141 research outputs found
Analysis of layering-related linear features on comet 67P/Churyumov-Gerasimenko
We analysed layering-related linear features on the surface of comet
67P/Churyumov-Gerasimenko (67P) to determine the internal configuration of the
layerings within the nucleus. We used high-resolution images from the OSIRIS
Narrow Angle Camera onboard the Rosetta spacecraft, projected onto the SHAP7
shape model of the nucleus, to map 171 layering-related linear features which
we believe to represent terrace margins and strata heads. From these curved
lineaments, extending laterally to up to 1925 m, we extrapolated the subsurface
layering planes and their normals. We furthermore fitted the lineaments with
concentric ellipsoidal shells, which we compared to the established shell model
based on planar terrace features. Our analysis confirms that the layerings on
the comet's two lobes are independent from each other. Our data is not
compatible with 67P's lobes representing fragments of a much larger layered
body. The geometry we determined for the layerings on both lobes supports a
concentrically layered, `onion-shell' inner structure of the nucleus. For the
big lobe, our results are in close agreement with the established model of a
largely undisturbed, regular, concentric inner structure following a generally
ellipsoidal configuration. For the small lobe, the parameters of our
ellipsoidal shells differ significantly from the established model, suggesting
that the internal structure of the small lobe cannot be unambiguously modelled
by regular, concentric ellipsoids and could have suffered deformational or
evolutional influences. A more complex model is required to represent the
actual geometry of the layerings in the small lobe
Recalage de modèle éléments finis utilisant une fonction coût géométrique pour l'identification de paramètres matériau en dynamique transitoire.
Pour identifier la valeur de paramètres matériaux, on réalise des essais normalisés sur des éprouvettes du matériau considéré. Dans ce travail, nous introduisons une nouvelle méthode numérique pour l'identification de paramètres de matériau hyperélastique dans un cadre de dynamique transitoire. Nous nous intéressons particulièrement aux méthodes d'identification basées sur des mesures de champs sans contact. Dans cette situation, on peut citer une technique très utilisée, la corrélation d'images numériques, qui permet l'obtention de champs de déplacement. En utilisant une procédure basée sur un recalage de modèle par éléments finis (Finite Element Model Updating), on propose ici une nouvelle famille de fonctions coûts basées sur la géométrie uniquement. Notre objectif est d'éviter l'utilisation de la corrélation d'images numériques qui est nécessaire lorsque l'on utilise une fonction coût basée sur le déplacement. Le résultat des mesures expérimentales consiste en une succession d'images. Ainsi, la méthode introduite dans nos travaux ne repose que sur une méthode simple de segmentation d'images au lieu d'une technique de corrélation d'images numériques. Cet avantage est rendu possible par l'utilisation d'une nouvelle fonction coût basée sur des quantités géométriques. Les performances de la méthode proposée pour des problèmes en dynamique transitoire où le flux d'information peut devenir très important, et où il est intéressant de n'extraire que l'information essentielle. Des exemples numériques basés sur des données synthétiques permettent de mesurer la précision et la robustesse de l'approche introduite
Effects of incorporation levels of Pueraria phaseoloides leaf flour on carcass characteristics and chemical composition of meat from local rabbit (Oryctolagus cuniculus) in South-East Gabon
The objective of this study was to contribute in improving knowledge on rabbit feeding in Gabon. This work was conducted with the aim of studying carcass characteristics and chemical composition of meat from rabbit induced by feeds containing P. phaseoloides. To that effect, 20 young female rabbits from local breed, weighing averagely 611 ± 33.20 g and aged about 6 weeks were randomly distributed in 4 groups of 5 animals each. The groups R0, R15, R20 and R25 were fed rations containing respectively 0%, 15%, 20% and 25% of P. phaseoloides. At the end of the trial, animals were slaughtered then eviscerated in order to evaluate carcass characteristics. Muscles were taken, ground and mixed for chemical analysis. No matter the ration, carcass characteristics showed no significant difference (p > 0.05). Highest protein contents in meat were recorded in animals from R15 (23.90% DM) and R20 (22.46% DM). The lowest fat content (5.41% DM) was that of animals from R25, followed by that from R20 (6.67% DM). Based on these results obtained, the ration containing 20% Pueraria phaseolides (R20) could be recommended
Endemic Human Monkeypox, Democratic Republic of Congo, 2001–2004
By analyzing vesicle fluids and crusted scabs from 136 persons with suspected monkeypox, we identified 51 cases of monkeypox by PCR, sequenced the hemagglutinin gene, and confirmed 94% of cases by virus culture. PCR demonstrated chickenpox in 61 patients. Coinfection with both viruses was found in 1 additional patient
Usefulness of Noninvasive Predictors of Oesophageal Varices in Black African Cirrhotic Patients in Côte d'Ivoire (West Africa)
Aims. To determine the usefulness of platelet count (PC), spleen diameter (SD) and platelet count/spleen diameter ratio (PC/SD ratio) for the prediction of oesophageal varices (OV) and large OV in black African patients with cirrhosis in Côte d’Ivoire. Materials and Methods. Study was conducted in a training sample (111 patients) and in a validation sample (91 patients). Results. Factors predicting OV were sex: (OR=0.08, P=0.0003), PC (OR = 12.4, P=0.0003), SD (OR = 1.04, P=0.002) in the training sample. The AUROCs (±SE) of the model (cutoff ≥ 0.6), PC (cutoff 140) and PC/SD ratio (cutoff ≤ 868) were, respectively; 0.879 ± 0.04, 0.768 ± 0.06, 0.679 ± 0.06, 0.793 ± 0.06. For the prediction of large OV, the model’s AUROC (0.850 ± 0.05) was superior to that of PC (0.688 ± 0.06), SD (0.732 ± 0.05) and PC/SD ratio (0.752 ± 0.06). In the validation sample, with PC, PC/SD ratio and the model, upper digestive endoscopy could be obviated respectively in 45.1, 45.1, and 44% of cirrhotic patients. Prophylactic treatment with beta blockers could be started undoubtedly respectively in 36.3, 41.8 and 28.6% of them as having large OV. Conclusion. Non-invasive means could be used to monitor cirrhotic patients and consider treatment in African regions lacking endoscopic facilities
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
Ebola Virus Neutralizing Antibodies Detectable in Survivors of theYambuku, Zaire Outbreak 40 Years after Infection.
The first reported outbreak of Ebola virus disease occurred in 1976 in Yambuku, Democratic Republic of Congo. Antibody responses in survivors 11 years after infection have been documented. However, this report is the first characterization of anti-Ebola virus antibody persistence and neutralization capacity 40 years after infection. Using ELISAs we measured survivor's immunological response to Ebola virus Zaire (EBOV) glycoprotein and nucleoprotein, and assessed VP40 reactivity. Neutralization of EBOV was measured using a pseudovirus approach and plaque reduction neutralization test with live EBOV. Some survivors from the original EBOV outbreak still harbor antibodies against all 3 measures. Interestingly, a subset of these survivors' serum antibodies could still neutralize live virus 40 years postinitial infection. These data provide the longest documentation of both anti-Ebola serological response and neutralization capacity within any survivor cohort, extending the known duration of response from 11 years postinfection to at least 40 years after symptomatic infection
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
Cent scientifiques répliquent à SEA (Suppression des Expériences sur l’Animal vivant) et dénoncent sa désinformation
La lutte contre la maltraitance animale est sans conteste une cause moralement juste. Mais elle ne justifie en rien la désinformation à laquelle certaines associations qui s’en réclament ont recours pour remettre en question l’usage de l’expérimentation animale en recherche
ACR Appropriateness Criteria® pulsatile abdominal mass, suspected abdominal aortic aneurysm
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