178,529 research outputs found

    Persistent Problems in Medical Care

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    Fossil Glasses Produced by Impact of Meteorites, Asteroids and Possibly Comets with the Planet Earth

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    In recent times one of the most intriguing mysteries of geology bas been the occurrence of aerodynamically-shaped glasses on five continents of the earth. These glasses under discussion are obviously not of fulgurite origin. Recent research indicates that these glasses known as tektites are ~he result of meteorite, asteroid, or possibly comet impact. Impact glasses, in general, differ from volcanic glasses in that they are lower in water content, have lower gallium and germanium contents, and are not necessarily in magmatically unstable continental areas

    Analysis of F and G subdwarfs. 3 - An abundance analysis of the subdwarf mu Cassiopeia

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    Model atmospheric abundance analysis of subdwarf micron Cassiopeia constellatio

    Hazard's Toll: The Costs of Inaction at the Salton Sea

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    The objective of this report is to estimate the costs of inaction - defined as the absence of any large-scale revitalization or air quality management project - at the Salton Sea, to provide decision-makers and the general public with information for deciding on a path forward

    Constrained Molecular Dynamics Simulations of Atomic Ground-States

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    Constrained molecular dynamics(CoMD) model, previously introduced for nuclear dynamics, has been extended to the atomic structure and collision calculations. Quantum effects corresponding to the Pauli and Heisenberg principle are enforced by constraints, in a parameter-free way. Our calculations for small atomic system, H, He, Li, Be, F reproduce the ground-state binding energies within 3%, compared with the results of quantum mechanical Hartree-Fock calculations.Comment: 3 pages, 2 figure

    Diffractive energy spreading and its semiclassical limit

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    We consider driven systems where the driving induces jumps in energy space: (1) particles pulsed by a step potential; (2) particles in a box with a moving wall; (3) particles in a ring driven by an electro-motive-force. In all these cases the route towards quantum-classical correspondence is highly non-trivial. Some insight is gained by observing that the dynamics in energy space, where nn is the level index, is essentially the same as that of Bloch electrons in a tight binding model, where nn is the site index. The mean level spacing is like a constant electric field and the driving induces long range hopping 1/(n-m).Comment: 19 pages, 11 figs, published version with some improved figure
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