Things you don't need to know...

More fun with mathematics. Yay!

In Algebra/Number theory, many numbers are considered "interesting" due to their properties.

For instance (only considering non-negative integers, and I'm only mentioning a few of their properties):
  • 0 is the unit under addition: a+0=0
  • 1 is the unit under multiplication: a*1=a
  • 2 is the first prime, and also the only even prime number (which makes it a very "odd" prime).
  • 3 is the first Mersenne prime. Mersenne prime numbers follows the formula 2^n-1, where n is a prime number, but not all numbers of that form is prime (most are not). Mersenne primes are interesting for several reasons. There is for instance a relation between Mersenne primes and perfect numbers (see below). If 2^n-1 is prime, then (2^n-1)*2^(n-1) is a perfect number. Mersenne primes are often used in pseudo-random number generators.
  • 6 is the first perfect number. A perfect number is a number which equals the sum of its factors - excluding the number itself, but including 1. 6=1+2+3. The next perfect number is 28 (1+2+4+7+14).
  • 4 is the smallest composite number, a number which can be factorized.
  • 17 is the sum of the first 4 prime numbers (2,3,5,7).
  • 30 is the smallest sphenic number (a product of 3 distinct primes)
  • 42 is the 2nd sphenic number, and the 7th pronic number (numbers which are the product of two consecutive integers).
  • 43252003274489856000 is the total number of possible configuration of the Rubic's cube
  • 2^74207281 − 1 (a 22 million digit number) is (January 2016) the largest known prime number, and also the 49th Mersenne prime. BTW: While we know there is an infinite number of primes, we don't know if the number of Mersenne primes is infinite. There are good reasons to believe that there are infinitely many, but it hasn't been proven.
  • (2^74207281 − 1)*2^74207280 is the 49th and largest known perfect numer (Jan 2016). It contains 44677235 digits.
So, are all integers interesting? In the "Penguin Dictionary of Numbers", 39 was listed as an uninteresting number in early editions of the book, but not now. So?

The question is of course meaningless, since "interesting" is a highly subjective concept. People who find math boring will probably find most numbers uninteresting. And I who really love math tend to find every number I come across interesting. Even the uninteresting ones. But we're here for the fun of it, so let's take a closer look and prove it.

Let's assume that the answer is no, which means that there is a set of integers which have no interesting properties. By the well ordered principle (which says that every non empty set of integers contain a smallest element), there is a smallest uninteresting number. But surely, being the first uninteresting number must be interesting. Which leads to a contradiction, and we may draw the conclusion that yes, all numbers are interesting.

While proof by contradiction is a valid approach, as I said, the question is meaningless. BUT I FIND IT FUNNY!!!!!

This, btw, is called the "Interesting Number Paradox", and of course there is a piece about it on Wikipedia: https://en.wikipedia.org/wiki/Interesting_number_paradox.

pibbur who thinks he himself must be interesting, because if he wasn't, he would be the only uninteresting one, thus making him interesting.

PS. We could reformulate the concept of being an interesting number in a more objective way, by saying that an uninteresting number is a number not listed, for instance (According to Wikipedia) in an entry of the "On-Line Encyclopedia of Integer Sequences" (https://oeis.org/). However, numbers classified by such definitions tend to change. PS.
 
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http://www.bbc.com/future/story/20170428-i-have-a-strange-second-sight

A blind woman describes how she learnt she had one of the world’s most intriguing senses.
...
A handful of people in the world have “blindsight”: they are blind, but their non-conscious brain can still sense their surroundings.
...
“If I was to throw a ping pong ball at Milina’s head, she would probably raise her arm and duck out of the way, even before she had any awareness of it,” says Jody Culham, a scientist who has scanned Cunning’s brain.
Click to expand...

You don't need to know that Daredevil was not based on fiction.
 
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http://edition.cnn.com/2017/05/04/health/babies-screen-time-speech-delays-study/

The study found that the more time children between the ages of six months and two years spent using handheld screens such as smartphones, tablets and electronic games, the more likely they were to experience speech delays.
...
Twenty percent of the children spent an average of 28 minutes a day using screens, the study found. Every 30-minute increase in daily screen time was linked to a 49% increased risk of what the researchers call expressive speech delay, which is using sounds and words.
Click to expand...

You don't need to know that... Yea. Me vs Nintendo.

.....

http://www.ibtimes.co.uk/scientists-reveal-first-ever-map-bipolar-brain-1619539

Bipolar disorder affects up to three in 100 people and can be a debilitating condition to live with. The condition has been studied for decades but there have been very few conclusive findings about how it affects the structure of someone's brain.
...
A landmark study has now found that the brain's grey matter – made up of the bodies of nerve cells – is thinner in several regions of the brains of people with bipolar. The difference is the greatest in the brain regions responsible for inhibition and motivation.
Click to expand...

You don't need to know that not everyone diagnosed as bipolar is actually bipolar, thanks to this study now we'll know for sure.
 
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Thrasher said:
What makes a perfect grilled cheese sandwich?

http://www.latimes.com/food/dailydish/la-dd-grilled-cheese-truck-dave-danhi-20170510-htmlstory.html
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Rats! I have already planned dinner for the wife and me (Avocado Soup).

But: Here's a follow-up. The term "sandwich" comes from the name of the 18th century British nobleman John Montagu, 4th Earl of Sandwich. He often ordered meat tucked between two pieces of bread, allegedly because it "allowed him to continue playing cards, particularly cribbage, while eating, without using a fork, and without getting his cards greasy" (Wikipedia). And his friends began ordering "the same as Sandwich".

Observe that while the connection between Sandwich and sandwiches is valid, the connection to playing cards is probably an unsubstantiated rumour.

pibbur who may prepare sandwiches tomorrow.

PS. The Norwegian word for "sandwich" is "smørbrød", but we don't restrict the name to the two-piece-of-bread-with-something-in-between variant. DS.

PPS: Here's a poem about sandwiches, written by the 16th century Norwegian poet Johan Herman Wessel:

At Smørrebrød er ikke Mad,
Og Kierlighed er ikke Had,
Det er for Tiden hvad jeg veed
Om Smørrebrød og Kierlighed.

For you Nordic-language-challenged (sorry about the missing rhymes):
That sandwiches are not food
And love is not hate
That's what I at the moment know
About sandwiches and love.

DS.
 
Super glue!! According to many, one of the most important inventions of the 20th century. I have to admit I am a bit in doubt. After all, said century brought us airplanes, antibiotics, moon rockets, vinca alkaloids, tv and reality tv, computers, JRPGS and the MRI thingy. PET scanners. Putting super glue in the same category seems a bit pretentious. Still, super glue (and velcro) is a very important part of my life (velcro for preventing things from falling down, super glue for fixing the things that do)

BTW: "Super Glue" is a brand name, but like other brand names it has been generalized by the masses to meaning any implementation of said type of glue.

Chemically super glues are cyanoacrylates. They were discovered by accident in the early 1940's by a team searching for suitable materials to use in gun sights. Being too sticky for the purpose, they became forgotten. Rediscovered in '51, the commercial potential was recognized, and as they say, the rest is history.

By googling I've found several interesting uses:
  1. As a glue (surprise, surprise)
  2. For protecting fingers of string instrumentalists
  3. For closing wounds, mending bone fractures (veterinary medicine). There is evidence that superglue may be more efficient, with reduced risk of infection, than stitches. Which is kind of bad, as doctors in general like suturing wounds (one of the very few things I really miss). Observe that this requires sterile preparations, obviously costing at least 10 times more than the common Loctite formula.
  4. As a "nail glue" for artificial nail enhancements
  5. As eye drops. Not recommended.
  6. Accidentally gluing body parts together.
  7. Deliberately gluing body parts together (superglue revenge). Lots of urban legends here, but it's usually about gluing body parts of your ex to other body parts of your ex. For male victims, one of said body parts is rather obvious.
  8. Starting a fire. Soak a ball of cotton in superglue and, due to the heat generated when hardening, it can ignite. A bit MacGyverish, but useful to know when starting a fire is required, and the only equipment you brought with you was … cotton and superglue.

Never use superglue in close approximation to your keyboard.

pibbur who has bought lots of super glue bottles, and at the moment knows the location of two, one of them all dried up
 
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https://www.theatlantic.com/magazine/archive/2017/06/when-your-child-is-a-psychopath/524502/

At 11, Samantha is just over 5 feet tall and has wavy black hair and a steady gaze. She flashes a smile when I ask about her favorite subject (history), and grimaces when I ask about her least favorite (math). She seems poised and cheerful, a normal preteen. But when we steer into uncomfortable territory—the events that led her to this juvenile-treatment facility nearly 2,000 miles from her family—Samantha hesitates and looks down at her hands. “I wanted the whole world to myself,” she says. “So I made a whole entire book about how to hurt people.”

Starting at age 6, Samantha began drawing pictures of murder weapons: a knife, a bow and arrow, chemicals for poisoning, a plastic bag for suffocating. She tells me that she pretended to kill her stuffed animals.

“You were practicing on your stuffed animals?,” I ask her.

She nods.

“How did you feel when you were doing that to your stuffed animals?”

“Happy.”

“Why did it make you feel happy?”

“Because I thought that someday I was going to end up doing it on somebody.”

“Did you ever try?”

Silence.

“I choked my little brother.”
Click to expand...

You don't need to know that until recently this was not considered as disorder probably because "The condition can go unnoticed because many children with these traits—who can be charming and smart enough to mimic social cues—are able to mask them.".
 
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Paweł Zadrozniak and his hardware orchestra. 64 floppy drives, 8 hard disks, , 2 scanners, main hub: Cover of the Imperial March.
 
https://www.technologyreview.com/s/607828/an-algorithm-summarizes-lengthy-text-surprisingly-well/

Who has time to read every article they see shared on Twitter or Facebook, or every document that’s relevant to their job? As information overload grows ever worse, computers may become our only hope for handling a growing deluge of documents. And it may become routine to rely on a machine to analyze and paraphrase articles, research papers, and other text for you.

An algorithm developed by researchers at Salesforce shows how computers may eventually take on the job of summarizing documents. It uses several machine-learning tricks to produce surprisingly coherent and accurate snippets of text from longer pieces. And while it isn’t yet as good as a person, it hints at how condensing text could eventually become automated.
Click to expand...

While soon we won't need to read avoid dart's walls of text, you don't need to know there is still no software that'll automatically add "pay2win" and "scam" tags on certain products falsely advertised as videogames.
 
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I admit it: I'm not particularly fond of accordion music. Turns out, neither are chimps, evident from the following youtube video. (If you don't understand what's being said, it's due to insufficient understanding of the Norwegian language):


The Lindesnes Accordion Club was recording a video in a Norwegian zoo. The chimps behind them were not impressed, becoming more and more distressed until they started throwing rocks at the performers.

As I said, the video is in Norwegian, but you can FF to 1:50 for the real action.

pibbur who now is satisfied that accordion music is against nature.

PS. The musicians had to stop performing. DS.
 
Must either have been the guitar - or the wrong type of music.
I'd think something of a bumblebee would impress these chimps. I'm sure they've got taste - that or the buzzing sound of the following Rimsky-Korsakovs piece is more in line with nature. :)

 
One day I listened to a duo (Cello, Accordeon) performing that famous pieace by Bach ... I forgot its name ... But I'm sure everybody knows it ! On Accordeon !
 
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I hate Bach. :) Bach surely is against nature. ;)
I love cello though. The combination cello and accordion sounds interesting.
 
Toilet paper. Over or under? Toilet Paper Orientation

… I came across this when I read about Thimbleweed Park, which includes an option to switch the toilet paper orientation in the game's bathroom locations.

The answer must be "over", of course.
 
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A kangaroo is on the loose in Norway. Down south.
jdYvR98M4ZnrDoQe0Pb28Qgup_OH5R_YMuNyktQIQZQw


It ran off during feeding time (what did they give him?). Since it's from down under (the land with 72 species of animals, all of them deadly), I assume we should be frightened.

pibbur who will stay home for his 4 week long summer vacation.
 
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