Germline Updated 2025-07-16
It is quite mind blowing when you think about it, that the huge majority of your body's cells is essentially just there to support a tiny ammount of germline, which are the only cells that can actually pass on! It is fun to imagine the cell type tree for this, with a huge branching of somatic cells, and only a few germline going forward.
Post-order depth-first search Updated 2025-07-16
Has the property of visiting all descendants before the parent.
Pre-order depth-first search Updated 2025-07-16
This is the order in which you would want to transverse to read the chapters of a book.
Like breadth-first search, this also has the property of visiting parents before any children.
Note that:
and for that to be true for all possible and then we must have:
i.e. the matrix inverse is equal to the transpose.
Conversely, if:
is true, then
These matricese are called the orthogonal matrices.
TODO is there any more intuitive way to think about this?
A Mathematician's Apology Updated 2025-07-16
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.
Amazon anticompetitive acquisition Updated 2025-07-16
Amazon is apparently notorious for having bought off many competitors, many of them just to kill off the competition and clear the way, not to actually reuse them.
youtu.be/tfAhTtBlb2Q?t=849 from Video "Jeff Bezos Revealed by Bloomberg (2015)" clearly shows Tim O'Reilly saying that very clearly about Bezos.
I do know of a number of cases in which he [Bezos] has acquired companies in order to take out competitors, potential future competitors. Rather than because he actually wants that business to continue.
Perhaps O'Reilly who is the bookselling business is not the greatest fan of Jeff. But still. My God.
www.yalelawjournal.org/pdf/e.710.Khan.805_zuvfyyeh.pdf Amazon's Antitrust Paradox by Lina M . Khan from The Yale Law Journal raises this incredible issue.
GNU screen Updated 2025-07-16
Most important things to know:
Suona Updated 2025-07-16
One of the most flashy chinese musical instrument!
It is very similar to the Indian shehnai.
Video 1.
Wang Jin beats Gao Qiu theme music from The Water Margin
. Source.
Amazon EC2 hello world Updated 2025-07-16
Let's get SSH access, instal a package, and run a server.
As of December 2023 on a t2.micro instance, the only one part of free tier at the time with advertised 1 vCPU, 1 GiB RAM, 8 GiB disk for the first 12 months, on Ubuntu 22.04:
$ free -h
               total        used        free      shared  buff/cache   available
Mem:           949Mi       149Mi       210Mi       0.0Ki       590Mi       641Mi
Swap:             0B          0B          0B
$ nproc
1
$ df -h /
Filesystem      Size  Used Avail Use% Mounted on
/dev/root       7.6G  1.8G  5.8G  24% /
To install software:
sudo apt update
sudo apt install cowsay
cowsay asdf
Once HTTP inbound traffic is enabled on security rules for port 80, you can:
while true; do printf "HTTP/1.1 200 OK\r\n\r\n`date`: hello from AWS" | sudo nc -Nl 80; done
and then you are able to curl from your local computer and get the response.
AMD Updated 2025-07-16
Video 1.
How AMD went from nearly Bankrupt to Booming by Brandon Yen (2021)
Source.

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