The unusually invasive strain of seaweed that has been smothering coastal areas of the Mediterranean has shown up in a California lagoon, the first sighting of this ecologically devastating alga in the Americas. (p. 36)

Transplants using bioengineered corneal stem cells grown on an amniotic membrane can vastly improve vision in people who are nearly blind because of damaged corneas. (p. 36)

Modern technologies reveal than an ancient method of engraving tough quartz in Mesopotamia was adopted some 1,500 years later than scholars had thought. (p. 37)

A substantial minority of people suffering from mental ailments seek out alternative treatments, such as herbal medicines and nutritional regimens, usually without telling their physicians. (p. 37)

Turning a liability into an asset, a new technique for passing information through optical fibers increases the data flow by exploiting the very trait that has long held that flow back. (p. 38)

A vaccine intended to slow or prevent the devastation of Alzheimer's disease appears promising, according to preliminary tests in people. (p. 38)

The massive extinctions that came at the end of the Permian period could have occurred within a mere 8,000 years, which suggests a catastrophic cause for the die-offs. (p. 39)

An ambitious test of group selection considers whether natural selection can act on whole ecosystems as evolutionary units. (p. 39)

Scientists dive deep to learn how the sea circulates. (p. 42)

Fresh approaches may cut back greenhouse-gas emissions. (p. 45)

A survey of painted turtles that perished while trying to cross a highway suggests that the freshwater species need more dry land than expected. (p. 40)

Hunting and no-hunting zones allow a rare test of the much-debated proposal that big carnivores shape their ecosystems from the top down. (p. 40)

A medication combining the drug prasterone and hormone dehydroepiandrosterone, or DHEA, stabilizes or improves symptoms of lupus. (p. 40)

A gene linked to a form of muscular dystrophy also causes a disease that deposits fat unevenly after puberty. (p. 40)

Insomnia is associated with increases in stress hormones, boosts that persist all day and night. (p. 40)

For scurrying upside down on smooth ceilings and other gravity-defying feats, lizards known as geckos may exploit intermolecular forces between the surface and billions of tiny stalks under their toes. (p. 47)

An elaborate, new equation that yields more accurate values for nitrogen's properties might have a multimillion-dollar impact in the cryogenic fluids industry. (p. 47)