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Let’s talk about X

x

It’s an unpresupposing little letter, $x$. In fact, that’s the reason we use it to represent something we don’t know. But how do you write it down? When Vijay Krishnan tweeted a link to an American college professor’s page on mathematical handwriting, I was shocked to learn that he thought adding a hook to a simple cross was sufficient to differentiate letter-$x$ from times-$\times$.

So I asked our Twitter followers how they write $x$. The Cambrian explosion of diversity in answers I received was eye-opening – I’m glad I asked!

‘RightingBot’ simulates the way lizards right themselves when falling

RightingBot

RightingBot. Credit: Tom Libby

Lizards, just like cats, have a knack for landing on their feet when they fall. But unlike cats, which twist and bend their torsos to turn in the air, lizards swing their large tails one way to rotate their body the other, according to a recent study. And the longer the tail, the smaller the movement needed. The study used high-speed video, developed a mathematical model and finally used this to develop a lizard-inspired robot, called ‘RightingBot’, which replicates the feat.

Out-of-work economists will probably not turn to bank robbery

Three economists decided to examine bank robbery as an economic activity. They were given access to data from the British Bankers’ Association on the amounts stolen during robberies, pretended to be statisticians for a bit, and came up with some interesting results. They’ve written up their findings in a feature article in the June edition of Significance.

Photo courtesy Orange County Archives.

Redrawing the map of Great Britain from a network of human interactions

This is just about the most right-on, 21st-century paper and associated PR I’ve seen this year. MIT’s SENSEable City Lab has produced this little video to go with a paper by some of their researchers, led by Carlo Ratti:

[youtube url=http://www.youtube.com/watch?v=e-hlP8Ql384]

So we have a slickly produced YouTube video announcing an open-access paper about big data with a trendy creative commons 8-bit music track behind it. I don’t know whether to applaud them on a job well done or to have an adverse reaction against that much political correctness and PR budget in one place.

Some Turing-related articles free to read for a short period of time, thanks to T&F

Taylor & Francis have generously made some articles related to Alan Turing from their archives freely available until the end of the year. They’re calling it the Alan Turing Centenary Collection, and it includes two reports written by Turing during the war, a few articles which they claim are “about Alan Turing”, and a 1978 article by 2011 Alan Turing Prize winner Judea Pearl. Grab them now, while you can.

They’re also offering 20% discounts on the books The Computer Science Handbook, The Universal Computer: The Road From Leibniz to Turing, and Bright Boys: The Making of Information Technology if you enter the code 193CM at the checkout.

T&F have made a PDF leaflet with descriptions and links to all the material in the collection. Rather cheekily, the second page of the leaflet contains a list of related articles which you might assume to be part of the collection. In fact, they’re still ambitiously priced at £27 each.

(via @AlanTuringYear on Twitter)