137 research outputs found

    Statistical procedures for certification of software systems

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    Statistical approach to software reliability certification

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    Dynamics of two-component Bose-Einstein condensates in rotating traps

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    The dynamics of two-component Bose-Einstein condensates in rotating traps is investigated. In the Thomas-Fermi limit, equations of motion are derived showing multiple static solutions for a vortex free condensate. Dynamic stability analysis of these solutions and comparison with Truncated Wigner simulations enables us to identify the regimes for which vortex states will occur. In addition, our analysis predicts centre-of-mass oscillations that are induced by interspecies interactions and affect each component separately. For attractive interspecies interactions, these oscillations lead to a stable symmetry broken state.Comment: v4: more material added. 9 pages, 6 figures v5: figures fixed v6:some rewording v7:fixed figure

    Dynamics of two-component Bose-Einstein condensates in rotating traps

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    The dynamics of two-component Bose-Einstein condensates in rotating traps is investigated. In the Thomas-Fermi limit, equations of motion are derived showing multiple static solutions for a vortex free condensate. Dynamic stability analysis of these solutions and comparison with Truncated Wigner simulations enables us to identify the regimes for which vortex states will occur. In addition, our analysis predicts centre-of-mass oscillations that are induced by interspecies interactions and affect each component separately. For attractive interspecies interactions, these oscillations lead to a stable symmetry broken state.Comment: v4: more material added. 9 pages, 6 figures v5: figures fixed v6:some rewording v7:fixed figure

    Rotation of an atomic Bose-Einstein condensate with and without a quantized vortex

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    We theoretically examine the rotation of an atomic Bose-Einstein condensate in an elliptical trap, both in the absence and presence of a quantized vortex. Two methods of introducing the rotating potential are considered - adiabatically increasing the rotation frequency at fixed ellipticity, and adiabatically increasing the trap ellipticity at fixed rotation frequency. Extensive simulations of the Gross-Pitaevskii equation are employed to map out the points where the condensate becomes unstable and ultimately forms a vortex lattice. We highlight the key features of having a quantized vortex in the initial condensate. In particular, we find that the presence of the vortex causes the instabilities to shift to lower or higher rotation frequencies, depending on the direction of the vortex relative to the trap rotation.Comment: 15 pages, 8 figure

    The increasing importance of a continence nurse specialist to improve outcomes and save costs of urinary incontinence care

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    __Background:__ In an ageing population, it is inevitable to improve the management of care for community-dwellingelderly with incontinence. A previous study showed that implementation of the Optimum Continence ServiceSpecification (OCSS) for urinary incontinence in community-dwelling elderly with four or more chronic diseasesresults in a reduction of urinary incontinence, an improved quality of life, and lower healt

    Cost-effectiveness of adding rituximab to fludarabine and cyclophosphamide for treatment of chronic lymphocytic leukemia in Ukraine

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    The aim of this study was to assess the cost-effectiveness, from a health care perspective, of adding rituximab to fludarabine and cyclophosphamide scheme (FCR versus FC) for treatment-naïve and refractory/relapsed Ukrainian patients with chronic lymphocytic leukemia. A decision-analytic Markov cohort model with three health states and 1-month cycle time was developed and run within a life time horizon. Data from two multinational, prospective, open-label Phase 3 studies were used to assess patients’ survival. While utilities were generalized from UK data, local resource utilization and disease-associated treatment, hospitalization, and side effect costs were applied. The alternative scenario was performed to assess the impact of lower life expectancy of the general population in Ukraine on the incremental cost-effectiveness ratio (ICER) for treatment-naïve patients. One-way, two-way, and probabilistic sensitivity analyses were conducted to assess the robustness of the results. The ICER (in US dollars) of treating chronic lymphocytic leukemia patients with FCR versus FC is US8,704perqualityadjustedlifeyeargainedfortreatmentnaı¨vepatientsandUS8,704 per quality-adjusted life year gained for treatment-naïve patients and US11,056 for refractory/relapsed patients. When survival data were modified to the lower life expectancy of the general population in Ukraine, the ICER for treatment-naïve patients was higher than US13,000.ThisvalueishigherthanthreetimesthecurrentgrossdomesticproductpercapitainUkraine.SensitivityanalyseshaveshownahighimpactofrituximabcostsandamoderateimpactofdifferencesinutilitiesontheICER.Furthermore,probabilisticsensitivityanalyseshaveshownthatforrefractory/relapsedpatientstheprobabilityofFCRbeingcosteffectiveishigherthanfortreatmentnaı¨vepatientsandisclosetooneifthethresholdishigherthanUS13,000. This value is higher than three times the current gross domestic product per capita in Ukraine. Sensitivity analyses have shown a high impact of rituximab costs and a moderate impact of differences in utilities on the ICER. Furthermore, probabilistic sensitivity analyses have shown that for refractory/relapsed patients the probability of FCR being cost-effective is higher than for treatment-naïve patients and is close to one if the threshold is higher than US15,000. State coverage of rituximab treatment may be considered a cost-effective treatment for the Ukrainian population u
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