Radium Updated 2025-07-16
Discovered by Marie Curie when she noticed that there was some yet unknown more radioactive element in their raw samples, after uranium and polonium, which she published 6 months prior, had already been separated. Published on December 1989 as: Section "Sur une nouvelle substance fortement radio-active, contenue dans la pechblende".
The uranium 238 decay chain is the main source of naturally occurring radium.
Uranium Updated 2025-07-16
Plutonium Updated 2025-07-16
What a material:
- only exists in trace amounts in nature,but it can be produced at kilogram scale in breeder reactors
- it is only intentionally produced for one application, and one application only basically: nuclear weapons
DuPont Updated 2025-07-16
Multivariable chain rule Updated 2025-07-16
Quaternion Updated 2025-07-16
Kind of extends the complex numbers.
Some facts that make them stand out:
- one of the only three real associative division algebras in addition to the real numbers and complex numbers, according to the classification of associative real division algebras
- the simplest non-commutative division algebra. Contrast for example with complex numbers where multiplication is commutative
Octonion Updated 2025-07-16
Unlike the quaternions, it is non-associative.
Sedenion Updated 2025-07-16
National Physical Laboratory Updated 2025-07-16
Mind uploading Updated 2025-07-16
Wikipedia defines Mind uploading as a synonym for whole brain emulation. This sounds really weird, as "mind uploading" suggests much more simply brain dumping, or perhaps reuploading a brain dump to a brain.
Superintelligence by Nick Bostrom (2014) section "Whole brain emulation" provides a reasonable setup: post mortem, take a brain, freeze it, then cut it into fine slices with a Microtome, and then inspect slices with an electron microscope after some kind of staining to determine all the synapses.
Likely implies AGI.
Zettelkasten Updated 2025-07-16
zettelkasten.de/posts/overview/ mentions one page to rule them all:
How many Zettelkästen should I have? The answer is, most likely, only one for the duration of your life. But there are exceptions to this rule.
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
Initial condition Updated 2025-07-16
Basically a subset of the boundary condition for when one of the parameters is time and we are specifying values for the time 0.
Boundary value problem Updated 2025-07-16
Dirichlet boundary condition Updated 2025-07-16
Specifies fixed values.
Can be used for elliptic partial differential equations and parabolic partial differential equations.
Numerical examples:
Neumann boundary condition Updated 2025-07-16
Specifies the derivative in a direction normal to the boundary.
Can be used for elliptic partial differential equations and parabolic partial differential equations.
Time dependent boundary condition Updated 2025-07-16
Most commonly, boundary conditions such as the Dirichlet boundary condition are taken to be fixed values in time.
Disqus Updated 2025-07-16
Biosafety level Updated 2025-07-16
Tissue engineering Updated 2025-07-16
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