Vulnérabilités liées à l'eau dans les Andes vénézuéliennes : influences des relations sociétés/hydrosystèmes dans le cas de Santa-Cruz-de-Mora

International audienceDes mutations agricoles sont survenues au cours des dernières décennies dans les Andes vénézuéliennes. Cette région autrefois grande productrice de café a vu sa production baisser au profit du maraîchage irrigué et du pastoralisme. Nous avons mené 2 démarches parallèles : la caractérisation des changements d'occupation du sol afin de mettre en perspective le discours des habitants ; et l'analyse des représentations sociales des risques liés à l'eau, restitués plus largement dans les représentations des hydrosystèmes

Validation of 2006 WHO Prediction Scores for True HIV Infection in Children Less than 18 Months with a Positive Serological HIV Test

All infants born to HIV-positive mothers have maternal HIV antibodies, sometimes persistent for 18 months. When Polymerase Chain Reaction (PCR) is not available, August 2006 World Health Organization (WHO) recommendations suggest that clinical criteria may be used for starting antiretroviral treatment (ART) in HIV seropositive children <18 months. Predictors are at least two out of sepsis, severe pneumonia and thrush, or any stage 4 defining clinical finding according to the WHO staging system.From January 2005 to October 2006, we conducted a prospective study on 236 hospitalized children <18 months old with a positive HIV serological test at the national reference hospital in Kigali. The following data were collected: PCR, clinical signs and CD4 cell count. Current proposed clinical criteria were present in 148 of 236 children (62.7%) and in 95 of 124 infected children, resulting in 76.6% sensitivity and 52.7% specificity. For 87 children (59.0%), clinical diagnosis was made based on severe unexplained malnutrition (stage 4 clinical WHO classification), of whom only 44 (50.5%) were PCR positive. Low CD4 count had a sensitivity of 55.6% and a specificity of 78.5%.As PCR is not yet widely available, clinical diagnosis is often necessary, but these criteria have poor specificity and therefore have limited use for HIV diagnosis. Unexplained malnutrition is not clearly enough defined in WHO recommendations. Extra pulmonary tuberculosis (TB), almost impossible to prove in young children, may often be the cause of malnutrition, especially in HIV-affected families more often exposed to TB. Food supplementation and TB treatment should be initiated before starting ART in children who are staged based only on severe malnutrition

Validation of 2006 WHO Prediction Scores for True HIV Infection in Children Less than 18 Months with a Positive Serological HIV Test

All infants born to HIV-positive mothers have maternal HIV antibodies, sometimes persistent for 18 months. When Polymerase Chain Reaction (PCR) is not available, August 2006 World Health Organization (WHO) recommendations suggest that clinical criteria may be used for starting antiretroviral treatment (ART) in HIV seropositive children <18 months. Predictors are at least two out of sepsis, severe pneumonia and thrush, or any stage 4 defining clinical finding according to the WHO staging system.From January 2005 to October 2006, we conducted a prospective study on 236 hospitalized children <18 months old with a positive HIV serological test at the national reference hospital in Kigali. The following data were collected: PCR, clinical signs and CD4 cell count. Current proposed clinical criteria were present in 148 of 236 children (62.7%) and in 95 of 124 infected children, resulting in 76.6% sensitivity and 52.7% specificity. For 87 children (59.0%), clinical diagnosis was made based on severe unexplained malnutrition (stage 4 clinical WHO classification), of whom only 44 (50.5%) were PCR positive. Low CD4 count had a sensitivity of 55.6% and a specificity of 78.5%.As PCR is not yet widely available, clinical diagnosis is often necessary, but these criteria have poor specificity and therefore have limited use for HIV diagnosis. Unexplained malnutrition is not clearly enough defined in WHO recommendations. Extra pulmonary tuberculosis (TB), almost impossible to prove in young children, may often be the cause of malnutrition, especially in HIV-affected families more often exposed to TB. Food supplementation and TB treatment should be initiated before starting ART in children who are staged based only on severe malnutrition

Characterization of the Arabidopsis thaliana 2-Cys peroxiredoxin interactome

This document is the Accepted Manuscript of the following article: Delphine Cerveau, et al, ‘Characterization of the Arabidopsis thaliana 2-Cys peroxiredoxin interactome’, Plant Science, Vol. 252, pp. 30-41, July 2016, doi: https://doi.org/10.1016/j.plantsci.2016.07.003. This manuscript version is distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License CC BY NC-ND 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited, and is not altered, transformed, or built upon in any way.Peroxiredoxins are ubiquitous thiol-dependent peroxidases for which chaperone and signaling roles havebeen reported in various types of organisms in recent years. In plants, the peroxidase function of thetwo typical plastidial 2-Cys peroxiredoxins (2-Cys PRX A and B) has been highlighted while the otherfunctions, particularly in ROS-dependent signaling pathways, are still elusive notably due to the lack ofknowledge of interacting partners. Using an ex vivo approach based on co-immunoprecipitation of leafextracts from Arabidopsis thaliana wild-type and mutant plants lacking 2-Cys PRX expression followedby mass spectrometry-based proteomics, 158 proteins were found associated with 2-Cys PRXs. Alreadyknown partners like thioredoxin-related electron donors (Chloroplastic Drought-induced Stress Proteinof 32 kDa, Atypical Cysteine Histidine-rich Thioredoxin 2) and enzymes involved in chlorophyll synthe-sis (Protochlorophyllide OxidoReductase B) or carbon metabolism (Fructose-1,6-BisPhosphatase) wereidentified, validating the relevance of the approach. Bioinformatic and bibliographic analyses allowedthe functional classification of the identified proteins and revealed that more than 40% are localized inplastids. The possible roles of plant 2-Cys PRXs in redox signaling pathways are discussed in relation withthe functions of the potential partners notably those involved in redox homeostasis, carbon and aminoacid metabolisms as well as chlorophyll biosynthesis.Peer reviewe

Introduction

International audienceInitiée lors du 7e CEISAL dans le cadre du symposium « Hacer frente a los riesgos naturales y ambientales en los espacios rurales y urbanos latinoamericanos : características y factores de mutación de las vulnerabilidades sociales » la réflexion sur les vulnérabilités liées à l’eau dans les Amériques s’est matérialisée dans le cadre de l’appel à contribution de ce n° 4 de la Revue ORDA dans sa nouvelle version. Ce sont les principaux résultats de cette réflexion que nous proposons d’exposer ici.Cette réflexion est motivée par le constat de la persistance, voire de l’augmentation des catastrophes liées à l’eau (pollutions, sécheresses, inondations) dans un monde de plus en plus apte techniquement à agir sur les aléas. Nombreuses et diverses sont les situations qui mettent en effet en lumière la forte vulnérabilité des sociétés face à ce type de risque. Si l’anthropisation des aléas (inondation par ruissellement urbain, contamination anthropique des eaux, assèchement de zones humides,etc.) est incontestable et constitue un facteur aggravant, la part de la vulnérabilité sociale dans l’occurrence des catastrophes est aujourd’hui reconnue comme un facteur déterminan

The Financial Aspects behind Designing a Wind Turbine Generator

This article investigates the construction of a wind power generator requiring the lowest possible cost. The proposed model is an Axial Flux Permanent Magnet (AFPM) Synchronous Machine, which contains two iron rotors and a coreless stator between them, constructed from resin. The scientific contribution relates to the coupling of economic and technical parameters, which will clarify the feasibility, i.e., a wind turbine construction capable of producing approximately 3.5 KW, using a simple mill and a generator of nominal rotor speed 100 rpm. Such studies are few in international literature and mainly concern low levels of rotor speed in relation to the produced output power. For the generator dimensioning, analytical equations are used, while the type and the dimensions of the magnets are determined, before the start of dimensioning. The authors carried out research in the international market, ending up with specific cost-effective magnets, while trying to adjust the remaining dimensions and materials of the machine based on these cost-effective magnets and the aforementioned nominal values of the generator. The machine, whose dimensions are derived by analytical equations, was simulated and analyzed using the Two-Dimensional Finite Element Method (2D-FEM) and the Three-Dimensional Finite Element Method (3D-FEM), for comparison purposes. Moreover, an economic analysis of the generator and its individual parts was conducted. Finally, a novel idea for reducing the total generator cost is proposed, by replacing the rotor disks with rings. The investigation revealed that analytical equations can predict with satisfactory accuracy the generator’s parameters. In addition, as permanent magnets are the most expensive materials in the construction, their predetermination using low-cost magnets can reduce the construction cost. Finally, the proposed concept of a ring-shaped rotor instead of a disk rotor, provides a cost reduction of up to 20%

Nickel solubility and precipitation in soils : A thermodynamic study

The formation of mixed-metal-Al layered double hydroxide (LDH) phases similar to hydrotalcite has been identified as a significant mechanism for immobilization of trace metals in some environmental systems. These precipitate phases become increasingly stable as they age, and their formation may therefore be an important pathway for sequestration of toxic metals in contaminated soils. However, the lack of thermodynamic data for LDH phases makes it difficult to model their behavior in natural systems. In this work, enthalpies of formation for Ni LDH phases with nitrate and sulfate interlayers were determined and compared to recently published data on carbonate interlayer LDHs. Differences in the identity of the anion interlayer resulted in substantial changes in the enthalpies of formation of the LDH phases, in the order of increasing enthalpy carbonate<sulfate<nitrate. Substitution of silica for carbonate resulted in an even more exothermic enthalpy of formation, confirming that silica substitution increases the stability of LDH precipitates. Both mechanical mixture and solid-solution models could be used to predict the thermodynamic properties of the LDH phases. Modeling results based on these thermodynamic data indicated that the formation of LDH phases on soil mineral substrates decreased Ni solubility compared to Ni(OH) over pH 5 - 9 when soluble Al is present in the soil substrate. Over time, both of these precipitate phases will transform to more stable Ni phyllosilicates