2,820 research outputs found

    Thermodynamics of Coarse Grained Models of Super-Cooled Liquids

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    In recent papers, we have argued that kinetically constrained coarse grained models can be applied to understand dynamic properties of glass forming materials, and we have used this approach in various applications that appear to validate this view. In one such paper [J.P. Garrahan and D. Chandler, Proc. Nat. Acad. Sci. USA 100, 9710 (2003)], among other things we argued that this approach also explains why the heat capacity discontinuity at the glass transition is generally larger for fragile materials than for strong materials. In the preceding article, Biroli, Bouchaud and Tarjus (BB&T) [cond-mat/0412024] have objected to our explanation on this point, arguing that the class of models we apply is inconsistent with both the absolute size and temperature dependence of the experimental specific heat. Their argument, however, neglects parameters associated with the coarse graining. Accounting for these parameters, we show here that our treatment of dynamics is not inconsistent with heat capacity discontinuities.Comment: 5 pages, 2 figures. Revised version to appear in J. Chem. Phy

    A comparison of theory and experiment for aeroelastic stability of a hingeless rotor model in hover

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    Theoretical predictions of aeroelastic stability are compared with experimental, isolated, hingeless-rotor data. The six cases selected represent a torsionally soft rotor having either a stiff or soft pitch-control system in combination with zero precone and droop, 5 degree precone, or -5 degree droop. Analyses from Bell Helicopter Textron, Boeing Vertol, Hughes Helicopters, Sikorsky Aircraft, the National Aeronautics and Space Administration, and the U.S. Army Aeromechanics Laboratory were compared with the experimental data. The correlation ranged from poor to fair

    Characterisation framework of key policy, regulatory and governance dynamics and impacts upon European food value chains: Fairer trading practices, food integrity, and sustainability collaborations. : VALUMICS project “Understanding Food Value Chains and Network Dynamics” funded by EU Horizon 2020 G.A. No 727243. Deliverable D3.3

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    The report provides a framework that categorises the different European Union (EU) policies, laws and governance actions identified as impacting upon food value chains in the defined areas of: fairer trading practices, food integrity (food safety and authenticity), and sustainability collaborations along food value chains. A four-stage framework is presented and illustrated with examples. The evidence shows that European Union policy activity impacting upon food value chain dynamics is increasing, both in terms of the impacts of policies upon the chains, and, in terms of addressing some of the more contentious outcomes of these dynamics. A number of policy priorities are at play in addressing the outcomes of food value chain dynamics. unevenness of the distribution of profit within food value chains, notably to farmers. Regulation of food safety and aspects of authenticity has been a key focus for two decades to ensure a functioning single market while ensuring consumer health and wellbeing. A food chain length perspective has been attempted, notably through regulations such as the General Food Law, and the rationalisation of the Official Controls on food and feed safety. However, there are still gaps in the effective monitoring and transparency of food safety and of food integrity along value chains, as exemplified by misleading claims and criminal fraud. This has led to renewed policy actions over food fraud, in particular. EU regulations, policies and related governance initiatives provide an important framework for national-level actions for EU member states and for EEA members. The more tightly EU-regulated areas, such as food safety, see fewer extra initiatives, but where there is a more general strategic policy and governance push, such as food waste reduction or food fraud, there is greater independent state-level activity. Likewise, there is much more variation in the application of both national and European (Competition) law to govern unfair trading practices impacting upon food value chains. This report presents the findings of a survey of members from the VALUMICS stakeholder platform, that were policy facing food value chain stakeholders across selected European countries, including both EU and EEA Member States. The survey was conducted to check the significance of the main policies identified in the mapping exercise at EU and national levels and so to incorporate the views of stakeholders in the research. The responses suggest the policy concerns identified in EU and national-level research resonate with food value chain stakeholders in participating nations. The report concludes by exploring in more detail how the themes of fairness and of transparency are being handled in the policy activities presented. Highlighted are the ways that both fairness and transparency can be extended within the existing frameworks of EU policy activity. The findings in this report provide an important context for further and detailed research analysis of the workings and dynamics of European food value chains under the VALUMICS project

    Heavy meson chiral perturbation theory in finite volume

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    We present the first step towards the estimation of finite volume effects in heavy-light meson systems using heavy meson chiral perturbation theory. We demonstrate that these effects can be amplified in both light-quark and heavy-quark mass extrapolations (interpolations) in lattice calculations. As an explicit example, we perform a one-loop calculation for the neutral B meson mixing system and show that finite volume effects, which can be comparable with currently quoted errors, are not negligible in both quenched and partially quenched QCD.Comment: Talk presented at Lattice2004(heavy), Fermilab, June 21st-26th, 2004. Three pages, two figure

    Where Are They Now? Migration Patterns for Graduates of the University of British Columbia

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    In an empirical analysis of the migration patterns of University of British Columbia (UBC) graduates, John F. and David F. Helliwell show in their paper how much the situation has changed between the 1960s and the 1990s. Canadian research and graduate education have expanded dramatically, leading many more undergraduates to stay in Canada for their graduate work. According to the Helliwells, this is perhaps the single most important reason why the south-bound flows of bachelor’s graduates has fallen so much from the early 1960s to the 1990s. Consequently, they argue that the resurgence of discussion of a brain drain in the 1990s has much less basis in the data, and probably represents factors specific to certain sectors, such as health spending, research and university financing, where funding support has risen much less rapidly than in the United States. It has also been fuelled to some extent by sharp increases in the numbers in temporary NAFTA visas to Canadians working in the United States, and in part to increasing gaps in salaries and tax rates in the 1990s that favoured high-income earners in the United States, relative to their Canadian counterparts. The UBC graduate data show that over the past five decades there have been continuing reductions in the shares of UBC graduates living in the United States. For all of the large-scale bachelor’s programs the proportion of graduates living in the United States has continued to fall during the 1990s. For the graduate programs, the proportion living outside Canada is and has always been high, reflecting a very international mix of both the student intake and the available career positions. For all degrees, the proportion of 1990s UBC graduates living in the rest of the world is higher than that in the United States. For graduate degrees, the proportion of the graduates subsequently living and working in Canada, and especially in British Columbia, is much higher than the share of Canadian citizens among the incoming students. With respect to the international distribution of those with the highest level of educational aptitude and attainments, as represented by the master’s and PhD graduates of UBC, Canada and British Columbia stand in the middle ground between the United States and the rest of the world. Comparing the citizenship of UBC’s graduate intake with the country of residence of the graduates, the United States is the largest proportionate net recipient (7 per cent U.S. citizen intake, 14 per cent U.S.-resident 1990s PhDs), Canada is the largest recipient in terms of numbers of PhDs (46 per cent Canadian citizen intake, 70 per cent Canadian-resident 1990s PhDs), with students from 100 other countries providing a net flow into Canada and the United States.Canada, United States, Migration, Brain Drain, Brain-drain, Braindrain, Graduates, Temporary Visa, Visas

    Inequalities in the dental health needs and access to dental services among looked after children in Scotland: a population data linkage study

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    Background: There is limited evidence on the health needs and service access among children and young people who are looked after by the state. The aim of this study was to compare dental treatment needs and access to dental services (as an exemplar of wider health and well-being concerns) among children and young people who are looked after with the general child population. Methods: Population data linkage study utilising national datasets of social work referrals for ‘looked after’ placements, the Scottish census of children in local authority schools, and national health service’s dental health and service datasets. Results: 633 204 children in publicly funded schools in Scotland during the academic year 2011/2012, of whom 10 927 (1.7%) were known to be looked after during that or a previous year (from 2007–2008). The children in the looked after children (LAC) group were more likely to have urgent dental treatment need at 5 years of age: 23%vs10% (n=209/16533), adjusted (for age, sex and area socioeconomic deprivation) OR 2.65 (95% CI 2.30 to 3.05); were less likely to attend a dentist regularly: 51%vs63% (n=5519/388934), 0.55 (0.53 to 0.58) and more likely to have teeth extracted under general anaesthesia: 9%vs5% (n=967/30253), 1.91 (1.78 to 2.04). Conclusions: LAC are more likely to have dental treatment needs and less likely to access dental services even when accounting for sociodemographic factors. Greater efforts are required to integrate child social and healthcare for LAC and to develop preventive care pathways on entering and throughout their time in the care system
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