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News Briefs II

Former Mayor Suffers Stroke

Los Angeles Times
LOS ANGELES

Former Los Angeles Mayor Tom Bradley was in serious condition late Thursday after suffering a stroke earlier in the day, leaving doctors concerned but cautiously hopeful about his chances of regaining the speech and movement lost in the episode.

Bradley suffered the seizure a day after undergoing successful triple-bypass heart surgery at Kaiser Permanente's Hollywood hospital. The five-term mayor has been hospitalized for the past two weeks, after suffering a heart attack as he returned after a business meeting.

"As to his prognosis, time will tell," said Fred Alexander, Bradley's lead doctor, at an afternoon news conference. "We don't like to speculate. We are hopeful that he will have a full return of function, but I cannot say that that will occur."

Early in the day, the 78-year-old Bradley lost all movement on his right side and was unable to speak. He initially responded "very poorly" to doctors commands.

Later in the day, Bradley seemed to recognize doctors and family members and was nodding in response to questions. He also regained some movement, wiggling his toes slightly.

Doctors speculated that a blood clot, perhaps originating in Bradley's heart, broke loose and became lodged in the left side of his brain.

Doctors said the bypass surgery itself had proven successful and that Bradley's blood pressure and heart rhythm were greatly improved following the operation. "He is very strong in that respect," Alexander said.

Scientists Discover Material That Behaves Unusually When Heated

Newsday

In a surprising reversal of normal behavior, a new ceramic-like material, called zirconium tungstate, shrinks rather than expands when it's heated, scientists reported Thursday.

The new material could help scientists overcome serious problems in electronics, optics, metallurgy and ceramics, researchers said - including helping keep silicon chips from expanding, and eliminating distortions caused by temperature changes in very precise mirrors.

"If you can mix it with other materials, you could compensate" for their temperature-induced changes in size, said physicist Thomas Vogt, at the Brookhaven National Laboratory in New York. "You could end up with materials that don't show any changes in shape, which could be very important."

Vogt said the new compound "is the only material we know that has this unusual behavior over such a very, very long temperature range." The strange behavior occurs consistently over a temperature range of 2,000 degrees Farenheit.

Unlike other substances, zirconium tungstate also expands as it cools. And it keeps on expanding as temperatures get down to almost absolute zero, or minus 459 degrees F. Water also expands as it hardens into ice, but only at a very specific temperature.

The behavior of the zirconium tungstate is so strange and unprecedented, in fact, that Vogt said he "immediately checked my temperature controls" to be sure the measurements were correct.

"We got very close to the absolute zero point, and the stuff was still expanding," Vogt said.

The strange properties of zirconium tungstate were discovered by chemist Arthur Sleight's team at Oregon State University. Vogt was collaborating in the research, analyzing the material with a flood of neutrons from the laboratory's high flux beam reactor.

Sleight said researchers see it mainly as "being blended into polymer (plastic) composites to bring thermal expansion down to zero, or in (electronic) circuit boards to bring expansion down until it matches silicon."

Comet Hyakutake's Mysterious X-Rays Astonish Astronomers

The Washington Post
WASHINGTON

Astonished astronomers have detected mysterious X-rays emanating from Comet Hyakutake as it sweeps past Earth toward the sun.

The first X-rays ever found coming from any comet, they are revealed in an image released Thursday by a team of U.S. and German astrophysicists using the German ROSAT satellite.

The discovery is surprising, the researchers said, because a comet is an icy ball of dirt, whereas X-rays - one of the most energetic forms of electromagnetic radiation - are most often associated with gases heated to a million degrees or more, such as flares on the sun, or with violent interactions involving subatomic particles.

"We had no clear expectation that comets shine in X-rays," said Michael J. Mumma, of NASA's Goddard Space Flight Center in Greenbelt, Md., a member of the international team that announced the finding Thursday. "Now we have our work cut out for us in explaining these data. But that's the kind of problem you love to have."

The team used the orbiting ROSAT - an X-ray observatory - to observe the comet repeatedly over a total of six hours, between March 26 and March 28. The image released Thursday was taken March 27, as the comet passed within 10 million miles of Earth.

Team leader Carey Lisse of Goddard and the University of Maryland said he considered the comet's close pass an opportunity too good to miss, even though he expected to find only low levels of X-ray emissions at best.

As it turned out, he said, the X-ray signal was about 100 times brighter than even his most optimistic calculations had predicted, and it fluctuated wildly within a few hours. "I was absolutely elated," he said. "This is something brand new. We'll be working on this for years."

"The whole thing was done on a lark, said Robert Petre, the United States' lead scientist for the ROSAT satellite. "Once we had the enormous signal, we had to go back and scratch our heads."

In the image, the X-rays appear to emanate from a crescent-shaped area of the coma, or halo, a vast sphere of gas and debris that surrounds the comet's tiny nucleus. The crescent is on the side of the halo that is pointed toward the sun.