President Bush presented science and technology achievement medals on Monday to 15 laureates who have done work that has revolutionized organ transplants, led to development of global positioning systems and helped feed millions around the world.

"The spirit of discovery is one of our national strengths," Bush said before handing out the 2004 National Medals of Science and Technology in the White House's East Room. "Our greatest resource has always been the educated, hardworking, ambitious people who call this country their home.

"From Thomas Edison's light bulb to Robert Ledley's CAT scan machine, most of America's revolutionary inventions began with men and women with a vision to see beyond what is and the desire to pursue what might be."

Established by Congress in 1959, the medal of science award is administered by the National Science Foundation. The ceremony brought to 425 the total number of medal of science recipients.

The medal of technology, established by Congress in 1980, is administered by the Commerce Department. So far, 166 of these technology medals have been awarded.

Medal recipients in science:

—Kenneth J. Arrow, Stanford University; Stanford, Calif., for his contributions in the field of economics.

—Norman E. Borlaug, Texas A&M University; College Station, Texas, for breeding semi-dwarf, disease-resistant high-yield wheat and instructing farmers in its cultivation to help ease starvation.

—Robert N. Clayton, The University of Chicago, for his contributions to geochemistry and cosmochemistry that provided insight into the evolution of the solar system.

—Edwin N. Lightfoot, University of Wisconsin, for research in how the body controls insulin levels and oxygenates blood.

—Stephen J. Lippard, Massachusetts Institute of Technology, for research in bioinorganic chemistry, including the interaction of metal compounds with DNA.

—Phillip A. Sharp, Massachusetts Institute of Technology, for his genetic research, including his role in discovering the discontinuous nature of genetic information in split genes.

—Thomas E. Starzl, University of Pittsburgh School of Medicine, for his work in liver transplantation and his discoveries in immunosuppressive medication that advanced the field of organ transplantation.

—Dennis P. Sullivan, City University of New York Graduate Center and State University of New York at Stony Brook, for his work in mathematics, including the creation of entirely new fields of mathematics, and uncovering unexpected connections between seemingly unrelated fields.

Medal recipients in technology:

—Ralph H. Baer, engineering consultant; Manchester, N.H., for his work in developing and commercializing interactive video games, which spawned related uses and mega-industries in both the entertainment and education fields.

—Roger L. Easton, founder of RoBarCo, a private consulting firm in Canaan, N.H., for his achievements in spacecraft tracking, navigation, and timing technology that led to the development of the NAVSTAR-Global Positioning System.

—Gen-Probe Inc. of San Diego, Calif., for the development and commercialization of new blood-testing technologies and systems for the direct detection of viral infections, including West Nile virus, HIV-1 and Hepatitis C virus in plasma of human blood and organ donors prior to transfusion. The award was accepted by Henry L. Nordhoff, president, chairman and chief executive officer.

—IBM Microelectronics Division of Armonk, N.Y., for innovation in semiconductor technology that has enabled explosive growth in the information technology and consumer electronics industries through the development of smaller, more powerful microelectronic devices. The award was accepted by Nicholas M. Donofrio, executive vice president of innovation and technology.

—Industrial Light and Magic of San Francisco, Calif., for 30 years of innovation in visual effects technology for the motion picture industry. Chrissie England, president, and George Lucas, founder, accepted the award.

—Motorola Inc. of Schaumburg, Ill., for work in mobile communications, and for the development of innovations that allow people to connect with their world. The award was received by Padmasree Warrior, executive vice president and chief technology officer.

—PACCAR Inc. of Bellevue, Wash., for pioneering work in the development and commercialization of aerodynamic, lightweight trucks that have dramatically reduced fuel consumption and increased the productivity of U.S. freight transportation. The award was accepted by Mark C. Pigott, chairman and chief executive officer.