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Sensei

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Everything posted by Sensei

  1. I think so computer science, is science on it's own. It has not encountered in mathematics things, like loops, infinite loops, recursion, infinite recursion, overflow, stacks, arrays, dynamic arrays, sorting of arrays, IEEE floating points (and optimizations basing on it), compilation, linking, pre-processing, virtualization, OOP classes, virtual and non-virtual methods and functions, returning objects (with "infinite" dimensions), taking "infinite" amount of parameters, and so on, so on. Some of these things were researched by mathematicians, just because it was needed for computers. Old computers, just computed, get input data, processed them, returned final result. One and not variable. Modern computers don't work the same way (or rarely work this way). They receive inputs all the time from human, sensors, detectors, cameras, from internet, and so on, so on. Before they manage to process old data, there is even more new data to process. It can/is infinite. Bots scanning Internet can go on, and on, and on. Never finding the end of their program.
  2. Let me explain how vacuum tubes can work. In vacuum tube there is positive electrode, which accelerates free electrons, and negative electrode, which has abundance of electrons. There can be used light, IR, visible, or UV, or x-ray, or gamma photons, to eject these electrons. f.e using photoelectric effect on negative electrode. https://en.wikipedia.org/wiki/Photoelectric_effect or thermionic emission https://en.wikipedia.org/wiki/Thermionic_emission to accelerate rate of creating new free electrons on hot cathode https://en.wikipedia.org/wiki/Hot_cathode Once they are ejected, they cannot go back to negative electrode (because it's repelling them), so they are accelerated toward positive electrode. If there is nothing else done, electrons are hitting positive electrode, decelerate, emitting photons to conserve energy, and go by wire. However, if there is hole in positive electrode, and there are used magnets/electromagnets, which bend their trajectories, electrons fly through hole. And such device we call electron gun. https://en.wikipedia.org/wiki/Electron_gun Then they fly through vacuum, and hitting 2nd side of vacuum tube ("screen"). If it's made of fluorescent material, after hitting it by free accelerated electrons, photons in visible range are created (otherwise there are made UV/x-rays). To capture UV/x-rays there is used thick lead glass https://en.wikipedia.org/wiki/Lead_glass https://en.wikipedia.org/wiki/Radiation_protection (to protect human behind screen) If nothing is done to electrons, you will get single spot on screen. To bend trajectory there can be used external electric field (abundance of electrons on one side, and absence of them on second side), or external magnetic field (electromagnet, true magnet, superconducting electromagnet). So, if you want to current go from AB or AC, where A is cathode and B and C are anodes, you can control trajectory of electrons toward B, or toward C, by controlling current flowing by wire of electromagnets in vacuum tube (2nd side), or creating high voltage on electrodes in vacuum tube (2nd side).
  3. Imagine you are in the middle of I century AD, in Roman Empire, are you supporting Caligula.. ? Or are you against him.. ? Are you supporting Nero.. ? Or are you against him.. ? For me you are supporter of either Caligula and Nero.. Supporter of whatever government you live in..
  4. Correctly would be to say that some black holes have higher mass than stars (when they lived long enough and consumed neighborhood stars and matter). Typical fresh newly made black hole has smaller mass than primary star, because star ejected significant amount of matter in supernova explosion, prior collapse the rest to BH.
  5. DVI has three versions, DVI-A analog only, and DVI-D digital only, DVI-I integrated (both). Obviously digital has the best quality.
  6. Almost every .NET Framework application I am starting from writing this code (right after making controls and resizing routines). Made even my own faster Store/RestoreForm() methods (stored in registry). StringJunky, when you will be disconnecting 2nd monitor, you absolutely must make sure, in the all applications in which you moved their windows to 2nd monitor, are moved back. Otherwise searching for where they stored this info (registry/configs) will give you huge huge headaches. Or you will have to reconnect monitor just to move them back..
  7. C'mon swansont. He was curious about scientific issue. "Particle having some spin" means "how they behave while flying close to external magnetic field", like in mass spectrometer. Pions, kaons, have all spin 0, and are all detectable. Charged particles leave trace in Cloud Chamber, Bubble Chamber, for instance. https://en.wikipedia.org/wiki/Cloud_chamber https://en.wikipedia.org/wiki/Bubble_chamber If particle is unstable, trace is ending, and two, three or rarely more, traces appear from that location where it decayed.
  8. Pair production. https://en.wikipedia.org/wiki/Pair_production
  9. Wait couple months, when grapes will be cheaper (September-October), and make your own wine. To make "pink wine" squeeze grapes, and ferment just juice (from 1 kg of grapes you can get approximately 700-800 mL of juice). To make "dry red wine" squeeze grapes, and ferment them couple days, without removing remains of grapes from juice. Filter after 2-3 days or more. Now it's good time for fermenting Cucumbers, and Cabbages. To make ethanol you would need lab equipment for distillation (graham condenser and perhaps dephlegmator).
  10. Why would you like to spy people.. ? Don't you have your own life.. ?
  11. Majority of human painters are watching thing they want to paint, person, animal, scenery or nature, and then try to reproduce it as close as possible.
  12. It's electron anti-neutrino. I will add to this that on Earth free neutrons can be created by cosmic rays (mostly Solar wind), in the same reaction in which Carbon C-14 is made: [math]p^+ + p^+ \rightarrow p^+ + n^0 + \pi^+ [/math] (cosmic ray accelerated to relativistic velocity) [math] ^{14}_7N + n^0+ \rightarrow ^{14}_6C + p^+[/math] (neutron capture and ejection of proton to conserve energy/momentum)
  13. I will provide link to wikipedia, so OP will be able to read about it. https://en.wikipedia.org/wiki/Loop_quantum_cosmology
  14. Just a few words prior [math]\tau\tau[/math] there was anti-bottom quark with proper overline.. Looks to me as sloppy omission.
  15. Carbon C-14 radiometric dating method is NOT used for the real fossils. C-14 has half-life only 5730 years. It is used to date ancient organic based remains made by human, remains of human f.e. mummies etc. It works reliable only to ~ 50,000 years. To check date of rocks and minerals there is used radioactive isotope of Rubidium-87 for example. https://en.wikipedia.org/wiki/Rubidium-strontium_dating In this thread I showed some calculations: http://www.scienceforums.net/topic/104881-isochron-plots/?p=983374
  16. Now you're doing duplicate of entire list every iteration (that's always very slow), and recursion... Binary-search algorithm does not need them. Implement binary-search as separate function (split code to logic blocks), which is simply returning -1 and index at which what we're searching for is present. And then in upper level, the main code, check if( result != -1 ) which means something is found, and do code related to it.
  17. Sort array of urls and use proper binary-search instead of brute-force algorithm. It will require just 11-12 string comparisons, instead of 2400..
  18. You're just member of group, or you truly believe in that Earth is flat.. ? These are two different things. One can be member (like this forum) without actually believing in it..
  19. Excuse me, tau- anti-tau, should be written as: [math]\tau \bar{\tau}[/math] (they lacked overline above anti-tau)
  20. You can make C/C++ Firefox and Chrome plug-ins, which will be working parallel to browsers, and checking whether user is visiting website from the list (downloaded from website one time per week/month), and informing him/her about probably not so high quality knowledge presented on it. People using these websites, from 3rd party world especially, probably have no idea what does mean "predatory publisher", and are using them as knowledge database.. With plugins it will be automatic. But they will have to be advertised as filters for students and teachers.
  21. Write in foreign language, and you won't even notice how crappy your spelling is..
  22. Yes, of course, if they are unstable they will decay after a while. In particle accelerators like LHC/CERN inside chamber there are external electric and magnetic fields, which bend paths of newly created particles, so positive charged particles are flying in opposite direction from negative charged particles, and they're starting making "circles". In Bubble chamber (now ancient) particle detector, there is liquid Hydrogen, and x-rays are used to make photos many thousands times per second. Paths of accelerated particles are visible on photo, and can be analyzed.
  23. When you have high kinetic energy particle (accelerated to significant part of speed of light), upon collision there can be created pair of particle and its antiparticle, to conserve quantum numbers. In this article you have examples of calculations of energy needed to create such pair: http://galileo.phys.virginia.edu/classes/252/particle_creation.html On the bottom there is pair of proton-antiproton antimatter. After creation from really fast moving particles, newly created pair is also accelerated to significant velocity, thus they don't annihilate immediately, and can be captured by electromagnetic traps. f.e. https://en.wikipedia.org/wiki/Ion_trap
  24. Kaon indeed has two charge neutral variations, K0L long and K0S short, which have different half lives. https://en.wikipedia.org/wiki/Kaon
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