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Les risques naturels côtiers et l’adaptation au changement climatique à Mayotte : de l’ingénierie côtière à l’ingénierie sociale, quelles perspectives ?
No full textPrésentation dans le cadre du séminaire "Les risques naturels à Mayotte et le secteur associatif" organisé par le réseau EEDD 976, Barakani, Mayott
Emergence of new heat stress hotspots over the West Africa
No full textInternational audienceWe calculate the hourly wet bulb globe temperature (WBGT) values for the last 50 years over Western Africa to assess the emergence of new heatwave hotspots and the interplay between moist and dry heatwaves. In the formulation used, WBGT is derived using the grided data from ERA5 and ERA5-HEAT: 2-m air temperature, relative humidity, 10-m wind speed and mean radiant temperature (a measure of incidence of radiation on a body), and is thus representative of outdoor conditions.We find that the heat stress estimated through WBGT does not peak over the same geographical regions as the air temperature, suggesting an important role of humidity in intensifying heatwaves over certain regions. While the highest temperatures are reached in the northern Sahel and Saharan regions, the highest heat stress values are found further to the south, in the region bordering Senegal, Mauritania and Mali and in southwest Niger. These are the same regions where the WBGT threshold of 33 °C (conditions dangerous even at resting metabolic rates (MR) < 115 W) have recently been crossed for up to 40 hours per year.The duration of exposure to WBGT > 30 °C (conditions dangerous at light physical activity, MR < 180 W) has been increasing over almost the entire West Africa, at rates from 30 to 100 hours/decade. Over the Senegal - Mauritania - Mali border and southern Niger, exposure to WBGT > 33 °C has been increasing by 1-4 hours/decade.Dangerous WBGT thresholds can be crossed at a wide range of temperatures and are often not associated with the highest temperature percentiles. For example, in Niamey, a WBGT of 30 °C has been crossed in the temperature range from ~ 29 to 44 °C, in Thies (Dakar) and Ouagadougou from ~ 28 to 43 °C, and in Abidjan from ~ 28 - 36 °C. In September 2019 and July 2020, in Niamey we find the first occurrences of air temperatures below 36 °C being associated with very dangerous heat stress values (WBGT > 33 ° C).We conclude that for much of continental West Africa, and particularly for the Senegal - Mauritania - Mali border region and southern Niger, extreme heat alerts should at a minimum include indicators accounting for temperature and humidity, in order to capture the dangerous moist heatwave conditions occurring at temperatures well below the highest temperature percentiles. More complex indicators that additionally account for wind and radiation are very desirable for estimates of outdoor safety
Cardiopulmonary Hemodynamic Determinants of Long-Term Survival in Sickle Cell Disease: Insights from the ETENDARD Study
No full textInternational audiencePulmonary hypertension (PH) is a serious cardiopulmonary complication of sickle cell disease (SCD), but the prognostic impact of hemodynamic parameters remains poorly defined
FCGR2A-131R Is Associated with Lupus Nephritis Rather than Non-Lupus Nephritis SLE in an Indigenous African Caribbean Population
No full textInternational audienceFc gamma receptors (FcγRs) control humoral and cellular immune responses and maintain the immune system balance. Functional polymorphisms of FcγRs, whose prevalence was dependent on ethnic origin, were found to be associated with systemic lupus erythematosus (SLE) or kidney injuries in several ethnic groups. We aimed at investigating the association between the functional single-nucleotide polymorphisms (SNPs) of FcγRIIa-H131R (rs1801274), FcγRIIb-I232T (rs1050501), FcγRIIIa-V158F (rs396991) and FcγRIIIb variants (NA1 and NA2) and lupus erythematosus systemic in an indigenous African Caribbean population. We compared the frequencies of the functional SNPs of FCGR2A (FcγRIIa-H131R, rs1801274), FCGR2B (FcγRIIb-I232T, rs1050501), FCGR3A (FcγRIIIa-V158F, rs396991) and FCGR3B variants (FcγRIIIb NA1 and NA2) between lupus and healthy controls in an indigenous African Caribbean population. We highlighted an association between the FCGR3B-NA1/NA1 and FCGR3A-158F alleles and systemic lupus erythematosus, in addition to an association between FCGR2A-131R and lupus nephritis. Furthermore, an increase in the 131R-158V haplotype in lupus nephritis (30.4%) vs. lupus non-nephritis (15.8%) was noticed. Surprisingly, in spite of the high frequency of the FCGR2B-232T allele in our population, our study did not highlight any association of this allele either with SLE or lupus nephritis (a severe and frequent form of SLE). CD72-Hap1, which has been shown to confer resistance to SLE against T232 allele, was not enhanced in the control group. Our results emphasize an association between FCGR2A-131R and lupus nephritis with a distinctive FCGR polymorphism distribution in an indigenous African Caribbean population, confirming the important variation in the FCGR locus depending on ethnic origin
Impact of Tafamidis on survival in elderly patients: Insights from the Healthcare European Amyloidosis Registry
No full textInternational audienceCardiac transthyretin amyloidosis (ATTR-CM) is a life-threatening cardiomyopathy. Tafamidis has been demonstrated to be an effective treatment. Our aim was to analyze clinical characteristics and survival of patients with ATTR-CM aged ≥80 years diagnosed after November 2018, treated with tafamidis 80/61 mg, and compare them with a non-treated group diagnosed before that date
An Irish cocktail of flatworm, earthworm and parasite DNAs: genomics of invasive land flatworms (Geoplanidae) reveal infestations by two new Mitosporidium species (Microsporidia)
No full textInternational audienceAccording to the classical Enemy Release Hypothesis, one reason for the success of invasive species is that they have escaped their predators and parasites during migration to newly invaded territories. In this context, the discovery of any parasite of an invasive species is of particular interest. Here, we report the results of genomic investigations performed on two invasive species of land flatworms (Geoplanidae) collected in Northern Ireland, Kontikia andersoni Jones, 1981, and Australoplana sanguinea (Moseley, 1877). We describe the mitogenomes and paralogous RNA genes of both species. Prey DNA was detected in both flatworm species, providing molecular evidence that their diet includes earthworms. Unexpectedly, we detected sequences assigned to the microsporidian genus Mitosporidium Haag et al., 2015, which, prior to this study, included a single species. Each land flatworm species harboured its own species of Mitosporidium. For nomenclatural reasons, we could not assign binomial names to these species; instead, we designate them as Mitosporidium sp. JL467 (in K. andersoni) and Mitosporidium sp. JL472 (in A. sanguinea). For each new Mitosporidium species, we describe the gene content of the mitogenome and the complete cluster of nuclear ribosomal RNA genes. In the absence of direct evidence of host–parasite relationships, we discuss the possible hosts of these Microsporidia, which could be the flatworms themselves or their prey; the most likely hypothesis is that they are parasites of land flatworms. Other Mitosporidium species should be sought for in native land flatworms from the Australasian region, where the two invasive flatworm species originated. Investigations on the possible pathogenic role of these parasites are needed
LYMPHOSCORE. Nouveau système d’évaluation qualitatif et semi-quantitatif en lymphoscintigraphie des membres inférieurs
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Evaluating the role of ore metamorphism and deformation in the remobilization of critical metals during orogens formation
No full textInternational audienceOrogenic processes, including metamorphism and deformation, can significantly impact the interpretation, understanding and economic value of mineral deposits. Critical metals and metalloids (CMs) such as gallium (Ga), germanium (Ge), indium (In), platinum group elements (PGE), and cobalt (Co) are commonly mined as byproducts of base metals (i.e., Zn, Fe, Cu, Ni). The impact of metamorphism on CMs (re)distribution is frequently overlooked, underestimated or not investigated by adequate and representative analytical procedures. In this review article, we evaluate the importance of metamorphism and deformation on the remobilization of CMs. The timing of ore emplacement relative to orogen formation, mineralogy and ore textures of ca. 170 deposits reported in the literature have been extracted in three continental districts (Australia, China, and Europe). This synthesis shows that metamorphism frequently overprints ore deposits and might create favorable conditions for the redistribution of CMs within ore minerals. Orogenic minerals rich in CMs can be broadly defined as the large-scale remobilization or sample-scale redistribution product of pre-existing CMs concentrations, present in the primary ore, driven by metamorphism and/or tectonic processes. Contrasting behaviors for the formation of orogenic minerals rich in CMs is described in the literature. Under low-to medium-grade conditions (<450 • C; <2-3kbar), Ge-rich orogenic minerals are generally well preserved while In, Co-PGE-rich orogenic minerals form newly at higher temperature (> 450 • C). In several sulfides potentially rich in CMs, experimental and natural observations have demonstrated ductile behavior at low grades (~100-200 • C; <2kbar), which may affect the distribution of CMs in sulfide ore. This review highlights the challenges ore geologists face in apprehending primary signatures in sulfide minerals within systems affected by secondary orogenic events as well as the potential of CMs system analysis in understanding the conditions of ore (de)formation
Remote sensing and spatial modelling. Applications to the surveillance and control of mosquito-borne diseases
No full textSource Agritrop Cirad (https://agritrop.cirad.fr/615033/)International audienceMosquitoes are vectors of many disease-causing pathogens, including malaria, dengue, chikungunya, and yellow fever. According to the World Health Organization, these vector-borne diseases account for several hundred thousand deaths annually. They also cause zoonoses, such as Rift Valley fever and West Nile fever. In this context, the development of operational tools to support surveillance and control strategies is essential—not only in countries of the Global South, where mosquito-borne diseases are most prevalent in tropical and subtropical regions, but also in the countries of the North, where the establishment of invasive species such as the tiger mosquito is increasing the risk of disease emergence. To address these challenges, Earth observation imagery offers valuable potential: the spatial distribution and seasonal dynamics of mosquito populations are closely linked to climatic factors (such as temperatures, rainfall, and humidity) and environmental variables (such as the presence of water bodies and vegetation), many of which can be monitored through satellite data. Numerous recent studies have led to the development of innovative methods that combine remote sensing with spatial modelling to predict the spatial and temporal dynamics of vector mosquitoes and associated diseases. Moving beyond proof-of-concept, some of these approaches have given rise to operational tools and processing chains that are now actively used by public health authorities and vector control agencies. This book, intended for students, researchers, and public health professionals, offers a synthesis of current research and operational tools in the field