Three of the 13 awards this year are going to astronomers, including the academy's highest honor--the Public Welfare Medal--which is being given to Carl E. Sagan, 59, David Duncan Professor of Astronomy and Space Sciences at Cornell University, Ithaca, N.Y.
Every year, NAS presents this medal (the only award without an accompanying cash prize) to an individual who has made extraordinary use of science for the public good.
Perhaps best known as the creator and producer of the popular science television series Cosmos (a public TV offering that has won both the Emmy and Peabody awards), Sagan is being honored for "communicating the wonder and importance of science."
"His ability to capture the imagination of millions and to explain difficult concepts in understandable terms is a magnificent achievement," said Peter H. Raven, NAS home secretary and the chairman of the 1994 selection committee, in a statement.
"This award is given for outstanding contributions to the public, not for individual scientific achievements," says Thomas Gold, a professor, emeritus, of astronomy at Cornell University and himself a full member of NAS. "He [Sagan] is absolutely terrific at what he does--bringing science to the public and keeping their interest in it alive." (For more information on Sagan, see story on page 7.)
Unlike the recipient of the Public Service Medal, the other two astronomers were awarded prizes that always go to scientists in that field, though not on an annual basis. Donald E. Brownlee, 50, a professor of astronomy at the University of Washington, Seattle, will be receiving the J. Lawrence Smith Medal (and $20,000 for investigations of meteoric bodies), for his studies on interplanetary dust particles, which are an important source of information about both asteroids and comets.
"They offer a different window into the early solar system," says Brownlee, "because the original properties of the materials--from the time that our solar system first came into being 4.6 billion years ago--are still preserved." His group was the first to collect this material from the outer layers of the Earth's atmosphere, using high-altitude balloons and U2 airplanes. He has received many honors; for example, he is the namesake of the Asteroid 3259 Brownlee, named in 1991.
The James Craig Watson Medal with a cash award of $15,000 is going to Yasuo Tanaka, the deputy director general and planning and coordination director of the Institute of Space and Aeronautical Sciences in Kanagawa, Japan. Tanaka was named for his contributions to X-ray astronomy and for his role in establishing the U.S.-Japanese collaboration in the ASCA mission. ASCA is an X-ray satellite built by the Japanese and launched by the Americans.
Says Virginia Trimble, a professor of physics at the University of California, Irvine, "It is producing fantastically good results about clusters of galaxies and other things in space."
At 59, Carl Sagan, recipient of the Public Welfare Medal from the National Academy of Sciences this year, continues to play an important role as a communicator of science, wearing different hats--writer, teacher/lecturer, and laboratory scientist--to do so.
The author, coauthor, or editor of more than 20 books written for lay audiences, he is a prolific writer with more than 600 publications--including scientific papers as well as popular articles--to his credit. He is a regular contributor to the magazine Parade, a Sunday supplement to many newspapers across the United States.
"I take [writing this column] very seriously, as it is an important vehicle to keep the public informed about science," says Sagan. "The magazine goes out to several million people and is the most widely read publication of its kind in the United States, if not the world."
In 1978 Sagan received the Pulitzer Prize for his Dragons of Eden (New York, Random House Inc., 1977). His most recent book, cowritten with his wife, Ann Druyan, is Shadows of Forgotten Ancestors: A Search for Who We Are, (Random House, 1992). He has just finished a new book that is scheduled for publication later this year, called Pale Blue Dots: A Vision of the Human Future in Space. The title, says Sagan, is based on pictures of Earth taken from beyond Neptune, by the spacecraft Voyager.
Echoing his perennial and well-known pronouncements characterizing Earth's inhabitants as voyagers on a vast sea of time, Sagan--who played important roles in the Neptune and other outer-space expeditions--says about the photographs and his new book: "It gives an idea of how small and insignificant the Earth seems in comparison to the rest of the universe."
Sagan received all of his higher education at the University of Chicago, graduating with a master's degree in physics in 1956 and a Ph.D. in astronomy and astrophysics in 1960. Since 1968 he has been at Cornell University, where, he continues to teach both graduate and undergraduate courses in astronomy, space sciences, and critical thinking. He is an active scientist as well; research interests over the years have included topics such as the greenhouse effect on Venus, seasonal changes on Mars, the long-term environmental consequences of nuclear war, and the origin of life on Earth. In addition, he is the director of Cornell University's Laboratory for Planetary Studies, a facility that Cornell President Frank H.T. Rhodes has called "universe-class--due in large part to Carl's contributions."
A second discipline that features prominently among this year's awards is neuroscience; in addition to the NAS Award in the Neurosciences and the annual Troland Research Awards for quantitative and physiological studies in psychology, the 1994 NAS Award for Scientific Reviewing honors this field. Thomas Jessell, 43, of the Columbia University College of Physicians and Surgeons in New York, has been cited for "bridging the fields of developmental neurobiology and developmental biology," by writing and editing reviews. Recent important review papers by Jessell include: "Synaptic transmission: a bidirectional and self-modifiable form of cell-cell communication," Cell (v72) / Neuron Review Supplement, 10:1-30, 1993; and "Diffusible factors in vertebrate embryonic induction," Cell, 68:257-70, 1992.
The two Troland Research Awards, each a prize of $35,000, are being given to Donald D. Hoffman, a professor of cognitive science at the University of California, Irvine, and David D. Lavond of the University of Southern California in Los Angeles, in the quantitative and physiological research categories, respectively.
Hoffman, 38, cited by the academy for his research in the area of human visual perception, has developed mathematical and computational models for the manner in which humans convert the two-dimensional images from their retinas to three-dimensional pictures.
"We [the viewers] are computing depth from flat images," explains Hoffman. According to his model, "The three-dimensional picture we see is actually a theory: the best inference based on data--2-D images--and assumptions. The visual system is very much like a scientist." While he has built specific models for various visual abilities, such as deducing depth from motion, shape from shading, and stereo vision, Hoffman's main contribution to the field has been to develop a general framework for perceptual inference.
"Our claim is that there is a common, formal structure underlying the theories of each ability, limited not only to visual capacities but also to other perceptions, such as touch and localization by hearing," he says. These hypotheses are detailed by Hoffman and his colleagues, mathematicians Bruce Bennett at UC- Irvine and Chetan Prakash at California State University, San Bernardino, in two major publications: a book titled Observer Mechanics: A Formal Theory of Perception (New York, Academic Press, 1989) and an article, "Unity of perception" (Cognition, 38:295-334, 1991).
Lavond, 41, is among the first scientists to have used a new reversible cooling technique in the study of structure-function relationships in the brains of mammals.
"Until now, the only way to localize functions was to create lesions in the brain that resulted in permanent damage," says Lavond. "There was no way to reverse the lesion and see if a function could be restored. Using this new technique, we can prove the involvement of any given region in a specific activity."
The method introduces a probe into the desired location and temporarily inactivates the region by cooling the cells. Recording electrodes attached to the probe keep tabs on the activity of the cells. When the coolant is removed, the cells are restored to their normal temperatures and activity. Lavond has applied this technique to localize certain memory and learning behaviors to two specific regions of the brain.
"The technique adds another dimension to the study," explains Lavond. "Because of the recording devices we attach to the cooling probe, we are able to record the brain activity of both regions at the same time--thus determining the type of participation of each region in any given activity."
Walle J.H. Nauta, an emeritus professor of brain and cognitive sciences at the Massachusetts Institute of Technology in Cambridge, had been named the recipient of the neurosciences award, a gold medal with a cash prize of $15,000. After the announcement was made, however, Nauta, who was 77, died of a blood infection on March 24, having been hospitalized for a few days in Cambridge, Mass. The award will be given posthumously.
Sharing the NAS Award in Molecular Biology, which recognizes recent notable discoveries by young scientists, are Gerald F. Joyce, 37, an associate professor at the Scripps Research Institute, La Jolla, Calif., and Jack W. Szostak, 41, a professor of genetics at Harvard Medical School, Boston. Working independently but simultaneously, both awardees have produced ribozymes--RNA molecules with specific enzymatic or catalytic properties--using principles of natural selection rather than synthetic processes.
"We are observing Darwinian evolution in the test tube and making new molecules that do not, as far as we know, exist in nature," says Joyce, whose laboratory has produced populations of ribozymes that cleave DNA molecules and some that use calcium ions to cleave RNA molecules instead of the normally used magnesium ions.
The method involves introducing very large populations--10 to 100 trillion RNA molecules--in a test tube to a target chemical reaction. "We rig the system so that any RNA molecule acquiring the desired cleavage property is tagged chemically," explains Joyce. These tagged molecules are picked up and amplified and subjected to mutations; progeny RNA molecules are cycled through the selection-amplification-mutation steps several times and at each level, the molecules' function, efficiency, and structure are assessed, allowing the scientists to follow the evolution of the enzymes in a stepwise fashion.
Szostak's laboratory has produced ribozymes that can join small pieces of RNA together, which he describes as "something between a polymerase and a ligase."
The NAS Award for Initiatives in Research, awarded annually to young scientists to encourage investigations that will likely lead to new capabilities for the benefit of humanity, goes to Joanne Chory, 38, at the plant biology laboratory of the Salk Institute for Biological Studies, San Diego.
Chory is receiving the $15,000 prize for her research in uncovering the genetic and molecular events that determine how seedlings make developmental decisions in response to light.
"We are studying a very fundamental problem that could eventually lead to practical applications in agriculture," she says.
The academy has also selected six other noteworthy individuals from a number of specialties to be honored at the April 25 meeting:
Botanist Elisabeth Gantt, 59, of the University of Maryland, College Park, is being awarded the Gilbert Morgan Smith Medal and a cash prize of $15,000 for published research on marine or freshwater algae. Gantt discovered a new type of light-harvesting complex called phycobilisomes, unique to red and blue-green algae.
The Jessie Stevenson Kovalenko Medal and $25,000 go to Donald Metcalf of the Walter and Eliza Hall Institute of Medical Research in Melbourne, Australia, for his work on the clinical applications of blood-cell growth factors. Recently, Metcalf, 65, also received the prestigious Albert Lasker Clinical Medical Research Award (B. Spector, The Scientist, Oct. 18, 1993, page 1) and Columbia University's Louisa Gross Horwitz Prize (N. Sankaran, The Scientist, Feb. 7, 1994, page 23) Koji Nakanishi, 73, Centennial Professor in the department of chemistry at Columbia University, is receiving the NAS Award in Chemical Sciences, a bronze medal and $10,000 in cash. Nakanishi does research on bioactive compounds produced by plants and animals, and has isolated and determined structures of a vast array of these compounds. The academy has also cited him for his contributions in vision research, particularly in finding the role of the compound retinal.
The John J. Carty Award for the Advancement of Science, for noteworthy and distinguished accomplishments in a subject within the academy's charter, goes to Marina Ratner, 55, a professor of mathematics at the University of California, Berkeley. She is receiving the $25,000 prize for providing proofs for a group of mathematical results called the Ragunathan conjectures. The G.K. Warren Prize, an award of $6,000, is going to Claudio Vito-Finzi, a professor of geology at University College, London, England, for his field investigations and resulting contributions to fluvial morphology.