One of my answers was downvoted three times and no one has left a comment, I have no idea why the answer sucks. I would like to know so that I can change it and avoid doing it in the future.  When someone downvotes an answer or question without leaving a comment as to why they think it needs be downvoted, can they lose a point? If they leave a comment then give them back their point.
Note: If you're looking for a simple explanation as to why comments aren't required on downvotes, see .   I used to get "upset" (though that is too strong a term) when I got downvoted without comment. If my answer isn't good enough then I'd like to know why. Not only does it improve the answer for the OP but it improves my knowledge too.  Where the down-vote has been explained I've found it useful &amp; it has improved my answer, or forced me to delete the answer if it was totally wrong.  So is there any way we can encourage people to leave a comment? Perhaps they don't lose rep if they explain their down-vote?  I must admit though that I haven't always explained my down-vote either so you could call me a hypocrite. I've also grown a thicker skin over the months of using SO (it seems to have come with the higher rep score ;-)), so I'm less bothered about this now.
How do I get an iball 3.5G modem working on Ubuntu? I purchased iball 3.5G  connect wireless modem 1 month before. I am trying to connect it with my laptop which is having ubuntu Operating System. After plug-in it to the ubuntu system it is not connecting with net.   This modem is plug and play but after plugging it nothing is displaying to the system.  I am expecting step-by-step method to connect this modem with my ubuntu 12.04 LTS sysetm from your expert's advice. The  is minimal and clean on a fresh installation of Windows. Install a bunch of applications and soon the context menu is loaded with all kinds of opening options from various applications.  How do I remove items from the right click (context) menu?  I find that there are different types of right click menu items:   Global items that appear in all context menus. Items that appear only on folders. Items that appear only on files. Items that appear only on special folders (Ex: Right clicking a folder of MP3s shows up a context menu with items like Play with Windows Media Player.) Items that appear only on certain file types (Ex: Right clicking a MP3 file shows up a context menu with items from Windows Media Player/Foobar2000/VLC/your-favorite-media-player begging to open this file.)   I want to be able to delete all these kinds items from the right click (context) menu. What measures does Cognito Forms take to ensure Privacy/ Security Level for Completed Forms/ User Data? Some forms may contain confidential information - even something basic like where a person lives.   What measures do Cognito Forms take to ensure that data stored within its site is secure? Can I run my CPU at 100% usage for a long time? I have a Dell XPS 15 9570, 32 GB ram, 2.2 ghz and 6 cores. When i use an application (The parsim command on MATLAB) ()  then my fan starts running fast , during this my PC doesn't seem to be heating but it never got this noisy in the past so it got me worried. In my task manager , the CPU usage shows 100% when this application is running.   Is it a problem for the life of laptop, if I run the PC at CPU 100% for like 4 hours in a day? Do I need to be worried about the noisy fan during the application? Forcing linebreaks in \url List the files accessed by a program I'm working in C, and I have to concatenate a few things.  Right now I have this:  message = strcat("TEXT ", var);  message2 = strcat(strcat("TEXT ", foo), strcat(" TEXT ", bar));   Now if you have experience in C I'm sure you realize that this gives you a segmentation fault when you try to run it. So how do I work around that? Thesis running problem in KILE I'm using  editor. There is no problem when I run others  .tex article in Kile. But problem is when I run a thesis article in KILE. This thesis article is running fine in      \documentclass[12pt,a4paper]{thesis}     \usepackage{amsmath}\usepackage{amssymb}     \usepackage{graphicx}   Is there anything need to add in KILE setting to run the Thesis .tex in KILE?  This is the log file:  This is pdfTeX, Version 3.1415926-1.40.10 (TeX Live 2009/Debian) (format=latex 2013.3.7)  25 AUG 2013 23:37 entering extended mode  %&amp;-line parsing enabled. **Thesis-Aug24-2013.tex (./Thesis-Aug24-2013.tex LaTeX2e &lt;2009/09/24&gt; Babel &lt;v3.8l&gt; and hyphenation patterns for english, usenglishmax, dumylang, noh yphenation, loaded.  ! LaTeX Error: File `thesis.cls' not found.  Type X to quit or &lt;RETURN&gt; to proceed, or enter new name. (Default extension: cls)  Enter file name:  ! Emergency stop. &lt;read *&gt;   l.2 \usepackage                {amsmath}\usepackage{amssymb}^^M *** (cannot \read from terminal in nonstop modes)   Here is how much of TeX's memory you used:  10 strings out of 495062  226 string characters out of 1182645  45108 words of memory out of 3000000  3285 multiletter control sequences out of 15000+50000  3640 words of font info for 14 fonts, out of 3000000 for 9000  28 hyphenation exceptions out of 8191  10i,0n,7p,80b,8s stack positions out of 5000i,500n,10000p,200000b,50000s No pages of output. It's the first time I'm using Tikz on Latex. I have to draw this block diagram (this is a low resolution snip from a paper)   In Tikz I have done this:   That is very similar but I need some adjustments, like the u_i arrow and the node sum after the H(s) block.  Is there anybody that can help me with this?  my code:      \tikzstyle{block} = [draw, fill=white, rectangle,  minimum height=2em, minimum width=3em] \tikzstyle{sum} = [draw, fill=white, circle, radius=1mm, node distance=1.5cm] \tikzstyle{input} = [coordinate] \tikzstyle{output} = [coordinate] \tikzstyle{pinstyle} = [pin edge={to-,thin,black}]  \begin{tikzpicture}[auto, node distance=2cm,&gt;=latex'] \node [input, name=input] {}; \node [input, above of=input](input1) {}; \node [sum, right of=input] (sum) {}; \node [block, right of=sum] (controller) {$K(s)$}; \node [sum, right of=controller] (sum1) {}; \node [block, right of=sum1] (filterinv) {$H^{-1}(s)$}; \node [block, right of=filterinv] (system) {$G(s)$}; \node [output, right of=system] (output) {}; \node [output, above of=output] (output1) {}; \node [block, below of=filterinv] (filter) {$H(s)$}; \node [block, above of=controller] (delay) {$D(s)$}; \node [sum, below of=sum1] (sum2) {};  \draw [-&gt;] (filterinv) -- node[name=u] {$u_{i}$} (system); \draw [draw,-&gt;] (input) -- node {$s_{i-1}$} (sum); \draw [-&gt;] (sum) -- node {$e_{i}$} (controller); \draw [-&gt;] (system) -- node [name=q] {$q_{i}$}(output); \draw [-&gt;] (q) |- (filter); \draw [-&gt;] (filter) -- node {} (sum2); \draw [-&gt;] (controller) -- node {} (sum1); \draw [-&gt;] (sum1) -- node[name=xi] {$\xi_{i}$} (filterinv); \node [input, below of=sum1](input2) {}; \draw [draw,-&gt;] (input2) -- node {$r_{i}$} (sum2); \draw [-&gt;] (sum2) -| node[pos=0.99] {$-$}      node [near end] {$\tilde{s}_i$} (sum); \draw [-&gt;] (delay) -| node[] {}      node [near end] {} (sum1); \draw [draw,-&gt;] (input1) -- node[pos=0.15] {$u_{i-1}$} (delay); \draw [-&gt;] (u) |- node[pos=0.99] {$u_i$}      node [near end] {} (output1);  \end{tikzpicture} How do you correctly use a meat thermometer? I have a new HP Z800 Workstation, running Windows 7 Enterprise 64 bit. Z800 Specs are .  The machine has 4GB of RAM -- windows reported 1.99GB available, 2GB was "hardware reserved".  I added another 2 GB and windows reports that there is 6GB of physical RAM, but now 4GB is "hardware reserved".  The BIOS sees the full RAM amount as well.  The video card is an nVidia Quadro FX 580, so it shouldn't be using any shared memory at all.    Why is all my extra RAM marked as "hardware reserved" in Windows 7? Overstaying on a US Visa Waiver Program A friend of mine came from Australia on the WVP and stayed 92 days. I made a mistake booking Her flight scheduling a Saturday arrival/departure at DFW. This amounted to a 92 day stay and with no funds to rebook a low cost flight through Qantas it was necessary to leave on the scheduled flight.   Question # 1) Was a automatic I-94W submitted by the airlines? She had no customs forms to fill out upon departure.   Question #2) How does this effect another WVP being issued if applied for? How do you check the windows version in Win32 at runtime? How do you check the windows version in Win32 at runtime? I would like to get the path to the execution directory of a Windows Forms application. (That is, the directory in which the executable is located.)  Does anyone know of a built-in method in .NET to do this? How can I play the same world between PS4 and Mobile? How many keys does the Playfair Cipher have? Movie with a town where it is always night and the protagonist has amnesia I can't remember the name of this fairly recent movie. The protagonist wakes up in a bath tub without memories. He breaks up with his wife, gets in touch with a "doctor" who claims to be able to help him, and is accused of serial killing prostitutes. The sun never seems to go up. The main plot device:       The town is in perpetual darkness. It is the experiment of a hive-mind race, that tries to understand why humans are individual. To achieve this, they move humans' memories around. They can shape the world with thought, and when the protagonist learns this power, he challenges them, destroying them. It is revealed that the Earth is long since gone, and he lives on in this false world.   I've looked for titles like City of Night and City of Darkness, but can't find it. I started reading "The Mathematics of nonlinear Programming - AL peressini" recently.  Theorem : Suppose that $f(x) , f'(x) ,f''(x)$ exist on the closed interval $[a,b]$. If $x^* ,x $ are two different points of $[a,b]$ , then there exists a point $z$ strictly between $x^*$ and $x$ such that   $$f(x)=f(x^*)+f'(x^*)(x-x^*)+\frac{f''(z)}{2}(x-x^*)^2$$  I tried to prove this theorem using The Fundamental theorem of calculus. But I can not stop it at the second derivative . Do I have to use mean value theorem ? or is there a simple proof for this ? Digits of $\pi$ forming primes? Let $f(n)$ be the first $n$ digits of $\pi$ . How many times is $f(n)$ prime on the interval $[1, k]$ ? Are there infinitely many prime $f(n)$'s on $[1, \infty)$?  I know this is probably be a very hard question and most likely an open problem, but I am just curious. I wish to have long and short forms of command line options invoked using my shell script.  I know that getopts can be used, but like in Perl, I have not been able to do the same with shell.  Any ideas on how this can be done, so that I can use options like:  ./shell.sh --copyfile abc.pl /tmp/ ./shell.sh -c abc.pl /tmp/   In the above, both the commands mean the same thing to my shell, but using getopts, I have not been able to implement these?