32,861 research outputs found

    On retarded evolution of protostars

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    Mechanisms of protostar evolution restraint

    On the formation of the moon by accretion of solar or planetary material

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    Evolutionary theory for moon based on accretion of solar or planetary material and using flow dat

    Measuring Brief (Fossil Creek Watchers, Inc.)

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    Results of literature search on dielectric properties and electron interaction phenomena related to spacecraft charging

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    The objective of the literature search was to determine the required material properties and electron interaction parameters needed for modeling charge buildup and breakdown in insulators. A brief overview of the results of the literature search is given. A partial list of the references covered is included in a bibliography. Although inorganic insulators were also considered in the search, coverage is limited to the organics, primarily Kapton and Teflon

    A combined R-matrix eigenstate basis set and finite-differences propagation method for the time-dependent Schr\"{od}dinger equation: the one-electron case

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    In this work we present the theoretical framework for the solution of the time-dependent Schr\"{o}dinger equation (TDSE) of atomic and molecular systems under strong electromagnetic fields with the configuration space of the electron's coordinates separated over two regions, that is regions II and IIII. In region II the solution of the TDSE is obtained by an R-matrix basis set representation of the time-dependent wavefunction. In region IIII a grid representation of the wavefunction is considered and propagation in space and time is obtained through the finite-differences method. It appears this is the first time a combination of basis set and grid methods has been put forward for tackling multi-region time-dependent problems. In both regions, a high-order explicit scheme is employed for the time propagation. While, in a purely hydrogenic system no approximation is involved due to this separation, in multi-electron systems the validity and the usefulness of the present method relies on the basic assumption of R-matrix theory, namely that beyond a certain distance (encompassing region II) a single ejected electron is distinguishable from the other electrons of the multi-electron system and evolves there (region II) effectively as a one-electron system. The method is developed in detail for single active electron systems and applied to the exemplar case of the hydrogen atom in an intense laser field.Comment: 13 pages, 6 figures, submitte

    Solar cell radiation response near the interface of different atomic number materials

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    The response of cobalt 60 irradiated N/P silicon solar cells was measured as a function of the atomic number of the medium adjacent to the cell and the direction of the gamma ray beam. The interpositioning of various thicknesses of aluminum between the adjacent material and the cell had the effect of moving the cell to various locations in an approximate monatomic numbered medium. Using this technique the solar cell response was determined at various distances from the interface for gold and beryllium. The results were compared with predictions based upon ionization chamber measurements of dose perturbations in aluminum and found to agree within five percent. Ionization chamber data was then used to estimate the influence of various base contact materials

    Patient safety in Europe: medication errors and hospital-acquired infections

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    The Report was commissioned by the European Federation of Nurses Associations (EFN) in November 2007 in order to support its policy statements on Patient Safety (June 2004). In that statement the EFN declares its belief that European Union health services should operate within a culture of safety that is based on working towards an open culture and the immediate reporting of mistakes; exchanging best practice and research; and lobbying for the systematic collection of information and dissemination of research findings. This Report adressess specifically the culture of highly reliable organisations using the work of James Reason (2000). Medication errors and hospital-acquired infections are examined in line with the Reprt´s parameters and a range of European studies are used as evidence. An extensive reference list is provided that allows EFN to explore work in greater detail as required

    Accurate Adiabatic Connection Curve Beyond the Physical Interaction Strength

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    The adiabatic connection curve of density functional theory (DFT) is accurately calculated beyond the physical interaction strength for Hooke's atom, two interacting electrons in a harmonic well potential. Extrapolation of the accurate curve to the infinite coupling limit agrees well with the strictly correlated electron (SCE) hypothesis but the approach to this limit is more complex. The interaction strength interpolation is shown to be a good, but not perfect, fit to the adiabatic curve. Arguments about the locality of functionals and convexity of the adiabatic connection curve are examined in this regime.Comment: 7 pages, 5 figure

    Suicide substrate reaction-diffusion equations: varying the source

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    The suicide substrate reaction is a model for certain enzyme-inhibiting drugs. This reaction system is examined assuming that the substrate diffuses freely while the enzyme remains fixed. Two sets of initial and boundary conditions are examined: one modelling an instantaneous point source, akin to an injection of substrate, the other, a continuous point source, akin to a continuing influx, or intravenous drip, of substrate. The quasi-steady-state assumption is applied to obtain analytical solutions for a limited parameter space. Finally, further applications of numerical and analytical experimentation on pharmaceutical mechanisms are described
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