Capturing a Rhino Rarity on Film

Wildlife experts say they have captured the first known photographs of the Javan rhinoceros, an animal that is so rare that some people doubted it still existed.

Scientists had feared that the creature, once plentiful throughout Asia, had become extinct, in part because its habitat had been heavily damaged by defoliants like Agent Orange during the Vietnam War. But Vietnamese continued to report glimpses of the elusive animal in the dense, hilly terrain of southern Vietnam, and scientists had found footprints that suggested seven or eight of the Javan rhinos still lived.

So the Washington-based World Wildlife Fund decided to work with local Vietnamese authorities to try to capture a picture of one of the rhinos. This spring, staff at the Cat Tien National Park just north of Ho Chi Minh City placed 10 cameras that are automatically triggered by infrared sensors throughout the park. One of the cameras finally captured three rhino images on May 11, one of which was released last week.

Scientists believe fewer than 10 of the animals remain in Vietnam. The only other known remaining population is about 50 animals in Indonesia.

Eggheads With Room to Shrink

The brains of more educated people shrink more as they age than the brains of less educated people, but the more highly educated don't seem to suffer greater memory loss or other mental deterioration as a result, according to a new study.

C. Edward Coffey of the Henry Ford Health System in Detroit and colleagues performed brain scans on 320 elderly volunteers ages 66 to 90. Those with more education tended to have the most cerebrospinal fluid around their brains, which indicates more brain shrinkage, the researchers found. For each year of education, the researchers found about one-third of a teaspoon more cerebrospinal fluid, according to a report in the July issue of the journal Neurology.

Nevertheless, those with greater education showed no signs of excess memory loss or other mental problems. This suggests that while education doesn't prevent brain shrinkage, it gives people a buffer that reduces the effects, the researchers say.

A Breath of Africa in Miami

There's more evidence of what a small world it really can be: Dust from Africa routinely ends up in the air that people breathe in Miami.

Joseph M. Prospero of the University of Miami reviewed 23 years of measurements of airborne particles collected at the university's Rosenstiel School of Marine and Atmospheric Sciences, which is located on an island off the coast near Miami.

Based on a chemical analysis of the samples, Prospero concludes that up to one-half of the dust in the air over Miami comes from Africa. Levels of African dust are highest in July and during periods of drought in Africa.

The findings suggest that southern states' efforts to comply with new Environmental Protection Agency rules aimed at reducing the amount of tiny particles in the air can be complicated by dust blowing in from other countries.

"There is no evidence that African mineral dust, in itself, constitutes a health problem," Prospero writes in the July 20 issue of the Journal of Geophysical Research. "However, a large fraction. . . of the dust mass does fall into the 'respirable' size range, and consequently, African dust can efficiently penetrate into the human respiratory system."

Estrogen and the Younger Look

In addition to keeping bones strong and hearts healthy, estrogen apparently also makes women look younger.

Ludwig Wildt and Teresa Sir-Petermann of the University of Erlangen in Germany conducted an experiment in which they guessed the ages of 100 women ages 35 to 55 when they first walked into a room at their outpatient clinic. The researchers then measured the women's estrogen levels.

Women with low estrogen levels looked older than they really were and visa versa, the researchers report in the July 15 issue of The Lancet, a British medical journal.

Among its many other functions, estrogen is known to reduce wrinkles and increase skin thickness and quality, the researchers note.

"The association between estrogens and sexual attractiveness has been widely discussed in both scientific and popular literature," the researchers wrote.

"However, the question how estrogens confer information and signals on attractiveness in the human female has seldom been addressed. Evidence has been accumulated in various species, including our own, that female attractiveness reflects reproductive competence."

CAPTION: Camera hooked to an infrared sensor photographed a rare Javan rhinoceros in a Vietnamese jungle.