Pedestrian wheelchair users in the US are a third more likely to be killed in road traffic collisions than the general public, and men's risk is five times higher than women's, according to a paper in BMJ Open.

AUSTIN, Texas -- Scientists have solved a longstanding mystery about how some fish seem to disappear from predators in the open waters of the ocean, a discovery that could help materials scientists and military technologists create more effective methods of ocean camouflage.

In a paper published this week in Science, a team led by researchers at The University of Texas at Austin reports that certain fish use microscopic structures called platelets in their skin cells to reflect polarized light, which allows the fish to seemingly disappear from their predators.

Polarized light is made up of light waves all traveling in the same plane, such as the bright glare you sometimes see when sunlight reflects off the surface of water.

Stem cell research led by the Babraham Institute has uncovered key new knowledge about how placental stem cells switch between maintaining a stem cell identity to setting off down the route to becoming specialised cell types.

The newly sequenced genomes of two marine worms shed light on the 570 million-year evolution of gills into the human ability to bite, chew, swallow and speak.

The draft genome sequences (doi:10.1038/nature16150) of two species of acorn worm, which live in U-shaped burrows in shallow, brackish water, are the first genomes of hemichordates, which retain similarities to the first animals to evolve pharyngeal or "gill" slits. Those ancestors eventually gave rise to chordates: animals with backbones and hollow nerve cords, like humans and other vertebrates.

Health experts at Johns Hopkins Medicine are calling on lawmakers and regulators to close loopholes in the Orphan Drug Act they claim give drug companies millions of dollars in unintended and misplaced subsidies and tax breaks and fuel skyrocketing medication costs.

In a commentary published Nov. 19 in the American Journal of Clinical Oncology, the authors argue that pharmaceutical companies are exploiting gaps in the law by claiming "orphan" status--a designation meant to encourage the development of drugs for rare diseases that affect fewer than 200,000 people in the United States. Yet many of these drugs, the authors say, end up being marketed for other, more common conditions, generating billions in profits.

Sex will make for a happy couple, according to social psychologists, and you don't even need to do it all that often.

COLUMBUS, Ohio -Women drinking and eating moderate amounts of caffeine during pregnancy should be reassured that they are not harming their child's intelligence, according to a study from The Research Institute at Nationwide Children's Hospital that was published in the American Journal of Epidemiology. The research, one of the first studies to focus on how in utero caffeine exposure affects a child's future intelligence (IQ) and behavior later in childhood, found caffeine did not lead to a reduced IQ or increased behavioral problems.

Exercising, meditating, scouring self-help books... we go out of our way to be happy, but do we really know what happiness is?

Wataru Sato and his team at Kyoto University have found an answer from a neurological perspective. Overall happiness, according to their study, is a combination of happy emotions and satisfaction of life coming together in the precuneus, a region in the medial parietal lobe that becomes active when experiencing consciousness.

A paper in the Canadian Journal of Cardiology warns that the use of unvalidated natural "medicine" may lead to severe poisoning.

A 45-year-old Chinese woman was diagnosed with a severe heart-rhythm disorder, bidirectional ventricular tachycardia (BVT), associated with aconitine poisoning. BVT is a rare form of tachycardia (characterized by a resting heart rate over 100 beats per minute) and a distinct pattern of ECG waves on presentation.

Aspirin has been linked to a decreased risk of colorectal cancer but the risk of side effects, including in some cases severe gastrointestinal bleeding, make it necessary to better understand the mechanisms by which aspirin acts before recommending it as a preventative.