1,463 research outputs found

    Sterilizable wide angle gas bearing gyro FGG334S Quarterly progress report, Jul. 1 - Oct. 1, 1967

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    Vibration and shock testing for spin motors for sterilizable wide angle gas bearing gyr

    Risk And Protective Factors Related to Female/Male Use Of Alcohol In Grades 7-12

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    The purpose of this study was to investigate risk and protective factors related to the use of alcohol during a 30-day time frame for 7th-12 th grade females/males. The comparisons were male non-users to male users, female non-users to female users, and male users to female users. Data were collected from the spring 2003 Grand Forks (North Dakota) Public Schools Youth Risk and Protective Factor Survey (YRPFS). The study was conducted with 666 students: 375 were in grades 7-9 and 291 were in grades 10-12. There were 340 females and 326 males. MANOVA was used to investigate the differences between the comparison groups. The level of significance was set at .01. There were significant differences found at all grade levels for male and female non-users and users of alcohol. Non-users were more likely to have protective factor influences (e.g., personal perception, parent perception, and positive beliefs). Users were more likely to have risk factor influences (e.g., other drug use; friend\u27s influence; school drug use; alcohol, tobacco, and other drug (ATOD) school availability; and ATOD community availability). There were slight variations between male and female users; males were higher on risk factors, other drug use, and ATOD community availability. There were no significant differences found within any of the comparison groups on 5 of the 14 factors. These were personal support, parent/school involvement, parental relationships, home violence, and school safety. In conclusion, this study found there were specific risk and protective factors that influenced the non-use and use of alcohol by males and females at all grade levels. There were very few differences for male and female users: males were higher on only two of the factors. This study provided significant findings that can be used to develop strategies to promote protective factors and reduce risk factors. Some of the specific recommendations included the need to use these findings and further research on risk/protective factors as a guide to reduce/eliminate the use of alcohol by adolescents. These results must be shared with youth, parents, schools, and communities to develop a collaborative action plan that will promote healthy youth development

    Neurologic Equine Herpes Virus (EHV-1)

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    This publication provides background information and describes clinical signs, diagnosis, treatment, vaccination and preventive measures

    The pure non-collisional Blue Straggler population in the giant stellar system omega Centauri

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    We have used high spatial resolution data from the Hubble Space Telescope and wide-field ground-based observations to search for blue straggler stars (BSS) over the entire radial extent of the large stellar system omega Centauri. We have detected the largest population of BSS ever observed in any stellar system. Even though the sample is restricted to the brightest portion of the BSS sequence, more than 300 candidates have been identified. BSS are thought to be produced by the evolution of binary systems (either formed by stellar collisions or mass exchange in binary stars). Since systems like Galactic globular clusters (GGC) and omega Cen evolve dynamically on time-scales significantly shorter than their ages, binaries should have settled toward the center, showing a more concentrated radial distribution than the ordinary, less massive single stars. Indeed, in all GGCs which have been surveyed for BSS, the BSS distribution is peaked at the center. Conversely, in omega Cen we find that the BSS share the same radial distribution as the adopted reference populations. This is the cleanest evidence ever found that such a stellar system is not fully relaxed even in the central region. We further argue that the absence of central concentration in the BSS distribution rules out a collisional origin. Thus, the omega Cen BSS are the purest and largest population of non-collisional BSS ever observed. Our results allow the first empirical quantitative estimate of the production rate of BSS via this channel. BSS in omega Cen may represent the best local template for modeling the BSS populations in distant galaxies where they cannot be individually observed.Comment: 21 pages, 6 figures, accepted for publication by Ap

    Regolith production and transport at the Susquehanna Shale Hills Critical Zone Observatory, Part 2: Insights from meteoric 10Be

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    Regolith-mantled hillslopes are ubiquitous features of most temperate landscapes, and their morphology reflects the climatically, biologically, and tectonically mediated interplay between regolith production and downslope transport. Despite intensive research, few studies have quantified both of these mass fluxes in the same field site. Here we present an analysis of 87 meteoric 10Be measurements from regolith and bedrock within the Susquehanna Shale Hills Critical Zone Observatory (SSHO), in central Pennsylvania. Meteoric 10Be concentrations in bulk regolith samples (n=73) decrease with regolith depth. Comparison of hillslope meteoric 10Be inventories with analyses of rock chip samples (n=14) from a 24 m bedrock core confirms that >80% of the total inventory is retained in the regolith. The systematic downslope increase of meteoric 10Be inventories observed at SSHO is consistent with 10Be accumulation in slowly creeping regolith (∼ 0.2 cm yr-1). Regolith flux inferred from meteoric 10Be varies linearly with topographic gradient (determined from high-resolution light detection and ranging-based topography) along the upper portions of hillslopes at SSHO. However, regolith flux appears to depend on the product of gradient and regolith depth where regolith is thick, near the base of hillslopes. Meteoric 10Be inventories at the north and south ridgetops indicate minimum regolith residence times of 10.5 ± 3.7 and 9.1 ± 2.9 ky, respectively, similar to residence times inferred from U-series isotopes in Ma et al. (2013). The combination of our results with U-series-derived regolith production rates implies that regolith production and erosion rates are similar to within a factor of two on SSHO hillcrests. ©2013. American Geophysical Union. All Rights Reserved

    A Superwind from Early Post-Red Giant Stars?

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    We suggest that the gap observed at 20,000 K in the horizontal branches of several Galactic globular clusters is caused by a small amount of extra mass loss which occurs when stars start to "peel off" the red giant branch (RGB), i.e., when their effective temperature starts to increase, even though they may still be on the RGB. We show that the envelope structure of RGB stars which start to peel off is similar to that of late asymptotic giant branch stars known to have a super-wind phase. An analogous super-wind in the RGB peel-off stars could easily lead to the observed gap in the distribution of the hottest HB stars.Comment: 9 pages; Accepted by ApJ Letters; Available also at http://www.astro.puc.cl/~mcatelan

    Software Testing and Verification in Climate Model Development

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    Over the past 30 years most climate models have grown from relatively simple representations of a few atmospheric processes to a complex multi-disciplinary system. Computer infrastructure over that period has gone from punch card mainframes to modem parallel clusters. Model implementations have become complex, brittle, and increasingly difficult to extend and maintain. Existing verification processes for model implementations rely almost exclusively upon some combination of detailed analysis of output from full climate simulations and system-level regression tests. In additional to being quite costly in terms of developer time and computing resources, these testing methodologies are limited in terms of the types of defects that can be detected, isolated and diagnosed. Mitigating these weaknesses of coarse-grained testing with finer-grained "unit" tests has been perceived as cumbersome and counter-productive. In the commercial software sector, recent advances in tools and methodology have led to a renaissance for systematic fine-grained testing. We discuss the availability of analogous tools for scientific software and examine benefits that similar testing methodologies could bring to climate modeling software. We describe the unique challenges faced when testing complex numerical algorithms and suggest techniques to minimize and/or eliminate the difficulties
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