Periodic homogenization and damage evolution in RVE composite material with inclusion

This work deals with the coupling between a periodic homogenization procedure and a damage process occurring in a RVE of inclusion composite materials. We mainly seek on the one hand to determine the effective mechanical properties according to the different volume fractions and forms of inclusions for a composite with inclusions at the macroscopic level, and on the other hand to explore the rupture mechanisms that can take place at the microstructure level. To do this; the first step is to propose a periodic homogenization procedure to predict the homogenized mechanical characteristics of an inclusion composite. This homogenization procedure is applied to the theory based on finite element analysis by the Abaqus calculation code. The inclusions are modeled by a random object modeler, and the periodic homogenization method is implemented by python scripts. It is then a matter of introducing the damage into the problem of homogenization, that is to say; once the homogenized characteristics are assessed in the absence of the damage initiated by microcracks and micro cavitations, it is then possible to introduce damage models by a subroutine (Umat) in the Abaqus calculation code. The verifications carried out focused on RVE of composite materials with inclusions

Research response to coronavirus disease 2019 needed better coordination and collaboration: a living mapping of registered trials

Objectives: Researchers worldwide are actively engaging in research activities to search for preventive and therapeutic interventions against coronavirus disease 2019 (COVID-19). Our aim was to describe the planning of randomized controlled trials (RCTs) in terms of timing related to the course of the COVID-19 epidemic and research question evaluated. Study Design and Setting: We performed a living mapping of RCTs registered in the WHO International Clinical Trials Registry Platform. We systematically search the platform every week for all RCTs evaluating preventive interventions and treatments for COVID-19 and created a publicly available interactive mapping tool at https://covid-nma.com to visualize all trials registered. Results: By August 12, 2020, 1,568 trials for COVID-19 were registered worldwide. Overall, the median ([Q1–Q3]; range) delay between the first case recorded in each country and the first RCT registered was 47 days ([33–67]; 15–163). For the 9 countries with the highest number of trials registered, most trials were registered after the peak of the epidemic (from 100% trials in Italy to 38% in the United States). Most trials evaluated treatments (1,333 trials; 85%); only 223 (14%) evaluated preventive strategies and 12 postacute period intervention. A total of 254 trials were planned to assess different regimens of hydroxychloroquine with an expected sample size of 110,883 patients. Conclusion: This living mapping analysis showed that COVID-19 trials have relatively small sample size with certain redundancy in research questions. Most trials were registered when the first peak of the pandemic has passed

Access Control to Materialized Views: an Inference-Based Approach

International audienceEnsuring security of data is one of the fundamental needs of people. In this context, issues related to confidentiality, integrity and availability of the data arise with a crucial importance, whether in economic, legal or medical domains. Standards covering fine-grained access control were proposed and adopted to control access to data through queries. In this paper, we propose a novel approach to facilitate the administration of access control rules to ensure the confidentiality of data at the level of materialized views. Several techniques and models have been proposed to control access to databases, but to our knowledge the problem of automatically generating from access control rules defined over base relations the applicable access control rules needed to control materialized views is not investigated. We are investigating this problem by resorting to an adaptation of query rewriting techniques. We choose to express fine-grained access control through authorization views. This paper mainly discusses the problem of automatically ensuring confidentiality of materialized views based on basic access control rules, and identifies formal tools to tackle the problem

Securing Materialized Views: a Rewriting-Based Approach

National audiencePlusieurs modèles et techniques ont été proposés pour contrôler l'accès aux bases de données. Nous nous intéressons dans ce papier au problème de générer automatiquement à partir des politiques de contrôle d'accès définies sur les relations de base, les politiques de contrôle d'accès qui seront attachées aux vues matérialisées. Nous avons choisi d'exprimer des règles de contrôle d'accès à grains fins à travers l'utilisation des vues d'autorisations. Nous nous basons dans notre approche sur l'adaptation des techniques de réécriture de requêtes aux spécificités de notre problème. Nous nous concentrons principalement sur les vues exprimées en requêtes conjonctives avec égalités. Nous montrons que notre approche est sécurisée (aucune divulgation d'information) et sous certaines conditions, l'approche est maximale (toutes les données autorisées sont accessibles)

Securing Materialized Views: a Rewriting-Based Approach

National audiencePlusieurs modèles et techniques ont été proposés pour contrôler l'accès aux bases de données. Nous nous intéressons dans ce papier au problème de générer automatiquement à partir des politiques de contrôle d'accès définies sur les relations de base, les politiques de contrôle d'accès qui seront attachées aux vues matérialisées. Nous avons choisi d'exprimer des règles de contrôle d'accès à grains fins à travers l'utilisation des vues d'autorisations. Nous nous basons dans notre approche sur l'adaptation des techniques de réécriture de requêtes aux spécificités de notre problème. Nous nous concentrons principalement sur les vues exprimées en requêtes conjonctives avec égalités. Nous montrons que notre approche est sécurisée (aucune divulgation d'information) et sous certaines conditions, l'approche est maximale (toutes les données autorisées sont accessibles)

Authorization Policies for Materialized Views

Part 13: Short PapersInternational audienceIn this paper, we propose a novel approach to facilitate the administration of access control policies to ensure the confidentiality of data at the level of materialized views. A materialized view stores both the definition of the view and the rows resulting from the execution of the view. Several techniques and models have been proposed to control access to databases, but to our knowledge the problem of automatically generating from access control policies defined over base relations the access control policies that are needed to control materialized views is not investigated so far. We are dealing with this problem by resorting to an adaptation of query rewriting techniques. We choose to express fine-grained access control through authorization views

Clinical characteristics and risk factors of extensive macular atrophy with pseudodrusen The EMAP case-control national clinical trial

Purpose: To assess the association of clinical and biological factors with extensive macular atrophy with pseudodrusen (EMAP) characterized by bilateral macular atrophy occurring in patients aged 50 to 60 years and a rapid progression to legal blindness within 5 to 10 years. Design: A national matched case-control study. Participants: Participants were recruited in 10 French Departments of Ophthalmology and their associated clinical investigation centers. All 115 patients with EMAP had symptoms before the age of 55 years due to bilateral extensive macular atrophy with a larger vertical axis and diffuse pseudodrusen. Three controls without age-related macular degeneration (AMD) or retinal disease at fundus examination were matched for each patient with EMAP by gender, age, and geographic area (in total 415). Methods: Subjects and controls underwent an eye examination including color, red-free autofluorescent fundus photographs and spectral-domain optical coherence tomography with macular analysis. The interviews collected demographic, lifestyle, family and personal medical history, medications, and biological data. Associations of risk factors were estimated using conditional logistic regression. Main Outcome Measures: Extensive macular atrophy with pseudodrusen status (cases vs. controls). Results: Extensive macular atrophy with pseudodrusen most frequently affected women (70 women, 45 men). After multivariate adjustment, family history of glaucoma or AMD was strongly associated with EMAP (odds ratio [OR], 2.3, P = 0.008 and OR, 1.5, P = 0.01, respectively). No association was found with cardiac diseases or their risk factors. Mild and moderate kidney disease and higher neutrophil rate were associated with a reduced risk of EMAP (OR, 0.58, P = 0.04; OR, 0.34, P = 0.01; and OR, 0.59, P = 0.003, respectively). On the contrary, eosinophilia (OR, 1.6; P = 0.0002), lymphocytosis (OR, 1.84; P = 0.0002), increased erythrocyte sedimentation rate (OR, 6.5; P = 0.0005), decreased CH50 (P = 0.001), and high plasma C3 level (P = 0.023) were significantly associated with a higher risk of EMAP. Conclusions: This study documents an association between EMAP and family history of AMD and glaucoma, a clear female predominance, and a systemic inflammatory profile. The reduced CH50 and increased C3 plasma values could reflect a more severe complement pathway dysfunction than in AMD, leading to early pseudodrusen and rapid development of geographic atrophy. There is no association of EMAP with AMD cardiac diseases or cardiac risks, including cigarette smoking

Reproducibility of fluorescent expression from engineered biological constructs in E. coli

We present results of the first large-scale interlaboratory study carried out in synthetic biology, as part of the 2014 and 2015 International Genetically Engineered Machine (iGEM) competitions. Participants at 88 institutions around the world measured fluorescence from three engineered constitutive constructs in E. coli. Few participants were able to measure absolute fluorescence, so data was analyzed in terms of ratios. Precision was strongly related to fluorescent strength, ranging from 1.54-fold standard deviation for the ratio between strong promoters to 5.75-fold for the ratio between the strongest and weakest promoter, and while host strain did not affect expression ratios, choice of instrument did. This result shows that high quantitative precision and reproducibility of results is possible, while at the same time indicating areas needing improved laboratory practices.Peer reviewe