459 research outputs found

    Report of the panel on earth structure and dynamics, section 6

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    The panel identified problems related to the dynamics of the core and mantle that should be addressed by NASA programs. They include investigating the geodynamo based on observations of the Earth's magnetic field, determining the rheology of the mantle from geodetic observations of post-glacial vertical motions and changes in the gravity field, and determining the coupling between plate motions and mantle flow from geodetic observations of plate deformation. Also emphasized is the importance of support for interdisciplinary research to combine various data sets with models which couple rheology, structure and dynamics

    Changing patterns in electroweak precision with new color-charged states: Oblique corrections and the WW boson mass

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    The recent measurement by the CDF Collaboration of the WW boson mass is in significant tension with the Standard Model expectation, showing a discrepancy of seven standard deviations. A larger value of mWm_W affects the global electroweak fit, particularly the best-fit values of the Peskin-Takeuchi parameters SS, TT (and perhaps UU) that measure oblique corrections from new physics. To meet this challenge, we propose some simple models capable of generating non-negative SS and TT, the latter of which faces the greatest upward pressure from the CDF measurement in scenarios with U=0U=0. Our models feature weak multiplets of scalars charged under SU(3)c×U(1)Y\mathrm{SU}(3)_{\text{c}} \times \mathrm{U}(1)_Y, which cannot attain nonzero vacuum expectation values but nevertheless produce e.g. T≠0T \neq 0 given some other mechanism to split the electrically charged and neutral scalars. We compute the oblique corrections in these models and identify ample parameter space supporting the CDF value of mWm_W.Comment: 27 pages, 4 figure

    Full superconducting gap in the candidate topological superconductor In1−x_{1-x}Pbx_xTe for x = 0.2

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    High-pressure synthesis techniques have allowed for the growth of samples on the indium-rich side of (Pb,In)Te, which have increased superconducting transition temperatures compared to lead-rich compounds. In this study we present measurements of the temperature dependence of the London penetration depth Δλ(T)\Delta \lambda(T) in the compound In0.8_{0.8}Pb0.2_{0.2}Te, which shows a bulk Tc,onsetT_{c,onset} of ∼4.75\sim4.75 K. The results indicate fully gapped BCS-like behavior, ruling out odd-parity, topologically nontrivial A2uA_{2u} pairing; however, odd-parity A1uA_{1u} pairing is still possible. Critical field values measured below 1 K and other superconducting parameters are also presented.Comment: 8 pages, 9 figure

    The development and validation of sexual health indicators of Canadians aged 16-24 years

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    Objectives: We developed and validated a set of self-administered, multidimensional indicators of sexual health among Canadians aged 16–24 years. Methods: This study used a mixed-method qualitative and quantitative approach to develop and validate indicators of sexual health. We used the four-stage Dillman method to identify, focus-test, pilot-test, and validate key metrics to measure sexual health. We collected quantitative data to validate the measures through a computer-assisted self-interviewing program among a purposive sample of 1,158 people aged 16–24 years recruited from four Canadian provinces. Results: The survey contained 75 items measuring five dimensions of sexual health: (1) physical, mental, emotional, and social well-being in relation to sexuality; (2) approach to sexuality; (3) sexual relationships; (4) sexual experiences; and (5) discrimination, coercion, and violence. Principal components analysis for composite measures found seven components with eigenvalues ≥ 1. The factor structure was stable across gender, age, size of area of residence, and language in which the survey was completed. Cronbach’s alpha coefficients ranged from 0.79 to 0.90. Indicators of condom use at last vaginal sex, protection self-efficacy, sexually transmitted infection/HIV testing self-efficacy, and sexual orientation also showed good construct validity. Conclusions: The indicators constituted a conceptually grounded survey that is easy for young adults to complete and contains valid, reliable, and psychometrically robust measures. The survey instrument provides a tool for future research to collect population-level data to measure and monitor trends in the sexual health of young people in Canada

    West Greenland Peregrine Falcon Survey, 1978

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    This brief report describes results of a survey project which has been banding West Greenland peregrines annually since 1972. Statistics on number of eyries, sex ratios, and number of young hatched per eyrie are given
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