News this Week

Science  28 Nov 2003:
Vol. 302, Issue 5650, pp. 1484

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    One-Two Punch Leaves Physicists Gasping for Breath

    1. John Bohannon,
    2. Barbara Casassus*
    1. John Bohannon writes from Oxford, U.K. Barbara Casassus writes from Paris.

    PARIS—Scientists in France are reeling from the news that one of the country's largest research institutions, the Commission for Atomic Energy (CEA), intends to pull out of two major physics facilities: the Soleil synchrotron now under construction and the venerable Orphée neutron reactor. The pending cuts are the result of severe belt-tightening at CEA, which also plans to trim its scientific staff over the next several years.

    CEA's woes began earlier this year, when the government announced that it would cut research funding across the board by more than 9% in 2003. Alain Bugat, who was appointed CEA director last January, says that the previous CEA management had failed to come to terms with the commission's financial predicament: It had long been clear, he claims, that there were insufficient resources to cover CEA's ambitious slate of research programs. They were “dreaming,” Bugat says. So over the past few months, he drafted a financial plan through 2012, details of which were first reported last week in the newspaper Libération.

    The plan calls for cutting €1.4 billion from CEA's €18.3 billion civil budget for the 2004 to 2012 period. One high-profile casualty is the Soleil synchrotron, a third-generation machine that is intended to serve everyone from structural biologists to materials scientists. Bugat says that CEA will not pay its 10% share of operating costs of the €385 million facility, due to come on line for some experiments as early as 2006. That will force Soleil managers to find other sponsors to plug the gap. It will also cut CEA researchers out of the action at Soleil, just 1 kilometer down the road from CEA's main research labs in Saclay. “It doesn't make sense for the CEA to pay for the construction of Soleil and then not to use it,” says François Gounand, director of materials sciences at CEA.

    Le misérable?

    Neutron research director Pierre Monceau says that “some research may have to simply stop” in the wake of proposed cuts at France's Commission for Atomic Energy. The Soleil synchrotron (bottom) is among the casualties.


    Another victim is the Orphée neutron reactor, also in Saclay. CEA plans to zero out the $7 million a year it spends on the 21-year-old facility, which is used by physicists, nuclear chemists, and some biologists. Orphée will be closed in 2006 unless a new source of financing is found, says Bugat. CEA also plans to eliminate 40 positions and freeze hiring in nuclear and particle physics and astrophysics over the next 2 years. They had to “show courage and make choices,” says Bugat, who views the downsizing of the 600-strong scientific staff in the physics department as the “touchiest issue.”

    Scientists are stunned. The proposed cuts are more drastic than expected, says Pierre Monceau, director of the CEA-funded Léon Brillouin neutron research facility in Saclay. “Some research may have to simply stop,” he says. Others view the plan as CEA lurching toward applied projects. Bugat and other CEA managers “do not appreciate basic research,” contends Alain Milsztajn, a CEA nuclear physicist in Saclay. The job losses, adds CEA neutrino physicist Michel Cribier, take aim at a research community that's already suffering: “Particle physics has already lost 25% of its researchers [in France] in 6 years.”

    Three of four ministries that must approve the plan have done so, government sources say. The lone holdout is the research ministry. With the fate of CEA research still hanging in the balance, Milsztajn and other CEA physicists have banded together as the Committee for the Defense of Basic Research to negotiate with Bugat and the government.

    Bugat is likely to take a hard line. For the last 25 years, he says, CEA should have been working to reduce redundancies in physics research between itself and the French basic research agency CNRS. He points out that France is already under fire from the European Commission for failing to keep public spending to defined limits. Although the cuts will delay some projects, Bugat insists that this will not damage CEA's research enterprise and says that basic research will hold steady at 35% of the commission's civil budget. “A year here and there on long-term projects will make no difference,” he says.

    Others are not so sure. Besides harming CEA research, the cuts could imperil France's contributions to international projects such as a German-French effort to develop high-temperature superconductors, argues Monceau: “We could lose our place in these collaborations.” As bad as it looks for French physicists, it may yet get worse.


    For Spain, Oil Spill Disaster Is in the Bag

    1. Xavier Bosch*
    1. Xavier Bosch is a science writer based in Barcelona.

    BARCELONA—The Spanish government has given a green light to a pioneering attempt to salvage the remaining oil from the wreck of the Prestige. The €100 million operation in deep waters off the Galician coast will deploy an ingeniously simple technique: It will decant the oil from the tanker's holds into giant bags and haul them to the surface. After months of rancor, Spanish scientists are rallying behind the plan.

    During a heavy storm on 19 November 2002, the Prestige split in two and sank roughly 200 kilometers off Galicia. At least 79,000 metric tons of oil ended up coating shellfish beds and polluting 900 kilometers of French and Spanish coast, inflicting about $1 billion worth of damage (Science, 29 November 2002, p. 1695). A letter signed by more than 400 scientists and published in Science blasted the Spanish government for largely ignoring scientific advice after the accident (24 January, p. 511). Relations improved, however, and in February a scientific panel advised the government to extract or entomb the estimated 38,000 tons of oil left in the wreck. The government opted for removal and tapped the Madrid-based oil giant Repsol to undertake the unprecedented operation.

    A simple plan.

    Bagging Prestige oil worked like a charm in recent field trials.


    Repsol had to come to grips with a “major technological challenge,” says the company's technical director, Ramón Hernán. The Prestige lies almost 4000 meters below the surface, and no oil had ever been salvaged at such great depth. With help from researchers at the University of Huelva and several foreign firms, Repsol adapted four remotely operated submersibles for the job. In field trials last month, the subs sealed some of the wreck's gaping holes, decreasing the amount of escaping oil from 700 liters to just 10 liters per day. The team also estimated that 13,700 tons of oil were left in the wreck, much less than previously thought.

    To get that oil out, Repsol engineers turned to giant plastic bags. On 16 October, the team used a submersible to hook a 250-ton bag to the Prestige's bow before drilling a hole into one of the smaller holds. Over 18 hours, 100 tons of fuel flowed upward into the bag “without spillage into the sea,” says Hernán. The bag was sealed and hauled to the surface by submersible. Further tests earlier this month also proved successful.

    The technology “sounds promising,” says marine biologist Richard Steiner of the University of Alaska, Fairbanks, who helped assess how the Exxon Valdez oil spill in 1989 harmed wildlife in Alaska's Prince William Sound. Pablo Serret, a biological oceanographer at the University of Vigo and an instigator of the letter published in Science, welcomes the salvage operation, which is expected to begin in the spring and last for 3 months.


    Cambridge Center Wins a Round

    1. Richard Stone

    CAMBRIDGE, U.K.—The University of Cambridge (UC) has won a major victory in its 5-year quest to build a $50 million primate research facility. On 21 November, U.K. Deputy Prime Minister John Prescott approved UC's proposal to site a world-class Centre for Behavioural Neuroscience in Cambridge. But UC officials are keeping the champagne corked: They admit they may not be able to raise enough money to cover the controversial center's escalating costs.

    UC officials want a center that would bring all the university's primate research under one roof and allow it to expand work on potential treatments for everything from schizophrenia to Alzheimer's disease. Local authorities had twice refused to grant planning approval on the grounds that protesters might snarl traffic and perhaps harm staff or themselves. After a hearing late last year, a special inspector recommended that UC's second appeal be dismissed. Prescott, in a 28-page decision, trumped the inspector and granted permission, concluding that “it is strongly in the national interest that a development of this kind should proceed promptly in the Cambridge area, close to the university and its concentration of research personnel.”

    The decision appears to be a deathblow to an alternative proposal to site the center at a tightly guarded military outfit, such as the Defence Science and Technology Laboratory's Porton Down facility (Science, 14 November, p. 1127). UC Pro-Vice-Chancellor Anthony Minson says that UC officials have no inclination to see it built there. “It's not the kind of science that is easily divorced in space and time from an academic setting,” he says. Colin Blakemore, chief executive of the U.K.'s Medical Research Council, agrees. “I oppose it being sited at Porton Down,” he told Science. A Home Office official says, however, that the government could still insist that UC “explore that alternative more fully.”

    In the end, though, Cambridge's victory may be pyrrhic. The cash-strapped university says it now can't meet the center's costs, which have risen 33% since UC first aired the proposal. “It's on hold until we can sort the finances out,” says Minson. The “major concern,” he says, is the running cost, pegged for now at roughly $2.5 million a year. But Minson insists that UC remains committed to the project. “We're not looking to have a victory and then withdraw,” Minson says. “We want to do the science.”


    Nobelists Go Four-on-One With Cheney

    1. Jocelyn Kaiser

    Could 2 hours of face time with Vice President Dick Cheney and other senior White House operatives be worth a few billion dollars for science funding? That's what four Nobel Prize winners were hoping last week after an unusual morning of one-on-one meetings with top Bush Administration officials.

    Biologists Sidney Altman, Thomas Cech, and Alfred Gilman and atmospheric chemist F. Sherwood Rowland spent 40 minutes with Cheney and 45 minutes with budget czar Josh Bolten, and they held discussions with science adviser John Marburger and aides at the White House Office of Science and Technology Policy. Cheney “mostly listened,” Gilman said later, whereas Bolten “asked many good questions” about the science budget.

    The Nobelists stressed the need to avoid losing momentum at the National Institutes of Health (NIH), which just completed a 5-year doubling and now faces much smaller increases. They also emphasized the need to maintain support for physical sciences and for other agencies. Discussions touched on visa restrictions, the funding difficulties of young investigators, and the drug industry's reliance on NIH research.

    Bolten asked one tough question: If the total budget for science were fixed, what other agency would Nobelists cut to sustain NIH? “We unanimously rejected the premise,” said Rowland.

    The Nobelists admitted that it was impossible to measure the impact of their visit. “What's most important is that [we] sat down and talked face-to-face [with the Administration],” says Robert Wells, president of the Federation of American Societies for Experimental Biology, which organized the visit.


    Military Wins Changes That May Ease Research

    1. Jocelyn Kaiser

    Environmentalists were dismayed last week when Congress exempted the Department of Defense (DOD) from environmental rules protecting endangered species and marine mammals. But the new language, part of a bill reauthorizing all DOD programs, appears to contain a silver lining for some researchers: It removes red tape from scientific studies of marine mammals that do essentially no harm. The law's murky wording, however, leaves it unclear whether the provision applies only to research done directly for a federal agency.

    The Pentagon says that the changes are needed to improve defense readiness. For example, the bill would allow the Navy to request an exemption from the Marine Mammal Protection Act (MMPA) for using sonar to detect submarines. DOD also argued successfully that it should not have to designate critical habit for endangered species on lands, such as military bases, that already had a management plan.

    Despite protests from environmental groups, which regard the changes as unnecessary and damaging, the only Pentagon requests that Congress rejected were exemptions from some pollution laws. Already, the Navy has said it may use the legislation to renegotiate a court settlement reached this fall that limits its use of a controversial sonar system (Science, 5 September, p. 1305).

    Making waves.

    Congress has eased the rules governing activities that affect whales and other marine mammals.


    Although scientists are also troubled by several revisions, some marine mammal researchers agree with DOD on one point: MMPA's definition of “harassment” of an animal is too broad (Science, 6 June, p. 1486). For example, researchers conceivably could need a permit for a study that causes an animal to simply turn its head, notes anatomist Darlene Ketten of the Woods Hole Oceanographic Institution in Massachusetts. The DOD bill raises the bar by defining harassment as an act that has “significant potential” to injure an animal or one that causes “abandoned or significantly altered” behavior.

    Exactly who is covered by the looser definition remains unclear, however. The bill, which President George W. Bush was expected to sign into law this week, says it applies to military activity “or a scientific research activity [on marine mammals] conducted by or on behalf of the Federal Government.” But whether that encompasses any scientist with federal funding is up to “agencies and lawyers” to decide, says Karen Steuer, a former House staffer who now advises the National Environmental Trust in Washington, D.C. In any case, she notes, not all marine mammal researchers receive federal funding. Nor does the law ease the rules for scientists doing ocean research that affects mammals incidentally, says Penelope Dalton of the Consortium for Oceanographic Research and Education in Washington, D.C.

    Some critics also point to ambiguous language in a report accompanying the bill. For example, although the report discusses “biologically significant” impacts, a term scientists have pushed for, it defines altered behavior as a “long-term” change in a “species or stock,” which could be impossible to determine, Steuer says. The report and the final bill are “inconsistent,” agrees Donna Wieting of the National Marine Fisheries Service, which must craft regulations to enforce the act.

    Observers are hoping that the changes will be revisited next year, when Congress resumes work on updating MMPA. Those changes “are going to be very important” to scientists, Ketten says.


    Triple-Threat Microbe Gained Powers From Another Bug

    1. Dan Ferber

    The long-dreaded superbug surfaced on a summer Friday in 2002. The new strain of Staphylococcus aureus, cultured from foot ulcers on a diabetes patient in a Detroit dialysis center, had developed resistance to vancomycin, one of the few antibiotics left that reliably kills staph. Doctors rushed the strain to the Centers for Disease Control and Prevention in Atlanta, and nine local and CDC public health officials scoured the dialysis center and tested more than 300 people the patient had come in contact with, collecting samples to see if it had spread. It hadn't. “We dodged another bullet,” says clinical microbiologist Donald Low of the University of Toronto.

    Now a study on page 1569 shows how the microbe became a menace. Microbiologists Linda Weigel and Fred Tenover of CDC and colleagues found that the bug likely acquired the vancomycin-resistance trait from another microbe common in hospital settings, a dangerous alliance that health officials had long feared. The new S. aureus strain also resisted most common antibiotics, including penicillin, methicillin, and ciprofloxacin, and it possessed the genetic machinery to pass drug resistance on to drug-susceptible S. aureus strains.

    S. aureus commonly lives on the skin and in the noses of healthy people, causing nothing worse than pimples and boils. But in hospitalized patients, it causes tens of thousands of infections each year, including serious and sometimes fatal surgical-wound infections, bloodstream infections, and pneumonia. Penicillin saved many patients, but the microbe soon learned to evade it, and over the past half-century it has developed resistance to one antibiotic after another.

    By the late 1980s, vancomycin was the “drug of last resort” for multidrug-resistant strains, Tenover says. In 1992 researchers showed that a vancomycin-resistant strain of Enterococcus faecalis, which also infects hospitalized patients, could transfer its resistance genes to S. aureus on the skin of a mouse. “We began to anticipate that at some point we'd see high-level resistance moving into S. aureus,” Tenover says.

    Dangerous liaison.

    Vancomycin resistance probably jumped from E. faecalis to S. aureus via a plasmid (black loop) carrying a transposon (red) that then infested the resident plasmid (blue).


    When the Detroit vancomycin-resistant S. aureus (VRSA) strain appeared, the detective work began. Doctors isolated two strains from the patient. One resisted almost all available antibiotics. The other, from the woman's foot ulcer, resisted the same drugs plus vancomycin. Doctors also cultured vancomycin-resistant E. faecalis from her foot ulcers.

    The two S. aureus strains were otherwise identical to each other and similar to a menacing S. aureus strain that commonly infects hospital patients. Circular loops of DNA called plasmids from the VRSA and E. faecalis strains, but not the susceptible S. aureus strain, had a gene called vanA that wards off vancomycin. That suggested that the drug-resistance gene had jumped species, Weigel says.

    To see how it made the jump, the researchers checked the plasmids for a mobile genetic element called a transposon, a snippet of DNA that can jump out of one plasmid and worm its way into another. As has been found in other vancomycin-resistant E. faecalis strains, this one hosted a plasmid with a transposon containing vanA. The transposon appeared in a plasmid in the new VRSA strain as well. Colleagues at The Institute for Genomic Research in Rockville, Maryland, sequenced the entire VRSA plasmid, showing that the transposon was intact and ready to jump.

    Together, the results suggest that E. faecalis in the woman's ulcer sidled up to S. aureus and passed along its resistance plasmid. Enzymes in S. aureus seem to have destroyed the foreign E. faecalis plasmid, but before that happened, the transposon jumped, like a rat escaping a sinking ship, and infiltrated the S. aureus's resident plasmid to create a new hybrid. That created a nasty new S. aureus strain that can spread readily in hospitals, resist almost all the drugs available to kill it, and share its weapons with S. aureus cousins that remain vulnerable to vancomycin. “What we've isolated is really the triple threat,” Tenover says.

    In the clinic, says Low, “it's critical for laboratories to be on the lookout” for new VRSA strains and for doctors to work to keep them in check. Two antibiotics, linezolid (Zyvox) and quinupristin/dalfopristin (Synercid), still stop VRSA, but it's important that drug companies step up efforts to develop alternatives, he says: “Right now we've got something in our back pocket, but that could change rapidly.”


    Inverse Doppler Demonstration Ends a 60-Year Quest

    1. Robert F. Service

    You're daydreaming at a railroad crossing while a train whistles past. As the engine passes, you expect to hear the pitch drop as the Doppler effect dictates. Instead, it rises. Your eyes widen. What gives?

    Ask Nigel Seddon and Trevor Bearpark, physicists with the R&D arm of BAE Systems, a defense contracting firm in Bristol, U.K. On page 1537, they describe an electronic setup that generated an inverse Doppler effect, something theorists have pondered since 1943. “We were absolutely flabbergasted,” Seddon says of the day the readings came across the oscilloscope. “For a good hour we just played with the experiment.”

    “It's great work,” says Nader Engheta, a professor of electrical and systems engineering at the University of Pennsylvania in Philadelphia. Seddon and Bearpark suggest that the effect could spawn the development of cheap, compact devices that turn out a broad range of gigahertz-frequency electromagnetic pulses. Researchers around the globe are investigating gigahertz systems for nondestructive testing of materials, among other uses. But traditional gigahertz generators are bulky and expensive and produce a narrow range of frequencies.

    The standard Doppler effect occurs when sound or other waves come from or bounce off a moving object. If that object is approaching, the waves are essentially pushed closer together, so their frequency rises. If the object is receding, the waves spread out, and the frequency drops.

    To make that happen in reverse, the U.K. researchers needed to clear two big hurdles. First, they had to put a material into a state called anomalous dispersion that could support the specialized waves needed to produce an inverse Doppler effect. Then they had to generate a moving barrier within that material to reflect waves.

    Such a feat is possible because waves have two moving components. One is the energy of the overall pulse of waves. The second is a property known as the phase, which is the relative position of a single point—such as the crest of one wave—within the bunch. In familiar materials, such as copper wire, the overall energy in the wave and the phase move in the same direction. But in materials with anomalous dispersion, the energy moves forward but the phase moves in reverse (see figure).

    Strange change.

    In anomalous dispersion (bottom), waves move against the flow of energy, creating an inverse Doppler effect.


    Adapting an approach sketched out 3 years ago by Russian theoretical physicists Avenir Belyantsev and Alexander Kozyrev, Seddon and Bearpark created a lab-scale transmission line with anomalous dispersion by linking a series of electronic devices called capacitors and inductors. They then sent a large pulse of current into their device-based transmission line. As the pulse moved, it altered the magnetic structure of the line, creating a nonmagnetic region in its wake. That produced a moving barrier between the magnetic and nonmagnetic regions of the transmission line. At the same time, the pulse acted like a shock wave that generated a radio frequency (RF) wave. The RF wave traveled backward toward the start of the transmission line, reflected off the front of the apparatus, and then moved back up the line toward the original pulse.

    Traveling faster than the original electromagnetic pulse, the RF wave caught up with the receding barrier and bounced off it. Because it was moving through a material with anomalous dispersion, the phase of the RF wave was traveling in the opposite direction from its energy. As a result, when the wave hit the receding barrier, it reflected not with a lower frequency as usual but with a higher frequency. And physicists everywhere got a pleasant jolt of surprise.


    Early Date for the Birth of Indo-European Languages

    1. Michael Balter

    Ever since British jurist Sir William Jones noted in 1786 that there are marked similarities between diverse languages such as Greek, Sanskrit, and Celtic, linguists have assumed that most of the languages of Europe and the Indian subcontinent derive from a single ancient tongue. But researchers have fiercely debated just when and where this mother tongue was first spoken.

    Now a bold new study asserts that the common root of the 144 so-called Indo-European languages, which also include English and all the Germanic, Slavic, and Romance languages, is very ancient indeed. In this week's issue of Nature, evolutionary biologist Russell Gray and his graduate student Quentin Atkinson of the University of Auckland in New Zealand combine state-of-the-art computational methods from evolutionary biology with an older technique for dating languages, called glottochronology. Their results suggest that a proto-Indo-European tongue was spoken more than 8000 years ago by Neolithic farmers in Anatolia, in central Turkey; these farmers then spread it far and wide as they migrated from their homeland.

    “It is almost too good to be true,” says Margalit Finkelberg, a classicist at Tel Aviv University in Israel who has long favored this so-called Anatolian hypothesis. But many linguists prefer a competing theory, which traces Indo-European languages to Kurgan horsemen in southern Russia about 6000 years ago. Some of these researchers challenge the new methodology as well as its conclusions. “I cannot possibly accept [their] results,” says linguist Craig Melchert of the University of North Carolina, Chapel Hill, who adds that the paper “simply reconfirms the unreliability of any glottochronological model, no matter what improvements are made.”

    First words.

    A new study suggests that Indo-European languages arose 8700 years ago. Dotted lines indicate uncertainties.


    Glottochronology uses the percentage of “cognates”—words with shared roots—to determine how long ago different languages diverged. For example, the Sanskrit and Latin words for “fire,” agnis and ignis, show clear evidence of a common origin. But the technique has long been out of favor, in part because of its flawed assumption that words change form steadily over time. Gray and Atkinson revived the method with powerful statistical techniques now used by biologists to determine the evolutionary trees of living organisms, such as Bayesian inference, maximum likelihood analysis, and a trick called “rate smoothing” that allows the rate of word change to vary (Science, 14 December 2001, p. 2310). The team members applied their method to a database previously compiled by Yale University linguist Isidore Dyen, comprising 2449 cognate sets from 87 Indo-European languages. They added Hittite, an extinct Anatolian language, and Tocharian A and B, once spoken in western China.

    No matter how they varied parameters such as the rate of word change or the length of branches on parts of the tree, the answer came out pretty much the same: Indo-European languages initially diverged between 7800 and 9800 years ago, with the best guess being around 8700 years. “Try as we might, we just couldn't get [younger] dates,” says Gray. Moreover, the analysis showed ancient Hittite to be closest to the root of the language tree, providing a slam dunk for the Anatolian hypothesis.

    “The conclusions coincide in all essentials with those at which the adherents of the Anatolian theory … have arrived on independent grounds,” says Finkelberg. Others praise the ambitious new technique. “Computational methodologies of this kind can only be helpful for historical linguistics,” says linguist April McMahon of the University of Sheffield, U.K.

    Yet some researchers question the basic assumptions of the study. “The characteristics of languages and biomolecular sequences evolve in very different ways,” says Tandy Warnow, a computer scientist at the University of Texas, Austin. Gray and Atkinson “used techniques that are not appropriate for their data.” Linguist Don Ringe of the University of Pennsylvania in Philadelphia notes that the study relied entirely on the Dyen database, which tracks word changes but not grammar or construction changes. “[This is] the least reliable type of data” for building language trees, Ringe says.

    As arguments over both method and results continue, Gray and Atkinson raise a possible compromise solution regarding the timing. They identified a rapid divergence about 6500 years ago that gave rise to the Romance, Celtic, and Balto-Slavic language families—very close to the time of the postulated Kurgan expansion. The Kurgan and Anatolian hypotheses, they write, “need not be mutually exclusive.”


    Polar Storms Reboot the Sun's Magnetic Program

    1. Robert Irion

    Our sun is a magnetic mess. Churning loops of charged gas continually roil its surface and atmosphere, especially when the sun nears the end of its 11-year cycle of flipping its magnetic field. Now, solar physicists have identified the key process that clears the way for freshly realigned magnetic fields to take root at the sun's poles: the titanic eruptions of gas called coronal mass ejections (CMEs).

    A new study of thousands of CMEs reveals that the eruptions sweep away the stubborn remnants of old magnetic field at each pole. These high-latitude CMEs have no direct connection to the well-studied sunspots near the sun's equator, but they now appear more critical to understanding the sun's overall magnetic rhythms. “This is the first clear evidence that CMEs are related to the sun's polarity reversal,” says solar theorist Boon Chye Low of the National Center for Atmospheric Research in Boulder, Colorado. “It's a very strong case.”

    The evidence comes from analysis of images taken by the Solar and Heliospheric Observatory (SOHO), which stares at the sun from a perch 1.5 million kilometers from Earth. A team led by solar physicist Nat Gopalswamy of NASA's Goddard Space Flight Center studied nearly 7000 CMEs caught by SOHO between 1996 and 2002. Most eruptions spewed from low and mid- latitudes, where sunspots mark the emergence of tangled magnetic fields. These active regions get most of the attention from scientists, because they can launch hazardous storms toward Earth.

    Thrown for a loop.

    A coronal mass ejection (bottom) severs the base of a magnetic arch and blasts the loop into space.


    In the 20 November Astrophysical Journal Letters, Gopalswamy's team focused on the 1200 CMEs that shot into space from latitudes greater than 60 degrees. Comparing the timing of the eruptions with ground-based records of magnetic field patterns at the poles, the researchers found a striking correlation. The polar eruptions climaxed for about 18 months as the field directions flip-flopped in chaotic fits and starts. But as soon as the new magnetic field was in place, the CMEs stopped. A similar pattern was evident in CMEs observed by a U.S. Air Force satellite from 1979 through 1985.

    The team believes that each CME severs the bases of magnetic structures called polar crown filaments. A steady near-surface flow of electrically charged gas away from the equator pushes the magnetic field relentlessly toward the poles. Near the end of the 11-year cycle, the filaments crowd together like thickets of McDonald's golden arches, poking above the sun's surface into its atmosphere, or corona. Anchored to the sun, they form the last stand of the old magnetic alignment, until energetic CMEs rip them from the sun and expel billions of tons of charged gas from the corona. “CMEs remove the polar crown filaments,” Gopalswamy says. “They stretch and change the magnetic field conformation in such a way that the polarity ultimately changes.”

    Low thinks the study will compel solar physicists to look at CMEs in a new light. “The focus has always been on individual eruptions,” he notes. “This paper represents one of the first attempts to look at the collective effects of CMEs. They have a major global influence.”


    Sweeping Up After the Solar System

    1. Richard A. Kerr

    By all rights, the outermost solar system shouldn't be so far from its home star. At 30 times Earth's distance from the sun, Neptune should never have come together from the thin gruel of icy debris that lingered that far out at the solar system's birth (Science, 10 December 1999, p. 2054). Even the thinly populated disk of small, icy bodies beyond Neptune called the Kuiper belt shouldn't have formed there given the meager mass it appears to have had to work with. Now, two solar system dynamicists, building on earlier work, have come up with an explanation: They suggest that nothing in the outermost solar system—not Neptune, Pluto, or any part of the Kuiper belt—formed where we see it today.

    Drawing on new computer simulations of the early solar system, solar system dynamicists Harold Levison of the Southwest Research Institute in Boulder, Colorado, and Alessandro Morbidelli of the Observatory of the Côte d'Azur in Nice, France, conclude that when Neptune migrated outward, it brought the entire contents of the Kuiper belt with it. “We're the first to suggest that all the [Kuiper belt] objects were pushed out” there, says Levison. The results are being published this week in Nature.

    Dynamicists have been arguing for years now that various bodies must have moved into the outermost solar system. For 20 years they've realized that gravitational interactions between Neptune and the surrounding dense disk of gas, dust, and small protoplanets would have driven the planet outward in the late stages of solar system formation to its present position. In 1995, solar system dynamicist Renu Malhotra of the University of Arizona in Tucson showed that a migrating Neptune would in turn have pushed Pluto ahead of it. Large bodies can push small ones around when the smaller one is in a resonant orbit: an orbit that allows the larger body to nudge the smaller one repeatedly at the same point in its orbit, the way repeated pushes of a swing at the same point in its motion send it higher.

    Solar system bully.

    Neptune (backlit by sun) may have pushed Kuiper belt objects into place.


    And this year in Icarus, dynamicist Rodney Gomes of the National Observatory in Rio de Janeiro showed how Neptune could have gravitationally hurled some small objects out into the present Kuiper belt at 40 to 50 times Earth's orbital distance. There, neptunian resonances could have trapped and released a few of them, accounting for the Kuiper belt objects (KBOs) that have wildly elongated and tilted orbits.

    That still left a big puzzle: the numerous KBOs whose orderly orbits suggested that they had formed in place. Dynamicists calculate that for bodies of any size to form, there would have to have been 100 times the present mass there. Where did all the missing mass go? Levison and Morbidelli have sidestepped that seemingly intractable problem by showing that—contrary to standard theory—Neptune could have pushed some bodies into the Kuiper belt without greatly distorting the shapes of their orbits.

    In a series of computer simulations, Levison and Morbidelli found that with enough total mass in the migrating neptunian resonance, more resonances appear, causing the trapped bodies' orbital shapes to vary between nearly circular and highly elongated. That means some would always be nearly circular. Close encounters of Neptune with passing protoplanets would have jiggled the planet as well as its resonance, shaking out these orderly bodies across the Kuiper belt as the resonance swept across it. Then it's no coincidence, the authors argue, that the resonance today coincides with the outer edge of the Kuiper belt, the rim of the solar system (Science, 27 October 2000, p. 689).

    The new variation on a Neptune push seems to work. “I think they've put their finger on an important part of the dynamics that was missing,” says Malhotra. The case could be strengthened when modelers get some more computing power to simulate all the transport mechanisms in one run. Or it could be weakened if astronomers find many KBOs beyond the presumed edge of the solar system.


    Anthrax Powder: State of the Art?

    1. Gary Matsumoto*
    1. Gary Matsumoto, an investigative journalist in New York City, is writing a book on biodefense.

    Although the investigation seems focused on the idea that the Senate powder could have been “homemade,” some experts say that's improbable

    When the anthrax mailers penned the message, “YOU CAN NOT STOP US. WE HAVE THIS ANTHRAX,” the threat included a chilling nuance that remains largely unrecognized. “ARE YOU AFRAID?” asked the attackers. “Yes,” should have been the answer, according to some biodefense experts, who think that the anthrax spores mailed to Senators Thomas Daschle (D-SD) and Patrick Leahy (D-VT) in the fall of 2001 represented the state of the art in bioweapons refinement, revealing telltale clues about the source. This view is controversial, however, because others dispute the sophistication of the Senate powder, and a schism now exists among scientists who analyzed it for the FBI.

    One group, comprised mostly of microbiologists and molecular biologists, argues that this material could have been a do-it-yourself job, made by someone knowledgeable but with run-of-the-mill lab equipment on a modest budget. This contingent includes one well-known bioweaponeer, Ken Alibek, who defected from Russia to the United States in 1992.

    The other faction thinks that the powder mailed to the Senate (widely reported to be more refined than the one mailed to the TV networks in New York) was a diabolical advance in biological weapons technology. This diverse group includes scientists who specialize in biodefense for the Pentagon and other federal agencies, private-sector scientists who make small particles for use in pharmaceutical powders, and an electronics researcher, chemist Stuart Jacobsen of Texas.

    Rapid release.

    The powder in letters sent to the U.S. Senate was treated in a sophisticated way to create an aerosol, some researchers say.


    Early in the investigation, the FBI appeared to endorse the latter view: that only a sophisticated lab could have produced the material used in the Senate attack. This was the consensus among biodefense specialists working for the government and the military. In May 2002, 16 of these scientists and physicians published a paper in the Journal of the American Medical Association, describing the Senate anthrax powder as “weapons-grade” and exceptional: “high spore concentration, uniform particle size, low electrostatic charge, treated to reduce clumping” (JAMA, 1 May 2002, p. 2237). Donald A. Henderson, former assistant secretary for the Office of Public Health Preparedness at the Department of Health and Human Services, expressed an almost grudging respect: “It just didn't have to be that good” to be lethal, he told Science.

    As the investigation dragged on, however, its focus shifted. In a key disclosure, U.S. Attorney General John Ashcroft revealed in August 2002 that Justice Department officials had fixed on one of 30 so-called “persons of interest”: Steven J. Hatfill, a doctor and virologist who in 1997 conducted research with the Ebola virus at the U.S. Army Medical Research Institute of Infectious Diseases in Fort Detrick, Maryland. (Hatfill has denied any involvement in the anthrax mailing.) Although the FBI did not spell out its theory, this announcement and leaks to the media from federal investigators indicated that the inquiry had embraced the idea that a lone operator or small group with limited resources could have produced the Senate anthrax powder.

    This premise now appears to have run its course. In September 2003, the FBI's Michael Mason admitted that the bureau failed to reverse engineer a world-class anthrax powder like the Senate material and expressed regret that Hatfill had been called a “person of interest.” One of the costliest manhunts ever conducted by federal investigators appears to be stymied. The FBI cannot or will not say whether the anthrax powder was foreign or domestic, expensively made or cheaply done, a professional job or the handiwork of an amateur.

    But the scientific data amassed so far should provide a wealth of information on the weapon's possible origins, say scientists in the group with expertise in such powders. They argue that the most striking qualities of the Senate powder do not concern the anthrax spores but the way they were processed—specifically, how they were given an electrostatic charge and unusual surface properties.

    If the Senate anthrax powder did in fact have these refinements, its manufacture required a unique combination of factors: a strain that originated in the United States, arcane knowledge, and specialized facilities for production and containment. And this raises the discomforting possibility that the powder was made in America, perhaps with the resources of the U.S. government.

    Charged questions

    There is no debating that the Senate powder was exceptionally pure and highly concentrated. Nor is there any doubt that it contained the Ames strain, one of the most virulent strains discovered. But what made it truly remarkable, according to biodefense specialists, was its conversion into a cutting-edge aerosol.

    That transformation had as much to do with chemistry and physics as with microbiology. Anthrax spores cling to one another if they get too close; sticky chains of proteins and sugar molecules on their surfaces latch onto each other, drawn by van der Waals forces that operate at a distance of a few tens of angstroms. Untreated spores clump into larger particles that are too heavy to stay airborne or reach the narrowest passages in the lung.

    To thwart this clumping, an earlier generation of biological weapons makers—operating out of Fort Detrick when it still made weapons—experimented with ways to prevent the surfaces of germs from getting too close. For example, William C. Patrick III, former chief of Fort Detrick's Product Development Division, pioneered the use of a dusty silica powder with nanometer-sized particles added to nonlethal incapacitating agents such as Francisella tularensis, the cause of tularemia (but not Bacillus anthracis, the cause of anthrax). “Otherwise,” says Patrick, the powder was “very hard to disseminate.”


    U.S. and Soviet bioweapons specialists discovered that adding silica particles to germ powders made them easier to disperse.


    In a separate research arena, pharmaceutical scientists in the 1990s began experimenting with adding electrostatic charges to small particles in medicinal powders designed for inhalation. Adding a like charge of sufficient strength creates an electrostatic field of up to a few centimeters, which makes particles repel one another, creating an “energetic” or self-dispersing powder.

    Biodefense scientists say they became aware that such an innovation could be applied to germ-warfare powders with deadly effect, especially deadly because charged particles are more prone to lodge in the lung. Once in the lung, immune cells transport the spores to lymph nodes, where the spores germinate and cause infection. The Senate anthrax spores carried like electrical charges, and some experts believe that they were added deliberately to aid dispersal.

    Was it a coincidence that this lethal innovation appeared in the anthrax spores sent to the Senate? Alibek thinks it is possible. The Senate anthrax could have acquired a charge from friction as the envelopes passed through mail-sorting machines. (Alibek also has speculated that the powders mailed to the Senate were more refined than those sent to the New York media and may have come from a different production run.) But his theory raises a question: Why would only the Senate powder acquire a charge from the sorting machines?

    Jacobsen, a research chemist who coated sub-5-micrometer particles with silica while working on a program for the Defense Advanced Research Projects Agency (DARPA), is skeptical of this idea. Jacobsen says that friction would add static electricity only to surfaces: “If anything, the sorting machine's pinch rollers and the envelopes should get charged,” he says, “not the spores inside.”


    Fort Detrick stopped making bioweapons in this defunct (and now demolished) lab more than 3 decades ago


    Glassy finish

    More revealing than the electrostatic charge, some experts say, was a technique used to anchor silica nanoparticles to the surface of spores. About a year and a half ago, a laboratory analyzing the Senate anthrax spores for the FBI reported the discovery of what appeared to be a chemical additive that improved the bond between the silica and the spores. U.S. intelligence officers informed foreign biodefense officials that this additive was “polymerized glass.” The officials who received this briefing—biowarfare specialists who work for the governments of two NATO countries—said they had never heard of polymerized glass before. This was not surprising. “Coupling agents” such as polymerized glass are not part of the usual tool kit of scientists and engineers making powders designed for human inhalation. Also known as “sol gel” or “spin-on-glass,” polymerized glass is “a silane or siloxane compound that's been dissolved in an alcohol-based solvent like ethanol,” says Jacobsen. It leaves a thin glassy coating that helps bind the silica to particle surfaces.

    Silica has been a staple in professionally engineered germ warfare powders for decades. (The Soviet Union added to its powders resin and a silica dust called Aerosil—a formulation requiring high heat to create nanoparticles, says Alibek. U.S. labs have tested an Aerosil variant called Cab-O-Sil, and declassified U.S. intelligence reports state that Iraq's chemical and biological warfare labs imported tons of both Cab-O-Sil and Aerosil, also known as “solid smoke,” in the 1980s).

    “If there's polymerized glass [in the Senate samples], it really narrows the field [of possible suspects],” says Jacobsen, who has been following the anthrax investigations keenly. “Polymerized glasses are exotic materials, and nanotechnology is something you just don't do in your basement.”

    By March 2002, federal investigators had lab results indicating that the Senate anthrax spores were treated with polymerized glass, and stories began to appear in the media. CNN reported an “unusual coating” on the spores, and Newsweek referred to a “chemical compound” that was “unknown to experts who have worked in the field for years.” When Science asked the FBI about the presence of polymerized glass in the Senate powder, an FBI spokesperson said the bureau “could not comment on an ongoing investigation.”


    By the fall of 2002, the awe-inspiring anthrax of the previous spring had morphed into something decidedly less fearsome. According to sources on Capitol Hill, FBI scientists now reported that there was “no additive” in the Senate anthrax at all. Alibek said he examined electron micrographs of the anthrax spores sent to Senator Daschle and saw no silica. “But I couldn't be absolutely sure,” Alibek says, “because I only saw three to five of these electron micrographs.” Even the astonishingly uniform particle size of 1.5 to 3 micrometers, mentioned in 2001 by Senator Bill Frist (R-TN), now included whopping 100-micrometer agglomerates, according to the new FBI description recounted by Capitol Hill aides. The reversal was so extreme that the former chief biological weapons inspector for the United Nations Special Commission, Richard Spertzel, found it hard to accept. “No silica, big particles, manual milling,” he says: “That's what they're saying now, and that radically contradicts everything we were told during the first year of this investigation.”

    In the cold.

    The U.S. Justice Department revealed that it was investigating scientist Steven Hatfill (bottom), formerly of Fort Detrick, and searched a nearby pond for clues.


    Military scientists did not back off their findings. The August/October 2002 newsletter from the Armed Forces Institute of Pathology (AFIP) reported that a mass spectrometry analysis found silica in the powder sent to Senator Daschle (The AFIP Letter, August/October 2002, p. 6). “This was a key component,” said the institute's deputy director, Florabel Mullick, in the AFIP newsletter. “Silica prevents the anthrax from aggregating, making it easier to aerosolize,” she added. Frank Johnson, chief of AFIP's Chemical Pathology Division, corroborated this in an interview. “There was silica there,” said Johnson, “there was no mistaking it.” Maj. Gen. John S. Parker, commander of the U.S. Army Medical Research and Materiel Command at the time of the attacks, says he saw AFIP's lab reports. “There was a huge silicon spike” consistent with the presence of silica, he says. “It peaked near the top of the screen.”

    Other agencies support this view today. For example, John Cicmanec, a scientist with the U.S. Environmental Protection Agency, says the Department of Homeland Security confirmed to EPA that the perpetrators did, in fact, use silica to weaponize the Senate anthrax spores. According to an abstract that Cicmanec will present at the annual meeting of the Society for Risk Analysis next month, this weaponized form of anthrax is more than 500 times more lethal than untreated spores.

    The contradictory military data compelled the FBI to do some explaining. Sources on Capitol Hill say that in an FBI background briefing given in late 2002, Dwight Adams, one of the FBI's top- ranking scientists, suggested that the silica discovered in the Senate anthrax was, in fact, silicon that occurred naturally in the organism's subsurface spore coats. To support his thesis, Adams cited a 1980 paper published by the Journal of Bacteriology—a paper that Matthew Meselson, a molecular biologist at Harvard University, says he sent to the FBI. The authors reported that they found silicon, the element, in the spore coats of a bacterium called B. cereus, a close cousin of anthrax.

    In the 23 years since the Journal of Bacteriology published these data, however, no other laboratory has published a report on significant amounts of silicon in the B. cereus spore coat, and many bacteriologists familiar with these data consider them an anomaly. Even the authors suggested the finding might have been due to “contamination.”

    In December 2002, the FBI decided to test whether a high-grade anthrax powder resembling the one mailed to the Senate could be made on a small budget, and without silica. To do this job, the bureau called upon Army scientists at Dugway Proving Ground, a desolate Army test range in southwestern Utah. By February 2003, the scientists at Dugway had finished their work. According to military sources with firsthand knowledge of this effort, the resulting powder “flew like penguins.” The experiment had failed. (Penguins can't fly.)

    Military sources say that Dugway washed and centrifuged the material four times to create a pure spore preparation, then dried it by solvent extraction and azeotropic distillation—a process developed by the U.S. Chemical Corps at Fort Detrick in the late 1950s. It is not a simple method, but someone familiar with it might be able to jury-rig a lab to get the job done. As recently as 1996, Bill Patrick says he taught scientists at Dugway how to do this.


    October 2001

    Letters loaded with anthrax powder reach the Senate.

    October 2001

    Army lab finds silica in Senate anthrax powder.

    April 2002

    Media reports “unusual coating” on Senate anthrax spores.

    May 2002

    JAMA paper says that spores were “weaponized” and “treated.”

    August 2002

    Attorney General John Ashcroft identifies Steven Hatfill as a “person of interest.”

    November 2002

    Capitol Hill aides told that “no silica” was found in Senate powder.

    December 2002

    FBI and Dugway try to reengineer Senate powder without silica.

    September 2003

    FBI official says that Dugway reengineering failed; regrets identifying Hatfill as a “person of interest.”

    The FBI-Dugway effort produced a coarse powder. The spores—some dried under an infrared lamp and the others air-dried—stuck together in little cakes, according to military sources, and then were sieved through “a fine steel mesh.” The resulting powder was placed into test tubes. When FBI officials arrived at Dugway to examine the results, a Dugway scientist shook one of the tubes. Unlike the electrostatically charged Senate anthrax spores that floated freely, the Dugway spores fell to the bottom of the test tube and stayed there. “That tells you the particles were too big,” says Spertzel. “It confirms what I've been saying all along: To make a good powder, you need an additive.”

    Close to home

    One doesn't have to look very far to find a powder that more closely resembles the Senate anthrax. The U.S. Army's newest batch of anthrax simulant is a closer match, made with B. globigii (BG) spores, which are similar to anthrax but nonlethal. According to military sources, the Danish company Chris-Hansen spray-dried the spores (along with an unidentified “additive”) in Valby, a suburb of Copenhagen. Although the spore count varied somewhat from batch to batch, Chris-Hansen says that the average concentration was 500 billion spores per gram, about 100 times more concentrated than the Army's old BG powder. Chris-Hansen shipped the bulk material from Denmark to its New Berlin, Wisconsin, facility in 1996, where, according to Army instructions, it mixed silica into the powder—a product sold commercially under the name Sipernat D 13. Sipernat D 13 is made by Germany's Degussa AG, the same company that makes Aerosil.

    The initial Chris-Hansen production run wasn't exactly what the Army wanted, military sources say, so this batch of anthrax simulant was further enhanced at Dugway Proving Ground. An official at Chris-Hansen, speaking on condition of anonymity, says he doesn't know if the Army added an electrostatic charge or a coupling agent to the powder, and the Army won't discuss it. But unlike the powder that Dugway reverse engineered earlier this year, the most recent batch of simulant—according to military sources—has great “hang time.”

    A government scientist who had a sample of the Army's anthrax simulant described it for Science: When he shook a test tube filled with it, a dense fog of particles swirled to the top in roiling eddies. After 10 minutes, the powder still hadn't settled. This scientist observed two other marked similarities with the Senate material: “There appears to be a lot of static charge,” he said. When he suspended the preparation in water, he saw mostly “single spores.” When Canadian military scientists used this silica-laced simulant in 2001 to assess the risk from anthrax spores delivered by letter, the aerosol behaved like the one that would later contaminate Senator Daschle's office with real anthrax spores; the weaponized BG particles spread across a 50-cubic-meter room in less than 2 minutes.

    They're back.

    Abandoned as a superpower weapon years ago, anthrax spores have returned as an instrument of terror.


    This new batch of “energetic” simulant was light-years beyond the old U.S. weapon in its refinement, experts say. Divulging the specifications of the weapon, the last foreman in charge of drying and milling anthrax spores at Fort Detrick, Donald Schattenberg, told Science that the old U.S. anthrax powder contained no additives. “We didn't use silica or bentonite” (a clay that contains a high percentage of fine-particulate silica), says Schattenberg. “We made little freeze-dried pellets of anthrax,” he says, “then we ground them down with a high-speed colloid mill.” The resulting powder contained growth media residue (called “menstruum”) and vegetative cells, making it less concentrated, according to William P. Walter, who says he worked on every batch of anthrax spores ever produced at Fort Detrick. This extraneous material accounted for a significant amount of the powder's volume and mass.

    Orley Bourland, who once managed the entire operation, says the old weapon had no electrostatic charge and contained only 20 billion to 30 billion spores per gram. These facts were corroborated by more than half a dozen veterans of the former U.S. weapons program, including Edgar “Bud” Larson, who scoffs at the suggestion that the Senate powder was the product of a secret one-man operation. “I think that's very unlikely,” Larson said. “I don't think anyone could make this product covertly.”

    So far, only Dugway Proving Ground has acknowledged making aerosols with Ames strain spores. According to a memorandum from U.S. Army Test and Evaluation Command dated 19 July 1995, Dugway began experiments with a liquid preparation of the Ames strain starting in February 1994. This was part of what the Army called “bioprofiling”: an effort to “establish a ‘library’ of information,” said the memo, to help defend against biological attack. In December 2001, The Baltimore Sun broke the story that Dugway had been making dried anthrax using live spores, and The Washington Post reported that Dugway used the Ames strain in its anthrax powders. Dugway released a statement acknowledging that its scientists have been doing this work to develop an “effective bioaerosol collection” but insisted that “All anthrax used at Dugway has been accounted for.”

    The Battelle Memorial Institute, a nonprofit organization based in Columbus, Ohio, is possibly the only corporation in the world known to possess both the Ames strain as well as a “national security division” offering the services of a team of “engineers, chemists, microbiologists, and aerosol scientists supported by state-of-the-art laboratories to conduct research in the fields of bioaerosol science and technology.” On its Web site, Battelle calls this research group “one-of-a-kind.”

    As subcontractors, Battelle scientists have made anthrax powders for use by the Army and U.S. intelligence agencies, but rarely by Fort Detrick, which specializes in vaccine development. Charles Dasey, spokesperson for the parent agency, the U.S. Army Medical Research and Materiel Command, says that as far as he is aware, the only dried anthrax spores made at Fort Detrick since it stopped making weapons were made by Battelle scientists working there for DARPA. This material, made in a biosafety level 3 suite in the Diagnostic Systems Division, contained killed Ames strain at a concentration of 326 million spores per gram—several orders of magnitude less concentrated than the Senate powder and crude by current standards.

    Battelle is capable of more sophisticated work, as it also makes one of the world's most advanced medicinal powders. Battelle's pharmaceutical division, BattellePharma, also in Columbus, is one of the few companies anywhere developing electrostatically charged aerosols for inhalation. BattellePharma's Web site boasts that the company's new “electrohydrodynamic” aerosol “reliably delivers more than 80% of the drug to the lungs in a soft (isokinetic) cloud of uniformly sized particles.” Other powders, boasts the Web site, only achieve 20% or less.

    None of this argues that Battelle or any of its employees made the Senate anthrax powder. But it is evidence that Battelle was a logical place to start looking for clues. Officials from Battelle and the Army declined to comment on any aspect of anthrax powder manufacture.

    The FBI says it has interviewed and polygraphed scientists working at both Dugway and Battelle. No “person of interest” at either facility has been named, and no evidence has been made public indicating either as a point of origin.

    A dose of reality

    Today, there is no firm evidence to link Iraq—or any other government—to the anthrax attacks. But some weapons experts such as Spertzel are still inclined to look for a sponsor with deep pockets, and they say Hussein's regime cannot be ruled out. Spertzel's main point, however, is that only a state-run facility or a corporation has the resources to make an anthrax powder as good as the one mailed to the Senate.

    The amateur anthrax scenario appears to have lost some credibility with the failure of the FBI's attempt to reverse engineer a high-quality powder using basic equipment. If the Army couldn't do it in a top-notch laboratory staffed by scientists trained to make anthrax powders, skeptics ask, who could do it in a garage or basement?

    The silica dust might still provide a trail to the killers, say chemists who specialize in silica. According to military sources, since the abandonment of the offensive biological warfare program, the U.S. Army has continued to experiment with various brands of silica nanoparticles added to germ-warfare powders produced in small quantities. These include WR-50 and WR-51 (manufactured by Philadelphia Quartz Co.), Cab-O-Sil (Cabot Corp.), and Sipernat D 13 (Degussa AG). Each brand is made differently, so each has a unique chemical signature, says Jonathan L. Bass, a Pennsylvania-based analytical chemist who used to do research with silica at PQ Corp. (formerly Philadelphia Quartz). “It'd be a laborious process, and some of the differences would be hard to detect,” says Bass, “but if a known brand of silica was used by the killers, I think I could trace it back to a specific company.” A coupling agent should also provide a unique chemical signature that could narrow the field.

    Two years on from the attacks, public discussion of the silica additive has all but ceased; the discussion about polymerized glass has yet to occur. Instead, the FBI has devoted much of its effort to the idea that a low-budget amateur operation could have produced a “weaponized” form of anthrax powder without a sophisticated additive.

    “ARE YOU AFRAID?” asked our unknown assailants 2 years ago. “Yes,” is still the answer, but of whom?


    To B or Not to B?

    1. Adrian Cho*
    1. Adrian Cho is a freelance writer in Grosse Pointe Woods, Michigan.

    To compare matter and antimatter, physicists hope to use Fermilab's gigantic atom smasher to study particles called B mesons. But can they afford the machine's last hurrah?

    Good things may come to those who wait, but don't try telling that to physicist Joel Butler. A researcher at the Fermi National Accelerator Laboratory (Fermilab) in Batavia, Illinois, Butler has been stumping for more than a decade to use the laboratory's enormous Tevatron collider to study the subtle flaw in the mirrorlike symmetry between matter and antimatter, an imbalance without which the universe would remain void. All Butler and colleagues need is a detector specifically designed to snare particles called B mesons—whose behavior may already be hinting at new particles, and which the Tevatron pumps out by the billions each year anyway.

    But although two other laboratories have devoted themselves to cranking out B mesons and researchers plan to study them at a gargantuan collider currently under construction in Europe, physicists working on the Fermilab project have found themselves mired in reviews, redesigns, and political wrangling. In 2000, lab management approved plans for the new detector, known as BTeV, which should be able to measure matter-antimatter asymmetries better than the other experiments. But the U.S. Department of Energy (DOE), which funds Fermilab, has yet to ask Congress to fund BTeV's construction. “It's really up to the DOE to give us the green light,” Butler says. “In a sense, we've been waiting for three-and-a-half years.”

    Things are looking up for BTeV, however. In October, DOE's High Energy Physics Advisory Panel (HEPAP) urged the department to fund and accelerate the $140 million project. And on 10 November, DOE listed BTeV among the 28 major facilities it hopes to build within the next 2 decades (Science, 14 November, p. 1126). Still, DOE has yet to show researchers the money, and some worry that, with work on the European collider proceeding apace, time is running out. “If we don't get started in 2005 we're out of business, because we've got competition,” says Sheldon Stone of Syracuse University in New York.

    Going my way?

    The 15-meter-long BTeV detector, shown here in an artist's conception, would straddle Fermilab's Tevatron collider (blue line) and would snag B mesons moving to the right.


    BTeV researchers hope to start taking data in 2009, 2 years after the Large Hadron Collider (LHC) at the European particle physics laboratory CERN near Geneva, Switzerland, revs up. BTeV would then be the only particle detector running at the Tevatron, which currently supplies particle collisions for two detectors, CDF and D0, that are searching for exotic new particles. But far more is at stake than the fate of the aging collider, says Fermilab director Michael Witherell. “BTeV could be the only experiment approved this decade for a U.S. accelerator,” Witherell says. “To not do it would really send a message of backing off high-energy physics.”

    Angling for antimatter

    Life, the universe, and everything owes its existence to the fact that matter and antimatter aren't quite exact opposites. Known as CP violation, that imbalance explains why, in the moments after the big bang, matter and antimatter did not annihilate one another and leave the cosmos empty. Thanks to CP violation, a little matter remained to form nuclei and atoms, stars and galaxies, physicists and DOE officials.

    CP violation was discovered in 1964, when researchers observed that particles called K mesons decay in ways not precisely mimicked by anti-K mesons. Over the past 4 decades, physicists have developed a theory known as the Standard Model, which posits that the protons and neutrons in atomic nuclei consist of fundamental particles called up quarks and down quarks. These particles have two sets of more massive cousins, the charm and strange quarks and top and bottom quarks. Quarks and antiquarks bind to make most of the particles physicists observe in the immediate debris of high-energy particle collisions. For example, a K meson consists of a strange antiquark and an up or a down quark, and a B meson consists of a much more massive bottom antiquark and an up or a down quark.

    The heavier quarks decay into lighter ones with certain probabilities, which depend on a handful of angles with which physicists describe how far matter and antimatter are out of kilter. Using the K meson data, theorists predicted that one of these angles, known as beta (β), should be measurable in the decays of B mesons. So in the 1990s, experimenters at the Stanford Linear Accelerator Center (SLAC) in Menlo Park, California, and at the Japanese High Energy Accelerator Research Organization (KEK) in Tsukuba tailored their electron-antielectron colliders to produce copious B mesons. In 2002, they announced that, as expected, β measured roughly 23 degrees.

    But although those measurements represent a victory for the Standard Model, physicists are hoping for more. If the theory accounts for all the particles there are, the sum of β and two other angles known as alpha (α) and gamma (γ) should equal 180 degrees, like the angles in a triangle. So researchers would like to measure the other angles to check this abstract “unitarity triangle.” Deviations from the expected results could signal the subtle influence of new particles, such as those predicted by a theory known as supersymmetry.

    Last laps?

    Fermilab's Tevatron (top ring) will provide B mesons for BTeV starting in 2009. Or it may be shut down entirely.


    In fact, earlier this year researchers at KEK announced that the measured value of β might depend on precisely how the B mesons decay, which itself could be a first hint of supersymmetry (Science, 22 August, p. 1026). And that's good news for physicists, as they know that the Standard Model alone does not contain enough CP violation to explain the predominance of matter in the universe.

    The “B factories” at KEK and SLAC cannot produce enough B mesons to nail down all the angles and probe the subtlest effects, however. That's why physicists need an experiment like BTeV, says JoAnne Hewett, a theorist at SLAC. “You can think of the present B factories as stage 1 of the B physics program and BTeV as stage 2,” she says.

    Trigger happy

    BTeV researchers plan to take advantage of the fact that the Tevatron collider produces far more B mesons than the colliders at SLAC and KEK can. Smashing electrons into antielectrons, the KEK machine cranks out roughly 20 B mesons per second, and the SLAC machine makes them at just over half that rate. By blasting protons into antiprotons at higher energies, the Tevatron could produce as many as 30,000 each second. Simultaneously, the collider will create cousins of the B mesons known as Bs mesons, which contain a bottom antiquark and a strange quark and will enable researchers to measure another important angle, chi (χ), that cannot be measured at SLAC and KEK.

    Finding all those extra B mesons is the hard part. Like quarks, the electron and antielectron are fundamental particles that contain no constituent “parts.” So when an electron and an antielectron collide, they annihilate each other completely and can produce exactly one B meson, one anti-B meson, and nothing else. That makes it easy for experimenters at SLAC and KEK to spot those particles when they decay in tiny firecracker-like explosions. In contrast, protons and antiprotons consist of quarks, antiquarks, and other particles called gluons. Most of these parts fly off when proton and antiproton collide, just as hubcaps and hood ornaments fly off cars during a crash. The B mesons produced by the Tevatron thus tend to get lost in a hail of other particles.

    To spot the B mesons amid the wreckage, BTeV researchers have designed a cutting-edge detector that can gobble data at an unprecedented rate. The B mesons travel several millimeters from the point of the initial collision before they decay into other particles, so BTeV researchers plan to use a high-tech “pixel detector” to track particles back to these little satellite explosions. Moreover, they have designed a superfast electronic system that will spot just about every collision that shows any sign of a B. This “trigger” requires several hundred microprocessors, making BTeV essentially a supercomputer with particles colliding inside it, says Dan Kaplan of the Illinois Institute of Technology in Chicago.

    The BTeV researchers are not the only ones planning to probe such messy collisions, however. CERN's LHC will smash protons into protons at even higher energies and will produce roughly five times as many B mesons as the Tevatron. Physicists at CERN are building a detector known as LHCb to study them. But LHCb will have a cruder trigger system than BTeV. Moreover, the detector at the more energetic machine will have to be much bigger than BTeV just to catch all the farther flung bits of matter, so it cannot be as fancy, says Tatsuya Nakada of CERN and the Swiss Federal Institute of Technology in Lausanne. “We certainly cannot afford to have a detector of as high a quality as BTeV would like to have,” he says. Researchers working on LHCb say that their detector should be good enough to get the job done, whereas those working on BTeV counter that their superior detector will surpass the competition—even if the CERN researchers get a 2-year head start on taking data.

    That's assuming that BTeV researchers get the money they need to put their plans into action. Officials at DOE's Office of Science won't say whether it's coming anytime soon. “We are encouraged that as a proposed experiment, [BTeV] is one of the best around,” says Robin Staffin, who directs DOE's high-energy physics program. “But there is no decision as of today whether to go ahead with construction.”

    Nonetheless, buoyed by last month's endorsement from HEPAP and their spot on the DOE major facilities report, BTeV researchers are optimistic. “I know Fermilab is ready to move on this. And I hope that the Office of Science is ready to move on this,” says Fermilab's Butler. “We expect good things.”

    But will those expectations ever be met? After years of waiting, that is still the question.


    No Garden-Variety Biologist

    1. Kathryn Brown

    A careful study of sunflowers has helped evolutionary biologist Loren Rieseberg plow new ground on how plant species emerge

    Coveted by gardeners, immortalized by Van Gogh, the sunflower is a universal beauty. And this beauty gets around; wild sunflowers frequently mate between species, popping up across forests, mountains, deserts, and even bracken salt marshes.

    For the past 15 years, evolutionary biologist Loren Rieseberg, 42, has tapped the wild sunflower to explore a classic scientific question: How do new plant species emerge? To find out, his lab at Indiana University, Bloomington, marries molecular experiments with classic field studies to learn how radically different hybrid sunflowers arise and colonize new habitats. His efforts have earned several major academic prizes, and this fall brought him a $500,000 MacArthur Foundation “genius” grant.

    His peers credit Rieseberg for putting sunflowers on the evolutionary map alongside the fruit fly and finch. “It would be fair to say the sunflower has developed into the system for the speciation of plants, largely—or solely—because of Loren,” remarks John Burke, an evolutionary biologist at Vanderbilt University in Nashville, Tennessee.

    Rieseberg exudes a quiet yet constant energy. A runner by morning and sculptor by night, he combines research with the mentoring of more than a dozen graduate students and postdoctoral associates. Refraining from alcohol, meat, and loud emotion helps him stay on an even keel. His lack of glamour, jokes evolutionary biologist Michael Arnold of the University of Georgia in Athens, is the only thing that keeps his colleagues from turning green with envy.

    Growing up in British Columbia, Rieseberg literally acquired an early taste for plants. At 11, during a wilderness survival camp, he was the only child who enjoyed nibbling on fireweed stems and fern rhizomes. Later, during graduate school at Washington State University in the 1980s, Rieseberg discovered his life's work—hybridization in sunflowers—in the pages of evolutionary biologist Verne Grant's monograph Plant Speciation.

    Although scientists had long known that wild plants hybridize—or mate with plants from different species—most believed that the resulting hybrids were maladjusted, evolutionary dead ends that quickly died out. However, Grant, now a professor emeritus at the University of Texas, Austin, wrote that wild plant hybrids do evolve and prosper.

    Rieseberg was inspired. “Speciation theory was not doing a good job of accommodating what really happened in nature,” he says. One semester into graduate school, he proposed a dissertation on hybridization. “The problem was that people didn't have any direct evidence that hybridization contributes to adaptive evolution,” Rieseberg recalls.

    Wild work.

    From salt marshes to sand dunes and the desert floor, extreme environments offer new niches to wild sunflower hybrids, says Indiana University evolutionary biologist Loren Rieseberg


    Thanks to him, they do now. Over the past 15 years Rieseberg has documented the rise of successful wild sunflower hybrids (Science, 29 August, p. 1211). His lab has compared the genes, physiology, and physical traits of five species: two widespread parental species, Helianthus annuus and H. petiolaris, and three hybrid offspring that evolved between 60,000 and 200,000 years ago. Unlike their parents, the hybrid species—H. anomalus, H. deserticola, and H. paradoxus—favor extreme habitats: sand dunes, dry desert floor, and salt marshes, respectively.

    To capture this evolution in action, Rieseberg's team replicated it by creating their own hybrids of H. annuus and H. petiolaris in the greenhouse. They analyzed the resulting “neospecies” for the adaptive traits—such as genes that confer salt tolerance or succulent leaves—needed to colonize the extreme habitats of naturally evolved hybrid species. Working with more than 2000 various synthetic hybrid seedlings, they successfully transplanted them in salt marshes in New Mexico and sand dunes or desert floor in Utah.

    The DNA that drives hybrids is markedly different, too, Rieseberg and colleagues have shown. They used quantitative trait locus mapping—a method that taps molecular markers to find genes responsible for phenotypic traits such as leaf shape and seed size—to determine which combinations of alleles a plant has. Among sunflowers, the researchers confirmed that ordinary parent plants from temperate climates can indeed mate and yield hybrid offspring with hardier combinations of the same genes. These new gene combinations, they concluded, allowed the hybrids to colonize new ecological niches, such as salty and dry habitats.

    “Most evolutionary theory has focused on whether a particular process is possible or likely,” Rieseberg remarks. “We've tried to go beyond that to show what actually happened.” About 250,000 years ago, he suggests, buffalo began changing the face of North America by carving haphazard roads into the Great Plains and churning up the soil. They also carried sunflower seeds, helping them reach homes spatially and ecologically isolated from their floral parents.

    Some questions linger. Which mutations, in particular, yielded the hardy genes that allow hybrid sunflowers to thrive in parched or salty conditions? How did hybrids so rapidly acquire big shifts in their chromosome arrangements? And, on a related point, how—and when and where—were sunflowers domesticated?

    Rieseberg's team is tackling all these questions. “We suspect hybridization is important in larger, or difficult, evolutionary transitions,” he explains. “The idea is that hybridization generates variation at hundreds or thousands of genes simultaneously.”

    Few doubt that Rieseberg will answer these and other important questions in the years ahead. “He's built such a marvelous system, and each year or two, you can see it unfolding, deeper and deeper,” remarks Indiana University colleague Jeffrey Palmer. “Loren's at the cutting edge of several fields, so the best is probably yet to come.”