Random Samples

Science  06 Jun 2003:
Vol. 300, Issue 5625, pp. 1500
  1. Sticking With the Gecko

    A team at the University of Manchester, U.K., says it has succeeded in creating a powerful, reusable adhesive tape inspired by the sticky feet of the gecko, the wall-scrambling lizard.

    Close-up of bottom of gecko foot.

    CREDIT: M. MOFFETT, FROM K. AUTUMN ET AL., PNAS (2002)

    Physicist Andre Geim says the feat is based on the principle that almost any submicrometer object—whether a speck of dust or the tip of a single gecko foot hair—will stick to a solid surface because of the weak intermolecular (van der Waals) forces between the two objects. The forces are tiny—just 1/100 billionths of a Newton. (A Newton is 100 grams.) But a dense array of billions of microscopic plastic pillars on Geim's “gecko tape” make a bond so strong that just a palm-sized section would be enough to hang a man from the ceiling, the scientists calculate. The plastic tape itself is flexible enough to allow the pillars to stick to uneven surfaces without clumping, they report in the July issue of Nature Materials.

    Bob Full, an integrative biologist at the University of California, Berkeley, who measured the strength of real gecko foot hairs in 2000, says that “uses are nearly unlimited” for a gecko tape: “In addition to a general adhesive, it can be used to move computer chips in a vacuum, pick up small fibers, and design novel bandages.”

  2. Boxgrove Secure

    Boxgrove, the site of the oldest human fossil ever found in the United Kingdom, has been rescued from reburial. Last month, English Heritage, a quasi-governmental organization, bought the 8-hectare quarry site, near England's Sussex coast, for $164,000 from Hanson Aggregates, a British company that extracts granite, sand, and quartz.

    Artist's rendering of Boxgrove settlement 500,000 years ago.

    CREDIT: PETER DUNN

    In 1993, Boxgrove—which has been under excavation since the 1970s—yielded a 500,000-year-old shinbone from stocky hominid Homo heidelbergensis, thought by many to be an ancestor of the Neandertals. Researchers also found hominid teeth and hundreds of stone axes that were used to butcher horses, rhinoceri, bison, and deer (Science, 2 March 2001, p. 1722). The complex hominid activities revealed at the site—which used to be a beach on the English Channel—have “transformed the way we think about our earliest ancestors,” says University of Southampton archaeologist Clive Gamble.

    Under environment and safety laws, however, the quarry was due to be filled in, making “future excavation work impossible,” notes Mark Roberts of London's Institute of Archaeology, director of the Boxgrove excavations. With the purchase, he is now planning a new round of “large-scale excavations” over the next 10 to 15 years.

  3. Speed of Thought

    A bit of procrastination may land a laser physicist a coveted science-fiction writing prize. Kenneth Wharton, an assistant professor at San Jose State University in California, is a finalist for this year's John W. Campbell Memorial Award for the Best New Writer, which will be bestowed by a vote of fans attending the annual World Science Fiction Convention this summer in Toronto.

    CREDITS: KENNETH WHARTON

    Wharton, 33, became a fiction writer in 1996 while struggling to complete his Ph.D. thesis at the University of California, Los Angeles. A friend had asked for some far-out physics concepts for a screenplay, but Wharton decided to keep his best ideas to himself. For the next few years, he juggled both novel and thesis, earning his degree in 1998 and publishing Divine Intervention (Ace Books) in 2001. It's a 400-page book that explores what happens when newcomers from Earth arrive at a 150-year-old human colony on a distant planet. He's also published a half-dozen short stories that have solidified his reputation as a “hard” science-fiction writer: someone willing to bend but not break the laws of physics to spin a good yarn.

    Wharton won't know until August if he's beat out four others for a prize that has helped authors such as Jerry Pournelle and Orson Scott Card carve out lucrative careers. Wharton's expectations are lower. “So far, I've only made about a month's salary out of this,” he says. And students who buy his book, he adds, “are usually the ones angling for a better grade.”

  4. In The Courts

    Shoveled out. Buddha Rashmi Mani has been removed as leader of a controversial excavation at a site in north India that many Hindus believe to be the birthplace of Lord Ram. Mani, a veteran of the Archaeological Survey of India (ASI), was bumped 22 May by the Uttar Pradesh state court in the midst of the team's search for the ruins of an ancient Hindu temple beneath a 16th century mosque at the controversial site in Ayodhya (Science, 28 March, p. 1958).

    The state court had ordered the excavation after ground-penetrating radar suggested the presence of structures under the rubble of the mosque, which was torn down by a Hindu mob in 1992. An Indian newsweekly, Outlook, has reported that the dig so far had yielded terra-cotta sculptures of humans and animals, structures that look like pillar bases, skeletons, and a stone slab with an inscription that could be Ram's name in ancient Devanagri. Mani has been replaced by Hari Manjhi, ASI's director of antiquities and museums, although he remains a member of the team.

  5. Sidelines

    Shrugging off Atlas. Attendees at the American Society for Microbiology's annual meeting in Washington, D.C., last month were caught off guard when Ronald Atlas staged a bioterrorism threat during his presidential address. Atlas and Rick Clover, who co-direct the Center for Deterrence of Biowarfare and Bioterrorism at the University of Louisville in Kentucky, had planted a mock smallpox patient in the auditorium lobby before Atlas's speech to see if researchers could recognize the disease and respond appropriately.

    When nobody reacted, Atlas interrupted his talk and summoned the patient-actor, covered with visible pustules, to walk up on stage. “For example, nobody picked up the phone to call 911,” says Atlas, who had placed observers in the crowd to monitor people's response to the patient's presence.

    Harvard microbiologist Gregory Priebe says he thought the act “was a bit overblown, although it did make a point about the need for public awareness.”

  6. Separate Ways

    Built to keep out marauding tribes, the Great Wall of China, completed during the Ming dynasty (A.D. 1368–1644), has affected the course of plant as well as human history.

    Great divider.

    CREDIT: (TOP) HONGYA GU

    “The Great Wall has served as a physical barrier to gene flow between [floral] subpopulations separated for more than 600 years,” according to plant geneticist Hongya Gu of Beijing University. Gu and colleagues studied one population from each of the four species of insect-pollinated plants and two species of wind-pollinated plants that grow on both sides of the Great Wall. They report in the March issue of Heredity that, compared with control plants from two sides of a road, there was “significant genetic differentiation” between plants and their counterparts on the other side of the 2400-kilometer wall, whose height ranges up to 7.1 meters. Wind-pollinated species showed less differentiation than insect-pollinated species. “This is a fine example [of] how easy it is for populations to diverge,” especially because of the absolute dating, says Peter Raven, director of the Missouri Botanical Garden.

  7. Transgenic Tombstone

    It's all very well to plant Rover under a rosebush. But a pair of students at the Royal College of Art in London have a better idea: one that would keep your dog's—or your own—DNA perpetuated indefinitely. The project is called Transplant Biopresence, and it entails inserting human DNA into trees.

    Georg Tremmel and Shiho Fukuhara say they are looking for funding and scientific collaborators. If all goes as planned, they hope to have a transgenic testimonial tree created in a year. To begin, they plan on transferring snippets of their own DNA so that every cell of the tree will carry them. A standard approach is to insert DNA into the chromosome of a plant cell, then use hormones to regenerate an entire plant. They plan to work full-time on the project after graduating in July. Eventually the duo hopes to insert an entire human genome that would replace a tree's junk DNA.

    “It may be art, but I don't think it will work,” says plant geneticist Rick Meilan of Oregon State University in Corvallis. Chucking out so-called junk DNA may remove cryptic yet essential functions for the plant, he says, and adding human DNA would likely toss new wrenches into the genetic machinery.

  8. Awards

    Chemistry prize. Organic chemist Ronald Breslow, 72, has won the 2003 Welch Award for lifetime contributions to basic research. Breslow, a professor at Columbia University and a past president of the American Chemical Society, receives the $300,000 prize for his work in biomimetics, including the synthesis of novel compounds for chemotherapy. The award is funded by the Houston-based Welch Foundation, which supports chemical research at Texas institutions.

  9. Data Points

    Overrotation. The National Science Foundation's (NSF's) grantsmaking staff is top-heavy with temporary employees, according to a new internal report. The latest tally shows that only 139 of 334 program officers—the professionals who manage the process of deciding which proposals get funded—are permanent employees. The rest, some 59%, typically spend 1 to 3 years at NSF on leave from jobs at universities or elsewhere.

    Such “rotators” constitute a valuable stream of fresh talent, says NSF Director Rita Colwell. They also allow NSF to handle a rising workload despite a cap on permanent staff slots. But federal lawmakers have begun to worry that temporary employees could weaken NSF's institutional memory and jeopardize its oversight of long-term projects. A 60/40 split would be “ideal,” Nat Pitts, head of NSF's Office of Integrative Activities, told the National Science Board during a presentation last month. He added that “we may [currently] be a tad out of balance.”

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