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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: Tom Garritano Contents of this News Tip:
Why Surfaces Stick: No Longer a Dirty SecretIt takes no more than a speck of grime from your fingertip to make things stick. Most people know that static friction accounts for the initial shove needed to start sliding down a ski slope or to push a heavy piece of furniture across the floor. Traditional laws of friction describe this phenomenon, but they haven't explained its origin at the molecular level. In fact, molecular-scale models have concluded that static friction between two surfaces shouldn't exist. Now a team of National Science Foundation (NSF)-supported physicists has developed a theory -- backed by detailed molecular modeling -- that may explain why surfaces lock together and resist sliding. The key is that microscopic impurities like dust, dirt and stray molecules coat the surfaces and prevent smooth motion. Even fingerprints or moisture can be culprits. "We've shown that grime from the air can stop any pair of surfaces from sliding -- and that this grime can explain the 300 year-old laws of friction that are taught in Freshman Physics," says physicist Mark Robbins of Johns Hopkins University. Robbins and two colleagues from Germany reported their theory in a recent issue of Physical Review Letters. [Amber Jones] Computer-Scientists Honored by National Academy and Leading Professional SocietyNSF’s Directorate for Computer and Information Science and Engineering (CISE) is well-represented among recently announced individual honors for excellence in information technology. The highest honor given to a computer scientist is the Association for Computing Machinery’s Turing Award, named for a pioneer in the field, Alan Turing. Andrew Yao of Princeton University is the 2001 winner. He conducts CISE-funded research in quantum computation, which promises to eventually replace traditional silicon in a new generation of chips that use fundamental physical processes to achieve tremendous speed. The award includes a $25,000 prize and is given for technical contributions "of lasting and major technical importance to the computer field." Several current and former recipients of CISE funds are among those elected this year to the National Academy of Engineering. They include Massachusetts Institute of Technology’s Nancy Lynch and Dimitri Bertsekas, Princeton’s Vincent Poor, Stanford University’s John Cioffi, University of Tennessee’s Jack Dongarra and University of Washington’s Edward Lazowska. [Tom Garritano] For more about the Turing Award, see: http://www.acm.org/awards/taward.html Biologists Uncover Darwin's "Missing Evidence" for Divergence of Species--In a Warbler's SongBiologists funded by NSF and affiliated with the University of California at San Diego (UCSD) have demonstrated, in a study of the songs and genetics of a series of interbreeding populations of warblers in central Asia, how one species can evolve into two. The investigators have discovered intermediate forms of two reproductively isolated populations of songbirds that no longer interbreed. This work provides evidence predicted by Darwin in support of his theory of evolution. "One of the largest mysteries remaining in evolutionary biology is exactly how one species can gradually diverge into two," says Darren Irwin, a biologist at UCSD who headed the study. "This process, known as speciation, is very difficult to study because it can take a great deal of time to occur." The warbler is the first case in which "we can see
all the steps that occurred in the behavioral divergence
of two species from their common ancestor," says Irwin.
"These results demonstrate how small evolutionary
changes can lead to the differences that cause reproductive
isolation between species, just as Darwin envisioned."
[Cheryl Dybas]
NSF is an independent federal agency that supports fundamental research and education across all fields of science and engineering, with an annual budget of nearly $4.5 billion. NSF funds reach all 50 states, through grants to about 1,600 universities and institutions nationwide. Each year, NSF receives about 30,000 competitive requests for funding, and makes about 10,000 new funding awards.
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