3,385 research outputs found

    The Implications of Galaxy Formation Models for the TeV Observations of Current Detectors

    Full text link
    This paper represents a step toward constraining galaxy formation models via TeV gamm a ray observations. We use semi-analytic models of galaxy formation to predict a spectral distribution for the intergalactic infrared photon field, which in turn yields information about the absorption of TeV gamma rays from extra-galactic sources. By making predictions for integral flux observations at >200 GeV for several known EGRE T sources, we directly compare our models with current observational upper limits obtained by Whipple. In addition, our predictions may offer a guide to the observing programs for the current population of TeV gamma ray observatories.Comment: 6 pages, 11 figures, to appear in the proceedings of the 6th TeV Workshop at Snowbird, U

    Free Electron Density Measurements By IR Absorption In CdS

    Get PDF
    A contactless method for determining the spatial variation of the free carrier density in CdS is presented. The method involves the correlation of IR transmission with the free carrier density via the IR absorption coefficient. Preliminary measurements indicate a free electron density sensitivity of less than 5x1014 cm-3 and a spatial resolution which is limited only by the spot size of a CO2 (λ=10.6 μm) laser; this should be of the order of 100 μm. Experimental results indicate that the predominate scattering is due to impurity interaction at room temperature; this is indicative of the high degree of compensation in CdS

    Electrodeposition And Analysis Of Tin Selenide Films

    Get PDF
    Sn1±xSe films have been electrodeposited from aqueous solutions containing SnCl2 and ionically dissolved SeO2 or H2SeO3 and DMF solutions containing SnCl2 and molecularly dissolved selenium powder. The as-deposited films ranged from amorphous to polycrystalline and exhibited indirect or nondirect bandgaps from 0.85 to 0.95 eV. There was little difference between the appearance or material data of the films grown by the two techniques. Direct reaction between Sn++ and H2SeO3 or HSeO3_ in the aqueous solutions yielded a Se/SnxSe suspension/precipitate. Although this does not seem to have any serious effect on the deposition process, it does produce a decrease in the concentration and possibly a change in the composition of the ions in solution, as well as preventing in situ observation of the deposit and making the cleaning of the apparatus more difficult. Annealing slightly increased the Se/Sn ratio of microanalyzed layers near the substrate-deposit interface, and erased all x-ray diffraction structure. The bandgaps of the annealed films were shifted from approximately 0.9 eV to approximately 1.30 eV, consistent with the increased Se/Sn ratio. The films exhibited weak cathodic photocurents during deposition and photoconductance (ΔG/G⋍0.05) after deposition. The conductivity of Sample D (Sn0.91Se) was estimated to be on the order of 10 -4(Ω-cm)-1. Conductance-temperature plots indicated activation energies between 0.44 and 0.51 eV, probably indicative of deep acceptor levels and consistent with the p-type thermal voltage, millisecond photoconductance decay times, and the optical bandgaps. © 1986, The Electrochemical Society, Inc. All rights reserved

    Secondary HIV Infection and Mitigation in Cure-Related HIV Trials During Analytical Treatment Interruptions

    Get PDF
    To the Editor—We are writing to express concerns regarding facts reported in 2 recent Journal of Infectious Diseases articles pertaining to the ANRSLIGHT study, conducted in 18 clinical sites in France between September 2013 and May 2015. Initially, we were delighted to see the authors implemented several inclusion criteria that we believe were likely to ensure safety of participants during the analytical treatment interruption (ATI) that occurred during the trial, for example a nadir of CD4+ T-cell count of ≥300 cells/mm3 and an initial CD4+ T-cell count of ≥600/mm3. However, other aspects are dismaying, including the detailed identifying information about the index participant and partner. We fear it is possible to identify both persons from the elaborate medical and nonmedical history provided. After contacting the study Principal Investigator, Dr Lelièvre, through a European colleague, it appears there were no consents to disclose this information. Thus, we feel strongly that it was inappropriate to include such comprehensive, potentially identifying details

    Applying a research ethics review processes in rural practice-based research

    Get PDF
    Introduction: Partnering with rural primary care in practice-based research allows researchers access to a vital segment of the health care sector and a window into some of the most vulnerable, high-risk, high-need patient populations. The readiness for rural primary care to fully embrace research partnerships, however, is often tempered by ethical questions in conducting research in close-knit settings. This research provides practices with a refined decision support tool for evaluating the fit of research opportunities for their unique practices. Materials and Methods: A two-phase effort was conducted to glean insight from currently available literature on ethical considerations in practice-based research and augment this information by consulting with state-based subject matter experts. Qualitative data were gathered through semi-structured interviews with key stakeholders at each of the West Virginia medical schools. Results: The literature clearly acknowledges the need to ensure ethical standards in practice-based research – from the standpoints of the clinician and the researcher. The need to ensure comprehensive, culturally appropriate institutional review board approval is essential in developing and safeguarding participants. From discussions with subject matter experts, we find complementary guidance. However, tempering this sentiment is an overall caution of the unique role of rural primary care in representing and protecting the needs of the community. Five fundamental cautions regarding the conduct of practice-based research in rural settings are here identified, spanning the protection of individual patients, their communities, and clinicians. Discussion: Findings from this study can support and empower primary care clinicians and practices, especially those in rural and close-knit communities, to address essential considerations in practice-based research. Results allow for framing of a refined decision support tool for primary care practices and clinicians to use in evaluating the fit of research opportunities for their unique practices, instilling a sense of shared power in the research process by better equipping primary care to proactively engage in substantive dialogue with research partners

    Applying a research ethics review processes in rural practice-based research

    Get PDF
    Introduction: Partnering with rural primary care in practice-based research allows researchers access to a vital segment of the health care sector and a window into some of the most vulnerable, high-risk, high-need patient populations. The readiness for rural primary care to fully embrace research partnerships, however, is often tempered by ethical questions in conducting research in close-knit settings. This research provides practices with a refined decision support tool for evaluating the fit of research opportunities for their unique practices. Materials and Methods: A two-phase effort was conducted to glean insight from currently available literature on ethical considerations in practice-based research and augment this information by consulting with state-based subject matter experts. Qualitative data were gathered through semi-structured interviews with key stakeholders at each of the West Virginia medical schools. Results: The literature clearly acknowledges the need to ensure ethical standards in practice-based research – from the standpoints of the clinician and the researcher. The need to ensure comprehensive, culturally appropriate institutional review board approval is essential in developing and safeguarding participants. From discussions with subject matter experts, we find complementary guidance. However, tempering this sentiment is an overall caution of the unique role of rural primary care in representing and protecting the needs of the community. Five fundamental cautions regarding the conduct of practice-based research in rural settings are here identified, spanning the protection of individual patients, their communities, and clinicians. Discussion: Findings from this study can support and empower primary care clinicians and practices, especially those in rural and close-knit communities, to address essential considerations in practice-based research. Results allow for framing of a refined decision support tool for primary care practices and clinicians to use in evaluating the fit of research opportunities for their unique practices, instilling a sense of shared power in the research process by better equipping primary care to proactively engage in substantive dialogue with research partners
    • …
    corecore