How to vertically center a floating element
How can I vertically align elements in a div?
Why do networks need a common ground cable? I was working on a tower and painted my own texture for it. I saved halfway though and took a break. When I returned to my little project, I could paint on the image and it shows up in the material view but not the render. I did everything in my power but still couldn't understand why?  I have used:   Nodes, including mapping and insert UV coordinates. Unwrap UVs Used lights Deleted and replace nodes Deleted and replace Mat Removed image and replace it Reload image Painted on mesh   Even though use blender, I am not a programmer. So I find it really helpful if someone could give me an answer. If user input is inserted without modification into an SQL query, then the application becomes vulnerable to , like in the following example:  $unsafe_variable = $_POST['user_input'];   mysql_query("INSERT INTO `table` (`column`) VALUES ('$unsafe_variable')");   That's because the user can input something like value'); DROP TABLE table;--, and the query becomes:  INSERT INTO `table` (`column`) VALUES('value'); DROP TABLE table;--')   What can be done to prevent this from happening? How can I go about determining the number of unique simple paths within an undirected graph? Either for a certain length, or a range of acceptable lengths.  Recall that a simple path is a path with no cycles, so I'm talking about counting the number of paths with no cycle. Commandline shortcut for current directory similar to ~ for home directory? When i use the cp or move command in a terminal window, i'm currently with bash in a certain folder like this.  NES@server:~/Desktop/dir1$   And now i wanna copy a file from here ~/anotherdir/dir2 into the current chosen folder in bash (dir1) i would use the command  cp ~/anotherdir/dir2/file ~/Desktop/dir1   does a shortcut string exist to refer to the current chosen directory? So that in this example i don't have to provide the full path to the target dir, but the command knows it should use the current chosen directory in bash? i.e. as ~ stands for the home directory? If the Universe is expanding, how is that galaxies run into each other? As the title says. If everything is moving outward, thrown by the Big Bang, how could two Galaxies end up with velocity vectors that run them into each other? CSS Pseudo-classes with inline styles What is a good way of parsing command line arguments in Java? How do I remove a directory and all its contents? In bash all I know is that   rmdir directoryname   will remove the directory but only if it's empty. Is there a way to force remove subdirectories? How do I control how Emacs makes backup files? Emacs puts backup files named foo~ everywhere and I don't like having to remember to delete them.  Also, if I edit a file that has a hard link somewhere else in the file system, the hard link points to the backup when I'm done editing, and that's confusing and awful.  How can I either eliminate these backup files, or have them go somewhere other than the same directory? I'm glad the outside overlay scrollbars are finally gone.  But the scrollbar is still a razor thin line that becomes a less razor thin scrollbar, but still thin scrollbar, when the mouse hovers.  How can I get a normal scrollbar? I.e., like in other OSes, like in Firefox, a scrollbar that doesn't change depending on what the mouse points to, and with a nice width.  I already tried  gsettings set com.canonical.desktop.interface scrollbar-mode normal   but no luck. How do I autohide the top panel in Unity? When windows are not maximized, the top panel is basically wasted space for me in Unity.  Is there a way to make it autohide? i.e. make it appear on mouse over. Experimental data for asymmetric Newton cradle Using a "successive impact model" (as if each ball were seperated from the other ones), I produced the following animations:    You can see any combination of balls with masses of 1 or 2 (left) or 1 and 4 (right).  Unfortunately, I do not have any Newton cradle to make some experiments, and I'd like to compare my results with observations. I contacted the author of , which is the most instructive one I found about asymmetric Newton cradle. In particular, he writes that the "OoO" configuration behaves as the "ooo" one, which is not what I simulate. But the author is not sure whether who is wrong because he did the experiments a long time ago.  I am especially interested in asymmetric Newton cradle with simultaneous impacts: left and right balls collinding at the same time.   Please let me know if you have any idea on where to find such experimental data.  Edit Just of few general remarks to avoid extending the comments.    Energy and momentum are conserved. However, they are sufficient to ensure uniqueness of the post-impact velocities only when there are 2 balls. The successive impact model precisely consists in propagating the impact ball after ball, and therefore leads to a unique solution (which conserves momentum and energy globally). From the waves point of view, changing the mass of a ball can be done by increasing the diameter, or the density (or a combination of both). This simple model cannot account for such subtleties of course, but maybe it does not matter when the balls are "small enough". Even if I think it's quite basic, following WetSavannaAnimalakaRodVance's comment, I am ready to hand out my Mathematica code to anybody who wants it. I'll check for good ways to share it. I need to upload my signature in a PDF document, but I do not know how to edit the background of this image.   I wish to remove the bluish-tint background, and make it pure white.   Can anyone help me with this, please? A tool to measure signal strength of wireless I want to know if there exists any command line option or GUI tool (Ubuntu 11.10) so that I can measure the strength of wireless signal at a given location. I have a house where the wireless is not easily accessible at all corners I want to know at which corners or rooms the signal is weak. Activity restart on rotation Android Disabling middle mouse button I have a 32GB iPhone 4 version 4.0.1. I have many photos on my phone, but I have deleted an important photo from my iPhone. How can I get this photo back from my iPhone? My customers are eager to show news categorized in tabs.  I recently developed it for them.  In my experience in web designing, display:none is used widely in implementing tabs. I also know that it is not good for SEO.  Is there any way to have tabs but without hurting SEO factors? How could I place objects (buildings) on a flat surface in the BGE? I'm working on an  in BGE, and I am not sure how I could make it so you can place buildings on flat surfaces (or unless there is an easier way). I would love to know how to place buildings when you click a certain button to place it.  I don't really need anything fancy like price and stuff like that yet. I really have no idea if  is required to do this.