13,867 research outputs found
Neutronics Studies on the NIST Reactor Using the GA LEU fuel
The National Bureau of Standards Reactor (NBSR) located on the National Institute of Standards and Technology (NIST) Gaithersburg campus, is currently underway of fuel conversion from high enriched uranium (HEU) fuel to low enriched uranium (LEU) fuel. One particular challenging part of the conversion of the NBSR is the high average flux level (2.5×1014 n/cm2-s) required to maintain experimental testing capabilities of the reactor, without significant changes to the external structures of the reactor. Recently the General Atomics (GA) Training Research Isotopes General Atomics (TRIGA) fuel has shown some promising features as a LEU candidate for the high performance research reactors such as the NBSR. The GA fuel has a long history of success in conversion of research reactors since it was developed in 1980s. The UZrH compound in the GA fuel has seen success in long term TRIGA reactors, and is a proven safe LEU alternative. This study performs a neutronics evaluation of the TRIGA fuel under the schema of the NBSR’s heavy conversion requirements in order to examine whether the TRIGA fuel is a viable option for conversion of the NBSR. To determine the most optimal path of conversion, we performed a feasibility study with particular regard to the fuel dimensions, fuel rod configurations, cladding, as well as fuel structure selection. Based on the outcome of the feasibility study, an equilibrium core is then generated following the NBSR’s current fuel management schema. Key neutronics performance characteristics including flux distribution, power distribution, control rod (i.e., shim arms) worth, as well as kinetics parameters of the equilibrium core are calculated and evaluated. MCNP6, a Monte Carlo based computational modeling software was intensively used to aid in these calculations. The results of this study will provide important insight on the effectiveness of conversion, as well as determine the viability of the conversion from HEU to LEU using the GA fuel
Mortality in England and Wales attributable to current alcohol consumption.
STUDY OBJECTIVE: To estimate the number of deaths attributable to current alcohol consumption levels in England and Wales by age and sex. DESIGN: Epidemiological approach using published relative risks and population data. SETTING: England and Wales. MAIN OUTCOME MEASURES: Numbers of deaths by age and sex and years of life lost for alcohol related conditions. RESULTS: Because of the cardioprotective properties of alcohol, it is estimated that there are approximately 2% fewer deaths annually in England and Wales than would be expected in a non-drinking population. This proportion varies greatly by age and sex and only among men aged over 55 years and women aged over 65 years is there likely to be found a net favourable mortality balance. It is also estimated that there were approximately 75 000 premature years of life lost in England and Wales in 1996 attributable to alcohol consumption. The main causes of alcohol attributable mortality among the young include road traffic fatalities, suicide and alcoholic liver disease. CONCLUSIONS: At a population level, current alcohol consumption in England and Wales may marginally reduce mortality. However, the benefit is disproportionately found among the elderly. Estimating alcohol attributable mortality by age and sex may be a useful indicator for developing alcohol strategies. More research into the possible effect modifications of pattern of consumption, beverage type, age and gender will enable these estimates to be improved
Reasons why people change their alcohol consumption in later life: findings from the Whitehall II Cohort Study.
Harmful alcohol consumption among the ageing population is an important public health issue. Very few studies ask drinkers why they change their consumption in later life. The aim of this paper was to determine whether a group of people aged over 60 years increased or decreased their alcohol consumption over the past decade and to determine the reasons for their change. We also examined whether the responses varied by age, sex and socio-economic position (SEP)
Integrating research with NHS clinical practice: Unwelcome intrusion or constructive triangulation?
When embarking on research into the effectiveness of psychoanalytic psychotherapy in the NHS or the application of psychoanalytic principles, researchers come up against a number of hurdles: many clinicians still see empirical research as antithetical or disruptive to the practice of psychoanalytic psychotherapy; psychoanalytic psychotherapy has previously fared poorly in evidence-based policy guidelines and this can discourage ambition, and there are technical problems of research design, measurement and standardization. Nevertheless, in a political climate which stresses service evaluation, measurable outcomes and empirical evidence, psychoanalytic psychotherapy must participate to survive. There may be gains from conducting research beyond simply meeting the requirement to provide evidence of effectiveness. Research may be viewed by some clinicians as an unwelcome intruder but it may have the potential to offer triangulation, the perspective of the 'third', and so strengthen the foundations of clinical practice and the development of psychoanalytic thought
Economy on cruise control in 2010 and 2011
According to participants in the Chicago Fed’s annual Automotive Outlook Symposium, solid economic growth is forecasted for the nation this year and in 2011. Inflation is expected to remain contained, but the unemployment rate is anticipated to remain high. Light vehicle sales are forecasted to improve moderately in 2010 and 2011.Automobiles - Prices ; Inflation (Finance)
Economic Outlook Symposium: summary of 2009 results and forecasts for 2010
According to participants in the Chicago Fed’s annual Economic Outlook Symposium, solid economic growth is forecasted for the nation in 2010, following a very sharp contraction during 2008 and the first half of 2009; inflation is expected to increase in 2010; and the unemployment rate is predicted to peak early in 2010 and edge lower throughout the year.
Does access to cardiac investigation and treatment contribute to social and ethnic differences in coronary heart disease? Whitehall II prospective cohort study
Objective: To determine whether access to cardiac procedures and drugs contributes to social and ethnic differences in coronary heart disease in a population setting. Design: Prospective study with follow up over 15 years. Civil service employment grade was used as a measure of individual socioeconomic position. Need for cardiac care was determined by the presence of angina, myocardial infarction, and coronary risk factors. Setting: 20 civil service departments originally located in London. Participants: 10 308 civil servants (3414 women; 560 South Asian) aged 35-55 years at baseline in 1985-8. Main outcome measures: Use of exercise electrocardiography, coronary angiography, and coronary revascularisation procedures and secondary prevention drugs. Results: Inverse social gradients existed in incident coronary morbidity and mortality. South Asian participants also had higher rates than white participants. After adjustment for clinical need, social position showed no association with the use of cardiac procedures or secondary prevention drugs. For example, men in the low versus high employment grade had an age adjusted odds ratio for angiography of 1.87 (95% confidence interval 1.32 to 2.64), which decreased to 1.27 (0.83 to 1.94) on adjustment for clinical need. South Asians tended to be more likely to have cardiac procedures and to be taking more secondary prevention drugs than white participants, even after adjustment for clinical need. Conclusion: This population based study, which shows the widely observed social and ethnic patterning of coronary heart disease, found no evidence that low social position or South Asian ethnicity was associated with lower use of cardiac procedures or drugs, independently of clinical need. Differences in medical care are unlikely to contribute to social or ethnic differences in coronary heart disease in this cohort
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