UPFRONT

4 | NewScientist | 8 September 2012

FOR organic farmers, bad news comes in twos this week. Organic crops seem to be no more nutritious than conventional ones, and are not necessarily great for the planet either.

Crystal Smith-Spangler of Stanford University in California and colleagues put together 237 studies comparing organic and non-organic food. They found little evidence that organic food was more nutritious. Conventional foods contained more pesticides but were within permitted limits (Annals of Internal Medicine, vol 157, p 348).

Meanwhile, organic’s green credentials have been questioned by Hanna Tuomisto of Oxford

University and colleagues, who reviewed 109 papers. Organic farms were less polluting for a given area of land, but were often more polluting per unit of food produced. They did have better soil, though, and housed more species (Journal of Environmental Management, doi.org/h8v).

“An ‘organic’ label is not a straightforward guarantee of the most environmentally friendly product,” says Tuomisto.

Organic? Whatever

Cleaning up tarARE tar sands becoming a bit cleaner? For the first time, a carbon capture and storage (CCS) plant is going to lock away some of the carbon dioxide produced by refining the dirty oil. However, the oil will still lead to more emissions than conventional crude oil.

Tar sands contain bitumen, which is difficult to extract and must then be processed to produce crude. This means tar sands release about 17 per cent more greenhouse-gas emissions

Stem cells treat paralysisALL week, world records have been smashed by Paralympians. So what better time to announce another world first: stem cells have helped people paralysed from a broken spine to partially recover feeling.

Three people paralysed from the chest down have received injections of neural stem cells into their spinal cord. The cells, acquired from donated fetal brain tissue, were injected between four and eight months after injury, with a temporary course of immunosuppressants.

Before treatment, none of the three felt any sensation below their nipples. Six months after therapy, two of them had sensations between their chest and belly button. The third person has not felt any change.

“The fact we’ve seen responses to light touch, heat and electrical

impulses so far down in two of the patients is very unexpected,” says Stephen Huhn of StemCells, the company in Newark, California, developing the treatment. “They’re really close to normal in those areas now in their sensitivity,” he adds.

Armin Curt of Balgrist University Hospital in Zurich, Switzerland, where the three were treated, presented the results this week in London at the annual meeting of the International Spinal Cord Society.

There could be several reasons why stem cells improve sensitivity, says Huhn. They might restore myelin insulation in damaged nerves, improving communication to and from the brain. Or they could be enhancing the function of existing nerves, replacing them entirely or reducing the inflammation that hampers repair.

“Organic farms were often more polluting per unit of food produced, but they housed more species”

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Huhn hopes that the results will revive the enthusiasm that evaporated following last year’s suspension of the only other trial to test stem cells for spinal injury. “It is the first time we’ve seen some beneficial effect, so we’re moving in the right direction,” he says.

”These data certainly indicate that stem cells may remediate some of the functional loss associated with spinal cord injury,” says George Bittner, a neurobiologist at the University of Texas at Austin. However, Wagih El Masri of the Midlands Centre for Spinal Injuries in Oswestry, UK, warns that 3 per cent of people with spinal injury can see spontaneous improvements. He says that trials in people injured more than six months previously will help to confirm the results.

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8 September 2012| NewScientist | 5

overall than conventional oil (Environmental Research Letters, doi.org/cs56qs).

Shell plans to build a CCS plant at its Athabasca Oil Sands Project in Alberta, Canada, to capture emissions from bitumen processing. The Quest plant will come online in late 2015, and will store 1 million tonnes of CO2 underground each year, making it one of the world’s largest CCS plants.

However, the new CCS plant will not capture the extra CO2 generated by extracting the thick and sticky bitumen in the first place.

Never-ending storyIT LAUNCHED 35 years ago, but the most distant spacecraft from Earth is refusing to leave home turf. NASA’s Voyager 1 has seemed on the verge of exiting our solar system for years, but new results suggest that it still has a way to go before it enters interstellar space.

The solar system sits in a huge magnetic bubble. Solar wind containing charged particles flows outwards from the sun, only to get bent around by the magnetic field at the boundary between the solar system and interstellar space, which is known as the heliopause.

In 2010, readings indicated that Voyager 1 was near the heliopause because the solar wind speed dropped to zero. To confirm this, in 2011, mission managers commanded Voyager 1 to rotate 70 degrees for a few hours every other month. To their surprise, there was no change in the solar wind’s direction (Nature, DOI: 10.1038/nature11441 ).

Voyager scientist Robert Decker reckons the craft is in a transition zone not accounted for by current models and will cross the heliopause in 2014. But Gary Zank of the University of Alabama in Huntsville thinks the anomaly means the solar bubble has a thick shell that could keep Voyager 1 home for another 15 years.

Don’t feed the miceSLOPPY campers may have inadvertently triggered a viral outbreak that has killed two people and sickened four more who stayed at Yosemite National Park in California in June.

Sin Nombre hantavirus is carried by deer mice and can pass to people if they inhale dust containing dried mouse faeces.

A population of deer mice was found nesting inside the double walls of tent cabins occupied by those who have succumbed to the virus. Some 10,000 people have slept in the tents this summer,

and have been warned to watch for flu-like symptoms, which can take up to six weeks to show. The virus kills one-third of those infected, though infection is rare.

“If the tents were cleaned of foodstuffs each day, they would

be less attractive to rodents,” says Tony Schountz of the University of Northern Colorado in Greeley. The risk is still low, though. “This won’t dissuade me from visiting again.”

“Deer mice were nesting in the walls of tent cabins occupied by those who succumbed to the virus”

LAST Sunday, Paralympic favourite Oscar Pistorius was beaten to the gold medal in the T44 200-metre final by Brazilian Alan Fonteles Oliveira. Pistorius called the race unfair, saying Oliveira ran on excessively long blades that boosted his stride length.

To comply with regulations athletes must ensure their prostheses don’t convey an “unrealistic enhancement”, but double amputees are likely to pick blades as long as legally allowed to give them the best advantage. Oliveira increased the length of his by 4 centimetres, three weeks ago. Despite the extension, however, Pistorius’s strides were an average of 2.2 metres long, whereas Oliveira’s only averaged 2 metres.

The IPC stood by its decision to approve Oliveira’s blades, but have agreed to talk to Pistorius at a later date about his concerns. Others have less time for his argument, pointing out that the sprinter is thought to have kept his blades shorter in order to also qualify for the Olympics.

Pistorius has previously argued that he should be able to run in the Olympics as his blades don’t give him an advantage over non-disabled competitors. “Pistorius is now saying that you just need to lengthen your prosthetics to go faster, something non-amputees cannot do,” says Steve Haake at Sheffield Hallam University in the UK. He has “invalidated his reasons for being able to run” in both games, Haake says.

Double standards on the track

–Alan Oliveira won fair and square–

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Hot but not so botheredClimate change may be bad news for us humans, but it could be a boon for life in the long run. Marine fossil records from the last 540 million years suggest warmer climes increase biodiversity. Extinction rates go up, but new species can also flourish (Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.1200844109).

Mississippi backwardsWhen hurricane Isaac made landfall in Louisiana last week, it pushed the Mississippi into reverse. For nearly 24 hours on 28 August, the river flowed backwards up its channel, according to the US Geological Survey. The last reversal was the handiwork of Katrina in 2005.

Thalidomide apologyGrünenthal, the German firm that developed thalidomide to treat morning sickness, has apologised to those born with birth defects after their mothers took the drug. Martin Johnson, chairman of the UK Thalidomide Trust, criticises the apology because it doesn’t discuss what, if anything, Grünenthal knew about the drug’s ill effects before it was withdrawn.

Wolves of WyomingThe wolves in the US Rockies are all better, according to the Fish and Wildlife Service. It has decided that the Wyoming population has recovered and no longer needs protecting under the Endangered Species Act. The Montana and Idaho populations had already reached this milestone. The three states are collectively home to over 1700 wolves.

Stellar sprinklesNewborn stars can have a touch of sweetness. The ALMA telescope in Chile has for the first time found the simple sugar glycolaldehyde, a key ingredient of RNA, around a sun-like star. It’s the perfect spot for sugars to become part of future planets.

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