Harry is a half-blood and Ginny is a pure-blood, so what does that make his children? I've been told it means they are pure-bloods but I can't be sure. What do you think?
I was checking on something in the Harry Potter wiki and saw Harry listed as "Half-Blood."  Both his parents were magical, but, as we know, his grandparents on his Mother's side were muggles.  This reminds me of the racially loaded terms like octoroon.  (In the south, you still hear those terms every once in a while.)  When there was still segregation, having only 1 great-grandparent of an ethnic group was enough to classify a person of that group.  So how far down the line did it go in the Harry Potter universe?  Just how many generations removed from a muggle-born would a person have to be before they're no longer classified as half-blood or something similar?
I have been thinking about the following formulation of the Axiom of Choice.:     For any relation $R$, there is a function $H$, which is a subset of $R$, and such that $\operatorname{dmn}H=\operatorname{dmn}R$.   At first, it seemed surprising to me that this did not follow from Comprehension (i.e., from the schema  $\forall x_1, x_2, ..., x_n \forall C\exists B \forall x ( x \in B \Leftrightarrow x \in C \land \phi )$, where $B$ does not occur free in $\phi$).    I thought that for any relation, it seems that we should be able to define a subset of it with the same domain meeting a "functional condition".  But when I tried to do this, I couldn't.  However, I felt like I was getting close when I let $B$ be free in $\phi$, i.e., when I let myself say that $w$ is in $R$ and also anything in $H$ meets such and such conditions, where $H$ is the set (function) whose existence I'm trying to prove.    But my understanding is that Choice does not even follow from Naive Comprehension.  So, I wondered if someone could explain the following precisely.   Why does the above formulation of Choice does not follow from regular Comprehension? Why does it not even follow from Naive Comprehension (assuming that it does not)? Catching poisoned arrows When catching an arrow tipped with poison (like the ones used by yuan-ti) with an ability like the one the monk has or the one given by arrow catching gloves: does the ability reduce the poison damage? If so, is the total damage or the piercing one caused by the arrow only the damage that must be downed to 0 to catch the missile? Highlighting the selected tab using jQueryUI Tabs I have a header page with links to all the visualforce page as tabs.I need to highlight the tab on select of it.      &lt;apex:page title="{!$Label.site.site_login}" showHeader="false" sidebar="false"       standardStylesheets="false"&gt; &lt;apex:includeScript value="{!URLFOR($Resource.jQuery, '/js/jquery-1.4.2.min.js')}"  /&gt;   &lt;apex:includeScript value="{!URLFOR($Resource.jQuery, '/js/jquery-ui-1.8.6.custom.min.js')}"  /&gt; &lt;apex:stylesheet value="{!URLFOR($Resource.jQuery, '/css/ui-lightness/jquery-ui-1.8.6.custom.css')}"  /&gt;          &lt;html lang="en"&gt;  &lt;head&gt;   &lt;script src="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/jquery-ui.min.js"&gt;  $(function()  {   $( "#tabs" ).tabs();   });  &lt;/script&gt;   &lt;style&gt;   #tabs .ui-tabs-active    { background: red; }  &lt;/style&gt;     &lt;/head&gt;      &lt;body&gt;         &lt;nav class="navbar navbar-static-top navbar-inverse" role="navigation"&gt;             &lt;div class="container"&gt;                 &lt;div class="navbar-header"&gt;                     &lt;button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-ex1-collapse"&gt;                         &lt;span class="icon-bar"&gt;&lt;/span&gt;&lt;span class="icon-bar"&gt;&lt;/span&gt;                         &lt;span class="icon-bar"&gt;&lt;/span&gt;                      &lt;/button&gt;                     &lt;a class="navbar-brand" style="line-height: 0px; padding: 10px 15px;" href="index.php.html"&gt;                         &lt;img height="30px" src="{!URLFOR($Resource.Resources, 'img/logo.png ')}" /&gt;                     &lt;/a&gt;                 &lt;/div&gt;                 &lt;div class="collapse navbar-collapse navbar-ex1-collapse" id="tabs"&gt;                     &lt;ul class="nav navbar-nav"&gt;                         &lt;li id="Home"&gt;                             &lt;apex:outputLink value="{!$Page.Home}"&gt;Home&lt;/apex:outputLink&gt;                         &lt;/li&gt;                         &lt;li id="chatter"&gt;                             &lt;apex:outputLink value="{!$Page.Chatter}"&gt;Chatter&lt;/apex:outputLink&gt;                         &lt;/li&gt;                         &lt;li id="page3"&gt;                             &lt;apex:outputLink value="{!$Page.page3}"&gt;Room&lt;/apex:outputLink&gt;                         &lt;/li&gt;                         &lt;li id="page4"&gt;                             &lt;apex:outputLink value="{!$Page.page4}"&gt;Page4&lt;/apex:outputLink&gt;                         &lt;/li&gt;                     &lt;/ul&gt;                 &lt;/div&gt;             &lt;/div&gt;         &lt;/nav&gt;     &lt;/body&gt;      &lt;/html&gt; &lt;/apex:page&gt; Code Formating in Comments Mean Time to Failure (MTTF): When disk manufacturers post this, how should you interpret their numbers? Mean Time to Failure (MTTF) is usually given in terms of hours, and by doing some calculations, it seems that a disk should fail only after a good number of years have gone by.  It seems that disks need repair more often than that. Does anyone know why this is so?  I figured that there is something fishy about this metric. Am interpreting something wrong here? error when adding user to wheel group in CentOS 7 I am trying to grant sudo privileges to a user of a CentOS 7 devbox by typing gpasswd -a user wheel, but the attempt is failing.  What am I doing wrong?    Here is what I typed:    I discovered that the user is not in the wheel group as follows:    [user@localhost git]$ sudo yum install git [sudo] password for user:  Sorry, try again. [sudo] password for user:  Sorry, try again. [sudo] password for user:  user is not in the sudoers file.  This incident will be reported.   I then logged in as root and typed the following to add the user to the wheel group:    [user@localhost git]$ su - Password:  Last login: Thu Aug 20 17:11:31 PDT 2015 on pts/0 [root@localhost ~]# gpasswd -a user wheel Adding user user to group wheel [root@localhost ~]# exit logout   I finally tried to use the sudo command again but it failed as follows:    [user@localhost git]$ sudo yum install git [sudo] password for user:  user is not in the sudoers file.  This incident will be reported. [user@localhost git]$ Is there a 'rule of thumb' that I can use to estimate depth of field while shooting? I can use a DoF calculator, or crunch the heavy math by hand if I really want to know exactly what my DoF is going to be... but most of the time knowing exactly is actually overkill, and taking the time to pull out a DoF calculator is impractical. I'm wondering if anyone knows of a 'rule of thumb' that is common for quickly figuring out a rough estimate of what my DoF will be when I'm in the field... ZF: Difference between POW and SEP? If electrons were positive and protons were negative, would life be different? I did a fresh install of Ubuntu 16.04. /dev/md1 contains an ext4 filesystem that is mounted at /:  /dev/md1 on / type ext4 (rw,relatime,data=ordered)   Now I want to set the automatic filesystem check interval to one month, but I'm getting a strange error that I find no useful information about:  &gt; tune2fs -i 1m /dev/md1 tune2fs 1.42.13 (17-May-2015) tune2fs: Filesystem has unsupported read-only feature(s) while trying to open /dev/md1 Couldn't find valid filesystem superblock.   Rebooting didn't help. On another machine running Ubuntu 12.04, the same command works like a charm.  Does anyone have an idea what's wrong?  The command tune2fs -l /dev/md1 works fine, by the way. Here is its output:  tune2fs 1.42.13 (17-May-2015) Filesystem volume name:   &lt;none&gt; Last mounted on:          / Filesystem UUID:          38366a40-bbe1-476b-acfe-d271be6335eb Filesystem magic number:  0xEF53 Filesystem revision #:    1 (dynamic) Filesystem features:      has_journal ext_attr resize_inode dir_index filetype needs_recovery extent 64bit flex_bg sparse_super large_file huge_file dir_nlink extra_isize metadata_csum Filesystem flags:         signed_directory_hash Default mount options:    user_xattr acl Filesystem state:         clean Errors behavior:          Continue Filesystem OS type:       Linux Inode count:              8380416 Block count:              33521664 Reserved block count:     1676083 Free blocks:              32419430 Free inodes:              8312762 First block:              0 Block size:               4096 Fragment size:            4096 Group descriptor size:    64 Reserved GDT blocks:      1024 Blocks per group:         32768 Fragments per group:      32768 Inodes per group:         8192 Inode blocks per group:   512 Flex block group size:    16 Filesystem created:       Thu May 31 10:01:27 2018 Last mount time:          Thu May 31 10:49:41 2018 Last write time:          Thu May 31 10:15:14 2018 Mount count:              7 Maximum mount count:      -1 Last checked:             Thu May 31 10:01:27 2018 Check interval:           0 (&lt;none&gt;) Lifetime writes:          5782 MB Reserved blocks uid:      0 (user root) Reserved blocks gid:      0 (group root) First inode:              11 Inode size:               256 Required extra isize:     32 Desired extra isize:      32 Journal inode:            8 First orphan inode:       4325378 Default directory hash:   half_md4 Directory Hash Seed:      9d55d989-2c2b-4ad8-a29e-53c8798ec68e Journal backup:           inode blocks Checksum:                 0x3d9f8d23 Cancel/kill window.setTimeout() before it happens I have a few places where I use the line below to clear out a status, for example.  I have a few of these that hang out for 10 seconds or more and if the user gets clicking around the action can occur at incorrect time intervals.  window.setTimeout(function() { removeStatusIndicator(); }, statusTimeout);   Is it possible to cancel or kill this with some jQuery or JavaScript code, so I don't have this process hanging around? Why does my item name not show up in 1.13? I am in 1.13 Pre-Release 7 trying to make a one command creation and I need an item with a specific name. The command I use is /give @p diamond_sword{display:{Name:"Sword of Power"}} and it gives my a diamond sword, but it doesn't have the name.   This is me running the command.   This is the command not working. $\epsilon$ undefined using Minion Pro with pdftex I'm using MiKTeX 2.9 and have recently installed the Minion Pro fonts for use with pdftex. I followed the instructions available on  to install them.  Everything works as expected, but in place of the Greek letter epsilon I get a box with a cross (see below), and the following warning:    I found the issue was reported , but I still can't fix it. xelatex works fine, but I'd like to to stick to pdftex so I can use microtype.  \documentclass{article}  \usepackage[T1]{fontenc} \usepackage{MinionPro}  \begin{document}  Text here. $\epsilon$  \end{document}       UPDATE: a set of instructions for the installation of the up-to-date FontPro scripts with MiKTeX can be found . How to text-to-speech output using command-line? How to get speech output from entered text by using command-line?  Also facility to change speech rate, pitch, volume etc using simple command. List files sorted by the number of lines they contain How can I list the number of lines in the files in /group/book/four/word, sorted by the number of lines they contain?   ls -l command lists them down but does not sort them JUnit Testing Exceptions Hard disk file system is shown as Raw file system; how can I access it? Can I have 8 GB RAM on 32-bit Win 7? Possible Duplicate:             According to , Win 7 only supports 4 GB of RAM. I, however have been reading some forums and some say they are using 8 GB RAM with good performance. I am wondering if I can use 8 GB before I purchase. Flip x and y axes in Excel graph This should not be very difficult, but I cannot figure out how to do it.  I have a table similar to this     %low %high  0   0   12  1  13   26  ... 19  90   94 20  95  100   When I graph it, excel defaults to having the first column on the x axis and plotting the second and third column as y values. I want the first column to be on the y axis instead. I assume there is an easy way to do this, but I cannot figure it out. Most of the things I have found from searching have suggested the "Switch Row/Column" button, but that does something else.  Thanks for the help. $$\int x^3\sqrt{4-x^2}dx$$ I tried changing the expression like this: $$\int x^3\sqrt{2^2-x^2}dx=\int x^3\sqrt{(2-x)(2+x)}dx$$ And that's where I got stuck. I tried integration by parts but it doesn't simplify the expression.