Special issue on sleep (p. 16)

Brain studies may reveal the purpose of a behavior both basic and mystifying (p. 16)

Researchers inch closer to causes, cures for insomnia, narcolepsy (p. 24)

Getting too little sleep can impair body and brain and could even be deadly (p. 28)

(p. 23)

A new analysis suggests that ancient seed plants made a version of the fossilized resin credited to more modern relatives (p. 5)

Scientists have uncovered a feather-laden, peacock-sized dinosaur that predates the oldest known bird. (p. 8)

Paleontologists in Bristol, England, at the annual meeting of the Society of Vertebrate Paleontology report on fish fossils in Wyoming, the loss of Australia’s megafauna and the smallest dinosaur tracks. (p. 8)

African hominid fossils, including a partial skeleton, reveal a surprising mix of features suitable for upright walking and tree climbing 4.4 million years ago. (p. 9)

The moon isn’t bone-dry: Its surface and interior contain an abundance of water, new studies reveal. (p. 10)

MESSENGER flew past Mercury for a third time on September 29. The spacecraft's mission will continue, with MESSENGER due to settle into a yearlong orbit around Mercury in March 2011. (p. 10)

Sleep deprivation leads to more Alzheimer’s disease plaques in the brains of genetically susceptible mice. (p. 11)

Fatty tissue may provide a safe haven for cancerous cells to linger, according to a study of mice with leukemia. (p. 11)

A team finds “spooky action at a distance” in superconductors big enough to be seen with the naked eye. (p. 12)

New bonding suggests scientists may need to rethink heavy metal chemistry. (p. 13)

Study finds how proteins self assemble in the cells of Loligo squid to reflect different wavelengths of light (p. 13)

Charles K. Kao wins for discoveries enabling fiber-optic communication, and Willard S. Boyle and George E. Smith win for inventing the charge-coupled device (p. 14)

Three scientists share the Nobel Prize in Physiology or Medicine for the discovery of telomeres, which protect the ends of chromosomes, and the enzyme telomerase, which adds the structures to the ends of chromosomes. (p. 14)

Ada Yonath, Thomas Steitz and Venkatraman Ramakrishnan will share the prize for unmasking the structure of the ribosome. (p. 14)

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Review by Rachel Zelkowitz (p. 35)

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A Harvard Medical School physician and sleep researcher says rules should be changed to make sure physicians-in-training get the sleep they need. (p. 36)