September 28, 2017 at 07:41PM

Today I learned: 1) ...about Stéphane Leduc's experiments in osmotic growth. Back in the 1910s, Leduc (and, I gather, a few others before him) discovered that if you put a seed crystal of one salt in a solution that's highly saturated with another salt, you can make a "cell" whose membrane is a layer of flexible, colloidally-precipitated salts. Osmotic pressure causes the "cell" to grow, sometimes in quite fantastic shapes... including many that are startlingly similar to living organisms we're familiar with. Leduc came up with osmotic growth recipes for single cells, cell colonies, ferns, mushrooms (complete with caps and gills), trees, tube worms, shells, and other things. Leduc actually hoped to show that osmotic pressure was the fundamental force responsible for life. In that, he was grossly mistaken. It's something of a cautionary tale for fundamental biologists, or even scientists in general... just beacuse you have a simple model that reproduces the patterns of a phenomena DOES NOT mean that you know what causes that phenomena. (On the other end of the spectrum, there are Turing patterns, which as far as I know were a) totally mathematical structures that b) turned out to be quite descriptive of things like shell and fur patterning.) Check out some photographs of Leduc's growths here: http://ift.tt/2x0uFC1 If you want to know more, you can read Leduc's book on the subject here: http://ift.tt/2wmfIdJ. I've only read a small excerpt, so I can't speak to the whole book, but it's worth at least looking through the plates -- he took some really gorgeous photos of crystal growths. He also gives a few recipes in chapter 12, so if you want to do these yourself, you can (some of those salts are toxic, though -- DO NOT mix the salts with or on anything you're going to use for cooking!). 2) Arrow's Information Paradox, a, uh, theorem of economics? A hypothesis of economics? Anyway, Arrow's Information Paradox deals with the supply and demand of information as a good. The paradox is that it's very hard to know how valuable a piece of information will be unless you know the information. So if some kind of information is available in an open market, and you're trying to decide whether or not you should buy it, there's no great way to decide without getting the information, which you can't do without buying it. The net result is that a free market is likely to mis-supply (probably under-supply?) information. Arrow's Information Paradox is one argument that knowledge should be treated as a public good and funded accordingly. 3) Wikipedia has a fairly pretty severe gender balance problem -- only about a third of Wikipedia visitors and only about 10-15% of Wikipedia editors are female. I was quite surprised about this. There are a whole bunch of interesting nuances to this overall fact -- for more, check out Wikipedia's article on gender bias on Wikipedia: http://ift.tt/1AnbVMx