33,041 research outputs found

    Welfarism and the Assessments of Social Decision Rules

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    Is there a role for thoracic aortic calcium to fine-tune cardiovascular risk prediction?

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    Screening asymptomatic subjects to streamline measures for the prevention of cardiovascular events remains a major challenge. The established primary prevention risk-scoring methods use equations derived from large prospective cohort studies, but further fine-tuning of cardiovascular risk assessment remains important as 25 % of individuals with low estimated risk may experience cardiac events. Independent studies provided evidence that extended risk assessment using coronary artery calcium quantification may improve risk stratification as it can lead to reclassification of persons at increased risk. Particularly in intermediate-risk subjects, coronary artery calcium scoring can help to correctly identify individuals at highest risk. Data on the extent of calcification of the ascending and descending thoracic aorta might be useful for additional cardiovascular risk stratification. Future analyses and studies will be required to answer the question of whether the implementation of such data may allow further fine-tuning of cardiovascular risk prediction in specific subpopulations—for instance in women or men with an increased risk of stroke and/or symptomatic peripheral vascular diseas

    Large scale Gd-beta-diketonate based organic liquid scintillator production for antineutrino detection

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    Over the course of several decades, organic liquid scintillators have formed the basis for successful neutrino detectors. Gadolinium-loaded liquid scintillators provide efficient background suppression for electron antineutrino detection at nuclear reactor plants. In the Double Chooz reactor antineutrino experiment, a newly developed beta-diketonate gadolinium-loaded scintillator is utilized for the first time. Its large scale production and characterization are described. A new, light yield matched metal-free companion scintillator is presented. Both organic liquids comprise the target and "Gamma Catcher" of the Double Chooz detectors.Comment: 16 pages, 4 figures, 5 table

    Large scale Gd-beta-diketonate based organic liquid scintillator production for antineutrino detection

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    Over the course of several decades, organic liquid scintillators have formed the basis for successful neutrino detectors. Gadolinium-loaded liquid scintillators provide efficient background suppression for electron antineutrino detection at nuclear reactor plants. In the Double Chooz reactor antineutrino experiment, a newly developed beta-diketonate gadolinium-loaded scintillator is utilized for the first time. Its large scale production and characterization are described. A new, light yield matched metal-free companion scintillator is presented. Both organic liquids comprise the target and "Gamma Catcher" of the Double Chooz detectors.Comment: 16 pages, 4 figures, 5 table

    Large scale Gd-beta-diketonate based organic liquid scintillator production for antineutrino detection

    Full text link
    Over the course of several decades, organic liquid scintillators have formed the basis for successful neutrino detectors. Gadolinium-loaded liquid scintillators provide efficient background suppression for electron antineutrino detection at nuclear reactor plants. In the Double Chooz reactor antineutrino experiment, a newly developed beta-diketonate gadolinium-loaded scintillator is utilized for the first time. Its large scale production and characterization are described. A new, light yield matched metal-free companion scintillator is presented. Both organic liquids comprise the target and "Gamma Catcher" of the Double Chooz detectors.Comment: 16 pages, 4 figures, 5 table

    Effective dynamics using conditional expectations

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    The question of coarse-graining is ubiquitous in molecular dynamics. In this article, we are interested in deriving effective properties for the dynamics of a coarse-grained variable ξ(x)\xi(x), where xx describes the configuration of the system in a high-dimensional space Rn\R^n, and ξ\xi is a smooth function with value in R\R (typically a reaction coordinate). It is well known that, given a Boltzmann-Gibbs distribution on xRnx \in \R^n, the equilibrium properties on ξ(x)\xi(x) are completely determined by the free energy. On the other hand, the question of the effective dynamics on ξ(x)\xi(x) is much more difficult to address. Starting from an overdamped Langevin equation on xRnx \in \R^n, we propose an effective dynamics for ξ(x)R\xi(x) \in \R using conditional expectations. Using entropy methods, we give sufficient conditions for the time marginals of the effective dynamics to be close to the original ones. We check numerically on some toy examples that these sufficient conditions yield an effective dynamics which accurately reproduces the residence times in the potential energy wells. We also discuss the accuracy of the effective dynamics in a pathwise sense, and the relevance of the free energy to build a coarse-grained dynamics

    Planetary astronomy program

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    Observations and analyses of asteroids, Trojans and cometary nuclei are presented. Spectrophotometry was used to observe the cometary nuclei. The spectra are plotted as a function of semimajor axis and eccentricity. Trojans and other asteroids at great solar distances show a variety of spectra, many of them quite red despite the low measured albedoes for many of these asteroids. The asteroid spectra are grouped according to diameter and taxonomic class

    Symmetries and Triplet Dispersion in a Modified Shastry-Sutherland Model for SrCu_2(BO_3)_2

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    We investigate the one-triplet dispersion in a modified Shastry-Sutherland Model for SrCu_2(BO_3)_2 by means of a series expansion about the limit of strong dimerization. Our perturbative method is based on a continuous unitary transformation that maps the original Hamiltonian to an effective, energy quanta conserving block diagonal Hamiltonian H_{eff}. The dispersion splits into two branches which are nearly degenerated. We analyse the symmetries of the model and show that space group operations are necessary to explain the degeneracy of the dispersion at k=0 and at the border of the magnetic Brillouin zone. Moreover, we investigate the behaviour of the dispersion for small |k| and compare our results to INS data.Comment: 9 pages, 8 figures accepted by J. Phys.: Condens. Matte
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