2 June 2012 | NewScientist | 5

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WHERE’S a scientific genius when you need one? Isaac Newton saved the UK economy the equivalent of millions of pounds by standardising its gold coins.

Newton spent the last 30 years of his life running the Royal Mint, which makes the country’s coins. Ari Belenkiy at the British Columbia Institute of Technology in Vancouver, Canada, has now compared coins made before and after Newton’s stint at the mint.

At the time, gold coins varied in weight. Canny goldsmiths would buy coins – which often weighed slightly more than their face value – melt them down and sell the gold on at a profit.

Belenkiy’s analysis of coin weight, and notes made by Newton, suggest he reduced the standard deviation from around 85 milligrams to 49 (Journal of the Royal Statistical Society, DOI: 10.1111/j.1467-985X.2012.01037.x).

We don’t know exactly how he did this, but Belenkiy suggests that Newton may have reduced variability by applying his recently derived “cooling law” to slow the coins’ cooling. Belenkiy calculates the improvements saved up to £10 million in today’s currency.

Newton’s gold trick

CHILDREN and workers exposed to radioactive fallout from the Fukushima Daiichi nuclear disaster last year can breathe a sigh of relief – most received low doses of radiation. However, the health of some workers will need close monitoring in the future.

These are the main conclusions of an interim report on the health impacts of fallout from Fukushima issued last week in Vienna, Austria, by the UN Scientific

Committee on the Effects of Atomic Radiation. “For the time being, we don’t see anything of major concern,” says Wolfgang Weiss, committee chairman. “The levels of exposure are much lower than what we saw at Chernobyl.”

The committee evaluated data on radiation absorbed by the population. The report reveals that children in villages with the heaviest fallout received relatively modest doses, although most exceeded a safe annual cumulative dose for workers in the industry.

Monitoring of radioactive iodine in the thyroid glands of 1080 children under 15 revealed that none received doses at

levels likely to cause cancer.However, 167 workers received

doses exceeding 100 millisieverts. Of these, six exceeded 250 millisieverts – the equivalent to 12 years of the maximum dose that is considered acceptable within the industry. Two others received 680 millisieverts. These workers will all need careful monitoring, says Weiss.

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Déjà vu clueFeel as if you’ve read this before? Brain scans of 87 people who say they experience déjà vu showed less grey matter in an area of the brain responsible for memory, compared with 26 who didn’t experience it. This anatomical difference is likely to be a consequence of altered connectivity in the region, which might also be the cause of the faulty recall (Cortex, DOI: 10.1016/j.cortex.2012.03.004).

Ancient inequalityBlame the Stone Age for the 1 per cent. Unequal distribution of wealth dates back at least 7000 years, to the first European farmers. Archaeologists found that males buried with stone tools had access to the best land, suggesting property and land were passed down through families (Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.1113710109).

A useful donationBlood donation is good for your health as well as your conscience. A group of 33 overweight adults who gave blood twice, a month apart, saw their risk of stroke fall by 40 per cent and heart attack by 20 per cent through decreased blood pressure, compared with those who didn’t give blood (BMC Medicine, in press).

Italian quakeJust nine days after a magnitude-6.0 earthquake hit Italy, the country has experienced two more quakes, killing at least seven people. The larger of the two, a magnitude-5.8 quake, struck at 9 am local time on Tuesday. The region is tectonically active because the African plate is pushing north into Europe.

Roots of denialWhatever motivates climate sceptics, it isn’t ignorance of science. People who don’t believe in global warming are just as scientifically knowledgeable as people who accept it (Nature Climate Change, DOI: 10.1038/nclimate1547).

–Japanese children get the all-clear–

The kids are alright

The fish are alightTHEY’RE not hot enough to harm you, but some tuna still carry radioactive caesium from the leak at Japan’s Fukushima Daiichi plant last March. This creates an opportunity to track some elusive marine animals.

Daniel Madigan of Stanford University in California found detectable levels of a radioactive caesium isotope in 15 Pacific bluefin tuna (Thunnus orientalis) off the coast of San Diego, California, in August 2011. The fish, which migrate across the Pacific Ocean, can pick up caesium from the water they swim in and the food they eat. The isotope was not detected in fish that were caught before 2011.

Tuna migration patterns are well known, but Madigan hopes that such radiation may aid the tracking of other species like salmon sharks (Lamna ditropis) and some turtles and seabirds.

60 SecoNdS

–Nuclear boss targeted–

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“In Newton’s time, gold coins varied in weight, and canny goldsmiths would profit from this”

“For now, we don’t see anything of major concern. exposure was much lower than we saw at chernobyl”

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