News this Week

Science  16 Aug 2013:
Vol. 341, Issue 6147, pp. 698

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  1. Around the World

    1 - Beijing
    China to Share Nuclear-Monitoring Data
    2 - Luttelgeest, the Netherlands
    Return of the Wolf
    3 - Washington, D.C.
    U.S. Blocks Import of Beluga Whales
    4 - Okuma, Japan
    Government Takes Role in Fukushima Cleanup
    5 - Bicol region, Philippines
    Activists Destroy 'Golden Rice' Field Trial


    China to Share Nuclear-Monitoring Data

    Hours after North Korea announced its third nuclear test in February, seismic signals around the world confirmed a massive explosion—but the United States and its allies were unable to detect radioxenon emanating from the test site quickly enough to distinguish whether it was a plutonium bomb or a uranium bomb.

    Next time might be different: On 8 August, the Vienna-based Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) announced that China has agreed to begin sharing data from 10 stations on its territory. Seven stations register seismic waves and infrasound waves; three stations in Beijing, Lanzhou, and Guangzhou detect radionuclides. Data from the stations would be fed into the International Data Centre maintained by CTBTO. To date, 85% of CTBTO's 337 planned monitoring stations around the world are operational.

    The breakthrough came during a visit to Beijing last week by Lassina Zerbo, the new executive secretary of CTBTO's preparatory commission. China is one of eight CTBT signatories whose ratification would bring the treaty into force; other holdouts include the United States and North Korea. (So far, 159 countries have ratified the treaty.) CTBTO now must certify the Chinese stations.

    Luttelgeest, the Netherlands

    Return of the Wolf

    End of the road.

    The wolf found in the Netherlands was the first seen in the country in 140 years.


    The good news: A wolf apparently traveled more than 900 kilometers to find a new home in the Netherlands, a densely populated country where the species was last seen more than 140 years ago. The bad news: The animal was killed, probably by a car.

    The discovery of the roadside carcass on 4 July triggered a raft of DNA and other studies—first, to determine whether it was really a wolf, and then to trace its origins. On 7 August, researchers from three institutes announced that the animal, a healthy female that lived at least 18 months, didn't peel off from the nearest known wolf populations in Germany and western Poland but most likely wandered in all the way from the Carpathian Mountains or the Balkans. An autopsy revealed that it had died from a high-impact blow.

    The arrival has bolstered Dutch conservationists' hopes that wolves—which have recently been moving westward in neighboring Germany, close to the Dutch border—will soon make a spontaneous comeback in their country. The government has already ordered experts to write a wolf management plan, to be revealed in November.

    Washington, D.C.

    U.S. Blocks Import of Beluga Whales


    A U.S. agency rejected a request to import captive belugas.


    The U.S. National Marine Fisheries Service (NMFS) on 6 August denied a request from a consortium of U.S. marine parks and aquariums to import 18 beluga whales (Delphinapterus leucas) from Russia's Sea of Okhotsk, finding the move would violate marine mammal protection laws. The June 2012 request for the import permit divided marine mammal scientists and drew extensive opposition from animal rights groups.

    The Georgia Aquarium, which led the request, lamented the decision, saying that it would set back efforts to study the species and reduce opportunities for public education. But conservationists applauded.

    NMFS determined that the Georgia Aquarium's request fell short in three ways: The agency found that the imports would adversely affect the specific population of whales from which the belugas were captured; that approving the permit would likely lead to the seizure of additional marine mammals for display; and that past captures had not adhered to Marine Mammal Protection Act rules that only adult or juvenile animals be taken. The fate of the 18 captive belugas is unclear.

    Okuma, Japan

    Government Takes Role in Fukushima Cleanup

    The government of Japan will intervene in the management of the Fukushima nuclear power plant disaster, which so far has been left to Tokyo Electric Power Co. (TEPCO), the operator of the stricken reactors. Prime Minister Shinzo Abe ordered his administration to "provide multiple, speedy and sure solutions" after TEPCO recently admitted that water laden with cesium, strontium, and tritium is leaking into the Pacific Ocean. TEPCO's admission came nearly a year after marine scientists reported that persistently high levels of radionuclides in the ocean near the plant indicated that efforts to contain contaminated water were not working.

    The estimated 300 tons of radio active water flowing into the ocean each day will not have "a significant impact on the marine environment," says Jota Kanda, an oceanographer at the Tokyo University of Marine Science and Technology. But because strontium accumulates in bone, it "may become a greater concern in the seafood supply," says Ken Buesseler, a marine chemist at Woods Hole Oceanographic Institution in Massachusetts.

    Japanese officials proposed containing the tainted water by creating a barrier of frozen soil between the reactors and the sea. But ground freezing "has never been done on these scales of size and time," Buesseler says.

    Bicol region, Philippines

    Activists Destroy 'Golden Rice' Field Trial

    Mowed down.

    Uprooted and trampled plants at the vandalized golden rice field.


    Protestors from two anti-GMO groups, KMB and Sikwal-GMO, on 8 August vandalized a field of genetically modified (GM) "golden rice" in the Philippines, swarming over the field and uprooting stalks. The rice was just weeks away from being harvested, says plant biologist Ingo Potrykus, one of the researchers who originally created the rice strain.

    Golden rice is engineered to carry two foreign genes—one bacterial and another from maize—that together produce beta carotene, a precursor of vitamin A. Scientists hope distribution of the modified rice can make inroads against vitamin A deficiency, which can lead to blindness and makes people more susceptible to infectious diseases.

    The vandalized field was one of five involved in golden rice trials in the Philippines. Golden rice could be deemed safe and approved by the Philippine government as early as the end of this year, says Robert Zeigler, director general of the International Rice Research Institute. But further trials assessing whether the beta carotene in the rice is absorbed and converted into vitamin A in vitamin A-deficient people could take another 18 months.

  2. Random Sample

    Biological Art


    The winners of the 2013 Federation of American Societies for Experimental Biology (FASEB) BioArt competition each offer a sneak peek into science on the move, using a range of imaging techniques (magnetic resonance imaging, electron microscopy, fluorescence microscopy, and so on). The 10 image winners (plus two video winners), announced on 8 August, captured snapshots from a variety of subjects, including magnetic resonance images that map water motion in the brain tissues of a living monkey, a scanning electron micrograph of the transport of micronsized silica beads (standing in for targeted drug delivery) to human fibroblast cells, and a tiny embryonic little skate sitting on its yolk sac (pictured; the red strands are external gills).


    Following record numbers of bottlenose dolphin deaths in July—which saw 89 stranded bottlenose dolphins, seven times the average for the month—the U.S. National Oceanic and Atmospheric Administration has declared an Unusual Mortality Event for the marine mammals in the mid-Atlantic region from Virginia to New York. Scientists are searching for answers; the dolphins were mostly stranded dead and decomposed, but at least one has tested positive for morbillivirus, the cause of a die-off that killed more than 700 dolphins along the U.S. Atlantic Coast in 1987.

    Play Find the Fungus


    There's a fungus among … the ash trees. The "ash dieback fungus" (Chalara fraxinea) was first identified in Poland in 1992 and quickly spread across Europe. In the United Kingdom, it first appeared in 2012; now, U.K. scientists worry that the fungus is poised to spread to the rest of the country.

    Hoping to slow its spread, the U.K. government is using social media—mobile phone apps and open-access crowdsourcing hubs—to help study the emerging pathogen. Now, scientists are adding a new strategy: Facebook gaming.

    "I saw an opportunity to take advantage of a new way of working"—using online games to answer questions about variations in the genomes of both the fungus and the ash trees—says Dan MacLean, a genomicist at the Sainsbury Laboratory in Norwich, U.K. "We need to find the genetic variants that are associated with resistance in the ash or with lethality in the fungus." Genomes are pieced together from small overlapping DNA sequences. Once there's a reference genome established for the species, scientists then try to match sequences of DNA to it from samples, hunting for differences between the strains. "The whole puzzle is a pattern-recognition puzzle," MacLean says.

    Enter "Fraxinus," a Facebook game that debuted 12 August (after beta-testing by middle schoolers, pictured). Fraxinus takes advantage of the human eye's natural pattern-recognition ability to detect differences in sequences that computers might miss. Players match nucleotide sequences, represented by colorful leaf shapes, to a reference genome to create the best possible alignment. The game also has an element of competition: You get more points for beating someone else's score on a "puzzle." "That's useful scientifically," MacLean says—it means multiple pairs of eyes on the same data point, refining the data.

  3. New Team, Old Hands

    1. David Malakoff,
    2. Jeffrey Mervis

    President Obama is hoping that experienced managers will help him overcome Washington gridlock and leave a legacy of accomplishments in science.


    Out with the visionary laureates, in with the pragmatic wonks.

    That's one intriguing theme emerging from President Barack Obama's recent picks to lead key U.S. science agencies in his second term. That first group, now largely gone, included a slew of Washington outsiders, among them Nobel Prize winners and high-profile academics. They were brought in to shape the administration's research agenda at a time when the White House welcomed fresh ideas and all things seemed possible.

    Now, with Washington paralyzed by political gridlock and expectations diminished in a lame-duck presidency, the new corps of leaders possesses a bit less pizzazz but arguably more managerial experience. And many on the new team share a common bond: In the 1990s, they held sometimes obscure but important science policy jobs under President Bill Clinton. Those jobs served as priceless preparation for navigating Washington's convoluted culture.

    Researchers who study presidential hiring aren't surprised by the shift. "First-term appointments tend to be more symbolic and ideological, while second term appointments tend to be more technocratic and managerial," says political scientist David Lewis of Vanderbilt University in Nashville. Still, in Obama's case, the contrast can be striking. Here's a look at three new arrivals, and some key posts that are still vacant.

    Secretary of Energy: Ernest Moniz for Steven Chu

    Chu, a Nobel laureate and director of the Lawrence Berkeley National Laboratory in California, brought scientific star power to the White House's effort to remake the Department of Energy (DOE) into a hotbed of clean power innovation. By the end of his tenure, however, the sparkle had dimmed as a result of repeated clashes with Congress over DOE financing of green energy companies, chronic complaints about cost overruns in the department's nuclear weapons programs, and Chu's often uneasy public persona, which some in Washington interpreted as arrogance.

    In contrast, Moniz, a career academic at the Massachusetts Institute of Technology in Cambridge and longtime government adviser, brings a friendly-butcher-at-the-corner-store vibe to the job. That style has played to rave reviews in Congress, with the Senate rapidly and unanimously confirming his appointment in May.

    Moniz is at ease in government, observers say. He served 2 years as a senior official in Clinton's science policy shop before moving to a senior position at DOE. Since then, he's been a regular on government and White House advisory panels. "Not many scientists know Washington the way Ernie does," says David Garman, a former senior DOE official.

    That familiarity may explain Moniz's move to make DOE management reform an initial centerpiece of his tenure. In addition to shaking up DOE's leadership structure, he's discussing ways to streamline its sprawling network of 17 laboratories (Science, 12 July, p. 119) and $5 billion Office of Science.

    Director, National Science Foundation (NSF): France Córdova for Subra Suresh

    Congress spared NSF from the brunt of this year's sequester, and President Obama has asked for a 10.5% increase in 2014. But despite NSF's favored budget status, Córdova will still need the management skills that she developed over the past decade as president of Purdue University and the University of California, Riverside, as well as her knowledge of Washington acquired during 3 years as chief scientist to NASA Administrator Dan Goldin in the first Clinton administration.

    Her biggest challenge after being confirmed will be to sustain NSF's bread-and-butter disciplinary research programs without ignoring new opportunities. Her predecessor, Subra Suresh, created the template OneNSF to launch programs that promoted high-risk collaborative research, entrepreneurship, international partnerships, and more family-friendly workplace policies. NSF's 2014 budget request would boost them significantly. But the chair of the Senate Appropriations Committee, Senator Barbara Mikulski (D–MD), has told NSF to tap OneNSF money if Congress, as expected, cannot match the president's overall request for NSF's six research directorates.

    Córdova will also need a strategy to advance the White House's plan to reorganize STEM (science, technology, engineering, and mathematics) education. Although Congress has resisted the president's request to make NSF one of three lead agencies and boost overall funding for STEM education, the White House is unlikely to drop the idea. And the perennial challenge of finding room in a tight budget for expensive new scientific infrastructure is also likely to resurface. The National Ecological Observatory Network is still rapidly expanding, and this year NSF got the green light to request money to start building the Large Synoptic Survey Telescope, a wide-angle sky-mapping instrument in Hawaii.

    Administrator, National Oceanic and Atmospheric Administration (NOAA): Kathryn Sullivan for Jane Lubchenco

    Twenty years ago, after becoming the first American woman to walk in space, Sullivan signed up for a more prosaic job at the National Oceanic and Atmospheric Administration (NOAA). As the agency's chief scientist, "she was a troubleshooter," helping sort out troubled projects, recalls oceanographer James Baker, the NOAA administrator at the time.

    Now, as Obama's nominee to replace marine scientist Jane Lubchenco at NOAA's helm, Sullivan will be responsible for completing some of those same projects. Near the top of her list is a $12 billion satellite program, the Joint Polar Satellite System (JPSS), which has struggled through 20 years of cost overruns and reorganizations, threatening to wreck NOAA's $5 billion budget along the way. Sullivan, a geologist, worked on an early version of JPSS as chief scientist and helped implement major reforms since returning to NOAA as a senior leader in 2011. So "she understands the problems that come with big technology," Baker says.

    Baker also expects Sullivan's experience running museum and science education programs in Ohio—which occupied her between stints at NOAA—to come in handy as she promotes NOAA's work in everything from building climate models to regulating fisheries. "She's used to explaining why a program is important," he says.

    Still to come …

    The White House has yet to announce its picks for a slew of other important science posts. At DOE, open posts include the head of the Office of Science; a new undersecretary position overseeing science and energy programs; and the head of the Advanced Research Projects Agency–Energy, which promotes the commercialization of new technologies. The top job at the U.S. Geological Survey (USGS) is also open, but former director Charles "Chip" Groat says that finding a willing candidate could be tough. As USGS's budgets have stagnated, he says, "it's become a job of managing decline."

  4. The Women of the Cosmos Club

    1. Jeffrey Mervis

    It's not the food that brings female scientists to Washington's Cosmos Club each month.

    Founded in 1878 as a bastion of the powerful in Washington, the Cosmos Club didn't allow women to be members until 1988. But a few years later, a group of local women decided to welcome their newly arrived peers in the Clinton administration with monthly dinners there. As the Obama administration seeks experienced managers (see main story, p. 706), some of the then-newcomers are making a return appearance.

    Clinton had appointed a large number of women to several federal research agencies. Many of them "had no social or professional network here," says Florence Haseltine, a scientist emeritus at the National Institutes of Health in Bethesda, Maryland, and founder of the Society for Women's Health Research, who kick-started the meals in 1993. "Dinners were a chance for them to exchange information on how the system works."

    The meals triggered discussions on topics that never came up during meeting-filled workdays, says physicist Martha Krebs, who was part of that influx as director of the Office of Science at the Department of Energy (DOE). "At dinner we could talk about how to get things done—the career staff at another agency that your staff needed to deal with, or how to handle interactions with Congress." A glass of wine and some good food also helped the women form bonds that lasted far beyond their tenures in Washington, adds Krebs, who left DOE in 2001 to return to academia and who is now head of research at the University of California, Davis, Energy Institute.

    The dinners were once so popular that they almost outgrew the venue. "I can remember a few times we had more than 30 women, and the club liked me to keep it to 12," says Haseltine, who also serves as the group's unofficial secretary. The irony of dining at the Cosmos Club was part of its appeal, Krebs admits. "It was a little bit of 'in your face,' I suppose. And because we could."

    Two of the "new faces" in the Obama administration—France Córdova and Kathryn Sullivan—were regulars at those dinners, as was Catherine Woteki, now undersecretary for research at the U.S. Department of Agriculture. Also back in town is the only man who ever attended the dinners: newly confirmed Energy Secretary Ernest Moniz, another Clinton administration veteran. "It was a big, extended group," Córdova recalls fondly. "It was a very good time to be a woman scientist in Washington."

    But times change. "It's a different environment now," Córdova says. "There are a lot of women in scientific posts in Washington now, and I'm not sure that [the dinner group] is needed now. I don't think you should do things just to do them."

    Haseltine still has a standing reservation at the Cosmos Club for the third Tuesday of the month. Sometimes the only attendees are she and co-founder Mary Clutter, the longtime head of biology at the National Science Foundation who retired in 2005. But she plans to keep the welcome mat out for both newcomers and returnees. "You can see what you're eating, it's got free parking, and the food is better than it used to be," she says.

  5. Solar System Exploration

    Pluto, the Last Planetary First

    1. Richard A. Kerr

    The New Horizons spacecraft will finally reveal much of Pluto's true nature; scientists are feverishly speculating about what they'll find.

    On target.

    New Horizons will pass through the Pluto system in 2015, piercing two shadows for a look back sunward, and then will visit a Kuiper belt object or two (candidates in green).


    LAUREL, MARYLAND—The next planetary first will be our last. After traveling for 10 years and crossing more than 5 billion kilometers, NASA's New Horizons spacecraft will flash by Pluto in a matter of hours, and an age of exploration will be over. Never again will a fuzzy ball of light in astronomers' telescopes crystallize into a new, exquisitely detailed world before everyone's eyes. Pluto aficionados gathered* here last month to anticipate the 14 July 2015 encounter, which Alan Stern, of the Southwest Research Institute (SwRI) in Boulder, Colorado, and principal investigator of the New Horizons mission, called "an epochal milestone in the exploration of the solar system."

    It will be epochal because our world knows so little about that world. An ice dwarf planet, Pluto is the archetype of billions of icy bodies that roam the outer solar system, left over from the formation of the "real" planets. The Earth-orbiting Hubble Space Telescope shows it as no more than a smudged disk with an outsized moon, Charon, and four tiny moonlets orbiting the pair. What will flying through that system just 12,500 kilometers above Pluto reveal? Inner fires might still be fueling icy volcanoes, despite surface temperatures just 40° above absolute zero. Or Pluto might disappoint with a surface that has been geologically dead for eons. Or, tragically, a stray fleck of ice might blast New Horizons, ending the mission, as it speeds past Pluto at 49,000 kilometers per hour?

    "We can expect the unexpected," said planetary geologist Paul Schenk of the Lunar and Planetary Institute in Houston, Texas, at the meeting. "We are going to be captivated; we are going to be befuddled."

    Two faces of Pluto

    Two Possible Analogs for Pluto

    Callisto: Dead. Pocked by impact craters, Callisto lacks internal heat to drive geologic resurfacing.


    Triton: Alive. Resurfaced by icy lavas and churning of its crust, Triton has few impact craters remaining.


    Speakers bold enough to predict what New Horizons will find on Pluto faced a stark choice: Does Pluto hold geological wonders like those the Voyager 2 probe found in 1989 on Neptune's youthful moon Triton, a close relation of Pluto's? Or will Pluto present an eons-old, crater-pocked face like the one that Voyagers 1 and 2 found on Jupiter's big moon Callisto?

    It all depends on how much heat has been generated and retained inside Pluto since it formed. Triton has much in common with Pluto. It is another protoplanetary leftover of similar size and composition to Pluto; Neptune just happened to capture Triton into orbit as a moon. Triton has plenty of internal heat, to judge by images from Voyager 2's flyby, perhaps fueled by lingering stores of heatgenerating radioactive elements in its rocky core. Only an internal heat source could have driven icy lavas to the surface over the past few tens of millions of years to form vast smooth plains, which have smothered most impact craters in their path. And heat must have driven the slow churning of solid crustal ice that produced Triton's mottled "cantaloupe" terrains and erased craters as well.

    Indeed, Triton appears to be so geologically vigorous that most researchers believe that it probably has an internal ocean of still-liquid water deep beneath an icy outer shell. And where there is liquid water, there could be life.

    Callisto, one of the four large moons of Jupiter, is another matter entirely. Not that different in size or composition from Triton, it was never heated much. Scientists are not sure why, but there was not even enough heating to completely separate its rock from its ice to form a rocky core, let alone to reshape its surface. The Voyager spacecraft found a surface with almost every square kilometer scarred by impacts of all sizes, accumulated over billions of years. That doesn't leave geologists with a lot to ponder. And no one is imagining an inner ocean for Callisto.

    At the meeting, planetary geologist John Spencer of SwRI stuck his neck out and said he would be "very surprised" if Pluto were heavily cratered. Because Pluto resembles Triton in size and composition, it, too, could have an internal heat source powerful enough to drive geologic activity, he concluded. "It could be just as wonderful and exotic as Triton's surface," he said.

    Planetary geophysicist Francis Nimmo of the University of California, Santa Cruz, predicts disappointment. "I would not be surprised by a totally dead surface" on Pluto, he says. He now thinks the analogy with Triton is flawed. Rather than being heated solely by a stockpile of radioactive elements, he says, Triton is probably also warmed by the rhythmic squeezing of Neptune's gravity. Pluto, with no nearby giant planet, receives no such tidal massaging, Nimmo notes.

    The red shift

    Even if Pluto is geologically dead, its wisp of an atmosphere most certainly is not. Pluto "is definitely changing color, getting redder," said Marc Buie of SwRI, who has been gleaning what he can from telescopic images of Pluto for more than 30 years. And the color change, which Buie found to occur between 2000 and 2002, almost certainly involves plutonian meteorology of a sort you won't see on The Weather Channel.

    On Pluto, the atmosphere—with 1/100,000 the pressure of Earth's—is actually Pluto's crustal "rock" sublimated into a near vacuum. The surface is frozen molecular nitrogen—the stuff we breathe—with traces of methane and carbon monoxide. In recent years, Pluto's northern hemisphere has been gradually turning toward the sun, and the rising warmth of summer may have driven off bright methane or nitrogen frosts deposited during the winter. That would expose underlying nitrogen ice, which is dirtied by dark, reddish gunk that radiation forms from the methane.

    New Horizons' cameras, which team with composition-analyzing spectrometers, will reveal details of the distribution of frosts that could help explain the recent reddening. Changing patterns of frosts might also account for the only two surface markings that Buie is sure he can see: an equatorial blotch of material as dark as soot and an adjacent blotch as bright as pure snow.

    The cameras may also be able to peer inside Pluto, in a manner of speaking. Precisely gauging the shape of Pluto's gravity field would be the best way to probe the nature of its interior—whether it has a rocky core, for example. New Horizons won't be passing close enough for that, but the cameras will measure the size and shape of Pluto to within a few hundred meters. A precise size will nail down its density, a key indicator of Pluto's overall composition.

    A precise shape could also fill in much of Pluto's history of heating and cooling. An oblate Pluto, flattened from pole to pole, could signal that it has retained enough heat to keep water liquid inside it, forming an inner ocean that makes Pluto flexible enough to deform under its own rotation. Or a more extreme oblateness could point to an early ocean that froze top to bottom while Pluto was spinning more rapidly, leaving its mark on the now-rigid dwarf planet.

    New Horizon team members are looking forward to measuring not just Pluto's shape, but also its tail. In its origin among the frozen relics of planet formation and its rock-and-ice composition, Pluto is essentially a very big comet. The solar wind of magnetic field and charged particles—mostly protons—streaming from the sun is blowing away about 140 kilograms of Pluto's atmospheric nitrogen each second, presumably into a cometlike tail. But "we absolutely have no idea of what this is going to look like," says space physicist Frances Bagenal of the University of Colorado, Boulder. "That's what's exciting about Pluto."

    Out at Pluto—30 times farther from the sun than Earth—the solar wind's enveloping magnetic field is so weak, Bagenal says, that charged nitrogen is far freer to roam. That puts Pluto in a different regime of space physics than ever seen at any comet, a realm two of New Horizons' instruments will explore. "It's an interesting way of tweaking the knobs of physics," she says, impossible to do in any lab.

    The danger of dust

    A millimeter-size dust speck of ice blasted off a moon of Pluto by an impact could end this scientific harvest. But mission planners are optimistic that the craft will survive the encounter with Pluto.

    Astronomers using the Hubble Space Telescope failed to turn up any threatening dust, but they would miss rare but lethal larger particles. Then calculations showed that Charon would quickly sweep up any particles straying into its orbit, so planners chose to send the craft through the Pluto system at Charon's orbit. Project scientist Hal Weaver of the Applied Physics Laboratory here told the meeting that the team now has "a high degree of confidence we'll be safe." He put a number to their confidence: less than 0.3% chance of loss of the mission.

    Assuming it survives its trip by Pluto, New Horizons will pass into the heart of the Kuiper belt, the home of many thousands of leftover objects like Pluto and smaller. If funding is renewed, the probe will take distant looks at many of them in the next decade. The team has already found 31 candidates perhaps close enough to the current trajectory that small thruster tweaks would bring New Horizons in for a close encounter with one or two of them.

    All in all, the last planetary first is shaping up nicely for Buie. When he picked the planet for his 1984 dissertation, he says, "I knew there was a pretty good chance I'd get a chance to peek in the back of the textbook and see the answers." That chance is coming up.

    • * The Pluto System on the Eve of Exploration by New Horizons, 22–26 July, at the Applied Physics Laboratory.

  6. Astronomy

    The Crab That Roared

    1. Yudhijit Bhattacharje

    The Crab nebula was famous for its rock-steady output of radiation. So when it began spewing gamma rays, at first researchers couldn't believe their instruments.

    Flare? Where?

    AGILE PI Tavani in photo composite with the unexpectedly assertive Crab.


    On an October morning in 2007, Marco Tavani took a train from Rome to Bologna to attend a meeting of the scientific team behind AGILE, a gamma ray telescope launched earlier that year by the Italian Space Agency. A researcher at Italy's National Institute for Astrophysics, Tavani had led the AGILE mission since it was conceived in 1997. Now that the observatory was finally in orbit, he and his colleagues were keen to start doing real science. First, however, they had to spend a few months confirming that AGILE was working as planned.

    As the train sped toward Bologna, Tavani switched on his laptop and got to work. A trim 57-year-old with silver hair and bushy eyebrows, Tavani has a ready laugh, but his equine face is engraved with deep frown lines. He was frowning as he stared at the slides he'd prepared for the meeting. The irritant was a map of the sky based on observations taken by AGILE in the last week of September, showing three bright gamma ray sources. Each is a rapidly spinning neutron star known as a pulsar: the Vela pulsar, a thousand light-years from Earth; the Geminga, some 500 light-years away; and the Crab, which spins at the center of the iconic Crab nebula, about 6000 light-years away.

    For decades, the three pulsars had emitted radiation so steadily that astronomers had come to rely on them as cosmic standards to calibrate their instruments—AGILE included. Geminga, being closer, normally shines brighter than the Crab. But in the AGILE map, the Crab blazed brighter and larger than Geminga. The anomaly raised the troubling prospect of a flaw in the telescope's detectors. Tavani wanted to wish it away.

    At the meeting in Bologna, attended by some two dozen researchers, Tavani delivered a technical talk on the satellite. Then he showed the audience the problematic slide. Several scientists expressed surprise. "This is very strange," said Marco Feroci, an astrophysicist at the Institute of Space Astrophysics and Cosmic Physics in Rome. "I have never seen anything like this before." But Tavani had more pressing problems to attend to. "For the moment, we put this week of observations in our drawer," he told the group. "And we do not talk about this to anybody."

    Tavani had passed up—for the moment— a chance to make a textbook-changing discovery about one of the most familiar objects in the heavens.


    Normally (top) Geminga far outshines the Crab in gamm a rays. But in 2010 (bottom), the Crab blazed forth.


    The Crab burst into human awareness in the year 1054, when astrologers in China reported seeing in the constellation Taurus a brilliant star that appeared out of nowhere and then faded away over several months. Centuries later, astronomers recognized the sighting as a massive stellar explosion, a supernova. The blast spread a bright, shiny blob of gas, or nebula, some 11 light-years across space, and in 1968, radio astronomers detected a pulsar at its center.

    That pulsar—which sets the entire nebula aglow—formed when the massive star that exploded into the 1054 supernova collapsed into a dense neutron star barely 20 kilometers across, spinning fast and powerfully magnetized. Those magnetic fields cause jets of particles accelerated to nearly the speed of light to shoot out from the star's magnetic poles, generating powerful beams of radiation across different energy bands that sweep Earth 30 times a second. Telescopes see the pulsar as a strobe light flashing with the unwavering precision of a cosmic metronome.

    Astrophysicists prize the Crab because it is the only nebula they can trace to its originating event, allowing them to figure out and confirm the physics of how it developed over time. Tavani saw its image in one of his first astronomy textbooks. Later he studied the Crab pulsar along with other neutron stars while working on his doctorate in theoretical astrophysics at Columbia University. In the 1990s, as a postdoctoral researcher, Tavani returned to the Crab nebula yet again in work aimed at understanding how the powerful winds of charged particles gusting from near the pulsar interact with the surrounding gas.

    In 1997, he moved back to his native Italy to begin working at the Institute of Space Astrophysics and Cosmic Physics in Milan. The Italian Space Agency had just put out a call for small missions, and Tavani and colleagues immediately started drafting a proposal for an observatory with a gamma ray imager and an x-ray detector on board.

    When AGILE was launched, in April 2007, the Crab nebula wasn't on Tavani's list of targets to study. It was too familiar and "boring," Tavani says—far less exciting than the exotic new gamma and x-ray sources he expected AGILE to discover.

    A year after the Bologna meeting, Carlotta Pittori, a researcher in Tavani's group, met with him to discuss her project: a catalog of the gamma ray sources that AGILE had observed in its first year. There were about four dozen of them. For each, Pittori had calculated the average gamma ray emission observed between July 2007 and June 2008. Scanning the numbers, Tavani's eyes homed in on the value for the Crab. "This cannot be so high," he remarked, noting that Pittori's number was 30% higher than readings NASA's Compton Gamma Ray Observatory had recorded in the 1990s. "See? It's not possible."

    The suspect value stemmed from data collected during the anomalous week in September 2007. The pulsar's recorded emissions then had been high enough to skew the average for the entire year. Tavani suggested that the gamma ray detector had temporarily malfunctioned, but Pittori was skeptical. "I would like to publish this table as is, without eliminating anything, with a note saying that this point is under investigation," she said.

    "No," Tavani replied. "We have to cut that week out." Scientists would normally frown on such an omission, but Tavani deemed it appropriate for data from a newly launched satellite still in its early phase of observation.

    The revised data set brought the emission value back in line with what astronomers were accustomed to seeing from the Crab. Tavani was satisfied. In a concession to Pittori, the paper on the catalog included a sentence stating that the average emission from the Crab had been found to be higher than usual when the researchers merged all the observations from 2007.

    The cryptic note went unnoticed when the paper appeared online in Astronomy & Astrophysics in September 2009. So did a figure that the authors later realized they had included by mistake. It was an image showing the Crab outshining Geminga—the same slide Tavani had shown his colleagues at the October 2007 meeting in Rome.

    In October 2009, Tavani was wracked with anxiety. He'd just got word that AGILE's reaction wheel—the device that helps point a satellite—had failed. Engineers at the Italian Space Agency had tried to restart it, but in vain.

    To salvage the mission, Tavani and his colleagues put AGILE into a spin. Every 7 minutes, it made a full rotation, its wide field of view sweeping out a circular band of the sky. The maneuver converted AGILE from a point-and-shoot imager to a sky survey, and by early 2010 the mission was back on track.

    To follow the latest observations, the researchers created a website onto which a fresh map of the gamma ray sky, as seen by AGILE, was uploaded every few hours. Tavani got in the habit of accessing it on his iPhone morning, noon, and night.

    Shortly before midnight on 20 September 2010, Tavani clicked on the link one last time before going to bed. On the map he saw a bright, yellow spot, right in the position of the Crab nebula. "Who knows what this is?" he said excitedly to his wife, showing her the screen. The Crab was at it again.

    The next morning, Tavani hurried to his office at the institute, where a 2-day conference for AGILE team members was about to begin. Before the morning session, he stopped by the office of his graduate student, Edoardo Striani, who was responsible for conducting fast analyses on AGILE data, and asked Striani to take a look at the Crab.

    Striani carried his laptop into the conference and settled down in a corner. His attention drifted in and out of the presentations. Analyzing the satellite's observations—downloaded every hour and a half by a receiver in Kenya, then relayed to the AGILE data center—he checked whether the emission from the Crab had been changing over the past few days.

    By the afternoon, Striani had confirmed that the emission had been rising. He and Tavani were witnessing a flare. "It immediately occurred to me that we had seen this in 2007," Tavani says. "At that moment, I knew the phenomenon was real."

    By the next morning, the Crab's emission had started to go back down, although it was still more than twice as high as normal. After the meeting's morning presentations, Tavani and Striani worked straight through the lunch break, plotting the pulsar's emission. Tavani was scheduled to give a "surprise talk" after lunch. He had planned to discuss a different gamma ray source, but now he had something meatier to present. "We have this phenomenon again," he announced, flashing his freshly made slides. "What do we do now?"

    Any postprandial lethargy in the room evaporated instantly. Pittori was jubilant. "Do you remember the note we put in the catalog?" she asked, grinning. It was the day before her birthday.

    A few hours later, the researchers put out an astronomical telegram announcing the flare to the broader community. The following day, researchers with NASA's Fermi gamma ray observatory reported that they had seen evidence of the flare in their archived data from the same dates. The teams described the flares in papers in Science a few months later (11 February 2011, pp. 736 and 739).

    Since 2010, AGILE and Fermi have both seen more flares in the Crab—one or two a year, each lasting a few days. In January, the American Astronomical Society awarded Tavani and the AGILE team its Bruno Rossi Prize "for a significant contribution to High Energy Astrophysics" for the discovery.

    What's causing the flares is still a mystery. The data show that the pulsar doesn't emit more energy than usual during the flaring episodes and that it gets brighter only in the gamma ray band of the electromagnetic spectrum, not at optical wavelengths. Tavani and others speculate that the wind of charged particles emanating from near the pulsar could be slamming into the surrounding plasma in a way that destabilizes regions of it. These plasma instabilities could be causing a runaway acceleration of particles that produces the spike in high-energy gamma radiation seen during a flare.

    But this explanation and others are still preliminary, says Bruno Coppi, a physicist at the Massachusetts Institute of Technology in Cambridge. "I think it would be unfair to call them theories," he says. Perhaps the solution is lurking in data that's already been collected, waiting to be recognized as such by a receptive mind.

  7. Infographic: Pesticide Planet

    A global look at the uses, benefits, and drawbacks of pesticides.

    In a world of humanmade chemicals, pesticides are second only to fertilizer in the amount applied and the extent of use. They are effective tools for protecting crops, fighting disease-cusing insects, and dealing with nuisance animals such as rodents, fleas, and ticks. But herbicides, insecticides, and their kin can harm the environment and are dangerous to workers if improperly used.

    Click the image for a larger version.


    [CREDIT: G. Grullón/Science; SOURCES (top to bottom): FAO Statistical Yearbook 2013; Phillips McDougall LTD; EPA Pesticides Industry Sales and Usage 2006 and 2007 Market Estimates; Rothhamsted Research; Malaria Journal 11 (28 March 2012); EPA Pesticides Industry Sales and Usage 2006 and 2007 Market Estimates, February 2011; USDA, Economic Research Service, National Agricultural Statistics Service; International Journal of Occupational and Environmental Health 8, 3 (Jul–Sep 2002); PNAS 110, 27 (2 July 2013); Science 336, 6079 (20 April 2012)]

  8. A Lethal Dose of RNA

    1. Kai Kupferschmidt

    A new generation of genetically modified crops will kill insects by silencing their genes.

    Corn consumers.

    Adult western corn rootworms. RNAi can kill their larvae, which feed on roots.


    When Andrew Fire and Craig Mello won a Nobel Prize in 2006 for a revolutionary technique to silence genes, there were high hopes that the discovery would lead to new treatments for disease. RNA interference (RNAi) might help tackle a wide variety of ailments, such as virus infections, cancer, and cardiovascular disease, the Nobel committee noted. Seven years on, the technology is almost ready to be applied—but rather than healing humans, it will kill insects.

    Scientists are using RNAi to build a new generation of crops that can fend off pests by making them express small bits of RNA, carefully chosen to match, and silence, crucial genes in the target insects. "It's the next big thing" in crop protection, says Andreas Vilcinskas, an entomologist at the University of Giessen in Germany. "Symposia on this are standing room only," says William Moar, a researcher at Monsanto in St. Louis, Missouri.

    The idea to equip plants with built-in pesticides is nothing new. Bt corn, on the market since 1996, produces the protein Cry, derived from a bacterium called Bacillus thuringiensis, which is toxic to moth larvae like the European corn borer. It may harm benign insects as well, and like most genetically modified (GM) organisms, it's controversial, yet Bt corn has taken the market by storm, leading to a drop in pesticide use. RNAi would take the concept to a new level by targeting harmful insects with surgical precision—although critics have suggested that the RNA molecules could also harm humans.

    Major seed companies are betting heavily on the technology. Last year, Syngenta bought Belgian RNAi pioneer Devgen for $522 million and Monsanto paid $29.2 million for the exclusive rights to intellectual property on RNAi technology from Alnylam Pharmaceuticals. "There is a race to get this to the field," Vilcinskas says.

    Targeted for destruction


    RNAi technology exploits a pathway first discovered in the 1990s. In an attempt to make petunias a deeper purple, researchers introduced an additional copy of a gene producing its purple pigment. But instead of darker petunias, they bred lighter ones. The reason was RNAi, an unknown defense mechanism that allows cells to break down double-stranded RNA (dsRNA) introduced from outside. The system likely evolved as a defense against viruses, which often have dsRNA. A protein called Dicer cuts the foreign RNA into small bits, which tag any complementary RNA they bind to for destruction by other cellular proteins.

    If an introduced RNA molecule isn't viral but corresponds to a gene in the cell itself, the system will turn against itself, destroying transcripts of that gene and silencing it. "We fool the defense system," says Guy Smagghe, an entomologist at Ghent University in Belgium. Millions have been spent on trials to use RNAi for silencing genes involved in cardiovascular and infectious diseases. But getting RNA into human cells has proven very difficult. For insects, on the other hand, it was surprisingly easy: Just feed them the RNA. Cells in the midgut of many larvae take up the molecules and help spread the signal throughout the insect's body.

    Scientists were quick to see the potential of killing insect pests by making plants produce insect RNA. The technology can be very specific because it affects only insects that have the target sequence, says entomologist Wayne Hunter of the U.S. Department of Agriculture in Fort Pierce, Florida. "You can feed it to psyllids and kill them, and you can feed it to leaf hoppers that eat the same plant and it won't kill them," he says. Indeed, by choosing highly specific gene sequences, scientists in 2009 showed they could kill any one of four fruit fly species while not harming the other three.

    Resisting resistances

    Monsanto will likely be the first to sell RNAi-based pesticidal seeds to farmers. The company has developed a transgenic corn plant expressing dsRNA based on a gene from the western corn rootworm, a beetle whose larvae cause a billion dollars' worth of damage in the United States alone. The RNA targets Snf7, a gene that helps ferry proteins to their destination inside the cell. In a 2012 paper, Monsanto scientists showed that silencing Snf7 stunts the growth of the larvae and kills them within days. Earlier this year, they also showed that it affects very few other species. "We think the science has been done," Moar says; getting regulatory approval is next. "We definitely expect to have a product out by the end of the decade."

    Others are working on different crops. Smagghe, in collaboration with the International Potato Center in Lima, is looking for genes to target in the sweet potato weevil, a beetle whose larvae ravage sweet potato fields all over the world. Researchers are also trying to silence genes in ants, caterpillars, and pollen beetles.

    But while locusts and beetle larvae respond well to RNAi, other insects seem less susceptible, Smagghe says, possibly because their saliva is better at breaking down RNA. Butterflies and moths are particularly resistant, and they include many major crop pests such as the cotton bollworm, the beet armyworm, and the Asiatic rice borer.

    Another potential problem is resistance. In a few places, the western corn rootworm has already become resistant to Bt corn—that's why scientists are urgently looking for alternatives in the first place. To develop resistance to RNAi, the western corn rootworm would have to change the genetic sequence of its Snf7 gene at multiple sites, which some experts say is unlikely to happen. Blair Siegfried, an expert on pesticide resistance at the University of Nebraska, Lincoln, disagrees. "My sense is that resistance to RNAi traits is just as likely to emerge as resistance against other agents we have developed," he says. However, combining Bt and RNAi in one plant, as Monsanto is doing, could delay that moment significantly, he says.

    Plants as patients

    But the biggest resistance may well come from a public that is skeptical, or even opposed, to GM crops. Environmental groups have already raised worries that RNA incorporated into plants could find its way into consumers' cells. They point to a 2012 paper by Chen-Yu Zhang of Nanjing University, who detected small RNAs from food plants in the blood of mice and humans. RNA intended to kill target insects could also end up in the human bloodstream, critics warn, with unknown consequences.

    Zhang's findings are controversial, however, and they have yet to be confirmed. Scientists have pointed out that a variety of biological barriers—including enzymes in saliva and blood and the ferociously acidic stomach environment—should break down any RNA. Monsanto researchers have argued that the RNAs found by Zhang could be the result of lab contamination and say the human equivalent of the mouse diet in his study would be 33 kilograms of cooked rice a day.

    Two recent studies published in RNA Biology also call the results into question. A team at Brigham and Women's Hospital in Boston fed athletes a diet of apples and bananas; they failed to detect RNAs abundant in these fruits in their blood afterward. Scientists at Johns Hopkins University School of Medicine in Baltimore, Maryland, gave monkeys a fruit shake and couldn't reliably detect plant RNAs in their blood either. "These two studies combined show that there is negligible uptake of microRNA from diets in mammals," says Kenneth Witwer, who led the Hopkins study.

    There's another strategy—Hunter calls "treating the plant as a patient"—in which dsRNA is simply added to the water used for irrigation. The molecules are sucked into the plants' vascular system and poison insects feeding on the sap. RNA could also be sprayed onto plants like a conventional pesticide, Hunter says. This would allow faster adaptation if resistance arises; scientists would just choose a new RNA snippet to apply, without having to build it into the plant's genome. Although humans would still ingest the RNA, the fact that plants aren't GM might make this approach an easier sell.

    Other scientists are skeptical. RNA molecules are so expensive that it's far more viable to have the plant itself produce them, Smagghe says. What's more, when applied to the water or sprayed onto leaves, RNA might rapidly degrade. Rather than treating our crops as patients, Smagghe says, it's better to give them the weapons to defend themselves.

  9. The War Against Weeds Down Under

    1. Erik Stokstad

    For decades, Australia's wheat farmers have had the worst weed problem in the world. Now, nonchemical weapons are helping to turn the tide.

    Scorched earth.

    One tool in Australia's approach to fighting weeds is to burn them after harvest, preventing seeds from germinating the next year.


    In 1788, when the First Fleet brought more than 700 English convicts to Australia, it also transported dozens of sheep. The animals were intended to help feed the penal colony, but they soon provided more than meat: Wool became one of Australia's main exports, which it remained for nearly 2 centuries. As settlers moved across the dry continent, they planted pastures for their flocks. Ryegrass, nutritious and fast-growing, was particularly popular forage. "Our early history is full of things that seemed like good ideas at the time, but that have come back to haunt us," says Christopher Preston, a weed scientist at the University of Adelaide in Australia. "The planting of ryegrass is one of them."

    The trouble started as the wool market crashed in the 1970s. Many sheep farmers switched to exclusively growing wheat in their pastures. Then ryegrass showed its ugly side. In wheat fields, the grass is an aggressive weed that competes for water and light, reducing yield. The plants produce so many seeds that, if left unchecked, they will choke a field completely. "It's our greatest nemesis," says Ray Harrington, a wheat farmer in Darkan, Western Australia.

    For a while, the solution was simple. Although there are many ways to fight weeds—plowing them up and rotating crops both help—the easiest and cheapest approach is to spray herbicides. Weed-killer was so effective that it allowed fewer workers to farm more land, boosting efficiency. By eliminating the need to plow, it also prevented soil erosion. Throughout the 1980s, production and profits continued to climb. But new difficulties arose. Within little more than a decade, ryegrass and other weeds began to develop resistance to herbicides. Farmers had to apply more and more of them to kill the plants, until the chemicals became virtually useless. Some moved on to other herbicides, often more toxic.

    It is a mistake that could easily be repeated around the world, making farming more complicated and expensive for large producers. "The real danger of resistance," says Dale Shaner, a weed scientist who recently retired from the U.S. Department of Agriculture, is that farmers will lose "the major tool that's given us inexpensive food and fiber." Through a combination of errors, this happened early, quickly, and widely in Australia. "There's never been so large a problem anywhere else in the world," says Stephen Powles of the University of Western Australia (UWA), Crawley.

    Thanks in part to Powles, Australia is also pioneering ways to deal with the problem. "He's the undeniable global leader in herbicide resistance," says Ford Baldwin, formerly a weed scientist with the University of Arkansas and now a consultant.

    The key to beating herbicide-resistant weeds, Powles says, is to abandon the hope of a silver bullet from the chemical industry. Instead, farmers must return to fighting weeds with a diverse arsenal of techniques. In Australia, these tactics are finally working, and Powles hopes to promote them in the rest of the world before more farmers lose effective herbicides. In Australia, he says, "we learned the hard way."

    What went wrong

    Tough opponent.

    Stephen Powles and his colleagues test weeds, such as these wild radish, for resistance to herbicides.


    Powles grew up poor, milking cows on his grandparents' struggling dairy farm in New South Wales. By age 15, he had dropped out of school. After several years working at a feed supply company, he entered Hawkesbury Agricultural College to study farming. He wound up with a Ph.D. in plant physiology and biochemistry from the Australian National University. By the time he finished a postdoc at Stanford University, he felt that his studies of photosynthesis were too far removed from the real world of agriculture.

    Just then, in 1983, the first cases of herbicide resistance were being reported in Australia. Sensing opportunity, Powles moved to the University of Adelaide. Patches of ryegrass had become immune to Hoegrass, a hugely popular herbicide. The product belongs to a family of herbicides that inhibit an enzyme called acetyl coenzyme A carboxylase, which helps plants make fatty acids. Farmers sprayed Hoegrass—which leaves the wheat unscathed—in early spring, to kill ryegrass seedlings.

    Several factors boosted the evolution of resistance. Ryegrass populations were large, and they had tremendous genetic diversity, thanks to the many varieties planted by sheep farmers over the century. In addition, ryegrass is cross-pollinated by wind, so genes shuffle frequently. But farmers made the situation far worse. By spraying Hoegrass year after year, they put a strong selection pressure on the plants. They were also diluting the herbicide in order to save money, which increases the risk of resistance. "Convincing people that it's a bad thing to do is not easy," Powles says. "We had to do the science."

    When Hoegrass stopped working well, farmers turned to a group of herbicides that block acetolactate synthase, an enzyme involved in making amino acids. But weeds soon evolved resistance to these herbicides as well. "Those are the ones that really hurt [to lose]," says Michael Walsh of UWA, a long-time collaborator of Powles. "They've been the most effective in our cropping system."

    Weeds will often become resistant to a specific herbicide while remaining vulnerable to others with different modes of action. Thanks to the weak concentrations that farmers were applying, however, ryegrass evolved a kind of cross-resistance that allowed it to rapidly break down a wide variety of herbicides. The mechanisms behind this are not fully understood. But it meant that Australian farmers lost four classes of herbicides in a matter of years. "They are absolutely cursed with the worst scenario you could come up with," says weed scientist David Shaw of Mississippi State University. Only two herbicide classes, called Photosystem II and long-chain fatty acid inhibitors, remain effective everywhere as a last line of chemical defense.

    In 1998, Powles founded the Australian Herbicide Resistance Initiative (AHRI), based at UWA. The group is primarily funded by government and industry fees on harvests. Fifteen scientists and technical staff members conduct field surveys, collect seeds, and test the plants for resistance. They also study the biochemical and genetic mechanisms of resistance. One of the first successes was a collaboration with DuPont that led to the introduction of a mandatory herbicide labeling program, in which each mode of action is clearly identified by a letter. AHRI also launched an educational effort called the ABC campaign to encourage farmers to use different types of herbicides each year.

    Catching seeds

    Like wildfire.

    Weeds have quickly evolved resistance to multiple herbicides all across Western Australia. On the map, each dot represents a study site.


    The key innovation of the AHRI approach has been to focus on weed seeds. Ryegrass seeds don't last more than a few years in the soil, so if farmers can prevent new seeds from getting into the soil, the number of sprouting weeds will shrink each year. For a long time, farmers were unintentionally doing exactly the opposite. When combine harvesters collect wheat, they loosen the ryegrass seeds from their stalks and cast them over the fields with the chaff, creating a worse problem the following year.

    Luckily, the propensity of ryegrass (and many other Australian weeds) to hang onto its seeds until harvest time is also a weakness that can be exploited. In the mid-1980s, a few Australian farmers hitched covered trailers, called chaff carts, behind their harvesters. They catch the chaff and weed seeds, then dump it in piles for burning. Their design took much trial and error. "A lot of guys couldn't get the chaff carts to work properly," Walsh says. "Some threw up their hands and walked away." Further tinkering has made chaff carts easier to use, notes Walsh, who expects them to become more popular despite their AUD $70,000 price tag.

    Rodney and Andrew Messina, farmers who grow wheat about 380 km north of Perth, developed a cheaper way to tackle weed seeds. In 1997, they modified their combines so that the chaff from each 10-meter swath would drop into a half-meter-wide line called a windrow. The idea was to burn the windrows after all the wheat has been harvested. Now, the brothers drive across all of their 12,000 hectares, igniting the windrows from a pickup truck outfitted with a gas torch. They set the fires at night, when the heat has eased, creating an eerie panorama of blazing lines as far as the eye can see. "It's a phenomenal amount of work," Rodney says. "But we've seen huge results from it." A few years ago, they bought a farm choked with ryegrass and wild radish. After a few years of burning windrows and spraying herbicides, the weeds are gone.

    The Messinas wanted scientists to evaluate the technique, so Walsh and Peter Newman of AHRI measured the temperatures inside the burning windrows and determined that they were highly effective at killing weed seeds. Since the research was completed in 2003, Powles says, windrow burning has been adopted by about 70% of farmers in Western Australia.

    The newest tool is an invention called the Harrington Seed Destructor. In 2005, Harrington, the Western Australia farmer, was looking for a way to crush weed seeds. He heard about a mining machine called a cage mill, which pulverizes coal with steel bars whirling at up to 1500 rpm. "I took one look at it and said, 'Nothing will survive in there,' " Harrington recalls. He built a prototype on a one-axle trailer, but ended up parking it behind a barn for a few years because he couldn't figure out how well it would work.

    Then he met Powles, who arranged for AHRI to build and test a research version of the contraption. Students spent hundreds of hours picking smashed ryegrass seeds out of the dust to see if they would germinate. Last year they reported in Crop Science that at least 95% are destroyed. An engineering company has launched a commercial version. Although the machine costs AUD $250,000, it is better for the soil than burning piles or rows of chaff because it returns all the nutrients in the chaff back into the fields.

    Measuring success

    Destroying weed seeds can be highly effective. AHRI researchers have studied a total of 31 large wheat fields with multiple-herbicide-resistant ryegrass. They've shown that farmers who target the seeds reduced weeds by 98%. A key to that success is also using herbicides—judiciously and at the correct dose—that are still widely effective, such as trifluralin and clethodim. Equally important is dedication: Farmers who managed their weed seeds every single year had much quicker success than those who did so less frequently, Walsh and colleagues report in Weed Technology this month.

    The benefit of mixing weed-seed-capture with herbicides and agronomic approaches, like crop rotation, is that it lowers the odds that resistance will evolve to any one approach. "You confuse the enemy," Powles says. "It's a bit like guerrilla warfare."

    AHRI puts a good deal of effort into disseminating these results—Powles himself has a knack for imagery—and encouraging farmers to adopt the techniques. Powles and his team have given thousands of presentations and workshops across the country. "Australian farmers will listen to this message because they've had a crisis," he says. Other researchers credit Powles's easy rapport with farmers, who consider him one of their own.

    Powles hopes to persuade farmers in other major agricultural countries to diversify their weed management as well. It's not an easy sell. In 2005, he spent 3 months in the United States, telling farmers what had happened in Australia and urging them to add more diversity to their weed management to prevent the evolution of resistance to glyphosate, which is widely used with genetically modified crops. "It was about a complete waste of time," Powles grumbles. North American weed scientists know the feeling. "We preach and preach and preach," says Patrick Tranel of the University of Illinois, Urbana-Champaign. "At the end of the day, [most farmers] will spend as little money as they can to produce as profitable a crop as they can." Later this month, Powles will try again, embarking on a 6-week speaking tour of the United States. It's not a minute too soon: Palmer amaranth and other herbicide-resistant weeds are becoming a nightmare, particularly in the South.

    Despite the progress in Australia, Powles knows that he can't turn his back for long. The most recent survey of Western Australia, in which AHRI staff members drove 15,000 km and sampled 466 wheat fields, found a large increase of herbicide-resistance in wild radish, a particularly nasty competitor with crops. Ultimately, Powles says, the measure of success in the war against weeds is whether farmers can grow their crops over the long haul and earn a decent income. It's a goal that is personal; when he was 10, his grandparents' failed farm was sold. The memory is still vivid.

    Seven years ago, Powles bought a farm himself, in Quairading, 180 km east of Perth. ("Probably an emotional rather than a rational judgment," he admits.) The 648-hectare property was thick with weeds resistant to multiple herbicides. Now he's running experiments there to check out the potential for ryegrass to also evolve resistance to the weed seed management he has advocated for so many years. If it can mature earlier and spread its seeds before harvest, for example, the weed might render the carts, the fires, and the seed destruction machines ineffective. But even if that happens, it will only reinforce his main message: Don't rely on any single tool.

  10. Vietnam Turns Back a 'Tsunami of Pesticides'

    1. Dennis Normile

    Convincing Vietnamese rice farmers to use less pesticide came down to letting them see the benefits for themselves.

    For years, the entomologists at Vietnam's Southern Regional Plant Protection Center in Long Dinh had tried to sell rice farmers on the benefits of reducing pesticide use—to little effect. So in 2001, they took a different tack: They challenged 950 farmers to try for themselves.

    In one plot, the farmers grew rice using their usual amounts of seed and fertilizer, spraying insecticide whenever they thought it was needed—which was often. In a nearby plot, they didn't spray at all for 40 days after planting and used less seed and fertilizer as well. To the farmers' surprise, the yield from the experimental fields was as good or better, while costs were lower, generating 8% to 10% more net income. From then on, they were convinced, recalls Chien Van Ho, who collaborated on the project.

    The exercise, designed with colleagues at the International Rice Research Institute (IRRI) of Los Baños, Philippines, was the first step in a campaign that Chien says has led Mekong Delta farmers to cut insecticide spraying from five times per crop cycle to once—or even none at all. Experts are now trying to replicate that success throughout Southeast Asia.

    Thanks to misunderstandings about pest control and heavy marketing, Asia's pesticide use has skyrocketed in recent decades. Pesticide imports by 11 Southeast Asian countries grew nearly sevenfold in value between 1990 and 2010, according to U.N. Food and Agriculture Organization (FAO) statistics, with disastrous results. Overuse indiscriminately kills beneficial as well as harmful insects and decimates bird and amphibian populations. Pesticides are also suspected of harming human health and are a common means for rural Asians to commit suicide (see story, p. 738).

    Ironically, the main target of this chemical warfare, the brown planthopper (Nilaparvata lugens), has become increasingly resistant to it. Over the past 5 years, planthopper outbreaks have devastated rice harvests throughout Asia—"but not in the Mekong Delta," says K. L. Heong, an IRRI insect ecologist. Thanks to the more judicious use of chemicals, natural predators helped keep planthoppers in Vietnam in check.

    Clean as a swimming pool

    The Green Revolution of the 1960s and '70s introduced sturdier plants that could support the heavier grain loads resulting from intensive fertilizer use. Rice production in Asia more than doubled. But it left farmers believing more is better—whether it's seed, fertilizer, or pesticides.

    Rice farmers became accustomed to spraying soon after planting, when they first saw signs of the leaf folder, which appears early in the crop cycle. That bug causes only superficial damage that doesn't reduce yields. Worse, early spraying also takes out the frogs, spiders, wasps, and dragonflies that prey on the brown planthopper, which arrives later and is far more dangerous.

    Let 100 flowers bloom.

    Vietnamese rice farmers are encouraged to use less pesticide and to grow flowers and vegetables on the banks of their paddies.


    Instead of "landing in a sea of sharks," planthoppers find something as "clean as a swimming pool," Heong says. What's more, tests have shown that killing planthoppers now takes pesticide doses 500 times greater than in the past. More and more planthoppers survive to suck sap from the young rice plants, causing them to wither.

    As early as the 1980s, IRRI and the FAO convinced some Southeast Asian governments that with so-called integrated pest management (IPM), natural predators could control planthopppers. In 1986, Indonesia banned 57 pesticides and completely stopped subsidizing their use. But progress was reversed in the 2000s, when growing production capacity, particularly in China, unleashed a "tsunami of pesticides," says FAO entomologist Peter Kenmore. Even some in the agrochemical industry concur. "We all agree that in Vietnam, farmers have overapplied pesticides in some production environments," says Kee Fui Kon, who oversees rice-related R&D at the Swiss agrochemical giant Syngenta.

    Radio soap opera

    In Vietnam, the Mekong Delta trial helped change conventional wisdom among farmers and agricultural officials. The study led to the "three reductions, three gains" campaign, to convince farmers that cutting the use of seed, fertilizer, and pesticide would boost yield, quality, and income. Word was spread through posters, leaflets, TV commercials, and a serialized radio soap opera, broadcast in 2004, that featured a rice farmer who gradually became convinced of the benefits of IPM. It didn't hurt that a 2006 planthopper outbreak hit farmers using insecticides harder than those who didn't.

    More recently, the Plant Protection Center and IRRI have also been encouraging farmers to grow flowers, okra, and beans on the banks of paddies, instead of stripping vegetation, as was typical. The plants attract bees and a tiny wasp that parasitizes planthopper eggs, while the vegetables diversify farm incomes. Chien says that few Mekong Delta farmers now routinely use insecticides, though many still use fungicides.

    "I think that there are signs that things have gone pretty well in Vietnam recently," Kenmore says. Other experts are reserving judgment. "I take the reports [of reduced insecticide use] at face value, but as a scientist I would like to see data," says agroecologist Steve Wratten of Lincoln University in Canterbury, New Zealand. Geoff Gurr of Charles Sturt University, Orange, in Australia, who collaborates with Heong and Chien, says that they are now crunching data from studies on pesticide use and the effects of planting flowers and vegetables; a paper will be ready soon.

    Farmers' foe.

    Brown planthoppers have become increasingly resistant to insecticides.


    Syngenta's Kon says that there is still a role for insecticides, especially those targeting other pests, such as stem borers, the larvae of several moth species that feed on rice plants. The company's internal data show that yield gains of 21% can be achieved with the proper use of pesticides, he says.

    Other countries are taking note of Vietnam's approach. In 2010 and 2011, massive planthopper outbreaks hit 400,000 hectares of Thai rice fields, causing losses of about $64 million. "We're starting to increase the awareness that farmers are losing a lot because of the misuse of pesticides," says Kukiat Soitong, an extension specialist with the Thai Ministry of Agriculture and Cooperatives. The Thai government is now pushing the "no spray in the first 40 days" approach.

    All of these initiatives, Heong says, "have to overcome very powerful marketing forces," such as bundling pesticides in packages with seeds and fertilizer, offering incentives for volume purchases, and hyping the benefits. Here, too, Vietnam is taking action. A proposed law calls for licensing pesticide dealers and government approval of advertisements to prevent exaggerated claims. FAO pest management expert Kevin Gallagher thinks that such regulation is needed throughout the region. "Farmers everywhere are influenced by advertisements," he says. There is "a lot of misinformation everywhere, all the time."

  11. In Rural Asia, Locking Up Poisons to Prevent Suicides

    1. Mara Hvistendahl

    Pesticide ingestion accounts for one-third of the world's suicides. Can a simple plastic lockbox keep toxic chemicals out of desperate people's hands?

    When Flemming Konradsen arrived in Sri Lanka's North Central Province in 1993, he aimed to find new ways to control malaria and Japanese encephalitis. But Konradsen, an environmental health biologist at the University of Copenhagen, quickly realized that these mosquito-borne diseases were hardly the region's worst health problem. As others documented in a paper a few years later, people who had intentionally swallowed pesticides occupied far more beds in a provincial hospital than did patients with any one disease.

    Farmers in the area used insecticides and herbicides liberally, giving them and their family members ready access to very toxic chemicals at moments of stress. The prevalence of self-poisoning was "very difficult to ignore," Konradsen recalls. Before long, he had shifted his research from mosquitoes to self-harm. Twenty years later, he and colleagues have embarked on a massive study to find out if a specially developed lockbox can reduce the suicide rate by keeping pesticides out of the hands of desperate people.

    A little-known problem in the Western world, pesticide ingestion is the leading global means of suicide, accounting for roughly one-third of the estimated 1 million cases annually. Scientists say the easy availability of pesticides contributes to rural Asia's high suicide rates. Asians who kill themselves often have no discernible mental illness; rather, they make impulsive decisions during brief periods of emotional distress (Science, 23 November 2012, p. 1025). In the United States, a loaded gun in the home makes adolescents significantly more likely to die by suicide; in Asia, people "don't have guns—they have pesticides," says toxicologist Michael Eddleston of the University of Edinburgh in the United Kingdom.

    Reducing access to highly toxic pesticides, Eddleston and colleagues say, is critical to lowering the region's suicide rate. But until recently, international discourse was "dominated by the view that pesticides were an environmental and maybe an occupational issue," Konradsen says.

    Fatal gulps

    During the Green Revolution of the 1970s, countries like Sri Lanka turned to organic chlorines and organic phosphates to boost crop production. Suicide rates also shot up, Eddleston says: "People taking poison would say 'I'm going to go do a Folidol'"—a brand of methyl parathion, a potent insecticide. With some pesticides, as little as 50 milliliters—a few gulps—can be fatal. Depending on the chemical, death can be triggered by convulsions, respiratory failure, or organ or lung damage.

    Drawing attention to this problem was far from easy. Two major treaties governing hazardous pesticides don't mention self-harm at all. Environmental activists don't often address the misuse of pesticides as poison because it makes it "more difficult to highlight the responsibility of the producer," Konradsen says.

    Nonetheless, Sri Lanka phased out imports of all World Health Organization (WHO) hazard class I pesticides—the most toxic group—between 1991 and 1995. In 1998, the country also banned endosulfan, a moderately toxic class II pesticide. The suicide rate fell by 50% between 1995 and 2005, even though hospital admissions for pesticide poisoning increased, Eddleston and epidemiologist David Gunnell of the University of Bristol in the United Kingdom noted in a 2007 paper. "It wasn't that people stopped poisoning themselves—they just didn't die," Eddleston says.

    Deadly toll.

    Easy availability of pesticides has made self-poisoning the most common means to commit suicide in Sri Lanka. Bans on some chemicals have helped reverse the trend.


    Still, self-poisoning remained a major cause of death. In search of additional solutions, Konradsen began working with a local community-based organization and manufacturers in 2004 to fashion a lockbox to store the chemicals safely. Since then, they've tried out a range of designs. A wooden version was too popular with bees and termites. Another prototype made of cement led to broken pesticide bottles, while versions with flimsier lids got trampled by elephants.

    For the trial, the team settled on a waterproof, UV-resistant contraption made of plastic, featuring a padlocked inner lid inside a sturdy outer lid that protects the lock from weather damage. The box is partly buried in a field, and the key is generally kept by the family member who applies pesticides—typically the father. The 5-year study, on which Eddleston, Gunnell, and Konradsen are co-investigators, involves 225,000 people and is funded by the Wellcome Trust. Researchers began distributing the lockboxes in 2011 in dozens of randomly selected villages, using another group of villages as controls. The last of 18,980 boxes was distributed in May.

    The goal is to see whether the boxes lower the incidence of suicide attempts—and if so, at what cost per life saved. "It seems like a bit of a no-brainer" that there would be a clear effect, Gunnell says. But smaller studies have found mixed or even adverse results. Some farmers moved the box closer to home—apparently feeling that the locked chemicals posed less of a threat—bringing them into closer reach during an impulsive outburst. Waning enthusiasm was another problem: In one study of more than 160 Sri Lankan households, only 55% of containers remained locked after 2 years. And several people in the current study have already broken into boxes and ingested pesticides. (None have died.)

    Desperate measure.

    A man is treated after ingesting pesticides in a hospital in Sri Lanka.


    Konradsen says that industry is enthusiastic, touting his previous research as "the solution to all kinds of issues." But at best, lockboxes should supplement bans on toxic chemicals, says Shah Ebrahim, a public health scholar at the London School of Hygiene & Tropical Medicine who chairs the study's independent ethics and data monitoring board. "This is not a panacea."

    Richard Brown, head of global stewardship for Syngenta, says that the company is running its own pilot studies on secure storage in India, Sri Lanka, and Suriname with WHO and other partners; Brown is also on the larger trial's advisory board. (The trial receives no industry funding.) There is no "magical fix" for suicide, he says; counseling services and social norms need to be addressed as well. But lockboxes encourage community involvement on the issue of suicide, Brown says, while bans "may encourage farmers to look for banned products on the unregulated black market."

    If they prove effective and affordable, lock-boxes may be a viable option for other countries as well, such as India and China. Konradsen ultimately hopes to see them become part of a "more holistic" approach to pesticides, including bans. Promoting minimal pesticide use, he notes, would hit a number of key targets—reducing environmental impact, contamination in food, occupational and suicide poisonings, and the development of resistance in disease vectors—all in one fell swoop.

  12. Growing Up With Pesticides

    1. Amanda Mascarelli*

    Long-term studies of the effects of pesticides and other environmental chemicals on the very young brain are coming up with worrisome results.

    Mind at risk?

    A boy is playing near a lettuce field in Salinas Valley.


    SALINAS VALLEY, CALIFORNIA—It's a sunny July day, sweltering by midmorning. Fields with meticulously maintained rows of lettuce and bushy, berry-laden strawberry plants stretch to the horizon. Farm workers wearing brightly shaded headscarves and layers of clothing—most of them low-income Mexican immigrants—dot the fields. This is "America's salad bowl," a region that grows much of the produce found in grocery stores throughout the country.

    At about 3 p.m. in the afternoon, Guillermina Aguilar walks into a small office with her husband and their 12-year-old son Eric, who's about to undergo a series of tests. Aguilar and her family are part of a long-term study into the effects of pesticides and other environmental chemicals at the Center for the Health Assessment of Mothers and Children of Salinas, or CHAMACOS, which is also Mexican slang for "little kids."

    Aguilar enrolled in the study when she was pregnant with Eric. At the time, the family lived two blocks from the fields, where the pungent, sweet odor of pesticides often hung heavy in the air. "Sometimes in the mornings I remember I would ask my husband, 'What's that smell?'" Aguilar recalls. But they became accustomed to it. "That was normal for us at that time," Aguilar says. Today she lives in Arkansas; Eric's 12-year assessment takes place during a family visit.

    The program, run by the University of California (UC), Berkeley, is one of three U.S. studies that have followed children since the late 1990s to investigate the impact of chemicals in the environment on their brains. The Berkeley program focuses on an agricultural area in California; studies at Columbia University and Mount Sinai School of Medicine look at multiethnic, low-income inner city families in New York City.

    The outcomes so far are troubling, although they have been questioned by the pesticide industry. The studies suggest that organophosphates, a widely used class of pesticides that act on the central nervous system, hamper the development of some parts of the brain in children, leading to lower IQs and attention problems. Preliminary evidence also suggests that pesticide exposure may affect sexual differences in certain brain regions during early childhood development.

    A main culprit in the Columbia study, chlorpyrifos, was phased out in 2001 for most residential use, and urban exposure in the United States has dropped dramatically—but it's still widely used in agriculture. And a whole generation may already be suffering subtle but prolonged effects, says epidemiologist Virginia Rauh, deputy director of the Columbia Center for Children's Environmental Health.

    Critical stages

    Research in lab animals and farm workers has shown that chronic exposure to high doses of pesticides is associated with neuro-degenerative diseases such as Parkinson's disease and cognitive deficits. More recently, researchers started looking at how exposure in the womb and in infancy affects the developing brain—a quest spurred in part by a growing awareness of neurobehavioral and neurodevelopmental disorders such as attention deficit hyperactivity disorder (ADHD) and learning disabilities. In the 1990s, "we realized that we needed to understand what children were being exposed to in the womb and in the early months and years of their lives," says Frederica Perera, director of the Columbia center.

    All three studies recruited hundreds of pregnant mothers in the late 1990s, measured their exposure to environmental chemicals, and gave their kids a battery of tests at various intervals. The Columbia researchers also obtained umbilical cord blood samples directly after birth, allowing them to measure fetal exposure to several pesticides directly; the Berkeley team collected urine samples during pregnancy and early childhood, and searched for pesticides' breakdown products. The researchers compared the intellectual development of children with varying levels of pesticide exposure within each group, controlling for confounding variables such as sex, race or ethnicity, maternal education, family income, and other toxic exposures.

    Early on in the Berkeley study, infants with high fetal exposures showed abnormal reflexes. At age 2, the highly exposed children had lower mental development, and the researchers found an increase in ADHD-like behaviors at age 5. At age 7, highly exposed children scored 7 points lower on the fulls-cale IQ score, which includes tests of verbal comprehension, working memory, processing speed, and perceptual reasoning—a drop similar to that found in studies of childhood lead exposure. It translates to about a 6-month developmental lag, says reproductive epidemiologist Kim Harley of the UC Berkeley center.

    While the California study looked at a range of organophosphates used in agriculture, the Columbia team zoomed in on chlorpyrifos, which was widely used indoors to kill ants, termites, and cockroaches. Even after indoor use largely ended in 2001, it's still used to control agricultural pests under the Dow Chemical trade name Lorsban. The company also continues marketing chlorpyrifos for residential use in developing countries.

    The Columbia team realized that chlorpyrifos might be important after they discovered detectable levels in the umbilical cord blood samples from 71% of their pregnant women in the late 1990s. "That was a wake-up call for all of us," says Columbia University molecular epidemiologist Robin Whyatt. "Whereas one generally thought about pesticides as an agricultural risk, it really became clear that in New York City, because of the cockroach problem, they are definitely an urban risk as well."

    The team found that infants with high exposures to chlorpyrifos and another commonly used organophosphate called diazinon had lower birth weight and birth length, "on the order of what one would see with active cigarette smoking during pregnancy," Whyatt says. The team also reported abnormal reflexes in newborns, as well as deficits in IQ and attention, and behavioral problems as the children matured.

    Rauh, along with Columbia developmental neuropsychiatrist Bradley Peterson, also performed an MRI study on the brains of 40 children aged 5 to 11, half of them from the high exposure group. In a 2012 paper in the Proceedings of the National Academy of Sciences, they reported that the volumes of a number of brain regions that are important in emotion, social cognition, and inhibition were altered in highly exposed children. What's more, some normal sex-specific differences in the sizes of certain brain regions were not seen in children with high prenatal exposure—findings consistent with effects seen in animals. That suggests chlorpyrifos may interfere with normal sexual differentiation of the brain, Rauh says—although what that means for the kids is unclear. The team is now conducting a study in 250 children to confirm the results.

    Chlorpyrifos and other organophosphates work by inhibiting cholinesterase, a family of enzymes that break down acetylcholine, a neurotransmitter that plays many key roles in the brain. When exposure occurs during prenatal development, these compounds "essentially misdirect the assembly of the brain," says Theodore Slotkin of Duke University in Durham, North Carolina, who has extensively studied pesticides' effects on animals.

    State of the art

    Dow Chemical has long tried to poke holes in the research that finds detrimental effects from pesticides. In response to the imaging study, for instance, the company issued a statement pointing to what it says are limitations in the research, such as the fact that the scans "provide only a single snap-shot in time," and that confounding factors were controlled "only imperfectly or not at all." A company spokesman adds that "no mechanism of action has been determined by these researchers that would explain how these outcomes would come about."

    Joseph Braun, an epidemiologist at Brown University, calls the imaging study "cutting edge and very novel" but cautions that replication is necessary. Bruce Lanphear, a pediatric epidemiologist at Simon Fraser University, Vancouver, in Canada, says that the MRI results weren't surprising. In 2008, he and others reported similar structural brain changes associated with childhood lead exposure. Lanphear calls the cohort studies "highly regarded" and "state of the art." "Pesticides were designed to be neurotoxic," he says. "Why should we be surprised if they cause neurotoxicity?" (Neither Braun nor Lanphear was involved in the study.)

    The indoor regulation on chlorpyrifos has reduced exposure in some populations, and use of that compound and other organophosphates is steadily declining in U.S. agriculture as well. But researchers worry about the safety of their replacements, such as the pyrethroids, which now comprise the majority of household pesticides and are also heavily used on farms. Harley likens the succession of chemicals to a game of "whack-a-mole," in which one compound is banned, only to be replaced by another whose safety is not assured.

    As noon approaches under the relentless California sun, workers—men and women—are bent over, quickly and methodically shaking the strawberry plants, plucking the reddest and ripest of the berries, then stacking them inside clear, plastic cartons labeled with common household names. It would be difficult to grow all of this produce at the current prices without pesticides; the CHAMACOS researchers are the first to admit that it's a complex problem. "Now that we've been in the Salinas Valley for 13 years, we get to see all sides of the issue," says Berkeley epidemiologist Brenda Eskenazi, who heads the study.

    Harley agrees—but given the choice, she buys mostly organic produce. Not just to protect her own children, she says, but those of the men and women working in these fields.

    • * Amanda Mascarelli is a science writer in Denver. Her reporting was supported by the California Endowment Health Journalism Fellowships, a program of the University of Southern California's Annenberg School of Journalism