Indeed, a 10%-20% difference is so much that airliners would sell their grandmother (if they had one) for a leap like that. A 2% improvement is considered significant and is a massive economic incentive, even more so these days for long-haul flights which are now in some cases 50% longer due to conflicts, and at times extreme price hikes for jet fuel.
(This applies a bit less to military engines though, where performance is a more important factor. Fuel efficiency is still important though)
Ah, 20kHz and CRT flybacks.. when I was a child I could of course hear that (in Europe that would be 15625 Hz), when I studied electronics and TV repair we could all hear that, and because we had the equipment we "tested" what we could hear using a function generator. The limit for conscious hearing for me was somewhere around 17kHz. Or not 18kHz for sure.
But I think I lost the ability to hear the flyback not long after I passed twenty. The world turned silent as far as that's concerned (before, you could hear it anywhere and everywhere, in shops, homes, some workplaces..)
The "20kHz" thing is kind of a myth for most people, at least that's what it looked to me after all the testing we did at school. I think it can influence what you hear, somehow, but in any case it's for very young people.
> Most people have no idea how much their high frequency hearing degrades as they age because it plays approximately no role in your life, but it's real, dramatic, and as far as I know happens to everyone.
I agree completely. I recall some discussions a long time ago on RMMGA (Usenet: rec.music.makers.guitar.acoustic) where some distinguished and experienced, but middle-aged guitarists got practically angry when a young guy described the sound of a certain type of newly-introduced strings "harsh" and "like fingernails on a blackboard" when used on a particular guitar.
The difference was, of course, that what the young guy could hear is something which stopped existing at least when you had passed 30.. I was at an age where I too couldn't hear that kind of sound from strings, but it was still not that long ago and I remembered and had noticed the difference, i.e. that I could not hear what I could hear before. For example the huge difference between fresh strings and week-old strings (and that fact has, over the decades, saved me tons of money which I would otherwise have spent on replacing strings all the time..)
It all depends on the country and the local rules, which can also change from year to year. Attendence didn't matter much, if at all, in my day, but right now it matters. Extremely so. Student's couldn't, until this year (when this was finally revised) even visit the school nurse without getting a "no attendance", which would count negatively with respect to the mandatory attendance requirement for advancing further. And even for receiving the common stipend.
In college I one year had a physics teacher who refused to believe that you could hear the harmonics of a guitar string simply by lightly touching the string at the right place, e.g. in the middle (12th fret) to hear the octave. Nothing could convince him that this was possible.
That year was when several of us spent a good part of the week bowling in a nearby bowling hall, either because we didn't have to take the class (the curriculum was years behind what we had already done before college), or the teachers were so incompetent that there was no point attending.
Fortunately the other educational years (everything after middle school, that year excepted) were great though.
I ran into issues early on, I used (and needed) an 'expect' script to run as part of a daemon startup, and that just didn't work with systemd. And then on another computer 'udev' spiked to 100% CPU after Debian switched to systemd, and I never managed to find out what on earth triggered that. I didn't want to spend a lot of time to solve these things, so I simply switched all my computers from Debian to Devuan (aka Debian without systemd) and I've had zero problems with that switch, which happened years ago.
The "Limited Express" logo existed only until the railway was privatized, if I read the article correctly. In any case I haven't noticed it, and you know when a train is a limited express - it's right there on the board announcing incoming trains (and if it's your train then you already have a limited express ticket and you know the exact time it arrives). And, finally, there's an audio announcement which says that it's a limited express. But I'll look for the logo the next time I'm at the station, it would be interesting if it's still there. I actually hope so.
That "L" wasn't used in my European country until recently, and when I saw it the first time I didn't really get what it was supposed to mean. I was guessing that it could be something indicating that the driver didn't have a license and was practicing with someone (something which you can do legally, if the other person is above 25 and has had a license for multiple years, and in areas which are not trafically complicated). But I was thinking it could also mean that the driver had just got the license, but that sounded strange to me as well.. having never heard about any license divisive system being introduced.
I realize I in fact still do not know what the "L" is supposed to mean, in my country.
Japanese rice is not commonly produced in other countries. And even where they do, the rice is not the same. I eat rice made inside Japan and made outside of Japan, and the latter is a poor substitute.
I specifically mentioned families where the economy is not a burden, and they still don't want many children. Very few will want more than two. Please note that in my country at least, as long as the economy is good enough that there aren't any real problems living, then it doesn't matter if it costs more with more children. That is not the reason.
I didn't say that 1500 years ago is a short timeframe. I'm saying that if you look at short timeframes like a decade or a generation or two it may look like there's not much migration going on. But stretch that a bit, and you'll see the changes. It's like a slow-moving river. Always moving, if you yourself move your viewpoint back a little.
In what way? I included England just because those particular periods are well-known.
If you look at ALL of Europe's history, all up to recent times, there's been constant movements and migrations. People with different backgrounds, moving around, a lot of movement came as trade increased (and, as it has lately been found, there was much more trade even 3k years ago than anyone had previously anticipated). If you look at a snapshot of time it looks pretty static, but let your time-tick be generations and you see constant changes.
If you have a way to secure rice production, please let us know. Or did you mean to abandon rice because it's too labor intensive? There's a reason for subsidies, just as there are reasons for agricultural support in my home country - without it there would be no agriculture. And, without going into details, that would be a disaster.
It only looks like that because you're looking over a relatively short timeframe. Start looking over more than a generation and things will look different. I just have to check my father's ancestry research to see that - his notes includes a lot of extra information not directly related to my forefathers, and yes people moved. That a lot of people move in, historically, an instant, is something that doesn't happen always, but it has happened again and again over time. The net result is in any case that anyone country is, when you look back, always a product of its immigration. And it's still a country which you would attribute national culture to. The culture isn't frozen if you look over a large enough timeframe, and I for one am happy for that - my boring childhood town isn't that way anymore: boring.
Rice fields, around here at least. That's always been very labor intensive. They do use tractors to do some of it, but around the periphery of every field it's still done manually. Rice fields are very different from wheat production.
In my country strawberries are picked manually. There's yet no mechanical solution which can do what humans can, with respect to quality and more. And that's already a problem, without seasonal immigration there will be no strawberries on the market, simple as that. There are many other kind of work which still requires a young healthy work force.
What I'm asking is "..dared to try what?". What, excactly, would you offer? As I mentioned in another comment, those families in my own country which a) do not have any economical worries, and b) have great family leave support from work, i.e. no career problems whatsoever, and c) even more that I don't list here, they DO NOT WANT more than two children anyway. Because it feels fine with two. And then there's a problem, because that's not enough - there are a lot of singles out there, and most of them don't produce any children. You need more than two children per family, on average, to keep up the birthrate vs the death rate.
So, what is the solution that nobody has dared to try?
>They’ll find it easy to keep their homogenous culture and shared traditional values.
That idea is a fallacy. It has never been true. All of Europe was always a melting pot for people from everywhere. Over the centuries people kept moving, immigrating and emigrating. England.. Britons, Celts, Anglo-Saxxon, Norse, Normans (which were themselves originally immigrants). And my own country? Surnames from everywhere. 40% of my language's vocabulary came from immigrants. Is that a problem? I most certainly can't see any.
The idea about 'homogenous culture and shared traditional values' is as true as looking at a flower for five minutes and then claiming that "nah, it doesn't grow, it's frozen".
It is not as simple as that. In my country giving birth is free. And you get economic support for every child. For most people it's still an economic burden to some extent, but for the majority it's not something which blocks them from having children. It's more that most families I know are content with having two children. It feels fine to them. But that's the families that do have children. 25% of men in my country never have children. It's not enough. A lot of families need to produce 3 children, and better if there are some with four.. and most people simply don't want that. And that's for the most part not a question of economy.
The worldometer statistics site doesn't fully agree with that, the Guardian reports that the rate went from 0.75 to 0.80, while worldometer states that the 2026 rate will probably end up at 0.76. At best this has kind of stopped dropping, but it is any case catastrophically low (and way worse than Japan)
Look back a few hundred years and you'll find that the country you grew up in, in Europe, was constantly in that situation. People moved a lot back then too. And the countries are today.. the countries. It'll be fine.
(This applies a bit less to military engines though, where performance is a more important factor. Fuel efficiency is still important though)