Unusual impact craters formed on Mars feature a thin outer deposit that extends many times beyond the typical range of ejecta.

Nadine Barlow, professor of physics and astronomy at Northern Arizona University, calls these craters Low-Aspect-Ratio Layered Ejecta (LARLE) craters, since the ratio of the thickness to the length of the deposit (the aspect ratio) is so small. 

Barlow found the LARLE craters while poring over high-resolution images to update her highly popular catalog of Martian craters. These craters stood out since they displayed this extensive outer deposit beyond the normal ejecta blanket of the crater. "I had to ask, 'What is going on here?' " Barlow said.

A study to see whether narrowing of the veins from the brain to the heart could be a cause of multiple sclerosis has found that the condition is just as prevalent in people without the disease.

The results call into question a controversial theory that MS is associated with a disorder proponents call chronic cerebrospinal venous insufficiency (CCSVI).

A new paper analyzed organizational change in state health-related departments from 1990 to 2009. The researchers discovered that in many cases states kept the same organizational structure in place during the 20-year period, even though consolidating public health departments with Medicaid departments did occur with some frequency.

27 states had housed the two functions together at one point in the 20-year period. And when they did so, the funding allocated to the public health department remained unchanged. The authors conclude that the results help allay concerns that when such mergers occur they automatically lead to cutbacks in jobs.

Eating disorders such as anorexia nervosa and bulimia nervosa are primarily cultural but the search is also on for a biological disposition that would confirm it outside primarily middle-class white girls in developed nations. Eating disorders are found in families but no genetic basis for predisposition has been identified. 

You've seen advertisements for brain training games, apps, and websites that promise to give your mental abilities a boost - even "Baby Einstein" videos for infants make the claim that they will lead to higher intelligence.

A new paper finds that brain training programs might strengthen the ability to hold information but they won't bring any benefits to intelligence, like helping you reason and solve problems.

The cognitive boost claims are based on correlations between working memory capacity (WMC), our ability to keep information either in mind or quickly retrievable, particularly in the presence of distraction, and general fluid intelligence. General fluid intelligence is the ability to infer relationships, do complex reasoning, and solve novel problems.

The early days of Ashkenazi Jews – that is, Jews with more recent ancestry in central and Eastern Europe – are a hot debate topic. It is believed that their ancestors migrated into Europe from Judea in the first century A.D., after the destruction of the Second Temple by the Romans, and that led to some intermarriage with Europeans later on.  

Others have argued that they have a mainly European ancestry, and arose by conversion to Judaism of indigenous Europeans, especially in Italy. While still others have even argued that they were largely assimilated in the North Caucasus during the time of the Khazar Empire, the Turkic people in the Western steppe whose rulers turned to Judaism around of the tenth century AD.

The earliest evidence of a comet entering Earth's atmosphere and exploding has been found. It rained down a shock wave of fire which obliterated every life form in its path, has been found. 

Clouds on Mars look a lot like those on Earth: images of the Martian sky taken by NASA's Opportunity rover depict gauzy, high-altitude wisps, similar to our cirrus clouds.

These clouds likely consist of either carbon dioxide or water-based ice crystals but since we can't sample a Martian cloud yet, it's difficult to know the precise conditions that give rise to them. So researchers have done the next-best thing; they've recreated Mars-like conditions within a three-story-tall cloud chamber in Germany, adjusting the chamber's temperature and relative humidity to match conditions on Mars — essentially forming Martian clouds on Earth.