1. Department of Mathematics, MIT, Cambridge, Massachusetts 02139, USA
2. Matière et Sytèmes Complexes, CNRS UMR 7057, Université Paris Diderot, Sorbonne Paris Cité, 75013 Paris, France
3. Microfluidics Lab, Department of Mechanical and Aerospace Engineering, University of Liege, Allée de la Découverte 9, 4000 Liège, Belgium
4. Department of Mathematical Sciences, University of Bath, Bath BA2 7AY, United Kingdom
5. National Institute for Pure and Applied Mathematics (IMPA), Est. D. Castorina 110, Rio de Janeiro, RJ 22460-320, Brazil