1. Heat and Mass Transfer Technological Center, Technical University of Catalonia, C/Colom 11, 08222 Terrassa, Spain
2. Keldysh Institute of Applied Mathematics, 4A, Miusskaya Sq., Moscow 125047, Russia
3. Johann Bernoulli Institute for Mathematics and Computer Science, University of Groningen, P.O. Box 407, 9700 AK Groningen, The Netherlands