Notes, May 1st

Mutation Tracking

Interesting article from the New York Times on tracking the spread of C19 by looking at genetic mutations in samples from various places.

That combination of old and new mutations suggested that the student did not acquire the coronavirus from someone who had recently arrived from another country. Instead, the coronavirus was probably circulating undetected in the Seattle area for about five weeks, since mid-January.

Since then, viruses with a genetic link to the Washington cluster have now appeared in at least 14 states and several countries around the world, as well as nine cases on the Grand Princess cruise ship.

Mobile Positioning

With various countries rolling out apps to assist with contact tracing, here’s a look at the various ways to determine position from a mobile phone and why Bluetooth makes the most sense for those apps.

This tells you not much – if anything at all about absolute location, but it does tell you about proximity with high confidence and decent precision and isn’t as creepy as RRLPing the planet. That sounds like what we’re after and there’s a good reason the Singaporean health ministry, NHSX, the Apple/Google joint project, and a bunch of others have converged on solutions that use BLE plus public-key cryptography. It does have some problems – notably, as Ross Anderson points out, it’s still radio and it doesn’t care if you were on opposite sides of double glazing, and there are complicated platform restrictions in Apple iOS to stop you being creepy and weird with it.

Humanity

Finally, Tim Harford has a nice reminder that despite all the stories of bad behaviour, the vast majority of people are actually well-behaved in a crisis

…a mere 3 per cent of shoppers had bought “extraordinary amounts” of pasta. Most of us were merely adjusting our habits to life spent away from restaurants, sandwich bars and offices with their own loo paper. We all went shopping a bit more often, and when we did, spent a little more. No cause for collective shame, but it was enough to strain supermarket supply chains.

What about those who ignore pleas to keep their distance? Again, the misdeeds are exaggerated. Lambeth council grumpily closed Brockwell Park in south London, complaining of 3,000 visitors in a single day — not mentioning that the park might easily see 10 times that number on a normal sunny Saturday, nor that taking exercise in a park is perfectly permissible.