2,268 research outputs found

    Supernova electron capture rates for 55Co and 56Ni

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    We have calculated the Gamow-Teller strength distributions for the ground states and first excited states in 55Co and 56Ni. These calculations have been performed by shell model diagonalization in the pf shell using the KB3 interaction. The Gamow-Teller distributions are used to calculate the electron capture rates for typical presupernova conditions. Our 55Co rate is noticeably smaller than the presently adopted rate as it is dominated by weak low-lying transitions rather than the strong Gamow-Teller (GT) resonance which is located at a higher excitation energy in the daughter than usually parametrized. Although our 56Ni rate agrees with the presently adopted rate, we do not confirm the conventional parametrization of the GT centroid. Our results support general trends suggested on the basis of shell model Monte Carlo calculations.Comment: 4 pages, 4 figures, RevTeX 3.1, to appear in Phys. Lett.

    In the Battle for Reality: Social Documentaries in the U.S.

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    Provides an overview of documentaries that address social justice and democracy issues, and includes case studies of successful strategic uses of social documentaries

    What Keeps Social Documentaries from Audiences -- And How to Fix It

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    Offers an analysis and set of recommendations on how to improve today's market for social documentaries and make them far more accessible to people who want to use them

    Copyright, Free Speech, and the Public's Right to Know: How Journalists Think about Fair Use

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    This study, resulting from long-form interviews with 80 journalists, finds that journalistic mission is in peril, because of lack of clarity around copyright and fair use. Journalists' professional culture is highly conducive to a robust employment of their free speech rights under the copyright doctrine of fair use, but their actual knowledge of fair use practice is low. Where they have received education on copyright and fair use, it has often been erroneous. Ironically, when they do not know that they are using fair use, they nevertheless do so with a logic and reasoning that accords extremely well with today's courts' interpretation of the law. But when they have to actively make a decision about whether to employ fair use, they often resort to myths and misconceptions. Furthermore, they sometimes take unnecessary risks. The consequence of a failure to understand their free speech issues within the framework of fair use means that, when facing new practices or situations, journalists experience expense, delays and even failure to meet their mission of informing the public. These consequences are avoidable, with better and shared understanding of fair use within the experience of journalistic practice, whether it is original reporting, aggregation, within large institutions or a one-person outfit. Journalists need both to understand fair use and to articulate collectively the principles that govern its employment to meet journalistic mission

    The Good, the Bad, and the Confusing: User-Generated Video Creators on Copyright

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    Presents findings from a survey of independent producers of online video content. Examines producers' attitudes toward copyright, assumptions and knowledge about their use of others' intellectual property, and their stake in their own

    Shell model calculations of stellar weak interaction rates: I. Gamow-Teller distributions and spectra of nuclei in the mass range A=45-65

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    Electron capture and beta-decay rates on nuclei in the mass range A=45-65 play an important role in many astrophysical environments. The determination of these rates by large-scale shell model calculations is desirable, but it requires to reproduce the Gamow-Teller strength distributions and spectra of the pf shell nuclei. We show in this paper that large-scale shell model calculations, employing a slightly monopole-corrected version of the wellknown KB3 interaction, fulfill these necessary requirements. In particular, our calculations reproduce the experimentally available GT+ and GT- strength distributions and the nuclear halflives, and describe the nuclear spectra appropriately.Comment: 11 pages, 5 figure

    In memoriam Falco peregrinus

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    1885 finden sich dann gleich zwei Brüterwähnungen. Eine davon betrifft ein Gelege an den Externsteinen, das vier Eier enthielt. Nachdem eine Zerstörung durch Menschen verhindert werden konnte, wurde das Gelege von Mardern geraubt. In dieser ersten Erwähnung werden bereits die Punkte deutlich, die den Kampf um die Erhaltung des Wanderfalken in unserem Jahrhundert prägen: Zunächst muß der Falke vor den Nachstellungen seines ärgsten Feindes, des Menschen, geschützt werden. Aber selbst wenn das gelingt, treten oft noch natürliche Verluste ein. Diesen Kampf, eigentlich als Hauptthema für diesen Artikel gedacht, möchte ich im folgenden einerseits an der Geschichte der einzelnen Horste, andererseits aber auch an Beispielen aus Presseartikeln, die die Einstellung gegenüber unseren Greifen verdeutlichen, sowie an gerichtlichem Vorgehen gegen die illegal handelnden Greifvogelfeinde, darstellen. Das Material darüber konnte ich zum großen Teil der Akte HEINZ KUHLMANNs entnehmen, der den bei seinen vielfältigen und aufopfernden Bemühungen geführten Briefwechsel abheftete. Allgemeineres, zusammenfassendes Material stellte mir Herr Conrads zur Verfügung, Angaben über die Aussprengung des Horstes an der Velmerstot erhielt ich von Herrn Oberförster i.R. Klocke und Herrn Henschel, dem zuständigen Sachbearbeiter beim Regierungspräsidenten in Detmold. Ihnen und allen genannten Helfern bin ich für ihre bereitwillige Unterstützung sehr dankbar

    Chomosome Numbers in Fagus Grandi Folia and Quercus Virginina

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    The chromosomes have been counted in a number of species of Fagacere, both in Europe and America. The opportunity now arises to add to the rapidly growing list one more species of Quercus and one species of Fagus whose numbers have not until now been determined

    Fair Use Challenges in Academic and Research Libraries

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    Summarizes findings from a survey of librarians on the application of fair use in copyright practice to fulfill libraries' missions of teaching and learning support, scholarship support preservation, exhibition, and public outreach

    Four Thoughts on Four Themes

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