sannee

Modern Android actually does support disk encryption. And the Pixels even have TPMs that should (?) safeguard the key, preventing offline brute forcing the unlock pattern. I wonder what happened here that this did not work...

Generating functions are already there (that is just math-speak for the Z-transform).

Possibly an artificial "salt lick" [1] that got displaced from its original position.

[1] https://en.wikipedia.org/wiki/Mineral_lick

Is it just me or does the app get rather unacceptable drawing latency after the screen is somewhat filled?

On the other hand, I like that it actually handles pressure, though even the thinnest pen size is rather thick at the default zoom level and kind of hard to write with.

Yeah, I do not think I have a good source at hand, this is a fun fact from an E&M lecture we had.

I also wonder if anyone actually experimented with microwaving their dinner at 10GHz or if that was just an educated guess. X-band magnetrons for radars are widely available though, so I would not be surprised if that was coming from practical experience...

To expand, apparently microwaving food right at the absorption peak sucks because of low penetrance, heating only the top layer of the food. The reason 2.4 GHz was chosen was purely as that is where the ISM band already was at the time.

Supporting the LaTeX expansion is just a necessary feature of any Julia-compatible code editor. It is not then particularly more difficult to type `\sigma` over `sigma`.

Also note that other languages often support non-ASCII identifiers as well --- for example, `σ` is a completely valid identifier name in Python (though it is more restrictive than Julia, `σ²` is not valid in Python and yet is valid in Julia). It even works in C, but that might just be a GNU extension.

To be honest, just dealing with this once can make you remember it for eternity.

For example, I know that if I want to declare a computer peripheral to the customs, there is a good chance to get the correct TARIC code in the chapter that literally starts with "Nuclear reactors"...

I, for one, am happy that I can get enough parts for a prototype run even if at 5x the price.

Especially as otherwise, those parts would just get sold to the car manufacturers and would be used to make ethically questionable products.

> Perhaps the idea was that you get a fast connection resume

This seems unlikely for the reasons you listed. Since USB is a polled bus and has shared bandwidth, implementing the flow control is likely very beneficial in case the bus can't temporarily handle the full Ethernet speed.

So, a USB-to-Ethernet gizmo just monitors its internal Ethernet-to-USB queue and if it starts to overflow, it attempts to flow control the switch. But, if no USB host is connected, no USB data requests ever arrive, the queue overflows and never gets cleared...

There may also be some WoL/USB remote wakeup stuff at play, which may be why these ICs do not drop the link on USB host disconnect by default. In fact, I wonder if messing with those settings on the host side could remediate the issue...

v0.11.0-rc2 got released around two weeks ago. But I never had any issues using the v0.10.0 for what it's worth. If your debugger and MCU are supported, there is not much that could go wrong.

Is this an accuracy or precision issue? I am imagining that if you actually have access to the device, you could do as many runs as you want, getting to arbitrarily low error rates.

Let me sketch a way to get the determinant basis-free:

Say we live in an n-dimensional vector space V and have an endomorphism f : V -> V. Now, we consider the pullback [1] f* : Λⁿ(V) -> Λⁿ(V) induced by f on the vector space of n-linear alternating forms Λⁿ(V) on V.

This is just an endomorphism on Λⁿ(V). However, Λⁿ(V) is one-dimensional, hence necessarily invariant under f*. This means f* has an eigenvalue (!). This eigenvalue is what we usually call the determinant of f.

This is completely independent of any choice of basis, orientation, or an inner product.

[1] That is, given an element w ∈ Λⁿ(V) and an arbitrary n-tuple v₁, ..., vₙ of vectors from V, we have (f*w)(v₁, ..., vₙ) = w(f(v₁), ..., f(vₙ))

This was apparently one of the story points in Fish to Mars by Peter Watts ( https://www.rifters.com/crawl/?p=8217 ).

This lecture series by Frederic Schuller is pretty amazing:

https://www.youtube.com/watch?v=GbqA9Xn_iM0&list=PLPH7f_7Zlz...

Notably, it treats QM with much more rigor than is usual in introductory courses, so having a nontrivial mathematical background is not an obstacle.

Using a proper microscope for soldering was definitely one of the most useful things I learned as a high schooler interning in an electronics lab.

I am still surprised that this is not more common. Even a biology-grade binocular microscope for 100$-ish makes a huge difference.

I spent quite some time being confused about this.

In differential geometry, we traditionally parametrize curves by a parameter "t" and think of it as "time", so the parametrization allows us to "walk along" a curve. This is very intuitive geometrically of course.

But in relativity, we also have a "time" coordinate (or at least a timelike unit-length tangent vectors), which then completely oposes this geometric intuition about curves.

Of course now physicists decide to rename well-established concepts and start calling "arc length parametrization" by "proper time parametrization", which makes it sound like it is something special, while it, as far as I can tell, has no actual physical meaning.

The Debian ripgrep binary is 5.1MB. That would consume over 15% of a 32MB flash, which is the common constraint you have to work with in many (actually, discounting Android, it might even be most) Linux deployments.

Altought the answers so far posted are not exactly incorrect, it is also important to note that the geometry (that is, a cylinder for optical fibers) of the waveguide used influences the group velocity of the propagating electromagnetic field.

This will always end up being slower than a plane wave in the same material, usually only somewhere between 10%-90% (and this also depends on the wavelength) of the free-space group velocity.

Note that projective spaces are not vector spaces. There is no meaningful way of adding vectors nor multiplying by a scalar.

Meaning we have to be very careful about treating our projective transformations as linear maps, as they are, in fact, nothing like that.

Of course people doing graphics often pick a section of the projective space ("last component is 1"), then map that onto R^3 and off they go, sort of ignoring the "planes at infinity" and praying for the best. This is messy but I do not see a better way.

LADR is probably the best linear algebra book around. It's a bit of a shame that the "marketing" mostly involves the fact that it does not use determinants.

The last edition also contains chapters on stuff like dual spaces and quotient spaces, which are important yet very often missing in other textbooks.

That being said, his reliance on C/R in about half the book could be a problem for people with CS background. Like, what if I want to compute determinants of linear maps which are over Z_2? There are also no chapters on number wrangling (like the gaussian elimination and friends), which is a big plus in my view but possibly a problem for others.

Julia positions itself not as a Python alternative, but as a Matlab alternative. People also sometimes use Python as a Matlab alternative and hence would use Julia as an alternative to Python only by transitivity.

I know that qPCR is preferred for diagnostics, but is it actually necessary? As in, will the false positive/false negative rates suffer enough for standard RT-PCR to be useless?

Glad I am not the only one finding this extremely frustrating. At least mathematicians tend to be much more explicit than engineers. Unfortunately not every topic which uses probability has a textbook written by a mathematician available.

Oh you sweet summer child. If you want to buy a laptop these days, you have to shell out 300$ for what is basically half of the motherboard and connect it externally over USB-C.

I can still find stuff like amoxicilline, ketoconazole or paracetamol on Alibaba. Maybe the ban is only on some specific chemicals?

Did you need to handle the customs paperwork? I find it hard to believe the customs would just ignore a bunch of strange powder coming through the mail...

And even if they did believe you it was not cocaine, I would still assume they would not be happy about someone importing a prescription drug.

It's usually done to prevent cheap chinese clones of your boards, not so much for security.

You can still provide a write-only bootloader interface (over UART or whatever) to allow for firmware updates.

Bose apparently already does something like this. See Bose Hear.