Surprising that anyone still thinks the Penrose model could
work. Microtubules do not exhibit harmonic motion like violin strings. The reason is that all motion at the length scale of cells or smaller is heavily overdamped.
The environment within a cell is nonintuitive. To find out more about this, read “Life at low Reynolds number” or “Mechanics of Motor Proteins and the Cytoskeleton” by Joe Howard.
Lossy compression is a bad idea for scientific images. For instance, we often need to understand the statistics of photon detection events in background regions. That’s one of the first things to get tossed.
It wasn’t entirely clear in the parts that I watched, but my understanding is that slime molds are actually “social” amoeba. They often crawl around as loners, eating whatever they can find. But if they run out of food, they start sending out chemoattractants to all of their buddies in the neighborhood. They all crawl together and create a fruiting body (a spore) that eventually will break off in the wind
and land somewhere else. Hopefully, in greener pastures. Those fruiting bodies are what you see in these videos. Amazing creatures, they live on the brink of multicellular eukaryotes.
There are many groups of slime-mold-like living beings and most of them are not closely related and they have evolved independently the ability to make multicellular fruiting bodies, as an adaptation to the life in terrestrial conditions (where an elevated position is needed to enable the dispersal of spores by the wind, like from mushrooms).
In most of these groups, they live as single amoeboid cells and they aggregate into multicellular fruiting bodies only for reproduction. Besides most such groups that are eukaryotes (nucleated cells), there is even a group of bacteria, the Myxobacteria, which have the same ability of making multicellular fruiting bodies.
Besides the many groups of slime-mold-like living beings, with similar mushroom-like fruiting bodies, there is a single group of those which have been known by humans for the longest time and which are the only for which the name "slime molds" (the English translation of Myxomycetes) should be applied in the strict sense.
For the slime molds properly, the term "social amoebae" is not appropriate as it is for the others, which live single and then aggregate into multicellular fruiting bodies.
The true slime molds spend most of their life as multicellular or multi-nucleated (so-called plasmodia) bodies, which are big enough to be seen without magnifying instruments, which is why they have been known many centuries before the others. As seen in the linked videos, the true slime molds are blobs that move slowly around, usually eating bacteria.
3% CO2 from mask wearing? I doubt it. I recently needed to measure 5% CO2, and I had to hold my breath to near-passout levels to reach 5% on the monitor. There’s no way that I could tolerate 3% for any length of time.
More likely these authors cherry-picked studies with typos in them.
Seems like the key thing would be to measure the concentration under mask during inhaling vs exhaling. Exhaled breath has many % CO2. The article references a whole table of articles measuring CO2 under masks. I haven't taken the time to check if they separate exhale vs inhale but would be curious to know.
Just thinking about the numbers. Exhaled air has 4% CO2, while fresh air has 0.04%. But if you inhale air with 3% CO2 that should add to those 4% yielding 7% exhale.
Now, in order to get 3% CO2 in your inhale this would mean that you would have to breathe in 42% stale air (with 7% CO2) mixed with 58% fresh air (~0 CO2).
Since the volume of gas trapped by a mask is miniscule compared to the lungs, I wonder if it even matters. Might be better to just try to measure blood concentrations.
Yeah I was surprised they didn't measure blood concentrations--feels like the actual metric we should care about. I remember like, a lot of mic-drop social media posts about people being like "I wore a mask for 16 straight hours and my spo2 is 100% (or whatever), quit whining"
Yep, at 0.1-0.2% (1000-2000ppm) people start to get drowsy. at 0.2-0.5% (2000-5000ppm) people get heachaches, poor concentration, elevated heart rates, etc. It's quite unpleasant. 3% is 30,000 ppm.
While wearing a mask isn't fun, I've never experienced anything to that level while wearing mine.
I'd caution you against this idea that you can "know the feeling" of acute CO2 exposure.
For my PhD work (gas geochemistry) I spent hundreds of hours working in volcanic ice caves with CO2 levels up to 2% (we measured up to 3% but had a rule against being in above 2%). I always had a gas monitor with me so it was interesting to try and guess the levels. Neither I, nor anyone I was with, could guess reliably.
More than once I was with others in a cave, and they would freak out and say they felt high CO2 and we'd check the readings and nope. I actually think people (including myself) were responding to high humidity and heat and misinterpreting it as high CO2.
Of course, high CO2 is dangerous, all I'm saying is that it's surprisingly hard to disentangle it from all the other factors affecting how well your feel as a human, when you actually test yourself.
I'm reasonably certain I notice levels above 800ppm. It's subtle, but everyone in the house starts getting a little edgy (kids and adults). Sure enough, the CO2 meter is reporting > 800.
I doubt I could differentiate between 800 and 1600 though.
In the early days of COVID, before we knew anything, I would go for runs outside and wear a mask (N95). I live in a densely populated city so this seemed like the appropriate thing to do.
While it was not pleasant, at no point did I start having issues you described so I have trouble buying the original claim.
Bit flips from cosmic rays. Earth’s magnetic field helps to shield us, but is disrupted now. I work with a CCD camera in a sub basement lab. On a normal day we see a stray cosmic ray every couple of minutes (as a hot pixel). On a day like today, might be every couple of seconds.
>> I've always been hearing that solar flares and the resulting geomagnetic storms pose danger to hard drives and electronics. Is there any truth to it?
> Bit flips from cosmic rays.
I don't think that's it. IIRC, if a geomagnetic storm/coronal mass ejection is big enough, it can cause certain effects that are similar to an EMP. What the OP is talking about sounds like a distorted version of that danger: a nuclear EMP could directly fry microelectronics, a solar storm is a kind of EMP (solar EMP), but is missing most of the effects that could directly damage microelectronics, and many people conflate the two.
Yes, but during the Carrington Event, electrical wires became overloaded and blowing out equipment attached to "the grid."
I've had a computer blow out (sparks, smoke and everything) due to a power surge when the main power went out and then back on, rapidly.
So while the "direct" causes might be different between EMP and CME, the end results are basically the same. I could only imagine what our current (very power sensitive) electronics would do in that scenario.
From the wikipedia Carrington Event you posted:
> Because of the geomagnetically induced current from the electromagnetic field, telegraph systems all over Europe and North America failed, in some cases giving their operators electric shocks.[22] Telegraph pylons threw sparks.
> I've had a computer blow out (sparks, smoke and everything) due to a power surge when the main power went out and then back on, rapidly.
> So while the "direct" causes might be different between EMP and CME, the end results are basically the same.
Not necessarily. My understanding is a CME solar EMP would take out grid-connected devices (via power surges over the grid), but leave most unconnected devices unharmed (e.g. laptops running on battery), but a nuclear EMP would take out both.
But it would also likely take out the grid itself. If all of the massive power cables strewn all over, connected to very large expensive power station transformers, become overloaded at the same time from a CME, I don't predict good things for those transformers and a lot of other things. The laptop would not be able to be recharged without solar or something. It takes a long time (1-2 years is my understanding) to get one single transformer at a power station, under ideal conditions. They are basically made to order, and backlogged.
True, but the hot pixels you see in the CCD isn't from bit flips. Rather the CCD is properly doing its job of collecting electrons. It's just that spurious electrons are being produced by the cosmic rays' ionization trail (as opposed to photoelectron in normal operation).
It’s an excitation of the sensor. It may be interpreted somewhat like a bit flip when converted to an image, but it’s normal for image sensors to experience a lot of noise, going back to the days of film. It may just be eliminated by the denoising algorithm like most spurious electrons/photons.
Bitflip is when a high energy particle changes the state of a memory address or signal in a wire.
Hot pixels are when the CCD (camera sensor) achieves its max level and becomes bright. Pixel overloaded (should also result in spillover).
Difference is really just what part of the system receives the energy. For example, you can overload a pixel with a laser, but you also should get spillover. Bit flips tend to be more localized, affecting only one part. In reality, the difference doesn't matter too much, as long as we're keeping our discussion to cosmic events. But also note that images experience a lot of (non-gaussian) noise and plenty of this is from cosmic excitation as well as from other natural and man made sources. Just the levels are a lot lower and unlikely to result in a bitflip (which is a pretty high energy event).
Pretty much this. But the point is that a bitflip would be like, your CCD was supposed to read out value 0b00000 = 0 but due to cosmic ray interference, it read out 0b10000 = 16 instead.
Instead, what's happening in GGP's experiment is that actual electrons, created in the bulk of the active silicon region by a passing cosmic ray, are getting detected by the CCD, and it will (correctly) read out some value between 00000 and 11111, depending on how many electrons it saw. In principle you can actually make a histogram of these readout values and observe the Bethe-Bloch distribution of energy loss for ionizing particles through the (very thin) bulk of silicon! On the other hand, random bit flips (which are much rarer!) would just give you a random distribution of the numbers {00000, 00001, 00010, 00100, 01000, 10000}.
I used to work as a contractor for John Deere and one of the engineers there would capriciously insist on adding runtime consistency checks in code review because "you never know if lightning might strike or a cosmic ray flips a bit in RAM". This was not for any life-or-death software, it was for the infotainment stuff which was already insanely buggy beginning with the Bosch radio we had sourced and carrying into the ambiguous protocol John Deere designed to speak with the radio and the application code the lowest-bidder contractors wrote before hiring me to fix it (lightning strikes and cosmic rays were the least of their worries).
So the radio would fail to connect to many bluetooth devices at the time (because Bosch), the application had no way of telling what state the radio (that it was meant to speak to) was in (because of the faulty protocol), and the application was riddled with other bugs (because lowest-bidder contractors), but by god it was safe from lightning and cosmic rays (except not really because they could just as easily alter the program as the state the program was operating on).
Well, the alternative was to invest the time into the many glaring concrete bugs rather than hypothetical 'cosmic ray' bit flips. I don't have a fundamental problem with runtime consistency checks if there's some compelling concern and a clear up-front policy for when/where to add them (as opposed to dealing with the whims of a capricious code reviewer).
The story goes that Mario 64 speedrunner accidentally triggered a glitch which was thought to require that a particular value is "true" (Mario is touching a ceiling) which was not in this case. The following glitch hunt had many people concluding that the most likely thing that happened was a bit-flip via cosmic radiation which caused the exact distance change which could have otherwise been caused by a different but similar glitch.
There was a famous story how Google couldn’t produce a working index for months because they used non ecc memory for their servers. This was like 20 years ago.
The environment within a cell is nonintuitive. To find out more about this, read “Life at low Reynolds number” or “Mechanics of Motor Proteins and the Cytoskeleton” by Joe Howard.
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