Scientists demonstrated that some marine mammals have died from eating fish tainted with a neurotoxic diatom. (p. 20)

Marine iguanas in the Galápagos Islands are the first vertebrates known to reduce their size during a food shortage and then regrow to their original body lengths. (p. 20)

Malaria parasites shift their female-biased production of offspring toward a more evenly balanced sex ratio as an infection proceeds. (p. 21)

A strong electric field can drive tiny particles of a superconductor to bind themselves together into a remarkably sturdy ball. (p. 21)

The chemical glutamate can overwhelm nervous-system cells called oligodendrocytes, adding to the nerve damage caused by wayward immune cells in multiple sclerosis. (p. 22)

The perplexing human tendency to perceive a moon on the horizon as larger than an elevated moon may arise from visual cues indicating that the horizon moon is located much farther away. (p. 22)

The discovery of diamond-crystal seeds on steps in silicon may lead to long-sought, large wafers of pure, single-crystal diamond for electronics and other uses. (p. 23)

The reappearance of a California Indian's preserved brain, held at the Smithsonian Institution since 1917, triggers debate over the ethics of anthropological research and the repatriation process. (p. 24)

Detection of gravitational waves predicted by Einstein's 1916 general theory of relativity may finally occur, thanks to a new generation of laser-based observatories. (p. 26)

Two new studies suggest that galaxies may be surrounded by vast halos of dark matter extending at least 1.5 million light-years from each galaxy's center. (p. 30)

A study of more than 1,000 women who had hysterectomies finds that after the operation, women generally wanted and had sex more often, were more likely to reach orgasm, experienced less vaginal dryness, and were less likely to have pain during sex than was the case before surgery. (p. 31)

Sixth-graders in Italy routinely carry school backpacks that equal, on average, 22 percent of their body weight, a finding researchers link to an earlier report that more than 60 percent of children in this age group had experienced low-back pain more than once. (p. 31)