An internal voyage

Oliver Sacks, America's most famous neurologist, is conducting a tour of the human brain and nervous system in a mini-series broadcast every Tuesday on public television station KUTV, Ch. 7.

"Oliver Sacks: The Mind Traveler" offers a compassionate look at a variety of ailments and in doing so helps the viewer better understand the intricacies of the system. The first episode was broadcast Tuesday at 8 p.m., with the remaining three features scheduled for the same time on succeeding Tuesday evenings.

Sacks is the author of several popular nonfiction books, including "The Man Who Mistook His Wife for a Hat" and "Awakenings," which was made into a film of the same title starring Robin Williams.

Cheaper flights

A 30-inch "scramjet" engine that promises to lead to cheaper high-speed aircraft has been delivered to NASA's Langley Research Center in Hampton, VA. The engine was built by GASL Inc. of Ronkonkoma, N.Y., for a program called Hyper-X.

In the $170 million Hyper-X program, aerospace experts hope to demonstrate that "air-breathing" engines could be applied to aircraft flying at five times the speed of sound (Mach 5) and even to reusable space launchers that operate within the atmosphere. Presently, the fastest air-breathing engine on any American aircraft is that of the SR-71 spy plane, which can reach Mach 3.

Rockets carry their own propellants, including oxygen for combustion. An air-breathing vehicle burns oxygen scooped up from the atmosphere as it zooms along. Air-breathing hypersonic boosters thus could weigh much less per pound of thrust and be able to carry more payload per pound than do rockets.

Russians have used a booster rocket to show that air-breathing engines operate at Mach 5 to Mach 6, adds NASA's Michael Braukus in Washington, D.C.

Emotional teens

Teenagers' infamous mood swings may not be due entirely to the glands, ac-cord-ing to the newsletter of the Charles A. Dana Foundation, New York City. It also could have something to do with their developing brains.

Scientists at McLean Hospital, Belmont, MA, examined brain scans of healthy teenagers and adults to determine whether emotional or rational pathways in the brain are more active in the teen years. "Not surprisingly, emotions won hands down," adds the newsletter, The Dana Brain Daybook.

Activity in the center of the brain called the amygdala, which is in the temporal lobe, tags an event or situation with emotional significance, the newsletter adds. The amygdala can trigger an emotional and often a physical response even before the brain has a chance to mull over the situation consciously.

Youths from 10 to 18 showed higher activity in that part of the brain than adults did. Why? Maybe because as they age, people learn to temper their instinctive gut reaction response with a rational reaction.

"Adult brains use the frontal lobe to rationalize or apply brakes to emotional responses," said Deborah Yurgelun-Todd of McLean Hospital, who headed the study. "Adolescent brains are just beginning to develop that ability."

Why so hot?

David S. Chapman, an internationally recognized scientist in the field of global warming, will present the Seventh Annual William R. and Erlyn J. Gould Lecture on Technology and the Quality of Life, Sept. 23 in the University of Utah's J. Willard Marriott Library.

The lecture, which starts at noon in the library auditorium, is titled "Global Warming: Just Hot Air?" The public is invited to the event, which is free.

Chapman, who is professor of geology and geophysics and interim dean of the graduate school at the U., is able to trace warming and cooling cycles through the past 400 years. Using bore holes in Utah and other locations worldwide, he can discover minute fluctuations in temperature.

"This extension of the instrumental record of global warming helps us to decide whether greenhouse gas emissions or long-term natural cycles are responsible for our current warming," said the library's Adela C. Sussman.