High Quality Content by WIKIPEDIA articles! Bernard Leonard Cohen (June 14, 1924 – March 17, 2012) was born in Pittsburgh, and was Professor Emeritus of Physics at the University of Pittsburgh. Professor Cohen was a staunch opponent to the so-called Linear no-threshold model (LNT) which postulates there exists no safe threshold for radiation exposure. His views, what was in the 1980s and 1990s considered a self-marginalizing posture had gained within 20 years support from a strong minority. He died in March 2012.