1. Department
of Biological Sciences, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
2. Department
of Computer Science, Aberystwyth University, Ceredigion SY23 3FL, Wales, U.K.
3. Center
of Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
4. Department
of Chemistry, College of the Holy Cross, Worcester, Massachusetts 01610, United States