Pollution and JFK Jr.'s Flight

Air pollution may have contributed to the plane crash that killed John F. Kennedy Jr., his wife and sister-in-law, according to an atmospheric scientist.

Joseph M. Prospero of the University of Miami's Institute for Marine and Atmospheric Studies analyzed weather and pollution data for the Martha's Vineyard area the night of the July 16 crash. The "haze" in the area was actually air pollution, he concludes.

"At the time of Kennedy's flight, pollution levels were high over a large area extending from Ohio-Pennsylvania to the flight region," Prospero says in an unpublished analysis released last week. Satellite images show "a sharply defined band of very high particle concentrations over this same region."

During most of Kennedy's flight, his plane was well above the pollution. "Although he may have had some concerns about poor visibility towards the horizon, when he looked down through the shallow haze layer, he could have seen lights and other details with reasonable clarity, a factor that may have lulled him into complacency," Prospero writes.

But when Kennedy started to descend, he would have flown directly into the densest part of the pollution about 20 miles from the airport, according to Prospero.

"Under those conditions Martha's Vineyard and the horizon beyond were most likely completely invisible," he writes. "I suggest that the ultimate cause of the crash was a low-lying layer of pollution that disoriented him in the final moments of his flight, so close to his destination, invisible in the haze."

Aerobic Exercise as Brain Aid

There's new evidence that aerobic exercise can help elderly people think better.

Arthur F. Kramer of the University of Illinois at Urbana-Champaign and colleagues studied 124 previously sedentary subjects age 60 to 75 over a six-month period. Half of the subjects were put on a regimen of walking rapidly for 45 minutes three days a week while the others were put on a regimen of stretching and toning. The researchers performed a battery of tests on the subjects to gauge the effect of the exercise on them both physically and mentally. One of the mental skills tested was "executive control," which is the ability to switch tasks.

"We found that those who received aerobic training showed substantial improvements in performance on tasks requiring executive control compared with anaerobically trained subjects," the researchers report in the July 29 issue of Nature.

Aerobic exercise may improve decision-making skills by increasing oxygen flow to the front parts of the brain, the researchers say.

"The selective nature of the improvements produced by aerobic exercise, which affect only executive control processes supported by frontal and prefrontal regions of the brain, might explain the ambiguity of previous studies relating aerobic fitness with improved neurocognitive function."

Pain Tolerance May Be Genetic

People seem to respond differently to pain, and researchers have long thought that it's not simply that some are more stoical than others. Now, researchers have found new evidence that sensitivity to pain lies in our genes.

The researchers from Johns Hopkins University and the National Institutes of Health studied a gene that carries instructions for a molecule known as the mu opiate receptor, which is needed for the body's natural pain-killers and drugs like morphine to work.

When the researchers studied different strains of mice, they found that slight differences in the mu opiate receptor gene determined how many receptors the mice had in their brains. Mice with more receptors had a higher tolerance for pain and vice versa, the researchers report in the July 20 issue of the Proceedings of the National Academy of Sciences.

Studies of people similarly indicate that different people have different numbers of these receptors. The findings, the researchers say, could lead to new ways to alleviate pain.

Buckyballs From Space

There's more evidence that a newly discovered form of carbon occurs naturally in outer space.

Buckyballs are soccer ball-shaped carbon molecules discovered in 1985--only the third known form of pure carbon along with diamonds and graphite. They were subsequently detected at the site of a meteorite crater in Ontario. Fullerenes are similar carbon molecules that contain larger numbers of carbon atoms, creating different configurations.

In the new research, Luann Becker of the University of Hawaii and colleagues from NASA's Ames Research Center in California analyzed a piece of the Allende meteorite, which was found in Mexico. A chemical analysis produced evidence of buckyballs and other fullerenes, according to a report in the July 15 issue of Nature.

"Their presence in the Allende meteorite indicates that they can survive passage through space and subsequent processing in the interstellar medium, and the accretion process into grains and larger bolides (such as asteroids or meteorites), as well as arriving on planets such as Earth," the report says.

Because fullerenes contain hollow, cage-like structures that can hold gases, some scientists have speculated that buckyballs and fullerenes may have played a critical role in the evolution of life on Earth by carrying the building blocks for life to the planet.

"Fullerenes and high carbon clusters may have been important on the early Earth, and perhaps other planets, by providing not only a source of carbon, an essential element of life, but also the volatiles that contributed to the planetary atmospheres needed for the origins of life," the researchers say.