Immunologie génétique de la résistance humaine au paludisme à P. Falciparum (Rôle des sous-classes d'IgG dans la protection. Contrôle génétique de la charge parasitaire sanguine et de la réponse immune spécifique)

AIX-MARSEILLE2-BU Sci.Luminy (130552106) / SudocSudocFranceF

Tropical cyclone induced wave setup around New Caledonia during Cyclone COOK (2017)

Tropical cyclone (TC)-induced coastal flooding arises from a combination of atmospheric surge, and energetic wave-induced setup. TC-generated waves in deep water considerably evolve in shallow water before reaching the coast. Islands surrounded by a barrier reef and lagoon are a particular case of steep and irregular bathymetry over which waves undergo various transformations, and induce complex wave-current interactions. The present study investigates the TC-induced coastal impact on the reef environment of New Caledonia in the tropical southwest Pacific. An unstructured wave-current model simulation encompassing New Caledonia and Vanuatu is used to describe the complete TC-induced waves impact, from wave generation to propagation and transformation in the coastal area. Comparison with in-situ measurements are performed during cyclone COOK in 2017. The results show that coastlines with a double protection (barrier and fringing reefs) are relatively sheltered from the waves induced by TCs (significant wave height is 3 m at the coast vs. 13 m offshore) while shores fronting the reef passes are more severely exposed with waves reaching 9 m close to the coast. Setups and currents that are associated to wave breaking on the barrier reef induce strong lagoon currents and localized sea level anomalies that does not necessarily reach the coast. In more sheltered bays, wave breaking at the entrance of the bay acts against outgoing currents. This phenomenon leads to an additional elevation of the mean water level in the bay

Haptoglobin genotypes are not associated with resistance to severe malaria in The Gambia.

The influence of haptoglobin polymorphisms on severe malaria occurrence was assessed in 1183 individuals from The Gambia. No significant association was found between severe malaria and either haptoglobin genotypes or phenotypes. The advantages of using a deoxyribonucleic acid-based haptoglobin typing method are discussed

Unveiling the global influence of tropical cyclones on extreme waves approaching coastal areas

International audienceAbstract Tropical and extra-tropical storms generate extreme waves, impacting both nearby and remote regions through swell propagation. Despite their devastating effects in tropical areas, the contribution of tropical cyclones (TCs) to global wave-induced coastal risk remains unknown. Here, we enable a quantitative assessment of TC’s role in extreme waves approaching global coastlines, by designing twin oceanic wave simulations with and without realistic TC wind forcing. We find that TCs substantially contribute to extreme breaking heights in tropical regions (35-50% on average), reaching 100% in high-density TC areas like the North Pacific. TCs also impact remote TC-free regions, such as the equatorial Pacific experiencing in average 30% of its extreme wave events due to TCs. Interannual variability amplifies TC-induced wave hazards, notably during El Niño in the Central Pacific, and La Niña in the South China Sea, Caribbean Arc, and South Indian Ocean coastlines. This research offers critical insights for global risk management and preparedness

Unveiling the global influence of tropical cyclones on extreme waves approaching coastal areas

International audienceAbstract Tropical and extra-tropical storms generate extreme waves, impacting both nearby and remote regions through swell propagation. Despite their devastating effects in tropical areas, the contribution of tropical cyclones (TCs) to global wave-induced coastal risk remains unknown. Here, we enable a quantitative assessment of TC’s role in extreme waves approaching global coastlines, by designing twin oceanic wave simulations with and without realistic TC wind forcing. We find that TCs substantially contribute to extreme breaking heights in tropical regions (35-50% on average), reaching 100% in high-density TC areas like the North Pacific. TCs also impact remote TC-free regions, such as the equatorial Pacific experiencing in average 30% of its extreme wave events due to TCs. Interannual variability amplifies TC-induced wave hazards, notably during El Niño in the Central Pacific, and La Niña in the South China Sea, Caribbean Arc, and South Indian Ocean coastlines. This research offers critical insights for global risk management and preparedness

Association of Fcgamma receptor IIa (CD32) polymorphism with severe malaria in West Africa.

Malaria continues to claim the lives of more children worldwide than any other infectious disease, and improved understanding of disease immunology is a priority for the development of new therapeutic and vaccination strategies. FcgammaRIIa (CD32) contains a polymorphic variant (H/R131) that has been associated with variability in susceptibility to both bacterial diseases and Plasmodium falciparum parasitemia. We investigated the role of this polymorphism in West Africans with mild and severe malarial disease. The HH131 genotype was significantly associated with susceptibility to severe malaria (P = 0.03, odds ratio = 1.40, 95% confidence interval = 1.02-1.91). In contrast to studies of parasitemia, the presence of the R131 allele, rather than the RR131 genotype, appeared to be the important factor in protection from disease. This is the first evidence for an association between CD32 polymorphism and severe malaria and provides an example of balancing selective pressures from different infectious diseases operating at the same genetic locus

The wave regimes of the Central Pacific Ocean with a focus on pearl farming atolls

International audiencePearl farming sustainability in South Central Pacific (SCP) atolls strongly depends on water quality and renewal. These factors are partly controlled by the wave conditions that impact the lagoon circulation. To characterize the wave conditions around 83 SCP atolls including those hosting pearl farming activities, we used 18 years of WaveWatchIII simulation with a grid refined from 50 to 5 km resolution. Three regional wave regimes are statistically identified: two associated with long distant swells originating from mid-latitude storms, and one with local trade winds. All regimes occur with a relatively high frequency (22–44%), but with a marked seasonality. Wave conditions are also strongly modified locally during their propagation between the archipelagoes. Western and southern isolated atolls generally have a single regime all around their rims. In contrast, central Tuamotu atolls experience different regimes depending on their levels of protection. These results help understanding atoll hydrodynamics, which has implications for their management