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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: Cheryl Dybas Contents of this News Tip:
U.S. CENTRAL PLAINS VULNERABLE TO GLOBAL CLIMATE CHANGEBy analyzing how the northern U.S. Central Plains changed from forest to grassland and back again during past climate changes, ecologists funded by the National Science Foundation (NSF), and affiliated with Duke University in North Carolina, have offered further evidence that the region will likely undergo drastic ecological changes due to 21st-century global climate change. The scientists believe the region responded to climate changes lasting decades or centuries during the mid-Holocene period (8,000 to 4,000 years ago) by flip-flopping between grassland and forest. During this period immediately after the last ice age, the region underwent many short-term cycles of warming and cooling. "We're finding that this system is really responsive," says James Clark, a botanist at Duke, "with the grasslands expanding eastward into forests, then retreating." One reason this region is so susceptible to climate change effects, says Clark, "is that it lies at the boundary between two air masses that have very different climates associated with them. Subtle changes in the factors that affect atmospheric circulation can translate into shifts in the boundaries where these air masses meet. And small changes in those boundaries can change the climate from a prairie climate to a forest climate." [Cheryl Dybas] RESEARCHERS CRACK STEP IN CODE OF GENE ACTIVATIONLike a cryptographer seeking to crack incredibly complex code, biochemist Jerry Workman of Penn State University has unraveled new components of a cell's gene-reading process. Workman's research, funded in part by the NSF, has contributed to the discovery of two large groups of proteins called histone acetyltransferase (HAT) complexes. Workman was among the first to isolate individual HAT complexes; he found one HAT enzyme, Gcn5, that untangles nucleosomes, densely knotted clumps of DNA. Further experimentation has shown, however, that HAT complexes only untangle nucleosomes already attached to "code-breakers" -- transcription-activating proteins. When these transcribing proteins attach to a gene that a cell has turned on, the HAT complex allows nucleosomes physical access to the gene, creating a "bridge" between nucleosome and gene. "This research reveals previously unknown aspects of gene activation and demonstrates how interactive gene-copying proteins are," says Workman. [Greg Lester] WORLD'S PREMIER SOLAR TELESCOPE REDEDICATED TO HONOR ITS CREATORNSF will honor astronomer Richard Dunn for his lifetime contributions to solar research on September 30, 1998, by renaming the Vacuum Tower Telescope (VTT) of the National Solar Observatory at Sacramento Peak, New Mexico. The telescope will be called the Richard B. Dunn Solar Telescope. The innovative design of the Vacuum Tower Telescope -- developed by Dunn -- revolutionized the capabilities of solar telescopes by evacuating air to reduce image deterioration. The design has been incorporated into every major solar telescope since the VTT was put into operation in October, 1969. Although one of the oldest operational vacuum telescopes, the VTT still maintains the best image quality and instrumentation in the world, say astronomers. Dunn, known for his excellence in building telescopes and instrumentation that have substantially increased mankind's knowledge of the sun, retired from the National Solar Observatory on August 31, 1998. Goetz Oertel, President of the Association of Universities for Research in Astronomy, Inc., commented, "I am delighted that we are able to recognize Dick Dunn's many contributions to solar astronomy during his past forty-five years of service to the National Solar Observatory. Dick gave heart and soul to this telescope. Now he is giving it his name." [Yvette Estok]
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