1,157 research outputs found

    Kinetic Analysis of Discrete Path Sampling Stationary Point Databases

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    Analysing stationary point databases to extract phenomenological rate constants can become time-consuming for systems with large potential energy barriers. In the present contribution we analyse several different approaches to this problem. First, we show how the original rate constant prescription within the discrete path sampling approach can be rewritten in terms of committor probabilities. Two alternative formulations are then derived in which the steady-state assumption for intervening minima is removed, providing both a more accurate kinetic analysis, and a measure of whether a two-state description is appropriate. The first approach involves running additional short kinetic Monte Carlo (KMC) trajectories, which are used to calculate waiting times. Here we introduce `leapfrog' moves to second-neighbour minima, which prevent the KMC trajectory oscillating between structures separated by low barriers. In the second approach we successively remove minima from the intervening set, renormalising the branching probabilities and waiting times to preserve the mean first-passage times of interest. Regrouping the local minima appropriately is also shown to speed up the kinetic analysis dramatically at low temperatures. Applications are described where rates are extracted for databases containing tens of thousands of stationary points, with effective barriers that are several hundred times kT.Comment: 28 pages, 1 figure, 4 table

    Financial capability, money attitudes and socioeconomic status: risks for experiencing adverse financial events

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    The risk of experiencing adverse financial events (e.g. bankruptcy) depends on the world economy and on individual differences in financial and psychological variables. Analysing data from 109,472 British survey respondents, this study reports the risks associated with financial capabilities, money attitudes, and socio-economic status for suffering negative financial outcomes. The results show that (1) socio-economic status is associated with financial capabilities but not with money attitudes; (2) money attitudes and financial capabilities are largely independent; (3) money attitudes and financial capabilities each contribute independently to the risk of experiencing adverse financial outcomes, even after adjusting for socio-economic status; and (4) financial capabilities are greater risk factors of adverse financial outcomes than money attitudes; the latter, however, are likely to be promising targets for interventions

    Generating natural language specifications from UML class diagrams

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    Early phases of software development are known to be problematic, difficult to manage and errors occurring during these phases are expensive to correct. Many systems have been developed to aid the transition from informal Natural Language requirements to semistructured or formal specifications. Furthermore, consistency checking is seen by many software engineers as the solution to reduce the number of errors occurring during the software development life cycle and allow early verification and validation of software systems. However, this is confined to the models developed during analysis and design and fails to include the early Natural Language requirements. This excludes proper user involvement and creates a gap between the original requirements and the updated and modified models and implementations of the system. To improve this process, we propose a system that generates Natural Language specifications from UML class diagrams. We first investigate the variation of the input language used in naming the components of a class diagram based on the study of a large number of examples from the literature and then develop rules for removing ambiguities in the subset of Natural Language used within UML. We use WordNet,a linguistic ontology, to disambiguate the lexical structures of the UML string names and generate semantically sound sentences. Our system is developed in Java and is tested on an independent though academic case study

    The effects of social service contact on teenagers in England

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    Objective: This study investigated outcomes of social service contact during teenage years. Method: Secondary analysis was conducted of the Longitudinal Survey of Young People in England (N = 15,770), using data on reported contact with social services resulting from teenagers’ behavior. Outcomes considered were educational achievement and aspiration, mental health, and locus of control. Inverse-probability-weighted regression adjustment was used to estimate the effect of social service contact. Results: There was no significant difference between those who received social service contact and those who did not for mental health outcome or aspiration to apply to university. Those with contact had lower odds of achieving good exam results or of being confident in university acceptance if sought. Results for locus of control were mixed. Conclusions: Attention is needed to the role of social services in supporting the education of young people in difficulty. Further research is needed on the outcomes of social services contact

    Born radicals? Prevent, positivism, and ‘race-thinking’

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    In the contemporary Western climate, counter-terrorism discourse dealing with so-called Islamic extremism appears to be obsessed with trying to understand the motives behind what prompts somebody to turn to terrorism. This paper will argue that attempts to locate extremist motives in such a way can be seen to reinforce earlier iterations of positivist criminology and race-thinking. Through a critical examination of the works of criminologist Cesare Lombroso, this paper will tease out the interconnections between his ‘criminal types’ thesis, and the British government’s current Prevent policy that seeks to identify ‘extremist types.’ By developing a rich critique of these positivist approaches, the paper will go on to question how we might think beyond the essentialism, reductivism, and racism/Islamophobia inherent within such frameworks. In this way, the paper raises a series of conceptual implications for criminology and terrorism studies, while at the same time, develops a contribution to critical race and ethnicity studies

    Psychometric precision in phenotype definition is a useful step in molecular genetic investigation of psychiatric disorders

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    Affective disorders are highly heritable, but few genetic risk variants have been consistently replicated in molecular genetic association studies. The common method of defining psychiatric phenotypes in molecular genetic research is either a summation of symptom scores or binary threshold score representing the risk of diagnosis. Psychometric latent variable methods can improve the precision of psychiatric phenotypes, especially when the data structure is not straightforward. Using data from the British 1946 birth cohort, we compared summary scores with psychometric modeling based on the General Health Questionnaire (GHQ-28) scale for affective symptoms in an association analysis of 27 candidate genes (249 single-nucleotide polymorphisms (SNPs)). The psychometric method utilized a bi-factor model that partitioned the phenotype variances into five orthogonal latent variable factors, in accordance with the multidimensional data structure of the GHQ-28 involving somatic, social, anxiety and depression domains. Results showed that, compared with the summation approach, the affective symptoms defined by the bi-factor psychometric model had a higher number of associated SNPs of larger effect sizes. These results suggest that psychometrically defined mental health phenotypes can reflect the dimensions of complex phenotypes better than summation scores, and therefore offer a useful approach in genetic association investigations

    Personalization in the health care system: do personal health budgets impact on outcomes and cost?

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    Objectives In England’s National Health Service, personal health budgets are part of a growing trend to give patients more choice and control over how health care services are managed and delivered. The personal health budget programme was launched by the Department of Health in 2009, and a three-year independent evaluation was commissioned with the aim of identifying whether the initiative ensured better health- and care-related outcomes and at what cost when compared to conventional service delivery. Methods The evaluation used a pragmatic controlled trial design to compare the outcomes and costs of patients selected to receive a personal health budget with those continuing with conventional support arrangements (control group). Just over 1000 individuals were recruited into the personal health budget group and 1000 into the control group in order to ensure sufficient statistical power, and followed for 12 months. Results The use of personal health budgets was associated with significant improvement in patients’ care-related quality of life and psychological wellbeing at 12 months. Personal health budgets did not appear to have an impact on health status, mortality rates, health-related quality of life or costs over the same period. With net benefits measured in terms of care-related quality of life on the adult social care outcome toolkit measure, personal health budgets were cost-effective: that is, budget holders experienced greater benefits than people receiving conventional services, and the budgets were worth the cost. Conclusion The evaluation provides support for the planned wider roll-out of personal health budgets in the English NHS after 2014 in so far as the localities in the pilot sample are representative of the whole country

    Exploring older women's confidence during route planning

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    In-car route guidance is automatic, requiring a minimum of time and thinking. This paper explores the use of personalised information when providing instructions for navigating a journey. We focus on older women with a lifetime of experience. Ten female participants were interviewed to elicit their comfort zone with respect to navigating in a car from their own home. Two routes were then devised for each participant, which extended beyond this comfort zone, and presented to them in two different formats. Participants then navigated the route of their least preferred format. Questionnaires and interviews were used to explore the effects of the formats on their confidence, cognitive effort and use of cognitive mapping facilities. The questionnaire data showed that the more detailed instructions supported cognitive mapping processes and the interviews suggested that this support was valued prio

    Why do women invest in pre-pregnancy health and care? A qualitative investigation with women attending maternity services

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    Background Despite the importance attributed to good pre-pregnancy care and its potential to improve pregnancy and child health outcomes, relatively little is known about why women invest in pre-pregnancy health and care. We sought to gain insight into why women invested in pre-pregnancy health and care. Methods We carried out 20 qualitative in-depth interviews with pregnant or recently pregnant women who were drawn from a survey of antenatal clinic attendees in London, UK. Interviewees were purposively sampled to include high and low investors in pre-pregnancy health and care, with variation in age, partnership status, ethnicity and pre-existing medical conditions. Data analysis was conducted using the Framework method. Results We identified three groups in relation to pre-pregnancy health and care: 1) The “prepared” group, who had high levels of pregnancy planning and mostly positive attitudes to micronutrient supplementation outside of pregnancy, carried out pre-pregnancy activities such as taking folic acid and making changes to diet and lifestyle. 2) The “poor knowledge” group, who also had high levels of pregnancy planning, did not carry out pre-pregnancy activities and described themselves as having poor knowledge. Elsewhere in their interviews they expressed a strong dislike of micronutrient supplementation. 3) The “absent pre-pregnancy period” group, had the lowest levels of pregnancy planning and also expressed anti-supplement views. Even discussing the pre-pregnancy period with this group was difficult as responses to questions quickly shifted to focus on pregnancy itself. Knowledge of folic acid was poor in all groups. Conclusion Different pre-pregnancy care approaches are likely to be needed for each of the groups. Among the “prepared” group, who were proactive and receptive to health messages, greater availability of information and better response from health professionals could improve the range of pre-pregnancy activities carried out. Among the “poor knowledge” group, better response from health professionals might yield greater uptake of pre-pregnancy information. A different, general health strategy might be more appropriate for the “absent pre-pregnancy period” group. The fact that general attitudes to micronutrient supplementation were closely related to whether or not women invested in pre-pregnancy health and care was an unanticipated finding and warrants further investigation.This report is independent research commissioned and funded by the Department of Health Policy Research Programme Pre-Pregnancy Health and Care in England: Exploring Implementation and Public Health Impact, 006/0068

    Cancer risks in populations living near landfill sites in Great Britain

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    Previous studies have raised concerns about possible excess risks of bladder, brain and hepatobiliary cancers and leukaemias near landfill sites. Several cancers have been implicated, but no consistent pattern has emerged. We present a large nationwide analysis of selected cancers near landfill sites in Great Britain. The base population comprised people living within 2 km of 9565 (from a total of 19 196) landfill sites that were operational at some time from 1982 to 1997, with populations living more than 2 km from a landfill as reference. Risks of cancers at the above sites were computed with adjustment for age, sex, year of diagnosis, region and deprivation. National post-coded registers provided a total of 341 856 640 person–years for the adult cancer analyses and 113 631 443 person–years for childhood leukaemia. There were 89 786 cases of bladder cancer, 36 802 cases of brain cancer, 21 773 cases of hepatobiliary cancer, 37 812 cases of adult leukaemia and 3973 cases of childhood leukaemia. In spite of the very large scale of this national study, we found no excess risks of cancers of the bladder and brain, hepatobiliary cancer or leukaemia, in populations living within 2 km of landfill sites. The results were similar if the analysis were restricted to landfill sites licensed to carry special (hazardous) waste. Our results do not support suggestions of excess risks of cancer associated with landfill sites reported in other studies
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