November 8, 1996
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and feature story tips, please contact the public information officer at the end of each item at
(703) 292-8070. Editor: Beth Gaston
Contents of this Tipsheet:
A cryogenic (super-cold) test chamber filled with fluid helium will
soon allow researchers to test many central questions of physics
related to intense convection and turbulence. Turbulence, which can
limit the performance of high speed aircraft and the safety of
skyscrapers in high winds, is an important unsolved problem in
classical physics. The unconventional use of cryogenic helium in
turbulence studies will allow more extreme conditions to be tested in
the laboratory. With a $5 million NSF grant researchers will build
and refine a one-meter-tall prototype "cryostat," an insulated tank
filled with helium at temperatures minus 450F.
The information obtained will be more accurate over wider ranges of
turbulence than with other methods, according to University of Oregon
physicist Russell Donnelly. Donnelly and colleagues from Yale
University and Brookhaven National Laboratory will build the tank, to
become the heart of the Laboratory for Cryogenic Turbulence Studies at
the University of Oregon.
Technical limitations have kept scientists from creating wind
tunnel conditions with Reynolds numbers, used to represent turbulence,
much higher than ten million. This presents a major obstacle, since
the wind flowing over a jet's wing has a Reynolds number of about 70
million. Donnelly's device will achieve Reynolds numbers of 100
million. [Cary Lee Hanes]
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Fossils discovered on an NSF-funded expedition in Antarctica last
December show new evidence that freshwater crayfish evolved at least
65 million years earlier than previously thought. Researchers in the
Shackleton Glacier area discovered crayfish burrows in
240-million-year-old deposits of the Triassic Period, and identified a
fossil claw of the Late Carboniferous-Early Permian Age
(285-million-years-old).
The newly found crayfish claw is the oldest known evidence of
decapod crustaceans from freshwater deposits anywhere on earth.
Crayfish are important components of freshwater ecosystems because
they are large and abundant omnivores. Their presence in these very
old deposits suggests that freshwater ecosystems resembling those of
today developed much earlier than was thought. The breakage pattern
on the claw, which appears to have been caused by a predator or
scavenger, supports this theory by suggesting the presence of a
community of species.
Scientists have long speculated that decapod crustaceans invaded
freshwater stream and lake systems before the end of the Palezoic Era,
but had no direct evidence until now.
"This forces us to rethink how and where they evolved," said Dr.
John Isbell of the University of Wisconsin-Milwaukee, who took part in
the expedition with Dr. Molly Miller of Vanderbilt University. "We're
pretty excited -- we're starting to believe that Antarctica was not a
dead, barren world during the late Palezoic age." [Cary Lee Hanes]
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The NSF and the National Biological Service (NBS) have signed an
interagency agreement to contribute funds to support projects in
biodiversity informatics. This agreement includes support for the
Bishop Museum of Hawaii to develop an interdisciplinary information
model for biological collections, and for subsequent related projects
to make systematics, collections and other biodiversity data more
accessible through the National Biological Information Infrastructure
(NBII).
The newly developed information model will help foster increased
collaboration among biological collections institutions, according to
Jim Beach, program director in NSF's division of biological
infrastructure.
Development of a National Biological Information Infrastructure is
part of a broad cooperative effort to make data and information on
biological resources more accessible so they can be used to support
resource management decisions. The goal of the NBII is to establish a
distributed "federation" of biological data and information sources,
relying on a network of partners and cooperators to make the data they
generate and/or maintain available to others throughout this
federation using the Internet, thus facilitating biological data
stewardship. [Cheryl Dybas]
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