420 research outputs found

    Are radiopharmaceuticals safe? the case of FDG-18

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    5 p.Too many false-positive and adverse reactions related to radiopharmaceuticals take place every day in hospitals routine, but many are not reported or even sensed. Information concerning these kind of reactions is not abundant and nuclear medicine staff is usually overwhelmed by this information. As every healthcare intervention carries some risk of harm, clinical decision making needs to be supported by a systematic assessment of the balance of benefit to harm. A systematic review that considers only the favorable outcomes of an intervention, without also assessing the adverse effects and false positives reactions, can mislead by introducing a bias favoring the intervention that in the case o radiopharmaceuticals may to render a important factor related not even to the quality of the drug but even to the quality of the diagnosis. The results suggest a logical framework to make decisions in reviews that incorporate false positive and adverse reactions. Also, was explored situations where a comprehensive investigation of false positive reactions and adverse effects was warranted and suggest strategies to identify practicable and clinically useful outcomes. We concluded that there is the necessity to include and to recognize how strategic choices made in the review process determine what harms are found, and how the findings may affect clinical decisions. Researchers undertaking a systematic review that incorporates false positive reaction and adverse reactions must understand the rationale for the suggested methods and be able to implement them in their review. Beyond a world effort should be made to report as many cases of false positive and adverse reactions with radiopharmaceuticals as possible. Only if this is done a complete picture of false positive reactions with radiopharmaceuticals can be drawn

    A New Stellar Atmosphere Grid and Comparisons with HST/STIS Calspec Flux Distributions

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    The Space Telescope Imaging Spectrograph (STIS) has measured the spectral energy distributions (SEDs) for several stars of types O, B, A, F, and G. These absolute fluxes from the CALSPEC database are fit with a new spectral grid computed from the ATLAS-APOGEE ATLAS9 model atmosphere database using a chi-square minimization technique in four parameters. The quality of the fits are compared for complete LTE grids by Castelli & Kurucz (CK04) and our new comprehensive LTE grid (BOSZ). For the cooler stars, the fits with the MARCS LTE grid are also evaluated, while the hottest stars are also fit with the NLTE Lanz & Hubeny OB star grids. Unfortunately, these NLTE models do not transition smoothly in the infrared to agree with our new BOSZ LTE grid at the NLTE lower limit of Teff =15,000K. The new BOSZ grid is available via the Space Telescope Institute MAST archive and has a much finer sampled IR wavelength scale than CK04, which will facilitate the modeling of stars observed by the James Webb Space Telescope (JWST). Our result for the angular diameter of Sirius agrees with the ground- based interferometric value.Comment: 11 figure

    A guidance program for grades seven and eight, its operation and evaluation

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    Thesis (M.A.)--Boston University, 1945. This item was digitized by the Internet Archive

    The Growth & Migration of Jovian Planets in Evolving Protostellar Disks with Dead Zones

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    The growth of Jovian mass planets during migration in their protoplanetary disks is one of the most important problems that needs to be solved in light of observations of the exosolar planets. Studies of the migration of planets in standard gas disk models routinely show that migration is too fast to form Jovian planets, and that such migrating planetary cores generally plunge into the central stars in less than a Myr. In previous work, we have shown that a poorly ionized, less viscous region in a protoplanetary disk called a dead zone slows down the migration of fixed-mass planets. In this paper, we extend our numerical calculations to include dead zone evolution along with the disk, as well as planet formation via accretion of rocky and gaseous materials. Using our symplectic-integrator-gas dynamics code, we find that dead zones, even in evolving disks wherein migrating planets grow by accretion, still play a fundamental role in saving planetary systems. We demonstrate that Jovian planets form within 2.5 Myr for disks that are ten times more massive than a minimum mass solar nebula (MMSN) with an opacity reduction and without slowing down migration artificially. Our simulations indicate that protoplanetary disks with an initial mass comparable to the MMSN only produce Neptunian mass planets. We also find that planet migration does not help core accretion as much in the oligarchic planetesimal accretion scenario as it was expected in the runaway accretion scenario. Therefore we expect that an opacity reduction (or some other mechanisms) is needed to solve the formation timescale problem even for migrating protoplanets, as long as we consider the oligarchic growth. We also point out a possible role of a dead zone in explaining long-lived, strongly accreting gas disks.Comment: 16 pages, 15 figures, accepted for publication in Ap

    The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe

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    The preponderance of matter over antimatter in the early Universe, the dynamics of the supernova bursts that produced the heavy elements necessary for life and whether protons eventually decay --- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our Universe, its current state and its eventual fate. The Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed plan for a world-class experiment dedicated to addressing these questions. LBNE is conceived around three central components: (1) a new, high-intensity neutrino source generated from a megawatt-class proton accelerator at Fermi National Accelerator Laboratory, (2) a near neutrino detector just downstream of the source, and (3) a massive liquid argon time-projection chamber deployed as a far detector deep underground at the Sanford Underground Research Facility. This facility, located at the site of the former Homestake Mine in Lead, South Dakota, is approximately 1,300 km from the neutrino source at Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino charge-parity symmetry violation and mass ordering effects. This ambitious yet cost-effective design incorporates scalability and flexibility and can accommodate a variety of upgrades and contributions. With its exceptional combination of experimental configuration, technical capabilities, and potential for transformative discoveries, LBNE promises to be a vital facility for the field of particle physics worldwide, providing physicists from around the globe with opportunities to collaborate in a twenty to thirty year program of exciting science. In this document we provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess.Comment: Major update of previous version. This is the reference document for LBNE science program and current status. Chapters 1, 3, and 9 provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess. 288 pages, 116 figure

    Masculinity and HIV: Dimensions of Masculine Norms that Contribute to Men’s HIV-Related Sexual Behaviors

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    Numerous studies have documented a relationship between masculine norms and men’s HIV-related sexual behaviors, but intervening upon this relationship requires a nuanced understanding of the specific aspects of masculine norms that shape men’s sexual behaviors. We integrate theories on masculinities with empirical HIV research to identify specific dimensions of masculine norms that influence men’s HIV-related sexual behaviors. We identify three major dimensions of masculine norms that shape men’s sexual behavior: 1) uncontrollable male sex drive, 2) capacity to perform sexually, and 3) power over others. While the existing literature does help explain the relationship between masculine norms and men’s sexual behaviors several gaps remain including: a recognition of context-specific masculinities, an interrogation of the positive influences of masculinity, adoption of an intersectional approach, assessment of changes in norms and behaviors over time, and rigorous evaluations of gender-transformative approaches. Addressing these gaps in future research may optimize prevention efforts

    Sequential Therapy in Metastatic Renal Cell Carcinoma

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    The treatment of metastatic renal cell carcinoma (mRCC) has changed dramatically in the past decade. As the number of available agents, and related volume of research, has grown, it is increasingly complex to know how to optimally treat patients. The authors are practicing medical oncologists at the US Oncology Network, the largest community-based network of oncology providers in the country, and represent the leadership of the Network's Genitourinary Research Committee. We outline our thought process in approaching sequential therapy of mRCC and the use of real-world data to inform our approach. We also highlight the evolving literature that will impact practicing oncologists in the near future
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