Immortalised cell line Updated +Created
Image editor Updated +Created
a Updated +Created
It is the norm induced by the complex dot product over :
Cycling in the United Kingdom Updated +Created
The United Kingdom is a great place to cycle in general as there's plenty of small country roads and interesting new small towns to discover, perhaps much like the rest of Europe, as opposed to the United States, which likely has some huge infinitely long straight roads with a lot of nothing in between.
Of particular interest is the large amount of airfields and small air raid shelters in the fields, an ominous reminder of world war 2. The airfields are in various states, from functional military fields, many converted to civilian usage, some have barely any tarmac left but still see usage. And some were just completely abandoned and decayed and became recreation grounds and farms. The UK is therefore also a great place to be if you want to learn to fly as a hobby!
Rail transport in Great Britain Updated +Created
Sylvain Poirier Updated +Created
Ciro Santilli feels a bit like this guy:
singlesunion.org/ so cute, he's looking for true love!!! This is something Ciro often thinks about: why it is so difficult to find love without looking people in the eye. The same applies to jobs to some extent. He has an Incel wiki page: incels.wiki/w/Sylvain_Poirier :-)
Figure 1.
Sylvain's photo from his homepage.
Source. He's not ugly at all! Just a regular good looking French dude.
Video 1.
Why learn Physics by yourself by Sylvain Poirier (2013)
Source.
Interference pattern Updated +Created
What you see along a line or plane in a wave interference.
Notably used for the pattern of the double-slit experiment.
Brazilian Student Association Updated +Created
This is a good initiative. Since the government is incapable of doing shit in this area, individuals have to do it themselves.
They even have a scholarship program...: www.bolsas.gobrasa.org/
Jean-Luc Ponty Updated +Created
Video 1.
Jean-Luc Ponty Live in Chicago on "Soundstage" (1976)
Source.
Matthew Heaney Updated +Created
Ciência sem Fronteiras Updated +Created
Symplectic group Updated +Created
Intuition, please? Example? mathoverflow.net/questions/278641/intuition-for-symplectic-groups The key motivation seems to be related to Hamiltonian mechanics. The two arguments of the bilinear form correspond to each set of variables in Hamiltonian mechanics: the generalized positions and generalized momentums, which appear in the same number each.
Seems to be set of matrices that preserve a skew-symmetric bilinear form, which is comparable to the orthogonal group, which preserves a symmetric bilinear form. More precisely, the orthogonal group has:
and its generalization the indefinite orthogonal group has:
where S is symmetric. So for the symplectic group we have matrices Y such as:
where A is antisymmetric. This is explained at: www.ucl.ac.uk/~ucahad0/7302_handout_13.pdf They also explain there that unlike as in the analogous orthogonal group, that definition ends up excluding determinant -1 automatically.
Therefore, just like the special orthogonal group, the symplectic group is also a subgroup of the special linear group.
Telomere Updated +Created
grep Updated +Created
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".
Tangent space Updated +Created
TODO what's the point of it.
Bibliography:
tcpdump Updated +Created
To test it, let's get two computers on the same local area network, e.g. connected to Wi-Fi on the same home modem router.
On computer B:
On computer A, run on terminal 1:
sudo tcpdump ip src 192.168.1.102 or dst 192.168.1.102
Then on terminal 2 make a test request:
curl 192.168.1.102:8000
Output on terminal 1:
17:14:22.017001 IP ciro-p14s.55798 > 192.168.1.102.8000: Flags [S], seq 2563867413, win 64240, options [mss 1460,sackOK,TS val 303966323 ecr 0,nop,wscale 7], length 0
17:14:22.073957 IP 192.168.1.102.8000 > ciro-p14s.55798: Flags [S.], seq 1371418143, ack 2563867414, win 65160, options [mss 1460,sackOK,TS val 171832817 ecr 303966323,nop,wscale 7], length 0
17:14:22.074002 IP ciro-p14s.55798 > 192.168.1.102.8000: Flags [.], ack 1, win 502, options [nop,nop,TS val 303966380 ecr 171832817], length 0
17:14:22.074195 IP ciro-p14s.55798 > 192.168.1.102.8000: Flags [P.], seq 1:82, ack 1, win 502, options [nop,nop,TS val 303966380 ecr 171832817], length 81
17:14:22.076710 IP 192.168.1.102.8000 > ciro-p14s.55798: Flags [P.], seq 1:80, ack 1, win 510, options [nop,nop,TS val 171832821 ecr 303966380], length 79
17:14:22.076710 IP 192.168.1.102.8000 > ciro-p14s.55798: Flags [.], ack 82, win 510, options [nop,nop,TS val 171832821 ecr 303966380], length 0
17:14:22.076727 IP ciro-p14s.55798 > 192.168.1.102.8000: Flags [.], ack 80, win 502, options [nop,nop,TS val 303966383 ecr 171832821], length 0
17:14:22.077006 IP ciro-p14s.55798 > 192.168.1.102.8000: Flags [F.], seq 82, ack 80, win 502, options [nop,nop,TS val 303966383 ecr 171832821], length 0
17:14:22.077564 IP 192.168.1.102.8000 > ciro-p14s.55798: Flags [F.], seq 80, ack 82, win 510, options [nop,nop,TS val 171832821 ecr 303966380], length 0
17:14:22.077578 IP ciro-p14s.55798 > 192.168.1.102.8000: Flags [.], ack 81, win 502, options [nop,nop,TS val 303966384 ecr 171832821], length 0
17:14:22.079429 IP 192.168.1.102.8000 > ciro-p14s.55798: Flags [.], ack 83, win 510, options [nop,nop,TS val 171832824 ecr 303966383], length 0
TODO understand them all! Possibly correlate with Wireshark, or use -A option to dump content.
Are there infinitely many Mersenne primes? Updated +Created
Closed standard Updated +Created
ISO is the main culprit of this bullshit, some notable examples related to open source software:
The only low level thing that escaped this was OpenGL via Khronos, what heroes those people are.
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. .
Kerckhoffs's principle Updated +Created
Basically the opposite of security through obscurity, though slightly more focused on cryptography.
KEGG Updated +Created
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.

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