453 research outputs found

    A study of the understanding of knowledge and learning of a cohort of mature age students

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    In 2005 the authors began a longitudinal research project to explore the factors that influence student success in the Master of Engineering Practice program which was offered for the first time in Semester 2, 2004. This distance education program enables experienced Engineering Technologists to use their workplace learning to gain a qualification at the Professional Engineer level. This research was initiated because the admission of some students into the program is based on the recognition of their prior workplace learning. Cantwell and Scevak (2004) highlighted the problems that students may encounter when they gain entry to a university on this basis. To explore this issue four previously validated questionnaires were used to gather data on: student approaches to learning, their epistemological beliefs, learning style preferences, and strategic flexibility. This paper reports on a preliminary analysis of the data gathered from the students who enrolled in the program during the period 2005-2009. In the longer term, when the sample size has grown and more students have graduated, the data will be analysed to explore the relationship between the measured factors and success at university

    The Use of Open Communal Grazing Designs to Screen Options for Grazing Management

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    An open communal grazing design is described that enables a large number of grazing tactics to be concurrently evaluated in small plots under common grazing conditions. Pasture data indicated that the same level of utilisation occurred inside the experimental plots as in the surrounding field. However, differential grazing may occur where plots have divergent composition. The open communal design was economical using \u3c 5% of the land, livestock and fencing resources of alternative designs. The limitations of the open communal design as a research tool are also discussed

    The Analysis of Results from Paired Paddock Comparisons

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    Paired-paddock comparisons are a common way of evaluating new grassland practices at a scale more relevant to farmers. They are also being used to replace or augment designed experiments and can be the only source of information available on a practice. However, it is often uncertain if the differences between paddocks are significant. Importantly, a current trend among funding organisations is to support paddock comparisons. The need for valid procedures to compare unreplicated treatments is increasingly urgent. It is suggested that a range of tools be used to infer statistical significance from using typical error values from related studies or subsampling, through to multivariate techniques to follow trends. Local ‘rules of thumb’ could be developed and data evaluated with calibrated models. A final judgement on treatment effects would need to be based upon the use of several criteria to achieve a ‘balance of probabilities’. Consideration of these problems suggests that paired-paddocks should only be used to evaluate contrasting treatments where large effects are expected and not small variations within a practice

    High Reynolds-Number Assessment of a Multifractal Subgrid-Scale Model

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77107/1/AIAA-2002-2961-570.pd

    Significant Phonon Drag Enables High Power Factor in the AlGaN/GaN Two-Dimensional Electron Gas

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    In typical thermoelectric energy harvesters and sensors, the Seebeck effect is caused by diffusion of electrons or holes in a temperature gradient. However, the Seebeck effect can also have a phonon drag component, due to momentum exchange between charge carriers and lattice phonons, which is more difficult to quantify. Here, we present the first study of phonon drag in the AlGaN/GaN two-dimensional electron gas (2DEG). We find that phonon drag does not contribute significantly to the thermoelectric behavior of devices with ~100 nm GaN thickness, which suppress the phonon mean free path. However, when the thickness is increased to ~1.2 μ\mum, up to 32% (88%) of the Seebeck coefficient at 300 K (50 K) can be attributed to the drag component. In turn, the phonon drag enables state-of-the-art thermoelectric power factor in the thicker GaN film, up to ~40 mW m−1^{-1} K−2^{-2} at 50 K. By measuring the thermal conductivity of these AlGaN/GaN films, we show that the magnitude of the phonon drag can increase even when the thermal conductivity decreases. Decoupling of thermal conductivity and Seebeck coefficient could enable important advancements in thermoelectric power conversion with devices based on 2DEGs

    Checklist of Bees (Hymenoptera: Apoidea) From Managed Emergent Wetlands in the Lower Mississippi Alluvial Valley of Arkansas

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    Background Here we present the results from a two-year bee survey conducted on 18 managed emergent wetlands in the lower Mississippi Alluvial Valley of Arkansas, USA. Sample methods included pan traps, sweep netting and blue-vane traps. We document 83 bee species and morphospecies in 5 families and 31 genera, of which 37 species represent first published state records for Arkansas. The majority of species were opportunistic wetland species; only a small number were wetland-dependent species or species largely restricted to alluvial plains. New information We present new distributional records for bee species not previously recorded in managed emergent wetlands and report specimens of thirty-seven species for which no published Arkansas records exist, expanding the known ranges of Ceratina cockerelli, Diadasia enavata, Lasioglossum creberrimum, Svastracressonii and Dieunomia triangulifera. We also distinguish opportunistic wetland bee species from wetland-dependent and alluvial plain-restricted species

    High-sensitivity photoacoustic leak testing

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    A Latent Class Binomial Logit Methodology for the Analysis of Paired Comparison Choice Data

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    A latent class model for identifying classes of subjects in paired comparison choice experiments is developed. The model simultaneously estimates a probabilistic classification of subjects and the logit models' coefficients relating characteristics of objects to choices for each respective group among two alternatives in paired comparison experiments. A modest Monte Carlo analysis of algorithm performance is presented. The proposed model is illustrated with empirical data from a consumer psychology experiment that examines the determinants of perceived consumer risk. The predictive validity of the method is assessed and compared to that of several other procedures. The sensitivity of the method to (randomly) eliminate comparisons, which is important in view of reducing respondent fatigue in the task, is investigated.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74931/1/j.1540-5915.1993.tb00508.x.pd

    Preventing the Reintroduction of Malaria in Mauritius: A Programmatic and Financial Assessment

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    Sustaining elimination of malaria in areas with high receptivity and vulnerability will require effective strategies to prevent reestablishment of local transmission, yet there is a dearth of evidence about this phase. Mauritius offers a uniquely informative history, with elimination of local transmission in 1969, re-emergence in 1975, and second elimination in 1998. Towards this end, Mauritius's elimination and prevention of reintroduction (POR) programs were analyzed via a comprehensive review of literature and government documents, supplemented by program observation and interviews with policy makers and program personnel. The impact of the country's most costly intervention, a passenger screening program, was assessed quantitatively using simulation modeling
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