New Scientist magazine - 10th January 2009

New Science Publications

Editorial–

Editor-in-Chief Jeremy Webb Editor Roger Highfield Associate Editors Liz Else, Stephanie Pain News Editor Shaoni Bhattacharya Editors Helen Knight, Celeste Biever, Richard Fisher, Sumit Paul-Choudhury, Priya Shetty Tel +44 (0) 20 7611 1206 Fax +44 (0) 20 7611 1250 Reporters LONDON Andy Coghlan, Paul Marks, Linda Geddes, David Shiga [email protected] BOSTON US Bureau Chief Ivan Semeniuk SAN FRANCISCO Bureau Chief Peter Aldhous [email protected] Jim Giles [email protected] TORONTO Alison Motluk BRUSSELS Debora MacKenzie MELBOURNE Australasian Editor Rachel Nowak [email protected] Features Editors Ben Crystall, Kate Douglas, Clare Wilson, David Cohen, Graham Lawton, Valerie Jamieson, Michael Le Page, Caroline Williams, Richard Webb Features Contacts Tel +44 (0) 20 7611 1201 Fax +44 (0) 20 7611 1280 [email protected] Opinion Editor Jo Marchant Editors John Hoyland, Amanda Gefter, Alison George, Eleanor Harris Tel +44 (0) 20 7611 1240 Fax +44 (0) 20 7611 1280 [email protected] Researcher Lucy Dodwell Editorial Assistant Amy Galloway Production Editor Mick O’Hare Asst Production Editor Melanie Green Chief Sub John Liebmann Subeditors Vivienne Greig, Julia Brown, Sean O’Neill, Eleanor Parsons Art Director Alison Lawn Design Craig Mackie, Ryan Wills Graphics Nigel Hawtin, Dave Johnston Pictures Adam Goff, Kirstin Jennings Tel +44 (0) 20 7611 1268 Fax +44 (0) 20 7611 1250

Allure of the technical fix Human ingenuity has its place – and its limitations AS Barack Obama’s new administration prepares to take power, we can but hope that 2009 will be the year the world gets serious about climate change. And not a moment too soon. Carbon emissions are growing faster than ever as the Earth’s natural ability to absorb them is declining. Species are starting to go extinct as a result (see page 14). It is a reflection of the parlous state of the planet that we report this week on technologies that not so long ago would have been dismissed as pie in the sky, even bonkers. Now they are increasingly seen as ways to repair the damage. On page 34 we examine the growing interest in technologies that scrub carbon dioxide out of the air. A few years ago the Intergovernmental Panel on Climate Change dismissed talk of such “artificial trees” as impractical. Now several teams have built prototypes, raising hopes that this approach might become economic.

Careers Editor Helen Thomson [email protected] Tel +44 (0) 20 7611 1248 Fax +44 (0) 20 7611 1280

One nuclear law for all

Consultants Alun Anderson, Anil Ananthaswamy, Stephen Battersby, Michael Bond, Michael Brooks, Marcus Chown, Rob Edwards, Richard Fifield, Barry Fox, Mick Hamer, Jeff Hecht, Bob Holmes, Justin Mullins, Fred Pearce, Helen Phillips, Ian Stewart, Gail Vines, Gabrielle Walker, Emma Young

AS WAR rages in the Middle East, it is scary to consider that one military power in the region already has nuclear weapons, another seems intent on getting them, and many others are planning to build their first nuclear power plants. How can we keep these plants from fuelling even more nuclear weapons? The revolutionary suggestion (see page 6) is to move the most proliferation-prone processes – fuel enrichment and reprocessing – from national to international control to ensure that fissile material is less likely to end up in nuclear bombs.

Press Office and Syndication UK Claire Bowles Tel +44 (0) 20 7611 1210 Fax 7611 1250 US Office Tel +1 617 386 2190 NEWSCIENTIST.COM Online Publisher John MacFarlane Online Editor Rowan Hooper Editors Maggie McKee, Tom Simonite Reporters Catherine Brahic, Colin Barras, Sandrine Ceurstemont, Michael Marshall, Ewen Callaway, Rachel Courtland Online Subeditor Dan Palmer Web team Neela Das, Cathy Tollet, Ruth Turner, Ken Wolf, Edin Hodzic, Vivienne Griffith, Rohan Creasey, Matteo Giaccone

Of course it is one thing to suggest that Iran, Egypt – and yes, Israel too – put their fuel cycle into international hands. But why should they when the nuclear haves such as the US, UK and Russia seem to have forgotten the promises they made under the Nuclear Non-Proliferation Treaty to give up their nuclear weapons? It makes perfect sense to put the riskiest nuclear industries under the most politically transparent and non-partisan of controls. For that to happen, though, the major nuclear powers must also start to abide by the rules. ●

Sorry, wrong number DEPENDING on how long you were stuck in meetings today, committees are either the ultimate expression of humanity’s ability to pool its talent, or its supremely timewasting invention. So it is welcome that, to find out which, mathematicians have revisited the pioneering work of British humorist C. Northcote Parkinson (see page 38). Their findings on the maximum size of

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There are also hints of a technological fix for species extinction. As our cover story explains (see page 24), it might be possible to resurrect extinct beasts such as sabre-tooth tigers or mammoths. Whether anyone would ever choose to do so is debatable, but the technology could also be used as a fallback to rescue species that are sliding towards extinction, such as gorillas, pandas or tigers. Both projects have huge superficial appeal in appearing to offer the possibility of atoning for our environmental sins without having to change our profligate ways. This is dangerous nonsense, of course. We must keep our focus on the primary causes of the planet’s problems. Neither technology is an adequate substitute for efforts to cut emissions, preserve habitats and conserve endangered species. They are, all the same, welcome reminders of what human ingenuity can achieve, and of the fact that there is only a fine line between schemes that are wild-eyed and those that are far-sighted. ●

an effective committee, for example, suggest that the European Union’s unwieldy membership of 27 is not helpful when it comes to making quick, decisive choices. And controversy is likely to be stirred by the news that the number 8 jeopardises group harmony. What does this mean for that influential clutch of nations, the G8? We need a new committee to investigate. ● 10 January 2009 | NewScientist | 3

News in perspective

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Upfront– YELLOWSTONE QUAKES UP What’s rumbling beneath Yellowstone? Hundreds of tremors have been rippling through the national park in Wyoming from late December to early January, prompting worries that the shaking may trigger dangerous steam explosions. The motion of magma and hot fluid permeating the rock beneath Yellowstone is thought to be responsible for the thousands of small earthquakes recorded in and around the park each year. These everyday quakes usually go unnoticed by people on the surface. Since 26 December, however, a much more powerful swarm of quakes has shaken the area. The strongest were easily felt by visitors and park staff, including one with a magnitude of 3.9. These were still too small to cause damage directly, but there were worries that the vibrations might cause pent-up steam to burst through the

surface with explosive force. Yellowstone is pockmarked with craters thought to have been produced in this way, and geologists estimate an explosion big enough to create a 100-metre-wide crater happens there every 200 years or so. Reassuringly, as New Scientist went to press, the quakes appeared to be subsiding. “It hasn’t stopped, but it’s reduced markedly in the last couple of days,” said Robert B. Smith of the University of Utah, Salt Lake City, on Monday. There are no signs of volcanic eruptions on the way either, says Smith, who monitors Yellowstone’s geological activity. The quakes appear to be concentrated along a fault beneath the park. Further analysis should reveal their cause, such as forces associated with the fault or the activity of hot fluids underground.

–Poised to let off some steam?–

Defending Ares WHY is NASA developing a new generation of space rockets when the US already has two that could do the same job? That’s one of the questions the transition team for the incoming Obama administration was reportedly asking NASA last week. At issue is the Ares series of rockets, currently being built to carry crew and supplies to the International Space Station, the moon and possibly Mars. These rockets have been plagued by questions over their design and cost, and are unlikely to be ready until 2015, leaving a gap in astronaut-launch capability if

“Rockets that loft satellites could be modified to launch astronauts” the space shuttle retires in 2010 as expected. The Ares programme looks likely to be reviewed by the new US administration. A possible alternative to Ares that was mooted last year and now appears to be facing fresh scrutiny would be to use Atlas V or Delta IV 4 | NewScientist | 10 January 2009

rockets to carry astronauts. These are mainly used by the US military to loft heavy satellites but could both be modified to become “human rated”. NASA has been here before. In 2006, the agency compared Ares to the Atlas and Delta heavy-lift rockets as candidate launchers. It concluded that many key Ares components have been adapted from the space shuttle, making it by far the safer option for crewed flights. For example, Ares’s first stage is a variant of the space shuttle’s solid-fuel rocket booster (SRB) – a design whose safety has been exhaustively scrutinised since the Challenger tragedy in 1986, when an SRB gas leak ignited the shuttle’s main fuel tank during launch. Ares’s second-stage liquid-fuelled engine doesn’t sit next to the SRB as on the space shuttle, so a failure in the SRB cannot ignite the liquid fuel – giving astronauts the chance to escape. “With Ares we are prioritising safety processes and systems for human spaceflight from the very beginning, rather than making an existing system suitable for people,” says a NASA spokeswoman.

Cheaper insulin? INSULIN grown in plants has been injected into people for the first time. The hope is that plants will provide a cheaper source of insulin for people with diabetes. Sembiosys Genetics, a Canadian company based in Calgary, Alberta, inserted human insulin genes into safflowers, causing them to make a compound called pro-insulin. Enzymes then converted this into a type of insulin called SBS-1000. Previous tests indicated that SBS-1000 is identical to human insulin, so last month Sembiosys

compared its effects with insulin from other sources in healthy volunteers. The company plans to release the results later this year. Most insulin products are produced by bacteria in a fermenter. As this is an expensive process, Sembiosys hopes using plants will be cheaper because they do not need this stage. Safflowers are not widely grown in North America, and have no wild relatives there. This should minimise the risk of genes escaping from insulin-producing safflowers grown there, says Maurice Maloney of Sembiosys.

DINO GRAVE SOLVES MYSTERY One of the world’s biggest dinosaur graves, in China, has yielded a key discovery: the 2-metre-long skull of a ceratopsid, a close relative of the triceratops. It is the first evidence that ceratopsids lived beyond North America. Since March 2008, over 7600 fossils have been found at the site in Zhucheng city, says Zhao Zijin at Beijing’s Institute of Vertebrate Paleontology and Paleoanthropology. The bones are thought to date from the Late Cretaceous.

Ceratopsids were four-legged rhinolike herbivores whose huge skulls bore horns and distinctive bony frills. Their remains had been found only in Alaska, western Canada, and the western US. Dinosaur hunters had been bamboozled that ceratopsids had apparently not ventured into Asia as tyrannosaurs did. “Eastern Asia and western North America had more similar biogeography than we thought,” says Tom Holtz of the University of Maryland in College Park.

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KATE DAVISON/EYEVINE

60 SECONDS

So low up high BLOOD oxygen in doctors climbing Everest plunged to the lowest levels ever recorded in a healthy human. This might mean some people in intensive care can tolerate lower oxygen levels than previously thought. The four doctors, who had spent weeks acclimatising to the

“You can see oxygen levels this low in people dying because they’ve had a cardiac arrest” thin air, took samples of their own blood at 8400 metres above sea level, 448 metres below the Everest summit. The average blood oxygen level was 3.28 kilopascals, with the lowest at 2.55 kPa (The New England Journal of Medicine, vol 360, p 140). The normal value is 12 to 14 kPa, while values below 8 kPa usually indicate critical illness. “You sometimes see levels this low in people who are dying because they’ve had a cardiac arrest,” says team member Mike Grocott of University College London. “We were able to talk, walk, take the blood gas and think clearly with these levels.” So some patients in intensive care might be able to tolerate lower oxygen levels, reducing the use of a ventilator which can damage the lungs. And people preparing to undergo surgery could perhaps be trained to cope better with low oxygen levels.

The Galapagos islands just keep on giving. Darwin’s thinking about evolution was powerfully shaped by his observations of how environmental factors caused the islands’ wildlife to form new species. But he ignored the pink iguana, which has now been found to be a different species to the other land iguanas. What’s more, it may be one of the earliest examples of species diversification on the islands.

The Milky weigh

Whale wars TENSIONS are rising in the Antarctic following skirmishes last month between anti-whaling protesters and Japanese vessels they accuse of commercial whaling under the guise of research. This week, Keiichi Nakajima, head of the Japan Whaling Association, called on the governments of Australia and New Zealand to close their ports to the Steve Irwin, a ship run by the Sea Shepherd Conservation

“We have engaged them and stopped their whaling activities for two weeks”

WANG XIAOQUANG/IMAGINE CHINA/AFP

Society, on the grounds that it has committed “criminal acts” and endangered lives. Failure to do so, he said, would make them “complicit” in any further attacks. Australia has agreed to consider Japan’s request. The Japanese Institute of Cetacean Research says that in the worst incident so far, the activists’ ship circled the Japanese whalesighting vessel for 3 hours on 26 December, before ramming it from behind and throwing bottles of acid at the ship and its crew. The protesters, however, deny this. “The extent of Sea Shepherd’s actions has been to toss rotten butter and slime onto the decks of –Unearthing delights– the whalers to hinder their illegal

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Not selected by Darwin

Our galaxy is much more massive than we thought. Measurements of the –For research or commercial gain?– motion of gas clouds, presented at a meeting of the American Astronomical activities,” says Paul Watson, the Society, reveal that the Milky Way is ship’s captain. “We have turned spinning faster than previously thought. their decks into stink holes but we This means that to hold everything have not hurt any whaler nor have together, our galaxy must have up to we damaged any property and we 50 per cent more mass than expected. have not rammed these illegal whaling ships.” Autism Brain Bank Now needing to refuel, the crew of the Steve Irwin say they The UK has launched its first bank of are determined to continue their donated brain tissue samples dedicated activities, and plan to dock in to autism research. The Brain Bank for Hobart, Australia. Autism in Oxford should reveal more detail on cellular and molecular changes during the development of the disorder than brain scans alone. Such a bank EUROPE may become a significant already exists in the US. source of “exported” measles in poor countries that have done a Mistaken reflections better job eliminating the virus. A study in The Lancet this Many birds, insects, reptiles and crabs week finds that the World Health become disorientated when exposed Organization is unlikely to meet to polarised light – made when light its goal of eliminating measles bounces off dark artificial surfaces such in the European region by 2010 as buildings and roads. Animals often because vaccination rates in many mistake the light for that reflected by countries, including Germany, the bodies of water, which many animals UK and Italy, are too low to stop and insects use as a guide to breeding the spread of the virus (DOI: sites and food sources (Frontiers 10.1016/S0140-6736(08)61849-8). in Ecology and the Environment, In contrast, Latin America DOI: 10.1890/080129). eliminated measles in 2002, but has since suffered outbreaks Flu fatalities “imported” from Europe. While measles rarely kills in Europe, in Bird flu continues to stalk the planet. poorer countries malnutrition This week, a 19-year-old woman in and limited healthcare make the Beijing died of the H5N1 virus. Last virus far more lethal, warns month, vaccinated chickens in Hong Jacques Kremer of Luxembourg’s Kong also died, which may be National Health Institute in an almost as bad as it suggests the accompanying editorial (DOI: virus is evolving. 10.1016/S0140-6736(08)61850-4).

Measles exporter

10 January 2009 | NewScientist | 5

International news and exclusives

PATRICK LANDMANN/SPL

This Thisweek– week–

–Every new nuclear plant means more fuel for weapons–

Could a fuel bank curb proliferation? Calls are growing for nations to place control of their nuclear fuel in international hands

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Security in Washington DC, an anti-proliferation think tank, say the country could have enough for a nuclear weapon this year. With some nations in the region already nuclear, neighbouring countries could feel pressure to follow suit (see “Nuclear Middle East”). At the same time, many are looking to acquire their own nuclear industries, meaning there will soon be far more weapons-grade material around (see graph, right). For most nuclear newcomers in the region and elsewhere, the move to nuclear power is largely independent of military concerns. Nuclear power capacity worldwide could almost double by 2030, says Vilmos Cserveny, head of external relations at

UNDER CONSTRUCTION Around half of the nuclear reactors now being built are in developing countries

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HOW do you manage a global boom in nuclear power while discouraging weapons proliferation? Uranium and plutonium are most likely to find their way into weapons via the enrichment and reprocessing of fuel for nuclear power plants. If all of the countries now planning to go nuclear also handle their own fuel cycles, the proliferation risk could skyrocket. The answer may be to put the fuel cycle entirely under international control. Many governments, international

agencies and arms control experts are calling for the establishment of international fuel banks, and eventually fuel production plants, that would pledge to supply nuclear materials to any country so long as it meets nonproliferation rules. The US already supports the idea, at least for new nuclear powers, and last month

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the European Union (EU) pledged €25 million towards the first fuel bank. Yet this means countries with new nuclear programmes would have to place control of their fuel supply at least partly in foreign hands. Could it actually work? Last year saw fresh predictions of the proliferation of nuclear weapons, especially in the politically explosive Middle East. The most critical situation is Iran, which has rejected international demands to stop enriching uranium. In a report released last month, the International Atomic Energy Agency (IAEA) warned that Iran’s uranium enrichment is expanding, and the agency could not exclude military use. Analysts at the Institute for Science and International

In this section ● How to give a female rat a male brain, page 8 ● The drinking dens of ancient Greece, page 10 ● Dimming sun may harm astronauts, page 11

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countries wary of any effort to ask them to rely on the nuclear powers for their energy security, says Oliver Meier of the Arms Control Association, a think tank based in Washington DC. Why would they place themselves at the mercy of foreigners for their energy? “Partly because it is very expensive to make and reprocess nuclear fuel,” Meier suggests. Spiralling costs are already leading to consolidation in the nuclear fuel industry, so a multilateral future may not be so unlikely, says Anthony. And for nations like Egypt and Iran, for example, a shared fuel source and stringent inspections would mean each could be sure that the other is not quietly proliferating – at least in theory. To further assuage concerns over shared fuel, Germany has suggested that some countries should cede sovereignty over a piece of territory where fuel cycle companies could build facilities that would then be run by the

NUCLEAR MIDDLE EAST Iran isn’t the only Middle Eastern nation that has observers worried about nuclear proliferation. Nine other countries in the region plan to build around 12 nuclear power plants over the next decade. This will produce enough plutonium in spent fuel for 1700 nuclear weapons, says David Albright of the Institute for Science and International Security in Washington DC, an anti-proliferation think tank. With nuclear weapons already in Israel, Pakistan, India and potentially Iran, there is motivation to acquire them. If the newcomers acquire fuel production and reprocessing facilities then the risk of material finding its way into weapons will rise sharply. Inspections might prevent this, but only eight countries in the region – including Iran – have signed the International

Atomic Energy Agency’s most stringent inspections agreement, known as the Additional Protocol. Only four countries enforce it. Egypt says it will never sign. Both it and Turkey reject a proposed moratorium on enrichment and reprocessing in the region put forward by, among others, Sweden’s Weapons of Mass Destruction Commission. Meanwhile, Gulf states have decided it makes business sense to sell their everscarcer oil and buy nuclear power for themselves. In December, the US agreed to sell a nuclear reactor to the United Arab Emirates. Both sides say the UAE will forego enrichment and sign the protocol. Yet it’s unclear whether the signed deal stipulates this, says Henry Sokolski, who serves on the US Congress’s anti-proliferation commission.

THE NEW NUCLEAR GENERATION The amount of plutonium in the Middle East, North Africa and Turkey is set to rise sharply 16

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report for the European Parliament published in December, Ian Anthony of the Stockholm International Peace Research Institute (SIPRI) documents nine separate proposals from experts and governments. Along with the IAEA fuel bank, there are four for putting existing enrichment plants under international control and four more to build new, super-safe enrichment plants that would

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be international from the start. Newcomers to nuclear power could be reluctant to put their fuel cycles in international hands if existing nuclear powers, such as the US, Russia and the UK, continue to control their own. Several proposals call for every nuclear country to join in. In fact, long-standing resentments over the rich world’s monopolisation of nuclear technology have made developing

SOURCE: INSTITUTE FOR SCIENCE AND INTERNATIONAL SECURITY

Estimated quantity of plutonium (tonnes)

the IAEA, mainly because poor countries face climbing oil prices and crippling electricity shortages. The problem is that countries that may not have the infrastructure needed to enforce stringent controls will be managing nuclear materials for the first time. Of the nuclear power plants now under construction, says Cserveny, around half are in developing countries, especially in Asia (see chart, below left). The world does not need more enrichment plants to fuel this expansion; there are plenty, especially in Russia. Of the 30 countries already with nuclear power, only 14 enrich their own fuel – the rest buy it in. However, some countries may be wary of depending on foreign powers for their energy and might want to make and reprocess their own fuel. Every new fuel plant increases the risk that fissile material will find its way into weapons, so the challenge is to find ways to guarantee fuel supplies without countries building their own facilities, says Cserveny. According to a growing number of analysts, agencies and governments, the solution is internationally managed reprocessing plants. The idea was first proposed in 1946, but no plan has ever been agreed on. In 2003, though, it resurfaced when IAEA chief Mohammed El-Baradei began promoting so-called multilateral nuclear arrangements (MNAs). In recent months, interest from countries that already have nuclear power has increased steeply. “Multilateral mechanisms should offer a real alternative to countries to forego developing their own national enrichment and reprocessing capabilities,” Javier Solana, EU high representative, said in Brussels in December. In a first step towards MNAs, the EU last month granted €25 million towards the creation of an IAEA emergency nuclear fuel stockpile that any country can tap should its commercial supply be cut off due to political disputes. It’s not the only proposal to ensure an international fuel supply. In a

IAEA. It could even be at Natanz, Iran’s enrichment plant, says Meier. This might seem unpalatable to some western governments, but “the alternative, Iran going it alone without inspections, is worse”, he says. Geoffrey Forden of the Massachusetts Institute of Technology thinks that Iran should set up a commercial partnership with western and regional governments to put Natanz under joint control. Iran would have to promise not to enrich anywhere else, and accept inspections; the IAEA-operated plant would then make enough fuel for Iranian reactors and those in the rest of the region. Staff would be multinational and chances for subterfuge would be limited. “The plan meets the bottom line on both sides,” he says. ● 10 January 2009 | NewScientist | 7

This week–

Medicinal plants on verge of extinction THE health of millions could be at risk because medicinal plants used to make traditional remedies, including drugs to combat cancer and malaria, are being overexploited. “The loss of medicinal plant diversity is a quiet disaster,” says Sara Oldfield, secretary general of the NGO Botanic Gardens Conservation International. Most people worldwide, including 80 per cent of all Africans, rely on herbal medicines obtained mostly from wild plants. But some 15,000 of 50,000 medicinal species are under threat of extinction, according to a report this week from international conservation group Plantlife. Shortages have been reported in China, India, Kenya, Nepal, Tanzania and Uganda. Commercial over-harvesting

Treat a female rat like a male and its brain changes STROKE the belly of a newborn female rat for a few hours a day and chemical “caps” will appear on its DNA that make its brain look more like that of a male. This extraordinary finding suggests that some biological differences between male and female brains may not be decided during fetal development, but instead appear after they are born. According to traditional thinking, sex-specific differences in mammals are determined in the womb by genes on the X and Y chromosomes, with the prenatal hormones the fetus is exposed to also playing a role. Recently, however, it has become 8 | NewScientist | 10 January 2009

does the most harm, though pollution, competition from invasive species and habitat destruction all contribute. “Commercial collectors generally harvest medicinal plants with

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clear that the behaviour of a mother rat towards her offspring can cause sex-specific changes. For example, mother rats spend more time licking and grooming their sons, which previous studies suggest is necessary for their genitalia to form properly. To see if a mother’s touch might also cause sex-specific changes in rats’ brains, Anthony Auger at the University of Wisconsin, Madison, and colleagues stroked baby female rats, giving them the attention normally reserved for males. They found that the number of oestrogen receptors in the hypothalamus of stroked females was lower than in unstroked females, and similar to levels found in males. When the team examined the brains more closely, they noticed that the pattern of chemical caps called methyl groups that sit on DNA resembled that found in males, with more caps on the gene that codes for

used to treat a prostate condition. The solution, says the report’s author, Alan Hamilton, is to provide local communities with incentives to protect these plants. Ten grass-roots projects studied by Plantlife in India, Pakistan, China, Nepal, Uganda and Kenya showed this approach can succeed. In Uganda, the project has ensured the sustainable supply of low-cost malaria treatments, and in China a community-run medicinal plant reserve has been created for the first time. “Improving health, earning an income and maintaining cultural traditions are important in motivating people to conserve medicinal plants, and thus the habitats,” says Hamilton. “In conservation you’ve got to go with what people are interested in.” Ghillean Prance, the former director of the Royal Botanic Gardens at Kew in London, agrees that medicinal plants are in dire need of protection. “Not nearly enough is being done,” he told New Scientist. “We tend to destroy the very plants that are –The local drug store– of most use to us.” ●

little care for sustainability,” the Plantlife report says. “This can be partly through ignorance, but [happens] mainly because such collection is unorganised and competitive.” Medicinal trees at risk include the Himalayan yew (Taxus wallichiana), a source of the anti-cancer drug, paclitaxel; the pepper-bark tree (Warburgia), which yields an antimalarial; and the African cherry (Prunus africana), an extract from which is

oestrogen receptors. As the caps reduce gene expression, this higher number of methyl groups is likely to be responsible for the decrease in oestrogen receptors. As methylation is often permanent, the methylation patterns caused by a mother’s stroking may also be long lasting, says Auger, who presented the findings at the Society for Neuroscience meeting in Washington DC in November. Methylation is “a short cut, a way for organisms to reduce the amount of information they have to encode in their genome,” says Julie Markham of the University of Maryland School of Medicine in Baltimore. This is the first time that

“This is the first time that epigenetic influences outside the womb have been linked to sex differences in mammals”

“epigenetic” influences outside of the womb have been linked to sex differences in mammals. Whether a human mother’s behaviour has a similar effect on a baby after it is born, and on brain development specifically, is not known. Celia Moore at the University of Massachusetts, Boston, says that further research should probe whether human mothers treat sons and daughters differently, and what effect, if any, that has on brain development. “Sex may not be just genes and hormones,” she says. Understanding any differences in male and female brain development might help to explain why some conditions affect the two sexes unequally. Depression is twice as common in women as in men, for example, and men and women respond differently to head injuries, strokes, Parkinson’s and Alzheimer’s disease. Devin Powell ● www.newscientist.com

How butterflies up the ante in sperm wars BUTTERFLY sex is not as elegant an affair as you might think. It seems that male monarch butterflies conduct an all-out sperm war based on a crude measure of how much sperm is stored inside a female from a previous mating. During sex the males physically restrain the females for an entire day while injecting them with a fluid which contains fertile sperm as well as seemingly functionless cells without nuclei. Michelle Solensky of The College of Wooster in Ohio paired male monarch butterflies with a selection of females that had had

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different numbers of partners. She found that males could selectively increase or decrease the amount of fertile sperm in their deposits. For example, they deposited slightly more into a female for each of her previous mates (Animal Behaviour, DOI: 10.1016/j.anbehav.2008.10.026). “This may explain earlier observations that the last male to mate has a reproductive advantage,” says Solenksy. She then arranged for some female butterflies to receive a large deposit from a single male, and others to have a small deposit from three different males

adding up to a similar volume. When males later mated with the females, they used the same amount of sperm irrespective of which experimental group the female butterfly had been in. This showed that the males were adjusting their sperm on the basis of volume – not the number of previous partners. “I don’t know of any other creatures that respond to the amount of sperm inside their mates,” says Solensky. “The new aspect for butterflies is that they can assess the intensity of sperm competition without ever witnessing previous matings,” says Simone Immler at the

“Sensors on the male monarch butterfly’s penis may detect the volume of sperm directly, like the dipstick in a car’s oil tank”

University of Sussex in the UK. Because monarch butterflies do not use chemical signals like pheromones, Solensky suspects that sensors on the male penis detect the volume directly, like the dipstick in a car’s oil tank. If so, the cells that lack nuclei may act to bump up the volume of the deposit and discourage rivals. This behaviour backs a theory that males of some species can boost their sperm levels to raise the odds of passing on their genes. Male fish, for example, release more sperm into the water when they sense a nearby rival. Even men who spend more time bonding with their girlfriend unconsciously release more sperm during sex. “Males can be just as choosy as females; sperm may be cheaper to make than an egg, but it still isn’t free,” says Solensky. Devin Powell ●

10 January 2009 | NewScientist | 9

This week–

MRI scans could soon be used to show who is at risk of a heart attack. At the moment the only way is to use an invasive probe that can itself trigger cardiac arrest. A major cause of heart attacks is plaques made of immune cells and cholesterol that build up inside the coronary arteries, which feed the heart. If a plaque ruptures, a clot can form, blocking blood flow with potentially catastrophic results. While cameras can be sent into arteries to check the walls for plaques, the probe itself might rupture a plaque. An MRI scan can see inside the body without risk, but doesn’t provide enough resolution to

image artery walls directly. However, Simon Robinson of Lantheus Medical Imaging in North Billerica, Massachusetts, and his colleagues found a way around this using gadolinium chelate, a substance which is already used to light up blood in MRI scans. They attached this “contrast agent” to a molecule that binds to the protein elastin, which is found in artery walls. When injected into the bloodstream of pigs, the resulting molecule binds to elastin throughout the thickness of the artery walls and lights them up in an MRI scan (see image). The plan is to image the arteries

of people thought to be at risk of heart attack and check for a dangerous amount of thickening that would suggest the presence of plaques. “If you’ve got a plaque developing, you’ll see a brighter, thicker region,” Robinson says. Patients with plaques could be given cholesterol-lowering drugs, such as statins, blood thinners that prevent a clot from forming if a plaque ruptures, or fitted with a stent to support artery walls and lower the risk that a plaque will burst. The gadolinium chelate eventually detaches from the artery walls and is cleared by the kidneys. “There is an enormous need for new ways of imaging these plaques, which contribute to stroke, heart attacks, renal disease and peripheral vascular disease,” says radiologist Mohammed Hamady of St Mary’s Hospital in London.

A good night out began at home in ancient Greece IT’S a wonder the Greeks accomplished as much as they did, as many of their homes seem to have doubled as pubs and brothels. This finding, from new analyses of archaeological remains, could explain why previous hunts for evidence of ancient Greek taverns have been fruitless. Plays from classical Greece describe lively taverns, but no one has ever unearthed their real-life versions. Clare Kelly Blazeby at the University of Leeds, UK, suspected that archaeologists were missing something, so she took a new look at artefacts from several houses dotted around ancient Greece, dating from 475 to 323 BC. These had all yielded the remains of numerous drinking cups, and so had been assumed to be wealthy residences. Kelly Blazeby now believes a more likely explanation is that the residents regularly sold wine. Her analysis suggests that many of the houses had hundreds 10 | NewScientist | 10 January 2009

IMAGE THAT ARTERY MRI scan of artery in healthy pig AORTA

SOURCE: LANTHEUS MEDICAL IMAGING / RENÉ BOTNAR

Artery highlighter could reveal heart attack risk

ARTERY WALL

Lantheus is conducting safety trials of the contrast agent and hopes to begin tests in humans early in 2010. One possible obstacle is that some gadoliniumbased contrast agents have previously been linked to kidney problems. Linda Geddes ● of cups – far too many for a building used only as a residence, she says. Other archaeological artefacts suggest the houses were used for other functions too. “This blows apart everything that people think about drinking in classical Greece,” says Kelly Blazeby, who is presenting her findings on 10 January at the annual meeting of the Archaeological Institute of America in Philadelphia, Pennsylvania. She is not alone. Allison Glazebrook of Brock University in St Catharines, Ontario, Canada, will tell the same conference that some of the houses doubled as brothels. Telltale signs that Glazebrook found include erotic graffiti and objects, and clusters of clay drinking cups. “This has a real impact on how we view the economy in classical Greece,” says Kelly Blazeby. “A lot of trade and industry was based within the home.” Lin Foxhall at the University of Leicester, UK, a specialist on life in ancient Greece, agrees. She says Kelly Blazeby’s analysis highlights “the diversity of activities and types of residents that might have inhabited the buildings we call ‘houses’ in the highly urbanised cities of classical Greece”. Emma Young ● www.newscientist.com

Danger ahead as the sun goes quiet THE sun’s ability to shield the solar system from harmful cosmic rays could falter in the early 2020s, just in time to threaten the health of NASA astronauts as they return to the moon. As well as the 11-year cycle of sunspots and solar flares, the sun’s activity experiences longerterm shifts lasting several decades. The sun is currently in a longterm high, having been relatively active for nearly a century, but it is not known when this will end. To find out, a team led by Jose Abreu of the Swiss Federal Institute of Aquatic Science and Technology in Duebendorf analysed 66 long-term highs from the past 10,000 years, as recorded in fluctuating levels of rare isotopes such as beryllium-10 in ice cores from Greenland. These are produced when cosmic rays break down the nuclei of oxygen and nitrogen atoms in the Earth’s atmosphere. Production of these isotopes peaks when the sun is inactive, as the weaker solar wind lets more cosmic rays enter the solar system, which hit the Earth.

Clouds overhead? Maybe bacteria are to blame BACTERIA may be able to make it rain without ever leaving the ground – if the powerful detergents they produce can reach the clouds, that is. Previous studies have suggested that bacteria can affect cloud formation. For example, an analysis of snow samples has hinted that bacteria swept up into the atmosphere trigger precipitation so that they can return to the ground. www.newscientist.com

Based on the duration of past highs, and the fact that the current one has already lasted 80 years, the team has calculated that its most likely total lifetime is between 95 and 116 years, and they suspect the high will probably end at the shorter end of this range

the late 16th to mid 19th century, leading some to suggest a causal link, this correlation could be a coincidence, Weiss says. Weiss also points out that the sun’s brightness changes only slightly with variations in activity. If the sun does dim slightly in the coming decades, he says, this would only reduce the warming expected due to human-induced climate change by 0.1 °C. “It might be discernible, but it would be a blip rather than a major change,” he says. “It is nothing [compared] with the global warming that is now being produced through pumping of greenhouse gases into the atmosphere.” Those most likely to be affected would be astronauts. Beyond the Earth’s protective magnetic field, their exposure to the increased cosmic rays let into the solar system due to a weaker solar wind could cause cancer and fertility loss. One benefit to astronauts would be a decline in the number of solar flares. David Hathaway of NASA’s Marshall Space Flight Center in Huntsville, Alabama, says the evidence for past lulls is strong, but he is sceptical about the team’s attempt to predict the arrival of the next one. “This is a little like trying to predict when someone’s winning streak will end,” he says. “We know that it will happen, but reliable predictions are –Solar flares, bad news for astronauts– virtually impossible.” ● SOHO/ESA/NASA/SPL

DAVID SHIGA

(Geophysical Research Letters, DOI: 10.1029/2008GL035442). Records of the sun’s brightness during the 20th century show that it gets slightly dimmer when it is less active, so could a longterm reduction in activity help to offset global warming? No such luck, says Nigel Weiss from the University of Cambridge, who is a member of Abreu’s team. While there is a rough correspondence between a period of very low activity from 1645 to 1715 and the middle of a period of lower average global temperatures lasting from

Now Barbara Nozière of Stockholm University, Sweden, and colleagues suggest that surfactants secreted by many species of bacteria could also influence the weather. While these are normally used to transport nutrients through membranes, the team have shown that they also break down the surface tension of water better than any other substance in nature. This led them to suspect that if the detergent was found in clouds it would stimulate the formation of water droplets. To find out if they were present in the atmosphere, Nozière collected air samples over a coastal region, an ocean, a forest and a jungle at

locations in Brazil, Sweden and Finland. Particles in all the samples contained minute amounts of detergent with a chemical structure that resembled the surfactants. It also broke down the water into droplets in the same way. “The only thing we know of that could cause this strong an effect is the bacterial surfactants,” Nozière said in a presentation at last month’s meeting of the American Geophysical Union in San Francisco.

“If the detergent from bacteria was found in clouds, it would stimulate the formation of water drops, causing rainfall”

Nozière suggests that the bacteria may be helping to keep the atmosphere healthy and active. She also speculates that they evolved the ability to summon water from the sky to help them survive. The next step will be to work out how these substances get up to the clouds, says Andi Andreae of the Max Planck Institute of Chemistry in Mainz, Germany. Only a small proportion of cloud-forming particles come from the ground, carried by the wind. “This bacterial gunk could hitch a ride on particles that travel from the surface to the clouds and supercharge them,” he says. Devin Powell ● 10 January 2009 | NewScientist | 11

Research news and discovery

DAVID HANOVER/GETTY

In brief– Beat generation

Other men all smell the same if a boyfriend’s on the scene WHEN you’re in love, everything seems different – and that includes smells. Compared with their less besotted counterparts, women who are madly in love struggle to recognise the body odours of male friends. So say Johan Lundström and Marilyn Jones-Gotman of McGill University in Montreal, Canada. They asked 20 young women with boyfriends to fill in a questionnaire called the Passionate Love Scale to rate how deeply in love they were. They also persuaded the women’s partners and male and female friends to sleep for seven nights in a cotton T-shirt.

The women were asked to sniff the shirts to distinguish those worn by their lovers and friends from those of strangers. The more deeply in love a woman was, the less well she did at distinguishing a male friend’s odour from those of strangers. When it came to recognising the odours of male lovers or female friends, however, the women’s love score was unrelated to how well they did (Hormones and Behavior, DOI: 10.1016/j.yhbeh.2008.11.009). This suggests a lover doesn’t pay more attention to her partner – just less to potential suitors. “I’m not really a love guru,” protests Lundström, now at the Monell Chemical Senses Center in Philadelphia, Pennsylvania. His next project will investigate what happens in lovers’ brains as they perceive the odours of partners, friends and strangers.

Thyroid hormone repairs MS damage POINTERS to possible drug treatments for multiple sclerosis have come from an experiment in which extra doses of a natural hormone relieved symptoms of the disease in mice. In MS, the immune system attacks and destroys the fatty myelin sheath around nerve cells, causing physical and cognitive disability. Myelin is produced by cells called oligodendrocytes, 12 | NewScientist | 10 January 2009

whose development is controlled by the hormone triiodothyronine, which is made in the thyroid. To see if extra doses of this hormone might help to “remyelinate” nerves, Said Ghandour at the Louis Pasteur University in Strasbourg, France, and colleagues gave mice a chemical that destroys myelin, causing a mouse version of MS. The mice had seizures and lost

the ability to coordinate their movements. When the mice then received injections of the thyroid hormone for three weeks, these symptoms improved (The Journal of Neuroscience, DOI: 10.1523/ JNEUROSCI.4453-08.2008). In people, an overactive thyroid can cause nervousness, heart palpitations and weight loss. As Ghandour fears extra doses of the hormone might do the same, he suggests creating drugs to mimic the hormone’s effect on the brain but not the rest of the body.

WHAT controls a beating heart? It seems the life-giving mechanism is simpler than we thought. Each beat is triggered by a surge of calcium ions that causes millions of overlapping filaments in a heart cell to pull against each other and contract. These filaments are made of two proteins called actin and myosin. Actin must be “activated” before contraction can occur and it was thought that both calcium and myosin were necessary for this step. But when Yin-Biao Sun at King’s College London and colleagues, funded by the British Heart Foundation, attached fluorescent probes to rat versions of the proteins, calcium ions alone seemed to activate actin (The Journal of Physiology, DOI: 10.1113/jphysiol.2008.164707). A persistent abnormal heart beat causes many heart problems, so a better understanding of how healthy beating is controlled may aid new drug development.

Right stuff for the dark stuff THE brightness of white dwarfs may point towards the existence of exotic dark matter particles. Jordi Isern of the Institute of Space Sciences in Bellaterra, Spain, and colleagues modelled what would happen if white dwarfs – small, dense, dying stars – were emitting axions. These hypothetical particles are a candidate for dark matter, which makes up most of the universe. The model showed that axion emission affected a white dwarf’s brightness, and the distribution of stars of a given luminosity predicted by the model matched well with observations of 6000 white dwarfs by the Sloan Digital Sky Survey (www.arxiv.org/ abs/0812.3043). This is the first indication that axions could exist, say the team. www.newscientist.com

Comment and analysis–

Move over, polar bear I HAVE a problem with the polar bear – or at least with its status as an icon for the perils of global warming. Sure, this magnificent animal is being assailed by rising temperatures and vanishing habitat. But when it comes to convincing people of the need for action on climate change, the threat to the polar bear doesn’t come close to representing the urgency of the situation. A much greater danger is faced by the thousands of species – including many large, photogenic mammals – living in tropical rainforests. These lush forests are the world’s most diverse ecosystems. With an area of 25 hectares – the size of 50 football fields – going up in smoke every minute, it’s clear that wildlife there is massively at risk from habitat destruction. What may be less obvious is that species already adapted to sultry conditions are at dire risk from global warming. Compared to those in cooler climates, tropical species can cope with only a narrow temperature range. Unlike their northern counterparts, they enjoy balmy weather all year, so have never adapted to freezing winters alternating with warm summers. Because of this, most tropical species are also limited to particular elevations. Animals living in the lowlands rarely climb mountains because temperatures drop by about 1 °C for every 100-metre increase in altitude. Even a 500-metre ridge can halt many lowland species in their tracks. Similarly, most mountaindwelling species find the sweltering lowlands unbearable. Adapted for cool, cloudy conditions, their populations become isolated on particular peaks, which is why each mountain or chain of mountains tends to spawn scores of unique local species. A clutch of recent papers have underlined the risks these species face from global warming. Animals endemic to mountains in the tropics may be among the most vulnerable. “As the world gets hotter, these creatures have nowhere to go,” says Stephen Williams from James Cook University 14 | NewScientist | 10 January 2009

ANDRZEJ KRAUSE

As icons for the victims of global warming, the most obvious species may not be the most deserving, says biologist William Laurance

in Queensland, Australia. “Their populations will wither and collapse until eventually they just disappear into heaven.” Williams and his colleagues have modelled the responses to global warming of every endemic bird, mammal, frog and reptile species in the rainforests of north Queensland (Proceedings of the Royal Society B, vol 270, p 1887). Their conclusions are stark. If average temperatures rise by more than 2 °C – which could easily happen this century – extinctions will spike dramatically. The first species to go may be the white lemuroid possum (Hemibelideus lemuroides), a striking animal confined to a cool mountain top in north Queensland. It hasn’t been seen by anyone in three years – and I spent a long night in 2008 searching for it myself. Williams reported last month that it may already be extinct. The last straw could have been a heatwave that hit the region in late 2005, when dead possums of several species were found along forest roads. Species in the tropical lowlands are

“The white lemuroid possum of northern Queensland hasn’t been seen in three years”

vulnerable too. Biologist Raymond Huey at the University of Washington, Seattle, argues that many lowland species are living dangerously close to their thermal maximum. He points out that anolis lizards can die if heated to just a few degrees above their preferred foraging temperature. And during a recent summer heatwave, flying foxes in subtropical Australia died in droves (Proceedings of the Royal Society B, vol 275, p 419). At least 3500 of the giant bats succumbed to the heat in one day. Such die-offs may prove irreversible, according to a study led by Robert Colwell at the University of Connecticut, Storrs, and published in October (Science, vol 322, p 258). As global temperatures rise, the authors conclude, species living near the foot of tropical mountains will migrate into the uplands, and mid-elevation species will move even higher. But lowland species with no mountains nearby, such as those in the vast Amazon and Congo basins, will have nowhere to go. We seem to have reached the point at which global warming rivals habitat destruction as a threat to tropical biodiversity – or at least the two threats reinforce each other. Increasing habitat loss is likely to trap forest species, stopping them from seeking more favourable climates or elevations. The fragmented populations that remain will be battered by heatwaves, droughts, storms and other effects of global warming. Many will vanish forever. It’s an alarming scenario, and it has tropical biologists wondering which battle to fight first: habitat destruction or global warming. I believe that slowing habitat loss is the higher priority, in part because the rapid destruction of tropical forests produces about one-fifth of all greenhouse gas emissions today. Saving rainforests is one of the most effective ways to fight global warming, as well as helping to preserve some of the Earth’s most imperilled species and ecosystems. Perhaps we should also adopt the white lemuroid possum as an icon for the victims of global warming. Given that tropical species endangered by global warming probably outnumber their polar counterparts by 1000 to 1, it seems fitting. ● William Laurance is at the Smithsonian Tropical Research Institute in Panama www.newscientist.com

Letters– Multiversality From Peter White Amanda Gefter contends that we are being offered a choice between God and a multiverse as explanations for our existence (6 December 2008, p 48). Consider a third possibility: that our universe is an artefact created by an advanced species and

contained within the universe in which that species exists. It would be difficult to test this hypothesis, but at least it avoids invoking the supernatural. I sometimes suspect that our universe is some cosmic engineering undergraduate’s final-year project – though, if so, it’s probably not worth more than a second-class degree. Tongwynlais, Cardiff, UK From Mark Vernon Amanda Gefter is surely right when she says that an explanation for anthropic effects is not a straight choice between two explanations: multiverse or divinity. However, it is far from obvious that the notion that observation creates the universe – so-called top-down cosmology – can straightforwardly be called science. In his recent book The Goldilocks Enigma, Paul Davies admits that such a “selfexplaining universe”, containing a “life principle”, will seem crypto-religious to many – though he is quite clear that he is not appealing to any supernatural agency. What it would necessitate, though, is a way of integrating 16 | NewScientist | 10 January 2009

into physics the elements that make for human observation: namely, life, mind and purpose. That sounds a lot like making an appeal to metaphysics, or at least as the physicist Roger Penrose would have it, a very different concept of science from that which exists today. London, UK From Helen Logan Of course our universe appears finely tuned for our existence. Altering any number of variables would mean we could not exist. But surely all we are observing is that we exist within the current conditions. If those conditions were to change might not another conscious being appear and assume in turn that those conditions were finely tuned for its existence? This observation doesn’t seem to me to require a multiverse or a deity. Cheltenham, Gloucestershire, UK The editor writes: ● Most of the universes we can imagine would not support any sort of complex structures, which we assume are necessary for any sort of life, even something completely different from any life we might imagine.

Something for nothing From John Turner Lawrence Krauss seems to have strayed into the foothills of metaphysics without realising that he hasn’t brought the proper equipment (22 November 2008, p 53). He starts with the question “why is there something rather than nothing?” and claims that physics has largely answered this question by “reframing” it as “how” rather than “why”. This is not reframing – this is just a different question. Physics can create a partial description of how the universe came into being, and that can be a useful thing, but it does not advance our understanding of why any more than a mapping of

the human genome tells us why human beings exist. Krauss concludes that “science has once again altered the playing field for such metaphysical speculations in a dramatic and beautiful way”, whereas in fact it is he who has altered the playing field in a blatant and predictable way by ignoring the difference between a question of causation and a question of meaning. Welwyn Garden City, Hertfordshire, UK

Mathematics is hard From John Campion Marcus du Sautoy declares that we can all do mathematics because we are naturally programmed to do so (29 November 2008, p 44). Being able to survive by moving around in the world and manipulating objects in it with speed and precision has nothing whatever to do with mathematics. The survival skills he alludes to are achieved through the natural acquisition and use of perceptualmotor schemata developed over many thousands of hours of practice. Being necessary for our continued existence, it is what humans are generally very good at. Mathematics, on the other hand, is the description of such activities using an unnaturally acquired formal system of symbol notation and manipulation. It is a different skill with different aims, employing different types of knowledge and using different parts of the brain. Being unnecessary for survival, it is what humans are generally very poor at. There is nothing more irritating and off-putting than some expert airily declaring that it’s all very simple really, when it self-evidently isn’t. If du Sautoy wants to meet his brief of furthering public understanding of science, he should start by coming clean on these matters. Liphook, Hampshire, UK

Sex, lies and surveys Name and address supplied Prompted by the article on sexual strategies (29 November 2008, p 32), I took a small informal poll at the school where I work. Seventeen out of 20 boys and six out of 10 girls said they would probably lie on a questionnaire about their sex life, even if they completed it anonymously. If it was not anonymous, all 20 boys said they would have lied, as did eight of the girls. Of course, they might have been telling lies. From Rupert Vidion, Department of Urology, Wellington Hospital You quote Anne Campbell from Durham University as saying that where there are fewer males than females “men can call the shots, and what men usually want is casual sex”. I feel this misses an important point. While a stable partnership may be desirable for raising a child, it is not essential to producing the next generation. When there are fewer males, it is also to females’ advantage, assuming they wish to procreate, for relationships to be less stable. With stable relationships, the limiting factor is the number of males in the population. If lessstable relationships predominate, females have a greater likelihood of finding a mate, however temporary, and reproducing. Wellington, New Zealand From Andrew D. Carothers In considering optimal sexual strategies we should bear in mind

www.newscientist.com

See newscientist.com for letters on: ● Multiversality ● Something for nothing

that evolutionary pressures act to maximise the number of genes passed on to posterity, and not simply to the generation immediately following (29 November 2008, p 32). So the advantage to a female of choosing a promiscuous mate is that the male offspring of such a mating may themselves inherit promiscuous genes, and thereby pass on more of the mother’s genes to the grandchildren and subsequent generations. Better still, if she can deceive her “regular” partner she gains his support to maximise the children’s chances of surviving to reproduce. Of course, this is risky – he may find out and abandon her. It is precisely because different reproductive strategies have such finely balanced pros and cons that so many exist in human societies. How boring our television, literature and theatre would be without them… Edinburgh, UK

Menstrual chaos From Laura Spinney Caroline Williams writes of the menstrual synchrony effect in humans, first described by Martha McClintock in the 1970s, that, “McClintock’s conclusions remain contentious because nobody has yet isolated the actual chemicals that cause the effect” (6 December 2008, p 38). They remain contentious because of much more than that. Others have tried and failed to find the effect. In 2006, for example, Zhengwei Yang of the North Sichuan Medical College in Nanchong, China, and Jeffrey Schank of the University of California, Davis, studied the phenomenon in two ways. First, they collected data from 186 Chinese women who had been living in dormitories for more than a year. They found no evidence of menstrual synchrony. Second, they reviewed McClintock’s original data, and found that group synchrony was www.newscientist.com

main breed: the Weimaraner breed club decided against this to maximise the gene pool. Templecombe, Somerset, UK

Animal welfare

at the level of chance. “We then show that cycle variability produces convergences and subsequent divergences of cycle onsets and may explain perceptions of synchrony,” they wrote in the journal Human Nature (vol 17, p 433). London, UK

Dog standard From Sally Morgana and Sally Damms, Weimaraner Club of Great Britain Weimaraner Club members were disappointed to read Paul McGreevy saying that the breed standard for Weimaraner dogs – which demands that the chest is “well developed, deep” while the abdomen is “firmly held” and the flank is “moderately tucked-up” – “may help to make Weimaraners appear athletic, but puts them at risk of gastric dilation and torsion” (11 October 2008, p 18). The cause of bloat and gastric torsion is not known and most breeders consider that bloat can be linked to many triggers, not least diet and stress. If there were a proven link between a welldeveloped chest and bloat, breeders would be at the forefront in taking action against this dreaded condition. One word crops up time and time again in the standard description of the breed – “moderate”. Any moves towards exaggeration have been resisted. McGreevy raises the issue of a closed stud book. In many breeds, variants such as long hair or wire hair have been separated from the

From Marc Bekoff, University of Colorado, Boulder I was thrilled to read A. C. Grayling on our duty towards fellow animals (29 November 2008, p 50). Severe restrictions on invasive animal research are long overdue, and the European Union’s proposal to ban all but behavioural research on great apes is an important step forward. Those who think “good welfare” is good enough need only know that in the US alone in 2006 there were more than 2100 known violations of the federal Animal Welfare Act – even though more than 99 per cent of animals used in research are not protected by this legislation. Over the past five years, violations have increased by more than 90 per cent: see www.all-creatures.org/saen/ Boulder, Colorado, US

solving to my subconscious, giving it a deadline of anything from two hours to two months. On most occasions it has come up with something useful that my conscious mind hadn’t thought of. I always make sure that the conscious does not address the matter again before the set deadline, for fear that it would mess things up. Leatherhead, Surrey, UK

Eco-charging From Jay M. Pasachoff In your eco-questions and answers, your discussion of how best to charge a laptop left a major topic unanswered: what if you use the laptop as a main computer, normally just plugged into the mains – or “to the wall” as we say in the US (15 November 2008, p 36)? Is it better to keep unplugging it and using it until the battery runs down, or to leave it plugged in all day, or even for weeks on end? Pasadena, California, US The editor writes: ● To minimise bills, charge the battery and use it until it’s empty.

The private brain From Peter Harrison Douglas Fox describes work that seems to imply that the conscious brain needs to be inactive for the subconscious one to work (8 November 2008, p 28). I would say that the requirement is that it should be inactive only on the topic of concern and that activity on unrelated topics is a necessary distraction. Nearly 30 years ago, I decided that my subconscious mind had a greater capacity and was often more useful than my conscious mind. This arose from the experience – one that many of us have – of unsuccessfully trying to remember something, only for it to pop up into my consciousness out of the blue while I was engaged in an unrelated activity. Since then, I have often consciously handed over decision-making and problem-

Tamed, who? From Frank Spence Piers Bizony says “recent military events in Georgia have reminded [the European Space Agency] that Russia may not yet be a fully tamed member of the international community” (15 November 2008, p 22). The way the UK and the US go rampaging round the world, bombing at will, raises an obvious question. Reading, Berkshire, UK

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10 January 2009 | NewScientist | 17

UPPER CUT/GETTY

Technology AN EVERLASTING CRIME SCENE

NASA appears to have cancelled its research into space-based solar power (SBSP) systems – orbiting solar arrays that beam microwaves to receivers on the ground, where the energy is converted to electricity. Seen as one technology for combating climate change, SBSP faces major challenges – including the cost of launching hundreds of square kilometres of solar arrays to an altitude of 36,000 kilometres. Now a letter leaked to the NasaWatch.com blog says the space agency “does not have the resources available to support a proposed demo for SBSP”. Advocates of the technology are still urging President-Elect Obama to adopt it by posting pro-SBSP research papers on his change.gov website. Some members of his transition team are also thought to support solar power from space.

36 gigabytes of data have been sent back by NASA’s Spirit and Opportunity rovers during their five years on Mars

–Always there if you need it–

The robot with the tender touch

SOURCE: BBC NEWS ONLINE

Lack of cash sinks power from space

system, in which a number of “satellites” placed on tripods around the scene emit laser pulses. These are detected by sensors fitted to the scanner, allowing the device to calculate its position by triangulation. At least 20 of these laser beacons are needed, says Valkenburg – the more beacons, the greater the accuracy. As the device is swiped in front of objects, walls or other surfaces, they automatically appear on screen “like brushstrokes”, says Valkenburg, as part of the emerging 3D model. A number of other scanning technologies are available, but none can capture scenes with such photorealism, he adds. The device could also be used to scan heritage sites, historical artefacts and movie and video game props, Valkenburg says.

One in 10 students display their phone number on their social networking web page INFORMATION COLLEGE STUDENTS SAY THEY INCLUDE ON THEIR SOCIAL NETWORKING SITES PHOTOGRAPH

86%

FULL PROFILE VIEWABLE INSTANT MESSAGING ADDRESS 49% EMAIL ADDRESS

35%

PHONE NUMBER 9.4% HOME ADDRESS 9.4%

74%

BEING held in a robot’s steely grasp need not be as uncomfortable as it sounds. Previous attempts to use robots to guide limbs have required the person concerned to be strapped to them. Now a team at the University of Karlsruhe, Germany, is developing a human-sized machine which is able to lightly hold a person’s forearm and steer

them in the appropriate direction. The team has equipped the robot with a camera at neck height that detects the person’s position. A sensor on its palm guides its movements as it reaches out to touch the person’s forearm, while touch sensors on its fingertips adjust its grip to prevent it being too heavy-handed. If the person starts to wriggle, the robot quickly releases its hold. The work was presented at the Humanoids 2008 conference in Daejeon, South Korea, last month.

GIZMO

CALL ME

SOURCE: COMPUTERS IN HUMAN BEHAVIOR

Forensics experts and road-accident investigators could soon revisit the scene of a crime without leaving their office, thanks to a 3D scanner that “paints” a virtual model of the area. The hand-held scanner makes it possible to record a scene with millimetre accuracy and creates a computerised 3D model that can be navigated as if investigators were at the site, says Robert Valkenburg of Industrial Research in Auckland, New Zealand, which developed the technology. The device consists of a laser scanner coupled to a digital camera. The scanner creates a 3D model of the scene, onto which images from the camera are overlaid. To ensure this is done accurately, the device needs to keep a constant track of its position. It achieves this using a sort of local GPS

Touch-screen technology looks set to flood shopping malls in 2009. At the Consumer Electronics Show this week in Las Vegas, KYE Systems of Taiwan introduced hi-fi speakers with an illuminated touch panel that lets users change volume, bass and treble “with a glide of the finger”. It also introduced a digital photo frame that allows the picture or slide show to be changed using a similar touch screen. Nanotechnologists have built a mechanical switch that changes with temperature. A team at Osaka University in Japan constructed a carbon nanotube that moves back and forth inside a larger closed nanotube (Nano Letters, DOI: 10.1021/nl802323n). Electrostatic forces bind the internal nanotube to one end of its container, but heat breaks this bond, allowing the tube to slide and bind to the other end.

“Cisco was founded two weeks before a stock market crash” Silicon Valley venture capitalist Paul Holland, a general partner at Capital Foundation, puts a brave face on the prospects for 2009 on the principle that bad times produce the best investment opportunities (The New York Times, 4 January)

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10 January 2009 | NewScientist | 19

Cool your brain, save your mind

Heart attacks and strokes can cause brain damage, but a quickly chilled brain is a harder nut to crack DAVID ROBSON

ARGONNE NATIONAL LABORATORY

BRIDGET HARRIS lies on a hospital bed with a nylon hood covering her head. As cold air streams from the hood and over her scalp, her lips gradually turn blue and her speech slows. Within an hour, her core body temperature has dropped by 0.5 °C, but she remains comfortable. “The airflow is almost relaxing,” she says. “It sounds like white noise.” Harris, a PhD student at the University of Edinburgh, UK, is testing her own invention: a cooling helmet designed

–Cooling a kidney with icy slurry– 20 | NewScientist | 10 January 2009

to induce mild hyperthermia. We all know that a cool cloth applied to the forehead can ease a headache, but now researchers like Harris are investigating whether technologies that cool the brain itself could prevent brain damage following a stroke or cardiac arrest. Similar techniques could also protect the heart and kidneys from damage during surgery. For some time, doctors have observed that cooling patients following a heart attack can reduce brain damage. Although they are not yet sure of the mechanism behind this effect, researchers suspect that cooling

the brain by 4 °C, to around 33 °C, reduces the metabolism of brain cells, reducing their hunger for oxygen for the crucial moments during which blood is in short supply. Damage seems to be reduced even if the brain is only cooled once the heart has been restarted, suggesting that cooling may also slow the release of toxic chemicals from neurons and glial cells – a process called the ischaemic cascade, which triggers further brain-cell death up to 24 hours after a cardiac arrest or stroke. Previously, doctors have induced “therapeutic hypothermia” by applying ice packs or cooling blankets to the whole body, or injecting cold saline solution into the veins. However, cooling the whole body can increase the risk of infection and pneumonia, so researchers are now building targeted devices that chill the brain directly. Harris’s hood, for example – developed with her supervisor Peter Andrews and medical technology company KCI of San Antonio, Texas – exploits the dense network of blood vessels on the scalp that carries blood to the brain. The device consists of two nylon sheets that fit around the head, one on top of the other, with small perforations in the layer closest to the skin. When cold air is blown between the two sheets, these perforations allow it to penetrate to the skin at regular intervals across the scalp, cooling the blood vessels. “It’s a bit like a hairdryer hood – it doesn’t cover the face and one lies with one’s head inside it,” says Harris. In tests on volunteers, the hood was able to cool the brain by almost 1 °C per hour – a similar rate to whole-body cooling methods (British Journal of Anaesthesia, DOI: 10.1093/bja/aem405). To produce an even more rapid change in brain temperature, though, other researchers are developing techniques to cool the brain from within the body, by chilling the blood before it reaches the brain. The nose provides an ideal

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Technology

route for this, since it evolved partly for heat exchange, says Allan Rozenberg of BeneChill in San Diego, California. “The nasal cavity is filled with a mass of blood vessels that warm incoming air,” he says. “Arteries carrying blood to the brain pass in close proximity to this mesh of capillaries, so cooling the nasal cavity also cools the blood that reaches the brain.” So BeneChill has developed a system called RhinoChill, which sprays a fine mist of perfluorocarbon droplets deep within the nasal cavity via two tubes inserted through the nostrils. Perfluorocarbon was chosen because it evaporates rapidly, cooling the walls of the nasal cavity, and a steady stream of oxygen further accelerates the evaporation. “If you touch washing that’s drying in the breeze, it feels cold because of the rapid evaporation. This has www.newscientist.com

CHILLED BRAINS Heart attacks and strokes can slash the supply of oxygen to the brain. Targeted cooling slows the brain cells’ metabolism, reducing their demand for oxygen and so protecting them in the short term. Here are two techniques

Icy slurry passed into lungs through a tube CAROTID ARTERY

A coolant is sprayed into the nasal cavity. Blood passing close by is cooled as it reaches the brain HEART

a similar effect,” says Rozenberg. Studies on animals suggest the device can cool the brain by as much as 2.4 °C an hour. Two clinical trials on cardiac arrest and stroke victims are under way, but healthy volunteers who tested early prototypes that used chilled saline solution responded positively, says Rozenberg: “At very cold temperatures some people got ‘ice cream headaches’,” but with a solution at about 10 °C, the recipients found it “refreshing”. Cooling blood from the lungs could also be used to chill the brain, since the carotid arteries lead directly from the chest to the head. A team from the Argonne National Laboratory in Illinois are attempting to achieve this by squirting a small amount of icy slurry into the entrance to the

The ice slurry can cool the brain by 4 °C – the safe limit before damage is risked – in less than 15 minutes, says Kasza, who has so far tested the technique on pigs. His team is investigating whether their icy slurry could also be applied to the kidneys –Vulnerable moment for the brain– (see picture, bottom left) and the heart during invasive surgery, to prevent damage to the organs lungs via a narrow tube passed when blood flow is suspended for down the windpipe. Once the the operation. brain has cooled to a suitable One of the main advantages of temperature, the melted ice is all the new techniques is that they simply sucked back out again are simple enough to apply before using the same tube – the same or immediately after resuscitation process used to remove water following a heart attack – from the lungs of someone minimising the delay between who has nearly drowned. the heart malfunction and cooling The difficulty, according to the brain. “A paramedic could team member Ken Kasza, was deliver the slurry,” says Kasza. ensuring the icy particles didn’t What’s more, a recent study start to snowball within the in pigs suggests that immediate narrow tube used to deliver the cooling with the RhinoChill device, slurry, making it stick like a thick besides reducing brain damage, milkshake in a straw. To prevent could also improve the chances of this, the team mixed the ice success of the resuscitation itself, particles in a slightly saline although it is not yet certain why solution that melted their rough edges until they were smooth and this is. Sixteen pigs were given a heart attack, and then left for round. “The particles just slip by 15 minutes before CPR was applied one another and don’t form an to start their hearts again. Of the entangled mass,” says Kasza. eight pigs cooled using the RhinoChill system during CPR, six survived, compared with just two of the eight who were left unchilled

“The use of therapeutic cooling in hospitals should radically improve patient outcomes” www.newscientist.com

Carotid artery lies next to the chilled lung, so the blood is cooled before it flows to the brain LUNG

(Resuscitation, DOI: 10.1016/ j.resuscitation.2008.03.087). Rapid application of such techniques could be particularly good news for stroke victims. “Clot-busting drugs can only be administered after diagnosis and brain scans in the hospital,” says Andrews. “But applying therapeutic cooling at the scene of the stroke could lengthen the time window in which the drugs are effective – before too much damage has occurred,” he says. Richard Lyon from the Royal Infirmary of Edinburgh, who is investigating the mechanisms behind therapeutic hypothermia, says it is not yet certain that immediate cooling at the scene of the cardiac arrest does significantly reduce brain damage compared with cooling applied hours later, since there have been conflicting studies. But in any case, he says, more widespread use of therapeutic cooling within hospitals should radically improve patient outcomes. “Current research shows that therapeutic cooling saves a life for every seven people it is applied to, and prevents significant brain damage in one person in every six,” he says. “This could be a real revolution in resuscitative care.” ● 10 Janury 2009 | NewScientist | 21

Technology Budget digital X-rays and how to make them

X-RAY READ-OUTS MADE EASY ELECTRODE

SCANNER

AMORPHOUS SELENIUM LIQUID CRYSTAL TRANSPARENT ELECTRODE

X-RAYS SCREEN LIGHT SOURCE SCANNER LIGHT SENSOR

A LOW-COST way of recording X-ray images electronically could make digital X-rays scanners affordable in the developing world. The method can produce high-resolution digital X-rays for one-tenth of the usual cost. Digital X-ray machines are prized because the images they produce are simple to analyse, manipulate and store. Most of them work by using a layer of amorphous selenium to convert the X-rays into electric charge. This “charge image” is then recorded using an array of transistors and other electronic components, akin to those used in some digital cameras. However, the machines are expensive because these arrays have to be large: X-rays cannot be easily focused, so X-ray machines work by recording the shadow of

Modelling bacterial fights for safer salami

A COMPUTER model of the battles between bacterial colonies could lead to salamis that are safer to eat and have longer shelf lives. The model could also help food scientists devise new ways to tackle the growth of dangerous bacteria in food. The bacterium Listeria monocytogenes is a leading source 22 | NewScientist | 10 January 2009

X-RAYS

– + – + – +

As X-rays hit the selenium layer, a charge is generated which causes the adjacent section of liquid crystal to turn transparent. An off-theshelf digital scanner can read off the resulting image

an object rather than a focused image. That means the recording medium, be it an electronic imager or conventional X-ray film, must be at least the same size as the object being scanned. Digitally imaging a human lung, for example, requires an array up to 40 centimetres square with 10 million pixels, which costs as much as $200,000. This puts them well out of reach of most hospitals in the developing world. A new device developed by John Rowlands and colleagues

at the University of Toronto in Ontario, Canada, could slash the cost of high-resolution digital X-rays. This low-cost alternative, which Rowlands calls the “X-ray light valve” consists of a layer of liquid crystal – which is opaque or transparent depending on whether an electric charge is present – covered with a layer of amorphous selenium. These layers are sandwiched between a pair of electrodes which generate an electric field across them. When an X-ray is taken, the

of food-borne disease in meats and other products. To understand how it grows in food, scientists often turn to computer models which describe how bacteria reproduce given a source of food and variables such as temperature, pH and humidity. Unfortunately, these models ignore the competition that L. monocytogenes faces from other bacterial species, says food safety specialist Alessandro Giuffrida at the University of Messina in Italy. He and colleagues have now developed a new model for bacterial growth that includes both competition and environmental influences. The Italian team has focused on the way bacteria grows in traditional Sicilian salami during the fermentation stage of its preparation – a period of curing in which L. monocytogenes, if

present, competes with a population of harmless lactic acid bacteria. The new model simulates this competition for resources as well as the effects of fluctuations in environmental factors such as temperature and accurately

“Controlling bacterial battles could give food a longer shelf life” reproduces experimental data on the growth of L. monocytogenes. The model could be useful for devising ways to control the bacterial growth during the fermentation process. The model suggests that fluctuations of temperature, pH or humidity can be used to limit bacterial growth. In the fermentation

rays that hit the selenium layer generate a charge which is drawn towards the liquid crystal by the electric field. This makes the liquid crystal transparent at those locations. The overall pattern of transparency and opacity can be read off the liquid crystal layer using a light-based digital scanner (see diagram) and presented as a digital image. “We used an off-the-shelf light scanner and the X-ray images looked beautiful,” says Rowlands. After recording the image, the liquid crystal is reset by an electric field that restores its opacity. Robert Street, an X-ray imaging expert at the Palo Alto Research Center in California, is intrigued. He reckons the X-ray light valve should be relatively cheap to fabricate. Richard Lanza, an expert in X-ray imaging technology at the Massachusetts Institute of Technology, says the idea is significant because it separates the read-out system from the X-ray mechanism. “Two-thirds of the people in the world will never have a chest X-ray to diagnose a life-threatening illness such as tuberculosis,” he says, so cutting the cost of digital X-ray machines in this way could make a big difference. Saswato Das ●

stage, greater fluctuations in these conditions led to slower growth of L. monocytogenes although the researchers have yet to work out why. So controlling these bacterial battles could produce food with a longer shelf life. The work will be published in the journal European Food Research and Technology. Software is on the market for predicting the shelf life of various foods based on the growth rates of single species of bacteria, but the ability to model two species is a step towards better prediction. “This is the first detailed look at the interplay of environmental noise and interactions between bacterial species,” says Fabio Marchesoni at the University of Perugia. “It’s an important advance in predictive microbiology.” Mark Buchanan ● www.newscientist.com

Cover story |

Resurrection There’s no chance of bringing back the dinosaurs, but other extinct beasts could one day rise again. Henry Nicholls looks at the most likely candidates

BRYAN CHRISTIE

●

THE recipe for making any creature is written in its DNA. So last November, when geneticists published the near-complete DNA sequence of the long-extinct woolly mammoth, there was much speculation about whether we could bring this behemoth back to life. Creating a living, breathing creature from a genome sequence that exists only in a computer’s memory is not possible right now. But someone someday is sure to try it, predicts Stephan Schuster, a molecular biologist at Pennsylvania State University, University Park, and a driving force behind the mammoth genome project. So besides the mammoth, what other extinct beasts might we coax back to life? Well, it is only going to be possible with creatures for which we can retrieve a complete genome sequence. Without one, there is no chance. And usually when a creature dies, the DNA in any flesh left untouched is soon destroyed as it is attacked by sunshine and bacteria. There are, however, some circumstances in which DNA can be preserved. If your specimen froze to death in an icy wasteland such as Siberia, or snuffed it in a dark cave or a really dry region, for instance, then the probability of finding some intact stretches of DNA is much higher. Even in ideal conditions, though, no genetic information is likely to survive more than a million years – so dinosaurs are out – and only much younger remains are likely to yield good-quality DNA. “It’s really only worth studying specimens that are less than 100,000 years old,” says Schuster. The genomes of several extinct species besides

24 | NewScientist | 10 January 2009

the mammoth are already being sequenced, but turning these into living creatures will not be easy (see “Revival recipe”, page 26). “It’s hard to say that something will never ever be possible,” says Svante Pääbo of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, “but it would require technologies so far removed from what we currently have that I cannot imagine how it would be done.” But then 50 years ago, who would have believed we would now be able to read the instructions for making humans, fix inherited diseases, clone mammals and be close to creating artificial life? Assuming that we will develop the necessary technology, we have selected 10 extinct creatures that might one day be resurrected. Our choice is based not just on feasibility, but also on each animal’s “megafaunal charisma” – just how exciting the prospect of resurrecting these animals is. Of course, bringing extinct creatures back to life raises a whole host of practical problems, such as where they will live, but let’s not spoil the fun...

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Park

Neanderthal (Homo neanderthalensis)

Extinct: ~25,000 years ago DNA preservation: Suitable surrogate: A draft sequence of the Neanderthal genome should be published sometime this year. “To have a reasonable-quality genome, say comparable to the chimpanzee, will then be another two years of work or so,” says Svante Pääbo of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. While he and his colleagues hope the genome will offer unique insights into the differences between us humans and our mysterious cousins, there is speculation it could also be used to resurrect the Neanderthal. Because of our very close shared ancestry, humans would make ideal egg donors and surrogate mothers. However, while Soviet scientists might once have tried to create a human-ape hybrid, today it is hard to imagine even the most crazed of mad scientists entering such taboo territory. “I find the idea of resurrecting the Neanderthal so ridiculous that any speculation on surrogate mothers is superfluous,” says Pääbo. At most, researchers might replace some human genes with the Neanderthal versions in cells growing in a dish to see what the effect is, he says.

Short-faced bear (Arctodus simus)

Extinct: ~11,000 years ago DNA preservation: Suitable surrogate:

Sabre-toothed tiger (Smilodon fatalis)

Extinct: ~10,000 years ago DNA preservation: Suitable surrogate: This fabled beast with its extraordinary canines would be a sight to behold. There are some spectacularly preserved sabretoothed specimens from the La Brea tar pits in Los Angeles, but the tar makes

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extracting DNA tricky, so nobody has been able to isolate decent sequences. However, there are also some permafrostpreserved specimens that might be a better source of DNA. If we could obtain a genome, a close living relative of the sabre-tooth, the African lion, should be a good egg donor and surrogate mother. Californians, beware!

This towering beast would dwarf the world’s largest living land carnivore, the polar bear. The short-faced bear may have been a third taller than the polar bear when standing upright, and it weighed up to a tonne. Recovering its DNA should be possible as there are specimens encased in permafrost. The short-faced’s closest living relative is the spectacled bear of South America. The two species parted evolutionary company only around 5 million years ago, but unfortunately, at just a tenth the body mass of the short-faced bear, the spectacled bear is unlikely to be a particularly good surrogate.

10 January 2009 | NewScientist | 25

Revival recipe YOU WILL NEED: ● Well-preserved DNA ● Several billion DNA building blocks ● A suitable surrogate species ● Some seriously advanced technology HERE’S WHAT TO DO… 1. Extract the DNA from your extinct species, sequence the fragments and assemble to obtain a complete genome. REALITY CHECK: genome sequences from extinct animals are likely to be riddled with lethal errors.

3. Package the chromosomes up into an artificial nucleus and pop it in an egg collected from your suitable surrogate species. This should then develop into an embryo, which will be a clone of a long-dead animal. REALITY CHECK: finding compatible species, let alone extracting eggs from them, could be a huge problem. Plus, no one has yet managed to clone birds or reptiles.

BRYAN CHRISTIE

2. Now take your DNA building blocks and recreate the DNA of your extinct beast, in the correct number of chromosomes. REALITY CHECK: it is not yet possible to make such long DNA molecules from scratch, but we should be able to one day.

Tasmanian tiger

4. Grow a baby animal from the embryo. For mammals, implant the embryo in the womb of a compatible surrogate mother. For a reptile or bird, incubate embryo using yet-to-be-developed techniques. For an amphibian or fish where fertilisation takes place outside the body, just sit back and watch. REALITY CHECK: compatible surrogate mothers may not exist for many extinct mammals.

26 | NewScientist | 10 January 2009

Extinct: 1936 DNA preservation: Suitable surrogate:

THE NATURAL HISTORY MUSEUM

HOW TO CHEAT: Rather than synthesising the entire genome from scratch, you could take the DNA of a closely related living species and modify it to be more like that of the extinct species you are aiming for. REALITY CHECK: some living species have already been made superficially more like extinct ones, but with today’s knowledge and technology they remain far from the real thing.

(Thylacinus cynocephalus)

The last Tasmanian tiger or thylacine – an individual known as Benjamin – died in Hobart Zoo in 1936. The existence of various preserved tissues less than a century old means geneticists should be able to get good-quality DNA and produce a complete sequence of the thylacine genome before too long. When it comes to resurrection, marsupials like the thylacine might be easier than most other mammals. Pregnancy in marsupials typically lasts just weeks, and a simple placenta forms only briefly, meaning there might be less risk of incompatibility between an embryo and a surrogate mother of another species. For the thylacine, the surrogate would be the Tasmanian devil. After birth, the fetus could be raised on milk in an artificial pouch.

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Glyptodon (Doedicurus clavicaudatus) Extinct: ~11,000 years ago DNA preservation: Suitable surrogate:

Dodo

The Volkswagen Beetle-sized “colossal” armadillo, with its spiky, club-like tail, once rumbled across the South American countryside, and some might fancy seeing it do so again. Because there are no frozen glyptodons, obtaining usable DNA will depend on finding well-preserved remains in a cool, dry cave. Beyond that, there is an even bigger problem: the most suitable species to act as a host for a developing glyptodon embryo would be the far smaller 30-kilogram “giant” armadillo. The difference in size means it would struggle to carry its extinct relative to term.

(Raphus cucullatus)

THE NATURAL HISTORY MUSEUM

Extinct: ~AD 1690 DNA preservation: Suitable surrogate: In 2002, geneticists at the University of Oxford got permission to cut into the world’s best-preserved dodo specimen, a foot bone – complete with skin and feathers – held under lock and key at the university’s Museum of Natural History. “It was one of the scariest things I’ve had to do,” recalls Beth Shapiro, an ancient DNA specialist now at Pennsylvania State University. This yielded minute fragments of dodo mitochondrial DNA but nothing more. Since then, no other specimen has yielded even a whiff of dodo DNA, but there is still hope that some will one day be found. “We’re still looking,” says Shapiro. If one turns up and a genome sequence could be produced from it, it would then be down to pigeons to help bring their famous cousin back from the dead.

Woolly rhinoceros (Coelodonta antiquitatis)

MAURICIO ANTON

Extinct: ~10,000 years ago DNA preservation: Suitable surrogate:

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Resurrecting the woolly rhino has lots going for it. As with the mammoth, there are plenty of specimens preserved in permafrost, and the availability of hair, horns and hooves is a big plus. These tissues can be cleaned up with shampoo and bleach to remove contaminant DNA from microbes and fungi before using enzymes to release an abundance of near-pure rhino DNA. This makes it likely that geneticists will publish the complete genome of this hirsute beast before long. However, although the woolly rhino has close living relatives that might make suitable surrogates, all contemporary rhino species are themselves on the brink of extinction. As long as this remains the case, resurrecting a woolly rhino is unlikely to be a top priority.

10 January 2009 | NewScientist | 27

Irish elk

Giant ground sloth

(Megaloceros giganteus)

(Megatherium americanum)

THE NATURAL HISTORY MUSEUM

Extinct: ~8000 years ago DNA preservation: Suitable surrogate:

Extinct: ~7700 years ago DNA preservation: Suitable surrogate:

(Dinornis robustus)

There is plenty of moa DNA to be found in well-preserved bones and even eggs in caves across New Zealand, so obtaining a moa genome should be doable. But which one? It would be tempting to go for the massive

28 | NewScientist | 10 January 2009

Gorilla (Gorilla gorilla)

Extinct: Almost DNA preservation: Suitable surrogate:

Moa

Extinct: ~AD 1500 DNA preservation: Suitable surrogate:

BRYAN CHRISTIE

This giant stood around 6 metres tall and is estimated to have weighed a whopping 4 tonnes. The sloth’s relatively recent extinction means that several specimens have been found with hair, an excellent source of DNA. So are we likely to see the giant sloth genome published? “Absolutely,” says Hendrik Poinar of MacMaster University in Canada, who has extracted giant ground sloth DNA from fossilised dung deposited some 30,000 years ago. The difficulty for anyone intent on resurrection would be the lack of a suitable surrogate. Its closest living relative – the three-toed tree sloth – is tiny by comparison. It might be able to provide eggs with which to create a giant ground sloth embryo, but the fetus would quickly outgrow its surrogate mother.

Deer-hunting enthusiasts would give almost anything for a chance to stalk this Pleistocene giant, once found across Europe. A typical male Megaloceros stood more than 2 metres tall at the shoulder and sported antlers 4 metres wide. It is actually a deer rather than an elk, and its closest living relative is the much smaller fallow deer, the two species having parted evolutionary company around 10 million years ago. The gulf between the two species means it is hard to see how a complete genome could be converted into a living, breathing animal.

Dinornis robustus, which stood more than 3 metres tall, but starting with the more modestly sized Megalapteryx didinus might make more sense. Although only distantly related to ostriches, it might be possible to boot up the moa genome in an ostrich egg. As no bird has yet been cloned, however, perhaps the most feasible approach would be to engineer an ostrich embryo to be moa-like.

The first species to be brought back from extinction will most likely be one that is alive today. Conservationists are freezing tissue samples from some threatened species, so clones could be created with the help of a closely related surrogate species if a suitable habitat becomes available. For gorillas, the surrogate would be the chimpanzee. ● Henry Nicholls is a science writer based in London, and author of Lonesome George (Macmillan, 2006) www.newscientist.com

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Immoral advances When research raises deeply felt objections, it’s not enough just to dismiss them as “irrational”, says Dan Jones

●

A focused campaign on embryo research changed attitudes in the UK www.newscientist.com

WHAT would our forebears have made of test-tube babies, microwave ovens, organ transplants, CCTV and iPhones? Could they have believed that one day people might jet to another continent for a weekend break, meet their future spouse on the internet, have their genome sequenced and live to a private soundtrack from an MP3 player? Science and technology have changed our world dramatically, and, for the most part, we take them in our stride. Nevertheless, there are certain innovations that many people find unpalatable. Leaving aside special-interest attitudes such as the fundamentalist Christian denial of evolution, many controversies over scientific

advances are based on ethical concerns. In the past, the main areas of contention have included nuclear weapons, eugenics and experiments on animals, but in recent years the list of “immoral” research areas has grown exponentially. In particular, reproductive biology and medicine have become ripe for moral outrage: think cloning, designer babies, stem-cell research, human-animal hybrids, and so on. Other troublesome areas include nanotechnology, synthetic biology, genomics and genetically modified organisms or so-called “Frankenfoods”. To many scientists, moral objections to their work are not valid: science, by definition, is morally neutral, so any moral judgement 10 January 2009 | NewScientist | 29

on it simply reflects scientific illiteracy. That, however, is an abdication of responsibility. Some moral reactions are irrational, but if scientists are serious about tackling them – and the bad decisions, harm, suffering and barriers to progress that flow from them – they need to understand a little more and condemn a little less.

So what are the snares people step into when trying to work their way through the moral dimension of science? Some of the most common are to do with the simple rules of thumb, or heuristics, that we use to make sense of the world. Heuristics can be thought of as tools in our mental toolbox that have evolved over millennia to help us make fast decisions in complex situations or where information may be limited, such as when choosing between various options or making everyday predictions. A particularly pervasive example in the moral domain is the injunction “Do not play God” or, in more secular terms, “Do not tamper with nature”. These axioms make intuitive good sense but have led to some of the most bitter clashes between science and morality (see “Some things are sacred”). Take our attitudes to food production. Cass Sunstein, an adviser to Barack Obama and the Felix Frankfurter Professor of Law at Harvard University, points out that manufacturers go to great lengths to portray foods as natural, and that consumers attach considerable importance to these assurances. He argues that much of the public opposition to genetically modified organisms is founded on moral heuristics: GMOs are seen as unnatural and therefore morally unacceptable. This is an example of the naturalistic fallacy, a wellknown pitfall in rational thought. More than a century ago, British philosopher John Stuart Mill wrote an essay called On Nature in which he argued that the term “natural” is “one of the most copious sources of false taste, false philosophy, false morality, and even bad law”. This is certainly the case with food, says Sunstein, where our tendency to see “natural” 30 | NewScientist | 10 January 2009

RODRIGO BALEIA/WPN

Do not play God

foods as safer leads us to underestimate the cancer-causing potential of some such products and overestimate the dangers of pesticides, cloned livestock and GMOs (Behavioral and Brain Sciences, vol 28, p 531). The problem with using moral heuristics to judge science is even starker in some popular perceptions of reproductive technologies. “Designer” babies are a case in point. IVF combined with genetic testing makes it possible to screen the cells of an embryo for specific gene variants before it is implanted into the womb. This preimplantation genetic diagnosis is primarily used to filter out embryos with genes for heritable diseases, but in future it could be used to choose babies with desired traits, such as tallness or a particular eye colour, and perhaps even physical prowess, intelligence and aspects of personality. To take it to the extreme, parents of the future

may want to add new genes to the embryo to rig nature’s genetic lottery. Many people view this as the ultimate hubris of scientists and parents wishing to play God. Lewis Wolpert, a developmental biologist at University College London, disagrees. “Instead of worrying about embryos, we should be worrying about children,” he says. Statistics compiled by the UK’s National Society for the Prevention of Cruelty to Children suggest that up to a quarter of children suffer from some sort of emotional, physical or sexual abuse. “You deny people the right to modify the child, but if they’re going to be the most terrible parents in the world you say, ‘All right, go ahead.’ This is absolute moral confusion,” Wolpert says. Wolpert believes that knowledge, not a moral heuristic, is the best guide to thinking about the desirability of scientific or technological progress. So while he doesn’t www.newscientist.com

“GMOs are seen as unnatural and therefore morally unacceptable”

ROMEO RANDRO/REUTERS

oppose “designer” babies on ethical grounds, he doesn’t think there should be a genetic freefor-all either, because his own expertise has persuaded him this is an area where scientists should tread carefully. “You might think you know what you’re doing when you put in new genes, but it’s very tricky, and you’re likely to produce abnormalities,” he says. “I think it’s a safety issue, not an ethical issue.” As societies become more scientifically literate, scientific developments may well be judged more from a position of knowledge and less on the basis of intuitive responses driven by moral heuristics. However, there is another serious obstacle to the rational approach: our emotions, and especially the most morally loaded of emotions, disgust. In the wake of the creation of Dolly the cloned sheep, bioethicist Leon Kass of the University of Chicago argued that the visceral feeling which many people have in response to the most contentious scientific advances embodies a kind of wisdom that is beyond the power of reason to articulate (The New Republic, vol 216, p 17). Many people are guided by this supposed “wisdom of repugnance”. Arthur Caplan, a bioethicist at the

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Some things are sacred

Should we legalise a market in scarce donor organs such as kidneys?

Certain issues can seem so clearly right or wrong that they are almost immune to rational consideration: for instance, when others seem to have put a value on something we deem sacred. Last August there was a public outcry in the UK when it emerged that the National Institute for Health and Clinical Excellence – which is charged with undertaking cost-benefit analyses of treatments for the National Health Service – had advised against the use of four drugs that could prolong the lives of people with kidney cancer, on the grounds that they were too expensive. The fact that a monetary value was being placed on human life – in this case, £24,000 a year – was considered a monstrously cold calculus. The advice has now been reversed. Psychologist Philip Tetlock from the University of California, Berkeley, has been investigating this phenomenon. His research shows that people generally treat trade-offs between “sacred” values (a life, say) and “secular” values (such as money or efficiency) as morally outrageous, even taboo (Trends in Cognitive Science, vol 7, p 320). However, his study of attitudes to organ donation also suggests ways that we can reframe such issues to help us think about them more clearly. Worldwide, there is a shortage of human organs for lifesaving transplants. One solution recently debated in the UK and Australia is to change the law from an opt-in to a “presumed consent” system, under which everyone is treated as a potential organ donor unless they actively opt out (New Scientist, 13 September 2008, p 11). Another even more contentious answer is to set up regulated markets

for buying and selling organs. For many, it is a gross violation of human dignity and sanctity to treat body parts as mere commodities, to be traded like pork bellies or oil. In Tetlock’s study, most people were initially appalled by the idea, but 40 per cent of objectors toned down their opposition after hearing two arguments rationalising the proposal. The first was simply that such transactions are the best way to solve the organ shortfall and save lives that would otherwise be lost. The second made it clear that measures would be put in place to help the poor, so they would not be driven to sell their organs out of desperation, and would have access to replacement organs. ACCEPTABLE TRADE-OFFS Tetlock suggests that these points transformed what was seen as a taboo trade-off (the sacred quality of human body parts for the secular commodity of money) into something more palatable. The first argument makes sacred the secular side of the trade-off, replacing money with the sacred value of saving lives. This allows people to see the organ market as what Tetlock calls a “tragic” trade-off, in which competing sacred values are in the balance. The second argument pits two secular concerns against one another in a “routine” trade-off: providing access to needed organs on the one hand, and preventing exploitation and inequalities in access to healthcare on the other. People are more willing to think about both routine and tragic trade-offs than taboo ones, says Tetlock, so this kind of reframing could be widely applied to help the public assess these sorts of difficult issues.

10 January 2009 | NewScientist | 31

University of Pennsylvania in Philadelphia, is not one of them. He has coined the more disparaging term “yuk response” to describe this reaction, and believes we should challenge the idea that repugnance is a reliable moral guide and the ultimate arbiter. “You begin the process by questioning the validity of the yuk response, calling it into doubt and pointing out that the yuk meter may be untrustworthy,” says Caplan. Then it becomes possible to start exploring the reasons and justifications for people’s initial intuitions of right or wrong, and see how they stand up to scrutiny.

Beyond the yuk factor The power of this approach can be seen in the changing attitudes of the British public to the creation of human-animal hybrids, according to Fiona Fox, director of the Science Media Centre at the Royal Institution of Great Britain in London. This research involves removing DNA from an animal egg, substituting human DNA and then allowing the embryo to develop for 14 days before harvesting stem cells for research into diseases such as Parkinson’s and diabetes. Two years ago, public consultations revealed widespread moral unease about such work, driven primarily by the yuk response. So in December 2006, the British government issued a draft bill that would make it illegal. However, the scientists involved believed this was a bad decision that would close

a promising area of research, and decided to challenge the issue head-on. “For two years scientists repeatedly briefed journalists and explained to the public what this research involves and why they want to do it, all without over-hyping the science,” says Fox, who helped arrange many of these meetings. Gradually public perceptions of the research changed from repugnance based on ill-informed notions about chimeras to an understanding of the lifesaving aims of the work. Earlier this year the bill was changed to allow the creation of human-animal hybrids and now looks set to pass into law. “Opinion polls say the public now accepts this research and parliament has voted for it. It’s a fantastic story,” says Fox, and one to which scientists who work in ethically contentious fields should pay heed. Persuading people to rationalise their feelings about developments in science may be a good way to get a conversation going between researchers and the public, but it also exposes a crucial difference – one that goes beyond morality – in the way the two groups tend to see the world. It is only human to fear the unknown. We want firm assurances that everything will be OK, and are used to getting these from politicians and other public figures. But scientists spend their lives considering possibilities, risks and precise statistics, and so tend never to say “never”. This can lead to very different perceptions of a situation. A fascinating instance of this

DAVID MCNEW/GETTY

“Parents may one day want to add genes to the embryo to rig nature’s genetic lottery”

happened last September when the Large Hadron Collider was switched on at CERN. There was speculation that the new accelerator might create a black hole that could destroy the world, and this so terrified several groups of people that they attempted to use the law to prevent the experiments going ahead. Many physicists said it was all nonsense, but the few who did accept there might be a minute possibility of catastrophe seemed quite sanguine about it, recognising that we blithely accept everyday situations that are far more risky. Cynics have argued that the LHC episode was just a good publicity stunt. Nevertheless,

Tomorrow’s moral minefields MIND READING Progress in neuroscience could usher in an era in which brain imaging reveals our deepest desires and secrets. The ability to peer inside our heads to discover when we are lying and whether we prefer one product, or perhaps even one sex or racial group, to another, raises profound worries about privacy as well as practical issues about how such technologies might be used in law courts or by marketing companies (Trends in Cognitive Sciences, vol 9, p 34).

32 | NewScientist | 10 January 2009

ARTIFICIAL REPRODUCTION Traditional ideas about procreation will be overturned if biologists succeed in creating artificial sperm and eggs, or even artificial wombs in which fetuses can grow outside of human mothers (Nature, vol 454, p 260). Some people will see these innovations in reproductive biology as welcome technological advances to help single or infertile people who want to have children. Others, however, are likely to view them as immoral attempts to play God.

“CURING” CRIMINALITY The spectre of “fixing broken brains” looms as we gain more power to manipulate cognitive states with drugs and implants (Trends in Cognitive Sciences, vol 9, p 34). Using brain “enhancers” to treat psychiatric patients is contentious enough, but what if we could alter the thinking of criminals to “cure” their errant behaviour? Would that be an unconscionable infringement of individual liberty or a pragmatic solution to a social problem?

www.newscientist.com

fear of the unknown does shape public opinion about scientific developments, and in new fields of research where uncertainty is high, it can be enormously powerful. Critics of nanotechnology, for example, have conjured up the image of out-of-control self-replicating nanomachines greedily eating up the world as they produce more copies of themselves – the dystopian “grey goo” scenario. Similarly, some detractors of advances in synthetic biology fear that newly created life forms could produce a comparable “green goo” meltdown. Such speculations may be fanciful, but if they appeal to the public imagination they can be very difficult to dispel. Nevertheless, bioethicists Erik Parens, Josephine Johnston and Jacob Moses from the Hastings Center in New York suggest that there may not be quite as much unknown to fear as these scenarios suggest. They have recently argued that while new disciplines such as synthetic biology seem to present new concerns, in fact they often raise familiar ethical issues (Science, vol 321, p 1449). “We risk reinventing the ethical wheel with each new development, and squandering scarce resources,” says Parens. Johnston also believes we must accept that often there are no definitive answers to these divisive problems. “We should engage in extended discussion in which we try to understand the very different perspectives www.newscientist.com

out there rather than adjudicating the one correct position,” she says. While this is already happening in some quarters, as the public debate over human-animal hybrids in the UK testifies, Caplan for one thinks much more could be done. “I remain unpersuaded that the scientific community takes seriously its responsibility to get into this,” he says. “They don’t care much what society thinks, so long as the money keeps rolling in.” Wolpert believes part of the problem is that it is not clear what scientists should do. “Say you put on a whole series of television programmes about some topic. There’s just no research to see whether this changes people’s minds.” =EJ
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He suspects that face-to-face meetings between scientists and the public could be crucial. As an example, he cites a recent public vote on a proposal to restrict the use of GMOs in Switzerland. Scientists gave a series of impersonal public lectures opposing the measure, with little effect. “They were a total waste of time,” says Wolpert. “It was direct contact with small groups of people that made all the difference – the public see that the researchers aren’t Frankenstein.” Meeting the human face of science helps assure people that researchers are not an army of moral monsters and should be allowed to continue working with GMOs. Even if openness, accountability and mutual understanding do not create consensus on the thorniest ethical issues, at least they can expose instances where our judgements are based on irrational thinking such as moral heuristics, feelings of disgust or fear of the unknown. The more we understand why we demonise certain scientific advances, the better we will be able to decide whether some areas of research are so sensitive they should always remain off limits to science (see “Tomorrow’s moral minefields”). For scientists themselves, this is perhaps the most contentious issue. “It is very dangerous to try picking and choosing which truths we dare acknowledge,” says Nick Bostrom, director of the Future of Humanity Institute at the University of Oxford. “Such a practice destroys intellectual integrity, which is a fragile yet tremendously precious quality – one that we urgently need to grow if we are to handle wisely the existential challenges of the 21st century.” Many researchers will share Bostrom’s robust view, yet even he acknowledges that some research projects may be harmful. We must all take part in the debate about what these might be. The onward march of science and technology is bound to continue to raise ethical issues. Only by scrutinising them can we make better decisions about how that progress shapes humanity’s future. ● Dan Jones is a freelance writer based in Brighton, UK 10 January 2009 | NewScientist | 33

Can we undo the mess we’re making of the global climate by scrubbing CO2 out of the atmosphere, ask Robert Kunzig and Wallace Broecker

●

THREE hundred and eighty-five parts per million: that’s how much carbon dioxide there is in the atmosphere now. Just 100 parts per million more than before we started mucking things up, yet the Arctic ice cap is already melting, weather patterns are changing, and plants and animals are migrating towards the poles to find their comfort zones. We can’t go on like this. In fact, some climate scientists, notably James Hansen of NASA, say that 385 parts per million is too high and that we need not just to slow the increase in CO2 but to clean up the mess we’ve already made. Three hundred and eighty-five invisible, colourless needles for every million stalks in the haystack. What are the chances that we can find and remove them? Slim to none, according to many scientists and engineers. They say that removing CO2 from the air is a complete non-starter because it takes far too much energy. That hasn’t stopped a handful of researchers from trying. They argue that air capture is not only theoretically feasible, it will soon be a practical weapon against global warming. Above all, they argue, we can’t afford not to develop ways to scrub carbon from the atmosphere as a vital last line of defence. If Hansen is right and we’ve already gone past the point of no return, no amount of solar power or energy efficiency will save us. We need to take CO2 directly out of the atmosphere, and fast. Capturing CO2 gas is not difficult. In fact, in the near future we are likely to be extracting quantities of the stuff from the flue gases of power plants and factories, and stashing it deep underground. In 2005 a special committee of the Intergovernmental Panel on Climate Change concluded that this strategy – known as carbon capture and storage or CCS – is likely to have a key role in tackling climate change. An entire industry, well supported by governments and energy companies, has since sprung up to make CCS a reality. 34 | NewScientist | 10 January 2009

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Once CO2 gets out into the open air, however, capturing it gets trickier. Levels in the atmosphere are around 1/100th of its concentration in flue gases, and based on this the IPCC panel concluded that capturing CO2 directly out of the air was impractical in terms of the energy that would be required. Klaus Lackner of Columbia University in New York City begs to differ. A particle physicist by training, he has been pushing air capture for years. He has worked out the theoretical minimum energy required to remove CO2 from air, and says that the IPCC panel – of which he was a member – got its numbers wrong. “It takes more energy to extract CO2 from air than from flue gas, but the difference is quite small,” he says. Those calculations convinced Lackner that an air scrubber was a practical proposition, but they failed to convince his peers on the committee. To do that, he realised, he’d have to build one. Which is what he has done. In mid-2008 he and his colleague Allen Wright were granted patents on a scrubber made of a plastic that spontaneously grabs CO2 from the air. Their device collects just a few tens of kilograms of CO2 a day from air blowing through the gaps between vertical sheets of the plastic. But with two years’ work and, say, $20 million in venture capital – not easy to come by right now – Lackner says he could build a model that removes a tonne a day and would fit in a standard shipping container. Units like this might be of immediate interest to companies that have to buy in CO2, and Lackner suggests

“Millions of the devices

could eventually be built to suck CO2 out of the air and reverse global warming ”

that millions of them could eventually be deployed to suck CO2 from the atmosphere and help save us from global warming. Lackner isn’t the only one working on air capture. Lab-scale units have also been built by teams at the University of Calgary in Alberta, Canada, and at the Swiss Federal Institute of Technology (ETH) in Zurich.

No pipelines attached If interest in air capture is getting keener, it’s because the potential advantages are so great. For one thing, air scrubbers would capture CO2 from any source, big or small, including cars, planes and heating systems. These produce more than a third of global CO2 emissions but it is impractical to capture the gas at source from tailpipes or flues. What’s more, because CO2 emissions mix into the atmosphere quickly and levels are the same pretty much everywhere, air scrubbers could be placed directly over sequestration sites. In contrast, CO2 captured at power plants will often have to be sent through hundreds of kilometres of pipeline. As David Keith of the University of Calgary puts it, air capture is “decoupled from the rest of the energy economy”. Keith and his student Joshuah Stolaroff built their first air-capture prototype three years ago, using a version of the tried-andtested “spray towers” that remove sulphur dioxide from the smokestacks of coal-fired power plants. Like sulphur dioxide, CO2 is an acid gas that can be soaked up by a solution of the alkali sodium hydroxide. Keith and Stolaroff’s prototype is a 4-metre-high cylinder of heavy-duty cardboard lined with PVC. The air to be treated is blown in at the top, where it is sprayed with a fine shower of sodium hydroxide solution. This reacts with CO2 in the air to form droplets of sodium carbonate. A full-scale scrubber might resemble an aircraft hangar, with fans at one end blowing air through a mist of sodium hydroxide 10 January 2009 | NewScientist | 35

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from nozzles in the ceiling. Drains in the floor would collect the sodium carbonate solution. The system works, but it takes a whopping amount of energy. At the end of the process, the sodium carbonate needs to be turned back into sodium hydroxide, which is cheap but not so cheap that you could afford to use it only once. This requires a kiln heated to 900 °C. Keith thinks he could halve the energy needed and cut the overall cost of capturing CO2 and sequestering it to the vicinity of $100 per tonne (Environmental Science and Technology, vol 42, p 2728). That’s far more than polluters pay under the European Union emissions control scheme, which currently prices a tonne of CO2 at €15 (New Scientist, 19 April 2008, p 38). But it is perhaps not much more than the price will be once governments get serious about climate change. Keith accepts that air scrubbers are unlikely ever to be the most economical way to tackle global warming, but reckons we might be forced into using them anyway. “You still might end up doing it,” he says, 36 | NewScientist | 10 January 2009

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“because you get into crisis mode.” While Keith is busy adapting existing technology, other researchers are shooting for something more novel. At ETH Zurich, Aldo Steinfeld, whose main interest is in solar energy, became interested in air scrubbers after Lackner visited the institute to talk on the subject. “We decided we could do that using solar technology,” Steinfeld says.

Solar scrubber The ETH concept is a modified version of an energy-generating technology called concentrated solar power that has been blossoming lately in deserts around the world (New Scientist, 10 April 2004, p 26). Such power plants consist of fields of sun-tracking mirrors that focus sunlight to generate steam that drives a generator. “We remove the boiler,” explains Steinfeld. “We put our solar reactor there. In this we remove CO2 from the air.” Steinfeld’s reactor is a transparent tube filled with pellets of calcium oxide. In the

table-top version the tube is a few centimetres high and an arc lamp replaces the sun. As the light heats the tube and its contents to 400 °C, air mixed with a small amount of steam is pumped in at the bottom and up through the pellets. At this temperature, the calcium oxide reacts with CO2 to form calcium carbonate. “By the time the air leaves, there is no CO2,” says Steinfeld. “We go from 385 parts per million to practically zero.” In less than 15 minutes, the pellets are mostly converted to calcium carbonate. At that point, Steinfeld closes the intake valve and intensifies the light, raising the temperature in the reactor to 800 °C. This drives off the CO2 as a stream of pure gas, which can be sent for sequestering, and converts the calcium carbonate back into calcium oxide. The researchers have run their reactor through five cycles of absorption and release with no decline in performance. Steinfeld believes his device could be scaled up to take significant amounts of CO2 out of the atmosphere, though as yet he doesn’t know www.newscientist.com

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how much it would cost per tonne. Using sunlight to strip CO2 out of the air clearly has advantages over a kiln. But Lackner suggests that if you’re going to fill a desert with solar concentrators, it might make more environmental sense just to convert that sunlight into electricity. Lackner’s own strategy is to drastically reduce the amount of energy required to strip CO2 out of the air. He and his colleagues have experimented with various designs, but the heart of each is an ion exchange resin, a polymer impregnated with sodium hydroxide. The sodium ions are firmly

“At present emission

rates we would need 20 million tonne-a-day units just to absorb CO2 from transport” www.newscientist.com

attached to the polymer but the hydroxide is loose and easily displaced by CO2, which binds to the sodium to form sodium bicarbonate. The chemistry is essentially the same as in the Calgary device, says Lackner, but because of the enormous surface area of the resin sheets, the reaction goes much faster. The resin has a second major advantage: it changes state when it gets wet, reducing its affinity for CO2. “So we can drive the [absorbed] CO2 off just by adding moisture,” says Lackner. The Calgary and Zurich air scrubbers need temperatures of up to 900 °C to regenerate their CO2-absorbing material, but Lackner can do it at 40 °C. “We are dealing with extremely small amounts of energy,” he says. As yet, though, he hasn’t done a detailed analysis of how much it would cost per tonne of CO2. He does, however, think it will be cheap enough to open up commercial opportunities for his technology. Fruit and vegetable growers routinely enrich the air in their greenhouses with extra CO2 and can pay as much as $300 a tonne for the stuff. Lackner reckons an air scrubber attached directly to the greenhouse could beat that price.

Miniature greenhouse One of his demonstration devices is in fact a miniature greenhouse around a metre long. Attached to one end is a plastic tube containing the ion exchange resin, which absorbs CO2 from the air. When most of the sodium hydroxide in the resin has been converted to sodium bicarbonate, Lackner evacuates the tube and then allows it to refill with moist air from the greenhouse. This releases the CO2, which can then be flushed out into the greenhouse. The device generates around a kilogram of CO2 per day, which is converted into biomass by tomato plants inside the greenhouse. Oil companies also buy CO2 by the tonne to flush oil out of ageing fields, and Lackner

reckons that an air scrubber capable of capturing a tonne of CO2 a day could become commercially viable both for this market and for horticulture, even in the absence of government caps on carbon emissions. “We’d learn how to drive the price down, and we wouldn’t have to hold our breath for government regulations,” he says. “If the government decides to help us, that’s great. But we don’t have to wait for it.” What he is having to wait for at the moment is the venture capital required to build a tonne-a-day prototype. For lack of this investment, the small company he had helped found to commercialise his idea recently closed its doors. Using air capture to help tackle climate change faces an even bigger economic challenge. It will not take off until governments set a price on carbon that justifies the investment. But if and when that happens, a new and potentially vast market might open up: synthesising fuels out of thin air. “You capture CO2 and combine it with hydrogen to make fuel,” says Keith. Fuels made from air-captured CO2 would cause no net emissions, because the carbon they release would be have come from the air in the first place (New Scientist, 1 March 2008, p 32). Of course there is still the hope that it’s not too late and we can avert a climate crisis through a massive switch to solar, wind or nuclear power. But if not, air scrubbers could be the last-ditch lifeline. It would be a monumental undertaking. At present we would need some 20 million tonne-a-day units to absorb emissions from the transportation sector alone. But if things get desperate it just might come to that, says Keith. “Our grandkids will clean up the mess we made by sucking it out of the air.” ● Robert Kunzig is a writer based in Dijon, France, and Birmingham, Alabama. Wallace Broecker is a climate scientist at Columbia University in New York City. Their book, Fixing Climate, is published by Profile 10 January 2009 | NewScientist | 37

●

IT IS 1944, and there is a war on. In a joint army and air force headquarters somewhere in England, Major Parkinson must oil the administrative wheels of the fight against Nazi Germany. The stream of vital paperwork from on high is more like a flood, perpetually threatening to engulf him. Then disaster strikes. The chief of the base, the air vice-marshal, goes on leave. His deputy, an army colonel, falls sick. The colonel’s deputy, an air force wing commander, is called away on urgent business. Major Parkinson is left to soldier on alone. At that point, an odd thing happens – nothing at all. The paper flood ceases; the war goes on regardless. As Major Parkinson later mused: “There had never been anything to do. We’d just been making work for each other.” That feeling might be familiar to many working in large organisations, where decisions can seem to be bounced between layers of management in a whirl of consultation, circulation, deliberation and delegation. It led Major Parkinson – in civilian dress, C. Northcote Parkinson, naval historian, theorist of bureaucracy and humorist – to a seminal insight. This is “Parkinson’s law”, first published in an article of 1955, which states: work expands to fill the time available for its completion. Is there anything more to that “law” than just a cynical slogan? Physicists Peter Klimek, Rudolf Hanel and Stefan Thurner of the Medical University of Vienna in Austria think so. They have recreated mathematically just the kind of bureaucratic dynamics that Parkinson described anecdotally 50 years ago. Their findings put Parkinson’s observations on a scientific footing, but also make productive reading for anyone in charge of organising… well, anything. Parkinson based his ideas not just on his war experience, but also his historical research. Between 1914 and 1928, he noted, the number of administrators in the British Admiralty increased by almost 80 per cent, while the number of sailors they had to administer fell by a third, and the number of ships by two-thirds. Parkinson suggested a reason: in any hierarchical management structure, people in positions of authority need subordinates, and those extra bodies have to be occupied – regardless of how much there actually is to do. Parkinson was crystallising, with tongue half in cheek, classic work done by the German sociologist Max Weber in the early 20th century. Weber described the attributes of an ideal bureaucracy and possible “degenerating” influences – such as any system of promotion not based wholly on merit. Parkinson’s own analysis spawned other, more po-faced and politically charged critiques of public bureaucracies from economists such as 38 | NewScientist | 10 January 2009

The curse of the committee Work expands to fill the time available – and maths can help explain how and why, says Mark Buchanan

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William Niskanen, who served on US President Ronald Reagan’s Council of Economic Advisers. Niskanen theorised that bureaucracies grow because officials seek to increase the budgets they control and so boost their own salary, power and standing. He and other conservatives used such arguments to push for smaller government – but they could not give any supporting quantitative insight into the growth of bureaucracies. The new work aims to do just that. “Parkinson’s essays weren’t quantitative,” says Klimek, “but they’re so clear that it’s easy to cast them into specific mathematical models.” From a simple system of equations using quantities such as the promotion and dropout rates within a hierarchical body, a “phase diagram” can be computed to show what conditions breed ever greater bureaucracy. A high probability of promotion coupled with the hiring of more subordinates – the scenario Parkinson described – is unsurprisingly a recipe for particularly fast growth. Parkinson was also interested in other aspects of management dynamics, in particular the workings of committees. How many members can a committee have and still be effective? Parkinson’s own guess was based on the 700-year history of England’s

highest council of state – in its modern incarnation, the UK cabinet. Five times in succession between 1257 and 1955, this council grew from small beginnings to a membership of just over 20. Each time it reached that point, it was replaced by a new, smaller body, which began growing again. This was no coincidence, Parkinson argued: beyond about 20 members, groups become structurally unable to come to consensus. A look around the globe today, courtesy of data collected by the US Central Intelligence Agency, indicates that Parkinson might have been onto something. The highest executive bodies of most countries have between 13 and 20 members. “Cabinets are commonly constituted with memberships close to Parkinson’s limit,” says Thurner, “but not above it.” And that is not all, says Klimek: the size of the executive is also inversely correlated to measures of life expectancy, adult literacy, economic purchasing power and political stability. “The more members there are, the more likely a country is to be less stable politically, and less developed,” he says. Why should this be? To find out, the researchers constructed a simple network model of a committee. They grouped the nodes of the network – the committee

Would a bigger group do the job better – or worse?

Van Buren, Indiana (pop. 955) Town Council, July 21, 1999: (L to R) Michelle Sexton (Clerk, Treasurer), Tony Manry (President), Marvin Surber, Dean Baker. © Paul Shambroom 1999. From “Meetings” series. Pigmented inkjet on canvas with varnish, 33x66 inches

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members – in tightly knit clusters with a few further links between clusters tying the overall network together, reflecting the clumping tendencies of like-minded people known to exist in human interactions. To start off, each person in the network had one of two opposing opinions, represented as a 0 or a 1. At each time step in the model, each member would adopt the opinion held by the majority of their immediate neighbours. Such a process can have two outcomes: either the network will reach a consensus, with 0s or 1s throughout, or it will get stuck at an entrenched disagreement between two factions. A striking transition between these two possibilities emerged as the number of participants grew – around Parkinson’s magic number of 20. Groups with fewer than 20 members tend to reach agreement, whereas those larger than 20 generally splinter into subgroups that agree within themselves, but become frozen in permanent disagreement with each other. “With larger groups, there’s a combinatorial explosion in the number of ways to form factions,” says Thurner. Santo Fortunato, a physicist who works on complex networks at the Institute for Scientific Interchange in Turin, Italy, thinks the result is convincing evidence for Parkinson’s conjecture. But he would like to see further testing. “The outcome might well change significantly if you change the shape of the social network, or the way people’s opinions influence one another,” he says. So might this kind of work offer a rational way to optimise our decision-making bodies? One curious detail provides an intriguing slant on this question. In the computer simulations, there is a particular number of decision-makers that stands out from the trend as being truly, spectacularly bad, tending with alarmingly high probability to lead to deadlock: eight. Where this effect comes from is unclear. But once again, Parkinson had anticipated it, noting in 1955 that no nation had a cabinet of eight members. Intriguingly, the same is true today, and other committees charged with making momentous decisions tend to fall either side of the bedevilled number: the Bank of England’s monetary policy committee, for example, has nine; the US National Security Council has six. So perhaps we all subliminally know the kind of things that Parkinson highlighted and the computer simulations have confirmed. As Parkinson noted, we ignore them at our peril. Charles I was the only British monarch who favoured a council of state of eight members. His decision-making was so notoriously bad that he lost his head. ● Further Reading: Parkinson’s Law, or The Pursuit of Progress by C. Northcote Parkinson (Murray, 1958) 10 January 2009 | NewScientist | 39

Interview Photography: Bertrand Desprez

Close to the bones Too many diamonds, not enough fossils. That was Brigitte Senut’s verdict on a Namibian diamond mine she once visited. In 2000, she discovered Orrorin tugenensis, the first human ancestor known to have walked upright, in the Tugen Hills of Kenya. She told Laura Spinney about fossil-hunting in Africa What is the big question you’re trying to answer?

The find was controversial. Why?

How and when did humans diverge from the African great apes? I’m interested not only in the physical characteristics of those early ancestors, but also in how they lived, what environments they inhabited. That’s why I’m as excited by the discovery of a pig, a snail or a rodent as by a primate. It’s also why I work with geologists, sedimentologists and palaeobotanists, among others.

According to the dominant paradigm at the time, there were no hominids or human ancestors on Earth before the Pliocene, the geological epoch that began 5.5 million years ago. As soon as I laid eyes on Orrorin I knew our problems were only just beginning. Sure enough, some people said we had unearthed chimpanzee remains. Everyone now acknowledges that Orrorin is of the human family, but there is still a debate over the relationship between Orrorin and Lucy. Are they both direct ancestors of modern humans, or did the australopithecines branch off at some point?

Immediately. The head worker at the site, Kiptalam Cheboi, found two fragments of a jaw. Other members of the team then uncovered two femurs and a humerus. We went on to study the femurs in more detail, but we could already see from their morphology that they belonged to a bipedal hominid. And from the geology of the site, we knew that it was 6 million years old. That put back the origins of bipedalism by about 3 million years, since the oldest biped known up to that point was the Ethiopian australopithecine Lucy.

Profile Brigitte Senut has participated in the discovery of numerous extinct primates in Africa, including the oldest to date, at 18 million years. Since 1976 she has been based at the Natural History Museum in Paris. In 1985 she organised her first expedition to Uganda, to search for the origins of humans. She won France’s esteemed Prix Irène Joliot-Curie in October 2008 and was also named French female scientist of the year. That same month her latest book, Et le singe se mit debout (And the Ape Stood Up), was published by Albin Michel.

40 | NewScientist | 10 January 2009

Do you consider Orrorin to be the notorious “missing link”?

No! The missing-link concept implies that a great ape of the modern kind is the common ancestor, but the ancestor of Orrorin bore no resemblance to modern chimpanzees.

AGENCE VU

When did you know that the bones you unearthed in 2000 were important?

What does the name mean?

“The original being”, in the Tugen language of Kenya. The Tugen people have long devoted songs and dances to this mythical creature. What did Orrorin look like?

A young adult was between 1.10 and 1.37 metres tall, that is, slightly taller than Lucy. Like Lucy, it climbed trees as well as walking on two feet. But while Lucy had a small skeleton and large teeth, Orrorin had small teeth and a relatively large skeleton. It seems unlikely to me that a microdont such as Orrorin gave rise to a macrodont like Lucy, which in turn gave rise to the microdonts that were later hominids, but others disagree.

Do you know how the first individual whose remains you found died?

Some of the bones were covered in a fine layer of sodium carbonate, which made me think initially that it may have ventured onto the fragile crust of a hot soda lake – the likes of which you still find in the Rift Valley today – fallen through it and become trapped. However, one of the bones, a femur, also has tooth marks on it, and the top part is missing, as if the leg had been ripped away from the torso at its fleshiest part. That’s how a leopard tackles its prey. I think a leopard-like animal killed Orrorin, then carried its carcass up into a tree. From www.newscientist.com

For Brigitte Senut, retracing evolution using fossil DNA still isn’t as reliable as the fossil record itself

Kalashnikovs. My Swahili was pretty basic back then, but luckily my colleague spoke it, and so did their leader. The negotiations ended peacefully enough with them helping us to rescue the car and wishing us a good trip, but I was furious. The next morning, I woke to find a whitebearded old man standing in front of my tent, leaning on his stick, trembling. He was the warriors’ chief, and he had walked through the night to come and apologise to me. He gave me a pot of honey and held my hand for a long time. I forget if there was a translator, or what language we communicated in. But I will never forget his face or his dignity, his anger and his embarrassment. Working in a war zone didn’t faze you?

It wasn’t exactly a war, and if Uganda wasn’t easy to operate in, we managed. Having said that, there were times when I was frightened. In the late 1980s and 90s the roadblocks were often manned by child soldiers. They were armed, they were children – there was no reasoning with them. There was also the risk of ambush by the Lord’s Resistance Army, though we were fortunate enough to be spared that ordeal. Are there any difficulties in being a woman?

No, although I was almost sold in marriage once. That was in Karamoja, in north-east Uganda. The chief of a subdistrict there told a colleague of mine that I walked well and he wanted to marry me. He was offering a dowry of two camels, 50 cows, five ducks and five bundles of wood. Do you enjoy fieldwork?

time to time, its bones dropped into the lake below. That’s just one possible scenario, but it fits the facts. How well does the molecular biologist’s view of human evolution fit with the palaeontologist’s?

They are complementary. We both agree that the African great apes are our closest relatives, but the dates of the divergence put forward by the molecular biologists are a bit recent with respect to the story the fossils tell. The study of DNA is relatively new in this context, and it doesn’t yet take full account of the genetic variability between species and subspecies of ape. However, it’s a field that’s evolving fast. www.newscientist.com

“I was almost sold in marriage once in north-east Uganda”

I’m passionate about it, and I think it’s essential for a palaeontologist. On a human level, I have had wonderful experiences in the field. The peace and solitude of the Namibian desert are almost necessary to me now. When I’m there, I feel as if my brain has been washed clean. I have written through the night while camping in the dunes. When is your next trip?

You must have had some close shaves, having worked in the field for nearly 25 years.

Once, in Uganda, our car got stuck in a hole and we found ourselves being shot at. This was just before the coup d’état of June 1985. Suddenly we were surrounded by 20 young warriors who rifled our car and touched my hair and clothes. They were stark naked apart from the feathers in their hair, their cartridge belts and

As soon as the rains are over, in April or May, I’ll go to Uganda and Namibia. We have only explored a fraction of the area that potentially holds the secret of our existence. We know peanuts compared with what there is to know. So Africa is in your blood.

And in yours. Your ancestors were African, don’t forget. ● 10 January 2009 | NewScientist | 41

Review Freaks of Nature: Developmental anomalies and evolutionary diversity by Mark S. Blumberg, Oxford University Press, £12.99, ISBN 9780195322828 LUKE MACGREGOR/REUTERS

NATURE’S FABULOUS FREAK SHOW As animal embryos develop, plenty of things can go wrong, but in the face of even the strangest abnormalities, bodies make clever adjustments. The resulting freaks have a lot to teach us about evolution, finds John Whitfield

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THERE’S no getting around it: freaks are fascinating. We no longer pay to gawp at bearded ladies in sideshows, but turn on the TV and you will find such documentaries such as The woman with half a body, The boys joined at the head or The girl with eight limbs (all real titles). For many of us, it’s a morbid curiosity, but Mark Blumberg wants to harness this fascination to a noble end. Understanding how freakish developmental anomalies come about, he argues, can help us understand how normal bodies are made and how evolution has produced such a dazzling diversity of forms. Many biologists automatically ascribe freak qualities to mutated genes, but some are realising that embryonic development can play just as important a role. Conditions like cyclopia (one central eye) and dicephalus (two

“Strict definitions of normality have no real basis in science” heads on one body) do not require genetic mutations but can occur if, for instance, the mother drinks alcohol while pregnant. The key, says Blumberg, is that development is not a rigid programme. Instead, the embryo monitors its environment and adjusts accordingly. There’s a clear evolutionary advantage to this. Imagine navigating a road trip using a specific route you downloaded off the web. The 42 | NewScientist | 10 January 2009

list of instructions is fine – until you get lost or hit a traffic jam, at which point you’re stuck. A map, on the other hand, would allow you to find alternative paths to your destination. The journey from fertilised egg to trillion-celled adult is so complicated and chancy that none of us would make it if there were no room for last-minute manoeuvres. So development is like a map with the destination circled: responding to internal and external factors, the body finds its way one step at a time. It’s a testament to the system’s robustness that even when things go very wrong – if two embryos fuse into a conjoined twin, or if thalidomide distorts limb growth – the resulting beings can survive and even thrive. Bones and muscles can reshape so that, for example, a goat born without front legs can walk upright. Not only that, brain regions that would have served the missing parts are reassigned. There are also behavioural workarounds: Sanders Nellis, an “armless wonder” in P. T. Barnum’s 19th-century circus, could load and fire a pistol with his feet. Instead of pitying such folk, Blumberg argues, we should admire them, and accept that strict definitions of normality have no real basis in science. This is all good sense. What’s less clear in the book is what the abilities of individuals to adapt to anatomical quirks and environmental insults tells us about the evolutionary process

Not all novelties are due to DNA mutation; embryos can offer their own surprises

that adapts animals to their environments. Some biologists think that our insights into development’s flexibility and robustness should cause a major rethink of how evolution works. Instead of seeing adaptation as arising solely by natural selection acting on tiny variations thrown up by random genetic mutations, it might be that development can generate variability suited to the environment, and that in some cases genes follow this adaptation rather than lead. These views are controversial. Experiments in the lab show that evolution can work this way, but how often the same happens in the wild is unclear. Blumberg seems sympathetic to a

development-driven view of evolution, but his exact position is vague, and this is the book’s weakness. Without a central thesis or strong narrative thread, Freaks of Nature reads rather like Blumberg’s description of embryonic development: “There is no single narrator and no internal dialogue. There is what just happened, what is happening now, and what comes next.” This can make for a confusing read, but it is a reflection of real scientific uncertainty. Timely and wide-ranging, Freaks of Nature shows that although we’ve passed some exciting landmarks on our journey, we’re still some distance from that circled destination, and the route is still unclear. ● John Whitfield is the author of In the Beat of a Heart (Joseph Henry Press, 2006) www.newscientist.com

Quantum physicist Paul Dirac is an icon of modern thought, despite his refusal to engage with colleagues, students and even his own family. A gripping new biography gives a real insight into his life and times, says Pedro Ferreira The Strangest Man: The hidden life of Paul Dirac, quantum genius by Graham Farmelo, Faber, £22.50, ISBN 9780571222780

PAUL DIRAC’S terseness is legendary. The master of monosyllabic answers, he went through life refusing to engage with colleagues, students and even his own family. Having read many examples of Dirac’s repartee in Graham Farmelo’s new biography The Strangest Man, I have to confess that he comes across as a truly unpleasant man. I am surprised that people put up with him. Dirac was the theoretician’s theoretician, responsible for a crucial piece of the explanation of fundamental particles and forces. His equation, which he proposed in 1928, married the quantum physics of Schrödinger and Heisenberg with Einstein’s special relativity. With it, he predicted the existence of antiparticles, subsequently discovered in detailed studies of cosmic rays, and shared the Nobel prize for physics with Schrödinger in 1933. Surprisingly, the experimental verification of his prediction seemed of no great import to the Englishman. To him, the truth of a physical theory lay in its mathematical beauty, not in its experimental verifiability. Throughout his life, he applied this filter to almost everything he worked on. As a result, and after Lost in translation? What was behind Paul Dirac’s spiky demeanour? www.newscientist.com

an incredibly productive period in his twenties and thirties, he became detached and reluctant to accept the stunning developments of the generation of physicists that followed him. Farmelo has used a stash of Dirac’s letters and notes to build an enthralling yet deeply depressing narrative. Dirac came from a dysfunctional family: a mediocre, authoritarian father and a cloying, resentful mother who batted their successful son back and forth between them throughout their long marriage. Dirac took his mother’s side but resented the sporadic trips that he had to take to their small family home in Bristol. His older brother committed suicide in his early twenties and although Dirac, true to himself, refrained from any public show of grief, Farmelo reveals that he was profoundly scarred by this event

Dirac, to the point Was this brilliant physicist genuinely unpleasant or simply misunderstood? Judge for yourself from these anecdotes. Attending a meeting in a castle, a fellow guest warned Dirac that a certain room was haunted by a ghost that always appeared at midnight. “Is that midnight Greenwich time, or daylight-saving time?” Dirac asked. Classicist John Crook tried making small talk with Dirac in the Hall of St John’s College, Cambridge. Crook said, “Cold, isn’t it?” After long thought, Dirac replied, “How cold?” Dirac was often invited to summer garden parties at Buckingham Palace, but found them a chore. When a colleague was invited he asked Dirac how to make the most of the event. “Get a large piece of cake and sit by the lake” was the reply. Dirac often dozed during other people’s lectures, occasionally waking to make a sharp remark. An unfortunate speaker once paused in confusion: “Here is a minus where there should be a plus. I seem to have made an error of sign.” Dirac opened one eye and said: “Or an odd number of errors.”

Pedro G. Ferreira is professor of astrophysics at the University of Oxford BETTMAN/CORBIS

SPIKY QUANTUM GENIUS LAID BARE

throughout his life. All this is used to justify Dirac’s demeanour. The Strangest Man is a long, laboured, but engaging book. Farmelo cuts back and forth between Dirac’s ideas, his interactions with his colleagues and his painful relationship with his family. The ideas are not explained in great detail but the fraught and thrilling exchanges between the founders of quantum physics – as well as between the giants of the University of Cambridge in the 1920s and 30s – make for a gripping read. His involvement with his family shifts gears when he marries Manci Wigner, the outspoken, volatile sister of physicist Eugene Wigner. Their fractious but long marriage is dissected in detail and is the main thread of his story in the last 30 years of Dirac’s life. Towards the end of the book Farmelo hazards an alternative explanation for Dirac as a person and thinker: he may have been autistic. Farmelo’s suggestion is plausible and he makes a strong case, but it is also part of a modern trend of excusing antisocial geniuses for their odd behaviour. Regardless of whether Dirac was autistic or simply unpleasant, he is an icon of modern thought and Farmelo’s book gives us a genuine insight into his life and times. ●

When Dirac first visited Niels Bohr’s institute in Copenhagen, his utterances consisted almost entirely of three phrases: “Yes”, “No” and “I don’t mind”. Later, he became more flexible. When astrophysicist Subrahmanyan Chandrasekhar expounded his views, Dirac repeatedly interjected with “Yes”, Hebut explained later, “When I say Yes, it does not mean that I agree; it means only that you should go on.” In 1929, Dirac sailed from America to Japan with Werner Heisenberg. During the trip, Heisenberg spent the evenings dancing while Dirac looked on, puzzled. Eventually Dirac asked his friend why he danced. Heisenberg replied, “Well, when there are nice girls it is a pleasure to dance.” After thinking for 5 minutes, Dirac said: “But how do you know beforehand that the girls are nice?”

10 January 2009 | NewScientist | 43

Histories

TISSANDIER COLLECTION/LIBRARY OF CONGRESS

Like a lead balloon

METAL airships are one of the oldest notions in aeronautics. As early as 1670, Italian mathematician Francesco Lana published his Demonstration of the Feasibility of Constructing a Ship With Rudder and Sails, Which Will Sail Through the Air. Lana proposed evacuating the air from a set of copper spheres, which he reasoned would weigh less than the surrounding air and would ascend until the weight of the sphere reached equilibrium with the surrounding atmosphere. He calculated that four vacuum spheres, each with a diameter of 7.5 metres, could lift a boat carrying six passengers. Lana, alas, could not procure the copper spheres himself because of his obligations as a Jesuit. “I would have willingly [built it] before publishing these my inventions,” he explained, “had not my vows of poverty prevented my expending 100 ducats.” Lana’s notion was not entirely fanciful. Recent experiments had demonstrated that air had weight, and in 1650 the German inventor and scientist Otto von Guericke had drawn together small copper hemispheres with such a strong vacuum that teams of horses could not pull them apart. Still, there was a difference between creating a sturdy 50-centimetre sphere and fashioning 7.5-metre globes that could rise into the clouds. As Lana’s compatriot Giovanni Borelli pointed out, for Lana’s spheres to be light enough to fly, the copper would have to be so thin that on evacuation they would be crushed by atmospheric pressure. Nonetheless, Lana’s idea transfixed Europe for the next century. By 1672, translations and engravings depicting his balloon had 44 | NewScientist | 10 January 2009

In 1844, Parisians with an extra franc in their pocket could wander to the outskirts of the city and buy entry to a mysterious building on Impasse du Maine, a narrow dead-end street just behind the new railway station at Montparnasse. Inside a cavernous hangar, proprietor Edmond Marey-Monge and his team of workmen laboured away, soldering together long sheets of metal to make a giant sphere. Just what this contraption was for only became clear after examining the blueprints: valves for introducing hydrogen and attachments for a passenger gondola hinted at a new mode of transport. The gleaming sphere, Marey-Monge announced, was a “ballon de cuivre” – a brass balloon.

appeared in Germany, and in London Robert Hooke penned an English translation. A century later, Lana’s copper balloons were still celebrated in poems. They appear in a German interplanetary travelogue of 1744 envisaging trips to Mars, and in 1768 an epic poem in Latin predicted their use in airlifts to rescue those “shaken by repeated earthquakes”. But with the first successful flight of a hot-air balloon in Paris in 1783, Lana’s concept of a rigid vacuum airship fell by the wayside. Except, that is, in Paris itself. In 1844, inventor Edmond Marey-Monge suggested in the journal Comptes Rendus that for “aerial navigation to be able to render the same services as the navy”, balloons must be in

“He could hear the hiss of lost money as the gas escaped through leaks” “a position to resist, like our ships, the bad weather of ten or fifteen years of service”. Unlike fragile balloons made of fabric, metal airships could stay aloft indefinitely while performing their commercial or military duties. After three years working in a custombuilt hangar at number 10 Impasse du Maine, on what was then the southern edge of Paris, Marey-Monge was ready to fulfil Lana’s vision. Rather than extract the air from a set of spheres, he planned to fill a single giant sphere with hydrogen. His balloon would be 10 metres across and made from 0.1-millimetre-thick brass sheets banded and soldered together. “I prefer the spherical

form,” Marey-Monge explained, “because under the smallest surface it contains the greatest capacity”, and so, kilo for kilo of brass, gets the greatest lift from the gas it contains. And lift was just what Marey-Monge needed, because despite the thinness of the metal, his balloon weighed 400 kilograms. His choice of material had several other drawbacks: not only were the curved brass plates difficult to solder together, but French foundries were unable to create the long, thin panels he needed. Marey-Monge had to import brass sheets, each 5 metres long and 50 centimetres wide, from a Prussian foundry. Then he had to construct a temporary wooden frame for workers to build the sphere around. To cap it all, the sheets were so thin, they developed countless tiny holes, and to prevent leaks he was forced to line the interior with thin layers of tissue, glue and varnish, adding another 16 kilograms to its weight. While Parisians bought their tickets to watch the giant orb take shape, the project also captured imaginations abroad. The merits of metal balloons were debated at length by armchair aeronauts in Britain, including one who wrote to Mechanics Magazine to suggest an “iron balloon” 400 foot (120 metres) wide as “not contrary to the spirit of the times” – though, he allowed, it might “gambol about the Earth’s surface with great danger to life and limb of the human race, as well as terror to animal creation generally”. Marey-Monge planned to launch his balloon on 2 June 1844. Extracting the wooden supports from inside the globe proved a delicate operation, as the balloon’s skin was thin and easily damaged. But at last the vast www.newscientist.com

MARY EVANS PICTURE LIBRARY

Francesco Lana calculated that four evacuated spheres could lift a boat and six passengers

globe seemed ready to fly. And so, with a turn of the valve, Marey-Monge filled his contraption with the 523 cubic metres of hydrogen it would need to break free of the Earth. And then… nothing. It wasn’t budging. Marey-Monge thrust his head through the hole at the base of the balloon and into the dark chamber. The air at the bottom of the sphere was still perfectly breathable, so much so that he could stand there for a full 15 minutes contemplating the cruelties of gravity. Pumping in the precious remainder of his hydrogen supply did not help: when he www.newscientist.com

thrust his head inside again he could hear the hiss of lost money as the gas escaped through leaks in the brass skin. The balloon never did fly, and MareyMonge wound up selling the brass for scrap. It was little consolation for a project that had taken three years and cost him a fortune. Despite its ignominious end, the brass balloon had fired the Victorian imagination. Patents for metal airships appeared with some regularity, including a proposal in 1887 for a steel blimp 126 metres long. Yet even MareyMonge eventually concluded that metal

airships would remain unworkably fragile and leaky until a metal light enough to allow overlapping layers could be procured. By 1897 a candidate had presented itself. Amid Germany’s pioneering work in Zeppelin construction, designer David Schwarz conceived of a daring approach: why not an aluminium dirigible? After building two prototypes, with the help of the Prussian Airship Battalion he launched a 38-metre airship from Tempelhof Field in Berlin. Built in the familiar “blimp” shape, it contained bags of hydrogen within a skin of riveted aluminium plates 0.2 millimetres thick. Incredibly, it worked. On 3 November 1897, Schwarz’s airship lumbered aloft, and sailed 6 kilometres into the German countryside. But mechanical mishaps and its rigid design meant that instead of gently nudging to a stop, the metal colossus crumpled into a field like so much expensive foil. Despite this, rigidity is one of the great attractions of metal-clads. Because their skin is less prone to deformation at higher speeds, a sleek metal-clad should be able to fly much faster than a textile-covered blimp. Goodyear’s original airship designer, Ralph Upson, certainly thought so. In 1929, he formed the Metalclad Airship Corporation to build an aluminium-clad helium airship, the ZMC-2, for the US navy. Although notoriously difficult to handle, the “Tin Bubble”, as it was dubbed, could reach a speed of 100 kilometres an hour, and it put in 2200 flight hours before it was decommissioned in 1941. No more metal-clads have taken to the skies since: they were too expensive to build and too difficult to handle. But the dream never quite died. Upson’s engineer Vladimir Pavlecka continued to patent innovations in the hope of a relaunch right until his death in 1980. Other designs have included one patented in 1964 that promised “jetpropelled dirigible airships”. Such notions are still floated wistfully by airship designers at conferences. Curiously, one man who remained ultimately unconvinced was none other than Francesco Lana himself, who feared what his metal airship might be capable of. “Fortresses and cities could thus be destroyed,” he wrote, “as iron weights, fireballs and bombs could be hurled from a great height.” So while airships were conceivable, the priest decided in 1670 that the havoc they would wreak meant that humans would never leave the ground. God, he concluded, “would surely never allow such a machine to be successful.” Paul Collins ● 10 January 2009 | NewScientist | 45

Commentary

THEA BRINE

World lines Lawrence Krauss

Obama is taking science seriously GIVEN the importance of energy policy in President-Elect Obama’s plans to revitalise the US economy, some pundits are worried that his choice for energy secretary, Nobel laureate physicist Steve Chu, lacks direct political experience. They shouldn’t. As director of one of the major US national laboratories, Chu has ample experience navigating the political waters in Washington. More importantly, decisions on US energy policy over the next decade should follow on from scientific and technological considerations, not the other way around. Energy policy will involve a complex interplay between two

pressing needs: to stimulate the economy and to build an infrastructure that can promote energy independence and sustainability while moderating greenhouse gas emissions and helping us break our dependence on hydrocarbon fuels. Obama has proposed spending $150 billion over 10 years on developing clean energy sources, and perhaps 10 times as much on improving national infrastructure through the creation of high-tech green jobs. Spending money on these areas is crucial, but throwing money indiscriminately at them would be tragic. It is vital at this time to have someone at

the helm of the Department of Energy who is prepared to make tough decisions about which technologies the government should invest in and how best to partner with private enterprise. Chu is eminently qualified in these areas. As director of the Lawrence Berkeley National Laboratory (LBNL), he helped to transform it into one of the main US research facilities for renewable energy technologies. He is also one of the leaders of a pioneering public-private partnership between LBNL, the University of California, the University of Illinois and BP that will focus over $400 million on energy-related biosciences research. This is just the kind of entrepreneurial model the US needs as it attempts to exploit one of its greatest natural resources, its scientific talent, to meet the challenges of the 21st century. As energy secretary, Chu’s greatest challenge will be to help Congress to act in the face of pressures from energy lobbyists of all persuasions. Here, too, he is eminently qualified. I can say from personal experience that he is not only a brilliant physicist but a dynamic communicator. One of the big challenges in his interactions with Congress and within the administration will be to educate people sufficiently to make informed

“Decisions on energy policy should follow science, not the other way around”

decisions on these complex issues. Having known Chu for almost 20 years, I can attest that few physicists combine this expertise in their field with such savvy understanding of how to run an institution. Moreover, once Chu moved to LBNL, he threw his intellect into the task of developing new technologies to deal with our increasing energy needs and looming climate change. Within a year his lectures on these subjects reflected mastery not only of the science, but of the economic and political challenges involved too. The choice of energy secretary may not be Obama’s most visible appointment, but it may yet be one of his most important. By moving outside the political arena to select one of the most capable scientists in the country to help guide US energy strategy, Obama has reinforced a principle that was too often missing during the election campaign: to solve the challenges we face, sound public policy must be based on sound science. Chu will be aided by a science “dream team”, including John Holdren as science adviser and Harold Varmus and Eric Lander as co-chairs of the President’s Council of Advisors on Science and Technology (see page 10). It is hard to imagine a more experienced and capable group of science leaders. It is time to leave behind a decade in which politics has largely trumped science. Obama’s appointments bode well for the future of this administration, and for our future too. ●

Enigma Square from primes No. 1527 Richard England HARRY, Tom and I were looking to find 5-digit perfect squares that consisted of a 2-digit prime followed by a 3-digit prime, neither prime starting with a zero. 46 | NewScientist | 10 January 2009

We each found a different example. My 2-digit prime was the same as Harry’s and my 3-digit prime was the same as Tom’s. Which square was found by (a) Harry, (b) Tom? £15 will be awarded to the sender of the first correct answer opened on Wednesday

11 February. The Editor’s decision is final. Please send entries to Enigma 1527, New Scientist, Lacon House, 84 Theobald’s Road, London WC1X 8NS, or to enigma@ newscientist.com (please include your postal address). The winner of Enigma 1521 is Louis Kennedy of Oslo, Norway.

Answer to 1521 Boat scenes The speed of the pleasure boats travelling along the canal between Eastbridge and Westford is 8 kilometres per hour Visit www.newscientist.com/topic/ enigma for recent puzzles and worked solutions www.newscientist.com

PAUL MCDEVITT

Feedback–

IT’S never to late to publicise threats to online security, so be warned that around this time last year Rusty Nash received an email appearing to come from the online payment service PayPal asking for account details. These were needed, it said, to implement a new security feature to protect the account from being savagely phished. It must have been really important, Rusty thought, as the subject line contained not one, but two exclamation marks!! And this was confirmed on opening the urgent message, which read: “PayPal and eBay have over 100000000 people worldwide dedicated to keeping PayPal accounts safe.” By his calculation, this means that 1 in every 66 people in the world must be working for PayPal and eBay on security alone. That would be pretty much the same proportion as when the old East Germany in its paranoid heyday hired a quarter of a million of its citizens to watch the 17 million others, and each other. Unless, of course, this was another example of meta-phishing: “I know,” thought some bright criminal spark, “Let’s scare people about all the nasties who are trying to phish their account details, and reassure them that if they’ll just give us their account details we can make them safe.”

Sam Warburton appreciated the appropriateness of this notice about a meeting of the Cardiff branch of the Philosophy Society: “The representational and relational character of perceptual experience (room yet to be confirmed)” 72 | NewScientist | 10 January 2009

STILL on the subject of the innumerable ways that computers make life, er, different: Mike Doyle writes to say that he goes beyond our password-picking method (6 December) by taking words of non-English origin and spelling them phonetically in English. You can even match the requirement imposed by HSBC bank, that your password be hard for you to remember, he reports: “I once used an alternative spelling of ‘pizza’ as a password. Months later, I spent a desperate half hour typing in alternatives, of which there proved to be a surprising number.” This brought up a point so painful that Feedback’s brain had hitherto consigned it to the suppressed memory bin. Never, ever enter accented characters when changing your Windows password. Some versions – NT4 at least – will happily accept élan!fatigué as your new password, but then refuse to accept that it could possibly be your password when you try to get back in.

POKING around the less frequently used facilities of the iTunes program, Miles Jay Wells finds it telling him that the file system on his iPod was created on Saturday 25 November 2028 at 17.37. Now, if someone would sell us an iPod preloaded with podcasts of horse races… Anyway, at the time Miles wrote to us, iTunes also reported that it had last been accessed on Thursday 1 January 1970. How could this be possible? Yes, we know that date is the beginning of the Unix epoch, but the iTunes access time was at 01.07, not 00:00. UPON checking how much of his 5-gigabyte download limit he had used up, Tim West was helpfully informed that he had used “21.940100000000001045918907038867 473602294921875 of 5120.0 Mb”. Internet service provider AT&T then added an important caveat: “This usage information summary is only an estimate.” Tim wants to know how much more precise the real figure can be. Counting 45 decimal digits there, and knocking off six digits, because the figure is in millions of bytes, Feedback’s mind is boggled wondering exactly what was conveyed by the transmission to Tim of those last 5 fractions of bits – or chicobytes, the proposed but unofficial name for 10-39 bytes, as we reported four years ago (4 December 2004).

VOLCANOES interest Craig Borland. It is not surprising, then, that he was visiting www.volcanoes.com – though it is perhaps surprising that there he found the announcement “Active Volcanoes – Thinking of buying? Compare 100s of retailers’ prices at Shopping.com”. He was disappointed not to find any listed on sale there at the moment – not even any dormant volcanos. Shame: “I had my heart set on a second-hand Kasatochi,” he laments. Keep looking is all we can say. You never know when new purchasing opportunities may erupt. A WELL-KNOWN online retailer had a recommendation for Sue Mac. “Dear Amazon.com Customer,” she was told, “We’ve noticed that customers who have purchased or rated So Wrong for So Long: How the Press, the Pundits – and the President – Failed on Iraq by Greg Mitchell have also purchased Town & Country Dogs by The Editors of Town & Country. For this reason, you might like to know that Town & Country Dogs will be released...” “I know that the minds of computers move in very mysterious ways,” says Sue,

“but I simply cannot fathom what caused the relevant software at Amazon to link the conflict in Iraq with a bunch of pampered pooches – except, perhaps, that it’s a dog of a war. Please, can anyone enlighten me?”

You can send stories to Feedback by email at [email protected]. Please include your home address. This week’s and past Feedbacks can be seen on our website. www.newscientist.com

The last word– EYE LEVEL The eye views images upside down in the manner of a camera lens, but our brains reinterpret this input to allow us to see things the correct way up. Have there been any examples of damage to this part of the brain causing people to see the world upside down? How does this happen, is the brain able to compensate and, if so, how?

● There is no example of damage to the brain causing people to see the world upside down. This is because the image itself doesn’t actually transfer directly to your brain; only a series of electrical signals is carried there. The lens of the eye does focus an upside down image onto the retina. This image is then translated into a series of electrical signals which travel down the optic nerve and pass through the lateral geniculate nucleus – a kind of way station – into the occipital (visual) cortex at the back of the brain. The reason that the upside down image does not get flipped is because there is no image to flip. In your brain there are only electrical signals being sent from neuron to neuron, transforming as they go. Your brain processes these signals to create your experience of sight. Experiments show that if imagery received by the eyes is inverted for a long time, these signals are simply reinterpreted by the brain and eventually perceived as the right way up. Gregory Szucs North York, Ontario, Canada Questions and answers should be concise. We reserve the right to edit items for clarity and style. Include a daytime telephone number and email address if you have one. Restrict questions to scientific enquiries about everyday phenomena. The writers of published answers will receive a cheque for £25 (or US$ equivalent). Reed Business Information Ltd reserves all rights to reuse question and answer material submitted by readers in any medium or format.

● The brain does not need any special mechanism to compensate for the image in the eye being upside down. Once the retina has converted the image into neural information, the physical arrangement of the information is arbitrary. For example, why should it matter to the brain cells dealing with the top half of the visual world that the nerves supplying them with information happen to originate in the bottom half of the retina? Tim McCulloch Camperdown, New South Wales, Australia ● As a child, I remember constructing a pinhole lens using toilet-paper rolls and tissue paper as the screens. I placed it against one eye and covered my other eye. These lenses invert the image of the world, and initially it was

“I wore lenses to invert the image of the world and after some time my brain adapted. Taking the lenses off caused everything to flip upside down again”

world would be similar to coping with a mirror-image view: at first, trying to correctly position something while looking in a mirror is very difficult, but with practice it becomes instinctual. Simon Iveson Warabrook, New South Wales, Australia ● It is generally known that our eyes form an inverted image of what we see and that the brain corrects the scene to look the right way up. However, when people wear inverting spectacles so that a scene is inverted before it enters our eyes, the wearer should see the world inverted. George Malcolm Stratton did this experiment in 1897 and claimed that the world looked the right way up again within a week. In other words, the brain “reinstated” upright vision. The experiment has been repeated a few times since, with mixed results, so the jury is still out on this claim. Experiments in the 1940s and 1950s showed that human subjects managed to ride bikes and to go skiing while wearing inverting spectacles, suggesting that they were seeing the world the right way up.

However, in the late 1990s a team led by David Linden refuted this claim in Perception (vol 19, p 469). Their paper suggests that those wearing inverting spectacles simply adapt to seeing the world upside down by learning new motor patterns and increasing their skill at spatial transformations. Mike Follows Willenhall, West Midlands, UK

THIS WEEK’S QUESTION Fly trap? When my family returned from a two-week holiday during the summer, we found a cluster of dead flies stuck to our porch window. Each was surrounded by a hazy mist on the glass. We have lived in our house for 20 years and have never seen this before. Even after two weeks, when the photograph below was taken, nothing had changed. The flies hadn’t moved and no predator had come to eat them. Can anyone explain what has happened? Stephen Ryder UK

very disorienting seeing everything upside down: I walked into doors and collided with any number of household objects. However, tactile feedback is a good teacher, and I learned to cope with it. After some time, my brain adapted and the image I was perceiving reverted back to normal. Then, of course, once I had adapted, taking the lens off caused everything to flip upside down again, until I readjusted once more. I guess that the ability of the brain to cope with an inverted view of the New Scientist retains total editorial control over the content of The Last Word. Send questions and answers to The Last Word, New Scientist, Lacon House, 84 Theobald’s Road, London WC1X 8NS, UK, by email to [email protected] or visit www.last-word.com (please include a postal address in order to receive payment for answers). For a list of all unanswered questions send an SAE to LWQlist at the above address.

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