Vol. 164 No. #3
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More Stories from the July 19, 2003 issue

  1. Anthropology

    Lucy’s kind takes humanlike turn

    A new analysis of fossils from a more than 3-million-year-old species in the human evolutionary family reveals that the males were only moderately larger than the females, a finding that has implications for ancient social behavior.

  2. Chemistry

    An inexpensive catalyst generates hydrogen

    A new, inexpensive catalyst could make hydrogen generation cleaner.

  3. Health & Medicine

    Viral protein could help liver therapy

    Researchers have developed a method of delivering gene therapies to targeted cells that makes use of viral proteins rather than whole virus particles.

  4. Materials Science

    Gas sensor uses nanotube parts

    New sensors use carbon nanotubes to analyze gas.

  5. Astronomy

    Revved-up antics of a pulsar jet

    Flailing like an out-of-control fire hose, a mammoth jet of charged particles gushing from a collapsed star is varying its shape and brightness more rapidly than any other jet known in the heavens.

  6. Tech

    Counting calories on the road

    People are programmed to spend about the same number of calories per day—roughly the energy of one hot dog—on daily travel, according to new analysis of British transportation statistics.

  7. Plants

    Stout Potatoes: Armed with a new gene, spuds fend off blight

    Splicing a gene from a blight-resistant wild potato into varieties used for consumption could lead to blight immunity for all spuds.

  8. Where’s Poppa? Absent dads linked to early sex by daughters

    Long-term studies conducted in the United States and New Zealand indicate that girls are particularly likely to engage in sexual activity before age 16 and to get pregnant as teenagers if they grew up in families without a father present.

  9. Health & Medicine

    Split Ends: Cancers follow shrinkage of chromosomes’ tips

    Genetic tabs called telomeres, which normally protect the ends of chromosomes, become undersized in many tissues that later turn cancerous, new studies in people show.

  10. Earth

    Protective Blanket: Atmosphere blocks many small stony asteroids

    A new computer model that more realistically simulates the aerodynamic forces on an object as it passes through Earth’s atmosphere suggests that the thin layer of air is an even better shield than previously thought.

  11. Animals

    City Song: Birds sing higher near urban traffic

    Birds in noisier city spots tend to sing at a higher pitch than do members of the same species in quieter neighborhoods.

  12. Materials Science

    Tiny Labs: Polymers on silicon chip catch, release proteins

    In a step toward a new laboratory-on-a-chip technology, researchers have grown a dense polymer film on a silicon wafer that takes up and releases proteins on command.

  13. Health & Medicine

    Metal’s Mayhem: Cadmium mimics estrogen’s effects, thwarts DNA repair

    Cadmium causes endocrine disruption by mimicking estrogen in rats and also thwarts routine DNA repair, causing mutations, two studies show.

  14. Down the Tubes: Amino acid proves key to plant reproduction

    An amino acid that human brain cells communicate with also has a role in plant sex.

  15. Astronomy

    Supernova Spectacular

    Studying starburst galaxies, relatively nearby galaxies that are undergoing a tremendous rate of star formation, may reveal how elliptical galaxies arose and black holes grew in the early universe.

  16. Paleontology

    Learning from the Present

    New field studies of unfossilized bones, as well as databases full of information about current fossil excavations and previous fossil finds, are providing insights into how complete—or incomplete—Earth's fossil record may be.