Stuck Mars rover struck by dust storm
PASADENA, Calif., Aug. 26 (UPI) -- The U.S. space agency says its Mars rover Spirit, stuck in loose Martian sand since April, is losing power because dust is blocking its solar panels.
"The amount of electricity generated by the solar panels on Spirit has been declining for the past several Martian days, or sols, as a regional dust storm moved southward and blocked some of the sunshine at Spirit's location," NASA said. "The team operating the rover has responsively trimmed Spirit's daily activities and is keeping an eye on weather reports from observations by NASA's Mars Reconnaissance Orbiter."
Spirit's solar panels generated 392 watt-hours during the mission's Sol 2006 (Aug. 24), down from 744 watt-hours five sols earlier, but still generous compared with the 240 watt-hours per sol that was typical before a series of panel-cleaning events about four months ago.
"We expect that power will improve again as this storm passes, but we will continue to watch this vigilantly," said John Callas, project manager for Spirit and its twin, Opportunity.
Despite the power reduction, scientists at NASA's Jet Propulsion Laboratory are still testing strategies for getting Spirit out of the patch of soft soil where it is trapped. The team wants to begin sending drive commands to Spirit next month.
Prostate hormone therapy a risk to some
BOSTON, Aug. 26 (UPI) -- Hormone therapy for prostate cancer patients suffering congestive heart failure or heart attacks is linked to higher death risk, U.S. researchers say.
Hormonal therapy is used as a means for prostate gland cytoreduction -- prostate shrinkage.
Dr. Akash Nanda of Brigham & Women's Hospital Dana-Farber Cancer Institute in Boston and colleagues assessed 5,077 men with localized or locally advanced prostate cancer who were treated with or without a median of four months of hormone therapy followed by radiation therapy from 1997 to 2006, who were followed-up until July 2008.
During the study period, 419 men died. Of those, 200 had no underlying comorbidity, but 176 had one coronary artery disease risk factor and 43 had a history of known coronary artery disease resulting in congestive heart failure or heart attack.
The study, published in the Journal of the American Medical Association, found hormone therapy was not associated with an increased risk of all-cause mortality in men with no comorbidity -- 9.6 percent versus 6.7 percent -- or a single coronary artery disease risk factor after median follow-ups of up to five years.
However, for men with coronary artery disease -- congestive heart failure or heart attack -- after a median follow-up of 5.1 years, hormone therapy was associated with nearly twice the risk of all-cause mortality of 26.3 percent versus 11.2 percent, the study said.
Tropical storms linger over wet land
WEST LAFAYETTE, Ind., Aug. 26 (UPI) -- Purdue University scientists say they've determined tropical storms originating over oceans retain their strength after landfall when ground moisture is high.
The study of more than 30 years of monsoon data from India, led by Professor Dev Niyogi, showed tropical storms endure when ground moisture is high, but lose power over dry land.
"Once a storm comes overland, it was unclear whether it would stall, accelerate or fizzle out," said Niyogi, who also serves as Indiana's state climatologist. "We found that whether a storm becomes more intense or causes heavy rains could depend on the land conditions -- something we'd not considered. Thus far we've looked at these storms based mainly on ocean conditions or upper atmosphere."
Niyogi said tropical storms gain their strength from warm ocean water evaporation.
"The same phenomenon -- the evaporation from the ocean that sustains the storms -- could be the same phenomenon that sustains that storm over land with moisture in the soil," he said. "The storm will have more moisture and energy available over wet soil than dry."
Niyogi's team's findings appear in the journal Geophysical Research Letters.
New method may prevent disease inheritance
BEAVERTON, Ore., Aug. 26 (UPI) -- U.S. researchers say they have used implanted donor eggs to prevent the inheritance of a class of mitochondrial disorders in non-human primates.
Scientists at the Oregon Health Science University in Beaverton, Ore., said they transferred hereditary material from the egg of a primate mother into a donor female's egg from which the hereditary material had been emptied. The resulting eggs were fertilized with donor sperm and implanted in the mothers, producing offspring having mitochondria only from the donated egg.
Mitochondria are small structures inside cells that provide energy for the cell's activities. Mitochondria have their own DNA, and are inherited only through the mother's egg cells.
The researchers said defective mitochondria are associated with diabetes, some cancers, infertility and neurodegenerative disorders such as Alzheimer's, Parkinson's and Huntington's diseases.
"Pending further research, the findings hold the potential of allowing a couple to have a child who is biologically their own, but is free of any conditions associated with defects in maternal mitochondria," said Dr. Duane Alexander of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, which funded the research.
The study appears online in the journal Nature.
