Liver cancer survival time tripled by virus

The virus used in the vaccine that helped eradicate smallpox is now working its magic on liver cancer. A genetically engineered version of the vaccinia virus has trebled the average survival time of people with a severe form of liver cancer, with only mild, flu-like side effects.

Thirty people with hepatocellular carcinoma received three doses of the modified virus – code-named JX-594 – directly into their liver tumour over one month. Half the volunteers received a low dose of the virus, the other half a high dose. Members of the low and high-dose groups subsequently survived for, on average, 6.7 and 14.1 months respectively. By contrast, trials several years ago showed that sorafenib, the best existing medication for this cancer, prolonged life by only three months.

Two of the patients on the highest viral dose were still alive more than two years after the treatment. "It's a very substantial survival benefit," says Laurent Fischer, president of Jennerex, the company in San Francisco developing the treatment under the trade name Pexa-Vec.

Besides shrinking the primary tumour, the virus was able to spread to and shrink any secondary tumours outside the liver. "Some tumours disappeared completely, and most showed partial destruction on MRI scans," says David Kirn, head of the study at Jennerex. Moreover, the destruction was equally dramatic in the primary and secondary tumours.

"This clinical trial is an exciting step forward to help find a new way of treating cancers," says Alan Melcher of the University of Leeds, UK, who was not involved in the study. "It helps demonstrate the cancer-fighting potential of viruses, which have relatively few side effects compared with traditional chemo or radiotherapy," he says. "If it proves effective in larger trials, it could be available to patients within five years."

The fact that the virus appears able to spread to secondary tumours suggests that simply injecting the virus into the bloodstream may be effective. A trial to compare this treatment with injecting the virus directly into a tumour is under way.

Targeted at cancer

The virus has had a gene coding for an enzyme called thymidine kinase snipped out. The enzyme enables the virus to recognise and infect dividing cells. By removing the gene, the virus's developers have reduced the likelihood of healthy dividing cells being infected.

Instead, the virus exclusively attacks cancerous tissue, by targeting two genes that have increased activity in tumour cells. One genes is associated with an epidermal growth factor receptor, which stimulates the cancer to grow. The other is associated with a vascular endothelial growth factor, which enables the cancer to recruit its own blood supply. The virus reduces the activity of both genes, causing the infected cancer cell to wither and die.

What's more, the virus carries extra genes to prod the body's own immune system into action against the cancer. One produces granulocyte colony stimulating factor, a protein that encourages production of extra white blood cells at sites of infection. The other produces a protein not naturally found in humans, called Lac-Z, that earmarks infected cells for destruction.

Fischer says that to date, more than 200 people have received the virus, which has also shown promise against other types of cancer, including those of the kidney and skin. But he warns that not everyone sees a benefit. "We know why patients respond, but not why they don't," he says.

Journal reference: Nature Medicine, DOI: 10.1038/nm.3089

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Sooty ships may be geoengineering by accident

GEOENGINEERING is being tested - albeit inadvertently - in the north Pacific. Soot from oil-burning ships is dumping about 1000 tonnes of soluble iron per year across 6 million square kilometres of ocean, new research has revealed.

Fertilising the world's oceans with iron has been controversially proposed as a way of sucking carbon dioxide out of the atmosphere to curb global warming. Some geoengineers claim releasing iron into the sea will stimulate plankton blooms, which absorb carbon, but ocean processes are complex and difficult to monitor in tests.

"Experiments suggest you change the population of algae, causing a shift from fish-dominated to jellyfish-dominated ecosystems," says Alex Baker of the University of East Anglia, UK. Such concerns led the UN Convention on Biological Diversity (CBD) to impose a moratorium on geoengineering experiments in 2010.

The annual ship deposition is much larger, if less concentrated, than the iron released in field tests carried out before the moratorium was in place. Yet because ship emissions are not intended to alter ocean chemistry, they do not violate the moratorium, says Jim Thomas of the ETC Group, a think tank that consults for the CBD. "If you intentionally drove oil-burning ships back and forth as a geoengineering experiment, that would contravene it."

The new study, by Akinori Ito of the Japan Agency for Marine-Earth Science and Technology, is the first to quantify how shipping deposits iron in parts of the ocean normally deficient in it. Earlier models had assumed that only 1 to 2 per cent of the iron contained in aerosols, including shipping emissions, is soluble in seawater, so the remaining 98 to 99 percent would sink to the bottom without affecting ocean life. But Ito found that up to 80 per cent of the iron in shipping soot is soluble (Global Biogeochemical Cycles, doi.org/kdj). As this soot rapidly falls to the sea surface, it is likely to be fertilising the oceans.

In the high-latitude north Pacific - a region that is naturally iron-poor and therefore likely to be most affected by human deposits - ship emissions now account for 70 per cent of soluble iron from human activity, with the burning of biomass and coal accounting for the rest. Shipping's share will rise as traffic continues to grow and regulations restrict coal and biomass emissions.

Can we learn anything from this unintentional experiment? Baker thinks not. "The process isn't scientifically useful," he says, because the uncontrolled nature of the iron makes it difficult to draw meaningful comparisons.

The depositions are unlikely to be harmful at current levels, he says, but "given the uncertainties, I just don't know how much these iron emissions would have to increase before there was demonstrable harm to an ecosystem, or benefit in terms of carbon uptake, for that matter".

This article appeared in print under the headline "Ships inadvertently fertilise the oceans"

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Data-wiping algorithm cleans your cellphone

Paul Marks, chief technology correspondent

Mailing your cellphone to a recycling company might make you a few pounds, but it can leave you at risk of identity theft. The deletion techniques recycling companies use are meant for hard discs, and so don't work on the solid-state flash memory used in mobile phones. That means personal data like banking info, texts, contacts and pictures can end up in the hands of, well, anyone the phone ends up with.  

To remedy the problem, British company BlackBelt Smartphone Defence of Skelmersdale, Lancashire claims to have developed a software algorithm that can securely delete data on cellphone memory chips. The trouble with data in a flash memory chip is that it is protected by an on-chip protection algorithm called the wear leveller. This hard-coded routine does its best to ensure the chip's lifetime is maximised so that each memory cell's ability to store charge is not worn out.

"The problem is that the wear-levelling algorithm ends up working
against the data wiping technique used for hard drives, which tries to
overwrite all the data,"
says the company's Ken Garner.

What the firm has done is write their own algorithm, called BlackBelt DataWipe, that works with,
rather than against, the leveller routine to render data
irrecoverable. "It is like having a shredder for personally identifiable
data," says Garner.

However, they don't yet know if their method is proof against sophisticated, nation-state level attacks - which might use electron microscopes
to read the last vestiges of the zeros and ones on a memory chip. "I imagine
if you're GCHQ you'll probably have technology that could get around
this and recover it in some way," says Garner.

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Robot inquisition keeps witnesses on the right track

MEMORY is a strange thing. Just using the verb "smash" in a question about a car crash instead of "bump" or "hit" causes witnesses to remember higher speeds and more serious damage. Known as the misinformation effect, it is a serious problem for police trying to gather accurate accounts of a potential crime. There's a way around it, however: get a robot to ask the questions.

Cindy Bethel at Mississippi State University in Starkville and her team showed 100 "witnesses" a slide show in which a man steals money and a calculator from a drawer, under the pretext of fixing a chair. The witnesses were then split into four groups and asked about what they had seen, either by a person or by a small NAO robot, controlled in a Wizard of Oz set-up by an unseen human.

Two groups - one with a human and one a robot interviewer - were asked identical questions that introduced false information about the crime, mentioning objects that were not in the scene, then asking about them later. When posed by humans, the questions caused the witnesses' recall accuracy to drop by 40 per cent - compared with those that did not receive misinformation - as they remembered objects that were never there. But misinformation presented by the NAO robot didn't have an effect.

"It was a very big surprise," says Bethel. "They just were not affected by what the robot was saying. The scripts were identical. We even told the human interviewers to be as robotic as possible." The results will be presented at the Human-Robot Interaction conference in Tokyo next month.

Bilge Mutlu, director of the Human-Computer Interaction Laboratory at the University of Wisconsin-Madison, suggests that robots may avoid triggering the misinformation effect simply because we are not familiar with them and so do not pick up on behavioural cues, which we do with people. "We have good, strong mental models of humans, but we don't have good models of robots," he says.

The misinformation effect doesn't only effect adults; children are particularly susceptible, explains the psychologist on the project, Deborah Eakin. Bethel's ultimate goal is to use robots to help gather testimony from children, who tend to pick up on cues contained in questions. "It's a huge problem," Bethel says.

At the Starkville Police Department, a 10-minute drive from the university, officers want to use such a robotic interviewer to gather more reliable evidence from witnesses. The police work hard to avoid triggering the misinformation effect, says officer Mark Ballard, but even an investigator with the best intentions can let biases slip into the questions they ask a witness.

Children must usually be taken to a certified forensic child psychologist to be interviewed, something which can be difficult if the interviewer works in another jurisdiction. "You might eliminate that if you've got a robot that's certified for forensics investigations, and it's tough to argue that the robot brings any memories or theories with it from its background," says Ballard.

The study is "very interesting, very intriguing", says Selma Sabanovic, a roboticist at Indiana University. She is interested to see what happens as Bethel repeats the experiment with different robot shapes and sizes. She also poses a slightly darker question: "How would you design a robot to elicit the kind of information you want?"

This article appeared in print under the headline "The robot inquisition"

It's all about how you say it

When providing new information, rather than helping people recall events (see main story), a robot's rhetoric and body language can make a big difference to how well it gets its message across.

Bilge Mutlu of the University of Wisconsin-Madison had two robots compete to guide humans through a virtual city. He found that the robot which used rhetorical language drew more people to follow it. For example, the robot saying "this zoo will teach you about different parts of the world" did less well than one saying "visiting this zoo feels like travelling the world, without buying a plane ticket". The work will be presented at the Human-Robot Interaction conference in Tokyo next month.

If you would like to reuse any content from New Scientist, either in print or online, please contact the syndication department first for permission. New Scientist does not own rights to photos, but there are a variety of licensing options available for use of articles and graphics we own the copyright to.

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Today on New Scientist: 6 February 2013

Open Richard III DNA evidence for peer review

A good case has been made that a skeleton unearthed from a car park is that of the last Plantagenet king of England - it's time to share the data

Universal bug sensor takes guesswork out of diagnosis

A machine that can identify all bacteria, viruses and fungi known to cause disease in humans should speed up diagnosis and help to reduce antibiotic resistance

Choking China: The struggle to clear Beijing's air

As pollution levels return to normal in China's capital after a record-breaking month of smog, what can be done to banish the smog?

Genes mix across borders more easily than folk tales

Analysing variations in folk tales using genetic techniques shows that people swap genes more readily than stories, giving clues to how cultures evolve

Sleep and dreaming: Slumber at the flick of a switch

Wouldn't it be wonderful to pack a good night's sleep into fewer hours? Technology has the answer - and it could treat depression and even extend our lives too

Closest Earth-like planet may be 13 light years away

A habitable exoplanet should be near enough for future telescopes to probe its atmosphere for signs of life

Lifelogging captures a real picture of your health

How can lifelogging - wearing a camera round your neck to record your every move - reveal what's healthy and unhealthy in the way we live?

Musical brains smash audio algorithm limits

The mystery of how our brains perceive sound has deepened, now that musicians have broken a limit on sound perception imposed by the Fourier transform

Magnitude 8 earthquake strikes Solomon Islands

A major earthquake has caused a small tsunami in the Pacific Ocean, killing at least five people

Nuclear knock-backs on UK's new reactors and old waste

Plans to build new reactors in the UK are stalling as yet another company pulls out, and there is still nowhere to store nuclear waste permanently

Amateur astronomer helps Hubble snap galactic monster

An amateur astronomer combined his pictures with images from the Hubble archive to reveal the true nature of galactic oddball M106

Nightmare images show how lack of sleep kills

Fatigue has been blamed for some of worst human-made disasters of recent decades. Find out more in our image gallery

Read More..

Today on New Scientist: 5 February 2013

Engineering light: Pull an image from nowhere

A new generation of lenses could bring us better lighting, anti-forgery technology and novel movie projectors

Baby boomers' health worse than their parents

Americans who were born in the wake of the second world war have poorer health than the previous generation at the same age

New 17-million-digit monster is largest known prime

A distributed computing project called GIMPS has found a record-breaking prime number, the first for four years

Cellular signals used to make national rainfall map

The slight weakening of microwave signals caused by reflections off raindrops can be exploited to keep tabs on precipitation

NASA spy telescopes won't be looking at Earth

A Mars orbiter and an exoplanet photographer are among proposals being presented today for how to use two second-hand spy satellites that NASA's been given

China gets the blame for media hacking spree

The big US newspapers and Twitter all revealed last week that they were hacked - and many were quick to blame China. But where's the proof?

Nobel-winning US energy secretary steps down

Steven Chu laid the groundwork for government-backed renewable energy projects - his successor must make a better case for them

Sleep and dreaming: Where do our minds go at night?

We are beginning to understand how our brains shape our dreams, and why they contain such an eerie mixture of the familiar and the bizarre

Beating heart of a quantum time machine exposed

This super-accurate timekeeper is an optical atomic clock and its tick is governed by a single ion of the element strontium

A life spent fighting fair about the roots of violence

Despite the fierce conflicts experienced living among anthropologists, science steals the show in Napoleon Chagnon's autobiography Noble Savages

Challenge unscientific thinking, whatever its source

Science may lean to the left, but that's no reason to give progressives who reject it a "free pass"

Need an organ? Just print some stem cells in 3D

Printing blobs of human embryonic stem cells could allow us to grow organs without scaffolds

Ice-age art hints at birth of modern mind

An exhibition of ice-age art at London's British Museum shows astonishing and enigmatic creativity

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Ice-age art hints at birth of modern mind

Sumit Paul-Choudhury, editor

Figurines from the Don river valley (Images: Kirstin Jennings)

The world’s oldest portrait, the world’s first fully carved sculpture, the world's oldest ceramic figure, the world’s earliest puppet - there’s no shortage of superlatives in the new exhibition of art from the ice age at the British Museum in London

But focus too closely on the exhibits’ record-breaking ages alone, and you might miss the broader point: these beautiful objects are the earliest evidence we have of humans who seem to have had minds like ours.

Consider, for example, the "lion man" found in 1939 in south-west Germany’s Stadel cave (pictured above). As the name suggests, this statue, standing 30 centimetres tall, harmoniously combines human and leonine features: the head is unmistakeably a lion’s, while the body and lower limbs are more human.

This is clearly the product of artistic creativity rather than a naturalistic drawing from life - suggesting that whoever carved it some 40,000 years ago had the capacity to express their imagination, as well as to replicate what they saw around them.

The temptation to speculate about what symbolic meaning the lion man might have had is, of course, irresistible. It was clearly valuable, taking around 400 hours and enormous skill to carve from a single piece of mammoth ivory.

The exhibition also includes a second, much smaller, feline figure found in another cave nearby, pointing to the idea that such imaginative objects might have cultural significance, perhaps as ritual objects within a shamanic belief system, rather than being isolated art objects.

Given what we know of modern traditions, that would make sense - but there is no hard evidence that anything resembling those traditions existed in Europe during the ice age.

Almost every object on show invites similarly thought-provoking consideration. Thumb-sized figurines from settlements along Russia's Don river (top) seem to present a woman's perception of her own pregnant body in an age before mirrors: no face, bowed head, the shelf of the bosom, the protrusion of the hips and buttock muscles and the swell of the belly. Were they carved by the women themselves, perhaps as protective talismans for themselves or their unborn children? And if so, what are we to make of those that were apparently deliberately destroyed subsequently?

Only a few of the animal models found at the Czech site of Dolní Věstonice are intact. The rest had shattered into thousands of clay fragments when they were heated while still wet. This must also have been deliberate: was the dramatic shattering part of a rite?

A tiny relief of a human figure with upraised arms invites interpretation as a celebrant or worshipper. Was he or she participating in a ceremony to promote social cohesion during tough times - perhaps to the accompaniment of music played on instruments such as the flute displayed nearby, which is precisely carved from a vulture's wing-bone?

Such interpretations deserve a healthy dose of caution, of course. The note accompanying an elegantly carved water bird (perhaps a cormorant) found near the smaller lion man drily reads: "This sculpture may be a spiritual symbol connecting the upper, middle and lower worlds of the cosmos reached by a bird that flies in the sky, moves on land and dives through water. Alternatively, it may be an image of a small meal and a bag of feathers."

In the total absence of documentary evidence, there is no way of telling which is correct: archaeological material might help clarify the utilitarian perspective, but it is far less helpful when it comes to discovering any symbolic value.

In any case, there is very little archaeological evidence on display at the British Museum. Curator Jill Cook says she was keen to avoid exhausting visitors with copious background material about the evolutionary and environmental contexts in which these objects were made.

Humans were capable of complex behaviour long before they reached Europe - as demonstrated by discoveries such as the 100,000-year old "artist's workshop" in South Africa's Blombos cave - but Cook thinks the explosion of art among Europeans 40,000 years ago may reflect changing social needs during the ice age.

When Homo sapiens first arrived in Europe some 45,000 years ago, "the living was initially probably reasonably easy", explains Cook. They would have found temperatures only about 5 °C lower than they are now, she says, and grassy prairies would have been well stocked with bison. As the human population grew, they would have had to find new ways of building, socialising and organising themselves.

“And as it turns desperately cold, around 40,000 years ago, suddenly we have all this art," she says.

That may have reflected the need to communicate and develop ideas - a need pressing enough for people to spend hundreds of hours creating objects that generally seem to have had little quotidian function.

"This is all about planning and preconceiving and organising and collaborating and compromising," suggests Cook, "and that is something art and music helps us do."

The dazzling array of objects on display, spanning tens of thousands of years, anticipate practically every modern artistic tradition. The first portrait, dating back 26,000 years, includes closely modelled details of its female subject's unusual physiognomy, perhaps the result of an injury or illness.

But nearby is an extraordinary figure of similar age whose facial features are utterly abstract, resembling a visor with a double slit in it.

Another (above) has a body whose angular patterns anticipate Cubism by some 23,000 years: Picasso kept two copies of it in his studio. Elsewhere, there are doll-like models of women with stylised faces, and female forms streamlined into little more than slender, strategically curved lines.

Representations of animals, too, come in all forms, from incredibly realistic illustrations scratched onto stone or ivory, to elegantly minimal sculptures; there are even carvings designed to create the illusion of movement when viewed from different angles or rotated (above) - a form of prehistoric animation.

The masterpieces in the latter part of the show include - and sometimes combine - both precisely observed, superbly rendered naturalism, and more abstract work that is still beautiful, but much harder to interpret.

Carved mammoth tusks

"The brain likes to tease us," says Cook. "We don't just represent things with great realism and naturalism, we like to break things down into patterns. That sparks your imagination, and makes you curious and questioning.

“What’s so spectacular about the modern brain, and the mind that it powers, is that it doesn't just make everything simple, it pushes us to new ideas and new thoughts."

After tens of thousands of years, the objects displayed in this extraordinary exhibition still have the power to do just that.

Ice Age Art: Arrival of the modern mind runs at the British Museum from 7 February 2013

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Bug protects itself by turning its environment to gold

Mythical King Midas was ultimately doomed because everything he touched turned to gold. Now, the reverse has been found in bacteria that owe their survival to a natural Midas touch.

Delftia acidovorans lives in sticky biofilms that form on top of gold deposits, but exposure to dissolved gold ions can kill it. That's because although metallic gold is unreactive, the ions are toxic.

To protect itself, the bacterium has evolved a chemical that detoxifies gold ions by turning them into harmless gold nanoparticles. These accumulate safely outside the bacterial cells.

"This could have potential for gold extraction," says Nathan Magarvey of McMaster University in Hamilton, Ontario, who led the team that uncovered the bugs' protective trick. "You could use the bug, or the molecules they secrete."

He says the discovery could be used to dissolve gold out of water carrying it, or to design sensors that would identify gold-rich streams and rivers.

The protective chemical is a protein dubbed delftibactin A. The bugs secrete it into the surroundings when they sense gold ions, and it chemically changes the ions into particles of gold 25 to 50 nanometres across. The particles accumulate wherever the bugs grow, creating patches of gold.

Deep purple gold

But don't go scanning streams for golden shimmers: the nanoparticle patches do not reflect light in the same way as bigger chunks of the metal – giving them a deep purple colour.

When Magarvey deliberately snipped out the gene that makes delftibactin A, the bacteria died or struggled to survive exposure to gold chloride. Adding the protein to the petri dish rescued them.

The bacterium Magarvey investigated is one of two species that thrive on gold, both identified a decade or so ago by Frank Reith of the University of Adelaide in Australia. In 2009 Reith discovered that the other species, Cupriavidus metallidurans, survives using the slightly riskier strategy of changing gold ions into gold inside its cells.

"If delftibactin is selective for gold, it might be useful for gold recovery or as a biosensor," says Reith. "But how much dissolved gold is out there is difficult to say."

Journal reference: Nature Chemical Biology, DOI: 10.1038/NCHEMBIO.1179

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Two worms, same brains – but one eats the other

IF TWO animals have identical brain cells, how different can they really be? Extremely. Two worm species have exactly the same set of neurons, but extensive rewiring allows them to lead completely different lives.

Ralf Sommer of the Max Planck Institute for Developmental Biology in Tübingen, Germany, and colleagues compared Caenorhabditis elegans, which eats bacteria, with Pristionchus pacificus, which hunts other worms. Both have a cluster of 20 neurons to control their foregut.

Sommer found that the clusters were identical. "These species are separated by 200 to 300 million years, but have the same cells," he says. P. pacificus, however, has denser connections than C. elegans, with neural signals passing through many more cells before reaching the muscles (Cell, doi.org/kbh). This suggests that P. pacificus is performing more complex motor functions, says Detlev Arendt of the European Molecular Biology Laboratory in Heidelberg, Germany.

Arendt thinks predators were the first animals to evolve complex brains, to find and catch moving prey. He suggests their brains had flexible wiring, enabling them to swap from plant-eating to hunting.

This article appeared in print under the headline "Identical brains, but one eats the other"

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Astrophile: A scorched world with snow black and smoky

Astrophile is our weekly column on curious cosmic objects, from the solar system to the far reaches of the multiverse

Object: Titanium oxide snow
Location: The hot-Jupiter planet HD 209458b

There is something magical about waking up to discover it has snowed during the night. But there's no powdery white blanket when it snows on exoplanet HD 209458b. Snow there is black, smoky and hot as hell – resembling a forest fire more than a winter wonderland. Put it this way: you won't be needing mittens.

HD 209458b belongs to a family called hot Jupiters, gas-giant planets that are constantly being roasted due to their closeness to their sun. By contrast, the gas giants in our immediate neighbourhood, including Jupiter, are frigid, lying at the solar system's far reaches.

HD 209458b is also noteworthy because it is tidally locked, so one side is permanently facing towards its star while the other is in perpetual night. On the face of it, these conditions wouldn't seem to invite snow: temperatures on the day side come close to 2000° C, while the night side is comparatively chilly at around 500° C.

Snow made of water is, of course, impossible on this scorched world, but the drastic temperature differential sets up atmospheric currents that swirl material from the day side to night and vice versa. That means that any substances with the right combination of properties might be gaseous on the day side and then condense into a solid on the night side, and fall as precipitation. Say hello to titanium oxide snow.

Stuck on the surface

Although oxides of titanium make up only a small component of a hot Jupiter's atmosphere, these compounds have the right properties to fall as snow. But there was a snag that could have put a stop to any blizzards. Older computer models of hot Jupiters suggested that titanium oxides condensing in the air on the night side would snow – and remain on the relatively cool surface forever. "Imagine on Earth if you had no mechanism to evaporate water, it would never rain," says Vivien Parmentier of the Côte d'Azur Observatory in Nice, France.

Now he and colleagues have created a more detailed 3D computer model that shows that the snow can become a gas again as it falls and the temperature and pressure increase. Strong updraughts can then blow the titanium oxides back to the upper atmosphere. "The gas can come back on the top layers and snow again and again," says Parmentier.

Snowfall on HD 209458b would be like none you've ever seen. Though titanium dioxide is white and shiny, for example, the snowflakes would also contain silica oxides from the atmosphere, making them black. Since the atmosphere is also dark, snowstorms on the planet would be a smoky affair, the opposite of the white-outs we get on Earth. "It would be like being in the middle of a forest fire," says Parmentier.

Although the team studied a particular hot Jupiter, their model should apply equally to other planets of this type, suggesting hot snow is a common occurrence. Parmentier says we may have already spotted snow clouds on another hot Jupiter, HD 189733b, as spectral analysis of the planet suggests the presence of microscopic particles in its atmosphere.

David Sing of the University of Exeter, UK, who helped identify such particles on HD 189733b, says the team's new model goes a long way to explaining how titanium oxides behave on hot Jupiters. "We're pretty used to water condensing on Earth; there it is titanium because the temperatures are so much hotter."

Hot, black snow – now that would be something to wake up to.

Reference: http://arxiv.org/abs/1301.4522

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Swarm-mongering: Brainless blobs flock together

Birds of a feather flock together and now so do brainless, inanimate blobs. Made of microscopic particles, the artificial swarms could shed light on the mysterious mechanisms behind the natural swarming seen in fish and birds. They might also lead to materials with novel properties like self-healing.

Animals such as birds, fish and even humans that move together in swarms have individual intelligence, but Jérémie Palacci of New York University and colleagues wondered whether inanimate objects could also swarm. "From a physicist's point of view, if many different systems behave in the same way there must be an underlying physical rule," he says.

To explore this idea, the team created microscopic plastic spheres, each one with a cubic patch of haematite, an iron oxide, on its surface. When submerged in hydrogen peroxide, the spheres spread out in a disordered fashion. The team then shone blue light on the particles, causing the haematite cubes to catalyse the breakdown of any nearby hydrogen peroxide into water and oxygen. As hydrogen peroxide concentration dropped temporarily in these regions due to the reaction, osmotic forces cause more hydrogen peroxide to flow into them, and that in turn buffets the spheres. The whole process then repeats.

Self-healing swarm

When two spheres come close enough to each other, the balance of chemical forces shifts so that the two spheres are attracted. If there are enough spheres in the same place they will cluster together to form shapes of symmetrically arranged particles, which the team call crystals (see video, above). These crystals continue to be buffeted by the movement caused by the breakdown of hydrogen peroxide – but now they move together as one object, replicating a life-like swarm. Switch off the light, however, and the reaction stops, causing the crystal to lose the forces that hold it together, and the particle distribution becomes disordered once again.

"This system shows that even though the particles have no social interaction or intelligence, you can exhibit collective behaviour with no biology involved," says Palacci. Since the haematite is magnetic, it is even possible to steer the crystals in one direction by applying a magnetic field. Such control might be useful if the artificial swarms are to be harnessed for applications.

As the particles automatically fill any gaps that form in the crystal, again thanks to the chemical dynamics of the system, they could be used to create a self-assembling, self-healing material. The work is published in the journal Science today.

Schooled by fish

Iain Couzin of Princeton University says these kinds of systems are very useful for studying biological collective behaviour because researchers have complete control over their interactions – unlike natural systems.

His team has its own swarming experiment published in the same issue of Science, based on schools of fish that prefer to stay in shade. Their paper shows that shining a light on some of the fish in the school causes them to speed up, to get away from the light. But as a result, non-illuminated fish also speed up, even though, if acting purely as individuals, they would have had no reason to do so. "We show just by using simple interactions that schools can have a sense of responsiveness to the environment that individuals do not have," he says.

Couzin sees no reason why such behaviour should be limited to natural systems. "In future it may be possible to create systems of particles that can make collective decisions – something we often think of as only possible in biological systems," he says.

Journal references: Living crystals: Science, DOI: 10.1126/science.1230020; Fish: Science, DOI: 10.1126/science.1225883

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Today on New Scientist: 30 January 2013

Timbuktu's precious scientific texts must be saved

Islamist militants in Mali have burned documents that attest to science in Africa before European colonisation - what remains must be protected

Think that massage feels good? Try adding drugs

Nerve bundles that respond to stroking have been identified and chemically activated in mice

How Obama will deliver his climate promise

The US is set to meet - and maybe exceed - Obama's pledge to cut US emissions by 17 per cent, which could give a boost to international climate talks

Minimum booze price will rein in alcohol abuse

Evidence suggests the UK government's proposal to set a minimum price for alcohol could save thousands of lives, and billions of pounds of public money

First real time-travel movies are loopers

Hollywood has played with time travel for decades, but now physicists have the first movies of what travelling to the past actually looks like

Surfer rides highest wave ever caught

Garret McNamara of Hawaii claims to have ridden the highest wave ever caught by a surfer, a 30-metre monster off the coast of Nazaré, Portugal

Infrared laptop trackpad ignores accidental touches

Longpad is a touchpad that extends the full width of your laptop and uses infrared sensors to ignore any unwanted touches

Close call coming: Averting the asteroid threat

With an errant space rock heading this way, just how good are our asteroid defences - and how do we avert the cataclysm?

The right to fight: women at war

The US military has accepted women into combat. What can science tell us about how women deal with being in the line of fire? And are they any different to men?

Earth and others lose status as Goldilocks worlds

Several planets are taking a hit thanks to a redefinition of the habitable zone - the area around a star in which liquid water can theoretically exist

The 10,000-year bender: Why humans love a tipple

Our taste for alcohol results from an evolutionary tussle between humans and yeast - one in which the microbes have often had the upper hand

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Today on New Scientist: 29 January 2013

Creatures of the air caught in the mist

Photographer Todd Forsgren uses mist nets to briefly ensnare a variety of tropical South American birds before releasing them, unharmed

Drug reduces enlarged prostate with few side effects

Shrinking enlarged prostates by blocking a potent growth factor could avoid problems - such as erectile dysfunction - that accompany current treatments

Climate change blamed for Australia's extreme weather

Floods have hit the east coast of Australia before recent bush fires have been put out, giving people a taste of climate change's possible consequences

Midnight sun: How to get 24-hour solar power

Rust may be the scourge of electronics but it could help solar power run all night

The most beautiful explanations

The 2012 Edge questions asked for great thinkers' favourite explanations. This Explains Everything collects them all into a fascinating read

Netted Costa Rican birds pay small price for art

Only mildly traumatic, mist nets offer an easy and safe way to catch birds for artistic, and ecological, study

Iran launches monkey into space

The Iranian Space Agency claims to have launched a rhesus monkey into space on a sub-orbital flight, and returned it safely to Earth

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Iran launches monkey into space

Lisa Grossman, physical sciences reporter

Last summer, the Iranian Space Agency announced their plan to send a monkey into space - and now they've apparently done it.

According to Iranian state-run television, a press release on the space agency's website, and photos of the event, Iran sent a live rhesus monkey into sub-orbital space aboard a small rocket called Pishgam, or Pioneer. There's even a video posted on YouTube that appears to be of the launch (though New Scientist could not confirm its authenticity).

The report has not been confirmed independently, however, and the US air force's North American Aerospace Defense Command (NORAD) has not reported seeing any missile launches from Iran.

But independent observers say the launch looks legitimate.

"Really, I see no reason not to take their word for it," says Jonathan McDowell, an astronomer at the Harvard-Smithsonian Center for Astrophysics who also keeps a log of space launches. He says he's convinced by the photos and discussions he's had with several knowledgeable source in online forums.

In photos released on the Iranian Space Agency's website, the rocket looks like the same kind the agency has launched before, but with a larger nose cone designed to fit a small chamber that can support life. Images also showed a live rhesus monkey strapped to a small seat.

The reports say the rocket went straight up 120 kilometres, which McDowell says qualifies as outer space, but not high enough to reach orbit, and came back down with a parachute.

It's unclear exactly when the launch took place. The press release says that the launch happened on the birthday of Mohammed the Prophet, which is celebrated by Shiites on 29 January, but was celebrated last week elsewhere in the world.

Some countries worry that Iranian rockets capable of carrying animals or people could also carry weapons. Iran has denied any military intention.

"This is not a scary thing because this is not a big new rocket that could hit America or anything like that," McDowell says. "There's nothing military to this. It's purely for propaganda. Nevertheless, it advances their science and their technology by being able to do it."

Iran says the launch is a first step towards sending humans into space, which they intend to do in the next 5 to 8 years. To do that, McDowell says, they'll need to build a larger rocket. The country currently has a vehicle called Safir that has successfully put satellites in orbit, and is developing a more powerful launcher called Simorgh.

The next step will probably be to either launch Safir to carry a human to sub-orbital space, or an unmanned Simorgh flight into orbit to make sure mission controllers can return it to the ground safely.

"They don't want to repeat what the Soviets did" in 1957, McDowell says, "which is put a living being in orbit before you figure out how to get it back."

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DNA privacy: don't flatter yourself

The secrets contained in our individual genomes are less valuable than we like to believe

IMAGINE donating your DNA to a project aimed at discovering links between genes and diseases. You consent to your genome sequence being released anonymously into the public domain, though you are warned there is a remote possibility that it might one day be possible to link it back to you.

A few years later, that remote possibility comes to pass. How should you feel? This is no longer a hypothetical scenario. About 50 people who participated in a project called 1000 Genomes have been traced (see "Matching names to genes: the end of genetic privacy?").

The researchers' intentions were honourable. They have not revealed these identities, and the original data has been adjusted to make a repeat using the same technique impossible. All they wanted to do was expose privacy issues.

Consider them exposed. It is clear that genomics has entered a new phase, similar to that which social media went through a few years ago, when concerns were raised about people giving away too much personal information.

What happens when the same applies to our DNA? Having your genome open to public scrutiny obviously raises privacy issues. Employers and insurers may be interested. Embarrassing family secrets may be exposed.

But overall, personal genetic information is probably no more revealing than other sorts. In fact there are reasons to believe that it is less so: would an insurance company really go to the trouble of decoding a genome to discover a slightly elevated risk of cancer or Alzheimer's disease?

The available evidence suggests not. In 2006, Harvard University set out to sequence the genomes of 100,000 volunteers and make them publicly available, along with personal information such as names and medical records. One of the goals was to see what happens when such data is open to all. The answer seems to be "not a lot". So far this Personal Genome Project has published 148 people's full genomes. Not one volunteer has reported a privacy issue.

This is not a reason for complacency, but it suggests that our genomic secrets are less interesting to other people than we might like to believe.

If you would like to reuse any content from New Scientist, either in print or online, please contact the syndication department first for permission. New Scientist does not own rights to photos, but there are a variety of licensing options available for use of articles and graphics we own the copyright to.

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Get cirrus in the fight against climate change

FEATHERY cirrus clouds are beautiful, but when it comes to climate change, they are the enemy. Found at high-altitude and made of small ice crystals, they trap heat - so more cirrus means a warmer world. Now it seems that, by destroying cirrus, we could reverse all the warming Earth has experienced so far.

In 2009, David Mitchell of the Desert Research Institute in Reno, Nevada, proposed a radical way to stop climate change: get rid of some cirrus. Now Trude Storelvmo of Yale University and colleagues have used a climate model to test the idea.

Storelvmo added powdered bismuth triiodide into the model's troposphere, the layer of the atmosphere in which these clouds form. Ice crystals grew around these particles and expanded, eventually falling out of the sky, reducing cirrus coverage. Without the particles, the ice crystals remained small and stayed up high for longer.

The technique, done on a global scale, created a powerful cooling effect, enough to counteract the 0.8 °C of warming caused by all the greenhouse gases released by humans (Geophysical Research Letters, DOI: 10.1002/grl.50122).

But too much bismuth triiodide made the ice crystals shrink, so cirrus clouds lasted longer. "If you get the concentrations wrong, you could get the opposite of what you want," says Storelvmo. And, like other schemes for geoengineering, side effects are likely - changes in the jet stream, say.

Different model assumptions give different "safe" amounts of bismuth triiodide, says Tim Lenton of the University of Exeter, UK. "Do we really know the system well enough to be confident of being in the safe zone?" he asks. "You wouldn't want to touch this until you knew."

Mitchell says seeding would take 140 tonnes of bismuth triiodide every year, which by itself would cost $19 million.

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Today on New Scientist: 25 January 2013

Hagfish gulped up in first video of deep-sea seal hunt

Watch the first sighting of a seal's underwater eating habits spotted by a teenager watching a live video feed

World's oldest portrait reveals the ice-age mind

A 26,000-year-old carved ivory head of a woman is not just an archaeological find - a new exhibition in London wants us to see works like this as art

Dung beetles navigate using the Milky Way

Forget the Pole Star: on moonless nights dung beetles use the Milky Way to follow a straight path with their dung ball

Stress's impact can affect future generations' genes

DNA analysis has yielded the first direct evidence that chemical marks which disable genes in response to stress can be passed on to offspring

Uncharted territory: Where digital maps are leading us

The way we use maps is evolving fast, says Kat Austen, and it will change a great deal more than how we navigate

Feedback: Tales of the stony turd industry

Fossilised faeces in Shitlington, confusing railway notices, organic water, and more

Duolingo gives language learning a jump start

First evidence that Duolingo, a new website that helps you learn a language while translating the web, actually works

Dolphins form life raft to help dying friend

A group of dolphins was caught on camera as they worked together to keep a struggling dolphin above water by forming an impromptu raft

Zoologger: Supercool squirrels go into the deep freeze

Hibernating Arctic ground squirrels drop their body temperatures to -4 °C, and shut their circadian clocks off for the winter

Greek economic crisis has cleared the air

The ongoing collapse of Greece's economy has caused a significant fall in air pollution, which can be detected by satellites

Body armour to scale up by mimicking flexible fish

Armour that is designed like the scales of the dragon fish could keep soldiers protected - while still letting them bend

Astrophile: Split personality tarnishes pulsars' rep

Pulsars were seen as cosmic timekeepers, but the quirky way in which one example shines suggests we can't take their behaviour for granted

Shrinking proton puzzle persists in new measurement

The most precise experiment yet to find the proton's radius confirms that it can appear smaller than our theories predict - is new physics needed?

Tight squeeze forces cells to take their medicine

A short sharp squash in these channels and a cell's membrane pops open - good news when you want to slip a molecule or nanoparticle in there

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Shrinking proton puzzle persists in new measurement

A puzzle at the heart of the atom refuses to go away. The most precise measurement yet of the proton's radius confirms that it sometimes seems smaller than the laws of physics demand – an issue that has been hotly debated for two years.

The latest finding deepens the need for exotic physics, or some other explanation, to account for the inconsistency. "If we were in a hole before, the hole is deeper now," says Gerald Miller of the University of Washington in Seattle, who was not involved in the new measurement.

The saga of the proton radius began in 2010, when a group led by Randolf Pohl at the Max Planck Institute of Quantum Optics in Garching, Germany, determined the width of the fuzzy ball of positive charge – and found it was smaller than had been assumed.

Previous teams had inferred the proton's radius, which is impossible to measure directly, by studying how electrons and protons interact. One method uses the simplest atom, hydrogen, which consists of one electron and one proton. A quirk of quantum mechanics says that an electron in an atom can only orbit its proton at certain distances, corresponding to different energy levels. The electron can jump between levels if it absorbs or releases energy in the form of a photon of light.

Ball of charge

By measuring the energy of photons emitted by an excited hydrogen atom, physicists can figure out how far apart the energy levels are, and thus the distances of the permitted electron orbits. A theory called quantum electrodynamics then allows them to calculate how far the proton's ball of charge must extend to keep the electrons at those distances.

This method gave a charge radius for the proton that was about 0.877 femtometres, less than a trillionth of a millimetre.

Pohl and colleagues used a novel method. They created an exotic version of hydrogen that replaces the electron with a muon, a particle that has the same charge as the electron but is 200 times heavier. Its extra bulk makes it more sensitive to the proton's size, meaning radius measurements based on muons are orders of magnitude more precise.

The new method didn't just make the measurements more precise. It also changed them: the muonic hydrogen gave a radius of 0.8418 femtometres, 4 per cent less than before.

Scandalous result

That might not sound like much, but in the world of particle physics, where theory and experiment can agree to parts in a billion, it was scandalous. A lively discussion sprang up, with some physicists claiming problems with Pohl's experiments and interpretations, and others suggesting gaps in the standard model of particle physics.

Pohl and colleagues have now repeated their experiment. The measurement of the radius is now even more precise than in 2010 – and it is still 4 per cent smaller than the value from hydrogen-based experiments.

Pohl reckons that there are three likely explanations. His experiment could have errors, although the confirmation makes that less likely. Alternatively, the electron experiments could be off. "This would be the most boring possibility," says Pohl.

The third, and most exciting, possibility is that muons do not interact with protons in the same way as electrons. In other words, the proton's apparent radius changes a little bit depending on which particle it is interacting with.

If true, that might require the existence of unknown particles that alter the way the muon interacts with the proton. Those particles could, in turn, solve some of the problems with the standard model of particle physics. They could, for instance, provide a candidate for dark matter, the mysterious stuff that makes up more than 80 per cent of the mass in the universe.

Monumental idea

Miller, Pohl and Ron Gilman of Rutgers University in Piscataway, New Jersey helped organise a workshop with 50 proton experts in Trento, Italy, last October to hash out the details of the problem – and arrived at a verdict of sorts. "Because the muon experiments seem to be so solid, the most popular answers were that there's some beyond-the-standard-model physics differentiating between muon and electron, which would be very important," Gilman says.

"That would be monumental, truly," Miller says.

But Miller also has a less radical suggestion, which could reconcile all the measurements without invoking new particles. According to quantum electrodynamics, two charged particles can interact with each other by exchanging a photon – it's as if they spontaneously create a basketball and throw it between them, he says.

The equations also allow for a more complicated interaction where the particles create two balls, and juggle them. Until now this type of interaction was considered too rare to be important, but Miller reckons that the muon's greater mass could make it a better juggler. That would strengthen the proton's interaction with it and make the proton look smaller to the muon without requiring any new physics.

All these ideas will be up for review in a few years' time when new experiments, including shooting muons at protons to see how they scatter and building muonic helium atoms to measure their energy levels, are completed.

"It's quite likely that through other experiments, in two to three years we might get an end to this," Miller says. "It shouldn't take forever."

Journal reference: Science, DOI: 10.1126/science.1230016

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Wallace: Wonders of nature have been solace of my life

Alfred Russel Wallace discovered natural selection independently of Charles Darwin. Through his letters, available online for the first time, he tells us of his research, expeditions and enduring fascination for nature's mysteries.

You are famously joint author, with Darwin, of the first paper describing the origin of species and natural selection, published in 1858. When did you first get the idea?
I begin [in 1847] to feel rather dissatisfied with a mere local collection – little is to be learnt by it. I sh[ould]d like to take some one family, to study thoroughly – principally with a view to the theory of the origin of species. By that means I am strongly of [the] opinion that some definite results might be arrived at.

This desire led you to Brazil to collect birds, butterflies and beetles to try to discover what drives the evolution of new species. Were there any incidents on the voyage?
On Friday the 6th of August [1852]… the Captain (who was the owner of the vessel) came into the cabin & said "I am afraid the ship's on fire. Come & see what you think of it."

Despite that harrowing experience, you next undertook an 8 year expedition to the Malay Archipelago, where you discovered the invisible boundary between the animals of Asia and the Australian region, which would later be called the Wallace Line in your honour. What fascinated you most on that trip?
The Birds have however interested me much more than the insects, they are proportionally much more numerous, and throw great light on the laws of Geographical distribution of Animals in the East… As an instance I may mention the Cockatoos, a group of birds confined to Australia & the Moluccas, but quite unknown in Java Borneo Sumatra & Malacca… Many other species illustrate the same fact.

You have been famously good-natured about sharing the discovery of natural selection with Darwin…
I also look upon it as a most fortunate circumstance that I had a short time ago commenced a correspondence with Mr. Darwin on the subject of "Varieties", since it has led to the earlier publication of a portion of his researches & has secured to him a claim to priority which an independent publication either by myself or some other party might have injuriously effected

What did you and Darwin have in common?
In early life both Darwin and myself became ardent beetle-hunters. Both Darwin and myself had, what he terms "the mere passion of collecting"… Now it is this superficial and almost child-like interest in the outward forms of living things, which, though often despised as unscientific, happened to be the only one which would lead us towards a solution of the problem of species.

Do you feel your contribution has been overlooked?
The idea came to me, as it had come to Darwin, in a sudden flash of insight: it was thought out in a few hours – was written down with such a sketch of its various applications and developments… then copied on thin letter-paper and sent off to Darwin – all within one week.

I should have had no cause for complaint if the respective shares of Darwin and myself in regard to the elucidation of nature's method of organic development had been thenceforth estimated as being, roughly, proportional to the time we had each bestowed upon it when it was thus first given to the world – that is to say, as 20 years is to one week.

You helped Darwin with the puzzle of bright colouration in animals, which led to the concept of warning colours. To ask his question again, why are some caterpillars so brightly coloured?
[Since some]… are protected by a disagreeable taste or odour, it would be a positive advantage to them never to be mistaken for any of the palatable caterpillars… Any gaudy & conspicuous colour therefore, that would plainly distinguish them from the brown & green eatable caterpillars, would enable birds to recognise them easily as a kind not fit for food, & thus they would escape seizure which is as bad as being eaten.

How did you feel looking back on your life's work, at the age of 89?
The wonders of nature have been the delight and solace of… life. Nature has afforded… an ever increasing rapture, and the attempt to solve some of her myriad problems an ever-growing sense of mystery and awe.

Do you have a message for our readers?
I sincerely wish you all some of the delight in the mere contemplation of nature's mysteries and beauties which I have enjoyed.

If you would like to reuse any content from New Scientist, either in print or online, please contact the syndication department first for permission. New Scientist does not own rights to photos, but there are a variety of licensing options available for use of articles and graphics we own the copyright to.

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