Cirrus clouds, the thin wisps of vapor that coalesce in the upper layers of the troposphere and trail across the sky, often more than 10 miles above the Earth's surface, influence our global climate, cooling the planet by reflecting incoming solar radiation and warming it by trapping outgoing heat.

Understanding the mechanisms by which these clouds form would help scientists make accurate predictions about future climate patterns.

Water found on the moon and Earth came from small meteorites called carbonaceous chondrites in the first 100 million years or so after the solar system formed, according to researchers who found evidence in samples of moon dust returned by lunar crews of Apollo 15 and 17.

Comets did not deliver the molecules, they conclude in their Science Express article.

The discovery's telltale sign is found in the ratio of an isotopic form of hydrogen, deuterium, to standard hydrogen. The ratio in the Earth's water and in water from specks of volcanic glass trapped in crystals within moon dust match the ratio found in the chondrites. The proportions are far different from those in comet water. 

While school-age models of atomic nuclei show them as being spherical, like a basketball, they are more like the shape of a football. 

Yet for some particular combinations of protons and neutrons, nuclei can also assume very asymmetric shapes, like a pear, where there is more mass at one end of the nucleus than the other. 

Men who experience sexual harassment are far more likely than women to induce vomiting and take laxatives and diuretics - purging - in an attempt to control their weight, according to a new psychology paper.

The African clawed frog (Xenopus laevis) and Budgett's frog (Lepidobatrachus laevis) differ in diet and last shared a common ancestor about 110 million years ago but what they were found to have in common could help researchers on the path to prevention of intestinal birth defects. 

Like most tadpoles, Xenopus exist primarily on a diet of algae, and their long, simple digestive tracts are not able to process insects or proteins until they become adult frogs. Budgett's is an aggressive species of frog which is carnivorous – and cannibalistic – in the tadpole stage.

During the late Pleistocene, which ended about 12,000 years ago, a remarkably diverse assemblage of large-bodied mammals inhabited the "mammoth steppe," a cold and dry environment that extended from western Europe through northern Asia and across the Bering land bridge to the Yukon.

Of the large predators - wolves, bears, and big cats - only the wolves and bears were able to maintain their ranges well after the end of the last ice age and a new study suggests that dietary flexibility may have been an important factor giving wolves and bears an edge over saber-toothed cats and cave lions.