Archive for the ‘Worth Knowing’ category
I’d never really thought about it, but this is a nice little tour of some of the history of mathematic symbols.
Even our wonderful symbol for equality – you know, those two parallel lines – was not used in print before 1575, when the Welsh mathematician and physician Robert Recorde wrote an algebra book that he called the Whetstone of Witte. (We can only guess that the title is a pun on sharpening mathematical wit.) In it he wrote “is equal to” almost two hundred times for the first two hundred pages before finally declaring that he could easily “avoid the tedious repetition” of those three words by designing the symbol “=====” to represent them.
The reason I love a good book review is it gives 80% or the value of the book, plus some insight from (one hopes) an expert about how that book doesn’t quite achieve its potential. Thomas Piketty’s Capital in the Twenty-First Century is super hot this summer, and Larry Summer’s review does what I describe:
All of this is more than enough to justify the rapturous reception accorded Piketty in many quarters. But recall that Kennedy seemed to hit the zeitgeist perfectly but turned out later to have missed his mark as the Berlin Wall fell and the United States enjoyed an economic renaissance in the decade after he wrote; similarly, I have serious reservations about Piketty’s theorizing as a guide to understanding the evolution of American inequality. And, as even Piketty himself recognizes, his policy recommendations are unworldly—which could stand in the way of more feasible steps that could make a material difference for the middle class.
An interesting little tidbit: ants and the TCP protocol behave very similar. Natural engineering:
This feedback loop allows TCP to run congestion avoidance: If acks return at a slower rate than the data was sent out, that indicates that there is little bandwidth available, and the source throttles data transmission down accordingly. If acks return quickly, the source boosts its transmission speed. The process determines how much bandwidth is available and throttles data transmission accordingly.
It turns out that harvester ants (Pogonomyrmex barbatus) behave nearly the same way when searching for food. Gordon has found that the rate at which harvester ants – which forage for seeds as individuals – leave the nest to search for food corresponds to food availability.
Nothing I’d never heard and considered at least a little bit before, but this little piece about stories was a nice reminder.
The preponderance of narrative approaches lauded by the Pulitzer committee last week in the work of The Boston Globe, The Center for Public Integrity, and The Gazette, among others, demonstrates that our craving and connection to story is so much more than a haphazard preference.
Your brain on story is different than your brain when it is receiving any other form of information, including straight facts and data. There are proven intersections between neuroscience, biology, and story we cannot ignore. The threads of stories that we read, hear, watch, and click on affect us intrinsically. And tempt us as well.
It also reminded me of this old post where Tyler Cowen talks about stories making us dumber.
Outdoor races — especially ones that emphasize obstacles, toughness, and mud — have been a bit of trend in the US. And it’s also started to become a bit a public health issue:
Nowhere, though, does their pledge mention enduring infectious diarrhea. But it is a very real risk in this sort of event, the U.S. Centers for Disease Control and Prevention (CDC) now says.
In response to these three cases, Nellis Public Health mobilized local and state officials in an investigation, the results of which were released yesterday by the CDC. The team ultimately identified 22 similar cases tied to that October 2012 Mudder, most likely caused by infection with the fecally transmitted bacteriumCampylobacter coli.
As the CDC reported there was a statistically significant association with “inadvertent swallowing of muddy water while competing” and Campylobacter infection.
Because these races are usually built in farmers’ fields or other remote rural land containing feces, a lack of care from race organizers in assuring the cleanliness of their mud is understandable, but makes me even more hesitant to sign up for one.
I’m not really a coffee afficiando, but I’m close enough to white-upper-middle-class coffee culture to know that this device called an AeroPress is the way to make coffee. What I didn’t know, is that its inventor, Alan Alder, first made his business and living from flying discs.
My naive answer, as a bit of map-fan and not-completely-geographically-illiterate person was about 10. Turns out it’s more than that. I’ll say no more because I liked Jason Kottke’s reveal.
I don’t really understand the appeal of thorough-bred racing as a sport, but I found this to be an interesting fact:
Since 1949, the time it takes thoroughbreds to run around the 1.25-mile track has averaged 2:02.25, and no winning race time has deviated by more than 3 seconds from this long-term average.
There’s a few more interesting tidbits about the fastests speed that other animals (including people) can run in the rest of the piece.
Because no one likes to study cats, they’re jerks. As a dog person, that was my answer. Turns out, that’s actually the answer:
To reduce the number of variables, Agrillo’s team always conducts the studies in its laboratory. But when owners brought their cats over, most of the felines freaked out. Even the docile ones displayed little interest in the test. Ultimately, Agrillo wound up with just four cats—and even they were a pain to work with. “Very often, they didn’t participate in the experiment or they walked in the wrong direction,” he told me. “It was really difficult to have a good trial each day.”
People in pre-modern time had to drink wine and beer because their water was unsafe to drink.
I don’t know that this idea is as well established at this article suggests, but I’d definitely heard it and never doubted it very hard. But the point, being made, seems true to me:
There is no specific reason then to believe that people of the time drank proportionately less water than we do today; rather, since water was not typically sold, transported, taxed, etc., there simply would have been no reason to record its use. Did people in the time prefer alcoholic drinks? Probably, and for the same reason most people today drink liquids other than water: variety and flavor. A young man in a tenth century Saxon colloquy is asked what he drinks and answers: “Beer if I have it or water if I have no beer.” This is a clear expression of both being comfortable with water and preferring beer.