News this Week

Science  04 Jul 2008:
Vol. 321, Issue 5885, pp. 22
  1. FLORIDA

    Big Land Purchase Triggers Review of Plans to Restore Everglades

    1. Erik Stokstad

    An $11 billion plan to restore the Everglades will likely get an overhaul after a major land deal last week by the state of Florida. The state's $1.75 billion purchase is intended to create wetlands that will speed up the delivery of water to the thirsty ecosystem. Environmentalists hope the two main players in the 8-year-old Comprehensive Everglades Restoration Plan—the state's South Florida Water Management District (SFWMD) and the U.S. Army Corps of Engineers—will now abandon a costly and unproven plan to store Everglades-bound water in aquifers.

    Scientists say the new approach is simpler, cheaper, and big enough to accelerate recovery of the Everglades. In buying out U.S. Sugar Corp., the largest sugar cane producer in the nation, the state would recreate strategically located wetlands that could store nearly 1.2 cubic kilometers of water. “The sheer magnitude of it is beyond our wildest dreams,” says Kirk Fordham, chief executive officer of the Everglades Foundation, an advocacy group based in Palmetto Bay, Florida.

    Many technical and political hurdles lurk beneath the surface of the deal, however. Some of the land must be swapped with other landowners to create a large contiguous area. Improving water quality will be a big challenge. And with SFWMD spending 20% of its restoration dollars on buying land, other projects will need to be delayed or halted. The Army Corps of Engineers will also need to review its priorities, and advocates hope the agency will focus on helping the water travel south.

    The Everglades needs all the water it can get. Once spanning more than 10,000 square kilometers, the wetlands were drained for agriculture and divided by roads and flood-control canals. Now less than half of the estimated 2 million cubic kilometers of water per year that used to flow south from Lake Okeechobee reaches the Everglades.

    Due south of the lake, U.S. Sugar's land occupies a strategic position for restoring water flow. Under the terms of the purchase, farming will continue for 6 years while the water district negotiates land swaps with other farmers in the area to consolidate the holdings. Then engineers will flood the land.

    This means it won't be necessary, as in past wet seasons, to drain lake water seaward to prevent flooding of nearby lands. Instead, the water will be retained in new wetlands and sent south in the dry season. This approach will also reduce harm on the east and west coasts, where outflows altered the salinity of the estuaries and covered oyster beds with muck. The new storage capacity “gives us a lot more flexibility,” says Tommy Stroud, the district's chief of operations.

    The existing restoration plan is flawed, some say, and needs to change. It calls for water to be pumped from Lake Okeechobee into aquifers during the summer, then pumped out in the winter. Reviews by the U.S. National Academies pointed out technical problems and risks (Science, 9 February 2001, p. 959), and observers expect that the idea will now be ditched.

    Before sending water south, the path to the Everglades must be clear. Federally run restoration projects south of the new wetlands include building channels and bridges on U.S. Route 41, which runs along an east-west levee, and filling in or reengineering canals in the Wetland Conservation Areas (WCAs). Both projects will now need to go faster, says John Ogden of Audubon of Florida. Ogden estimates that the annual $165 million federal contribution will need to be roughly doubled to get the job done.

    The new plan faces other hurdles. The compacted soil in the Everglades Agricultural Area now lies a few meters below the Everglades. That means water will have to be pumped into the WCAs. Ecologist Stuart Pimm of Duke University in Durham, North Carolina, worries that the Army Corps of Engineers may go overboard in designing an engineering solution “that won't have ecological benefits for decades.”

    Water quality could be a problem, too. The land deal will eventually end the use of phosphorous fertilizer on U.S. Sugar's fields, which has caused eutrophication in the Everglades, and sulfate that has exacerbated mercury contamination in fish. However, both compounds remain in the soil, and still more will enter the wetlands along with water from the lake, where the sediments are highly contaminated. Aquatic plants in so-called stormwater treatment areas (see map) can remove the phosphorus but only if they are in shallow water.

    Sweet deal.

    The purchase of sugar-cane fields (red) will allow Florida to assemble land for new wetlands, which will send water to the Everglades.

    SOURCE: U.S. SUGAR CORP.

    Water district officials hope to finalize the deal by 30 November and begin consulting with stakeholders. Meanwhile, advocates are savoring the moment. “No one imagined we could do anything like this,” says Paul Gray of Audubon of Florida. “We're in a whole new era of water management.”

  2. CLIMATE CHANGE

    California Emissions Plan to Explore Use of Offsets

    1. Eli Kintisch

    Energy giant Pacific Gas and Electric Co. (PG&E) found a unique source of green energy last year: 5000 dairy cows on a farm near Riverdale in central California. By collecting methane from manure and turning it into natural gas for home use or electricity, officials hope to prevent the yearly emission of 1200 tons of methane, a greenhouse gas 21 times more potent than carbon dioxide (CO2).

    Scientists and activists applaud the company's creative effort to combat global warming. But the utility wants more than accolades. It would like bankable credit—and just might get it under rules California began drafting last week.

    The plan, the most aggressive in the country, is to achieve a 10% cut in the state's current greenhouse gas emissions by 2020. A key mechanism is a system that caps the amount of emissions allowed and then permits trading in emissions credits. The system, which would begin next year, would cover everything from automobiles to power plants to factories. PG&E thinks its biogas project should offset part of the anticipated reductions that it would be required to make in emissions from its natural gas and coal facilities.

    But calculating the impact of such offset projects is one of the thorniest problems facing California officials. “It's a hard question for [them],” says offsets critic Michael Wara, a former geochemist who teaches law at Stanford University in Palo Alto, California. The goal is to make sure that every dollar spent under the cap has the greatest benefit. So the challenge, he says, is to prevent companies from getting credit for “what would've happened without the incentive created by the carbon market.” And how state officials deal with offsets could set a national precedent.

    Offset projects are intended to encourage big emitters to reduce expected emissions cheaply and in a way that spreads the wealth. Under the Kyoto Protocol's offset program, called the Clean Development Mechanism (CDM), emitters in developed countries have purchased roughly $19 billion in credits for efforts such as forestry, agriculture, or green power projects in developing countries. Whether a company cuts emissions at a German power plant or a Chinese forest is immaterial, the thinking goes. “A ton is a ton is a ton,” says PG&E official Robert Parkhurst, who emphasizes the need for a well-regulated system. “The endgame in this is reducing tons of greenhouse gas.”

    Early moo-vers.

    A California utility wants credit under a new emissions cap to collect and process methane from cow manure.

    CREDIT: GARY KAZANJIAN/AP PHOTO; (INSET) PG&E

    But experts wonder if emissions cuts claimed under CDM are really offsets or if the reductions would have happened anyway. Government incentives due to energy shortages, for example, have led to a building spree in China of low-carbon energy sources, including dams, wind power, and natural gas plants. Yet in their CDM applications, Chinese developers have claimed that Kyoto credits are the driving force behind the projects rather than pressure from the government and the expected economic payoff. Likewise, Axel Michaelowa of Germany's Hamburg Institute of International Economics has found that proposals for wind farms in India systematically left out generous government tax incentives. Stanford's David Victor estimates that up to two-thirds of emissions cuts under CDM represent cuts that would have happened anyway.

    Offsets may have another flaw: They divert to inefficient projects money that could be used to cut emissions directly, critics say. For example, Chinese developers have received $7.4 billion worth of CDM credits in return for preventing the release into the atmosphere of roughly 6600 tons of a gas called trifluoro-methane, a greenhouse gas 11,700 times more potent than CO2 created during the manufacture of refrigerants. But Victor and Wara found that destroying the same amount of the gas would have cost only $157 million. This “perverse incentive,” they wrote in an April paper, has fostered an industry devoted to creating the waste gas so that it can then be eliminated for cash. Worse, the extra $7.2 billion diverted to the effort could have been spent by big emitters to make real emissions cuts.

    California officials, whose proposed system would cover 85% of the state's greenhouse gas emissions, say offsets could “spur innovation in unregulated sectors” such as agriculture and imported cement. They say their regulations and oversight will be stricter than CDM's, although a detailed plan won't be issued until October. In the meantime, Wara notes that California has already agreed to allow its industries to trade in emission certificates from its neighbors—some of whom are bound to accept CDM credits, tainted or not—under the 10-state Western Climate Initiative launched last year. “We are really excited about [PG&E] doing this project,” says attorney Kristin Grenfell of the Natural Resources Defense Council's San Francisco office. “We just don't think that offsets are the best way of encouraging it.”

  3. PALEONTOLOGY

    Life's Innovations Let It Diversify, at Least Up to a Point

    1. Richard A. Kerr

    When paleontologists first seriously considered how life had evolved, the story looked simple: From a few basic types, organisms had diversified unhindered into myriad new forms over the past half-billion years. Then the bean counters got into the act. After correcting for sampling biases and other pitfalls in the fossil record, a group of quantitatively oriented paleontologists reported in 2001 that life at sea, at least, had followed a different course (Science, 25 May 2001, p. 1481). Although marine invertebrates had continued to innovate new ways of making a living, the scientists concluded, total diversity had hardly increased in 400 million years.

    Now the number crunchers have rewritten the prehistory books again. On page 97, 35 of them—including authors of the original paper—present a new analysis of the Paleobiology Database, which records about 3.5 million specimens described in papers of the past century and more. They conclude that the diversity of marine invertebrates has indeed increased over time, although far less than some early analysts believed. Paleontologists not involved in the new study say they agree with its general approach but doubt it will be the last word on the subject. “There's a lot of improvement in methodology, and there's a lot more data,” says David Jablonski of the University of Chicago in Illinois, who worked on the 2001 analysis but not the new one, “but there are still biases remaining in the data that remain to be addressed.”

    Diversity constrained?

    The latest curve of marine diversity lacks a recent sharp rise, suggesting something reined in evolution. Alternatively, excluding young fossils found in loose sediment (near left) may have damped the rise.

    CREDITS: (GRAPH) J. ALROY ET AL., SCIENCE; (IMAGES, TOP TO BOTTOM) D. L. MEYER/UNIVERSITY OF CINCINNATI; S. KOLBE

    Everyone agrees that the raw fossil record is flawed. For 180 years, paleontologists tended to collect their favorite fossils near their home institutions in North America and Europe, neglecting fossils in remote lands. They collected more and smaller fossils from young, loose sediments than they did from older rock. And of course they were more likely to collect the fossils that tended to be preserved rather the more vulnerable ones that fade away with time.

    The Paleobiology Database—compiled under the supervision of John Alroy of the University of California, Santa Barbara (UCSB)—includes information needed to correct such biases in the record, information such as exactly where in the record and in what sort of rock each fossil was found. Alroy, lead author of both the 2001 study and the new paper, says both groups also applied statistical techniques as they “sampled” the database to ensure that their count resembled reality. Unfortunately, he says, the 2001 team made some assumptions about sampling that “turned out to be dramatically wrong” in ways that would have made an increase in diversity through time hard to find. The new analysis corrects those errors, he says. It's also based on four times as much data spanning all of the past 500 million years.

    The resulting graph of changing diversity over time resembles the pre-2001 curve in showing a steep rise in diversity in the first 100 million years. The curves differ most sharply in the past 65 million years, when diversity soars dramatically on the pre-2001 curve but hardly rises on the new one. As a result, the number of genera in geologically recent times appears to have increased only about 30% over life's early peak, not three- to fourfold as the old curve showed. Something has been constraining evolution and diversity for hundreds of millions of years, the group concludes—perhaps some bottleneck in the way energy moves up through the food chain in the global ecosystem.

    Although the latest diversity curve marks a big improvement over the 2001 effort, it may go too far, says paleontologist Richard Bambach of the Smithsonian National Museum of Natural History in Washington, D.C., another co-author of the earlier paper but not of the current one. “We're getting into the ballpark, [but] they're taking the most conservative approach,” he says. The newly estimated diversity of the past 10 million years in particular may be “excessively conservative,” he says.

    For one thing, Bambach says, the group excludes all fossils recovered from sediments that have not yet turned to stone. That makes sense in principle, he explains. Because sieving loose sediments for fossils is so much easier than breaking rocks, including fossils from silt and mud could inflate the apparent diversity of more recent times, when most such “unlithified” sediments are found. On the other hand, if diversity really has increased recently, ignoring younger samples could seriously undercount it, Bambach says. Jablonski also suspects that younger diversity is being missed in the western tropical Pacific Ocean. Today, shellfish are wildly diverse there, he notes, but in the database they appear to be relatively impoverished only a few million years ago. More likely, he says, the database has yet to include the older literature from that region. Thus, some observers are looking for a third iteration of life's changing diversity.

  4. EVOLUTION

    Where Have All Thoreau's Flowers Gone?

    1. Elizabeth Pennisi

    Early in May, the oaks, hickories, maples, and other trees, just putting out amidst the pine woods around the pond, imparted a brightness like sunshine to the landscape. …

    These words from Walden hint at the careful plant and animal records Henry David Thoreau kept during his stay at Walden Pond in Concord, Massachusetts, in the mid-1800s. By retracing this young naturalist's footsteps, not once but twice in the past century, researchers have been able to chronicle the fate of hundreds of plant species as the New England climate has changed since Thoreau's time. Using that data, Harvard University graduate student Charles Willis and colleagues have detected a disturbing pattern, one that he described last week in Minneapolis, Minnesota, at the Evolution 2008 meeting.

    Flower man.

    Thoreau closely tracked Walden Pond plants

    CREDIT: COURTESY OF THE THOREAU INSTITUTE AT WALDEN WOODS

    By building a flora family tree that incorporates the “Thoreau” species and mapping onto the tree each plant's response to the 2°C increase in the region's average temperature since the famed author was at Walden Pond, the researchers have discovered that climate change has placed whole groups of plants at risk and that the more charismatic wildflowers that prompt conservation efforts, such as orchids, are among the most vulnerable.

    The study is “an intriguing combination of historical data sets and modern molecular methods to address in a very novel way climate change effects,” says Carol Horvitz, a plant evolutionary ecologist at the University of Miami, Florida. “I think it's brilliant.”

    Many studies have looked at how global warming may cause shifts in where plants grow, but very few have examined how specific traits, such as flowering time, are affected. The necessary long-term records rarely exist. But for 6 years, Thoreau tracked the life histories of more than 400 plant species in a 67-square-kilometer area. Another researcher covered the same ground at Walden Pond and its surrounds circa 1900. Then from 2004 to 2007, Boston University (BU) conservation biologist Richard Primack and his student Abraham Miller-Rushing regularly visited the area to make similar observations of about 350 species and to check how the abundances of these plants had changed through time.

    Their data, published in February in Ecology, revealed that many flowers were blossoming a week earlier than in Thoreau's time. They noted also that about half of the species studied had decreased in number, with 20% having disappeared entirely.

    Working with his Harvard adviser Charles Davis, the BU group, and fellow Harvard graduate student Brad Ruhfel, Willis has put these data into an evolutionary context by looking at how closely related the affected species were. They pieced together a family tree of more than 500 species and noted changes in their range, abundance, and other traits—such as which had flowering times that were tied to spring temperatures and which did not. In this way, they could check to see if there was a correlation between flowering time and how well a species fared over 1.5 centuries.

    Climate shift.

    The warming of the Walden Pond area (above) since the 1880s threatens many plants.

    CREDIT: JOSEPH SOHM/VISIONS OF AMERICA/CORBIS

    “Certain [groups] were very sensitive,” Willis reported at the meeting. A plant's ability to change its flowering time depending on the spring weather in a given year proved a key predictor of its current health. “Species that had not shifted [flowering times] are declining in abundance.”

    Wildflowers with more northern ranges proved the least flexible. Thus irises, orchids, lilies, and bladderworts were among the plants that had declined the most—they tended to flower the same time of year, regardless of the weather. “That climate change is affecting whole sets of species differently is intrinsically interesting,” says Horvitz.

    Rare as they may be, these sorts of analyses can help researchers predict which species are threatened most by global warming and which are likely to adapt, says George Weiblen, an evolutionary biologist at the University of Minnesota, Minneapolis. “Finally, evolutionary biologists are chiming in on the effects of climate change.”

  5. GENOMICS

    Billion-Dollar Cancer Mapping Project Steps Forward

    1. Jocelyn Kaiser

    Leaders of an ambitious effort to find all common mutations in human cancers delivered their first results to a U.S. government panel last week along with a plain message: Their $100 million pilot is paying off. A sweeping search for mutations in one cancer—glioblastoma, a type of brain tumor—has verified known genes and turned up a few new ones, said lead presenter Eric Lander of the Broad Institute in Cambridge, Massachusetts. The data from DNA sequencing of tumors, combined with other genetic analyses, he said, are already pointing to potential new therapies to extend the lives of glioblastoma patients, who now rarely survive much longer than a year.

    Target number one.

    Glioblastoma, a cancer of the brain, was studied in a pilot gene-sequencing project.

    CREDIT: ARTHUR TOGA/UCLA/PHOTO RESEARCHERS INC.

    Lander and others were making the case for a massive, multiteam endeavor on the scale of the Human Genome Project, known as The Cancer Genome Atlas (TCGA). First proposed by Lander 3 years ago, TCGA would aim to find all common mutations in the major human cancers over 10 years, at a cost of up to $1.5 billion. After some scientists panned the idea as not worth the price tag (Science, 21 October 2005, p. 439), the National Cancer Institute (NCI) and the genome institute launched a 3-year pilot project.

    The audience for last week's pitch, NCI's Board of Scientific Advisors (BSA), was listening on this occasion, not voting. But at least one member who calls himself a former skeptic—Lee Hartwell of the Fred Hutchinson Cancer Research Center in Seattle, Washington—says he was impressed: “At this early stage, to come up with something that essentially changes how we think about [glioblastoma] therapy is pretty phenomenal.”

    Lander summed up the search for genes involved in glioblastoma, the first of three cancer types under investigation. After sequencing 600 candidate genes in 86 samples, TCGA has verified five genes already known to be mutated in glioblastoma and found three new ones, including NF1, which seems quite important—this gene was inactivated in 20% of the samples. Other teams, who are combining these genes with data on gene expression and gene copy number, report that primary glioblastoma appears to occur as three or four distinct subtypes. And Charles Perou of the University of North Carolina, Chapel Hill, noted that each subtype shows different patterns of mutations within key gene signaling pathways.

    These results suggest that clinicians could classify glioblastoma patients by their tumor types, then tailor therapy to the genes or pathways that matter most, reported neurosurgeon Cameron Brennan of Memorial Sloan-Kettering Cancer Center in New York City. He cautions, however, that not all the data are in hand.

    The BSA had some questions for the scientists. One member found it “unsettling” that patients with different subtypes all had the same survival rates. And chair Robert Young, president of Fox Chase Cancer Center in Philadelphia, Pennsylvania, says these early results probably won't win over some skeptics: “It's still debatable whether sequencing is the only or best way” of exploring the cancer genome, Young says. Still, “this first presentation is encouraging,” Young says. “It's doable.”

  6. MARINE BIOLOGY

    Panel to Take Closer Look at Scientific Whaling

    1. Dennis Normile

    Is Japan's research whaling, which claims about 1000 whales a year, scientific investigation or disguised commercial whaling? A new review process endorsed by the International Whaling Commission (IWC) at its 60th annual meeting held last week in Santiago, Chile, hopes to get closer to the answer.

    Departing from past practice, the review panel will likely include experts from outside IWC's Scientific Committee and exclude scientists involved in Japan's research. Even so, says John Frizell, a spokesperson for Greenpeace International, which has criticized Japan's effort, the results “will depend on who the outside experts are.”

    Unprotected.

    Japanese whalers capture short-finned pilot whales, which are not covered by a moratorium on commercial whaling.

    CREDIT: ISSEI KATO/REUTERS/LANDOV

    Japan carries out one hunt a year in Antarctic waters and another in the North Pacific. The Tokyo-based Institute of Cetacean Research (ICR) maintains that the animals must be killed to obtain data, such as age and stomach contents, needed to develop management plans for the resumption of commercial whaling. During 2008–09, Japan plans to take 1330 whales, primarily minke, with limited numbers of sei, Bryde's, sperm, and fin whales. The total, which includes 50 humpback whales, is more than all other countries kill for scientific, commercial, and subsistence purposes combined. But Japan has “postponed” its humpback catches pending further IWC discussions (Science, 27 April 2007, p. 532).

    Under IWC rules, the Scientific Committee reviews research programs before they begin and then every 6 years. In the past, Japanese scientists were part of that review team and helped write the reports. “That is not the way reviews are done in the real world,” says one Scientific Committee member, speaking on condition of anonymity.

    The new approach, adopted when the committee met in Santiago ahead of the annual meeting, will allow scientists conducting the research to present results and answer questions but not serve on the review panel. The process will be used to analyze Japan's ongoing North Pacific program next spring.

    In its report to IWC, the Scientific Committee says the changes are intended to improve the review process. But some also see it as implicit criticism of Japan's whaling program, with one committee member noting that they hope “to submit bad science to a proper review.” Dan Goodman, an adviser to ICR in Tokyo, says the institute hopes to use the results from the new review process to refine its research whaling program, which he says is “a right of every contracting government” under the IWC convention.

    Meanwhile, IWC has set up a new working group to propose compromises on divisive issues such as research whaling and creating whale sanctuaries. The group will begin its work long before the Scientific Committee completes its review, however.

  7. APPLIED PHYSICS

    Tiny Transistor Gets a Good Sorting Out

    1. Robert F. Service

    For electronics researchers, carbon nanotubes are like opera divas—full of power and headaches. The tiny, all-carbon tubes carry oodles of electric current for their size, and they can behave as either metals or semiconductors depending on their atomic arrangement. Electronic devices such as transistors and wires are best made with either semiconducting or metallic tubes, not both—yet, when produced, carbon nanotubes come out as a mix. Researchers have devised ways to separate and pattern different types of tubes. But so far, those schemes have been complex and hard to scale up. Now a California team may have hit upon a simple solution.

    On page 101, researchers at Stanford University in Palo Alto, California, led by chemical engineer Zhenan Bao report using different chemical compounds to attract metallic and semiconducting tubes to different areas on a surface. Using this approach, the researchers separated and patterned semiconducting tubes in one step to form the heart of a transistor that turned off and on much more efficiently than previous transistors made with bunches of nanotubes. “This is good work” and an “important piece” toward the overall goal of integrating carbon nanotubes into high-performance electronics, says Jeffrey Bokor, an electrical engineer at the University of California, Berkeley.

    Electrical engineers have turned to carbon nanotubes and other materials in recent years as the push to make ever-smaller transistors continues to reduce the amount of current that silicon can shuttle in the critical channel between electrodes. Given their ability to carry large currents, carbon nanotubes may do better. But to make good devices, researchers must span the electrodes with tightly packed rafts of nanotubes. Those rafts must contain only semiconducting tubes, not metallic ones, which can't switch on and off.

    Chemical thresher.

    New way of making transistors with carbon nanotubes uses phenyl groups to attract metallic tubes (blue), while amines grab semiconducting tubes (red).

    CREDIT: Z. BAO/STANFORD UNIVERSITY

    Prior research groups have come up with schemes to lay down both types and then burn out the metallic tubes, leaving the semiconductors behind. Another technique separates the two in solution before patterning them. In their current work, Bao and her colleagues combined the separation and patterning in one. They patterned a substrate with simple compounds called amines that then attracted just the semiconducting tubes to lie down and bind. Washing the surface removed any metallic tubes and aligned the semiconducting ones in the channels between electrodes. The result was individual transistors that, unlike many previous devices, conducted far better when switched on than they did when turned off.

    The next step for Bao's group and others, Bokor says, is to pack more tubes in the channels to carry more current. If they do that, nanotube transistors may soon give silicon a run for its money.

  8. ARCHAEOLOGY

    Preserving Iraq's Battered Heritage

    1. Andrew Lawler

    Archaeologists have feared for Iraq's unique archaeological treasures since war began 5 years ago. Now, despite continued unrest, a team returning from southern Iraq bears surprisingly good news.

    Archaeologists have feared for Iraq's unique archaeological treasures since war began 5 years ago. Now, despite continued unrest, a team returning from southern Iraq bears surprisingly good news

    In the early morning light of 7 June, an international team of archaeologists examined the ancient settlement of Tell al-Lahm in the flat and fertile plain of southern Iraq for signs of looting. Then three pickup trucks with armed men suddenly arrived on the scene. What followed was a brief but welcome confrontation: The men were part of a security team tasked with protecting such lonely sites from artifact thieves. Five years after the U.S. invasion of Iraq and the overthrow of Saddam Hussein plunged the country into chaos and sparked a looting spree, a semblance of order is returning to the home of humanity's first writing system, cities, and empires. The team—the only group of scholars allowed to visit the area since the summer of 2003—found guards patrolling several sites and little evidence of extensive theft in recent years. “It's really good news after so many years of doom and gloom,” says archaeologist and team member Elizabeth Stone of Stony Brook University in New York state.

    Overturned.

    Looters decimated the ancient Sumerian city of Kisurran in southern Iraq, as seen by turned earth (brown) in the second satellite image.

    CREDIT: DIGITAL GLOBE/ELIZABETH STONE

    That good news extends to Amman, Damascus, and New York, where investigators succeeded recently in recovering thousands of artifacts stolen from Iraq after the invasion. European governments are also moving, albeit slowly, to help rehabilitate Iraq's shattered museums, rebuild fences at exposed sites, and provide remote-sensing data to researchers. Serious difficulties remain. Iraqi archaeologists trying to protect priceless artifacts and ancient settlements still face intimidation and even jail time (see sidebar, p. 29). Allied troops damaged some of the most famous cities of the ancient world and have yet to address the problems. And the international market in Mesopotamian antiquities continues to thrive, likely fueled by continued looting at smaller and more remote sites. But archaeologists are finally gaining access to the region, allowing them to make realistic appraisals and recommend action.

    Ground truth.

    John Curtis documents damage to a Kassite structure at Ur, next to a U.S. air base.

    CREDIT: BRITISH MINISTRY OF DEFENSE

    Sky view, ground truth

    Before the trip, archaeologists had already seen signs of widespread looting, primarily with the help of satellite data. In a paper in the March issue of Antiquity, Stone used remote-sensing images to examine 101 square kilometers of archaeological sites in southern Iraq. She found nearly 16 square kilometers of looting holes in that area—four times the amount of legal excavations conducted in the same areas during the past century. Much of the looting appears to have taken place during two periods. The first was in the mid-1990s—a time of desperate poverty in southern Iraq—and the second during the spring and summer of 2003, when allied troops were fighting Saddam's army and then the growing insurgency.

    But until last month's expedition, no team of foreign archaeologists had actually been on the ground in southern Iraq since mid-2003. The group, which planned to reveal its findings at a 4 July press conference in London, included researchers from the United States, the United Kingdom, and Germany, as well as two Iraqi officials. They were sponsored by the British military, which provided a helicopter and security team. During their 3-day visit, the researchers visited and assessed eight major sites, including Eridu, home of an early temple complex, and Uruk, where legend says the world's first writing system, cuneiform, was developed. “It was not as bleak as we feared,” says John Curtis, an archaeologist at the British Museum in London who took part.

    The major exception was Ur, famed center of a Sumerian city-state 4 millennia ago and home to a partially reconstructed ziggurat. A large American air base sits immediately adjacent to the site, which has drawn hordes of visiting American soldiers. The result is extensive wear and tear, team members say. For example, a building from the Kassite era, circa 1400 B.C.E., is in danger of collapse. “One of the earliest arches in the world is going to fall down,” says Stone. American engineers also bulldozed a nearby 2nd millennium B.C.E. site as part of a base expansion between August 2004 and August 2005, team members say.

    The base's location violates a decree by Iraq's State Board of Antiquities and Heritage mandating a 500-meter-wide protective zone around archaeological sites. But U.S. State Department spokesperson William Olson in Baghdad refused to comment on any damage sustained at Ur or on whether the U.S. government intends to fund security or restoration projects there. Curtis says the British government may seek money to fix some of the most egregious damage at Ur and other southern sites.

    Consistent security has helped preserve nearby Uruk, where King Gilgamesh is said to have reigned. One guard is paid by the German government, and 15 more are part of the Iraqi Facilities Protection Service (FPS) set up in 2003 to protect Iraqi government sites. Margarete van Ess, an archaeologist at the German Archaeological Institute in Berlin and the third Western member of the team, was delighted to find her pottery and excavation materials intact in the dig house. “I guess I could go there and restart my research,” she says, adding that she hopes to return once the situation is less dangerous.

    Curtis, Van Ess, and Stone say they were heartened by the FPS guards who confronted them briefly at Tell al-Lahm. FPS has been accused within Iraq of becoming a militialike organization, but archaeologists say they are grateful for their presence. “It is very encouraging that the efforts to protect sites really have worked,” adds Stone. But Abdel-Amir Hamdani, Iraq State Board of Antiquities inspector in the Nasiriyeh region, says the Iraq government has refused to provide fuel since 2006 for FPS patrols, hampering their effectiveness.

    Spy operation

    The three archaeologists agree that their limited visit provides little new data on the host of other sites in southern Iraq that satellite data suggest may still be plagued by looting. Hamdani says that smaller and more remote sites are especially vulnerable. The international team was unable to visit any of these sites, although Stone confirmed that remote-sensing images show widespread damage to ancient settlements in the area.

    Lacking the firepower to take on the often-armed bands that denude sites, Hamdani has tried to recover some of their plunder and catch the ringleaders by posing as a buyer at two villages known as centers of the black market, El Fajir and Albhagir, on the northern border of Dhi Qar governate. During one visit, a village boy asked him what kind of artifacts he wanted—gold objects, tablets, statues—and led him to the appropriate dealer. Hamdani was then able to tip off Italian soldiers and Iraqi police. In a single home, they discovered 600 artifacts, including pots and cuneiform tablets. Albhagir was once a typical small and impoverished southern Iraqi village, says Hamdani. Now it boasts large homes that he suspects are funded with money from the illegal trade. “Some 70% of the population work in looting and smuggling artifacts,” he estimates. “He's now running a spy operation” using informants, says Stone with admiration.

    But sometimes a successful sting operation isn't enough. In November 2004, for example, a truck carrying recovered looted material on its way to the Iraq Museum in Baghdad was hijacked, the driver and guards killed, and the artifacts stolen.

    Market of thieves.

    These looted antiquities were confiscated in a small town in southern Iraq, where business in artifacts is brisk.

    CREDIT: ABDEL-AMIR HAMDANI/SBA

    Thousands of looted objects have slipped across Iraq's porous borders since 2003, stolen from the Iraq Museum or looted from illegal digs. Now some, at least, are on the road back to Iraq. Syrian officials in April seized 700 artifacts from smugglers and dealers and sent them back to Iraq. Just last week, Jordan announced the repatriation of 2400 artifacts seized by customs authorities in antismuggling operations. John Russell, an archaeologist at the Massachusetts College of Art in Boston who is consulting with the U.S. State Department, says that about 1000 artifacts—including tablets, cylinder seals, and glass bottles—intercepted by customs officials will be turned over soon to the Iraq Embassy in Washington, D.C.

    Meanwhile, efforts are under way to restore Iraq's fraying network of regional museums. Italy is working to rehabilitate several, and Curtis says the British military may provide $20 million to convert one of Saddam's palaces in Basra into a museum.

    One of the most frustrating tasks confronting archaeologists concerns the ancient capital of Babylon, located 85 kilometers south of Baghdad. It was a major player in Middle Eastern history from the 23rd century B.C.E. until just before the time of Christ. American and Polish troops damaged parts of the metropolis while building a military base there, according to a 2005 report by Curtis. As an exhibit on the city's historical impact opened in Berlin last week, researchers from around the world gathered nearby to discuss how to manage the decaying site and stave off plans for development, including new parking lots and a hotel. The rescue effort has been stymied for years by changes in the archaeology leadership in Baghdad and bickering between Americans and Europeans. “It is very disappointing it has taken so long to agree on an assessment,” says Curtis, who visited the site in 2004. “Only after that is done can we move forward.” The U.S. government intends shortly to announce a $700,000 contract with the World Monuments Fund to begin work on the management plan.

    Archaeologists may learn more during an upcoming U.S.-sponsored visit to sites in central or northern Iraq, according to spokesperson Olson and archaeologist Diane Siebrandt, also of the State Department in Baghdad. Olson declined to discuss the trip, however, citing “operational considerations,” and Siebrandt would not provide details about any U.S. efforts to cope with the damage and looting resulting from the war.

    Stone, meanwhile, sees a silver lining in the havoc. The focus on satellite data may help archaeologists unable to work on the ground understand ancient Mesopotamian settlement patterns and architecture, she says, gaining fresh insight into how its inhabitants once lived.

  9. ARCHAEOLOGY

    On Iraq's Front Lines

    1. Andrew Lawler

    Abdel-Amir Hamdani, director of antiquities in the Nasiriyeh region of southern Iraq, spent 3 months in jail for opposing plans to build a dozen brick factories on top of an important archaeological site. Hamdani's tribulations reflect the precarious state of Iraq's archaeological heritage 5 years after the war began (see main text).

    First Abdel-Amir Hamdani was charged with theft and kidnapping. Then his home was searched. Finally, the director of antiquities in the Nasiriyeh region of southern Iraq was thrown into jail for 3 months. His crime? Opposing plans by unscrupulous developers intent on building a dozen brick factories on top of an important archaeological site. But Hamdani, who was ultimately cleared of all charges and released, says his harrowing ordeal was worth it because the developers eventually abandoned their plans. “The result was good,” he said during a recent visit to the United States. “If you gave me a choice between jail and brick factories, I would choose jail.”

    Hamdani's tribulations reflect the precarious state of the country's archaeological heritage 5 years after the war began (see main text). “This is what we have to do as archaeologists to protect Iraq's heritage,” says Donny George, former chair of the State Board of Antiquities and Heritage in Baghdad and now a professor at Stony Brook University in New York state.

    Setting his sights.

    Hamdani searches the Iraq marshes for ancient settlements.

    CREDIT: ABDEL-AMIR HAMDANI/SBA

    Shy, soft-spoken, and rail-thin, the 40-year-old Hamdani is an unlikely archaeological hero. But since the U.S. invasion began, he has tried to find ways to protect the vast region he oversees in south-central Iraq. Intensive looting began as soon as Saddam Hussein's forces retreated and the U.S. military rolled north to Baghdad in March 2003, he says. The region is littered with thousands of ancient settlements, which represent a treasure trove of salable goods to an impoverished population. Hamdani has worked with a succession of American and Italian military officers to ensure that archaeological sites were patrolled; he even traveled to the holy city of Najaf to explain the dire situation to Grand Ayatollah Ali al-Sistani, a powerful figure in mostly Shiite southern Iraq. Al-Sistani quickly issued a fatwa forbidding the pillaging of ancient sites. Hamdani is also currently surveying sites exposed in the past decade after Saddam drained the marshes of southern Iraq.

    Such work is complicated by continued fighting, however. The museum's offices were ransacked and the adjacent library burned in a May 2004 clash between militia and the Italian forces who replaced the Americans. “We lost everything,” recalls Hamdani. The Italians later renovated the museum, but this spring attacks destroyed vehicles and damaged the museum's façade and roof.

    Hamdani's biggest challenge was deflecting a 2005 proposal by the Nasiriyeh city council to build 12 brick factories just outside town, between the ancient Sumerian cities of Ur and Ubaid. The site of very early settlement dating to the 6th millennium B.C.E., Ubaid gives its name to an entire era known as the Ubaid period. Ur was a large city during the first florescence of urban areas in the 3rd millennium B.C.E., as well as the legendary home of Abraham. When Hamdani conducted a required survey, he discovered that the site was littered with ancient Sumerian material. “We need these factories,” he says, “but not on top of an archaeological site.” So, representing the Baghdad antiquities department, he denied permission for construction.

    In February 2006, Hamdani says that those supporting the site location struck back with a memo to a local judge alleging that he had stolen gasoline from departmental tanks, that he was involved with a kidnapping, and that his son was an antiquities smuggler. Police searched his home and found nothing suspicious, but that April Hamdani was jailed. He calls the accusations absurd, given that the department has no gasoline tanks in Nasiriyeh and that his son was 2 years old at the time. And he denies any involvement in kidnapping. George confirms the tale and says that Hamdani's success in putting looters in jail led to the reprisal. After officials in Baghdad intervened, Hamdani was cleared of the charges and released that June.

    The experience has not cowed Hamdani, who studied archaeology at Baghdad University. But he feels lucky to have escaped the ordeal with his life. “I could have been shot like so many others,” he says. “There is an underworld there like the Mafia. Sometimes you forget being an archaeologist, and you work as a policeman.”

  10. EPILEPSY

    When Death Strikes Without Warning

    1. Jennifer Couzin

    After years of neglect, a devastating effect of epilepsy, sudden death, is drawing new scrutiny.

    After years of neglect, a devastating effect of epilepsy, sudden death, is drawing new scrutiny

    CREDIT: K. SUTLIFFE/SCIENCE

    The call came on a Thursday, 21 February 2002, while Jeanne Donalty sat at her desk at work. Her son Chris, a 21-year-old senior at a Florida college, had stopped breathing. His girlfriend found him on his bed, surrounded by the books he'd been studying and a summer job application. Paramedics were unable to revive him, and just like that, Chris Donalty was gone.

    Chris Donalty had had epilepsy—he suffered his first seizure in school when he was 9 years old—but his mother at first saw no clear line connecting his death and the disease for which he was being treated. An autopsy found no visible cause of death, and it was shortly after that that Jeanne Donalty discovered a term she had never heard before: SUDEP.

    Sudden unexpected death in epilepsy, SUDEP was first written up in The Lancet in 1868 by a British physician; he described the phenomenon as “sudden death in a fit.” Neurologists today are familiar with SUDEP, which is thought to follow a seizure, and most specialists have lost patients in this way. “Four or five times a year, someone will not come to my clinic because they have a SUDEP death,” says Mark Richardson, a neurologist at King's College London. Most victims, like Chris Donalty, are in their 20s or 30s.

    SUDEP has been little studied and is rarely discussed in the medical and scientific communities. Families often learn of it only after a relative's death. In the United Kingdom, which is well ahead of the United States in tracking SUDEP, it's estimated that SUDEP strikes at least 500 people a year. It's thought to explain between 8% and 17% of deaths in people with epilepsy. Among those with frequent seizures, the number may be as high as 40%. This increased risk, recognized only recently, underscores that SUDEP is more likely to occur if seizures are more frequent or treatment is inadequate.

    Chris Donalty was in that high-risk group: Despite taking his medications as prescribed, he suffered seizures regularly for 2 years before his death. But he never told his parents—because, they now believe, he did not want to lose his driver's license. “I don't know of any other disease that can be fatal where patients aren't aware of” that risk, says his mother.

    Driven largely by grieving families, more doctors are discussing risk of SUDEP with patients, and research is picking up. A few studies are focusing on what happens to breathing and heart rhythm during seizures. In the U.K., researchers and advocates hope to set up a nationwide registry of SUDEP cases. The U.S. National Institutes of Health (NIH) will host several dozen specialists at its Bethesda, Maryland, campus this fall in a first-ever meeting on SUDEP. Still, the epilepsy community is divided on what to tell patients about the risk of sudden death—and exactly what should be done about it.

    Detective.

    Neurologist Lina Nashef dug into historical data in a quest to understand what causes sudden death in epilepsy.

    CREDIT: RINA PATEL/KING'S COLLEGE HOSPITAL NHS FOUNDATION TRUST

    In from the shadows

    Epilepsy, characterized by recurrent seizures caused by abnormal electrical activity in the brain, has long carried a stigma. Some say this may explain why physicians swept SUDEP under the rug: They didn't want to magnify existing fears, especially because no way to prevent it is known. “There was a real concern that the main message should be, ‘You can live a completely normal life with epilepsy,’” says Jane Hanna, who helped found the nonprofit Epilepsy Bereaved in Wantage, U.K., after her 27-year-old partner died of SUDEP shortly after he was diagnosed. Even textbooks on epilepsy omitted mention of SUDEP.

    But this discretion carried drawbacks, burying historical knowledge of SUDEP cases and slowing clinical investigation, says Lina Nashef, a neurologist at King's College Hospital in London. Until the early 20th century, many people with epilepsy lived in asylums or other institutions, where staff recognized that patients sometimes died during or after seizures. But the collective memory of these deaths faded as antiepilepsy drugs became widely available and patients began living independently. Most who die of SUDEP now do so at home, unobserved.

    Nashef began investigating SUDEP as a research project for a postgraduate degree in 1993, interviewing 26 families who had lost someone to sudden death. Although nearly all the deaths occurred without witnesses, Nashef was often told of signs, such as a bitten tongue, that occur after a seizure. The evidence in other cases was more circumstantial: One young man in his late teens, whose seizures were triggered by flickering light from television and computer screens, was found dead at a computer terminal in the library.

    Nashef identified a handful of characteristics that the SUDEP victims shared. All but three were battling regular seizures, though sometimes not more than two or three a year. And all had suffered from a particular type, called generalized tonic-clonic or, colloquially, grand mal seizure. Such seizures, the kind most people associate with epilepsy, are accompanied by a loss of consciousness and violent jerking motions and affect large swaths of the brain.

    What goes wrong?

    Digging deeper into SUDEP, Nashef and others have focused on two life-sustaining functions: respiration and heartbeat. Most physicians now believe that SUDEP stems from arrested breathing, called apnea, or heartbeat, called asystole.

    Buried history.

    Epilepsy's past is clouded by misunderstandings, but physicians and staff at institutions for epileptics, like Craig Colony in New York state, were aware of SUDEP deaths.

    CREDITS (TOP TO BOTTOM): NATIONAL LIBRARY OF MEDICINE; COURTESY OF THE MUSEUM OF DISABILITY HISTORY

    One broader question is whether apnea or asystole strike even during seizures that aren't fatal. Neurologists Maromi Nei and her mentor, Michael Sperling, both at Thomas Jefferson University in Philadelphia, provided an early clue in 2000 when they described electrocardiogram patterns from 43 people with epilepsy. Although none died of SUDEP, 17 of these patients had cardiac abnormalities during or right after seizures, including significant arrhythmias and, in one case, no heartbeat at all for 6 seconds.

    More recently, Nei and her colleagues investigated hospital records from 21 people who later died, apparently of SUDEP, and compared their heart rhythms with those from the original study, to see whether the SUDEP cohort had some signs of susceptibility. The biggest difference, they reported in 2004, was not the prevalence of arrhythmias but “a greater degree of heart rate change,” says Nei, with heart rate soaring by about 80 beats per minute during seizures that struck while they slept. Seizures tend to boost heart rate because they can provoke the autonomic nervous system, especially when the brain regions stimulated are those that trigger such “fight-or-flight” reactions. These data hinted that the phenomenon is exaggerated in those who later die of SUDEP.

    Now Nei is implanting devices under the left collarbone of 19 people with intractable epilepsy to gather data on their heart rhythm over a span of 14 months. Neurologist Paul Cooper of Hope Hospital near Manchester, U.K., is beginning a similar study with 200 people.

    Both studies follow a related and troubling report in 2004 from The Lancet. There, a group of British researchers described cardiac data from 377 seizures in 20 patients gathered over 2 years. Four of the 20 had perilous stretches of asystole and later had pacemakers permanently implanted to jump-start their hearts if needed.

    What might be behind this effect? Asystole isn't always dangerous, although it sounds alarming; it can happen even during some fainting spells. A normal heart starts beating again on its own—which leads clinicians to wonder whether the hearts of patients struck by SUDEP may harbor invisible defects. One possibility is that over time, repeated seizures can scar and damage the organ. Another is that a genetic defect may be causing both heart rhythm problems and epilepsy.

    Earlier this year, Nashef, King's College geneticist Neeti Hindocha, and their colleagues intrigued epilepsy specialists with a report on a family with a rare form of inherited epilepsy, including two members who died from SUDEP. The researchers, after gathering DNA from the living, found that all 10 family members who had epilepsy also carried a previously undescribed mutation in a gene called SCN1A, which was responsible for their disease. A so-called ion channel gene, SCN1A helps control electrical signaling between cells. Similar genes have been linked to epilepsy and sudden cardiac death. The authors postulated that the SUDEP deaths in this family were also caused by SCN1A, which could have disrupted heart rhythm or brainstem function in addition to triggering epilepsy. A group at Baylor College of Medicine in Houston, Texas, is now studying whether ion channel genes that can freeze the heart are also present in brain tissue.

    If cardiac defects like these are behind SUDEP, “it might be something preventable,” says Stephan Schuele, director of the Comprehensive Epilepsy Center at Northwestern Memorial Hospital in Chicago, Illinois. People with gene defects that cause sudden cardiac death, for example, receive pacemakers that can shock their hearts into beating again. Perhaps, doctors say, the same could be done for epilepsy—if they can determine who's at risk of SUDEP to begin with.

    Missing clues

    But Schuele, who's looking for other causes of SUDEP, notes that despite a few reports pointing to genetics, “there is no direct evidence” that asystole is killing people with epilepsy. Schuele wonders if the body's way of stopping seizures in the brain could also be disturbing vital brainstem function in some patients. These mechanisms, which are just starting to be explored and involve surges of certain neurotransmitters, may go overboard and cause chaos in the autonomic nervous system, which governs heart rate and respiration.

    The detective work is slow and arduous, in part because so few cases of SUDEP have come to light from epilepsy monitoring units in hospitals, where vital signs are recorded—perhaps, Schuele suggests, because health workers are loath to admit that a SUDEP death occurred on their watch. Last August, neurologists Philippe Ryvlin of the Hospices Civils de Lyon in France and Torbjörn Tomson of the Karolinska Hospital in Stockholm, Sweden, began surveying 180 hospitals in Europe for information on SUDEP deaths or “near-misses” that required resuscitation. Two months ago, they extended their search worldwide, collecting cases from as far away as India and the United States. They expect to conclude their collection and analysis in about a year.

    Just four cases have been published. The most detailed, in 1997 on a patient in Bristol, U.K., reported that that person's brain waves went flat before the pulse faded, perhaps causing a failure of the brain region that controls breathing. This suggests that heart failure could be a consequence, not a cause, of SUDEP. Still, “the mechanism of that brain-activated shutdown is very mysterious,” says Ryvlin. “Nobody knows what it could be.”

    There are clues that respiration is key. By monitoring it in hospitalized epilepsy patients, Nashef found that episodes of apnea were common during seizures. And a mouse strain used for decades to test epilepsy drugs has the disconcerting habit of dying from respiratory failure after a severe seizure. That was “generally considered a nuisance,” says Carl Faingold, a neuropharmacologist at Southern Illinois University in Springfield, until he and a handful of others realized the mice could be used to study SUDEP. At Boston College, biologist Thomas Seyfried found that putting the mice in an oxygen chamber during seizures prevented death in all of them.

    SUDEP victim.

    Chris Donalty, shown here with his father, Barry, died after a seizure at age 21 in his senior year of college.

    CREDIT: TRISHA DONALTY

    Faingold considered whether the neurotransmitter serotonin, which functions in the brain's respiratory network, might play a role. He gave the mice the antidepressant Prozac, a serotonin booster, and found that though their seizures remained the same, they were at least 90% less likely to die afterward.

    Faingold is disappointed that the mouse work has received little attention and no financial support from NIH—his SUDEP research is funded by an epilepsy advocacy group—and its relevance to humans has been questioned. Because no one can predict who will die of SUDEP or when, “if you don't have a way of investigating [SUDEP] in animals, you're very limited,” he says.

    Acknowledging the unmentionable

    Meanwhile, doctors face a more pressing question: what to tell their patients about SUDEP. “I admit, I am still trying to figure out the best way to do this,” says Elizabeth Donner, a pediatric neurologist at the Hospital for Sick Children in Toronto, Canada. She has grown more willing to share the information, but still, “sometimes we worry in telling people about this phenomenon … we could actually make their lives worse.” Already, one of the toughest aspects of epilepsy is its unpredictability. “When you add in a statement that some people die, and we don't know why and we can't predict it and we can't prevent it, that can be very scary.”

    U.K. national guidelines in 2004 recommended that physicians discuss SUDEP with everyone who has epilepsy. In reality, a survey of British neurologists published 2 years ago showed, “nobody told anybody anything,” says Cooper. Cooper and some other physicians believe that the 30% or so of patients whose epilepsy does not respond to medication—or those reluctant to take it—ought to be told of SUDEP, because they are at a higher risk than people whose epilepsy is controlled. The latter group, he believes, does not need to know about SUDEP.

    That perspective doesn't sit well with epilepsy advocates. “Anecdotally, we're aware of deaths every year in people with second or third seizures,” says Hanna of Epilepsy Bereaved. “It does worry me a bit if there's going to be some basic clinical practice that just cuts the line with people who seem to have the most serious epilepsy.”

    Jeanne Donalty still struggles with her family's ignorance of SUDEP while Chris was alive. “I'm not insensitive to how hard this is for a physician,” she says. If she had known of SUDEP then, “I would have been upset; … who wouldn't be? But I think you have the right to have all the knowledge about the disease that is out there, so that you can make your decisions based on that knowledge.” When it comes to sharing information on SUDEP, says Donalty, “to me, it's easy. You tell everybody.”

  11. PARTICLE PHYSICS

    Competing Teams Plot Two Different Paths to a New Particle Smasher

    1. Adrian Cho

    To make a new collider, physicists in Japan plan to push an existing machine to its limits. Others in Italy hope to cobble one together from old parts and a bright idea.

    To make a new collider, physicists in Japan plan to push an existing machine to its limits. Others in Italy hope to cobble one together from old parts and a bright idea

    Nearly departed?

    Parts of SLAC's PEP-II collider could be shipped to Italy to build a new collider for high-precision experiments, called SuperB.

    CREDIT: SLAC

    Many a teenager has dreamed of transforming a jalopy into a gleaming hot rod. Now, a team of physicists from the United States and Italy has proposed a project that sounds as unlikely. Using parts from an old particle smasher, they plan to build a new one that will crank out data 100 times faster than the original machine, consume less power, and possibly find hints of particles so massive that no collider could produce them directly—not even the new highest energy collider that will turn on in Europe this summer. But the project, dubbed SuperB, isn't the only dragster in this race: Physicists in Japan plan to upgrade their existing machine to do the same work.

    SuperB would be built at the University of Rome “Tor Vergata,” near Frascati National Laboratory in central Italy. But most of its parts would come from the PEP-II collider at the Stanford Linear Accelerator Center (SLAC) in Menlo Park, California, which was shut down in April—even though some say it still had plenty of science in it. SuperB team members hope SLAC and the U.S. Department of Energy (DOE) will donate PEP-II and the accompanying BaBar particle detector to the project as an in-kind contribution worth about $200 million. “Here's a contribution that doesn't cost anybody anything,” says David Hitlin, a team member from the California Institute of Technology (Caltech) in Pasadena. “Doesn't it make sense to leverage your assets?”

    SuperB would serve as a foil to the world's mightiest accelerator, the Large Hadron Collider (LHC) soon to power up at the European particle physics laboratory, CERN, near Geneva, Switzerland (Science, 23 March 2007, p. 1652). By smashing protons into protons, the LHC aims to blast massive new particles into existence. In contrast, SuperB would collide electrons and positrons at lower energies to produce a flood of familiar particles, and the details of their decays could reveal hints of new physics.

    The approach, called precision physics, has the potential to be “real cowboy physics,” says Thomas Browder of the University of Hawaii, Honolulu. Such a collider might spot rare decays that would rewrite the standard model of particle physics or even find hints of particles beyond the grasp of the LHC, Browder says.

    But SuperB has competition. Browder is one of about 400 physicists working with the KEKB collider and the Belle particle detector at the Japanese laboratory KEK in Tsukuba. They plan to upgrade that machine to create Super KEKB. “This was put into the official plan of KEK” in January, says Masanori Yamauchi, a particle physicist at KEK, “but the government has not given approval yet.”

    Heavy hints

    Because mass and energy are equivalent, physicists can pop a massive new particle into existence by colliding well-known ones at sufficiently high energy, as they aim to do at the LHC. But massive new particles can also cast shadows in the decays of far less massive ones, especially those made up of fundamental bits of matter called quarks.

    According to the standard model of particles, the matter around us consists of the up quarks and down quarks that make up protons and neutrons, electrons, and wispy electron neutrinos. This first “family” of particles is copied twice over, so there are heavier quarks of four more “flavors”: charm and strange, top and bottom.

    Consider the decay of a particle called a B meson, which contains a massive bottom quark and a lighter antiquark. Thanks to the uncertainties of quantum mechanics, the meson roils with other particles popping in and out of “virtual” existence within it, even ones more massive than the meson itself. So if there are new particles lurking over the horizon, they will flit about inside the meson and may reveal their nature by affecting the way the B meson decays.

    Physicists have used this approach to narrow in on new particles before. For example, in the 1980s, studies of B mesons, which are only five times as heavy as a proton, indicated that the then-hypothesized top quark was much heavier than previously thought, says Peter Krizan of the University of Ljubljana and the Jožef Stefan Institute in Slovenia. That inference proved correct when the top quark was found in 1995 and weighed in at 180 times the mass of a proton.

    Both the KEKB collider and SLAC's PEPII were built to do just this sort of work. Since 1999, the two “B factories” have pumped out scads of B mesons, and experimenters working with the BaBar detector at SLAC and the Belle detector at KEK have studied a slight asymmetry between B mesons and their antimatter counterparts, anti-B mesons. That discrepancy, known as charge-parity (CP) violation, had been previously seen only in lighter K mesons.

    BaBar and Belle proved that, to a precision of a few percent, the standard model's explanation of CP violation is on the mark (Science, 13 October 2006, p. 248). That was both a huge victory and a disappointment for physicists, as the theory contains far too little CP violation to explain why the universe contains gobs of matter but essentially no antimatter. “We all know that the standard model is a fantastic theory,” Krizan says, “but we also know that it's fantastically wrong.”

    Both the SuperB and KEKB teams now want a “super flavor factory” that will crank out far more B mesons, as well as mounds of particles called D mesons and tau leptons, heavier cousins of electrons. All that data would allow for even more precise tests of the standard model's CP-violation scheme. More important, says Hitlin, it might reveal rare decays that turn the theory on its head. “The point is not doing what you did before but better,” Hitlin says. “It's looking for these very rare decays.”

    Such studies would complement the LHC's direct search for new particles. If the LHC sees plenty of new particles, a super flavor factory would probe how they couple to quarks and other known particles. If the LHC sees nothing, then precision physics offers the best hope of sensing particles beyond its grasp. “These precision measurements are basically the only tool you have that shoots far beyond the mass reach of the LHC,” Krizan says.

    Huge currents, tiny beams

    The SuperB and KEK groups are taking different approaches to designing their machines. Similar to PEP-II, the KEKB collider comprises two circular accelerators that cross in the middle of the associated detector, one carrying electrons in one direction and the other carrying positrons in the other. “Our design is kind of brute force,” says Yamauchi. “We put more and more electrons and positrons into the rings.”

    KEK physicists would boost the current in the electron ring from 1.2 amps to 4.1 amps and in the lower energy positron ring from 1.6 amps to a sizzling 9.4 amps. They would squeeze the beams to half their current size and employ a new technique to reduce the tendency of the crossing beams to disrupt each other. The path to Super KEKB is “very, very predictable from our present machine,” says Katsunobu Oide, an accelerator physicist at KEK. By the time KEKB shuts down, probably in 2010, it will have created a billion B-anti-B pairs. Super KEKB would produce pairs at least 10 times faster and eventually make 50 billion of them.

    Instead of packing in more particles, SuperB would use greatly compressed beams, thereby increasing the rate at which electrons and positrons collide, which is called the luminosity. “We get 100 times smaller vertical size at the interaction point, and that means 100 times more luminosity with the same beam current,” says Pantaleo Raimondi, an accelerator physicist at Frascati who dreamed up the scheme. At the start, SuperB would crank out data five times as fast as Super KEKB's initial rate.

    SuperB would collide beams only 35 nanometers across. To make such tiny beams, researchers must very precisely arrange both the magnets that steer the beam around a ring and those that focus it, Raimondi says. The SuperB design borrows from work on “damping rings” being developed to compress the beams in the proposed International Linear Collider (ILC), a multibillion-dollar straight-shot collider that would study in detail new particles discovered at the LHC.

    Subtle signals.

    A B meson decays into a tau lepton and an antineutrino. The probability for the decay would differ from standard model predictions if there are new particles that could fill the role of the familiar W boson.

    To limit the cost of SuperB to roughly $500 million, researchers plan to reuse the PEP-II hardware from SLAC. In fact, physicists had proposed upgrading PEP-II where it stands as early as 2001. Those plans were squeezed out by tight budgets in DOE's particle physics program and by the U.S. community's desire to push to host ILC. Now that a PEP-II upgrade is “not in the cards,” the lab may be willing to part with the machine, says Steven Kahn, SLAC's director of particle physic and astrophysics. “We're not seeing any major hurdles to our saying yes to this,” he says. SLAC has asked the Italian National Institute for Nuclear Physics (INFN) to formally request the equipment, Kahn says.

    Pros and cons

    Each approach has both strengths and potential weaknesses. The Super KEKB design requires no conceptual leaps, but circulating nearly 10 amps of current presents its own challenges. The extent to which the beams disrupt each other increases with the number of particles in them, says John Seeman, an accelerator physicist at SLAC, so achieving the luminosity increase may be tricky. The high currents would also increase power consumption of the complex from 40 megawatts to 80 megawatts, raising yearly operating costs by tens of millions of dollars.

    In contrast, the SuperB collider would use only 20 megawatts, less than PEP-II did. But steering its tiny beams into each other may be tough, Oide says. “To collide such tiny beams is not trivial,” he says. “It's many orders of magnitude more difficult than producing a single nanometer-sized beam.” SuperB researchers will have to limit vibrations at the crossing point to just 3 nanometers, Oide says. However, if the tiny-beam scheme seems likely to work, then KEK researchers may simply adopt it, too.

    Politically, SuperB team members have a tougher row to hoe, as they are asking the Italian government for hundreds of millions of euros to build a new laboratory to house the collider. A subpanel of the European Committee for Future Accelerators is studying the plan. If both it and the CERN Strategy Group, which keeps the road map for European particle physics, give the plan high marks, then INFN will ask the Italian government for funding. Physicists hope to begin detailed design work as early as next year.

    In contrast, KEK researchers already have a lab and machine. KEK is negotiating for funding with Japan's Ministry of Education, Culture, Sports, Science, and Technology. Researchers hope to shut down KEKB in 2010 and spend 3 years building Super KEKB. At the least, they hope to use the money saved from KEKB's operating budget to fund $220 million in improvements. The full upgrade would cost much more, but Japanese researchers are reluctant to say how much.

    Given the financial demands of the LHC and other projects and tight funding all over, many say the community can likely afford only one super flavor factory. “In the end, the country that wants the machine the most and puts up most of the money will get it,” Seeman predicts. Will it be Italy or Japan? Physicists may know within a year.

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