292 research outputs found

    Magnetic and thermal properties of 4f-3d ladder-type molecular compounds

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    We report on the low-temperature magnetic susceptibilities and specific heats of the isostructural spin-ladder molecular complexes L2_{2}[M(opba)]_{3\cdot xDMSOy\cdot yH2_{2}O, hereafter abbreviated with L2_{2}M3_{3} (where L = La, Gd, Tb, Dy, Ho and M = Cu, Zn). The results show that the Cu containing complexes (with the exception of La2_{2}Cu3_{3}) undergo long range magnetic order at temperatures below 2 K, and that for Gd2_{2}Cu3_{3} this ordering is ferromagnetic, whereas for Tb2_{2}Cu3_{3} and Dy2_{2}Cu3_{3} it is probably antiferromagnetic. The susceptibilities and specific heats of Tb2_{2}Cu3_{3} and Dy2_{2}Cu3_{3} above TCT_{C} have been explained by means of a model taking into account nearest as well as next-nearest neighbor magnetic interactions. We show that the intraladder L--Cu interaction is the predominant one and that it is ferromagnetic for L = Gd, Tb and Dy. For the cases of Tb, Dy and Ho containing complexes, strong crystal field effects on the magnetic and thermal properties have to be taken into account. The magnetic coupling between the (ferromagnetic) ladders is found to be very weak and is probably of dipolar origin.Comment: 13 pages, 15 figures, submitted to Phys. Rev.

    Numerical study on the flexural behaviour of slim-floor beams with hollow core slabs at elevated temperature

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    [EN] Slim-floor beams are a novel typology of steel beams where the steel profile is fully embedded within the concrete floor depth. While the use of this system is increasing fast in the construction practice, the available investigations on its fire performance are still scarce. This paper focuses on analysing the fire behaviour of slim floor beams combined with hollow core slabs as flooring system. Two configurations are studied, namely Integrated Floor Beam (IFB) and Shallow Floor Beam (SFB). A finite element model is developed and validated by comparison with experimental results available in the literature as well as with thermal tests carried out by the authors. Subsequently, parametric studies are conducted with the aim of providing practical design recommendations. The influence of the composite beam configuration, concrete type, longitudinal reinforcement and steel plate thickness is studied. The conclusions drawn in this paper suggest that the SFB configuration may provide a significant enhancement in terms of fire resistance compared to IFB, provided that the appropriate combination of the parameters studied is used.The authors would like to express their sincere gratitude to the Spanish "Ministerio de Economia y Competitividad" for the help provided through the Project BIA2015-67192-R and to the European Union through the FEDER funds.Albero Gabarda, V.; Espinós Capilla, A.; Serra Mercé, E.; Romero, ML.; Hospitaler Pérez, A. (2019). Numerical study on the flexural behaviour of slim-floor beams with hollow core slabs at elevated temperature. Engineering Structures. 180:561-573. https://doi.org/10.1016/j.engstruct.2018.11.061S56157318

    Vibrational properties of the one-component σ\sigma phase

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    A structural model of a one-component σ\sigma-phase crystal has been constructed by means of molecular dynamics simulation. The phonon dispersion curves and the vibrational density of states were computed for this model. The dependence of the vibrational properties on the thermodynamical parameters was investigated. The vibrational density of states of the σ\sigma-phase structure is found to be similar to that of a one-component glass with icosahedral local order. On the basis of this comparison it is concluded that the σ\sigma phase can be considered to be a good crystalline reference structure for this glass

    Improving Genetic Prediction by Leveraging Genetic Correlations Among Human Diseases and Traits

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    Genomic prediction has the potential to contribute to precision medicine. However, to date, the utility of such predictors is limited due to low accuracy for most traits. Here theory and simulation study are used to demonstrate that widespread pleiotropy among phenotypes can be utilised to improve genomic risk prediction. We show how a genetic predictor can be created as a weighted index that combines published genome-wide association study (GWAS) summary statistics across many different traits. We apply this framework to predict risk of schizophrenia and bipolar disorder in the Psychiatric Genomics consortium data, finding substantial heterogeneity in prediction accuracy increases across cohorts. For six additional phenotypes in the UK Biobank data, we find increases in prediction accuracy ranging from 0.7 for height to 47 for type 2 diabetes, when using a multi-trait predictor that combines published summary statistics from multiple traits, as compared to a predictor based only on one trait. © 2018 The Author(s)

    The comparative responsiveness of Hospital Universitario Princesa Index and other composite indices for assessing rheumatoid arthritis activity

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    Objective To evaluate the responsiveness in terms of correlation of the Hospital Universitario La Princesa Index (HUPI) comparatively to the traditional composite indices used to assess disease activity in rheumatoid arthritis (RA), and to compare the performance of HUPI-based response criteria with that of the EULAR response criteria. Methods Secondary data analysis from the following studies: ACT-RAY (clinical trial), PROAR (early RA cohort) and EMECAR (pre-biologic era long term RA cohort). Responsiveness was evaluated by: 1) comparing change from baseline (Delta) of HUPI with Delta in other scores by calculating correlation coefficients; 2) calculating standardised effect sizes. The accuracy of response by HUPI and by EULAR criteria was analyzed using linear regressions in which the dependent variable was change in global assessment by physician (Delta GDA-Phy). Results Delta HUPI correlation with change in all other indices ranged from 0.387 to 0.791); HUPI's standardized effect size was larger than those from the other indices in each database used. In ACT-RAY, depending on visit, between 65 and 80% of patients were equally classified by HUPI and EULAR response criteria. However, HUPI criteria were slightly more stringent, with higher percentage of patients classified as non-responder, especially at early visits. HUPI response criteria showed a slightly higher accuracy than EULAR response criteria when using Delta GDA-Phy as gold standard. Conclusion HUPI shows good responsiveness in terms of correlation in each studied scenario (clinical trial, early RA cohort, and established RA cohort). Response criteria by HUPI seem more stringent than EULAR''s

    Genome-wide association study identifies 30 Loci Associated with Bipolar Disorder

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    This paper is dedicated to the memory of Psychiatric Genomics Consortium (PGC) founding member and Bipolar disorder working group co-chair Pamela Sklar. We thank the participants who donated their time, experiences and DNA to this research, and to the clinical and scientific teams that worked with them. We are deeply indebted to the investigators who comprise the PGC. The views expressed are those of the authors and not necessarily those of any funding or regulatory body. Analyses were carried out on the NL Genetic Cluster Computer (http://www.geneticcluster.org ) hosted by SURFsara, and the Mount Sinai high performance computing cluster (http://hpc.mssm.edu).Bipolar disorder is a highly heritable psychiatric disorder. We performed a genome-wide association study including 20,352 cases and 31,358 controls of European descent, with follow-up analysis of 822 variants with P<1x10-4 in an additional 9,412 cases and 137,760 controls. Eight of the 19 variants that were genome-wide significant (GWS, p < 5x10-8) in the discovery GWAS were not GWS in the combined analysis, consistent with small effect sizes and limited power but also with genetic heterogeneity. In the combined analysis 30 loci were GWS including 20 novel loci. The significant loci contain genes encoding ion channels, neurotransmitter transporters and synaptic components. Pathway analysis revealed nine significantly enriched gene-sets including regulation of insulin secretion and endocannabinoid signaling. BDI is strongly genetically correlated with schizophrenia, driven by psychosis, whereas BDII is more strongly correlated with major depressive disorder. These findings address key clinical questions and provide potential new biological mechanisms for BD.This work was funded in part by the Brain and Behavior Research Foundation, Stanley Medical Research Institute, University of Michigan, Pritzker Neuropsychiatric Disorders Research Fund L.L.C., Marriot Foundation and the Mayo Clinic Center for Individualized Medicine, the NIMH Intramural Research Program; Canadian Institutes of Health Research; the UK Maudsley NHS Foundation Trust, NIHR, NRS, MRC, Wellcome Trust; European Research Council; German Ministry for Education and Research, German Research Foundation IZKF of Münster, Deutsche Forschungsgemeinschaft, ImmunoSensation, the Dr. Lisa-Oehler Foundation, University of Bonn; the Swiss National Science Foundation; French Foundation FondaMental and ANR; Spanish Ministerio de Economía, CIBERSAM, Industria y Competitividad, European Regional Development Fund (ERDF), Generalitat de Catalunya, EU Horizon 2020 Research and Innovation Programme; BBMRI-NL; South-East Norway Regional Health Authority and Mrs. Throne-Holst; Swedish Research Council, Stockholm County Council, Söderström Foundation; Lundbeck Foundation, Aarhus University; Australia NHMRC, NSW Ministry of Health, Janette M O'Neil and Betty C Lynch

    On the mechanisms governing gas penetration into a tokamak plasma during a massive gas injection

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    A new 1D radial fluid code, IMAGINE, is used to simulate the penetration of gas into a tokamak plasma during a massive gas injection (MGI). The main result is that the gas is in general strongly braked as it reaches the plasma, due to mechanisms related to charge exchange and (to a smaller extent) recombination. As a result, only a fraction of the gas penetrates into the plasma. Also, a shock wave is created in the gas which propagates away from the plasma, braking and compressing the incoming gas. Simulation results are quantitatively consistent, at least in terms of orders of magnitude, with experimental data for a D 2 MGI into a JET Ohmic plasma. Simulations of MGI into the background plasma surrounding a runaway electron beam show that if the background electron density is too high, the gas may not penetrate, suggesting a possible explanation for the recent results of Reux et al in JET (2015 Nucl. Fusion 55 093013)
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