Complex sentence: Dr. Dorn addressed the UN General Assembly in 1988 at the Second UN Special Session on Disarmament and, since 1983, he has served as the UN Representative of Science for Peace, a Canadian NGO.
Split into simpler sentences: Dr. Dorn addressed the UN General Assembly in 1988 at the Second UN Special Session on Disarmament. Since 1983, he has served as the UN Representative of Science for Peace, a Canadian NGO.