WASHINGTON, June 13 (UPI) -- A study comparing fluoride toothpaste in 48 countries found it is too expensive for the world's poorest people, U.S. and Dutch researchers said.

COLUMBIA, Mo., June 11 (UPI) -- U.S. scientists say they have solved the mystery of what caused "New England's Dark Day" on May 19, 1780, by finding evidence of massive Canadian wildfires.

UPI Almanac for Saturday, May 31, 2008.

WASHINGTON, May 27 (UPI) -- Security risks are becoming an issue in the U.S. presidential race since Democratic contender Barack Obama is nearing his party's nomination, observers say.

BOCA RATON, Fla., May 27 (UPI) -- Mike Jarvis was named the men's basketball coach at Florida Atlantic University Tuesday.

ARLINGTON, Va., May 27 (UPI) -- Imagine that in 1902, Secretary of War Elihu Root had told U.S. President Teddy Roosevelt the difficulty of suppressing the Philippine Insurrection proved future weapons would need to be useful in conducting irregular warfare. I know, you aren't so clear on what the Philippine Insurrection was. But it was a big deal at the time: 130,000 U.S. troops were deployed in a multiyear counterinsurgency campaign, and more than 4,000 of them died. U.S. forces tortured prisoners. Insurgents committed atrocities. Very messy.

NEW YORK, May 21 (UPI) -- The former head of a New York historical society pleaded guilty to stealing two letters written by George Washington and Abraham Lincoln.

MINNEAPOLIS, May 16 (UPI) -- U.S. communities watching their neighborhoods crumble due to foreclosures are striking back by filing lawsuits, observers of the mortgage crisis said.

ARLINGTON, Va., May 10 (UPI) -- The apparent disappearance of skunks from Arlington County, Va., could indicate a larger problem in the region, experts say.