9,813 research outputs found

    Science leadership for tomorrow: The role of schools of public affairs and universities in meeting needs of public science agencies

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    Recommendations and requirements for the preparation of personnel with some scientific or technological background to enter fields of public policy and administration are reported. University efforts to provide science administration graduate programs are outlined and increased cooperation between government and university resources is outlined

    Temporal patterns of nutrition dependence in secondary sexual traits and their varying impacts on male mating success

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    Variation in the quantity of nutrients ingested over an individual’s lifetime is likely to differentially affect distinct male secondary sexual traits and courtship signals, potentially providing females with information about a male’s past and present foraging history. We hypothesize that female choice is thus influenced by a male’s lifetime foraging history. To test this, we manipulated the quantity of nutrients (i.e. prey items) available to male wolf spiders, Schizocosa stridulans, using a fully crossed 2 × 2 design with low versus high prey quantity across juvenile and adult life stages, and assessed the impact of these diet treatments on male foreleg pigmentation, courtship rate and mating success. We found foreleg pigmentation to be dependent upon both juvenile and adult diet, with increased nutrition dependence of pigmented versus unpigmented leg segments. Despite this, the degree of foreleg pigmentation did not predict mating success. In contrast, courtship rate was not nutrient dependent, yet strongly predicted mating success. Finally, we found a significant interaction between juvenile diet, adult diet and courtship rate on mating success. Males that experienced a diet switch (low juvenile to high adult, LH; high juvenile to low adult, HL) exhibited no relationship between courtship rate and mating success, while those that experienced a consistent diet (LL; HH) showed increased mating success with increased courtship rates. Our results suggest that nutrition dependence of secondary sexual traits is not necessarily a predictor of their role in mating success and that female mate choice is the result of complex interactions between multiple male traits

    The Role of Canids in Ritual and Domestic Contexts: New Ancient DNA Insights from Complex Hunter-Gatherer Sites in Prehistoric Central California

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    This study explores the interrelationship between the genus Canis and hunter–gatherers through a case study of prehistoric Native Americans in the San Francisco Bay-Sacramento Delta area. A distinctive aspect of the region\u27s prehistoric record is the interment of canids, variously classified as coyotes, dogs, and wolves. Since these species are difficult to distinguish based solely on morphology, ancient DNA analysis was employed to distinguish species. The DNA study results, the first on canids from archaeological sites in California, are entirely represented by domesticated dogs (including both interments and disarticulated samples from midden deposits). These results, buttressed by stable isotope analyses, provide new insight into the complex interrelationship between humans and canids in both ritual and prosaic contexts, and reveal a more prominent role for dogs than previously envisioned

    The McGill score as a screening test for obstructive sleep disordered breathing in children with co-morbidities

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    Background: The McGill score is used to stratify severity of oximetry in children referred for investigation of obstructive sleep apnoea (OSA) to identify those with more severe disease and prioritize treatment. We hypothesized that its Positive predictive value (PPV) and Negative predictive value (NPV) in detecting OSA differs significantly between children with medical conditions and otherwise healthy children. / Methods: We performed a two-year retrospective analysis of children referred for investigation of OSA who underwent a cardiorespiratory (CR) polygraphy study. McGill score was calculated from the oximetry trace blinded to polygraphy results. We looked at 2 definitions of OSA: Obstructive Apnoea Hypopnoea Index (oAHI) ≥1 and ≥5. McGill sensitivity, specificity, PPV and NPV were calculated. McGill score=1 was considered normal or inconclusive, >1 abnormal. / Results: We studied 312 children, 190 males (61%), median age 4.5 (2.4-7.9) years. 129 were otherwise healthy and 183 had associated medical conditions. The PPV of the McGill score was significantly lower in children with medical conditions than otherwise healthy children. The NPV was similar in both groups of children. / Conclusions: The higher number of false positives in children with medical conditions may be due to non-obstructive causes such as central apnoeas. Children with underlying lung disease are also more likely to desaturate following a brief apnoea or hypopnoea. Children with co-morbidities who have an abnormal McGill score should not be assumed to have OSA and need more detailed sleep studies to determine the reason for the oxygen desaturations

    NEAR-SURFACE EFFECTS IN MODELLING OSCILLATIONS OF ETA BOO

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    Following the report of solar-like oscillations in the G0 V star eta Boo (Kjeldsen et al. 1995, AJ 109, 1313), a first attempt to model the observed frequencies was made by Christensen-Dalsgaard et al. (1995, ApJ Letters, in press). This attempt succeeded in reproducing the observed frequency separations, although there remained a difference of about 10 microHz between observed and computed frequencies. In those models, the near-surface region of the star was treated rather crudely. Here we consider more sophisticated models that include non-local mixing-length theory, turbulent pressure and nonadiabatic oscillations.Comment: uuencoded and compressed Postscript (2 pages, including figure); To appear in Proceedings of IAU Colloquium 155, "Astrophysical Applications of Stellar Pulsation", Cape Town, South Afric

    Effect of statins on venous thromboembolic events: a meta-analysis of published and unpublished evidence from randomised controlled trials

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    Background - It has been suggested that statins substantially reduce the risk of venous thromboembolic events. We sought to test this hypothesis by performing a meta-analysis of both published and unpublished results from randomised trials of statins. Methods and Findings - We searched MEDLINE, EMBASE, and Cochrane CENTRAL up to March 2012 for randomised controlled trials comparing statin with no statin, or comparing high dose versus standard dose statin, with 100 or more randomised participants and at least 6 months' follow-up. Investigators were contacted for unpublished information about venous thromboembolic events during follow-up. Twenty-two trials of statin versus control (105,759 participants) and seven trials of an intensive versus a standard dose statin regimen (40,594 participants) were included. In trials of statin versus control, allocation to statin therapy did not significantly reduce the risk of venous thromboembolic events (465 [0.9%] statin versus 521 [1.0%] control, odds ratio [OR] = 0.89, 95% CI 0.78–1.01, p = 0.08) with no evidence of heterogeneity between effects on deep vein thrombosis (266 versus 311, OR 0.85, 95% CI 0.72–1.01) and effects on pulmonary embolism (205 versus 222, OR 0.92, 95% CI 0.76–1.12). Exclusion of the trial result that provided the motivation for our meta-analysis (JUPITER) had little impact on the findings for venous thromboembolic events (431 [0.9%] versus 461 [1.0%], OR = 0.93 [95% CI 0.82–1.07], p = 0.32 among the other 21 trials). There was no evidence that higher dose statin therapy reduced the risk of venous thromboembolic events compared with standard dose statin therapy (198 [1.0%] versus 202 [1.0%], OR = 0.98, 95% CI 0.80–1.20, p = 0.87). Risk of bias overall was small but a certain degree of effect underestimation due to random error cannot be ruled out. Please see later in the article for the Editors' Summary. Conclusions - The findings from this meta-analysis do not support the previous suggestion of a large protective effect of statins (or higher dose statins) on venous thromboembolic events. However, a more moderate reduction in risk up to about one-fifth cannot be ruled out
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