WASHINGTON NASA is delaying a mission to Mars that already had been over budget and will get even more costly.

WASHINGTON Many of the thousands of troops who suffered traumatic brain injuries in Iraq and Afghanistan are at risk of long-term health problems including depression and Alzheimer's-like dementia, but it's impossible to predict how high those risks are, researchers say.

LONDON When you're smiling, the whole world really does smile with you.

ANCHORAGE, Alaska A conservation group is going to court to force the federal government to consider adding the Pacific walrus to the list of threatened species.

ATLANTA Measles deaths worldwide declined dramatically to about 200,000 a year, continuing a successful trend, global health authorities reported Thursday.

WASHINGTON NASA has set a May date for its space shuttle mission to fix the Hubble Space Telescope for a final time.

NEW YORK What does a teenage brain on Google look like? Do all those hours spent online rewire the circuitry? Could these kids even relate better to emoticons than to real people? These sound like concerns from worried parents. But they're coming from brain scientists.

CLEVELAND The Cleveland Clinic says it will publicize the business ties its 1,800 doctors and researchers have with drug companies and device makers.

RIYADH, Saudi Arabia The Saudi government has found excessive amounts of the industrial chemical melamine in powdered milk imported from China and lower concentrations in chocolate wafer cream made in Malaysia.

NEW YORK More than 400 years after Danish astronomer Tycho Brahe challenged established wisdom about the heavens by analyzing a strange new light in the sky, scientists say they've finally nailed down just what he saw.

NEW YORK Consumers should be wary of Web sites from clinics that offer stem cell treatments, says a study that found a lack of firm medical evidence to back up their claims. The Web sites in the study generally portrayed their therapies as safe, effective and ready for routine use, but published research doesn't support that "overoptimistic" picture, the study authors said.

CHICAGO Unique brain wave patterns, spotted for the first time in autistic children, may help explain why they have so much trouble communicating.

BEVERLY HILLS, Calif. A Danish adventurer is first in line to ride aboard a privately funded, two-seat rocket ship designed by a California rocket maker to fly about 37 miles above Earth.

CHICAGO Imagine sitting in a dark room all day, evaluating CT scans and other medical images on a computer screen but never actually seeing real patients. That's life for many radiologists.

WASHINGTON Doctors-in-training are still too exhausted, says a new report that calls on hospitals to let them have a nap. Regulations that capped the working hours of bleary-eyed young doctors came just five years ago, limiting them to about 80 hours a week.

STOCKHOLM, Sweden Shaking hands with yourself is an amusing out-of-body experience. The illusion of having your stomach slashed with a kitchen knife, not so much. Both sensations, however, felt real to most participants in a Swedish science project exploring how people can be tricked into the false perception of owning another body.

LONDON Faith was breathing for Hope. So when the newborn conjoined Williams twins were separated, it turned out that Hope couldn't live without her sister.

CHICAGO More than half a million U.S. children have autism with costly health care needs that often put an unprecedented financial strain on their families, national data show.

Patients with asthma and other lung diseases should stay tuned: Quick-acting albuterol inhalers aren't the only lung medicines poised for changes because they're powered by ozone-damaging chemicals called CFCs.