129 research outputs found

    A strongly interacting Bose gas: Nozi\`eres and Schmitt-Rink theory and beyond

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    We calculate the critical temperature for Bose-Einstein condensation in a gas of bosonic atoms across a Feshbach resonance, and show how medium effects at negative scattering lengths give rise to pairs reminiscent of the ones responsible for fermionic superfluidity. We find that the formation of pairs leads to a large suppression of the critical temperature. Within the formalism developed by Nozieres and Schmitt-Rink the gas appears mechanically stable throughout the entire crossover region, but when interactions between pairs are taken into account we show that the gas becomes unstable close to the critical temperature. We discuss prospects of observing these effects in a gas of ultracold Cs133 atoms where recent measurements indicate that the gas may be sufficiently long-lived to explore the many-body physics around a Feshbach resonance.Comment: 8 pages, 8 figures, RevTeX. Significantly expanded to include effects beyond NS

    A user-friendly web portal for T-Coffee on supercomputers

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    <p>Abstract</p> <p>Background</p> <p>Parallel T-Coffee (PTC) was the first parallel implementation of the T-Coffee multiple sequence alignment tool. It is based on MPI and RMA mechanisms. Its purpose is to reduce the execution time of the large-scale sequence alignments. It can be run on distributed memory clusters allowing users to align data sets consisting of hundreds of proteins within a reasonable time. However, most of the potential users of this tool are not familiar with the use of grids or supercomputers.</p> <p>Results</p> <p>In this paper we show how PTC can be easily deployed and controlled on a super computer architecture using a web portal developed using Rapid. Rapid is a tool for efficiently generating standardized portlets for a wide range of applications and the approach described here is generic enough to be applied to other applications, or to deploy PTC on different HPC environments.</p> <p>Conclusions</p> <p>The PTC portal allows users to upload a large number of sequences to be aligned by the parallel version of TC that cannot be aligned by a single machine due to memory and execution time constraints. The web portal provides a user-friendly solution.</p

    Achieving the Neel state in an optical lattice

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    We theoretically study the possibility of reaching the antiferromagnetic phase of the Hubbard model by starting from a normal gas of trapped fermionic atoms and adiabatically ramping up an optical lattice. Requirements on the initial temperature and the number of atoms are determined for a three dimensional square lattice by evaluating the Neel state entropy, taking into account fluctuations around the mean-field solution. We find that these fluctuations place important limitations on adiabatically reaching the Neel state.Comment: 4 pages, 2 figures, RevTeX. Revised version incorporates minor corrections. Journal reference adde

    Scoping literature review and focus groups with healthcare professionals on psychosocial and lifestyle assessments for childhood obesity care

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    Background: Childhood obesity is a complex disease resulting from the interaction of multiple factors. The effective management of childhood obesity requires assessing the psychosocial and lifestyle factors that may play a role in the development and maintenance of obesity. This study centers on available scientific literature on psychosocial and lifestyle assessments for childhood obesity, and experiences and views of healthcare professionals with regard to assessing psychosocial and lifestyle factors within Dutch integrated care. Methods: Two methods were used. First, a scoping review (in PubMed, Embase, PsycInfo, IBSS, Scopus and Web of Science) was performed by systematically searching for scientific literature on psychosocial and lifestyle assessments for childhood obesity. Data were analysed by extracting data in Microsoft Excel. Second, focus group discussions were held with healthcare professionals from a variety of disciplines and domains to explore their experiences and views about assessing psychosocial and lifestyle factors within Dutch integrated care. Data were analysed using template analysis, complemented with open coding in MAXQDA. Results: The results provide an overview of relevant psychosocial and lifestyle factors that should be assessed and were classified as child, family, parental and lifestyle (e.g. nutrition, physical activity and sleep factors) and structured into psychological and social aspects. Insights into how to assess psychosocial and lifestyle factors were identified as well, including talking about psychosocial factors, lifestyle and weight; the professional-patient relationship; and attitudes of healthcare professionals. Conclusions: This study provides an overview of psychosocial and lifestyle factors that should be identified within the context of childhood obesity care, as they may contribute to the development and maintenance of obesity. The results highlight the importance of both what is assessed and how it is assessed. The results of this study can be used to develop practical tools for facilitating healthcare professionals in conducting a psychosocial and lifestyle assessment.</p

    Characterization of Two VAO-Type Flavoprotein Oxidases from Myceliophthora thermophila

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    The VAO flavoprotein family consists mostly of oxidoreductases harboring a covalently linked flavin cofactor. The linkage can be either monocovalent at position 8 with a histidine or tyrosine or bicovalent at position 8 with a histidine and at position 6 with a cysteine. Bicovalently bound flavoproteins show a preference for bulkier substrates such as oligosaccharides or secondary metabolites. The genome of the thermophilic fungus Myceliophthora thermophila C1 was found to be rich in genes encoding putative covalent VAO-type flavoproteins. Enzymes from this fungus have the advantage of being rather thermostable and homologous overexpression in M. thermophila C1 is feasible. Recently we discovered a new and VAO-type carbohydrate oxidase from this fungus: xylooligosaccharide oxidase. In this study, two other putative VAO-type oxidases, protein sequence XP_003663615 (MtVAO615) and XP_003665713 (MtVAO713), were expressed in M. thermophila C1, purified and characterized. Enzyme MtVAO615 was found to contain a bicovalently bound FAD, while enzyme MtVAO713 contained a monocovalent histidyl-bound FAD. The crystal structures of both proteins were obtained which revealed atypical active site architectures. It could be experimentally verified that both proteins, when reduced, rapidly react with molecular oxygen, a hallmark of flavoprotein oxidases. A large panel of alcohols, including carbohydrates, steroids and secondary alcohols were tested as potential substrates. For enzyme MtVAO713 low oxidase activity was discovered towards ricinoleic acid

    Challenging the 'New Professionalism': from managerialism to pedagogy?

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    In recent years there have been changes made to the conceptualisation of continuing professional development for teachers in both the Scottish and English systems of education. These changes have been instigated by successive UK governments (and more recently, by the Scottish Executive), together with the General teaching Council for Scotland (GTCS) and the General Teaching Council for England (GTCE). This paper argues that these changes have not provided a clear rationale for CPD, but instead have introduced tensions between the concept of teacher education and that of training. The need for a less confused understanding of CPD and its purposes is underlined, as is the need for school based approaches to continuing teacher education. Arguably, teacher education must move from technicist emphases to a model which integrates the social processes of change within society and schools with the individual development and empowerment of teachers

    Translational implications of Th17-skewed inflammation due to genetic deficiency of a cadherin stress sensor

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    Desmoglein 1 (Dsg1) is a cadherin restricted to stratified tissues of terrestrial vertebrates, which serve as essential physical and immune barriers. Dsg1 loss-of-function mutations in humans result in skin lesions and multiple allergies, and isolated patient keratinocytes exhibit increased proallergic cytokine expression. However, the mechanism by which genetic deficiency of Dsg1 causes chronic inflammation is unknown. To determine the systemic response to Dsg1 loss, we deleted the 3 tandem Dsg1 genes in mice. Whole transcriptome analysis of embryonic Dsg1–/– skin showed a delay in expression of adhesion/differentiation/ keratinization genes at E17.5, a subset of which recovered or increased by E18.5. Comparing epidermal transcriptomes from Dsg1-deficient mice and humans revealed a shared IL-17–skewed inflammatory signature. Although the impaired intercellular adhesion observed in Dsg1–/– mice resembles that resulting from anti-Dsg1 pemphigus foliaceus antibodies, pemphigus skin lesions exhibit a weaker IL-17 signature. Consistent with the clinical importance of these findings, treatment of 2 Dsg1-deficient patients with an IL-12/IL-23 antagonist originally developed for psoriasis resulted in improvement of skin lesions. Thus, beyond impairing the physical barrier, loss of Dsg1 function through gene mutation results in a psoriatic-like inflammatory signature before birth, and treatment with a targeted therapy significantly improved skin lesions in patients

    Ten Misconceptions from the History of Analysis and Their Debunking

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    The widespread idea that infinitesimals were "eliminated" by the "great triumvirate" of Cantor, Dedekind, and Weierstrass is refuted by an uninterrupted chain of work on infinitesimal-enriched number systems. The elimination claim is an oversimplification created by triumvirate followers, who tend to view the history of analysis as a pre-ordained march toward the radiant future of Weierstrassian epsilontics. In the present text, we document distortions of the history of analysis stemming from the triumvirate ideology of ontological minimalism, which identified the continuum with a single number system. Such anachronistic distortions characterize the received interpretation of Stevin, Leibniz, d'Alembert, Cauchy, and others.Comment: 46 pages, 4 figures; Foundations of Science (2012). arXiv admin note: text overlap with arXiv:1108.2885 and arXiv:1110.545

    Ultracold atomic gases in optical lattices: mimicking condensed matter physics and beyond

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    We review recent developments in the physics of ultracold atomic and molecular gases in optical lattices. Such systems are nearly perfect realisations of various kinds of Hubbard models, and as such may very well serve to mimic condensed matter phenomena. We show how these systems may be employed as quantum simulators to answer some challenging open questions of condensed matter, and even high energy physics. After a short presentation of the models and the methods of treatment of such systems, we discuss in detail, which challenges of condensed matter physics can be addressed with (i) disordered ultracold lattice gases, (ii) frustrated ultracold gases, (iii) spinor lattice gases, (iv) lattice gases in "artificial" magnetic fields, and, last but not least, (v) quantum information processing in lattice gases. For completeness, also some recent progress related to the above topics with trapped cold gases will be discussed.Comment: Review article. v2: published version, 135 pages, 34 figure

    Impact analysis of accidents on the traffic flow based on massive floating car data

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    The wide usage of GPS-equipped devices enables the mass recording of vehicle movement trajectories describing the movement behavior of the traffic participants. An important aspect of the road traffic is the impact of anomalies, like accidents, on traffic flow. Accidents are especially important as they contribute to the the aspects of safety and also influence travel time estimations. In this paper, the impact of accidents is determined based on a massive GPS trajectory and accident dataset. Due to the missing precise date of the accidents in the data set used, first, the date of the accident is estimated based on the speed profile at the accident time. Further, the temporal impact of the accident is estimated using the speed profile of the whole day. The approach is applied in an experiment on a one month subset of the datasets. The results show that more than 72% of the accident dates are identified and the impact on the temporal dimension is approximated. Moreover, it can be seen that accidents during the rush hours and on high frequency road types (e.g. motorways, trunks or primaries) have an increasing effect on the impact duration on the traffic flow
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