News

  1. Earth

    Not So Green? Using hydrogen as fuel may hurt environment

    Replacing fossil fuels with clean-burning hydrogen—considered to be a way to reduce globe-warming carbon dioxide—may create a different set of environmental problems, including larger and longer-lasting ozone holes.

    By Sid Perkins
  2. Humans

    Small World After All: Short e-mail chains reach targets worldwide

    A large-scale study of e-mail users has borne out the notion that one person on the planet can reach any other person through a chain of about six social ties.

    By Erica Klarreich
  3. Chemistry

    Amending the Genetic Code: Yeast adds new amino acids to its proteins

    Researchers have created yeast cells that add one of five unnatural amino acids to their natural 20-piece construction set.