Why are Hermione's efforts to free the House-elves so incompetent?
Could Hermione really free the Hogwarts house-elves with her knitted hats?
How many rationals of the form $\large \frac{2^n+1}{n^2}$ are integers? Reading data from a relational database into a LaTeX table I'm using Tex Live 2009 on Debian squeeze. I can upgrade if I really, really  have to, but I'd rather not. I was wondering if it would be possible to do the following.  Given some data in a (relational) database, can I extract it and automatically format it in a LaTeX table, so one would not need to manually recreate the LaTeX table if the data changes? Could one do such a thing with Lua? One would normally use a suitable language database adaptor for this, and I see Lua has . I'd like to use PostgreSQL. I'm currently using version 8.4.  Solutions not involving Lua are also fine. Just to be clear, I don't know anything about Lua and my knowledge of LaTeX programming is also extremely skimpy. I'm looking for a recipe which I can adapt if necessary. While this is not really important for my current use case, it seems like a useful general technique if possible. What is function of force $F$ and work $W$? Lightning Web Components: navigate to the 'new' object page passing in specific record type Id? I am using LWCs to display lightning cards in a list.  The list shows information about Programs.  Each Program card has a button, and this button needs to take the user to the 'new object' screen of the Application object.  Here is my code:   applyToProgram(event) {     // The recordTypeId is coming from the .html     // I have verified that the value is correct.     var rtId = event.target.id;      // How do I use rtId below?     this[NavigationMixin.Navigate]({         type: 'standard__objectPage',         attributes: {             objectApiName: 'Application__c',             actionName: 'new',             nooverride: '1',             recordTypeId: rtId  // This does not work         }     }); }   This is not working.  The user is presented with the 'new object' screen for the object's default record type and NOT the one specified in rtId.  I tried putting 'nooverride' and 'recordTypeId' in the state:{} argument, and I also renamed 'recordTypeId' to just 'recordType'.  None of these worked.  Can anyone help me with the correct syntax?  Is this even possible in LWCs?  Thanks, Jeff I recently submitted an application to the AppExchange, only to have it not pass the security check due to "Insecure Storage of Sensitive Data Vulnerability." The problem is that my app accesses an external API, for which it has its own API Secret and API Key. These are static, and specific to the Salesforce App- they will be the same for all users, all installations, etc.  Perhaps stupidly, I stored them as private properties of the class that uses them.  private static String apiSecret = 'superS3|&lt;R37'; private static String apiKey = 'sameHerebutdifferent';   It is a Managed app, so users cannot see them. As such, I am puzzled as to 1. why this is insecure and 2. how better to store these values, given that we are apparently operating under the assumption that having them in the text of the class itself is insecure. Circular duplicates strike again It looks like this issue has , but it just happened again on Travel.SE. Perhaps this is another corner case? These two questions are closed as duplicates of each other.           I had the last vote on each, although in both cases, my vote was for "Unclear what you're asking", but the weight of votes in both cases were for the duplicate status. So if the existing checks are only in place at the time someone casts a close vote, that would explain how this one got in under the radar. Perhaps another check needs to be done when the question is actually closed, not just when close votes are cast?  And as @gnat points out, low-rep/logged-out users get a Redirect loop when trying to load either question.  NOTE: A moderator has already fixed this particular circular duplicate situation by closing one of the questions with a different close reason. Layers with same coordinate system should align/overlap in ArcMap but do not? I put 4 different layers into my ArcMap document, but only one of them will show up on the map! I should be seeing the other 3 layers as well. When I do a Zoom to layer, I can see one layer, but I cannot figure out how to make the other 3 show up at once on top of each other.  Before I opened ArcMap, I used ArcCatalog where I right-clicked 3/4 of the shapefiles and  clicked Properties &rarr; Coordinate system &rarr; Import and then clicked on my Trees layer, which has the coordinate system I want the other 3 to have. But when I opened ArcMap the 4 layers did not overlap, nor could I move them above or below each other. Does "Delete Local Content" retain save files? If you remove a single player game installation with the Delete Local Content option from the Steam Libary, in general will save files be deleted or retained? I am putting together a GIS server using GeoServer and need some help with importing my layer styles from ArcGIS 10 to  format.    I have one layer in ArcMap properly symbolized and labeled, how can I get this layers symbolization and labeling into a SLD file? Where is the Layers panel in Blender 2.8? I am starting working on Blender 2.8, but I can't find the layer panel. Where is it? Should I put a comma before the last item in a list? Should I put a comma before the last item in a list?     I would like crackers, cheese and some soda.   I would like crackers, cheese, and some soda. The tag  and meta-tag  syntax generate much nicer looking results than merely surrounding your tag with [square brackets].    However, they only work when you're talking about the site you're on.  On Area51, in Chat, and on Meta sites, this is frequently not the case, leading to attempts at syntax like [[tag:failure]](https://superuser.com/questions/tagged/failure), which produces:    Hmm, must be some subtle syntax thing:   : [tag:failure](https://superuser.com/questions/tagged/failure) []: [[tag:failure](https://superuser.com/questions/tagged/failure)] : [tag:[failure]((https://superuser.com/questions/tagged/failure))] : &lt;a href="https://superuser.com/questions/tagged/failure"&gt;[tag:failure]&lt;/a&gt; : [tag:failure][1] \n\n [1]: https://superuser.com/questions/tagged/failure : [more text is a [tag:failure] too](https://superuser.com/questions/tagged/failure)   I give up!  How can I create a link to a tag on another site with tag markdown? Connecting MySql with Android without using PHP 2D graphics - why use spritesheets? I have seen many examples of how to render sprites from a spritesheet but I havent grasped why it is the most common way of dealing with sprites in 2d games.  I have started out with 2d sprite rendering in the few demo applications I've made by dealing with each animation frame for any given sprite type as its own texture - and this collection of textures is stored in a dictionary. This seems to work for me, and suits my workflow pretty well, as I tend to make my animations as gif/mng files and then extract the frames to individual pngs.  Is there a noticeable performance advantage to rendering from a single sheet rather than from individual textures? With modern hardware that is capable of drawing millions of polygons to the screen a hundred times a second, does it even matter for my 2d games which just deal with a few dozen 50x100px rectangles?  The implementation details of loading a texture into graphics memory and displaying it in XNA seems pretty abstracted. All I know is that textures are bound to the graphics device when they are loaded, then during the game loop, the textures get rendered in batches. So it's not clear to me whether my choice affects performance.  I suspect that there are some very good reasons most 2d game developers seem to be using them, I just don't understand why. A better answer was posted long after accepting another. Should I accept the new one? Every infinite subset of a countable set is countable. Here is the proof I tried to weave while trying to prove this theorem:     Theorem. Every infinite subset of a countable set is countable.      Proof. Let $A$ be a countable set and $E\subset A$ be infinite. Then $A\thicksim\mathbb{N}$. This implies that there is a sequence $\left\{x_{n}\right\}_{n\in\mathbb{N}}$ where $x_{n}\in A$. Construct a sequence $\left\{n_{k}\right\}_{k\in\mathbb{N}}$ where $x_{n_{k}}\in A$, $n_{1}$ is the smallest positive integer such that $x_{n_{1}}\in A$, and $n_{k+1}&gt;n_{k}$. Then      $$ E=\bigcup_{k=1}^{\infty}x_{n_{k}}, $$      and $E$ is countable, because $E\thicksim\mathbb{N}$. $\blacksquare$   Is it convincing? Difference between $(this) and event.target? I am very new to the TikZ package, and I need to draw some flow chars by using the following shapes.   However I couldn't figure out how to draw the 4th and and 6th ones below. It would be very nice (for completeness) to help with all of the shapes in the list below.      Your help will be greatly appreciated.  Note: I have visited  but it contains some other shapes. If I'm floating in space and I turn on a flashlight, will I accelerate? Photons have no mass but they can push things, as evidenced by .   Can photons push the source which is emitting them? If yes, will a more intense flashlight accelerate me more? Does the wavelength of the light matter? Is this practical for space propulsion? Doesn't it defy the law of momentum conservation?  Note: As John Rennie mentioned, all in all the wavelength doesn't matter, but for a more accurate answer regarding that, see the comments in  .  Related Wikipedia articles: , The limit of a sum $\sum_{k=1}^n \frac{n}{n^2+k^2}$ as $n\rightarrow\infty$