Researchers announced the discovery of a nearly complete fossil skull, along with jaw fragments and isolated teeth, from the earliest known member of the human evolutionary family, which lived in central Africa between 7 million and 6 million years ago. (p. 19)

Agricultural pollutants may conspire with parasites to cause the epidemic of limb deformity that's sweeping through North America's frog populations. (p. 19)

A new, easily prepared hydrogel material promotes more rapid wound healing in laboratory animals than do conventional dressings. (p. 20)

The sperm of wood mice hook together by the thousands to form high-speed teams racing toward an egg, even though only one of the pack will get the prize. (p. 20)

Some types of bacteria living in seafloor mud can generate enough electricity to power small electronic devices. (p. 21)

Vaccinating an entire city in response to a smallpox terrorist attack would save thousands more lives than would quarantining infected people and vaccinating anyone they contacted. (p. 21)

Astronomers have obtained the first portrait of X-ray emission from a rare, so-called Ic supernova. (p. 22)

In an experiment with implications for bioterrorism, scientists have used poliovirus' widely known genetic sequence to synthesize that virus from DNA and other chemicals. (p. 22)

X-ray outbursts from two different pairs of stars in our Milky Way are providing clues about how the most rapidly rotating stars in the universe got their spin. (p. 24)

Scientists are turning carbon-cage molecules called fullerenes into drug candidates and medical diagnostic tools. (p. 26)

Watermelon is a far better source of the carotenoid lycopene than tomatoes are and at least as well absorbed by the body. (p. 29)

Using ribbons made of organic molecules as minuscule templates, researchers have coaxed a semiconductor material into tiny helical coils. (p. 29)

New insect repellents based on a compound that contributes to the smell of crushed tomato leaves are under development. (p. 29)

Extracts from the berry of the American ginseng plant counter obesity and insulin resistance in mice. (p. 29)

Scientists have found a long-sought enzyme that may be behind nitroglycerin's dilation of blood vessels. (p. 30)

Analyses of fossil leaves provide more evidence that the mass extinctions that wiped out the dinosaurs 65 million years ago were sudden and probably brought about by an extraterrestrial impact. (p. 30)

Planetary scientists have for the first time precisely dated a collision that smashed an asteroid into fragments. (p. 30)