Are gravitational waves subject to gravitational lensing?
Do gravitational lenses work on gravitational waves?
Under Windows 7, how can I delete a folder whose name ends with "..."? How to "cat" or "less" a libreoffice writer .odt file? I know that the Windows copy dialog (in Windows&nbsp;XP) stores the copy in memory first, and it is still copying after the dialog closes, so the time is off, but why is the estimation of the time it will take to make a copy so inaccurate, even when memory copying has been disabled (in Vista and Windows&nbsp;7)? It seems so arbitrary! How does the whole copy procedure work, and why can't Windows estimate it correctly? Standalone python app that uses qgis.core without installing qgis So many interesting questions get asked on Stack Overflow and then immediately closed (or worse yet, closed and re-opened for days on end) because they're subjective, argumentative, and fundamentally unanswerable due to our lack of omniscience: without the ability to see into the future and/or know the secret motivations of companies and their developers, we are left to make wildly varying (un)informed guesses. The obvious solution to this is to add a  feature to the Ask a Question page. Similar to the current &quot;Related Questions&quot; feature, this could be used to answer otherwise-unanswerable questions before they're asked, thus saving everyone time and frustration. I propose a simple system whereby a web cam is aimed at an ordinary  device, long recognized as one of the most accessible and accurate fortune-telling mechanisms available to modern society. A simple  could be placed under this rig and triggered in response to the user's typing. Once focus leaves the Title input field, a short delay will be triggered, followed by a bit of logic to capture the 8-ball's result and feed it through a simple OCR routine to produce the result.  So far as I'm aware, SO would be the first major Q&amp;A site to implement such a feature...  Examples:            ...another UV resurrection... link new object to scene with python in 2.8 How can I return to the start of a line in a console? How can I return to the start of a line and overwrite what has already been output on the console? The following does not appear to work:  System.out.print(mystuff+'\r'); Can a .NET windows application be compressed into a single .exe? How do I show apt-get package management history via command line? Is there a way to show the history of packages that were changed by apt-get via command line? Probably dumb question, but I would like to ask it anyway.  I was to solve this equation:  $z^4 = -16$  At first glance, the way to solve it would be (as any other equation):  $z^2 = \sqrt{-1} * 4 \lor z^2 = -\sqrt{-1} * 4$  $z^2 = 4i \lor z^2 = -4i$  $z = 2\sqrt{i} \lor z = -2\sqrt{i} \lor z = 2i\sqrt{i} \lor z = -2i\sqrt{i}$  However, in suggested answers, there are $z_1, z_2, z_3$ and $z_4$ found using trigonometric formulas. Is there something particulary wrong in my solution and the only proper one uses trigonometric form of complex number? Misplaced navigation bar and question title It appears that on Server Fault and Super User, the navigation bar and question title have suddenly become misplaced. The same does not occur on SO and mSO, nor on any of the other SE sites I spot-checked.  This is being seen in both Chrome and Firefox and just began occurring within the last few minutes.      What it should look like:      While this was fixed for a few hours, it has returned as of 22:05. past simple or present perfect I'm a C++ newbie, but I wasn't able to find the answer to this (most likely trivial) question online.  I am having some trouble compiling some code where two classes include each other.  To begin, should my #include statements go inside or outside of my macros?  In practice, this hasn't seemed to matter.  However, in this particular case, I am having trouble.  Putting the #include statements outside of the macros causes the compiler to recurse and gives me "#include nested too deeply" errors.  This seems to makes sense to me since neither class has been fully defined before #include has been invoked.  However, strangely, when I try to put them inside, I am unable to declare a type of one of the classes, for it is not recognized.  Here is, in essence, what I'm trying to compile:  A.h  #ifndef A_H_ #define A_H_  #include "B.h"  class A {     private:         B b;      public:         A() : b(*this) {} };  #endif /*A_H_*/   B.h  #ifndef B_H_ #define B_H_  #include "A.h"  class B {     private:             A&amp; a;      public:         B(A&amp; a) : a(a) {}  };  #endif /*B_H_*/   main.cpp  #include "A.h"  int main() {     A a; }   If it makes a difference, I am using g++ 4.3.2.  And just to be clear, in general, where should #include statements go?  I have always seen them go outside of the macros, but the scenario I described clearly seems to break this principle.  Thanks to any helpers in advance!  Please allow me to clarify my intent if I have made any silly mistakes! Is there a system in place to prevent new users asking, answering and accepting answers to each others' off-topic questions? Getting the class name of an instance? I  and while on other sites I did not get a 'Reputation Notification' to explain that I was given 2 upvotes for my answer - yet if I manually check my Profile here at meta.SE my total Reputation is in agreement with the amount there.  I'm not knowledgeable about the intercommunication between the servers and sites but I would explain it this way: Super User either failed to send or other sites failed to receive the message the I had a reputation update on Super User.  I should have received either two green star trophies (🏆) of 10 reputation each or one of 20; depending on when I returned to one of the Stack Exchange / Stack Overflow / Super User / etc. sites.  Here's a screenshot showing no reputation change notification for Super User:    Here's a screenshot of my Profile over at Super User showing that I was silently credited:    I'm bringing this up on Meta.SE in case the communication is broken between more sites than just Super User and everywhere else. How can I launch screensaver with a keyboard shortcut? How to find a function in $ L_{2}(0,\infty)$ but not $L_{q}(0,\infty)$, $q\neq 2 $ Flowchart using Tikz I'm trying to create a fine flowchart that is a bit complicated. Therefore I need a block for a predefined process and a connector block as well as a data block. Can someone help me? In comment is what I'd like to see in my code to keep my code nicely arranged. The rest of the code is a simple example for the Tikz site.  \documentclass{article}  \usepackage[latin1]{inputenc} \usepackage{tikz} \usetikzlibrary{shapes,arrows} \begin{document} \pagestyle{empty}   % Define block styles \tikzstyle{decision} = [diamond, draw, fill=blue!20,      text width=4.5em, text badly centered, node distance=3cm, inner sep=0pt] \tikzstyle{block} = [rectangle, draw, fill=blue!20,      text width=5em, text centered, rounded corners, minimum height=4em] \tikzstyle{line} = [draw, -latex'] \tikzstyle{cloud} = [draw, ellipse,fill=red!20, node distance=3cm,     minimum height=2em]  %\tikzstyle{subroutine} = [draw,rectangle split, rectangle split         horizontal,rectangle split parts=3,minimum height=1cm]  %\tikzstyle{connector} = [draw,circle,...] %\tikzstyle{data} = [draw, trapezium, ...]  \begin{tikzpicture}[node distance = 2cm, auto]     % Place nodes     \node [block] (init) {initialize model};     \node [cloud, left of=init] (expert) {expert};     \node [cloud, right of=init] (system) {system};     \node [block, below of=init] (identify) {identify candidate models};     \node [block, below of=identify] (evaluate) {evaluate candidate models};     \node [block, left of=evaluate, node distance=3cm] (update) {update     model};     \node [decision, below of=evaluate] (decide) {is best candidate     better?};     \node [block, below of=decide, node distance=3cm] (stop) {stop};     % Draw edges     \path [line] (init) -- (identify);     \path [line] (identify) -- (evaluate);     \path [line] (evaluate) -- (decide);     \path [line] (decide) -| node [near start] {yes} (update);     \path [line] (update) |- (identify);     \path [line] (decide) -- node {no}(stop);     \path [line,dashed] (expert) -- (init);     \path [line,dashed] (system) -- (init);     \path [line,dashed] (system) |- (evaluate); \end{tikzpicture}   \end{document} At work we are being asked to create XML files to pass data to another offline application that will then create a second XML file to pass back in order to update some of our data. During the process we have been discussing with the team of the other application about the structure of the XML file.   The sample I came up with is essentially something like:  &lt;INVENTORY&gt;    &lt;ITEM serialNumber="something" location="something" barcode="something"&gt;       &lt;TYPE modelNumber="something" vendor="something"/&gt;     &lt;/ITEM&gt; &lt;/INVENTORY&gt;   The other team said that this was not industry standard and that attributes should only be used for meta data. They suggested:  &lt;INVENTORY&gt;    &lt;ITEM&gt;       &lt;SERIALNUMBER&gt;something&lt;/SERIALNUMBER&gt;       &lt;LOCATION&gt;something&lt;/LOCATION&gt;       &lt;BARCODE&gt;something&lt;/BARCODE&gt;       &lt;TYPE&gt;          &lt;MODELNUMBER&gt;something&lt;/MODELNUMBER&gt;          &lt;VENDOR&gt;something&lt;/VENDOR&gt;       &lt;/TYPE&gt;    &lt;/ITEM&gt; &lt;/INVENTORY&gt;   The reason I suggested the first is that the size of the file created is much smaller. There will be roughly 80000 items that will be in the file during transfer. Their suggestion in reality turns out to be three times larger than the one I suggested. I searched for the mysterious "Industry Standard" that was mentioned, but the closest I could find was that XML attributes should only be used for meta data, but said the debate was about what was actually meta data.  After the long winded explanation (sorry) how do you determine what is meta data, and when designing the structure of an XML document how should you decide when to use an attribute or an element?