During the week of 14-18 January 2008, SCL's Antun Balaz visited the Department of Physics of the University of Duisburg-Essen. This visit is a follow-up to the earlier visit, and represents a continuation of research collaboration of SCL's path integral group and Dr. Axel Pelster. Current topics include derivation of recursive relations for effective actions that improve the convergence of path integral Monte Carlo calculations, as well as application of N=1 approximation (one time slice) for path integrals for calculation of the critical temperature of the Bose-Einstein condensate of Rb atoms in anharmonic trap. Initial results will be presented during the poster session of the Dynamics and Statistical Physics Division at the 2008 Spring Conference of the German Physical Society.