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PRACTICAL APPLICATIONSAt Rensselaer, applied mathematics work on problems with realworld solutionsby Patrick Kurp 

David Isaacson, professor of mathematics at Rensselaer, built his first electrocardiograph while still a high school student in New York City. He did it in the wake of Sputnik I, when bright, patriotic American kids were passionate about science, especially space exploration. Isaacson had already designed and constructed a centrifuge, scaled for the body of a mouse, and now he wanted to monitor the effects of increased Gforces on rodent physiology. “I wanted to measure the mouse’s heart rate. The problem was, the electrocardiograph worked on people, not on a mouse. I didn’t know there was such a difference in their bodies,” Isaacson says. Flash forward more than a decade. It’s 1975, and Isaacson is a graduate student in mathematics at New York University. His father, a mathematician at NYU, has suffered a heart attack. “I saw him in the hospital all wired up, and I got to thinking about electrocardiographs again, how you could measure the voltage of the body’s surface. I thought that these machines could be improved and I just kept on thinking about it,” says Isaacson, whose father survived his heart attack and is still going strong almost a quartercentury later. Since coming to Rensselaer
in 1980, Isaacson has devoted much of his research to conductivity imaging—measuring
and

Photo
by Mark McCarty
Adding Value:
(clockwise from upper left) Ashwani Kapila, Isom Herron, David Isaacson
(white shirt), Donald Schwendeman, Mark Holmes, Margaret Cheney, and Thomas
Yu. So, what’s a mathematician doing messing around with diagnostic medical hardware? Don’t mathematicians ponder nice clean abstractions and leave the messiness of the real world alone? “Well, that’s the stereotype, but it’s not really accurate. The math department at Rensselaer is almost entirely applied mathematics. We work on problems that have practical value, even though there’s also an aesthetic component. The math that survives tends to be useful math,” Isaacson says. Continued on next page 