1,492 research outputs found

    Effects of Electron Correlations on Hofstadter Spectrum

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    By allowing interactions between electrons, a new Harper's equation is derived to examine the effects of electron correlations on the Hofstadter energy spectra. It is shown that the structure of the Hofstadter butterfly ofr the system of correlated electrons is modified only in the band gaps and the band widths, but not in the characteristics of self-similarity and the Cantor set.Comment: 13 pages, 5 Postscript figure

    Thematic Research network for emergency and UnScheduled Treatment (TRUST): scoping the potential

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    <p>Abstract</p> <p>Background</p> <p>To identify the benefits of a network in emergency and unscheduled care research, a six week scoping study was undertaken. Objectives were to: draw together stakeholders; identify and prioritise research topics; identify sites for recruitment to studies; and agree a research strategy for a network.</p> <p>Methods</p> <p>A workshop was held to discuss and agree a research strategy based on results from four activities: visits to established research centres in emergency and unscheduled care; a literature overview; interviews with stakeholders in a GP out-of-hours service; and an exploration of the potential for routine data to support research in emergency care.</p> <p>Results</p> <p>Participants attended the workshop from user groups, primary care, the ambulance service, social care, the national telephone based health helpline, the Welsh Assembly Government and the academic sector. Site visits identified opportunities for collaboration. Gaps in knowledge were identified concerning the effectiveness of alternative models of emergency care delivery. Interview data highlighted a lack of evidence related to the quality of out-of-hours provision of primary care. The All Wales Injury Surveillance System (AWISS) was found to offer the potential to use routine data to support quantitative studies in emergency care. Three key issues emerged across all activities: working across boundaries; patient involvement; and triage.</p> <p>Conclusion</p> <p>The study included views from patient, provider, policy and academic perspectives and built the case for a research network in emergency care. Now funded, TRUST (Thematic Research network for emergency and UnScheduled Treatment) will allow the development of research proposals, building of research teams and recruitment of sites and patients both in Wales and across the UK. It aims to address the imbalance between investment and research in this area and help support provision of 'the right care to the right people at the right time'.</p

    Composing Programming Languages by Combining Action-Semantics Modules

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    This article demonstrates a method for composing a programming language by combining action-semantics modules. Each module is defined separately, and then a programming-language module is defined by combining existing modules. This method enables the language designer to gradually develop a language by defining, selecting and combining suitable modules. The resulting modular structure is substantially different from that previously employed in action-semantic descriptions. It also discusses how to resolve the conflicts that may arise when combining modules, and indicates some advantages that action semantics has over other approaches in this respect

    Nonequilibrium effects due to charge fluctuations in intrinsic Josephson systems

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    Nonequilibrium effects in layered superconductors forming a stack of intrinsic Josephson junctions are investigated. We discuss two basic nonequilibrium effects caused by charge fluctuations on the superconducting layers: a) the shift of the chemical potential of the condensate and b) charge imbalance of quasi-particles, and study their influence on IV-curves and the position of Shapiro steps.Comment: 17 pages, 2 figures, revised version slightly shortene

    Safety and acceptability of tubal ligation procedures performed by trained clinical officers in rural Uganda.

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    OBJECTIVE: To assess safety associated with tubal ligation performed by trained clinical officers (COs) in rural Uganda. METHODS: Between March and June 2012, 518 women in 4 regions of Uganda were recruited into a prospective cohort study and followed at days 3, 7, and 45 after undergoing tubal ligation performed by a trained CO. Intraoperative and postoperative adverse events (minor, moderate, or major), and acceptability were assessed. RESULTS: Mean age was 36 years (range, 20-49 years) and mean number of living children was 6.7 (range, 0-15). The overall rate of major adverse events was 1.5%: 0.4% intraoperatively; 1.9% at day 3; and 0.2% at day 7. The majority of women who underwent tubal ligation reported a good/very good experience at the facility (range, 94%-99%) and would recommend the health services to a friend (range, 93%-98%). CONCLUSION: In the present study, task sharing of tubal ligation to trained COs in private facilities was safe. Women reported high levels of satisfaction with the procedure. Training COs could be an effective strategy for expanding family-planning services to rural Uganda

    DISTINGUISHING NATIVE AND PLANTATION-GROWN MAHOGANY (SWIETENIA MACROPHYLLA) TIMBER USING CHROMATOGRAPHY AND HIGH-RESOLUTION QUADRUPOLE TIME-OF-FLIGHT MASS SPECTROMETRY

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    Plantation-grown mahogany (Swietenia macrophylla) from Fiji has been preferred as a sus- tainable wood source for the craftingof electric guitars because its trade is not restricted by Convention on International Trade in Endangered Species of Wild Fauna andFlora (CITES), unlike S. macrophylla sourced from native forests. Ability to differentiate between the two wood types would deter sale of illegally harvested native-grown S. macrophylla to luthiers and other artisans. The chemical composition of wood is influenced bycambial age and geographical factors, and there are chemical differences between S. macrophylla grown in different regions. Thisstudy tested the ability of high-resolution mass spectrometry to chemotypically dif- ferentiate plantation-grown Fijian S. macrophylla from the same wood species obtained from native forests. Multiple heartwood specimens of both wood types were extracted and chromatographically profiled using gas and liquid chromatography tandem high-resolution quadrupole time-of-flight massspectrometry (GC/QToF, LC/QToF). Visual comparison of mass spectral ions, together with modern analytical data-mining techniques,were employed to screen the results. Principal component analysis scatter plots with 95% confidence ellipses showed unambiguousseparation of the two wood types by GC/LC/QToF. We conclude that screening of heartwood extractives using high-resolution massspectrometry offers an effective way of identifying and sepa- rating plantation-grown Fijian S. macrophylla from wood grown in native forests

    The organisational and human resource challenges facing primary care trusts : protocol of a multiple case study

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    BACKGROUND: The study is designed to assess the organisational and human resource challenges faced by Primary Care Trusts (PCTs). Its objectives are to: specify the organisational and human resources challenges faced by PCTs in fulfilling the roles envisaged in government and local policy; examine how PCTs are addressing these challenges, in particular, to describe the organisational forms they have adopted, and the OD/HR strategies and initiatives they have planned or in place; assess how effective these structures, strategies and initiatives have been in enabling the PCTs to meet the organisational and human resources challenges they face; identify the factors, both internal to the PCT and in the wider health community, which have contributed to the success or failure of different structures, strategies and initiatives. METHODS: The study will be undertaken in three stages. In Stage 1 the key literature on public sector and NHS organisational development and human resources management will be reviewed, and discussions will be held with key researchers and policy makers working in this area. Stage 2 will focus on detailed case studies in six PCTs designed to examine the organisational and human resources challenges they face. Data will be collected using semi-structured interviews, group discussion, site visits, observation of key meetings and examination of local documentation. The findings from the case study PCTs will be cross checked with a Reference Group of up to 20 other PCG/Ts, and key officers working in organisational development or primary care at local, regional and national level. In Stage 3 analysis of findings from the preparatory work, the case studies and the feedback from the Reference Group will be used to identify practical lessons for PCTs, key messages for policy makers, and contributions to further theoretical development

    Geographic Distribution of Childbirth among Adolescents in Cameroon from 2003 to 2005

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    Objective. To determine the frequency and the trend of adolescents (10–19 years) in childbirth within a period of 3 years in referral maternity units in Cameroon. Method. Descriptive and retrospective study for a 3-year period (2003–2005) in referral maternity units headed by a qualified Obstetrician-Gynecologist. We analyzed the trend and geographic distribution of 8222 adolescent deliveries over 3 years. Epi Info 3.5 software was used for data analysis. Chi square test for trend was used to assess the contribution of adolescent deliveries over years. The trend was considered significant if P < .05. Results. During the period of the study, there was a total of 8387 deliveries. We excluded 165 women because of lack of information about age. We therefore included a total of 8222 adolescent deliveries. Overall, the contribution of adolescents to deliveries ranged from 6.87% to 26.51%, depending on the region with a national mean of 14.23%. Adolescents aged 16 or less contributed to 2.82% of deliveries while those aged from 17 to 19 contributed to 11.41%. The contribution of adolescents to deliveries decreased significantly over 3 years (P < .0001). Conclusion. The study underscores the importance of Public Health programs in strengthening maternity services for adolescents in Cameroon while taking into consideration geographic differences

    Self-management of chronic low back pain: Four viewpoints from patients and healthcare providers

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    A move towards self-management is central to health strategy around chronic low back pain, but its concept and meaning for those involved are poorly understood. In the reported study, four distinct and shared viewpoints on self-management were identified among people with pain and healthcare providers using Q methodology. Each construes self-management in a distinctive manner and articulates a different vision of change. Identification of similarities and differences among the viewpoints holds potential for enhancing communication between patients and healthcare providers and for better understanding the complexities of self-management in practice

    Shared decision-making – Rhetoric and reality: Women’s experiences and perceptions of adjuvant treatment decision-making for breast cancer

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    This interview-based study uses phenomenology as a theoretical framework and thematic analysis to challenge existing explanatory frameworks of shared decision-making, in an exploration of women’s experiences and perceptions of shared decision-making for adjuvant treatment in breast cancer. Three themes emerged are as follows: (1) women’s desire to participate in shared decision-making, (2) the degree to which shared decision-making is perceived to be shared and (3) to what extent are women empowered within shared decision-making. Studying breast cancer patients’ subjective experiences of adjuvant treatment decision-making provides a broader perspective on patient participatory role preferences and doctor–patient power dynamics within shared decision-making for breast cancer
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