News this Week

Science  29 Jun 2001:
Vol. 292, Issue 5526, pp. 2408
  1. WHITE HOUSE

    President's New Adviser Ready to Put Science in Its Place

    1. Andrew Lawler

    After a long vacancy, the nation's top science job may be filled by fall. President George W. Bush last week chose John H. Marburger III, a 60-year-old physicist, former university president, and current national lab chief, as his nominee for the post. Marburger vows to bring scientific rigor to the Administration's decisions but warns that he will be just one of many voices offering advice on hot-button issues such as ballistic missile defense, stem cells, and global warming.

    Marburger's nomination, first reported by Science's online daily news service, ScienceNOW (sciencenow.sciencemag.org), was sealed in a 15-minute Oval Office meeting with Bush on 20 June. A lifelong Democrat, Marburger says he will keep personal opinions to himself—and he advises the rest of the community to do the same. “Let's not put science in the position of opposing but in the position of informing,” adds Marburger, who directs Brookhaven National Laboratory on Long Island and served as president of the State University of New York, Stony Brook, for 14 years.

    Science policy officials greeted Bush's choice with plaudits—and relief. Many were pleased to learn that the White House will now get a boost in technical competence, after worrying that the president has made some key R&D-related decisions without adequate scientific advice (Science, 11 May, p. 1041). Marburger is “smart, sensible, cautious—but candid,” says Neal Lane, science adviser to former President Bill Clinton and now a physicist at Rice University in Houston. “I feel really good about the appointment.” Adds Massachusetts Institute of Technology physicist Ernest Moniz, former chief scientist at the Department of Energy (DOE), which oversees Brookhaven: “This is a good choice: He has both academic and lab expertise.”

    Marburger took the Stony Brook job in 1980 after leaving the University of Southern California in Los Angeles, where he was dean of arts and sciences and a researcher in nonlinear optics. As Stony Brook's president, he built up a modest health science research and clinical program as well as a high-energy physics effort. He also headed the 80- member Universities Research Association during the political battles over the Superconducting Super Collider, which was cancelled.

    Colleagues describe Marburger as a gregarious manager with broad interests and a sophisticated understanding of the relation between science and politics. Those skills were put to the test in 1998, when DOE brought him in to rescue Brookhaven from a crisis in which researchers and community activists were battling over claims that the lab was endangering the environment (Science, 25 February 2000, p. 1382). Some scientists, grumbling that Marburger may be too well attuned to public relations, are still angry that DOE shut a research reactor at Brookhaven on Marburger's watch. “People are disappointed he doesn't show more passion for research,” complains one Brookhaven researcher who thinks that nuclear physics got shortchanged.

    Marburger insists that the lab was losing public support and that fighting to save the reactor would have been a mistake. Indeed, many applaud his efforts to create an atmosphere of trust between activists and scientists. “He took a nervous, fearful, and hostile community and did a remarkable job turning it around,” says Patricia Dehmer, chief of DOE's basic energy research division. Community activists agree. DOE has consistently given high marks to Brookhaven's operator—Brookhaven Science Associates, a consortium of Stony Brook and Battelle Memorial Institute—since it took over in 1998 with Marburger as director.

    Filling a vacuum.

    Marburger, here beside a Brookhaven accelerator, will lead the White House science office.

    CREDIT: COURTESY OF BROOKHAVEN NATIONAL LABORATORY

    In his new job, Marburger says he will stick to providing scientific and technical, not ethical, advice. On stem cell research, for example, he says “no one doubts stem cells are valuable to research and hold tremendous promise—on that, there's no scientific controversy.” But he adds that the matter “is not going to be decided by science.”

    Marburger acknowledges that climate studies have shown that human activity is at least partly responsible for global warming. But he says the decision on what to do about that knowledge involves other factors, such as the economic impact of the Kyoto Protocol, which he says could be “kind of scary” for the United States. Marburger defends the Administration's recent decision to call for additional global change research following the release of a National Research Council report (Science, 15 June, p. 1978). “There is some uncertainty,” he says, adding, “we do need more information to draft an effective policy.”

    Strategic defense issues will present another challenge for Marburger. He characterizes the current policy of mutually assured destruction as “bordering on insanity” and notes that “now we have a president with the courage to change that.” As for ballistic missile defenses, he says that “no one wants to propose a system that doesn't work. The question is what can be done.”

    Old science policy hands say Marburger's lack of Washington experience could make it difficult for him to penetrate the White House's tight-knit fraternity. “The question is whether he will be marginalized as an outsider, as a representative of the scientific community,” says one former White House official. “That is the death knell for any adviser.” But Lane says Marburger's ability to get along with people will serve him well. “It's all about people there,” says Lane. “No amount of rational argument and well- reasoned memos replace creating trust.”

    Marburger's Senate confirmation as director of the Office of Science and Technology Policy may not come until fall, but one Administration official predicts it will prove “a cake walk.” That may be too late, however, for him to put his stamp on the 2003 budget proposal, which is already in the works.

    Marburger says he was impressed during his Oval Office meeting by the president's willingness to listen and his “acute grasp of the fundamentals.” The nominee adds that he did not insist on any “formal access” to Bush, but that he is satisfied he'll be able to work closely with the president and his team. The challenge for Marburger will be to maintain the detachment he advocates while making an impact on the White House's rough-and-tumble politics.

  2. SCIENCE POLICY

    Bush Grapples With Stem Cells, Cloning

    1. Gretchen Vogel

    As summer temperatures hit Washington, D.C., last week, debate over human cloning and research on human embryonic stem (ES) cells—two separate but intertwined issues—heated up as well. Congress held two hearings on whether to ban human cloning, a decision that could affect work with ES cells; the National Academy of Sciences (NAS) hosted a meeting on the scientific promise and puzzles of stem cell research; and the National Institutes of Health (NIH) delivered a 200-page tome—all fodder for President George W. Bush's imminent decision on whether to allow federal funding of research with these cells, which are derived from week-old embryos. Meanwhile, rumors swirled about a major split within the Administration.

    Of the two issues, human cloning is less contentious. The vast majority of scientists and lawmakers oppose any attempts to produce a child by cloning. They are split, however, on how narrowly defined any ban should be. Some researchers would like to use somatic cell nuclear transfer—the method used to create Dolly—to explore ways to make genetically matched stem cell lines for patients. The idea is to use a patient's cell to create a cloned embryo, from which scientists could derive EScells. A bill introduced by James Greenwood (R-PA) in early June would allow scientists to conduct such research with human cells but would prohibit the creation of embryonic clones with the intent to implant them in a uterus. A second bill, introduced by Dave Weldon (R-FL) and Bart Stupak (D-MI), would ban all use of somatic cell nuclear transfer in human cells, with the ban to be revisited in 5 years.

    At a 20 June hearing weighing the benefits of the two bills, Tom Okarma, president and CEO of Geron Corp. in Menlo Park, California, argued against a ban on research cloning. He doesn't foresee producing genetically matched ES cells for therapy anytime soon—the approach is impractical and far too expensive, he says—but he argued that research on nuclear transfer in humans is vital to the future of so-called regenerative medicine. Geron's goal, he explained, is to understand how an egg can reprogram the nucleus of an adult cell so that it can once again direct the entire process of development. Ideally, such research might enable scientists to transform a skin cell directly into a pluripotent stem cell without using an oocyte or creating an embryo.

    Alexander Capron, a bioethicist at the University of Southern California in Los Angeles, is not convinced. In a separate hearing, he supported the Weldon bill's complete moratorium, saying that the prospects for a scientific payoff from research cloning do not yet justify the risk. Capron worries that if embryos are created, for whatever reason, some renegade will inevitably implant one in a womb. But if future research in animals convincingly demonstrates the therapeutic potential of ES cells derived from clones, then the benefit would outweigh the risk, Capron said.

    The Administration, which has been playing its cards close to the chest, tipped its hand at one of the cloning hearings. Claude Allen, deputy secretary of Health and Human Services (HHS), told the hearing that the Administration opposes any form of somatic cell nuclear transfer with human cells—even for research purposes. Although some advocates of ES research saw this as an indication that the Administration is also likely to decide against federal support for any research using ES cells, Allen said the two issues are separate and reiterated that President Bush had not yet made his decision on ES cell research.

    In Congress, support seems to be building for ES cell research—from some unexpected corners. Orrin Hatch (R-UT), a vocal abortion opponent, wrote to President Bush on 13 June urging him to allow federal funding. And Trent Lott, Senate minority leader and another abortion opponent, said on NBC's Meet the Press that the research had great potential. He declined to say whether he supported federal funding, however.

    HHS Secretary Tommy Thompson has been circumspect in his public comments. But the former Wisconsin governor has long been a supporter of ES cell research, and scientists who have spoken with him say he was encouraging. His views evidently contrast with those of Karl Rove, the president's chief political strategist, who reportedly worries that supporting stem cell research will alienate Bush's antiabortion supporters.

    To prepare for the Administration's decision, Thompson requested both a scientific and legal review of guidelines proposed last year by NIH that would permit federal funding of research on ES cells. On 20 June, NIH's office of public policy forwarded him a 200-page document that reviews published results with embryonic, fetal, and adult stem cells. (It is not slated for public release.) The legal review is ongoing, says HHS spokesperson Bill Hall.

    Opponents of research with ES cells often tout the benefits of stem cells derived from adult tissue, claiming they are just as versatile—and obviously far less controversial. But a symposium at the NAS on 22 June underscored the scientific consensus that it is still too early to tell which source of stem cells will prove most useful.

    Indeed, one of the more promising recent studies using adult stem cells turned out to be less so, according to the researcher, developmental biologist Margaret Goodell of Baylor College of Medicine in Houston. In December 1999 she reported that muscle tissue contained stem cells that could become blood—raising the hope that adult tissues might harbor versatile stem cells that could, if prompted, become a variety of tissues. But in subsequent research she has found that muscle contains two distinct stem cell types, one destined to become blood and another destined to become muscle. The work has just been submitted for publication, Goodell says, but it suggests that scientists and policy-makers “can't yet leap to assumptions that we can use [adult-derived] cells for everything.”

  3. SCIENCE PUBLISHING

    Lab Chief, Postdoc Clash Over Nanotech Paper

    1. Eliot Marshall

    Peter Schwartz says he knew he was getting into trouble when he clashed with his lab director last year over a nanotechnology problem that Schwartz claims to have solved. But he didn't realize how much trouble. Now, Schwartz says, he has been blocked from publishing his results, and he claims it's a classic example of a senior scientist clamping a lid on a junior colleague. But his former boss, Chad Mirkin, a chemistry professor at Northwestern University (NU) in Evanston, Illinois, and leader of a world-class nanotechnology group, strongly disagrees. Schwartz did some research “under my guidance,” says Mirkin, then “he left the lab and tried to pass the work off as his own.”

    Mirkin and Schwartz do agree on this: A prestigious chemistry journal—Langmuir—was ready to publish Schwartz's report on a method of nano-scale DNA printing until Mirkin intervened in March. The publisher, the American Chemical Society (ACS), rejected an appeal from Schwartz on 14 June, effectively spiking the paper. This spat, which has generated several news stories, illustrates how academic differences in science increasingly involve commercial and legal battles as well.

    Would-be author.

    Authorship dispute blocks Schwartz's paper at Langmuir.

    CREDIT: COURTESY OF PETER SCHWARTZ

    The disagreement began more than a year ago in Mirkin's NU lab, according to Schwartz's records. The 37-year-old physicist says Mirkin hired him to work on a process developed by Mirkin and postdoc Seunghun Hong called “dip-pen” nanolithography (DPN) for printing molecular “ink” (Science, 29 January 1999, p. 661). Schwartz says his task was to improve the lab's method of printing DNA, which might be valuable for mass-producing DNA chips or, eventually, molecular electronic applications. Schwartz says, however, that he was unable to reproduce the lab's earlier DNA printing results. He began experimenting with a different technique called “nanografting,” developed by Gang-yu Liu of Wayne State University in Detroit. Eventually, Schwartz says, he developed “meniscus-force nanografting” and used it to print lines of DNA as small as 15 nanometers wide.

    Schwartz claims that relations with the lab soured after Mirkin ignored his informal critiques of DPN, prompting Schwartz to talk about the matter more publicly at a lab meeting. After that session, Schwartz received a letter from Mirkin, dated 1 July 2000, reprimanding him for “insubordinate behavior” and “belligerence” toward his colleagues. Mirkin also reminded Schwartz in the letter that his contract was about to expire and that he should turn over his notebooks to Hong, whose results Schwartz had challenged. Instead, Schwartz continued his research with the help of another lab member. Starting in July, Schwartz also had several talks with Lydia Villa-Komaroff, NU's vice president for research, explaining that he wanted to complete his own experiment, file a provisional patent, and publish the results. At the time he was looking for an academic job and is now an instructor at California Polytechnic State University in San Luis Obispo.

    Schwartz left NU in August 2000, and, he says, after Mirkin stopped communicating with him, he submitted a manuscript on his own—first to Nature, which rejected it, then to Langmuir. Four independent reviewers vetted the manuscript for Langmuir, and an associate editor accepted it. Liu, who has read the paper, says it is “a very nice piece of work” that others in the field should see. She adds: “We need as many flowers as possible in the garden” of nanolithography.

    In October 2000, Schwartz filed a provisional patent application, he says, listing NU and Mirkin as co-inventors. He claims he did this to protect the university's interests before he began giving public talks in labs where he was seeking employment. Schwartz says he notified Villa-Komaroff and separately wrote to Mirkin offering to include him as a co-author on the paper. Schwartz says he received no response from Mirkin; Villa-Komaroff responded that he should not try to publish without Mirkin's input. She says Schwartz's decision to seek patents was “premature” and may have compromised Mirkin's intellectual property. The university “has a responsibility to help mediate” disputes such as this, she says, but not to resolve them.

    After Langmuir accepted the paper in early March, Mirkin wrote to the journal's editor, David Whitten, arguing strongly against publication. Members of the Mirkin lab also sent letters backing Mirkin. Among other things, Mirkin wrote, publishing the paper would be unethical if it didn't include other lab members as co-authors. But, he added, simply including their names wouldn't solve what he considered the main problem with the paper: Mirkin and other lab members say they need more information to reproduce the results. Finally, Mirkin raised a legal issue: Langmuir “has tarnished my reputation by willfully sending this manuscript out to review … with only Schwartz's perspective,” Mirkin wrote. Premature publication would also affect the group's intellectual property, said Mirkin, who urged Langmuir not to go ahead, “knowing that there is a significant and documented authorship issue as well as a major scientific problem.”

    Langmuir cancelled plans to publish the paper. After getting legal advice, ACS's director of publishing operations, Mary Scanlan, wrote to Whitten that the society “cannot publish the manuscript … until the matter of authorship is resolved,” and that “it is not the function of the ACS to act to resolve authorship disputes.” Whitten could not be reached for comment.

    Schwartz says he doesn't want to withdraw the paper: “I just want it to be published.” Mirkin says he's defending the authorship rights of his team: “It's really unusual to have a situation like this. I have never experienced it before, and I don't know anyone else who has.” If his team at NU can reproduce Schwartz's work, Mirkin says, he will try to publish a paper that includes Schwartz as a co-author.

  4. ULTRAFAST LASERS

    Lighting the Way to a Quantum Computer

    1. Robert F. Service

    For researchers working to build a quantum computer, speed is of the essence. The bits of quantum data that scientists create last just billionths of a second, or nanoseconds. That's too short to allow researchers to do any meaningful computation. But a group of California and Pennsylvania researchers may have found a way to beat the time crunch. Their work takes a small but important step toward creating a machine that can carry out in seconds calculations that would take eons on even the most sophisticated supercomputer.

    On page 2458, physicist David Awschalom and his colleagues at the University of California, Santa Barbara (UCSB), and Pennsylvania State University, University Park, report a new ultrafast way to manipulate bits of quantum data. Using a trio of vanishingly brief laser pulses, the team managed to tweak bits of quantum data in as little as 100 quadrillionths of a second, or femtoseconds. At that rate, they could theoretically carry out 1 million such manipulations before the quantum information falls apart. The group hasn't demonstrated any computation power yet. Nevertheless, the ability to manipulate quantum information so quickly “is a very important milestone,” says Stuart Wolf, a quantum-computer expert at the Pentagon's Defense Advanced Research Projects Agency in Arlington, Virginia.

    In both conventional and quantum computers, data are represented by bits that reside in one of two states, a 0 or 1. But quantum computers have an extra trick. They take advantage of the fuzzy notion of a superposition of states from quantum mechanics, which says that a quantum system—such as the orientation of an electron's spin—exists as a superposition of all its possible states at once until it is measured or observed. Instead of being a simple 0 or 1, a quantum bit, or qubit, can be 63% 0 and 37% 1, or 51% 0 and 49% 1. When this fuzzy qubit is plugged into a logical operation, the computer essentially computes all possible outcomes simultaneously. String just 300 qubits together, and a quantum computer would instantly calculate all 2300 possible results, a number roughly equivalent to all the elementary particles in the universe.

    Spin control.

    Laser pulses make electrons spin in unison around the axis of a magnetic field, tip the spins, and measure the result.

    ILLUSTRATION: A. STONEBRAKER

    Although still far from that goal, quantum-computation experts have made some headway. The most promising approach creates qubits by using magnets to manipulate the spins of atomic nuclei in molecules in solution. Such liquid qubits maintain their information up to seconds at a time before they “decohere,” or fall apart. That gives researchers ample time to coax them into carrying out rudimentary logical operations. The downside is that it's difficult to scale the technique up by coupling many qubits together.

    Two years ago, a team of Japanese researchers made a qubit in a tiny solid state device, which carried the potential to be scaled up readily (Science, 30 April 1999, p. 722). But qubits in solid state devices tend to decohere in just 10 or so nanoseconds. It's this problem that Awschalom's group set out to solve by finding a way to manipulate quantum information more quickly. For this early-stage study, however, the team didn't make qubits, which switch between two states only. Rather, they chose a simpler task of manipulating electrons that can sit in many states.

    The team—which included UCSB grad student Jay Gupta and Penn State professor Nitin Samarth and postdoc Rob Knobel—started with a semiconducting material called zinc cadmium selenide (ZnCdSe) and a laser setup designed to jockey electrons in the material. Like all electrons, those in ZnCdSe have spin, a quantum-mechanical property associated with magnetism. The spin of an electron can point in various directions, and those pointing in different directions have slightly different amounts of energy. If researchers could control the movement, they might use the different spin directions to represent bits of information.

    Normally, the spins on different electrons in ZnCdSe tend to make them wander their own way. So the group's first task was to coax them all to share the same spin, giving them a common starting point. To do that, they blasted the semiconductor with an initial 100-femtosecond pulse of circularly polarized blue light. Circularly polarized photons spiral like corkscrews as they travel. When the spiraling photons smacked electrons in the semiconductor, they gave up both their energy and their spins. The photonic barrage kicked a group of electrons in the semiconductor so that they all carried the same spin (see diagram).

    To manipulate these spins, Awschalom's group fired a second 100-femtosecond pulse, this one containing photons of blue-green light. Individually, such lower energy photons are too weak to be absorbed by the electrons in the semiconductor. But as they passed through the semiconductor, Awschalom explains, their collective presence effectively created a brief magnetic field. This field tapped the electron spins into a new orientation, much as the flick of a finger alters the precession of a spinning top. In a final step, the group used a third 100-femtosecond pulse to spot the electron spins in their new state.

    The UCSB-Penn State team's success marks the first-ever all-optical processing of electron spins in a solid. But it still falls short of being a quantum computer. To stake that claim, the researchers must clear two more hurdles. First, they must create qubits. The key to that, Awschalom says, may be creating specks of semiconductors called quantum dots, capable of trapping single electrons that can harbor spins in two directions. Then the team must learn to manipulate at least two qubits, so that changes to the state of one qubit affect the state of the second—a necessity for performing quantum computations. Each feat, say researchers, will mark a major stride on the road to quantum computing.

  5. CELL BIOLOGY

    NO Helps Make Fireflies Flash

    1. Elizabeth Pennisi

    Incandescent and fleeting, the firefly embodies sultry summer nights. Light is the firefly's language of love. Each evening, males take flight, emitting telltale flashes. From the ground or bushes, females beckon with their own bursts of light. Long the object of study, fireflies have yielded many secrets of this mating ritual. But a key step in triggering the burst of light has defied elucidation. Now, neurobiologists have identified that missing link. And much to their surprise, it turns out to depend on nitric oxide (NO)—a versatile cell-signaling molecule that our cells use to make blood vessels dilate, reports Barry Trimmer of Tufts University in Medford, Massachusetts, on page 2486.

    Neurobiologists have long known that the firefly's abdomen contains a lantern made of specialized cells, called photocytes, filled with a protein called luciferin. An enzyme called luciferase activates luciferin; oxygen then causes the protein to emit light. A nerve signal called octopamine controls the flash pattern, which varies from species to species. But how it does so has been unclear, as the nerve ending isn't in direct contact with the photocytes.

    Night light.

    Nitric oxide plays a role in enabling fireflies to brighten the evening sky.

    CREDIT: GREGORY K. SCOTT/PHOTO RESEARCHERS

    In 1998, while listening to a graduate student discuss his thesis on firefly sexual behavior, Trimmer, who studies NO in the caterpillar brain, was struck by the similarity between the cell types that control the lantern and the cells he worked with, which release NO. That summer, he and his colleagues collected fireflies from local fields. Initial biochemical tests determined that the enzyme that makes NO, nitric oxide synthetase, was both present and active in the lantern. “Elegant,” is how Shireen Davies, an integrative physiologist at the University of Glasgow in Scotland, describes the experiments.

    To show that NO is actually involved in flashing, Trimmer's team then analyzed the molecule's role in intact fireflies. When they exposed fireflies in a closed container to increasing concentrations of NO, the fireflies glowed nonstop. The researchers still didn't know, however, whether NO was working in the lantern or simply affecting the nerves that trigger the flashing. So Trimmer's team devised a way to remove the nerves going into the lantern but leave much of the abdomen intact, enabling them to test where NO was acting.

    When they added NO to this stand-alone lantern, it glowed. But when they added a chemical that sopped up NO as fast as it was produced, the flashing stopped —even when they were stimulating the lantern with the nerve signal. “That implies that NO is the mediator,” Trimmer explains.

    The arrangement of cells in the lantern provides clues about how NO likely works, he adds. The lantern consists of air ducts called trachea, whose cells are encircled by photocytes. The nerve endings from the top of the abdomen reach the tracheal cells but do not contact the photocytes. Inside each photocyte, mitochondria are clustered along the edge closest to the tracheal cells. So, Trimmer suggests, when the lantern is off, these mitochondria “are a barrier” that soaks up oxygen before it reaches luciferin.

    When it's time to flash, however, the NO concentration increases in the air-duct cells and diffuses over the mitochondria, briefly shutting down this oxygen barrier. In response, the oxygen concentration rises in the photocytes, setting off the light. Then “the lantern in and of itself turns off the NO reaction,” says William Sessa, a pharmacologist at Yale University, because, as other research has shown, light inhibits NO.

    Trimmer has yet to prove that this is how the lantern works. But to Gerd Bicker, an NO specialist at the Hannover School of Veterinary Medicine in Germany, the work stands on its own merits. “I am very pleased,” he says, “that NO appears to be involved in such an esthetical aspect of cellular communication.”

  6. ASTROPHYSICS

    'Tired-Light' Hypothesis Gets Re-Tired

    1. Charles Seife

    The “tired-light” hypothesis, mainstay of a dwindling band of contrarians who deny the big bang and its corollary, the expanding universe, has suffered a one-two punch. Observations of supernovae and of galaxies provide the best direct evidence that the universe is truly expanding and promise to shed light on the evolution of galaxies to boot.

    “The expansion is real. It's not due to an unknown physical process. That is the conclusion,” says Allan Sandage, an astrophysicist at the Carnegie Observatories in Pasadena, California, and leader of the galaxy study.

    It's a conclusion that most astronomers reached long ago. In 1929, Edwin Hubble announced that light from distant galaxies is redder than light from nearby ones. Hubble and others took the redshifts as evidence that the universe is expanding, causing distant galaxies to speed away faster than nearby ones. To an observer on Earth, they reasoned, this would appear to stretch the wavelength of their light, just as the sound of a police-car siren seems to drop in frequency as it speeds away. However, within a few months of the publication of Hubble's paper, astrophysicist Franz Zwicky came up with an alternative explanation: that galaxies' light reddens because it loses energy as it passes through space. In Zwicky's tired-light scenario, the universe doesn't expand at all. Distant galaxies are red not because they are moving, but because their light has traveled farther and gotten pooped along the way.

    Beyond the fringe.

    “Tired light”—a radical alternative to the standard expanding-universe model of the cosmos—has just failed two crucial tests.

    When experimenters first measured the cosmic microwave background more than 30 years ago, they found that the radiation was too dim to be explained by Zwicky's hypothesis. That realization relegated “tired light” firmly to the fringe of physics, but scientists still sought more direct proofs of the expansion of the cosmos.

    Two new papers provide the best direct evidence yet. The first, slated to appear in Astrophysical Journal, measures the brightening and dimming of a certain type of supernova. Thanks to Einstein's theory of relativity, if distant supernovae are speeding away from us, they will appear to flare and fade at a more leisurely pace than close-by ones. A team of scientists led by Gerson Goldhaber of the Lawrence Berkeley National Laboratory (LBNL) in Berkeley, California, has shown that this is, indeed, the case with 42 recently analyzed supernovae. “It's such a clean-looking curve,” says Saul Perlmutter, a member of the LBNL team. “It's very unambiguous.”

    In the second study, Sandage and Lori Lubin of Johns Hopkins University in Baltimore analyzed space-based measurements of the surface brightness of galaxies. Both the standard expanding-universe and the tired-light theory, they realized, agree that redshifted light should make distant galaxies look dimmer than they really are. In an expanding universe, however, time dilation and other relativistic distortions will also dim distant galaxies, making them appear much fainter than tired-light theory dictates. What's more, young stars—and thus young galaxies—tend to be considerably brighter than old ones. When that extra brightness is taken into account, the observations match expanding-universe predictions, as Lubin and Sandage will report in Astronomical Journal. For the tired-light theory to be correct, young galaxies would have to be dimmer, rather than brighter, than old ones. “There's no way to explain that,” says Lubin.

    Although not surprising in themselves, the results are useful for “tidying things up in our cosmology,” says Michael Pahre, an astronomer at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, who performed a similar surface-brightness experiment in the mid-1990s. By comparing the expanding-universe theory's predictions with observed values of the surface brightness of distant galaxies, scientists can work backward and figure out how much brighter those galaxies must have been earlier in the history of the universe.

    Even so, researchers doubt whether the results will convert tired-light diehards. “I don't think it's possible to convince people who are holding on to tired light,” says Ned Wright, an astrophysicist at the University of California, Los Angeles. “I would say it is more a problem for a psychological journal than for Science.”

  7. PARTICLE PHYSICS

    Russian Turmoil Rattles CERN

    1. Vladimir Pokrovsky,
    2. Andrey Allakhverdov*
    1. Vladimir Pokrovsky and Andrey Allakhverdov are writers in Moscow. With reporting by Richard Stone.

    MOSCOW—Discord over KGB-style rules that require Russian academics to report contacts with foreign scientists—as well as a management change at a key institute—are raising caution flags about Russia's collaboration on a major international particle physics project being built at CERN, the European laboratory for particle physics near Geneva.

    Last month, the Russian Academy of Sciences issued a directive ordering its 55,000 researchers to report any international activities and contacts to the academy's governing presidium. Some observers see the directive as a benign effort to protect researchers from inadvertently divulging classified information. Others, however, view it as a thinly veiled attempt to allow the KGB's successor agency, the Federal Security Service, to exert more control over the scientific community (Science, 8 June, p. 1810). Now, similar restrictions are roiling the waters at nonacademy institutes.

    Imperiled

    Russia's contribution to the LHC includes top minds and materials such as these lead tungstate crystals.

    CREDIT: CERN GENEVA

    At issue are rules requiring all institutes overseen by the Ministry of Atomic Energy (Minatom) to inform it about visits from foreign researchers no less than 45 days prior to their arrival. Although the rules were put in place 3 years ago, Minatom had enforced them only at sensitive facilities such as the nuclear weapons design centers in Sarov and Snezhinsk. Now, purely civilian outfits like the Institute for Theoretical and Experimental Physics (ITEP) in Moscow are under pressure to toe the line, says ITEP physicist Boris Ioffe.

    In the increasingly tense atmosphere last week ITEP director Mikhail Danilov, a key figure in Russia's delegation to CERN, tendered his resignation. When contacted by Science, Danilov declined to comment. However, some ITEP staff members assert that the resignation stems from Danilov's frustration over Minatom's recent restrictions on foreign contacts. Besides bleeding off some of Danilov's authority, the rules could put a chill on foreign collaboration, Ioffe predicts. Others insist that the administrative burden of the directorship, rather than any increased pressure from Minatom bosses, spurred Danilov's resignation. Either way, Ioffe says, “the situation is very difficult.”

    That's alarming news to CERN, which is relying heavily on Russian researchers to help build the $1.5 billion Large Hadron Collider (LHC), a machine that will explore fundamental questions such as why particles have mass. Roughly 600 Russian physicists are working on the LHC, providing an invaluable contribution to the collider and its associated experiments (Science, 13 October 2000, p. 250). About one-quarter of the Russian contingent comes from ITEP. “If, as I suspect, the security pressure will increase,” Ioffe warns, “then ITEP's contacts with CERN will shrink, and consequently ITEP's participation in CERN projects will shrink.” Others have a less dire take. “I don't see any danger for the time being,” says ITEP deputy director Vitali Kaftanov. The most important wildcard, he argues, is whether Danilov's successor will be able to convince Minatom that the CERN collaboration is worth supporting.

  8. CELL CYCLE RESEARCH

    DNA: Once Copied, Thrice Blocked

    1. R. John Davenport

    When it comes to cell division, nature demands close tolerances. A dividing cell must keep a tight rein on DNA replication to ensure that each daughter receives exactly one copy. Indeed, failure of that control and the genetic instability that results can lead to cell death or even cancer. Although more than a decade ago cell biologists identified the master protein that guarantees that DNA replication occurs only once, they don't understand how it exerts its power. Now, part of that puzzle has been solved.

    In the 28 June issue of Nature, a team led by Joachim Li of the University of California, San Francisco, reports that three separate pathways, all under the control of the master coordinator, a protein kinase known as Clb-Cdc28, must work together to prevent a second round of DNA synthesis from getting under way before the cell divides.

    The current findings are an outgrowth of work done over the last 5 years indicating that Clb-Cdc28 does double duty in controlling DNA replication. When cell division begins, a group of proteins called the prereplicative complex (pre-RC) comes together on each of the many origins of replication where DNA synthesis begins. Once assembled, the pre-RCs stand poised to initiate replication but don't do so until the cell suddenly activates the Clb-Cdc28 kinase. That's when the enzyme shows its versatility.

    Safeguard.

    Activation of the Clb-Cdc28 protein kinase triggers DNA replication (S) and acts through three targets (ORC, Cdc6, and Mcm2-7) to prevent a second round of replication. Inactivation of the kinase after mitosis (M) allows a new round of replication.

    CREDIT: ILLUSTRATION BY C. SLAYDEN

    It first triggers replication by the assembled pre-RCs, but once they fall off the origins of replication, it inhibits assembly of new pre-RCs that would reinitiate DNA synthesis. As a result, Clb-Cdc28 triggers one and only one round of replication. Then, once the cell divides, Clb-Cdc28 shuts off and new pre-RCs can assemble for the next round of cell division.

    Although the details of how Clb-Cdc28 prevents reinitiation remain sketchy, researchers over the past few years have found several potential targets through which it might prevent reassembly. As a kinase, Clb-Cdc28 has the ability to add phosphate groups to other proteins, including three components of the pre-RC. Two of these are so-called initiator proteins: Cdc6, which is targeted for degradation when phosphorylated by Clb-Cdc28, and the protein complex Mcm2-7, which is kicked out of the nucleus when thus modified. The origin recognition complex (ORC), a group of proteins that is also part of the pre-RC, harbors sequences that look like Clb-Cdc28 phosphorylation sites, but researchers haven't proved that. They have also had trouble proving that the three targets help prevent reinitiation, because separately rendering each of them immune to Clb-Cdc28's influence doesn't remove the block. That led them to postulate that all the proteins, and perhaps others, have to work together to prevent reinitiation.

    Now, Li's team has provided the experimental proof for the cooperation by making yeast cells in which all three potential targets can override regulation by Clb-Cdc28 simultaneously. The researchers did this by eliminating the potential phosphorylation sites in ORC and adding a sequence to one of the genes encoding a protein in the Mcm complex that prevents the complex from leaving the nucleus. They also put the gene for a degradation-resistant version of Cdc6 under control of an inducible promoter. That let them express Cdc6 even when Clb-Cdc28 activity is high and Cdc6 is normally degraded. The altered yeast cells could no longer block DNA rereplication. But the yeast cells didn't copy the DNA over and over again: For reasons that are currently unclear, they produced only about one genome's worth of extra DNA.

    An important implication of the result is that control of the replication trigger is separate from that of the block for pre-RC reassembly, an outcome Li deems fortunate. When he began the work, he recalls, he was concerned that, like Clb-Cdc28 itself, the targets would be needed to initiate replication, as well as to inhibit formation of the pre-RCs. If that had been the case, he says, the cells wouldn't have replicated at all and “we would have been stuck.” The fact that that wasn't the case, Li adds, indicates that there are other phosphorylation sites on those proteins or additional proteins that trigger initiation of replication.

    The results “show that there are multiple levels of control of prevention of the rereplication,” says molecular biologist Stephen Bell of the Massachusetts Institute of Technology, a finding that, he notes, emphasizes just how important that function is. Bell is also intrigued that inhibiting pre-RC assembly and triggering initiation are regulated separately. “The simplest model would have been that they were coupled, but once again the cell defies expectations.”

  9. ARCHAEOLOGY

    Unwrapping a Modern Mummy Mystery

    1. Robert Koenig

    BERN—Last October, police in Pakistan's remote province of Balochistan seized an ornately carved mummy coffin on offer to art dealers for $11 million. A golden plaque on the coffin included an Old Persian cuneiform inscription suggesting that wrapped inside were the 2600-year-old remains of a daughter of King Xerxes. But like a pulp-fiction mummy unraveling in front of horrified onlookers, the exalted Persian princess's pedigree has fallen to pieces. Indeed, the intriguing circumstances read like the plot of a dime novel. The female mummy now appears to have been a relatively recent murder victim or else a body snatched from a grave shortly after death—two grisly scenarios that have scientists digging for clues to her true identity.

    Recent analyses have shown that the artifact is a fake, but that the corpse is very real. Last week, a German team announced that it is conducting radiocarbon dating of muscle, skin, and bone snippets from the mummy to find out how long the toothless and tongueless bandage-wrapped body has been dead, which might help determine whether her broken back indicates foul play. “The mummy is clearly a fake, and this may have been a murder,” says curator Asma Ibrahim of the National Museum of Pakistan in Karachi.

    Although the discovery initially caused a sensation last fall, it wasn't long before archaeologists and others began to voice suspicions. Scientists were dubious about the cuneiform inscription, which bore a few textual mistakes. They also looked askance at the preparation of the mummy, which was not fully desiccated. “The mummy's bandages were so hard and thick, we had to use an electric drill to cut through them,” says Ibrahim, who says that genuine mummies are more easily unwrapped. Further inspections and computed tomography scans of the body, now in a Karachi mortuary, showed that the woman's back was broken and that her mouth and stomach were “full of a powder,” samples of which are now being analyzed, Ibrahim says.

    A royal hoax

    Scientists have debunked claims that this mummy was a Persian princess.

    CREDIT: NATIONAL MUSEUM OF PAKISTAN

    In a further plot twist, the Iranian Cultural Heritage Organization said last fall that it planned to take legal action to seize the mummy. The grounds: a suspicion that the mummy may have been an ancient member of the Persian royal family smuggled into Pakistan from Iran. In January, however, a delegation of Iranian experts—citing errors in the breastplate inscription and other flaws—declared it a fake. A month later, Archaeology magazine weighed in, reporting that a U.S. expert on Old Persian texts had concluded that the cuneiform on the mummy casket was likely a modern falsification lifted in part from a 520 B.C. inscription of King Darius at the Behistun site in western Iran.

    In the meantime, Ibrahim had sent samples from the coffin, the matting under the mummy, and the bandages and resins to Pakistani experts and to the German Archaeological Institute in Berlin for analyses. The Pakistan Atomic Energy Commission's laboratory agreed to stray outside its bailiwick to radiocarbon date some of the materials. “We wanted to get Pakistani scientists involved,” says Ibrahim, who in April issued a report finding that the materials were of recent origin and concluding that the mummy is a fake.

    Ibrahim says that recent tomography scans and other analyses indicate that the body—whose bones show signs of osteoporosis—is that of a woman older than 50 who died probably within the past 5 or 6 years. However, to chase Ibrahim's hunch that the mummy is a murder victim or was dug up by grave robbers shortly after it was interred, Pakistani detectives would need a better idea of the time and place of death.

    The detective assignment is being taken on by physicist Gerhard Morgenroth, who says his lab at the Friedrich Alexander University of Erlangen-Nuremberg, Germany, is working “to give as exact a time frame as possible” for the woman's death. Earlier this year, the German Archaeological Institute in Berlin sent Morgenroth samples of cloth and matting from the coffin. He has dated them using accelerator mass spectroscopy, which detects minuscule concentrations of elements. This spring, Morgenroth's tests determined that the fabric “could not be more than about 40 years old,” as it contains traces of radioactive isotopes from nuclear-weapons tests carried out between either 1958 and 1960 or 1992 and 1994. The BBC, which is preparing a documentary, has commissioned Morgenroth to carry out such tests on the mummy's tissue samples. These tests, now nearing completion, should be able “to date the mummy's time of death to within 2 or 3 years,” he says. But they can't place where the woman died. Meanwhile, Ibrahim fears that a ring of mummy-fakers may try to produce and sell similarly false artifacts.

    If there's a lesson to be learned, Ibrahim says, it's that it pays to scratch below the surface of any archaeological claim. “The wooden coffin was beautiful and very convincing, so the flaws were not obvious at first,” she says. Now Ibrahim would like to see the mystery solved—and those who perpetrated the hoax brought to justice.

  10. ARCHAEOLOGY

    Writing Gets a Rewrite

    1. Andrew Lawler

    Recent discoveries in the Near East and Pakistan are forcing scholars to reconsider traditional ideas about writing's evolution. But a lack of fresh data is making their task difficult

    BAGHDAD—The inventor of writing, according to Mesopotamian legend, was a high priest from the great city of Uruk who one day began making marks on wet clay. Five thousand years later, German archaeologists triumphantly discovered the oldest examples of writing—called cuneiform—200 kilometers south of here in a long-buried Uruk temple, providing what seemed to be scientific confirmation of the ancient myth.

    But that heroic story is quietly being shelved by scholars as new finds in Egypt and Pakistan over the past decade, and a radical reinterpretation of clay objects found in Mesopotamia's heartland and its periphery—today's Iraq, Syria, and Iran—have necessitated a different account. Most researchers now agree that writing is less the invention of a single talented individual than the result of a complex evolutionary process stretching back thousands of years before the first hard evidence of writing surfaced in Mesopotamia, Egypt, and the Indus River valley about 3300 B.C. “The prehistoric communication revolution began some 9000 years ago,” says Joan Oates, an archaeologist at the University of Cambridge, U.K., who spoke at a recent conference here* “In a sense, writing appears as the last step in the long line of evolution of communication systems.”

    Abydos

    Early writing found in Egypt. Scholars agree that the findings led to hieroglyphs but disagree over this system's sophistication.

    Uruk

    An example of protocuneiform, which developed before 3000 B.C. in Uruk. Accurately dating these early tablets has proved problematic.

    Harappa

    Indus River script developed far earlier than once believed; this sample found in Pakistan dates to before 3000 B.C.

    CREDITS: (TOP TO BOTTOM) DAI-BAGHDAD; GUNTHER DREYER;HARAPPA ARCHAEOLOGICAL RESEARCH PROJECT

    The revised text on writing's history, however, is far from complete. Scholars say they are hampered by a lack of fresh data from Near Eastern sites, the reluctance of museum curators to allow potentially destructive testing of critical artifacts, and the limitations of radiocarbon dating. Moreover, the 1989 discovery in Egypt of an ancient and sophisticated writing system has fueled a new debate: Did Mesopotamia's literacy trigger that of Egypt, as is traditionally supposed, or was it the other way around—or neither? More recent finds showing that the Indus script likely was evolving around 3300 B.C.—at about the same time as its Near East counterparts began to coalesce—have deepened the mystery. Some researchers, pondering the near-simultaneous appearance of seemingly separate protowriting systems in three distinct civilizations, suggest that they may have developed independently in response to similar circumstances.

    But tracing the predecessors of cuneiform, hieroglyphics, and Indus River valley script becomes increasingly tricky the farther back in prehistory researchers probe. “We really have very little information prior to 3500 B.C.,” says Piotr Michalowski, a cuneiform scholar at the University of Michigan, Ann Arbor. “It comes down to a matter of faith.”

    Token theory

    For decades, archaeologists in Iraq, Syria, and Iran dug up curious ceramic pieces—numerous small tokens in diverse geometric shapes. They also found hollow clay spheres with markings on the outside from later periods and with these same small ceramic pieces inside. Those ranged in age from about 9000 to 4000 years old but were dismissed by most researchers as ancient games and relegated to museum storage bins.

    But Pierre Amiet, an archaeologist at the Louvre in Paris, suspected as early as the 1960s that the mysterious objects were actually used to count goods. Since then, his student Denise Schmandt-Besserat, now at the University of Texas, Austin, has elaborated on that theory. After studying thousands of tokens, she proposed in the 1980s that different shapes signified different commercial objects—a cone shape, for example, represented a measure of grain; a cylinder connoted an animal. The number of tokens indicated quantity. “It was the first visual code, the first system of artifacts created for the sole purpose of communicating information,” she says.

    Despite her colleagues' skepticism, Schmandt-Besserat went on to theorize that the system grew and evolved over thousands of years. By the end of the fourth millennium B.C., tokens represented different animals; processed foods such as oil, trussed ducks, or bread; and manufactured and imported goods such as textiles and metal, she says. By about 3500 B.C., concurrent with the growth of major cities like Uruk, the tokens were often found in hollow clay spheres, like envelopes; markings on the outside indicated the sorts and quantities of tokens within.

    Ultimately, the tokens were dispensed with altogether, and the clay spheres became clay tablets with impressed marks representing objects—marks that evolved into early cuneiform, according to Schmandt-Besserat. By 3100 B.C., someone—perhaps indeed an Uruk priest—began to use a reed stylus on wet clay to make the more precise markings that comprise cuneiform. This form of writing continued at Uruk and other Mesopotamian sites until the latter days of the Roman Empire, much as Latin survived as an elite and holy language in Europe for more than 1000 years after Rome's fall.

    The token theory, according to some scholars, helps solve a nagging puzzle. “The great mystery until now was how a full-fledged system emerged so suddenly,” says William Hallo, an Assyriologist at Yale University. “Now we can see a progression of successive steps [over] a fairly extended time.”

    But many Assyriologists say Schmandt-Besserat goes too far in postulating a sophisticated representational system before 3500 B.C. Oates prefers to call the tokens “a means of remembering rather than a genuine recording device.” Eleanor Robson, an Assyriologist at Oxford University, U.K., says the later arrangements of tokens in spheres clearly are “a coherent system”; even so, she says, it is hard to identify the inside objects definitively from before 3500 B.C. “Most are little blobby lumps,” she says, “and it's hard to know which are tokens and which are beads or weights.”

    Old times.

    Gunther Dreyer found ancient writing in Egypt that may predate cuneiform.

    CREDIT: COURTESY OF GUNTHER DREYER

    Skeptics also insist that there is little evidence that cuneiform grew directly out of this system, as Schmandt-Besserat maintains. Token shapes and the impressions made on the spheres, she says, inspired cuneiform's representations for objects such as sheep and oil. But others are not so sure. “I accept the tokens as the earliest form of writing, but I see no good evidence that incised tokens are precursors” to cuneiform, says Robert Englund, a Sumerian scholar at the University of California, Los Angeles. Paul Zimansky, a Boston University archaeologist, agrees. “There's no indication of linkage,” he says.

    A few scholars take a harder line. Michalowski holds to the idea that cuneiform is a separate development that may have been influenced by tokens and cylinder seals—also widely used in ancient Mesopotamia—but that is unique and distinct. “I joke that cuneiform had to be invented by one person because it was too good to be invented by a committee,” he says, arguing that the system is the result of a “quantum leap” that drew on many traditions.

    More data would clearly be welcome. Englund and Robson assert that more research should be done on the sealed hollow spheres, more than 100 of which are in museums around the world. Englund and his colleagues have already done x-rays and computerized tomography scans on these objects at the University of Heidelberg in Germany, but, they say, the time, expense, and low resolution of these procedures make them a poor substitute for splitting open the spheres and studying them directly. Curators, however, are reluctant to see their artifacts tampered with and possibly destroyed. “It's an unpleasant situation,” Englund says.

    Dating troubles

    Egypt is only 1000 kilometers west of Mesopotamia, and there is a long history of trade between the two great civilizations. So scholars have long accepted the idea that hieroglyphics—which were thought to have appeared a century or so after cuneiform—were inspired by the Uruk concept of storing information.

    But a 1989 discovery by Gunther Dreyer of Cairo's German Archeological Institute and his subsequent findings at Abydos in upper Egypt have threatened Mesopotamia's ancient claim as the source of the first writing system. Opening a royal tomb dubbed U-j in 1989, Dreyer's team found a large trove of objects bearing inscriptions that are more than a century older than the oldest written materials previously discovered in Egypt. The finds, which include nearly 200 small bone and ivory objects, are from roughly the same era as Uruk's earliest tablets—around 3200 B.C. A rougher set of similar inscriptions was found on nearby vessels. About 50 signs seem to represent humans, animals, and a palace façade. Later findings nearby included pot marks dating to about 3500 B.C.

    Dreyer argues that the symbols represent a single well-developed system that led to hieroglyphics. But other researchers are skeptical of this claim. “The pot marks can't be interpreted,” and so the data “are insufficient” to draw wide-ranging conclusions, says John Baines, an Egyptologist at Oxford University, although he agrees that the inscriptions on bone and ivory clearly are writing.

    Code breaker?

    Denise Schmandt-Besserat maintains that clay tokens and spheres led to cuneiform.

    CREDIT: COURTESY OF DENISE SCHMANDT-BESSERAT

    Meanwhile, attempts to accurately date materials from both Egypt and Mesopotamia have proven inconclusive. Recent radiocarbon dating in Heidelberg of charcoal from both an Uruk temple, where early cuneiform tablets were found, and the Abydos tomb showed a date of approximately 3450 B.C. for Uruk and 3320 B.C. for Abydos—pushing back the previous dates, based on well-known Egyptian chronologies, about 150 years.

    Margarete van Ess of Berlin's German Archeological Institute, for one, accepts those dates, which push the origin of cuneiform back by a century or so, giving Mesopotamia the edge. But other scholars say such precision is not possible in radiocarbon dating. Researchers are looking for additional clues, both in situ and on the tablets and vessels that record the early writing; Van Ess, for example, recently began digging at Uruk after the decade-long hiatus resulting from international sanctions against Iraq.

    Those clues are hard to come by, however. Because builders at Uruk often used old tablets as fill, pinpointing their date and context is difficult. “Uruk is such a mess,” says Englund. “The stratigraphic record is really quite horrible.” And Dreyer—who continues his excavations—has yet to find significant material at Abydos that may shed more light on hieroglyphic evolution.

    Three at once?

    Archaeologists in Pakistan have had more luck in recent years. A team of U.S. researchers discovered compelling evidence in the late 1990s that the script from the Indus River valley also has a long and complex history. The Harappan civilization flourished there from 2800 B.C. to 1700 B.C. before collapsing; its script ceased to be used afterward, and the meanings of the signs remain a mystery. But although it never attained the complexity of the Mesopotamian or Egyptian writing systems, the Indus script nevertheless developed into a formidable grouping of signs.

    The recent finds suggest that the script arose more than half a millennium earlier than previously believed. Pottery discovered at the site of Harappa includes markings that date from 3500 B.C. to 3300 B.C. and that appear to be precursors to that script. “I wouldn't call these signs writing,” says Richard Meadow, a Harvard archaeologist who works at the site. “But these could be seen as part of an evolution of signs that continue to the Harappan period.”

    The Harappan and Abydos finds pose a major challenge to the traditional theory that writing diffused gradually from Mesopotamia to Egypt and perhaps to the Indus. All three areas were linked by trade in prehistory—Egypt to Mesopotamia through the Levant, and Mesopotamia to the Indus through modern-day Iran and the Persian Gulf coast. But the dominance of Mesopotamia is now in question.

    “That the idea [of writing] passed from Egypt to Mesopotamia is quite a possibility now,” maintains Dreyer. Others are not so quick to make that leap. “I'm undecided,” says Baines, “but I don't think that's likely.” Still other Mesopotamian scholars largely adhere to the old school of east-to-west influence, given what they say is the long evolution apparent from cylinder seals and the clay spheres.

    Baines, however, posits a third possibility: that the two systems developed independently at about the same time. And if Harappa is included, then the evidence suggests that three separate systems with their own evolutionary paths began to mature nearly simultaneously. That would appear a stunning coincidence, but some researchers say contact with other groups, combined with an indigenous need to convey more complex information, might have been the not-so-coincidental common ingredients that made the Near East and the Indus advance so quickly.

    “Writing develops in areas where people are interacting,” says Jonathan Kenoyer, an archaeologist at the University of Wisconsin, Madison, who has dug along the Indus. “Yet these regions also developed their own unique forms of expression.” This is true not only for the scripts, which are unrelated, but also for their function. In Egypt, for example, writing typically was focused on ceremonial uses, while accounting dominated Mesopotamian tablets.

    However writing matured, scholars are left with the more daunting mystery of who laid the foundation for the artisans at Abydos, priests at Uruk, and the unknown makers of Indus script. “No one expected writing had such deep roots in prehistory,” says Schmandt-Besserat. Deciphering that long and complex story is proving a formidable and controversial task, with no Rosetta Stone in sight.

    • *International Conference of the Fifth Millennia of Writing, Baghdad, 20–26 March.

  11. PROFILE

    Dollars and Cents vs. the AIDS Epidemic

    1. Gretchen Vogel

    An atypical economist is a driving force behind the new global health fund being debated this week at a special session of the United Nations

    BOSTON—Jeffrey Sachs is in his office for the first time in 3 weeks—and he is here today only because a trip was canceled at the last minute. He will be here for 2 days before taking off again for meetings in Asia. Hundreds of e-mails are crying out for his attention, the accumulation of just a few days, and his telephones—including his ever-present cell phone—never seem to stop ringing. This Harvard economist is clearly no run-of-the-mill academic.

    Sachs is in demand—and constantly in the public spotlight—because he has jumped into one of the biggest and most visible international public health issues of the day: the tragedy inflicted by HIV/AIDS on the developing world, especially sub-Saharan Africa. He's become one of the most vocal advocates for a multibillion-dollar international program to tackle not only AIDS but the intolerable disease burden that, he argues, is holding back the developing world. He's constantly cajoling rich governments to open up their coffers and drug companies to loosen their intellectual property claims on drugs desperately needed in poorer countries.

    But it's not just his cause that has made him visible. It's also his style. He recently teamed up with an international crew including Pope John Paul II and rock star Bono, U2's lead singer, to campaign for debt forgiveness in poor countries. The money, he says, could be better spent on health. A great fan of U2, Sachs spends about as much time on the road as the band does, some 25 days a month if he isn't teaching. And like Bono, Sachs can bring crowds to their feet—in his case with impassioned sermons on the rich world's obligation to drastically increase spending on public health in poor countries. “Jeff shakes up the world,” says Harvard colleague Barry Bloom, dean of the School of Public Health. “He's not known for his interest in balance and moderation.”

    Indeed, his demands are rarely restrained. His latest campaign is to persuade wealthy governments to donate $10 billion to a global health fund that would fight malaria, tuberculosis, and HIV/AIDS. From a macroeconomic perspective, he explains, $10 billion is not a lot of money: just four-hundredths of a percent of the rich countries' yearly income and only $10 for each of the 1 billion people who live in wealthy countries. And what it could buy is immeasurable: By relieving the disease burden in poor countries, the fund could be a fundamental tool to jump-start development.

    Sachs is just one of several powerful voices—including Secretary-General of the United Nations Kofi Annan—advocating for the fund, but his credentials as a topflight economist have helped bring the argument into the mainstream. “Economists have a lot more weight with politicians than anyone in health could have,” says epidemiologist and veteran public health expert William Foege of Emory University in Atlanta and chief adviser to the Bill and Melinda Gates Foundation in Seattle. “All one has to do is look at an average newspaper and see what proportion of it is dedicated to economics to understand how he has had an impact.”

    Whether or not Sachs should get the credit, the global fund is beginning to take off. In April, U.S. President George W. Bush pledged $200 million to the fund; in the last month, several more pledges have trickled in, including $100 million from the Gates Foundation, $100 million from the United Kingdom, and $127 million from France. As Science went to press, delegates at the United Nations Special Session on HIV/AIDS were beginning to hammer out how the fund would be organized.

    No shrinking violet

    Notoriety came early to Sachs. At the ripe age of 28, just 3 years after earning his Ph.D. in economics from Harvard in 1980, Sachs, now 46, became the youngest professor ever to win tenure there. (He shared that honor with fellow economist and incoming Harvard president Lawrence Summers.) It didn't take long before Sachs was making international headlines as an adviser to governments in Latin America and Eastern Europe. In Bolivia he helped to stem runaway inflation and restructure that country's international debt. In Poland, he advised Lech Walesa during the transition to a market economy, prescribing “shock therapy”—an abrupt end to price supports and trade barriers. “Probably the most important economist in the world,” was how The New York Times Magazine once described him; “the world's best-known economist,” according to Time in 1994.

    But he had his detractors within the economics profession. In the early 1990s, he advised Russian President Boris Yeltsin to give the Russian economy the same shock therapy, but the country subsequently went into a tailspin. He was widely criticized by his colleagues, who said the therapy was too harsh and blamed it for the crushing difficulties (including the collapse of the public health system) Russia endured as it struggled to convert to a market economy.

    Fresh from that setback, Sachs, who became head of Harvard's Institute for International Development in 1995, began to explore the unconventional ideas that now dominate his work—bringing together the disparate worlds of macroeconomics and public health policy. He didn't experience an epiphany, he says, but he came to a gradual realization of the limits of open markets and sound fiscal policy. A decade after he helped Bolivia back to its feet, it was clear that a stable economy was not enough. The country “still remained in a lot of trouble economically,” he recalls. Similarly, he says, many supposedly stable African countries were failing to achieve macroeconomic growth.

    Sachs returned to an old puzzle of macroeconomics: Why do tropical regions tend to be poorer than temperate ones? And as he worked in those regions, especially in Africa, he found disease staring him in the face. “More and more it grew on me as a fundamental part of the explanation of economic performance,” he says. Chronic, energy-sapping malnutrition, as well as malaria and other infectious diseases, cause children to lag behind in school or drop out completely and limit the productivity of farmers and businesspeople alike.

    In 1998, Sachs became director of the newly formed Center for International Development at Harvard. That year, with colleague John Gallup, he published an analysis of the effect of malaria on economic development. After taking into account factors such as geographical location, colonial history, and economic policy, they concluded that countries with severe malaria (in which roughly half the population is at risk of contracting the Plasmodium falciparum parasite) had one-third the income levels of equivalent countries without malaria—and a 1.3% lower growth rate per year. Malaria “has had a stranglehold on development in many parts of the world,” he says. While that idea is still debated by macroeconomists—not everyone is convinced that the paper demonstrated cause and effect—it definitely rocked the development community.

    The notion that health plays a role in economic success was not entirely new, says economist Michael Kremer of Harvard University and the Brookings Institution. But few economists had it at the top of the list, he says. That is reflected in funding for global health efforts—the U.S. Agency for International Development, for instance, spent more than twice as much on economic programs as on health in 1998.

    “Jeffrey Sachs was one of the first who understood the impact of tropical diseases on development,” says Hans Binswanger, an economist at the World Bank in Washington, D.C.

    A global awakening

    As Sachs immersed himself in public health, he was struck by how little money or scientific effort rich countries devote to tropical diseases, which claim millions of lives each year—a deficit that relentlessly widens the gap between rich and poor, he says. Almost as disturbing was the paltry support for African scientists. “I've met wonderful scientists—deans of medical schools, long-practicing clinicians—who have no resources,” he says. “I meet unemployed or underemployed malariologists of tremendous skill all over Africa. … They have wonderful suggestions about what to do, and they can't get anyone's attention.”

    As a neophyte in this world, “I was quite shocked,” Sachs recalls. “I was not aware of how incredibly impoverished the global public health system was. I learned what other people knew, but … the numbers mean something different to me as a macroeconomist than they do to a public health official. Many times I had to shake public health officials and say, ‘Millions are not enough. This is a matter of billions of dollars at the minimum. And don't be shy of the billions, because that's what the macroeconomic world is all about right now—and public heath is getting unbelievably short shrift compared to the urgency of the issues.'”

    In hundreds of papers, Op-Eds, speeches, and behind-the-scenes meetings, Sachs has been working to bridge that gap, exhorting, cajoling, and shaming leaders of rich countries and donor agencies to support public health efforts in poor countries. And he is not shy about asking for billions. That's what is needed, he says, to deliver the drugs that can help stem the global AIDS epidemic. “Like many, Sachs came late to the AIDS issue, but when he took it on, he really took it on with a vengeance,” says Binswanger.

    Sachs sees the AIDS 2000 meeting in Durban in July last year as a turning point. Speaker after speaker reported that life-extending drugs are transforming the specter of AIDS in rich countries. At the same time, it was painfully clear that those drugs “reach almost nobody in poor countries—and that our world must not go on like that,” Sachs says. “The notion that parents should be sent to their graves for lack of $500 a year in drugs strikes me as a mind-boggling miscalculation from an economic development point of view as well as being immoral.”

    One year later, “we're still without officially supported treatment programs,” says Sachs. But although he is impatient, he sees progress. “It is now widely if not universally accepted that treatments should be part of official policy.”

    On the ground

    Not only have governments recognized the need for treatment, says Sachs, but drug companies have responded to pressure from both the public and generic-drug manufacturers. The big AIDS drug companies have agreed to reduce their prices in developing countries or allow generic versions to be used, so that it is now feasible to think about treating an entire continent. “That is a real breakthrough,” he says.

    Treating millions of HIV-infected individuals in poor communities is easier said than done, but Sachs believes that with support from science, it is possible. In a “consensus statement” released in April, 128 professors from Harvard's medical school, school of public health, and other departments called for a series of intensive clinical trials to determine the most effective use of antiretroviral therapy in the developing world. That statement, spearheaded by Sachs, pointed to the success of small-scale use of “directly observed therapy” or DOTs—when a public health worker watches a patient take the necessary drugs—first used for treating tuberculosis. Scientific input and review of projects, similar to study sections at the National Institutes of Health, is critically important—and is something many past efforts have lacked, says Sachs. “There has been a tremendous amount of amateurism and seat-of-the-pants operations by donor agencies. Somehow proper science just doesn't get into the story.”

    Although Sachs is not lacking in confidence, many in the AIDS and development communities are skeptical. Some worry that an overemphasis on treatment will drain already scarce funds from prevention programs—the only way to slow the epidemic. “Jeff Sachs's view is that money is not scarce. But that has yet to be demonstrated in the real world,” says senior economist Mead Over of the World Bank in Washington, D.C. And if they had to choose between prevention and treatment, many say prevention would save the most lives.

    But Sachs argues that prevention will ultimately fail without treatment programs. “I'm utterly convinced that people will not get tested, will not consider themselves infected, if this is not put in a medical context,” he says.

    Bloom agrees. “I see the drugs as a catalyst that has caused a major change in people's thinking in what is possible and what is not possible,” he says. Sachs's call for treatment “has opened a flood of possibilities that would not have come from prevention alone. People are not going to put $5 billion a year into condoms.”

    As pledges to the global fund accumulate, Sachs is increasingly optimistic and steadfast against naysayers. “Will rich countries actually be persuaded? Not if ‘experts' say that it is impossible. The key, I believe, is to show the need, the feasibility, the enormous social benefits—and the enormous worldwide costs of doing nothing. I would advise the critics to learn a little about how large our economy really is, and how easily we could mobilize $10 billion per year from rich countries, if we decide to do so.”

  12. ECOLOGY

    Dammed If You Do, Damned If You Don't?

    1. John Pickrell

    Battle lines are being drawn over the United Kingdom's first large- mammal reintroduction, the return of the European beaver

    CAMBRIDGE, U.K.—Like many other regions throughout Europe, the spindly pine and birch forests of the loch-studded Scottish Highlands are haunted by the ghosts of charismatic species that gambol there no more. Wolves and brown bears, reindeer and lynx, wild boars and beavers all once thrived on the British Isles before humans extirpated them over the past few millennia. “There has been a sad decline in the [large] British mammalian fauna,” says Martyn Gorman, a mammalogist at Aberdeen University. “We have a moral obligation to reintroduce these species wherever possible,” he argues.

    Not everyone agrees, however, and a major test of wills is shaping up over plans for the U.K.'s first large-mammal reintroduction: the European beaver (Castor fiber). Backers view bringing back the riparian engineer as a chance for Britain to get with the continental European mainstream and to put right a historical wrong. Critics, however, contend that in the 4 centuries since the beaver disappeared from the British Isles, its former habitat has become so degraded that it would be foolhardy to resurrect the species now. Forces aligned against the reintroduction have won an extra year to press their case: Scottish National Heritage (SNH), which is leading the bring-back-the-beaver movement, announced last month that it has postponed essential survey work on beaver habitat until next spring because of the foot-and-mouth disease crisis.

    It's unclear exactly when the last beaver chewed up a British hardwood. Fossils of the beast, as well as remains of characteristically gnawed birch stumps from peat bogs in eastern England, are scattered across the island, and medieval writings mention the critter in hunting legislation and fur export tariffs. The beaver disappeared from such documentation in the British Isles around the 16th century; it lives on only in such village names as Bevere (Beaver Place) in Worcestershire and Beverly (Beaver Clearing) in Yorkshire.

    Moral imperative?

    Some argue that humans ought to bring the beaver back to atone for its extirpation.

    CREDIT: HANS REINHARD/OKAPIA/PHOTO RESEARCHERS

    The commodification of the beaver was not unique to Great Britain. Across the continent, Europe's largest rodent was trapped for its pelt, for food, and for its castoreum, musk used in medicines and perfumes. Deforestation also played a role in snuffing out the creature, which by the turn of the 20th century had disappeared from Europe with the exception of about 1200 individuals in ghettos in the lower Rhone in France, along the Elbe in Germany, in the Dnepr River Basin in Belarus, in the Voronezh region in Russia, and in southern Norway.

    Over the last several decades, 22 countries have reintroduced the beaver (see map), generally encountering little opposition. Today an estimated 400,000 beavers thrive in river basins from Saint-Tropez to Helsinki. Several European countries have also reintroduced lynx, wolves, and boar.

    The United Kingdom has been slow to embrace such reintroductions. “We have been very timid,” says Derek Yalden, a mammalogist at the University of Manchester. A beaver reintroduction was first raised as a possibility a half-century ago, Yalden says, but the idea didn't gain momentum until 1992. That's when the European Union set forth its Habitats Directive, requiring member states to consider reintroducing lost species that were once native and are now threatened elsewhere.

    One immediate task was to determine which living beavers most closely resemble the British ones of yore. After a statistical analysis of fossilized skulls and jawbones of British beavers and modern European beavers, Paul Kitchener, curator of mammals at the Scottish National Museums, found last year that the extinct British beavers most closely resembled contemporary Scandinavian populations. “The two groups share a common ancestor more recently than with other European beavers,” he says.

    With more riparian wildlands than its southern neighbor, Scotland was the obvious place to look for surviving beaver habitat, says SNH science chief Colin Galbraith, who points out that Scotland decided to pursue the reintroduction independently of England and Wales. Since taking up the beaver's cause 6 years ago, SNH has amassed a data trove indicating that sustainable beaver populations will indeed have enough habitat to survive, and that the animal will not degrade ecosystems.

    One pervasive fear is that beavers will dent Scotland's logging industry, which primarily exploits the nation's coniferous forests. But SNH-sponsored studies suggest that this is a red herring. “When we looked into this, the consensus was that conifers actually form a very small part of the beaver's diet, which is principally made up of herbs and deciduous trees,” says Peter Reynolds, a consultant for the Capreolus Wildlife Consultancy in East Lothian. Indeed, Reynolds, who reviewed the likely ecological impacts of beavers on behalf of SNH, found that British woodlands could benefit from the habitat engineers. By continually trimming trees, beavers improve conditions for understory plants, creating a more ecologically diverse habitat. And with memories still fresh of the pervasive flooding across Britain last year, Reynolds is eager to point out that European beavers are much less likely to construct dams than their North American cousins. They mostly burrow along the water's edge, he says.

    SNH also points out that it has public opinion on its side: In 1998, Scott Porter Research and Marketing of Edinburgh found that 86% of more than 2000 Scots polled were in favor of the reintroduction.

    On the comeback trail.

    From remnant populations in five countries, the European beaver has since found new homes across the continent.

    Although a seeming minority, opponents contend that the beaver could push stressed habitats past the breaking point. Deer populations have skyrocketed in recent years, taxing Scottish woodlands. “Many [riverbanks] are overgrazed and can't take any more degradation,” asserts Jane Wright, president of the Scottish Anglers National Association. Beaver-induced erosion of riverbanks could make rivers shallower and perhaps unsuitable for salmon, the mainstay of Scottish anglers.

    The iconic status of Scottish salmon is not lost on SNH, which defends the reintroduction by pointing to Scandinavia. “The top salmon rivers in Norway have beavers on them, and this doesn't harm the salmon interests,” says SNH spokesperson George Anderson. “European beaver and salmon evolved together on Scotland's rivers, and there should be no problem,” he insists.

    SNH plans to put its arguments to the test in a pilot study. The organization has set its sights on the Knapdale forest in Argyll, in western Scotland. Owned by the U.K. Forestry Commission, Knapdale's mixed deciduous-coniferous forest and lakes are “perfect beaver country,” says Anderson. The site's geography—it sits on a peninsula—would help prevent the beavers from invading neighboring countryside, but as a safety net the animals would be radio-tagged and captured if they stray too far.

    Plans to jet in three families of Norwegian beavers, about 18 individuals, for a period of quarantine were set to go ahead this summer, for release in Knapdale in spring 2002. But the foot-and-mouth epidemic has put the kibosh on all fieldwork across Scotland this year, delaying habitat surveys.

    The SNH board will meet later this summer to review the project one last time before applying to the Scottish Executive for a license to reintroduce the beaver as a non-native species. Five years after scrutinizing the beaver population's vitality and its environmental impact, the SNH would deliver a report to the Executive outlining recommendations on a broader reintroduction. If the beavers were to lay waste to Knapdale, Galbraith says, the SNH would admit defeat and scrap its reintroduction plans. Even if the beaver lives in harmony with other Scottish denizens, however, that might not usher in an era of reintroduction enlightenment. “Public acceptability is the most important thing,” says Galbraith. “I doubt there would be the same enthusiasm for [species] such as the wolf or lynx.”

  13. EUROPEAN RESEARCH AREA

    E.U. Research Chief's Strategy: Unite and Conquer

    1. Robert Koenig

    To mixed reviews, Philippe Busquin is striving to integrate European research to put it on an even footing with the U.S.

    BRUSSELS—With his nerdish spectacles and benign demeanor, European Union (E.U.) research commissioner Philippe Busquin hardly looks like a rabble-rouser. But the Belgian socialist is trying to foment a revolution in Europe's scientific community under the banner of the “European Research Area” (ERA)—a sprawling effort to better coordinate the continent's rich but scattered scientific strongholds. The ERA hopes “to overcome the fragmentation of Europe's research effort,” Busquin told Science in a wide-ranging interview earlier this month. “Within Europe, we want to catalyze research collaborations and forge stronger links between the main players.” Looking beyond the continent, he says, “the goal is to reach critical mass in R&D so that we can be an equal partner with the U.S. and international research giants.”

    Busquin's relentless campaign to forge research links across Europe has won some influential converts. European Science Foundation president Reinder van Duinen, for one, calls the ERA “a concept whose time has come.” But others question whether Busquin's pan-European research vision will ever be more than a pipe dream, and they worry that the multilateral projects his office stimulates will relegate smaller players, from Austria to Slovenia, to the sidelines.

    Under the ERA banner, Busquin's team at the research directorate's headquarters on the Square de Meeus has rolled out a series of initiatives in recent months. The ERA's central instrument is the next 4-year E.U. research program, Framework 6 (FP6), which would nurture big-ticket collaborations and double the funding for researchers to country-hop (Science, 2 March, p. 1676). In spring Busquin sent the proposed FP6 budget to the European Parliament, where it is likely to be massaged in debate this fall.

    After the major FP6 campaign came initiatives on coordinating European cancer and aerospace research; solidifying the continent's genomics research by arranging more funding for the European Bioinformatics Institute (Science, 18 May, p. 1275) and the European Mouse Mutant Archive (Science, 15 June, p. 1985); and helping form the European Governmental Research Organizations forum to bring together leaders of seven major research labs, from the CERN particle physics center to the European Molecular Biology Laboratory. The forum is an obvious step that could have been made sooner, Busquin notes: “I was surprised that the leaders of Europe's biggest international research organizations never got together.”

    Wide-angle vision.

    Busquin's idea of a European Research Area will be put to the test over the coming weeks.

    CREDIT: R. KOENIG

    Busquin studied physics before entering Belgian politics, but he likes to express his research commissioner role (a post he has held since September 1999) in chemical terms: as a catalyst. That's because FP6—which would shell out roughly $16.2 billion from 2003 to 2006—will represent only 2% of Europe's total research spending. Mobility is another Busquin buzzword; FP6 would double (to nearly $1.7 billion) the funds for programs to encourage researchers to move from lab to lab within Europe. “Sometimes it's easier for a researcher to go from Madrid to Boston than it is to go from Madrid to Sweden,” he says.

    Although Busquin promotes European unity, some disunity about his approach was likely to emerge at a meeting of Europe's research ministers earlier this week. Germany's research chief, Edelgard Bulmahn, told Science that FP6 “is heading in the right direction … to change the course of European research.” However, her Swedish counterpart, Thomas Östros, worries that the draft is too stingy for basic researchers.

    Another critic is the European Life Scientist Organization (ELSO), whose leader, Kai Simons—director of the Max Planck Institute of Molecular Cell Biology and Genetics in Dresden—argues that FP6 wouldn't do enough to help young scientists launch their careers. Busquin points out that the Framework proposal would double funding for the E.U.'s Marie Curie Fellowships, which give grants for postdocs to spend time in a lab in another European country. But Simons contends that the biggest problems come later, when young scientists are ready to move into independent research. In most European countries, he says, there aren't enough positions, so many talented young researchers flee to North American labs. To remedy that problem, ELSO is lobbying for a new “Career Development Award” that would help advanced postdocs set up independent teams. “No amount of structuring, coordination, or large-scale targeted research will make up for an absence on the ground of highly trained, well-funded, and unfettered researchers,” Simons says.

    A different set of concerns comes from scientists in central and eastern European countries—several of which are candidates for E.U. membership but already pay to play in the current Framework. They worry that the FP6 draft's emphasis on big science and country-spanning projects may leave some of their best labs out in the cold. “We understand that better integrating European science is important,” says neuroscientist Josef Syka, president of the Grant Agency of the Czech Republic. “But small countries worry about being forgotten in the process.”

    Syka and other representatives of candidate countries were scheduled to meet earlier this week with E.U. officials to discuss their concerns. Busquin says he is confident that the new Framework will benefit eastern Europe. “I know there are some problems,” he says. But candidate countries “will not be forgotten.”

    If the FP6 passes muster with research ministries and the European Parliament next year, Busquin hopes that the ERA “will help make European research more competitive and more attractive” for researchers worldwide. “My goal is for European science to be the world's best. We have the intellectual capacity, strong economies, and a good social system.” Now all that Europe needs, he says, is some cohesion.

  14. AMERICAN ASTRONOMICAL SOCIETY MEETING

    Dust Disks and Black Holes Swell the Cosmic Census

    1. Mark Sincell*
    1. Mark Sincell writes from Houston.

    PASADENA, CALIFORNIA—A surprisingly large crowd of 1400 astronomers turned out for the usually quiet springtime meeting of the American Astronomical Society, held here on 3 to 7 June. Apart from the California sun, celestial attractions included a plethora of middleweight black holes and the first discovery of a near twin of our solar system's asteroid belt.

    Midsized Black Holes Galore

    Like the glint of diamonds in the dust, brilliant pinpricks of x-rays have led three independent teams to a precious discovery: nearly 100 surprisingly heavy black holes in nearby galaxies. A handful of similar objects had been seen before, but the teams never expected to find so many more. They suggest that these so-called intermediate mass black holes could coalesce to form the supermassive black holes thought to inhabit nearly every galaxy. Black holes once seemed to come in two drastically different varieties. Those in the Milky Way and nearby galaxies had about the same mass as the sun; the rest were at least a million times heavier and lived in galaxies at the distant fringes of the universe. In between, there was nothing. The gaps began to fill in 2 years ago. First, astronomers using the Hubble Space Telescope discovered that the supermassive black holes were common in nearby galaxies too, and every galaxy could harbor one of the dark beasts (Science, 1 September 2000, p. 1484). Then, the ASCA x-ray satellite spotted an unusually bright x-ray source in the galaxy M82, thought to come from the superheated gas surrounding a black hole weighing about 100 solar masses. But was it a rarity?

    Ubiquitous.

    Chandra pinpointed several new medium-mass black holes in galaxy NGC 253.

    CREDIT: NASA/SAO/CXC

    Absolutely not, a chorus of speakers told those attending the meeting. Using images of 40 nearby galaxies taken with the Chandra X-ray Observatory, three teams have brought the count to almost 100. Astrophysicist Kim Weaver of Goddard Space Flight Center in Greenbelt, Maryland, who led one of the teams, argues that these black holes could spiral to the center of the galaxy and coalesce into a supermassive hole. “There is definitely enough material there to do this,” agrees Andrew Ptak, an astrophysicist at Carnegie Mellon University in Pittsburgh, who leads a second team.

    Not everyone is convinced that the middleweight holes can add up. “You need a lot of 100-solar-mass black holes to make a million-solar-mass black hole,” says Nick Scoville, an astronomer at the California Institute of Technology in Pasadena. But then, Chandra has only begun to hunt.

    Asteroids Stir Up Planets-to-Be

    Asteroids are probably kicking up a surprisingly small cloud of swirling dust observed around a nearby star, astronomers report. The protoplanetary disk is the first ever found that is small enough to congeal into a near twin of our solar system—and it may already harbor a Jupiter-sized planet.

    Astronomers, at least some of them, think they know how planets form: Chunks of rock orbiting a star in a protoplanetary disk collide and stick together, eventually clearing a path through the disk as most of the rocks in the orbit smack onto the growing planet. Clouds of dust billow out of these collisions and settle into a band of asteroids called a debris disk. In the past 2 decades, astronomers have detected infrared radiation from debris disks around several stars.

    Planet seeds

    Dust clouds near zeta Leporis (left) suggest that the star system harbors an asteroid belt like the one in our solar system (right).

    CREDIT: C. H. CHEN AND M. JURA

    All these disks are much larger than the solar system, ranging in size from 70 to 100 astronomical units. (1 AU equals the distance from Earth to the sun.) Dust gets hotter the closer it is to the star, and a 10-year-old series of observations suggested that the dust surrounding zeta Leporis—a younger and slightly heavier version of our sun 70 light-years away—was hot enough to harbor an exceptionally small disk.

    Now astronomers Christine Chen and Michael Jura of the University of California, Los Angeles, have snapped a precise photo of the disk. They find a thick disk of dust that extends to within 2.5 AU of zeta Leporis. “Dust usually spirals into a star within 20,000 years,” says Chen. And because the first dust clouds would have formed with the star nearly 100 million years ago, Chen and Jura argue that “this disk must be continually replenished by asteroid collisions.” They estimate that the zeta Leporis asteroid belt holds 200 times as much mass as the belt between Mars and Jupiter, enough to form a small planet.

    At least one planet might already be there. Asteroids start life on circular orbits that rarely collide. The pull of a Jupiter-sized planet could be the instigator that keeps the grinding, planet-forming bumper-car game around zeta Leporis running, says astronomer Mark Sykes of the Steward Observatory in Tucson, Arizona.

  15. ECOLOGY

    A New Wind Sweeps the Plains

    1. Paul Thacker*
    1. Paul Thacker is a science writer in Jersey City, New Jersey.

    Grasslands researchers have helped shape a controversial new plan that calls for reducing cattle grazing to benefit wildlife, but some ranchers say they will resist

    The early 1980s were a difficult time to be a researcher on South Dakota's Buffalo Gap National Grasslands, a windswept range where dozens of ranchers graze their cattle. Many of the ranchers were convinced that native prairie dogs were eating grass needed by their cows, and they weren't happy to learn that rodent eradication programs might be challenged. So when U.S. Forest Service biologist Dan Uresk began briefing ranchers on his studies showing that the prairie dogs don't compete with the cows for food—and might even increase the amount of available forage—“they didn't believe it,” he recalls. “Some would get mad and walk out,” while others left threatening phone messages.

    Next month, however, the Forest Service is expected to release a new grasslands management plan that draws heavily on what Uresk and other scientists have learned about these great plains. The plan, which covers 1.17 million hectares of public land in four states, calls for de- emphasizing traditional uses such as grazing in favor of wildlife such as the prairie dogs and judging managers' success by the health of the ecosystem instead of the size of the herds. “It's a major shift,” says Kirk Koepsell of the Grasslands Sierra Club, an environmental group in Sheridan, Wyoming. But some ranchers say the plan endangers their livelihood, and they're threatening to challenge the new rules in court.

    The new Northern Great Plains Management Plan—which took 5 years to write and drew over 110,000 comments—represents the latest chapter in 70 years of prairie controversy. In the 1930s, the federal government stitched together a set of public grasslands from failed Dust Bowl farms across Nebraska, Wyoming, and North and South Dakota, then rented grazing rights back to ranchers at deeply discounted rates. Today, ranchers often pay less than 15% of the price they would on private lands and also have a major voice in managing the public grasslands through local grazing associations.

    Over the last several decades, however, environmentalists and government biologists have complained that the arrangement has led to overgrazing and extensive damage to habitat needed by wildlife, such as beleaguered grassland birds. In the 1980s and 1990s, for instance, North Dakota officials commissioned studies that concluded that half of all federal grazing allotments in their state contained “poor” wildlife habitat, and that up to half of grassland riparian areas, or streamside corridors, were threatened by the trampling of cattle.

    In the wake of such research, Forest Service officials are about to unveil a new approach to overseeing the region's eight National Grasslands and two National Forests. In general, the decade-long blueprint calls on grassland managers to shoot for “desired conditions” that are friendlier to wildlife, such as a range of grass heights that will harbor more species, officials say. Another major goal is to boost populations of black-tailed prairie dogs, which are an important source of food for the black-footed ferret, a highly endangered species that federal biologists are trying to save.

    Although each grassland will have some flexibility, the plan is expected to reduce grazing in many areas. In North Dakota, for instance, ranchers could soon lose 10% or more of their grazing privileges. Even modest reductions should help restore the “better mosaic of low, mid, and high grasslands which birds and wildlife require,” says John Sidle, an endangered-species specialist with the Forest Service in Chadron, Nebraska. Eliminating grazing is not necessarily desirable, grasslands biologists note, because cattle have replaced the bison that once thundered across the plains, providing the disturbance required for some plants to prosper.

    But the anticipated cutbacks don't sit well with many ranchers, and the plan's bid to boost prairie dog numbers is fueling controversy. Until recently, many ranchers and government officials considered the small burrowing rodents, which can build teeming “towns,” to be a leading pest. They complained that prairie dog holes frequently injured livestock, and that the rodents competed with cattle for food. As a result, state and federal governments spent millions over the last century trying to exterminate them, helping drive their numbers to 1% of historic levels.

    In the last decade, however, environmentalists have persuaded officials to curtail eradication efforts on public lands, in part to aid ferret recovery. And 2 decades of research disprove the competition concept, says Uresk. His early studies, for instance, found that total plant production is 24% higher in areas inhabited by prairie dogs than in areas that are grazed. And plant biomass is 13% higher in areas that hold both cattle and prairie dogs, compared to areas that hold just cattle. Overall, Uresk says, newer studies confirm that prairie dogs and cows directly compete for less than 10% of available forage.

    Such data do little to mollify some ranchers. With help from skeptical members of Congress, they have already delayed the release of the plan once in a bid to soften some provisions. And some North Dakota ranchers now say they will work mightily to limit the plan's impact as it is phased in over the next few years—and perhaps even sue once it is formally adopted this summer.

    Forest Service officials, however, say the plan still gives grazers plenty of influence and note that the economic impact of any changes should be minimal, because less than one-tenth of 1% of the national cattle herd grazes on federal land. Their goal, they say, is not to force modern cowboys from the grasslands but to rein in grazing to reduce negative side effects. “Grazing is an important [land management] tool; I just wish we were in more control of it,” says Sidle. The plan will just try to put the cows in the right places at the right times.

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