First Author:   Edgar J Sanchez Carrera University of Siena sanchezcarre@unisi.it   via Valdimontone 1 Siena, 53100, Italy   +39 0577 235058(Phone) +39 0577 235058(Fax) Second Author: W. Adrian Risso University of Siena risso@unisi.it         Third Author: Juan Gabriel Brida Free University of Bolzano, Italy. JuanGabriel.Brida@unibz.it     +39 0471 013492(Phone) +39 0471 013 009(Fax)