149 research outputs found

    Efficient algorithms for dynamic probabilistic safety assessment. An application to convex damage domain.

    Full text link
    The design of nuclear power plant has to follow a number of regulations aimed at limiting the risks inherent in this type of installation. The goal is to prevent and to limit the consequences of any possible incident that might threaten the public or the environment. To verify that the safety requirements are met a safety assessment process is followed. Safety analysis is as key component of a safety assessment, which incorporates both probabilistic and deterministic approaches. The deterministic approach attempts to ensure that the various situations, and in particular accidents, that are considered to be plausible, have been taken into account, and that the monitoring systems and engineered safety and safeguard systems will be capable of ensuring the safety goals. On the other hand, probabilistic safety analysis tries to demonstrate that the safety requirements are met for potential accidents both within and beyond the design basis, thus identifying vulnerabilities not necessarily accessible through deterministic safety analysis alone. Probabilistic safety assessment (PSA) methodology is widely used in the nuclear industry and is especially effective in comprehensive assessment of the measures needed to prevent accidents with small probability but severe consequences. Still, the trend towards a risk informed regulation (RIR) demanded a more extended use of risk assessment techniques with a significant need to further extend PSA’s scope and quality. Here is where the theory of stimulated dynamics (TSD) intervenes, as it is the mathematical foundation of the integrated safety assessment (ISA) methodology developed by the CSN(Consejo de Seguridad Nuclear) branch of Modelling and Simulation (MOSI). Such methodology attempts to extend classical PSA including accident dynamic analysis, an assessment of the damage associated to the transients and a computation of the damage frequency. The application of this ISA methodology requires a computational framework called SCAIS (Simulation Code System for Integrated Safety Assessment). SCAIS provides accident dynamic analysis support through simulation of nuclear accident sequences and operating procedures. Furthermore, it includes probabilistic quantification of fault trees and sequences; and integration and statistic treatment of risk metrics. SCAIS comprehensively implies an intensive use of code coupling techniques to join typical thermal hydraulic analysis, severe accident and probability calculation codes. The integration of accident simulation in the risk assessment process and thus requiring the use of complex nuclear plant models is what makes it so powerful, yet at the cost of an enormous increase in complexity. As the complexity of the process is primarily focused on such accident simulation codes, the question of whether it is possible to reduce the number of required simulation arises, which will be the focus of the present work. This document presents the work done on the investigation of more efficient techniques applied to the process of risk assessment inside the mentioned ISA methodology. Therefore such techniques will have the primary goal of decreasing the number of simulation needed for an adequate estimation of the damage probability. As the methodology and tools are relatively recent, there is not much work done inside this line of investigation, making it a quite difficult but necessary task, and because of time limitations the scope of the work had to be reduced. Therefore, some assumptions were made to work in simplified scenarios best suited for an initial approximation to the problem. The following section tries to explain in detail the process followed to design and test the developed techniques. Then, the next section introduces the general concepts and formulae of the TSD theory which are at the core of the risk assessment process. Afterwards a description of the simulation framework requirements and design is given. Followed by an introduction to the developed techniques, giving full detail of its mathematical background and its procedures. Later, the test case used is described and result from the application of the techniques is shown. Finally the conclusions are presented and future lines of work are exposed

    Una lectura psicoanalĂ­tica del Rorschach

    Get PDF
    En funciĂłn de la importancia del diagnĂłstico para determinar la direcciĂłn de la cura, se trabaja con dos herramientas fundamentales para dicha tarea: el psicoanĂĄlisis y el test de Rorschach. La conceptualizaciĂłn que Jacques Lacan aporta, en base a Sigmund Freud acerca de la estructuraciĂłn y funcionamiento del psiquismo, favorece precisiones en el diagnĂłstico al permitir considerar que el mismo se desarrolla en base al discurso que se articula en funciĂłn de los procesos inconscientes, siendo Ă©stos, los que dan cuenta de la particularidad de cada sujeto. Considerando el desarrollo teĂłrico y clĂ­nico alcanzado por la tĂ©cnica creada por Rorschach, con las contribuciones de Exner y de la Escuela Argentina, y teniendo en cuenta la validĂ©z de los datos que aporta, se trabajan conceptos bĂĄsicos del test y su articulaciĂłn con el psicoanĂĄlisis. A travĂ©s de un caso, se examinan las posibilidades que los datos del Rorschach ofrecen para su lectura, con el auxilio de la teorĂ­a psicoanalĂ­tica desde el grafo del deseo. El anĂĄlisis que se realiza se centra en la exploraciĂłn del sumario estructural, analizando los recursos como la relaciĂłn del sujeto con el deseo, desde donde debe resolver las tensiones originadas por la bĂșsqueda de satisfacciones pulsionales, y la presencia del superyĂł.Fil: Cicutto, Aldo Nelso

    Local Anodizing of a Newly Prepared Aluminum Micrometric Disk

    Get PDF
    A search through the literature reveals that the vast majority of studies about aluminum anodizing were conducted at the macroscale (i.e., from cm2 up to m2), while those focused on local anodizing (i.e., on surfaces of less than 1 mm2) are rare. The last ones either used insulating masks or were conducted in an electrolyte droplet. The present study describes on the one hand a new way to prepare aluminum microelectrodes of conventional disk-shaped geometry, and on the other hand the local anodizing of their respective aluminum micrometric top-disks. The influence of the anodizing voltage on anodic film characteristics (i.e., thickness, growth rate and expansion factor) was studied during local anodizing. Compared with the values reported for macroscopic anodizing, the pore diameter appears to be significantly low and the film growth rate can reach atypically high values, both specificities probably resulting from a very limited increase in the temperature on the aluminum surface during anodizing

    Asthma education for school staff.

    Get PDF
    BACKGROUND: Teachers and school staff should be competent in managing asthma in schools. Demonstrated low levels of asthma knowledge mean that staff may not know how best to protect a child with asthma in their care, or may fail to take appropriate action in the event of a serious attack. Education about asthma could help to improve this knowledge and lead to better asthma outcomes for children. OBJECTIVES: To assess the effectiveness and safety of asthma education programmes for school staff, and to identify content and attributes underpinning them. SEARCH METHODS: We conducted the most recent searches on 29 November 2016. SELECTION CRITERIA: We included randomised controlled trials comparing an intervention to educate school staff about asthma versus a control group. We included studies reported as full text, those published as abstract only and unpublished data. DATA COLLECTION AND ANALYSIS: At least two review authors screened the searches, extracted outcome data and intervention characteristics from included studies and assessed risk of bias. Primary outcomes for the quantitative synthesis were emergency department (ED) or hospital visits, mortality and asthma control; we graded the main results and presented evidence in a 'Summary of findings' table. We planned a qualitative synthesis of intervention characteristics, but study authors were unable to provide the necessary information.We analysed dichotomous data as odds ratios, and continuous data as mean differences or standardised mean differences, all with a random-effects model. We assessed clinical, methodological and statistical heterogeneity when performing meta-analyses, and we narratively described skewed data. MAIN RESULTS: Five cluster-RCTs of 111 schools met the review eligibility criteria. Investigators measured outcomes in participating staff and often in children or parents, most often at between 1 and 12 months.All interventions were educational programmes but duration, content and delivery varied; some involved elements of training for pupils or primary care providers. We noted risk of selection, performance, detection and attrition biases, although to a differing extent across studies and outcomes.Quanitative and qualitative analyses were limited. Only one study reported visits to the ED or hospital and provided data that were too skewed for analysis. No studies reported any deaths or adverse events. Studies did not report asthma control consistently, but results showed no difference between groups on the paediatric asthma quality of life questionnaire (mean difference (MD) 0.14, 95% confidence interval (CI) -0.03 to 0.31; 1005 participants; we downgraded the quality of evidence to low for risk of bias and indirectness). Data for symptom days, night-time awakenings, restricted activities of daily living and school absences were skewed or could not be analysed; some mean scores were better in the trained group, but most differences between groups were small and did not persist to 24 months.Schools that received asthma education were more adherent to asthma policies, and staff were better prepared; more schools that had received staff asthma training had written asthma policies compared with control schools, more intervention schools showed improvement in measures taken to prevent or manage exercise-induced asthma attacks and more staff at intervention schools reported that they felt able to administer salbutamol via a spacer. However, the quality of the evidence was low; results show imbalances at baseline, and confidence in the evidence was limited by risk of bias and imprecision. Staff knowledge was higher in groups that had received asthma education, although results were inconsistent and difficult to interpret owing to differences between scales (low quality).Available information about the interventions was insufficient for review authors to conduct a meaningful qualitative synthesis of the content that led to a successful intervention, or of the resources required to replicate results accurately. AUTHORS' CONCLUSIONS: Asthma education for school staff increases asthma knowledge and preparedness, but studies vary and all available evidence is of low quality. Studies have not yet captured whether this improvement in knowledge has led to appreciable benefits over the short term or the longer term for the safety and health of children with asthma in school. Randomised evidence does not contribute to our knowledge of content or attributes of interventions that lead to the best outcomes, or of resources required for successful implementation.Complete reporting of the content and resources of educational interventions is essential for assessment of their effectiveness and feasibility for implementation. This applies to both randomised and non-randomised studies, although the latter may be better placed to observe important clinical outcomes such as exacerbations and mortality in the longer term

    Examining intra-rater and inter-rater response agreement: A medical chart abstraction study of a community-based asthma care program

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>To assess the intra- and inter-rater agreement of chart abstractors from multiple sites involved in the evaluation of an Asthma Care Program (ACP).</p> <p>Methods</p> <p>For intra-rater agreement, 110 charts randomly selected from 1,433 patients enrolled in the ACP across eight Ontario communities were re-abstracted by 10 abstractors. For inter-rater agreement, data abstractors reviewed a set of eight fictitious charts. Data abstraction involved information pertaining to six categories: physical assessment, asthma control, spirometry, asthma education, referral visits, and medication side effects. Percentage agreement and the kappa statistic (Îș) were used to measure agreement. Sensitivity and specificity estimates were calculated comparing results from all raters against the gold standard.</p> <p>Results</p> <p>Intra-rater re-abstraction yielded an overall kappa of 0.81. Kappa values for the chart abstraction categories were: physical assessment (Îș 0.84), asthma control (Îș 0.83), spirometry (Îș 0.84), asthma education (Îș 0.72), referral visits (Îș 0.59) and medication side effects (Îș 0.51). Inter-rater abstraction of the fictitious charts produced an overall kappa of 0.75, sensitivity of 0.91 and specificity of 0.89. Abstractors demonstrated agreement for physical assessment (Îș 0.88, sensitivity and specificity 0.95), asthma control (Îș 0.68, sensitivity 0.89, specificity 0.85), referral visits (Îș 0.77, sensitivity 0.88, specificity 0.95), and asthma education (Îș 0.49, sensitivity 0.87, specificity 0.77).</p> <p>Conclusion</p> <p>Though collected by multiple abstractors, the results show high sensitivity and specificity and substantial to excellent inter- and intra-rater agreement, assuring confidence in the use of chart abstraction for evaluating the ACP.</p

    How much do health care providers value a community-based asthma care program? – a survey to collect their opinions on the utilities of and barriers to its uptake

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>A comprehensive asthma care program (ACP) based on Canadian Asthma Consensus Guidelines was implemented in 8 primary care sites in Ontario, Canada. A survey was distributed to health care providers' (HCPs) to collect their opinions on the utilities of and barriers to the uptake of the ACP.</p> <p>Methods</p> <p>A 39-item self-administered survey was mailed to 184 HCPs and support staff involved in delivering the ACP at the end of implementation. The items were presented in mixed formats with most items requiring responses on a five-point Likert scale. Distributions of responses were analyzed and compared across types of HCPs and sites.</p> <p>Results</p> <p>Of the 184 surveys distributed, 108 (59%) were returned, and of that, 83 were completed by HCPs who had clinical contact with the patients. Overall, 95% of the HCPs considered the ACP useful for improving asthma care management. Most HCPs favored using the asthma care map (72%), believed it decreased uncertainties and variations in patient management (91%), and considered it a convenient and reliable source of information (86%). The most commonly reported barrier was time required to complete the asthma care map. Over half of the HCPs reported challenges to using spirometry, while almost 40% identified barriers to using the asthma action plan.</p> <p>Conclusion</p> <p>Contrary to the notion that physicians believe that guidelines foster cookbook medicine, our study showed that HCPs believed that the ACP offered an effective and reliable approach for enhancing asthma care and management in primary care.</p

    Realidad educativa en Mendoza: violencia y consumo en adolescentes insertos en escuelas y universidades.

    Get PDF
    La adolescencia implica sujetos en proceso de desarrollo. En dicho proceso, los adultos  son referentes necesarios: cumplen  funciones de protección, amparo,  guía, y orden. Los adultos de hoy tienen dificultades para ejercer la autoridad. Los sujetos que disponen de referentes adecuados tienen mayores posibilidades de resolver las situaciones que se les presentan sin caer en actos de violencia y consumo desubjetivante

    Self-care support for children and adolescents with long-term conditions : the REfOCUS evidence synthesis

    Get PDF
    Background: Self-care support (e.g. education, training, peer/professional support) is intended to enhance the self-care capacities of children and young people, while simultaneously reducing the financial burden facing health-care systems. Objectives: To determine which models of self-care support for long-term conditions (LTCs) are associated with significant reductions in health utilisation and costs without compromising outcomes for children and young people. Design: Systematic review with meta-analysis. Population: Children and young people aged 0–18 years with a long-term physical or mental health condition (e.g. asthma, depression). Intervention: Self-care support in health, social care, educational or community settings. Comparator: Usual care. Outcomes: Generic/health-related quality of life (QoL)/subjective health symptoms and health service utilisation/costs. Design: Randomised/non-randomised trials, controlled before-and-after studies, and interrupted time series designs. Data sources: MEDLINE, EMBASE, PsycINFO, Cumulative Index to Nursing and Allied Health Literature, ISI Web of Science, NHS Economic Evaluation Database, The Cochrane Library, Health Technology Assessment database, Paediatric Economic Database Evaluation, IDEAS, reference scanning, targeted author searches and forward citation searching. All databases were searched from inception to March 2015. Methods: We conducted meta-analyses, simultaneously plotting QoL and health utilisation effects. We conducted subgroup analyses for evidence quality, age, LTC and intervention (setting, target, delivery format, intensity). Results: Ninety-seven studies reporting 114 interventions were included. Thirty-seven studies reported adequate allocation concealment. Fourteen were UK studies. The vast majority of included studies recruited children and young people with asthma (n = 66, 68%). Four per cent of studies evaluated ‘pure’ self-care support (delivered through health technology without additional contact), 23% evaluated facilitated self-care support (≀ 2 hours’/four sessions’ contact), 65% were intensively facilitated (≄ 2 hours’/four sessions’ contact) and 8% were case management (≄ 2 hours’ support with multidisciplinary input). Self-care support was associated with statistically significant, minimal benefits for QoL [effect size (ES) –0.17, 95% confidence interval (CI) –0.23 to –0.11], but lacked clear benefit for hospital admissions (ES –0.05, 95% CI –0.12 to 0.03). This finding endured across intervention intensities and LTCs. Statistically significant, minimal reductions in emergency use were observed (ES –0.11, 95% CI –0.17 to –0.04). The total cost analysis was limited by the small number of data. Subgroup analyses revealed statistically significant, minimal reductions in emergency use for children aged ≀ 13 years (ES –0.10, 95% CI –0.17 to –0.04), children and young people with asthma (ES –0.12, 95% CI –0.18 to –0.06) and children and young people receiving ≄ 2 hours per four sessions of support (ES –0.10, 95% CI –0.17 to –0.03). Preliminary evidence suggested that interventions that include the child or young person, and deliver some content individually, may optimise QoL effects. Face-to-face delivery may help to maximise emergency department effects. Caution is required in interpreting these findings. Limitations: Identification of optimal models of self-care support is challenged by the size and nature of evidence available. The emphasis on meta-analysis meant that a minority of studies with incomplete but potentially relevant data were excluded. Conclusions: Self-care support is associated with positive but minimal effects on children and young people’s QoL, and minimal, but potentially important, reductions in emergency use. On current evidence, we cannot reliably conclude that self-care support significantly reduces health-care costs. Future work: Research is needed to explore the short- and longer-term effects of self-care support across a wider range of LTCs. Study registration: This study is registered as PROSPERO CRD42014015452. Funding: The National Institute for Health Research Health Services and Delivery Research programme
    • 

    corecore