What is the newest installment of 'Random Thoughts' on Physics Forums?

[Keith_McClary]

impracticality of lettuce as a gift to starving people

They are probably spending their money on cheap calories.

 

[Jarvis323]

They are probably spending their money on cheap calories.

True. I realize it is s nice gift. But I'm not about to start a fight famine with lettuce action group or anything.

 

[WWGD]

True. I realize it is s nice gift. But I'm not about to start a fight famine with lettuce action group or anything.

And they will likely not have refrigerators to keep it fresh, edible.

 

[WWGD]

Maybe one of these concentrated nutrient powders to be used with water instead.

 

[WWGD]

There is this singer Dio who's real name us Ronnie James Padavano, but changed it to 'Dio', which means God in Italian. Seems Ronnie James does not have major issues of self-esteem.

 

[WWGD]

More on Tutoring. They don't pay me enough:
Prove the sum of 2 Irrationals is not necessarily Irrational.
Me: Hint: 0 is not Irrational.
After an hour:
What does that mean?
Well, if a+b=0, what is the relation between a,b?
1 day after wards:
Can you just solve it for me?

 

[Keith_McClary]

They don't pay me enough

Who gets to figure out how much is owed?

 

[WWGD]

Who gets to figure out how much is owed?

Preagreed upon baby-sitting, er, tutoring fees. Edit: Sorry for being snippy.

 

[WWGD]

Hey Keith, whatever happened to the Montreal Expos team? Why aren't there any more baseball teams from Canada in MLB? EDIT: I thought you were Canadian and would know about it.

 

[WWGD]

Ouch. Some amateur Mathematician asked me to assign him an " Interesting Problem". I just
made one up and asked him to prove that there are infinitely many Fibonnaci primes. I just read
its still an open problem. And I don't have his contact, so I don't know howto tell him.

 

[Keith_McClary]

Montreal Expos

https://en.wikipedia.org/wiki/Washington_Nationals

 

[WWGD]

https://en.wikipedia.org/wiki/Washington_Nationals

Thanks. I thought you were our designated Canadian.

 

[Astronuc]

Do one's homework before investing!

The IPO of crypto exchange Coinbase on Wednesday has captivated fans of digital currency and investors as they speculate on the potential for a $100 billion valuation on the company.

But

"I think it's [Coinbase] worth closer to $5 billion or $10 billion as opposed to $100 billion," New Constructs CEO David Trainer tells Yahoo Finance.

https://finance.yahoo.com/news/coin...ion-not-100-billion-strategist-155726412.html
Besides the discrepancy in valuation, why is this a big deal.

Well, Coinbase is one of many companies incubated by IdeaLabs (and Bill Gross).
https://www.idealab.com/ (look under Our Companies), or
https://www.idealab.com/all_companies.php

Some have been very successful, others not so much.

I knew one of the VPs at eSolar (since left the company and now retired). They had a large project for concentrated solar power, Sierra SunTower. It didn't perform as expected and has been shutdown.
https://en.wikipedia.org/wiki/ESolar#Sierra_SunTower

A critic - http://guntherportfolio.com/2013/04...f-concentrating-solar-power-underperformance/

It's interesting that IdeaLabs (with Prime Movers Lab) has been supporting another solar power company, Heliogen, which would seem to be using similar, if not the same, technology.
https://heliogen.com/
https://www.primemoverslab.com/portfolio/

Both IdeaLabs and PrimeMovers Lab are supporting interesting companies.

 

[WWGD]

Not made up. This lady Jennifer Weir from Mad Tv married a guy with ladt name Dasz. They set up a company " Weir-Dasz Productions".

 

[Borg]

That seems strange.

 

[WWGD]

That seems strange.

Weir(d as ) anything I've heard.

 

[WWGD]

If my brother's daughter is called Denisse, should his upcoming son be called Denefew?*

*Denisse : The niece,
Denefew: The Nephew.

 

[fresh_42]

I'm rarely proud of my country or any other. Too many things that do not go well - anywhere. But today was one of these rare moments as I checked the law that prioritizes SARS2-Covid-19 vaccinations. They really tried to adjust the list to vulnerability and besides the oldest, there were e.g. people with trisomy or BMI above 40 in the top-level group.

 

[WWGD]

I'm rarely proud of my country or any other. Too many things that do not go well - anywhere. But today was one of these rare moments as I checked the law that prioritizes SARS2-Covid-19 vaccinations. They really tried to adjust the list to vulnerability and besides the oldest, there were e.g. people with trisomy or BMI above 40 in the top-level group.

Well, average person today lives much better by most standards than at any point in time: Life expectancy, Education, Fewer wars, less violence. Still a lot to do , but maybe a self-pat in the back would not be such a bad idea.

 

[WWGD]

Is there a reasonable way of changing the color of the cursor so that it contrasts with the screen colors; maybe dynamically? I mean, how much time have I spent looking for the cursor each session?

 

[Keith_McClary]

changing the color of the cursor

There are browser extensions and Windows (or other OS) apps that can change the color and shape.

 

[WWGD]

There are browser extensions and Windows (or other OS) apps that can change the color and shape.

Thank you. Dynamically, i.e., depending on the setup of the page being browsed? Edit: Meaning, e.g., a cursor will be colored black for a page with a white background and viceversa?

 

[hmmm27]

Reverse-colour arrow is one of the standard cursors : did they remove it for Win 10 ? ControlPanel>Mouse>Pointer.

There's also an option that if you type <Ctrl> on your keyboard a circle temporarily appears around the cursor. ControlPanel>Mouse>PointerOptions.

 

[WWGD]

Was it intentional that one of the membets of the Star Trek cast ( Tng, I think) looks like Mad's Alfred E Neumann?

 

[fresh_42]

I like the new world. My MS email account thinks I'm Swedish after years taking me for Spanish, my AOL account thinks I'm a republican living in Iowa, FB thinks I'm an American abroad, and probably has denounced me already at the IRS, and only Google leaves me alone. Isn't that funny? Google? They only try to figure out which music I like most, desperately and in vain. If you can't convince them, confuse them.

 

[WWGD]

I like the new world. My MS email account thinks I'm Swedish after years taking me for Spanish, my AOL account thinks I'm a republican living in Iowa, FB thinks I'm an American abroad, and probably has denounced me already at the IRS, and only Google leaves me alone. Isn't that funny? Google? They only try to figure out which music I like most, desperately and in vain. If you can't convince them, confuse them.

I keep getting ED promos, tooth decay repair and offers to help me finish my high school degree.

 

[WWGD]

My confusion is of a different nature: what's an app? You need an app ( a nap), you want an app with your meal ( an appetizer), or the standard , application. If my doctor asks me if I want an app, I will assume he means an appendectomy. I am saying no to that.

 

[fresh_42]

I keep getting ED promos, tooth decay repair and offers to help me finish my high school degree.

I haven't checked what they advertise. Especially the Swedish ads are a bit wild. AOL is easy to explain. It all started with the Obama campaign when I clicked through a few emails (from either side) just to see how they run their campaigns. Senator Ernst is doing her best to keep me republican ever since (Rep. Duckworth (D) has given up on me). I once signed in on a dating site (more than 20 years ago) and I still get "offers" from them and surprisingly some other clearly dubious sites.

 

[WWGD]

I haven't checked what they advertise. Especially the Swedish ads are a bit wild. AOL is easy to explain. It all started with the Obama campaign when I clicked through a few emails (from either side) just to see how they run their campaigns. Senator Ernst is doing her best to keep me republican ever since (Rep. Duckworth (D) has given up on me). I once signed in on a dating site (more than 20 years ago) and I still get "offers" from them and surprisingly some other clearly dubious sites.

I make it a point to have non-gmail accounts because it seems google is good at integrating all your online ( and, worse, otherwise) history.

 

[fresh_42]

I make it a point to have non-gmail accounts because it seems google is good at integrating all your online ( and, worse, otherwise) history.

I think it's a Don Quijote fight against windmills. Most immediate is FB in their responses to my surf habits. My gmail account is practically free from any spam. I regularly delete my google history, so it's merely youtube which tries to guess my taste. Well, they offer Springsteen and Chuck Berry, so nothing wrong with it.

 

[mathwonk]

As a student, (at Harvard no less), when asked to show the sum of two irrationals is not nec. irrational, I started from a non - repeating decimal, like .141592653589793..., then created another decimal, also non - repeating, say .858407346410206..., whose decimals added to 9 with each decimal I started with. It finally dawned on me, that starting from an irrational x, I had created the irrational number 1-x. Only afterwards did I think of just using -x. And I was in the "honors" class! So I empathize to some extent with your student on this problem.

 

[WWGD]

As a student, (at Harvard no less), when asked to show the sum of two irrationals is not nec. irrational, I started from a non - repeating decimal, like .141592653589793..., then created another decimal, also non - repeating, say .858407346410206..., whose decimals added to 9 with each decimal I started with. It finally dawned on me, that starting from an irrational x, I had created the irrational number 1-x. Only afterwards did I think of just using -x. And I was in the "honors" class! So I empathize to some extent with your student on this problem.

That's why/how laziness can be helpful. Just use x-x=0.

 

[WWGD]

I think it's a Don Quijote fight against windmills. Most immediate is FB in their responses to my surf habits. My gmail account is practically free from any spam. I regularly delete my google history, so it's merely youtube which tries to guess my taste. Well, they offer Springsteen and Chuck Berry, so nothing wrong with it.

You tube has offered me just about every type of music; a few times even things I liked.

 

[fresh_42]

As a student, (at Harvard no less), when asked to show the sum of two irrationals is not nec. irrational, I started from a non - repeating decimal, like .141592653589793..., then created another decimal, also non - repeating, say .858407346410206..., whose decimals added to 9 with each decimal I started with. It finally dawned on me, that starting from an irrational x, I had created the irrational number 1-x. Only afterwards did I think of just using -x. And I was in the "honors" class! So I empathize to some extent with your student on this problem.

I remember an exam when the student was asked about linear functions. She perfectly repeated the definition, but when asked to give an example, she struggled. I remember that I thought: "0." - "Do you know a nontrivial one?" - "1." However, I wasn't asked.

 

[WWGD]

I remember an exam when the student was asked about linear functions. She perfectly repeated the definition, but when asked to give an example, she struggled. I remember that I thought: "0." - "Do you know a nontrivial one?" - "1." However, I wasn't asked.

Good luck with that. I got so confused ; my students too, trying to explain the difference between a linear and an affine function.

 

[mathwonk]

When I took linear algebra it was all abstract, sort of like in Artin's Geometric algebra, and often in infinite dimensions. When I finally taught it, I was amazed that if you use matrices, in finite dimensions you can actually calculate most of that stuff!

 

[WWGD]

When I took linear algebra it was all abstract, sort of like in Artin's Geometric algebra, and often in infinite dimensions. When I finally taught it, I was amazed that if you use matrices, in finite dimensions you can actually calculate most of that stuff!

Infinite dimensions? Isn't that functional analysis?

 

[mathwonk]

I guess so, it was calculus according to Lynn Loomis, on Banach spaces. We learned that the derivative of f at p is a bounded linear map T such that the map f(x+p)-f(p) - T(x) is "little-oh" in the sense that its norm, divided by the norm of x, goes to zero with x. is that right? most of the class members were freshmen, but not me. the unoffical text was Dieudonne's Foundations of modern analysis.

 

[WWGD]

I guess so, it was calculus according to Lynn Loomis, on Banach spaces. We learned that the derivative of f at p is a bounded linear map T such that the map f(x+p)-f(p) - T(x) is "little-oh" in the sense that its norm, divided by the norm of x, goes to zero with x. is that right? most of the class members were freshmen, but not me. the unoffical text was Dieudonne's Foundations of modern analysis.

I remember seeing the example of a discontinuous( unbounded) linear map.

 

[mathwonk]

me too, maybe if e1,e2,... is an infinite sequence of unit length independent vectors, and T(ej) = j, then although ej/j-->0, T(ej/j) = 1, for all j.

(It seems I still know Banach spaces better than I know trig and one vbl calc.)
My conclusion was that since, given how I was taught, I did not understand anything, if one wants to understand, one should be taught the opposite to how I was. Of course that also may not be sufficient. Maybe it was actually my fault that I did not think and work hard enough, ask questions, look for examples? Nahhh...

 

[WWGD]

me too, maybe if e1,e2,... is an infinite sequence of unit length independent vectors, and T(ej) = j, then although ej/j-->0, T(ej/j) = 1, for all j.

(It seems I still know Banach spaces better than I know trig and one vbl calc.)
My conclusion was that since, given how I was taught, I did not understand anything, if one wants to understand, one should be taught the opposite to how I was. Of course that also may not be sufficient. Maybe it was actually my fault that I did not think and work hard enough, ask questions, look for examples? Nahhh...

I understood it a bit differently. The norm of the operator is the sup over the unit ball. We normalize a countable subset of the basis so that ||e_i||=1 . Then we declare T(e_i)=i (Standard norm on the Reals/Image), so that the Sup of the images goes to $\infty$. But I like your way too, to have more than one approach to see it be more understandable.

 

[WWGD]

I hear constant wailing by dogs every time they hear firemen alarms. Wonder if something could be done about it. I am not a crazy Peta person but they seem to go through a bad time.

 

[Jonathan Scott]

I hear constant wailing by dogs every time they hear firemen alarms. Wonder if something could be done about it. I am not a crazy Peta person but they seem to go through a bad time.

I think they probably enjoy the opportunity to sing along. I knew a dog who would start the moment he saw a violin case being opened, even before playing started. He definitely hated being shut out of the room.

 

[WWGD]

More on absurdly accurate (human) population counts:
The population of Mexico is 130,009,263...wait! , I was just notified 2 people just died and 4 were born. Make that 130,009,265. Why don't they just tell you130 million, or at least 130,009,000?

 

[fresh_42]

More on absurdly accurate (human) population counts:
The population of Mexico is 130,009,263...wait! , I was just notified 2 people just died and 4 were born. Make that 130,009,265. Why don't they just tell you130 million, or at least 130,009,000?

https://www.umrechnung.org/weltbevoelkerung-aktuelle-momentane/weltbevoelkerungs-zaehler.htm

 

[WWGD]

https://www.umrechnung.org/weltbevoelkerung-aktuelle-momentane/weltbevoelkerungs-zaehler.htm

I get that, but that is a counter intended to be accurate. I am talking about almanacs and websites like Worldometer Corona who use these ultra-accurate counts.

 

[WWGD]

Sorry if this is trivial: If I have an Excel spreadsheet: Is it possible to alphabetize ( " A to Z") several columns simultaneously? I remember once trying to do that and only one column was alphabetized, screwing up the whole spreadsheet. The process of alfa is clearly not reversible unless you notice right away and do a 'Ctrl+Z".

 

[Ibix]

Not without VBA, as far as I know. You can sort multiple columns in the sense that you could have a surname column and first name column and sort the table by surname then first name (i.e., Smith, Jane comes before Smith, John but after Jones, John), but not both columns independently (i.e. so that Jane comes before both Johns and Jones comes before both Smiths).

 

[Ibix]

If anyone knows a way, please do say. There have been a few times it would be useful and I've had to resort to jiggery-pokery due to not being able to do this kind of sort.

 

[WWGD]

Not without VBA, as far as I know. You can sort multiple columns in the sense that you could have a surname column and first name column and sort the table by surname then first name (i.e., Smith, Jane comes before Smith, John but after Jones, John), but not both columns independently (i.e. so that Jane comes before both Johns and Jones comes before both Smiths).

Thank you. I am not sure I understood your reply well. Say I have names in the order A,C,B and their corresponding last names in the order D , F,E. (Meaning full names are A+D, C+F, B+E) Can I sort , while keeping the match between names and last names, so that we end up with names column in the order A,B,C and last names in the order D,F,E ? ,i.e., the match between names and last names is preserved? Sorry if I misunderstood you.