Address 3 Rue Michel-Ange 75794 Paris Cedex 16 France TROPECOS members from CNRS Gwenaël ABRILCNRS research director (Paris), Visiting professor, Universidade Federal Fluminense (Niterói, Brazil) Axel FELBACQAssistant engineer, CNRS Pierre GAUDINAssistant engineer, CNRS (Angers) Roberto GRILLIResearch scientist, CNRS Cornelia RUMPELCNRS research director (Paris) Sabine SCHMIDTResearch director, CNRS (Bordeaux) Vincent VANTREPOTTEResearch Scientist, CNRS - IRD (Wimereux) and visiting professor, Federal University of Permambouco (Brazil)