1,480 research outputs found

    Synthetic spectra of H Balmer and HeI absorption lines. I: Stellar library

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    We present a grid of synthetic profiles of stellar H Balmer and HeI lines at optical wavelengths with a sampling of 0.3 A. The grid spans a range of effective temperature 4000 K < Teff < 50000 K, and gravity 0.0 < log g < 5.0 at solar metallicity. For Teff > 25000 K, NLTE stellar atmosphere models are computed using the code TLUSTY (Hubeny 1988). For cooler stars, Kurucz (1993) LTE models are used to compute thesynthetic spectra. The grid includes the profiles of the high-order hydrogen Balmer series and HeI lines for effective temperatures and gravities that have not been previously synthesized. The behavior of H8 to H13 and HeI 3819 with effective temperature and gravity is very similar to that of the lower terms of the series (e.g. Hb) and the other HeI lines at longer wavelengths; therefore, they are suited for the determination of the atmospheric parameters of stars. These lines are potentially important to make predictions for these stellar absorption features in galaxies with active star formation. Evolutionary synthesis models of these lines for starburst and post-starburst galaxies are presented in a companion paper. The full set of the synthetic stellar spectra is available for retrieval at our website http://www.iaa.es/ae/e2.html and http://www.stsci.edu/science/starburst/ or on request from the authors at [email protected]: To be published in ApJS. 28 pages and 12 figure

    Non-LTE Models and Theoretical Spectra of Accretion Disks in Active Galactic Nuclei

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    We present self-consistent models of the vertical structure and emergent spectrum of AGN accretion disks. The central object is assumed to be a supermassive Kerr black hole. We demonstrate that NLTE effects and the effects of a self-consistent vertical structure of a disk play a very important role in determining the emergent radiation, and therefore should be taken into account. In particular, NLTE models exhibit a largely diminished H I Lyman discontinuity when compared to LTE models, and the He II discontinuity appears strongly in emission for NLTE models. Consequently, the number of ionizing photons in the He II Lyman continuum predicted by NLTE disk models is by 1 - 2 orders of magnitude higher than that following from the black-body approximation. This prediction has important implications for ionization models of AGN broad line regions, and for models of the intergalactic radiation field and the ionization of helium in the intergalactic medium.Comment: 11 pages; 2 postscript figures; LaTeX, AASPP4 macro; to appear in the Astrophysical Journal (Letters

    General practitioners' willingness to pay for continuing medical education in a fee-for-service universal coverage health care system [article]

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    Abstract: Background: Sponsoring of medical meetings by life science companies has led to reduced participation fees for physicians but questions potential drawbacks. Ongoing discussions are proposing to ban such sponsoring which may increase participation fees. Objectives: To evaluate factors associated with general practitioners' willingness to pay for medical meetings, their support of a binding legislation prohibiting sponsoring and their opinion on alternative financing options. Methods: An anonymous web-based questionnaire was sent to 447 general practitioners' of one state in Switzerland, identified through their affiliation to a medical association. Results: Of the 115 physicians answering, 48% were willing to pay more than what they currently pay for medical meetings and 79% disagreed that sponsoring introduced a bias in their own prescription practices. In univariate analyses, factors most associated with physician's willingness to pay were perception of a bias in peers prescription practices (OR=6.67; 95% CI: 1.60-27.74), group practice (OR=3.01; 95% CI: 0.94-9.65) and having &lt;4 meetings with sales representatives per month (OR=2.39; 95% CI: 0.91-6.33). 78% did not support the introduction of a binding legislation and 56% were in favor of creating a general fund set up by life science companies and centrally administered by an independent body as an alternative financing option. Conclusions: Our results suggest that almost half of physicians surveyed were willing to pay more than what they currently pay for medical meetings and that an independent body that would centrally administer a general fund set up by life science companies might be better received by general practitioners' than a legislation banning the sponsoring of medical meetings by life science companies

    Fungos em acículas da serapilheira de Pinus taeda L. em povoamentos com diferentes idades.

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    A ação fúngica na decomposição e mineralização da serapilheira em florestas permite a ciclagem de nutrientes, sua produtividade e sustentabilidade. Este estudo avaliou a diversidade dos fungos presentes durante a decomposição de acículas de Pinus taeda sob povoamentos com 6, 10, 14, 17 e 29 anos de idade, em Três Barras, SC, Brasil. Acículas recém-caídas foram coletadas em abril/2006, fragmentadas, submetidas a lavagens sucessivas em água destilada estéril e implantadas em placas de Petri contendo meio BDA mais ácido láctico. Os fungos encontrados pertencem aos gêneros: Aureobasidium, Candida, Cladosporium, Exophiala, Fusarium, Penicillium, Pestalotia, Rhizoctonia, Rhizopus, Trichoderma e Tubercularia. Os gêneros Pestalotia, Trichoderma e Penicillium foram os mais freqüentes. A diversidade fúngica foi maior nos plantios mais velhos e deve garantir o retorno dos nutrientes e a sustentabilidade em rotações mais longas de pínus

    Communication: Non-monotonic supersaturation dependence of the nucleus size of crystals with anisotropically interacting molecules.

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    We study the nucleation of model two-dimensional crystals formed from anisotropically interacting molecules using kinetic Monte Carlo simulations and the forward flux sampling algorithm. The growth probability P(n) of a cluster of n molecules is measured while the supersaturation s and interaction anisotropy of the molecules are varied, in order to gain insight into the nucleation mechanism. It is found that with increasing degree of interaction anisotropy the nucleus size (defined as the cluster size at which P(n) = 0.5) can increase with increasing s, with sharp jumps at certain s values. Analysis of the cluster shape reveals that nucleation in the system studied is of a non-standard form, in that it embodies elements of both the classical nucleation theory and the density functional theory frameworks

    Publication trends of shared decision making in 15 high impact medical journals: a full-text review with bibliometric analysis.

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    BACKGROUND: Shared Decision Making (SDM) is increasingly advocated as a model for medical decision making. However, there is still low use of SDM in clinical practice. High impact factor journals might represent an efficient way for its dissemination. We aimed to identify and characterize publication trends of SDM in 15 high impact medical journals. METHODS: We selected the 15 general and internal medicine journals with the highest impact factor publishing original articles, letters and editorials. We retrieved publications from 1996 to 2011 through the full-text search function on each journal website and abstracted bibliometric data. We included publications of any type containing the phrase "shared decision making" or five other variants in their abstract or full text. These were referred to as SDM publications. A polynomial Poisson regression model with logarithmic link function was used to assess the evolution across the period of the number of SDM publications according to publication characteristics. RESULTS: We identified 1285 SDM publications out of 229,179 publications in 15 journals from 1996 to 2011. The absolute number of SDM publications by journal ranged from 2 to 273 over 16 years. SDM publications increased both in absolute and relative numbers per year, from 46 (0.32% relative to all publications from the 15 journals) in 1996 to 165 (1.17%) in 2011. This growth was exponential (P &lt; 0.01). We found fewer research publications (465, 36.2% of all SDM publications) than non-research publications, which included non-systematic reviews, letters, and editorials. The increase of research publications across time was linear. Full-text search retrieved ten times more SDM publications than a similar PubMed search (1285 vs. 119 respectively). CONCLUSION: This review in full-text showed that SDM publications increased exponentially in major medical journals from 1996 to 2011. This growth might reflect an increased dissemination of the SDM concept to the medical community

    Knowledge Annotation within Research Data Management System for Oxygen-Free Production Technologies

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    The comprehensive implementation of digital technologies in product manufacturing leads to changes in engineering processes and requires new approaches to data management. An important role belongs to the processes of organizing the collection, storage and reuse of research data obtained and used in the process of product, system or technology development, taking into account the FAIR data principles. This article describes a Research Data Management System for the organization of documentation and measurement requests in the research and development of new oxygen-free production technologies

    Nucleon-nucleon elastic scattering analysis to 2.5 GeV

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    A partial-wave analysis of NN elastic scattering data has been completed. This analysis covers an expanded energy range, from threshold to a laboratory kinetic energy of 2.5 GeV, in order to include recent elastic pp scattering data from the EDDA collaboration. The results of both single-energy and energy-dependent analyses are described.Comment: 23 pages of text. Postscript files for the figures are available from ftp://clsaid.phys.vt.edu/pub/said/n
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