This project aims at understanding the movement and intensity variations of single vortices, which we produce in a novel experimental set up based on heating a half soap bubble at its equator and cooling it at the pole. The displacement of these votices turns out to share similarities with that of hurricanes at large scales. This similarity and the properties of the environment of these vortices will be studied in detail. This study should allow us to propose a new scheme for prediciting hurricane corridors and link variations in their inetnsity to variations in their position. The study will first focus on a measurement of the rotation rate of these vortices and its correlations to variations in vortex position. At the same time numerical simulations of a situation similar to the experiments will be carried out by studying numerically thermal convection on a half sphere. In a second phase, the experimental set up will be subjected to rotation so as the effects of a Coriolis force can be introduced and their influence on the vortex trajectory and intensity studied systematically. In parallel, we will carry out a detailed study of the thermal convection in this half bubble both experimentally and numerically so as the environment in which the vortices live and move can be fully characterized. Much of this study will focus on the properties of turbulent convection in this novel setting without walls. We hope to bring new insights into the statistics of the temperature field for example and for which few if any measurements exist for its spatial fluctuations.

Pesticides are of limited use against bacterial diseases in crops due to a lack of effective and non-toxic molecules. Thus, genetic selection of resistant crops remains the most effective approach to control bacterial pathogens. Resistance breeding requires a conceptual jump to efficiently design significant and durable resistance to a large variety of pathogens in a large number of crops simultaneously. The CROpTAL project aims at identifying plant susceptibility hubs in major crops (cereals, citrus, legumes and brassicaceae) targeted by Xanthomonas virulence-promoting TAL (Transcription Activator-Like) type III effectors. These conserved susceptibility targets could then be used for marker-assisted breeding of loss-of-susceptibility by selection of inactive variants of those hubs. These results will contribute to the development of durable resistance to a broad range of bacterial pathogens in the selected crops.

Tropical cyclones are a major threat for many countries. They generate strong winds and deadly floods that damage buildings and infrastructure and severely disrupt civil and military organization. A precise forecast of the trajectory and intensity of tropical cyclones makes it possible to take the necessary measures to protect people and property while avoiding false alarms. The quality of the forecasts, however, depends largely on the quality of the observations. For the moment, only airborne measurements provide accurate in situ observations for the initialization of tropical cyclone prediction models. For this reason, the United States Air Force (USAF) and the National Oceanic and Atmospheric Administration (NOAA) have been deploying considerable resources for the observation of cyclones in the North Atlantic and East Pacific for several decades. These airborne measurements, carried out quite systematically by the USA and sporadically by Taiwan, are however exceptions worldwide. No airborne measurements are made in the South Indian Ocean, where the island of La Reunion is however regularly exposed to cyclones. Most of the real-time information collected by the Regional Specialized Meteorological Centers (RSMCs) therefore comes from satellite observations. These observations are irreplaceable, but they are sometimes inaccurate and are also too sporadic (a measurement every 12 hours for polar satellite instruments). In particular, the central pressure is a fundamental parameter for estimating the intensity of a cyclone, but satellite remote sensing approaches to assess the central pressure of cyclones are highly indirect and lack precision. Aeroclippers are balloons connected by a guide rope to the surface of the ocean. They evolve in the atmospheric surface layer, typically at a height of 30 to 50 meters. These balloons are carried away horizontally toward the eye of cyclones and then remain captured. The Aeroclipper is currently the only vector capable of giving an in situ measurement of the surface wind as it passes through the eyewall, then to provide continuous and real time measurements of the surface pressure in the eye until the cyclone dissipates. This balloon thus provides a unique possibility: (i) to follow the position and intensity of the cyclones; (ii) to improve the forecast of cyclones by assimilating the evolution of the central pressure; (iii) to evaluate and improve satellite approaches; and (iv) to correct possible biases in historical databases and thus to better detect a possible trend of the cyclonic characteristics during the last decades. The unique measurements given by Aeroclippers should also help improve our knowledge of cyclones. This is necessary to better predict the evolution of their characteristics in a warmer climate, in particular their poleward migration and their interaction with mid-latitude storms. Two Aeroclippers were already captured in Cyclone Dora in the Indian Ocean in 2007. After an interruption, developments resumed in 2015 with technical and financial support from the French center for space studies (CNES, Centre National d’Études Spatiales). Due to lack of human and funding resources, CNES must now suspend this development for an indefinite period of time (several years). The Aeroclipper system is however perfectly mature and it is not justified to postpone the first campaigns. The aim of this proposal is to validate the entire Aéroclipper system by conducting a test campaigns in 2020 and in 2021 with a new mechanical system and a new gondola currently under development at the Laboratoire de Météorologie Dynamique (LMD).

Protein-carbohydrate (PC) interactions play a key role in various biological processes. In particular, PC interactions govern infected erythrocyte (IE) adhesion on placental cells during placental malaria (PM) leading to severe pathological conditions. Experimental description of PC interfaces remains very challenging. The main goal of SugarPred is the development of structure- and sequence-based carbohydrate binding site prediction tools through implementation of the most recent machine learning approaches on the basis of the available structural data. We will apply the developed tools to VAR2CSA, the protein responsible for IE adhesion during PM, and will verify our predictions in direct experiment. This interdisciplinary approach will allow identification of VAR2CSA sugar-binding residues, and thus fill an important knowledge gap currently limiting the improvement of PM vaccines. A set of machine learning tools for the carbohydrate binding site prediction will be made available to the scientific community.