Feature Article

Hairless mice that ingested arsenite in drinking water exhibited more than a 5-fold enhancement of ultraviolet radiation (UVR) carcinogenesis, whereas arsenite alone was carcinogenically inactive. Dietary organoselenium blocked the cancer enhancement effect of arsenic but not cancer induction by UVR.

Biofuels are being promoted as energy sources that could reduce both dependence on imported oil and fossil fuel emissions. Currently, a large percentage of biofuels are produced from food crops, a situation that some experts say is leading to food insecurity around the world.

Biofuels are held up as a relatively easy solution to the twin problems of petroleum dependence and carbon emissions. But new research suggests that fuels such as corn-based ethanol may cause as many problems as they solve.

Energy policies are in transition worldwide based on a convergence of factors including static oil production coupled with increased demand, a desire for energy independence, and growing awareness of climate change. Making energy choices that improve human health, the environment, and economic development is possible if we understand the complex interplay between systems for energy delivery and sustainable, healthy human environments. (Editorial)

Martin Kennedy and colleagues searched the Australian outback for clues to the transition out of Snowball Earth. The answer, as it turns out, was much closer to home.

There has been a strong disagreement between model predictions of troposphere warming and observations of temperature trends from radiosondes and satellites. However, when tropospheric temperature reconstructions are generated from thermal-wind measurements and the thermal-wind equation for 1970