QGIS 3 missing vector tab mac
Empty vector menu in QGIS on PC with French as default language
Induction and electromagnetic fields I've got a few questions on induction and electromagnetic fields. My current understanding of induction and electromagnetic fields is that, when electricity/current flows through a wire, it creates an electromagnetic field. If you twist that wire into a coil then you can concentrate that field. You can then induce current into a different coil by placing it inside of the electromagnetic field created by the first coil.  So here are my questions:  Q1. Does the electromagnetic field contain any energy?  EDITED QUESTION  Q2. Electromagnetic fields are the same as waves, so does that mean that when current is induced, they get the energy from electromagnetic waves being exchanged, or do they induce current directly from the electromagnetic field?   Q3. If electromagnetic fields and waves are the same, then doesn't that mean that you can induce current from waves? Therefore transferring electricity over long distances?  Q4. What spectrum of light are the electromagnetic waves that are in a field created by electricity?  Q5. Finally, why is it not possible to induce current from the Earth's magnetic field? I thought Maxwell said that electric fields and magnetic fields were the same thing.   Thank you to anyone who answers.  Edited Q2: So my original question (although asked poorly) still stands. Where does the current that gets induced in the secondary coil come from? How does the electricity transfer from the primary coil to the secondary? For example, is it taken from the stored energy in the e.m field? Does the field just act as a bridge between the 2 coils? Or do the 2 coils exchange e.m waves which carry the electricity that is being transferred from coil 1 to coil 2? Or is it none of these things and something completely different? Pointing the camera in a particular direction programmatically I'm trying to use Python to place a camera. I know the camera's location, and the forward and up vectors for the camera (i.e. the direction it's pointing and its orientation). How do I do this?  I know that it's possible to calculate a raw world matrix from the above information, which I can then apply to the camera, but I was rather hoping not to have to. Is there an easier way? Functions which are Continuous, but not Bicontinuous What are some examples of functions which are continuous, but whose inverse is not continuous?  nb: I changed the question after a few comments, so some of the below no longer make sense. Sorry. I want to resize the Unity launcher. Is that possible? I've been writing C and C++ code for almost twenty years, but there's one aspect of these languages that I've never really understood. I've obviously used regular casts i.e.  MyClass *m = (MyClass *)ptr;   all over the place, but there seem to be two other types of casts, and I don't know the difference. What's the difference between the following lines of code?  MyClass *m = (MyClass *)ptr; MyClass *m = static_cast&lt;MyClass *&gt;(ptr); MyClass *m = dynamic_cast&lt;MyClass *&gt;(ptr); I am new to Game Development, All I have developed is some 2d Games, using Game Maker by . There game development is much more easy, just as simple as Drag and Drop. But, Now I wish to evolve in Game Development, and wanna try some hands with the common programming languages like, Java, C++ or C. In order to achieve this, I came around the first topic, Game Engine. So, What is Game Engine.? That is a broad question, with various answers. I came out with some conclusion after reading various links,  Wikipedia: A game engine is a system designed for the creation and development of video games. The core functionality typically provided by a game engine includes a rendering engine for 2D or 3D graphics, a physics engine or collision detection (and collision response), sound, scripting, animation, artificial intelligence, networking, streaming, memory management, threading, localization support, and a scene graph.  It exists to abstract the (sometime platform-dependent) details of doing common game-related tasks, like rendering, physics, and input, so that developers (artists, designers, scripters and, yes, even other programmers) can focus on the details that make their games unique. Engines offer reusable components that can be manipulated to bring a game to life. Loading, displaying, and animating models, collision detection between objects, physics, input, graphical user interfaces, and even portions of a game's artificial intelligence can all be components that make up the engine.  Now what I understand is, Game Engine takes care of all the common work, like physics, loading etc... As far my question is concerned, what is a Game Engine (Programmatically)? Is it a Library? With pre-defined functions and classes, which can be inherited? Or what so ever, what is it? How to install Windows 7 from the network? Is it possible to install Windows 7 (Current RTM Version) on a computer without using removable media like DVD or USB?  The first thing that comes to my mind is through the network, but I don't have experience of doing a fresh install of Windows 7 via the network.  How to install Windows 7 via the network without any removable media?  P.S. I know some may think that doing so, is just a waste of time and it's easier to do it with removable media, but in the current situation the target PC neither has CD/DVD Drive nor supports booting from USB. And in addition to that, the target computer is connected to the network via a wireless connection (I don't know if it will cause any problems with the installation). I'm an elected diamond moderator on one site, and a user of several others. I think it would be extremely helpful for our flagging process if users had the option to enter freeform text explaining their flag on types of flags other than the "in need of moderator attention" flag.  An example of when this is relevant: Sometimes posts have had rude/abusive flags, but the rude/abusive part might be difficult to notice, or it might be a single word or sentence buried somewhere in the middle of the post. Users have to choose between "flag it as rude with no explanation" or "flag it as misc and explain what's going on". Often they'll pick the first because of course it seems like what they should do (e.g. they know the system has special handling attached to rude/abusive flags) but it means they can't explain what's going on to us, so we have to reach out directly in private to find out.  Sometimes it also helps to be able to explain why a comment is no longer needed, because past experience tells me the "no longer needed" flag on its own might be declined on a particular site -- so I pick the custom reason instead of "no longer needed" just so I can provide explanation.  I'd prefer users be able to understand they can pick the appropriate reason and be able to attach any explanation they deem necessary to further direct moderators to the issue. If not for all kinds of flags, then at least for spam or rude/abusive flags. Can a package overwrite the original commands in Latex? An example:  Without the amsmath package:   The equation environment numbers the equation automatically. The align environment cannot be executed.   With the amsmath package:   align and equation work seamlessly in numbering equations: I can use equation to write my first two equations, and align to write my third equation, and Latex will still number them correctly.   My questions are:   Is the code for the command equation after loading the amsmath package still the same as it was before loading the package? Moreover, if this is the case, then, in general, can loading different packages cause conflicts? And how do we avoid it? Why is any number (other than zero) to the power of zero equal to one? Please include in your answer an explanation of why $0^0$ should be undefined. How can we get the command line of a running application? iOS StackExchange app doesn't handle non-ASCII correctly The iOS StackExchange app doesn't handle non-ASCII characters correctly, see city name in the screenshot below. A  not only grants me a Sentinel Raven, but also the handy ability to see through its eyes.  Unlike the telepathic connection with a regular familiar, I don't have to use an action to do so.    If I am blinded, but my Sentinel Raven is not (and within telepathic range), can I use my raven's sight to cast spells that require me to see my target? Would this negate any disadvantage resulting from me being blinded? Or would I still suffer disadvantage, for example, because I have to cast from my raven's perspective and not my own point of view? How do you clear a stringstream variable? I've tried several things already,  std::stringstream m; m.empty(); m.clear();   both of which don't work. Should an adverb go before or after a verb? For example:     The word rarely turns up outside of those contexts.      The word turns up rarely outside of those contexts.   Which one is correct and why? For starters I am using this GREAT answer to achieve custom post types as well as a custom way to insert those post types into other pages, you can view that answer here:   I am running into a problem however when wordpress auto saves itself, it clears whatever metadata i have put into the forms.  EXAMPLE:  I select the 3 drop downs I want from my metabox and hit update.  The page reloads and the 3 choices are still selected.  In phpMyAdmin i can look up the metadata and see the array in place as it should be.  I now wait for wordpress to auto save.  As soon as this happens i can either refresh the page (not update, just refresh) and the metadata is lost, or i can look up the metadata in phpMyAdmin and it will display nothing (ie: its gone).  I'm guessing that this has something to do with needing to tie into another hook (some sorta auto update hook) or something, but even then it doesn't make sense that it would actually delete your metadata (rather than just not auto updating it).  Last note: If you copy and paste Mikes code into functions.php, you should be able to recreate my error (in wordpress 3.1) very easy. Cleaning Contaminated Disc Rotors I've had an eternal struggle with my current bike over brake contamination. The levers and calipers are shimano ultegra r8000, so the latest and (almost) greatest.  I first noticed it when I took it to a repair shop (i no longer use) for a bleed, it came back and the front brake would squeal like crazy and at low speeds had little to no braking force. You can stop from speed but then struggle to come to a halt without using your foot.  At around 2000 miles I tried to replace the brake pads, when I took them out they were black with grime on both sets (front &amp; back), not to mention worn down to the metal. I replaced them with the L04C sintered pads, gave the callipers a good cleaning with a towel (no chemicals) and fitted the new set.  Annoyingly all of my braking issues are back, now I probably should have cleaned the rotors, I simply used some muc off disc brake cleaner on them. I would like to know the best way to clean the rotors, I've inspected the pads and they are looking fairly black now, with plenty of tread left. I'm going to abandon these pads and fit a new set. For the rotors I plan to completely remove them from the wheels (they are center lock fitted) and try and treat them off the bike, what is the best way to fully clean them? They have plenty of wear left in them but you can see these black grooves in them, and plenty of muck on the back that I struggle to get off.  Below are images of the rotors after soaking them in disc brake cleaners, waiting and then wiping them down with a clean, microfiber towel.   Front Wheel Outside Rotor   Front Wheel Inside Rotor - note the increased dirt on this side  Looking at ways people clean their disc rotors, I've seen plenty of suggestions that I would need to burn the contaminants off the discs. Would the best approach be to remove them and use a blowtorch, should I soak them in some nasty chemicals overnight before I try to heat them? Do I try baking them in the oven?  And finally, what is the best way to prevent the brakes from becoming contaminated in the future? it's really off putting when they squeal and don't perform how I'd expect because it means I'm more reserved whilst out riding on the bike, leading to reduced time riding around outside. I commute on this bike (50 miles a week) and then ride about 50 on the weekends also, so it see's it's fair share of road use. I tend to wash it once after my big ride on saturdays and will rinse it off if it's been raining, any day that occurs (since I live in north east england, the acid rain..). I've owned disc brake bikes before and never had half the issues I've had with this, I had a cheap trek with tektro brakes and the brakes were sharper and never had any issues with contamination whatsoever (i did around 500 miles on that bike before a motorist happened).  Thanks for any and all advice :) Few days back while attending a thesis defense, one Professor was asking the defender why does he think, he deserves the degree. I was wondering since then, is there really any general answer for that? or the answer should be given describing my own work and then emphasis them how it is important for research field?  I asked the question here to know your opinion about it and to list down what could be the possible answers to this question. How do I convert the coordinates of a click to a tilemap position? How do you turn a tilemap (produced by TileD) for cocos2d where I can click on individual items and get a callback?  Is it just a case of converting captured touch and finding out where it is on the tilemap and then converting that to pixels  -- but that doesn't say what item was clicked on.  I have a tilemap of a city with buildings on it, and I'd like to be able to click or press on a specific building, get a callback.  What would be the best way to accomplish this? Easiest way to prove that $2^{\aleph_0} = c$ $\aleph_0$ is the cardinality of the set of natural numbers, $\aleph_0 = |N|$. $c$ is the cardinality of the continuum, i.e. the set of real numbers $c = |R|$.  I know that $|P(A)| = 2^{|A|}$. This means that the cardinality of the power set of a set is 2 raised to the power of the cardinality of that set.  This basically means that to prove  $2^{\aleph_0} = c$, I need to prove $c = |P(N)|$. I've seen the Cantor diagonal argument, although I have no idea on how to use it to prove this.   Could anyone suggest ideas of the simplest way to prove that $2^{\aleph_0} = c$?