July 9, 1998
For more information on these science news and feature story tips, please
contact the public information officer at the end of each item at (703)
292-8070. Editor: Cheryl Dybas
Contents of this News Tip:
The world's most land-loving crab is a thin and delicate Jamaican species
that spends its entire life in a tree. And it has made a surprisingly
rapid evolutionary transformation from its large and rugged ocean-dwelling
ancestors, according to genetic research performed by National Science
Foundation (NSF)-funded biologists at Pennsylvania State University.
"These very unusual crabs, which are the most terrestrial of any in
the world, live in little pockets of rainwater inside bromeliad plants,
which grow on the branches of tropical trees," explains S. Blair Hedges,
an evolutionary biologist at Penn. State. The tiny bromeliad crabs are
less than an inch long, and are thin enough to squeeze between the leaves
at the base of the bromeliad plant, where rainwater collects.
Because the bromeliad crab looks and behaves so differently from its
ocean-dwelling relatives, scientists thought the two species must have
needed a long time--on the order of 50 million years--to evolve from their
last common ancestor. But, according to Hedges, the Jamaican land crab
evolved from one common Jamaican marine ancestor as recently as four million
years ago. "This date makes sense," adds Hedges, "as it corresponds to
a time in Jamaica's geologic history when the land had risen far enough
out of the sea to provide new ecological niches for the ancestral marine
crab. That ancestor then began evolving strategies for living entirely
on land. Such rapid adaptation is not common in nature." [Cheryl Dybas]
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Access to computers has increased substantially in the past decade,
and more people are using the Internet for practical purposes, according
to Jon Miller, vice president of the Chicago Academy of Sciences.
Miller regularly conducts public surveys on science literacy and understanding
for NSF's Division of Science Resources Studies. Since 1983, he has included
questions on computer (and related technology) usage in the NSF survey
of U.S. adults. Resulting data -- published in Science
and Engineering Indicators 1998 -- illustrate that computer usage
is broad and growing in America.
Households with computers have increased from 8 percent in 1983 to
43 percent in 1997; and 11 percent of Americans report more than one working
computer in their home. A third of Americans own a home computer that
includes a modem.
"People are beginning to use the Internet and web facilities to get
information on health and science," said Miller. "Approximately 30 million
adults had looked for specific information on the Web during the year
preceding the 1997 interview," he said. Miller notes, however, that a
difference related to educational level remains. The data show, for example,
that nearly 90 percent of college graduates in the U.S. use a computer
at home or work, compared to 60 percent of high school graduates and 21
percent of those who did not complete high school.
"In regard to information technology and resources, we are becoming
a more polarized society -- those citizens with a college education have
greater access to this new technology are able to gain access to and utilize
information more easily," he said. [Mary Hanson/Bill Noxon]
For more information, see: http://www.nsf.gov/sbe/srs/stats.htm.
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Mona, the Signing AvatarTM, expresses herself through articulated
arm and hand movements complemented by life-like facial expressions. The
3D virtual human, developed by Seamless Solutions, Inc. (SSI) of Orlando,
Florida, uses all the visual cues necessary to communicate in sign language.
Research for the Signing AvatarTM facial animation was begun
through the NSF's Small Business Innovation Research Program.
Some 50 movable joints and more than 1,200 deformable surfaces let
Mona interact with users through smooth, detailed, gestures. New and highly
efficient algorithms enable developers to use fluid web animations with
less loss of detail through compression. With the new technology, SSI
plans to create learning tools for deaf students and to supplement educational
software, or work independently over the web.
Mona has already received good responses from her first users, students
at the Florida School for the Deaf and Blind in St. Augustine. With further
testing to come, SSI plans to begin integrating Mona and her counterparts
into commercial software within the next two years. [Greg Lester]
For more information, see: http://www.seamless-solutions.com.
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