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Ask HN: Teach me something new

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Re: Ask HN: Teach me something new

#431

Post by leephillips »

exikyut wrote: post #188
leephillips wrote: post #101

By far the most important martial arts skill is the ability to function effectively after receiving a powerful blow to the face, solar plexus, etc. The only way to develop this skill is by practicing it; very few people do, for obvious reasons. If your martial arts training does not include this, it may have many benefits, but is severely lacking as training for actual fighting.

I guess the two questions that come to mind after I read this are 1. How can I OW objectively OW tell oww the difference ow where being seriously jarred (ow) ends and being significantly injured begins? 2. As a person ages, is it possible to train in this way without ending up seriously banged up with long-term ramifications? Or is this more of a "don't use a skateboard" type of thing with no leeway?

2.: I desisted after about age 45.

Re: Ask HN: Teach me something new

#432

Post by tomcam »

davidwihl wrote: post #359
scrollaway wrote: post #316

Take a few minutes to learn the NATO phonetic alphabet Alpha, Bravo, Charlie, Delta, Echo, Foxtrot, Golf, Hotel, India, Juliet, Kilo, Lima, Mike, November, Oscar, Papa, Quebec, Romeo, Sierra, Tango, Uniform, Victor, Whiskey, X-ray, Yankee, Zulu Gotta spell anything over a voice line? Use it. No more screwing around with "B.. like Bryan, and then U, like .... under". s-c-r-o-l-l-a-w-a-y: sierra charlie romeo oscar lim…

All pilots, private and commercial, have to learn this. I taught it to my kids driving to school when they were in elementary school.

I think it’s fantastic your kids were able to drive to elementary school

Re: Ask HN: Teach me something new

#434

Post by [deleted] »

Adrig wrote: post #260

You probably heard about the quirks in the French numerical system. For example, 99 is translated "quatre-vingt-dix-neuf" which is literally "four twenty ten nine". This is a legacy of the base 20 numerical system used by the Celtics thousands of years ago before the modern Romance language drove it out. The hybridization with our current base 10 system came with the Roman conquest of the Gaul. Another example of the…

[deleted]

Re: Ask HN: Teach me something new

#435

Post by ajb »

ZeroGravitas wrote: post #370
ajb wrote: post #229

In statistics, the mean and median are both averages, but are technically quite different. The mean is the sum of all items divided by the number of them, while the median is the middle item in the sorted list. When they are different, this can have strange effects. For example, when estimating engineering tasks, the mean error is often positive while the median is often negative. This is why your manager believes th…

One of the rules of thumb of process management is to reduce the median, rather than the average time taken, because outliers are more likely to have one-off causes and so be harder to fix systematically. In fact, attempts to fix outliers can be a distraction and even net negative.

Interesting. I wonder if that applies in SW dev though. In standard processes each correctly produced item satisfies a customer, but for sw dev individual tasks are internal and customers only care about the final outcome. Also standard processes normally involve Gaussian distributions, so large deviations are rare and can be called outliers, but software estimation has fat tailed or bimodal distributions, so large deviations are part of the standard order of business.

Re: Ask HN: Teach me something new

#436

Post by mmcconnell1618 »

amin wrote: post #2

Quantitative easing (sometimes mistaking called "money printing") isn't directly inflationary. Because when central banks buy bonds, they do not pay with normal money. Instead, they pay with a special type of money that can never enter the real economy (as to not create inflation). This special type of money are called "bank reserves". And bank reserves can only be used to 1) settle interbank transfers and 2) buy mor…

Doesn't the US have a fractional reserve banking system? For every $1 in bank reserves, the bank can loan out $9. So even if the special money of the Fed can't be used directly, it has the effect of allowing banks to have a larger base of reserves which means the banks can create money by loaning it out to others.

Re: Ask HN: Teach me something new

#437

Post by paulhalla »

tazjin wrote: post #363
schoen wrote: post #132

In the 1800s, scholars who knew a lot of languages (including, often, several modern and ancient European languages, and increasingly also Sanskrit) started to notice some amazing patterns about similarities in words among all of these languages, including languages from very far apart and that had no visible connection at all from the point of view of their present-day speakers. As these patterns were explored, they…

I've always found it interesting that some words are constructed the same across many languages. For example, response: responsibility in - English (well) - Russian (ответ : ответственность) - German (Antwort : Verantwortung) - Scandinavian (svar : ansvar) There's likely more! Even though the modern words have diverged completely, the concept behind the construct is the same.

Interesting! Same in Estonian (vastus: vastutus)

Re: Ask HN: Teach me something new

#438

Post by mjochim »

agumonkey wrote: post #340
schoen wrote: post #132

In the 1800s, scholars who knew a lot of languages (including, often, several modern and ancient European languages, and increasingly also Sanskrit) started to notice some amazing patterns about similarities in words among all of these languages, including languages from very far apart and that had no visible connection at all from the point of view of their present-day speakers. As these patterns were explored, they…

I laughed thinking about British empire teaching english to indians who they inherited most the language from. etymonline.com is a nice way to rabbithole time away with fun

> to rabbithole time away with fun

I absolutely love how you use rabbit hole as a verb here :D.

Re: Ask HN: Teach me something new

#439

Post by mfarstad »

ToJans wrote: post #110

I watched a piano/music teaching video from the 60s yesterday that made it all "click" [1] Most modern music chords patterns are easy to find out on piano. Start on any of the white keys, and play 7 white keys left to right. That is called a mode: a series of notes separated by certain intervals to compose a song. Different modes have different vibes. Atmosphere of the song ( sad or happy) is directly correlated by h…

Building off of this to talk about functional harmony (I recommend a book called modeology)

Look up roman numeral notation for this next bit.

A V-I is called a perfect cadence in the major scale, and pretty much any other mode in which those chords naturally occur. The most important tones are the major 7th, which is one semitone away from the root and has a strong desire to resolve up, and the perfect 5th, which is a very stable sound that wants to fall up a fourth or down a fifth to the root. As such, the third can be major, minor, omitted, or replaced and the function of the chord remains pretty much unchanged. This is called modal interchange, since we are borrowing from a different mode for the root, in this case any mode other than Ionian (major). Mode changes the strong and weak cadences, however, so be mindful your alteration doesn't make a progression fall apart.

My favorite is ii7, iio7, and Imaj7. Another topic thats fun is tritone substitution, but that would make this a borderline blog post.

o in this context is a diminished chord, which also means that 7 is double flat (bb) because theory.

It can get crazier, there's tons of YouTube videos that explain it better. But

Re: Ask HN: Teach me something new

#440

Post by mkl »

Beldin wrote: post #107

White dwarfs and neutron stars are both "stellar corpses", the remnant of stars. White dwarfs roughly cram the Sun's mass into an Earth-sized sphere, neutron stars cram that amount of mass into a sphere of about 10km diameter. Oh, and neutron stars have mountains: height differences on their crust of a few centimeters or less. Scaling that height difference takes more energy than scaling Mount Everest. Gravity is wei…

Robert L Forward wrote a fascinating novel about life on a neutron star: https://en.wikipedia.org/wiki/Dragon's_Egg
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