I'm wondering why Hagrid isn't allowed to carry a wand or do magic.  We know that Hagrid carries a pink umbrella with the suspected remnants of his broken wand secreted inside (CoS chapter 7), and that Hagrid does do magic here and there even though he's not supposed to (SS chapters 4 and 5).   We learn in Chamber of Secrets that Hagrid was expelled from Hogwarts (CoS chapters 7 and 13), and that his wand was snapped in half. However, canon also states that witches and wizards are not required to attend Hogwarts; they can attend a different school, such as Beauxbatons or Durmstrang, or be homeschooled (DH chapter 11). To me, this suggests that a witch or wizard doesn't necessarily need to attend a school in order to become fully-qualified. While it doesn't expressly say so in canon, I note that the Weasley twins still use magic routinely after they quit Hogwarts (OOTP chapter 29). Why would expulsion from Hogwarts preclude Hagrid from learning and using magic?  Why can't Hagrid have a functional wand and be allowed to perform magic?
Why was Hagrid's wand snapped in two when he was expelled from Hogwarts? Why was he banned from performing magic? Yes, he was expelled from Hogwarts after being framed by Tom Riddle as being responsible for Moaning Myrtle's death via Aragog the Acromantula. But why did he receive this punishment?  ‘What’ve you been feeding [the pumpkins]?’ said Harry. Hagrid looked over his shoulder to check that they were alone. ‘Well, I’ve bin givin’ them – you know – a bit o’ help.’ Harry noticed Hagrid’s flowery pink umbrella leaning against the back wall of the cabin. Harry had had reason to believe before now that this umbrella was not all it looked; in fact, he had the strong impression that Hagrid’s old school wand was concealed inside it. Hagrid wasn’t supposed to use magic. He had been expelled from Hogwarts in his third year[...] Chamber of Secrets - page 90 - Bloomsbury - chapter 7, Mudbloods and Murmurs  Why would Hagrid's wand be snapped in two and he not be allowed to do magic when:  Attendance and completion of an education at Hogwarts was not compulsory by wizarding law¹; homeschooled children were allowed to do magic for their lessons, and then do magic fully when they turned 17. The Weasley twins dropped out of Hogwarts after practically destroying parts of the castle with fireworks (and conjuring an awesome swamp on the fifth floor), yet were allowed to do magic despite not completing Hogwarts or any kind of homeschooling curriculum (that we know of). No Death Eater character that we know of was banned from using magic, despite their crimes and devotion to Voldemort. I don't recall any Death Eater wands being snapped and the owner banned from performing magic after being convicted of Death Eater crimes (please do correct me if I'm wrong). For example, Bellatrix Lestrange's wand was not snapped in Goblet of Fire when she received a life sentence in Azkaban and, as we know, her wand played a fairly significant part in Deathly Hallows.  ¹I realize in Deathly Hallows Voldemort made attendance at Hogwarts compulsory; however, by that time, Hagrid had been cleared of the charges of being responsible for Myrtle's death and was allowed to use magic again.
Drawing arrows on an HTML page to visualize semantic links between textual spans I have an HTML page with some textual spans marked up something like this:  ... &lt;span id="T2" class="Protein"&gt;p50&lt;/span&gt; ... &lt;span id="T3" class="Protein"&gt;p65&lt;/span&gt; ... &lt;span id="T34" ids="T2 T3" class="Positive_regulation"&gt;recruitment&lt;/span&gt; ...   I.e. each span has an ID and refers to zero or more spans via their IDs.  I would like to visualize these references as arrows.  Two questions:   How can I map an ID of a span to the screen coordinates of the rendering of the span? How do I draw arrows going from one rendering to another?   The solution should work in Firefox, working in other browsers is a plus but not really necessary. The solution could use jQuery, or some other lightweight JavaScript library. Hosting multiple distinct folders for distinct domains I have a VPS that I've installed a Apache Web Server on. What I want to do is forward my own website domains to that server and host those websites' files inside my Apache Web Server. As far as I understand a DNS server is required to manage which domain is hosted where (IP-wise). But what I want to do is host my websites under the same IP address, the one that my web server has. How can I separate those websites' files inside my web server so I don't have to use http://host/foo for www.foo.com and http://host/bar for www.bar.com? How can i set different wallpapers for Ubuntu 15.04 login and Desktop This has been bothering me very much. i have memory that Ubuntu 12.04 had this configuration? am i wrong? finally, is it possible for the login screen to have different wallpaper from the desktop? is this possible in Ubuntu 15.04? i would appreciate a stable understandable response. thanks :)  -ben I'd like to use a sequence of boxes to show how TeX works. I read some time ago that everything (or almost) in TeX are boxes.  So, how to show only the TeX boxes that surround each character, each line, each paragraph?  I'd like something similar to the image below, not fbox which contains blank space around it. How can I copy a file from another directory to the current one? I have this problem as part of a school assignment:  NOTE: In case it's hard to read in the image above, here's the directory tree: $ tree . `-- sample_dir1     `-- sample_dir         |-- admin         |-- cambridge         |   |-- cafeteria         |   |-- library         |   `-- security         |       |-- annex         |       |-- building         |       `-- parking         |-- faculty         |-- history.exe         |-- markham         |   |-- annex         |   |-- building1         |   `-- parking         |-- oxford         |   |-- outline.doc         |   |-- programming         |   |   `-- report.pdf         |   `-- security         `-- stenton             |-- gen_ed             `-- lib_arts                 |-- english.txt                 `-- match.doc  15 directories, 11 files  I tried doing the command: $ cp ../cambridge/security/parking ./parking2  ...but it isn't working. The question in the image above states that the current directory is stenton, and that we need to make a copy of the file named parking (from the security directory), and to name the new file parking2, and place it in the current directory, stenton, using relative pathnames. What am I doing wrong? My cp command seems to be correct. How do I restore a Places folder I accidentally deleted in Nautilus? I accidentally deleted my Documents folder and didn't notice it for a couple days. Somewhere in that time, Nautilus auto-updated my list of Places so it no longer includes my Documents folder. I have since restored my Documents folder, but the Places link is still missing. How do I get it back? Short story in book collection about war machines and armies out of control I read in an anthology book in 1975. It starts with two people watching a “robot” plane glide high and then dive into an opening of a factory causing a massive explosion. I’m not sure but I think the people may have orchestrated the attack on purpose to get the robot armies fighting each other in the hope that it would diminish robot army capabilities and bring them under control. The robot wars did occur, but at the end of the story the people discover a tube sticking out of the ground that is periodically shooting something into the air. Nearby they find a canister that did not get launched out of the “cannon” successfully and it was broken open. After close examination they discover tiny “ants” on the canister that are actually tiny robots which are rebuilding the robot war factories. The robots have adapted and will keep trying to fulfill their mission. This story may  have been in a booked edited by Roger Elwood, but I cannot guarantee it. How do I keep both the background and foreground in the image in focus at the same time? How do you have both the background and foreground in the image in focus at the same time?  Last week I was attempting a shot where I had the back of a hat in focus and in the distance you could see a mountain. I wanted both in focus, but could either focus on the mountain or the hat. I ended up taking the in-focus shots of both and merging them in Photoshop. While that isn't difficult I would prefer to shoot the shot as accurate as possible. From what I have read aperture is important in the depth of field but what are the techniques for keeping both the background and foreground in focus?  I am using a Nikon D5100 with a 18-55mm f/3.5-5.6 (standard kit lens) and a 55-200mm  f/4.5-5.6.    almost answers my question, but I am a bit confused. Can someone explain this a bit differently? Thanks! I want to find an example of a homomorphism $f:G\to H$ such that $A$ is a normal subgroup of $G,$ but $f(A)$ is not so in $H.$  I know that if $f$ was onto $f(A )$ must be normal , but otherwise i want to find an example! Baryons have charges that are the result of a polynomial calculation of their building blocks (quarks)'s fractional charges. But what gives these quarks electric charges? What interactions do they have with photons? And what about leptons, like muons and electrons? How do they get their -1 charge? And then, how do positrons and anti-muons get +1 charge? Same goes for quarks: how does up-antiquarks get -2/3 charge? Or I may want to formulate my question this way:  How does any elementary particle interact with the EM-Force to get an electric charge? Estimating the integrated Tchebychev function and calculating its error Do newer laptop batteries still need to be drained before recharging? 10 years ago when I was doing hardware support it was best practice to fully drain a laptop battery prior to recharging in order to maximize its life.  Is this still the case or can a battery now be recharged at any point without worrying about shortening the lifespan? Ubuntu 14.04 LTS live USB boot error (gfxboot.c32:not a valid COM32R image) Version tags reloaded I'm getting sick of version numbers in tag names (aka version tags). Look,      I just want them all to be just . They are all about JSF. I browse and answer questions about JSF. I don't want to browse in all those different tags. I don't want gold badges for both  and . I can't hammer a duplicate  question because I don't have a gold badge for that. Across years I observed that a version tag is usually only picked by the asker when a &quot;relatively new&quot; or &quot;relatively old&quot; version is being treated in the question. When the &quot;currently mainstream&quot; version is being treated,  or when the asker is &quot;more proficient&quot; in the language, then askers often just pick the versionless . While moving in time, this may cause confusion by future readers when the version isn't explicitly specified anywhere in the question. I try to maintain them by adding/removing the version tag depending on its relevance, and by adding the versionless tag when it's absent. It only feels a neverending story. I'm sure other tag caretakers also have mixed feelings on this. I propose to normalize the version from the tag name:  Ban version numbers in tag names in the model (not in the UI). Add an optional single-choice version field to the Tag entity in the model. Users with edit privileges (no suggested edits please) must be able to change versions. Users with gold tagbadges must be able to add and edit versions. I'd imagine the version edit thing to be reachable via that tag info popover (when you hover the tag). Tags themselves however should look exactly the same, the version just separated with e.g. a hyphen from the tag name.  When in place, migration of existing version tags should be piece of cake. There's apparently already a script in place which recognizes version tags, it could be reused to re-match current tags and extract the version from it into the new version field. The alternative would be to automatically add the versionless tag when a version tag is being used. But this is IMO only tag pollution.  I'm posting this on meta.se instead of meta.so because version numbers aren't only on SO a problem, but on basically all HW/SW related sites. Is there a way to call process builder from Apex? What are the most important things I need to do to encourage Google Sitelinks? Subgroups of $\Bbb{R}^n$ that are closed and discrete Performing deep learning land cover classification using R? I am really new to Deep Learning and, unfortunately, I can't find example codes on land cover classification other than  where the author wrote a script in R for a large dataset.   The main reason that I am asking is because recently I found a few papers on Remote Sensing Image classification using Deep Learning and I was wondering if there were any R examples on that subject.  So, is there a code example, preferably a step-by-step, which I can use?  I found several git repos like  that can do Deep Learning classification with R, BUTT, I am still looking for a simple multi-spectral image segmentation method. An example of that can be found at  and I also found a similar question in  for which the answer is "use something else other than R if you can".  If I find anything that works today I will be posting a working answer. Is the consciousness currently in oneself the same the the consciousness that used to be or in the future will be in oneself? People seem to believe that one's consciousness is a "different" consciousness than that of others, but the "same" consciousness as the one that has been in one's body in the past and the one that will be in one's body in the future. How likely is this to be true and why?   Also, I have almost no knowledge about neuroscience, so please refrain from using neuroscience jargon if feasible. Is there a way to have a copy of any message sent from a Gmail account sent to another address?  I've got any messages coming to my address copied to another (see  for one solution, setting up filters is another), but I haven't yet found a way to have outbound messages automatically copied.  Is there a way?