in the News
Virulence in Plague
Decontaminates Better Than Bleach
Inspections of Laser Coatings
Kilobytes to Petabytes in 50 Years
in the News
detection of salmonella
Biomedical scientists Peter
Agron and Gary Andersen have developed a DNA-based detection system
for identifying the presence of the salmonella pathogen, a major
cause of food poisoning in humans. In a paper published in November
2001 in Applied & Environmental Microbiology, Agron and
Andersen described their work to develop a DNA signature that will
cut down the time usually taken to identify Salmonella enteritidisthe
strain that causes bacterial infectionsfrom as long as 2 weeks
to as short as 2 hours.
During a year-long research
effort, Agron and Andersen identified unique segments of DNA in
S. enteritidis. They used a technique called suppression
subtractive hybridization to compare the DNA of similar strains
of Salmonella and determine what fragments of the DNA of
enteritidis were unique and therefore the basis of its signature.
Then they designed primers, or DNA markers, of the unique enteritidis
regions. The primers were replicated many times using the polymerase
chain reaction, and the replicated regions were processed to identify
and characterize S. enteritidis unambiguously.
Coauthoring the journal article
with Agron and Andersen were Jessica Wollard, also of Lawrence Livermore;
Richard Walker, Sherilyn Sawyer, and Dawn Hayes of the California
Animal Health and Food Safety Laboratory in Davis, California; and
Hailu Kinde of the California Animal Health and Food Safety Laboratory
in San Bernardino, California.
Contact: Peter Agron (925) 423-1284 (firstname.lastname@example.org)
or Gary Andersen (925) 423-2525 (email@example.com).
for explosives simulants increases
A California company with
ties to the Laboratory predicts that its business will grow as a
result of the September 11 attacks.
Van Aiken International,
located outside Los Angeles, expects that the need to train more
dogs to detect explosives and the increased screening of airline
baggage for explosives will put a high demand on the explosives
simulants that it is manufacturing under license from Lawrence Livermore.
Some 6 years ago, researchers
at Livermore began developing high-explosive simulants, primarily
to train bomb-sniffing dogs in real-life situations without posing
a hazard. John Kury, project leader of the program, said that he
and his team were trying to develop a full suite of simulants to
match commercial explosives, gunpowders, and plastic explosives
similar to those used to down the Pan Am flight over Lockerbie,
Kury said that the simulant
developed at the Laboratory contains just 8 percent of explosive,
has passed all Department of Transportation tests, and is not classified
as hazardous. It can be detected by trained dogs, and it looks like
an explosive to an
x-ray machine because it has the same density and average atomic
number as real explosives.
Contact: John Kury (925) 422-6311.
affected global temperature
Satellite measurements of
temperature, which began to be collected in 1979, have shown little
or no warming in the lower troposphere. These data have been cited
to support skepticism of global warming. But recent research by
atmospheric scientists has explained the apparent difference in
warming rates at Earths surface and in its lower troposphere.
In a paper published in November
2001 in the Journal of Geophysical Research Atmospheres,
these scientists presented their discovery that large volcanic eruptions
cooled Earths lower troposphere more than the surface and
likely masked the actual warming of the troposphere..
The conclusion is presented
in Accounting for the Effects of Volcanoes and ENSO in Comparisons
of Modeled and Observed Temperature Trends. The work was performed
by Laboratory researchers Benjamin Santer, Charles Doutriaux, James
Boyle, Sailes Sengupta, and Karl Taylor, who teamed with scientists
from the National Center for Atmosphere Research; National Aeronautics
and Space Administration/Goddard Institute for Space Studies; the
Climatic Research Unit at the University of East Anglia, United
Kingdom; and the Max Planck Institute for Meteorology, Germany.
The scientists used a statistical
procedure to quantify
the volcanic influences on surface and tropospheric temperatures.
To do so, they also had to separate out the effects of El Niño
events, which coincided with both of the eruptions they were studyingEl
Chichón in Mexico in 1982 and Mount Pinatubo in the Philippines
Our recent work shows
that some of the differences between warming rates at the Earths
surface and in the lower troposphere are due to the effects of volcanic
eruptions and stratospheric ozone depletion, said Santer,
the lead author. Both of these factors probably cooled the
lower troposphere by more than the surface, for physical reasons
that are well understood. Without ozone depletion and the recent
eruptions of El Chichón and Pinatubo, it is highly likely
that the lower troposphere would have warmed over the last two decades.
These conclusions were reinforced by results from numerical models
of the climate system.
Contact: Benjamin Santer (firstname.lastname@example.org).
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April 15, 2002