Unusually carbon-rich rocks found in eastern South Africa may push back the evidence of life on land to 2.6 billion years ago, more than twice the current age of indisputably terrestrial organisms. (p. 356)

Because naked mole rats exhibit permanent physical traits that distinguish certain castes of a colony, they belong to the same grouping as so-called eusocial insects such as bees, ants, wasps, and termites. (p. 356)

A new theorem may lead to a proof of Catalan's conjecture, a venerable problem in number theory concerning consecutive powers of whole numbers. (p. 357)

New evidence from lunar meteorites suggests that debris bombarded the moon some 3.9 billion years ago, about the same time that life may have formed on Earth. (p. 357)

People who practice a task that demands quick visual processing perform it better on ensuing trials if they are first allowed to get some sleep. (p. 358)

A combination of a DNA vaccine and a vaccine based on a genetically modified common cold virus enables monkeys to resist Ebola virus, the first evidence that an Ebola vaccine works in primates. (p. 358)

A parasitic fly introduced to fight gypsy moths starting in 1906 may be an overlooked factor in the declines of giant silk moths. (p. 359)

Electrons ricocheting through a crystal now make it possible for scientists to discern shifts in crystal lattices as small as a hundredth of an atom's width. (p. 359)

Push a button and she turns her head. But can she turn his? (p. 362)

Striving for designer substances that build themselves from individual molecules. (p. 364)

Human skin and scalp tissue may provide a source of neural stem cells. (p. 360)

Rodents exposed to massive amounts of the pesticide rotenone develop a condition similar to Parkinson's disease. (p. 360)

An antibiotic that binds copper and zinc may prevent brain deposits that cause Alzheimer's disease. (p. 360)

A lack of Vitamin A may cause learning and memory problems, albeit potentially reversible ones. (p. 360)

Drugs that lower cholesterol benefit patients who have just had a heart attack or chest pains, regardless of the patient's initial cholesterol levels. (p. 366)

A small study of young women already at high risk of having a heart attack suggests that heart attacks are most frequent when estrogen levels are low, soon after a woman's period begins. (p. 366)

Unusually heavy meals boost a person's chance of developing a heart attack, at least among those people who already have risk factors for heart disease. (p. 366)

Drinking black tea makes a person's blood vessels dilate more easily, which may explain why drinking tea can protect against heart disease. (p. 366)

A small study in mice suggests that inhaling nitric oxide may protect against tissue damage after a heart attack. (p. 366)