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Sept. 20 (UPI) -- NASA's SeaWiFS satellite now 10 years old GREENBELT, Md., Sept. 20 (UPI) -- The National Aeronautics and Space Administration is celebrating the 10th anniversary of its Earth-orbiting SeaWiFS satellite.

SeaWiFS (Sea-viewing WIde Field-of-view Sensor instrument) was launched Aug. 1, 1997, and shortly thereafter took its first measurements of ocean color. A decade later, the satellite is still helping researchers investigate the planet's changing climate by providing a global view of ocean biological productivity.

"SeaWiFS allows us to observe ocean changes and the mechanisms linking ocean physics and biology and that's important for our ability to predict the future health of the oceans in a changing climate," said Gene Carl Feldman, SeaWiFS project manager at NASA's Goddard Space Flight Center in Greenbelt, Md.

The satellite orbits Earth 14 times a day, measuring visible light over every area of cloud-free land and ocean once every 48 hours.

Stephanie Henson of the University of Maine said such observations are essential to understanding how changing global climate impacted ecosystems in the past,and how it might do so in the future.

Henson is lead author of a study involving SeaWiFS that was published last month in the Journal of Geophysical Research-Oceans.

Human testicles can provide stem cells NEW YORK, Sept. 20 (UPI) -- U.S. scientists said adult stem cells found in human testicles might be used in place of controversial embryonic stem cells to help fight diseases.

Weill Cornell Medical College researchers used spermatogonial progenitor stem cells, or SPCs, obtained from mice testes to form so-called multi-potent adult spermatogonial-derived stem cells. Those cells developed into endothelial cells and tissue, as well as cardiac cells, brain cells and a variety of other cell types.

Prior research used genetic manipulation to reprogram adult cells derived from connective tissue to acquire stem-cell potential, differentiating into various organ-specific tissues, the scientists said. However, that reprogramming method -- called "induced pluripotency" -- carried an increased risk of transforming into malignant cells.

"Some hurdles remain … nevertheless, it appears that these unique specialized spermatogonial cells could be an easily obtained and manipulated source of stem cells with exactly the same capability to form new tissues that we see in embryonic stem cells," said senior study author Dr. Shahin Rafii.

The research is reported in journal Nature.

Ancient bog provides global warming clues BRISTOL, England, Sept. 20 (UPI) -- British scientists said sediments taken from a British bog suggest methane emissions increased due to intense global warming around 55 million years ago.

The study -- led by Richard Pancost and colleagues at the University of Bristol -- showed carbon isotope values of hopanoids (compounds made by bacteria) suddenly decreased in a manner that the scientists said can only be explained by switching to a diet of methane. That, they said, suggests methane emissions must have increased at that time.

The team that included scientists from the University of London and other institutions analyzed the geochemical composition of sediments taken from the Cobham Lignite wetland in southeast England.

"Fifty-five million years ago, a massive release of carbon into the atmosphere caused significant global warming," said Pancost. "It is likely that this warming and associated climate change caused a change in environmental conditions that brought about increased methane emissions. This in turn, may reflect an increase in methane production and subsequent release from the terrestrial biosphere."

The research is detailed in the current issue of the journal Nature.

Study: Steroids make home runs easier BOSTON, Sept. 20 (UPI) -- A U.S. study suggests that while steroid use produces only modest muscle mass increases, it can boost baseball home run production by 50 percent or more.

Tufts University physicist Roger believes the recent increase in the number of home runs coincides with the dawn of the "steroid era" in sports during the mid-1990s, and that the surge quickly dropped to historic levels in 2003 when Major League Baseball instituted steroid testing.

"A change of only a few percent in the average speed of the batted ball, which can reasonably be expected from steroid use, is enough to increase home run production by at least 50 percent," he said.

Tobin acknowledges athletes today achieve at a higher level than did athletes of the past, and that, along with other factors, could affect major league batting.

"Physics cannot tell us whether a particular home run was steroid-assisted, or even whether an extraordinary individual performance indicates the use of illicit means," said Tobin.

But he said analysis of the physics, combined with physiology, "suggest that some suspicion is reasonable."

The research is to be published in an upcoming issue of the American Journal of Physics.

Copyright 2007 by United Press International

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