Philip Aston was in Baltimore, Maryland, during 6-9 November, for the 37th Annual Meeting of the American College of Toxicology which was held at the Baltimore Marriott Waterfront Hotel.  He gave an invited presentation entitled “Analysis of periodic physiological signals using the mathematics of chaos theory” as part of a Symposium organized by Dusty Sarazan (previously DSI) and Syril Pettit (HESI).