Is there any difference at all between these two sentences? Why would a native speaker choose one over the other?  a) She had suffered from asthma when she was very young.  b) She suffered from asthma when she was very young.  Thank you.  Nawee
I noticed that my American friends tend to use the past perfect form when they use the verb mention in its past form, almost despite of the context of the sentence. I hear them say  "you had mentioned" a lot more often even in situations where the use of simple past would have been perfectly fine. Have you noticed it too and is it one of those unwritten rules, or is there a more formal explanation to it?  It seems like there was more verbs like that, but I am having a hard time remembering it now. If I do, I will edit the post and likely change the title to accommodate other verbs.
PHP calculate age Any real-time antivirus for Ubuntu? Make "axis cs" the default coordinate system in a PGFPlots plot I would like to know if there is a way to specify axis cs to be the default coordinate system inside a plot in PGFPlots, so I don't have to type axis cs: in front of every coordinate pair. Here's a MWE that shows what I mean (the actual plot is irrelevant).  \documentclass{article}  \usepackage{pgfplots}  \begin{document}  \begin{tikzpicture}  \begin{axis}[               xmin=0,               xmax=80,               ymin=0,               ymax=80,               grid=major,              ]   \fill [green, opacity=0.5] (axis cs:14,14) -- (axis cs:80,47) -- (axis cs:80,80) -- (axis cs:47,80) -- cycle;   \fill [red, opacity=0.5] (0,0) -- (axis cs:80,0) -- (axis cs:80,47) -- (axis cs:14,14) -- (axis cs:47,80) -- (axis cs:0,80) -- cycle;   \draw [thick] (axis cs:47,80) -- (axis cs:14,14) -- (axis cs:80,47);  \end{axis} \end{tikzpicture}  \end{document} Why does main method in Java always need arguments? Error when clipping raster in QGIS: "'ascii' codec can't encode character"? I have done it many times (clipping a raster with a polygon layer or by extension) but today I got an error for the first time and I don't know how to solve it. I am always using the same type of raster layers. When running the clipping tool I got the following message:  gdal_translate -of GTiff -ot Byte -projwin 410282.185971 4694950.41162 410783.882475 4694524.96815 -co COMPRESS=DEFLATE -co PREDICTOR=1 -co ZLEVEL=6 -co TFW=YES "C:/Users/FERRAN ALA/Desktop/Justificació Fontanals/QGIS/Topo 1_5000/bt5mv20sd0f283077st1r031.sid" "C:/Users/FERRAN ALA/Desktop/Justificació Fontanals/QGIS/background/image.tif"   GDAL command output:     'ascii' codec can't encode character u'\xf3' in position 201: ordinal not in range(128) See log for more details   Does anybody know what that is? Shannon confusion and diffusion concept I read the document(not the whole document) from Shannon where he speaks about the concepts of confusion and diffusion. I read in many places(not in the document but around the internet) that confusion is enforced using substitution. Diffusion is enforced using permutation/transposition. Ciphers must use both of them because either confusion or diffusion alone are not enough. I read that a substitution cipher can apply by itself confusion(only). Permutation/Transposition applies by itself diffusion(only). It's precisely the last case that bothers me: Can a permutation/transposition cipher by itself apply diffusion?  Shannon explains diffusion as a property that spreads statistic properties of text all over the text preventing statistic analysis. It's frequently translated to: an alteration to a plaintext symbol affects many cipher text symbols. Assuming permutation of bits or characters, how can diffusion be achieved by simple permutation? I mean, if you permute bits, there will be no other bits affected. But if you consider a symbol a character and you permute bits, a change in a character will affect many other characters. It's a question of what is a symbol.  I also read versions of this diffusion concept where the point was just changing bits order just to avoid pattern analysis of the text. But, where is the avalanche effect in simple permutation?  So, what is the correct definition and the implications of diffusion?  I hope you understand what is troubling me.  Thank you once more Integral $\int\frac{2x^2}{2x\cos(2x)+(x^2-1)\sin(2x)} \mathrm d x$ Integrate  $\displaystyle\int\dfrac{2x^2}{2x\cos(2x)+(x^2-1)\sin(2x)} \mathrm d x$   I tried dividing by $\cos^2(x)$ and then substituting $\tan(x)=t$. Hello,  I'm getting this error every time when I boot my computer. My Ubuntu installation is fresh and I was got a few error on last step while install Ubuntu (because i have problem with my CDROM driver). Anyway, installation is continued .   For example when i tried to open ADDITIONAL DRIVER and LANGUAGE SUPPORT (on System Settings) nothing happened, it's not opening.  When i try this in terminal gnome-language-selector i'm getting this error  Traceback (most recent call last):   File "/usr/bin/gnome-language-selector", line 8, in &lt;module&gt;     from LanguageSelector.gtk.GtkLanguageSelector import GtkLanguageSelector   File "/usr/lib/python2.7/dist-packages/LanguageSelector/gtk/GtkLanguageSelector.py", line 34, in &lt;module&gt;     from aptdaemon.gtk3widgets import AptProgressDialog   File "/usr/lib/python2.7/dist-packages/aptdaemon/gtk3widgets.py", line 61, in &lt;module&gt;     class AptStatusIcon(Gtk.Image):   File "/usr/lib/python2.7/dist-packages/aptdaemon/gtk3widgets.py", line 66, in AptStatusIcon     def __init__(self, transaction=None, size=Gtk.IconSize.DIALOG): AttributeError: type object 'GtkIconSize' has no attribute 'DIALOG'   Also getting this error for jockey-gtk  Traceback (most recent call last):   File "/usr/bin/jockey-gtk", line 418, in &lt;module&gt;     sys.exit(u.run())   File "/usr/lib/python2.7/dist-packages/jockey/ui.py", line 461, in run     self.ui_show_main()   File "/usr/bin/jockey-gtk", line 81, in ui_show_main     col_icon.set_sizing(Gtk.TreeViewColumnSizing.AUTOSIZE) AttributeError: type object 'GtkTreeViewColumnSizing' has no attribute 'AUTOSIZE'   I'm worrying about are there any lack . I don't know what's wrong with my installation.  Are there any way, check my installation (packages, files etc..) . Copy-paste from question to snippet When I'm editing a stack snippet, I often want to copy code from the original question into the snippet. But while the snippet editor is on display, there's no way to access the question, other than opening another tab/window. What I often do instead is copy all the code in the question to the clipboard, open the snippet editor, then paste it all in and revise it to what I want. But when the original code is poorly designed, that ends up being more work than just copying the bits and pieces that I want.  There could be a "View Question" button that pops up the question over the snippet editor and allows copying. Or maybe the Snippet Editor could be draggable and resizable, so you can reveal the question and copy from it; but this would require that it not be purely modal. Torque direction meaning I apologize if this question is dumb, but I've looked all over for a straightforward answer, and either I can't find one or either the terms are too complex for me to understand. I have only a rudimentary knowledge of Mechanics, but I do understand basic Linear Algebra. So torque, mathematically, is the cross product of the radial distance vector and a force vector. This cross-product gives another vector that is orthogonal to both vectors and it points either outside or towards the &quot;page&quot; (in the context of a two-dimensional diagram). Assuming this is correct, I do not understand what it pointing in or out means. Does it even have a physical, intuitive meaning? The best answer I've been able to come up with is that it's just a mathematical convention with no actual physical meaning, meant to provide a framework within which operations between torque vectors, such as addition and subtraction, make sense. Am I correct or way off the mark here? I was asked today in class why you divide the sum of square error by $n-1$ instead of with $n$, when calculating the standard deviation.  I said I am not going to answer it in class (since I didn't wanna go into unbiased estimators), but later I wondered - is there an intuitive explanation for this?! What is the correct way to edit a crontab file? I just would like to know if a question or an answer saved draft is visible to someone else, apart from the OP.  Will a copy of a saved draft remain visible even after it has been deleted? Who has access to it? Can I recover app data after the phone has been Factory Reset? 'apt-get' does not work with Proxy For the command   sudo apt-get update   I get following error:  W: Failed to fetch http://ch.archive.ubuntu.com/ubuntu/dists/maverick-updates/multiverse/binary-i386/Packages.gz   407  Proxy Authentication Required (The ISA Server requires authorization to fulfill the request. Access to the Web Proxy filter is denied. )   I am running Ubuntu 10.10 installed on Windows XP using VirtualBox. For Internet connections I am using proxy server with an authentication. I tried to use gnome-network-proxy tool to set proxy settings system-wide.   After that /etc/environment has been updated by http_proxy variable with the format http://my_proxy:port/, there were no authentication data.  I checked this with Firefox. Browser asked my for login and password and everything was working fine. It was unfortunately not the case for apt-get. I have also tried to do as described . Unfortunately it does not work.  May it be somehow related to the fact that a proxy is in a Windows domain, any ideas?  My proxy name is http-proxy. Is '-' a special character here? I came across a phrase for a type of question which is designed to discover someone's religious background, particularly in the context of sectarianism and divided societies but can't for the life of me remember it.   For example, if you are in Scotland and I ask you what football team you support, that may reveal your religion. Or in N.Ireland, if I ask what school you attend, likewise that may do the same.  It's like a 'veiled question' only that's not the term I'm looking for. Any help appreciated.  I've a feeling that the second part of the phrase is (question) as in, a INSERT TERM question, but not 100% sure. Computer wont boot to windows I recently installed a Linux operating  system (backtrack 5 r3) I couldn't connect to the internet with it so I removed the partition manually. After that, whenever I turn on my computer it goes to a command line that says "error no File-system found" "Grub Rescue/"  I have tried f12 and booted into all the options. I also put Ubuntu 12.04 on my flash drive and tried installing it on the computer, the installation failed saying "No Available Space"  My hard-drive is 500g with about 250 left. I put the hard drive in another computer (as a secondary just to see the files. It had 2 partitions a main and one with 1 gig. I formatted it with no difference.  My Problem: I can't boot into Windows Do Squibs have to be pure-blood? If a Muggle was born of a wizard/witch and a Muggle, is that person a Squib, or is that reserved to people born from pure-blood families?    (Related: ) How to use x coordinate of a point and y coordinate of other point? Possible Duplicate:             How to use x coordinate of a point and y coordinate of other point? I need similar to  \coordinate (A) at (2,1); \coordinate (B) at (3,0); \coordinate (C) at (4,3); \coordinate (D) at (5,-1);  \draw (xA,yB) -- (xC,yD); React on global hotkey in a Java program on Windows/Linux/Mac? A Java6 application sits in the system tray. It needs to be activated using a hotkey (e.g. Super-G or Ctrl-Shift-L etc) and do something (e.g. showing an input box).  How do I do that on:   Windows (XP or Vista) OS/X Linux (Gnome or KDE)