Science Now Discoveries from the world of science and medicine
Watch: Man controls a robotic arm with his thoughts

The day Erik Sorto reached out to grab himself an ice cold beer was a major step forward for brain science.

Sorto is quadriplegic and has been unable to move his own limbs since a bullet wound severed his spinal cord 12 years ago.

In the years since his injury, Sorto managed to attend college and write a gang prevention book, but one thing that frustrated the 34-year-old most of all was that he couldn't pick up a cold one and drink it at his own pace without having to ask a caregiver for help.

"Drinking a beer by myself gives me hope that somehow in the future I can regain a lot more independence," he said.

Sorto still can't move his own arms and legs, but after two years of hard and often frustrating work, he is able to use his thoughts to control a robotic arm. And he is able to do this with enough dexterity that he can now tell the arm to pick up a bottle of beer, bring it to his mouth, hold it there while he sips from a straw and set it down when he is done.

The neuroengineering that...

Read more
In overweight teens, food ads appeal to mouth and brain

When a sitcom's laugh track stops and the camera pans seductively up the height of a glistening bacon cheeseburger, the teen brain snaps to attention - especially if that brain sits atop a body that carries excess fat, a new study says.

In teens with higher proportions of body fat, the brain's pleasure centers respond more robustly to fast-food advertising than they do in leaner teens, researchers have found. Even the regions of the brain that anticipate and process fast-food's sensory qualities send up a more robust response in fattier teens than in those with less fat.

The finding, published Thursday in the journal Cerebral Cortex, suggests the intriguing possibility that adolescents on a trajectory toward adult obesity "may simulate eating behaviors" when they are visually prompted by advertising, the study authors said. That "may then contribute to the enactment of the behavior itself," they added.

Repeated over time, those responses may all conspire to make weight loss harder later...

Read more
3,400 years after her death, scientists track a girl's travels

In 1921, archaeologists exploring an ancient burial mound near Egtved, a village in Denmark, unearthed the grave of a girl estimated to have been 16 to 18 years old when she died.

Not much remained of her body — only some hair, teeth, nails, and bits of skin and brain — but scholars could tell a lot about her. Dressed in fine woolen clothing, with a bronze medallion on her belt that probably represented the sun, the Egtved Girl, as she came to be known, was believed to be a person of high status. She was buried with the cremated remains of a small child and a bark bucket that once contained beer. Analysis of the oak coffin in which she lay revealed that she died about 3,400 years ago.

This week, nearly a century after she was discovered, a team of researchers in Denmark filled in more detail of the Egtved Girl’s life story. By analyzing chemicals in her body and in the items in her coffin, they were able to surmise that she hadn’t been born in Denmark, that her diet lacked protein from...

Read more
Dogs split from the wolf pack earlier than thought, DNA analysis suggests

A new analysis of ancient wolf DNA has shed new light on the murky early history of man's best friend, suggesting that dogs split from wolves as many as 27,000 to 40,000 years ago -- not 11,000 to 16,000 years ago, as earlier genome research had proposed.

"Dogs may have been domesticated much earlier than is generally believed," Love Dalen, a researcher at the Swedish Museum of Natural History in Stockholm and coauthor of a study describing the discovery in the journal Current Biology, said in a statement.

Dalen, first author Pontus Skoglund of the Harvard Medical School and their colleagues came to their conclusion after sequencing the DNA of a male wolf that lived on Siberia's Taimyr Peninsula.

The genetic material came from a small piece of rib bone collected during an expedition to the region. The team was unsure at first if the sample came from a modern or ancient wolf; radiocarbon dating revealed later that the beast, which they referred to as Taimyr 1, lived about 35,000 years ago.


Read more
Cold weather is much deadlier than extreme heat, study says

Extreme heat waves like the one that killed more than 70,000 Europeans in 2003 may be the most visible examples of deadly weather, but cold days actually cause more deaths than hot ones, a new study says.

After examining more than 74 million deaths that occurred in 13 countries from 1985 to 2012, researchers calculated that 7.3% of them could be attributed to cold weather and 0.4% to hot weather.

In another counterintuitive finding, extreme weather — either hot or cold — was responsible for only 11% of the weather-related deaths, according to the study published Thursday in the journal Lancet.

“Heat stroke on hot days and hypothermia on cold days only account for small proportions of excess deaths,” the international research team wrote.

The researchers collected daily data on weather conditions, air pollution and deaths from 384 cities around the world. For each city, they calculated the temperature at which deaths were least likely to occur. All other days were compared to days with...

Read more
Study of views on gay marriage should be retracted, coauthor says

A highly publicized study that purported to show how face-to-face interactions can change people's views on same-sex marriage is being disavowed by one of its authors who now says he has doubts about the data.

The study, published last December by the journal Science, claimed that when gay canvassers in Los Angeles County knocked on a door and lobbied a household resident about same-sex marriage, the resident was more likely to form a lasting and favorable opinion of gay marriage than if they were lobbied by a heterosexual canvasser. 

Coauthors Michael LaCour, a doctoral candidate in political science at UCLA, and Donald Green, a political science professor at Columbia University, noted at the time the report was published that they were initially so skeptical of the results that they reran their experiment. The results were the same, they said.

But as the report was covered by news organizations nationwide -- including the Los Angeles Times -- another group of researchers began to question...

Read more