First Author:   Pierre Cariou Euromed Management pierre.cariou@euromed-management.com   Euromed Management, 13288 Marseilles, BP921, France   +33(0)491 827 859(Phone) +33(0)491 827 859(Fax) Second Author: François-charles Wolff LEMNA, University of Nantes francois.wolff@univ-nantes.fr   Chemin de la Censive du Tertre, Chemin de la Censive du Tertre, 44322 Nantes, France   +33 (0)240 905 092(Phone) +33 (0)240 141 700(Fax) www.sc-eco.univ-nantes.fr/~fcwolff