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science at Kansas University
led with Mihaly Horanyi of the University of Colorado on a project to answer questions that puzzled scientists since Jupiter's probe.
Researcher helping unlock inner halo mysteries of Jupiter
Go no farther than the kitchen sink to get a sense of a new theory about the workings of lunar's peculiar envi-
workings of Jupiter's peculiar environment.
Researchers Tom Cravens of Kansas University and Mihaly Horanyi of the University of Colorado collaborated on a project to answer questions that puzzled scientists since the planet's dusty ring was discovered 16 years ago by two NASA space probes.
The duo focused on Jupiter's ring structure — especially a faint doughnut-shaped halo extending from the ring toward the planet.
"That halo continually drains out and fills as if a faucet came from the big ring," said Cravens, professor of physics and astronomy.
Cravens and Horanyi belie cles linger in the ring only before drifting toward the planet. Older estimates had yielded dust lifetimes of 100 years or more.
Draining Jupiter's 200 mile-thick ring creates a halo, or torus, 3,000 miles thick, the researchers said. This process is thought to be unique in the solar system.
A paper on their work was published in an issue of Nature, one of the world's leading science journals.
Thomas Armstrong, KU professor of physics and astronomy, said the new
"It's important to understand Jupiter. It's the largest planet in the solar system. In many ways, its presence probably has determined much of Earth's early evolution."
study would generate more than academic intrigue.
Thomas Armstrong, KU professor of physics and astronomy
"It's important to understand Jupiter. It's the largest planet in the solar system," said Armstrong, who had no part in the Nature article. "In many ways, its presence probably has determined much of Earth's early evolution."
comets, for example
He said some scientists believe Jupiter acts as a cleaning agent in the solar system. It influences whether Earth is struck by
The NASA-sponsored study incorporating sophisticated mathematical models and Voyager data indicated to Horanyi and Cravens the source of dust wasn't Jupiter's volcanically active moon, lo.
Instead, they said, dust grains come from the bombardment of tiny rock moonlets within the ring. The largest moonlets are Metis and Adrastea, each about 10 miles across. The smallest dust grains have diameters smaller than the thickness of a human hair.
"Just as a truck would generate a continual cloud of dust as it sped over bumps, dust is generated continually from the main ring of Jupiter by constant collisions with micrometeors," Horanvi said.
The researchers concluded the halo forms when solar radiation gives these dust grains a positive electrical charge. That charge
causes grains to oscillate inside the ring before losing momentum and spiraling rapidly toward Jupiter's surface, flaring the ring's inner edge.
Scientists had thought the planet's hot, gaseous environment was dominated by negatively charged lo dust.
Jupiter's ring is 150,000 miles in circumference and 3,500 miles from the outer to inner edge. The ring is invisible from Earth. The planet's diameter is 89,000 miles or it has a radius of 237
times that of Earth.
While Saturn's prominent rings were observed more than 300 years ago, rings around Jupiter, Uranus and Neptune were confirmed following the Voyager tour of the solar system beginning in 1977.
Cravens hopes NASA's Galileo spacecraft can relay more information about Jupiter's environment to Earth to enhance study of the halo. The 2 1/2-ton Galileo reached Jupiter Dec. 7 after a six-year journey.
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KUMC research team seeking missing link in battle against AIDS
KANSAS CITY, KAN. — Research at the Kansas University Medical Center on a virus that causes AIDS is more than monkey business.
Virologist Bill Narayan's 20-person research team figured out a way to infect rhesus macaque monkeys with the human form of the deadly virus.
It's a significant scientific accomplishment because testing of drugs and vaccines had been hindered since the virus that made humans ill didn't make animals sick. Scientists now can use a monkey to study the AIDS virus in a way more beneficial to humans.
"For the neighbor next door, it will allow me to screen vaccines and drugs against HIV much faster," "5 Naravan said.
HIV research has progressed slowly because it took 10 years for some humans to develop symptoms related to AIDS. That lag time made it impractical to study the effectiveness of anti-AIDS vaccines in men and women.
Narayan's team used special techniques to make a virulent form of the virus that attacked the monkeys.
Within six months of being infected with the new virus.
"With human research, you are at the mercy of the whims of the patient." Narayan said. "You have to deal with huge cohorts of people. It's very expensive, very time-consuming, very inconvenient."
Researchers will now be able to give experimental vaccines to monkeys and expose each to KU SHIV, Narayan said. Research findings will be generated faster, more cheaply and more accurately.
called KU SHIV, about 20 monkeys developed symptoms observed in humans.
"For the neighbor next door, it would allow me to screen vaccines and drugs against HIV much faster."
Between 1990 and 1995, 335,000 Americans developed symptoms of AIDS.
— Virologist Bill Narayan
The total does not include those who technically have AIDS because of low blood counts but are not actually sick.
Heterosexual transmission, the fastestgrowing category of HIV risk, largely explains the relatively high numbers among black women.
Black and Hispanic men were at sharply higher risk than others. One of every 350 black men and one every 650 Hispanic men developed AIDS symptoms during the first half of this decade. So did one of every 1,100 black women, one of every 1,800 white men, one of every 2,500 Hispanic women and one of every 15,000 white women.
African-American women are 17 times more likely than white women to get symptoms of AIDS after catching the virus through heterosexual contact.
The main reason AIDS cases have leveled off is the stabilization of the disease among gay white men. Since 1990, the number of homosexually transmitted AIDS cases rose 47 percent among black men while actually declining 1 percent among white men.
through heterosexual contact.
Narayan, Marion Merrell Dow distinguished professor at the medical center, said the research breakthrough wouldn't help people who already have AIDS.
However, he said, additional testing of monkeys might identify a vaccine that protects women from the virus during intercourse.
Interest from the scientific community in KUMC's findings has been overwhelming. Naravan said.
Or scientists might discover how to prevent a fetus from becoming infected, he said.
"Every researcher we've talked to has been interested," he said. "We've got tongues hanging out."
The National Institutes of Health was impressed enough to issue a four-year $1.6 million grant to continue the HIV research program. Seed money for 18 months of research came from Hoechst Marion Roussel, formerly Marion Merrell Dow.
Virologist Bill Narayan's 20-person research team figured out a way to infect rhesus macaque monkeys with the human form of the deadly AIDS virus.
Photos by Earl Richardson
SATURDAY, AUGUST 17, 1996 9B