in the News
measures to save the Salton Sea
California has long been
using more than its allotment of Colorado River water and now is
under mandate to reduce that usage. One way the state plans to achieve
the reduction is to save on agricultural water usage.
In the Imperial Valley agricultural
region of southern California where such saving is being proposed,
one concern has to do with the effects of conservation on the aquatic
ecosystem at the Salton Sea, which depends on agricultural runoff
to keep its salt levels down. If runoff were decreased, dilution
would decrease, the Salton Seas salt levels would rise, its
fish would die, and the migratory birdsfor which the sea is
a key stopwould have no food.
At the request of California
Representative Duncan L. Hunter, Livermore researchers conducted
studies to come up with recommendations on how to stave off increased
salinity in the Salton Sea. The researchers recommended that irrigation
canal water that has seeped into the ground, on the order of some
145,000,000 cubic meters per year, be reclaimed and fed into the
Salton Sea. They also proposed the construction of evaporation ponds
to extract salt from the sea. And they are looking at ways to use
geothermal energy to desalinate Salton Sea water and then pump it
Dave Layton, division leader
for the Laboratorys Health and Ecological Assessment Division
and one of the researchers on this project, said that the proposal
requires more study and drilling of test wells to see if it is worthwhile
to pump water into the Salton Sea. He added, In any event,
the use of groundwater would only constitute an interim measure
and would have to be linked to management actions regarding other
potential mitigation measures for the Salton Sea.
Contact: David Layton (925) 422-0918 (email@example.com).
detectors also protect food supplies
Livermore biomedical scientist
Paula McCready told her audience at a meeting of the American Society
for Microbiology last May that The tools we use to develop
DNA signatures for the detection of bioterrorist agents could also
be used to search out food-borne pathogens.
DNA signatures, the regions
of DNA unique to specific organisms, are being identified much more
quickly as a result of advances in DNA sequencing. What used to
take years to find has been condensed to a period of weeks or months.
This is important because now DNA signatures can be quickly developed
for new strains of pathogens.
And using those signatures
in another applicationto find the bacteria that cause food
poisoningallows laboratories to more rapidly identify their
presence in food and in the environment. The diagnostic tests to
identify such food bacteria have been lessened from hours and days
to under one hour because scientists no longer need to culture and
prepare samples before analysis.
We can tailor our tests
to distinguish harmful forms of different organisms from the benign
forms, says McCready. Among the bacteria that could be identified,
according to her, are Camphylobacter, a bacterium present
in undercooked chicken, or Salmonella, a bacterium that can
be found in eggs, juice, fruit, or vegetables.
Livermore researchers and
other biomedical scientists have developed highly accurate DNA signatures
for the bacteria that cause plague and anthrax as well as for other
organisms. This work has been performed in collaboration with Los
Alamos National Laboratory researchers and the Bioterrorism Rapid
Response and Advanced Technology Laboratory of the Centers for Disease
Control and Prevention in Atlanta.
Contact: Paula McCready (925) 422-5721 (firstname.lastname@example.org).
it over diamonds in stiffness
Stiffness is the measure
of a materials compressibility. The stiffest materials also
tend to be the hardest ones. But in the case of diamonds and osmium,
the former is still the hardest, even though the latter is stiffer.
This surprising information was discovered by Laboratory physicist
Hyunchae Cynn, who decided to look at osmium because its stiffness
had never been accurately measured. It caught my eye,
When the bulk modulusresistance
to compressionof osmium turned out to be higher than that
of diamond, no one really believed it. So Cynn crushed the osmium
under 60 gigapascals of pressure in a diamond-anvil device and looked
at the resulting x-ray diffraction patterns to determine the spacing
between crushed osmium atoms. The data gave osmium a bulk modulus
of 462 gigapascals compared with the 443 gigapascals for diamond.
Because osmium is so different
from other materials with high bulk modulus, Cynn says that researchers
should take a closer look at metals and other materials to see if
they might have missed discovering any properties simply because
the properties were unexpected.
Contact: Hyunchae Cynn (952) 422-3432 (email@example.com).