<!--intro-->President Clinton today honored twelve renowned American scientists and engineers by naming them to receive the National Medal of Science. In announcing the year 2000 Medal of Science honorees, the president paid tribute to a diverse group of researchers who set new directions in social policy, neuroscience, biology, chemistry, bioengineering, mathematics, physics, and earth and environmental sciences. The medals will be presented at an awards dinner scheduled for December 1 in Washington, D.C.<!--/intro--> "These exceptional scientists and engineers have transformed our world and enhanced our daily lives," Clinton said. "Their imagination and ingenuity will continue to inspire future generations of American scientists to remain at the cutting edge of scientific discovery and technological innovation." Ten of the twelve science medalists this year received NSF support for portions of their academic careers or research work. The group honored today includes a Nobel Prize winner from the 1950s and another from the 1990s. Willis E. Lamb, a University of Arizona regents professor, received a 1955 Nobel Prize in Physics for his experimental work in hydrogen. His revelation of a quantum effect that became known as the "Lamb Shift" helped to create the new field of quantum electrodynamics, a key aspect of modern elementary particle physics. Four decades later, Gary Becker of the University of Chicago, received the 1992 Nobel Prize in Economics for his work in describing the role of social forces that shape individual economic behavior. He is well known for studies that led to new economic analyses of racial discrimination. The methods employed are still used to detect discrimination, such as recent studies on practices in mortgage lending. "We invest in people whose creative thinking leads to the discoveries that create new bodies of knowledge for the benefit and well-being of the American people," National Science Foundation (NSF) director Rita Colwell said. "The nation can be very proud of the extraordinary contributions these 12 stellar researchers and educators have made to their fields, their students, their colleagues and to the public." Medals of Science in biological sciences will go to: Nancy Andreasen of the University of Iowa; Peter H. Raven, director of the Missouri Botanical Garden and professor of botany at Washington University in St. Louis; and Carl R. Woese, professor of microbiology at the University of Illinois, Urbana-Champaign. Andreasen is known for her discovery of the relationship between manic-depressive illness and creativity. She was also one of the first scientists to demonstrate brain abnormalities in people with schizophrenia and mood disorders. Raven, a preeminent scientist in plant systematics and evolution, has published 550 books and papers. He introduced, with his colleagues, the concept of coevolution, which helped refocus much subsequent evolutionary research based on the co-adaptation between plants and animals. And he has directed the Missouri Botanical Garden into a position of national prominence as a center for the study of plant diversity. Woese's work in proposing the notion that there are three primary evolutionary domains into which all living things may be classified led to a quantitative map, or universal tree of life, by which the diversity of all life can be assessed. For chemistry, John D. Baldeschwieler of CalTech and Ralph F. Hirschmann of the University of Pennsylvania are receiving the science medal. Baldeschwieler's work in molecular assemblies led to practical pharmaceutical products and instrumentation. He developed Ion Cyclotron Resonance Spectroscopy, an important tool for chemical and biochemical analysis that led to a new scientific field providing unique ways to study molecular structure and reactivity. Hirschmann's research while at Merck & Co., Inc., led to a host of new medicines, such as the anti-parasitic drug Ivermec that is helping to eradicate river blindness in the Third World. His work also led to drugs that treat hypertension, congestive heart failure and severe infection. Research bioengineer Yuan-Cheng Fung of the University of California at San Diego made major contributions to the field of aeroelasticity, which formed the defining ideas in an important area of aerospace engineering. In the late 1960s, he conducted pioneering research in biomechanics by applying his knowledge of mechanics to the study of biological tissues. Results of his work are helping to solve important biomedical problems. Mathematicians John Griggs Thompson of the University of Florida and Karen K. Uhlenbeck of the University of Texas Austin are receiving medals for their theoretical work. Thompson is considered a world leader in group theory, the most fundamental of all algebraic structures. Arising from studies of symmetry in nature, the first application of group theory was used in solving polynomial equations. In 1970, Thompson was awarded mathematics' top international prize, the Fields Medal, for his work in classifying all of the finite simple groups. Uhlenbeck stands out as one of the founders of geometry based on analytical methods and is a leader in her field as a mentor for women and minorities in mathematics education. In physics, Jeremiah P. Ostriker of Princeton University is receiving a medal for contributions that advanced the understanding of the dynamics of galaxies and star clusters, including the existence of large quantities of dark matter. Medalist Gilbert F. White, a professor of geography at the University of Colorado, has had an impact on the nation's public policy for over five decades regarding uses of floodplains and non-structural approaches to reduce damage from flooding and other natural hazards. NSF administers the Medals of Science for the White House.