9,752 research outputs found

    Environmental test planning, selection and standardization aids available

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    Requirements for instrumentation, equipment, and methods to be used in conducting environmental tests on components intended for use by a wide variety of technical personnel of different educational backgrounds, experience, and interests is announced

    Results of a study of Mach number and Reynolds number effects on the crossflow drag characteristics of ogive cylinders and ogive-cylinder-frustum-cylinders at angles of attack to 30 degrees

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    An analysis was made to determine the effects of Mach number and Reynolds number on the local and total crossflow drag characteristics of ogive-cylinders and ogive-cylinder-frustum-cylinders at angles of the MSFC 14 in TWT and the LTV 4 ft HSWT, and pressure data obtained in the TWT, at Mach numbers 0.14, 0.8, 1.2, and 2.0, and a wide range of Reynolds numbers. Results indicate that the streamwise Reynolds number, VD/nusin alpha, is an important correlation parameter in the subcritical Reynolds number range at imcompressible speeds and that the crossflow Mach number correlates compressibility effects

    ‘Holding onto trauma?’ The prevalence and predictors of PTSD, anxiety, and depression in police officers working with victims of child abuse, rape, and sexual exploitation

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    Research into post-traumatic stress disorder (PTSD) and other common mental disorders (CMDs) in police officers is limited, with the majority of research predominately conducted outside the UK, and no study quantitively examining the role of social support in relation to the mental health of UK police officers working with victims of trauma. Therefore, this study aimed to examine the prevalence and predictors of PTSD and CMD in UK police officers who investigate rape, sexual exploitation, and child abuse, along with the potential protective role of social support. Participants were police officers (n = 353) within one police area, who completed self-report measures of PTSD, anxiety, depression, and social support. Results showed that 23% of officers had potentially clinical levels of PTSD, 26% had moderate to severe levels of anxiety and 35% had moderate to severe levels of depression. Female officers, those of constable rank, those working with victims of child abuse, and those with lowest levels of social support had poorer mental health. There was tentative evidence that social support statistically moderated the relationship between tenure and depression. These findings suggest the need for bespoke help for the sub-group of officers experiencing mental health problems and for further research into the potential protective role of social support

    Does wealth predict health among dogs in a protected area?

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    As the world's most ubiquitous carnivore, domestic dogs maintain unique proximity to human populations. Partly because dogs potentially serve as hosts of zoonotic diseases, determinants of canine health are increasingly the focus of interdisciplinary research. Emerging perspectives suggest that dogs' health may vary as a function of their owners' wealth and financial resources, a correlation that could potentially inform public health programs and conservation efforts. The objective of this study was to evaluate associations between household wealth and the health of domestic dogs (n = 208) among indigenous Mayangna communities in the Bosawás Biosphere Reserve, Nicaragua. The dogs were evaluated using serum biochemistry, complete blood count, and physical exam findings. Using these data, a principal components analysis (PCA) determined the presence of four "syndromes": 1) decreased body condition score (BCS) & hypoalbuminemia; 2) lymphocytosis & eosinophilia; 3) segmented neutrophilia; and 4) lymphadenopathy, tick infestation, & hyperglobulinemia. An inventory of possessions indexed household wealth. For all four syndromes, household wealth was a weak and uninformative predictor of the dogs' health. The few differences seen among dogs from households with different degrees of wealth likely reflect that nearly all dogs had marginal health and all households were relatively poor. Results from this study imply that owners' wealth may have diverse effects on canine health in rural settings

    Children's suggestibility in relation to their understanding about sources of knowledge

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    In the experiments reported here, children chose either to maintain their initial belief about an object's identity or to accept the experimenter's contradicting suggestion. Both 3– to 4–year–olds and 4– to 5–year–olds were good at accepting the suggestion only when the experimenter was better informed than they were (implicit source monitoring). They were less accurate at recalling both their own and the experimenter's information access (explicit recall of experience), though they performed well above chance. Children were least accurate at reporting whether their final belief was based on what they were told or on what they experienced directly (explicit source monitoring). Contrasting results emerged when children decided between contradictory suggestions from two differentially informed adults: Three– to 4–year–olds were more accurate at reporting the knowledge source of the adult they believed than at deciding which suggestion was reliable. Decision making in this observation task may require reflective understanding akin to that required for explicit source judgments when the child participates in the task

    The excited hadron spectrum in lattice QCD using a new method of estimating quark propagation

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    Progress in determining the spectrum of excited baryons and mesons in lattice QCD is described. Large sets of carefully-designed hadron operators have been studied and their effectiveness in facilitating the extraction of excited-state energies is demonstrated. A new method of stochastically estimating the low-lying effects of quark propagation is proposed which will allow reliable determinations of temporal correlations of single-hadron and multi-hadron operators.Comment: 5 pages, 4 figures, talk given at Hadron 2009, Tallahassee, Florida, December 1, 200

    Dipolar and scalar 3^3He and 129^{129}Xe frequency shifts in mm-sized cells

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    We describe a 3^{3}He-129^{129}Xe comagnetometer operating in stemless anodically bonded cells with a 6 mm3^3 volume and a 129^{129}Xe spin coherence time of 300 sec. We use a 87^{87}Rb pulse-train magnetometer with co-linear pump and probe beams to study the nuclear spin frequency shifts caused by spin polarization of 3^{3}He. By systematically varying the cell geometry in a batch cell fabrication process we can separately measure the cell shape dependent and independent frequency shifts. We find that a certain aspect ratio of the cylindrical cell can cancel the effects of 3^3He magnetization that limit the stability of vapor-cell comagnetometers. Using this control we also observe for the first time a scalar 3^{3}He-129^{129}Xe collisional frequency shift characterized by an enhancement factor κHeXe=−0.011±0.001\kappa_{\text{HeXe}} = -0.011\pm0.001.Comment: 4 pages, 4 figure
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