First Author:   Fábio A. R. Gomes Department of Economics - FEA-RP, University of São Paulo fabiogomes@fearp.usp.br   Av. Bandeirantes 3900, Monte Alegre Ribeirão Preto, 14040-905, Brazil   55 (16) 3602-3839(Phone) 55 (16) 3602-3839(Fax) Second Author: Gian Paulo Soave Postdoctoral Research Associate - FEA-RP, University of São Paulo gianps@usp.br   Ribeirão Preto, 14040-905, Brazil