2,387 research outputs found

    The effects of multiple aerospace environmental stressors on human performance

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    An extended Fitt's law paradigm reaction time (RT) task was used to evaluate the effects of acceleration on human performance in the Dynamic Environment Simulator (DES) at Armstrong Laboratory, Wright-Patterson AFB, Ohio. This effort was combined with an evaluation of the standard CSU-13 P anti-gravity suit versus three configurations of a 'retrograde inflation anti-G suit'. Results indicated that RT and error rates increased 17 percent and 14 percent respectively from baseline to the end of the simulated aerial combat maneuver and that the most common error was pressing too few buttons

    Flare Forecasting Using the Evolution of McIntosh Sunspot Classifications

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    Most solar flares originate in sunspot groups, where magnetic field changes lead to energy build-up and release. However, few flare-forecasting methods use information of sunspot-group evolution, instead focusing on static point-in-time observations. Here, a new forecast method is presented based upon the 24-hr evolution in McIntosh classification of sunspot groups. Evolution-dependent \geqslantC1.0 and \geqslantM1.0 flaring rates are found from NOAA-numbered sunspot groups over December 1988 to June 1996 (Solar Cycle 22; SC22) before converting to probabilities assuming Poisson statistics. These flaring probabilities are used to generate operational forecasts for sunspot groups over July 1996 to December 2008 (SC23), with performance studied by verification metrics. Major findings are: i) considering Brier skill score (BSS) for \geqslantC1.0 flares, the evolution-dependent McIntosh-Poisson method (BSSevolution=0.09\text{BSS}_{\text{evolution}}=0.09) performs better than the static McIntosh-Poisson method (BSSstatic=0.09\text{BSS}_{\text{static}} = -0.09); ii) low BSS values arise partly from both methods over-forecasting SC23 flares from the SC22 rates, symptomatic of \geqslantC1.0 rates in SC23 being on average \approx80% of those in SC22 (with \geqslantM1.0 being \approx50%); iii) applying a bias-correction factor to reduce the SC22 rates used in forecasting SC23 flares yields modest improvement in skill relative to climatology for both methods (BSSstaticcorr=0.09\mathrm{BSS}^{\mathrm{corr}}_{\mathrm{static}} = 0.09 and BSSevolutioncorr=0.20\mathrm{BSS}^{\mathrm{corr}}_{\mathrm{evolution}} = 0.20) and improved forecast reliability diagrams.Comment: 21 pages, 9 figure

    Reinventing College Physics for Biologists: Explicating an epistemological curriculum

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    The University of Maryland Physics Education Research Group (UMd-PERG) carried out a five-year research project to rethink, observe, and reform introductory algebra-based (college) physics. This class is one of the Maryland Physics Department's large service courses, serving primarily life-science majors. After consultation with biologists, we re-focused the class on helping the students learn to think scientifically -- to build coherence, think in terms of mechanism, and to follow the implications of assumptions. We designed the course to tap into students' productive conceptual and epistemological resources, based on a theoretical framework from research on learning. The reformed class retains its traditional structure in terms of time and instructional personnel, but we modified existing best-practices curricular materials, including Peer Instruction, Interactive Lecture Demonstrations, and Tutorials. We provided class-controlled spaces for student collaboration, which allowed us to observe and record students learning directly. We also scanned all written homework and examinations, and we administered pre-post conceptual and epistemological surveys. The reformed class enhanced the strong gains on pre-post conceptual tests produced by the best-practices materials while obtaining unprecedented pre-post gains on epistemological surveys instead of the traditional losses.Comment: 35 pages including a 15 page appendix of supplementary material

    The contribution of teacher education to universities: a case study for international teacher educators

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    This paper reports on the initial stage of a research project which aims to develop deeper understanding of the contribution teacher education, as a sub-discipline within Education, makes to Higher Education in England. The study is located in the intersection between the domains of teacher education and higher education scholarship, which in England represents a contested and ambiguous professional space. Tensions between competing accountability measures, pulling away from university-based to exclusively school-based teacher education, are exacerbated by proposed policy changes arising from the government's recent market review. Findings drawn from analysis of qualitative data from a national survey are discussed in the context of Elizabeth Povinelli's critique of late liberalism and previous scholarship on the nature of teacher educators’ work. Evidence from the study demonstrates numerous benefits to higher education of hosting teacher education departments, including contributions to standard metrics, regional development and knowledge exchange within a strategic social justice agenda. However, teacher educators themselves may find articulating these benefits difficult, because of marginalisation from the dominant ways of achieving and accounting for excellence in the modern university. These findings offer a cautionary tale to international colleagues whose governments may be embarking on equivalent paths of teacher education reform

    Effective treatment of malignant hypercalcaemia with a single intravenous infusion of clodronate.

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    Thirty patients with hypercalcaemia due to malignancy that persisted following rehydration, were treated with a single dose of the bisphosphonate, clodronate. Clodronate (1.5 g) was administered intravenously in 500 ml normal saline over 4 h. Serum and urine biochemistry were measured before and after treatment and the results were compared with data from 15 patients given the recommended regimen 300 mg intravenous clodronate daily for 5 consecutive days. The single infusion induced a rapid and significant fall in serum calcium, apparent at day 3 (P < 0.0001) that persisted to the end of follow-up at day 10 (P < 0.001). Eighty per cent (24/30) of patients became normocalcaemic. The response was associated with a significant decrease in fasting urinary calcium excretion, and no change in renal function, as judged by serum creatinine. The same dose of clodronate, given as 5 daily infusions, induced a comparable decrease in serum calcium, but was less rapid in onset so that at day 3 the serum calcium was significantly lower with the single infusion (P = 0.02). The calcium lowering effect of both regimens depended on the tumour type. We conclude that the single infusion of 1500 mg clodronate is as effective in reducing serum calcium as the same dose given over 5 days. The single infusion has a more rapid onset of effect, is more convenient than multiple infusions, and has no adverse effect on renal function

    Epidemiology of osteoporotic fracture in Kazakhstan and development of a country specific FRAX model

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    Summary Retrospective and prospective population-based survey in a region of the Republic of Kazakhstan determined the incidence of fractures at the hip, proximal humerus and distal forearm. The hip fracture rates were used to create a FRAX® model to enhance fracture risk assessment in Kazakhstan. Objective This paper describes the epidemiology of osteoporotic fractures in the Republic of Kazakhstan that was used to develop a country specific FRAX® tool for fracture prediction. Methods We carried out a retrospective population-based survey in Taldykorgan in the Republic of Kazakhstan representing approximately 1% of the country’s population. Hip, forearm and humerus fractures were identified retrospectively in 2015 and 2016 from hospital registers and the trauma centre. Hip fractures were prospectively identified in 2017 from the same sources and additionally from primary care data. Age- and sex-specific incidence of hip fracture and national mortality rates were incorporated into a FRAX model for Kazakhstan. Fracture probabilities were compared with those from neighbouring countries having FRAX models. Results The difference in hip fracture incidence between the retrospective and prospective survey indicated that approximately 25% of hip fracture cases did not come to hospital attention. The incidence of hip fracture applied nationally suggested that the estimated number of hip fractures nationwide in persons over the age of 50 years for 2015 was 11,690 and is predicted to increase by 140% to 28,000 in 2050. Hip fracture incidence was a good predictor of forearm and humeral fractures in men but not in women. Conclusion The FRAX model should enhance accuracy of determining fracture probability among the Kazakh population and help guide decisions about treatment
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