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April 2

MUSIC theory: a scale not listed on wiki

Hi, what the name of this octaphonic scale? unfortunately "bebop" scales put the chromatism on III, or V or VII, not on the VI! :(

C D Eb F G Ab A Bb C

(never G# !) (the "altered"/a bit foreign/augmented note is: A). (NO "c melodic minor descending" because we go DOWN on the 6# = A, and we go UP on the 6 = Ab). (less important degrees are: D and G). that is all what I can say. thanks a lot. — Preceding unsigned comment added by Vastymedoisa (talk • contribs) 02:22, 2 April 2022 (UTC)[reply]

If the scale is different ascending and descending, like the melodic minor scale, why isn't this a heptatonic instead of octatonic scale? Ascending, using A♭ instead of A, it seems to coincide with C natural minor. If we analyze the descending scale as the juxtaposition of two tetrachords as in Tetrachord § Romantic era, we get 2 1 2 : 2 : 2 1 2 or minor + minor, a combination that is not listed. Are there somewhat notable compositions that use this scale? If it is not really used, you cannot expect it to have been named. If you need a name, you might consider calling it the minor minor scale. --Lambiam 10:24, 2 April 2022 (UTC)[reply]

Hi, thank you very very much for your detailed reply, much appreciated! Even if it will be a too long name we could call it: "do natural minor ascending and do dorian descending" ? not "do natural minor ADD 6# " because ADD is employed in chords only, not for scales. Little addendum: a quartal chord mib-lab-reb-solb; can we name it "MIb min 11" ? (since it is a minor chord we never could mistake it as an "Eb SUS" = Db/Eb ).thanks a lot dear Lambiam! best regards. PS: I never receive email notifications about replies :( Vastymedoisa (talk) 13:02, 2 April 2022 (UTC)[reply]

I would indicate this as C minor (or perhaps C-Aeolian) with an added #13. C D Eb F G Ab Bb is already C-Minor. The 13th = the 6th, so adding a A is like adding a #6, or #13. --Jayron 32 12:21, 4 April 2022 (UTC)[reply]

Agri tech, robots, and cannabis

Is anyone, anywhere, using agricultural robots to grow cannabis, either indoor or outdoor? My guess is that they are not, because the technology is still under development. I remember seeing an ad for a company in California several years ago that had a working prototype for an agricultural robot that could grow herbs indoors. The company is called Iron Ox, and appears to be producing viable products for sale at Whole Foods. Is anyone using this tech for cannabis?

Thinking about it further, it seems like an interesting problem to be solved. Obviously, the water, nutrients, planting, lighting, temperature, humidity, and CO2 can be automated with ease, but the hard problem involves the targeted trimming and cutting,and cleaning up the plant material, particularly in the late flowering and harvest stages. I know there is an industrial machine in wide usage that processes and trims the flowers, but I’m curious if anyone has attempted automating the sea of green process (which appears to be standardized at this point) for example, in its entire growth and flower phase. Viriditas (talk) 09:07, 2 April 2022 (UTC)[reply]

A company called Iunu provide robots to "growers in the cannabis, floriculture, and vine markets". I don't know how much of the work their robots do: perhaps they're only for harvesting the plants. Card Zero (talk) 11:50, 2 April 2022 (UTC)[reply]

Video about scrolling message on metro train

Regarding my earlier question about the perceived leaning of scrolling text on a metro train, I shot a short video of the dot matrix display and uploaded it to Commons. It looks like the actual physical dots stay perfectly orthogonal the whole time, but they don't scroll all at the same time, the dots on the top scroll first and the dots at the bottom scroll a short while later. Could simply this explain why I perceive the text as leaning to the right? Note that what appears on the video is almost, but not exactly, what I see. On the video the text can be seen as orthogonal but with different parts scrolling different phases, whereas I see it with the horizontal lines perfectly horizontal but with the vertical lines leaning slightly to the left, not even conforming to the orthogonal pattern of the dots. JIP | Talk 13:54, 2 April 2022 (UTC)[reply]

Thank you for this glimpse of the beauty of Finland. Are you mixing up left and right? You say "leaning to the right" and then "leaning slightly to the left". It appears to be leaning to the left (often even when the video is paused) which is coherent with the upper scanlines scrolling left before the lower scanlines. Yes, this creates the illusion of leaning vertical lines, although the distinction you're making "not even conforming to the orthogonal ..." puzzles me. ITALIC TEXT, especially in the old days before anti-aliasing, uses orthogonal pixels to give the impression of leaning vertical lines. I know the pixels on this sign are large, and spaced far apart, but when the text itself is moving, and you are reading it (and hence interpreting it as symbols made from lines), do you expect to be able to distinguish individual pixels? Somebody linked to persistence of vision previously. Pareidolia is also relevant. Card Zero (talk) 14:29, 2 April 2022 (UTC)[reply]

I meant "leaning to the left". "Leaning to the right" was a typo. I know that it is actually impossible for the vertical lines to be non-orthogonal, but that's what I see them as. So far it all points to persistence of vision being the reason. JIP | Talk 15:03, 2 April 2022 (UTC)[reply]

Yes, but also consider pareidolia, and the idea of an ambiguous image. MC Escher's "Convex and Concave" is a particularly good example: is the central decoration a hollow in a floor, or a protrusion from a ceiling? The reason this is relevant is that what you see is what you're looking for, to some extent, and in this context you're looking for lines. Possibly if you concentrate, with the right sort of zen-like mindset, or the help of unusual mushrooms, you might see the individual dots and cease interpreting them as lines. Card Zero (talk) 15:38, 2 April 2022 (UTC)[reply]

There appear to be two processes operating simultaneously, at a rate of about 50 Hz. One is that all dots are simultaneously shifted one position to the left. If that was the only process, the moving characters would not be slanted in comparison to the still characters. But then, also one whole row of dots is refreshed. There are eight rows, and the refreshing proceeds bottom to top. For reasons I am unable to scrute, the refreshed row overwrites the old row, but shifted one position to the right – not where the row is now, but where it was one tick ago. So in the movement to the left, lower already refreshed rows lag with respect to the higher old rows. In the video you can see the refreshing as a slightly dimmed band moving upwards, repeating at about 6 Hz. Since, on the average, each next row is one eighth dot to the right of the one just above it, the characters look slanted to the left with an angle of 7°. --Lambiam 17:05, 2 April 2022 (UTC)[reply]

The fact that the refreshing can be perceived in the video may be the result of interference between the frame rate (24fps) and the 50 Hz process; see wagon-wheel effect. 50 Hz is not above the flicker fusion rate, but good enough to experience the overall right-to-left motion as smooth. --Lambiam 17:18, 2 April 2022 (UTC)[reply]

I don't have any further explanation or speculation to add, but I'll just mention, in clarification of my comments on JIP's previous question, that in the similar displays in train carriages that I have seen in the UK, the letters (usually rendered in red) appear to lean to the right, not left: presumably this just means that these particular displays refresh in the opposite direction.

To answer a point raised by Card Zero, If I look at the display as a whole, my eyes naturally follow the "movement" and I perceive moving letters made up of (quite visible) dots, but if I deliberately concentrate on a particular part of the display, I can see it as a number of unmoving dots flashing on and off. Lambian's dimmed "refresh band" visible in the video is not visible to the (at least my) naked eye. {The poster formerly known as 87.81.230.195} 90.209.123.235 (talk) 18:12, 2 April 2022 (UTC)[reply]

Here is an abandoned patent application (abandoned because of prior art?) for a method of scrolling text on a multiplexed LED matrix display in which the LEDs are turned on and off row by row. Paragraph [0006] explains why this results in slanted text, called a "spatial artifact" in [0007]. I have some problem understanding the explanation (what precisely is meant by "the eye's gaze point has advanced one-seventh of the way toward the next column to the left"?). The fact that in the video the whole text appears to move left by almost a whole column at a time may well be an artifact, though, of the video's frame rate being lower than the rewrite rate of the display, and not of some dual process I imagined. --Lambiam 19:28, 2 April 2022 (UTC)[reply]

Precisely. The video is not much more use than a series of still images, since so much updating of the display takes place between frames. In fact the display works through nearly all its scanlines (working from the discontinuity down to the bottom and then starting again from the top) between video frames, but since it doesn't manage all of them in that time-span, the discontinuity moves upward from one frame to the next. Card Zero (talk) 19:36, 2 April 2022 (UTC)[reply]