1,600 research outputs found

    Effective scraping in a scraped surface heat exchanger: some fluid flow analysis

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    An outline of mathematical models that have been used to understand the behaviour of scraped surface heat exchangers is presented. In particular the problem of the wear of the blades is considered. A simple model, exploiting known behaviour of viscous flow in corners and in wedges, and accounting for the forces on the blade is derived and solutions generated. The results shows initial rapid wear but that the wear rate goes to zero

    On- and Off-Farm Labour Suplly of Dutch Dairy Farmers: Estimation and Policy Simulations

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    This research focuses on the effect of decoupled payments on labour supply of Dutch dairy farmers. Data availability leads to the fact that we can not estimate structural labour supply equations. We show how to derive reduced form equations suitable for policy simulations. We use the panel data sample selection estimation approach Wooldridge (1995) to estimate the off-farm labour supply equation. This method is based on Mundlak¿s (1978) linear panel data estimation approach, which we us to estimate the on-farm labour supply equations. Even though, simulations show a significant negative effect of decoupled payments on labour supply, the economic significance of this effect is very limited

    EU policy reform simulation based on panel data estimation of on- and off-farm labour supply equations for Dutch dairy farmers

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    This research focuses on the estimation of labour supply equations for Dutch dairy farmers that are suitable for policy simulations. Data availability leads to the fact that we can not estimate structural labour supply equations. We show how to derive reduced form equations suitable for policy simulations. In this research we use the panel data sample selection estimation approach of Kyriazidou (1997) and Wooldridge (1995) to estimate the off-farm labour supply equation. The two lead to different estimation results and different simulation results based on these

    Suggestion, hypnosis and hypnotherapy: a survey of use, knowledge and attitudes of anaesthetists

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    Publisher's copy made available with the permission of the publisher © Australian Society of AnaesthetistsClinical hypnosis is a skill of using words and gestures (frequently called suggestions) in particular ways to achieve specific outcomes. It is being increasingly recognised as a useful intervention for managing a range of symptoms, especially pain and anxiety. We surveyed all 317 South Australian Fellows and trainees registered with ANZCA to determine their use, knowledge of, and attitudes towards positive suggestion, hypnosis and hypnotherapy in their anaesthesia practice. The response rate was 218 anaesthetists (69%). The majority of respondents (63%) rated their level of knowledge on this topic as below average. Forty-eight per cent of respondents indicated that there was a role for hypnotherapy in clinical anaesthesia, particularly in areas seen as traditional targets for the modality, i.e. pain and anxiety states. Nearly half of the anaesthetists supported the use of hypnotherapy and positive suggestions within clinical anaesthesia. Those respondents who had experience of clinical hypnotherapy were more likely to support hypnosis teaching at undergraduate or postgraduate level when compared with those with no experience.http://www.aaic.net.au/Article.asp?D=200408

    Split vortices in optically coupled Bose-Einstein condensates

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    We study a rotating two-component Bose-Einstein condensate in which an optically induced Josephson coupling allows for population transfer between the two species. In a regime where separation of species is favored, the ground state of the rotating system displays domain walls with velocity fields normal to them. Such a configuration looks like a vortex split into two halves, with atoms circulating around the vortex and changing their internal state in a continuous way.Comment: 4 EPS pictures, 4 pages; Some errata have been corrected and thep resentation has been slightly revise

    Toward an Integrated Competence-based System Supporting Lifelong Learning and Employability: Concepts, Model, and Challenges

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    Miao, Y., Van der Klink, M., Boon, J., Sloep, P. B., & Koper, R. (2009). Toward an Integrated Competence-based System Supporting Lifelong Learning and Employability: Concepts, Model, and Challenges. In M. Spaniol, Q. Li, R. Klamma & R. W. H. Lau (Eds.), Proceedings of the 8th International Conference Advances in Web Based Learning - ICWL 2009 (pp. 265-276). August, 19-21, 2009, Aachen, Germany. Lecture Notes in Computer Science 5686; Berlin, Heidelberg: Springer-Verlag.Efficient and effective lifelong learning requires that people can make informed decisions about their continuous personal development in the different stages of their lives. In this paper we state that lifelong learners need to be characterized as decision-makers. In order to improve the quality of their decisions we propose the development of an integrated lifelong learning and employment support system, which traces learners’ competence development and provides a decision support environment. An abstract conceptual model has been developed and the main design ideas have been documented using Z notation. Moreover, we analyzed the main technical challenges for the realization of the target system: competence information fusion, decision analysis models, spatial indexing structures and browsing structures and visualization of competence related information objects.The work on this publication has been sponsored by the TENCompetence Integrated Project that is funded by the European Commission's 6th Framework Programme, priority IST/Technology Enhanced Learning. Contract 027087 [http://www.tencompetence.org

    Analyzing Powers for Deuteron-Induced Reactions Leading to Continuum Final States

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    This work was supported by the National Science Foundation Grant NSF PHY 78-22774 A02 & A03 and by Indiana Universit

    Life at the extreme:Plant-driven hotspots of soil nutrient cycling in the hyper-arid core of the Atacama Desert

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    The hyperarid core of the Atacama Desert represents one of the most intense environments on Earth, often being used as an analog for Mars regolith. The area is characterized by extremes in climate (e.g., temperature, humidity, UV irradiation) and edaphic factors (e.g., hyper-salinity, high pH, compaction, high perchlorates, and low moisture, phosphorus and organic matter). However, the halophytic C4 plant Distichlis spicata appears to be one of the few species on the planet that can thrive in this environment. Within this habitat it captures windblown sand leading to the formation of unique structures and the generation of above-ground phyllosphere soil. Using a combination of approaches (e.g., X-ray Computed Tomography, TXRF, δ13C/δ15N isotope profiling, microbial PLFAs, 14C turnover, phosphate sorption isotherms) we examined the factors regulating the biogeochemical cycling of nitrogen (N), phosphorus (P) and carbon (C) in both vegetated and unvegetated areas. Our results showed that D. spicata rhizomes with large aerenchyma were able to break through the highly cemented topsoil layer leading to root proliferation in the underlying soil. The presence of roots increased soil water content, P availability and induced a change in microbial community structure and promoted microbial growth and activity. In contrast, soil in the phyllosphere exhibited almost no biological activity. Organic C stocks and recent C4 plant derived input increased as follows: phyllosphere (1941 g C m−2; 85% recent) &gt; soils under plants (575–748 g C m−2; 55–60%) &gt; bare soils (491–642 g C m−2; 9–17%). Due to the high levels of nitrate in soil (&gt;2 t ha−1) and high rates of P sorption/precipitation, our data suggest that the microbial activity is both C and P, but not N limited. Root-mediated salt uptake combined with foliar excretion and dispersal of NaCl into the surrounding area indicated that D. spicata was responsible for actively removing ca. 55% of the salt from the rhizosphere. We also demonstrate that NH3 emissions may represent a major N loss pathway from these soil ecosystems during the processing of organic N. We attribute this to NH3 volatilization to the high pH of the soil and slow rates of nitrification. In conclusion, we demonstrate that the extremophile D. spicata physically, chemically and biologically reengineers the soil to create a highly bioactive hotspot within the climate-extreme of the Atacama Desert.</p

    Reaction Mechanism Implications of Deuteron Rainbow Scattering

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    This work was supported by the National Science Foundation Grant NSF PHY 78-22774 A02 & A03 and by Indiana Universit

    Measurements of X_2 and Other Results in the Analysis of d + 58-Ni Elastic Scattering

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    This work was supported by the National Science Foundation Grants NSF PHY 78-22774 A03, NSF PHY 81-14339, and by Indiana Universit
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