Random Samples

Science  24 Oct 2003:
Vol. 302, Issue 5645, pp. 561

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  1. Limits to Fitness

    Can running make you stupider? A team of scientists in California and Wisconsin have shown that if you're an exercise nut—and if you're anything like a mouse—adding more neurons to your brain won't do it any good.


    Exercise helps new neurons form in the mammalian hippocampus, a brain area vital in learning and memory. But is a bigger hippocampus necessarily better?

    Scientists led by behavioral neuroscientist Justin Rhodes of the Oregon Health and Science University in Portland tested that idea with specially bred hyperactive mice. Those that ran regularly on exercise wheels did add neurons. But, unlike the case with normal mice, the cells did nothing to improve spatial skills in a test that required them to remember the location of a submerged platform while swimming in darkened water. In fact, the runners actually performed worse than their nonrunning hyperactive colleagues, the team reports in the current issue of Behavioral Neuroscience.

    Rhodes, who conducted the work as a graduate student at the University of Wisconsin, Madison, says the born-to-run mice are “addicted to exercise” and that in their case running “actually is impairing learning.” Co-author Fred Gage of the Salk Institute in La Jolla, California, says the experiment may explain “why the increased activity in hyperactive kids does not lead to cognitive enhancement.”

  2. Bio-Utopia

    Last year, it was cloning. This year, the President's Council on Bioethics is reporting on a much bigger subject: the future of humans. Entitled Beyond Therapy: Biotechnology and the Pursuit of Happiness, the report (at http://www.bioethics.gov/), released last week at the commission's meeting in Washington, D.C., eschews recommendations but is cautious about jumping into a brave new world of better babies, improved performance, ageless bodies, and unalloyed happiness.

    The commission looks askance at futuristic boosterism such as that from the National Science Foundation, which has proclaimed that “improvement of human performance … could achieve a golden age.” Says the report: “We might relish the superior results … but we would have gone very far, potentially, in losing sight of why excellence is worth seeking at all, and hence what excellence is.”

    With regard to the quest for physical perfection, the commission asks: “Will people in 2050 think that they are entitled to have any and all of their weakened parts replaced, and not just once?” In the same vein, it worries that with reproductive technologies people will see children not as “unconditionally welcome gift[s]” but as “conditionally accepted product[s].”

    One commission member, Harvard University political scientist Michael Sandel, summed up “the real question” posed by the report: “What was wrong with eugenics in the first place?” If it was just the coercion part, he asked, “is it OK now to have free market, consumer-driven eugenics?”

  3. Chaco Corn Import

    Archaeologists have long wondered how the people of New Mexico's Chaco Canyon managed to grow enough food in that arid environment to support what was apparently a flourishing population from the 9th to 12th centuries A.D.


    The chemical signatures on 1000-year-old corncobs may hold the answer, according to a team led by geochemist Larry Benson of the U.S. Geological Survey and archaeologist Linda Cordell of the University of Colorado in Boulder. Finding that maize takes on the isotope ratios of trace elements in the soil where it grew, the team compared isotope signatures of two sets of corncobs—from a Chaco “great house” and from a newer house 100 kilometers away—with possible agricultural areas outside the canyon. They found that the older corn probably originated 80 kilometers away at the base of the Chuska Mountains. The later corn most likely came from the floodplains 90 kilometers to the north, they reported online last week in the Proceedings of the National Academy of Sciences.

    Mollie Toll, a paleoethnobotanist at the Museum of New Mexico in Santa Fe, suggested a similar pattern of corn trade 20 years ago, based on the appearance of the cobs. But “there'd been no way to test the ideas before,” she says.

  4. Fussy Eating in the Genes

    Very young children mostly eat whatever they're offered, but at around age 2 they get picky. Now, a study by health behaviorist Lucy Cooke of University College London, U.K., argues that neophobia—the fear of new foods—may have evolved to protect us from poisoning ourselves as we become toddlers.

    To test the idea, Cooke and her team collated data on neophobia and diet from 564 questionnaires filled in by the parents of children of the fussiest ages, between 2 and 6. In the October issue of Appetite, the team reports a significant correlation between high pickiness and low consumption of green vegetables, meat, and fruit. There was no such correlation with other foods, including chips, cookies, and potatoes. That makes sense, the authors say, because in the past, “plant toxins [could have been] very dangerous to children, as could the effects of food poisoning from meat,” says Cooke. Co-author Lee Gibson says that children are especially wary of bitter-tasting vegetables such as green peppers, brussels sprouts, cabbage, and spinach. Toxic plant alkaloids taste bitter, he notes, and they could be more dangerous for children than adults.

  5. Nonprofit World

    Policy failure. Columbia University has shuttered its science policy think tank in Washington, D.C. The 4-year-old Center for Science, Policy, and Outcomes was run by Daniel Sarewitz (below), a geologist and former congressional aide.


    The center's demise is a result of “changes in priorities and in administration,” says Sarewitz. That's shorthand for the transition from George Rupp to Lee Bollinger as president and the departure of vice provost Michael Crow to lead Arizona State University. Sarewitz is hoping to interest other funders in the idea of “an operational center in D.C. that's focused on making better use of scientific results in shaping national policies.” But he admits that a science policy shop is a tough sell in the nation's capital.

  6. Milestones

    Coast to coast. Lured by Florida Governor Jeb Bush, the Scripps Research Institute in La Jolla, California, hopes to convince legislators to finance a new campus in Florida that will turn biomedical discoveries into drugs. On 9 October, Bush and Scripps President Richard Lerner announced plans to create a 500-staff research center in Palm Beach County that will require start-up funding from state and local governments.

    Bush has promised Floridians that the Scripps campus will bring jobs and economic development through spinoff companies. Scripps, for its part, has been mulling a move into drug development “for a while,” says Lerner: “It's a natural outlet to our chemistry.” The state is expected to finance the start-up costs: Palm Beach County has approved $140 million, and Bush planned to ask the Florida legislature this week to devote $310 million in federal economic stimulus funds that will help build a new 33,800-square-meter facility.

    The new branch, to start operating in rented space in early 2004, will design and test drugs and do some technology development. None of Scripps's San Diego staff will be asked to move, says Lerner.

  7. Awards

    Pioneers. Carver Mead (top), a Caltech engineer and entrepreneur whose design of very large-scale integrated circuits became a cornerstone for modern computing, received the National Academy of Engineering's Founders Award at its annual meeting in Washington, D.C., last week. In addition, the academy honored physicist Robert Frosch (bottom) with the Arthur M. Bueche Award for pioneering the field of industrial ecology.


    Mead's list of accomplishments includes the invention of the MESFET transistor, a component in several telecommunications devices. Frosch, a former NASA administrator, is widely recognized for integrating environmental concerns with technology development.

    The academy also inducted 77 new members—including four women—and nine foreign associates elected earlier this year (http://www.nae.edu/).

    Minority views? The National Institutes of Health (NIH) got a pat on the back for promoting workforce diversity last week from a Washington, D.C.-based nonprofit association. But that rosy assessment doesn't square with the experiences of many black scientists on the Bethesda, Maryland, campus.

    The award, from Diversity Best Practices, cites the 35% minority component of NIH's 18,000-person workforce. But minority employee organizations say that statistic masks a much lower representation of minorities at professional levels. Of 1238 tenured and tenure-track scientists in NIH's intramural program, for instance, only 18 (1.5%) are African American and 37 (3%) are Hispanic. (The two groups comprise 23% of the U.S. population.) Asians are overrepresented at 11.3%, whereas the three Native American scientists on campus are statistically invisible.

    Health physicist George Redman, a founding member of the NIH Black Scientists Association, blames “the culture at NIH,” which he says remains “a major impediment to attracting minority scientists” despite the presence of several programs to encourage minority participation. “A number of minority scientists here have had bad experiences,” he says, “and bad news travels fast.”

    But NIH officials say that the agency is working aggressively to change that perception, and that several minority scientists have been named to leadership positions since Elias Zerhouni took office 18 months ago. “Of course, there's more to be done,” says Larry Self, director of the Office of Equal Opportunity and Diversity. “But we've made some serious gains over the past year.” Zerhouni was one of 10 CEOs from around the country to receive the award, and the only government official.

  8. Explorers

    Fisheye view. When biological oceanographer Marsh Youngbluth boarded a four-person research submersible off the Gulf of Maine last month to study a large jellyfish species, his pilot, Tim Askew, asked if they couldn't do something more exciting. Askew got his wish: 900 meters under water, a 4.5-meter Greenland shark appeared out of nowhere and swam straight toward the sub's front sphere.


    The shark crashed softly against the glass, freezing the crew, before turning and swimming away slowly. Youngbluth, a researcher at Harbor Branch Oceanographic Institution in Ft. Pierce, Florida, shot the scene with a hand-held video camera (www.at-sea.org/missions/maineevent4/day14.html).

    Greenland sharks are known to have extremely poor eyesight, which could explain the collision. But fortunately for scientists, natural encounters with the seal-eating fish are rare.