Mostly science, some physics teaching
The video shows artificial models of the key structures in a type of cell called a melanophore. This is from a nice paper by Aoyama et al. Melanophores and similar cells are how animals like chameleons change colour. The blobs that show up as bright here in the fluoresence microscopy images are actually dark brown under natural conditions. They contain eumelanin, the brown pigment that makes brown hair brown.
The title is fantastic but it is not mine sadly. I stole it from a paper by deShazo, Bigler and Skipworth. Thanks to them for that. The paper analysed chicken nuggets from fast food outlets. Spoiler alert: they don’t contain a lot what of would be conventionally regarded as chicken meat, although most of it did in the past belong to a chicken. Somewhere on a chicken’s body. Somewhere.
I have just started reading a classic book on how we think: Irrationality by Stuart Sutherland. It is 20 years old but has been reissued. As the title suggests it is about how we (all of us) routinely think and make decisions in a pretty dumb way. One of the most commons ways we mess up is due to what is called ‘availability error’. We make decisions based on the most immediate and striking facts available to us, the ones in the forefront of our minds. These striking facts are often unreliable and unrepresentative.
For the benefit of the younger readers I should say that this is a reference to the classic Blondie song. Video is here, you can click on it and read this post while listening to a real classic. I wrote it while listening to it more-or-less on a loop.
Below are the final exchanges from a piece on Thursday’s Today programme. Justin Webb is the Today presenter, Brian Hoskins is a scientist from Imperial College, and Nigel Lawson is the ex-Chancellor. It starts with Hoskins addressing the measurement (note that word, it will come up again) that although over the last 40 or so years we had significant global warming, the temperature rise (at the surface) looks to have slowed a bit over the last 10 to 15 years.
On Tuesday I went to one of the general evening physics run by the local group of the Institute of Physics, mainly Paul Stevenson and others on the committee. Future talks here. It was on climate change and the figure that really stood out for me in the talk is above. It is taken from the newly released physical science bit of the 5th report of the IPCC (Intergovernmental Panel on Climate Change). Basically it shows the temperature averaged over the whole of the Earth and over a decade of time, as a function of time. I.e., the average temperature in the 1980s, in the 1990s, etc. The y-axis is in ºC and is I think the difference in temperature in a decade relative to the average temperature between 1961 and 1990.
Correlation does not imply causation is a useful statement for a scientist to bear in mind. It is also good to remember it whenever a politician is claiming some statistic says their policy is a success, they are almost always using correlation to imply they their policy has caused the effect. The best way to see that correlation does not necessarily mean there is cause and effect, is to look at some examples of where two variables are correlated, i.e., where on a plot is one variable is changed so does the other, but where it would be very surprising if one causes the other. There are many examples of this, this paper goes for showing that as the USA imported more lemons from Mexico, fatalities on US highways dropped. Lemons are fine things, a slice of lemon is excellent in a G&T, but the only way they save lives if you have very bad scurvy.
Semester 2 starts on Monday, so I’m revising my lecture notes for my course on partial differential equations. This includes what is called the principle of superposition, which underlies what we know as the interference of waves. This picture (from a user called Spiralz on Wikimedia) shows interference off beautifully. Perhaps this is clearest on the left at about the same height as the ducklings, where the waves set up by the rear duckling intefers with that of its mother to produce a cross-hatched appearance on the water surface due to the addition (superposition) of the two waves going in different directions at that point. Beautiful physics, cute ducklings, what’s not to like.
Probably not, I wouldn’t. But neither of us are the brilliant but eccentric mathematician Grigori Perelman. On Friday I took our seminar speaker to lunch and we chatted about different perspectives on science and maths. The speaker is a mathematician at New York University (NYU), and briefly overlapped with Perelman when Perelman was at the Courant Institute at NYU. Perelman proved the Poincaré conjecture, a very important problem in maths. So important that it is one of the 7 Millenium Prize Problems, each of which has a $1 million prize. Incidentally, 5 of these are still unclaimed if you fancy a challenge.
Chance & Necessity 