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July/August 2001

The Laboratory
in the News

Commentary by
C. Bruce Tarter

Annual Certification Takes a Snapshot of Stockpile Stewardship

Sensing for Danger

It's the Pits in the Weapons Stockpile

Looking into the Shadow World

Patents

Awards


 

 

The Laboratory
in the News

More complexity in global climate prediction
Researchers Bala Govindasamy, Ken Caldeira, and Philip Duffy of Livermore’s Atmospheric Science Division reported in a recent issue of Geophysical Research Letters that cooling temperatures recorded on Earth from 1000 to 1900 could be attributed to changes in land use instead of to natural variations in climate.
Duffy, leader of Livermore’s climate and carbon-cycle modeling group, said that “the main way humans influence climate is by burning fossil fuels, which make greenhouse gases. But we also suspected that large-scale changes in land use contributed to climate changes.” To test their theory, the researchers performed computer simulations of two scenarios for climate development: one simulating natural vegetation conditions and one accounting for deforestation caused by agricultural land use.
During the 900-year period covered by the simulations, the regions that cooled more were the ones where there was deforestation and dense human activity. Over land in the U.S., there was a cooling of about 0.41 kelvin. The researchers explained that the darker colors of forests tend to absorb sunlight, thus trapping heat on Earth, while the fields of grain or corn in agricultural land are lighter-hued and reflect solar rays back into space. Duffy said, “People talk about planting trees as a way to slow global warming, [but our study] suggests that may not work. It. . .might not be a good idea.”
Caldeira commented, “This is an example of inadvertent geoengineering—we changed the reflectivity of the Earth and have probably caused a global cooling in the past. This is now probably being overwhelmed by our greenhouse gas emissions.”
Contact: Philip Duffy (925) 422-3722 (duffy2@llnl.gov).

Lab’s plague detection system gets results fast
Using a DNA-based test system developed at Livermore, biologists at Northern Arizona University were able to detect an outbreak of plague in prairie dogs so quickly that they could issue health warnings within hours.
“If we hadn’t gotten the warning out, someone could have gotten sick,” said Paul Keim, a microbiology professor who used the test. “The speed of the test made all the difference.”
The outbreak was the first time that the Livermore detection system was used to test for a disease in the environment—in this case, Yersinia pestis, the bacteria that cause plague, which is carried to fleas from prairie dogs. The system could accurately and speedily test for Y. pestis bacteria because it was based on the bacteria’s DNA signature, which had been developed
by Livermore scientists. Flea samples were subjected to the test and within six hours, the testing team had four positive readings and had initiated a series of preventive messages to the public.

The development of the Y. pestis signature is part of Livermore’s work on methods to monitor, detect, and counter infectious diseases or bioterrorism agents. Of its use in the plague outbreak, Livermore biomedical scientist Paula McCready said, “It’s very exciting, and it made all
the hard work we went through worthwhile. We did a lot of analysis to make sure these DNA signatures were unique to Yersinia pestis and nothing else in the environment.”
The use of genetic signatures to speedily monitor the spread of infectious diseases is based on a DNA detection method called polymerase chain reaction, or PCR. “Because at least some of a pathogen’s genes and its DNA are unique to it, PCR can be used to detect even a single germ in a very specific fashion,” said Keim. “The basic technology has been applied to many different diagnostic problems, but you have to know what the specific DNA codes are for each. Without these, it is like a computer without software. LLNL provided the DNA codes to detect plague.”
Contact: Paula McCready (925) 422-5721 (mccready2@llnl.gov).

Livermore will extend life of cruise missile warhead
Officials at the National Nuclear Security Administration of the Department of Energy have approved an agreement, signed by the directors of the Livermore, Los Alamos, and Sandia national laboratories, to assign the responsibility of refurbishing the W80 warhead to Livermore. Originally developed at Los Alamos, the W80 is carried by cruise missiles.
Los Alamos weapons scientists will continue to be responsible for the Mod 0 and Mod 1 warheads in the stockpile. Livermore, together with Sandia/California, will develop the next round of modifications, dubbed Mod 2 and Mod 3, as well as all future changes to extend the stockpile life of the warhead.
The assignment of responsibilities seeks “to accomplish a more balanced workload at the nuclear laboratories and tend to the current needs of the national stockpile.” The effort is expected to last five years, and an estimated 30 Livermore researchers will form the core group for the refurbishment project.
Contact: Don Johnston (925) 423-4902 ( johnston19@llnl.gov).

Distant stars individually imaged by Hubble
At the June meeting of the American Astronomical Society in Pasadena, California, Michael Gregg of the Institute of Geophysics and Planetary Physics at Livermore and the University of California at Davis presented some exciting images of stars. They were pictures he had taken of individual stars in a galaxy called NGC3379, located about 30 million light years from Earth. The pictures resulted from a collaboration in which Gregg, colleagues from the Space Telescope Science Institute, the Universidad Catolica de Chile, and the University of Hertfortshire, England, used the Hubble Space Telescope’s near-infrared camera and multiple-object spectrograph to capture images.
Infrared images help astronomers determine star composition and formation. This knowledge allows them to compare the galaxy in which the stars are found with the Milky Way and other nearby galaxies.
Gregg’s star pictures, the first instance of individual stars being resolved in infrared at such great distance, also show that the NGC3379 contains variable stars, which change in brightness over time. Some of them were no longer visible in images taken three months later. Because NGC3379 is an elliptical galaxy, one that is thought to contain few variable stars, Gregg said that current assumptions about elliptical galaxy evolution may need to be revised.
Contact: Michael Gregg (925) 413-8946 (gregg3@llnl.gov).

Advanced communications links in free space
The Defense Advanced Research Projects Agency (DARPA), a principal research and development organization for the Department of Defense, has funded the first phase of a project to develop powerful new capabilities for free-space communications, such as data transmission from Earth stations to satellites. Called Coherent Communications, Imaging, and Targeting (CCIT), the project would enable secure communications at speeds of several gigabits over ranges greater than 1,000 kilometers. And the transmitted three-dimensional images would be aberration-free.
Livermore is the lead organization for the $9.5-million Phase I work, which will be performed over two years. The team includes researchers from academic institutions and companies in microelectromechanical systems (MEMS), photonics, and aerospace. The team is responsible for modeling; coordinating MEMS development; integrating MEMS, photonics, and high-speed electronics into a prototype system; and demonstrating the concept. DARPA expects that the innovations and integrations achieved by this work will provide systems useful late into this century.
Says Eddy Stappaerts, the CCIT program manager at Livermore, “The CCIT program has the potential to be a major development in secure, free-space communications for a range of military applications as well as having a significant impact in the commercial arena.”
Contact: Eddy Stappaerts (925) 422-7307 (stappaerts1@llnl.gov).

 

 

 



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UCRL-52000-01-7/8 | August 29, 2001