Today I Learned

[Stavros Kiri]

I learned that to remove the n right-most (leftmost) characters in an Excel (Workbook) file, where data is stored in column C, we can use:

Edit: LEFT( C:C, LEN(C:C)-N)

For example, to remove the 6 right-most characters ( which is what I did) from column B in a workbook, we use:

LEFT( B:B, LEN(B:B)-6)

Sounds counterintuitive to use LEFT here, but I assume it means the last n characters starting left.

At any rate, I used it to remove units from a file in order to analyze the data; so that the workbook contained only numbers.

Also , learned the leftmost r' used in the pd.read_ function is used to escape the slashes in strings.

Hopefully also finally internalized, after so many years and mistakes, that the 4extension for my files is .xlsx and not .xlsx. Computers are "autistic" .

See what life is teaching you?! You must feel a lot better now! ...

 

[strangerep]

TIL... the word "braggadocio", after a journalist used the word to describe a recent press conference.

 

[jack action]

TIL the word 'innervate' ... which is not the same as 'enervate'!

 

[Buzz Bloom]

Today I learned two new-to-me facts about chemistry nomenclature.

https://www.physicsforums.com/threads/why-is-hcl-called-hydrogen-chloride-by-iupac-naming.996456/​

Post #8.​

 

[Keith_McClary]

https://www.physicsforums.com/threads/why-is-hcl-called-hydrogen-chloride-by-iupac-naming.996456/
Post #8

Today you learned that you can link directly to the post by using the "Share this post" icon:
https://www.physicsforums.com/threa...chloride-by-iupac-naming.996456/#post-6421961

 

[Drakkith]

Today I learned that as late as the 1970's almost the entire world's supply of light bulbs was produced by just 15 machines scattered across the globe: https://blog.cmog.org/2017/01/27/the-machine-that-lit-up-the-world/

 

[fresh_42]

TIL something about SR which is actually useful here on PF:

Travelling time to Andromeda with 1g acceleration and deceleration (Einstein): 28 years boardtime
Travelling time to Andromeda with 1g acceleration and deceleration without the c constraint (Newton): 2,800 years boardtime
Reason why it won't work either way: CMB will work as resistor and additional energy meant for acceleration will be turned into particle production instead and arbitrarily close to c will be physically impossible, regardless which engine we constructed.

These easy arguments could shortcut many fruitless discussions on space travel.

 

[Astronuc]

This week I learned that carbon dating a fossilized life form is dependent on the diet of the life form.

Carbon from terrestrial plants, and herbivores consumed by carivores/omnivores, has 'younger' carbon than fish in the ocean. People with marine diets have a different proportion of carbon than people eating meat and plants from land.

https://www.pbs.org/wgbh/nova/video/why-did-these-vikings-bones-appear-older-than-they-are/

I actually heard about it on a program related to archeological investigations of peoples in the Arctic region in northern Canada, Greenland, Iceland and Norway. The program was exploring the potential interactions between Norse Vikings and so-called Dorset peoples.

https://en.wikipedia.org/wiki/Dorset_culture
https://www.historymuseum.ca/cmc/exhibitions/archeo/paleoesq/ped01eng.html

 

[BWV]

you can safely disregard anything that comes after the word ‘may’ in a popular science headline

 

[Keith_McClary]

you can safely disregard anything that comes after the word ‘may’ in a popular science headline

And anything ending in "?".

 

[Stavros Kiri]

CMB

+ also perhaps cosmic radiation (wherever in space it exists), scattered particles, small rocks and interstellar dust etc. ...
In other words, not an empty space, as we would ideally imagine ... Thus it would require very advanced 'Shields' ... (with such velocities) etc.

 

[jtbell]

Today I learned about the world's first underwater roundabout. It's at the junction of a Y-shaped undersea tunnel which will open later this month in the Faroe Islands. You can read about it (with map and pictures) in English and in Faroese.

 

[Jarvis323]

I learned that (according a study) our "stuff" (not including our trash) now outweighs all life on Earth. And apparently our plastic stuff alone outweighs all animal life on Earth.

https://www.nature.com/articles/s41...45_deeplink_PID100044684&utm_content=deeplink

 

[BillTre]

I learned that (according a study) our "stuff" (not including our trash) now outweighs all life on Earth. And apparently our plastic stuff alone outweighs all animal life on Earth.

https://www.nature.com/articles/s41...45_deeplink_PID100044684&utm_content=deeplink

Here is a Science mag news article on this.

 

[BillTre]

TIL there are fun barcodes:

 

[BillTre]

TIL that:
Pandemic lockdown has lead to more people gardening in Britain.
More people digging around in their gardens has new archeological discoveries.

Gardeners in Hampshire, a county in southeast England, were weeding their yard in April when they found 63 gold coins and one silver coin from King Henry VIII’s reign in the 16th century, with four of the coins inscribed with the initials of the king’s wives Catherine of Aragon, Anne Boleyn and Jane Seymour.

The archaeological find was one of more than 47,000 in England and Wales that were reported this year, amid an increase in backyard gardening during Coronavirus lockdowns, the British Museum said on Wednesday.

 

[Ibix]

TIL there are fun barcodes:
View attachment 274122

View attachment 274124

View attachment 274125

View attachment 274126

When my son was little we had a story book about a chameleon, one of those cardboard ones with wheels and flaps, so the chameleon changed colour. The last page had a wheel embeddedin it, and the back cover had the barcode with a chameleon-shaped cutout above. When you turned the wheel the chameleon would shift from green to having barcode stripes.

 

[fresh_42]

When my son was little we had a story book about a chameleon, one of those cardboard ones with wheels and flaps, so the chameleon changed colour. The last page had a wheel embeddedin it, and the back cover had the barcode with a chameleon-shaped cutout above. When you turned the wheel the chameleon would shift from green to having barcode stripes.

What you did not know: It also changed while in store from £ 7.95 to £ 14.95.

 

[mfb]

Today I learned about the world's first underwater roundabout. It's at the junction of a Y-shaped undersea tunnel which will open later this month in the Faroe Islands. You can read about it (with map and pictures) in English and in Faroese.

To illustrate the use of the tunnel:

 

[dlgoff]

Today I learned about the world's first underwater roundabout.

 

[DaveC426913]

And anything ending in "?".

I've heard a generalization that applies to any headline.

If a headline ends in a question mark - the answer to the question asked - is 'no'.

 

[BillTre]

Here is a XKCD 2020 election map.
I am posting this for data visualization purposes, not political purposes!

The point is that this map shows:

• how the people in states voted, while
• maintaining the geographical relationships of a normal map,
• as well as the relative proportions of the voters in each state.

Not an easy combination to achieve.

 

[Jonathan Scott]

Here is a XKCD 2020 election map.

I'm often in awe of the huge amount of time and effort that Randall Munroe must have put into some of his xkcd postings.

 

[DaveC426913]

I was impressed at this graph too. And admire RM for his tenaciousness.

Though I was/am at a bit of a loss as to what useful knowledge can be gleaned from this visualization.

 

[Keith_McClary]

useful knowledge

Maybe in the mouseover comment?

There are more Trump voters in California than Texas, more Biden voters in Texas than New York, more Trump voters in New York than Ohio, more Biden voters in Ohio than Massachusetts, more Trump voters in Massachusetts than Mississippi, and more Biden voters in Mississippi than Vermont.

 

[jack action]

I was impressed at this graph too. And admire RM for his tenaciousness.

Though I was/am at a bit of a loss as to what useful knowledge can be gleaned from this visualization.

What I learned with this map when I first saw it is how well-mixed are the republicans and democrats throughout the country. I'm so used to see the red-center-with-blue-borders-map that gives the impression that the USA is 3 different countries isolated from each other. Clearly, there are no real 'red' or 'blue' states as I could of imagined.

 

[Ibix]

What I learned with this map when I first saw it is how well-mixed are the republicans and democrats throughout the country. I'm so used to see the red-center-with-blue-borders-map that gives the impression that the USA is 3 different countries isolated from each other. Clearly, there are no real 'red' or 'blue' states as I could of imagined.

I recall a map of the states coloured by popular vote, from the 2004 election I think. Instead of red/blue, everywhere was redder or bluer shades of purple. Can't now find it, but here is a county-level map of the 2016 election, which makes much of the same point.

 

[Ivan Seeking]

I've been learning all about yeast. My specialty is process control with a heavy emphasis on process. As a result, I am constantly learning about processes and technologies new to me. This is perhaps the best part of what I do. From launching rockets to putting the smile on the Pepperidge Farms Goldfish, from being held hostage to being treated like royalty, I have been lucky enough to see and do many amazing things. But today my world is all about yeast. And like most everything else I learn about, sure enough, yeast is interesting!

There is nothing more rewarding than solving problems that have stumped the experts. And I can do that because I studied physics.

 

[Janus]

TIL*: How to use Blender to render "millions" of objects like in this render I did of piles and piles of bricks:

This was just a test of the method, and could use some refinement particularly in the background and brick texturing.
The basic method is this:
Create a large number of "bricks"(500+) This can be done by duplicating a brick**, then selecting both, duplicating them... Making an array of bricks in a layer. Make duplicates of the layers stacked on top of each other with space between each layer, with a bit of random rotation and placement. Create a large plane some distance under them.

Run the physics engine, allowing the bricks to fall onto the plane creating a pile of bricks.
Put your camera directly above the pile, looking straight down and give it a square aspect ratio, making sure that only bricks are in the frame.
Render the scene and save the image.
Now you are going render the same scene, but time using something called the "mist pass". The upshot is that this produces a grayscale image that is a relief map of the bricks. Save this image.
Now you need to take both images an do some editing. Each of these imaged are going to be used in a "tiled" material (basically repeating the same image over and over). The problem with the images as they are is that you will see very distinct seams where tiles meet. Thus you need to make them "seamless". Without going into details, this means making where the tiles meet "flow" into each other. How you do this depends on what type of image editor you have.

Now, you start a new scene, create a new plane and scale it up. You create a tiled texture (with this image I went 10 x10) using your first image of bricks, which "paints" a ten by ten grid of images on your plane.
You then take the mist pass image, tile it to the same scale and use it to perform a displacement on the plane (again there are some additional steps needed to make this work that I am skipping here).
This gives you a plane with not only the image of the bricks on it, but also the bumpiness effect of the bricks being real objects.
You now add another larger scale displacement to the plane to create the "hills"
One last step:
At this point, things look okay as long as you don't get too close to the plane. If you do, it becomes quite obvious that something isn't quite kosher.
So here's how to fix that: make a new somewhat smaller plane a put it in the foreground of your scene. Sculpt it into a hill shape. Do like we did before, make a bunch of bricks and let them fall onto the 'hill". This produces a "pile" of brick objects in the foreground and helps to complete the effect.

*I actually did this yesterday, but didn't finish until quite late.
** Both the brick and the later plane have to be assigned as being "rigid bodies" in order for the the bricks to fall and interact with the plane.

 

[epenguin]

You can have practical experience of something yet never explicitly formulate it as a generalisation. Today I learned that I knew one such but didn't know I knew it. It is called, among other names, Brandolini's principle: https://en.wikipedia.org/wiki/Brandolini's_law