First Author:   Tito Moreira Catholic University tito@pos.ucb.br   SGAN 916, Módulo B, Asa Norte Brasília, 70.790-160, Brazil   (61) 340-5550(Phone) (61) 340-5550(Fax) Second Author: Adolfo Sachsida Catholic University Sachsida@pos.ucb.br   SGAN 916, Módulo B, Asa Norte Brasília, 70.790-160, Brazil   (61) 340-5550(Phone)   Third Author: Loureiro Paulo Catholic University loureiro@pos.ucb.br   SGAN 916, Módulo B, Asa Norte Brasília, 70.790-160, Brazil   (61) 340-5550(Phone)