Study of Concentrated Short Fiber Suspensions in Flows, Using Topological Data Analysis

The present study addresses the discrete simulation of the flow of concentrated suspensions encountered in the forming processes involving reinforced polymers, and more particularly the statistical characterization and description of the effects of the intense fiber interaction, occurring during the development of the flow induced orientation, on the fibers’ geometrical center trajectory. The number of interactions as well as the interaction intensity will depend on the fiber volume fraction and the applied shear, which should affect the stochastic trajectory. Topological data analysis (TDA) will be applied on the geometrical center trajectories of the simulated fiber to prove that a characteristic pattern can be extracted depending on the flow conditions (concentration and shear rate). This work proves that TDA allows capturing and extracting from the so-called persistence image, a pattern that characterizes the dependence of the fiber trajectory on the flow kinematics and the suspension concentration. Such a pattern could be used for classification and modeling purposes, in rheology or during processing monitoring

Describing and Modeling Rough Composites Surfaces by Using Topological Data Analysis and Fractional Brownian Motion

Many composite manufacturing processes employ the consolidation of pre-impregnated preforms. However, in order to obtain adequate performance of the formed part, intimate contact and molecular diffusion across the different composites’ preform layers must be ensured. The latter takes place as soon as the intimate contact occurs and the temperature remains high enough during the molecular reptation characteristic time. The former, in turn, depends on the applied compression force, the temperature and the composite rheology, which, during the processing, induce the flow of asperities, promoting the intimate contact. Thus, the initial roughness and its evolution during the process, become critical factors in the composite consolidation. Processing optimization and control are needed for an adequate model, enabling it to infer the consolidation degree from the material and process features. The parameters associated with the process are easily identifiable and measurable (e.g., temperature, compression force, process time, ⋯). The ones concerning the materials are also accessible; however, describing the surface roughness remains an issue. Usual statistical descriptors are too poor and, moreover, they are too far from the involved physics. The present paper focuses on the use of advanced descriptors out-performing usual statistical descriptors, in particular those based on the use of homology persistence (at the heart of the so-called topological data analysis—TDA), and their connection with fractional Brownian surfaces. The latter constitutes a performance surface generator able to represent the surface evolution all along the consolidation process, as the present paper emphasizes

Learning data-driven reduced elastic and inelastic models of spot-welded patches

Solving mechanical problems in large structures with rich localized behaviors remains a challenging issue despite the enormous advances in numerical procedures and computational performance. In particular, these localized behaviors need for extremely fine descriptions, and this has an associated impact in the number of degrees of freedom from one side, and the decrease of the time step employed in usual explicit time integrations, whose stability scales with the size of the smallest element involved in the mesh. In the present work we propose a data-driven technique for learning the rich behavior of a local patch and integrate it into a standard coarser description at the structure level. Thus, localized behaviors impact the global structural response without needing an explicit description of that fine scale behaviors

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

Local feature selection for urban image retrieval

International audienceIn this paper, we propose an improved image retrieval method, dedicated to images of buildings/landmarks from urban environments. Locally detected key points are binary labelled as building or no-building using a SVM-based classifier. Thereafter, only key points labelled as building are retained. In this way, the data in the database vocabulary is reduced to only the relevant one and solely the relevant features, effectively describing the targeted buildings are considered. The experimental results, carried out on the Paris6k and Oxford5k data sets show significant improvement in terms of retrieval precisio

Building recognition with adaptive interest point selection

International audienceIn this paper, we propose an improvement of image retrieval for building images using the Bag of Words (BoW) model. The principle consists of pre-processing the interest points detected on the images in order to classify them into two classes, corresponding to building and no-building key points. In this way, the data involved for comparisons is reduced to only the relevant one and only the features describing the buildings are taken into account. The experimental results, carried out on the Paris6k data set shows significant improvement in terms of retrieval performance

Optimization des algorithmes de calibration sur plate-forme embarquée manycore

International audienceThis paper presents the porting and the optimization of full polarization, direction independent calibration algorithm for radio-interferometry, on an embedded many-core platform. In astronomy, calibration algorithms consist of solving for the unknown complex antenna gains using a known model of the sky. Calibration is a key computation to provide images of the sky at good quality and high resolutions. In the context of the Square Kilometer Array (SKA) project, real-time and low power execution of the calibration is challenging. In this paper, we show that the CohJohnes algorithm provides good properties for being executed efficiently on the new generation of many-core embedded platforms. Experimental results are provided using the Kalray MPPA Bostan platform running 288 64-bit VLIW cores and delivering up to 845 GFLOPS at 12W.Le papier présente le portage et l'optimisation d'un algorithme calibration polarisé et indépendant de la direction pour des outils de radio interférométrie sur une plate-forme embarquée manycore. En radioastronomie, les algorithmes de calibration ont pour objectif de trouver les gains complexes inconnus des antennes à partir d'un modèle connu du ciel. La calibration est une étape primordiale permettant de fournir des images du ciel de bonne qualité et à haute-résolution. Dans le contexte du projet SKA (Square Kilometer Array), le challenge est de calculer ces algorithmes de calibration en temps-réel et à faible consommation électrique. Dans ce papier, nous montrons que les algorithmes de CohJohnes ont de bonnes propriétés pour être exécutées efficacement sur la nouvelle generation de processeurs embarqués manycores. Les résultats expérimentaux présentés montrent que les 288 coeurs VLIW 64-bits de la plateforme MPPA Bostan peuvent être utilisés générant 845 GFLOPS pour une consommation de 12W

Associations de l'ivermectine et de la diéthylcarbamazine pour obtenir un meilleur contrôle de l'infection en filariose lymphatique

Depuis I993, une étude en double aveugle a été organisée en Polynésie française pour comparer l'efficacité de doses uniques annuelles de diéthylcarbamazine 6 mg/kg (DEC 6), d'ivermectine 400 μg/kg (IVR 400) et de l'association IVR 400 + DEC 6 dans le traitement de la filariose lymphatique ; 57 porteurs de microfilaires ont été répartis en 3 groupes de traitement de 19 sujets chacun. Douze mois après le premier puis le deuxième traitements (M12 puis M24) respectivement, 3 (16 %) puis 10 (53%), 3 (l6 %) puis 5 (26 %), 7 (37 %) puis 10 (53 %) des porteurs se sont négatives dans les groupes DEC 6, IVR 400 et IVR 400 + DEC 6. La microfilarémie résiduelle est significativement plus basse dans le groupe IVR + DEC (2 % à M12 puis à M24) que dans le groupe DEC 6 (15 % à M12 puis 4% à M24) et le groupe IVR 400 (12 % à M12 puis 10% à M24). L'association IVR + DEC en doses annuelles répétées permettra un meilleur contrôle de l'endémie filarienne, mais pour obtenir le meilleur impact possible, un programme de lutte devra lui associer l'usaqe quotidien d'un sel de table enrichi à la DEC

The Changing Face of Artificial Urinary Sphincter Use in France The Future is Female

International audienceAnalyzing concurrently data from the manufacturer and from a national comprehensive administrative claim database (PMSI)we found that, overall, the total number of AUS implanted (male+female) increased from 2012 to 2017 (+8.8%). This growth was driven by a strong increase in the number of female implants from 2015 to 2017 (+28.9%). Meanwhile, the number of AUS implanted in male patients remained roughly stable and the total number of anti-incontinence surgery in men (slings+AUS) decreased steadily over the period studied