Jon Hamilton

The more exposure children have to chemicals called perfluorinated compounds, the less likely they are to have a good immune response to vaccinations, a study just published in JAMA, the Journal of the American Medical Association shows.

The finding suggests, but doesn't prove, that these chemicals can affect the immune system enough to make some children more vulnerable to infectious diseases.

You may want to read this twice if you're older than 45. In fact, you may have to.

That's because your mental abilities are already in decline, according to a study of 7,390 British civil servants just published in BMJ, the British Medical Journal.

2011 may go down as the year of the retraction in the scientific world.

Among the highly publicized discoveries that got debunked this year: a genetic basis for longevity; a new form of life; an explanation for autism; and a link between a virus and chronic fatigue syndrome.

All of these non-discoveries have something in common. They involved findings that both scientists and the public badly wanted to believe.

A little brain stimulation seems to speed up recovery from a stroke.

This isn't the sort of brain stimulation you get from conversation. It's done using an electromagnetic coil placed against the scalp.

Researchers think the treatment encourages brain cells to form new connections, allowing the brain to rewire itself to compensate for damage caused by a stroke.

If you read the ingredient list on a can of soup, you're likely to see items like carrots, wild rice, perhaps some noodles. What you won't see listed: BPA.

But a little canned soup for lunch can dramatically increase exposure to the chemical, according to a study in the Journal of the American Medical Association.

The study confirms that canned food is a source of BPA exposure. But it does nothing to clear up the question of whether this sort of exposure to BPA has health consequences.

Scientists say they are beginning to understand why brain injuries are so common in very premature infants — and they are coming up with strategies to prevent or repair these injuries.

The advances could eventually help reduce the number of premature babies who develop cerebral palsy, epilepsy or behavioral disorders such as ADHD, researchers told the Society for Neuroscience meeting in Washington, D.C., this week.

If you've been counting on your daily dose of merlot to stave off mortality, you might want to consider Plan B.

The links between red wine and longevity aren't nearly as strong as they once seemed, according to new research in the journal Nature. In fact, the research calls into question the whole mechanism used to explain wine's power to extend life.

Sorry, oenophiles.

It turns out daddies are losing more than just sleep after a child arrives. New fathers also experience a sharp decline in levels of the male sex hormone testosterone.

At least that's what scientists have concluded from a long-term study of more than 600 men in the Philippines.

The scientists found that single men who started out with relatively high testosterone levels were more likely than other men to become fathers. But once a baby arrived, testosterone levels plummeted.

Scientists say they have figured out how a very clever virus outwits a very hungry caterpillar.

The caterpillar is the gypsy moth in its larval stage, and the invasive species damages roughly a million acres of forest in the U.S. each year by devouring tree leaves.

But the damage would be greater if it weren't for something called a baculovirus that can infect these caterpillars and cause them to engage in reckless, even suicidal behavior, scientists say. The virus is so effective that the government actually sprays it on trees to help control gypsy moth outbreaks.

Animals have a special place in the human heart. Now, researchers are reporting that creatures great and small also have a special place in our heads.

A team led by researchers at Caltech has found individual brain cells that respond when a person sees an animal, but not when that person sees another person, a place, or an object.

Forecasters don't expect Hurricane Irene to make landfall until Saturday. But for nearly a week now, big-box retailers like Walmart and Home Depot have been getting ready.

They've deployed hundreds of trucks carrying everything from plywood to Pop-Tarts to stores in the storm's path. It's all possible because these retailers have turned hurricane preparation into a science — one that government emergency agencies have begun to embrace.

Scientists say there's a link between climate and violent conflict.

A statistical analysis of civil conflicts between 1950 and 2004 found that in tropical countries, conflicts were twice as likely to occur in El Nino years. The analysis appears in the journal Nature.

El Nino occurs when there is unusually warm water in the Pacific Ocean near the equator. But it affects weather patterns in tropical countries around the globe.

NASA, the agency best known for exploring space, is trying to answer some urgent questions about air pollution right here on Earth.

For much of July, the agency flew research planes between Washington, D.C. and Baltimore as part of a mission known as DISCOVER-AQ. The planes, along with weather balloons and ground stations, were gathering data on how pollutants such as ozone and particulates behave in the atmosphere.

The letters O-C-D have become a punch line to describe people who make lists or wash their hands a lot. But for some people with obsessive-compulsive disorder, the intrusive thoughts and rituals are severely disabling and don't respond to drugs or behavioral therapies.

So doctors have been trying a new treatment for OCD: deep brain stimulation.

Deep brain stimulation is best known as a way to reduce the tremors of Parkinson's disease. A surgeon places wires deep in the brain that carry electrical impulses from an implanted device a bit like a pacemaker.

A experimental device that delivers electrical pulses to the forehead can help control epileptic seizures, say scientists at the University of California, Los Angeles.

The device works by stimulating the trigeminal nerve, which runs just beneath the skin covering the eyebrows. Electrical signals follow that nerve to areas in the brain where seizures often begin, researchers say.

The group that advises the U.S. government on vaccination thinks some new vaccines may not be worth the cost.

In 2009, the Advisory Committee on Immunization Practices, or ACIP, decided it's not cost effective to routinely vaccinate boys for human papillomavirus, though they do recommend the vaccine for girls. Now the group is struggling to decide whether infants and toddlers should get costly new vaccines to prevent a form of meningitis caused by bacteria.

Scientists have finally demonstrated that sex is useful.

A team from Indiana University found that worms that have sex were better able than asexual worms to stay one evolutionary step ahead of dangerous parasites.

The finding, published in the journal Science, provides the first direct evidence that sexual reproduction improves a species' ability to survive in a fast-changing environment. And it suggests that parasites, including bacteria and viruses, are one reason species developed sexual reproduction in the first place.

The next time you're delayed by rain or snow at an airport, consider this: it's possible that an airplane actually caused the bad weather.

When aircraft fly though certain clouds, they can trigger a chain of events that causes precipitation for miles around, according to a study in the journal Science.

The idea for the study came in 2007, when a plane full of weather scientists flew through a very odd snowstorm near Denver International Airport.

Government officials are forecasting a turbulent future for the nation's weather satellite program.

Federal budget cuts are threatening to leave the U.S. without some critical satellites, the officials say, and that could mean less accurate warnings about events like tornadoes and blizzards. In particular, officials at the National Oceanic and Atmospheric are concerned about satellites that orbit over the earth's poles rather than remaining over a fixed spot along the equator.

Tornadoes have killed at least 530 people in the U.S. this year, the highest death toll since 1950.

But researchers say they are working on new detection and forecasting technologies that could help reduce tornado deaths in the future.

One of those technologies got put to the test on May 24 when a tornado touched down near Chickasha, Okla., and began heading northeast at near freeway speed.

Scientists say they have finally figured out how smoking helps people keep off extra pounds.

It turns out that nicotine activates a pathway in the brain that suppresses appetite, according to a study in the journal Science. This discovery should lead to better diet drugs, the researchers say.

The finding comes after decades of research showing that smokers tend to be a bit thinner than nonsmokers, and that smokers who quit tend to put on weight.

A technology that monitors electrical activity in the brain could help identify infants who will go on to develop autism, scientists say.

The technology, known as electroencephalography, or EEG, is also providing hints about precisely how autism affects the brain and which therapies are likely to help children with autism spectrum disorders.

Scientists say electroencephalography or EEG could help identify infants who are likely to develop autism. The technology detects unusual electrical patterns in the brain that are associated with autism.

A group of scientists has formally challenged the conclusions of a highly publicized report describing a mysterious microbe that seemed to thrive on a diet of arsenic.

The report, published in December by the journal Science, suggested that a bacterium found in California's Mono Lake was able to substitute arsenic for phosphorous, one of several elements considered essential for life.

There have been nearly 1,200 tornadoes in the U.S. so far this year. That's nearly twice the usual number of twisters, and it comes as something of a surprise to the scientists who study them. It turns out there is still no good way to predict tornado outbreaks more than a couple of days ahead of time.

Every year, government meteorologists tell the public about how many hurricanes to expect during the Atlantic season. But the government doesn't do that with tornadoes.

So far this year, there have been nearly 1,200 tornadoes in the U.S. That's close to twice the usual number — and it comes as something of a surprise to the scientists who study them.

Hearing gossip about people can change the way you see them — literally.

Negative gossip actually alters the way our visual system responds to a particular face, according to a study published online by the journal Science.

The findings suggest that the human brain is wired to respond to gossip, researchers say. And it adds to the evidence that gossip helped early humans get ahead.

Wounded troops often spend months in physical therapy to regain strength in their damaged bodies. Now, the military is trying something similar for military personnel with injured brains.

The Department of Defense is using computerized brain training programs to help personnel with traumatic brain injuries.

The approach is intended for people like 1st Lt. Frederick Simpson.

An old technology is providing new insights into the human brain.

The technology is called electrocorticography, or ECoG, and it uses electrodes placed on the surface of the brain to detect electrical signals coming from the brain itself.