The armored shells of some marine mollusks have evolved to satisfy two conflicting design requirements, protection and sight, a new study shows.

Kids and teens who take medications like Ritalin to treat attention-deficit hyperactivity disorder are also twice as likely to be physically or emotionally bullied by peers. At even higher risk were middle and high school students who sold or shared their medications--those kids were four-and-a-half times likelier to be victimized by peers.

The main findings are the same for both sexes, said the study's first author, Quyen Epstein-Ngo, research assistant professor in gender studies at the University of Michigan. 

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.