Polymerase chain reaction Updated 2025-07-16
This is an extremely widely used technique as of 2020 and much earlier.
If allows you to amplify "any" sequence of choice (TODO length limitations) between a start and end sequences of interest which you synthesize.
If the sequence of interest is present, it gets amplified exponentially, and you end up with a bunch of DNA at the end.
You can then measure the DNA concentration based on simple light refraction methods to see if there is a lot of DNA or not in the post-processed sample.
Even Ciro Santilli had some contact with it at: Section "How to use an Oxford Nanopore MinION to extract DNA from river water and determine which bacteria live in it", see: PCR!
One common problem that happens with PCR if you don't design your primers right is: en.wikipedia.org/wiki/Primer_dimer
Sometime it fails: www.reddit.com/r/molecularbiology/comments/1kouomw/when_your_pcr_fails_again_and_you_start/and a comment:
Nothing humbles you faster than a bandless gel. One minute you’re a scientist, the next you’re just a pipette-wielding wizard casting spells that don’t work. Meanwhile, physicists are out there acting like gravity always behaves. Smash that upvote if your reagents have ever gaslit you.
PCR = Pray, Cry, Repeat
Politics of Europe Updated 2025-07-16
Poincaré sphere Updated 2025-07-16
In it, each of the six sides has a clear and simple to understand photon polarization state, either of:
The sphere clearly suggests for example that a rotational or diagonal polarizations are the combination of left/right with the correct phase. This is clearly explained at: Video "Quantum Mechanics 9b - Photon Spin and Schrodinger's Cat II by ViaScience (2013)".
Lord of the Rings character Updated 2025-07-16
Loop (topology) Updated 2025-07-16
London Updated 2025-07-16
Yung Professional Move to London by Sans Beanstalk
. Source. The sad thing is that the same author also has another accurate video criticizing British suburbia, so there's no escape basically in the UK: www.youtube.com/watch?v=oIJuZbXLZeY.
Video "Being a Dickhead's Cool by Reuben Dangoor (2010)" also comes to mind.
LLVM IR vs C Updated 2025-07-16
List of version control systems Updated 2025-07-16
List of Stack Overflow users Updated 2025-09-09
List of nuclear weapons Updated 2025-07-16
List of books Updated 2025-11-05
List of anatomical systems Updated 2025-07-16
List of AI games Updated 2025-07-16
Lines through origin model of the real projective plane Updated 2025-07-16
This is the standard model.
Line (geometry) Updated 2025-07-16
Linear operator Updated 2025-07-16
Examples:
- a 2x2 matrix can represent a linear map from to , so which is a linear operator
- the derivative is a linear map from to , so which is also a linear operator
Secrets (Allan Holdsworth album) Updated 2025-07-16
Secrets Allan Holdsworth album
. Source. Second quantization Updated 2025-07-16
Second quantization also appears to be useful not only for relativistic quantum mechanics, but also for condensed matter physics. The reason is that the basis idea is to use the number occupation basis. This basis is:
- convenient for quantum field theory because of particle creation and annihilation changes the number of particles all the time
- convenient for condensed matter physics because there you have a gazillion particles occupying entire energy bands
Bibliography:
- www.youtube.com/watch?v=MVqOfEYzwFY "How to Visualize Quantum Field Theory" by ZAP Physics (2020). Has 1D simulations on a circle. Starts towards the right direction, but is a bit lacking unfortunately, could go deeper.
Second law of thermodynamics Updated 2025-07-16
Subtle is the Lord by Abraham Pais (1982) chapter 4 "Entropy and Probability" mentions well how Boltzmann first thought that the second law was an actual base physical law of the universe while he was calculating numerical stuff for it, including as late as 1872.
But then he saw an argument by Johann Joseph Loschmidt that given the time reversibility of classical mechanics, and because they were thinking of atoms as classical balls as in the kinetic theory of gases, then there always exist a valid physical state where entropy decreases, by just reversing the direction of time and all particle speeds.
So from this he understood that the second law can only be probabilistic, and not a fundamental law of physics, which he published clearly in 1877.
Pleistocene Updated 2025-07-16
Agriculture is not the official definition of the age. But it is good enough. Likely related to the official end of glaciations thing.
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