3,486 research outputs found

    Measurement of the derivative 'ZW' for an oscillating aerofoil

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    This report presents the results of experimental measurements of the damping derivative coefficient zw for constant chord rigid wings of various aspect ratios having sweepback angles of zero and 450. The results for the rectangular wings Flow substantial agreement with the unsteady aerofoil theory developed by TI.P. Jones $2) The dependence of Zvi upon frequency parameter is as given by theory and is much less than for two dimensional flow, but the numerical results are approximately 10 per cent below the theoretical. This is attributed to the large trailing edge angle 22° of the N.A.C.A. 0020 section used for the model aerofoils. The effect of sweepback is to decrease the numerical value of z , but this effect is much less pronounced, for low than for high aspect ratios. For aspect ratios 5 and 3 the numerical value is greater than would be given by a factor of proportionality equal to the cosine of the angle of sweepback. The measurements were corrected for tunnel interference by a method based on the theoretical work of 7.P.Jones.(1

    Predicting airborne coronavirus inactivation by far-UVC in populated rooms using a high-fidelity coupled radiation-CFD model

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    There are increased risks of contracting COVID-19 in hospitals and long-term care facilities, particularly for vulnerable groups. In these environments aerosolised coronavirus released through breathing increases the chance of spreading the disease. To reduce aerosol transmissions, the use of low dose far-UVC lighting to disinfect in-room air has been proposed. Unlike typical UVC, which has been used to kill microorganisms for decades but is carcinogenic and cataractogenic, recent evidence has shown that far-UVC is safe to use around humans. A high-fidelity, fully-coupled radiation transport and fluid dynamics model has been developed to quantify disinfection rates within a typical ventilated room. The model shows that disinfection rates are increased by a further 50-85% when using far-UVC within currently recommended exposure levels compared to the rooms’ ventilation alone. With these magnitudes of reduction, far-UVC lighting could be employed to mitigate SARS-CoV-2 transmission before the onset of future waves, or the start of winter when risks of infection are higher. This is particularly significant in poorly-ventilated spaces where other means of reduction are not practical, in addition social distancing can be decreased without increasing the risk

    Understanding Class-level Testability Through Dynamic Analysis

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    It is generally acknowledged that software testing is both challenging and time-consuming. Understanding the factors that may positively or negatively affect testing effort will point to possibilities for reducing this effort. Consequently there is a significant body of research that has investigated relationships between static code properties and testability. The work reported in this paper complements this body of research by providing an empirical evaluation of the degree of association between runtime properties and class-level testability in object-oriented (OO) systems. The motivation for the use of dynamic code properties comes from the success of such metrics in providing a more complete insight into the multiple dimensions of software quality. In particular, we investigate the potential relationships between the runtime characteristics of production code, represented by Dynamic Coupling and Key Classes, and internal class-level testability. Testability of a class is consider ed here at the level of unit tests and two different measures are used to characterise those unit tests. The selected measures relate to test scope and structure: one is intended to measure the unit test size, represented by test lines of code, and the other is designed to reflect the intended design, represented by the number of test cases. In this research we found that Dynamic Coupling and Key Classes have significant correlations with class-level testability measures. We therefore suggest that these properties could be used as indicators of class-level testability. These results enhance our current knowledge and should help researchers in the area to build on previous results regarding factors believed to be related to testability and testing. Our results should also benefit practitioners in future class testability planning and maintenance activities

    A Sailor’s Disease Presenting in Urban America with Red Spots on the Legs

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    Sailors were often affected by nutritional deficiencies due to the absence of fresh foods on long voyages. One example is the development of scurvy from a lack of vitamin C ingestion. In modern society in which fresh food are available this disease is infrequently recognized. The following case describes a 62-year-old male who presented with “red spots” on his legs and a large area of ecchymosis on his thigh. After initial testing failed to elicit a cause, a dietary history revealed that the patient had a peculiar diet of only ice cream with a total avoidance of fruits and vegetables. This case highlights the importance of a good history and physical examination as the basis for medical diagnosis

    What difference does ("good") HRM make?

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    The importance of human resources management (HRM) to the success or failure of health system performance has, until recently, been generally overlooked. In recent years it has been increasingly recognised that getting HR policy and management "right" has to be at the core of any sustainable solution to health system performance. In comparison to the evidence base on health care reform-related issues of health system finance and appropriate purchaser/provider incentive structures, there is very limited information on the HRM dimension or its impact. Despite the limited, but growing, evidence base on the impact of HRM on organisational performance in other sectors, there have been relatively few attempts to assess the implications of this evidence for the health sector. This paper examines this broader evidence base on HRM in other sectors and examines some of the underlying issues related to "good" HRM in the health sector. The paper considers how human resource management (HRM) has been defined and evaluated in other sectors. Essentially there are two sub-themes: how have HRM interventions been defined? and how have the effects of these interventions been measured in order to identify which interventions are most effective? In other words, what is "good" HRM? The paper argues that it is not only the organisational context that differentiates the health sector from many other sectors, in terms of HRM. Many of the measures of organisational performance are also unique. "Performance" in the health sector can be fully assessed only by means of indicators that are sector-specific. These can focus on measures of clinical activity or workload (e.g. staff per occupied bed, or patient acuity measures), on measures of output (e.g. number of patients treated) or, less frequently, on measures of outcome (e.g. mortality rates or rate of post-surgery complications). The paper also stresses the need for a "fit" between the HRM approach and the organisational characteristics, context and priorities, and for recognition that so-called "bundles" of linked and coordinated HRM interventions will be more likely to achieve sustained improvements in organisational performance than single or uncoordinated interventions

    What are the priorities for improving cataract surgical outcomes in Africa? Results of a Delphi exercise.

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    PURPOSE: The quality of cataract surgery delivered in sub-Saharan Africa (SSA) is a significant constraint to achieving the elimination of avoidable blindness. No published reports from routine SSA cataract services attain the WHO benchmarks for visual outcomes; poor outcomes (<6/60) often comprise 20% in published case series. This Delphi exercise aimed to identify and prioritise potential interventions for improving the quality of cataract surgery in SSA to guide research and eye health programme development. METHODS: An initial email open-question survey created a ranked list of priorities for improving quality of surgical services. A second-round face-to-face discussion facilitated at a Vision 2020 Research Mentorship Workshop in Tanzania created a refined list for repeated ranking. RESULTS: Seventeen factors were agreed that might form target interventions to promote quality of cataract services. Improved training of surgeons was the top-ranked item, followed by utilisation of biometry, surgical equipment availability, effective monitoring of outcomes of cataract surgery by the surgeon, and well-trained support staff for the cataract pathway (including nurses seeing post-operative cases). CONCLUSION: Improving the quality of cataract surgery in SSA is a clinical, programmatic and public health priority. In the absence of other evidence, the collective expert opinion of those involved in ophthalmic services regarding the ranking of factors to promote quality improvement, refined through this Delphi exercise, provides us with candidate intervention areas to be evaluated

    A Transformative Approach to Incorporating Adaptive Courseware: Strategic Implementation, Backward Design and Research-based Teaching Practices

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    In July 2016, Colorado State University (CSU) joined seven other land-grant institutions in the Accelerating Adoption of Adaptive Courseware grant sponsored by the Personalized Learning Consortium (PLC) of the Association of Public and Land-grant Universities (APLU). A primary objective of the grant was to scale the adoption of adaptive courseware in general education courses at each of the grant institutions. CSU targeted high-enrollment, general education courses and took a three-pronged, transformative approach to the integration of adaptive courseware. Specifically, CSU divided the courseware integration into three components: 1) strategic implementation of courseware, 2) backward course design, and 3) incorporation of research-based teaching practices. By May 2020, it is projected that over 40,000 students will have taken courses that were developed in this manner. Faculty participating in the grant completed the Teaching Practices Inventory (TPI) developed by the Wieman Institute. The inventory measures the extent to which instructors use research-based teaching practices (ETP). Faculty use of research-based teaching practices in strategic alignment with active learning and adaptive courseware provided the greatest measure of success. In general, instructors with ETP scores above 24 had higher course success rates than those with lower ETP scores. However, these differences were statistically significant for instructors of STEM courses with ETP scores of 30 and higher. Data indicates that simply adding adaptive courseware is not enough to impact student success. It is the combination of: 1) strategic implementation of courseware, 2) backward course design, and 3) the incorporation of research-based teaching practices that has the most potential to impact student success
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