Artery disease linked to air pollution
Air pollution may cause and accelerate artery disease by helping to narrow carotid arteries, according to a study a University of Southern California professor presented at the American Heart Association's annual conference in New Orleans.
Nino Kuenzli said his team analyzed data from two clinical trials of 798 Los Angeles residents over 40 to determine how fine-particle pollution produced by power plants, automobiles and other sources causes artery damage.
After adjusting for several factors, including smoking and age, the scientists concluded that an increase of 10 micrograms per cubic meter in fine-particle pollution led to an increase of as much as 4.3 percent in the thickness of artery walls. Such thickening can lead to calcification and ruptures, which block blood flow to the heart and cause heart attacks.
"Our study found that air pollution may contribute to cardiovascular problems at a very early stage of the disease, similar to smoking, and enhances atherosclerosis, which is the underlying disease process of cardiovascular diseases," Kuenzli said. "It's speeding up the aging process."
-- Washington Post
Fossil plant may have answer to origin of seeds
Scientists have rediscovered the plant structure that seems to have given rise to seeds 385 million years ago.
A fossil plant first reported in 1968 and recently reanalyzed by researchers from Belgium and France appears to possess a primitive seed. Seeds were an innovation in plant evolution; today seed plants comprise more than 250,000 living species.
In the journal Science, the scientists describe the seed precursors, which are about one-quarter inch long with a pollen-catching head. The head protrudes above protective tissues, suggesting that the earliest seeds were pollinated by wind.
-- Dallas Morning News
Pair of Mars rovers still going strong
The Mars rovers Spirit and Opportunity are still going strong after nearly nine months of exploration, overcoming wear and tear to scale a mountain on one side of the planet and plow deep into a valley on the other.
Ray Arvidson of Washington University in St. Louis, the deputy lead scientist for the NASA mission, said in a briefing that Spirit's investigations on the slopes of the "Columbia Hills" suggested that the formation was created by volcanic activity.
The Columbia Hills -- about 300 feet high and four miles long -- are an older geological outcrop rising out of the younger plain where Spirit landed in January. Spirit has problems with its wheels but is able to function normally, Arvidson said. The rovers were designed to operate for three months.
Opportunity is on the other side of the planet exploring "Endurance Crater" and is heading briskly uphill toward "Burns Cliff," an exposure of layered sedimentary deposits, after bogging down for several days in deep sand and dust drifts in the crater bottom.
Rover project manager James Erickson, of NASA's Jet Propulsion Laboratory, said Opportunity had benefited from a pair of mysterious "cleaning events" that appeared to have removed dust from the solar arrays, enabling the batteries to charge to 80 percent of their original capacity.
-- Washington Post