Ciro Santilli @cirosantilli  40

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Undergraduate education Updated 2025-07-16

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University entry exam Updated 2025-07-16

These are the most evil examinations society has.

They mean that until you are 18, you have to study a bunch of generic crap you hate just to get into university. Rather than studying whatever it is that you truly love to become a God at it as fast as possible and have any chance of advancing the field.

And then, if you decide that you want to change, which is not unlikely since you haven't really try to study what you signed up for before then, it can be very hard and time consuming, leading to a bunch of adults with useless degress they will never use at work.

With the invention of the Internet, all teaching material can be free and open source. Only laboratory space has any cost (besides the opportunity cost of participation in actual projects in a research team).

Per-country list: en.wikipedia.org/wiki/List_of_admission_tests_to_colleges_and_universities

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Universities by country Updated 2025-07-16

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United States Department of Energy national laboratory Updated 2025-07-16

Where nuclear weapons and nuclear power, and a ton of derived research is made.

For a fun and brief random software encounter with that universe, see the VisIt section of stackoverflow.com/questions/5854515/interactive-large-plot-with-20-million-sample-points-and-gigabytes-of-data/55967461#55967461.

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Unicellular organism Updated 2025-07-16

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Multicellular organism Updated 2025-07-16

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Binary tree Updated 2025-07-16

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Ordered tree Updated 2025-07-16

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Tree traversal Updated 2025-07-16

The summary from www.geeksforgeeks.org/tree-traversals-inorder-preorder-and-postorder/ is a winner:

In principle one could talk about tree traversal of unordered trees as a number of possible traversals without a fixed order. But we won't consider that under this section, only deterministic ordered tree traversals.

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Scanning transmission electron microscopy Updated 2025-07-16

50,000,000x Magnification by AlphaPhoenix (2022)

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Electron holography Updated 2025-07-16

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Microphone Updated 2025-07-16

Testing and Circuit for a Condenser microphone by RSD Academy (2018)

Not very numerical, but shows a simple working breadboard circuit and an oscilloscope. He whistles with his mouth to get a pretty pure frequency.

That type of microphone requires a bias voltage. The circuit is in Ciro's ASCII art circuit diagram notation:

DC_9---R_10k--+--MICROPHONE--+--G
              |              |
              +-------V------+

Soundwaves on an oscilloscope by Animated Science (2015)

Source. Dude speaking to microphone. Some analysis of how different sounds look like. No circuit diagram.

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Loudspeaker Updated 2025-07-16

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Transcendental number conjecture Updated 2025-07-16

en.wikipedia.org/wiki/Transcendental_number#Conjectured_transcendental_numbers

There's a billion simple looking expressions which are not known to be transcendental numbers or not. It's cute simple to state but hard to prove at its best.

Open as of 2020:

$e + π$

Bibliography:

www.quantamagazine.org/recounting-the-history-of-maths-transcendental-numbers-20230627/ How Math Achieved Transcendence by David S. Richeson (2023).

Why π^π^π^π could be an integer by Stand-up Maths (2021)

Source. Sponsored by Jane Street. Shame.

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Semisynthesis Updated 2025-07-16

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Cell-free protein synthesis Updated 2025-07-16

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Cultured food Updated 2025-07-16

2024 www.uktech.news/foodtech/alternative-meat-research-centre-20240829
A research centre examining the implementation of alternatives to meat, backed by £38m, will be launched by the University of Leeds.
The virtual research centre will look into lab-grown meat as well as plant and fungus-based meat alternatives to determine the health, sustainability and feasibility of moving away from traditional meat.
2024 techcrunch.com/2024/08/04/even-after-1-6b-in-vc-money-the-lab-grown-meat-industry-is-facing-massive-issues/ "Even after $1.6B in VC money, the lab-grown meat industry is facing 'massive' issues"
www.reuters.com/markets/commodities/hoxton-farms-raises-22-million-cultivated-animal-fat-2022-10-20/ Hoxton Farms, cultured animal fat

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Histology Updated 2025-07-16

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Tinker Tailor Soldier Spy adaptation Updated 2025-07-16

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Boltzmann constant Updated 2025-07-16

This is not a truly "fundamental" constant of nature like say the speed of light or the Planck constant.

Rather, it is just a definition of our Kelvin temperature scale, linking average microscopic energy to our macroscopic temperature scale.

The way to think about that link is, at 1 Kelvin, each particle has average energy:

1/2 k T

per degree of freedom.

This is why the units of the Boltzmann constant are Joules per Kelvin.

For an ideal monatomic gas, say helium, there are 3 degrees of freedom. so each helium atom has average energy:

3/2 k_{B} T

If we have 2 atoms at 1 K, they will have average energy

6/2 k_{B} J

, and so on.

Another conclusion is that this defines temperature as being proportional to the total energy. E.g. if we had 1 helium atom at 2 K then we would have about

6/2 k_{B} J

9/2 k_{B} J

and so on.

This energy is of course just an average: some particles have more, and others less, following the Maxwell-Boltzmann distribution.

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