5,398 research outputs found

    Confirming the existence of π-allyl-palladium intermediates during the reaction of meta photocycloadducts with palladium(ii) compounds

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    The transient existence of π-allyl-palladium intermediates formed by the reaction of Pd(OAc)2 and anisole-derived meta photocycloadducts has been demonstrated using NMR techniques. The intermediates tended to be short-lived and underwent rapid reductive elimination of palladium metal to form allylic acetates, however this degradation process could be delayed by changing the reaction solvent from acetonitrile to chloroform

    Male Stress Urinary Incontinence: A Review of Surgical Treatment Options and Outcomes

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    Introduction and Objective. Iatrogenic male stress urinary incontinence (SUI) affects a percentage of men undergoing urologic procedures with a significant impact on quality of life. The treatment of male SUI has evolved significantly with multiple current options for treatment available. The current paper discusses preoperative evaluation of male SUI, available surgical options with reported outcomes, and postoperative complication management. Methods. A pubMed review of available literature was performed and summarized on articles reporting outcomes of placement of the artificial urinary sphincter (AUS) or male slings including the bone anchored sling (BAS), retrourethral transobturator sling (RTS), adjustable retropubic sling (ARS), and quadratic sling. Results. Reported rates of success (variably defined) for BAS, RTS, ARS, and AUS are 36–67%, 9–79%, 13–100%, and 59–91% respectively. Complications reported include infection, erosion, retention, explantation, and transient pain. Male slings are more commonly performed in cases of low-to-moderate SUI with decreasing success with higher degrees of preoperative incontinence. Conclusions. An increasing number of options continue to be developed for the management of male SUI. While the AUS remains the gold-standard therapy for SUI, male sling placement is a proven viable alternative therapy for low-to-moderate SUI

    Physical Activity, Obesity Status, and Blood Pressure in Preschool Children.

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    OBJECTIVE:To examine the combined effects of physical activity and weight status on blood pressure (BP) in preschool-aged children. STUDY DESIGN: The sample included 733 preschool-aged children (49% female). Physical activity was objectively assessed on 7 consecutive days by accelerometry. Children were categorized as sufficiently active if they met the recommendation of at least 60 minutes daily of moderate-to-vigorous physical activity (MVPA). Body mass index was used to categorize children as nonoverweight or overweight/obese, according to the International Obesity Task Force benchmarks. BP was measured using an automated BP monitor and categorized as elevated or normal using BP percentile-based cut-points for age, sex, and height. RESULTS: The prevalence of elevated systolic BP (SBP) and diastolic BP was 7.7% and 3.0%, respectively. The prevalence of overweight/obese was 32%, and about 15% of children did not accomplish the recommended 60 minutes of daily MVPA. After controlling for age and sex, overweight/obese children who did not meet the daily MVPA recommendation were 3 times more likely (OR 3.8; CI 1.6-8.6) to have elevated SBP than nonoverweight children who met the daily MVPA recommendation. CONCLUSIONS: Overweight or obese preschool-aged children with insufficient levels of MVPA are at significantly greater risk for elevated SBP than their nonoverweight and sufficiently active counterparts

    Framework for systematic evaluation of environmental ship design

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    CIVINS (Civilian Institutions) Thesis documentIncreasing awareness of environmental issues related to product design, development, use and disposal is requiring that designers account for environmental issues that had previously been neglected. In the military, these requirements are being added at the same time budgets are being cut and performance expectations are being increased. A successful design must be able to incorporate a strategy that will satisfy cost, performance, quality, maintenance and legal criteria while also optimizing environmental objectives. To meet these objectives, a formal design approach or framework that considers a life-cycle evaluation of environmental requirements, cost and performance criteria is needed. A framework is developed which considers both the engineering design requirements for the physical system, as well as the political constraints that often impact system design but are rarely formally considered. The New Attack Submarine program is used as a baseline for evaluating political constraints. Applications of the analytic hierarchy process and multiattribute utility functions are used to convey unspecified constraints to system design engineers. A case study of the approach recommended is developed using the air conditioning plants designed for the new attack submarine to eliminate the use of R-114 refrigeranthttp://archive.org/details/frameworkforsyst00trosCIVIN

    'Making it count': incentives, student effort and performance

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    This paper examines how incentives to participate in online assessments (quizzes) affect students’ effort and performance. Our identification strategy exploits within-student weekly variation in incentives to attempt online quizzes. We find tournament incentives and participation incentives to be ineffective in increasing quiz participation. In contrast, making the quiz counts towards the final grade substantially increases participation. We find no evidence of displacement of effort between weeks. Using a natural experiment which provides variation in assessment weighting of the quizzes between two cohorts, we find that affected students obtain better exam grades. We estimate the return to 10% assessment weighting to be around 0.27 of a standard deviation in the in-term exam grade. We find no evidence that assessment weighting has unintended consequences, i.e., that increased quiz effort: displaces effort over the year; reduces other forms of effort; or reduces (effort and thus) performance in other courses. Finally, assessment weighting induced effort increases most for students at and below median ability, resulting in a reduction of the grade gap by 17%
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