The exoplanet GJ 436b has left scientists confused after defying their assumptions about the composition of its atmosphere.

Neptune-sized planets as hot as 800 Kelvin -- about 1,000 degrees Fahrenheit -- should contain high levels of methane and very little carbon monoxide. Instead, the researchers found 7,000 times less methane than expected and plenty of carbon monoxide.

Using NASA's Spitzer Space Telescope, researchers measured the dimming of light as GJ 436b passed behind its star and re-emerged. The difference in the two light levels -- measured six times at different infrared wavelengths -- represents the light emitted by the planet itself.

A team of virologists have discovered important details about a genetic mechanism pathogenic viruses use to evade the immune systems of their hosts. They say their results could point the way to new treatments that use the viruses' own trick against them. The research is detailed in Cell Host and Microbe.

The mechanism is based on the production of short RNA molecules (microRNAs) by the virus. RNA is chemically related to the genetic material DNA, and full-length RNA copies of gene sequences specify the structures of all cell proteins. MicroRNAs (miRNAs), on the other hand, play a crucial role in regulating gene expression.

Health Mullahs everywhere have a brand new set of statistics to push when they lobby the government for more tobacco regulations. A new study in Revista Española de Cardiología suggests that active and former smokers are likely fatter than non-smokers.

The authors of the study say their results confirm that nicotine addiction is not an effective way of to prevent obesity.

Researchers followed 7565 college students over a four-year period. After adjusting for age, sex, initial BMI and lifestyle, weight gain in people who stopped smoking during the study was higher the more cigarettes they smoked a day when the investigation began. Those who continued smoking also gained more weight during this period than the non-smokers.

Researchers studying the differential expression of microRNA say they may have discovered a way to treat autism by reversing the effects of the disease.

Taken together with recently published research regarding “DNA tagging” by methylation, they say their new study in Genome medicine illustrates two different “epigenetic” mechanisms controlling gene activity in autism that lie beyond genetic mutations. While methylation inhibits gene expression at the level of DNA, microRNA inhibits at the level of RNA.

MicroRNA are snippets of RNA, each of which can inhibit the expression of hundreds to more than a thousand genes. The effects of microRNA are also reversible by treatment with complementary “anti-sense” RNA.

Scientists studying the effects of particulate matter on cloud cover in the Amazon say increasing air pollution could have serious consequences for local weather patterns, rainfall and thunderstorms.

The results, published in Geophysical Research Letters, could be used by climate scientists trying to understand the impact of pollution on global weather patterns, the author says.

Researchers demonstrated how pollution's effects on cloud development could negatively impact our environment. While low levels of particulate matter actually help the development of thunderstorms, the reverse is true once a certain concentration is reached ― the particles then inhibit the formation of clouds and thunderstorms.

Osteoporosis is a risk factor for hip fractures, and a study published in BMC Research Notes has found that martial arts training is a suitable way to teach seniors with osteoporosis how to fall down safely, avoiding injury.

Working with six healthy adults, scientists measured the force of their falls and compared it to known information about the amount of impact a patient with osteoporosis could withstand. The falls taught in this study all involved turning a fall into a rolling movement by bending and twisting the trunk and neck, and researchers believe it is possible for older people to learn these impact-reducing techniques.