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Everything posted by Acme

  1. It is a feedback loop, but not necessarily strange. Hofstadter describes the camera/screen setup in detail and differentiates what is seen and how it is generated and discusses the implications. In fact, Chapter 5 is titled On Video Feedback and it explores the phenomenon in depth. On the cover of his book is one such image and starting after page 204 there are a couple unnumbered pages of 16 color images illustrating different video feedback effects. Hofstadter jealously guards his copyright which is why the Wiki articles on his work are short and few quotes from his writings are found elsewhere. There is no substitute for reading I Am A Strange Loop and Gödel, Escher, Bach as they are logical arguments in toto, just as are mathematical proofs. Neither book is for the faint of heart.
  2. strange loop Note: Escher's Drawing Hands appears in Hofstadter's book just below the quote as above on page 102. Immediately following Escher's drawing in the book, Hofstadter expounds on the 'transfinite' nature of the drawing and its relationship to strange loopage. Check it...check it good.
  3. Wikipedia has a decent page with many references to books and other pages. History of astronomy @ Wikipedia Web searching "history of astronomy" returns many more sources. On the particulars of determining the mass of solar system bodies and orbital parameters, Newton's calculus was -and is- the fundamental tool.
  4. Sounds like you are taking adequate precautions and kudos for your concern. Here's a recent article on the issue, though the concern appears to be exposure to children actually at the range. You could allay your fears by having your son tested for lead by his doctor. Lead Poisoning: A Hidden Danger at Shooting Ranges
  5. Battery terminal spreader & cleaner pliers https://www.amazon.com/KD-204-Battery-Terminal-Spreader/dp/B000JFL7X0/ref=sr_1_1/159-1049674-0275921?ie=UTF8&qid=1483993854&sr=8-1&keywords=battery+terminal+pliers
  6. It's not gas escaping from the ground that causes the needles, and the bubbles are due to air coming out of solution with the water as it freezes. The needles are a type of frost heaving. Frost heaving Needle ice PS I notice this phenomena -and have photographed it as well- in my garden soil fairly often. I'm just across the Columbia from you. Here's a shot from last year.
  7. How harsh should I be then? But seriously folks, what manner of education do you suppose has blunted the critical thinking? Could it be...oh I don't know...religious education? To be clear, I'm all for the original poster coming here to try and do better than going to a religious forum. Edit: Also, it's a good point you make by specifying 'evangelicals', who seem to be the best credentialed science bashers. The Catholics -more specifically the Pope-, while they have their own issues in the critical thinking realm, don't have a problem with the science behind AGW. Pope calls global warming sin, says protecting creation is work of mercy
  8. Mmmm...wouldn't n2 - n + 41 where n is 0,1,2,3, 4 ... produce the same number of primes? Then there is the Ulam spiral & primes. Note: This source cites Euler's polynomial as the form I suggested as equivalent to studiot's. Are they equivalent in terms of the number of primes they produce?
  9. Primes are a subset of the set of natural numbers. (As studiot pointed out, 'field' has a specific meaning in mathematics beyond your apparent colloquial use.) There is no end to investigations into primes & their relations to natural numbers such as prime gaps, ending digits of primes [in whatever base], twin primes, etc. Pick your poison and drink deeply.
  10. Implicit in this statement and the thread title is the idea that theology lacks the critical thinking that is the hallmark of science. It's not an uncommon meme here. The faithful seem content to accept science until they perceive it to contradict this or that article of their faith and the facts be damned.
  11. A Genius Explains Edit: I think I meant this response for your other thread, Arithmetic - the node way Either way, Tammet's talent is apparently structurally based, albeit in damage to the 'normal' brain structure. Without understanding the damage, notwithstanding understanding 'normal' structure, it seems unlikely one could emulate it either in a brain or a machine. One never knows I suppose, as accident is as accident does.
  12. Galvanic corrosion In your case the electrolyte is likely dirty water.
  13. Indeed, Indian mathematicians did & do know and use the idea, though I can't attest to the exact era of its inception. See the Wiki on Vedic Squares. Moreover, the idea extends to any base so that, for example, in base twelve the digital root of a number that is divisible by eleven is always eleven. Thirty-three12 = 29 & 2+9=B, where B is the digit eleven.
  14. What I gather from the abstract is that the researchers did experiments -real-life- and the math. I have had the page bookmarked for a number of years because I once saw a nickel land on edge at a bar and I was curious about the odds. (There was quite a squabble about how to settle the 'bet'.) As far as I was able to determine, the actual paper is behind a pay wall.
  15. Probability of a tossed coin landing on edge by Murray, Daniel B.; Teare, Scott W., Physical Review E (Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics), Volume 48, Issue 4, October 1993, pp.2547-2552
  16. Ideally, a central heating system is balanced in regards to the number & volume of rooms and the size and number of ducts and capacity of the blower. Completely blocking one room duct can cause backpressure on the blower which can make it work harder and use more juice. I'm not sure how this affects the efficiency of the heat source, whether it be gas or electric. ?
  17. Carrots on sticks Charon. The problem, as I understand it, with the snow blower is that the driveway is a narrow passage between two buildings so there's no room to throw the snow.
  18. So the winch I had in mind happens to be one that I own. Runs off a 12 volt auto or -preferably- deep cell marine type battery and has a remote operating switch. >> Portable winch So, let's follow the KISS principle. Tie down the winch at the end of the driveway. Use signposts, fence posts, stakes, or vehicle hitch. Add a small board to the back of the snow shovel and at the bottom scraping edge of the blade. Attach a yoke to the outside ends of the board and attach the winch line to the yoke. Pay out enough line to take a reasonable size bite -maybe 6 ft. ?- and with the remote switch & shovel in hand, stick the shovel in, turn on the winch, and guide the shovel by its handle and scrape out a gob o' snow. Rinse and repeat, side to side across the drive and resetting the winch as necessary to reach further back in the drive. I don't see that the ad specifies line length; mine is 30 ft. Also, there is no reverse on the switch, rather you have to loosen a clutch nut on the side of the unit and drag the line out by hand. Neither the ad nor my manual give an amperage rating so I won't even hazard a guess how long it would run on a 100AH battery before you need to recharge. 'Course you could hook right up to your running vehicle's battery, presuming it's not stuck in the garage or otherwise inconveniently located. Whatever you try, please favor us with photos! Good luck!
  19. Aye, this is the bridle attachment problem to which I referred. The true method of knowledge is experiment. ~ William Blake
  20. Beauty, like supreme dominion, is but supported by opinion. ~ Benjamin Franklin
  21. Well, I ain't young, but I am a genius. In a word, snow winch. Wait...that's two words. Anyway, use a dragline powered by a winch, come-along, or other suitable device and attach the line to your snow shovel, a board, or other suitable blade. You will of course have to play with the bridle to get and maintain the correct angle of attack and of course use suitable material for the bridle. Braided steel cable sounds right, as it will have to cut through the snow when you initially jam the blade in. There snow reason this won't work. Here's a rough diagram:
  22. cross-post It used to be normal accepted behavior to burn witches and own slaves -to mention a couple other proxy situations- so what is your point? Mitch McConnell and his ilk never got over Obama; isn't what's good for the goose, good for the gander?
  23. Find out just what any people will quietly submit to and you have found out the exact measure of injustice and wrong which will be imposed upon them, and these will continue till they are resisted with either words or blows, or with both. The limits of tyrants are prescribed by the endurance of those whom they oppress. ~ Frederick Douglass
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