1,912 research outputs found

    A Bayesian defect-based physics-guided neural network model for probabilistic fatigue endurance limit evaluation

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    Accurate fatigue assessment of material plagued by defects is of utmost importance to guarantee safety and service continuity in engineering components. This study shows how state-of-the-art semi-empirical models can be endowed with additional defect descriptors to probabilistically predict the occurrence of fatigue failures by exploiting advanced Bayesian Physics-guided Neural Network (B-PGNN) approaches. A B-PGNN is thereby developed to predict the fatigue failure probability of a sample containing defects, referred to a given fatigue endurance limit. In this framework, a robustly calibrated El Haddad's curve is exploited as the prior physics reinforcement of the probabilistic model, i.e., prior knowledge. Following, a likelihood function is built and the B-PGNN is trained via Bayesian Inference, thus calculating the posterior of the parameters. The arbitrariness of the choice of the related architecture is circumvented through a Bayesian model selection strategy. A case-study is analysed to prove the robustness of the proposed approach. This methodology proposes an advanced practical approach to help support the probabilistic design against fatigue failure

    The Time of Flight System of the AMS-02 Space Experiment

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    The Time-of-Flight (TOF) system of the AMS detector gives the fast trigger to the read out electronics and measures velocity, direction and charge of the crossing particles. The new version of the detector (called AMS-02) will be installed on the International Space Station on March 2004. The fringing field of the AMS-02 superconducting magnet is 1.0÷2.51.0\div2.5 kG where the photomultiplers (PM) are installed. In order to be able to operate with this residual field, a new type of PM was chosen and the mechanical design was constrained by requiring to minimize the angle between the magnetic field vector and the PM axis. Due to strong field and to the curved light guides, the time resolution will be 150÷180150\div180 ps, while the new electronics will allow for a better charge measurement.Comment: 5 pages, 4 figures. Proc. of 7th Int. Conf. on Adv. Tech. and Part. Phys., 15-19 October 2001,Como (Italy

    La colección de Moseh ben Maimón en la Biblioteca Universitaria de Illinois, Urbana. Ediciones de los siglos XVI y XVII

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    The present work protends to study the presence in the library of the University of Illinois (Urbana, Illinois) of an important collection of ten theological and legal works by Moses ben Maimon, Maimonides. It provides a complete bibliographic information, including the references in catalogues and the localization of the extant copies of this rare bibliographic material in Latin and Hebrew, published posthu­mously.En este trabajo se informa de la presencia de una importante colección de diez obras teológicas y legales de Moisés ben Maimón, Maimónides, en la Biblioteca de la Universidad de Illinois (Urbana, Illinois). Se proporcionan las fichas bibliográficas completas incluyendo las referencias en catálogos y la localización de los ejemplares existentes de este raro material bibliográfico en latín y hebreo, que vio la luz póstumamente

    Recent advances in the pathogenesis and treatment of chronic lymphocytic leukemia.

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    AbstractChronic lymphocytic leukaemia (CLL) is a common lymphoid malignancy characterized by the expansion and progressive accumulation of mature autoreactive B lymphocytes. The disease is clinically heterogeneous and incurable by standard chemotherapy. A major feature of the disease is the marked dependence of the leukaemic cells on various microenvironmental stimuli, which promote leukaemia cell growth, survival, and drug-resistance. Recently, considerable progress has been made in the understanding of the molecular mechanisms that drive CLL. The identification of recurrent genetic lesions using next generation sequencing technology has provided new data on the pathophysiology of the disease and has improved its prognostication. The recognition of the critical role of the B cell receptor (BCR) in driving the disease has resulted in the development of BCR pathway inhibitors that have the potential to completely transform CLL treatment in the near future. Other novel therapeutic agents, such as BCL2 antagonists and chimeric antigen receptor (CAR)-modified T-cells, are also showing great promise in clinical trials. In this review, we summarize some of these recent advances, with a particular focus on the BCR and corresponding pathway inhibitors

    Structure-Dependent Influence of Moisture on Resistive Switching Behavior of ZnO Thin Films

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    Resistive switching mechanisms underlying memristive devices are widely investigated, and the importance as well as influence of ambient conditions on the electrical performances of memristive cells are already recognized. However, detailed understanding of the ambient effect on the switching mechanism still remains a challenge. This work presents an experimental investigation on the effect of moisture on resistive switching performances of ZnO-based electrochemical metallization memory cells. ZnO thin films are grown by chemical vapor deposition (CVD) and radio frequency sputtering. Water molecules are observed to influence electrical resistance of ZnO by affecting the electronic conduction mechanism and by providing additional species for ionic conduction. By influencing dissolution and migration of ionic species underlying resistive switching events, moisture is reported to tune resistive switching parameters. In particular, the presence of H2O is responsible for a decrease of the forming and SET voltages and an increase of the ON/OFF resistance ratio in both CVD and sputtered films. The effect of moisture on resistive switching performance is found to be more pronounced in case of sputtered films where the reduced grain size is responsible for an increased adsorption of water molecules and an increased amount of possible pathways for ion migration

    Epidemiology of intensive care unit-acquired sepsis in Italy: results of the SPIN-UTI network

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    BACKGROUND: Sepsis is the major cause of mortality from any infectious disease worldwide. Sepsis may be the result of a healthcare associated infection (HAI): the most frequent adverse events during care delivery especially in Intensive Care Units (ICUs). The main aim of the present study was to describe the epidemiology of ICU-acquired sepsis and related outcomes among patients enrolled in the framework of the Italian Nosocomial Infections Surveillance in ICUs - SPIN-UTI project. STUDY DESIGN: Prospective multicenter study. METHODS: The SPIN-UTI network adopted the European protocols for patient-based HAI surveillance. RESULTS: During the five editions of the SPIN-UTI project, from 2008 to 2017, 47.0% of HAIs has led to sepsis in 832 patients. Overall, 57.0% episodes were classified as sepsis, 20.5% as severe sepsis and 22.5% as septic shock. The most common isolated microorganisms from sepsis episodes were Acinetobacter baumannii, Klebsiella pneumoniae and Pseudomonas aeruginosa. The case fatality rate increased with the severity of sepsis and the mean length of ICU-stay was significantly higher in patients with ICU-acquired sepsis than in patients without. CONCLUSION: Our study provides evidence that ICU-acquired sepsis occurs frequently in Italian ICU patients and is associated with a high case fatality rate and increased length of stay. However, in order to explain these findings further analyses are needed in this population of ICU patient
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