8,108 research outputs found

    Measurement of the complex Faraday angle in thin-film metals and high temperature superconductors

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    A sensitive polarization modulation technique uses photoelastic modulation and hetrodyne detection to simultaneously measure the Faraday rotation and induced ellipticity in light transmitted by semiconducting and metallic samples. The frequencies measured are in the mid-infrared and correspond to the spectral lines of a CO2 laser. The measured temperature range is continuous and extends from 35 to 330K. Measured samples include GaAs and Si substrates, gold and copper films, and YBCO and BSCCO high temperature superconductors.Comment: 12 pages of text, 6 figures, fixed typos in formulas, added figur

    It takes a village to break up a match: a systemic analysis of formal youth mentoring relationship endings

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    BACKGROUND Although early closure of formal youth mentoring relationships has recently begun to receive some attention, more information about factors that contribute to premature endings, and how those factors interact, is needed so that empirically-based program practices can be developed and disseminated to prevent such endings and to ensure that youth reap the benefits mentoring can provide. OBJECTIVE This qualitative interview study applies a systemic model of youth mentoring relationships (Keller in J Prim Prev 26:169–188, 2005a) to the study of mentoring relationship endings in community-based mentoring matches to understand why these matches ended. METHOD Mentors, parents/guardians and program staff associated with 36 mentoring matches that had ended were interviewed about their experiences of these relationships and their understanding of why they had ended. Thematic analysis of the interview transcripts and mentoring program case notes for each match followed by systemic modeling of the relationships yielded three major findings. RESULTS A strong mentor–youth relationship is necessary but not sufficient for match longevity. The mentor–youth relationship, even when relatively strong, is unlikely to withstand disruptions in other relationships in the system. Agency contextual factors, such as program practices and policies and staffing patterns, have a critical role to play in sustaining mentoring matches, as they directly influence all of the relationships in the mentoring system. CONCLUSION These findings highlight the importance of considering not just the mentoring dyad but also the parent/guardian and program context when trying to prevent match closures. They also point to several program practices that may support longer mentoring relationships.Accepted manuscrip

    How should we interpret the two transport relaxation times in the cuprates ?

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    We observe that the appearance of two transport relaxation times in the various transport coefficients of cuprate metals may be understood in terms of scattering processes that discriminate between currents that are even, or odd under the charge conjugation operator. We develop a transport equation that illustrates these ideas and discuss its experimental and theoretical consequences.Comment: 19 pages, RevTeX with 8 postscript figures included. To appear in ``Non Fermi Liquid Physics'', J. Phys:Cond. Matt. (1997

    Agricultural Biotechnology: Legal Liability from Comparative and International Law Perspectives

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    Agricultural biotechnology has generated much discussion about possible legal liability for growing transgenic crops. In this article, the authors discuss how the legal regimes of four nations (Canada, Denmark, Germany, and the United States) would resolve various scenarios likely to raised liabilility issues. Building on this comparative discussion, the authors then discuss these likely scenarios as addressed in the on-going negotiations under the Cartagena Protocol on Biosafety Article 27 (Liability and Redress). The authors end the article with recommendations about an appropriate legal liabilty regime at the international level

    Electron spin relaxation in organic semiconductors probed through muSR

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    Muon spin spectroscopy and in particular the avoided level crossing technique is introduced, with the aim of showing it as a very sensitive local probe for electron spin relaxation in organic semiconductors. Avoided level crossing data on TMS-pentacene at different temperatures are presented, and they are analysed to extract the electron spin relaxation rate, that is shown to increase on increasing the temperature from 0.02 MHz to 0.33 MHz at 3 K and 300 K respectively.Comment: International Conference TSN2010 "Trends in spintronics and nanomagnetism

    Singular value decomposition applied to compact binary coalescence gravitational-wave signals

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    We investigate the application of the singular value decomposition to compact-binary, gravitational-wave data-analysis. We find that the truncated singular value decomposition reduces the number of filters required to analyze a given region of parameter space of compact binary coalescence waveforms by an order of magnitude with high reconstruction accuracy. We also compute an analytic expression for the expected signal-loss due to the singular value decomposition truncation.Comment: 4 figures, 6 page
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