slug Django field; do we need this?
What is a "slug" in Django?
What is this icon depicting a phone and Wi-Fi together? Will running a large query on a secondary database in an availability group affect transaction performance in the primary database? I need to provide real-time, or almost real-time, data for SSRS and Tableau reporting. I don't want the production OLTP system to be negatively impacted by long running queries. Will running a large query on a secondary database in an availability group affect transaction performance in the primary database? I try to understand and visualize myself covariance matrix. Supposing I have a matrix A = [ 2 3 4; 5 5 6 ], how do I calculate its covariance matrix, and what is its practical meaning? (All I was able to understand by now is that on the diagonal of the covariance matrix, variances for particular variables are placed, and on the upper and lower fields correlations between those variables.) How do I select all but two types of entities in Minecraft with the type selector? The ring $ℤ/nℤ$ is a field if and only if $n$ is prime Let $n \in ℕ$. Show that the ring $ℤ/nℤ$ is a field if and only if $n$   is prime.   Let $n$ prime. I need to show that if $\bar{a} \neq 0$ then $∃\bar b: \bar{a} \cdot \bar{b} = \bar{1}$. Any hints for this ?  Suppose $ℤ/nℤ$ is a field. Therefore: for every $\bar{a} \neq 0$ $∃\bar b: \bar{a}\cdot \bar{b}=1$. How can I show that $n$ must be prime ? How can I run ssh-add automatically, without a password prompt? I want to communicate between several computers on my network (static Ethernet), through SSH. In order to do that I need to run ssh-add every time I log in on a specific machine, how can I do it so that it's set up once and it doesn't ask me for the passphrase every time I log in or reboot my machine?  I know that there is a way that you should add some lines to the bash_profile file, but I still need to type the password every time I reboot/log in to a specific machine.  if [ -z "$SSH_AUTH_SOCK" ] ; then     eval `ssh-agent -s`     ssh-add fi Sort Order on the User Filter is Surprising To Me When filling in the "Type to Find Users" , it seems to sort by exact match and then by reputation when I am on the reputation tab.   For example, please consider the following search results:    This threw me off since I thought that the sort order is reputation. I guess this often might give people what they want, but when picking a popular name is shows a lot of 0 rep users. Maybe adding a filter for low rep to the exact match might give more expected results, or just sorting on Rep? Showing that $\frac{z^n}{1+z^{2n}}$ is real for $|z|=1$. How to correctly add a path to PATH? I'm wondering where a new path has to be added to the PATH environment variable. I know this can be accomplished by editing .bashrc (for example), but it's not clear how to do this.  This way:  export PATH=~/opt/bin:$PATH   or this?    export PATH=$PATH:~/opt/bin Is there any hint that the MoM or anywhere else got support in combating voldemort the first time around? Or is everything completely UK-centric?  I can't remember anyone in the second war being specifically sent from europe to help, even though we see international wizards in book 4. But I don't think all the events of the first war are covered in the books.  So are other bodies like the MoM involved in the first war, or was it isolated in the UK? When I'm viewing a user profile, it's more often than not to gauge this user within the community. How long they have been a member, how active they have been, when was their last activity and of course, what content are they contributing. This is accentuated when the user in question is a relatively new user. I would want to know this in order to make my response or comment more informative and to not be too harsh on inexperienced users.  One good measure I use to identify a new user is their join date. I would like to request that the "member for" field be added to the profile page for users on the mobile application just as it is when viewing the desktop version.  The "last seen" field would also be useful. It's useful to me on the desktop version to know more or less when/if to expect a response from a user after leaving them a comment/answer. It would useful on the mobile version for the same reasons.    I just realized that this information is available on the mobile version of the webiste. If it was decided that this information is important enough to also appear on the mobile web version, why not include it on the native mobile applications? Why does Java's hashCode() in String use 31 as a multiplier? Per the Java documentation, the  for a String object is computed as:   s[0]*31^(n-1) + s[1]*31^(n-2) + ... + s[n-1]       using int arithmetic, where s[i] is the    ith character of the string, n is the length of    the string, and ^ indicates exponentiation.   Why is 31 used as a multiplier?  I understand that the multiplier should be a relatively large prime number. So why not 29, or 37, or even 97? Why do I have blurred vision and how do I fix it? How do I disable client side decoration globally in GNOME? I'm using Ubuntu GNOME 17.04. One encounters client side decoration (CSD) as most of the official GNOME applications (Nautilus, gedit, Evince etc.) use  (a combined title bar and toolbar, see linked screenshots) whereas other applications don't. This feature is disabled in Unity, all the applications use traditional separate title bars.  Screenshots (from ):     Nautilus with GtkHeaderBar   Nautilus without GtkHeaderBar     For consistency I want to disable GtkHeaderBars globally (in all the applications using it) and use separate title bars. Is there a way to achieve that?  I have heard of gtk3-nocsd package, but couldn't make it work with GNOME for all the applications. How can I convert from hex to base64? Can anyone recommend a straightforward way/tool to convert hex to base64?  I'm using Linux and OS X. When given $p = 5, q = 11, N = 55$ and $e = 17$, I'm trying to compute the RSA private key $d$.  I can calculate $\varphi(N) = 40$, but my lecturer then says to use the extended Euclidean algorithm to compute $d$. That's where I get stuck.    Here's my work so far:  First I use the Euclid algorithm to calculate:  40 = 2(17) + 6  17 = 2(6) + 5 6 = 1(5) + 1 = gcd   So I know the GCD is 1. Applying the 'extended' section of the algorithm:  6 = 40-2(17) 5 = 17-2(6) 1 = 6-1(5) 1 = 6-1(17-2(6)) 3(6) = 1 (17) 3(40 - 2(17)) - 1(17) 3(40) - 3(17)   I know the answer is $33$, but I have no idea how to get there using the extended Euclidean algorithm. I can't figure out why I'm getting $3(40) - 3(17)$ when I know the answer should contain $33$. Looking for the title of a book about alien invasion, mining asteroids and using lasers to defend earth What I remember of this novel/series is that the main character creates solar laser satellites and mines asteroids to create more satellites to defend Earth from aliens. Later on, he uses the hollowed out asteroids as a base and eventually as an armored fortress to repulse the alien fleets. I last remember the main character attempting to hollow out more asteroids to defend and attack the aliens eventually. Would the One Ring even work for anyone but Sauron? I tried to find a topic here on this (possible problem) but I didn't.   I reported it at  but Tim Hoffmann pointed me that it is not a problem of editor. After tested with nano and pdflatex I'm posting here.  The minimal code produces errors. OK, we can solve it using \\{}.   But is this a problem with TeXlive 2014 or there are some good reasons to have that behavior.  \documentclass{report} \begin{document} test\\ [foo]  test\linebreak [foo]  test\newline [foo] \end{document}      ! Missing number, treated as zero.                        f l.3 test\ [foo] How to prevent Google from finding my admin index page?