D-Day exhibit at Bletchley Park
Rose Design did some really lovely work for the design of the 75th anniversary of D-Day exhibit at Bletchley Park. The D itself was made from ticker tape; they used the ITA2 Boudot-Murray teletype standard to type the words “Interception Intelligence Invasion” (interspersed with NULs to make it more aesthetically pleasing):
I had hoped they’d encrypted the words with the Lorenz SZ-40 cipher, used by German High Command, which Colossus was created to break. But ITA2 is certainly much cooler than A=1, B=2, etc.
Sonorous rocks
http://www.geologyin.com/2019/07/ringing-rocks-geological-and-musical.html
A more plausible theory is that the elastic stresses remained in the rock when the boulder fields formed, and the slow weathering rate keeps the stresses from dissipating. A possible source of the stresses would likely be the loading stresses from the time when the rock crystallized. The diabase sill formed at roughly 1.2–1.9 miles (2–3 km) beneath the surface.
This “relict stress” theory implies that the ringing rock boulders act much like a guitar string. When a guitar string is limp it does not resonate, but a plucked string will provide a range of sounds depending on the level of applied tension.
Obligatory:
Using EEG and TMS for low-bandwidth telepathy
EEG on people staring at flashing lights can pick up difference between different frequencies. TMS can create phosphenes. These guys hooked them together and played Tetris.
https://www.sciencealert.com/brain-to-brain-mind-connection-lets-three-people-share-thoughts
At least three different times, crocodiles evolved to become herbivores
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Borneo earless monitors look the most like fantasy dragons
Followed closely by the armadillo girdled lizard:
Text generators
In the last year, enormous progress has been made in generating coherent text.
https://minimaxir.com/apps/gpt2-small/ A model less than a tenth the size of the 1.5B GPT2 model that the researchers are refusing to release. Dreamlike, choppy, somewhat incoherent, but an order of magnitude better than what we had last year.
https://grover.allenai.org/ – type in a headline, then hit “generate” on the body box. Grover was designed to distinguish fake news from real news, so it knows how to avoid the problems that plague gpt2-small. This stuff is just barely distinguishable from human authorship.
Analysis says there are four different kinds of sepsis that need to be treated differently
Using a combination of statistical, machine learning, and simulation tools, the researchers combed through data relating to 20,000 past hospital patients who had developed sepsis within six hours of admission.
In particular, they looked for clusters of symptoms and patterns of organ dysfunction, then correlated them against biomarkers and mortality.
The findings revealed not one discernible type of sepsis, but four, which the researchers label alpha, beta, gamma and delta.
Alpha sepsis was the most common, affecting 33% of patients, and carried the lowest fatality rate, about 2%. At the other end of the scale, delta sepsis occurred in only 13% of patients, but had an in-hospital death rate of 32%.
To further test their discovery, Seymour and colleagues ran the same analysis on records for a further 43,000 patients, all of whom had been treated for sepsis between 2012 and 2014. The finding held.
https://cosmosmagazine.com/biology/sepsis-treatments-wrong-by-definition-study-finds
Pluto may have subsurface ocean insulated by clathrates
Popular account: “And if Pluto has such materials, it stands to reason that other outer solar system bodies also have them, including not only the moons of Jupiter and Saturn, but possibly other large Kuiper Belt objects, even farther out from the sun than Pluto.”
https://cosmosmagazine.com/space/pluto-has-an-insulated-underground-ocean
Nature article:
https://www.nature.com/articles/nature20148
Latest claim: Voynich manuscript was written in proto-Romance
https://www.tandfonline.com/doi/full/10.1080/02639904.2019.1599566
Edit: Aaand now it’s been withdrawn.
Each one had six wings; with twain he covered his face, and with twain he covered his feet, and with twain he did fly.
All insects have two pairs of wings, sprouting from the second and third segment of the thorax. Even insects that appear to have only one pair, like flies and beetles, really have two: in flies, the second pair of wings diminished to new structures called halteres, while in beetles, the first pair became the elytra. In cockroaches and bugs, the first pair only got halfway to elytra and are called hemelytra.
But! A 2011 paper in Nature gives morphological and genetic evidence that the helmet of treehoppers is derived from a third pair of wing buds on the first segment. Hox genes have suppressed wing expression on every segment but 2 and 3 for 300 million years. Hox genes control repetition of certain body parts. They are very strongly preserved, since they govern the gross body plan of a creature—in humans, for instance, they control how many vertebrae we have. The authors suspected that the treehopper hox gene no longer suppressed production on the first gene and inserted it into drosophila flies to see if wing primordia formed, but they didn’t. So somehow, despite the hox genes being preserved, treehoppers found a way around the inhibition of wing production and were able to evolve their fantastic helmets.
TIL: Till is not a shortening of until
‘Til is a corruption of till under the assumption that it is a shortening of until, but till is, in fact, an older word than until. Both till and until mean the same thing.
Journey to the black hole at the center of the galaxy
Here’s some context for the recent black hole image.
Shock diamonds and aerospikes
I was curious what caused the oscillations in rocket exhaust. I learned they’re called “shock diamonds”, among other names, and are due to the lateral pressure of the exhaust being mismatched with the atmospheric pressure. At low altitudes / high pressure, the exhaust is immediately pinched and then bounces off itself as the pressure increases, then becomes repinched as it expands again. At high altitudes / low pressure, the exhaust expands first, then gets pinched at the lower pressure. The bell-style rocket only has its maximum efficiency at one specific altitude; this is one reason for multistage rockets.
There’s a rocket design called an aerospike that effectively uses air for half the bell and then controls the flow to match the air pressure. It’s more efficient, but has had bad luck as far as deployment goes. Since fuel is about the cheapest part of a rocket, new space companies have opted for using known, proven designs instead. This is a good video about the history and development of the aerospike.
While looking for the explanation, I came across this wonderful paper that examines what happens when two laminar flows collide. Depending on the viscosity, surface tension, and velocity of the streams, you get several different “phases” of interaction.
A modest proposal for overloading arithmetic operators in JavaScript
Bignum usage:
var x, y;
with(BN) {
y = L5;
x = BN()(L282376418273964982736149872 * L29618763948127639 - y);
}
console.log('' + x);
// 8.363640477374324661331988841549874089512203e42
Complex usage:
console.log(Complex()({r:2, i:0} / {r:1, i:1} + {r:-3, i:2}))
// {r:-2, i:1}
Note that JavaScript does not support overloading operators in the same way as C++, but here they work fine. Note also that it would be easy to write something like eval(translateToJS(myDSLstring)), but here I’m using raw JavaScript arithmetic operators on objects, something that usually just gets you concatenations of “NaN” and “[object Object]”.
The setup for operator overloading enumerates all expressions involving the binary operations +, -, *, / with up to five variables indexed from left to right. It calls Math.random() five times and stores the results in a list R. It substitutes the nth random number for the nth variable in the expressions, then stores the expression under the result in a table. Real numbers chosen uniformly at random in [0,1) are transcendental with probability 1 and therefore satisfy no algebraic equation; while we don’t have transcendentals, the number of bits in an IEEE 754 double easily suffices to distinguish the set of expressions we want to handle.
BN is a Proxy object with a get handler that returns, for any property beginning with ‘L’, a Bignum object from your favorite bignum library encoding the rest of the property name as its value. BN temporarily replaces Bignum.prototype.valueOf so that it pushes “this” onto a list V and returns the corresponding random number at the same index from the list R. The function BN() looks up the appropriate expression in the table, gets the actual values from V and returns the evaluation of the expression with the variables bound to the values, emptying the list V and replacing the original valueOf before returning.
Complex() replaces the Object.prototype.valueOf with one that does the right thing with an object like {r:-5, i:-3}. It’s also straightforward to implement automatic differentiation in a similar way.
We don’t necessarily need to stick to mere objects; we can even do things like monadic bind by replacing Function.prototype.valueOf.
Current developers are sadly undereducated in the fantastic tools that JavaScript provides for enriching the lives of future developers tasked with maintaining their code. I encourage everyone to make broader use of them.
Source
The interesting code starts at line 956.
Start at line 1044 to see how to define your own overloadings.
The “valueOf pushes objects into a list” trick for operator overloading came from Brian McKenna’s Bilby functional library, but it only allowed a single kind of operator in an expression: when applied to two functions, >= returns true, > returns 0, * returns NaN, and + returns a string (the concatenation of their sourcecode). I came up with the “enumerate expressions and store them under the result of evaluating them on transcendental numbers” trick to allow multiple operators and the “proxy handler to parse the identifier and construct an object” trick.
Lightfield 3d photos from an inkjet!
Lumii uses multilayer Moire patterns to simulate lightfields. You print out the layers on a regular transparency from an inkjet printer!
Fantastic fossil find from dinosaur killer asteroid
Seismic waves from the Chicxulub impact set up enormous standing waves in a large inland sea in North Dakota. The waves hit the mouth of an incoming river, which focused the waves into a 30 foot wall of water that knocked down trees and put fish next to triceratops and hadrosaurs in the fossil bed. The fish’s gills were also clogged with tektites, ejecta from the impact made of hot glass spherules that set the world’s forests on fire.
https://news.berkeley.edu/2019/03/29/66-million-year-old-deathbed-linked-to-dinosaur-killing-meteor/?T=AU
JavaScript can’t be fixed
In 2015, Andreas Rossberg of the V8 team proposed making JavaScript a little saner by making classes, objects, and functions unalterable after their construction so that a sound type system becomes possible.
A year later, his team reported on their progress and said that there’s basically no way to do that without breaking compatibility with everything that came before.
Any sound type system that’s compatible with old code will have to admit that JavaScript “functions” really aren’t and will have to model a lot more of JavaScript’s insanity.
A whale-eating whale
The Basilosaurus is not, as its name suggests, a lizard, but a prehistoric cetacean, a mammal. It grew up to 60 feet long (18 m). It could bite with a force of 3,600 pounds per square inch (25,000 kPa), chewing and then swallowing its food.
Bob Pepper’s Dragonmaster Cards
I got these cards for my birthday one year in the early 80s. We didn’t play the game very much—it was too hard for me as a little kid, and I was the oldest of my siblings—but I was always impressed by the art work and would pull them out just to look at them
New Zealand batflies
South American batflies are parasitic on their bats, but the ones in New Zealand are vegetarian coprophages, eating the pre-digested fruit in the bats’ guano.
https://www.nzgeo.com/stories/batfly/
New cervical cancer test has 100% accuracy
“A new test for cervical cancer was found to detect all of the cancers in a randomised clinical screening trial of 15,744 women, outperforming both the current Pap smear and human papillomavirus (HPV) test at a reduced cost, according to a study led by Queen Mary University of London.”
Happy Quantum Day!
On this day in 1900, Max Planck presented his theory of blackbody radiation to the German Physical Society (Deutsche Physikalische Gesellschaft, DPG).
https://en.wikipedia.org/wiki/Max_Planck#Black-body_radiation
Sometime during December of 1925, Schrödinger came up with the wave equation of a nonrelativistic electron; he wrote about it in a letter to Wien on 1925-12-27. So we could say that Quantum day has a half-life on the order of 10 days!
A recording of Mark Twain (sort of)
Not a recording of Twain, but a recording of a professional imitator who lived next to Twain for years.
Scarab beetles and circularly polarized light
a) left-polarized b) unpolarized c) right-polarized
https://www.sciencedirect.com/science/article/pii/S0040609013020592
http://www.mmpolarimetry.com/beetles-reflecting-left-circularly-polarized-light/
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