First Author:   Marcelo Bourguignon Universidade Federal do Rio Grande do Norte m.p.bourguignon@gmail.com         Second Author: Tito Lívio Universidade Federal do Piauí titolivio@ufpi.edu.br         Third Author: Naushad Mamode Khan University of Mauritius n.mamodekhan@uom.ac.mu         Fourth Author: Hassan S. Bakouch Tanta University hnbakouch@yahoo.com