An Oct. 18 Science Notebook item incorrectly described a Canadian dinosaur discovery as the first dinosaur fossil found above the Arctic Circle. Many dinosaur fossils have been found in Alaska above the Arctic Circle. (Published 10/21/04)
Learning 2nd Language Early
Brain scientists have found evidence to explain why people who learn a second language when they are very young tend to be more proficient bilingual speakers -- learning two languages early in life appears to bulk up a key language center in the brain.
Andrea Mechelli of the University College in London and colleagues performed brain scans on 25 people who spoke only English, 25 English speakers who learned a second language before the age of 5, and 33 who learned another language between ages 10 and 15.
The gray matter in a part of the brain involved in language acquisition -- called the left inferior parietal cortex -- was denser in those who spoke two languages, and especially dense in those who learned the second language while very young, the researchers found.
The researchers then performed scans on 22 Italians who learned English as a second language and subjected them to detailed proficiency testing, and found the same thing -- with those who were most proficient having the most dense gray matter in that area.
Although it is possible that some people are genetically predisposed to acquiring a second language because they are born with this part of their brains being dense, it is more likely that learning the second language affects brain development, the researchers said.
"These results are consistent with growing evidence that the human brain changes structurally in response to environmental demands," the researchers reported in the Oct. 14 issue of Nature.
-- Rob Stein
Trade Restrictions on Bald Eagle
The United States last week helped ease international trade restrictions on the bald eagle, whose numbers have recovered on U.S. soil. Bush administration negotiators pushed for the change at the Convention on International Trade in Endangered Species of Wild Fauna and Flora in Bangkok, arguing that it will make it easier for Native American tribes in the United States and Canada to get permits for exchanging eagle feathers and parts for religious purposes.
Bald eagles are listed as threatened under the U.S. Endangered Species Act, but federal officials plan to propose delisting them because the number of breeding pairs has risen from 500 as of 40 years ago to 7,600 today.
Craig Manson, assistant secretary of the interior for fish and wildlife and parks, who led the U.S. delegation to the Bangkok meeting, said the birds are still protected by other laws.
"No one is going to be able to rush out and trade in bald eagle parts," Manson said. He added that the switch will cut paperwork in half by eliminating the need for import permits.
Some environmentalists questioned the move. James D. Gilardi, director of the World Parrot Trust, said it makes little sense for the administration to relax trade restrictions on the "symbol of the American ideals of freedom."
"This change in protection for the bald eagle underscores the degree to which the pro-trade forces in the Bush administration have run amok, even when it comes to our national bird," Gilardi said.
-- Juliet Eilperin
Dinosaur Fossils in the Arctic
Researchers have found the remains of a large meat-eating dinosaur on a bleak mountainside on an island off the north coast of Canada, the first dinosaur fossils discovered above the Arctic Circle.
Paleontologist Hans Larsson of McGill University's Redpath Museum described the foot bones and teeth found on Bylot Island as those of a large "tyrannosaurid," a group that includes Tyrannosaurus rex.
"There was not enough to say what particular species it was," Larsson said in a telephone interview. "But it's a large predatory dinosaur. We're just starting to open up a window on what life was like there."
Larsson said the fossil was about 75 million years old, embedded in stone, a set of rocky pinnacles that rose out of the sea just north of Baffin Island, nearly 400 miles north of the Arctic Circle.
"The rocks were deposited on the edge of a beach, so the whole environment up there was kind of like a temperate forest with lots of trees" at the time the dinosaurs lived, Larsson said.
He said he has unearthed evidence of extensive vegetation, as well as shark teeth and the remains of giant predatory sea animals known as mososaurs.
Larsson said researchers had previously discovered traces of dinosaurs in Alaska and the Canadian Yukon, but none north of the Arctic Circle. "It's almost just a matter of getting there," Larsson said. "The cliffs start at sea level and rise to 3,000 feet. Most of the work is prospecting."
-- Guy Gugliotta