Superfluidity Updated +Created
Video 1.
Alfred Leitner - Liquid Helium II the Superfluid by Alfred Leitner (1963)
Source. Original source: www.alfredleitner.com.
Video 2.
Ben Miller experiments with superfluid helium by BBC (2011)
Source. Just quickly shows the superfluid helium climbing out o the cup, no detailed setup. With professor Robert Taylor from the University of Oxford.
Alex Honnold Updated +Created
Arbitrary waveform generator Updated +Created
Cancer Updated +Created
Control theory Updated +Created
This basically adds one more ingredient to partial differential equations: a function that we can select.
And then the question becomes: if this function has such and such limitation, can we make the solution of the differential equation have such and such property?
It's quite fun from a mathematics point of view!
Control theory also takes into consideration possible discretization of the domain, which allows using numerical methods to solve partial differential equations, as well as digital, rather than analogue control methods.
Diode Updated +Created
Ideally can be thought of as a one-way ticket gate that only lets electrons go in one direction with zero resistance! Real devices do have imperfections however, so there is some resistance.
First they were made out of vacuum tubes, but later semiconductor diodes were invented and became much more widespread.
Dirac delta function Updated +Created
The "0-width" pulse distribution that integrates to a step.
There's not way to describe it as a classical function, making it the most important example of a distribution.
Applications:
Kilian Jornet Burgada Updated +Created
Micronation Updated +Created
Video 1.
How do you start a new country? by Jay Foreman (2021)
Source.
Normal distribution Updated +Created
Partial differential equation Updated +Created
TED (conference) Updated +Created
A bit like a cult.
Many speakers are good. But especially in TEDx, we've had some notorious ones:
Bitcoin investor Updated +Created
Video 1.
What Happened When Bitcoin Made People Rich Quickly? by Vice News (2022)
Source. Meh, too long and not many cool things.
Circuit board Updated +Created
Current source Updated +Created
Digital and analog electronics Updated +Created
Electronic switch Updated +Created
Electronics YouTube channel Updated +Created
Exam Updated +Created
Exams as a prerequisite for a degree are useless. Exams as part of a degree must be abolished. And degrees must be abolished. Ultimately the only metrics that really matter are money and fame. See also: motivation.
The only thing exams should matter for is as a screening tool to select people with specific abilities that you care about as an employer or principal investigator. If:
  • you have no idea about what the content of specific exams are (and you don't because they are all ad-hoc university secrets)
  • or don't have a way to machine learn what grades correlate with your desired performance (you don't because where's the data?)
then exams are useless for your purposes. then might as well just go by interviews (basically what all employers do already, though not PIs). Degrees are too course grained to mean anything to anybody. Employers and PIs likely only care about very few specific subjects.
Once the question of an exam has been formulated, the usefulness of the problem is already been completely destroyed, because formulating the problem that matters is the most important part of things. And any problem with an answer, is useless to put effort into: give answers.
Furthermore, preventing people from searching for answers while answering an exam, AKA preventing "cheating", also makes absolutely no sense. In the real world, we want people to find answers as quickly as possible! We should be teaching people how to "cheat"! What we should teach them instead is what a fucking license is, and what you have to do to comply with it.
And if you pass the exam, you pass the course, without any further time requirements.
And those exams must be applied by professional test application companies to ensure no cheating and to factor out the anti-cheat work, while still making the tests available to people anywhere.
A quote from Richard Feynman present in the book Surely You're Joking, Mr. Feynman chapter O Americano, Outra Vez!:
You cannot get educated by this self-propagating system in which people study to pass exams, and teach others to pass exams, but nobody knows anything.
You learn something by doing it yourself, by asking questions, by thinking, and by experimenting.
The only metric that matters is "to feel that you've satisfied youre curiosity". When one studies for that, it can take a lot more time to actually learn everything, because it is sometimes not as clear when you should stop. But it is the only way to go deeper.
A person's understanding is the most illiquid asset that exists, to judge that based only on standardized exams, is a certain way to fail to identify top talent.

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