Environmental pollutants such as dioxins affect human health. It now seems that dioxins exert their effect by forming atypical enzyme complexes that mediate the breakdown of steroid-hormone receptors.

The conclusion that the primary divergences of the modern groups of mammals occurred in the mid-Cretaceous requires fresh thinking about this facet of evolutionary history — especially in ecological terms.

Electrons in one particular solid phase of plutonium are complex characters: while bound to atoms, in a quantum-mechanical mixture of two different valence states, they also roam freely throughout the crystal.