Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, New Mexico, USA.|Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, New Mexico, USA.|Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, New Mexico, USA.|Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, New Mexico, USA.|Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, New Mexico, USA.