June 07, 2016 at 04:30AM

Today I Learned: 1) The Windsor Beauties are a set of 10 portraits from the 1660s of the the most beautiful women in the court of King Charles II. It seems Charles took after Zeus's style of rule, except he somehow didn't get into serious trouble with his wife...? In any case, wooing King Charles and bearing his children was an efficient way for a beautiful woman of the era to gain power, prestige, and a title, and many, many women pursued that path. 2) Teachers know way more about classroom politics than I thought. Also, high school is way more political than I remember. 3) ...what the inside of a PTC-100 Thermal Cycler (with heated bonnet) looks like! I had some fun repairing one of these today... by which I mean I reset a screw on one and failed to fix the lid.... The PTC-100 is, in my humble opinion, a quite well-put-together little thermal cycler. First off, it *is* quite little -- about the same overall size as a toaster oven, though taller and narrower. The lid detaches with two screws, which is probably necessary because it comes with two different lid types (one heated and one unheated). The heated lid has a heat plate that can be adjusted by a screw controlled by a plastic wheel accessible from the outside. The innards of the lid can be accessed by simply screwing down the heat plate until it falls out. Unfortunately, one of the PTCs I wanted to repair has a broken plastic-wheel-screwy-thingy on the lid... which means I can't really get into the lid to fix it... this is, I admit, something of a design flaw. The frame of the main body comes off with just four screws, exposing a board of electronics, a second board that seems to control I/O, and the thermal cycling block itself. The I/O board detaches from the frame with a single wire and from the other electronics with two more, but it's tethered to the thermal cycling block (and through it, the power supply) by a hot-glued power connector. Again, something of an annoyance. Everything else comes out quite nicely, though -- the power cycling block can be detached by taking out six screws accessible from the outside, and then it slides right out in one big piece. Very convenient. PTC-100s are all over Ebay, and they're pretty cheap for a thermal cycler ($150-$800). The interface is pretty clunky and outdated, but it works just fine, and if the two I got are any indication, it's a good line. I *have* heard that they have a tendancy to burn out... but they do have a pair of fuses that presumably can be replaced in just that event. Aaaand that's probably way more than you wanted to know about the PTC-100 thermal cycler. But you didn't come here for ordinary facts, did you?

June 06, 2016 at 01:25AM

Today I Learned: 1) ...about a proposed system of interstellar travel involving laser propulsion. This isn't a new idea at all, but I did learn some new tidbits, as well as a proposed *implementation* that's gotten some early-stage funding. The basic idea of laser propulsion comes roughly from the solar sail idea. The spacecraft would have (or be) a large solar sail, but instead of being powered by solar ejecta, it would be pushed by a laser, beaming power from Earth, Earth orbit, or some other, more convenient location. The nice thing about laser propulsion is that the spacecraft would require virtually no fuel -- all the actual power generation would occur at the launch site. The only problem is that you can't really decelerate at the other end... but it's the only vaguely-plausible mechanism we currently have for getting things to the speeds required for interstellar travel. One thing I didn't know about is that there's a recently-proposed project at NASA to actually build these things, along with a proof-of-concept grant to show that it could plausibly work. The *really* cool thing... well, there's a couple of cool things, but the *most* cool thing about this particular project is that it's designed to be *scalable* in the sense that NASA can start by building a small, kilowatt-scale laser for short-distance, low-mass flights, then scale it up by either building progressively larger lasers or building *more* of the small ones. That means there's a smooth path from proof-of-concept prototypes through dozen-gigawatt-scale interstellar probe launchers. The *other* really cool thing about the laser propulsion system is the sheer ridiculousness of what it can do once scaled up. The ultimate goal is to build a 50-100 gigawatt orbital laser (with a total mass of about 100 times that of the ISS) that would be capable of accellerating a wafer-thin, several-kg probe to about a quarter of the speed of light. In 10 minutes. At that speed, we could get a probe to Alpha Centauri in about 17 years after launch, which means we'd have telemetry from that probe about 21 years after launch. The younger among us could be hearing back from another star system *in our lifetimes*. 2) I've noticed while interacting with high schoolers on the subject of biology that I'm often surprised about what the students know... and also by what they don't know. That makes it really hard to teach effectively. Today I learned that this is one of the big known problems in teaching, and that there are a ton of tricks and tips out in the literature for getting around it. For example, I also learned today about the idea of an "exit ticket". In a class with an exit ticket, a student can't leave the class until they've filled out some kind of "ticket" with a problem solution, an answer to a question, or simply a self-evaluation of how well that student understood everything from the class. It's a simple way of getting some valuable feedback about what everyone knows, doesn't know, or thinks they know but don't. Thanks to Kamila Laliv Goldin for sending me down this educational path! 3) ...how to play Netrunner! It's a cyberpunk asymmetric strategy card game where one player takes on the role of a corporation, trying to advance corporate agendas, while the other player takes on the role of a hacker who tries to reveal, steal, or otherwise disrupt those agendas. There's a lot of hacking and a level of tech-speak I find quite pleasing. Thanks to Andrey Shur for teaching me!

June 05, 2016 at 02:46AM

Today I Learned: 1) Antifreeze proteins (proteins that protect the cell against freezing, intuitively enough) are remarkably diverse and have evolved many times in plants, animals, and bacteria (and probably other things I don't know about). They have a number of different mechanisms, but the most common function* appears to be to bind small ice crystals and block their growth. They also look kind of like space docks from Star Trek. Thanks Anders Knight! *NOT TO IMPLY TELEOLOGICAL PURPOSE 2) Credit reports can be obtained for free, a limited number of times per... year...? Credit *scores*, however, it seems require a fee to acquire. 3) Three ring carbon groups function very similarly to double carbon bonds, and, in particular, can often substitute for double carbon bonds for the purpose of shape, BUT they are much less reactive. This makes them a good alternative to double bond functional groups in, for example, drugs that work by docking to some target, where you don't want any side-chemistry that might disrupt the drug, but you also don't want to change the drug's shape. This bit of chemistry brought to you by... also Anders Knight!

June 04, 2016 at 01:55AM

Tody I Learned: 1) You can't pickle lambda functions in Python. Also, to use multiprocessing on a function, all of the arguments must be picklable. 2) Some (many?) refrigerators use a two-stage cooling system -- freon or another similar substance is cooled by expansion, then run alongside a secondary coolant (antifreeze is a good choice), which cools off and carries that coldness through the rest of the refrigerator. This fact brought to you via Andrey Shur and his recent explorations into the inner workings of a thermal cycler. 3) Many stepper motors (motors that have a large number of pre-defined positions they can snap to) have their own built-in microcontroller. These are operated by sending the microcontroller digital instructions, must like a number of plug-and-play devices. This fact also courtesy of Andrey Shur

June 03, 2016 at 12:19AM

Tody I Learned: 1) "Neural lace", also known as "Syringe-injectable electronics". It's a mesh-like metal device so thin and diaphanous that it can be injected with, you guessed it, a syringe. Right now they don't do a ton, but last year a Harvard team of scientists built a neural lace device for reading neural activity, injected it into mouse brains, and read out cell activity. The mice were completely unharmed as far as the researchers could tell, and continued to be unharmed by the presence of the lace for five weeks after injection (after which they were sacrificed for autopsy and histology). More interestingly, the mouse's brain cells incorporated the mesh, growing around it and forming tight junctions with it. 2) ...another terrifying way the Earth can kill you called a limnic eruption, or lake overturn. Limnic eruptions are very rare (fortunately), only occurring in large bodies of water that develop massive pockets of CO2 from geologic activity. A sufficiently large geologic disturbance can cause all the CO2 to erupt from the lake, displacing air in a huge radius and killing most everything in its path. Example: In 1986, Lake Nyos, in Camaroon, erupted. Scientists believe it probably created a 100-meter-tall fountain of water and foam, creating a tidal wave 25 meters high. Nobody's sure, though, because the massive cloud of CO2 killed pretty much everyone within 25 km of the lake, and knocked out everyone else. !!!!!! 3) On a *highly* related note, CO2 is about 50% denser than air, so large amounts of CO2 released at once will roll like fog.

June 01, 2016 at 11:25PM

Today I Learned: 1) In California, early-stage school building construction is exempt from environmental regulation if it is on existing school grounds and won't increase the school's population by more than 25% or 10 classrooms, whichever is smaller. 2) So there's this weird bit of notation in calculus where derivatives of functions of single variables are notated like df/dt, but partial derivatives of functions with more than one variable are written like ∂f/∂t. Why the different notation? The operator is the same, isn't it? I've now asked two people I trust to know basically everything important in math, and they have both told me they have little to no idea. The best answer I've gotten is that the ∂ is a signifier that there are other variables at play that are being held constant. To my programmer's mind, this is absolute nonsense. If you apply the "∂" operation to a function of one variable, it does *exactly the same thing* as applying the "d" operation, so why not call it the same thing? This is a weirdly non-informative TIL, but I thought it worth noting. 3) Dealing with cybercrime is a Hard Problem. Cybercriminals do the superhero thing where their real identities are secret, making them incredibly difficult to find and punish them. Moreover, cybercrime almost invariably crosses lots of national borders, which makes it really hard for any single nation's police force to track down a criminal. Crack down on drug dealers hacking passwords from a base in Russia, and they'll just up and move to China. Today I learned that the weakest link in many illegal criminal networks is the banks that process the criminals' activities. In 2010, researchers at UCSD put together a honeypot net of computers that harvested spam and followed every link they could find to try to figure out the economic topology of the organizations behind the spam. It turned out that something like 95% of all the illegal internet activity they found was running out of three banks. The next year, Microsoft went to Visa and asked them to "encourage" those banks to stop servicing the vendors that were responsible for pirated Microsoft products. This worked amazingly well, at least temporarily. Pirates have since moved on to other banks, but it still looks like banks are the weak point for cyber crime.

June 01, 2016 at 04:04AM

Today I Learned: 1) There are now a number of companies offering "robots as a service". In particular, there's something of a booming industry in renting robots to small farms. For example, one company (whose name I've lost track of) rents out drones that monitor growth and look for problems, like rust or irrigation problems. Another company rents out tiny drones about the size of a cat or dog that dart between rows of plants, depositing small amounts of fertilizer where it's needed. This model makes a lot of sense to me. We desperately need more efficient agriculture if we're going to keep using this planet (right now, we're using 40% of the arable land on the planet for farms. That leaves 60% for cities, residencies, industrial areas, and the wild). Robots are a good way to do that, but robots usually require a heavy initial investment and plenty of specialty to maintain. Companies offering robots as a service can absorb that upfront cost and specialize in maintenance, making the robots affordable to small farmers... and they make money while they're at it! 2) The human ear is a funny thing. Have you looked at an ear lately? Pretty weird-looking. It turns out that the shape of the ear distorts incoming sounds in a manner that depends on the direction from which the sound comes. The brain can identify the underlying sound, and based on the kind of distortion it detects, can figure out to some degree which direction the sound came from. Experimental evidence for this was published in a 1998 Nature Neuroscience paper by the title "Relearning sound localization with new ears". Scientists added a mold to subjects' ears to change their shape. The subjects immediately got worse at localizing sound, though they re-calibrated their hearing over the course of several weeks. 3) All references to the Great Barrier Reef, which has been doing quite poorly according to recent oceanographic surveys (as in, about a third of it is severaly bleached and/or dead), were removed from a recent Unesco report on tourism and climate change. Why? Because the Australian government asked them to, claiming that it might cause "confusion" and might hurt tourism. You know what else is bad for tourism? Losing your country's greatest natural treasure. Will politicians ever listen to the scientific community? I don't have high hopes.