1. Institute for Nonlinear Science, University of California San Diego, La Jolla 92093-0402, U.S.A.,
2. Instituto de Física, Universidade de São Paulo, São Paulo 05508-090, Brazil,
3. Institute for Nonlinear Science, University of California San Diego, La Jolla 92093-0402, U.S.A., and Departamento de Ingeniería Informática, Universidad Autónoma de Madrid, Madrid, Spain,
4. Instituto de Física, Universidade de São Paulo, São Paulo 05508-090, Brazil, and Institute for Nonlinear Science, University of California San Diego, La Jolla 92093-0402, U.S.A.,