2,867 research outputs found

    Atomic Interactions in Precision Interferometry Using Bose-Einstein Condensates

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    We present theoretical tools for predicting and reducing the effects of atomic interactions in Bose-Einstein condensate (BEC) interferometry experiments. To address mean-field shifts during free propagation, we derive a robust scaling solution that reduces the three-dimensional Gross-Pitaevskii equation to a set of three simple differential equations valid for any interaction strength. To model the other common components of a BEC interferometer---condensate splitting, manipulation, and recombination---we generalize the slowly-varying envelope reduction, providing both analytic handles and dramatically improved simulations. Applying these tools to a BEC interferometer to measure the fine structure constant (Gupta, et al., 2002), we find agreement with the results of the original experiment and demonstrate that atomic interactions do not preclude measurement to better than part-per-billion accuracy, even for atomic species with relatively large scattering lengths. These tools help make BEC interferometry a viable choice for a broad class of precision measurements.Comment: 8 pages, 6 figures, revised based on reviewer comment

    Examining the Role of Authentic Leadership in Job Embeddedness and Turnover Intent

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    Hospital turnover has increased at alarming rates, particularly since the onset and in the aftermath of the COVID-19 pandemic. While traditional theories of turnover look at why employees leave, job embeddedness is both a theory and a framework that examines why people stay. Authentic leadership is a relational leadership style comprised of components of self-awareness, internalized moral perspective, relational transparency, balanced processing, and caring. This quantitative correlational research investigated the relationship of authentic leadership as mediator between job embeddedness and turnover intent, as well as the relationships between the five constructs of authentic leadership, to determine which, if any, caused an increase in job embeddedness and a decrease in turnover intent. Participants were nursing professionals recruited through social media. Participants completed a 43-question survey on job embeddedness, turnover intention, and perceptions of authentic leadership. Multiple regression analysis supported authentic leadership as a mediator between job embeddedness and turnover intent. Hierarchical multiple regression analyses indicated that all five constructs of authentic leadership were correlated with job embeddedness and turnover intent, although only self-awareness, internalized moral perspective, relational transparency, and caring caused increases in the variance of responses. This study adds to the literature on antecedents to job embeddedness and on the specific authentic leadership behaviors that cause greater embeddedness and reduce turnover

    Is there overutilisation of cataract surgery in England?

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    <b>Objectives:</b> Following a 3.7-fold increase in the rate of cataract surgery in the UK between 1989 and 2004, concern has been raised as to whether this has been accompanied by an excessive decline in the threshold such that some operations are inappropriate. The objective was to measure the impact of surgery on a representative sample of patients so as to determine whether or not overutilisation of surgery is occurring. <b>Design:</b> Prospective cohort assessed before and 3 months after surgery. <b>Setting:</b> Ten providers (four NHS hospitals, three NHS treatment centres, three independent sector treatment centres) from across England. <b>Participants:</b> 861 patients undergoing first eye (569) or second eye (292) cataract surgery provided preoperative data of whom 745 (87%) completed postoperative questionnaires. <b>Main outcome measures:</b> Patient-reported visual function (VF-14); general health status and quality of life (EQ5D); postoperative complications; overall view of the operation and its impact. <b>Results:</b> Overall, visual function improved (mean VF-14 score increased from 83.2 (SD 17.3) to 93.7 (SD 13.2)). Self-reported general health status deteriorated (20.3% fair or poor before surgery compared with 25% afterwards) which was reflected in the mean EQ5D score (0.82 vs 0.79; p = 0.003). At least one complication was reported by 66 (8.9%) patients, though this probably overestimated the true incidence. If the appropriateness of surgery is based on an increase in VF-14 score of 5.5 (that corresponds to patientsā€™ reporting being "a little better"), 30% of operations would be deemed inappropriate. If an increase of 12.2 (patientsā€™ reports of being "much better") is adopted, the proportion inappropriate is 49%. Using a different approach to determining a minimally important difference, the proportion inappropriate would be closer to 20%. Although visual function (VF-14) scores were unchanged or deteriorated in 25% of patients, 93.1% rated the results of the operation as "good," "very good" or "excellent," and 93.5% felt their eye problem was "better." This partly reflects inadequacies in the validity of the VF-14. <b>Conclusions:</b> Improvement in the provision of cataract surgery has been accompanied by a reduction in the visual function threshold. However, methodological difficulties in measuring the impact of cataract surgery on visual function and quality of life mean it is impossible to determine whether or not overutilisation of cataract surgery is occurring. N Black1, J Browne1, J van der Meulen1, L Jamieson2, L Copley2 and J Lewsey

    Candy elasticity: Halloween experiments on public political statements

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    This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.We conducted experiments during trick-or-treating on Halloween in a predominantly liberal neighborhood in the weeks preceding the 2008 and 2012 presidential elections. We decorated one side of a house porch with McCain material in 2008 (Romney material in 2012) and the other side with Obama material. Children were asked to choose a side, with half receiving the same candy on either side and half receiving more candy to go to the McCain/Romney side. This yields a ā€œcandy elasticityā€ of children's political support. Results vary by age: children ages nine and older were two to three times more likely to choose the Republican candidate when offered double candy for voting Republican compared to when offered equal candy, whereas children ages eight and under were particularly sticky and did not waver in their choice of candidate despite the offer of double candy
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