580 research outputs found

    Gutzwiller Monte Carlo approach for a critical dissipative spin model

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    We use the Gutzwiller Monte Carlo approach to simulate the dissipative XYZ-model in the vicinity of a dissipative phase transition. This approach captures classical spatial correlations together with the full on-site quantum behavior, while neglecting non-local quantum effects. By considering finite two-dimensional lattices of various sizes, we identify a ferromagnetic and two paramagnetic phases, in agreement with earlier studies. The greatly reduced numerical complexity the Gutzwiller Monte Carlo approach facilitates efficient simulation of relatively large lattice sizes. The inclusion of the spatial correlations allows to describe critical behavior which is completely missed by the widely applied Gutzwiller decoupling of the density matrix

    Factors influencing clinical trial site selection in Europe: the Survey of Attitudes towards Trial sites in Europe (the SAT-EU Study).

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    This is the final version of the article. Available from the publisher via the DOI in this record.OBJECTIVES: Applications to run clinical trials in Europe fell 25% between 2007 and 2011. Costs, speed of approvals and shortcomings of European Clinical Trial Directive are commonly invoked to explain this unsatisfactory performance. However, no hard evidence is available on the actual weight of these factors or has it been previously investigated whether other criteria may also impact clinical trial site selection. DESIGN: The Survey of Attitudes towards Trial sites in Europe (SAT-EU Study) was an anonymous, cross-sectional web-based survey that systematically assessed factors impacting European clinical trial site selection. It explored 19 factors across investigator-driven, hospital-driven and environment-driven criteria, and costs. It also surveyed perceptions of the European trial environment. SETTING AND PARTICIPANTS: Clinical research organisations (CROs), academic clinical trial units (CTUs) and industry invited to respond. OUTCOME MEASURES: PRIMARY OUTCOME: weight assigned to each factor hypothesised to impact trial site selection and trial incidence. Secondary outcome: desirability of European countries to run clinical trials. RESULTS: Responses were obtained from 485 professionals in 34 countries: 49% from BioPharma, 40% from CTUs or CROs. Investigator-dependent, environment-dependent and hospital-dependent factors were rated highly important, costs being less important (p<0.0001). Within environment-driven criteria, pool of eligible patients, speed of approvals and presence of disease-management networks were significantly more important than costs or government financial incentives (p<0.0001). The pattern of response was consistent across respondent groupings (CTU vs CRO vs industry). Considerable variability was demonstrated in the perceived receptivity of countries to undertake clinical trials, with Germany, the UK and the Netherlands rated the best trial markets (p<0.0001). CONCLUSIONS: Investigator-dependent factors and ease of approval dominate trial site selection, while costs appear less important. Fostering competitiveness of European clinical research may not require additional government spending/incentives. Rather, harmonisation of approval processes, greater visibility of centres of excellence and reduction of 'hidden' indirect costs, may bring significantly more clinical trials to Europe

    Antimicrobial Peptide Evolution in the Asiatic Honey Bee Apis cerana

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    The Asiatic honeybee, Apis cerana Fabricius, is an important honeybee species in Asian countries. It is still found in the wild, but is also one of the few bee species that can be domesticated. It has acquired some genetic advantages and significantly different biological characteristics compared with other Apis species. However, it has been less studied, and over the past two decades, has become a threatened species in China. We designed primers for the sequences of the four antimicrobial peptide cDNA gene families (abaecin, defensin, apidaecin, and hymenoptaecin) of the Western honeybee, Apis mellifera L. and identified all the antimicrobial peptide cDNA genes in the Asiatic honeybee for the first time. All the sequences were amplified by reverse transcriptase-polymerase chain reaction (RT-PCR). In all, 29 different defensin cDNA genes coding 7 different defensin peptides, 11 different abaecin cDNA genes coding 2 different abaecin peptides, 13 different apidaecin cDNA genes coding 4 apidaecin peptides and 34 different hymenoptaecin cDNA genes coding 13 different hymenoptaecin peptides were cloned and identified from the Asiatic honeybee adult workers. Detailed comparison of these four antimicrobial peptide gene families with those of the Western honeybee revealed that there are many similarities in the quantity and amino acid components of peptides in the abaecin, defensin and apidaecin families, while many more hymenoptaecin peptides are found in the Asiatic honeybee than those in the Western honeybee (13 versus 1). The results indicated that the Asiatic honeybee adult generated more variable antimicrobial peptides, especially hymenoptaecin peptides than the Western honeybee when stimulated by pathogens or injury. This suggests that, compared to the Western honeybee that has a longer history of domestication, selection on the Asiatic honeybee has favored the generation of more variable antimicrobial peptides as protection against pathogens

    Cutaneous pathology in primary erythermalgia

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    Primary or idiopathic erythermalgia is characterized by recurrent, red, warm, and painful lower extremities. It arises at young age and persists throughout life because no treatment is available. We report the cutaneous pathology of affected skin lesions of three patients with primary erythermalgia. Biopsy specimens showed a mild perivascular mononuclear infiltrate, thickened blood vessel basement membranes, abundant perivascular edema, and moderate endothelial swelling. The thickened basal membrane of the blood vessels showed a laminar structure, and abundant perivascular edema and moderate endothelial cell swelling were evident. These histopathologic findings in primary erythermalgia appear to be nonspecific but allow diagnostic differentiation from erythromelalgia in which fibromuscular intimal proliferation and occlusive thrombi in the endarteriolar capillaries are apparent and from erythermalgia secondary to vasculitis. Histopathologic examination of affected skin lesions in patients with red, congested, warm, and painful burning extremities is a valuable tool in the diagnostic process

    Feynman path-integral treatment of the BEC-impurity polaron

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    The description of an impurity atom in a Bose-Einstein condensate can be cast in the form of Frohlich's polaron Hamiltonian, where the Bogoliubov excitations play the role of the phonons. An expression for the corresponding polaronic coupling strength is derived, relating the coupling strength to the scattering lengths, the trap size and the number of Bose condensed atoms. This allows to identify several approaches to reach the strong-coupling limit for the quantum gas polarons, whereas this limit was hitherto experimentally inaccessible in solids. We apply Feynman's path-integral method to calculate for all coupling strengths the polaronic shift in the free energy and the increase in the effective mass. The effect of temperature on these quantities is included in the description. We find similarities to the acoustic polaron results and indications of a transition between free polarons and self-trapped polarons. The prospects, based on the current theory, of investigating the polaron physics with ultracold gases are discussed for lithium atoms in a sodium condensate.Comment: 13 pages, 3 figure

    Galaxy And Mass Assembly (GAMA) : refining the local galaxy merger rate using morphological information

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    KRVS acknowledges the Science and Technology Facilities Council (STFC) for providing funding for this project, as well as the Government of Catalonia for a research travel grant (ref. 2010 BE-00268) to begin this project at the University of Nottingham. PN acknowledges the support of the Royal Society through the award of a University Research Fellowship and the European Research Council, through receipt of a Starting Grant (DEGAS-259586).We use the Galaxy And Mass Assembly (GAMA) survey to measure the local Universe mass-dependent merger fraction and merger rate using galaxy pairs and the CAS (concentration, asymmetry, and smoothness) structural method, which identifies highly asymmetric merger candidate galaxies. Our goals are to determine which types of mergers produce highly asymmetrical galaxies and to provide a new measurement of the local galaxy major merger rate. We examine galaxy pairs at stellar mass limits down to M* = 108 M⊙ with mass ratios of 4:1) the lower mass companion becomes highly asymmetric, whereas the larger galaxy is much less affected. The fraction of highly asymmetric paired galaxies which have a major merger companion is highest for the most massive galaxies and drops progressively with decreasing mass. We calculate that the mass-dependent major merger fraction is fairly constant at ∼1.3–2 per cent within 109.5 < M* < 1011.5 M⊙, and increases to ∼4 per cent at lower masses. When the observability time-scales are taken into consideration, the major merger rate is found to approximately triple over the mass range we consider. The total comoving volume major merger rate over the range 108.0 < M* < 1011.5 M⊙ is (1.2 ± 0.5) × 10−3 h370 Mpc−3 Gyr−1.Publisher PDFPeer reviewe

    Galaxy Zoo: Are Bars Responsible for the Feeding of Active Galactic Nuclei at 0.2 < z < 1.0?

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    We present a new study investigating whether active galactic nuclei (AGN) beyond the local universe are preferentially fed via large-scale bars. Our investigation combines data from Chandra and Galaxy Zoo: Hubble (GZH) in the AEGIS, COSMOS, and GOODS-S surveys to create samples of face-on, disc galaxies at 0.2 < z < 1.0. We use a novel method to robustly compare a sample of 120 AGN host galaxies, defined to have 10^42 erg/s < L_X < 10^44 erg/s, with inactive control galaxies matched in stellar mass, rest-frame colour, size, Sersic index, and redshift. Using the GZH bar classifications of each sample, we demonstrate that AGN hosts show no statistically significant enhancement in bar fraction or average bar likelihood compared to closely-matched inactive galaxies. In detail, we find that the AGN bar fraction cannot be enhanced above the control bar fraction by more than a factor of two, at 99.7% confidence. We similarly find no significant difference in the AGN fraction among barred and non-barred galaxies. Thus we find no compelling evidence that large-scale bars directly fuel AGN at 0.2<z<1.0. This result, coupled with previous results at z=0, implies that moderate-luminosity AGN have not been preferentially fed by large-scale bars since z=1. Furthermore, given the low bar fractions at z>1, our findings suggest that large-scale bars have likely never directly been a dominant fueling mechanism for supermassive black hole growth.Comment: 13 pages, 5 figures, 2 tables, accepted by MNRA

    A Description of Clinician Reported Diagnosis of Type 2 Diabetes and Other Non-Type 1 Diabetes Included in a Large International Multicentered Pediatric Diabetes Registry (SWEET)

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    Although type 1 diabetes (T1D) remains the most frequent form of diabetes in individuals aged less than 20 years at onset, other forms of diabetes are being increasingly recognized.info:eu-repo/semantics/publishedVersio
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