In the News
Astronomers Observe Explosion from Early Universe
NASA's Swift satellite orbits the Earth trying to
detect gamma-ray bursts—massive explosions of radiation
released when giant stars died brilliantly long ago and collapsed
into black holes. The flashes of light last only seconds and never
get inside the Earth's atmosphere. The astronomers behind Swift were
rewarded in September when the satellite detected energy from one of
the blasts, pivoted quickly to determine its whereabouts and alerted
astronomers, including Daniel Reichart of the University of North
Carolina at Chapel Hill. Reichart rushed to a facility from
which he could control a telescope perched in the Andes Mountains.
He and undergraduate student Josh Haislip got the data they needed
on the afterglow of the burst, then determined that the explosion
was older and farther away than any explosion ever observed. It
occurred 13 billion years ago, only 700 million years after the Big Bang.
See NASA press release at http://www.nasa.gov/vision/universe/starsgalaxies/sburst05_pressrelease.html;
preprint at http://arxiv.org/abs/astro-ph/0509660.
Biologists Unveil Key to Genetic Variations Behind
Geneticists have completed a map of human genetic variation, a
sliver of the human genome—one-tenth of one percent. Genes
that contribute to diseases such as cancer, diabetes and
hypertension lurk among those variations, and the new map provides
an important tool for ferreting out the genetic markers of those
diseases. Before the map's publication, biologists had to scour all
3 billion individual nucleotides to spot individual variations,
called single nucleotide polymorphisms or SNPs. The new map
capitalizes on the revelation that SNPs can be spotted by looking
for variation at the level of haplotypes, larger strings of DNA that
are inherited together. That reduces to 1 million the number of
places to search for those variations that mark susceptibility to disease.
The International HapMap Consortium, A Haplotype Map of the
Human Genome, Nature 437:1299-1320 (October 27,
Mice-tro Kings Squeak Songs of Love
We're not the only musical species—birds, whales, dolphins and
gibbons are all known to sing, though the reasons aren't always
clear. Now we can add mice, thanks to an accidental discovery in a
Washington University lab. Neurobiologists were investigating what
goes on in rodents' brains when they sense sex pheromones. Recording
male mice as they sniffed cotton swabs treated with the urine of
females, they picked up a distinctive pitch, songs too shrill to be
heard by the human ear. A pitch-shifted playback revealed their
musical nature. The discovery could advance research into the
origins and causes of speech.
Holy, T. E., and Z. Guo. Ultrasonic songs of male mice.
Public Library of Science Biology 3(12):e386 (November 1,
Not Heavy Haulers, but Nanotrucks Are Neat!
Rice University engineers have built a fleet of tiny molecular
vehicles that could ferry nano-payloads. The nanocars and nanotrucks
are so small that 20,000 of them could line up across the width of a
human hair. They roll along on tiny pure-carbon buckyballs and
feature a suspension system allowing the vehicles to surmount atomic
obstructions. Objects built to the nanoscale—a nanometer is a
billionth of a meter—have some special properties. For
instance, the buckyball wheels are virtually indestructible because
each is a single molecule not likely to break up into its 60 atoms
Shirai, Y., et al. Directional Control in Thermally
Driven Single-Molecule Nanocars. Nano Letters 5 (11):
2330-2334 (November 9, 2005).