Network connection is lost after every few minutes
Wireless connection fails every few minutes
What is the C# equivalent of NaN or IsNumeric? What is the most efficient way of testing an input string whether it contains a numeric value (or conversely Not A Number)? I guess I can use Double.Parse or a regex (see below) but I was wondering if there is some built in way to do this, such as javascript's NaN() or IsNumeric() (was that VB, I can't remember?).  public static bool IsNumeric(this string value) {     return Regex.IsMatch(value, "^\\d+$"); } Macros for code annotations Why is $l^\infty$ not separable? One of the most common gauges in QED computations are the $R_{\xi}$ gauges obtained by adding a term  \begin{equation} -\frac{(\partial_\mu A^{\mu})^2}{2\xi} \end{equation} to the Lagrangian. Different choices of $\xi$ correspond to different gauges ($\xi=0$ is Landau, $\xi=1$ is Feynman etc.) The propagator for the gauge field is different depending on the choice of gauge. The choice of Landau gauge forces $\partial_\mu A^\mu=0$, but I have never seen a similiar statement for the other gauges. I would like to know what constraint on the gauge field is produced by the other covariant gauges. For instance, what is the constraint on $A_\mu$ when $\xi=1,2,3,...$ etc. Is it still $\partial_\mu A^\mu=0$ or something different (it seems like it should be different)? "Compared with" vs "Compared to"—which is used when? Is only one of them correct? Are they used in different situations? Or are they interchangeable? Can I use my device on a different carrier? Sometimes it's desirable to use a device on a carrier that does not officially sell it. Often this is due to regional differences and travel (for example, using a US phone in Europe) but also because some carriers simply do not offer phones that other carriers do.  How can I determine if it's possible to use my phone on a different carrier, and which carriers it is compatible with?    This community wiki is intended to be a canonical answer to a common question. If you feel that improvements could be made then please edit the post(s). I noticed that when I had a helium filled, latex balloon inside of my car, it moved forward in the cabin as I accelerated forward. The faster I accelerated forward, the faster the balloon went from the back of the car to the front of the car. The balloon didn't have a string.  This became a game with my 4 year old as we drove home. We figured out where the balloon would go based on how fast I accelerated, turned corners etc.  I expected that it would act a lot like the water in a cup does, but it was the total opposite it seemed.  What forces caused this behavior?  I assumed it has something to do with the fluid dynamics in the closed cabin, but I can't figure it out. What does the "Current event" post notice mean? The recently introduced &quot;Current event&quot;  feels incomplete:  At the very least, it needs a period at the end to complete the sentence. Aside from that, what is a future visitor of a question supposed to take away from this notice? The &quot;citation needed&quot; text explains what expectations are placed on the question bearing the notice and invites action. Is the &quot;current event&quot; notice purely informational? What's the desired effect of adding it to a question? The current on-question notice is:  This post relates to a rapidly changing event.  In addition to answering those questions, I'm hoping we can work out a proposal for a wording change to make it more clear. I can't come up with anything to start with, since I don't quite get what the notice is supposed to achieve in the first place. Minecraft pocket edition restoring skin problem I updated Minecraft PE so I can have custom skins. I clicked on 'restore skins' without selecting any particular skin, It is now stuck with a  message saying 'we're restoring your skins!' but it has been like that for 20 minutes. Is there a reason why it is like this? Can I concatenate multiple MySQL rows into one field? Using MySQL, I can do something like:  SELECT hobbies FROM peoples_hobbies WHERE person_id = 5;   My Output:  shopping fishing coding   but instead I just want 1 row, 1 col:  Expected Output:  shopping, fishing, coding   The reason is that I'm selecting multiple values from multiple tables, and after all the joins I've got a lot more rows than I'd like.  I've looked for a function on  and it doesn't look like the CONCAT or CONCAT_WS functions accept result sets.  So does anyone here know how to do this? Copy every 512 bytes and skip next 8 bytes from Input file to a Output file I have an input file which is always a multiple of 520 bytes . i,e Input file 1- 1040 bytes Input file 2- 5200 bytes   I need to copy every 512 bytes from input file and skip the next 8 bytes from input files to output file i.e Output file data = Copy first 512 bytes of input file - Skip 8 bytes - Copy second 512 bytes of input file- Skip 8 bytes --.. Therefore, my output file should always be multiple of 512 bytes Input file 1- 1040 bytes        Output file 1 - 1024 bytes Input file 2- 5200 bytes        Output file 2 - 5120 bytes  I need to do this in shell script, any help here please. I have a simple one line command which works perfectly in terminal, but does not work in the "Startup Applications" app thing.  The line of code is : xmodmap /home/seph/Code/Ubuntu\ Scripts/Xmodmap  It's not that much of a hassle to copy it from "Startup Applications" and paste it into terminal, but I don't really get why it isn't working.  I followed someone else's instructions to do it in the first place, so maybe I did something wrong?  In any case, wouldn't it be the obvious and logical assumption that it just types whatever you put in it into Terminal? What is the purpose of using a FIFO vs a temporary file or a pipe? From APUE     FIFOs can be used to duplicate an output stream in a series of shell   commands. This prevents writing the data to an intermediate disk   ﬁle (similar to using pipes to avoid intermediate  disk  ﬁles).       But  whereas  pipes  can  be  used  only  for  linear  connections   between processes, a FIFO has a name, so it can be used for   nonlinear connections.      Consider  a  procedure that  needs  to  process  a  ﬁltered  input    stream  twice.   mkfifo fifo1 prog3 &lt; fifo1 &amp; prog1 &lt; infile | tee fifo1 | prog2       We create the FIFO and then start prog3 in the background, reading   from the FIFO. We then  start prog1 and  use tee to  send  its  input    to  both  the  FIFO  and prog2.    How does a FIFO "duplicate an output stream in a series of shell commands"? Isn't this done by tee instead of a FIFO? In the example, mkfifo fifo1 creates a file in the current directory, and fifo1 seems replaceable with a regular file . So what is the point of a FIFO "prevent writing the data to an intermediate disk file"? What do "linear connections" and "nonlinear connections" between processes mean? What does it mean that a FIFO can be used for nonlinear connections, while a pipe can be only used for linear connections between processes?   Thanks. Is it possible to legally visit uninhabited islands in the Pacific for a couple of days/weeks like Robinson Crusoe I have a vector file containing thousands of points. Where points are within x distance from each other, I wish to delete one of the points and keep the other (either by snapping to one point, or simply erasing one of the two points)  However, in Whitebox the vector cleaning tool only works with polygons and lines.  Is there some other way I can do this with my shapefiles? Where can I find Obsidian in the Pocket Edition? I have looked everywhere for lava or obsidian in 0.7.1. I've looked all the way from top to bottom and all around, in about a 100 block diameter, but I can't find any. Where can I get some? How to calculate $\lim \limits_{n \to \infty}(1 +\frac{a}{n})^n$? Where can I leave luggage in Frankfurt, either airport or train station? I need to find a place to leave my luggage in lockers for 2 days in Frankfurt, either the airport (Terminal 1) or at the train station. I have to go by train to Stuttgart for 2 days without luggage. The luggage is 5 bags, 28 inches. Password protecting a page I'm trying to password protect a page but it doesn't seem to be working. I've set the password for the page but when you navigate to it it just loads up like normal and doesn't ask for any passwords.  This is the loop I have on my page:  &lt;?php /**  * @package WordPress  * @subpackage Default_Theme  * Template Name: Page  */  get_header(); ?&gt;  &lt;?php global $post; if ( post_password_required( $post ) ) { ?&gt;  &lt;?php $fields = get_acf(); ?&gt;  &lt;script type="text/javascript"&gt;  (function() {   window.onload = function() {   ...  }} )  &lt;/script&gt;  &lt;div id="map"&gt;&lt;/div&gt;  &lt;?php } else { ?&gt;     Not passworded        &lt;?php if (have_posts()) : ?&gt;         &lt;?php while (have_posts()) : the_post(); ?&gt;          &lt;?php endwhile; ?&gt;     &lt;?php endif; ?&gt;         &lt;?      } // Page isn't password-protected     ?&gt; &lt;?php get_footer(); ?&gt;   I want to password protect everything within the page.  UPDATE:  I have custom content on the page so if possible I need to be able to wrap some code around it all.  Update: Debugging using Nvidia Nsight 2.2 in Visual Studio 2010