1,422 research outputs found

    The Hamiltonian Extended Krylov Subspace Method

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    General practitioners' views and preferences about quality improvement feedback in preventive care: a cross-sectional study in Switzerland and France.

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    Feedback is widely used as a strategy to improve the quality of care in primary care settings. As part of a study conducted to explore the quality of preventive care, we investigated general practitioners' (GPs) views on the usefulness of feedback and their preferences regarding how feedback is provided. This cross-sectional study was conducted in 2015 among randomly selected community-based GPs in two regions of Switzerland and France. GPs were asked to complete an anonymous questionnaire about how often they provided 12 measures of preventive care: blood pressure, weight and height measurements, screening for dyslipidemia, at-risk drinking (and advice to reduce for at-risk drinkers), smoking (and advice to stop for smokers), colon and prostate cancer, and influenza immunization for patients >65 years and at-risk patients. They were also asked to estimate the usefulness of a feedback regarding their preventive care practice, reason(s) for which a feedback could be useful, and finally, to state which type of feedback they would like to receive. Chi-square tests were used to compare frequencies. Multivariate logistic regression was used to identify factors associated with GPs considering feedback as useful. Five hundred eighteen of 1100 GPs (47.1%) returned the questionnaire. They were predominantly men (62.5%) and most (40.1%) were aged between 55 and 64 years old. Overall, 44.3% stated that a feedback would be useful. Younger GPs and those carrying out more measures of preventive care were more likely to consider feedback useful. The two main reasons for being interested in feedback were to receive knowledge about the study results and to modify or improve practice. The two preferred feedback interventions were a brief report and a report with specific information regarding prevention best practice, whereas less than 1% would like to discuss the results face-to-face with the study investigators. These findings suggest that GPs have preferences regarding the types of feedback they would like to receive. Because the implementation of guidelines is highly related to the acceptance of feedback, we strongly encourage decision makers to take GPs' preferences into account when developing strategies to implement guidelines, in order to improve the quality of primary care

    Rates, Delays, and Completeness of General Practitioners' Responses to a Postal Versus Web-Based Survey: A Randomized Trial.

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    Web-based surveys have become a new and popular method for collecting data, but only a few studies have directly compared postal and Web-based surveys among physicians, and none to our knowledge among general practitioners (GPs). Our aim is to compare two modes of survey delivery (postal and Web-based) in terms of participation rates, response times, and completeness of questionnaires in a study assessing GPs' preventive practices. This randomized study was conducted in Western Switzerland (Geneva and Vaud) and in France (Alsace and Pays de la Loire) in 2015. A random selection of community-based GPs (1000 GPs in Switzerland and 2400 GPs in France) were randomly allocated to receive a questionnaire about preventive care activities either by post (n=700 in Switzerland, n=400 in France) or by email (n=300 in Switzerland, n=2000 in France). Reminder messages were sent once in the postal group and twice in the Web-based group. Any GPs practicing only complementary and alternative medicine were excluded from the study. Among the 3400 contacted GPs, 764 (22.47%, 95% CI 21.07%-23.87%) returned the questionnaire. Compared to the postal group, the participation rate in the Web-based group was more than four times lower (246/2300, 10.70% vs 518/1100, 47.09%, P<.001), but median response time was much shorter (1 day vs 1-3 weeks, P<.001) and the number of GPs having fully completed the questionnaire was almost twice as high (157/246, 63.8% vs 179/518, 34.6%, P<.001). Web-based surveys offer many advantages such as reduced response time, higher completeness of data, and large cost savings, but our findings suggest that postal surveys can be still considered for GP research. The use of mixed-mode approaches is probably a good strategy to increase GPs' participation in surveys while reducing costs

    Transmission resonances and supercritical states in a one dimensional cusp potential

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    We solve the two-component Dirac equation in the presence of a spatially one dimensional symmetric cusp potential. We compute the scattering and bound states solutions and we derive the conditions for transmission resonances as well as for supercriticality.Comment: 10 pages. Revtex 4. To appear in Phys Rev.

    The Woods-Saxon Potential in the Dirac Equation

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    The two-component approach to the one-dimensional Dirac equation is applied to the Woods-Saxon potential. The scattering and bound state solutions are derived and the conditions for a transmission resonance (when the transmission coefficient is unity) and supercriticality (when the particle bound state is at E=-m) are then derived. The square potential limit is discussed. The recent result that a finite-range symmetric potential barrier will have a transmission resonance of zero-momentum when the corresponding well supports a half-bound state at E=-m is demonstrated.Comment: 8 pages, 4 figures. Submitted to JPhys

    Understanding Variation in Sets of N-of-1 Trials.

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    A recent paper in this journal by Chen and Chen has used computer simulations to examine a number of approaches to analysing sets of n-of-1 trials. We have examined such designs using a more theoretical approach based on considering the purpose of analysis and the structure as regards randomisation that the design uses. We show that different purposes require different analyses and that these in turn may produce quite different results. Our approach to incorporating the randomisation employed when the purpose is to test a null hypothesis of strict equality of the treatment makes use of Nelder's theory of general balance. However, where the purpose is to make inferences about the effects for individual patients, we show that a mixed model is needed. There are strong parallels to the difference between fixed and random effects meta-analyses and these are discussed

    How do general practitioners put preventive care recommendations into practice? A cross-sectional study in Switzerland and France.

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    We previously identified that general practitioners (GPs) in French-speaking regions of Europe had a variable uptake of common preventive recommendations. In this study, we describe GPs' reports of how they put different preventive recommendations into practice. Cross-sectional study conducted in 2015 in Switzerland and France. 3400 randomly selected GPs were asked to complete a postal (n=1100) or online (n=2300) questionnaire. GPs who exclusively practiced complementary and alternative medicine were not eligible for the study. 764 GPs (response rate: postal 47%, online 11%) returned the questionnaire (428 in Switzerland and 336 in France). We investigated how the GPs performed five preventive practices (screening for dyslipidaemia, colorectal and prostate cancer, identification of hazardous alcohol consumption and brief intervention), examining which age group they selected, the screening frequency, the test they used, whether they favoured shared decision for prostate cancer screening and their definition of hazardous alcohol use. A large variability was observed in the way in which GPs provide these practices. 41% reported screening yearly for cholesterol, starting and stopping at variable ages. 82% did not use any test to identify hazardous drinking. The most common responses for defining hazardous drinking were, for men, ≥21 drinks/week (24%) and ≥4 drinks/occasion for binge drinking (20%), and for women, ≥14 drinks/week (28%) and ≥3 drinks/occasion (21%). Screening for colorectal cancer, mainly with colonoscopy in Switzerland (86%) and stool-based tests in France (93%), was provided every 10 years in Switzerland (65%) and 2 years in France (91%) to patients between 50 years (87%) and 75 years (67%). Prostate cancer screening, usually with shared decision (82%), was provided yearly (62%) to patients between 50 years (74%) and 75-80 years (32%-34%). The large diversity in the way these practices are provided needs to be addressed, as it could be related to some misunderstandingof the current guidelines, to barriers for guideline uptake or, more likely, to the absence of agreement between the various recommendations

    A European multicentre prospective randomized study to assess the use of assisted hatching with a diode laser and the benefit of an immunosuppressive/antibiotic treatment in different patient populations

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    BACKGROUND: Assisted hatching (AH) techniques, designed for facilitating the embryo escape out of the zona pellucida (ZP) have been used in IVF centres since 1992. The initial indications for AH were patient's age, ZP thickness, high basal FSH and repeated IVF failures. Several retrospective and prospective studies assessing AH in these indications have given disparate results. Our aims were to evaluate the benefits of AH and immunosuppressive/antibiotic treatment (IA) in patients with either a poor prognosis of success, previous implantation failures or transfers of cryopreserved embryos. METHODS: Four IVF centres allocated 426 patients, randomized for AH and IA, into four groups of AH indications between 1997 and 1999. AH was performed with a diode laser. ZP thickness, opening size and embryo score were recorded. Outcome measures were implantation and delivery rates. RESULTS: Patients coming for a first or third transfer of cryopreserved embryos and poor prognosis patients admitted for a first trial did not benefit from AH. Even patients with repeated implantation failures of fresh embryos did not gain significantly from AH. CONCLUSIONS: Among AH indications, absence of implantation after several transfers of good quality embryos remains the strongest patient selection criterion. Prescription of an immunosuppressive/antibiotic treatment is essentia

    Size Dependence of Metal-Insulator Transition in Stoichiometric Fe3O4 Nanocrystals

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    Magnetite (Fe3O4) is one of the most actively studied materials with a famous metal-insulator transition (MIT), so-called the Verwey transition at around 123 K. Despite the recent progress in synthesis and characterization of Fe3O4 nanocrystals (NCs), it is still an open question how the Verwey transition changes on a nanometer scale. We herein report the systematic studies on size dependence of the Verwey transition of stoichiometric Fe3O4 NCs. We have successfully synthesized stoichiometric and uniform-sized Fe3O4 NCs with sizes ranging from 5 to 100 nm. These stoichiometric Fe3O4 NCs show the Verwey transition when they are characterized by conductance, magnetization, cryo-XRD, and heat capacity measurements. The Verwey transition is weakly size-dependent and becomes suppressed in NCs smaller than 20 nm before disappearing completely for less than 6 nm, which is a clear, yet highly interesting indication of a size effect of this well-known phenomena. Our current work will shed new light on this ages-old problem of Verwey transition.Comment: 18 pages, 4 figures, Nano Letters (accepted

    Initial prognostic factors in small-cell lung cancer patients predicting quality of life during chemotherapy. Swiss Group for Clinical Cancer Research (SAKK).

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    The question of whether initial prognostic factors in small-cell lung cancer patients have a predictive value for patients' quality of life (QL) during chemotherapy is addressed in the context of a randomised clinical trial comparing early and late alternating chemotherapy (SAKK protocol 15/84). The relative impact of initial tumour stage and performance status, previous weight loss, sex and age on patient-rated QL was analysed over six chemotherapy cycles in 124-130 patients (according to available QL data) with more than 400 questionnaires. Fatigue/malaise, personal functioning, emotional and general well-being were prospectively selected as QL indicators. Predefined summary measures (average QL score over chemotherapy cycles, 'minimum', 'maximum' and 'final' improvement) were analysed separately by scale in various patient groups. General linear models adjusted for treatment arm and response were used to confirm the univariate findings. Within the overall sample, the average QL scores over six cycles were predicted by initial prognostic factors. Patients with poor prognostic factors reported worse QL. Within a limited sample (with baseline QL), patients with poor prognostic factors reported worse QL at baseline and greater improvement under treatment. Graphical comparison of QL patterns over cycles showed permanent discrimination by levels of prognostic factors. The impact of initial prognostic factors was consistently confirmed in the three analyses. Levels of performance status and weight loss best discriminated QL. Initial tumour stage, performance status and previous weight loss can predict QL in small-cell lung cancer during chemotherapy, even after controlling for response to treatment. Our results may contribute to clinical decision-making with regard to the intensity of chemotherapy and QL outcome, especially in patients with extensive disease
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