1. Theoretical Biology and Biophysics Group (T-6), Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 USA.
2. Information Sciences Group (CCS-3), Computer, Computational and Statistical Sciences Division, Los Alamos National Laboratory, Los Alamos, NM 87545 USA.
3. Department of Mathematics, The University of Texas at Arlington, Arlington, TX 76019 USA.
4. Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, NM 87545 USA.