2,025 research outputs found

    On "the complete basis set limit" and plane-wave methods in first-principles simulations of water

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    Water structure, measured by the height of the first peak in oxygen-oxygen radial distributions, is converged with respect to plane-wave basis energy cutoffs for ab initio molecular dynamics simulations, confirming the reliability of plane-wave methods.Comment: 9 pages, 3 figure

    Measuring the repertoire of age-related behavioral changes in Drosophila melanogaster

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    Aging affects almost all aspects of an organism -- its morphology, its physiology, its behavior. Isolating which biological mechanisms are regulating these changes, however, has proven difficult, potentially due to our inability to characterize the full repertoire of an animal's behavior across the lifespan. Using data from fruit flies (D. melanogaster) we measure the full repertoire of behaviors as a function of age. We observe a sexually dimorphic pattern of changes in the behavioral repertoire during aging. Although the stereotypy of the behaviors and the complexity of the repertoire overall remains relatively unchanged, we find evidence that the observed alterations in behavior can be explained by changing the fly's overall energy budget, suggesting potential connections between metabolism, aging, and behavior

    Photoluminescence response of ion-implanted silicon

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    The photoluminescence intensity from ion-implanted silicon can be quenched by the radiation damage implicit in the implantation.Annealing is then required before the intensity of the luminescence from a defect center is approximately proportional to the concentration of that center. Data from positron annihilation and photoluminescence experiments establish that severe quenching of the luminescence occurs when the mean separation of the small vacancy clusters is less than ∼30 atomic spacings, and the authors map out where, in the annealing and implantation phase space, the luminescence intensity is expected to be approximately proportional to the concentration of the optical centers.This work was supported by EPSRC Grant No. GR/ R10820/01 and by the EU Co-ordination Action programme CADRES. One of the authors J.W.-L. acknowledges the support of the Australian Research Council

    Economic evaluation of an exercise-counselling intervention to enhance smoking cessation outcomes: The Fit2Quit trial

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    Background: In the Fit2Quit randomised controlled trial, insufficiently-active adult cigarette smokers who contacted Quitline for support to quit smoking were randomised to usual Quitline support or to also receive ≤10 face-to-face and telephone exercise-support sessions delivered by trained exercise facilitators over the 24-week trial. This paper aims to determine the cost-effectiveness of an exercise-counselling intervention added to Quitline compared to Quitline alone in the Fit2Quit trial. Methods: Within-trial and lifetime cost-effectiveness were assessed. A published Markov model was adapted, with smokers facing increased risks of lung cancer and cardiovascular disease. Results: Over 24 weeks, the incremental programme cost per participant in the intervention was NZ428(US428 (US289 or €226; purchasing power parity-adjusted [PPP]). The incremental cost-effectiveness ratio (ICER) for seven-day point prevalence measured at 24-week follow-up was NZ31,733(US31,733 (US21,432 or €16,737 PPP-adjusted) per smoker abstaining. However, for the 52% who adhered to the intervention (≥7 contacts), the ICER for point prevalence was NZ3,991(US/ce:para,695or€2,105PPP−adjusted).Inthisadherentsubgroup,theMarkovmodelestimated0.057and0.068discountedquality−adjustedlife−yeargainsoverthelifetimeof40−year−oldmales(ICER:NZ3,991 (US/ce:para,695 or €2,105 PPP-adjusted). In this adherent subgroup, the Markov model estimated 0.057 and 0.068 discounted quality-adjusted life-year gains over the lifetime of 40-year-old males (ICER: NZ4,431; US/ce:para,993 or €2,337 PPP-adjusted) and females (ICER: NZ/ce:para,909; USce:para,965 or €1,534 PPP-adjusted). Conclusions: The exercise-counselling intervention will only be cost-effective if adherence is a minimum of ≥7 intervention calls, which in turn leads to a sufficient number of quitters for health gains

    Decision support system in a patient-centered medical home

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    Lack of sufficient primary care to manage chronic diseases has been quoted as a major drawback of the healthcare system within the United States. Patient-Centered Medical Home is a care delivery model to transform how primary care is delivered. The information technology revolution has brought about several advancements and solutions for medicine and care delivery, and medical homes are no exception to this. However, it is only through a robust decision support system that these medical homes can in fact provide truly coordinated and patient-centered care. The paper describes preliminary work that has been completed at the University of Missouri Health System and next steps in achieving high quality care delivery through a decision support system implementation. Originally presented at the IEEE HealthCon Medial Home conference in June 2011

    Application of submodular optimization to single machine scheduling with controllable processing times subject to release dates and deadlines

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    In this paper, we study a scheduling problem on a single machine, provided that the jobs have individual release dates and deadlines, and the processing times are controllable. The objective is to find a feasible schedule that minimizes the total cost of reducing the processing times. We reformulate the problem in terms of maximizing a linear function over a submodular polyhedron intersected with a box. For the latter problem of submodular optimization, we develop a recursive decomposition algorithm and apply it to solving the single machine scheduling problem to achieve the best possible running time

    Medical students’ and doctors’ attitudes towards older patients and their care in hospital settings: a conceptualisation

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    Background: despite assertions in reports from governmental and charitable bodies that negative staff attitudes towards older patients may contribute to inequitable healthcare provision for older patients when compared with younger patients (those aged under 65 years), the research literature does not describe these attitudes in any detail. Objective: this study explored and conceptualised attitudes towards older patients using in-depth interviews. Methods: twenty-five semi-structured interviews with medical students and hospital-based doctors in a UK acute teaching hospital were conducted. Participants were asked about their beliefs, emotions and behavioural tendencies towards older patients, in line with the psychological literature on the definition of attitudes (affective, cognitive and behavioural information). Data were analysed thematically. Results: attitudes towards older patients and their care could be conceptualised under the headings: (i) beliefs about older patients; (ii) older patients’ unique needs and the skills required to care for them and (iii) emotions and satisfaction with caring for older patients. Conclusions: our findings outlined common beliefs and stereotypes specific to older patients, as opposed to older people in general. Older patients had unique needs concerning their healthcare. Participants typically described negative emotions about caring for older patients, but the sources of dissatisfaction largely related to the organisational setting and system in which the care is delivered to these patients. This study marks one of the first in-depth attempts to explore attitudes towards older patients in UK hospital settings
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