Random Samples

Science  23 Dec 2005:
Vol. 310, Issue 5756, pp. 1900
  1. Mayan Masterpiece

    CREDIT: KENNETH GARRETT/NATIONAL GEOGRAPHIC

    This detail is from what archaeologists say is the earliest known Maya painting, a large mural dated from 100 B.C.E. The January issue of National Geographic will describe its discovery at the site of San Bartolo in Guatemala.

  2. The First Americans

    An analysis of ancient Brazilian skulls has lent new weight to the controversial theory that not one but two distinct populations from Asia colonized the Americas.

    Scientists have long believed that starting about 12,000 years ago, the ancestors of present-day American Indians migrated from northeast Asia across the Bering land bridge. But in recent years, Walter Neves of the University of Säo Paolo in Brazil has argued that these immigrants were preceded by people from Southeast Asia who came from the same stock that settled Australia and Melanesia.

    Last week, Neves and his colleague Mark Hubbe claimed new support for this idea from an analysis of 81 skulls, ranging in age from 7500 to 11,500 years, found in the Lagoa Santa region of southeast Brazil. Detailed comparisons revealed that the skulls did not resemble people from northeast Asia, who tend to have short, wide skulls with relatively flat faces, but rather took after present-day people from Australia and Melanesia, whose skulls tend to be long and narrow with projecting faces. Because other, similar ancient skulls have been found in North and South America, Neves and Hubbe concluded in a paper published online in the Proceedings of the National Academy of Sciences that two distinct populations probably colonized the New World.

    Physical anthropologist Clark Larsen of Ohio State University in Columbus cautions that changes in diet over time can modify the jaw muscles in ways that also alter skull shape, without major genetic changes. Nonetheless, says archaeologist Tom Dillehay of Vanderbilt University in Nashville, Tennessee, “Neves is building a more solid case.”

  3. What's in a Tooth?

    CREDIT: GLENN WILLIAMS; INSET: MARTIN NWEEIA

    The male narwhal has long fascinated whale researchers, who have puzzled over the function of the 2.5-meter-long spiral tusk that juts out from its upper jaw, like the horn of the mythical unicorn. Now dentist Martin Nweeia, who teaches at Harvard School of Dental Medicine in Boston, has revealed that the tooth is not an icebreaker or a weapon as some have thought, but a sensor.

    At the 16th Biennial Conference on the Biology of Marine Mammals in San Diego, California, last week, Nweeia reported from lab studies and narwhal observations in the Canadian Arctic that the tooth has an extremely sensitive surface with millions of tiny nerve endings. It can detect changes in water temperature and pressure, and chemicals that enable the whales to gauge salinity—an indication of ice formation—and find fish to eat.

    Nweeia now plans to put water-filled plastic gaskets around 45-cm lengths of teeth on Arctic narwhals and monitor—via brain and muscle electrodes as well as hydrophones—the whales' responses to different salinity levels.

  4. Signs Support Chomsky

    A study of several deaf people who improvised a form of sign language to communicate with their families lends weight to what linguist Noam Chomsky first argued in the 1950s: that grammar is innate rather than learned.

    The study, by cognitive scientists Marie Coppola and Elissa Newport of the University of Rochester in New York, focused on three young deaf adults, each raised in an isolated area of Nicaragua with no contact with anyone who knew formal sign language.

    To see if the three so-called home signers employed the grammatical concept of “subject,” Coppola showed them 66 videotaped events in which subjects were either active (such as “John”) or inanimate (such as a door). The signers were then asked to describe to a family member what had happened. The signers nearly always began their description with the subject—an indication to Coppola and Newport that they had incorporated this grammatical concept.

    To make sure, the researchers did a second study in which they showed vignettes depicting events in which characters changed from being active agents to being the “topic” of an action (for example, a woman arranges some flowers, then a man kisses her.) Again, the signers always put the subject at the beginning, the researchers reported online last week in the Proceedings of the National Academy of Sciences.

    “Home signers could get their message across” without using grammatical concepts, says psychologist Ann Senghas of Barnard College in New York City. But this study shows that even when people make up their own sign language, “language-learning and language-processing mechanisms kick in.”

  5. Ice Ages as History

    “Anthropogenic climate change will basically produce another planet.… Earth won't have another ice age until humans go extinct.”

    —James Hansen of NASA Goddard Institute for Space Studies in New York City on 6 December at the meeting of the American Geophysical Union in San Francisco.

  6. Pioneers

    CREDIT: JON CHASE/HARVARD UNIVERSITY NEWS OFFFICE

    Amazing racer. What a year it has been for William Tan. The 48-year-old neuroscientist took time off from his research to compete in wheelchair races around the globe, including a grueling marathon spanning all seven continents. In the process, he raised $1.5 million to establish a professorship in pediatric oncology at his alma mater, the National University of Singapore (NUS).

    Stricken with polio at age 2 and paralyzed from the waist down, Tan has been a marathoner since 1980 and has raised more than $14 million for charitable causes around the world, including children with disabilities, needy patients requiring dialysis treatments or prosthetics, and victims of the 11 September 2001 terrorist attacks. The seven-continent challenge—which Tan completed in 10 weeks—included a harrowing ride across Antarctica's alternately steep, rocky, and slushy terrain. “At one point, I sank 2 feet into the … slush and had to be pulled out by five runners,” he says. Still, he finished the 42-kilometer race. Tan's tenacity and energy are “incredibly inspiring,” says NUS president Shih Choon Fong.

    With his marathon year drawing to an end, Tan will return to St George Hospital in Sydney, Australia, as a resident in internal medicine. He also plans to continue neuroscience research.

  7. Sidelines

    CREDIT: BECKMAN INSTITUTE FOR ADVANCED SCIENCE & TECHNOLOGY

    Brain of the month. 2003 physics Nobel Prize-winner Anthony Leggett—and his brain—appear as Mr. January in a new calendar produced by the Beckman Institute for Advanced Science and Technology at the University of Illinois, Urbana-Champaign.” Big Brains on Campus” features a dozen staff members to showcase the institute's magnetic resonance imaging resources. The image of Leggett's brain highlights his cerebral cortex, a potential wellspring of his ingenuity. A scan of women's basketball coach Theresa Grentz, Ms. March, zooms in on her limbic system, a possible source of her passion for the game. See www.beckman.uiuc.edu/bigbrains.html

  8. Three Q's

    CREDIT: SAM OGDEN

    David Page has spent his entire career at the Whitehead Institute for Biomedical Research in Cambridge, Massachusetts, which shares faculty with the Massachusetts Institute of Technology (MIT) but is run by its own board. This month, the 49-year-old geneticist was named its fourth director.

    Q: An “artist colony extraordinaire” is how you describe Whitehead. Are you serious?

    A: Absolutely. We live by the credo of academic freedom. We hire people, invest in their careers, and let the faculty chart their own paths. We identify the most creative people and let 'em loose.

    Q: There are rumors that MIT might try to absorb Whitehead. Would you back such a move?

    A: That's news to me! I do not report to the president of MIT; we have our own board of directors. In terms of day-to-day academic life, we are joined at the hip with MIT. That relationship is a tremendous benefit, since we can turn on a dime. No, I wouldn't change that.

    Q: Whitehead is now quite literally in the shadow of Novartis, the MIT McGovern Institute, and the new Broad Institute founded by former Whitehead researcher Eric Lander. Does that leave you feeling anxious?

    A: I'm amused by a lot of the conversation about biomedical research models, since the premise is that there surely is one right model. I'd suggest that we want to see a diverse portfolio and different business plans. And our business plan is to maintain the best artist colony we can.

  9. In Brief

    ⚫ John O'Keefe of University College London and Lynn Nadel of the University of Arizona in Tucson are the joint winners of the $200,000 Grawemeyer psychology award, given by the University of Louisville in Kentucky. They receive the honor for their work on the brain's mapping system.

    ⚫ Darrell Kirch has been chosen to be the next president of the Association of American Medical Colleges (AAMC). Currently senior vice president for health affairs at Pennsylvania State University, University Park, Kirch will assume the post when current AAMC president Jordan Cohen steps down in June 2006.

  10. Money Matters

    CREDIT: JUSTIN IDE/HARVARD UNIVERSITY NEWS OFFICE

    Out of state. Political opposition to human embryonic stem (ES) cell research in Missouri has produced a windfall for Harvard University developmental biologist Kevin Eggan. It comes as a 5-year, $6 million grant from Jim and Virginia Stowers, founders of the Stowers Institute for Medical Research (SIMR) in Kansas City, that will be channeled through the newly incorporated Stowers Medical Institute in Cambridge, Massachusetts.

    Eggan is the first university researcher to receive funding from the Stowers, whose previous gift of $2 billion has been used only at SIMR. Some Missouri legislators want to outlaw research on ES cells and somatic cell nuclear transfer, and SIMR officials hope that Eggan's grant will help persuade Missouri residents to support a constitutional amendment to protect such research. Eggan says the money will go toward his work on human ES cells, including efforts to create new cell lines using nuclear transfer.