Max Planck Institute for Dynamics and Self-Organization (MPIDS), Göttingen, Germany , Institute for Nonlinear Dynamics, Department of Physics, University of Göttingen, Göttingen, Germany.|Max Planck Institute for Dynamics and Self-Organization (MPIDS), Göttingen, Germany , Institute for Nonlinear Dynamics, Department of Physics, University of Göttingen, Göttingen, Germany.