487 research outputs found

    Dr. Doodle: A diagrammatic theorem prover

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    This paper presents the Dr.Doodle system, an interactive theorem prover that uses diagrammatic representations. The assumption underlying this project is that, for some domains (principally geometry) , diagrammatic reasoning is easier to understand than conventional algebraic approaches -- at least for a significant number of people. The Dr.Doodle system was developed for the domain of metric-space analysis (a geometric domain, but traditionally taught using a dry algebraic formalism). Pilot experiments were conducted to evaluate its potential as the basis of an educational tool, with encouraging results

    Encountering #Feminism on Twitter:Reflections on a research collaboration between social scientists and computer scientists

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    The growth of social media presents an unparalleled opportunity for the study of social change. However, the speed and scale of this growth presents challenges for social scientists, particularly those whose methodologies tend to rely on the qualitative analysis of data that are gathered firsthand. Alongside the growth of social media, companies have emerged which have developed tools for interrogating ‘big data’, although often unconnected from social scientists. It is self-evident that collaboration between social scientists and social media analysis companies offers the potential for developing methods for analysing social change on large scales, bringing together their respective expertise in technological innovations and knowledge of social science. What is less well known is how such a partnership might work in practice. This article presents an example of such a collaboration, highlighting the opportunities and challenges that arose in the context of an exploration of feminism on Twitter. As will be shown, machine-learning technologies allow the analysis of data on a scale that would be impossible for human analysts, yet such approaches also heighten challenges regarding the study of social change and communication. </jats:p

    Prevalence and correlates of antipsychotic polypharmacy in children and adolescents receiving antipsychotic treatment*

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    Antipsychotic polypharmacy (APP), which is common in adults with psychotic disorders, is of unproven efficacy and raises safety concerns. Although youth are increasingly prescribed antipsychotics, little is known about APP in this population. We performed a systematic PubMed search (last update 26 January 2013) of studies reporting the prevalence of APP in antipsychotic-treated youth. Summary statistics and statistical tests were calculated at the study level and not weighted by sample size. Fifteen studies (n=58041, range 68-23183) reported on APP in youth [mean age=13.4 +/- 1.7 yr, 67.1 +/- 10.2% male, 77.9 +/- 27.4% treated with second-generation antipsychotics (SGAs)]. Data collected in these studies covered 1993-2008. The most common diagnoses were attention-deficit hyperactivity disorder (ADHD; 39.9 +/- 23.5%) and conduct disorder/oppositional defiant disorder (CD/ODD; 33.6 +/- 24.8). In studies including predominantly children (mean age=yr, N=5), the most common diagnosis were ADHD (50.6 +/- 25.4%) and CD/ODD (39.5 +/- 27.5%); while in studies with predominantly adolescents (mean age=13yr, N=7) the most common diagnoses were schizophrenia-spectrum disorders (28.6 +/- 23.8%), anxiety disorders (26.9 +/- 14.9%) and bipolar-spectrum disorders (26.6 +/- 7.0%), followed closely by CD/ODD (25.8 +/- 17.7). The prevalence of APP among antipsychotic-treated youth was 9.6 +/- 7.2% (5.9 +/- 4.5% in child studies, 12.0 +/- 7.9% in adolescent studies, p=0.15). Higher prevalence of APP was correlated with a bipolar disorder or schizophrenia diagnosis (p=0.019) and APP involving SGA+SGA combinations (p=0.0027). No correlation was found with APP definition [1d (N=10) vs. \u3e30-90d (N=5), p=0.88]. Despite lacking safety and efficacy data, APP in youth is not uncommon, even in samples predominantly consisting of non-psychotic patients. The duration, clinical motivations and effectiveness of this practice require further study

    Micro-CT-based analysis of fibre-reinforced composites:Applications

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    The paper presents an overview of cases in which the analysis of the internal structure and mechanical properties of fibre reinforced composites is performed based on the micro-computed X-ray tomography (micro-CT) reconstruction of the composite reinforcement geometry. In all the cases, the analysis relies on structure tensor-based algorithms for quantification of the micro-CT image, implemented in VoxTex software

    A systematic review of the safety of lisdexamfetamine dimesylate

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    BACKGROUND: Here we review the safety and tolerability profile of lisdexamfetamine dimesylate (LDX), the first long-acting prodrug stimulant for the treatment of attention-deficit/hyperactivity disorder (ADHD). METHODS: A PubMed search was conducted for English-language articles published up to 16 September 2013 using the following search terms: (lisdexamfetamine OR lisdexamphetamine OR SPD489 OR Vyvanse OR Venvanse OR NRP104 NOT review [publication type]). RESULTS: In short-term, parallel-group, placebo-controlled, phase III trials, treatment-emergent adverse events (TEAEs) in children, adolescents, and adults receiving LDX were typical for those reported for stimulants in general. Decreased appetite was reported by 25-39 % of patients and insomnia by 11-19 %. The most frequently reported TEAEs in long-term studies were similar to those reported in the short-term trials. Most TEAEs were mild or moderate in severity. Literature relating to four specific safety concerns associated with stimulant medications was evaluated in detail in patients receiving LDX. Gains in weight, height, and body mass index were smaller in children and adolescents receiving LDX than in placebo controls or untreated norms. Insomnia was a frequently reported TEAE in patients with ADHD of all ages receiving LDX, although the available data indicated no overall worsening of sleep quality in adults. Post-marketing survey data suggest that the rate of non-medical use of LDX was lower than that for short-acting stimulants and lower than or equivalent to long-acting stimulant formulations. Small mean increases were seen in blood pressure and pulse rate in patients receiving LDX. CONCLUSIONS: The safety and tolerability profile of LDX in individuals with ADHD is similar to that of other stimulants

    Primary care medication safety surveillance with integrated primary and secondary care electronic health records: a cross-sectional study

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    Introduction: The extent of preventable medication-related hospital admissions and medication-related issues in primary care is significant enough to justify developing decision support systems for medication safety surveillance. The prerequisite for such systems is defining a relevant set of medication safety-related indicators and understanding the influence of both patient and general practice characteristics on medication prescribing and monitoring. Objective: The aim of the study was to investigate the feasibility of linked primary and secondary care electronic health record data for surveillance of medication safety, examining not only prescribing but also monitoring, and associations with patient- and general practice-level characteristics. Methods: A cross-sectional study was conducted using linked records of patients served by one hospital and over 50 general practices in Salford, UK. Statistical analysis consisted of mixed-effects logistic models, relating prescribing safety indicators to potential determinants. Results: The overall prevalence (proportion of patients with at least one medication safety hazard) was 5.45 % for prescribing indicators and 7.65 % for monitoring indicators. Older patients and those on multiple medications were at higher risk of prescribing hazards, but at lower risk of missed monitoring. The odds of missed monitoring among all patients were 25 % less for males, 50 % less for patients in practices that provide general practitioner training, and threefold higher in practices serving the most deprived compared with the least deprived areas. Practices with more prescribing hazards did not tend to show more monitoring issues. Conclusions:Systematic collection, collation, and analysis of linked primary and secondary care records produce plausible and useful information about medication safety for a health system. Medication safety surveillance systems should pay close attention to patient age and polypharmacy with respect to both prescribing and monitoring failures; treat prescribing and monitoring as different statistical processes, rather than a combined measure of prescribing safety; and audit the socio-economic equity of missed monitoring

    Editorial: Observational studies in ADHD: the effects of switching to modified-release methylphenidate preparations on clinical outcomes and adherence

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    Patients with ADHD may have better adherence to treatment with modified-release methylphenidate (MPH-MR) formulations, which are taken once daily, compared with immediate-release (IR) formulations, which need to be taken several times a day. Data on long-term outcomes such as adherence may be lacking from randomised controlled trials as these are usually only short-term. Observational studies, if performed and reported appropriately, can provide valuable long-term data on such outcomes, as well as additional information on effectiveness and efficiency, from a real-life setting. By reviewing previous observational studies that have investigated switching treatment from MPH-IR to MPH-MR, results from a new, naturalistic observational study, the OBSEER study, are put into context. We conclude that, based on observational trial data, switching from MPH-IR to MPH-MR is a valid clinical approach, with the potential for improved clinical outcome and treatment adherence

    Damage measurements on the NWTC direct-drive, Variable-Speed Test Bed

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    The NWTC (National Wind Technology Center) Variable-Speed Test Bed turbine is a three-bladed, 10-meter, downwind machine that can be run in either fixed-speed or variable-speed mode. In the variable-speed mode, the generator torque is regulated, using a discrete-stepped load bank to maximize the turbine`s power coefficient. At rated power, a second control loop that uses blade pitch to maintain rotor speed essentially as before, i.e., using the load bank to maintain either generator power or (optionally) generator torque. In this paper, the authors will use this turbine to study the effect of variable-speed operation on blade damage. Using time-series data obtained from blade flap and edge strain gauges, the load spectrum for the turbine is developed using rainflow counting techniques. Miner`s rule is then used to determine the damage rates for variable-speed and fixed-speed operation. The results illustrate that the controller algorithm used with this turbine introduces relatively large load cycles into the blade that significantly reduce its service lifetime, while power production is only marginally increased
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