476 research outputs found

    Properties of nonaqueous electrolytes Quarterly report, 20 Jun. - 19 Sep. 1967

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    Electrolyte preparation, and physical property and nuclear magnetic resonance structural studies of nonaqueous electrolyte

    Properties of nonaqueous electrolytes Sixth summary report, 20 Sep. 1967 - 19 Mar. 1968

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    Physical properties and structural studies on propylene carbonate, dimethyl formamide, and acetonitrile solvent electrolyte

    Fermion Pairing Dynamics in the Relativistic Scalar Plasma

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    Using many-body techniques we obtain the time-dependent Gaussian approximation for interacting fermion-scalar field models. This method is applied to an uniform system of relativistic spin-1/2 fermion field coupled, through a Yukawa term, to a scalar field in 3+1 dimensions, the so-called quantum scalar plasma model. The renormalization for the resulting Gaussian mean-field equations, both static and dynamical, are examined and initial conditions discussed. We also investigate solutions for the gap equation and show that the energy density has a single minimum.Comment: 21 pages, latex, 4 postscript figures, new sections, some literary changes, notation corrections, accepted for publication in Phys. Rev

    Dynamical correlations and collective excitations of Yukawa liquids

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    In dusty (complex) plasmas, containing mesoscopic charged grains, the grain-grain interaction in many cases can be well described through a Yukawa potential. In this Review we summarize the basics of the computational and theoretical approaches capable of describing many-particle Yukawa systems in the liquid and solid phases and discuss the properties of the dynamical density and current correlation spectra of three- and two-dimensional strongly coupled Yukawa systems, generated by molecular dynamics simulations. We show details of the ω(k)\omega(k) dispersion relations for the collective excitations in these systems, as obtained theoretically following the quasilocalized charge approximation, as well as from the fluctuation spectra created by simulations. The theoretical and simulation results are also compared with those obtained in complex plasma experiments.Comment: 54 pages, 31 figure

    Development of clinical value unit method for calculating patient costs

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    The objective of the study was to develop the clinical value unit method of allocating indirect costs to patient costs using clinical factors. The method was tested to determine whether it is a more reliable alternative to using the length of stay and marginal mark‐up allocation method. The method developed used data from a Polish specialist hospital. The study involved 4,026 patients grouped into nine diagnosis‐related groups (DRG). The study methodology involved a three stage approach: (a) identification of correlates of patient costs, (b) a comparison of the costs calculated using the clinical value unit method with the alternative methods: length of stay and marginal mark‐up methods,and (c) an estimation of the cost homogeneity of the DRGs. The study showed that length of stay cost allocation method may underestimate the proportion of indirect costs in patient costs for a short in‐patient stay and overestimate the cost for the patients with a long stay. The total costs estimated using the marginal mark‐up method were higher than those estimated with length of stay method. For most surgical procedures, the mean indirect costs are higher using clinical value unit method than when using length of stay or marginal mark‐up method. In all medical procedure cases, the mean indirect costs calculated using the clinical value unit method are in the range between marginal mark‐up and length of stay method. We also show that in all DRGs except one, that the coefficient of homogeneity for clinical value unit is higher than for length of stay or marginal mark‐up method. We conclude that the clinical value unit method of cost allocation is a more precise and reliable alternative than the other methods

    Investigation of the Role of Mitochondrial DNA in Multiple Sclerosis Susceptibility

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    Several lines of evidence suggest that mitochondrial genetic factors may influence susceptibility to multiple sclerosis. To explore this hypothesis further, we re-sequenced the mitochondrial genome (mtDNA) from 159 patients with multiple sclerosis and completed a haplogroup analysis including a further 835 patients and 1,506 controls. A trend towards over-representation of super-haplogroup U was the only evidence for association with mtDNA that we identified in these samples. In a parallel analysis of nuclear encoded mitochondrial genes, we also found a trend towards association with the complex I gene, NDUFS2. These results add to the evidence suggesting that variation in mtDNA and nuclear encoded mitochondrial genes may contribute to disease susceptibility in multiple sclerosis

    Measurement of Through-Going Particle Momentum By Means Of Multiple Scattering With The ICARUS T600 TPC

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    The ICARUS collaboration has demonstrated, following the operation of a 600 ton (T600) detector at shallow depth, that the technique based on liquid Argon TPCs is now mature. The study of rare events, not contemplated in the Standard Model, can greatly benefit from the use of this kind of detectors. In particular, a deeper understanding of atmospheric neutrino properties will be obtained thanks to the unprecedented quality of the data ICARUS provides. However if we concentrate on the T600 performance, most of the ΜΌ\nu_\mu charged current sample will be partially contained, due to the reduced dimensions of the detector. In this article, we address the problem of how well we can determine the kinematics of events having partially contained tracks. The analysis of a large sample of atmospheric muons collected during the T600 test run demonstrate that, in case the recorded track is at least one meter long, the muon momentum can be reconstructed by an algorithm that measures the Multiple Coulomb Scattering along the particle's path. Moreover, we show that momentum resolution can be improved by a factor two using an algorithm based on the Kalman Filtering technique

    DADA: data assimilation for the detection and attribution of weather and climate-related events

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    A new nudging method for data assimilation, delay‐coordinate nudging, is presented. Delay‐coordinate nudging makes explicit use of present and past observations in the formulation of the forcing driving the model evolution at each time step. Numerical experiments with a low‐order chaotic system show that the new method systematically outperforms standard nudging in different model and observational scenarios, also when using an unoptimized formulation of the delay‐nudging coefficients. A connection between the optimal delay and the dominant Lyapunov exponent of the dynamics is found based on heuristic arguments and is confirmed by the numerical results, providing a guideline for the practical implementation of the algorithm. Delay‐coordinate nudging preserves the easiness of implementation, the intuitive functioning and the reduced computational cost of the standard nudging, making it a potential alternative especially in the field of seasonal‐to‐decadal predictions with large Earth system models that limit the use of more sophisticated data assimilation procedures
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