Although researchers have known since 1999 that traces of the Ebola virus could remain in semen for months, two papers published in The New England Journal of Medicine today offer more detail about the frightening possibility that survivors of an infection could rekindle outbreaks. One study focuses on nearly 100 men in Sierra Leone who survived the dreaded viral illness, whereas the second one documents a clear case of sexual transmission of Ebola virus.

In the Sierra Leone study, researchers found Ebola viral RNA in semen samples from almost half the 93 men they tested.  The likelihood of finding viral RNA declined as time from disease onset increased: All nine men who were tested 2 to 3 months after they fell ill had evidence of Ebola RNA in their semen, but the researchers  found it in only 26 of 40 men whose infections had started 4 to 6 months earlier and in 11 of 43 men whose infections had started 7 to 9 months earlier. The result from one Ebola patient tested 10 months after disease onset was indeterminate.

Ever since human beings first began climbing the world's tallest mountains, they have struggled with a basic problem: altitude sickness, caused by lower air pressures which affect the ability of our bodies to take up oxygen. 

Or, as actor Jason Clarke says in his role as the climbing guide Rob Hall in the recently released movie, Everest, "Human beings simply aren't built to function at the cruising altitude of a 747." 

Higher temperatures result in Swedish sand lizards laying their eggs earlier, which leads to better fitness and survival in their offspring, according to research published in the open access journal BMC Evolutionary Biology.

The findings indicate that climate change could have positive effects on this population of high-latitude lizard, but the authors warn that climate change is likely to affect a whole suite of traits, in addition to egg-laying date, which together would have an unknown combined effect on survival and reproductive success.

Making predictions about climate variability often means looking to the past to find trends. Now paleoclimate researchers from the University of Missouri have found clues in exposed bedrock alongside an Alabama highway that could help forecast climate variability. In their study, the researchers verified evidence suggesting carbon dioxide decreased significantly at the end of the Ordovician Period, 450 million years ago, preceding an ice age and eventual mass extinction. These results will help climatologists better predict future environmental changes.

The Ordovician geologic period included a climate characterized by high atmospheric carbon dioxide (CO2) levels, warm average temperatures and flourishing life. Near the end of the period, CO2 levels dropped significantly but precisely when and how fast is poorly known. Kenneth MacLeod, a professor in the Department of Geological Sciences in the MU College of Arts and Science, directed a research team studying the climate changes 450 million years ago to better understand the interactions among the biosphere, the oceans, atmospheric CO2 levels, and temperature.

A new study from the team behind NASA's Mars Science Laboratory/Curiosity has confirmed that Mars was once, billions of years ago, capable of storing water in lakes over an extended period of time.

Using data from the Curiosity rover, the team has determined that, long ago, water helped deposit sediment into Gale Crater, where the rover landed more than three years ago. The sediment deposited as layers that formed the foundation for Mount Sharp, the mountain found in the middle of the crater today.

Deep in the jungles of the Yucatan peninsula, residents of the remote Mexican village of La Mancalona are producing clean drinking water using the power of the sun.

For nearly two years now, members of the community, most of whom are subsistence farmers, have operated and maintained a solar-powered water purification system engineered by researchers at MIT.

The system consists of two solar panels that convert sunlight into electricity; these, in turn, power a set of pumps that push water through semiporous membranes in a filtration process called reverse osmosis. The setup purifies both brackish well water and collected rainwater, producing about 1,000 liters of purified water a day for the 450 residents.

Can you imagine a drug that would make it easier to learn a language, sharpen your memory and help those with dementia and Alzheimer’s disease by rewiring the brain and keeping neurons alive?

People with a dementia such as Alzheimer's disease lose their memory when brain cells shrink and die because connections can no longer transfer information.

New Rutgers research published in the Journal Neuroscience found that a drug – RGFP966 – administered to rats made them more attuned to what they were hearing, able to retain and remember more information, and develop new connections that allowed these memories to be transmitted between brain cells.

The revelations that Volkswagen, the world's second largest car manufacturer, had routinely gamed US emissions testing has thrown the spotlight on the environmental and health impact of cars.

While EU member states, such as the UK, open or consider investigations into the beleaguered company, European Commission officials are currently reviewing the executive’s 2011 White Paper for transport, its main policy roadmap for the sector.

Bringing extra impetus to their deliberation is the upcoming UN Climate Change Conference in Paris, international talks aimed at capping global warming.

Many tropical Pacific island nations are struggling to adapt to gradual sea level rise stemming from warming oceans and melting ice caps. Now they may also see much more frequent extreme interannual sea level swings. The culprit is a projected behavioral change of the El Niño phenomenon and its characteristic Pacific wind response, according to recent computer modeling experiments and tide-gauge analysis by scientists Matthew Widlansky and Axel Timmermann at the International Pacific Research Center, University of HawaiÊ»i at Mānoa, and their colleague Wenju Cai at Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Australia.

During El Niño, warm water and high sea levels shift eastward, leaving in their wake low sea levels in the western Pacific. Scientists have already shown that this east-west seesaw is often followed six months to a year later by a similar north-south sea level seesaw with water levels dropping by up to one foot (30 cm) in the Southern Hemisphere. Such sea level drops expose shallow marine ecosystems in South Pacific Islands, causing massive coral die-offs with a foul smelling tide called taimasa (pronounced [kai’ ma’sa]) by Samoans.

If you are struggling with weight gain, you might be surprised to know that your parents had it easier - they could eat more and exercise less, and still avoid obesity, according to a recent study out of York University's Faculty of Health.

"Our study results suggest that if you are 25, you'd have to eat even less and exercise more than those older, to prevent gaining weight," says Professor Jennifer Kuk in the School of Kinesiology and Health Science. "However, it also indicates there may be other specific changes contributing to the rise in obesity beyond just diet and exercise."