Many animals change sex at some point in their lives, often after reaching a certain size. Snails called slipper limpets begin life as males, and become female as they grow. A new Smithsonian study shows that when two males are kept together and can touch one another, the larger one changes to female sooner, and the smaller one later. Contact, rather than chemicals released into the water, is necessary for the effect.

"I was blown away by this result," said co-author Rachel Collin, staff scientist at the Smithsonian Tropical Research Institute (STRI). "I fully expected that the snails would use waterborne cues to see their world."

Forests help remove carbon dioxide from the atmosphere by storing it in trees, but a sizeable amount of the greenhouse gas actually escapes through the soil and into rivers and streams.

That's the main finding of a paper to appear Monday in the Proceedings of the National Academy of Sciences. It's the first study to comprehensively look at how carbon moves in freshwater across the entire U.S.

The researchers found that across the country, the ability of forests to store carbon is not as robust once freshwater is factored into the equation. They hope to introduce this as an important concept to consider when modeling how much carbon is stored in terrestrial landscapes.

When it comes to accurately identifying a criminal suspect, it makes a difference how sure an eyewitness is, finds a study led by a memory expert at the University of California, San Diego. The American justice system should take note of eyewitness confidence, but only at the time of the initial identification and not at a later date in court. Working with victims and bystanders of actual robberies, the study also finds in favor of the traditional lineup procedure that presents suspects at the same time as known innocents, instead of individually.

Scientists at the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) have developed a novel electrolyte for use in solid-state lithium batteries that overcomes many of the problems that plague other solid electrolytes while also showing signs of being compatible with next-generation cathodes.

Berkeley Lab battery scientist Nitash Balsara, working with collaborator Joseph DeSimone of the University of North Carolina at Chapel Hill, came up with a highly conductive hybrid electrolyte, combining the two primary types of solid electrolytes--polymer and glass.

The brains of children who suffer clinical depression as preschoolers develop abnormally, compared with the brains of preschoolers unaffected by the disorder, according to new research at Washington University School of Medicine in St. Louis.

Their gray matter -- tissue that connects brain cells and carries signals between those cells and is involved in seeing, hearing, memory, decision-making and emotion -- is lower in volume and thinner in the cortex, a part of the brain important in the processing of emotions.

The new study is published Dec. 16 in JAMA Psychiatry.

Ice core records are rich archives of the climate history during glacial-interglacial cycles over timescales of up to ~800 kyr before the current age. In ice core studies, the accurate and precise dating of the core samples is a central issue that must be investigated to better constrain the timing, sequence, and duration of past climatic events.

It may be your liver (and not your better judgement) that keeps you away from excess sweets this holiday season. Two independent research groups have found the first evidence of a liver-derived hormone that specifically regulates intake of sugars and alcohol in mice. One of the studies also found that the same hormone suppresses the consumption of sweets in primates.

"A lot of work has examined the central mechanisms regulating sugar-seeking behavior, but the post-ingestive mechanisms regulating sugar appetite are poorly understood," says Matthew Potthoff of the University of Iowa, a senior author on one of the papers.

Australian scientists have for the first time revealed how malaria parasites cause an inflammatory reaction that sabotages our body's ability to protect itself against the disease.

The discovery opens up the possibility of improving new or existing malaria vaccines by boosting key immune cells needed for long-lasting immunity. This could even include vaccines that have previously been ineffective in clinical trials.

Researchers from Melbourne's Walter and Eliza Hall Institute discovered that the same inflammatory molecules that drive the immune response in clinical and severe malaria also prevent the body from developing protective antibodies against the parasite.

While the rapid emergence of antibiotic-resistant bacteria has prompted the medical community and media to educate the public to the dangers of misusing and overusing antibiotics but there may be more to the problem than medications - an ecologist is finding a way to blame nuclear research from the 1950s, good timing as environmentalists have declared open war on 'green' scientists who support nuclear energy as the most viable alternative to fossil fuels.

Using mathematical models, scientists have 'looked' into the interior of super-Earths and discovered that they may contain compounds that are forbidden by the classical rules of chemistry -- these substances may increase the heat transfer rate and strengthen the magnetic field on these planets. The findings have been presented in a paper published in the journal Scientific Reports.

The authors of the paper are a group of researchers from MIPT led by Artem Oganov, a professor of the Skolkovo Institute of Science and Technology and the head of the MIPT Laboratory of Computer Design. In a previous study, Oganov and his colleagues used an algorithm created by Oganov called USPEX to identify new compounds of sodium and chlorine, as well as other exotic substances.