1. Tandon School of Engineering, New York University, New York, NY 11201, USA
2. Max Planck Institute for Dynamics and Self-Organization, Göttingen 37077, Germany
3. Laboratoire de Physique, ENS de Lyon and CNRS, Lyon 69007, France
4. Institute for Nonlinear Dynamics, University of Göttingen, Göttingen 37077, Germany