irchans

From what I understand, low doses LSD or mushrooms sometimes (I think like 20% of the time) creates a long term (six months to permanent) change in mood for severely depressed people. I am also under the impression that there is no extra benefit from repeating doses more than once a year.

I think that walks in nature work significantly more often, but the effect is short term lasting days instead of months or years. Also, walking once or more a week is helpful long term.

I think I do my best thinking when jogging slowly.

I think that speech is also a pretty good superpower.

This is crazy. I never thought that anyone else would use those lectures to sleep. I like them when I'm awake also!

Wow. I kind of like that idea. I'm not sure it's true, but I like the idea.

We all thought that my dad was going to die from covid19. The doctors were very pessimistic. He lived. He recovered very slowly over the last 4 months. During the first month, he could not speak English (he was born in Norway), he needed 3 liters per minute of oxygen, and he could not stand up. Now, he has no trouble speaking, does not need oxygen, and he can walk 300 yards if he has a walker. Every month he has improved.

Hamilton the 2020 movie?

Would you mind expounding a bit on what "focused realization" and "imagination" mean in this context?

Maybe there are a few secrets to learning stuff. Has anybody taken the "Learning how to Learn" coursera course? https://www.coursera.org/learn/learning-how-to-learn?ranMID=...

It was my impression the Boeing had tried and failed to create a safe crew capsule. I am not sure if SpaceX succeeded.

I imagine that a large percentage (maybe 10%, maybe more) of the children in Sweden have been infected because they have more daily contacts and they "work" in crowded rooms. I am thinking that the kids could achieve herd immunity with very few deaths. Of course, any old person living with kids would have a large chance of dying (maybe more than 5% if over 70).

I'm 55 and I have mostly worked for three companies in my life: Penn State (10 years, started there 1990), Raytheon (3 years, started 1995), and a small hedge fund (started 1996, 12 years). I haven't worked for Penn State for about 4 years and I have lost touch with about 80% of the people I worked with there, but I still feel a strong bond to them. I have not worked at Raytheon for 15 years, and I've lost touch with 98% of my friends there, but every once in a while I do reconnect with them. I still work for the hedge fund and I do keep in touch with 50% of the people I met there even after they have moved on to other endeavors or retired. About half of my long term friendships came from work relationships.

Maybe "A first course in Abstract Algebra" by Fraleigh available on Kindle for less than $10. https://www.amazon.com/dp/0201763907

(It's not focused on Monoids. It also covers groups, rings, and fields from a mathematical point of view. It's written for an undergraduate math major with no prior experience in these areas.)

I used to love Forth. I haven't written Forth code since the 80's. Maybe it's time to try it again.

Haskell.

I lost my enjoyment for programming. I wrote very little code for about 5 years after burning out. One of my friends wanted to do a joint coding project and he suggested Haskell, so I solved one or two hundred project Euler problems in Haskell. I never got good at Haskell, but I really do enjoy writing smaller projects (less than 5,000 lines of code) in Haskell.

Haskell inspired me to read two fairly easy books on Category Theory. I really enjoyed that also.

I still don't write a lot of code. Every few months, there will be a problem at work that needs my help and then I write the equivalent of 3000 lines of C++. Or, there will be a math problem that I want to solve on the computer. I really enjoy writing those shorter, self-contained programs.

(PS: I started writing code in 1980.)

The number of new case per day in Italy has stabilized at 5000 to 6000 per day.

   Date      Cases  New Cases
   March 10  9172   1797
   March 11  10149  977
   March 12  12462  2313
   March 13  15113  2651
   March 14  17660  2547
   March 15  21157  3497
   March 16  24747  3590
   March 17  27980  3233
   March 18  31506  3526
   March 19  35713  4207
   March 20  41035  5322
   March 21  47021  5986
   March 22  53578  6557
   March 23  59138  5560
   March 24  63927  4789
   March 25  69176  5249
   March 26  74386  5210

Somewhat

I loved that essay :)

I seem to recall building small AM transmitters in elementary school. I don't remember if I used a transistor or not. I think it was easy to construct the capacitor and the inductor. (I build it in the early 70's and don't really remember how.)

We also made crystal diode radios, but I have no idea how to construct a diode from scratch, so maybe those are not simple.

Post-it Notes

I called my high school math teachers to thank them after I got a Ph.D. in Mathematics 13 years after I graduated high school.

You hit upon a very important point.

Suppose that you have a 2 planet system: A sun type star (mass 210^30 kg), an Earth type planet 1 AU from the sun (weight 610^24 kg), and a Jupiter type planet (mass 2*10^27 kg) that is 1000 AU away from the sun.

The distance between the Earth type planet the center of the star could be nearly constant.

The distance between the Earth type planet and the barycenter would not be nearly constant -- it would not "orbit" the barycenter in a circular orbit.

I may be wrong and I would be very happy if someone corrected me.

(Note: I think the barycenter would be about 5 AU from the star!)

I believe this is false in the sense that Mercury's orbit is more centered about the center of the Sun rather than the barycenter of the solar system (center of mass).

The article quotes Cathy Jordan,"Technically, what is going on is that the Earth, Sun and all the planets are orbiting around the center of mass of the solar system".

I believe that the statement is a good approximation for the orbits of trans-Neptunian objects or any other orbiting object that is more than 40 AU from the Sun, but I think it is a bad approximation for Mercury, and not a good approximation for the Earth. When I say it's a bad approximation, I mean that it would be more accurate to say "the Earth and Mercury orbit the center of the Sun" than it is to say "the Earth and Mercury orbit the barycenter of the Solar System (center of mass)".

Any comments by someone more qualified that me would be appreciated (I took about 6 courses in physics and 2 courses in astronomy in college and I graduated over 20 years ago).

I computed Fibonacci(20*10^6) using Binet's formula. The answer has 4179753 digits. I computed sqrt(5) to 4179753 digits and applied the formula. The result was correct.

The time to compute sqrt(5) was 0.23 sec. The time compute the formula (I dropped the insignificant 1-sqrt(5) term) was 2.8 seconds. When I used the built in Mathematica function to compute the Fibonacci number, it took 0.12 seconds.

I don't think it's too hard to get the sqrt(5) to a high enough degree of precision. (Probably could use Newton-Raphson.) On my computer it takes about 0.05 seconds to compute sqrt(5) to one million digits. It takes about 0.01 seconds to multiply two 500,000 digit integers. If you want to computer F_n using Binet's formula I think you need about (log(F_n)/log(10) + 10) digits for sqrt(5).

Nice. Thanks for that.

I am wondering if all three methods (sqrt(5) method, 2x2 matrix exponentiation, and jacobolus's power of two method) take approximately the same amount of time --- slightly less than O( log(F_n)*log(F_n)^2) (using Fürer's algorithm for integer multiplication.)

Interestingly, I learned to program in a completely different way. When I started in 1979, the computer terminal where I learned could only run BASIC. There were no directories, just BASIC. We had one book that could teach you most of the commands, IF--THEN GOTO, SET, PRINT, FOR, NEXT, GOSUB. There was no WHILE statement. I think I spent months playing with those before learning about arrays. The biggest breakthrough was finding a Star Trek game in BASIC. I was amazed at what could be done with such simple commands. After a year or two, my father bought a TI 99 4A computer and I got a Commodore 64 about a year after that. You could write assembly code on the C64. I learned about ASCII file input and output in 1982. I don't remember learning about directories until I got to college in 1983. I don't think I used any libraries before 1986. (I did use punch cards in 1982). I think the first time I saw UNIX was 1990. I don't think I saw a package manager before the 1990's after I had been programming for over 10 years. The first time I did object oriented programming was about 1994 I think, C++. I got an MSCS in 1996.

I like Techdragon's idea "I’d write it in math" and Onion2k's "I'd build a mechanical system."

A lot of it depends on the complexity of the software and the complexity of the interface to the user(s). If the software merely needs to do something simple like accounting, I think a mechanical system could be made, especially one that processes punch cards (see Vaylian's answer). Mechanical systems usually require some maintenance, but if you made many copies of the mechanical system and many copies of the documentation, then you could probably still run it in 100 years on one of the mechanical computers.

If the software is an unchanging, complex, but it has a simple interface (like terminal standard input/output ascii), then consider: 1) writing the software in an old language like C or Lisp, 2) compiling the software into a Turing machine, and 3) writing a program in Fortran, C, or Lisp that can run the Turing machine quickly. (In particular the implementation should make memory access a constant time operation.)

If the interface is complex, like the internet, or graphical, then you are pretty much hosed. Somebody is going to have to maintain the interface, but you could still use the Turing Machine idea to implement the logic that is not tied to the interface. As Patio11 said, your #1 problem is "making an organization which persists for 100 years." I suggest finding an organization that has lasted 100 years and making one person responsible for the software with the idea that he/she will maintain the software/hardware for at least 40 years and then pass along the responsibility to someone else. You would need some good contracts to make this happen, but it is not too unusual for a teacher to teach in the same high school for 40 years, so you could probably design the contracts accordingly.

You should probably write the documentation in English and put it on acid free paper.

The bottom lines are: 1) Compile into a very very simple language, 2) Implement on very simple hardware (Onion2k), and 3) Set up a human organization (Patio11) as simple as possible with good contracts that will last 100 years.