53 research outputs found

    Correlation inequalities for classical and quantum XY models

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    We review correlation inequalities of truncated functions for the classical and quantum XY models. A consequence is that the critical temperature of the XY model is necessarily smaller than that of the Ising model, in both the classical and quantum cases. We also discuss an explicit lower bound on the critical temperature of the quantum XY model.Comment: 13 pages. Submitted to the volume "Advances in Quantum Mechanics: contemporary trends and open problems" of the INdAM-Springer series, proceedings of the INdAM meeting "Contemporary Trends in the Mathematics of Quantum Mechanics" (4-8 July 2016) organised by G. Dell'Antonio and A. Michelangel

    Normative brain volumetry derived from different reference populations: Impact on single-subject diagnostic assessment in dementia

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    Brain imaging data are increasingly made publicly accessible and volumetric imaging measures derived from population-based cohorts may serve as normative data for individual patient diagnostic assessment. Yet, these normative cohorts are usually not a perfect reflection of a patient’s base population, nor are imaging parameters such as field strength or scanner type similar. In this proof of principle study, we assessed differences between reference curves of subcortical structure volumes of normal controls derived from two population-based studies and a case-control study. We assessed the impact of any differences on individual assessment of brain structure volumes. Percentile curves were fitted on the three healthy cohorts. Next, percentile values for these subcortical structures for individual patients from these three cohorts, 91 mild cognitive impairment (MCI) and 95 Alzheimer’s Disease (AD) cases and patients from the Alzheimer Center (AC) were calculated, based on the distributions of each of the three cohorts. Overall we found that the subcortical volume normative data from these cohorts is highly interchangeable, suggesting more flexibility in clinical implementation

    Blood coagulation and beyond:Position paper from the Fourth Maastricht Consensus Conference on Thrombosis

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    The 4th Maastricht Consensus Conference on Thrombosis (MCCT), included the following themes: Theme 1: The coagulome as a critical driver of cardiovascular disease Blood coagulation proteins also play divergent roles in biology and pathophysiology, related to specific organs, including brain, heart, bone marrow and kidney. Four investigators shared their views on these organ-specific topics. Theme 2: Novel mechanisms of thrombosis Mechanisms linking factor XII to fibrin, including their structural and physical properties, contribute to thrombosis, which is also affected by variation in microbiome status. Virus infections associated-coagulopathies perturb the hemostatic balance resulting in thrombosis and/or bleeding. Theme 3: How to limit bleeding risks: insights from translational studies This theme included state of the art methodology for exploring the contribution of genetic determinants of a bleeding diathesis; determination of polymorphisms in genes that control the rate of metabolism by the liver of P2Y12 inhibitors, to improve safety of antithrombotic therapy. Novel reversal agents for direct oral anticoagulants are discussed. Theme 4: Hemostasis in extracorporeal systems: how to utilize ex vivo models? Perfusion flow chamber and nanotechnology developments are developed for studying bleeding and thrombosis tendencies. Vascularised organoids are utilized for disease modeling and drug development studies. Strategies for tackling extracorporeal membrane oxygenation (ECMO) associated coagulopathy are discussed. Theme 5: Clinical dilemmas in thrombosis and antithrombotic management Plenary presentations addressed controversial areas, ie thrombophilia testing, thrombosis risk assessment in hemophilia, novel antiplatelet strategies and clinically tested factor XI(a) inhibitors,both possibly with reduced bleeding risk. Finally, Covid-19 associated coagulopathy is revisited.</p

    Experimental confirmation of efficient island divertor operation and successful neoclassical transport optimization in Wendelstein 7-X

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    We present recent highlights from the most recent operation phases of Wendelstein 7-X, the most advanced stellarator in the world. Stable detachment with good particle exhaust, low impurity content, and energy confinement times exceeding 100 ms, have been maintained for tens of seconds. Pellet fueling allows for plasma phases with reduced ion-temperature-gradient turbulence, and during such phases, the overall confinement is so good (energy confinement times often exceeding 200 ms) that the attained density and temperature profiles would not have been possible in less optimized devices, since they would have had neoclassical transport losses exceeding the heating applied in W7-X. This provides proof that the reduction of neoclassical transport through magnetic field optimization is successful. W7-X plasmas generally show good impurity screening and high plasma purity, but there is evidence of longer impurity confinement times during turbulence-suppressed phases.EC/H2020/633053/EU/Implementation of activities described in the Roadmap to Fusion during Horizon 2020 through a Joint programme of the members of the EUROfusion consortium/ EUROfusio

    The Physics of the B Factories

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    Anion-induced contraction of helical receptors

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    Uptake of a tetrafluoroborate anion into the centre of a dicopper bis-salicylaldoxime complex causes a major contraction of the cavity and an increase in helicity
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