October 01, 2016 at 12:47AM

Today I Learned: 1) There is a style of restaurant called an automat which is essentially a giant vending machine, for food. They were apparently fairly common until the 70s? They died off primarily because a) fast food restaurants offered more flexibility and competed them into the ground, and b) inflation made it no longer feasible for customers to pay in coins, which is all most automats were set up to take (at least in the US). 2) Vacuuming robots can suck up a surprising amount of dirt. 3) CcdB is a gene coding an antibacterial. Today I learned how the ccdB protein works. It's an inhibitor of DNA gyrase, which is a protein that helps relax supercoils in DNA during replication. If all it did was inhibit DNA gyrase, that would be pretty bad, but it's actually much nastier -- the ccdB/gyrase complex can still function halfway, which involves snipping open one strand of the DNA helix and letting it unwind. It just can't stitch it back together, so ccdB turns DNA gyrase into a genome fragmentation machine.

September 30, 2016 at 02:38AM

Today I Learned: 1) ...about Valeria Lukyanova, colloquially known as "The Human Barbie". For a while, she dedicated a significant fraction of her life to immitating the physical appearance of a barbie doll. With her body. She did a pretty decent job, too -- through some combination of extreme dieting and possibly surgery (though she denies the surgery bit), she managed to get her proportions about right. She also applies a ridiculous amount of makeup for a pretty spectacular effect. I'm really torn about this case. On the one hand, as a general supporter of transhumanism, I applaud the use of the body for personal expression and the willingness to venture outside human body norms, even for purely aesthetic purpose. On the other hand... of the entire space of possible bodies, she went with *barbie*?!?! That's about the worst possible option I could have thought of. It's kind of pathetic, in my opinion. 2) Simple amplitude modulation (as in, signal encoding) is inefficient in terms of bandwidth. A naïve amplitude modulation scheme will use about twice the bandwidth of the baseband. There are, however, tricks you can use to cut this down. One, whose name I learned earlier today but have forgotten, makes use of symmetry in the Fourier transform of the signal -- since the Fourier of the signal is symmetric around some frequency, you can cut it down by only sending one half of the signal (in frequency space). 3) SSH communication can use public/private key pairs to authenticate a user. Instead of sending a host a password, you can essentially send them proof that it's you with a set of public and private keys you share with the server ahead of time. I don't actually know what the authentication algorithm is, but I imagine it goes something like this: the server sends you a secret, encrypted with the server's private key; you decrypt with the server's public key, ensuring that the secret came from the server; now you encrypt the secret again with your private key and send it back; the server decrypts with your public key, which you gave it in a previous transaction; if the decrypted secret matches the one it sent out, then it knows it's you and it knows you know it's it, and it begins a handshake protocol to open a secure connection. Today I learned that the above authentication is just that -- authentication. The public/private key pair is *not* used to encrypt any subsequent information -- that's all done the same way as in a password-authenticated session.

September 29, 2016 at 03:29AM

Today I Learned: 1) When shipping stuff on dry ice, you apparently need between 5 and 10 lbs of dry ice per day of shipping to keep it cold. 2) Agarose gels don't actually polymerize when they cool -- it's actually a gel of agarose, which is itself a long-chain polysaccharide. Agarose crystal is actually also a gel, sort of. It's a lot of chains cross-linked by hydrogen bonds, at least. Those cross-links stick around in solution, but heating an agarose solution breaks down the hydrogen cross-links, and cooling it down again lets them re-form... but this time, in a large, complete gel. For all the details (and a few details on how polyacrylamide gels work, which *are* polymerized), see http://ift.tt/2dmuaMN, courtesy of Anders Knight. 3) Webcams are considerably cheaper than I expected. You can get cheap USB ones on Amazon for about $20 without really looking hard.

September 28, 2016 at 03:32AM

Today I Learned: 1) ...how high-performance chromatography, like high-performance liquid chromatography (HPLC) and gas chromatography (GC) and other fancy methods like supercritical fluid chromatography (SFC). Here's what I knew: Chromatography is similar, in the most basic principles, to separating components of ink by spotting it on paper. A chromatography setup has a column with some kind of binding material (usually called the solid phase), over which you flow a sample (the liquid or gas phase) containing multiple compounds that you want to separate. Because different components in the liquid phase will bind more or less stongly to the solid phase, they move through the column less or more quickly, respectively. This causes them to come out the other end of the column at different times, so by catching what comes out at different times, you can collect different components. (You can also hook a chromatograph directly to a mass-spec to get really clean characterization of complex mixtures.) Here's what I learned: Chromatography is *not* like an electrophoretic gel, where you just flow a sample through and the more it binds, the longer it takes to come out the other end. Actually, whatever your chemicals-of-interest are are usually calibrated to bind really strongly to your column, at least initially! Your compound of interest, and possibly some other contaminants, will bind to the column, but lots of other stuff will wash through. The way you get the compound(s) of interest off the column is by slowly changing what kind of liquid you wash over the column (the buffer). As the buffer composition changes, it changes how well your compound sticks to the column, and at some critical point, your compound will flow off and you can collect it. For instance, nickel columns are used to collect His-tagged proteins*, because His tags stick to nickel pretty well. If you flow a mix of proteins with some his-tagged proteins (say, a cell lysate containing the tagged protein), then the his-tagged proteins will stick to the nickel column. Once all the excess proteins have washed through, you start to slowly add imidizole to the buffer on the column. His-tags are good at binding to nickel, but imidizole is *really* good at binding to nickel. As the imidizole concentration increases, it eventually starts to kick off the his-tagged proteins, and at some critical point, most of the his-tagged protein goes back into solution and flows off the column to be collected. Thanks to Anders Knight for a solid explanation of chromatography! * a His-tag is a bunch of histidine amino acids tacked onto the end of a protein, usually to make it easier to isolate. 2) The song "Barret's Privateers", which is a truly delightful, if somewhat depressing, classic sea shanty (might I recommend this recording by Stan Rogers? http://ift.tt/2dC1rUE) is actually a modern piece written by the selfsame Stan Rogers in the 70s. I would not have guessed that from listening. 3) Well, Elon Musk just released some new information on how he plans to get people to Mars (and beyond, if travellers are interested). I didn't read too much on the details, but basically it's a giant (*really* giant) two-stage reusable rocket. The rocket first takes a capsule containing crew and cargo to low Earth orbit and then falls back to Earth. It's hitched to a fuel container, launched *back* up into orbit to meet the capsule, and delivers the fuel that will get the capsule to Mars. Then the rocket falls back to Earth a second time to be refitted for another launch. The capsule jets away to Mars, using a solar sail for thrust in addition to the initial fuel consumption (and presumably a decelleration burn at the end? Can any Kerbal players fill me in on this bit?). The reusable rocket makes the trip relatively cheap -- Musk is estimating $500,000 per passenger for the initial flight, with costs potentially falling as low as $100,000 per passenger. The catch is that the initial capital investment required to build the rockets isn't trivial. Musk is estimating $10 billion, and he's not known for making conservative estimates. That's... really, really, *really* outside of SpaceX's price range. It would almost certainly require government money, in a sort of space-race-style project to get people to the moon. In that sense, Musk has just proposed a massive potential public project, rather than a company plan. Now, let's put that in perspective. That $10 billion will be spread out over many years. Musk's most optimistic guess is that we could have men on Mars in 2025. That's the *most optimistic* scenario, but it would spread the investment cost over something like 10 years. Really, though, I would guess that the capital investment will be pretty heavily front-loaded, and I'm also going to guess that it's going to take longer than 10 years, so let's say $2 billion a year for a while. That's about $6 per person per year (there are a lot of humans). How much is that, in terms of other things in our budget? In terms of science, a $2 billion a year is pretty big, but not overwhelmingly so. That's about half the budget of the National Science Foundation, which accounts for a huge fraction of scientific funding in the US. It's only a tenth or so of the budget of the NIH, though, and that's seen as worthwhile, so maybe the NIH could pivot massively and get us into space? But let's be real, science isn't the *first* thing to get cut when creating a new project. That honor belongs to education. The Department of Education received $77.4 billion from the federal government in 2012 (actually up a fair bit since 2010!), so we could get there with a ~3.5% cut to education for a decade, paying no more in taxes. Or, you know, we could cut military spending by a third of a percent.

September 27, 2016 at 03:14AM

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September 26, 2016 at 04:06AM

Today I Learned: 1) Most genes in yeast are kept at more or less constant levels of abundance throughout the cell cycle. Presumably the same is true for many other organisms? 2) How many Americans can play the piano? Google has no easy answers for this. The best I've found is a rather sketchy, badly-cited set of estimates from a Google Answers thread estimating between 1 million and 20 million (http://ift.tt/2cvFe5D). I *have* confirmed that about 12,000 grand pianos, about the same number of uprights and digitals, and about a million electric keyboards are sold each year in the US. Now those are some hard numbers to use to estimate total numbers of piano players, but it gives you some sense of the scale of piano usage in the US. 3) Wintermelon looks like a strange cross of honeydew and cantalope. It is not. Do not be fooled. It is actually a huge, fleshy, juicy melon that tastes roughly like the pith of watermelon, and is eaten more in soups and stir frys than on its on.

September 25, 2016 at 03:17AM

Today I Learned: 1) For a simple model of genome evolution, there is a critical mutation rate above which a species cannot maintain selective traits. The intuition is that it is much easier to mutate away from a specific genome than it is to mutate back to it, so if the overall mutation rate is high enough, it can overwhelm any selective advantage of the most-fit genome -- even if the most-fit genome has more offspring, too many will be less-fit mutants for that fitness advantage to matter. The transition is, at least for very sharply peaked fitness peaks, an abrupt phase-change. Below that mutation rate, the species will maintain a stable equilibrium of variants spread around the peak, centered on the peak. Above the threshold, adaptation more or less completely breaks down, and the species will explode in genetic diversity. The critical mutation rate threshold is, moreover, proportional to 1/N, where N is the genome length -- the larger the genome, the less mutation it can tolerate before becoming essentially unstable over multiple generations. I'd heard this idea before (that small genomes are in some sense more tolerant to mutations). Today I saw the math behind it. I won't go into it here, but suffice it to say that it's pretty simple, and pretty simplified. I also learned today that the critical mutation rate turns out to be close to 1 mutation per genome per generation, and it turns out that many species (dare I say most?) do fall under the regime of <1 mutation/genome/generation. Also, today I learned of an interesting side effect of the above stuff -- the mutation rate threshold is bigger for more broadly-distributed peaks in fitness space. That means that if there are two peaks in fitness space, with one very sharp and tall and the other less fit but broader, then a species with moderate mutation rate may actually gravitate to the broad, shorter peak instead of optimizing for global maximum fitness. I find that very satisfying, because it's a very formal way of thinking about "evolutionary robustness", which comes up fairly frequently in conversation about biology but is a little hard to justify intuitively. 2) Related to the above, think about how you would guess the following organisms rank in terms of mutation rate per genome *per generation*: human RNA viruses; bacteriophages; E. coli; yeast; fruit fly; mouse; human. Which do you think has the highest per-generation mutation rate? If you guessed "mouse", you're close -- estimates put mouse per-generation mutation rates at about 1/2 a mutation per genome per generation. But the highest rates in the above list belong to lytic RNA viruses. The table I'm reading from has per-generation mutation rates between 0.84 and 6.5, which is shocking above the critical mutation rate mentioned before. Which do you think has the lowest per-generation mutation rate? It's bacteriophages. Turns out that with the glaring exception of RNA viruses, the per-genome mutation rate is dominated by genomic size. Bacteriophages have relatively high per-base mutation rates (1,000-10,000 times higher than humans) but their tiny size means that their per-*genome* mutation rate is quite low (around 0.004/generation). 3) The shape of the clitoris (which, in case you don't know, is a much larger organ than it appears from the outside, and extends around much of the vagina) was discovered fairly recently. See this *1998* paper descibing the first modern dissection of the clitoris: http://ift.tt/2d0Bvzb. Here's the really obnoxious bit -- the shape of the clitoris *was* well known before the 20th century. Early versions of Grey's Anatomy included pretty accurate anatomical structures of the clitoris. Later versions, and virtually all other medical literature and textbooks, simply omitted them until fairly recently.

September 24, 2016 at 04:13AM

Today I Learned: 1) There are no common genotyping tests to determine suitibility of a cancer patient for radiation therapy. This is starkly different from chemotherapies, for which there are many genetic tests to predict safety and efficacy of the chemotherapy. It's not entirely clear why radiation therapy hasn't benefited from genetic testing the same way chemotherapy has, but it may simply be because radiation therapy scientsts tend to gravitate towards technological innovations for delivering radiation in more controlled, more precise, more measured ways. 2) We (meaning a bunch of scientists at Heidelberg) just discovered the molecular sensor that the human body (well, mouse body, but probably also the human body) uses to detect when a fever is high and when to shut it down. It's a temperature-sensitive ion channel called TRPM2 (Transient Receptor Potential Member 2). There are lots of other members of the TRP family, which are sensitive to different temperature ranges and are expressed in different places. TRPM2 is active in the preoptic area (POA) of the hypothalamus, which is a little bit of the brain responsible for tracking core body temperature and adjusting it in response to inflammatory signals. 3) iGEM will accept plasmids that aren't Biobrick compatible, though they won't count towards medal requirements.

September 23, 2016 at 03:39AM

Today I Learned: 1) ...that default ssh settings are really shockingly insecure. If I read those guides correctly, when you send your password when logging in, it sends it in plaintext! Key-pair login is much more secure -- that way you never have to send a password, and the server doesn't need to know a password (aside from the user's public key). 2) Fan death (the idea that running a fan in a closed room overnight can kill you) is, in fact, still believed in South Korea, though not as much among the young (if you believe an uncited sentence on Wiki). Moreover, Korean news agencies report cases of "fan death" relatively frequently (a couple of times each year). MOREOVER, the Korea Consumer Protection Board (a government-funded public agency) warns about fan death and states in no uncertain terms that direct use of a fan indoors can raise the risk of death by asphyxiation due to "[an] increase of carbon dioxide saturation concentration [sic] and decrease of oxygen concentration". 3) Speaking of ridiculous ideas, when Benjamin Franklin invented the lightning rod, Americans were hesitant to employ them. Why? Because lightning was believed to be primarily an act of God's righteous anger, and therefore carried a heck of a lot of heavenly power. Using a lightning rod to transfer that electric/dietical power to the ground would, obviously, supercharge the ground and make things like lightning more likely. I'm not making this up. http://ift.tt/2cq3JB0 The less on of the day is that a lot of things people know are complete and utter falsehoods. Use data. Experiment. Draw on the collective experience of the scientific community, at least when *it* uses data and experiments.

September 22, 2016 at 01:26AM

Today I Learned: 1) Korean has two ways of counting! It has one set of words for counting objects, as in "one tree, two trees, three trees", etc. It has another set of words for the mathematical objects of numbers, as in something you'd put on a number line. Interestingly, the latter set of numbers sounds *really suspiciously* close to Chinese words for those numbers. 2) Rounded to the nearest thing, I know nothing about the Aztec political system. Today, I read a bit about the Aztec political system, and with it, a bit about Aztec culture. My source is a blog post about a book by Inga Clendinnen, which can be found at http://ift.tt/2cnCszv. I still don't know *much* about Aztec culture or politics, but my new impression is that Aztec civic, political, and religious life was largely based around the production of intense, Carvinal-like communal experiences. If this particular soure is to be trusted (and is correct), the Aztecs were masters of using ritual for effect, and the kinds of religious rituals they underwent on a regular basis were addictive in their intensity and civically justified as critical for the continued function of the world without disaster (i.e., keeping the sun rising and the rain coming without flood). Really, though, I recommend reading the link above -- at this point, I'm giving at least a fifth-hand account. 3) Two Linux console tricks. 1) I finally learned how to access multiple command line prompts on a headless Linux system. 2) When using 'less', you can scroll sideways with the sideways arrow keys.

September 20, 2016 at 12:31AM

Today I Learned: 1) The Beatles were so ahead of their time that they quit performing live because their equipment couldn't handle the crowds. There didn't exist commercial speakers that could play reasonably well over the roar of the kinds of crowds the Beatles routinely generated. At some point, they decided that there was no point in playing live, because nobody could hear their music anyway. That was when they started devoting themselves full-time to studio recording. 2) ...proper application of a chop (the Asian style seal/signature). If you press it with a hard backing behind the paper, it doesn't apply very well (imperfections in the chop surface show up really strongly). A soft backing works much better, like a folded paper towel. 3) Very important cable management trick for serious cabling situations -- label both ends of the cable with a unique number, with a nice tape that won't come off or gunk up. That way you shouldn't ever have to go manually tracing a wire through a thick bundle of cables.

September 19, 2016 at 03:08AM

Today I Learned: 1) Hardy, of the Hardy-Weinberg equilibrium, was yet another example of a mathematician who was proud to never work on anything practically useful, but ended up being famous for deriving very practiacal, applied mathematics. 2) Single-population, two-allele evolutionary dynamics seem pretty simple at first blush. If the populations are big enough that genetic drift isn't a problem, then the one with the higher fitness grows in the population until the other one doesn't. Today I learned that that's only true if population growth is exponential, i.e. the rate of reproduction of each population is exactly proportional to the size of that population. If the rate of growth is *slower* than exponential, then there is a stable equilibrium between the two populations where both can coexist. If the rate of growth is *faster* than exponential, then fitness is actually more or less irrelevant -- there is an unstable nonzero equilibrium between the two species, and whichever species starts with a larger population than it has at that equilibrium will dominate regardless of the relative fitness of the two populations. When would you encounter sub- or super-exponential growth in a population? A nonreproducing population with immigration would be an example of subexponential growth -- there, population growth is entirely determined by a (potentially) constant immigration. A mix of reproduction and immigration also can result in subexponential population growth. An example would the release of sterile insect populations into the wild, which is done to bring down wild pest populations. Superexponential growth happens any time two organisms have to find each other to mate, as in sexually reproducing species -- the denser the population, the more likely it is that each individual reproduces, and the faster overall population growth. 3) I read a claim today that the terms transcription and translation (as in, transcription of RNA from DNA and translation of RNA into protein) were coined by John von Neumann, to refer to processes in an abstract self-replicating automata schema he had theorized. There wasn't a citation given, but context clues suggest that the term was, as I say, coined in "Theory of Self-Reproducing Automata", a classic 1966 work on, well, self-reproducing automata* **. Well, I read through a chapter (chapter 4: http://ift.tt/2cJdGxl) of that book looking for references to transcription and translation before realizing that I was just reading a chapter excerpted from a bit of a longer work than I wanted to read in one Sunday afternoon. In any case, I didn't see any reference to transcription and translation exactly, though it *did* contain a theoretical description of abstract machinery surprisingly like the transcriptional machinery of the cell... not surprising, since it was inspired by the same (although it was written before most of the details of either transcription or translation had been worked out, so there are some telling differences among the similarities). I eventually found a text version of the book (link available here, along with a bunch of other formats: http://ift.tt/2d9SVt4) and ctrl+f'ed for "transcrip" and "transl", and there was nothing quite resembling transcription and translation in the biological sense. Phoey. Would've been a great story. In any case, von Neumann is great. Go check out his works. The chapter linked above has, among other things, a really nice succinct little comparison of brains, computers, and theoretical thermodynamic limits. If you're interested in computation, this is a must-read. * Ever heard of a von Neumann machine? This is the book that defined it. ** I'm not sure if von Neumann actually penned anything in that book. It's "edited and completed" by Arthur W. Burks. What I read of it reads as a sort of "best of" compilation of von Neumann's best lectures, interspersed with some commentary and summarization by Burks.

September 17, 2016 at 04:41AM

Today I Learned: 1) Two transcriptional elongation factors called GreA and Greb are very, very important for efficient transcription in E.-coli-based* transcriptional systems. Addition of GreA and GreB to a minimal in vitro transcription/translation system (PURE express) increased yield about 6-fold, which brings them much, much closer to the kinds of yields we regularly get out of TX-TL. * anyone have a better way to punctuate this? 2) When you assign a computer a new IP address, you may need to release and refresh that computer's IP configuration, which can be done by running ipconfig \release ipconfig \refresh 3) ...a bit about how stocks and public companies work. As I gather, the basic idea of stocks is that it's a way for a company to make a ton of money by selling itself to lots of shareholders who want to invest in a company without shelling out tons of money or getting directly involved with the company in any kind of deep way. When a company "goes public" (which basically means it signs up on some kind of public trading list and legally commits to making a bunch of its financial information public), it gains the ability to sell stocks to whoever wants to buy them. This is great for the company, because it gives them a huge influx of instant cash. It's even better for early investors, because they typically get paid back during the going-public event. Stocks nominally derive their value either from dividends that the stock pays (which are typically single-digit-per-year returns) or from the ability of a stock-owner to vote in certain decisions of the company with a weight proportional to the number of stocks the stock owner owns. In practice, I'm fairly confident that stocks are more like currency than a good -- they have value because everyone believes they have value. Companies can decide to create and sell more stock whenever they want to. When that happens, it can be really bad for investors who already own stock, because a) they suddenly own far less of the controlling share of the company and b) the supply of stock goes up drastically (which I suspect is the bigger effect). However, it can also be really good for investors, because selling stock gives the company a ton of money to work with, which can put them way ahead in the marketplace, which can make their stocks more valuable again. So it's an intricate balance. Another thing companies can do is *split* their stocks, which means they basically declare that everyone who owns stock now owns, say, twice as many stocks with half the value each (or, in general, X times as many stocks with 1/X times the value each). This is apparently really annoying for stockholders, although I don't really know why, but it's nice for the company because it lowers the barrier to purchase a single stock. Google once promised that they would never split their stocks, but they did when their stock reached something like $1000/stock. Warren Buffet also once promised that he would never split his stocks for Berkshire Hathaway, and he has held true to his word -- as of tonight, those stocks go for $218,400 apiece. Thanks to Kevin Cherry for graciously imparting some of his knowledge of stocks and stock trading!

September 16, 2016 at 02:00AM

Today I Learned: 1) A couple of DARPA projects currently listed on their wiki page: bullets designed to penetrate armor by melting and being formed into a spike by a powerful electromagnetic field; wearable jetpacks to increase infantry speed; a mind-controlled robotic arm; a headset that reads and transmits your thoughts in order to communicate covertly; SyNPSE (Systems of Neuromorphic Adaptive Plastic Scalable Electronics -- any idea what that is?); and multiple independent powered exoskeleton projects. 2) There is a small but awesome subculture of DIY drivers who make and drive mono-wheel bikes. I'm not talking about motorcycles with one wheel (though those exist too, apparently!), I'm talking about one giant wheel that you sit inside, like the thing General Greivous rides. It's actually two concentric wheels. The inner wheel spins relative to the outer one, and the weight of the motor pushes the assembly forward. There are some serious desgin problems with the mono-wheel bike. The most egregious is probably the braking system. Traditional braking systems don't really work, so you have to brake with your feet. On the road. You'll want to wear some tough boots if you try that. They also require some work to balance, especially since you usually have to bend out sideways to see around the wheel. The owner* of one particularly beautiful mono-wheel bike described the experience of riding it as "more like flying than anything else" -- the seat kind of floats around the inside of the outer wheel, so you don't feel particularly grounded. * extremely charming man, at least on video. He seemed the happiest man in the world on that thing. "It never fails to put a smile on people's faces", he said repeatedly. 3) Spices are *even cheaper than I thought* from the Mexican section of a typical supermarket. I've always known they were cheap, but... well, today I bought some coriander seeds from the Mexican section. A little baggie was about 1/8 the cost of a shaker full of coriander seeds, although the baggie was smaller. ...or so I thought! Turns out the baggies just *look* smaller -- the contents of one baggie fit almost exactly into a (used) coriander seed shaker, so really they're just 1/8 the price.

September 15, 2016 at 02:31AM

Today I Learned: 1) Gough Island, a South Pacific island known for being the sole breeding site of the Tristan albatross, has a surprising invasive species -- the house mouse. Mice were introduced to the island by ships *relatively* recently, though I don't know whether that's a few decades ago or a few hundred years ago. The mice have no predators on the island... and the albatross has absolutely no defenses against them. That's right, defenses. Against the house mouse. See, Gouhg Island mice have evolved to be much bigger than normal house mice, and have switched from an herbivorous diet to a diet of albatross chicks. The albatrosses are much, much bigger than the mice, but predatory mice can squeak in, nip off a little bit of flesh, and leave before the chick can do anything about it. Over the course of a night, a swarm of mice will nibble the bird to death. This is a serious problem for the albatrosses of the island, and has set their numbers in decline. Time will tell whether they can evolve a defense quickly enough to survive. 2) You can break a zip tie with a shoestring. Citation: http://ift.tt/2d0PeJ1 Ripped from Kitty Mayor's facebook post a couple hours ago. 3) ...about an art project called Forms in Nature*. It's basically a really, really beautiful series of ceiling light covers shaped like a mad, zero-G circulatory system, designed to cast shadows that make the room look like a dimly-lit forest. The pieces are each unique and algorithm-designed, then custom 3D-printed out of a nicely heat-resistant plastic and hand-assembled. Every one of the forms is a an exclusive experience... and they're priced accordingly, at something like $3,500/piece. You know what, though? That description really doesn't do it justice. Just go check out their webpage: formsinnature.dk *though to be honest, it's almost certainly not the only art project with that name....

September 14, 2016 at 01:54AM

Today I Learned: 1) Our autoclave will, in fact, open if it isn't finished with its cycle. Wasn't even that bad -- I didn't notice anything was wrong until I'd already taken out a bottle. 2) Metal prints are the most beautiful way to get an art print. Also one of the most expensive ways. Sadly, computer screens do not give this point justice -- you're going to have to find some yourself to really see what I mean. 3) Speaking of amazingly beautiful things, check out the red beach, in Panjin, China. It's a huge marsh dominated by a brilliant red species of alkaline-tolerant reed. It is also the site of one of the largest (wiki claims *the* largest) wetland preserves in the world.

September 13, 2016 at 02:43AM

Today I Learned: 1) Ever heard of a Nash Equilibrium? Informally, it says that in any game (economist-speak for an interaction between two or more parties where different outcomes have different values) satisfying certain conditions, there is a stable set of strategies that the players could arrive to for which no player would gain by switching strategies. There is no guarantee that the equilibrium is *good* for all, or even any, of the players, nor that the players will actually arrive at that equilibrium (even if they play perfectly rationally), but an equilibrium definitely exists. Today I learned a semi-formal set of conditions under which the Nash Equilibrium Theorem holds. It holds with a game of any finite number of perfectly rational players, where each player has a finite set of "pure strategies" that can be mixed probabilistically (i.e., a voter on a committee might vote for proposition A, proposition B, or proposition A with 10% probability and proposition B with 90% probability, or any other combination of probabilities). And... that's about it. The choice of strategies can, as far as I understand, be arbitrarily complex, as long as the decision ends up being some probabilistic combination of pure strategies. That's a shockingly powerful theorem, if you ask me. Thanks to George Artavanis for presenting about, among other things, Nash Equilibria. 2) John Wilkins, the 18th century natural philosopher, tried to write a universal language capable of communicating any thought in a clear fashion. I'd read a little bit about this scheme in Neil Stephenson's "Quicksilver", but today I learned a few more details about it. The universal language was motivated as a replacement lingua franca for latin -- something traders and diplomats could speak in any language. It was to be developed roughly in two parts -- a "real character" set and a "philosophical language". The real characters were to be a system for generating written characters that could representing any idea, in an abstract, non-verbal way (kind of like the way chinese writing acts as a non-verbal medium for speakers of different dialects). The philosophical language was, in some sense, a mapping from the real characters to spoken word. In general, the philosophic language was structured so that each additional character in a word would narrow down the meaning of the word, in some systematic way -- for example, "be" might be the word for machines, "ben" might be the word for electronic machines, "beni" might be the word for computers, "benit" might be the word for desktop computers, and so forth. The universal language was met with great excitement when it was first announced, but as you can probably guess, it never really went anywhere. 3) It turns out that there *is* a rule describing how adjectives are arranged in English! Ever noticed how you can have a big red ball, but a red big ball sounds strange? I've been wondering what rules define what order adjectives come in for a while now, and while it seemed that there were some generalizations about things like color coming after size, I never found a complete set of rules. It turns out there is one! It's not even that complicated! According to one Mark Forsyth (not the W&M one), The rule is that adjectives must come in the order "opinion-size-age-shape-color-origin-material-purpose noun". A complete example he gives is a lovely old rectangular green French silver whittling knife. Now, the question is, how the heck do we all learn this rule without ever actually learning *about* it? Thanks to Mengsha Gong for finally bringing me some peace on this subject!

September 12, 2016 at 04:55AM

Today I Learned: 1) A thymister is an electronic component kind of like a transistor, except that the output is either on or off -- instead of amplifying current like a transistor, a thymister acts as a switch. 2) It has been observed since the 60s that the children of holocaust survivors are more prone to PTSD, and suffer more severe PTSD, than the rest of the population. This has been confirmed over and over again, but there's no solid known mechanism. Recently, there's been a fair amount of somewhat fringe science on transgenerational epigenetic changes in response to stress, which has been hypothesized as one explanation. Jury's still out, as far as I'm concerned. 3) ...how to install a window AC! It's really pretty easy, although a little more difficult if you have a vertical window....

September 10, 2016 at 02:35AM

Today I Learned: 1) Here's an interesting little fact concerning the politics and game theory of global warming, as pointed out by George Artavanis. Although the usual proposed mechanism for stopping or slowing global warming is to cut greenhouse gas emissions, there are other, technologically feasible ways to stop global warming and potentially even reverse it. Fueling blooms of oceanic plankton is one way. Another would be to release or seed large amounts of sulfur gas into the atmosphere to generate cloud cover. Those techniques are fairly likely to work, and they're actually pretty cheap to implement -- the only problem is that we don't know what kind of side effects they could have, and pushing back too hard on global warming could potentially be just as catastrophic as making it happen in the first place. So, pretend you are the head of government of some small island nation. Perhaps an island nation that is literally going to sink into the ocean if global warming proceeds. The other nations of the world aren't doing what it's going to take to stop global warming. Suddenly, it sure looks like it's in your best interests to seed the atmosphere and start cooling down the planet! If you get a mini ice age for your trouble? Not a problem! That will only really affect Europe and North America. And so, here is one additional little incentive for the big countries to come up with a good solution to global warming -- if they don't, some little country is going to deploy a really, really bad one. 2) Also from George Artavanis, a game theoretic term called "salami tactics". Salami tactics are a method of undermining threats of sanctions (or nastier things, like nuclear war) by "slicing" out little pieces at a time. You start by violating some agreement just a tiiiiny bit -- enough that you get something, but small enough that nobody is willing to engage in costly sanctions to punish you. Then you escalate just a little bit more. Then just a little bit more. At every step, it's really, really hard for the other side to justify hurting themselves a lot just to punish you. The name comes from the way you're slicing away bits of your agreement, like slicing off pieces of salami. I really can't get over that name. 3) There is at least one library of yeast clones with GFP tags of every gene. Each clone has GFP attached to one protein-coding gene, so if you want to know how much of some gene is expressed under some condition, you just pick out the right clone, grow it up, put it in the condition you're interested in, and see how much it glows. This fact brought to you by Andy Halleran.

September 09, 2016 at 12:57AM

Today I Learned: 1) A radio galaxy is a galaxy that emits a lot of light from synchrotron radiation. Synchrotron radiation is light emitted by electrons that are accellerated radially through a magnetic field. I'm not entirely clear on what causes synhrotron radiation in galaxies, but certain galaxies make a lot of it. Radio galaxies get their name because synchrotron radiation is primarily radio-frequency, although it does extend up through and past the visible range of the spectrum as well. 2) Back in 2006, NASA launched a radio telescope called ARCADE to the edge of space using a balloon. There are plenty of radio telescopes on the ground, but they work by comparing one pixel of the sky against another nearby pixel, and look for contrast. Among other things, ARCADE was sensitive enough, or otherwise had the right equipment, to measure absolute radio intensity. What ARCADE discovered is the Space Roar -- all of space appears to be lit up with about six times the radio noise that anybody had expected. We still do not know where the Space Roar comes from. 3) Tor, which stands for "The Onion Router", is a system of anonymous information routing via the internet. It is so named because it makes use of onion routing, which is a technique for preserving anonymity where a message has multiple layers of encryption, like an onion, that are sequentially decrypted by successive network nodes. Because of the method of encryption, each node can only decrypt its layer, which means it only knows where it received the packet from and where it should send the packet, but not anything further upstream or downstream, making it very difficult to trace where packets come from or go to. Surprisingly, at least to me, onion routing was developed *and patented* by the US Naval Research Laboratory. A couple of researchers at the NRL developed Tor and arranged for it to be released with a free license, and later split off to found The Tor Project, a non-profit organization that now manages and develops Tor.

September 07, 2016 at 11:54PM

Today I Learned: 1) A dead tree, caught on another dead tree, creaking while blowing around in the wind, sounds surprisingly like a bleating elk, or perhaps a young bear. 2) Sweetened aloe juice (which tastes like fruity sugar water) is considerably better than raw aloe juice (which tastes like battery acid). The little aloe chunks that come in it are also quite tasty. Relatedly, Lychee juice tastes just like lychee jelly cups. Thanks to Sarah Seid for finding these things to try! 3) Bitcoin miners aren't searching for new bitcoins, or at least that's not their primary function in the bitcoin economy -- they are actually public ledger-writers, which store publically-available transaction records involving bitcoins ("blocks") in a heavily-distributed network of such transactions ("block chains"). Transactions are verified by consensus of the miners. Miners are rewarded for creating blocks with a small number of bitcoins. Creating a block is intentionally computationally intensive to keep the supply of bitcoins relatively stable. I also learned how to make something like writing a block computationally intensive. Bitcoin miners are required to include a "proof of work" in any block they publish. A simplified explanation of the proof of work is that it's a modification to the block which makes it hash to a small value using RSA or another hash (i.e., it hashes to something starting with a bunch of 0s). This is computationally intensive -- the only known way to find such modificaitons is to try variations until one works. Verifying that the work has been done is quite easy, though -- you just apply the modification, hash the modified block, and see if it starts with enough 0s.

September 07, 2016 at 11:53PM

Yesterday I Learned: 1) ...how to play a dulcimer, at least in the broadest possible outlines. Dulcimers have four strings -- a tonic string (brass-wrapped), a string a fifth above it, and a pair of strings each an octive above the tonic (two strings so that the volumes match). The simplest/standard way to play is to hold down chords on the frets and strum out chords, but you can also leave the bottom two open as a drone and just move around on the top two notes as melody. Thanks to Sarah Seid for teaching me! 2) There is such a thing as vegan sour cream, and it can actually be used to make a passable vegan tzatziki, but it really seems closer to heavily-whipped cream cheese in consistency and flavor. I haven't tried it on toasted bagel yet, but I really want to. 3) ...the tastes of pure citric acid, tartaric acid, and malic acid in water. Malic acid tastes like the tartness in an un-ripe blackberry. Tartaric acid tastes like the sourness in some grapes, and a bit like limes. Citric acid... is sour. You've all tasted it -- it's all over candies and drinks of all kinds and a surprising number of other foods. Thanks again to Travis Blount-Elliott

September 07, 2016 at 11:53PM

Two Days Ago I Learned: 1) Paddlefish. Go Google Image search them. Now, some basic background. Paddlefish are considered something of a "living fossil" -- they've been around for a very long time (late Cretaceous) with very few morphological changes, and they're still around, though struggling a bit. Up until recently, there were two known species, the American Paddlefish and the Chinese Paddlefish. The Chinese species hasn't been seen in the wild for over a decade, and is thought to be extinct. The American Paddlefish is "Vulnerable" -- it's not endangered yet, but it's likely to become endangered soon. I don't know much about why Paddlefish have been doing so poorly lately, but I'd guess it has a lot to do with their size and slow reproductive cycle. They're BIG FISH, which makes them really fun targets for fishermen, and they only bear young every couple of years, not starting until they're something like seven years old. It's pretty sad that we're killing off a family that's been around since the dinosaurs. 2) In a double-blind, randomized taste test of seven different vegan milk alternatives by two people, Trader Joes' original rice milk was the clear winner, oat was clearly the worst, and walnut chocolate milk was really quite good. 3) Meads and beers can be back-sweetened (that is, additional sweetness added after fermentation) with sugar or honey, but you have to add something to stop yeast growth first or it will start to ferment again. Potassium sorbate and potassium metabisulfite are good yeast-inhibitors for this purpose. Credit to Travis Blount-Elliott, who as far as I can tell is a meading wizard.

September 04, 2016 at 08:42PM

Today I Learned: 1) JIF cashew butter is actually pretty tasty. It tastes a lot like the Trader Joes' organic, non-homogenized cashew butter tastes when the Trader Joes' version is optimally mixed. 2) ...what a gar looks like. I do not, as of yet, understand why they have mouths like they have. 3) There's a species of turtle in Virginia called a chicken turtle which is remarkable, as far as I can tell, mostly because it has an extremely long neck -- sometimes it can stretch its head out a full body-length.

September 04, 2016 at 08:42PM

Yesterday I Learned: 1) When fishing, you typically want to pick a lure that matches the food that's around in the environment (same color, size, visual texture, etc). That way, the fish will already be on the lookout for that kind of lure and will be more likely to bite it. 2) One of the leading precussionists in the world is virtually deaf*. She plays a variety of precussive instruments, largely things like triangles and xylophones and glockenspiel, and listens to them largely through visual cues (you can see deeper instruments vibrate) and sympathetic vibrations in the body (mostly bones like finger bones, skull, etc). She started going deaf when she was quite young, and worked with her music teacher to listen to her instruments with body parts other than the ear. * sorry, I did not learn her name. 3) Pennywort juice is... really interesting. For one thing, it's turbid. Not opaque, not transparent, not full of visible chunks, but turbid -- there's some kind of invisibly-small particulate matter suspended (not quite permanently) in pennyworth juice that makes it murky. The flavor is... complex. It hits you with a bunch of different flavors, from sweet juiciness to bitter tea-like notes to a really grassy flavor like the scent of cut grass. I like it, but it's definitely not for everyone.

September 02, 2016 at 11:32PM

Today I Learned: 1) When children start to speak, they do so by making vowel sounds. After a while of making vowel sounds, they start practicing consonants. They'll spend some time practicing both of these, alternating in spurts of vowel practice and consonant practice. 2) When children start to *sing*, they almost all have about the same vocal range, and the vast majority can carry a tune accurately (though some children can only carry a tune if they hear another child singing). The first problems in vocal music development happen when adults start directing song. Adults, you see, rarely sing in the same range as children -- mostly they sing lower, unsurprisingly. So when an adult leads a bunch of children in song, they usually do so in a way that makes it hard for the children to follow. Children generally will respond in one of two ways. Some will transpose the song into a key in their vocal range. Others will try to sing with the adult, in the adult's key, and generally fail. Either way sounds wrong to adults. This is the moment when children typically hear "you can't sing" or "just mouth the words". It's not because the kids can't sing, it's because the adults don't know how to sing like children. 3) Balkan music sounds... kind of strange to most westerners. This is because to a listener raised in the Balkan tradition, the most harmonious interval is a second interval, not a third (a second interval is two notes right next to each other in a scale -- play any two white notes next to each other on a piano with a black note between them to hear a second. A third is two notes each separated by a second -- play any two white keys next to each other on a piano with *two* black keys between them to hear a third). Now, I really like the Balkan sound, but I'm in the odd position of enjoying Balkan music through the filter of western classical harmonic traditions, so I honestly don't know what that music sounds like to a native singer. 4) Music literacy in the US peaked around 1910. At that time, virtually every middle-class American could read sheet music, and essentially every American at least knew someone (usually in the family) who could read sheet music and, usually, play piano. Sheet music was a big industry during this time, kind of like CDs in the 90s or MP3 downloads and streaming services today. 5) Americans in the 19th century sang quite a bit. Song, usually accompanied by piano, was a very popular form of parlor entertainment (and huge numbers of pianos were imported from Europe to fuel the demand for parlor music). Americans also continued to sing straight through puberty, so they learned to sing in child-like registers. As a result, 19th Century Americans sang *really* high to our modern ears. 6) General William Sherman, the general who arguably ended the Civil War by razing a huge swath of Georgia to the ground, was a proponent of slavery, but a stronger defender of national unity. 7) Turkish music (and I think Macedonian music too?) has a few tricks I haven't encountered before. For example, the Turkish musical tradition uses a lot of rythems of 9. That in itself isn't *so* bad, but they also have a habit of stuff like starting the melody on the *second* beat of the nine. That really thows me off. 8) Learned a bit about life on Scottish farms at the beginning of the 20th century. For one thing, I learned that a "town" at that time was not what we would call a "town". A Scottish "town" was essentially a farmer's property -- a big house, a barn, a silo, and a bunch of land for crops and animals. The land-owning farmer was essentially the lord of the town, and his wife the lady. I'm not sure exactly what they did, but they didn't do everything -- most of the labor was done by hired hands. Every year, at the beginning of the season, there would be a big hiring fair where all the local farmers would try to recruit workers for the season to do all kinds of things. The workers would sign on for a six month gig, during which they worked long, hard days (10 hour days were advertised as competitive) every day in exchange for room and board and payment at the end of the six months (somewhere around 6 lbs for a young teen work hand, upwards of 25 lbs for a horseman). 9) Those aforementioned farming workmen ate the same meal every day, three times a day, and I got to try some of that meal. It's an oat gruel, somewhere between plain grits and oatmeal in consistency and flavor. A couple of tablespoons of that stuff would swell up in hot water to make a small bowl's worth, and it was surprisingly filling (though not terribly nutritious). Typically, this stuff was eaten with a ton of salt, and was cooled by dipping a spoon-full at a time in milk before eating it. The workers would use one bowl, which they didn't bother to wash -- as long as milk didn't get in the bowl, that worked just fine. It was fairly tasty, if plain. But then, if you're eating the same meal about 540 times in a row, you probably want that meal to be something pretty plain. 10) Scottish horsemen were the highest-ranked farm hands short of the farmer and his wife. They were quite proud of their role, and, as I noted before, were paid accordingly. I'm not sure why the ability to mind a horse was so highly valued, but there you have it. The horsemen also had a semi-secret fraternity involving a secret word which was supposed to give them power over horses and women. This reputation may have had something to do with their social and economic rank -- farmers knew about this Word, and they *did not* want horsemen to set their horses against them or steal their women (young women were valuable workers as well as reproductive assets). When a young horseman was deemed ready by his (always his) fellows, they would tell him to meet them at some specified time and place in the night. They would blindfold him, strip him to the waist (practically scandalous at the time) and bring him to see "Old Nick" (and old common name for the devil), who was one of their own dressed up in a pig hide. They'd have him shake hands with Old Nick, using a cow's foot to shake with to deepen the illusion. They would then make him take a vow not to ever use the Word except to horses in service of their work, etc., and once he agreed, they'd tell him the word. Then they'd take off the blindfold, show him what was up, and have a good laugh and a drink. Finally, just before leaving for the night, one of the brothers would ask for the newly-inducted member to repeat back the word, which he almost always did... in violation of his just-taken oath. A waiting horseman with a whip would then give him a lash on his still-exposed back, just to remind him the importance of keeping his oath. 11) There's a small genre of Scottish songs called "waulking songs", which have nothing to do with walking and probably weren't called that by the people who sung them, but some ethnomusicologist called them "waulking songs" while collecting them and that name has somehow stuck. Waulking songs were used during the final stage of creating a new cloth blanket or cloak or other large item. This came after all the spinning, weaving, and dying. One of the final steps was to soak the cloth in urine and then dry it out. This both set the dye so it wouldn't wash right out in the first rainstorm and also shrunk the cloth somewhat, making it less porous. The urine-soaked cloth needed to be dried, and worked by hand so that it dried evenly. To do this, the cloth would be sewn or tied into a loop and laid around the edge of a table. A bunch of women (or, in a few parts of the country, men) would gather around and work the cloth dry. Working a large loop of cloth evenly turns out to be pretty challenging, even with ten or twenty people working in parallel. A good way to keep it evenly-worked is to pass it around regularly. Well, that introduces a new challenge -- how do you spin around a large loop of cloth every few seconds, continuously, for a half hour or so? This is where waulking songs came in. Waulking songs, like sea shanties, have a regular rythem with a frequent strong beat that would signal the women to pass the cloth. By singing these songs, they kept the work synchronized. It also kept them entertained, which is important to do when you're consistently working 10 or 12 or 14 hours a day of hard labor. 12) There was an Italian regiment in World War II that specialized in spying on Americans. They learned to speak flawless American English and would kind of just waltz behind enemy lines and pretend to be Americans. This was, by one account, pretty successful.f 13) You can sing pretty much any songs together as long as they're in the same keys at the same times. Turns out a LOT of old American songs use the same chord progressions, so it's not hard to sing five or ten different old American tunes together at once without sounding too bad. 14) There was a big shift in American popular music in the late 1800s driven by massive amounts of immigration from Germany and the surrounding areas (a product of a series of German revolutions). The influx of Germans brought with it a big shift in musical sensibilities. Before this, most American parlor music was essentially Irish or Scottish, modified for American tastes. Germans brought with them Romantic sensibilities -- much more complex harmonies, and a greatly increased emphasis on dying or dead young women. Slightly relatedly, guess where Blues came from? It turns out that early blues was basically ragtime music slowed waaay down. Obviously it has evolved since then. 15) Fire trucks cost order-of-magnitude around $1 million. 16) Some of the most popular American singers of the early 20th century were black women. Blues were quite popular in the early 20th century, as were travelling vaudeville troupes. There were several very famous black women who travelled with those troupes, singing blues. It was acceptable for both black and white audiences to listen to these performers, and as long as they stuck to double entendre and implication, it was a way for otherwise genteel folk to listen to some raunchy music. Incidentally (though not so incidentally to the women involved, I'm sure) it was considered standard practice for traveling singers to prostitute themselves to make a little extra cash. 17) The speed of sound in water is determined by its density, which in turn is affected by salinity, temperature, and pressure. A combination of a bunch of effects makes the density profile (and, thus, the speed-of-sound profile) of open-ocean water somewhat complex. Near the surface, there are a bunch of effects (evaporation, surface waves, sunlight and photosynthesis, mixing with air, etc) that make the density profile really messy. At large depths, density is dominated by pressure, which linearly increases with depth. Between these two regimes is a region with a U-shaped density profile -- the density decreases for a while, I think largely because differences in salinity due to evaporation, before starting to rise again as you get down to the linear regime. One consequence of the U-shaped density profile is that there's a depth band that acts like a mirror gallery for sound -- sound produced at certain depths will bounce around at that depth. This means it doesn't dissipate into the upper and lower layers, which in turn means that it propagates *very* far*. If you drop a microphone down into that band, you will hear everything in a very, very large radius. This is useful for sonagraphic ocean research... and it's also really important for submarines, because a submarine in that band is extremely conspicuous to anyone listening. * It's basically a fiber optic line, but for sound instead of light, and in a plane instead of a line. 18) A timing attack is not, as I'd previously assumed, some sort of DDoS-like attack. It's actually a method of hacking a password by exploiting one of the time-saving feaures of equality comparison in standard code. The point of a timing attack is to figure out a password by repeatedly trying different passwords and using information about how *long* it takes for each access request to come back. This can work because of the way equality of things like strings are usually calculated. A standard string equality algorithm starts by checking the first letter (or byte) of the two strings. If they're equal, then it moves on to check the next letter (or byte). If they're not equal, the algorithm returns "false" and, in the case of a password-checking algorithm, the access request is denied. The key point here is that a password which is correct in the first 127 characters but wrong on the last character will take *longer* to check than a password which is wrong in the first character. How do you take advantage of this? It's simple. Try a bunch of passwords of approximately the right length with every possible first character. Repeat a few thousand times. Record the average time-to-rejection of each password. You should see that one of the passwords consistently takes a few tens of microseconds longer to process than the others. That password is the one with a correct first character. Now repeat the process, using the correct first character and varying the *second* character. Repeat for every character. Password cracked. I'm frankly surprised that this works -- I would think that such a small singal would be drowned out by all the noise in processing time and, especially, signal transmission time. Apparently, though, you can detect small enough differences just by collecting enough timing examples. 19) Bcrypt is a cryptographic hashing algorithm* based on Blowfish. Blowfish is cryptographic hash involving a lot of blocking and xoring and modulo addition and frankly I don't have a clue how it works. The key point is that it's very efficient, pretty fast, and gives a strong hash. The only real weakness of blowfish, to my knowledge, is that it can be broken given enough (computing power x time) by just trying all the possible passwords until you find the one that hashes to the right value. This is a general weakness of all hashing algorithms... ...except Bcrypt! Sort of. Bcrypt is based on blowfish, but it goes through multiple rounds of blowfish-like hashing, with a variable number of rounds that you can set manually. The major advantage of this scheme is that if you're concerned about someone brute-forcing the attack, you can simply increase the number of rounds of encryption, and the attack will take longer! This simple feature makes bcrypt *scalably* secure. * For those who don't know what a cryptographic hashing algorithm is, here's an introduction to modern cryptography: A common problem in cryptography is the problem of checking a password. Say you're a bank, and you want to know whether someone trying to log into their bank account is actually them. The simplest thing you could do is to have the user send you a password, and have a database of everybody's correct passwords, and when the user sends you what they think is the password, you check it against what you have stored and see if they're equal. This is really insecure for a couple of reasons: 1) If someone intercepts the packet(s) with the password, they now know the password; 2) If someone hacks into your system and gains access to your database, they have *everybody's* password; 3) *You* know the user's password, which could be undesirable. I'm not going to talk about how to fix issue 1, but 2 and 3 can be fixed with proper cryptographic hashing. A cryptographic hash is an algorithm that takes a password (say, "adminpass0") and does something to convert it into a number in a deterministic way that's really, really hard to reverse. Usually this involves multiplying by really large prime numbers and taking mods and stuff like that. In any case, a cryptographic hash typically produces a hex string (say, "5810fe0a0b53bc80") called a "hash"**. Again, the key property of a hash is that it's relatively easy to turn a password into a hash, but really, really difficult to go the other way around (it's basically the difference between multiplying together two large numbers and trying to find the prime factors of the result). Now, instead of storing the user's password, you store the *hash* of the user's password. The user now sends you the password (still not securely at this point! Again, I'm not going to touch on that particular problem). You hash the password on your end and check whether it has the hash you stored. If it does, then you let the user in! If it doesn't, then they must have had the wrong password, and you let the request bounce. This way, you can tell whether the user supplied the right password without ever having to store the value of that password. ** I guess the idea behind the "hash" metaphor is that you start with an intact thing, like a potato, which gets irreversably turned into a muddled-up thing, like a hash brown. Never thought about that before. 20) Learned a couple of musical French games. I'm not going to try to describe them in detail here -- suffice it to say there was hand-slapping, broomstick contortions, musical improvisation, and a lot of singing. 21) Tartan weave probably was invented so that skeins of cloth of different colors could be easily used together in the same cloth.