JOHN D. BREDEHOEFT retired in 1994 as deputy assistant chief research hydrologist at the Water Resources Division of the U.S. Geological Survey after 32 years of service. He now runs his own consulting firm, the HYDRODYNAMICS Group. At the USGS, he engaged in both research and high-level management. He managed the entire USGS water research activities for five years in the 1970s, and was the regional manager for all USGS water activities (regional hydrologist) in eight western states for four years in the early 1980s. He received his B.S.E. from Princeton University and his M.S. and Ph.D. in geology from the University of Illinois. He is a member of the National Academy of Engineering and the Russian Academy of Natural Sciences.
GEORGE P. DASTON is currently the principal research scientist in developmental and reproductive toxicology at the Miami Valley Laboratory of the Procter & Gamble Company in Ohio. Concurrently, he is an adjunct associate professor of pediatrics at the Children's Hospital Research Foundation at the University of Cincinnati. His research interests are developmental biology; teratology and toxicology, especially mechanisms of normal and abnormal development; nutrient-toxicant interactions; in vitro alternatives in teratology and toxicology; functional teratology; fluid balance in development; and risk assessment. He received his B.S. and Ph.D. in developmental biology and teratology from the University of Miami.
KENNETH L. DEMERJIAN is director of the Atmospheric Sciences Research Center and professor of atmospheric science at the State University of New York at Albany. His research interests include the chemistry and mechanistic processes of clean and polluted troposphere; kinetic and mechanistic pathway studies of atmospheric species; computer models for simulating air quality and atmospheric processes; and instrumentation development for the measurement of trace atmospheric constituents. He holds a B.S. from Northeastern University and an M.S. and a Ph.D. in physical chemistry from Ohio State University.
NINA V. FEDOROFF is the Willaman Professor of Life Sciences and director of the Biotechnology Institute at Pennsylvania State University. Dr. Fedoroff's research areas are plant transposable elements, epigenetic mechanisms, and plant development. She holds a B.S. in biology and chemistry from Syracuse University and a Ph.D. in molecular biology from Rockefeller University. She has been a member of the National Academy of Sciences since 1990.
ROLF HARTUNG is professor of environmental toxicology at the University of Michigan in Ann Arbor. His research interests include effects of polluting oils on waterfowl; toxicity of aminoethanols; coactions between chlorinated hydrocarbon.