David Hunter Hubel FRS (February 27, 1926 – September 22, 2013) was a Canadian American neurophysiologist noted for his studies of the structure and function of the visual cortex.He was co-recipient with Torsten Wiesel of the 1981 Nobel Prize in Physiology or Medicine (shared with Roger W. Sperry), for their discoveries concerning information processing in the visual system.

David Lawrence Sackett OC FRSC (November 17, 1934 – May 13, 2015) was an American-Canadian physician and a pioneer in evidence-based medicine. He is known as one of the fathers of Evidence-Based Medicine.He founded the first department of clinical epidemiology in Canada at McMaster University, and the Oxford Centre for Evidence-Based Medicine. He is well known …