, 4 pages, 1 embedded postscript figur

    Random matrix theory and QCD3QCD_3

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    We suggest that the spectral properties near zero virtuality of three dimensional QCD, follow from a Hermitean random matrix model. The exact spectral density is derived for this family of random matrix models both for even and odd number of fermions. New sum rules for the inverse powers of the eigenvalues of the Dirac operator are obtained. The issue of anomalies in random matrix theories is discussed.Comment: 10p., SUNY-NTG-94/1

    How is rape a weapon of war?: feminist international relations, modes of critical explanation and the study of wartime sexual violence

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    Rape is a weapon of war. Establishing this now common claim has been an achievement of feminist scholarship and activism and reveals wartime sexual violence as a social act marked by gendered power. But the consensus that rape is a weapon of war obscures important, and frequently unacknowledged, differences in ways of understanding and explaining it. This article opens these differences to analysis. Drawing on recent debates regarding the philosophy of social science in IR and social theory, it interprets feminist accounts of wartime sexual violence in terms of modes of critical explanation – expansive styles of reasoning that foreground particular actors, mechanisms, reasons and stories in the formulation of research. The idea of a mode of critical explanation is expanded upon through a discussion of the role of three elements (analytical wagers, narrative scripts and normative orientations) which accomplish the theoretical work of modes. Substantive feminist accounts of wartime sexual violence are then differentiated in terms of three modes – of instrumentality, unreason and mythology – which implicitly structure different understandings of how rape might be a weapon of war. These modes shape political and ethical projects and so impact not only on questions of scholarly content but also on the ways in which we attempt to mitigate and abolish war rape. Thinking in terms of feminist modes of critical explanation consequently encourages further work in an unfolding research agenda. It clarifes the ways in which an apparently commonality of position can conceal meaningful disagreements about human action. Exposing these disagreements opens up new possibilities for the analysis of war rape

    Critical Nature of Non-Fermi Liquid in Spin 3/2 Multipolar Kondo Model

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    A multipolar Kondo model of an impurity spin S_I=3/2 interacting with conduction electrons with spin s_c=3/2 is investigated using boundary conformal field theory. A two-channel Kondo (2CK) -like non-Fermi liquid (NFL) under the particle-hole symmetry is derived explicitly using a ``superspin absorption'' in the sector of a hidden symmetry, SO(5). We discuss the difference between the usual spin-1/2 2CK NFL fixed point and the present one. In particular, we find that, unlike the usual 2CK model, the low temperature impurity specific heat is proportional to temperature.Comment: 4 pages, 2 figure

    NRG approach to the transport through a finite Hubbard chain connected to reservoirs

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    We study the low-energy properties of a Hubbard chain of finite size N_C connected to two noninteracting leads using the numerical renormalization group (NRG) method. The results obtained for N_C = 3 and 4 show that the low-lying eigenstates have one-to-one correspondence with the free quasi-particle excitations of a local Fermi liquid. It enables us to determine the transport coefficients from the fixed-point Hamiltonian. At half-filling, the conductance for even N_C decreases exponentially with increasing U showing a tendency towards the development of a Mott-Hubbard gap. In contrast, for odd N_C, the Fermi-liquid nature of the low-energy states assures perfect transmission through the Kondo resonance. Our formulation to deduce the conductance from the fixed-point energy levels can be applied to various types of interacting systems.Comment: One typo found in Eq.(3) in previous version has been correcte
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