UPI NewsTrack Health and Science News

Study debunks Amazon rainforest theory

BOSTON, March 16 (UPI) -- A NASA-funded study contradicts a previous U.N. report that the Amazon rainforests thrive during long droughts.

The Boston University study, using NASA satellite data, concluded Amazon rainforests were remarkably unaffected by a once-in-a-century drought in 2005, neither dying nor thriving, contrary to a report by the U.N.'s Intergovernmental Panel on Climate Change.

"We found no big differences in the greenness level of these forests between drought and non-drought years, which suggests that these forests may be more tolerant of droughts than we previously thought," said Arindam Samanta, the study's lead author.

The U.N. panel's report, published in 2007 by the journal Science, claimed the rainforests actually thrive in drought because of more sunshine under cloudless skies, the scientists said. The latest report said that study was flawed and not reproducible.

"This new study brings some clarity to our muddled understanding of how these forests, with their rich source of biodiversity, would fare in the future in the face of twin pressures from logging and changing climate," said Boston University Professor Ranga Myneni.

The research that included Sangram Ganguly of the Bay Area Environmental Research Institute in Sonoma, Calif., appears in the journal Geophysical Research Letters.

Sony asks for healthier concession snacks

LAS VEGAS, March 16 (UPI) -- The head of a major Hollywood studio is asking for healthier snacks at concession stands in addition to candy, popcorn and soda.

In a speech at ShoWest, the nation's largest convention for the movie theater industry, Michael Lynton, the chief executive officer of Sony Pictures Entertainment, said "adding healthier options to your existing menu is the right thing to do for our industry, for audiences and for our country."

Lynton said he was not asking theaters to stop selling popcorn, soda and candy.

"Audiences love them," he said. "I'm just talking about adding some healthier items to what you already sell."

Some healthier snack options could include fresh fruit, fruit cups, apples with dip; veggies with dip; yogurt; granola bars and trail mix; baked chips, apple chips and unbuttered, air-popped popcorn.

Lynton said some people sneak healthy snacks into movie theaters, like a granola bar or a box of raisins, which represents an untapped market for concession stands.

Theater owners should consider taking this step because childhood obesity is an epidemic, it's the responsible thing to do for audiences and society and it's good for their business because it would help families enjoy theaters even more and, by giving them healthier options, more snacks will be purchased, Lynton said.

Reindeer don't use dark-light sun cycles

MANCHESTER, England, March 16 (UPI) -- British and Norwegian scientists say they've discovered arctic reindeer don't use the internal clock that drives daily biological rhythms in other organisms.

University of Manchester Professor Andrew Loudon and biologist Karl-Arne Stokkan of Norway's University of Tromso said in the northern arctic, the sun doesn't set for part of the year and at other times it never appears.

"Our findings imply that evolution has come up with a means of switching off the cellular clockwork," Loudon said. "Such daily clocks may be positively a hindrance in environments where there is no reliable light-dark cycle for much of the year."

In most mammals, Loudon said, the process involves an internal clock that drives hormone levels, in particular melatonin, in a rhythmic 24-hour fashion, even when there is no light-dark cycle.

But, Loudon said, northern arctic reindeer show no natural internal rhythm of melatonin secretion. Instead, hormone levels rise and fall in direct response to light and dark. Such hormone concentrations spike almost as soon as the light goes out, only to dive again when the light again appears.

Although the researchers do not yet know how the hormone concentrations affect the reindeer, they said: "It is attractive to speculate that in reindeer informative melatonin signals … directly entrain a 'circannual clock' that, at least in reindeer, may not involve circadian mechanisms."

Loudon said he suspects similar patterns will be uncovered in other arctic animals.

The study appeared in the March 11 online edition of the journal Current Biology.

Link between obesity and cancer is studied

EDMONTON, Alberta, March 16 (UPI) -- Canadian scientists say they have taken a step toward understanding the correlation between obesity and cancer.

University of Alberta Associate Professor Richard Lamb said he is studying a cell pathway in the human body that regulates cell growth. Lamb and his research group say they've discovered the pathway can be affected by sources not within the cell, specifically amino acid nutrients that are the building blocks of tissue and muscle in the human body.

The scientists say what makes their study interesting is that the amino acids are found to be elevated in obese people, suggesting the signaling pathway, called mTOR, could be hyperactivated by the heightened amino acid nutrients and that could affect how human cells respond to stress and disease.

Lamb said he and his team will now investigate whether cancer cells are aided by the potential hyperactivity of the pathway.

The research appears in the journal Molecular Cell.