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  1. 5 points
    At which point, I have to post this: https://what-if.xkcd.com/1/ Spoiler: it doesn't end well
  2. 2 points
    Sound we regularly experience carries very little energy. 80 dB is ~ 1 milliwatt, so assuming 100% efficiency: “to heat up a quarter liter of coffee 50 C it would take: 1 year, 7 months, 26 days, 20 hours, 26 minutes and 40 seconds” https://www.physicscentral.com/explore/poster-coffee.cfm 130 dB is just 10 watts, though it is logarithmic https://en.wikipedia.org/wiki/Sound_power
  3. 2 points
    My very short answer: A value of a random variable. Let's say you receive a symbol "1". If this is the only possible symbol the fact that you received it does not give you information. But if this symbol is one of two possible, "0" and "1", then the reception of symbol "1" may contain information. So having more that one symbol is a requirement, but not sufficient. Lets say you receive the pattern "111111...". The probability of the symbol "1" is 1. Again there is no information. But if random sequences are allowed, for example "00", "01", "10", "11" then we may use these sequences to represent information. So conceptually information can be seen as a value form of a random variable. The above is an attempt at an extremely short introduction to information theory, which is tied to discrete probability theory. Most important early contributor was Claude E. Shannon and his paper “A Mathematical Theory of Communication”, dealing quantitatively with the concept of “information”. Shannons concepts and the mathematics he used to describe information and to measure information content is a remarkable contribution. I believe it's tricky to find any areas of IT where his work does not contribute. Wikipedia* has links to some concepts related to your question. Feel free to ask additional questions. *) https://en.wikipedia.org/wiki/A_Mathematical_Theory_of_Communication For an early predecessor of Shannon, working on sinus signals and frequencies, see Hartley: https://en.wikipedia.org/wiki/Ralph_Hartley
  4. 2 points
    No. They are purely about the "completeness" of formal systems. In other words, can a formal system (e.g. mathematics) prove that anything that can be written down using that formal system is either true of false. And the answer to that is no. You can write something using mathematics that you cannot use the same mathematics to prove or disprove. You can extend your formal system to make it more complete and allow you to prove that statement. But then there will be other statements that this extended system cannot prove. And so ad infinitum. Physics uses mathematics but it is not limited by that mathematics in the same way. (And some mathematicians complain that physicists are a bit "ad hoc" and don't really stick to absolutely formal derivations.)
  5. 2 points
    That is out of my knowledge. The only thing I can say is that trying to change the elements (river, sea, land) in a specific way most of the times drive to unexpected results. I have the experience where a hotel constructed a small dock in the sea for his single inflated boat sportcraft had the result to erase completely its sandy beach.
  6. 2 points
    Since this is the lounge I'll do some less rigorous analysis showing why science is of no use. Observations in the movie clip. 1: Zoro does not seem to follow the trajectory of a massive object; heigh above ground seems maintained. 2: Zoro does not seem affected by air resistance; speed is not reduced during the flight 3: There is atmosphere on the world where the fight takes place. 1: means that (a) Zoro is either massless* and hence unaffected by gravity or (b) neutrally buoyant in the atmosphere, like as a hot air balloon. 2&3: means Zoro could be (c) extremely dense, having extreme momentum. But (c) can't be compatible with 1, massive object fall down. And (b) is not compatible with 2, balloons stop quickly when thrown in air. (a) is pointless, a massless Zoro, swords included, would have zero effect on a stone golem; there is no kinetic energy or momentum that can affect the golem. That means Zoro travels through air by magic because the described airstrip is physically impossible. I do not know how magic affects drag and Bernouilli's principle, so again: Side note: That fact the manga story is failing to describe physically probable action does not mean I can't see it as entertaining. I enjoy entertaining stories, if the canon of the universe where the events take place allow magic, faster than light travel etc I don't care how impossible that might be according to mainstream science. I just chose to not mix my interest in science and engineering into the events of fiction and fantasy in the story. *) I know that would mean a photon speed of c in vacuum and massless bodies of macroscopic size does not exist AFAIK; creating one would require magic. But this is the lounge after all, and we will get to the point anyway.
  7. 2 points
    If you have scientific evidence for a non-mainstream topic, and you think you can defend it reasonably, put it in Speculations. If it pertains to a field of personality studies you can defend using science, post in Psychiatry/Psychology. If it's something you feel might pertain to a specific philosophy or ethical approach, post in Philosophy. If it's just New Age mysticism that works because you say so and wave your hands a LOT, please don't post anything at all.
  8. 2 points
    There are things the Bible doesn't say and almost everybody believes it does. There was no apple. It could have been a quince, or maybe a fig, as there were no apples back then in the Middle East. The Bible doesn't say it was an apple, actually. The Bible doesn't say Jonah was eaten by a whale either. The Bible doesn't say there was an angel at the Garden of Eden, but a cherub, which was a mythical animal represented very frequently in the gardens of palaces throughout the Middle East. The Hebrew Bible doesn't say that Mary was a virgin, but a "young woman." ------------------------------------------------ There are things the Bible says and few people know it does. The Bible talks about a pantheon of gods that are subservient to Yahweh. And names God both as Yahweh and El. Is it the same god? I'm not sure. Asherah, the wife of Yahweh, is also mentioned, but the interpretation was presumably changed, as it's mentioned as a synonym for "a stick" in very obscure passages, when she is known to have been a goddess, as archaeology has shown. The stick was one of the symbols of the goddess. Back to Adam and Eve: There's at least one thing the Bible says twice in different (incompatible) ways: Ezechiel 28. Two prophecies, one of them against the king of Tyre. There you can see that the king of Tyre is expelled from the Garden of Eden, on account of his sins. The cherub also appears. Very similar legend; two different narrative uses. Who was expelled from the Garden of Eden, Adam and Eve or the king of Tyre? I'm not so sure. The authors of the Bible seem not to be either. Some scholars believe the Oracles against the king in Ezechiel 28 predate the Adam and Eve story in Genesis. ------------------------------------------------ There are things the Bible says that are taken from somewhere else: The Bible takes the story of Noah from The Epic of Gilgamesh, Utnapishtim , and adapts it to its own narrative needs. ------------------------------------------------ There are blatantly obvious things the Bible is silent about: Omri, big king of Samaria, was a very relevant character of the Assyrian domination period, but the Bible only mentions him in passing, as a baddie. The Bible also plays down the role of many other kings, like Manasseh, although he made Israel into an important olive oil factory and brought a period of peace, contrary to what Hezekiah, his father, did. ------------------------------------------------ And lastly, there are many things the Bible says that cannot be true. Josuah didn't conquer Jericho, as Kathleen Kenyon has proved. Jericho was uninhabited at the time. Plus the Egyptians were in control of Canaan and had the country strongly policed from Beit She'an. I don't believe God gave the law of gravity a suspension for some hours for the benefit of his people to the detriment of the Canaanites either. Plus the Canaanites and the Israelites were the same people: No difference in material culture or belief system, as Israel Finkelstein has shown. Abraham could not have possibly used camels. Camels were domesticated about 1000 years later.
  9. 1 point
    I want this thread to be an attempt to create a generalized overall mapping of mathematics as we know it at this current time. Its basis is that all models developed by a human is itself a model, therefore I do not want to delve to deeply into the philosophy of the subject matter, whereas I would like for this to be an overall model of existing mathematics from beginner to expert levels all explained and viewed as a general "mapping." Showing the interconnections between all of the different mathematical concepts formed which have been agreed upon. Showing all the twists and turns, all the connections, all of the branches that lead to no where. This is a big project, I am not blind to that. However I believe that providing an overall visual mapping of mathematics as a whole will allow for a sort of "key" for future persons, a minute or a millennia away, to quickly and easily view the processes that exist so that they themselves can go back and see the holes in their knowledge. While also quite possibly coming up with new ideas and adding to the overall mapping of the analogous "cinematics math's universe." The goal of this project is for anyone, anywhere, at anytime to be able to learn all of mathematics in a minute. To be able to master it and contribute to it in a matter of moments. I would also like for this to grow into something more, one in which instead of conceptualizing the concept of mathematics and guessing what exists based on a developed mental mapping, there is one that actually exists. Where you can add your own name to. Like a gigantic tree of knowledge or something. Thank you for your time
  10. 1 point
    If we could remove the extremes at either end, our current system could lead to less of a focus on acquiring more wealth than is necessary. If we want to curb extreme greed and poverty, regulation is our best friend. I know this because of how much the obscenely wealthy hate it, and how much the devastatingly poor need it.
  11. 1 point
    Okay that was my bad I will try to avoid it. Thank you.
  12. 1 point
    Text books are about the next best thing to formal training. I never pay attention to anything YouTube unless I can quarantee the poster is a well accredited physicist in the field of his or her expertise. ( The field of physics is highly diverse. I can quarantee someone like Swansont far beats my skills in his specialty. While I have my own specialty (cosmology)). So research on a topic should never be blind faith. If you cannot find numerous support on a theory by different professional opinions then be wary. Lol though I give credits to Studiot for applied engineering physics, Marcus for relativity and Janus for astrophysics. The information in this thread does not meet any criteria to question the second law in thermodynamics in any cosmology related studies I am familiar with including QFT related applications. You are absolutely correct to question the above. So +1 for that.
  13. 1 point
    You guys go ahead and burn all your money. I'll see how it works out, and MAYBE I'll do the same. But I won't be the sucker who goes first.
  14. 1 point
    As with everything else you see on YouTube, be prepared to do some research on your own ( in good old fashioned books ), to separate the wheat from the chaff, AND the 'made-up'.
  15. 1 point
    Here are some lecture notes starting with -Review of discrete probability theory (5 pages) This may guide you towards what parts of math you wish/need to check. -Shannon's measure of information (15 pages) kind of "Mathematical relations between probabilities and information content" http://www.isiweb.ee.ethz.ch/archive/massey_scr/adit1.pdf I've not checked the details of the pdf but it looks decent; found it by searching for university course material for information theory. Note: following is based on a mix of formal studies and practical experience from engineering. It may or may not match what an active scientist would say. Maybe a table of concepts, bottom up*, and corresponding examples of related computer science task or concepts will help: Overview: 1: Information Theory: Entropy of information. Mathematical foundation. Practical examples: Theoretical capacity of a network connection. lossy vs lossless data compression, parity checking, error correction 2: Information Representation: What is used to represent data, what does the bits mean at a basic level Practical examples: Low level protocols. Character sets such as unicode. Concepts; line endings, byte orders 3: Information structure: Data structures usually tied to programming and algorithms Practical examples: What are hash tables, linked lists, trees, graphs 4: Higher level information organisation: organisation such as databases. Practical example: SQL database, Data lake Study: When I first studied computer science the order was 3, 2, 4 + 1 (4 and 1 was parallel IIRC). Right before 3 was some programming and algorithms was immediately after 3. I guess you could be a good programmer with knowledge of only (3) but knowledge of the other helps. *) 1-4 are my rough way of ordering the things for this discussion. There are overlaps, there are examples where the order is different and there are many cases where 1-4 would be nested.
  16. 1 point
    When I was younger (the 1960s) I used to look forward to the Analog Science Fiction Annual every year. One year there was a short story called "Business as Usual During Alterations" Essentially some Aliens dropped a matter duplicator onto theEarth. At first everyone thought that would be the end of 'commerce and work and MONEY' But then some enterprising souls got a duplicator and started offering the service to "Duplicate your stuff for you to your requirements" And the good old American Dream was saved.
  17. 1 point
    Not sure I grasp the idea completely but maybe the "the map of mathematics" could act as a starting point or act as a rough guide? It is a one page drawing showing how many concepts such as pure mathematics, applied mathematics, number systems, topology and many other fits together: https://www.flickr.com/photos/95869671@N08/32264483720
  18. 1 point
    It's normal in the intestinal tract. Maybe somebody else will chime in.
  19. 1 point
    "I am a layman trying to understand above theorems. This could be a stupid question." There is no such thing as a stupid question! "Does these theorems imply that we actually cannot prove that 2+2 = 4???" Gosh, I may have to reconsider! No, Godel's theorem say that, given any set of axioms large enough to encompass the properties of the non-negative integers there must exist some theorem that can neither be prove nor disproved. It does not say that a specific theorem cannot be proved. In fact, if we were able to identify a specific theorem that can not be proved nor disproved, we can always extend the axioms, perhaps by adding that theorem itself as an axiom, so that theorem can be proved. Of course, there would then be still another theorem that cannot be proved nor disproved.
  20. 1 point
    It is generally a immunological effect that is not due the disease per se (there are exceptions and certain diseases can effectively wipe out your adaptive memory, but this is not one of those). Roughly speaking it is the reaction of your body to the antigen that determines how long your body remembers it. However, there are a lot of unknowns regarding what precisely makes a response long-lasting. It is not my area of specialization so I cannot really say how far the research in the area has progressed, but from discussions it appears to me that the field is still wide open in that regard.
  21. 1 point
    Just about every major pursuit is going to provide employment, but few investments give the kind of global returns that space exploration and other scientific endeavors do. The amount of new knowledge produced is fairly staggering, every time we take the risks to expand our knowledge and banish our ignorance.
  22. 1 point
    This proposal is a result of my noticing how often certain issues crop up and was prompted by the following posts, which come from different threads. Before offering a draft version I would like to ensure two things. Assurance from the moderators that this is in order and will not lead to being called out as a blog. The opportunity for interested other members to participate in the drafting; I do not pretend to have all the answers. Maybe you should make article and make it sticky what dimension means in physics.. so they won't confuse it with sci-fi vision of other dimensions.. So I am suggesting two main areas for inclusion 1) Dimensions and degrees af freedom. 2) The Relations of Constitution and the Conditions of Compatibility and their implications for any proposed Theory of Everything (TOE). Please have you say here so that the final post can be transposed to the locked sticky.
  23. 1 point
  24. 1 point
    Pretty much everything in mathematics can be proved. There are a few well-known problems that have not been proved yet (some have substantial prizes associated with them). It took over 300 years before someone proved Fermat's Last Theorem. That is partly because it had to build on a huge amount of mathematics that was developed in the meantime. Some very simple looking problems can be very hard to solve. Some quite complex sounding problems, that people have struggled with for decades, might turn out to have a really simple proof. (Mathematics is one of the few files where outsiders can, and do, make breakthroughs.) There are lots of unknowns in mathematics (e.g the continuum hypothesis; that there is no infinity between the (infinite) set of integers and the (infinitely larger) set of reals) that have not yet been proved either way. And there are some problems for which it can be proved that there's no solution. But I don't think you can ever say that a particular problem is unprovable because of Gödel Incompleteness. Unless it is a problem specifically constructed to be unprovable for that reason (which is how Gödel proved the theorem; by constructing a mathematical statement that could not be proved in the rules of the system).
  25. 1 point
    Symmetric is the term your looking or in this case also commutative. (Under constant velocity) This is shown as the inner product of the Minkowskii group is symmetric via [math]\mu \cdot \nu=\nu \cdot \mu[/math] The equations are linearized however that doesn't necessarily describe reversible functions.
  26. 1 point
    I stated before that the assumption was that the suspect is already intent on violence. If the suspect isn't intent on violence, then of course, no physical force from the officer should be used. What I stated was, WHEN the suspect is already physically attacking the officers they need to be prepared to deal with it and control the situation. Your position is unrealistic. If someone is intent on violently attacking another person, asking them nicely to stop simply isn't going to work. I agree with most of this. Over-policing needs to stop. Mass incarceration needs to stop. Racial profiling and systematic targeting of the poor needs to stop. Policing for profit needs to stop. Police brutality and use of excessive force definitely needs to stop. Significantly more resources need to be allocated to social work, mental health facilities, and PERMANENT economic stimulus for chronically depressed areas to alleviate the vicious cycle of crime and poverty. 100% yes to all of that. However, at the present time there is still a need for police. So the question is, what kind of police do we want? Effective police require an investment. Right now society isn't investing in police in the way it should. Even the admirable Scandinavian nations with abundant social programs still have police - and as we've discussed, they pay for it. Like it or not, American society in its present form is still extremely violent. There are numerous mafias and street gangs that would love to have complete autonomy if police are defunded and restricted in their ability to exercise authority, not to mention every two bit criminal with a grudge against society. I'm simply saying that violent confrontation is a part of policing, and how officers respond to violent confrontation matters a great deal. If they're untrained, they'll reach for their gun at the slightest provocation. If they're trained well, they will have a range of other options at their disposal to successfully diffuse the encounter. Just trying to be realistic given the context of the situation, that's all. ------ Here is an excerpt from Norway's 2020 budget whitepaper: Security Security is a prerequisite for freedom. Crime breeds insecurity. The population therefore needs to be protected by the rule of law, a strong and effective police force and a credible defence capability. This is reflected in the budget for 2020 with a NOK 2.5 billion increase in defence sector appropriations for, inter alia, investments in new submarines, maritime patrol aircraft and artillery for the Norwegian Armed Forces. We are preparing for an increase in military activity and strengthened emergency response preparedness. This meets the targets the Government has set in the 2017-2020 long-term plan for the defence sector, and will expand the defence budget by more than NOK 8 billion in real terms over the period covered in the long-term plan. The Government is planning for a continued increase in police presence. The budget proposal allows for the recruitment of graduates from the Norwegian Police University College in 2020. In addition, appropriations are increased to cover the full-year effect of the recruitment of graduates in 2019. More funds for the police will strengthen the capacity of police districts to prevent, investigate and prosecute crime. It is proposed to provide the police and the Norwegian Directorate of Immigration with funds in order to enable the implementation of new Schengen systems for border control and monitoring. These systems will improve capacity for detecting and preventing crime, ID fraud and illegal migration. To facilitate follow-up of the Security Act, the Government is proposing to increase appropriations for the Norwegian National Security Authority (NSM). The proposal facilitates digitalisation and improved efficiency and quality in the security clearance of personnel. Moreover, the Government proposes initiatives to improve the ability to prevent, detect and manage security incidents in emergency preparedness communications. Source: https://www.regjeringen.no/contentassets/09814fbc520946869d6eaa65099c2983/national_budget_2020.pdf Page 13. -------- Note: 2.5 billion Norwegian Kroner is approximately 262,000,000 USD ---- And from Sweden's 2020 budget whitepaper: The fight against crime and its causes will be intensified. Society must be strong enough to protect people from everything from petty crime to terrorism. The Swedish Police Service will be given additional resources. Work on employing 10 000 more people in the Police by 2024 will continue to strengthen the Police’s capacity to better fight serious organised crime, for instance. As the number of court cases is increasing and a larger number of criminals are being sentenced, the Swedish courts and the Swedish Prison and Probation Service will be allocated additional resources. The capacity to combat welfare crime and money laundering will be improved. The Swedish Prosecution Authority, the Swedish courts and Swedish Customs will be strengthened. Honour-related violence and oppression will be made visible, pre-empted, prevented and punished. The whole of society must play its part in combating and preventing crime. Source: https://www.government.se/4ad5f1/contentassets/e8bf49ea1bbe41fda780895657ae94e0/from-the-budget-bill-for-2020-budget-statement.pdf.pdf Page 5. ----- From the Finnish 2020 budget: PUBLIC ORDER AND SAFETY EUR 816 million is proposed to the police force. The appropriation is used to launch measures that aim at increasing the police officer person-years to the level determined in the Government Programme, 7,500 person-years, by the year 2023. To ensure the performance of the operators involved in preventing and solving criminal offenses and the implementation of prosecution services, additional funding amounting to EUR 5.2 million is allocated to the prosecution service, courts, legal aid, and the Criminal Sanctions Agency. A one-off addition of EUR 2 million is proposed to focusing evidence on the District Courts. Source: https://julkaisut.valtioneuvosto.fi/bitstream/handle/10024/161822/Budget review 2020 October 2019.pdf?sequence=4&isAllowed=y Page 15. ------ The point is, even as safe and prosperous as these Scandinavian nations are, non of them are thinking about defunding their police forces. US police by comparison are already woefully underfunded by State and local governments and we want to take more money away from them? It's not logical.
  27. 1 point
    The old man cracks a stone, not a stone golem. The golem has the power to move and talk, magical properties that I do not know how they affect the stone's physical properties. If the golem can bend its limbs, how soft is it? Does it crack or does it cut like flesh? How does these magical properties stand against a magical sword? Again: After that repetition, let's try another angle at science: Ok. You just need to provide the mathematical formulas that models the physics in this fantasy world. We need a comparison to the real world laws of physics and the numerical values for parameters, constants or conversion factors etc. With a model we can calculate, simulate and/or predict the outcome of certain events in the fantasy world. In case the parameters are not officially available I guess you can request them from the author. We also need some way to make observations in the fantasy world so that our predictions can be tested. Note that the above is both a reasonable and realistic request. And maybe also not too far from "real science"; scientists run simulations of real physical events, where sometimes some parameters are unknown or aspects of the real world are not known. Comparisons with observations are made and parameters may be adjusted. Simulations in cosmology is one area of science I think of. Simplified mathematical models are also quite common when dealing with stone golems and swords. Games such as dungeons & dragons* contains the mathematics of such interactions. Intention is of course to have a balanced game play and a reasonable chance to analyse and predict a situation; do I attack or run? What are the odds that I can take on the golem with my sword? Should I hide and wait for backup? Is the golem immune to magic, should our wizard friend stand back? etc. Again, the creator of the world and/or specific adventure need to provide the numerical parameters required before we can roll the dice and observe the outcome. The "science" aspect of this is that I guess some basic skills of statistics and probabilities are needed to create the world in such a way that it is playable and not an unpredictable random mess. For a more physics related example we could use computer games as an analogy. If we would create a Zoro 3rd person action game, what parameters would we feed the physical engine to allow for a fun game where the stone golem boss is not too hard and not too easy to beat? "Observations" in this case could be the beta testers; does the physics of the world in the game match real physics enough? Expectations of fans of the series? Is the game "fun"? Does authors and other stakeholders approve? And some science: Do we try to be too realistic so the game requires too expensive hardware, limiting the market? What does the latest papers in computer science say; are there any new and novel algorithms that we can use, allowing this game to stand out against the competition? As you see there are a few thinks to consider when trying to apply science to the events in the manga. I really understand that such discussions could be quite interesting, for instance among fans that wish to create a fan-made game true to the canon of the series. But it may take some research to get the details needed, can you provide them? *) I'm not that much into such games these days, I think you can have a look at D&D 5th Edition Compendium
  28. 1 point
    I think I can do a little bit more than that. Most, if not all, interesting wave functions in QM have a behaviour that goes to zero as a Gaussian at infinity. If you take a look at most eigenfunctions of "realistic"* Hamiltonians, for example, the harmonic oscillator, hydrogen atom, etc. The all are dominated by exponential damping at infinity. Example: \[\psi\left(x,0\right)=\frac{e^{-x^{2}/2-if\left(x\right)}}{x^{n}}\] Now it's very easy to see that no matter what power of x is integrated against the exponential, the idea works. \[\int_{\mathbb{R}}dx\frac{e^{-x^{2}/2+if\left(x\right)}}{x^{n}}\frac{d}{dx}\left[\frac{e^{-x^{2}/2-if\left(x\right)}}{x^{n}}\right]=\left.\frac{e^{-x^{2}}}{x^{2n}}\right|_{-\infty}^{+\infty}-\int_{\mathbb{R}}dx\frac{d}{dx}\left[\frac{e^{-x^{2}/2+if\left(x\right)}}{x^{n}}\right]\frac{e^{-x^{2}/2-if\left(x\right)}}{x^{n}}\] Watch out for silly mistakes. * Meaning nothing pathological, like Airy functions, or something like that.
  29. 1 point
    No, no. Careful. That's not the point. The point is that the integrals, \[\int dx-\left(\frac{\partial\psi^{*}}{\partial x}\psi\right)\] and, \[\int dx\psi^{*}\frac{\partial\psi}{\partial x}\] differ in what is called "a surface term" or "a boundary term". Because in quantum mechanics the boundary is at infinity, they can be identified for all intents and purposes. If you equate one of these integrals to its complex conjugate, what you're saying is that the integral is real. That's not quite so correct. The integrals are equal except terms that vanish at infinity. The point is a bit subtle, but that's the way to read its meaning. Edit: In this case, the surface term is, \[\left.\left(\psi^{*}\psi\right)\right|_{\textrm{infinity}}\]
  30. 1 point
    So basically you’re suggesting we can only fix this problem by hiring members of the Gracie family to police our streets? Seems unrealistic, but okay. I think more is needed, like federally set bare minimum standards about what is and is not allowed and what happens when those thresholds are crossed. The defund the police objective is a poorly framed way of asking for funds to be out to better uses. It’s not at odds, it’s exactly what they’re seeking. Yes, who wouldn’t? But why present a false choice / false dichotomy? It’s not like those are the only 2 options available. They could also buy me a cheeseburger or get me engaged with a social worker.
  31. 1 point
    The training point is about more than just "recertification" each year being only 5 hours. The US also badly fails up front in preparing cops for their jobs in the first place. https://work.chron.com/long-train-cop-21366.html https://www.theatlantic.com/international/archive/2020/06/america-police-violence-germany-georgia-britain/612820/ The rest of that 2nd article from The Atlantic also has good ideas on how to begin repairing our broken system.
  32. 1 point
  33. 1 point
    Here is the spreadsheet. I have calculated enough iterative values for different values of lambda {2, (1+√5) ,4} and starting values {0.35, 0.40, 0.45.} It can be seen that lambda =2 quickly converges, lambda = 4 displays the famous 'frequency doubling between two values' and lambda = 4 results in a chaotically varying result. I have appended the spreadsheet for anyone who wants to play with it. chaos1.xls
  34. 1 point
    Incandescent sources, like the filament in a light bulb, are very 'dirty'. The light they emit spans a range of wavelengths/frequencies, in a 'lopsided' Gaussian distribution, peaking at the wavelength/frequency characteristic of the temperature of the filament ( see black body radiation curves ). What you want is an emission which is characteristic of a specific energy difference, which will give only that specific energy ( frequency/wavelength ). LEDs are one such source, as they emit light at the characteristic energy of their band gap, and are readily sourced in differing colors. Lasers would be another source, as they emit light based on electron orbital transitions ( again a specific energy difference), but are a little harder to source.
  35. 1 point
    I'd be embarrassed to admit how many hours i've wasted in the tub thinking about that one... (in my defence...never an hour at one time)
  36. 1 point
    Well let's put it this way. There are testable models for dark energy and matter already developed that involve QFT and the Higgs field. For example DM could be right hand neutrinos which the SM model predicts but has never observed. DR could be a result of the Higgs field itself. Example GUT theories http://arxiv.org/pdf/0904.1556.pdf The Algebra of Grand Unified Theories John Baez and John Huerta http://pdg.lbl.gov/2011/reviews/rpp2011-rev-guts.pdf http://pdg.lbl.gov/2011/reviews/rpp2011-rev-guts.pdf GRAND UNIFIED THEORIES DARK MATTER AS STERILE NEUTRINOS http://arxiv.org/abs/1402.4119 http://arxiv.org/abs/1402.2301 http://arxiv.org/abs/1306.4954 Higg's inflation possible dark energy http://arxiv.org/abs/1402.3738 http://arxiv.org/abs/0710.3755 http://arxiv.org/abs/1006.2801 A theory of Quantum gravity would be solved if we discovered the Graviton. This would solve the singularity problem and revitalization. What is missing isn't viable models. What is missing is the confirmation evidence. In order for any viable model to be confirmed you must have some means to test the viability of said model. These articles will give you some direction. This article will familiarise you with cosmology //www.wiese.itp.unibe.ch/lectures/universe.pdf:" Particle Physics of the Early universe" by Uwe-Jens Wiese Thermodynamics, Big bang Nucleosynthesis
  37. 1 point
    yes. but..it has been a bit late here and i had intented not to write until OP gives more contexts. ... have a good night.
  38. 1 point
    I think you got it wrong: Gannets and barracuda fish better together Edit: x-posted with Mordred +1. Couldn't have given you better advise.
  39. 1 point
    So you are arguing that NO ONE can criticize your paper because YOU did not include a "working roadmap" or "outline"?
  40. 1 point
    Surviving the acceleration is one of the problems, regardless of method. Limiting yourself to ~1g or so puts a limit on how quickly you can make a trip.
  41. 1 point
    ! Moderator Note You seem to have come to a science forum by mistake
  42. 1 point
    @ahmet I interpret the dot "." as end of a sentence. Reformatting the above using separate lines for each sentence: 0+0=0 0+1=1 1+1=2 That seems to be ok examples to illustrate the question asked? I do not see 0=2. Maybe I miss something.
  43. 1 point
    I would just like to add in some words of caution here. Dimensions are often identified with degrees of freedom. Both have a (numerical) value. These concepts are not the same, although sometimes their values coincide. They are all too often confused with each other. Further it is important to identify the 'space' in which you are working - phase space, configuration space, geometric space and so on. The dimensions of these different spaces can (and often do) differ for the same 'system'.
  44. 1 point
    Well let's start with the term dimension in physics. This includes string theory. Dimension is any independent variable or mathematical object that can change in value without changing any other value. The common example bring (t,x,y,z) each of these coordinates (spacetime) can change in value without affecting the other value. Now in particle physics including QFT and QM. The effective degrees of freedom from the various particles will often be described under a dimension basis. For example the SU(2) group is two dimensional. While the SU(3) group is three dimensional. In string theory they describe a point particle as a string. This describes its Langragian ie how the particle will behave. It isn't some fundamental component on its own but rather a method to describe its wavefunctions. There is no separate parallel universes involved in the use of the term dimension. The 11 dimensions of string theory is referring to independent mathematical objects. Phase space or configuration or parameter space is simply a means of representing different types of graphs. Ie one can graph the relations between different parameters and how the evolve. The space does not necessarily entail a physical volume.
  45. 1 point
    Well, only in countries like the UK and USA. I doubt you would find one in the rest of the world. Don't know about Canada or Australia, though. I have one that also has points and picas.
  46. 1 point
    I think it makes no sense to say that the vedas were twisted or not. They have grown organically. There are so many reasons for a text to change, especially when it originally was an oral tradition. Without having the 'original' how would you see that the texts changed? There are methods to find out which of the present versions we have are probably the oldest, but of course we can have no idea what the first written down version of the vedas were. And then there are many reasons why texts change over time, just to name a few: errors when copying the texts corrections of (language) errors authors putting in their ideas into the texts, in good or ill faith I only know a little about the history of Christian texts, which are of course not so old as the vedas, and also here already the problem exists that we do not know exactly what the original texts were. But we know copyists made errors, corrected errors, put in sentences or even complete stories, often because these copyists had a theological agenda to promote their version of Christianity. From some texts we know that there must have been more original texts, but they did not survive. With the vedas this will be worse, because they were orally passed to others for a much longer time. In Christianity, especially the new testament, there are at most only about 100 years between the oral tradition and the first written down versions we have (often less: the gospels were written till about 100 years, the earliest one probably only 30 years, after Jesus' death). With the vedas it is several millennia before they were written down.
  47. 1 point
    Real world complication example: how willing the buyer is willing to pay a given price will strongly correlate how well the care is running.
  48. 1 point
    It would be a startling coincidence if the Earth was 'captured' at just the right angle to align with the ecliptic plane. All solar system planets orbit in the same plane; the largest deviation is Mercury, at just 7 deg inclination. Most likely because they coalesced from the rotating plane of dust/gas during the solar system formation. Pluto, which is no longer considered a planet, was most likely captured, as it is a full 17 deg out of the ecliptic.
  49. 1 point
    The shortest distance between a point and a line (which is what is meant by "the" distance between them) is along a line perpendicular to the line. The line is given by y= 6x+ 3 so has slope 6. A line perpendicular to that has slope -1/6. The line through (6, 2) with slope -1/6 is y= (-1/6)(x- 6)+ 2 so 6y= -x+ 6+ 12 or x+ 6y= 18 Substitute (two lines which intersect) y=6x+3 into x+6y=18 and you get: x + 6(6x+3) = 18. x + 36x +18 = 18 37x +18 =18 37x = 0 x = 0 So that means that x=0 at the point where the lines y=6x+3 into x+6y=18 intersect. Substitute y = 6x + 3 y = 6(0) + 3 = 3 y = 3 The point of intersection is (0, 3). Then, use the distance formula to find the exact distance between (0,3) and 6,2) d^2 = (x2 - x1)^2 + (y2 - y1)^2 So the distance between (0, 3) and (6, 2), squared, D^2= (0- 6)^2+ (3- 2)^2= 37 and then D= square root (37).
  50. 1 point
    This is a poorly worded argument. Come on, you can do better than this. Of course it EXISTS, it's here, it's a real thing, despite what you might think about its efficacy. Your argument is trivially proven false. Whether it should be taken seriously as a study is what you're really talking about. The fact is, MANY people have been helped by psychiatry. I can EASILY provide many citations supporting this argument. That some didn't get help doesn't mean it should be "dismantled". Would you dismantle Alcoholics Anonymous just because it doesn't work for some people?
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