From some answers regarding LastActivityDate, I know that LastActivityDate of a question considers:  a) Posting a question,  b) Answering a question,  c) Edits to either question or answer(s)  I want to know if LastActivityDate of a question from Posts.xml considers the following scenarios:  a) Comment on a question,  b) Comment on any answer of a question,  c) Vote (upvote/downvote) to a question,  d) Vote (upvote/downvote) to any answer of a question,  e) Upvote to any comment on a question or any answer of a question?
What can cause a question to be "bumped" to the first page in the Active tab of a Stack Exchange site? (Changing the "Last Active" date.)  .
Are GUID collisions possible? I'm working on a database in SQL Server 2000 that uses a GUID for each user that uses the app it's tied to. Somehow, two users ended up with the same GUID. I know that microsoft uses an algorithm to generate a random GUID that has an extremely low chance of causing collisons, but is a collision still possible? Is an increasing union of subspaces a subspace? What is the Fastest a Character Can Move in One Turn? At level 20 with any magic items in the DMG, and any spells, what is the fastest a DnD 5e character could move using their movement?  (i.e., not including teleportation) Can you cast a spell learned from the Magic Initiate feat using spell slots? Say I play a wizard who learns cure wounds by taking the Magic Initiate feat. Could I cast that spell using the Wizard's spell slots? I have this picture:  (I have the original in Pixen and could export it to several different formats. I went with PNG though since it's lossless.)  When I open my picture in Preview (OS X) and zoom in, it looks fine. The characters have extremely sharp boarders between them and the background. However, when I put it into my LaTeX document, compile it to a PDF (using TeXShop) and then zoom in, it suddenly have gotten blurry (see screenshot: ).  Minimal working example:  \documentclass[12pt]{article} \usepackage{graphicx} \begin{document} \includegraphics[scale=1]{fig1.png} \end{document}   In the end, I would like to be able to scale the picture freely without there being any blurring at all. Adding coordinate system to layout in QGIS composer? What is the best way to sort the results of a sql query into a random order within a stored procedure? Which manuals are on your "TeX Reference" shelf? This is a community wiki since there is no "one true answer"- if you find an answer that contains a lot of your choices, but is missing something you feel is incredibly useful.  Feel free to add it.  A short description of what topics the reference covers would be nice as well.  Organize by subject please.  For example: I always keep the following PDFs at my fingertips.  Document Layout   :  Covers, in exquisite detail, how to produce just about any document using the memoir LaTeX class. ( 4.5 MB)   Mathematical Typesetting   : A document by Herbert Voß that explains how to typeset just about any mathematical expression in LaTeX. ( 2 MB)   Graphics   : Explains, with examples, how to draw just about any figure using PGF/TikZ.  Also a good example of what awesome documentation should look like. ( 9.5 MB) Find a parabola touches the line $y=x$ and $y=-x$ at $A(3,3)$ and $B(1,-1)$ If a parabola touches the line $y=x$ and $y=-x$ at $A(3,3)$ and $B(1,-1)$, then find the focus, axis of the parabola and its directrix.   What I thought: Since the 2 tangents are perpendicular,the origin must lie on the directrix and the line joining A and B is a focal chord. Don't know how to proceed from here.. Why the switch statement cannot be applied on strings? Compiling the following code and got the error of type illegal.  int main() {     // Compilation error - switch expression of type illegal     switch(std::string("raj"))     {     case"sda":     } }   You cannot use string in either switch or case. Why? Is there any solution that works nicely to support logic similar to switch on strings? Reprojecting raster from lat/lon to UTM in R? What's the easiest way to run GUI apps on Windows Subsystem for Linux as of 2018? I searched around, and currently there are two methods suggested; installing an enhancement for Windows Subsystem for Linux and installing an XServer.  I want to know which method is the most hassle-free (easy to install AND to use), and which one is less memory-heavy.  I just want Synaptic and CMake. Why couldn't that be a builtin feature? How to Edit PDFs? Show that $\int_{0}^{1}\{P(x)\}^{2}\,dx = (n + 1)^{2}\left(\int_{0}^{1}P(x)\,dx\right)^{2}$ About the localization of a UFD I was wondering, is the localization of a UFD also a UFD?    How would one go about proving this? It seems like it would be kind of messy to prove if it is true.  If it is not true, what about localizing at a prime? Or what if the UFD is Noetherian? Answering a phone call with "Yes, XX, tell me" I have heard a lot of people pick their phone and go "Yes, XX, tell me" (highly used in India).  I think the right way should be "Hey, XX, what's up?" or "Hey, XX, what's going on"? But does this work in a professional environment? How to select all faces with the same material? Let n be an even integer. How many different ways can I choose subsets of the set {1,2...,n} I am trying to find the equation of characteristic curves and solution of the partial differential equation $$x\frac{\partial u}{\partial y}-y\frac{\partial u}{\partial x}=u$$ $u(x,0)=\sin(\frac{\pi}{4}x)$ .   What I did: $$\frac{dx}{-y}=\frac{dy}{x}=\frac{du}{u}$$ with  From first two equalities $$\frac{dx}{-y}=\frac{dy}{x}$$ by solving we get $x^2+y^2=c_1$ for some constant $c_1$. Now I am stuck with the third and rest of the equalities to come up with a suitable manipulation to solve the problem. How can I do this? Any help would be great. Thanks. What is the limit of:  $$\lim_{n\to \infty} \frac{n^1+\dots+n^n}{1^n+\dots+n^n} = ?$$  I did some computation with big numbers, I guess it is in the interval $\left(\frac{1}{2},1\right)$.