Deadly high temps possible in the future
WEST LAFAYETTE, Ind., May 10 (UPI) -- U.S. and Australian scientists say worst-case scenarios for global warming suggest deadly high temperatures for humans might occur in coming centuries.
Purdue University Professor Matthew Huber and University of New South Wales Professor Steven Sherwood say they've calculated the highest tolerable "wet-bulb" temperature and found it could be exceeded for the first time in human history if greenhouse gas emissions are not abated.
Wet-bulb temperature is the equivalent of what is felt when wet skin is exposed to moving air.
Humans and most mammals experience potentially lethal heat stress levels at a wet-bulb temperature above 95 degrees Fahrenheit sustained six hours or more, Huber said.
"Although areas of the world regularly see temperatures above 100 degrees, really high wet-bulb temperatures are rare," Huber said, explaining the hottest areas normally have low humidity, allowing the body to be cooled by perspiration.
But he said a warming of 21-degrees would put half of the world's population in an uninhabitable environment.
"These temperatures haven't been seen during the existence of hominids, but they did occur about 50 million years ago, and it is a legitimate possibility Earth could see such temperatures again," Huber said. "If we consider these worst-case scenarios early enough, perhaps we can do something to address the risk through mitigation or new technological advancements that will allow us to adapt."
The study appears in the Proceedings of the National Academy of Sciences.
NASA: Omega-3 might help reduce bone loss
HOUSTON, May 10 (UPI) -- NASA scientists say they've determined omega-3 fatty acids found in fish oil might help mitigate bone loss that occurs during spaceflight and in osteoporosis.
Researchers at the Johnson Space Center in Houston said their findings could have significant implications for both space travelers and people susceptible to bone loss on Earth.
The research involved studies using cell cultures, ground-based bed rest and data from space shuttle and International Space Station crew members.
In the cell-based studies, scientists found that adding a specific omega-3 fatty acid to cells would inhibit the activation of factors that lead to bone breakdown, specifically nuclear factor kappa B.
In a study of astronauts returning from short-duration shuttle missions, researchers found kappa B activation had increased in blood cells collected at landing, and remained elevated for two weeks.
The ground-based bed rest study determined bed rest simulates some effects of weightlessness, including muscle and bone loss. During the study, higher intake of omega-3 fatty acids was associated with less bone loss.
"These results are very exciting, and provide initial evidence that nutrition may be a key factor in mitigating bone loss in astronauts." said Scott Smith, a NASA nutritionist and one of the paper's authors.
The study that included co-authors Sara Zwart, Duane Pierson, Satish Mehta and the late Steve Gonda appears in the Journal of Bone and Mineral Research.
Voyager 2 has data transmission problem
PASADENA, Calif., May 10 (UPI) -- U.S. space agency engineers say they have shifted the Voyager 2 spacecraft into status data mode while they diagnose a problem with its data formatting.
Officials said status data suggest the spacecraft is healthy, but the source of the issue is a system that formats data to send back to Earth. The change in the return pattern has prevented mission managers from decoding science data.
Space agency scientists said the troubleshooting process is made difficult since it takes nearly 13 hours for signals to reach the spacecraft and nearly 13 hours for signals from Voyager 2 to reach NASA's Deep Space Network on Earth.
The spacecraft was launched in August 1977, about two weeks before its twin spacecraft, Voyager 1. The two spacecraft are the most distant human-made objects, both now at the edge of the heliosphere -- the bubble the sun creates around the solar system. NASA says it expects Voyager 1 to leave the solar system and enter interstellar space during the next five years or so, followed shortly thereafter by Voyager 2.
"Voyager 2's initial mission was a four-year journey to Saturn, but it is still returning data 33 years later," said Ed Stone, Voyager project scientist at the California Institute of Technology in Pasadena.
Voyager 2 is now about 8.6 billion miles from Earth.
Gene's role in atrial fibrillation studied
HOUSTON, May 10 (UPI) -- Texas A&M University scientists say they've identified a gene's role in atrial fibrillation -- a finding they say might lead to new treatments for the malady.
Researchers at the university's Health Science Center said their study was directed at understanding the genes that are important for controlling the normal heart beat rhythm.
"We believe this knowledge will be useful for making medications that can be used to treat atrial fibrillation," said Dr. James Martin, a professor at the center's Institute of Biosciences and Technology.
Atrial fibrillation, is an abnormal heart beat found in about 2.2 million Americans that can lead to clotting and stroke.
In the study, Martin and his colleagues examined a gene called Pitx2, part of a genetic family that's important in embryonic development, including the heart.
They found Pitx2 inhibits the synthesis of other genes, predisposing people to atrial fibrillation. The goal now is to learn why that inhibition occurs.
The study that included Jun Wang, Elzbieta Klysik, Subeena Sood, Dr. Xander Wehrens and Associate Professor Randy Johnson also involved the Baylor College of Medicine.
The findings are reported in the early online edition of the Proceedings of the National Academy of Sciences prior to print.
