42,772 research outputs found

    Spatial variation of iron abundance in the high speed solar wind, 1972 to 1976

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    The Fe/H ratios in the peaks of high speed streams (HSS) during the decline of Solar Cycle 20 and the following minimum (October 1972-December 1976) were analyzed. The response of the 50-200 keV ion channel of the APL/JHU energetic particle experiment (EPE) on IMP-7 and 8 to solar wind iron ions at high solar wind speeds and Fe measurements were compared with solar wind H and He parameters from the Los Alamos National Laboratory (LANL) instruments on the same spacecraft. In general, the Fe distribution parameters (bulk velocity, flow direction, temperature) are found to be similar to the LANL He parameters. Although the average Fe/H ratio in many steady HSS peaks agrees within observational uncertainties with the nominal coronal ratio of 4.7 x 10(-5), abundance variations of a factor of up to 6 are obtained across a given coronal-hole associated HSS. Over the period 1973-1976, a steady decrease in the average quiet-time Fe/H ratio by a factor of about 4 is measured on both IMP-7 and 8

    Nutritional and cultural aspects of plant species selection for a controlled ecological life support system

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    The feasibility of using higher plants in a controlled ecological life support system is discussed. Aspects of this system considered important in the use of higher plants include: limited energy, space, and mass, and problems relating to cultivation and management of plants, food processing, the psychological impact of vegetarian diets, and plant propagation. A total of 115 higher plant species are compared based on 21 selection criteria

    Radiation-Driven Warping: The Origin of Warps and Precession in Accretion Disks

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    A geometrically thin, optically thick, warped accretion disk with a central source of luminosity is subject to non-axisymmetric forces due to radiation pressure; the resulting torque acts to modify the warp. In a recent paper, \cite{pri96} used a local analysis to show that initially planar accretion disks are unstable to warping driven by radiation torque. Here we extend this work with a global analysis of the stable and unstable modes. We confirm Pringle's conclusion that thin centrally-illuminated accretion disks are generically unstable to warping via this mechanism; we discuss the time-evolution and likely steady-state of such systems and show specifically that this mechanism can explain the warping of the disk of water masers in NGC 4258 and the 164-day precession period of the accretion disk in SS 433. Radiation-driven warping and precession provides a robust mechanism for producing warped, precessing accretion disks in active galactic nuclei and X-ray binary systems.Comment: 16 pages, latex, 3 figure

    Human factors analysis of workstation design: Earth Radiation Budget Satellite Mission Operations Room

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    A human factors analysis addressed three related yet distinct issues within the area of workstation design for the Earth Radiation Budget Satellite (ERBS) mission operation room (MOR). The first issue, physical layout of the MOR, received the most intensive effort. It involved the positioning of clusters of equipment within the physical dimensions of the ERBS MOR. The second issue for analysis was comprised of several environmental concerns, such as lighting, furniture, and heating and ventilation systems. The third issue was component arrangement, involving the physical arrangement of individual components within clusters of consoles, e.g., a communications panel

    Solar wind iron abundance variations at solar wind speeds up to 600 km s sup -1, 1972 to 1976

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    The Fe/H ratios in the peaks of high speed streams (HSS) were analyzed during the decline of Solar Cycle 20 and the following minimum (October 1972 to December 1976). The response of the 50 to 200 keV ion channel of the APL/JHU energetic particle experiment (EPE) on IMP-7 and 8 was utilized to solar wind iron ions at high solar wind speeds (V or = 600 km/sec). Fe measurements with solar wind H and He parameters were compared from the Los Alamos National Laboratory (LANL) instruments on the same spacecraft. In general, the Fe distribution parameters (bulk velocity, flow direction, temperature) are found to be similar to the LANL He parameters. Although the average Fe/H ration in many steady HSS peaks agrees within observational uncertainties with the nominal coronal ratio of 4.7 x 0.00001, abundance variations of a factor of up to 6 are obtained across a given coronal-hole associated HSS

    Preseason Functional Test Scores are Associated with Future Sports Injury in Female Collegiate Athletes

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    Brumitt, J, Heiderscheit, B, Manske, R, Niemuth, PE, Mattocks, A, and Rauh, MJ. Preseason functional test scores are associated with future sports injury in female collegiate athletes. J Strength Cond Res 32(6): 1692–1701, 2018—Recent prospective cohort studies have reported preseason functional performance test (FPT) measures and associations with future risk of injury; however, the findings associated with these studies have been equivocal. The purpose of this study was to determine the ability of a battery of FPTs as a preseason screening tool to identify female Division III (D III) collegiate athletes who may be at risk for a noncontact time-loss injury to the lower quadrant (LQ = low back and lower extremities). One hundred six female D III athletes were recruited for this study. Athletes performed 3 FPTs: standing long jump (SLJ), single-leg hop (SLH) for distance, and the lower extremity functional test (LEFT). Time-loss sport-related injuries were tracked during the season. Thirty-two (24 initial and 8 subsequent) time-loss LQ injuries were sustained during the study. Ten of the 24 initial injuries occurred at the thigh and knee. At-risk athletes with suboptimal FPT measures (SLJ #79% ht; (B) SLH #64% ht; LEFT $118 seconds) had significantly greater rates of initial (7.2 per 1,000 athletic exposures [AEs]) and total (7.6 per 1,000 AEs) time-loss thigh or knee injuries than the referent group (0.9 per 1,000 AEs; 1.0 per 1,000 AEs, respectively). At-risk athletes were 9 times more likely to experience a thigh or knee injury (odds ratio [OR] = 9.7, confidence interval [CI]: 2.3–39.9; p = 0.002) than athletes in the referent group. At-risk athletes with a history of LQ sports injury and lower off-season training habits had an 18-fold increased risk of a time-loss thigh or knee injury during the season (adjusted OR = 18.7, CI: 3.0–118.1; p = 0.002). This battery of FPTs appears useful as a tool for identifying female D III athletes at risk of an LQ injury, especially to the thigh or knee region

    Human factors aspects of control room design: Guidelines and annotated bibliography

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    A human factors analysis of the workstation design for the Earth Radiation Budget Satellite mission operation room is discussed. The relevance of anthropometry, design rules, environmental design goals, and the social-psychological environment are discussed

    Acoustic characterization of crack damage evolution in sandstone deformed under conventional and true triaxial loading

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    We thank the Associate Editor, Michelle Cooke, and the reviewers, Ze'ev Reches and Yves Guéguen, for useful comments which helped to improve the manuscript. We thank J.G. Van Munster for providing access to the true triaxial apparatus at KSEPL and for technical support during the experimental program. We thank R. Pricci for assistance with technical drawings of the apparatus. This work was partly funded by NERC award NE/N002938/1 and by a NERC Doctoral Studentship, which we gratefully acknowledge. Supporting data are included in a supporting information file; any additional data may be obtained from J.B. (e-mail: [email protected]).Peer reviewedPublisher PD
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