D.R. Bosanquet MRC/UCT Medical Imaging Research Unit Department of Human Biology University of Cape Town Observatory 7925 South Africa Email: [email protected] Tel: +27 84 661 1343 Fax: +27 21 448 7226 L.R. John MRC/UCT Medical Imaging Research Unit Department of Human Biology University of Cape Town Observatory 7925 South Africa Email: [email protected] Tel: +27 21 406 6548 Fax: +...