[1] Inst Natl Rech Sci, Ctr Energie Mat Telecommun, Varennes, PQ J3X 1S2, Canada
[2] Univ Ottawa, Dept Phys, Ottawa, ON K1N 6N5, Canada
[3] Univ Munich, Dept Heart Surg, D-81377 Munich, Germany
[4] Univ Oxford, Botnar Res Ctr, NDORMS, Oxford OX1 2JD, England