Two members of Cornell University's faculty – one from Lebanon, the other from South Africa, one studying plant reproduction, the other probing black holes – have been elected to the National Academy of Sciences (NAS). They are June B. Nasrallah, professor of plant biology, and Saul A. Teukolsky, the Hans A. Bethe Professor in Physics and Astrophysics.

Their election brings to 48 the number of faculty members from Cornell's Ithaca campus and the Weill Cornell Medical College in the NAS. Election to the academy, a private organization dedicated to the furtherance of science and its use for the general welfare, is considered one of the highest honors for a U.S. scientist or engineer.

Robert Richardson, vice provost for research at Cornell, expressed his satisfaction at the election of the two researchers. Nasrallah and her co-workers, he said, "combined methods of cell biology and molecular genetics to explain why some plants do not self-pollinate. She identified the genes whose products, synthesized by the female and male parts of the flower, interact to cause rejection of self-pollen. Her accomplishment has great fundamental and practical significance."

Teukolsky, Richardson said, "has made significant contributions to relativistic astrophysics, including the Teukolsky Formalism for black hole perturbations. He developed important numerical techniques for understanding star clusters, black holes, neutron stars and their collisions or mergers. With [Stuart L.] Shapiro, he co-authored the textBlack Holes, White Dwarfs, and Neutron Stars: The Physics of Compact Objects, which has been the standard reference on the subject for 18 years."

Nasrallah and Teukolsky were among the 72 new members and 18 foreign associates from 11 countries elected to NAS membership in recognition of their distinguished and continuing achievements in original research. There are now 1,922 active members of the NAS.

Nasrallah, who was born in Lebanon, studies plant reproductive biology and signal transduction, and her research has helped to unlock some secrets of plant cell communication. The focus of her research is self-incompatibility, a process that prevents plant inbreeding and promotes out-crossing (fertilization from another plant) and variability. She and her husband, Mikhail Nasrallah, also a Cornell professor of plant biology, were among the first to identify a receptor-ligand system for plant cell-to-cell communication. In 1999, together with former postdoctoral researcher Christel Schopfer, they published a seminal paper in the journal Science that unveiled the gene that tells plants' stigma receptors which pollen to accept or reject.

Two years later the Nasrallahs and co-workers published more research in Science that could enable genetic engineers to short-circuit the reproductive process and switch a species' mating system from selfing (self-fertilization) to out-crossing.

Since 1997, Nasrallah has been a member and chair of Cornell's Plant Genomics Focus Group, and since 2001, she has been director of graduate studies for plant biology. She has served on the editorial board of the journal Sexual Plant Reproduction since 1988 and was associate editor of the journal Plant Physiology from 1995 to 1998.

Arriving at Cornell 1977 as a postdoctoral researcher in the Section of Genetics and Development, Nasrallah became a lecturer and research associate in 1981. She was named an assistant professor in 1985 and a full professor in 1997.

Nasrallah obtained her bachelor's degree from the American University of Beirut in 1971 and her doctorate from Cornell in 1977.

Teukolsky will be among the invited speakers at the national meeting of the American Astronomical Society (AAS) Division on Dynamical Astronomy May 4 to 7, being held this year at Cornell. He will discuss his long-term project to solve Einstein's equations of general relativity by computer. One of the ultimate goals of the project is to predict the gravitational wave form from coalescing black holes in binary orbit about each other.

Problems involving black holes are particularly challenging, says Teukolsky, who, at the AAS meeting, will describe the results of recent calculations of black hole collisions and relate the results to the current observational search for gravitational waves. It is expected that such events will be among the Þrst signals detected when the Laser Interferometer Gravitational Wave Observatory (LIGO) comes into operation within the next two years.

Teukolsky's recent research has spanned many other topics in relativistic astrophysics. He has worked on naked singularities in general relativity; the properties of rapidly rotating neutron stars, including possible observational signatures in pulsars; exploding neutron stars; relativistic stellar dynamics; and planets around pulsars.

Born in South Africa, Teukolsky graduated with honors degrees in mathematics and physics from the University of the Witwatersrand in 1970. He earned his doctorate in theoretical physics from the California Institute of Technology (Caltech) in 1973. After working as a research fellow at Caltech he joined the Cornell faculty as an assistant professor in physics and astronomy in 1974. He became a full professor in 1983 and was named to his current post in 1999. Also in 1999 he was named director of the Center for Radiophysics and Space Research, one of the two research centers of the Cornell astronomy department.

He spent last year as a consulting scientist, helping to organize the Einstein exhibit at the American Museum of Natural History in New York City, which has been drawing large crowds since its opening last November.