Institution: | a Department of Mathematical and Statistical Sciences, Applied Mathematics Institute, University of Alberta, Edmonton, Alta. Canada T6G 2G1 b Institute for Geophysical Research, University of Alberta, Edmonton, Alta. Canada T6G 2G1 c Department of Mathematics, Physics and Computer Science, Ryerson Polytechnic University, Toronto, Ont., Canada M5B 2K3 d Department of Applied Mathematics, University of Waterloo, Waterloo, Ont., Canada N2L 3G1 |