# News this Week

Science  22 Oct 2010:
Vol. 330, Issue 6003, pp. 432
1. Environment

# After Red Mud Flood, Scientists Try to Halt Wave of Fear and Rumors

1. Martin Enserink

KOLONTÁR, HUNGARY—Shortly after a red river from hell tore through this village on 4 October, destroying lives and homes, Hungary's junior minister for environmental affairs, Zoltán Illés, said aloud what many feared: Nobody really knew what was in the caustic sludge—a byproduct of the aluminum industry whose pH can reach a dizzying 13—that had broken through a nearby reservoir.

But scientists at the Institute of Materials and Environmental Chemistry in Budapest begged to differ. The institute, part of the Hungarian Academy of Sciences, has done research on the toxic residue—which chemists call “red mud”—for decades. “We know red mud better than we know our wives,” says László Kótai, a chemical engineer at the institute.

Kótai is part of a nine-member scientific task force, called together by the Hungarian government, which has found itself battling not just mud but also a rising tide of rumors and misinformation. Illés, for instance, said that the sludge was radioactive and could cause cancer, and the environmental group Greenpeace announced that it contained dangerous levels of heavy metals. Those claims led to fears of a widespread ecological catastrophe—including a poisoning of the Danube, one of Eastern Europe's major rivers. But Illés has dropped his claim about radioactivity, and scientists say Greenpeace's report was alarmist and unscientific.

Two weeks after the disaster, Kótai and other scientists say its environmental impact may be less severe than widely broadcast images suggested at first. They don't want to diminish the human tragedy: Nine people have died and more than 100 have been injured; many suffered burnlike wounds from the sludge's alkalinity. But much of the sludge can be removed physically and taken back to one of the company's intact reservoirs; the remainder can be neutralized with mild acids, says János Szépvölgyi, an environmental chemist who heads the task force. Task force members predict only minimal effects on the ecology of the Danube and don't think drinking water is at risk. “It's not as dramatic as it seems,” says Tamás Németh, the academy's general secretary and a soil scientist himself. “We can handle this.”

About a million tonnes of red mud poured out when the dam on reservoir 10 of the Ajkai Timföldgyár alumina factory near Kolontár broke just after noon on 4 October. The sludge is formed during the so-called Bayer process, when bauxite ore is pressure-cooked with sodium hydroxide in giant reactors to extract aluminum hydroxide. The residue was stored in giant reservoirs right next to the factory, as it is at similar facilities around the world.

What caused the break is still under investigation. Some environmental groups had suggested that Hungary's red mud reservoirs, a legacy of the communist era, were poorly monitored and prone to breaks. The Hungarian task force, which also includes biologists and ecologists, has set out to map the impact of the release and provide the government with advice on how to limit the harm. Aside from the sheer physical impact of the initial wave—some Kolontár residents likened it to a red tsunami—the sludge's main problem is its deadly alkalinity, says Szépvölgyi. The Torma, a small stream near the village that ultimately flows into the Danube, turned red and is now almost completely lifeless. But the environmental damage downstream was reduced, says Szépvölgyi, partly by dilution and possibly because government workers dropped large amounts of fertilizers and calcium sulfate into the rivers to bring down the pH. Elevated pH values of between 8 and 9 were measured locally in the Danube for a few days, but they have come down, says Szépvölgyi. No major fish die-offs in the Danube have been reported.

Nor do task force members believe heavy metals will be a major problem. During a press conference on 8 October, Greenpeace announced that red mud from Kolontár contained high levels of arsenic, chromium, and mercury, suggesting that illegal dumping had occurred in the sludge pond before it broke. For arsenic, the level was 25 times higher than the limit for drinking water, the group said.

But that's a nonsensical comparison because nobody is planning on drinking the sludge, says Szépvölgyi. A better reference is the arsenic level allowed in organic sludges that Hungarian farmers are permitted to spread on their lands; the level measured by Greenpeace was just slightly above that. Szépvölgyi also criticizes the group for basing its findings on a single sample. The sludge wasn't homogenous, he says, and the task force's own measurements have found varying levels of heavy metals at different locations—but none dangerously high, Szépvölgyi asserts.

Greenpeace spokesperson Szabina Moses says the group stands by its findings and that the academy scientists are downplaying the risks. “We're talking about arsenic. I don't have to be a scientist to feel that that is dangerous,” Moses says.

Initial news stories suggested that Kolontár and Devecser, a bigger town farther downstream, might have to be abandoned altogether. That was an exaggeration, task force members say. When Kótai gave Science a tour of the area last week—expertly talking his way past police roadblocks—cleanup activities in Kolontár were in full swing. Trucks were hauling away tonnes of red mud; a few homes were clean again, and a handful of residents, looking somber, were returning. Many yards and sidewalks were covered with calcium sulfate. The compound—which makes streets look as if they're covered with dirty snow—not only helps neutralize the mud but also prevents it from becoming an easily dispersible powder once it dries. Instead, the mix forms a cake that can be removed with shovels.

What will happen to the surrounding farmland? The layers of red mud there vary from 1 or 2 centimeters to more than 10 cm thick. Some will need to be removed, but small quantities can probably be mixed in with the soil, says Németh. The alkalinity can be neutralized with mild acids, such as acetic acid or humic acid, a complex organic mixture that occurs naturally in the soil. Studies will have to show whether crops can be grown safely in these areas, Németh adds, but it might be wise to stick with biofuel crops or trees for the foreseeable future. “I don't think anybody will want carrots and potatoes from this area anyway.”

As Science went to press, another breach from the same reservoir threatened. But a new dam would divert most of the sludge, even if that happened, says Németh. What's more, the reservoir contains far less fluid, so any escaping mud would travel slowly and only a couple of hundred meters, models show.

Amid the media frenzy, scientists say they are trying to be the voice of reason. When Kótai encountered one roadblock in Devecser, two police agents wearing rubber boots and facemasks asked if they were at risk as they guarded a street full of deserted homes. Kótai tried to reassure them. “They are scared,” he said after he got back into his mud-covered Volvo. “They have heard so many stories.”

2. Exoplanetary Science

# First Goldilocks Exoplanet May Not Exist

1. Richard A. Kerr

Astronomers have begun debating whether the first claimed habitable planet circling another star is a figment of their data analysis. At a meeting last week in Turin, Italy, a group of exoplanet hunters announced that its observations show no sign of Gliese 581g, the Goldilocks planet on which conditions are just right for harboring life. Only a couple of weeks earlier, a rival group had announced with much fanfare its discovery of the long-sought Earth-like, habitable planet.

“Of course, it's not easy to definitively rule out something,” says exoplanet astronomer Ray Jayawardhana of the University of Toronto in Canada, but the “results presented here at Turin are at least raising some doubts.”

Such controversy is not surprising. To be detectable, Gliese 581g (if it's there) must gravitationally tug on its star strongly enough for astronomers to recognize the resulting stellar wobble in observations of the varying frequency of starlight. But at about three times the mass of Earth, Gliese 581g would be among the smallest of known exoplanets, and four other planets—three of them much more massive—are tugging on the same star.

To sift out any particularly subtle stellar wiggles, exoplanet hunter Steven Vogt of the University of California, Santa Cruz, and colleagues combined two series of observations. One 11-year-long data set consisted of 122 measurements made by Vogt and colleagues. The other set was 4.3 years long and consisted of 119 measurements published earlier by a rival consortium headquartered at the Observatory of Geneva in Switzerland. In a 29 September press conference and in a paper subsequently published in The Astrophysical Journal, the American group announced the discovery of an exoplanet massive enough to hold on to a life-sustaining atmosphere, orbiting its star every 37 days. That close to a small, faint star, a planet's water could remain liquid.

The first known habitable planet looked like a done deal until a member of the Swiss group, exoplanet hunter Francesco Pepe of the University of Geneva, made his announcement at the Astrophysics of Planetary Systems meeting in Turin. Since publishing the data set the American group had used, the Swiss had extended their record to 6.5 years, including a total of 180 measurements. “We do not see any evidence for a fifth planet … as announced by Vogt et al.,” Pepe wrote to Science in an e-mail from the meeting. On the other hand, he added, “we can't prove there is no fifth planet.”

Confirming or denying Gliese 581g will likely require agreement that someone's data analysis went awry. If data quality turns out to be a wash, the two groups' different approaches to data analysis may offer an explanation, says astrophysicist Alan Boss of the Carnegie Institution for Science in Washington, D.C., who was at the Turin meeting. The Swiss group's analysis assumes the orbits of Gliese 581's planets to be elongated in accord with the observations, he notes. If those orbits are in fact circular, as the American group believes, the supposed elongation could mask the presence of a smaller fifth planet. But even if data-analysis issues are not ironed out, all agree, a few more years of observation should do the trick.

3. Planetary Science

# How Wet the Moon? Just Damp Enough to Be Interesting

1. Richard A. Kerr

“The Moon Is Wet,” read many a headline in the past year, at times with an exclamation point. That's an overstatement, with or without the exclamation point, says lunar scientist Paul Spudis of the Lunar and Planetary Institute in Houston, Texas. But “the old statement that the moon is ‘bone-dry’ is not correct either. What we have found is that the moon has a hydrosphere, it has a water cycle.”

But the moon's hydrosphere is nothing like Earth's watery regime. None of the moon's water is ever liquid. Water in its reservoirs can be imperceptibly sparse, flows into its reservoirs may proceed a few molecules at a time, and none may ever leave. And, as seen in the five reports of new water-related results from the moon beginning on page 463, many enigmas remain.

A year ago, researchers found the first water on the moon, frozen water buried in Cabeus crater near the south pole. Blasted into view by a plunging spent rocket stage (Science, 19 March, p. 1448), this subsurface ice is now pegged at only about 6% by mass of the top meter or two of lunar soil, according to LCROSS (Lunar Crater Observation and Sensing Satellite) mission team members reporting on page 463. This LCROSS water was the prize in a decades-long search driven most recently by NASA's push to sustain astronauts returning to the moon. But since the LCROSS mission, the Obama Administration and now Congress have turned away from sending humans back to the moon (Science, 1 January, p. 18).

There's still plenty in recent results to intrigue researchers, however. For starters, the controversial radar probing of the subsurface that ignited the hunt for lunar water (Science, 13 March 1998, p. 1628) was misinterpreted, the LCROSS result shows. No radar could detect such sparse ice. And the remote probing for subsurface hydrogen that led LCROSS team members to Cabeus was misleading. The Lunar Exploration Neutron Detector (LEND) instrument flying on NASA's Lunar Reconnaissance Orbiter (LRO) (p. 483) picked up a strong hydrogen signal. But it wasn't mostly from water's hydrogen, as team members originally thought. LRO's Lyman Alpha Mapping Project found that at least as much hydrogen in the LCROSS impact plume took the form of molecular hydrogen, H2, as was locked up in H2O (p. 472). How the molecular hydrogen got there remains unclear.

Results from LCROSS, LRO, and other recent moon missions confound as well as illuminate. Radar probing from India's recently deceased Chandrayaan-1 orbiter picked up no reflections from LCROSS's Cabeus crater, consistent with sparse ice. But strong reflections from a couple of dozen craters around the lunar north pole suggest an icy bonanza: massive, nearly pure ice just beneath the crater floors. “How that would come about I haven't a clue,” says Spudis, who is principal investigator of the Chandrayaan-1 radar.

The conventional explanation for ice in polar craters like Cabeus—whose floor is in permanent shadow and thus hovers near 40 degrees above absolute zero—is that icy asteroids or comets strike somewhere on the moon, and some of the resulting water vapor reaches a permanently shadowed crater's deep chill and freezes out there. But such cold trapping would only fill the empty space in the soil, not form nearly pure ice. No one really knows how nearly pure subsurface ice would form.

Adding further confusion, LEND team members also report that surprisingly high amounts of hydrogen lurk near the south pole in places that get at least some sunshine. It turns out that temperatures measured from LRO and reported on page 479 can be low enough to allow billion-year-old ice in sunlit areas as long as there are at least a few centimeters of overlying, insulating soil. More perplexing is LEND's failure to find abundant hydrogen in many permanently shadowed craters that are just as cold as Cabeus. “The data's not pointing to a single process for emplacing water,” concludes Anthony Colaprete, LCROSS's principal investigator from NASA's Ames Research Center in Mountain View, California.

Even at its moistest, the lunar hydrosphere isn't very wet. Several teams of spectroscopists observing the moon from different space platforms have reported detecting water on the surface (http://scim.ag/whiff-of-water). But they are talking about layers just a few molecules thick.

One team reported a decrease in such surface water as the lunar day wore on, suggesting that heating frees water stuck to the surface to fly about the vanishingly thin lunar “atmosphere”—another water reservoir—until again hitting and sticking to the surface. This leapfrogging process might explain how water from impacting meteorites can bounce into a cold trap instead of escaping from the moon entirely.

Reports of wetness in rare minerals that Apollo astronauts brought home might also be overblown. From those analyses, some geochemists have inferred that the ancient moon's interior harbored a few tens of parts per million of water. But since those claims, a group analyzing chlorine isotopes in Apollo samples concluded that the lunar interior has always been bone-dry at less than 10 parts per billion (http://scim.ag/beneath-the-surface-of-the-moon). At stake, hydrologically speaking, is whether gas-emitting volcanoes on the moon ever contributed to the lunar hydrosphere.

As Colaprete notes, the question of lunar water “is complicated.” Planetary scientist David Paige of the University of California, Los Angeles, thinks “we've done what we can remotely. My guess is the ultimate solution is in situ exploration.” If the humans aren't game, bring on the robots.

4. Animal Science

# Rinderpest, Deadly for Cattle, Joins Smallpox as a Vanquished Disease

1. Dennis Normile

Rinderpest, an infectious disease that has decimated cattle and devastated their keepers for millennia, is gone. The United Nations Food and Agriculture Organization (FAO) announced on 14 October in Rome that a 16-year eradication effort has succeeded and fieldwork has ended. “This is the first time that an animal disease is being eradicated in the world and the second disease in human history after smallpox,” FAO Director-General Jacques Diouf said in his World Food Day address in Rome the next day.

“It is probably the most remarkable achievement in the history of veterinary science,” says Peter Roeder, a British veterinarian involved with FAO's Global Rinderpest Eradication Programme (GREP) from its launch in 1994 until he retired in 2007. For the veterinarians who participated in the effort, the achievement is particularly poignant. “I thought this could not be done before I passed away,” says 79-year-old Yoshihiro Ozawa, who, as FAO's chief veterinary officer in the late 1980s and early 1990s, helped launch GREP. “I'm very lucky to see the end of [rinderpest].”

One formality remains: The Paris-based World Organisation for Animal Health (OIE) still must complete the certification of a handful of countries as rinderpest-free. OIE is likely to adopt an official declaration recognizing the demise of the disease at its May assembly. Meanwhile, animal-disease fighters have already been applying lessons learned from the rinderpest campaign and pondering which animal disease might be the next target for eradication.

Although nearly forgotten in much of the West, as recently as the early 1900s, outbreaks of rinderpest—from the German for “cattle plague”—regularly ravaged cattle herds across Eurasia, often claiming one-third of the calves in any herd. The virus, a relative of those that cause canine distemper and human measles, spreads through exhaled droplets and feces of sick animals, causing fever, diarrhea, dehydration, and death in a matter of days. It primarily affects young animals; those that survive an infection are immune for life.

When the virus hit previously unexposed herds, the impact was horrific. In less than a decade after the virus was inadvertently introduced to the horn of Africa in 1889, it spread throughout sub-Saharan Africa, killing 90% of the cattle and a large proportion of domestic oxen used for plowing and decimating wild buffalo, giraffe, and wildebeest populations. With herding, farming, and hunting devastated, famine claimed an estimated one-third of the population of Ethiopia and two-thirds of the Maasai people of Kenya and Tanzania.

European countries gradually eliminated rinderpest in the early 20th century through conducting disease surveillance, controlling animal shipments, and culling sick and exposed animals. It continued to afflict Asia and Africa in the second half of the century, re-emerging after at least one eradication campaign was ended in the mistaken belief that the virus had been conquered.

In 1994, when rinderpest was entrenched in central Africa, the Arabian Peninsula, and a swath stretching from Turkey through India and to Sri Lanka, FAO brought together three regional rinderpest-control programs into GREP and set the goal of eliminating the disease by 2010. “At times, I was pessimistic that we were going to get anywhere,” says Roeder. The key technical breakthrough was the recognition that the virus was re-emerging from just a handful of reservoirs that could be the targets of intensive surveillance and vaccination campaigns. In 1990, Jeffrey Mariner, then at Tufts University School of Veterinary Medicine, had developed an improved vaccine that did not require refrigeration up to the point of use. This allowed vets and technicians to backpack vaccine into remote areas. One of the reservoirs was in the heart of war-torn eastern Africa, where vet services had broken down and international agencies dared not send personnel. GREP relied on local pastoralists to track the disease and on trained community animal-health workers to administer the vaccine to quell outbreaks.

Roeder says a second key to success was that as GREP made progress, countries initially skeptical or reluctant to share information on their rinderpest problems started cooperating. The virus was last detected in 2001 in wild buffaloes in Meru National Park in Kenya, on the edge of the Somali ecosystem.

What comes next? Some veterinary experts question whether the international community is ready to take on another massive eradication campaign, but one disease mentioned as a possible eradication target is peste des petites ruminants (PPR), which is highly contagious and lethal among sheep and goats. Related to the rinderpest virus, the PPR virus has long circulated in central Africa, the Middle East, and the Indian subcontinent and has recently spread to Morocco. Jan Slingenbergh, an FAO infectious diseases specialist, is cautious. PPR isn't as devastating as rinderpest once was, he says, and available vaccines are not as effective as the rinderpest vaccines, so disrupting viral transmission would be even harder. Slingenbergh says FAO will attempt progressive control of PPR, starting in priority areas and expanding as studies indicate the best way forward. But the focus will be on “a package of small ruminant health care rather than singling out one disease,” he says.

One of the final steps of the rinderpesteradication program is tracing virus samples held in labs around the world and then sequestering them in a small number of secure international depositories, says Roeder. The GREP secretariat will continue to watch for the disease, he says, noting that he personally monitors disease outbreak Web sites and international news for any hint of a rinderpest revival. Rinderpest might be gone, but it's not forgotten.

5. China Census

# 1.3 Billion Divided by 6.5 Million, and Watch That Floating Decimal

1. Mara Hvistendahl*

Taking an accurate tally in the world's most populous and mobile country is already a formidable task. But when 6.5 million census takers fan out across China on 1 November, they will face an additional challenge: getting a handle on a swelling migrant, or “floating,” population. The Chinese government has put “a lot of attention on enumerating the floating population as accurately as possible,” says Duan Chengrong, a demographer at Beijing's Renmin University who helped design the sixth national census. China's unique solution this year—adding presumed residents to an actual head count—unsettles some demographers.

In the 2000 census, enumerators identified people using household registration records. Migrants had to have lived in a city for 6 months to be counted, a requirement that made it easy for census takers to miss recent arrivals. The result was an unprecedented rate of undercounting attached to China's official tally. China's last population figure of 1.3 billion includes 22.5 million Chinese thought to have been missed in the 2000 count. Many countries adjust results to account for underreporting and other statistical inconsistencies; on that score, China is not alone.

This year, to reduce undercounting, census takers will bolster registration records with a partial head count, using digital maps to pinpoint homes in far-flung or unlikely areas. “With geographic information systems, we can see clearly which houses are in which census districts,” says Li Xiru, who is overseeing the technology's introduction for the National Bureau of Statistics, which administers the census. The 6-month residency rule still applies for floaters, Li says, but enumerators will try to tally recent migrants in their villages by asking families about absent members. Foreigners and residents of Hong Kong and Macao will be counted for the first time.

An approach that combines registration data with a head count and detailed interviews is “unique in the world,” says Zhongdong Ma, a demographer at Hong Kong University of Science and Technology. The compromise acknowledges that household registration information is increasingly irrelevant. In recent decades, over 100 million rural residents have flooded China's cities in search of work. Many middle-class Chinese, meanwhile, have fled to the suburbs while maintaining apartments and residence permits in the city.

The novelty of this year's census worries observers like Qiao Xiaochun, a demographer at Peking University's Institute of Population Research. After working as a census officer in 1982, he published a book proposing that China switch to a de facto count, in which everyone is tallied in the districts where they are found on census day, regardless of registration. This year's change is a step in the right direction, he says, but it opens alarming loopholes. People “may be enumerated twice,” Qiao says. “Or they may not be enumerated at all.”

Accuracy will depend on the enumerators, mostly short-term workers recruited in the past few months who will disperse throughout China over 10 days. They will help respondents fill out a form listing 15 questions—more than ever before. A randomly selected 10% of Chinese will complete a long form that asks about things like education, housing, and marital status. The government is “going to great lengths to make a really detailed record,” says Kam Wing Chan, a geographer at the University of Washington, Seattle, who studies migration in China. But that thoroughness, he says, has drawbacks: More questions could reduce the response rate.

In 1982, when China introduced modern census-taking techniques, many Chinese lived in closely monitored work units. Today people are busier, more mobile, and more private. Everyone from unmarried couples worried about disapproving neighbors to tax-evading tycoons may have reason to dread the enumerators.

In recent months, a barrage of propaganda has assured wary Chinese that information will be used only for calculating population data—and reminded them that the census is essential for planning schools, nursing homes, and transportation networks. But some local authorities implementing the count have already reneged on the promise to safeguard individual rights. During a census rehearsal in Beijing last August, plainclothes police posing as enumerators detained dissident writer Xie Chaoping.

Other problems are disappearing with economic development. In 2000, some couples who had babies outside the one-child policy did not report those births, and as many as a quarter of young children went uncounted. Surveys suggest that the number of second and third births has fallen since then, so today's parents have fewer children to hide.

Along with the total population, scholars look forward to an updated sex ratio at birth—a 2005 sample survey found that 120.5 boys were born for every 100 girls, the most skewed ratio in the world—along with new fertility and mortality rates. The U.S. Census Bureau will use those numbers to revise its estimate for when China's population will peak, says Daniel Goodkind, a demographer at the bureau. The current forecast is 2026.

Beyond those broader tabulations, demographers wonder how much they'll learn. The Chinese government does not publish detailed data that allows demographers to make sense of its census tweaks. “How the census is adjusted is not known,” says Cai Yong, a demographer at the University of North Carolina, Chapel Hill. China's biggest tweak yet—counting absentee residents—should only increase the uncertainty.

• * Mara Hvistendahl is a journalist based in the Netherlands.

6. ScienceNOW.org

# From Science's Online Daily News Site

Caribbean Coral Die-Off Scientists studying Caribbean reefs say that 2010 may be the worst year ever for coral death there.

Bleaching occurs when crucial microorganisms leave coral reefs during stress, such as prolonged warming. For example, in 2005, water temperatures off the Virgin Islands rose just 3°C above the average in August but stayed that way until November, bleaching 80% and killing up to 40% of corals on the eastern side of the Caribbean.

Now temperature maps produced by the U.S. National Oceanic and Atmospheric Administration indicate that, since reaching abnormally high temperatures in June, the water has remained hot for longer than in the 2005 episode. And the warming has affected a much broader area of the western and southern Caribbean, devastating reefs in the Netherlands Antilles and off the coast of Panama. Although some wind has mixed and cooled the waters, researchers in the area say the bleaching is worse than they've seen before, affecting hard corals, sponges, and sea anemones.

'Dance Your Ph.D.' Winner Announced What kind of science makes the best dance? The overall winner of the 2010 “Dance Your Ph.D.” contest has proven that it just might be chemistry. On 18 October, at the Imagine Science Film Festival in New York City, a judging panel announced that Ph.D. student Maureen McKeague's dance interpretation of her research on designer molecules had beat out the best Ph.D. dances from physics, biology, and the social sciences. McKeague was also the winner of Science's online reader poll.

Just like her research, “this was a group effort that involved our whole lab,” says McKeague, who attends Carleton University in Ottawa, Canada. She went home with a $1000 prize from Science, which sponsored the contest. Politicians, Watch Your Grammar As congressional midterm elections approach in the United States, politicians are touting their credentials, likeability, and policy ideas. But they may be forgetting something crucial: grammar. Psychologists Teenie Matlock of the University of California, Merced, and Caitlin Fausey of Indiana University, Bloomington, asked 188 university students to read sentences about hypothetical politicians. Half saw statements like, “Last year, Mark was having an affair with his assistant and was taking hush money from a prominent constituent.” The other half saw this: “Last year, Mark had an affair with his assistant and took hush money from a prominent constituent.” The difference is one of grammatical aspect: “was having” and “was taking” are known as the imperfect aspect, meaning an event may be continuing. But “had” and “took” are known as the perfect aspect, meaning the event is bounded in time. The subtle differences had a strong impact: More than three-quarters of students who read the imperfect aspect phrases said they were confident that the politician would not be reelected, whereas only about half who read the perfect aspect phrases felt this way, the researchers report in Political Psychology. In both cases, the perfect aspect—“had an affair”—conveys a sense that the bad deed is in the past, says Matlock. That may make voters more likely to forgive these actions. On the other hand, imperfect phrases such as “was having an affair” suggest that the bad deeds may still be happening and are more relevant to an upcoming election—and hence, that the politician is less electable. Stormy Distant Sun The planets orbiting Iota Horologii (inset) enjoy only brief respites from their tempestuous sun. The star, located 56 light-years away in the southern constellation Horologium, boasts the shortest starspot cycle ever seen: 1.6 years. The sunspot cycle of our own sun (main image), by contrast, waxes and wanes every 11 years. When sunspot numbers peak, the sun can hurl satellite-frying flares toward Earth. So any residents of the Iota Horologii system—which bears at least one giant planet—presumably experience more frequent outbursts, lead author Travis Metcalfe of the U.S. National Center for Atmospheric Research and colleagues will report in an upcoming issue of The Astrophysical Journal Letters. Similar conditions may have confronted Earth as life was struggling to establish itself. At that time, the sun likely resembled Iota Horologii, because the star is young. Read the full postings, comments, and more at http://news.sciencemag.org/sciencenow. 7. Newsmaker Interview: Hamid Ahmed and Samir Raouf # Iraq Banks on Peer Review to Rebuild Its Research Base 1. Yudhijit Bhattacharjee In 2004, a year after the United States and its allies invaded Iraq and overthrew Saddam Hussein, the Coalition Provisional Authority created the Iraqi Nonproliferation Programs Foundation. Although it was supposed to evolve into an agency to fund basic and applied research, its$47 million allocation never materialized after the new Iraqi government came to power.

Today, only 14 months before the final pullout of all U.S. troops, Iraqi officials are still trying to build a research infrastructure. As part of that effort, a six-member Iraqi delegation visited the United States recently to study the U.S. system. They met with officials at the National Science Foundation, the National Institutes of Health, and the White House Office of Science and Technology Policy and traveled around the country to meet with nongovernmental organizations and universities.

The group's mission is to recommend a science-policy apparatus for the country, once a regional scientific power, that would rest upon a merit-based competitive process of awarding grants. Such a system would replace what Alex Dehgan of the U.S. Agency for International Development in Washington, D.C., calls the primary funding mechanism under the Ba'ath Party dictatorship, “a wave of Saddam's hand.”

Last week, Science spoke to two leaders of the delegation: Samir Raouf, an electrical engineer who is Iraq's senior deputy minister for science and technology, and Hamid Ahmed, a physician-scientist who advises the prime minister on education and higher education. Their remarks have been edited for brevity and clarity.

Q:What was Iraqi science like under Saddam Hussein?

S.R.:Iraq was once a leader in science and technology among Arab countries. But after Saddam Hussein took power, research and development were almost entirely directed toward military activities; that was to be expected since we went through three wars during the 3 decades of his regime. The wars also had an impact on the economy, reducing the money allocated to research and to education. Also, the number of Iraqis getting postgraduate degrees from other countries fell to around zero in the second half of the 1980s, and that continued until 2003. That created a barrier between Iraqi science and the rest of the world, creating a kind of isolation that affected the quality and level of science in Iraq.

Q:What is the state of Iraqi science and education today?

H.A.:We're still in a transition period, but a lot of good work has been done. Since 2003, there has been a significant investment in higher education in science. Thousands of Iraqi students have been sent abroad on government scholarships.

S.R.:One of the first decisions was to establish a ministry of science and technology. Most of the organizations that were linked to scientific research and had people working on science and technology were organized under this ministry. But rebuilding science and technology is not an easy task; it will take time.

Q:Are there things the country must attend to before rebuilding science?

H.A.:Yes, security is a priority, and most of the government's efforts and funds are directed toward security. Second priority I would say is services. Because of the wars and sanctions, the infrastructure is devastated; electricity, water, health services are not yet up and running.

S.R.:But all these problems, … science and technology can play a role in solving them. Without science and technology, all the solutions to these problems will not be sustainable.

Q:What scientific institutions and agencies does Iraq need?

H.A.:We used to have a national scientific and research council, but the previous regime abolished that. Our mission is to help formulate a body that is responsible for drafting research policy (and funding research), be it within the ministry of science or, because it has wider application, in the ministry of higher education.

Q:Is there anything from the U.S. model that you plan to replicate?

S.R.:The first thing is to finance research through grants that researchers can apply for, irrespective of where they are working. We want to use peer-review and merit based processes; … this is essential to getting the best people to work on their specialty.

Q:Are there enough Iraqi scientists to have a robust peer-review system?

H.A.:We have enough, … but if needed, we have thousands of Iraqi expats around the world that we can turn to.

Q:Are there particular areas of science that the government is emphasizing?

S.R.:We want to direct all science and research activities toward development. We have started decommissioning of nuclear facilities, and we are leading an initiative for e-governance in Iraq. Renewable energy is an important area because, although we have petroleum, we also have a sunny environment. Also, we want to focus on environmental research, because the neglect of the environment over the past 3 decades has had a big impact on all aspects of life in Iraq, from agriculture to health.

Q:Five years from now, can we expect to see something like an Iraqi National Science Foundation?

S.R.:Inshallah [God willing].

H.A.:We hope so.

8. Archaeology

# Reanalysis of French Cave Could Deal Setback to Neandertal Smarts

1. Michael Balter

Neandertals have been on a roll in recent years. Once regarded as brutish and dumb compared to modern humans, our closest cousins are now often credited with “modern behaviors” such as crafting sophisticated tools and symbolic personal ornaments (Science, 15 January, p. 255). But new radiocarbon dating at a celebrated site in France could mar this flattering view of Neandertal capabilities. The study, published online this week in the Proceedings of the National Academy of Sciences, concludes that jewelry and tools once attributed to Neandertals may be the work of modern humans. “This key site should be disqualified from the debate over [Neandertal] symbolism,” says archaeologist Randall White of New York University, who was not involved in the work. But archaeologist João Zilhão of the University of Bristol in the United Kingdom says that the new study “prove[s] the exact opposite of what [its] authors claim.”

The Grotte du Renne (“reindeer cave”) at Arcy-sur-Cure in central France was excavated between 1949 and 1963 by the late French prehistorian André Leroi-Gourhan, who found 15 archaeological levels. Leroi-Gourhan attributed artifacts in the lowest levels to Neandertals and artifacts from higher levels to modern humans, and later scholars have supported this interpretation. But the middle layers included bone tools, ivory ornaments, and other sophisticated artifacts that Leroi-Gourhan attributed to a culture called the Châtelperronian, which many researchers think was the work of Neandertals. Indeed, Leroi-Gourhan found about 30 Neandertal teeth in the Châtelperronian levels.

Most debates about the Châtelperronian—which began about when modern humans showed up in Europe, 40,000 years ago—have revolved around whether Neandertals developed the culture independently or simply copied the behavior of incoming modern humans. But recently, some researchers have questioned whether Neandertals made the Châtelperronian artifacts at all.

In the new study, a team led by dating expert Thomas Higham of the University of Oxford in the United Kingdom reports 31 new radiocarbon dates from the Grotte du Renne using novel methods designed to avoid contamination. The dates, obtained on materials such as bone tools and ornaments made of animal teeth, paint a disturbing picture: While upper layers attributed to modern humans clock in at no older than 35,000 years, artifacts from the Châtelperronian levels range from 21,000 years old, when Neandertals were long extinct, to 49,000 years old, before the Châtelperronian began. About one-third of the dates were outside the expected range.

The team concludes that the archaeological layers must have become mixed over thousands of years, raising the possibility that younger artifacts made by modern humans moved down into lower levels. “The evidence from the Grotte du Renne ought to be viewed with extreme caution,” the authors write. White agrees, pointing out that only one other undisputed Châtelperronian site has produced personal ornaments, and in much smaller numbers, thus leaving the case for Neandertal symbolism on shaky ground.

Zilhão counters that two-thirds of the dates at the Grotte du Renne do fall within the Châtelperronian period and that the outliers could be due to contamination. But Higham, who has been redating nearly 20 other Neandertal and modern human sites in Europe, says the Grotte du Renne is unique in producing such wildly varying dates. “I think this is telling us something,” he says.

9. ScienceInsider

# From the Science Policy Blog

The presence of protesters last week at an agribiotech symposium at Huazhong Agricultural University led to an impromptu session between members of the general public and scientists that revealed the public's deep distrust of—and confusion about—genetically modified crops.

President Barack Obama has kept a promise by honoring dozens of students for their achievements in science competitions around the country. The White House event was part of a national science and engineering festival.

The nations that make up the Intergovernmental Panel on Climate Change have made some changes aimed at improving how the organization responds to critics, deals with scientific uncertainty, and handles its day-to-day affairs.

The Nuclear Regulatory Commission is playing politics with the fate of a technical study of the Yucca Mountain nuclear waste repository, say congressional Republicans, who add that the Obama Administration's attempt to end the project preempts federal legislation.

U.S. National Cancer Institute Director Harold Varmus wants cancer researchers to chew on some “provocative questions” as the first step in tweaking the research agenda for the $5 billion NIH agency. Food production will need to double worldwide to meet the needs of a growing population. But a new report says productivity will need to increase even faster to avoid causing greater environmental damage to the planet. The U.S. national medals of science and technology, a research prize for understanding violence in children, and a new science-writing award were announced last week. For more science policy news, visit http://news.sciencemag.org/scienceinsider. 10. # Immune Therapy Steps Up the Attack 1. Jennifer Couzin-Frankel BETHESDA, MARYLAND—On a corner of Steven Rosenberg's desk rests a small, gold figurine representing Sisyphus, its arms straining to push a boulder forward. A gift from his wife when he joined the U.S. National Cancer Institute (NCI) here as chief of surgery back in 1974, it is uncannily apt: Rosenberg has spent 3 decades rolling metaphorical boulders uphill, only to see them tumble back down again. Rosenberg's specialty is immunotherapy; he tries to harness a patient's own immune system to fight cancer. He and others have seen remnants of immune system attacks on tumors, but the cancer recovers and takes off. Efforts to lend the immune system a hand have raised hopes, leading to large clinical trials of cancer vaccines. But all have flopped. And year after year, nearly all of Rosenberg's patients, recipients of radical experimental treatments, succumbed to their cancer. Nearly all, that is, until recently. Slowly, new immune-based therapies are registering successes. In some people riddled with the aggressive skin cancer melanoma, immunotherapy has not only eliminated disease but also kept it at bay for years. Such outcomes are virtually unheard of in patients with metastatic disease that has spread through the body. Last month, NCI awarded$14 million to the Fred Hutchinson Cancer Research Center in Seattle, Washington, so it could launch a new national network of immunotherapy clinical trials.

From a patient's perspective, the achievements are still tenuous. Some individuals respond dramatically. But only a fraction are treated successfully—about 15% at most, though some small trials have hints of higher numbers. What excites immunotherapists is that this modest group of responders—the “tail end of the curve”—keeps showing up in recent studies. This year, it appeared in trials of two antibodies used against several different cancers, and in data from Rosenberg's cell therapy recently published or presented at meetings. With more tinkering, cancer specialists hope to shift additional patients into the responder category and devise more powerful combination treatments. Accustomed to disappointment, they have rarely been so confident.

At the same time, their successes are raising deep questions about where cancer therapy is headed. Integrating immunotherapy into clinical care will pose challenges of its own. Patients may take months to respond, making it difficult to assess whether treatment is helping. Furthermore, some treatments are highly personalized and impossible to administer outside of specialized settings. This makes them extraordinarily expensive. Many specialists wonder whether they can really become part of standard cancer care.

Rosenberg is a believer. “The goal right now is to find things that work,” he says. “When you find things that work, industry finds ways to make it happen.”

## Rocky start

One patient has never left Rosenberg's thoughts. As a junior resident in a Boston hospital in 1968, Rosenberg met James DeAngelo, then in his 60s, who had been admitted for gallbladder surgery. Twelve years earlier, DeAngelo had developed a stomach cancer that spread to his liver and was sent home to die. Instead, his cancer spontaneously regressed without treatment—“one of the rarest events in all of medicine,” Rosenberg says now.

One of Rosenberg's first surgery cases became part of an experiment. At the time, Rosenberg recalls, “there was someone else in the hospital who had gastric cancer” and whose blood type matched DeAngelo's. Following the wild theory that something in DeAngelo's blood could help this desperately ill man, Rosenberg transfused blood from DeAngelo into the second patient. Nothing happened, and that man later died of his cancer.

But Rosenberg couldn't shake the memory of that gallbladder surgery, where he ran his hands across DeAngelo's liver and found no hint of disease. Had DeAngelo's body fought off cancer on its own?

In some ways, the notion didn't make sense. Cancer cells are a patient's own, so why would the body perceive them as invaders? The answers are now clear. Among them: Tumor cells are genetically unstable and pile on new mutations that render them distinct from the host. In 2007, oncologist Bert Vogelstein of Johns Hopkins University in Baltimore, Maryland, and his colleagues reported in Science that breast and colon cancers can harbor hundreds of gene mutations—an “unexpectedly high number,” says Suzanne Topalian, a Johns Hopkins melanoma specialist who was not involved in the work. And those mutations “should be recognized by the immune system,” she says. Studies have confirmed it: Tumor cells often display antigens not found elsewhere in the body that prompt immune reactions.

Immunotherapists targeted melanoma because primary melanoma tumors—as opposed to metastatic ones—are among the few that can spontaneously disappear. Doctors also identified antibodies to melanoma in the blood of patients and a higher incidence of the cancer in those who'd received organ transplants and had suppressed immunity. All of these clues suggested that the immune system engaged in an elaborate dance with the disease.

Given that roughly 8 million people around the world will die of cancer this year, it's clear that the immune system alone is no match for cancer's wiles. Robert Schreiber of Washington University School of Medicine in St. Louis, Missouri, advanced a framework in 2001 that's often cited to explain why. Schreiber argued that the immune system does go after the tumor initially: He called it the elimination phase. This may destroy many cancers before they're detected. But he argued that other tumors develop an immunosuppressive barrier, expressing proteins on their surface that dampen immune attacks. In this equilibrium phase, the tumor and the person with cancer coexist. At some point, the cancer slips into the escape phase, where the balance tips in its favor.

In the past 2 decades, dozens of therapies have tried to stimulate the immune system against cancer, including about 20 vaccines that reached mid- and late-stage clinical trials. “We've been excited by every single one of these,” says Mario Sznol, an oncologist at the Yale School of Medicine who focuses on melanoma and kidney cancer. But, he concedes, “for the most part, none of those things really did much.”

Because tumors evolve to prevent the body from recognizing them as foreign, vaccines need to trigger a massive immune response. Most cancer vaccines just haven't been potent enough, says Jeffrey Weber, a melanoma specialist at the H. Lee Moffitt Cancer Center and Research Institute in Tampa, Florida: “We've been giving very wimpy immunizations, in my view.” They may have been ineffective for another reason: Researchers had only a rudimentary understanding of how the immune system and tumors interact. Slowly, that is changing.

## Antibody breakthroughs

“The science is now guiding the medicine,” says Jedd Wolchok, a melanoma specialist at Memorial Sloan-Kettering Cancer Center in New York City. “The paths that we are taking are built upon a much more solid understanding of what is going on molecularly.”

Empowering T cells is a key part of the new strategy. One breakthrough came in 1996, when Wolchok's colleague James Allison reported in Science that a protein called CTLA-4 makes T cells less active (22 March 1996, p. 1734). In mice, Allison found that blocking CTLA-4 with an antibody killed tumors. A biotechnology company called Medarex picked up anti-CTLA-4, which now goes by the generic name ipilimumab, in hopes of turning it into a cancer therapy. Wolchok, Rosenberg, and others began testing it in people.

In a small number of patients, the results were dramatic. “I do remember those early days; we were looking at CT scans and saying, ‘Oh my goodness, this thing's really working,’” says Topalian. In the summer of 2009, the pharmaceutical giant Bristol-Myers Squibb purchased Medarex for $2.4 billion, gaining rights to both antibodies. In August 2010, the company and its academic collaborators reported on the phase III results of an ipilimumab trial with 676 melanoma patients. For the first time ever, a randomized trial found that people with stage 4 melanoma benefited from a new treatment. The advantage was modest: Treated patients survived 10 months, on average, compared with 6.4 months for controls. “What is exciting is when you look at the tail of the curve,” says Allison. “Very few patients survive more than 2 years with metastatic melanoma,” and in this trial, just under a quarter of those treated did. Many still have tumors, however, but their disease is stable and they don't need treatment, says Allison. Only three out of the 540 who received the therapy were free of cancer altogether. Just as chemotherapy comes with risks, so does ipilimumab. Side effects included severe diarrhea, colitis, and endocrine disruption; 14 patients died from the treatment. Still, researchers believe that ipilimumab will gain approval from the U.S. Food and Drug Administration (FDA) in the coming months. Medarex had also been working on another naturally occurring protein called PD-1 that dampens immune responses. Whereas mice without CTLA-4 die of immune defects, those without PD-1 are healthier, suggesting that an antibody against PD-1 could have fewer side effects. The response rate for anti-PD-1 looks hopeful. Results from a small trial published in July in the Journal of Clinical Oncology and additional data presented at a cancer meeting in June suggest that about one-third of melanoma and kidney cancer patients responded—that is, their tumors shrank. “The most amazing thing of all,” says Drew Pardoll of Johns Hopkins, who has been involved in the development of anti-PD-1, is that up to 3 years after treatment, “not a single responder has yet relapsed. … That's eye-popping.” Many of them still harbor tumors, but “they're just sitting there” and not growing, says Pardoll. Both antibodies are being tested in other cancers. Responses to ipilimumab have shown up in ovarian, prostate, and lung cancer, in addition to melanoma, says Allison. In theory, if a patient's T cells are reacting to tumor antigens, this approach “can be used for any kind of cancer.” ## Narrow success Antibodies like ipilimumab are valuable, Rosenberg says, but in his mind, they're not nearly enough. If the cancer doesn't completely disappear, “everybody dies” eventually, he says. Rosenberg wants a cure, and he is willing to go to great lengths to get it. He's testing a different approach at the National Institutes of Health (NIH) Clinical Center here, which draws people from all over who are running out of options and treats them free of charge. Rosenberg estimates his budget for immunotherapy at about$3 million a year, far higher than virtually anywhere else.

On this day he drops in on a cheerful woman in her mid-40s with reddish-brown hair and chunky black glasses. She will be the first person to receive Rosenberg's immunotherapy for colorectal cancer. If it fails, he guesses she has between 4 and 6 months to live.

Unlike antibody therapy, which is administered intravenously in an outpatient setting, Rosenberg's method requires hospitalization and a research clinic, at least for now. He focuses on finding T cells activated to attack cancer, usually in tumor tissue. His goal is to extract these T cells, grow them into the tens of billions outside the body over several weeks, and give them back. To make this work, Rosenberg discovered several years ago that he first needs to destroy a patient's existing immune cells with high doses of chemotherapy and sometimes total-body irradiation.

Rosenberg's approach is not an option for many patients. T cells can't be harvested from those with inaccessible tumors, about one-fifth of melanoma patients. For another fifth, the cells don't grow well outside the body. Many can't wait the month it takes to expand cells in the lab. And the pretreatment chemotherapy, as well as a drug given during treatment, is so toxic that most people over 70 can't tolerate it.

But for those lucky enough to have that precious bag of T cells returned to them, the likelihood of success is impressive. Out of 93 patients with metastatic melanoma who have received the treatment and been followed long-term, 20 saw their cancer disappear completely. Nineteen have remained cancer-free for 3 to 8 years. In another 32, tumors shrank. Nearly all of these patients had failed every available therapy, including, in many cases, ipilimumab.

In his office, Rosenberg clicks through a series of CT scans on his computer screen from one of his success stories, a police officer coming in for a follow-up visit. Like most of Rosenberg's patients, the policeman had metastatic melanoma. Although suffering long-term effects from radiation he received when Rosenberg treated him, he's been free of cancer since T-cell therapy 4 years ago.

Rosenberg is now trying to get around one big limitation of his strategy: the need for tumor tissue as a source of T cells. He's experimenting with removing T cells directly from the blood of patients and genetically engineering them to recognize antigens on tumors. This would potentially open up the therapy to people with all sorts of cancers, especially those with hard-to-reach tumors that can't be surgically removed for the T-cell hunt. Rosenberg is also beginning to extend his therapy to lymphoma and sarcoma as well as colon cancer. So far, the few patients treated are doing well.

Several large academic medical centers in Seattle, Houston, and elsewhere have also been working on refining the therapy, called adoptive T cell transfer (ACT). All report roughly comparable success rates, but none is doing as much as Rosenberg at NCI—largely, they say, because of the cost.

Although the results are compelling, ACT “is 100 times as hard to export, to do in a reproducible fashion, and it's also a lot more expensive than” antibodies, says Pardoll. “Companies essentially have no interest in it. It really right now is a purely academic exercise.”

ACT has taught us a great deal, says Wolchok at Sloan-Kettering—for example, that people with heavy cancer burdens can be helped just by expanding and reintroducing their T cells. But ACT faces daunting hurdles in “being able to produce the cell product for every patient who needs it,” he says. Even in Rosenberg's lab, the cells don't always grow, says Wolchok, who has referred patients to the program. Sznol at Yale has looked into setting up an ACT program there, but the logistics have made it too difficult to pull off yet.

Although Rosenberg agrees that companies haven't invested in ACT, he is frustrated by those who critique its practicality. He has a lab member working full-time with NIH's blood bank to determine whether it can grow patients' cells more efficiently. NCI recently began a randomized clinical trial of ACT in melanoma. The hope is that if ACT proves superior, payers might cover its cost, which depends on the protocol but can exceed $100,000 per patient. Even doubters recognize that what's dismissed as impossible in medicine is always changing. “Monoclonal antibodies had the same stones thrown at them 20 years ago,” with everyone questioning their feasibility, says Wolchok. With ACT, “it may just be time for the technology to catch up with the need.” After much hesitation, pharmaceutical companies have expressed growing enthusiasm for cancer immunotherapy. In April, FDA approved the first cancer vaccine, called Provenge, for metastatic prostate cancer, made by the company Dendreon in Seattle. Treatment consists of three infusions for a total cost of$93,000. Many oncologists are underwhelmed by its effectiveness. The vaccine extends survival by 4 months; it does not stop cancer. But just the fact that Dendreon pushed ahead with the vaccine, which is custom-made for every patient, is heartening to some immunotherapists.

Bristol-Myers Squibb has its antibodies—ipilimumab and anti-PD-1—while another pharma giant, GlaxoSmithKline (GSK), is running several large trials of a new cancer vaccine for lung cancer and melanoma. Unlike Provenge, the GSK vaccine is an off-the-shelf mix. It includes an antigen, MAGEA3, that commonly appears on cancer cells, and an adjuvant to boost immune reactions; introduced together, these aim to stimulate the immune system to go after cells expressing MAGE-A3. GSK is trying to use gene profiling of tumors to carefully pick patients most likely to respond. “We do not want to have the clinical efficacy diluted because we don't select the right patients,” says Vincent Brichard, head of immunotherapeutics at GSK Biologics in Rixensart, Belgium. “This could explain why previous trials have failed.”

## Skill and subtlety

As immunotherapy edges into the clinic, it's likely to challenge oncologists' expertise. When chemotherapy works, it works quickly; immunotherapy is very different. “You might not see responses right away, and they may get worse before they get better,” says Cassian Yee of the Fred Hutchinson Cancer Research Center. “It does take a little bit of insight for the person managing the patient to say, ‘OK, your tumor's only grown by 10%, 20%—we think that you should continue” on ipilimumab.

No one yet knows why tumors might grow before they dissipate. Indeed, there's still much that remains a mystery about how antibodies and ACT behave in the body, how to predict who they'll help, and how to make them more effective.

A subset of patients might have what Thomas Gajewski of the University of Chicago in Illinois calls the “inflamed phenotype”: They are capable of “making some smoldering immune response against their tumor that you can tip over” in their favor, shrinking the cancer or erasing it altogether. Gajewski estimates that at least 30% of patients fall into this category. He's looking for ways to coax the other 70% to respond: “How do you make the noninflamed tumors inflamed?” he wonders.

Most cancer specialists believe the solution will come from combination therapies. Like Gajewski, Allison theorizes that immunotherapy is most effective when an immune response is already under way, with T cells activated and tumor cells dying. One way to tip more patients into this category might be by supplementing immunotherapy with direct killing of tumor cells. Bristol-Myers Squibb is running a large prostate cancer trial that combines ipilimumab with a single dose of radiation to do just that. In theory, the antibody might also enhance the potency of T cells given in ACT, says Yee.

Which treatments will go mainstream? “Everybody's goals are the same: Let's try to cure cancer patients,” says Rosenberg. But is it reasonable to set up expensive cell growth facilities, as some want NCI to do, especially if they'll help only a subset of patients? And who will pay? With immunotherapy, no matter which approach you take, says Yee, “you're going to start off with high expenses.” The hope is that long term, the payoff will be worth it.

11. Astronomy

# Radio Astronomers Take Arms Against a Sea of Signals

1. Yudhijit Bhattacharjee

The valley around the 100-meter-wide Green Bank Telescope (GBT) in West Virginia is one of the most radio-hostile places on Earth. Transmissions from cell phone towers, broadcast stations, and other devices that could interfere with the telescope's observations of the cosmos are unwelcome here. Two lines of defense shelter GBT (pictured above) and other telescopes that the National Radio Astronomy Observatory (NRAO) operates in Green Bank. First, the Appalachian Mountains block radio transmissions from towers to the southwest. Second, in 1958, the U.S. Congress designated a 34,000-square-kilometer expanse around Green Bank as a National Radio Quiet Zone (NRQZ). Transmitters that could cause radio interference for telescopes at Green Bank are forbidden by law. Cell phones don't work here.

But this haven for radio astronomers is under attack. Over the past decade, Green Bank has faced increasing interference from mobile wireless devices, including Wi-Fi modems and Bluetooth, satellite radio channels like XM and Sirius, global positioning systems, and other radio sources not covered by the 1958 law. Last year, the switch to all-digital television broadcasting in the United States—a bigger cause of interference than analog signals—added to Green Bank's troubles. Meanwhile, traditional sources of interference such as airplanes and satellites continue their barrage.

Intrusive emissions routinely contaminate data from cosmic radio sources, leaving astronomers to sort through the confusion. In the worst instances, the interfering signals can be strong enough to wipe out several hours of observation in a single stroke, as NRAO astronomer Scott Ransom learned 5 years ago while using GBT to look for pulsars. All of the data from a full night of observing were ruined by what turned out to be a strong Wi-Fi signal from a house nearby. Skiing on Snowshoe Mountain the next day, Ransom found out that the house belonged to the friend he was skiing with: an NRAO engineer who had illicitly installed a wireless modem at home. “He looked very sheepish,” Ransom says.

The noise problem at NRQZ is shared by radio telescopes around the world, most of which lack Green Bank's protections. Unfortunately, the more sensitive radio telescopes become to detecting weak signals from space, the more vulnerable they are to humanmade interference. “We're seeing an exponentially growing use of mobile and other wireless devices, even in the relatively desolate areas where most radio telescopes are located,” says Andrew Clegg, an official with the U.S. National Science Foundation in Arlington, Virginia, who works to promote the use of the radio spectrum for science. The resulting competition for spectrum, Clegg says, has developed into a significant challenge for radio astronomy.

Astronomers have been developing a slew of solutions to meet that challenge. They include electronics that help radio receivers tolerate data-threatening power surges, filters to avoid frequencies at which interference is likely to occur, and ways of making telescopes and telescope arrays selectively blind to signals coming from certain directions in the sky to cancel out interference from satellites and airplanes.

In addition, astronomers and radio engineers are coming up with new and improved techniques for subtracting interference from data after it has been collected. And observers at Green Bank and elsewhere are also working out human solutions: negotiating with local communities to reduce interference and silence it altogether for short durations to allow key observations.

## Lines of defense

The technical fixes start in a telescope's amplifiers. Because radio signals arriving at a telescope's antennae from a cosmic source are usually quite faint, they must be amplified several-fold before they can be processed. For the data to be usable, the amplification needs to be linear—that is, it must multiply the input signal by some constant factor. However, every amplifier has an upper limit beyond which an incoming signal no longer produces linear output. A strong enough interfering signal can ratchet the input past that upper limit. “If the amplification is no longer linear, then all of your data goes bad,” explains Bob Hayward, an NRAO engineer.

To guard against such spikes, researchers have been developing amplifiers with higher upper limits, or greater “headroom.” New telescopes such as the Low Frequency Array (LOFAR)—a network of 25,000 antennae headquartered in the Netherlands and spread across Europe—have been equipped with wide-range digital amplifiers; older telescopes have also been upgrading their electronics against interference.

Once the data have been protected, astronomers must detect and weed out the interfering signal. Traditionally, astronomers had to do much of this manually, painstakingly inspecting the data for anomalous spikes and deleting those portions. Increasingly, that task is being handled automatically and with greater precision.

A lot of interference is transient, such as a burst of emission from an aircraft flying overhead, explains Ger de Bruyn, an astronomer at the National Institute of Radio Astronomy in the Netherlands, which manages LOFAR. The latest digital electronics enable LOFAR's antennae to collect data with very high time resolution—across windows of time that are as short as nanoseconds. This allows LOFAR to remove with great precision those bits of data where interference has occurred, in effect preserving a much bigger percentage of the observed time than would have been possible in the past. “We have the potential to work down to 5 nanoseconds,” de Bruyn says.

There have also been steady improvements in software designed to spot interference, led by groups such as one headed by Dale Gary, an astrophysicist at the New Jersey Institute of Technology in Newark. “The thing we're taking advantage of is the statistical nature of the varying voltages coming out of the telescope,” Gary says. Voltages from cosmic radio sources, he explains, tend to form Gaussian distributions; those from earthly signals don't. Gary and his colleagues at Korea Astronomy and Space Science Institute have developed an interference-locating algorithm that quickly determines whether a stream of signals is Gaussian. It's being used at the Owens Valley Solar Array in California.

Other approaches take weeding out a step further: blocking out whole patches of the sky while continuing to observe the rest. Researchers led by Brian Jeffs, an electrical engineer at Brigham Young University in Provo, Utah, have developed a technique that uses an array of antennae to locate the direction of an interfering signal such as airplane or satellite transmissions. “Before the image is formed, we run the data through a processor that combines the signal from all of the antennas in a way that blocks out the interferer,” Jeffs says. The technique has been tried successfully on a 20-meter telescope at Green Bank; a similar technique is being implemented by LOFAR.

Another simple approach is to filter out interfering frequencies. For his observations of pulsars, NRAO's Scott Ransom has taken to using a filter that blocks frequencies between 2 and 2.2 GHz—the range of many wireless devices. “I certainly lose something as a result,” he says. “I could definitely get more sensitivity if I could use the entire band.”

## Eternal vigilance

Many radio observatories have spectrum managers whose job includes preempting the destructive effects of interference on their instruments. For example, when a NASA-funded satellite called CloudSat was scheduled for launch in 2005, managers at the Very Long Baseline Array (VLBA)—10 radio dishes laid out across about 8000 kilometers of the United States—flagged it as a threat. CloudSat was to use a frequency of 94 GHz; VLBA's receiver covered a range from 80 to 96 GHz. A couple of VLBA antennae pointing straight up at the sky—90 degrees from the ground—could have been fried by CloudSat's signals. “We changed those antennas to stow at 88 or 87 degrees, like the rest of the array, which precludes the satellite and the VLBA antenna looking straight at each other,” says R. Craig Walker, an astronomer with NRAO in Socorro, New Mexico, where VLBA is headquartered. The potential damage to VLBA from CloudSat had been averted, although astronomers would still have to weed out interference from the satellite's signals.

Where possible, observatory managers and astronomers have negotiated with nearby communities to reduce or silence interference. At the Giant Metrewave Radio Telescope in Pune, India, for example, administrators were able to get cell phone towers within 20 kilometers of the telescope to shift to a frequency that doesn't hinder GMRT's operations. Local officials have also agreed to help keep high-tension power lines free of stray wires, another pesky source of interference. At Green Bank, an Interference Protection Group led by Carla Beaudet has persuaded some local Wi-Fi users to switch to wired Internet connections by offering them free high-quality modems.

“Most people are excited about astronomy and are usually willing to help reduce their transmissions,” says Nissim Kanekar, an astronomer with NRAO in Socorro who has used GBT to study distant galaxies. Two years ago, Kanekar was scrutinizing a high-redshift galaxy for signs of a certain spectral line that would have helped him probe changes in fundamental constants such as the fine-structure constant over a long period of the universe's history. The problem was that the line was expected at 855 MHz, within a band of frequencies subject to interference by transmitters of American Electric Power (AEP) located just outside Green Bank's radio-quiet zone. Kanekar contacted AEP, which agreed to switch off transmitters to allow observations over weekend nights. When that didn't do the trick, the company obliged with more-extensive shutdowns. “I am still processing the data right now but am quite hopeful that we'll be able to see the line, which would be fantastic,” Kanekar says.

The wireless and satellite revolutions continue to throw up new challenges. NRAO's Harvey Liszt notes that automobiles with adaptive cruise control use powerful radar at 76 MHz to maintain a safe distance from other vehicles. “One of these cars could destroy a radio telescope,” says Liszt, who is thankful that the feature has not penetrated the market too far yet. Last year, after Toyota petitioned the Federal Communications Commission to allow higher power radars on cars, Liszt filed a comment alerting authorities to the threat to radio telescopes.

That's why makers of new radio telescopes like the Square Kilometre Array are drawn to remote, sparsely populated sites: places such as Western Australia and the Northern Cape province of South Africa, whose governments have promised to protect them from interference. Outside such radio-quiet oases, however, astronomers must continue to contend with satellites, cell phones, digital TV, and the rest of the 21st century's blaring conveniences.