SCIENCE

Notebook

Revenge of the Muggles?

Harry Potter and his pals Ron and Hermione have been scooting undetected around Hogwarts for years beneath the invisibility cloak Harry got from his murdered father, but now an international team of theoretical physicists suggests that muggles, or non-wizards, might someday make a cloak of their own.

Reporting last week in the journal Science, physicists J.B. Pendry of Imperial College London and David R. Smith and David Schurig of Duke University described a way to make high-tech "metamaterials" that can funnel light around an object and make it invisible.

Metamaterials, assemblages of small artificial bits of patterned metal films, can be engineered to bend almost any kind of electromagnetic energy. Schurig said that "probably this year," scientists will produce a metamaterial that can shield equipment from microwave radiation but that protecting objects from visible light -- creating an invisibility cloak -- is "further out," he said in a telephone interview -- "maybe 10 years."

Smith compared the process to a stream flowing around a stone -- essentially creating a "hole" in the water, where anything can be hidden and remain unnoticed from the outside: "We have shown it can be done for almost any frequency," he said in a telephone interview. "Being able to build it is another story."

Schurig said the first invisibility devices would probably be rigid "shells" rather than supple cloaks, "but, in principle, cloaks would be possible."

Harry and his friends will still have the advantage, though, because while metamaterials would make you invisible, they would also isolate you from the outside world. You wouldn't be able to spy on anyone. Like a Romulan Bird of Prey (at least until "Star Trek: Nemesis"), you'll have to decloak before attacking.

-- Guy Gugliotta

Sacrificing to Avoid Obesity

Almost half of Americans would give up a year of their life to avoid being fat, according to a recent survey.

The online survey of 4,283 of Americans ages 13 to 79 also found that between 15 and 30 percent would rather leave their marriage, give up the possibility of having children, be depressed or become an alcoholic than be obese. Five percent said they would rather lose a limb, and 4 percent said they would rather be blind.

"We were surprised by the sheer number of people who reported they would be willing to make major sacrifices to avoid being obese. It drives home the message that weight bias is powerful and pervasive," said Marlene B. Schwartz of Yale University, who led the team that reported the results in the journal Obesity.

The primary purpose of the survey was to gauge anti-fat bias. People of all weight categories exhibited a significant implicit bias against people who are overweight, but thinner people tended to be more biased, the researchers found.

"The fact that even obese individuals exhibited a significant implicit anti-fat bias is important because it suggests that they have internalized negative stereotypes, such as believing they are lazy," Schwartz said.

-- Rob Stein

Nitrogen Dioxide a Serious Risk

Nitrogen dioxide pollution in the air can kill people, according to a new study published last week in the European Respiratory Journal.

The paper -- which was written by Klea Katsouyanni and Evangelia Samoli, professors at the Department of Hygiene and Epidemiology at the University of Athens, and several other European researchers -- draws on data from 15 European cities and looks at the kind of pollution that is emitted largely by diesel engines.

Looking at heart- and lung-related deaths in the days after nitrogen dioxide exposure, Katsouyanni and Samoli found an increase of 10 micrograms of NO2per cubic meter of air increased deaths from heart and lung conditions by 0.40 percent and 0.38 percent, respectively.

Bart Ostro, chief of the California Environmental Protection Agency's air pollution epidemiology unit, said the paper is "way more suggestive than many other studies" in terms of linking nitrogen dioxide to mortality. He added that although more study is needed, it is one of the reasons California is on the verge of adopting new nitrogen dioxide standards -- including a one-hour exposure level-- that are stricter than federal regulations.

"The effects are so severe, we don't feel like we can risk being wrong," he said.

-- Juliet Eilperin