Scientists have found 5.2- to 5.8-million-year-old fossils in Ethiopia that represent the earliest known members of the human evolutionary family. (p. 20)

The discovery of a disparity in decays of subatomic particles known as B mesons and anti-B mesons sheds light on how matter and antimatter differ but deepens the mystery of why matter predominates in the universe today. (p. 20)

The discovery of a new type of hydrothermal vent system on an undersea mountain in the Atlantic Ocean suggests that submarine hydrothermal activity may be much more widespread than previously thought. (p. 21)

Researchers have created new coatings that break down toxins and keep mirrors from fogging when the materials are exposed to visible light. (p. 22)

Scientists have discovered a molecular clock that keeps the circulatory system in sync with the rest of the body, and they show it's regulated by vitamin A. (p. 22)

Tests for genetic variations of a key protein on platelets, the cell-like blood components that form clots, and their propensity to clump could help physicians determine optimal medication for heart disease patients. (p. 22)

The side-effects of radiation therapy may result from initial damage to blood vessels. (p. 23)

A test of starling's tails in a wind tunnel suggests that the standard practice of extrapolating bird tail aerodynamics from delta-wing aircraft may be a mistake. (p. 23)

A new model that includes a forest's effect on regional climate shows that the Amazon rainforest could disappear in the next three decades, much more rapidly than previously expected. (p. 24)

A new analysis of water quality downstream of Atlanta shows that some pollutants from the city are still detectable in the river more than 500 kilometers away. (p. 24)

If a nuclear explosion were set off in a cavity of the right size and shape, even a moderate-sized nuclear bomb might appear at long distances to be no bigger than a routine explosion used in mining. (p. 25)

Bacteria find strength in numbers as members of huge, mucous-covered communities called biofilms that can stall, equip, and initiate fierce infections. (p. 28)

Lack of sleep makes healthy adults somewhat resistant to the effects of the hormone insulin, suggesting it could predispose people toward type II, or adult-onset, diabetes. (p. 31)

Insulin injections failed to prevent type I, or juvenile-onset, diabetes from developing in children and young adults predisposed to the disease. (p. 31)

People with the skin disorder psoriasis respond well to infliximab, a drug normally given to arthritis patients. (p. 31)

Marijuana seems to heighten the risk of heart attack in some people during the hour after which it is smoked. (p. 31)