Max-Planck-Institute for Dynamics and Self-Organization, Göttingen, Germany. reichl@nld.ds.mpg.de|Max-Planck-Institute for Dynamics and Self-Organization, Göttingen, Germany. reichl@nld.ds.mpg.de|Max-Planck-Institute for Dynamics and Self-Organization, Göttingen, Germany. reichl@nld.ds.mpg.de|Max-Planck-Institute for Dynamics and Self-Organization, Göttingen, Germany. reichl@nld.ds.mpg.de|Max-Planck-Institute for Dynamics and Self-Organization, Göttingen, Germany. reichl@nld.ds.mpg.de|Max-Planck-Institute for Dynamics and Self-Organization, Göttingen, Germany. reichl@nld.ds.mpg.de