Quantum resistant cryptosystem Updated +Created
Universe Updated +Created
Wikipedia dumps Updated +Created
Per-table dumps created with mysqldump and listed at: dumps.wikimedia.org/. Most notably, for the English Wikipedia: dumps.wikimedia.org/enwiki/latest/
The tables are "documented" under: www.mediawiki.org/wiki/Manual:Database_layout, e.g. the central "page" table: www.mediawiki.org/wiki/Manual:Page_table. But in many cases it is impossible to deduce what fields are from those docs.
Black holes nearest to the Sun Updated +Created
Interesting to note that there are quite a few nearer than Sagittarius A, as of 2022 we know of one at 1.5 kly: universemagazine.com/en/discovered-the-closest-black-hole-to-the-sun/
It is interesting that a few months earlier there seemed to be no known specific black holes in the Milky Way: www.nasa.gov/feature/goddard/2022/hubble-determines-mass-of-isolated-black-hole-roaming-our-milky-way-galaxy although their count is estimated to be in the hundreds of millions.
For comparison, remember that the Milky Way is 185 kly in diameter x 2 kly thick.
enwiki-latest-categorylinks.sql Updated +Created
Physics 253a by Sidney Coleman (1986) Updated +Created
E. Coli K-12 MG1655 operon thrLABC Updated +Created
That page lists several components of the promoter, which we should try to understand!
After the first gene in the codon, thrL, there is a rho-independent termination. By comparing:we understand that the presence of threonine or isoleucine variants, L-threonyl and L-isoleucyl, makes the rho-independent termination become more efficient, so the control loop is quite direct! Not sure why it cares about isoleucine as well though.
TODO which factor is actually specific to that DNA region?
enwiki-latest-category.sql Updated +Created
dumps.wikimedia.org/enwiki/latest/enwiki-latest-category.sql.gz contains a list of categories. It only contains the categories and some counts, but it doesn't contain the subcategories and pages under each category, so it is a bit pointless.
The SQL first defines the table:
CREATE TABLE `category` (
  `cat_id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `cat_title` varbinary(255) NOT NULL DEFAULT '',
  `cat_pages` int(11) NOT NULL DEFAULT 0,
  `cat_subcats` int(11) NOT NULL DEFAULT 0,
  `cat_files` int(11) NOT NULL DEFAULT 0,
  PRIMARY KEY (`cat_id`),
  UNIQUE KEY `cat_title` (`cat_title`),
  KEY `cat_pages` (`cat_pages`)
) ENGINE=InnoDB AUTO_INCREMENT=249228235 DEFAULT CHARSET=binary ROW_FORMAT=COMPRESSED;
followed by a few humongous inserts:
INSERT INTO `category` VALUES (2,'Unprintworthy_redirects',1597224,20,0),(3,'Computer_storage_devices',88,11,0)
which we can see at: en.wikipedia.org/wiki/Category:Computer_storage_devices
Se see that en.wikipedia.org/wiki/Category:Computer_storage_devices_by_company
so it contains only categories.
We can check this with:
sed -s 's/),/\n/g' enwiki-latest-category.sql | grep Computer_storage_devices
and it shows:
(3,'Computer_storage_devices',88,11,0
(521773,'Computer_storage_devices_by_company',6,6,0
There doesn't seem to be any interlink between the categories, only page and subcategory counts therefore.
Epsilon (letter) Updated +Created
Confusingly, in LaTeX:
  • \varepsilon rendered , is the default modern Greek glyph
  • \epsilon rendered is the lunate variant
Erhu Updated +Created
Figure 1.
A blind erhu street performer playing in Jingzhou, Hubei (2006)
Source. Playing the erhu is a traditional occupation for blind people in China, a notable example being Abing.
Video 1.
Suwu herding sheep played by Song Fei (2017)
Source.
Video 2.
The 12 Most Famous Erhu Melodies in China (2021)
Source. TODO transcribe list.
Quantum Information course of the University of Oxford Hilary 2023 Updated +Created
This section is about the version of the course offerece on Hilary term 2023 (January).
2006 Nobel Prize in Physics Updated +Created
Type of processor Updated +Created
A Mathematician's Apology Updated +Created
With major mathematicians holding ideas such as:
Exposition, criticism, appreciation, is work for second-rate minds. [...] It is a melancholy experience for a professional mathematician to find himself writing about mathematics. The function of a mathematician is to do something, to prove new theorems, to add to mathematics, and not to talk about what he or other mathematicians have done.
it is not surprise that the state of STEM education is so shit as of 2020, especially at the the missing link between basic and advanced! This also implies that the number of people that can appreciate any advanced mathematics research is tiny, and consequently so is the funding.
Analog computer Updated +Created
Some of the earlier computers of the 20th centure were analog computers, not digital.
At some point analog died however, and "computer" basically by default started meaning just "digital computer".
As of the 2010's and forward, with the limit of Moore's law and the rise of machine learning, people have started looking again into analog computing as a possile way forward. A key insight is that huge floating point precision is not that crucial in many deep learning applications, e.g. many new digital designs have tried 16-bit floating point as opposed to the more traditional 32-bit minium. Some papers are even looking into 8-bit: dl.acm.org/doi/10.5555/3327757.3327866
As an example, the Lightmatter company was trying to implement silicon photonics-based matrix multiplication.
A general intuition behind this type of development is that the human brain, the holy grail of machine learning, is itself an analog computer.
Blockchain.info Updated +Created
TODO who owns it? Are they reliable?
This helper dumps a transaction JSON to a binary:
bitcoin-tx-out-scripts() (
    # Dump data contained in out scripts. Remove first 3 last 2 bytes of
    # standard transaction boilerplate.
    h="$1"
    echo curl "https://blockchain.info/tx/${h}?format=json" |
    jq '.out[].script' tmp.json |
    sed 's/"76a914//;s/88ac"//' |
    xxd -r -p > "${h}.bin"
)
Their API limit witout key is 1 query per 10 seconds!!!
Erwin Schrödinger Updated +Created
Provably quantum secure encryption algorithm Updated +Created
None known as of 2020.

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