1,491 research outputs found
ADL1 - an atomic data library for use in computing the behaviour of plasma devices including fusion reactors.
A data library with self-descriptive format is presented. This library provides on a fixed temperature grid reaction rate coefficients effective degree of ionisation and data for line radiation power emission for 59 ion or neutral species. Data are presented for neutral and ionised atoms of the hydrogen isotopes and for 49 'impurity' ion species ranging from helium-3 and -4 to uranium. Data origins are also discussed
Understanding children’s experiences of self-wetting in humanitarian contexts: An evaluation of the Story Book methodology
Little is known about how children in humanitarian contexts experience self-wetting. Children can wet themselves due to having the medical condition of urinary incontinence (the involuntary leakage of urine), or due to them not wanting to or not being able to use the toilet facilities available (social or functional incontinence). Self-wetting is a global public health challenge: the physical health of children can suffer; they can miss out on educational and social opportunities; they may face increased protection risks; and the emotional effect on daily life can be significantly negative. The Story Book methodology was developed to facilitate conversations with children aged five to eleven in humanitarian contexts (specifically refugee settlements in Adjumani District, Uganda; and refugee camps in Cox’s Bazar, Bangladesh) about self-wetting to understand how humanitarian professionals can best meet the needs of children that wet themselves. This paper has evaluated how far the Story Book methodology meets the specific requirements of conducting research a) in a humanitarian context; b) with young children; and c) on a personal and highly sensitive topic. Data has been used from Story Book sessions held with children in Adjumani District and Cox’s Bazar, and from semi-structured interviews held with adults known to have participated in the planning and/or facilitation of the sessions. The evaluation found that although the Story Book methodology provided deep insights into how children in humanitarian contexts experience self-wetting, it was not always implemented as designed; it is not practical to implement in humanitarian settings; and it was not acceptable to all participants and facilitators as a research tool. Changes have been recommended to improve the methodology as a research tool to better understand how children experience personal health issues, but even with such changes the methodology will remain better suited to non-humanitarian contexts
A Dynamic Model of Interactions of Ca^(2+), Calmodulin, and Catalytic Subunits of Ca^(2+)/Calmodulin-Dependent Protein Kinase II
During the acquisition of memories, influx of Ca^(2+) into the postsynaptic spine through the pores of activated N-methyl-D-aspartate-type glutamate receptors triggers processes that change the strength of excitatory synapses. The pattern of Ca^(2+) influx during the first few seconds of activity is interpreted within the Ca^(2+)-dependent signaling network such that synaptic strength is eventually either potentiated or depressed. Many of the critical signaling enzymes that control synaptic plasticity, including Ca^(2+)/calmodulin-dependent protein kinase II (CaMKII), are regulated by calmodulin, a small protein that can bind up to 4 Ca^(2+) ions. As a first step toward clarifying how the Ca^(2+)-signaling network decides between potentiation or depression, we have created a kinetic model of the interactions of Ca^(2+), calmodulin, and CaMKII that represents our best understanding of the dynamics of these interactions under conditions that resemble those in a postsynaptic spine. We constrained parameters of the model from data in the literature, or from our own measurements, and then predicted time courses of activation and autophosphorylation of CaMKII under a variety of conditions. Simulations showed that species of calmodulin with fewer than four bound Ca^(2+) play a significant role in activation of CaMKII in the physiological regime, supporting the notion that processing ofCa^(2+) signals in a spine involves competition among target enzymes for binding to unsaturated species of CaM in an environment in which the concentration of Ca^(2+) is fluctuating rapidly. Indeed, we showed that dependence of activation on the frequency of Ca^(2+) transients arises from the kinetics of interaction of fluctuating Ca^(2+) with calmodulin/CaMKII complexes. We used parameter sensitivity analysis to identify which parameters will be most beneficial to measure more carefully to improve the accuracy of predictions. This model provides a quantitative base from which to build more complex dynamic models of postsynaptic signal transduction during learning
Estimating bank default with generalised extreme value regression models
The paper proposes a novel model for the prediction of bank failures, on the basis of both macroeconomic and bank-specific microeconomic factors. As bank failures are rare, in the paper we apply a regression method for binary data based on extreme value theory, which turns out to be more effective than classical logistic regression models, as it better leverages the information in the tail of the default distribution. The application of this model to the occurrence of bank defaults in a highly bank dependent economy (Italy) shows that, while microeconomic factors as well as regulatory capital are significant to explain proper failures, macroeconomic factors are relevant only when failures are defined not only in terms of actual defaults but also in terms of mergers and acquisitions. In terms of predictive accuracy, the model based on extreme value theory outperforms classical logistic regression models
Use pattern of maternal health services and determinants of skilled care during delivery in Southern Tanzania: implications for achievement of MDG-5 targets
Almost two decades since the initiation of the Safe motherhood Initiative, Maternal Mortality is still soaring high in most developing countries. In 2000 WHO estimated a life time risk of a maternal death of 1 in 16 in Sub- Saharan Africa while it was only 1 in 2800 in developed countries. This huge discrepancy in the rate of maternal deaths is due to differences in access and use of maternal health care services. It is known that having a skilled attendant at every delivery can lead to marked reductions in maternal mortality. For this reason, the proportion of births attended by skilled health personnel is one of the indicators used to monitor progress towards the achievement of the MDG-5 of improving maternal health. Cross sectional study which employed quantitative research methods. We interviewed 974 women who gave birth within one year prior to the survey. Although almost all (99.8%) attended ANC at least once during their last pregnancy, only 46.7% reported to deliver in a health facility and only 44.5% were assisted during delivery by a skilled attendant. Distance to the health facility (OR = 4.09 (2.72-6.16)), discussion with the male partner on place of delivery (OR = 2.37(1.75-3.22)), advise to deliver in a health facility during ANC (OR = 1.43 (1.25-2.63)) and knowledge of pregnancy risk factors (OR 2.95 (1.65-5.25)) showed significant association with use of skilled care at delivery even after controlling for confounding factors. Use of skilled care during delivery in this district is below the target set by ICPD + of attaining 80% of deliveries attended by skilled personnel by 2005. We recommend the following in order to increase the pace towards achieving the MDG targets: to improve coverage of health facilities, raising awareness for both men and women on danger signs during pregnancy/delivery and strengthening counseling on facility delivery and individual birth preparedness
Multiday expected shortfall under generalized t distributions : evidence from global stock market
We apply seven alternative t-distributions to estimate the market risk measures Value at Risk (VaR) and its
extension Expected Shortfall (ES). Of these seven, the twin t-distribution (TT) of Baker and Jackson (2014) and
generalized asymmetric distribution (GAT) of Baker (2016) are applied for the first time to estimate market risk.
We analytically estimate VaR and ES over one-day horizon and extend this to multi-day horizon using Monte
Carlo simulation. We find that taken together TT and GAT distributions provide the best back-testing results
across individual confidence levels and horizons for majority of scenarios. Moreover, we find that with the
lengthening of time horizon, TT and GAT models performs well, such that at the ten-day horizon, GAT provides
the best back-testing results for all of the five indices and the TT model provides the second best results,
irrespective period of study and confidence level
The association between low level exposures to ambient air pollution and term low birth weight: a retrospective cohort study
BACKGROUND: Studies in areas with relatively high levels of air pollution have found some positive associations between exposures to ambient levels of air pollution and several birth outcomes including low birth weight (LBW). The purpose of this study was to examine the association between LBW among term infants and ambient air pollution, by trimester of exposure, in a region of lower level exposures. METHODS: The relationship between LBW and ambient levels of particulate matter up to 10 um in diameter (PM(10)), sulfur dioxide (SO(2)) and ground-level ozone (O(3)) was evaluated using the Nova Scotia Atlee Perinatal Database and ambient air monitoring data from the Environment Canada National Air Pollution Surveillance Network and the Nova Scotia Department of Environment. The cohort consisted of live singleton births (≥37 weeks of gestation) between January1,1988 and December31,2000. Maternal exposures to air pollution were assigned to women living within 25 km of a monitoring station at the time of birth. Air pollution was evaluated as a continuous and categorical variable (using quartile exposures) for each trimester and relative risks were estimated from logistic regression, adjusted for confounding variables. RESULTS: There were 74,284 women with a term, singleton birth during the study period and with exposure data. In the analyses unadjusted for year of birth, first trimester exposures in the highest quartile for SO(2 )and PM(10)suggested an increased risk of delivering a LBW infant (relative risk = 1.36, 95% confidence interval = 1.04 to 1.78 for SO(2 )exposure and relative risk = 1.33, 95% confidence interval = 1.02 to 1.74 for PM(10)). After adjustment for birth year, the relative risks were attenuated somewhat and not statistically significant. A dose-response relationship for SO(2 )was noted with increasing levels of exposure. No statistically significant effects were noted for ozone. CONCLUSION: Our results suggest that exposure during the first trimester to relatively low levels of some air pollutants may be associated with a reduction in birth weight in term-born infants. These findings have implications for the development of effective risk management strategies to minimize the public health impacts for pregnant women
Calibration of GENEActiv accelerometer wrist cut-points for the assessment of physical activity intensity of pre-school aged children
This study sought to validate cut-points for use of wrist worn GENEActiv accelerometer data, to analyse preschool children’s (4 to 5 year olds) physical activity (PA) levels via calibration with oxygen consumption values (VO2). This was a laboratory based calibration study. Twenty-one preschool children, aged 4.7 ± 0.5 years old, completed six activities (ranging from lying supine to running) whilst wearing the GENEActiv accelerometers at two locations (left and right wrist), these being the participants’ non-dominant and dominant wrist, and a Cortex face mask for gas analysis. VO2 data was used for the assessment of criterion validity. Location specific activity intensity cut points were established via Receiver Operator Characteristic curve (ROC) analysis. The GENEActiv accelerometers, irrespective of their location, accurately discriminated between all PA intensities (sedentary, light, and moderate and above), with the dominant wrist monitor providing a slightly more precise discrimination at light PA and the non-dominant at the sedentary behaviour and moderate and above intensity levels (Area Under the Curve (AUC) for non-dominant = 0.749-0.993, compared to AUC dominant = 0.760-0.988). Conclusion: This study establishes wrist-worn physical activity cut points for the GENEActiv accelerometer in pre-schoolers.N/
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