Weihnachten customs held upon returning from church leading to the gift giving vary across the German-speaking countries. One of the most common situations sees the returning children wait to enter into their (locked) living room until a little bell rings. This bell marks the departure of the one delivering gifts. In the more Catholic regions - primarily South Germany and Switzerland - this is considered the Christ Child ("Christkind"), while those in North Germany commonly consider it to be the "Weihnachtsmann" (Saint Nicholas or Santa Claus) who is exiting. The children then enter to see the decorated Weihnachtsbaum (Christmas tree), with
Rina Tannenbaum as those of the American Chemical Society, Wiley and Elsevier . For her work she has received many awards and was involved in a variety of professional activities. For example, she was a co-organizer of Symposium Y at the Spring 2001 Materials Research Society Meeting, was a plenary speaker at the Third International Conference on Polymer Behavior (ICPB3) in 2008, and delivered the WISE 10th Anniversary Distinguished Lecture at the University of Southern California in the Fall 2009 . Rina Tannenbaum Rina (Irena) Tannenbaum (born December 13, 1953) is an Israeli/American materials scientist and chemical engineer and presently Professor in