5,804 research outputs found

    Suprathermal plasma observed on STS-3 Mission by plasma diagnostics package

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    Artificially produced electron beams were used extensively during the past decade as a means of probing the magnetosphere, and more recently as a means of actively controlling spacecraft potential. Experimentation in these areas has proven valuable, yet at times confusing, due to the interaction of the electron beam with the ambient plasma. The OSS-1/STS-3 Mission in March 1982 provided a unique opportunity to study beam-plasma interactions at an altitude of 240 km. On board for this mission was a Fast Pulse Electron Generator (FPEG). Measurements made by the Plasma Diagnostics Package (PDP) while extended on the Orbiter RMS show modifications of the ion and electron energy distributions during electron beam injection. Observations made by charged particle detectors are discussed and related to measurements of Orbiter potential. Several of the PDP instruments, the joint PDP/FPEG experiment, and observations made during electron beam injection are described

    How are the Children: Challenges and Opportunities in Improving Children\u27s Mental Health

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    The mental health of children is critical to their growth and development, but when their well-being is considered, discussions more often gravitate toward physical health, nutrition, education, parental influences, and living conditions. While these all represent important indicators of well-being, discussions also need to consider the importance of children’s mental and behavioral health. In this brief we explore the status of Southern Nevada’s children as it relates to mental health outcomes. Like physical health, good mental health is paramount to children’s overall functioning and maturation. Frequently when a child experiences mental and behavioral health challenges, signs and symptoms manifest in the home, community, and school. Using a secondary analysis of multiple primary datasets, including the National Survey of Children’s Health; Mental Illness Surveillance among Children in the United States; and the Mental Health National Outcome Measure, we analyze the mental health status of children in Southern Nevada. In doing so we provide an overview of services, access, and the implications of the Affordable Care Act. Outcomes are considered in relation to peer states as well as national indicators. This brief provides implications for strengthening the overall mental health service infrastructure, service delivery, and community capacity so that children will experience optimal mental health outcomes

    Time to Talk: The Mental Health of Adults in Nevada

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    About 11.3% of the adult population in Nevada report a past-year mental illness, with nearly 4% of them experiencing disorders serious enough to impair their functionality. Almost 13% of Nevada adults have substance abuse disorders, this is the second highest statewide substance abuse prevalence rate in the country; the District of Columbia is first at 14.7% of its population (SAMSHA, 2013). With most states (including Nevada) now increasing their mental health care budgets after years of spending cuts—between 2009 and 2012 there was a $4.35-billion drop in state mental health spending (Ollove, 2013)—pertinent questions center on needed treatment, research, and policy directions. The increased federal attention and support given to mental health care access has primed states across the nation like Nevada to move toward strengthening their service infrastructure. In this brief we first compare Nevada’s mental illness prevalence rates with those of peer states and national trends and then explore some strategies that could prove useful in positioning our state to address the mental health needs of its residents. We must elevate the discussion of mental health to the same level of seriousness given to the concern for physical health challenges as experienced by adults

    A microgravity isolation mount

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    The design and preliminary testing of a system for isolating microgravity sensitive payloads from spacecraft vibrational and impulsive disturbances is discussed. The Microgravity Isolation Mount (MGIM) concept consists of a platform which floats almost freely within a limited volume inside the spacecraft, but which is constrained to follow the spacecraft in the long term by means of very weak springs. The springs are realized magnetically and form part of a six degree of freedom active magnetic suspension system. The latter operates without any physical contact between the spacecraft and the platform itself. Power and data transfer is also performed by contactless means. Specifications are given for the expected level of input disturbances and the tolerable level of platform acceleration. The structural configuration of the mount is discussed and the design of the principal elements, i.e., actuators, sensors, control loops and power/data transfer devices are described. Finally, the construction of a hardware model that is being used to verify the predicted performance of the MGIM is described

    Influence of Humidity on Ultraviolet Injury

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    High humidity enhances the injurious effect of ultraviolet radiation. This was demonstrated in experiments in which hairless mice were irradiated with Westinghouse FS-40-T-12 sunlamps while maintained in an environmental chamber allowing controlled conditions of relative humidity and temperature. Hairless mice given 10 MED (minimal erythemal dose) while maintained at 80% relative humidity had markedly greater exfoliation, crusting, and erosion of skin than did mice maintained at 5% and 10% relative humidity. Animals kept at 50% humidity had damage intermediate to those kept at high and low humidity. These morphologic observations were confirmed histologically.Additionally, water immersion enhances ultraviolet injury. Animals immersed in water for 6 hr prior to irradiation with 3 MED had more damage than animals irradiated but not immersed. Similarly, albino rabbits irradiated with 300 nm radiation from a xenon arc grating monochrometer had lower erythemal energy requirements on that part of their skin that had been hydrated with wet packs compared to nonhydrated skin

    Neutrino Dimuon Production and the Strangeness Asymmetry of the Nucleon

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    We have performed the first global QCD analysis to include the CCFR and NuTeV dimuon data, which provide direct constraints on the strange and anti-strange parton distributions, s(x)s(x) and sˉ(x)\bar{s}(x). To explore the strangeness sector, we adopt a general parametrization of the non-perturbative s(x),sˉ(x)s(x), \bar{s}(x) functions satisfying basic QCD requirements. We find that the strangeness asymmetry, as represented by the momentum integral [S−]≡∫01x[s(x)−sˉ(x)]dx[S^{-}]\equiv \int_0^1 x [s(x)-\bar{s}(x)] dx, is sensitive to the dimuon data provided the theoretical QCD constraints are enforced. We use the Lagrange Multiplier method to probe the quality of the global fit as a function of [S−][S^-] and find −0.001<[S−]<0.004-0.001 < [S^-] < 0.004. Representative parton distribution sets spanning this range are given. Comparisons with previous work are made.Comment: 23 pages, 4 figures; expanded version for publicatio

    Robust Machine Learning Applied to Astronomical Datasets I: Star-Galaxy Classification of the SDSS DR3 Using Decision Trees

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    We provide classifications for all 143 million non-repeat photometric objects in the Third Data Release of the Sloan Digital Sky Survey (SDSS) using decision trees trained on 477,068 objects with SDSS spectroscopic data. We demonstrate that these star/galaxy classifications are expected to be reliable for approximately 22 million objects with r < ~20. The general machine learning environment Data-to-Knowledge and supercomputing resources enabled extensive investigation of the decision tree parameter space. This work presents the first public release of objects classified in this way for an entire SDSS data release. The objects are classified as either galaxy, star or nsng (neither star nor galaxy), with an associated probability for each class. To demonstrate how to effectively make use of these classifications, we perform several important tests. First, we detail selection criteria within the probability space defined by the three classes to extract samples of stars and galaxies to a given completeness and efficiency. Second, we investigate the efficacy of the classifications and the effect of extrapolating from the spectroscopic regime by performing blind tests on objects in the SDSS, 2dF Galaxy Redshift and 2dF QSO Redshift (2QZ) surveys. Given the photometric limits of our spectroscopic training data, we effectively begin to extrapolate past our star-galaxy training set at r ~ 18. By comparing the number counts of our training sample with the classified sources, however, we find that our efficiencies appear to remain robust to r ~ 20. As a result, we expect our classifications to be accurate for 900,000 galaxies and 6.7 million stars, and remain robust via extrapolation for a total of 8.0 million galaxies and 13.9 million stars. [Abridged]Comment: 27 pages, 12 figures, to be published in ApJ, uses emulateapj.cl
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