Birth order may steer some men toward homosexuality in a process that perhaps begins before birth. (p. 3)

A study of dinosaur eyes finds that Tyrannosaurus rex had very sophisticated vision that may have helped its predatory abilities. (p. 3)

A new type of combustion chamber reduces pollution with less complexity and a safer, more reliable design. (p. 4)

A combination of two enzymes could eventually treat celiac disease, an inherited digestive disorder. (p. 4)

A new test is the first to measure production and clearance of amyloid-beta in the cerebrospinal fluid of people, enabling scientists to track this Alzheimer's disease peptide. (p. 5)

Two banana-shaped arcs of gas and dust face each other within a newly discovered planet-forming disk that surrounds a young, nearby star. (p. 5)

A new study describes the efficient use of fructose toward making a renewable building block for many useful chemicals. (p. 6)

Two natural ingredients in many hair- and skin-care products act like a female sex hormone and can cause abnormal breast development in boys. (p. 6)

A new way to power artificial muscles improves the prospects for making lifelike humanoid robots and prosthetic limbs. (p. 8)

While no drug or lab test is approved to treat or diagnose chronic fatigue syndrome, new research into the biology of the disorder may begin to shed light on the problem. (p. 10)

About 13 billion years after its birth, our galaxy is still packing on the stars. (p. 12)

A 4,500-year-old human skeleton found in Mexico represents the earliest instance in the Americas of intentionally modified teeth, apparently to create space for a ceremonial mouthpiece. (p. 13)

Contrary to a report published last year, cells that circulate in a female mammal's blood don't seem to restock its egg supplies. (p. 13)

Babies exposed in the first trimester of their mother's pregnancy to blood pressure drugs called ACE inhibitors are at an increased risk of birth defects. (p. 13)

Allowing doctors-in-training who are on call to hand off to another doctor the pager that summons them to the next patient increases the amount of sleep they get and reduces their fatigue. (p. 13)

A nanoparticle-laden, pressure-detecting membrane feels textures with about the same sensitivity as human skin. (p. 14)

The cells responsible for hearing in mammals may be capable of regeneration, just as those of birds and other vertebrates are. (p. 14)

Researchers have developed a smart petri dish that signals cell death with intense light. (p. 14)

To prevent unauthorized picture taking, an automated antispy system spots digital cameras and zaps them with confounding flashes of light. (p. 14)

(p. 15)