Firther
I bring this up because recent studies have managed to account for the saccade error associated with return sweeps and have found that reducing said error does not increase reading speed or comprehension.
https://link.springer.com/article/10.3758/s13414-019-01742-3
It's also worth noting that studies done on print line length aren't applicable to screen line length, and that most studies deal with lines of 30-100cpl, sometimes up to 130cpl, which isn't enough most websites rendered on a 16:9 screen or even the current Wikipedia design (on my 1080p monitor at least).
Maybe your textbooks just don't distribute problems well enough, the curriculum changes drastically such that what you've just learned isn't touched on again before you forget it, or maybe you just don't have the time or material to consistently practice foreign languages for 1-2 hours a day. In these cases, the 10-20 minutes spent reviewing cards serves as a useful crutch in preventing that information being forgotten entirely, which undoes all the time spent trying to learn it in the first place.
The full study can be found as the first article in this pdf: http://tobacco.cleartheair.org.hk/wp-content/uploads/2018/01...
This says nothing about rates of other non-site specific cancers of course (pancreatic being a big one), or the other health risks that are still associated with smokeless tobacco (stroke, cardiovascular disease, impotency), but it's somewhat telling that even anti-nicotine advocacy groups rarely mention the risk of cancer for smokeless tobacco products in their publications.
I doubt this was part of the curriculum, but in fitness classes at school we were told that breathing through your nose with your tongue pressed against the roof of your mouth helps develop your face/jaw and that breathing through your nose moistens the air and helps filter it. We were also told that it's not necessary to breath through your mouth when you're out of breath as you won't get or don't need more oxygen and that you risk hyperventilating this way, instead we were told that you should breath using your diaphragm to help mix the air in the lungs and that you should hold the breath for about as long as you inhale/exhale if you can help it. This sort of breathing exercise seems pretty common in any fitness/exercise related guide I've seen too.
As far as other countries/cultures go, any country that has a strong yoga/meditative culture likely considers breathing through your mouth to be bad too, but this is just speculation on my part. Pranayama is thousands of years old for instance and is primarily concerned with controlling and reducing your breathing, which is hard to do if you're not breathing through the nose.
Velvia 50 might resolve 160 lines/mm (I'm not sure if this is line pairs/mm or lines/mm) but that's at a contrast ratio of 1000:1, for a contrast ratio of 1.6:1 (more typical for normal shooting conditions) you're down to 80 lines/mm which is 22.1 MP, and that's for just the film stock under optimal conditions. When you factor in real life shooting conditions like the lens MTF charts, the aperture you were shooting at, whether you were shooting on a stable tripod, dust, grain, noise, etc, that number only goes down.
Conventional wisdom has been that you can get good results scanning colour film at 6-12MP, and this tracks with the results people got when they started comparing the first DSLRs to 35mm film - something like the full frame 11MP Canon EOS-1DS from 20 years ago with a mere 25 line pairs/mm (including losses from the Bayer and AA filters) compares favourably(*) to medium format film, with 6-8MP DX format DSLRs from the same era comparing favourably to 35mm. B&W film can be scanned at a higher resolution but still, 87MP is a theoretical maximum not a practical one.
https://github.com/RadeonOpenCompute/ROCm/issues/1714#issuec...