Ciro Santilli @cirosantilli 37

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Czochralski method Updated 2025-07-16

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Data Updated 2025-07-16

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Deep learning Updated 2025-07-16

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Deep learning is the name artificial neural networks basically converged to in the 2010s/2020s.

It is a bit of an unfortunate as it suggests something like "deep understanding" and even reminds one of AGI, which it almost certainly will not attain on its own. But at least it sounds good.

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DeepMind Lab Updated 2025-07-16

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github.com/deepmind/lab

github.com/deepmind/lab/tree/master/game_scripts/levels/contributed/dmlab30 has some good games with video demos on YouTube, though for some weird reason they are unlisted.

TODO get one of the games running. Instructions: github.com/deepmind/lab/blob/master/docs/users/build.md. This may helpgithub.com/deepmind/lab/issues/242: "Complete installation script for Ubuntu 20.04".

It is interesting how much overlap some of those have with Ciro's 2D reinforcement learning games

The games are 3D, but most of them are purely flat, and the 3D is just a waste of resources.

Video 1.

Human player test of DMLab-30 Collect Good Objects task by DeepMind (2018)

Source.

Video 2.

Human player test of DMLab-30 Exploit Deferred Effects task by DeepMind (2018)

Source.

Video 3.

Human player test of DMLab-30 Select Described Object task by DeepMind (2018)

Source. Some of their games involve language instructions from the use to determine the desired task, cool concept.

Video 4.

Human player test of DMLab-30 Fixed Large Map task by DeepMind (2018)

Source. They also have some maps with more natural environments.

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DeepMind project Updated 2025-07-16

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Deuterium Updated 2025-07-16

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Applications:

because it has an even number of nucleons it is transparent to NMR, and therefore is useful in solvents for NMR spectroscopy

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Dirac equation solution for the hydrogen atom Updated 2025-07-16

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Predicts fine structure.

Bibliography:

Video "Quantum Mechanics 12b - Dirac Equation II by ViaScience (2015)" youtu.be/tR6UebCvFqE?t=549

Video 1.

Dirac equation for the electron and hydrogen Hamiltonian by Barton Zwiebach (2019)

Source. Uses perturbation theory to get to the relativistic corrections of fine structure! Part of MIT 8.06 Quantum Physics III, Spring 2018 by Barton Zwiebach

Video 2.

How To Solve The Dirac Equation For The Hydrogen Atom | Relativistic Quantum Mechanics by Dietterich Labs (2018)

Source.

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Discounts that happen more often than not Updated 2025-07-16

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These are obviously just a manipulative lie sales practice to make you want to buy at regular price.

Shame on you.

Similarly, recurrent Internet payments that give you one year's discount, and make you put up on your calendar to call them one year later threatening to give more discounts to be as cheap as competitors or I'm out.

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Display manager Updated 2025-07-16

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Check which you you have:

systemctl status display-manager.service

Tested on Ubuntu 23.10 I see:

● gdm.service - GNOME Display Manager
     Loaded: loaded (/lib/systemd/system/gdm.service; static)
     Active: active (running) since Sun 2023-12-24 10:34:50 GMT; 23min ago
    Process: 1827 ExecStartPre=/usr/share/gdm/generate-config (code=exited, status=0/SUCCESS)
   Main PID: 1850 (gdm3)
      Tasks: 4 (limit: 71817)
     Memory: 6.8M
        CPU: 119ms
     CGroup: /system.slice/gdm.service
             └─1850 /usr/sbin/gdm3

which means I have GNOME Display Manager.

Bibliography:

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DNA detection Updated 2025-07-16

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DNA detection means determining if a specific DNA sequence is present in a sample.

This can be used to detect if a given species of microorganism is present in a sample, and is therefore a widely used diagnostics technique to see if someone is infected with a virus.

You could of course do full DNA Sequencing to see everything that is there, but since it is as a more generic procedure, sequencing is more expensive and slow.

The alternative is to use a DNA amplification technique.

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DNA microarray Updated 2025-07-16

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Can be seen as a cheap form of DNA sequencing that only test for a few hits. Some major applications:

gene expression profiling
single-nucleotide polymorphism: specificity is high enough to detect snips

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DNA repair Updated 2025-07-16

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DNS Census 2013 Updated 2025-07-16

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dnscensus2013.neocities.org/

Data format overview: opendata.stackexchange.com/questions/1951/dataset-of-domain-names/21077#21077

TODO was this data also obtained illegally like the Carna botnet

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Length contraction Updated 2025-07-16

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Suppose that a rod has is length

L

measured on a rest frame

S

(or maybe even better: two identical rulers were manufactured, and one is taken on a spaceship, a bit like the twin paradox).

Question: what is the length

L^{'}

than an observer in frame

S^{'}

moving relative to

S

as speed

v

observe the rod to be?

The key idea is that there are two events to consider in each frame, which we call 1 and 2:

the left end of the rod is an observation event at a given position at a given time: $x_{1}$ and $t_{1}$ for $S$ or $x_{1}^{'}$ and $t_{1}^{'}$ for $S^{'}$
the right end of the rod is an observation event at a given position at a given time : $x_{2}$ and $t_{2}$ for $S$ or $x_{2}^{'}$ and $t_{2}^{'}$ for $S^{'}$

Note that what you visually observe on a photograph is a different measurement to the more precise/easy to calculate two event measurement. On a photograph, it seems you might not even see the contraction in some cases as mentioned at en.wikipedia.org/wiki/Terrell_rotation

Measuring a length means to measure the

x_{2} - x_{1}

difference for a single point in time in your frame (

t 2 = t 1

So what we want to obtain is

x_{2}^{'} - x_{1}^{'}

for any given time

t^{'} 2 = t^{'} 1

In summary, we have:

L L^{'} = x_{2} = x_{2}^{'} - x_{1} - x_{1}^{'} t_{2}^{'} = t_{1}^{'}

(1)

By plugging those values into the Lorentz transformation, we can eliminate

t_{2} an d t_{1}

, and conclude that for any

t_{2}^{'} = t_{1}^{'}

, the length contraction relation holds:

L^{'} = \frac{L}{γ}

(2)

The key question that needs intuitive clarification then is: but how can this be symmetric? How can both observers see each other's rulers shrink?

And the key answer is: because to the second observer, the measurements made by the first observer are not simultaneous. Notably, the two measurement events are obviously spacelike-separated events by looking at the light cone, and therefore can be measured even in different orders by different observers.

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Interface Message Processor Updated 2025-07-16

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Les Atomes by Jean Perrin (1913) Updated 2025-07-16

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Subtle is the Lord by Abraham Pais (1982) mentions that this has a good summary of the atomic theory evidence that was present at the time, and which had become basically indisputable at or soon after that date.

On Wikimedia Commons since it is now public domain in most countries: commons.wikimedia.org/w/index.php?title=File:Perrin,_Jean_-_Les_Atomes,_F%C3%A9lix_Alcan,_1913.djvu

An English translation from 1916 by English chemist Dalziel Llewellyn Hammick on the Internet Archive, also on the public domain: archive.org/details/atoms00hammgoog

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Orange Papers Updated 2025-07-16

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See: cirosantilli.com/china-dictatorship/orange-papers

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Organ (anatomy) Updated 2025-07-16

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Organelle Updated 2025-07-16

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Organization developing photonic quantum computer Updated 2025-07-16

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