1. Department of Physics, North Dakota State University, Fargo, North Dakota 58105-5566, Faculty of Electrical Engineering, Tržaška 25, University of Ljubljana, 1000 Ljubljana, Slovenia, Faculty of Chemistry and Chemical Technology, University of Ljubljana, 1000 Ljubljana, Slovenia, Dipartimento di Matematica e Informatica, Universita 'di Trieste, 34100 Trieste, Italy, and University College of Health Studies, Poljanska 26a, University of Ljubljana, 1000 Ljubljana, Slovenia