3,223 research outputs found

    Log-dimensional spectral properties of one-dimensional quasicrystals

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    We consider discrete one-dimensional Schr\"odinger operators on the whole line and establish a criterion for continuity of spectral measures with respect to log\log-Hausdorff measures. We apply this result to operators with Sturmian potentials and thereby prove logarithmic quantum dynamical lower bounds for all coupling constants and almost all rotation numbers, uniformly in the phase.Comment: 7 page

    Occupational Health and Safety in the Expanding Economies: Severe Challenges and the Need for Action Through Education and Training

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    The occupational health and safety (OHS) situation in expanding economies is not encouraging. As was dramatically demonstrated by the recent epidemic of Ebola virus disease in West Africa in which many health care workers lost their lives, the majority of low- and middle-income countries (LMICs) are currently not able to adequately prevent occupational diseases. Every year occupational health services in these countries fall farther behind those in high-income countries (HICs). The widening gap in occupational health services between the global north and the global south parallels the increasing gap between high- and low-income countries in national wealth, a gap apparently caused by unbalanced development of globalized markets

    Effect of Death Jumps and Back Squats on Eliciting Postactivation Potentiation for a 40-meter Sprint

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    Please refer to the pdf version of the abstract located adjacent to the title

    Implementing a 48 h EWTD-compliant rota for junior doctors in the UK does not compromise patients’ safety : assessor-blind pilot comparison

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    Background: There are currently no field data about the effect of implementing European Working Time Directive (EWTD)-compliant rotas in a medical setting. Surveys of doctors’ subjective opinions on shift work have not provided reliable objective data with which to evaluate its efficacy. Aim: We therefore studied the effects on patient's safety and doctors’ work-sleep patterns of implementing an EWTD-compliant 48 h work week in a single-blind intervention study carried out over a 12-week period at the University Hospitals Coventry & Warwickshire NHS Trust. We hypothesized that medical error rates would be reduced following the new rota. Methods: Nineteen junior doctors, nine studied while working an intervention schedule of <48 h per week and 10 studied while working traditional weeks of <56 h scheduled hours in medical wards. Work hours and sleep duration were recorded daily. Rate of medical errors (per 1000 patient-days), identified using an established active surveillance methodology, were compared for the Intervention and Traditional wards. Two senior physicians blinded to rota independently rated all suspected errors. Results: Average scheduled work hours were significantly lower on the intervention schedule [43.2 (SD 7.7) (range 26.0–60.0) vs. 52.4 (11.2) (30.0–77.0) h/week; P < 0.001], and there was a non-significant trend for increased total sleep time per day [7.26 (0.36) vs. 6.75 (0.40) h; P = 0.095]. During a total of 4782 patient-days involving 481 admissions, 32.7% fewer total medical errors occurred during the intervention than during the traditional rota (27.6 vs. 41.0 per 1000 patient-days, P = 0.006), including 82.6% fewer intercepted potential adverse events (1.2 vs. 6.9 per 1000 patient-days, P = 0.002) and 31.4% fewer non-intercepted potential adverse events (16.6 vs. 24.2 per 1000 patient-days, P = 0.067). Doctors reported worse educational opportunities on the intervention rota. Conclusions: Whilst concerns remain regarding reduced educational opportunities, our study supports the hypothesis that a 48 h work week coupled with targeted efforts to improve sleep hygiene improves patient safety

    Environment and Obesity in the National Children\u27s Study

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    Objective: In this review we describe the approach taken by the National Children’s Study (NCS), a 21-year prospective study of 100,000 American children, to understanding the role of environmental factors in the development of obesity. Data sources and extraction: We review the literature with regard to the two core hypotheses in the NCS that relate to environmental origins of obesity and describe strategies that will be used to test each hypothesis. Data synthesis: Although it is clear that obesity in an individual results from an imbalance between energy intake and expenditure, control of the obesity epidemic will require understanding of factors in the modern built environment and chemical exposures that may have the capacity to disrupt the link between energy intake and expenditure. The NCS is the largest prospective birth cohort study ever undertaken in the United States that is explicitly designed to seek information on the environmental causes of pediatric disease. Conclusions: Through its embrace of the life-course approach to epidemiology, the NCS will be able to study the origins of obesity from preconception through late adolescence, including factors ranging from genetic inheritance to individual behaviors to the social, built, and natural environment and chemical exposures. It will have sufficient statistical power to examine interactions among these multiple influences, including gene–environment and gene–obesity interactions. A major secondary benefit will derive from the banking of specimens for future analysis

    The effectiveness of back squats and depth jumps on eliciting postactivation potentiation

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    PURPOSE: Data show that heavy preload stimuli preceding a sprint can improve performance by eliciting postactivation potentiation (PAP), an increased intramuscular sensitivity to calcium that enhances cross-bridge cycling, thereby acutely enhancing force production and strength. The aim of this study was to compare depth jumps (DJ) to back squats (BS) as a means to elicit PAP in college aged female rowers. METHODS: Twenty Division III collegiate female athletes, whose mean ± SD for age, height, weight, and VO2 Max were, respectively, 18.9 ± 0.9y, 1.5 ± 0.05m, 60.7 ± 21.4kg and 42.8 ± 4.44 ml.kg-1.min-1, completed a 40m sprint timed at 10m, 20m, and 40m with an electronic timing system. Subjects were randomly divided into either the DJ or BS group. Subsequently, their one repetition maximum (1 RM) for the BS or DJ was measured. One week later, subjects completed a 40m sprint, and then three repetitions at 90% of their 1RM for BS or three DJ; after 7 min of active rest, they completed a second 40m sprint. A dynamic warm-up and active cool down preceded and followed each testing session. Data were analyzed with three 2x2 repeated measures ANOVA with post hoc t-test performed where significance was found. RESULTS: Both conditions increased sprint time at 40m with DJ being significantly slower while BS only trended toward significance; DJ and BS 20m sprint time was also slower although not significantly. CONCLUSION: The data show that three repetitions at 90% of 1RM for BS or three DJ did not elicit PAP in female college rowers. These findings may be related to sex, load, training incompatibility, or sprinting proficiency in this subject population

    Stock Returns and the Franchise Value

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    An accurate predictive model of a firm’s future performance has been long sought after in the finance field. This study examines the relationship of a firm’s franchise value, using the Franchise Factor, to its Price-to-Earnings ratio as one model of performance. Using the firms in the S&P 1,500 as the data sample, this study also examines the effects of market value along with the franchise value to price-to-earnings ratio. The results show that the franchise value to price-to-earnings ratio, even when controlling for the firm’s market value, was in fact predictive of individual companies’ stock returns between 2000 and 2009
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