Amnesty International and Friends of the Earth Tuesday said they had filed an official complaint against Anglo-Dutch firm Shell for shirking responsibility for oil spills in Nigeria and wreaking havoc on the environment.

A joint statement said Shell's operations in the southern oil-rich Niger Delta breached the Organization for Economic Cooperation and Development (OECD)'s guidelines for responsible business.

The best way to not forget a newly learned poem, card trick or algebra equation may be to take a quick nap, scientists surprised by their own findings reported.

In experiments, researchers in Germany showed that the brain is better during sleep than during wakefulness at resisting attempts to scramble or corrupt a recent memory.

Will Lonesome George ever become a dad?

Scientists are still hoping to mate the near century-old giant tortoise from the Galapagos — even though efforts over the past two decades have failed.

Experts use different parts of their brains than amateurs, maximizing intuition, goal-seeking and pattern-recognition, said a study out Thursday that examined players of shogi, or Japanese chess.

Researchers used magnetic resonance imaging (MRI) scans to compare the brain activity of amateurs and professionals who were presented with various shogi board patterns and were told to think of their next move.

The U.N.'s World Meteorological Organization said Thursday that 2010 was the warmest year on record, confirming a "significant" long-term trend of global warming.

The trend also helped to melt Arctic sea ice cover to a record low for December last month, the WMO said in a statement.

Scientists have pinpointed a molecular mechanism in mice which helps skin cancer cells confound the animal's immune system, according to a study released Wednesday.

The discovery -- if duplicated in humans -- could one day lead to drug treatments that block this mechanism, and thus the cancer's growth, the study reported.

Japanese researchers will launch a project this year to resurrect the long-extinct mammoth by using cloning technology to bring the ancient pachyderm back to life in around five years time.

The researchers will try to revive the species by obtaining tissue this summer from the carcass of a mammoth preserved in a Russian research laboratory, the Yomiuri Shimbun reported.

A climate of uncertainty in the U.S. space program combined with the approaching retirement of the shuttle missions presents safety risks, a government advisory panel said Thursday.

"Lack of clarity and constancy of purpose among NASA, Congress, and the White House is a key safety concern," the Aerospace Safety Advisory Panel said in its annual report.

Tagging penguins with flipper bands harms their chances of survival and breeding, a finding which raises doubts over studies that use these birds as telltales for climate change, biologists said on Wednesday.

The metal bands, looped tightly around the top of the flipper where it meets the body, have long been used as a low-cost visual aid by researchers to identify individual penguins when they waddle ashore.

NASA said Tuesday it will aim to launch the space shuttle Discovery on February 24, after engineers found a way to shore up cracks on the external fuel tank that have delayed its final liftoff.

NASA engineers have been working since November to figure out why cracks were emerging on the 22-foot-long U-shaped aluminum brackets, called stringers, on the shuttle's external fuel tank.