132 research outputs found

    What Are Polymorphically-Typed Ambients?

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    Abstract: The Ambient Calculus was developed by Cardelli and Gordon as a formal framework to study issues of mobility and migrant code. We consider an Ambient Calculus where ambients transport and exchange programs rather that just inert data. We propose different senses in which such a calculus can be said to be polymorphically typed, and design accordingly a polymorphic type system for it. Our type system assigns types to embedded programs and what we call behaviors to processes; a denotational semantics of behaviors is then proposed, here called trace semantics, underlying much of the remaining analysis. We state and prove a Subject Reduction property for our polymorphically typed calculus. Based on techniques borrowed from finite automata theory, type-checking of fully type-annotated processes is shown to be decidable; the time complexity of our decision procedure is exponential (this is a worst-case in theory, arguably not encountered in practice). Our polymorphically-typed calculus is a conservative extension of the typed Ambient Calculus originally proposed by Cardelli and Gordon

    Computationally Guided Design of a Readily Assembled Phosphite- Thioether Ligand for a Broad Range of Pd-Catalyzed Asymmetric Allylic Substitutions

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    A modular approach employing indene as common starting material, has enabled the straightforward preparation in three reaction steps of P-thioether ligands for the Pd-catalyzed asymmetric allylic substitution. The analysis of a starting library of P-thioether ligands based on rational design and theoretical calculations has led to the discovery of an optimized anthracenethiol derivative with excellent behavior in the reaction of choice. Improving most approaches reported to date, this ligand presents a broad substrate and nucleophile scope. Excellent enantioselectivities have been achieved for a range of linear and cyclic allylic substrates using a large number of C-, N-, and O-nucleophiles (40 compounds in total). The species responsible for the catalytic activity have been further investigated by NMR in order to clearly establish the origin of the enantioselectivity. The resulting products have been derivatized by means of ring-closing metathesis or Pauson–Khand reactions to further prove the synthetic versatility of the methodology for preparing enantiopure complex structures

    A cross-sectional study of the public health response to non-alcoholic fatty liver disease in Europe

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    Background & Aims: Non-alcoholic fatty liver disease (NAFLD) is a growing public health problem worldwide and has become an important field of biomedical inquiry. We aimed to determine whether European countries have mounted an adequate public health response to NAFLD and non-alcoholic steatohepatitis (NASH). Methods: In 2018 and 2019, NAFLD experts in 29 European countries completed an English-language survey on policies, guidelines, awareness, monitoring, diagnosis and clinical assessment in their country. The data were compiled, quality checked against existing official documents and reported descriptively. Results: None of the 29 participating countries had written strategies or action plans for NAFLD. Two countries (7%) had mentions of NAFLD or NASH in related existing strategies (obesity and alcohol). Ten (34%) reported having national clinical guidelines specifically addressing NAFLD and, upon diagnosis, all included recommendations for the assessment of diabetes and liver cirrhosis. Eleven countries (38%) recommended screening for NAFLD in all patients with either diabetes, obesity and/or metabolic syndrome. Five countries (17%) had referral algorithms for follow-up and specialist referral in primary care, and 7 (24%) reported structured lifestyle programmes aimed at NAFLD. Seven (24%) had funded awareness campaigns that specifically included prevention of liver disease. Four countries (14%) reported having civil society groups which address NAFLD and 3 countries (10%) had national registries that include NAFLD. Conclusions: We found that a comprehensive public health response to NAFLD is lacking in the surveyed European countries. This includes policy in the form of a strategy, clinical guidelines, awareness campaigns, civil society involvement, and health systems organisation, including registries. Lay summary: We conducted a survey on non-alcoholic fatty liver disease with experts in European countries, coupled with data extracted from official documents on policies, clinical guidelines, awareness, and monitoring. We found a general lack of national policies, awareness campaigns and civil society involvement, and few epidemiological registries

    POSITION PAPER OF THE CATALAN SOCIETY OF GASTROENTEROLOGY ABOUT HEPATIC ELASTOGRAPHY 2022

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    After almost 20 years using transient elastography (TE) for the non-invasive diagnosis of liver fibrosis, its use has been extended to population screening, evaluation of steatosis and complications of cirrhosis. For this reason, the "Catalan Society of Digestology" commissioned a group of experts to update the first Document carried out in 2011.The working group (8 doctors and 4 nurses) prepared a panel of questions based on the online survey "Hepatic Elastography in Catalonia 2022" following the PICO structure and the Delphi method.The answers are presented with the level of evidence, the degree of recommendation and the final consensus after being evaluated by 2 external reviewers.TE uses the simplest and most reliable elastographic method to quantify liver fibrosis, assess steatosis, and determine the risk of complications in patients with cirrhosis.Copyright © 2022 Elsevier España, S.L.U. All rights reserved

    Main Results of Phase IV BEMUSE Project: Simulation of LBLOCA in an NPP

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    Phase IV of BEMUSE Program is a necessary step for a subsequent uncertainty analysis. It includes the simulation of the reference scenario and a sensitivity study. The scenario is a LBLOCA and the reference plant is Zion 1 NPP, a 4 loop PWR unit. Thirteen participants coming from ten different countries have taken part in the exercise. The BEMUSE (Best Estimate Methods plus Uncertainty and Sensitivity Evaluation) Programhas been promoted by theWorking Group on AccidentManagement and Analysis (WGAMA) and endorsed by the Committee on the Safety of Nuclear Installations (CSNI). The paper presents the results of the calculations performed by participants and emphasizes its usefulness for future uncertainty evaluation, to be performed in next phase. The objectives of the activity are basically to simulate the LBLOCA reproducing the phenomena associated to the scenario and also to build a common, well-known, basis for the future comparison of uncertainty evaluation results among different methodologies and codes. The sensitivity calculations performed by participants are also presented. They allow studying the influence of different parameters such as material properties or initial and boundary conditions, upon the behaviour of the most relevant parameters related to the scenario

    Network meta‐analysis of post‐exposure prophylaxis randomized clinical trials

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    Objectives: We performed a network meta‐analysis of PEP randomized clinical trials to evaluate the best regimen. / Methods: After MEDLINE/Pubmed search, studies were included if: (1) were randomized, (2) comparing at least 2 PEP three‐drug regimens and, (3) reported completion rates or discontinuation at 28 days. Five studies with 1105 PEP initiations were included and compared ritonavir‐boosted lopinavir (LPV/r) vs. atazanavir (ATV) (one study), cobicistat‐boosted elvitegravir (EVG/c) (one study), raltegravir (RAL) (one study) or maraviroc (MVC) (two studies). We estimated the probability of each treatment of being the best based on the evaluation of five outcomes: PEP non‐completion at day 28, PEP discontinuation due to adverse events, PEP switching due to any cause, lost to follow‐up and adverse events. / Results: Participants were mostly men who have sex with men (n = 832, 75%) with non‐occupational exposure to HIV (89.86%). Four‐hundred fifty‐four (41%) participants failed to complete their PEP course for any reason. The Odds Ratio (OR) for PEP non‐completion at day 28 in each antiretroviral compared to LPV/r was: ATV 0.95 (95% CI 0.58–1.56; EVG/c: OR 0.65 95% CI 0.30–1.37; RAL: OR 0.68 95% CI 0.41–1.13; and MVC: OR 0.69 95% CI 0.47–1.01. In addition, the rankogram showed that EVG/c had the highest probability of being the best treatment for the lowest rates in PEP non‐completion at day 28, switching, lost to follow‐up or adverse events and MVC for PEP discontinuations due to adverse events. / Conclusions: Our study shows the advantages of integrase inhibitors when used as PEP, particularly EVG as a Single‐Tablet Regimen

    Trends in Data Locality Abstractions for HPC Systems

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    The cost of data movement has always been an important concern in high performance computing (HPC) systems. It has now become the dominant factor in terms of both energy consumption and performance. Support for expression of data locality has been explored in the past, but those efforts have had only modest success in being adopted in HPC applications for various reasons. them However, with the increasing complexity of the memory hierarchy and higher parallelism in emerging HPC systems, locality management has acquired a new urgency. Developers can no longer limit themselves to low-level solutions and ignore the potential for productivity and performance portability obtained by using locality abstractions. Fortunately, the trend emerging in recent literature on the topic alleviates many of the concerns that got in the way of their adoption by application developers. Data locality abstractions are available in the forms of libraries, data structures, languages and runtime systems; a common theme is increasing productivity without sacrificing performance. This paper examines these trends and identifies commonalities that can combine various locality concepts to develop a comprehensive approach to expressing and managing data locality on future large-scale high-performance computing systems

    SARS-CoV-2 Catalonia contact tracing program : evaluation of key performance indicators

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    Background: Guidance on SARS-CoV-2 contact tracing indicators have been recently revised by international public health agencies. The aim of the study is to describe and analyse contact tracing indicators based on Catalonia's (Spain) real data and proposing to update them according to recommendations. Methods: Retrospective cohort analysis including Catalonia's contact tracing dataset from 20 May until 31 December 2020. Descriptive statistics are performed including sociodemographic stratification by age, and differences are assessed over the study period. Results: We analysed 923,072 contacts from 301,522 SARS-CoV-2 cases with identified contacts (67.1% contact tracing coverage). The average number of contacts per case was 4.6 (median 3, range 1-243). A total of 403,377 contacts accepted follow-up through three phone calls over a 14-day quarantine period (84.5% of contacts requiring follow-up). The percentage of new cases declared as contacts 14 days prior to diagnosis evolved from 33.9% in May to 57.9% in November. All indicators significantly improved towards the target over time (p < 0.05 for all four indicators). Conclusions: Catalonia's SARS-CoV-2 contact tracing indicators improved over time despite challenging context. The critical revision of the indicator's framework aims to provide essential information in control policies, new indicators proposed will improve system delay's follow-up. The study provides information on COVID-19 indicators framework experience from country's real data, allowing to improve monitoring tools in 2021-2022. With the SARS-CoV-2 pandemic being so harmful to health systems and globally, is important to analyse and share contact tracing data with the scientific community
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