News

  1. Earth

    Contraceptive ring could pose risks after its disposal

    Discarded vaginal contraceptive rings could interfere with fishes' reproduction by releasing estrogen into streams.

    By Janet Raloff
  2. Earth

    Snow alga may be sizable carbon sink

    A common microorganism that adds a reddish tinge to some patches of snow may be a significant consumer of planet-warming carbon dioxide.

    By Sid Perkins
  3. Health & Medicine

    Do liver stem cells come from bone marrow?

    Tests of liver tissue from people who've received liver or blood-marrow transplants show that stem cells in bone marrow can populate the liver as liver cells.

    By Nathan Seppa
  4. Materials Science

    Conch yields clues for future materials

    A conch's tough, calcium carbonate shell resists fractures because a protein surrounds the mineral crystals throughout the shell.