Laser spectrum Created 2024-06-26 Updated 2025-07-16
Video 1.
Spectrum of laser light by Shaoul Ezekiel
. Source. 2008, MIT.
Twisted pair Created 2024-06-26 Updated 2025-07-16
Education of André-Marie Ampère Created 2024-06-26 Updated 2025-07-16
en.wikipedia.org/w/index.php?title=Andr%C3%A9-Marie_Amp%C3%A8re&oldid=1211946256:
Jean-Jacques Ampère, a successful merchant, was an admirer of the philosophy of Jean-Jacques Rousseau, whose theories of education (as outlined in his treatise Émile) were the basis of Ampère's education. Rousseau believed that young boys should avoid formal schooling and pursue instead a "direct education from nature." Ampère's father actualized this ideal by allowing his son to educate himself within the walls of his well-stocked library.
TODO find the source for this.
Electrical cable Created 2024-06-26 Updated 2025-07-16
One more more electrical wires surrounded by an insulator.
Oliver Heaviside Created 2024-06-26 Updated 2025-07-16
He participated in the development of the electrical telegraph, and he did some good modeling work that improved the foundations of the field, notably creating the telegrapher's equations.
He was one of those idealists who just want to do some cool work even if they have to starve for it, people had to get a state pension for him for his contributions. Nice guy. en.wikipedia.org/w/index.php?title=Oliver_Heaviside&oldid=1230097796#Later_years_and_views:
In 1896, FitzGerald and John Perry obtained a civil list pension of £120 per year for Heaviside, who was now living in Devon, and persuaded him to accept it, after he had rejected other charitable offers from the Royal Society.
He also never married: www.nndb.com/people/627/000204015/
Figure 1.
Oliver Heaviside c. 1900
. Source.
We intersect 2013 DNS Census virtual host cleanup with 2013 DNS census MX records and that leaves 460k hits. We did lose a third on the the MX records as of 260 hits since secureserver.net is only used in 1/3 of sites, but we also concentrate 9x, so it may be worth it.
Then we Wayback Machine CDX scanning. it takes about 5 days, but it is manageale.
We did a full Wayback Machine CDX scanning for JAR, SWF and cgi-bin in those, but only found a single new hit:
Idaho stop Updated 2025-07-16
The traffic is designed for cars, which makes many red stops for bicycles completely stupid.
In a bicycle you just have too much more control and awareness than in a car, so if the way is completely clear, you should be allowed to stop, look if the way is clear, and then run reds.
Of course, this does increase the chances of hitting pedestrians a little bit. But the risk change feels so little that it would be worth it. Studies quoted by Wikipedia corroborate. It just feels extremely unintuitive to make cyclists stop in certain places when the street is clear.
Abel-Ruffini theorem Updated 2025-07-16
Video 1.
But why is there no quintic formula? by MathKiwi
. Source. 10 minutes, that's about the right length, well done.
Abjad Updated 2025-07-16
Unlike abugida, these actually make you guess vowels, which are mostly or all not written down in any way. Terrible.
E.g.: the main Arabic script.
Identity theorem Updated 2025-07-16
Essentially, defining an holomorphic function on any open subset, no matter how small, also uniquely defines it everywhere.
This is basically why it makes sense to talk about analytic continuation at all.
One way to think about this is because the Taylor series matches the exact value of an holomorphic function no matter how large the difference from the starting point.
Therefore a holomorphic function basically only contains as much information as a countable sequence of numbers.
A blog in every web framework Updated 2025-07-16
A (multi-user) blog is the hello world of the web, so creating one of those is the best way to quickly evaluate web technology, i.e. time to Hello World.
Some new frameworks like FeathersJS are making a chat app instead, as that highlights the push notifications a bit better.
Abortion Updated 2025-07-16
Ciro Santilli is for abortion rights of women, until very late in pregnancy.
But it's not something that he would do himself, unless under extreme cases.
Gel electrophoresis Updated 2025-07-16
Technique widely used to measure the size of DNA strands, most often PCR output of a region of interest.
A simple sample application is gel electrophoresis alelle determination.
Generalized coordinate Updated 2025-07-16
The variables of the Lagrangian, e.g. the angles of a double pendulum. From that example it is clear that these variables don't need to be simple things like cartesian coordinates or polar coordinates (although these tend to be the overwhelming majority of simple case encountered): any way to describe the system is perfectly valid.
In quantum field theory, those variables are actually fields.

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