Influence of thermal fluctuations on the Nernst signal in superconducting (K,Ba)BiO3 single crystals

International audienceWe report on the Nernst effect, specific heat and transportmeasurements performed in high quality (K,Ba)BiO3 single crystals close to optimal doping (Tc ∼ 31 K). We show that a nonzero Nernst effect remains visible well above the upper critical field unambiguously deduced from the onset of the specific heat anomaly. This finite Nernst signal is attributed to fluctuations of the amplitude of the order parameter in a region where the free energy is smaller than kBT . Despite the absence of any vortex liquid phase (and hence of any significant phase fluctuations), the field and temperature dependence of the Nernst coefficient is very similar to the one obtained in electron-doped cuprates

Prognosis of umbilical cord prolapse: experiency of an African maternity

Background: Assess the fetal prognosis of umbilical cord prolapse (UCP) at Cocody University Hospital.Methods: It was a cross-sectional, descriptive and case-control study about 92 cases of umbilical cord prolapse beating. It took place over a period of 3 years from 1 January 2013 to 31 December 2015.Results: The frequency of the umbilical cord prolapse beating was 0.73%. The patients came from other maternity in 84.8%. Upon arrival in our maternity, therapeutic attitude was dominated by the positioning of Trendelenburg (73.9%). The c-section was performed in 63% of cases. The fetal prognosis was bad; neonatal mortality was 41.3% at 5 minutes of life against 9.8% in the control group. The factors aggravating the fetal prognosis were the long delay between the occurrence of the umbilical cord prolapse and childbirth, the delivery mode and the small birth weight.Conclusions: The late management and the evacuations negatively affect the fetal prognosis. Improving fetal prognosis requires quick care and the provision of an efficient technical platform surrounding maternity.

Integrated Water Resources Management on the Southern Slope of the Bamboutos Mountains: Issues Related, Challenges and Prospects

This research on water resource management was carried out on the southern slope of the Bamboutos Mountains. The main objective of this study was to contribute to a better knowledge and understanding of the problems related to the exploitation of water resources on the southern slope of the Bamboutos Mountains in the hope of finding appropriate management strategies. More specifically, it was a matter of identifying the stakeholders involved in the exploitation of water resources on the southern slope of the Bamboutos Mountains, identifying the problems related to the exploitation of water resources on the said slope, determining the causes and consequences of the problems related to the exploitation of the said resource and finally identifying the strategies, as well as their strengths and weaknesses used by local populations to manage the problems related to the use of water resources. Access to secondary data, and semi-structured surveys allowed the study to be conducted. This study shows that the main actors involved in the exploitation of water resources are farmers, households, industries and finally ranchers. The main problems related to the exploitation of the resource on the said slope have been identified as: conflicts of use (48.60%), water-related diseases (21.30%), distance (18%) and finally the scarcity of the resource (11.90%). These problems have as their causes and consequences respectively: overexploitation of the resource (47.30%), climatic variations (21%), pollution of watercourses (30.40%), struggle between users (54.97%), difficulty of supply (20.50%), and decline in both agricultural and domestic activities (24.53%). In order to solve these problems, local populations have developed strategies ranging from agreement to friendly resolution of conflict problems, construction of health centers for waterborne diseases and construction of alternative and closer supply points to solve distance problems. Despite all these measures, these populations are still struggling to cope with problems that affect their daily well-being.   

Evaluation de l’Effet des Eaux Usées Industrielles sur la Qualité de l’Eau de la Rivière Klou au Centre du Bénin

La présente étude a pour objectif d’évaluer l’impact des eaux usées industrielles sur la qualité de l’eau de la rivière Klou. Pour cela, des prélèvements d’eau ont été effectués avec une fréquence mensuelle sur des stations témoins et exposées. Les analyses physico-chimiques et le calcul de l’indice de Pollution Organique (IPO) ont été effectués. En période pluvieuse, les valeurs des paramètres physico-chimiques (pH, conductivité, TDS, ammonium, DBO5, nitrate, nitrite et orthophosphates) etaient faibles. De plus, les fortes valeurs des paramètres étudiés sont observées sur les stations plus exposées. Les résultats de l’analyse en composantes principales (ACP) sur les paramètres physico-chimiques ont révélé deux groupes  de stations. Le premier est constitué des deux stations témoins caractérisées par les faibles valeurs des paramètres étudiés alors que le second est composé des stations plus exposées et celles de l’aval avec les fortes valeurs des paramètres étudiés. L’indice de pollution organique a révélé une pollution modérée au niveau des stations témoins et une pollution organique forte et très forte respectivement au niveau des stations plus exposées et celles de l’aval. Il est nécessaire alors de mettre en place une politique de  restauration de la qualité écologique des eaux de cette rivière et des centres d’épuration opérationnels et efficaces.   The objective of this study was to assess the impact of industrial wastewater on the water quality of the Klou River. For this purpose, water sampling was conducted with a monthly frequency on control and exposed stations. Physico-chemical analyses and the calculation of the Organic Pollution Index (IPO) were carried out. In rainy periods, the values of the physico-chemical parameters (pH, conductivity, TDS, ammonium, BOD5, nitrate, nitrite and orthophosphates) were low. Moreover, the high values of the studied parameters were observed at the more exposed stations. The results of the principal component analysis (PCA) on the physico-chemical parameters revealed two groups of stations. The first consists of the two control stations characterized by low values of the studied parameters, while the second consists of the more exposed stations and those downstream with high values of the studied parameters. The organic pollution index revealed moderate pollution at the control stations and strong and very strong organic pollution respectively at the more exposed stations and those downstream. It is then necessary to put in place a mechanism to restore the ecological quality of the waters of this river and operational and effective purification centres

Etude Préliminaire de la Diversité et de la Structure du Peuplement Zooplanctonique de la Rivière Okpara au Bénin

La présente étude a pour objectif d’évaluer la diversité et la structure du zooplancton dans la rivière Okpara. Le zooplancton de la rivière a été identifié et la structure de sa communauté évaluée dans neuf stations sélectionnées grâce à la richesse taxonomique, à la densité, à l’indice de diversité de Shannon et l’indice d’équitabilité de Piélou. Un total de 68 espèces de zooplancton a été enregistré, réparties en trois groupes : comprenant des rotifères (57), des copépodes (07) et des cladocères (04). Le nombre d’espèces a été plus élevé dans le cours inférieur, que dans le cours supérieur et dans le cours moyen. Les rotifères représentent les groupes les plus abondant avec 78,25 % de l'abondance totale, suivis des copépodes (20,7 %) et des cladocères (1,3 %). Keratella valga et Tropocyclops confinis sont les espèces les plus abondantes. Mytilina sp., Asplanchna girodi, Anuraeopsis sp., Lepadella sp., Asplanchna brightwellii, Asplanchna navicular, Trichocerca sp. et Trichocerca tenuior ont été enregistrés sur toutes les stations. Les valeurs moyennes d’abondance et de densité moyenne du zooplancton sont plus élevées en saison sèche qu’en saison pluvieuse. Les valeurs de la richesse, de l’indice de diversité de Shannon et d’équitabilité de Piélou sont plus élevées en saison pluvieuse qu’en saison sèche. La forte présence de certaines espèces indicatrices de pollution telles que Asplanchna brightwelli, Brachionus angularis, Brachionus falcatus pourrait indiquer la présence de polluants organiques dans la rivière. Il est donc nécessaire de mettre en place des mesures de surveillance efficaces afin de protéger la rivière de toute intrusion anthropogénique.   The objective of this study was to assess the diversity and structure of zooplankton in the Okpara River. The river's zooplankton were identified and their community structure assessed at nine selected stations using taxonomic richness, density, the Shannon diversity index and the Pielou equitability index. A total of 68 species of zooplankton were recorded, divided into three groups: rotifers (57), copepods (07) and cladocerans (04). The number of species was higher in the lower reaches than in the upper and middle reaches. Rotifers were the most abundant group with 78.25% of the total abundance, followed by copepods (20.7%) and cladocerans (1.3%). Keratella valga and Tropocyclops confinis were the most abundant species. Mytilina sp., Asplanchna girodi, Anuraeopsis sp., Lepadella sp., Asplanchna brightwellii, Asplanchna navicular, Trichocerca sp. and Trichocerca tenuior were recorded at all stations. The values for abundance and density of zooplankton are higher in the dry season than in the rainy season. The values for species richness, Shannon diversity index and Pielou equitability are higher in the wet season than in the dry season. The strong presence of certain pollution indicator species such as Asplanchna brightwelli, Brachionus angularis and Brachionus falcatus could indicate the presence of organic pollutants in the river. Effective monitoring measures therefore need to be put in place to protect the river from anthropogenic intrusion

Challenges to Validate Multi-physics Model of Liver Tumor Radiofrequency Ablation from Pre-clinical Data

International audienceThe planning and interventional guidance of liver tumor ra-diofrequency ablation (RFA) is difficult due to the cooling effect of large vessels and the large variability of tissue parameters. Subject-specific modeling of RFA is challenging as it requires the knowledge of model geometry and hemodynamics as well as the simulation of heat transfer and cell death mechanisms. In this paper, we propose to validate such a model from pre-operative multi-modal images and intra-operative signals (temperature and power) measured by the ablation device itself. In particular , the RFA computation becomes subject-specific after three levels of personalization: anatomical, heat transfer and a novel cellular necro-sis model. We propose an end-to-end pre-clinical validation framework that considers the most comprehensive dataset for model validation. This framework can also be used for parameter estimation and we evaluate its predictive power in order to fully assess the possibility to personalize our model in the future. Such a framework would therefore not require any necrosis information, thus better suited for clinical applications. We evaluated our approach on seven ablations from three healthy pigs. The predictive power of the model was tested: a mean point to mesh error between predicted and actual ablation extent of 3.5 mm was achieved

Comprehensive Pre-Clinical Evaluation of a Multi-physics Model of Liver Tumor Radiofrequency Ablation

International audiencePurpose: We aim at developing a framework for the validation of a subject-specific multi-physics model of liver tumor radiofrequency ablation (RFA). Methods: The RFA computation becomes subject-specific after several levels of personalization: geometrical and biophysical (hemodynamics, heat transfer and an extended cellular necrosis model). We present a comprehensive experimental setup combining multi-modal, pre-and post-operative anatomical and functional images, as well as the interventional monitoring of intra-operative signals: the temperature and delivered power. Results: To exploit this data set, an efficient processing pipeline is introduced, which copes with image noise, variable resolution and anisotropy. The validation study includes twelve ablations from five healthy pig livers: a mean point-to-mesh error between predicted and actual ablation extent of 5.3 ± 3.6 mm is achieved. Conclusion: This enables an end-to-end pre-clinical validation framework that considers the available data set

Évaluation de la teneur en vitamine A et de l’indice de peroxyde des huiles végétales couramment vendues dans les marchés au Burkina Faso

La carence en vitamine A constitue un problème de santé publique dans les pays en développement et affecte en particulier les jeunes enfants et les femmes en âge de procréer. Le but de cette étude était d'évaluer l’application de la politique nationale en matière de production et d’importation, des huiles végétales raffinées, d’enrichissement obligatoire en vitamine A au Burkina Faso, à travers la détermination de la teneur en vitamine A et de l'indice de peroxyde des huiles végétales vendues sur le marché. Cette étude transversale a été menée dans cinq villes sélectionnées selon la densité de la population. Cinquante-neuf échantillons d’huile ont été achetés dans ces villes pour évaluer la teneur en vitamine A, l'indice de peroxyde et leur conformité aux normes nationales et internationales. Dans l'ensemble, 76,27% des huiles n'étaient pas suffisamment enrichies en vitamine A. Pour l'indice de peroxyde, 3,39% des huiles n'étaient pas conformes. Globalement, 77,97% des huiles n'étaient pas conformes pour ces deux paramètres. Au regard de ces résultats il est nécessaire d’intensifier la lutte contre la mise à la consommation des huiles non enrichies en vitamine A au Burkina Faso. English title: valuation of the vitamin A content and the peroxide value of vegetable oils commonly sold in markets in Burkina Faso Vitamin A deficiency is a public health problem in developing countries and particularly affects young children and women of childbearing age. The aim of this study was to assess the implementation of the national policy on the production and importation of refined vegetable oils and mandatory vitamin A fortification in Burkina Faso, through the determination of the vitamin A content and peroxide value of vegetable oils sold on the market. A cross-sectional study was conducted in five cities selected according to population density. Fifty-nine oil samples were purchased in these cities to assess vitamin A content, peroxide value and compliance with national and Codex standards. Overall, 76.17% of the oils were not adequately fortified with vitamin A. For the peroxide value, 3.39% of the oils did not comply. Overall, 77.97% of the oils did not comply for these two parameters. In view of these results, it is necessary to intensify the fight against the consumption of oils not enriched in vitamin A in Burkina Faso