4,365 research outputs found

    A description of the soils and geology of the Berkshire Valley experimental catchment

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    Basic land resource data are provided in this report to assist an investigation of the effect of contour banking on surface runoff in the Berkshire Valley experimental catchement. Brief descriptions of the catchment\u27s geology, soils and their inferred hydrological significance are provided and a 1:2000 scale map produced. Of major significance to the hydrologic study is the fact that soil depth and internal drainage conditions were found to be not related to landscape positions

    A Game Theoretic Approach to assessing Additive Manufacturing as a Strategic Choice

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    Coulomb interactions in single, charged self-assembled quantum dots: radiative lifetime and recombination energy

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    We present results on the charge dependence of the radiative recombination lifetime, Tau, and the emission energy of excitons confined to single self-assembled InGaAs quantum dots. There are significant dot-to-dot fluctuations in the lifetimes for a particular emission energy. To reach general conclusions, we present the statistical behavior by analyzing data recorded on a large number of individual quantum dots. Exciton charge is controlled with extremely high fidelity through an n-type field effect structure, providing access to the neutral exciton (X0), the biexciton (2X0) and the positively (X1+) and negatively (X1-) charged excitons. We find significant differences in the recombination lifetime of each exciton such that, on average, Tau(X1-) / Tau(X0) = 1.25, Tau(X1+) / Tau(X0) = 1.58 and Tau(2X0) / Tau(X0) = 0.65. We attribute the change in lifetime to significant changes in the single particle hole wave function on charging the dot, an effect more pronounced on charging X0 with a single hole than with a single electron. We verify this interpretation by recasting the experimental data on exciton energies in terms of Coulomb energies. We show directly that the electron-hole Coulomb energy is charge dependent, reducing in value by 5-10% in the presence of an additional electron, and that the electron-electron and hole-hole Coulomb energies are almost equal.Comment: 8 pages, 7 figures, submitted to Phys. Rev.

    An inquiry-based learning approach to teaching information retrieval

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    The study of information retrieval (IR) has increased in interest and importance with the explosive growth of online information in recent years. Learning about IR within formal courses of study enables users of search engines to use them more knowledgeably and effectively, while providing the starting point for the explorations of new researchers into novel search technologies. Although IR can be taught in a traditional manner of formal classroom instruction with students being led through the details of the subject and expected to reproduce this in assessment, the nature of IR as a topic makes it an ideal subject for inquiry-based learning approaches to teaching. In an inquiry-based learning approach students are introduced to the principles of a subject and then encouraged to develop their understanding by solving structured or open problems. Working through solutions in subsequent class discussions enables students to appreciate the availability of alternative solutions as proposed by their classmates. Following this approach students not only learn the details of IR techniques, but significantly, naturally learn to apply them in solution of problems. In doing this they not only gain an appreciation of alternative solutions to a problem, but also how to assess their relative strengths and weaknesses. Developing confidence and skills in problem solving enables student assessment to be structured around solution of problems. Thus students can be assessed on the basis of their understanding and ability to apply techniques, rather simply their skill at reciting facts. This has the additional benefit of encouraging general problem solving skills which can be of benefit in other subjects. This approach to teaching IR was successfully implemented in an undergraduate module where students were assessed in a written examination exploring their knowledge and understanding of the principles of IR and their ability to apply them to solving problems, and a written assignment based on developing an individual research proposal

    The divergence of theoretical and actual designs in a holonic packing cell

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    The aim of this paper is to take the reader through the decisions made in designing a holonic system architecture to support customised packing of gift boxes with personal grooming (Gillette) products. The paper highlights issues that cause a divergence between a theoretical model of a holonic system and the approach that was actually encoded

    Modelling food sourcing decisions under climate change: A data-driven approach

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    Changes in climate conditions are expected to pose signi cant challenges to the food industry, as it is very likely that they will a ect the production of various crops. As a consequence, decisions associated with the sourcing of food items will need to be reconsidered in the years to come. In this paper, we investigate how environmental changes are likely to a ect the suitability and risk of di erent regions |in terms of growing certain food items| and whether companies should adapt their sourcing decisions due to these changes. In particular, we propose a three-stage approach that guides food sourcing decisions by incorporating climate change data. The methodology utilises environmental data from several publicly available databases and models weather uncertainties to calculate the suitability and risk indices associated with growing a crop in a particular geographical area. The estimated suitability and risk parameters are used in a mean-variance analysis to calculate the optimal sourcing decision. Results from a case example indicate that sourcing decisions of popular food items are likely to require signi cant adaptations due to changes to the suitability of certain regions

    The role of site and severity of injury as predictors of mental health outcomes following traumatic injury

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    The aim of this study was to investigate the influence of injury site and severity as predictors of mental health outcomes in the initial 12 months following traumatic injury. Using a multisite, longitudinal study, articipants with a traumatic physical injury (N = 1,098) were assessed during hospital admission and followed up at 3 months (N = 932, 86%) and at 12 months (N = 715, 71%). Injury site was measured using the abbreviated Injury Scale 90, and objective injury severity was measured using the Injury Severity Score. Participants also completed the Hospital Anxiety and Depression Scale and the Clinician Administered Post-traumatic Stress Disorder (PTSD) Scale. A random intercept mixed modelling analysis was conducted to evaluate the effects of site and severity of injury in relation to anxiety, PTSD, and depressive symptoms. Injury severity, as well as head and facial injuries, was predictive of elevated PTSD symptoms, and external injuries were associated with both PTSD and depression severity. In contrast, lower extremity injuries were associated with depresssive and anxiety symptoms. The findings suggest that visible injuries are predictive of reduced mental health, particularly PTSD following traumatic injury. This has clinical implications for further advancing the screening for vulnerable injured trauma survivors at risk of chronic psychopathology.Katharine Baecher, Maria Kangas, Alan Taylor, Meaghan L. O'Donnell, Richard A. Bryant, Derrick Silove, Alexander C. McFarlane, Darryl Wad
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