Category: Calculatin’
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The puzzling beauty of Abelian sandpiles
Pour real sand, a grain at a time, onto a flat surface and the result is a rather dull pyramidal shape. but in the mathematical world, the result is a little different. The image above is produced using a theoretical model called an Abelian sandpile model. It is produced by dropping some 200,000 grains onto…
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Schroedinger-like PageRank wave equation could revolutionise web rankings
The PageRank algorithm that first set Google on a path to glory measures the importance of a page in the world wide web. It’s fair to say that an entire field of study has grown up around the analysis of its behaviour. That field looks set for a shake up following the publication today of…
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How likely is an avian flu pandemic?
With winter approaching, many governments in the northern hemisphere are stocking up on Tamiflu and fine tuning their civil defense plans to cope with the disruption a bird flu outbreak might cause. But how likely is an outbreak? While various groups have written about how a pandemic might happen, Rinaldo Schinazi at the University of…
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The puzzling wrinkles in graphene
Last year, Jannick Meyer at the Max Plank Institute for Solid State Research in Stuttgart and pals discovered that single sheets of graphene are gently rippled, like the rolling hills of New England. That’s a puzzle because graphene behaves like a perfect 2D crystal. So how do these ripples form and what role do they…
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How to build a warp drive
Is faster than light travel allowed by the laws of physics? There’s no harm in speculating, right? In 1994, Michael Alcubierre, a physicist at the National Autonomous University of Mexico in Mexico City, put warp drive on a firm (-ish) theoretical footing for the first time. His thinking was that what relativity actually prevents…
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The curious kernels of dictionaries
If you don’t know the meanng of a word, you look it up in the dictionary. But what if you don’t know the meaning of any of the words in the definition? Or the meaning of any of the words in the definitions of these defining words? And so on ad infinitum. This is known…
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Group theory and spinal injuries
Medical science is stuck in the middle ages when it comes to understanding the causes of back pain and how to prevent it. If you want advice, “bend your knees when lifting” is all you’re likely to get. The standard theory describing spinal injuries is known as the principal loading hypothesis and assumes that any…
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Solar system filled with dark matter, say astronomers
As the evidence for dark matter builds, astronomers have begun modelling how it ought to be distributed around the cosmos. They’ve shown how it must be distributed on the largest scale to make clusters of galaxies form in the way we see, various other simulations show that it forms a kind of halo around galaxies…
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World’s oldest social network reconstructed from medieval land records
The network of links between peasants who farmed a region of small region of south west France called Lot between 1260 and 1340 have been reconstructed by Nathalie Villa from the Universite de Perpignan in France et amis. The team took their data from agricultural records that have been preserved from that time. This is…
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The mathematics of tackling tax evasion
In recent years, economists have gained the luxury of actually being able to test their ideas in experiments involving the behaviour of real people. And one particularly new and promising area of experimental economics focuses on tax evasion, which ought to be of keen interest to many governments around the world. A couple of years…