794 research outputs found

    Viral diseases of the eye.

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    Defining a rhombus

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    Colin Foster, Jeremy Hodgen and Dietmar Kuchemann exlore how the use of examples and counter-examples can support students developing understandings of definitions

    Crozier's Effect and the Acceptance of Intraspecific Brood Parasites.

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    Organisms can often benefit by distinguishing between different classes of individuals. An example is kin recognition, whereby individuals preferentially associate with or aid genetic relatives that bear matching recognition cues but reject others. Despite its potential benefits, however, kin recognition using genetically based cues is often weak or absent [1-4]. A general explanation, termed "Crozier's effect," is that when individuals interact randomly, rarer cue alleles less often match cues of other individuals, and so are involved predominantly in "reject"-type interactions. If such interactions are more costly, positive frequency-dependent selection will erode the cue diversity upon which discrimination depends [4, 5]. Although widely cited [1, 2, 4, 6-9], this idea lacks rigorous testing in the field. Here, we show how Crozier's effect applies to interactions between hosts and conspecific parasites, and measure it using field data. In the wasp we studied, conspecific parasitism fits a key assumption of Crozier's model: the same females act as both hosts and parasites. By exchanging offspring between nests experimentally, we find no evidence that females respond to genetically based cues associated with foreign offspring. Through measuring costs and benefits, however, we demonstrate a strong Crozier effect: because more parental investment is wasted when foreign offspring are rejected, interactions involving rejection have substantially lower payoffs than interactions involving acceptance. Costly rejection can thus eliminate cue diversity by causing selection against rare cue alleles, consistent with the absence of genetically based recognition that we observe. Females instead appear to rely on non-genetic cues that enable them to detect less than half of parasitic offspring

    Variable selection in monotone single‐index models via the adaptive LASSO

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    We consider the problem of variable selection for monotone single‐index models. A single‐index model assumes that the expectation of the outcome is an unknown function of a linear combination of covariates. Assuming monotonicity of the unknown function is often reasonable and allows for more straightforward inference. We present an adaptive LASSO penalized least squares approach to estimating the index parameter and the unknown function in these models for continuous outcome. Monotone function estimates are achieved using the pooled adjacent violators algorithm, followed by kernel regression. In the iterative estimation process, a linear approximation to the unknown function is used, therefore reducing the situation to that of linear regression and allowing for the use of standard LASSO algorithms, such as coordinate descent. Results of a simulation study indicate that the proposed methods perform well under a variety of circumstances and that an assumption of monotonicity, when appropriate, noticeably improves performance. The proposed methods are applied to data from a randomized clinical trial for the treatment of a critical illness in the intensive care unit. Copyright © 2013 John Wiley & Sons, Ltd.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/100172/1/sim5834.pd

    Augmented Reality in Medical Education:A Mixed Methods Feasibility Study

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    Background: Augmented reality (AR) is a novel technology with many applications in medical education. Perhaps one of the most beneficial potential applications is to enable better clinical access for students; however, there is limited research into this use. The purpose of this mixed-methods feasibility study was to evaluate the applicability and acceptability of AR in undergraduate and early postgraduate medical education.Methods: Single-group quasi-experimental study design was developed for critical care-themed simulation teaching delivered using Microsoft HoloLens (Microsoft Corporation, Redmond, Washington, United States). Post-test questionnaires were completed including a validated adapted immersive experience questionnaire (AIEQ) and an abridged intrinsic motivation inventory (AIMI). The AIMI focused on the domains of ‘interest and enjoyment’, and ‘value and usefulness’. Following the teaching, focus group interviews with thematic analysis were conducted to evaluate participants’ experiences with AR.Results: All 15 participants (100%) completed the AIEQ and AIMI. Co-located airway teaching (i.e., the demonstrator and participants were placed in the same AR environment) was reported as having a moderate level of user immersion (median 72) and a high level of user enjoyment and value (median 52). Thematic analysis revealed four key themes: visual conceptualization for learning, accessibility, varied immersion, and future application. Conclusions: Remote simulation for the management of airways in critical care was found to be acceptable and afforded a high level of enjoyment and value. Similarly, this was reflected in the thematic analysis. However, immersion was rated variably in both AIEQ and thematic analysis. The challenges identified with the application of AR included technical infrastructure and patient consent. AR-enabled education benefits are relevant to a number of clinical teaching areas

    Improving mathematics in key stages two and three:evidence review

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    This document presents a review of evidence commissioned by the Education Endowment Foundation to inform the guidance document Improving Mathematics in Key Stages Two and Three (Education Endowment Foundation, 2017). There have been a number of recent narrative and systematic reviews of mathematics education examining how students learn and the implications for teaching (e.g., Anthony & Walshaw, 2009; Conway, 2005; Kilpatrick et al., 2001; Nunes et al., 2010). Although this review builds on these studies, this review has a different purpose and takes a different methodological approach to reviewing and synthesising the literature. The purpose of the review is to synthesise the best available international evidence regarding teaching mathematics to children between the ages of 9 and 14 and to address the question: what is the evidence regarding the effectiveness of different strategies for teaching mathematics? In addition to this broad research question, we were asked to address a set of more detailed topics developed by a group of teachers and related to aspects of pupil learning, pedagogy, the use of resources, the teaching of specific mathematical content, and pupil attitudes and motivation. Using these topics, we derived the 24 research questions that we address in this review. Our aim was to focus primarily on robust, causal evidence of impact, using experimental and quasi-experimental designs. However, there are a very large number of experimental studies relevant to this research question. Hence, rather than identifying and synthesising all these primary studies, we focused instead on working with existing meta-analyses and systematic reviews. This approach has the advantage that we can draw on the findings of a very extensive set of original studies that have already been screened for research quality and undergone some synthesis. Using a systematic literature search strategy, we identified 66 relevant meta-analyses, which synthesise the findings of more than 3000 original studies. However, whilst this corpus of literature is very extensive, there were nevertheless significant gaps. For example, the evidence concerning the teaching of specific mathematical content and topics was limited. In order to address gaps in the meta-analytic literature, we supplemented our main dataset with 22 systematic reviews identified through the same systematic search strategy

    Pendokumentasian Aplikasi Ragam Hias Budaya Bali, sebagai Upaya Konservasi Budaya Bangsa Khususnya pada Perancangan Interior

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    Various ornament of Indonesian people comes from the ethnic groups from all over the archipelago. As a tangible cultural ornament has a specific purpose and it does not change throughout the ages. Bali is one of the ethnic group in archipelago that has beautiful decorative art and one of the most popular tourism destination in Indonesia. Bali\u27s ornament generally seen as decorative carving on the column, window or even in door. The beauty of Bali is not only as an inspiration for their colors and sculpture but also the variety of forms that have been simplified in the ornament. Moreover, floral & fauna forms are easy to apply as an interior element in modern buildings. Generally the value of these ornament has a specific purpose related to the cultural and social custom in Bali people. So that the application need to consider more about the purpose of the symbol of the ornament

    Monitoring Training Load Using the Acute: Chronic Workload Ratio in Non-Elite Intercollegiate Female Athletes

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    Monitoring training load and its progression in athletes is important to optimise adaptations to training while simultaneously preventing injury. A recent development in this field is the acute: chronic workload ratio (ACWR), which track s average acute training load against average chronic training load to describe training load progression. Furthermore, a new method of calculating the ACWR has been developed using exponentially weighted moving averages (EWMA) which accounts for the decay of fitness and fatigue. This study sought to investigate the relationship between the EWMA and ACWR (based upon session rating of perceived exertion (sRPE)), and injury risk in intercollegiate female athletes (N=4). Participants performed adductor squeeze tests (ASTs) once a week for 8 week s, while their training and wel lness were monitored with sRPE and a daily questionnaire respectively. A hierarchical regression demonstrated that monitoring of average sleep length, average stress, sRPE work loads and an EWMA provided the best model for predicting injury risk in athletes (R2 = 0.47). The findings indicate that the EWMA may be a effective training load monitoring tool than the ACWR model

    Hands-On Learning Environment and Educational Curriculum on Collaborative Robotics

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    The objective of this paper is to describe teaching modules developed at Wayne State University integrate collaborative robots into existing industrial automation curricula. This is in alignment with Oakland Community College and WSU’s desire to create the first industry-relevant learning program for the use of emerging collaborative robotics technology in advanced manufacturing systems. The various learning program components will prepare a career-ready workforce, train industry professionals, and educate academicians on new technologies. Preparing future engineers to work in highly automated production, requires proper education and training in CoBot theory and applications. Engineering and Engineering Technology at Wayne State University offer different robotics and mechatronics courses, but currently there is not any course on CoBot theory and applications. To follow the industry needs, a CoBot learning environment program is developed, which involves theory and hands-on laboratory exercises in order to solve many important automaton problems. This material has been divided into 5-modules: (1) Introduce the concepts of collaborative robotics, (2) Collaborative robot mechanisms and controls, (3) Safety considerations for collaborative robotics, (4) Collaborative robot operations and programming, (5) Collaborative robot kinematics and validation. These modules cover fundamental knowledge of CoBots in advanced manufacturing systems technology. Module content has been developed based on input and materials provided by CoBot manufacturers. After completing all modules students must submit a comprehensive engineering report to document all requirements

    Underground mining of aggregates. Main report

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    This report examines the economic feasibility of underground mining for crushed rock aggregates in the UK, but particularly in the London, South East and East of England regions (the South East area of England). These regions import substantial volumes of crushed rock, primarily from the East Midlands and South West regions, requiring relatively long transport distances to market for this bulk commodity. A key part of the research was to determine whether or not aggregate could be produced and delivered to a local market from an underground aggregates operation at a cost comparable with that for production and transport of the commodity from traditional surface quarries located further afield. In essence the investigation asked – could the reduced transport costs compensate for the higher production costs underground so that underground crushed rock aggregates producers can compete with the established Leicestershire and Somerset surface quarries exporting to the South East? Work Programme The research effort involved establishing and verifying cost models for aggregates production, stone processing (sizing and sorting), haulage of product to market, environmental impact mitigation, health and safety, decommissioning and restoration. Another major element of the work was the re-examination of the BGS exploratory borehole and geophysical databases to identify potential areas of crushed rock aggregates resource at depth in the South East area of England. Land use pressure is typically higher in this area of England than elsewhere so another major part of the research was the identification of potential concurrent uses of land around the surface facilities of underground aggregates mines. The value, development costs for specific developments and determination of yields expected, from these uses were estimated. These were also used to investigate potential economic benefits associated with after uses of remediated surface land above potential underground aggregates mines and also for the new underground space that would be created. Key technical issues such as subsidence within relatively heavily populated areas of the South East area of England were also addressed. Economic Results The discounted cost of aggregate delivered at a discount rate of 10% was the metric used to appraise the options. This is the price of aggregate that leads to a zero net present value of project cash flows realised over the aggregates project life. The results show that the discounted costs of aggregate delivered to a local South East area of England market from an underground mine producing 3.5 million tonnes per annum (MTPA) of crushed rock aggregates, are in the range of £13.03 per tonne to £13.93 per tonne for the top six prospect locations. These are greater than the corresponding cost for a “reference” quarry in Leicestershire producing 3.5 MTPA (£10.95 per tonne), but lower than a “reference” quarry in Leicestershire producing 1.25 MTPA (£16.48 per tonne). These figures indicate that underground crushed rock aggregate mines located within the South East area of England may be able to compete for a share in the overall market by replacing / displacing aggregate imported from the quarries in Leicestershire and Somerset producing around or less than 1.25 MTPA. The surprise in these figures is not really that the more remote surface quarry has a lower discounted cost of aggregate delivered, but that the values for the quarry and underground mine are so close. The capital intensity for the development of underground aggregates mines was found to be higher than that required for surface quarries of comparable scale, by a factor ranging from 1.33 to 1.65 and thus may represent a disincentive for aggregates operators. Carbon Emissions The total carbon emissions of the ‘reference’ 3.5 MTPA quarry in Leicestershire were estimated at 9.28 kg CO2/tonne aggregate delivered and this is to be compared with carbon emissions for the 150 metre deep underground mines serving the local market which were estimated at 9.31 kg CO2/tonne delivered for a Bletchley prospect using an adit to access the sub-surface and 14.25 kg CO2/tonne delivered for a prospect based on the Chitty bore hole using a shaft. Depth of the mine is a key factor in determination of the relative carbon emissions from each of the underground mining operations considered as electricity consumption for ventilation, pumping and winding is proportional to depth. Recommendations The current research generated seven principal recommendations which are discussed in detail in the concluding section of the report. These are: Appraise policy incentives for underground aggregates mining. Conduct an industry-wide consultation on findings from the current research. Obtain public and stakeholder opinion on new uses for underground space. Conduct research to reducing the energy intensity of mine services. Develop a deep level aggregates-specific drilling campaign. Investigate underground aggregates mines developed from existing surface quarries. Investigate underground aggregates as co-products of industrial minerals mining
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