Stories of modern science ...

By JIM KLING, UPI Science Writer  |  Nov. 2, 2001 at 4:46 AM
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, Nov. 2 (UPI) --


All objects contain tiny vibrations of thermal energy, and now researchers believe they can use those random vibrations to perform measurements without using an energy source. In the Sept. 24 issue of Physical Review Letters, University of Illinois professor of theoretical and applied mechanics Richard Weaver and research associate Oleg Lobkis took measurements in a block of aluminum at room temperature. "The sound we were listening to was created by arbitrary thermal fluctuations generated elsewhere in the sample, such as an electron hitting a (crystal) imperfection or an air molecule striking the surface," Weaver said. "While no one had really doubted that these tiny fluctuations existed, no one had ever measured them before." The passive technique could work on nearly any object, but would be most helpful in applications where conventional sound sources are scarce. At very low frequencies, for example, seismologists could pick up the random vibrations from distant earthquakes to obtain local stratigraphic information without setting off directed explosives.


That sleep is essential to learning has been a long-held truism, but it is discounted by a report in this week's edition of the journal Science. The rapid eye movement (REM) stage of sleep -- when dreaming occurs -- is not important to memory formation, UCLA neuroscientist Jerome Siegel determined after reviewing human and animal studies. "Sleep loss interferes with concentration. For this reason, cramming for exams during periods of sleep loss is not a good academic strategy. Similarly, taking exams while sleepy will interfere with performance. However, it does not appear that sleep is required for memory formation," said Siegel. Among the evidence: A class of drugs known as MAO inhibitors eliminate REM sleep for as long as months or years, and researchers found that they had no impairments to memory.


A bandage that changes color when dangerous bacteria get into the wound could tell patients when to seek a doctor's care, or even what antibiotics would most effectively treat the infection. The device, developed by researchers at the University of Rochester, is one of a series of devices being designed to work in conjunction in the home to monitor a family's health. The researchers invented a sand-grain sized wafer that can differentiate between two classes of bacteria, called Gram-positive and Gram-negative, and they intend to expand it to be able to identify other types of bacteria, including salmonella, listeria and enteropathogenic E. coli, all of which can cause serious disease in humans. Currently, researchers identify Gram-positive and Gram-negative bacteria using a stain and a microscope, but that takes time and can be prone to human error. The smart bandage "is an important step in changing the way preventive medicine is perceived and practiced," said Alice Pentland, chair of the department of dermatology at the University of Rochester. The application of the technology could go beyond bandages. For example, in Third World countries, where pollution is a threat to drinking water, plastic cups could be designed to turn bright red if there are pollutants present. "We may even see this technology being used as an early warning in the case of biowarfare," said Benjamin Miller, assistant professor of chemistry at the University of Rochester.


African lions may be facing extinction in many parts of the continent, according to a New Scientist report. A commission organized by the World Conservation Union (IUCN) says that none of the populations in West or Central Africa are large enough to be viable, meaning that the genetic stocks could be weakened, producing unfit individuals. Lions in East Africa are relatively well off, with thousands of lions present. The current survey uses "estimates based on being in the field from time to time," said Hans Bauer of Leiden University in the Netherlands. Researchers believe that a population needs at least 100 breeding pairs -- 500 to 1000 animals total -- to retain enough genetic diversity to avoid inbreeding. None of the populations in the region have anywhere near that number. "It's a serious situation," said Bauer. "There's not one population that we can be sure will continue to be there." "It might seem like there are a lot of lions, but they have become a completely fragmented population," said Will Travers of the Born Free Foundation in London. Not all agree. A World Wildlife Foundation spokesman said the organization does not work with lions "because they're not endangered."

(Editor; for more information on vibrations, call (217) 244-1073; on sleep, call (310) 794-2265; on bandages, call (716) 273-4726)

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