A recently discovered fossil dinosaur heart is more like the heart of birds and mammals than that of crocodiles, providing further evidence that dinosaurs may have been warm-blooded. (p. 260)

The gains in bone health can quickly disappear when people stop taking extra calcium. (p. 260)

Three new studies reveal that Earth's home galaxy indulged in cannibalism to assemble its visible halo, the diffuse distribution of stars that surrounds the dense core and disk of the Milky Way. (p. 261)

Two research teams say they've caught wild animals bluffing, only the second and third examples (outside of primate antics) ever recorded. (p. 262)

Nerve cells seem to package key components of synapses—the specialized complexes than connect the nerve cells—and collectively ship the material to points where these complexes take shape. (p. 262)

Social isolation may promote the development of Alzheimer's disease and other brain ailments among elderly people. (p. 263)

A novel method for measuring tiny amounts of hydrogen-containing impurities allows researchers to determine growth rates along different directions in a quartz crystal. (p. 263)

Bacterial toxin may lead to less painful treatments for diabetes and brain cancer. (p. 266)

Your skin chemicals lure blood-sucking insects to their next meal. (p. 268)

An inexpensive test for two proteins in the blood can indicate whether women with breast cancer that hasn't yet spread to lymph nodes are likely to face such a relapse after surgery. (p. 264)

Estrogen receptors proliferating on tumor cells in women's lungs may account for why women seem more easily affected by the carcinogenic effects of tobacco smoke. (p. 264)

A drug that turns off a gene that blocks the action of chemotherapy in melanoma shows promise against this lethal skin cancer. (p. 264)

Prostate cancer patients who harbor high concentrations of a protein called thymosine beta-15 in their tumors face an increased risk that the cancer will spread. (p. 264)

Scientists studying rats have now developed a medication that wards off chemotherapy-induced baldness. (p. 264)

Fearing that its 9-year-old workhorse, the Compton Gamma Ray Observatory, could plunge uncontrollably through the atmosphere if one more of its gyroscopes fails, NASA has decided to crash the spacecraft into the Pacific Ocean in early June. (p. 271)

An astronomer has formally retracted her claim that she and her colleagues had likely taken the first image of a planet outside the solar system. (p. 271)

Chemists are improving antibacterial fabrics by treating them with compounds that prolong their killing power and add color. (p. 271)

Mechanical stress from constricting muscles could cause airway-lining cells to reproduce, eventually thickening the lining and narrowing the air passage. (p. 271)