Human protein Updated 2025-07-16
Luxury goods Updated 2025-07-16
One of the things Ciro Santilli most deeply despises.
Real luxury is to understand quantum field theory and number theory.
Music Updated 2025-07-16
Ciro Santilli took courses once upon a time, maybe that has influenced his passion? Ciro Santilli's musical education.
Pornography Updated 2025-07-16
Public speaking Updated 2025-07-16
Disk encryption password handover plausible deniability Updated 2025-07-16
Can the last disk access times be checked via forensic methods?
Disk read-and-write head Updated 2025-07-16
Distribution (mathematics) Updated 2025-07-16
Generalize function to allow adding some useful things which people wanted to be classical functions but which are not,
It therefore requires you to redefine and reprove all of calculus.
For this reason, most people are tempted to assume that all the hand wavy intuitive arguments undergrad teachers give are true and just move on with life. And they generally are.
One notable example where distributions pop up are the eigenvectors of the position operator in quantum mechanics, which are given by Dirac delta functions, which is most commonly rigorously defined in terms of distribution.
Distributions are also defined in a way that allows you to do calculus on them. Notably, you can define a derivative, and the derivative of the Heaviside step function is the Dirac delta function.
Divergence in Einstein notation Updated 2025-07-16
Don Lincoln Updated 2025-07-16
Publishes through the Fermilab YouTube channel under the playlist "Fermilab - Videos by Don Lincoln"
Some insights, but too much on the popular science side of things.
Do one thing and do it well Updated 2025-07-16
Is this exact sentence really from UNIX philosophy? en.wikipedia.org/wiki/Unix_philosophy#Do_One_Thing_and_Do_It_Well
Of course, it has precedents, e.g. jack of all trades, master of none
Do superconductors carry infinite current? Updated 2025-07-16
No, see: superconductor I-V curve.
Bibliography:
- physics.stackexchange.com/questions/62664/how-can-ohms-law-be-correct-if-superconductors-have-0-resistivity on Physics Stack Exchange
- physics.stackexchange.com/questions/69222/how-can-i-put-a-permanent-current-into-a-superconducting-loop
- www.quora.com/Do-superconductors-produce-infinite-current-I-V-R-R-0-How-do-they-fit-into-quantum-theory
- www.reddit.com/r/askscience/comments/dcgdf/does_superconductivity_imply_infinite_current/
- www.reddit.com/r/askscience/comments/7xhb46/what_would_happen_if_a_voltage_was_applied_to_a/
Double-slit experiment Updated 2025-07-16
Amazingly confirms the wave particle duality of quantum mechanics.
The effect is even more remarkable when done with individual particles such individual photons or electrons.
Richard Feynman liked to stress how this experiment can illustrate the core ideas of quantum mechanics. Notably, he night have created the infinitely many slits thought experiment which illustrates the path integral formulation.
Nested set model Updated 2025-07-16
This is particularly important in SQL: Nested set model in SQL, as it is an efficient way to transverse trees there, since querying parents every time would require multiple disk accesses.
The ASCII art visualizations from stackoverflow.com/questions/192220/what-is-the-most-efficient-elegant-way-to-parse-a-flat-table-into-a-tree/194031#194031 are worth reproducing.
As the sets:
__________________________________________________________________________
| Root 1 |
| ________________________________ ________________________________ |
| | Child 1.1 | | Child 1.2 | |
| | ___________ ___________ | | ___________ ___________ | |
| | | C 1.1.1 | | C 1.1.2 | | | | C 1.2.1 | | C 1.2.2 | | |
1 2 3___________4 5___________6 7 8 9___________10 11__________12 13 14
| |________________________________| |________________________________| |
|__________________________________________________________________________|Consider the following nested set:
0, 8, root
1, 7, mathematics
2, 3, geometry
3, 6, calculus
4, 5, derivative
5, 6, integral
6, 7, algebra
7, 8, physics Nested set model in SQL Updated 2025-07-16
How to implement Nested set model in SQL:
- stackoverflow.com/questions/192220/what-is-the-most-efficient-elegant-way-to-parse-a-flat-table-into-a-tree/42781302#42781302 contains the correct left/size representation and update queries, which makes it much easier to maintain the tree without having to worry about the sizes of siblings which are constant
- stackoverflow.com/questions/192220/what-is-the-most-efficient-elegant-way-to-parse-a-flat-table-into-a-tree/194031#194031 amazing ASCII art representations of the structure. Unfortunately uses a wonky left/right representation, rather than the much more natural left/size representation from the other post
Neuralink Updated 2025-07-16
- youtu.be/CLUWDLKAF1M?t=380 Shows a pig with the implant, and live signals are shown when its nose touches something.
- youtu.be/CLUWDLKAF1M?t=536 shows a pre-recorded pig study correlating really the joint positions while walking with the neuralink signals
NeuroMechFly Updated 2025-07-16
Dr. Strangelove Updated 2025-07-16
Dual space Updated 2025-07-16
The dual space of a vector space , sometimes denoted , is the vector space of all linear forms over with the obvious addition and scalar multiplication operations defined.
Since a linear form is completely determined by how it acts on a basis, and since for each basis element it is specified by a scalar, at least in finite dimension, the dimension of the dual space is the same as the , and so they are isomorphic because all vector spaces of the same dimension on a given field are isomorphic, and so the dual is quite a boring concept in the context of finite dimension.
Infinite dimension seems more interesting however, see: en.wikipedia.org/w/index.php?title=Dual_space&oldid=1046421278#Infinite-dimensional_case
Dulong-Petit law Updated 2025-07-16
It can be seen as the limit case of an Einstein solid at high temperatures. At lower temperatures, the heat capacity depends on temperature.
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