Traces of drugs, excreted by people and livestock, pollute surface and ground waters in the United States, as had already been confirmed in Europe. (p. 212)

Researchers who isolated a sample of Neandertal mitochondrial DNA say that it provides no evidence that Neandertals contributed to modern human evolution. (p. 213)

Two new fruit fly lines—with females that die on cue—could lead to changes in pest control. (p. 213)

The alpha-thujone in absinthe—Vincent Van Gogh's favorite drink—blocks brain receptors for a natural inhibitor of nerve impulses, causing brain cells to fire uncontrollably. (p. 214)

White blood cells injected into patients with pancreatic tumors incite an immune response that blunts the cancer in some patients and extends survival. (p. 214)

NASA's two most recent missions to Mars failed because they were underfunded, managed by inexperienced people, and insufficiently tested, according to a report released March 28. (p. 215)

An iceberg about the size of Connecticut recently split off from the Ross Ice Shelf in Antarctica. (p. 215)

The U.S. Mint performed some neat tricks to make a golden dollar. (p. 216)

Astronomers pass a milestone in the search for new worlds. (p. 220)

The latest inventory of life in the United States has turned up an extra 100,000 species of plants, animals, and fungi. (p. 219)

Field studies of three-spined stickleback fish dash a textbook example of the theory of how one species can take on a competitor's characteristics. (p. 219)

Three gravitationally interacting bodies of equal mass can, according to precise calculations, trace out a figure-eight-shape orbit in space. (p. 219)

A new definition of random packing allows a more consistent and mathematically precise approach to characterizing disordered arrangements of identical spheres. (p. 219)

A 95-million-year-old fossil snake with legs may be an advanced big-mouthed snake, not a primitive ancestor. (p. 223)

The bones of six carnivorous dinosaurs discovered in a fossil bed in Patagonia may indicate that big, meat-eating dinosaurs were social creatures. (p. 223)

A new theory and a simple test with cornstarch and water may help explain the polygonal geometry of rock columns in the Devil's Postpile in California and elsewhere. (p. 223)

Atoms on the surface of carbon nanotubes appear to mesh when tubes roll across a graphite surface, making the tubes possible atomic-scale gears, which have been long-sought in nanotechnology. (p. 223)