The U.S. electrical grid is a complex system of power plants, transmission lines, and local distribution networks that deliver power to homes and businesses. It comprises three major grids - Eastern, Western and Texas - which are divided into hundreds of smaller sections. A summary of how power flows on the system, who oversees it and what went wrong in the August 2003 blackout:
WASHINGTON (AP) - Scientists who sparked an outcry by creating easier-to-spread versions of the bird flu for research purposes want to try such experiments again using a worrisome new strain. This time around, the U.S. government is promising extra scrutiny of such high-stakes research up front.
NEW YORK (AP) - The U.S. electrical grid is better managed and more flexible a decade after its largest blackout but remains vulnerable to increasingly extreme weather, cybersecurity threats, and stress caused by shifts in where and how power is produced.
DETROIT (AP) - Nearly 51 hours after jumping into a lake near the Michigan-Canada border, a long-distance swimmer who calls himself "The Shark" finished his 22-mile journey to Detroit while hauling hundreds of pounds of bricks.
LOS ANGELES (AP) - In a rare diplomatic rebuke, President Barack Obama called off an upcoming Moscow summit with Russian President Vladimir Putin on Wednesday, sending a stern message of disapproval over Russia's harboring of National Security Agency leaker Edward Snowden.
INDIANA COMMUNITY HANDS OUT DRUG TESTING KITS: LAWRENCEBURG, Ind. (AP) - A southeastern Indiana school is distributing kits so parents can test their children for drug use.
RENO, Nev. (AP) - A biker gang leader was convicted of murder Wednesday in the 2011 killing of a Hells Angels member at a Nevada casino that authorities said was part of an orchestrated assassination plot to take out a high-ranking official of the rival group.
WASHINGTON (AP) - Smartphones don't make smart babies, an advocacy group declared Wednesday in a complaint to the government about mobile apps that claim to help babies learn.
ATLANTA (AP) - Higher blood-sugar levels, even those well short of diabetes, seem to raise the risk of developing dementia, a major new study finds. Researchers say it suggests a novel way to try to prevent Alzheimer's disease - by keeping glucose at a healthy level.
DES MOINES, Iowa (AP) - The allure of capturing the estimated $425 million Powerball jackpot had players in a buying frenzy Wednesday, further confirming a trend that lottery officials say has become the big ticket norm: Fatigued Powerball players, increasingly blase about smaller payouts, often don't get into the game until the jackpot offers big bucks.
FORT HOOD, Texas (AP) - On the first day Maj. Nidal Hasan went on trial in a fight for his life, he claimed responsibility for the 2009 shooting rampage at Fort Hood. He posed no questions to most witnesses and rarely spoke. On one of the few times he did talk, it was to get on the record that the alleged murder weapon was his, even though no one had asked.
LOS ANGELES (AP) - Coastal waters off California are getting more acidic. Fall-run chinook salmon populations to the Sacramento River are on the decline. Conifer forests on the lower slopes of the Sierra Nevada have moved to higher elevations over the past half century.
NEW YORK (AP) - Publishers who have settled an electronic book pricing dispute with the federal government objected Wednesday to penalties the government wants to impose on Apple Inc., saying it will hurt publishers rather than the personal electronics giant.
North Bend, Ore. (AP) - David Wonnacott qualified for a tattoo license on July 5 and wasted little time establishing a business in a small, coastal Oregon community. Problem is, police said, he did it with a gun.
SECAUCUS, N.J. (AP) - The Children's Place has stopped selling a T-shirt that sparked complaints of sexism.
CAPE CANAVERAL, Fla. (AP) - Scientists have uncovered a vast ocean beneath the icy surface of Saturn's little moon Enceladus.
FORT HOOD, Texas (AP) - The soldier who killed three people at Fort Hood may have argued with another service member prior to the attack, and investigators believe his unstable mental health contributed to the rampage, authorities said Thursday.
SEATTLE (AP) - A decade before a colossal landslide buried a Washington community, county officials considered buying up people's homes there to protect them from such a disaster.
SYRACUSE, N.Y. (AP) - A city board on Thursday gave a Muslim group the go-ahead to remove six crosses from the roof and spires of a century-old former Catholic church so the now-vacant Gothic structure can be used as a mosque.
BOULDER, Colo. (AP) - Good news for people who are sticklers for punctuality: The National Institute of Standards and Technology has a new atomic clock that isn't supposed to gain or lose a second in roughly 300 million years.
LOS ANGELES (AP) - Three of eight people who contracted bacterial meningitis this year have died, and all three had sex with other men, Los Angeles County health officials said Thursday.
WASHINGTON (AP) - A sense of belonging to the middle class occupies a cherished place in America. It conjures images of self-sufficient people with stable jobs and pleasant homes working toward prosperity.
DENVER (AP) - Organizers of Denver's annual April 20 marijuana festival on Wednesday announced that rapper B.o.B and singer Wyclef Jean will headline the event as they try to draw a big post-legalization crowd and shake the memory of last year's event, which was marred by a still-unsolved shooting.
TRENTON, N.J. (AP) - The Food and Drug Administration said Wednesday that it has approved the first tablet in the U.S. for gradually reducing hay fever symptoms, an alternative to months of weekly doctor visits for uncomfortable allergy-desensitizing shots.
FORT HOOD, Texas (AP) - A gunman opened fire Wednesday at Fort Hood in an attack that left four dead, including the shooter, law enforcement officials said.
WASHINGTON (AP) - The Supreme Court's conservative majority voted Wednesday to free wealthy donors to give to as many political candidates and campaigns as they want, further loosening the reins on giving by big contributors as the 2014 campaign moves into high gear.
DENVER (AP) - A Wyoming college student visiting Denver on spring break jumped to his death after eating a marijuana cookie that his friend legally purchased in one of Colorado's recreational pot shops, authorities said Wednesday.
HARTFORD, Conn. (AP) - Some Newtown residents are calling for the Sandy Hook Elementary School shooter's home to be torn down and replaced with a park or nature preserve, according to a new community survey.
EVERETT, Wash. (AP) - As medical examiners painstakingly piece together the identities and lives of the 29 people known killed when a mudslide wiped out a small Washington community, one mystery troubles them.
CINCINNATI (AP) - A Cincinnati man pleaded guilty to the accidental shooting death of his 11-year-old daughter during a drunken fight with the girl's mother and was sentenced Wednesday to six years in prison.