The first Bitcoin exchange. Coded as a hack, and they didn't manage to fix the hacks as the site evolved in a major way, which led to massive hacks.
Their creation is clearly visible on the archive history of bitcoin.org: web.archive.org/web/20100701000000*/bitcoin.org which started having massively more archives since Mt. Gox opened.
If you are a programmer,
grep becomes a verb: "to grep" means "to search text files", much like "to Google" means "to search random stuff online".
Section type:
sh_type == SHT_STRTAB.Common name: "section header string table".
The section name
.shstrtab is reserved. The standard says:This section holds section names.
This section gets pointed to by the
e_shstrnd field of the ELF header itself.String indexes of this section are are pointed to by the
sh_name field of section headers, which denote strings.This section does not have outputs:
SHF_ALLOC marked, so it will not appear on the executing program.readelf -x .shstrtab hello_world.oHex dump of section '.shstrtab':
0x00000000 002e6461 7461002e 74657874 002e7368 ..data..text..sh
0x00000010 73747274 6162002e 73796d74 6162002e strtab..symtab..
0x00000020 73747274 6162002e 72656c61 2e746578 strtab..rela.tex
0x00000030 7400 t.The data in this section has a fixed format: www.sco.com/developers/gabi/2003-12-17/ch4.strtab.html
If we look at the names of other sections, we see that they all contain numbers, e.g. the
.text section is number 7.Then each string ends when the first NUL character is found, e.g. character
12 is \0 just after .text\0.The 3D regular convex polyhedrons are super famous, have the name: Platonic solid, and have been known since antiquity. In particular, there are only 5 of them.
The counts per dimension are:
Table 1.
Number of regular polytopes per dimension
. | Dimension | Count |
|---|---|
| 2 | Infinite |
| 3 | 5 |
| 4 | 6 |
| >4 | 3 |
The cool thing is that the 3 that exist in 5+ dimensions are all of one of the three families:Then, the 2 3D missing ones have 4D analogues and the sixth one in 4D does not have a 3D analogue: the 24-cell. Yes, this is the kind of irregular stuff Ciro Santilli lives for.
How the hell are you supposed to develop an open source implementation of something that has a closed standard?
Not to mention open source test suites, that would be way too much to ask for, those always end up being made by some shady small companies that go bankrupt from time to time, see e.g. .
Basically the opposite of security through obscurity, though slightly more focused on cryptography.
For a commented initial example, see: e. Coli K-12 MG1655 gene thrA.
KEGG does the visual maps well.
But BioCyc is generally better otherwise.
High level simulation only, no way to get from DNA to worm! :-) Includes:
- nervous system
- muscle system
3D body viewer at: browser.openworm.org/ TODO can you click on a cell to get its name?
OpenWorm Sibernetic demo by Mike Vella (2013)
Source. Sibernetic adds a fluid dynamics solver for brain-in-the-loop simulation of C. elegans.The by far dominating DNA sequencing company of the late 2000's and 2010's due to having the smallest cost per base pair.
To understand how Illumina's technology works basically, watch this video: Video 1. "Illumina Sequencing by Synthesis by Illumina (2016)".
The key innovation of this method is the Bridge amplification step, which produces a large amount of identical DNA strands.
The hard part then is how to make any predictions from it:
- 2024 www.nature.com/articles/d41586-024-02935-z Fly-brain connectome helps to make predictions about neural activity. Summary of "Connectome-constrained networks predict neural activity across the fly visual system" by J. K. Lappalainen et. al.
2024: www.nature.com/articles/d41586-024-03190-y Largest brain map ever reveals fruit fly's neurons in exquisite detail
As of 2022, it had been almost fully decoded by post mortem connectome extraction with microtome!!! 135k neurons.
- 2021 www.nytimes.com/2021/10/26/science/drosophila-fly-brain-connectome.html Why Scientists Have Spent Years Mapping This Creature’s Brain by New York Times
That article mentions the humongous paper elifesciences.org/articles/66039 elifesciences.org/articles/66039 "A connectome of the Drosophila central complex reveals network motifs suitable for flexible navigation and context-dependent action selection" by a group from Janelia Research Campus. THe paper is so large that it makes eLife hang.
Stack overflow allows deleting content/making it visible only to 10k rep users.
Ciro Santilli is strictly against this, and this is an intended core policy of OurBigBook.com.
If you delete people's content randomly, they will be much less likely to write anything.
Getting downvoted to oblivion is one thing, but data loss? Unacceptable.
Only illegal content must ever be deleted. Or extremely obvious spam. But anything in a gray area should never be removed.
Deletion can be done by either:
- votes of high reputation users
- moderators
- or worse of all, which happens often on the smaller websites: auto-deletion because come content has not received enough views/votes above some treshold! stackoverflow.com/help/auto-deleted-questions. The most illogical thing of all is that the question is not even permanently removed from the system, only hidden from other/low reputation users! So it does not save any disk space at all! Mind blowing!
The most practical/precise volt standard.
It motivated the definition of the ampere in the 2019 redefinition of the SI base units
The wiki page en.wikipedia.org/wiki/Josephson_voltage_standard contains amazing schematics of the device, apparently made by the US Government.
Schematic of a typical Josephson voltage standard chip
. Source. 
The evolution of voltage metrology to the latest generation of JVSs by Alain Rüfenacht
. Source. Talk given in 2023. The speaker is from NIST, and the talk was hosted by the BIPM. Fantastic talk.- youtu.be/VoRab8U2eS0?t=354 the desired output voltage is 10V
- youtu.be/VoRab8U2eS0?t=475 lists the three most commonly used 10V implementations currently:
Technical aspects of realizing the DC volt in the laboratory with a JVS by Stéphane Solve
. Source. Talk given in 2023. The speaker is from BIPM, and the talk was hosted by the BIPM. Fantastic talk.- youtu.be/6pgGNJby1lw?t=296 gives the experimental setup used to compare two different references. Notably it involves a nanovoltmeter
This makes it clear how the Lie bracket can be seen as a "measure of non-commutativity"
Because the Lie bracket has to be a bilinear map, all we need to do to specify it uniquely is to specify how it acts on every pair of some basis of the Lie algebra.
Then, together with the Baker-Campbell-Hausdorff formula and the Lie group-Lie algebra correspondence, this forms an exceptionally compact description of a Lie group.
This section is about the definition of the dot product over , which extends the definition of the dot product over .
Some motivation is discussed at: math.stackexchange.com/questions/2459814/what-is-the-dot-product-of-complex-vectors/4300169#4300169
The complex dot product is defined as:
E.g. in :
Just like the usual dot product, this will be a positive definite symmetric bilinear form by definition.
In the context of Maxwell's equations, it is vector field that is one of the inputs of the equation.
Section "Maxwell's equations with pointlike particles" asks if the theory would work for pointlike particles in order to predict the evolution of this field as part of the equations themselves rather than as an external element.
Measured in amperes in the International System of Units.
Heinrich Hertz's main initial experiment used a spark-gap transmitter. It is not something that transmits recorded sounds like voice: it only transmits noisy beeps. And as such was used for wireless telegraphy.
Hertz Experiment on Electromagnetic Waves by Ludic Science (2015)
Source. Simplified recreation with cheap modern equipment. Uses as transmitter power source both:- a piezo igniter from a barbequeue lighter
- a more powerful home-made transformer
Hertz and Radio waves Explained by PhysicsHigh (2016)
Source. Simple schematics showing the basics of the experiments. No choice of components rationale. Unlisted articles are being shown, click here to show only listed articles.