741 research outputs found

    Complexity Results for Modal Dependence Logic

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    Modal dependence logic was introduced recently by V\"a\"an\"anen. It enhances the basic modal language by an operator =(). For propositional variables p_1,...,p_n, =(p_1,...,p_(n-1);p_n) intuitively states that the value of p_n is determined by those of p_1,...,p_(n-1). Sevenster (J. Logic and Computation, 2009) showed that satisfiability for modal dependence logic is complete for nondeterministic exponential time. In this paper we consider fragments of modal dependence logic obtained by restricting the set of allowed propositional connectives. We show that satisfibility for poor man's dependence logic, the language consisting of formulas built from literals and dependence atoms using conjunction, necessity and possibility (i.e., disallowing disjunction), remains NEXPTIME-complete. If we only allow monotone formulas (without negation, but with disjunction), the complexity drops to PSPACE-completeness. We also extend V\"a\"an\"anen's language by allowing classical disjunction besides dependence disjunction and show that the satisfiability problem remains NEXPTIME-complete. If we then disallow both negation and dependence disjunction, satistiability is complete for the second level of the polynomial hierarchy. In this way we completely classify the computational complexity of the satisfiability problem for all restrictions of propositional and dependence operators considered by V\"a\"an\"anen and Sevenster.Comment: 22 pages, full version of CSL 2010 pape

    Dynamics of Dengue epidemics using optimal control

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    We present an application of optimal control theory to Dengue epidemics. This epidemiologic disease is an important theme in tropical countries due to the growing number of infected individuals. The dynamic model is described by a set of nonlinear ordinary differential equations, that depend on the dynamic of the Dengue mosquito, the number of infected individuals, and the people's motivation to combat the mosquito. The cost functional depends not only on the costs of medical treatment of the infected people but also on the costs related to educational and sanitary campaigns. Two approaches to solve the problem are considered: one using optimal control theory, another one by discretizing first the problem and then solving it with nonlinear programming. The results obtained with OC-ODE and IPOPT solvers are given and discussed. We observe that with current computational tools it is easy to obtain, in an efficient way, better solutions to Dengue problems, leading to a decrease of infected mosquitoes and individuals in less time and with lower costs.Comment: Submitted to Mathematical and Computer Modelling 25/Oct/2009; accepted for publication, after revision, 22/June/201

    National geological screening : the Hampshire Basin and adjoining areas

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    This report is the published product of one of a series of studies covering England, Wales and Northern Ireland commissioned by Radioactive Waste Management (RWM) Ltd. The report provides geological information about the Hampshire Basin and adjoining areas region to underpin the process of national geological screening set out in the UK’s government White Paper Implementing geological disposal: a framework for the long-term management of higher activity radioactive waste (DECC, 2014). The report describes geological features relevant to the safety requirements of a geological disposal facility (GDF) for radioactive waste emplaced onshore and up to 20 km offshore at depths between 200 and 1000 m from surface. It is written for a technical audience but is intended to inform RWM in its discussions with communities interested in finding out about the potential for their area to host a GDF

    National geological screening : London and the Thames Valley

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    This report is the published product of one of a series of studies covering England, Wales and Northern Ireland commissioned by Radioactive Waste Management (RWM) Ltd. The report provides geological information about the London and the Thames Valley region to underpin the process of national geological screening set out in the UK Government’s White Paper Implementing geological disposal: a framework for the long-term management of higher activity radioactive waste (DECC, 2014). The report describes geological features relevant to the safety requirements of a geological disposal facility (GDF) for radioactive waste emplaced onshore and up to 20 km offshore at depths between 200 and 1000 m from surface. It is written for a technical audience but is intended to inform RWM in its discussions with communities interested in finding out about the potential for their area to host a GDF

    The bulk correlation length and the range of thermodynamic Casimir forces at Bose-Einstein condensation

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    The relation between the bulk correlation length and the decay length of thermodynamic Casimir forces is investigated microscopically in two three-dimensional systems undergoing Bose-Einstein condensation: the perfect Bose gas and the imperfect mean-field Bose gas. For each of these systems, both lengths diverge upon approaching the corresponding condensation point from the one-phase side, and are proportional to each other. We determine the proportionality factors and discuss their dependence on the boundary conditions. The values of the corresponding critical exponents for the decay length and the correlation length are the same, equal to 1/2 for the perfect gas, and 1 for the imperfect gas

    Patterns and clinical correlates of lifetime alcohol consumption in women and men with bipolar disorder: findings from the UK Bipolar Disorder Research Network

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    Objectives Despite previous literature on comorbid alcohol use disorders (AUDs) in bipolar disorder (BD), little is known about patterns of alcohol use more widely in this population. We have examined lifetime heaviest average weekly alcohol consumption levels in a large well‐characterised UK sample including lifetime clinical correlates of increasing levels of alcohol use. Methods Participants were 1203 women and 673 men with bipolar I disorder interviewed by semi‐structured interview who had consumed alcohol regularly at any point in their life. Results Over half of both women (52.3%) and men (73.6%) had regularly consumed over double the current UK recommended guideline for alcohol consumption. In women and men increasing levels of lifetime alcohol consumption were significantly associated with the presence of suicide attempts (women: OR 1.82, P < .001; men: OR 1.48, P = .005) and rapid cycling (women: OR 1.89, P < .001; men: OR 1.88, P < .001). In women only, increasing levels of alcohol consumption were significantly associated with more episodes of depression (OR 1.35, P < .001) and mania (OR 1.30, P < .004) per illness year, less impairment in functioning during the worst episode of mania (OR 1.02, P < .001), fewer psychiatric admissions (OR 0.51, P < .001), comorbid panic disorder (OR 2.16, P < .001) and eating disorder (OR 2.37, P < .001). Conclusions Our results highlight the clinical importance of obtaining detailed information on levels of alcohol consumption among patients with BD. Increased levels of alcohol use, not necessarily reaching criteria for AUD, may be helpful in predicting BD illness course, in particular eating disorders comorbidity in women

    National geological screening : Northern Ireland

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    This report is the published product of one of a series of studies covering England, Wales and Northern Ireland commissioned by Radioactive Waste Management (RWM) Ltd. The report provides geological information about Northern Ireland to underpin its process of national geological screening set out in the UK’s government White Paper Implementing geological disposal: a framework for the long-term management of higher activity radioactive waste (DECC, 2014). The report describes geological features relevant to the safety requirements of a geological disposal facility (GDF) for radioactive waste emplaced onshore and up to 20 km offshore at depths between 200 and 1000 m from surface. It is written for a technical audience but is intended to inform RWM in its discussions with communities interested in finding out about the potential for their area to host a GDF

    Acute Treatment Effects on GFR in Randomized Clinical Trials of Kidney Disease Progression

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    Background: Acute changes in GFR can occur after initiation of interventions targeting progression of CKD. These acute changes complicate the interpretation of long-term treatment effects. Methods: To assess the magnitude and consistency of acute effects in randomized clinical trials and explore factors that might affect them, we performed a meta-analysis of 53 randomized clinical trials for CKD progression, enrolling 56,413 participants with at least one estimated GFR measurement by 6 months after randomization. We defined acute treatment effects as the mean difference in GFR slope from baseline to 3 months between randomized groups. We performed univariable and multivariable metaregression to assess the effect of intervention type, disease state, baseline GFR, and albuminuria on the magnitude of acute effects. Results: The mean acute effect across all studies was 20.21 ml/min per 1.73 m2 (95% confidence interval, 20.63 to 0.22) over 3 months, with substantial heterogeneity across interventions (95% coverage interval across studies, 22.50 to 12.08 ml/min per 1.73 m2). We observed negative average acute effects in renin angiotensin system blockade, BP lowering, and sodium-glucose cotransporter 2 inhibitor trials, and positive acute effects in trials of immunosuppressive agents. Larger negative acute effects were observed in trials with a higher mean baseline GFR. Conclusion: The magnitude and consistency of acute GFR effects vary across different interventions, and are larger at higher baseline GFR. Understanding the nature and magnitude of acute effects can help inform the optimal design of randomized clinical trials evaluating disease progression in CKD
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