Luiz carlos de santana Ribeiro Federal University of Sergipe   Rodovia Engenheiro Edilson Távora, 6800 Casa 709 Barra dos Coqueiros, SE 49142442 Brasil   ribeiro.luiz84@gmail.com   www.leaderufs.com.br           JEL Areas: R1 : General Regional Economics (includes Regional Data) C0 : Mathematical and Quantitative Methods: General