Title/Request Elaborated:   Down voting an answer is a privilege given to users who have at least 125 reputation points. I am requesting for a feature to prevent users from down voting (other) answers to the question, as soon as the user gives his/her own answer to the question. As a follow up, a user who has down voted an answer to a question, the user shall then be labelled as a referee, and his/her privilege to give an answer shall get revoked. Optionally, the user may be given the option to sacrifice his/her down votes to answers in that question, for the sake of giving his/her own answer to the question.   Motivation:  Users are generally able to be objective while giving up and down votes, provided they have given an answer to a question. As soon as they give an answer, however, they more or less lose their objectiveness. While a user would definitely not vote an answer other than his/hers up for having lost objectiveness; this is not the case for voting down...  A user may vote an answer down, simply because it is not theirs. <<< this is the tl; dr  I think we would all agree that in any sports, it wouldn't be appropriate to let a player be a referee. We don't allow this for up-votes, by disallowing casting up-votes for our own answers; and this suggestion/request asks one for the down-vote counterpart.

Possible Duplicates:        As Dan Dyer mentioned in his comment on , there is a conflict of interest when you have posted your own answer and are allowed to downvote other answers.  Despite the vote editing window being drastically reduced, the fundamental problem remains: I can downvote the other answers permanently and still benefit - my answer gets upvoted ONCE and wham, I have just made up the rep loss for my 10 other downvotes. The vote editing window fixes part of the problem, but there is a more complete fix that has the extra benefit of not preventing legitimate vote changes: to disallow downvotes on competing answers when you have posted one yourself.  The temptation to wrongfully downvote competing answers is huge. The rep loss is tiny in comparison. It has to be in order for people to continue to legitimately downvote.  Details:   If I have previously voted and then post my own answers, delete my downvotes. Continue to allow me to remove the upvotes - I think this is fully legitimate. If I delete my answer it's probably best to continue to deny downvotes (perhaps even including the question), but I don't have a strong opinion either way.


i have simple page which takes comment from user and add it to database. it even works good whenever there is plane comment of user. but when users comment contains symbol like ' this it shows error. plz help  code is:---  $title=$_POST['title'];  $message=$_POST['message'];  $message=htmlspecialchars($message); mysqli_query($conn,"insert into  diary(no,datetime,title,mydiary)values(null,now(),'$title','$message')");   and error when comment contains symbol '   Error description: You have an error in your SQL syntax; check the manual  that corresponds to your MySQL server version for the right syntax to use   near 'th')' at line 1

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?


I am working on Big Data Analytics, I would like to know how well k means algorithm can be used for clustering Big Data?

K-means is a widely used method in cluster analysis. In my understanding, this method does NOT require ANY assumptions, i.e., give me a dataset and a pre-specified number of clusters, k, and I just apply this algorithm which minimizes the sum of squared errors (SSE), the within cluster squared error.  So k-means is essentially an optimization problem.  I read some material about the drawbacks of k-means.  Most of them say that:   k-means assumes the variance of the distribution of each attribute (variable) is spherical;  all variables have the same variance; the prior probability for all k clusters is the same, i.e., each cluster has roughly equal number of observations;   If any one of these 3 assumptions are violated, then k-means will fail.  I could not understand the logic behind this statement. I think the k-means method makes essentially no assumptions, it just minimizes the SSE, so I cannot see the link between minimizing the SSE and those 3 "assumptions".


The hot questions widget seems unable to load questions. This has been going on for the last one month, I have tried clearing app data, removing and reinstalling the app, removing and recreating the widget but all to no avail.   App Version: 1.0.92 Device Manufacturer: OnePlus Device Model: ONE A2003 OS Version: 6.0.1 (31)

App Version: 1.0.89 Device Manufacturer: LGE Device Model: Nexus 5X OS Version: 7.1.2 (3769476)   I have reinstalled the app, logged in again but the problem remains.


I am attempting to make a macro shortcut for the \mathrm command from amsmath.  My idea is that in lieu of writing, for example, \mathrm{R} to get the Roman R in math mode, I'd like to enter \RR instead.  Likewise, suppose I wanted Roman P, I'd like instead to enter \PP.  The following MWE gets me the Roman R symbol, but I'd like this to be maximally flexible for any letter without having to define 52 separate \aa, \bb, \cc  commands.  \documentclass{book} \usepackage{amsmath}  \newcommand{\RR}{\mathrm{R}}  \begin{document}  $ \RR$  \end{document}

In order to separate the content structure from the style, I decided to implement commands for denoting random variables:  \newcommand{\myrv}[1]{\mathbf{#1}} \newcommand{\rvA}{\myrv{A}} \newcommand{\rvB}{\myrv{B}} \newcommand{\rvC}{\myrv{C}} ...   This way, if I ever decide to change the style of random variables from \mathbf to say \mathbb, all I need to do is to change the definition of \myrv. Is a way to generate the commands \rvA, \rvB, \rvC, ... automatically?


The report said that years ago city planners had planned to build a facility that turns salt water into fresh water, but financial woes made that impossible.   In this sentence should turned be used instead of turns?

I know the past tense carries the past tense in every dependent clause, but referring specifically to places or to things that are eternal, like the Earth, seems a bit weird and therefore we sometimes (I believe incorrectly) say     He didn't know that New Jersey was actually on the East Coast.   Because it still is. Or     He thought the Earth was round.   So is it square now?  Logically speaking, would you consider the use of past tense here a bit confusing in a day-to-day speech in these examples? Would you instinctively opt for using the present tense?


The question is to find $\lim\limits_{n\to\infty} \cos \frac{x}{2} \cdot \cos \frac{x}{2^2} \cdot \cos \frac{x}{2^3}\cdot\cdot\cdot \cos \frac{x}{2^n}$.  I first thought of several facts: 1). $-1 \leq \cos(a) \leq 1$ (From this I know the sequence is also bounded by -1 and 1) 2). $\cos(0) = 1$ (This is what the items in the sequence tend to, as n becomes bigger) 3). When $x=0$, the limit is 1.    Then I failed to think more and the above do not get me anywhere close to finding the limit...    Can anybody teach me how to find the limit of this sequence? Thanks a lot.

This limit seemed quite unusual to me as there aren't any intermediate forms or series expansions which are generally used in limits. Stuck on this for a while now .Here's how it goes :    $$ \lim \limits_{n \to \infty} \left[\cos\left(x \over 2\right)\cos\left(x \over 4\right)       \cos\left(x \over 8\right)\ \cdots\ \cos\left(x \over 2^{n}\right)\right] $$


I'm using a grammar checking service. It tells me these kind of projects is wrong and should be changed to these kinds of projects. I'm not sure about the correctness of this suggestion, so I googled it on the Google Books website. You can take a look at the result  and .  Both searches returned many results, and these are from books, which I assumed to be correct. Could anyone help to explain? Thanks in advance.

A. These kinds of problem are to be avoided. B. These kind of problems are to be avoided.  Are both A and B grammatical? If not, why not? If so, after having noticed the parallelism between A and C, and between B and D, could we say that C and D are "standard" English, too?  C. These kinds of problem are ones to avoid. D. These kind of problems are ones to avoid.


I am working on the following problem.  Let $g : V\to V$ be linear and injective, where $V$ is a vector space over the field K. Prove that, if $V$ is finite-dimensional, then $g$ is surjective.  In an attempt to solve the problem, I have done the following.  I first chose a basis $\{e_1, \ldots, e_n\}$ for $V$ (assuming that $\dim(V) = n$) and considered the images under g of $e_1, \ldots, e_n.$    I then attempted to prove the required statement by contradiction. I assumed that $g$ is not surjective. Then $\exists \space v_d\in V$ s.t. (such that), $\forall \space v_c \in V \space \forall \space \gamma_1, \ldots, \gamma_n \in K$, we have that $\gamma_1 g(e_1) + \ldots + \gamma_n g(e_n) \not= v_d.$ $(*)$  My next thought was that, if I could show that the vectors $g(e_1), \ldots, g(e_n)$ formed a basis of $V$, then $(*)$ would imply that no linear combination of these vectors was equal to $v_d$, contradicting the definition of a basis. Consequently, I managed to show that $g(e_1), \ldots, g(e_n)$ are linearly independent. However, I am now struggling to show that $g(e_1), \ldots, g(e_n)$ span $V$. I would appreciate any hints which could help me progress.  NB: Firstly, the question tells me not to use the Rank-Nullity Theorem. Secondly, I am aware that, since $g$ is injective, $\ker(g) = \{0\}.$

I am asked to prove this without the rank nullity theorem   My Attempt at a Proof  For the $\implies$; If $g:V \rightarrow V$  is injective then the dimension of the kernel is 0, and so as ($im$) and ($ker$) are both subspaces of $V$, $dim(im)=dim(v)$ which implies $g$ is surjective.    For the $\impliedby$ ; If $g:V \rightarrow V$  is surjective, then $dim(v)=dim(im)$ and $dim(ker)$ must be 0, so $g$ is injective.    It seems to me that i have indirectly used the  rank nullity theorem, would there be a more suitable proof that doesn't incorporate it?


After I upgraded to Windows 10, free disk space went from 100 GB to 5 GB on my 205 GB system disk over the course of about two months. I am not aware I installed any programmes that could cause such drop in free disk space.  I tried Disk Cleanup, but it did not free much disk space.  What are some tips reclaim the disk space on Windows 10?  Any help is appreciated.

I recently upgraded to Windows 10. It's been a pretty rocky road thus far. My current issue is Windows 10 keeps using up my SSD's disk space until it has none left and then complains I have no space left. I keep my data on a separate drive, and just the OS on the SSD.  Every time I look at the drive, there is less and less space. I clear a few gigabytes of stuff so it is at 4 GB free space, then it quickly starts going back to 0. It's not temp data, so how do I figure out what is using up all this space?


I am trying to solve the following limit:  \begin{equation} \lim_{x\to 0} \left(\frac{\sin x}{x}\right)^{\frac{1}{x^{2}}} \end{equation}  I tried using $ \ln $ to get a exponential expression for the equation as follows:  \begin{equation} \text{Let} \,\, y = \left(\frac{\sin x}{x}\right)^{\frac{1}{x^{2}}} \end{equation}  Apply $ \ln $ to bring down power and apply exponential:  \begin{equation} y = \exp\left(\frac{1}{x^{2}}\ln\left(\frac{\sin x}{x}\right)\right) \end{equation}  I have no idea how to solve the limit for $y$. From what I read, it can be done using l'Hopital  rule but I am unable to get an indeterminate form no matter how I try. Could somone please assist me?

Find the following limit: $$\displaystyle\lim_{x\to 0+} \left(\frac{\sin x}x\right)^{1/{x^2}}$$   Well I tried to do the $\exp\left(\frac{ \ln\frac{\sin x}{x}}{x^2}\right)$ then apply LHR but I seem to get to endless dervivations...   There's got to be a more simple approach.


I made a small kernel module called hello.ko, and inserted it via insmod command and removed it via rmmod command.   Now I want to insert this module via the modprobe command.  I copied the hello.ko file to /lib/modules/4.13.0-31-generic/ directory and the keyed in the command sudo modprobe hello.ko in the linux terminal and got the following error :  modprobe: FATAL: Module hello.ko not found in directory /lib/modules/4.13.0-31-generic   Kindly let me know where I am going wrong and how to insert a kernel module via the modprobe command.

I'm trying to get a kernel module to load at boot.  If I run insmod /path/to/module.ko, it works fine. But this has to be repeated every time I reboot.  If I run modprobe /path/to/module.ko, it can't find the module. I know modprobe uses a configuration file, but I can't get it to load the module even after adding /path/to/module.ko to /etc/modules.  What is the proper configuration?


I need an execute command that outputs as 'true' when the number of Iron Ingots on the ground is above 100. I have attempted this in the only two ways I could think of, and so far neither have been successful.  The first thing I tried was to make a comparator output from the Command Block with /execute if @e [nbt.... That only outputs a signal strength of 1, no matter how many Iron Ingots there were. The other way I tried was to use a limit, but that would only work if I needed it to put an output if it was less than 100.  [edit] OK so somebody marked this question as a duplicate of how to count items on the ground, so I have to explain why its not apparently. So the other one specifically asked about bed-wars. This one could be applied to bed wars I guess, but the other one didn't answer my question. (well somebody might have I was just too dumb to understand it.) So I redid the question into this one, which again is just for my knowledge about command blocks, so if I need something like this in the future. Sorry if my edit was a little wordy, I have never been good at English anyway.

Items on the ground clump together in stacks, so getting the number of entities doesn't give me the number of items there are. Is there a way to count the number of items instead of the number of item entities?


I used the SE Android app in the past and I normally log into Stack Exchange through Facebook. But on the app, I don't have a FB login button.  How do I login using my FB login ID like I do on the website?

I just downloaded the Stack Exchange app from Play Store and when I tried to login there was no option to login with Facebook, am I missing something? Is it connected with OpenID?


this code compiled and executed well without using const. Is there a special reason for using const in here?  0   #include <iostream> 1   using namespace std; 2 3   int sum(const int array[], const int length) { 4     long sum = 0; 5     for(int i = 0; i < length; sum += array[i++]); 6     return sum; 7   } 8 9   int main() { 10    int arr[] = {1, 2, 3, 4, 5, 6, 7}; 11    cout << "Sum: " << sum(arr, 7) << endl; 12    return 0; 13  }    code reference: MIT C++ Open Course Lecture Note 4 "Arrays and Strings" URL:

How far do you go with const?  Do you just make functions const when necessary or do you go the whole hog and use it everywhere?  For example, imagine a simple mutator that takes a single boolean parameter:  void SetValue(const bool b) { my_val_ = b; }   Is that const actually useful?  Personally I opt to use it extensively, including parameters, but in this case I wonder if it's worthwhile?  I was also surprised to learn that you can omit const from parameters in a function declaration but can include it in the function definition, e.g.:  .h file  void func(int n, long l);   .cpp file  void func(const int n, const long l)   Is there a reason for this? It seems a little unusual to me.


Problem Show that $f(t)=t^5-5t+1$ has no repeated roots. My initial idea I write $f$ in terms of linear factors $(t-\alpha_1)...(t-\alpha_5)$ where all the $\alpha_i$ make up the five roots of $f$. I’d like to show that each possibility of there even existing multiplicities in the factorization leads to a contradiction. The following statements are all that is necessary to prove the original question without loss of generality and after renumbering the $\alpha_i$. The first case would be that $f(t)=(t-\alpha_1)^2(t-\alpha_2)(t-\alpha_3)(t-\alpha_4)$. The second would be that $f(t)=(t-\alpha_1)^2(t-\alpha_2)^2(t-\alpha_3).$ The third case would be that $f(t)=(t-\alpha_1)^3(t-\alpha_2)(t-\alpha_3)$, and so on proving the rest of these possibilities until they are all exhausted out. My question Obviously, this is time consuming and there’s likely a better solution. I would like any suggestions on how to solve the problem quicker without this exhaustive method. Any thoughts would be appreciated. Remark I tagged irreducible polynomials and gcd/lcm because I am not sure if any suggestions would have to do with them, yet I still suspect that they would.

I don't know how to start the question. The title is self explanatory. How to approach and make a formal proof?


I'm finishing my degree in Art History soon and I'm realizing I am not as interested in my major than I originally thought I was. The idea of going to graduate school or working in an art history related field makes me feel really hopeless because I do not see myself working in such an industry.  I loved graphic design in high school and I've missed it all through my time at uni. I've chosen to carry on to a career in design (graphic or maybe even interior) but I do not feel like I have the time for another four-year degree. That, and I don't think I could handle another 4 years of university.  Will a diploma in graphic design suffice for a future career in the industry? What was it like entering the industry as someone with a diploma? I'm excited about beginning my new career path but also really nervous! Advice would be appreciated!

Is it required for people to go to design schools to become a Graphic Designer? I've heard many cases where they have started from scratch without previous education in design and are doing fine as freelancers/working in studios.  Would it be better to go to a design school to become a Graphic Designer? How much leverage would it give you if you went to one?


I'm writing a document (article class), and I'm including some png graphics, this is the code that includes them (it's a subimage environment):  \begin{center} \begin{figure}   \centering   \begin{subfigure}[b]{0.3\textwidth}                 \includegraphics[natwidth=512px,natheight=511px,width=4cm,height=4cm]{param.png}                 \caption{img1}                 \label{img1}         \end{subfigure}%         ~ %add desired spacing between images, e. g. ~, \quad, \qquad, \hfill etc.           %(or a blank line to force the subfigure onto a new line)         \begin{subfigure}[b]{0.3\textwidth}                 \includegraphics[natwidth=512px,natheight=511px,width=4cm,height=4cm]{crtpnt.png}                 \caption{img2}                 \label{fig:img2}         \end{subfigure}         ~ %add desired spacing between images, e. g. ~, \quad, \qquad, \hfill etc.           %(or a blank line to force the subfigure onto a new line)         \begin{subfigure}[b]{0.3\textwidth}                 \includegraphics[natwidth=512px,natheight=511px,width=4cm,height=4cm]{ferro.png}                 \caption{img3}                 \label{fig:img3}         \end{subfigure} \caption[prueba]{\label{fig:images}caption}\end{figure}\end{center}   I'm compiling through latex and then dvipdf to get a pdf. Firt of all, if I compile with pdflatex it works perfectly, but I would like to compile with an intermediate dvi file. When running Latex the dvi file is alright, although images don't show up. If I run then the dvipdf, it cuts the document up to the page in which the previous snippet is, not showing the images, or anything else beyond them.  I have previous images in eps format which are perfectly included. Is the way I'm including png graphics right? Am I doing anything wrong?

There several types of graphics files. In no particular order .jpeg .eps .pdf .png .tif .jif (and no doubt others). Some work with latex, dvips and some work with pdflatex. How am I supposed to know which?  Just to confuse matters, metapost produces .eps but I can use these with pdflatex as long as I put in a four line incantation.  Can anyone explain this?


I have had a Gmail account for years. Now I have bought a domain which I set up with Google Apps and want to use a couple of email addresses for one Gmail account.  I have email addresses like:  contact@mydomain.com //setup by Google Apps mymail@gmail.com support@mydomain.com   I want to use one email account to send/receive those multiple emails. When a email comes to contact@mydomain.com and I reply to the receiving end the mail should still be received from contact@mydomain.com.

I forward my work email to my Gmail and I want to respond automatically without having to select my work email from there.  How automatically to respond from the email where I received mail from automatically?


I can't figure out how to write the path of a folder that includes spaces in its name (in Terminal).  I tried:  cd /path/path/path/"A Folder"/file  cd /path/path/path/'A Folder/file  cd /path/path/path/A_Folder/file   but they all return the error through the terminal:  [command]: cannot access '/path/path/path/A Folder/file' No such a file or directory    I can still access it through steps like so:  cd /home cd user cd Desktop cd "Bash Programming" bash Example

I want to enter the following folder in the terminal:  Milano, Torino (Jan)-Compressed   How should I write the command cd to enter this directory?  Spaces and several other special characters like \, *, ), ( and ? cause problems when I try to use them in the command line or scripts, e.g.:    $ cd space dir bash: cd: space: No such file or directory  $ cat space file cat: space: No such file or directory cat: file: No such file or directory  $ cat ( bash: syntax error near unexpected token `newline'  $ echo content >\ > ^C  $ ls ? (  )  *  ?  \   How do I enter file or directory names that contain special characters in the terminal in general?


How many functions exist where their derivative is equal to the original function. For example:  $y = 0$ and $\frac{dy}{dx} = 0$  $y = e^x$ and $\frac{dy}{dx} = e^x$  Are there any other examples of these?

I was wondering on the following and I probably know the answer already: NO. Is there another number with similar properties as $e$? So that the derivative of $\exp(x)$ is the same as the function itself. I can guess that it's probably not, because otherwise $e$ wouldn't be that special, but is there any proof of it?


I have a camera and I want to move it with the mouse and also move a character, but when I try to move the character it moves to another. I don't know how to explain better. XD. Please help. Thanks.

How would I go about creating a 3D MMORPG Mouse Look? I have created a 3D Space Rpg that is almost finished with success so far. However, I didn't have a clue, how I would attempt to make a Mouse Look method where if a user right clickes and then holds the right mouse button and moves it around the camera moves around with the mouse. The camera can not move away from your character/ship, it should act as if the character/ship is it's origin and that it rotates all around the origin.  I don't mind coding this with python either. Advice is welcome!


I use Firefox to log into my Stack Exchange account(s) and the login handover between Exchanges works well - for vanilla Firefox.  A while back, I installed the  add-on for Firefox. (An absolutely superb plugin, I highly recommended it).   For sites that pass credential cookies between affiliated domain/sites (and where I want this to happen), I usually just add the applicable domains to the plugin's whitelist, after examining the  log.   However I can't seem to cover the whole chain involved in an inter-Exchange login handover. I currently have stackexchange.com, openid.stackexchange.com and my topic specific exchange domains white-listed. But I get asked for login credentials. Oddly enough if I back-navigate then forward-navigate from that screen I'll be logged in from cookies correctly.  This behaviour can be pretty easy reproduced with a Firefox browser with Self-Destructing Cookies add-on installed (and any cookie manager add-on for easier cache control).

I work behind an really annoying firewall, and I just want the net admin to add all the SE websites to the whitelist. Right now I've lost access to Stack Overflow's authentication, but not Meta's... so I have to come here before I log in there.  It's driving me nuts. Basically I just want to add an exclusion rule for all SE domains; not only the website domains, but also the content domains such as gravatar.com, quantserve.com, the domain that holds static content, etc...


I have two columns in a top-aligned frame which I want to be top-aligned as well. One column is an itemize environment, the other column  includes a graphic via includegraphics.  I read in the beamer manual that the T option should be used when strange things happen. This is why I preferred to have T as a default option, but that is not a good idea as it does not result in proper top-alignment.   See the following example:  \documentclass{beamer}  % dummy text macro \newcommand{\mylipsum}{bla bla bla bla bla bla bla bla bla bla bla bla bla bla}  \begin{document}  \begin{frame}[t]{A frame with 2 \texttt{columns}: \texttt{itemize} + \texttt{figure} }     \begin{columns}         \begin{column}{.5\textwidth}             \begin{itemize}                 \item first item \mylipsum                 \item second item \mylipsum                 \item third item \mylipsum                 \item fourth item \mylipsum             \end{itemize}         \end{column}         \begin{column}{.5\textwidth}             \includegraphics[width=\textwidth]{test_image.png}         \end{column}     \end{columns} \end{frame}  \begin{frame}[t]{A frame with 2 \texttt{columns [T]}: \texttt{itemize} + \texttt{figure} }     \begin{columns}[T]         \begin{column}{.5\textwidth}             \begin{itemize}                 \item first item \mylipsum                 \item second item \mylipsum                 \item third item \mylipsum                 \item fourth item \mylipsum             \end{itemize}         \end{column}         \begin{column}{.5\textwidth}             \includegraphics[width=\textwidth]{test_image.png}         \end{column}     \end{columns} \end{frame}  \end{document}   Surprisingly, the case with the option T results in worse top-alignment, as can be seen when comparing the two figures (adding T actually shifts the columns down...).     Why is the option T shifting the columns down and what am I missing here?  I am not sure if it plays a role, but here are the versions of beamer and XeTeX I am using (according to the output when compiling with xelatex):  This is XeTeX, Version 3.14159265-2.6-0.99992 (TeX Live 2015/Debian) [...]  LaTeX2e <2016/02/01> [...] Document Class: beamer 2015/01/05 3.36 A class for typesetting presentations (rcs-revision 8a39122e1f63)   Edit: I do not think that this question is a duplicate of  as suggested: First of all, none of the answers solves the problem presented here and the problem here is specifically about the weird behavior of the T option.

According to section 3.10 of the beamer manual, the t option top-aligns either every frame (when used as a class option) or a single frame (when used as optional argument of a frame environment). According to section 12.7, t can also be used to top-align the columns of a columns environment (a multi-column area within a frame). However, I didn't succeed to combine the two tasks, i.e. to top-align columns within a top-aligned frame. Did I miss something? How can the correct alignment be achieved?  Note: For columns, there's also a T option that (quoting section 12.7) should be tried "[i]f strange things seem to happen in conjunction with the t option". Adding T to the second column comes close to the desired result, but doesn't achieve it (the second column is positioned somewhat higher than the first column).  \documentclass{beamer}  \begin{document}  \begin{frame}[t]{Frame title}   \begin{columns}[t]     \begin{column}{0.5\textwidth}       \begin{itemize}       \item First column, first item       \item First column, second item       \end{itemize}     \end{column}     \begin{column}{0.5\textwidth}% Alternative A doesn't work %     \begin{column}[T]{0.5\textwidth}% Alternative B comes close       \begin{itemize}       \item Second column, first item       \end{itemize}     \end{column}   \end{columns} \end{frame}  \end{document}   EDIT: Thanks to Stefan for posting a workaround solution. I'm still interested in why such a workaround is necessary resp. why top-aligned columns work within centered frames by default. Is this a bug in beamer?


I have a problem. I  deleted some gnome packages , and now Ubuntu won't work as it should.  Plus i  installed some programs for system tweak(new look of icons etc) and delete them and only left Ubuntu Tweak . I log in system and i cross with mouse over icons in slide-bar and name of icons stays but won't go away ... and desktop picture won't show up ... but 2d Ubuntu work ok but my desktop won't responding to left and right mouse clicks(marking,meny) ... ! And i can not see desktop icons but when i go in nautilus and go to home/desktop i see desktop  icons!?  I  clean unnecessary programs and they left of with Ubuntu Tweak and now unity work but and i can change desktop background picture but still can not use desktop shortcuts on desktop.  I always check out manually for updates but it is still the same.   How to reinstall Unity to the latest version without reinstallation of complete Ubuntu .Txk. More you can find here:

I tested out Unity 5, and of course, it broke things, so I tried downgrading by    sudo apt-get install ppa-purge sudo ppa-purge ppa:unity-team/staging   It removed Unity completely.    apt-get install unity   seemed to work, but the login screen now offers only Gnome.  How do I get back to Unity 4?


I have written the following pattern to match an empty paragraph at the end of HTML:  But when I try the following Python code, the result is None html_desc = '

' res = re.match('(
){1}(\s)*(
|
){0,9}(\s)*(<\/p>){1}(\s)*$', html_desc)  #  returns None  I am not able to understand the issue.

What is the difference between the search() and match() functions in the ?  I've read the  (), but I never seem to remember it.  I keep having to look it up and re-learn it.  I'm hoping that someone will answer it clearly with examples so that (perhaps) it will stick in my head.  Or at least I'll have a better place to return with my question and it will take less time to re-learn it.


Today I get a new fresh copy of my Ubuntu 12.04 32Bit. I install ubuntu-restricted-extras from terminal and all was okey. But when I try to open youtube, it says that I need to install flash plugin.  I thought the flash plugin would automatically install with restricted extras. Next I tried to do with "sudo apt-get install flashplugin-installer", but come up with following messages.  Reading package lists... Done Building dependency tree        Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  flashplugin-installer : Depends: libnss3-1d but it is not going to be installed                          Depends: libnspr4-0d but it is not going to be installed E: Unable to correct problems, you have held broken packages.   Anyone could please help me how can I overcome this problem.

Occasionally, when I'm installing stuff, I get an error like the following:  Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  package1 : Depends: package2 (>= 1.8) but 1.7.5-1ubuntu1 is to be installed E: Unable to correct problems, you have held broken packages.   How can I resolve this?


root@test-2:/usr/local# mysql -u root -H 192.168.x.xxx -p Enter password: ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)

I just can't seem to figure this one out.  I want to use the command line to connect to a MySQL database residing on another server.  I went ahead and created the username and password for the user.  I have also granted all privileges on that user for that database.  When using the command: mysql -h <hostname> -u <username> -p, I get the following error:  ERROR 1045 (28000): Access denied for user '<username>'@'<local_machine_hostname>' (using password: YES)   The problem is that it keeps appending the current machine's hostname into the username.  Obviously, that user@<local_machine_hostname> is not correct.  It doesn't matter what I type.  For instance, if I type:  mysql -h <hostname> -u '<username>'@'<hostname>' -p   It does the same, only in the error output, it says:  Access denied for user '<username>@<hostname>'@'<local_machine_hostname>'   Is there a setting in a configuration file which is allowing this to happen?  It's really quite annoying.  I need to set up a tikiwiki server, and it cannot connect because during the step where you set up mysql, it keeps appending the local machine's hostname to the mysql login name.


I'm currently developing a custom activity for Journey Builder but have hit an issue I can not resolve.  The activity is appearing in Journey Builder and can be added to an interaction however when it runs, all of the contacts within the DE defined fail with the following error;     Failed - ExactTarget.JourneyBuilder.Activities.RestActivity.ContactKey: Error binding data bound member.   Googling hasn't thrown up much nor has SFMC documentation. The problem also occurs with the Hello World example on ExactTarget's public Github which makes me think it might be a configuration issue rather than the activity itself but if anyone can offer any suggestions it would be hugely appreciated!  So far...   Activity has no in/out arguments. It simply outputs to console.log whenever the save/validate/publish/execute endpoints fire Granted full read/write access in AppCenter Ensured the contact model has been configured with a root data DE (Sandbox_Customer) that relates to a Contact Key Ensured Contact Configuration > Email has been setup correctly with the email address from the Sandbox_Customer DE Ensured contacts exists in both subscribers and the Sandbox_Customer DE Ensured the journey contact entry is set as multiple Followed the suggestions in this question -

I created a Journey Builder Interaction and turned it on to TEST mode.  The Event Source for the interaction is a sendable Data Extension which is updated (via the API) every time someone new signs up through our website.  Contacts who do not already exist in 'All Subscribers' fail to enter the Journey Builder Interaction, and this is the error thrown:  Failed - ExactTarget.InteractionStudio.Activities.AllowMultipleDecision.ContactKey: Error binding data bound member.   Question #1: Does a contact have to exist in All Subscribers to be accepted into an interaction?  Question #2: How can I add contacts to All Subscribers when they first flow through Journey Builder?


Hi i have a ps4 slim it is not connect to the controller i have tried with 5 different controllers and the orange light comes and it does not connect. I have tried the hold the power off button till it beeps twice and unplug it and turn it on method to no luck. When putting it into safe mode the controller does work but when i restart it it doesn’t work. I factory wiped it in safe mode incase it would fix it and it did nothing and now its stuck on the connect dual shock 4 screen with the PlayStation big mistake as i could have used a keyboard before. I need help asap as i will end up selling the console as spares and feel like its a easy fix.i have tried everything reset controller, different methods, different controller, different charging cables. Please help, Thanks

I was playing my PS4 two days ago and then packed it up with two controllers that were both connected to this PS4.   I got to where I was going, set everything up and now the controllers won't connect. They show pulsing orange when they plug in, but when I hit the PS Button to connect, it blinks white 1-2 times and goes back to orange.   I have tried resetting them both.  Can anyone help?


How do plants like green onions seem to grow forever when put in jar of water?  I understand that plants get a lot of their carbon from the air (as per ) but surely they need more than just carbon to grow new leaves.  The answer in the linked question mentions that plants in general get their mass from sources like water and nutrients like nitrogen and phosphorous, and ions.  However, if a plant is growing directly in [distilled] water where will it get those nutrients (like phosphorous and the ions) from?  Where does that extra mass come from?

I remember hearing that trees and other plants actually obtain a large amount of their mass from the carbon floating in the air, not the ground beneath them. Does the makeup of air actually contain enough carbon to support this theory, and is a tree's surface area actually large enough to obtain the amount of carbon it needs directly from the air?


In his book Astrophysics for People in a Hurry, Neil de Grass Tyson starts of with the Big Bang and narrates on what (probably) happened within the first moments of our universe. He further states (p. 26)      By now, one second of time has passed. The universe has grown to a few light years across, about the distance from the Sun to its closest neighboring stars.   Q: Wouldn't this mean that by that means, the universe expanded vastly faster than the speed of light?

just after the Big Bang and before inflation the currently observable universe was the size of a coin. One millionth of a second later the universe was the size of the Solar System, which is an expansion much much faster than speed of light. Can space expand with unlimited speed?


I am aware of the problems of arithmetics with floats. But still I want to add two floats and have an exact result.  private float add (float f1, float f2) {   return (f1 + f2); } float f1 = 0.3f; float f2 = 0.4f; float f3 = add(f1,f2); Log.d("OUT","f3="+f3);   gives me float3=0.70000005  I really need the result to be 0.7. I know why it isn't, but what is the most efficient way to get my result?

public class doublePrecision {     public static void main(String[] args) {          double total = 0;         total += 5.6;         total += 5.8;         System.out.println(total);     } }   The above code prints:  11.399999999999   How would I get this to just print (or be able to use it as) 11.4?


As I understand it a blackbody spectrum is continuous – every possible frequency between the upper and lower bounds for that specific spectrum is there.  When we look at the sun (mainly hydrogen) or a tungsten filament (comprised of one element only) we observe a continous spectrum between the upper and lower frequency range for that object.  However, each element has its own unique discrete emission spectrum which I cannot see accounting for the continous range of frequencies seen in the black body curves.  What is happening at the atomic/subatomic level to cause generate the continuous observed spectra? The only explanation I can think of is that deexcitation of electrons is not the source of the light but rather it is the vibrations of the whole atom (which increase in frequency with temperature), and hence the oscillating electrons and protons within, that ‘generate’ the time-varying field which is the EM waves. I have already looked at all previous threads to related blackbody questions and this answer in below in quotations is the closest to what I am after but if this is correct more detail on how a collection of atoms have an increased range of energy levels would be appreciated! "In a hand waving sense, the black body radiation is also due to transitions between energy levels in the lattices of the bodies, but these are dense enough to become a continuum, as the approximation of the black body radiation shows, fitting the black body spectrum."

By conservation of energy, the solid is left in a lower energy state following emission of a photon.  Clearly absorption and emission balance at thermal equilibrium, however, thermodynamic equilibrium is a statement of the mean behaviour of the system, not a statement that the internal energy is constant on arbitrarily short timescales.  The energy has to come from somewhere during emission, and go somewhere during absorption.  Energy in a solid can be stored as kinetic and potential energy of electrons and nuclei, either individually or in collective modes such as phonons and plasmons.  In thermal equilibrium energy will be stored more or less in various forms depending on the temperature and material.  However, even if most of the thermal energy in a particular solid at temperature $T$ is stored in the form of phonons, it could be that phonons primarily interact with light indirectly via electrons, e.g. a phonon excites an electron in a phonon-electron interaction, which can interact with light via the EM field.  Given that light is an EM field, it makes sense to me that it is emitted and absorbed by charged particles.  The electron-photon interaction is probably dominant for visible and ultraviolet light, given that metals are opaque, while semiconductors and insulators are transparent to (visible and UV) light with energy lower than their bandgap. However, once you get into energies in the IR and below, or X-rays and above, other mechanisms apparently take over.  For example, on the high-energy end of the spectrum I've heard that gamma rays can interact directly with nuclear degrees of freedom, which is reasonable considering that gamma rays are emitted during a lot of nuclear reactions.  A review of  might give clues to important light-matter interactions over a broad range of wavelengths.  Whether all of the these processes are involved in blackbody emission is a somewhat different question.  What physical processes mediate energy transfer during blackbody emission, and in which energy ranges are the various processes dominant?


Let $f(x)\in R[x]$ be a zero divisor. How to prove that there is an element $0\neq a\in R$ such that $af(x) = 0$?    If $R$ has no nilpotent elements, it is easy. What about the general case? Can anyone help me? Thanks.

Let $R$ be commutative ring with no (nonzero) nilpotents. If $f(x) = a_0+a_1x+\cdots+a_nx^n$ is a zero divisor in $R[x]$, how do I show there's an element $b \ne 0$ in $R$ such that $ba_0=ba_1=\cdots=ba_n=0$?


I looking to convert a word document to latex. I know this has been asked before but this was a few years ago and there may be new software etc. I have seen the Word-to-latex software. Has anyone used this? Thanks for any help!

I am a final year graduate student and I have my thesis (about 350 pages) in Microsoft Word format. I would like to convert the document into a LaTeX "camera" ready PDF. Is there any easy way to do this? I am very new to LateX..


Spoilers for Deathly Hallows     When Voldemort killed Harry and went to the train station,   who or what was the skeleton under the white bench?

In Harry Potter and the Deathly Hallows, while Harry is in Kings Cross he sees something like a small child, which is the fragment of Voldemort's soul that was attached to him.     He recoiled. He had spotted the thing that was making the noise. It had   the form of a small, naked child, curled on the ground, its skin raw and rough, flayed-looking, and it lay shuddering under a seat where it had been left, unwanted, stuffed out of sight, struggling for breath.      He was afraid of it. Small and fragile and wounded though it was, he did not want to approach it. Nevertheless he drew slowly nearer, ready to jump back at any moment. Soon he stood near enough to touch it, yet he could not bring himself to do it. He felt like a coward. He ought to comfort it, but it repulsed him.      Harry Potter and The Deathly Hallows   Once Harry returns to the world of the living, that part of Voldemort's soul stays in limbo. Is this what happens to all fragments of someone's soul if he has divided his soul by creating a Horcrux? Does that mean that Voldemort's soul however crippled will stay in limbo or when all parts of his soul die, so does he?


I understand in theory how the common modulus attack works (as described here: )  Though, I did not understand completely how it worked with a negative $s_i$. Since $e_bs_1+e_cs_2=1$ one of the $s_i$ will be negative, so when I calculate $C_j^{s_i}$ it will be a fraction and not out of $\mathbb{Z}$.  From what I learned from the comments the trick is to calculate $(C_j^{-s_i})^{-1}=C_j^{s_i}$ instead. That way $-s_i$ is positive and $C_j^{-s_i}$ can be computed easily as well es the inverse $(C_j^{-s_i})^{-1}$ (using the Extended Euclidean algorithm). This solves my problem.  (I edited this question to specify my problem, answer it and to explain how it is different from  in the hope that it won't be marked as duplicate anymore.)

I am struck with the following problem:  Let Alice, Bob, Chris and Eve communicate over a public network. They encrypt all messages they send using RSA system. Bob and Chris have the RSA modulus $n_B$ and $n_C$ respectively with $n_B$ = $n_C$ But different public encryption exponents: $e_B \neq e_C$. Suppose $\gcd(e_B, e_C)=1$, and that Alice sends the same secret message to Bob and Chris. Show how Eve can decipher the message.


I have a very simple situation that I can't seem to resolve. I want to centre the text vertically to the FontAwesome icon. But I can't for the life of me figure out why it's not centering.  I have tried other answers but none seen to utilise the :before CSS definition which is a very accepted way to implement icons.  Here's my code:   #rk-lesson-menu {     display: inline-block;     width: 100px;     height: 60px;     float: right;     text-align: center;     border-left: 1px solid #DDD;     line-height: 60px;     vertical-align: middle;     text-decoration:none } #rk-lesson-menu:before {     font: 28px/60px fontawesome;     content: "\f0c9";     padding-right: 3px; } <link href="//maxcdn.bootstrapcdn.com/font-awesome/4.2.0/css/font-awesome.min.css" rel="stylesheet"/> MENU

Why won't vertical-align: middle work?  And yet, vertical-align: top does work.   span{   vertical-align: middle; }
      Doesn't work.


Trying to have a levitation effect applied to any player when and only when that player holds a specific item (in this case, a renamed feather).  Pre-1.13 it worked using a string of command blocks that tagged a player using scoreboards and applied the effect to that player, but like many of the command blocks in this world, the 1.13 update broke them.  I realised that I should be able to use the execute if command, but I cannot seem to get it to work - it seems to either apply it to the player closest to the command block (even when another player is the only holding the item) or it applies it to all players.  Command currently looks like this:  execute if entity @a[nbt={SelectedItem:{id:"minecraft:feather",tag:{display:{Name:"\"Levitator\""}}}}] run effect give @p minecraft:levitation 1 4  I tried modifying that by nesting it with various combinations of execute as and execute at, but it still seemed to have the same issues (it would always execute relative to the command block not the player).  Any ideas on how to get this to work?

I'm trying to make a command block that spawns an item in front of you if you are holding an item with a specific name. I've got these two working scripts;  /testfor @p[r=10] {Inventory:[{tag:{display:{Name:"Item Name"}}}]}  /testfor @p[r=10] {SelectedItemSlot:0,Inventory:[{Slot:0b,id:"minecraft:diamond_sword"}]}   but I can't get them together. The block should only look for an item in the active slot.


I am trying to add text in the the <textarea> when an on change event occurs.   It works perfectly fine in the first change event. But when I delete the text inside the text area and preform another change event it does not work add the text anymore?  I am really confused on why its not working. Below is a snippet of what I am trying to accomplish.     $("#test").on("change", function() {    $("#textarea_test").text("Hello");  }); <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> <select name="test" id="test">   <option value="Test1">Test 1</option>   <option value="Test2">Test 2</option>  </select>  <textarea name="textarea_test" id="textarea_test" cols="30" rows="10"></textarea>

I am attempting to set a value in a textarea field using jquery with the following code:  $("textarea#ExampleMessage").attr("value", result.exampleMessage);   The issue is, once this code executes, it is not altering the text in the textarea?  However when performing an alert($("textarea#ExampleMessage").attr("value")) the newly set value is returned?


What we have: extremely cheap dedicated server with configured corp mail server. Unreliable work plus it has permanent troubles with mails verifying (configured by another person).  What we need: at least several important addresses with 99% reliability.  Idea how to reach that: Pay to mail provider (right now i'm thinking about G Suite) for several high-reliable addresses, leaving every other user on dedicated server.  So, what we must get at the end - two MX servers, same mail domain, each server handles it's own addresses. I'm hardware engineer, so that part of configuring is totally unclear for me - is it possible to make such configuration? I know that it's possible to add second MX server with same address list for redundancy, but what about my variant? Is it even possible somehow to make routing inbound mails between different servers? (as i understood outbound mails won't be a problem at all).  For saving your time - i know that normal reconfiguration of dedicated server or full migration to G Suite is much more easier, but sadly both options aren't for me :(  Also question for G Suite experienced users - is it possible to setup some sort of mail relaying in G Suite? For example, i'm placing 1 MX record with google MX server in domain. If letter arrives at a@domain.com - it goes into G suite address, and if it's b@domain.com - google MX relays it to another server.com. I'm not so good in MX technology, so maybe my question is dumb :) But such solution will also work well in my case.

I would like to configure 2 MX records :  - One MX record that identifies an email server to the domain @mycompany.com that will handle all of the emails except one email - Another MX Record that will redirect to another email server if the address email is: me@mycompany.com  Is it possible? If yes, how can I achieve it?  Thanks,  Fabien


Let $ (X,d) $ be a metric space and $ A \subseteq X $ be compact.    Prove that for any $ y \in X $ there exists $ x \in A $ so that $d(y,x) = d(y,A)$ where $ d(x,y)=|x-y| $.   Since A is compact it is covered by finitely many balls of $X$.   So $ A \subseteq \bigcup_{j = 1}^N B(x,j)=B(x,N) .$  Let $y \in A$. Then $y \in B(x,N)$ and so $d(x,y) < N$.  And then I'm stuck on how to approach this problem.

Let $(X, d)$ be a metric space. Is the function $x\mapsto d(x, z)$ continuous? Is it uniformly continuous?


If I will accept the Windows 10 upgrade from Windows 7, will all my games and programs stop working? How does it work?   Do they just give you a link to download it and then you do the rest (one) or they somehow replace your Windows 7 with Windows 10 (two)?  If number one, then no problems.  If number two, then will that keep all your games and programs currently installed and will they all work ok?

I have Windows 8.1 Update, if I update to Windows 10 when it becomes available what is going to happen to my data and apps?  Of course I have to do a backup, but I wonder if the data will be overwritten or not.


Is their a way to check an application exists before I write in the code to create the object   I know this is install and I can use it but what if I want the program to check first ?  Set objOutlook = GetObject("Outlook.Application")

I want to check if an app is alredy installed through launch conditions.If yes i want to exit the installer,if no the installation should continue.Could anyone tell how to achive this in c# installer?.  Regards, Harsh Suman


If I execute the following code: l = ["A", "B", "C"] for i in range(len(l)):     e = l.pop(0)     l.append(e)     print(l)  The output is as expected and iterates the list as expected placing the first element at the end: ['B', 'C', 'A'] ['C', 'A', 'B'] ['A', 'B', 'C']  HOWEVER, if I attempt to build a data structure to store the lists: fl = [] l = ["A", "B", "C"] for i in range(len(l)):     e = l.pop(0)     l.append(e)     fl.append(l) print(fl)  The output is not as expected: [['A', 'B', 'C'], ['A', 'B', 'C'], ['A', 'B', 'C']]  Can anyone please explain this?

I needed to create a list of lists in Python, so I typed the following: my_list = [[1] * 4] * 3  The list looked like this: [[1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 1, 1]]    Then I changed one of the innermost values: my_list[0][0] = 5  Now my list looks like this: [[5, 1, 1, 1], [5, 1, 1, 1], [5, 1, 1, 1]]    which is not what I wanted or expected. Can someone please explain what's going on, and how to get around it?


First of all, I saw few similar questions here but most of them address the question of why, when I want to address a question of HOW. Also one question is addressing the same problem but I find it's formulation rather complicated and this makes it difficult to understand the question and answers. When the problem can be described and visualized in much simple way:  Let's consider a spaceship floating under the Earth. There is a source of light and at time 0s the light will reach some point on Earth and the end of spaceship:  Then, after 1 second have passed on Earth, we will see the following picture:   As we can see, relatively to the Earth the light have made a distance of 300,000 km in 1 second. But relatively to the spaceship the distance is half of that. When explaining how this can happen, usually they say that clock on the rocket will tick slower so speed calculated by folks on the spaceship is the same.   And it sounds believable until you imagine an other source of the light from an other end of the scene:  In this case by the same time the light from an other source have made a distance of 450,000 km. So if we use the same time as we did in previous case, the speed must be different.  So how can you imagine\describe the same speed for light from both sources and for both reference frames?

I was told that the Galilean relative velocity rule does not apply to the speed of light. No matter how fast two objects are moving, the speed of light will remain same for both of them.   How and why is this possible?   Also, why can't anything travel faster than light?


This is an exercise in Ravil Vakil's Algebraic Geometry notes labeled hard  Let $f: A\rightarrow B$ be a morphism in an abelian category. Then $f$ factors through a morphism $f':A\rightarrow \operatorname{im}(f)$ (recall that $\operatorname{im}(f)$ is the (domain of the) kernel of the cokernel of $f$).   Why is $f'$ an epimorphism? That is why does $g\circ f'=0$ imply $g=0$ for any $g: \operatorname{im}(f)\rightarrow C$   ?

How can I verify the following statement?     The image of a morphism $f : A \longrightarrow B$ is defined as $\text{Im}(f) = \text{Ke}r(\text{coke}r f)$ whenever it exists (e.g., in every abelian category). The morphism $f : A \longrightarrow B$ factors   uniquely through $\text{Im} f \longrightarrow B$ whenever $\text{Im} f$ exists, and $A \longrightarrow \text{Im} f$ is an epimorphism and a cokernel of ker $f \longrightarrow A$ in every abelian category.


I have a string like this 67,73,89. I want to explode all the value and compare each value. In php  I can do it like this  <?php $marks = "67, 73, 89"; $explode = explode(", ",$marks); foreach($explode as $mark){     if($mark > 80)     echo $mark."<br>"; } ?>   Can anyone give me the mysql code so that i can select all the student roll number where marks contains atleast one value > 80. You can use mysql explode function like this...  CREATE FUNCTION explode(str VARCHAR(255), delim VARCHAR(12), pos INT) RETURNS VARCHAR(255) RETURN REPLACE(SUBSTRING(SUBSTRING_INDEX(str, delim, pos),        LENGTH(SUBSTRING_INDEX(str, delim, pos-1)) + 1),        delim, '');   Table structure is  ╔═════════╦═══════╦══════════╗ ║ Roll_No ║ Name  ║  Marks   ║ ╠═════════╬═══════╬══════════╣ ║       1 ║ John  ║ 67,73,89 ║ ║       2 ║ Bob   ║ 75,69,80 ║ ║       3 ║ Smith ║ 62,79,92 ║ ╚═════════╩═══════╩══════════╝

I have to create a report on some student completions. The students each belong to one client. Here are the tables (simplified for this question).  CREATE TABLE  `clients` (   `clientId` int(10) unsigned NOT NULL auto_increment,   `clientName` varchar(100) NOT NULL default '',   `courseNames` varchar(255) NOT NULL default '' )   The courseNames field holds a comma-delimited string of course names, eg "AB01,AB02,AB03"  CREATE TABLE  `clientenrols` (   `clientEnrolId` int(10) unsigned NOT NULL auto_increment,   `studentId` int(10) unsigned NOT NULL default '0',   `courseId` tinyint(3) unsigned NOT NULL default '0' )   The courseId field here is the index of the course name in the clients.courseNames field. So, if the client's courseNames are "AB01,AB02,AB03", and the courseId of the enrolment is 2, then the student is in AB03.  Is there a way that I can do a single select on these tables that includes the course name? Keep in mind that there will be students from different clients (and hence have different course names, not all of which are sequential,eg: "NW01,NW03")  Basically, if I could split that field and return a single element from the resulting array, that would be what I'm looking for. Here's what I mean in magical pseudocode:  SELECT e.`studentId`, SPLIT(",", c.`courseNames`)[e.`courseId`] FROM ...


$$\int_0^\infty x\left(\log\left(\frac1{x^2}\right)\right)^n dx$$  put $\log\left(\frac1{x^2}\right)=y^{1/n}$  $$I=\frac{\ln10}{2n}\int_{-\infty}^\infty10^{-y^{1/n}}y^{1/n}dy$$  put $10^{-y^{1/n}}=e^{-t}\implies$  $$I=\frac1{(2\ln10)^n}\int_{-\infty}^0e^{-t}t^ndt+\frac1{(2\ln10)}\int_0^\infty e^{-t}t^ndt$$  $$I=\frac1{(2\ln10)^n}\int_{-\infty}^0e^{-t}t^ndt+\frac{\Gamma(n+1)}{(2\ln10)}$$  I want to know how can I evaluate the first integral in the last step of my turn I used some substitutions so i get two integrals one of them converted to the formula of gamma function but the second could not be so because the domain of integration is different ? $n$ is a natural number


I have geo coordinates from Google Maps which are WGS84 in decimal degrees for India. I want to calculate the distance between them in meters. Which projection should I use?  I use ArcMap 10.4.1.

I want to create spatial data for entire India.  Usually I use WGS84 as GCS and UTM zones for PCS in the places in India, but when I have to create the spatial data for entire India, I get confused which geographical coordinate systems and projected coordinate system will be suitable.  What are suitable ones?


I was running Windows 7 Pro (32 bit) OS on my Dell Dimension 9100. I attempted to load (side by side) Ubuntu 14.04.1 desktop.  The install appeared to work properly into a 19 GB partition.  When completed, the restart (reboot) brought up the following message.  error: no such device: e4958c47-7613-4ca4-82d6-b80ffc2b2148 Entering rescue mode... grub rescue>   Even after removing the Ubuntu with OS-Uninstaller, the above message returns on every boot.  So how do I get back to a Windows 7 boot?

I have absolutely no experience with Linux, and I desperately need to get my computer back up and running again with Windows.  How do I remove Ubuntu and reinstall Windows?    Editor's note: many of the answers are about removing Ubuntu from dual-boot but keeping Windows (which is a bit complicated), while other answers are about removing Ubuntu from single-boot (which is easy: basically just format the disk while installing Windows). The question as written is ambiguous between dual-boot or single-boot.


I have two classes  I am not sure why this is erroring. In eclipse there are no red underlines.  Main:  package com.example;  public class Main {     public static void main(String[] args) {         Week myWeek = new Week(Week.days.FRIDAY);         System.out.println(myWeek.Today.toString());     } }   Week:  package com.example;  public class Week {     public static enum days {         SUNDAY,         MONDAY,         TUESDAY,         WEDNESDAY,         THURSDAY,         FRIDAY,         SATURDAY     }      static final days[] order = {         days.SUNDAY, days.MONDAY, days.TUESDAY, days.WEDNESDAY,          days.THURSDAY, days.FRIDAY, days.SATURDAY     };     days Today;      Week(days toSetTo){         @SuppressWarnings("unused")         days Today = toSetTo;     } }   the error is on Main.java:6

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


I have followed the installation steps   :  sudo sh -c 'echo "deb https://atlassian.artifactoryonline.com/atlassian/hipchat-apt-client $(lsb_release -c -s) main" > /etc/apt/sources.list.d/atlassian-hipchat4.list' wget -O - https://atlassian.artifactoryonline.com/atlassian/api/gpg/key/public | sudo apt-key add - sudo apt-get update sudo apt-get install hipchat4   But after sudo apt-get update I get :   .... Fetched 5,092 kB in 6s (794 kB/s)                                                                                W: Failed to fetch http://dl.google.com/linux/chrome/deb/dists/stable/Release  Unable to find expected entry 'main/binary-i386/Packages' in Release file (Wrong sources.list entry or malformed file)  W: Failed to fetch https://atlassian.artifactoryonline.com/atlassian/hipchat-apt-client/dists/precise/main/binary-amd64/Packages    W: Failed to fetch https://atlassian.artifactoryonline.com/atlassian/hipchat-apt-client/dists/precise/main/binary-i386/Packages    E: Some index files failed to download. They have been ignored, or old ones used instead.   I have already followed this exacts steps with success on a ubuntu 14.04 machine.     Edit 1 -  on 64 bit, I get following error  Get:2 https://atlassian.artifactoryonline.com precise/main Translation-en_US [80 B] Err https://atlassian.artifactoryonline.com precise/main amd64 Packages                                                                           Err https://atlassian.artifactoryonline.com precise/main i386 Packages                                                                            Ign https://atlassian.artifactoryonline.com precise/main Translation-en_US                                                                       Ign https://atlassian.artifactoryonline.com precise/main Translation-en                                                                          W: There is no public key available for the following key IDs:                                                                                1397BC53640DB551 W: Failed to fetch         https://atlassian.artifactoryonline.com/atlassian/hipchat-apt-client/dists/precise/main/binary-amd64/Packages    W: Failed to fetch  https://atlassian.artifactoryonline.com/atlassian/hipchat-apt-client/dists/precise/main/binary-i386/Packages    E: Some index files failed to download. They have been ignored, or old ones used instead. $ sudo apt-get install hipchat4 Reading package lists... Done Building dependency tree        Reading state information... Done E: Unable to locate package hipchat4

I have unistalled and reinstalled the Ubuntu Software Center as per info I found in a similar thread and I got the same response about line 91 or something like that.  I just tried to upload a screen shot but since I'm new it won't allow me to.  I also can not figure out how to cut and paste anything so I have to hand type what the error screen says, both when I attempt to open the software center and nothing happens, when I try to enter commands into the terminal to uninstall, reinstall, whatever I get the same following:  COULD NOT INTITIALIZE THE PACKAGE INFORMATION An unresolvable problem occured while initializing the package information Please report t:his bug against the 'update-manager' package and include the following error message: 'E: Malformed line 91 in source list/etc/apt/sources.list (dist parse)  E: The list of sources could not be read.,  E: The package list of status file could not be parsed or opened.   How do I report bugs?  What can be done about this.  I have searched and everything everyone says to do leads me back to the same line error message.  So, I don't know how to get to line 91 in the source list; to tell you what it says. Sorry, I'm really new to this. That is what I need is to find out how to get there and fix what it says. I would really like to NOT have to re partition my hard drive and start from scratch, so I'm really looking forward to getting this problem solved. I need to be able to install new software.


will converting raw files to jpeg be the same as taking a jpeg photo to begin with? or will I keep my raw quality converting it to jpeg post shoot?

I'm curious to see some real examples of where simply capturing the same photo in RAW (and being processed by someone who can do it justice) has significantly improved the photo at the end of the process.  I understand what RAW is and why you might want to use it over JPEG, however, I'd like to actually see some examples where it has allowed for a better result. More control over tone, conversion from the more detailed data to 8-bit RGB etc.  Does anyone have or know of some processed RAW+JPEG shots for exact comparison?


Consider the equation $$2\tan(2x) = 3\cot(x)$$ What are the $x$ values (in degrees) that satisfy the equation for $0^\circ \leq x \leq 180^\circ$?  When I try to solve it using the identity of $\tan(2x)$, I get two solutions, which are $33.2^\circ$ and $146.8^\circ$. However, there appears to be a 3rd solution of $90^\circ$; I get this value after graphing the LHS and RHS on Desmos but should it be a valid solution as $3\cot(90^\circ)$ is undefined?

The question is  Find the solutions to the equation $$2\tan(2x)=3\cot(x) , \space 0<x<180$$  I started by applying the tan double angle formula and recipricoal identity for cot $$2* \frac{2\tan(x)}{1-\tan^2(x)}=\frac{3}{\tan(x)}$$ $$\implies 7\tan^2(x)=3 \therefore x=\tan^{-1}\left(-\sqrt\frac{3}{7} \right)$$ $$x=-33.2,33.2$$ Then by using the quadrants  I was lead to the final solution that $x=33.2,146.8$ however the answer in the book has an additional solution of $x=90$, I understand the reasoning that $\tan(180)=0$ and $\cot(x)$ tends to zero as x tends to 90 however how was this solution found? Is there a process for consistently finding these "hidden answers"?


I have a 401k from a company I no longer work at. It's worth about 70k.  What should I do with it?  Is there any way I can roll it into something that I can use as part of a down payment for a house in 1 year?  If not, what is the best option right now?

Are there any valid reasons to not rollover a former 401(k) when changing jobs?  I have several little ones that I never quite got around to rolling together - with an upcoming job change, should they all be combined into my new employer's retirement plan?  If not, what else might be considered?


I have this question in my mathematics textbook:  If $a$ and $b$ are positive integers such that $b > a$, when will $a^b = b^a$?  I had no clue where to start. So I looked at the answer:  If $a$ and $b$ are positive integers such that $b > a$, $a^b = b^a$ when $a = 2$ and $b = 4$. It is not easy to prove that this is the only solution; students are only expected to use guess and check to find a solution.  The answer provides no proof for the solution, or insight into the method for finding the solution, apart from a vague mention of "guess and check". I wish to find the (algebraic, if possible) proof for the question. So to sum up:  Given that $a > 0$, $b > 0$ and $b > a$, prove that the only solution of $a^b = b^a$ is that $a = 2$ and $b = 4$.

It's not too difficult to figure out that $x$ and $y$ can both be 1, and also $x$ can be 2 and $y$ can be 4 (and vice versa). But I can't rule out if there are other solutions. Does it have anything to do with inverse functions? Is there a way to see the solutions by graphing, or algebraically?


Let $F$ be a field. If $F^*$ is a cyclic group, must $F$ be a finite field? (It's well-known that if $F$ is a finite field, $F^*$ is a cyclic group).  Thank you in advanced.

Let $F$ be a field and $F^\times$ be its group of units. If $F^\times$ is cyclic, then show that $F$ is finite.  I'm a bit stuck. I know that I can represent $F^\times = \langle u \rangle$ for some $u \in F^\times$ and that we must have that $|F^\times| = o(u)$, where $o(u)$ denotes the order of $u$ in $F^\times$.  I tried assuming $o(u) = \infty$, but I'm not sure exactly where to go from there. I was wondering if I could get a hint.


When I asked my teacher that what is the acceleration at the centre of earth, he replied that it is 0 as when we move inside the earth, the effective mass decreases i.e. the mass that exerts gravitational force on us decreases and hence at the centre of the acceleration due to gravity is zero.  However when we reach at the centre of earth the radius is also zero  hence from the formula - GM/r^2 Where M is mass of earth and r is it's radius, by putting 0 in place of M and r , we get value of acceleration due to gravity = 0/0 which is an undefined quantity.  Even if my teacher was wrong, on Google, the answer for value of acceleration due to gravity is zero and the radius of earth at its centre is also zero so by the formula:- GM/r^2 putting 0 in place of r, we get GM/0  So we get GM/0=0  But GM/0 is again an undefined quantity.  I want ask how is acceleration due to gravity 0 when it is not permitted by the formula as the formula should also be satisfied in every case.

Would the effect of gravity on me change if I were to dig a very deep hole and stand in it? If so, how would it change? Am I more likely to be pulled downwards, or pulled towards the edges of the hole? If there would be no change, why not?


This user is shown to have a +6268 change in quarter reputation when the user doesn't have that much reputation in the first place. What's going on here?

What does the Change field represent on the  for SO? Refer to the highlighted areas in the image below:   Rank: the user's ranking for the selected time period (week, month, quarter, year) Change: +/- change representing... ??? Total Reputation: the user's total reputation [Time Period] Reputation: the user's reputation for the selected time period (week, month, quarter, year)  So what is the Change field measuring?


When I tried to update apt's local package index, I am getting an error  % sudo apt-get update Ign http://dl.google.com stable InRelease ... lots or repositories ... Ign http://archive.ubuntu.com ..... Fetched 2,628 kB in 34s (75.7 kB/s) Ign http://archive.ubuntu.com trusty/universe Translation-en_NZ     Fetched 2,628 kB in 34s (75.7 kB/s)  W: Failed to fetch http://dl.google.com/linux/chrome/deb/dists/stable/Release  Unable to find expected entry 'main/binary-i386/Packages' in Release file (Wrong sources.list entry or malformed file) E: Some index files failed to download. They have been ignored, or old ones used instead.   So trying to trace apt's flow of actions, I see  file: /etc/apt/sources.list.d/google-chrome.list contains  deb http://dl.google.com/linux/chrome/deb/ stable main   Im guessing this is what tells apt to try get fresh package lists from http://dl.google.com/linux/chrome/deb/.    Looking at the contents of the "failed "file: http://dl.google.com/linux/chrome/deb/dists/stable/Release hosted on googles repo server:   contains:  Origin: Google, Inc. Label: Google Suite: stable Codename: stable Version: 1.0 Date: Thu, 03 Mar 2016 22:43:39 +0000 Architectures: amd64 Components: main Description: Google chrome-linux repository. MD5Sum:  89704f9af9e6ccd87c192de11ba4c511 145 main/binary-amd64/Release  43ceb3a785b6dd436c53e9dbde008599 4164 main/binary-amd64/Packages  7ea2e6a029b4fedb4c1518f6465e577a 961 main/binary-amd64/Packages.gz  64235650d3cd442717b11560da225787 1197 main/binary-amd64/Packages.bz2 SHA1:  153199d8f866350b7853365a4adc95ee687603dd 145 main/binary-amd64/Release  02ca738529f7cc2effb3f4da95316726c15afd6f 4164 main/binary-amd64/Packages  8ecf917c5c7a93c9b3afb24a3b961d6bcd88bc33 961 main/binary-amd64/Packages.gz  b7756eaa63557380b74b15a379cb49f2d4dfc5b6 1197 main/binary-amd64/Packages.bz2    What is the purpose of this file? http://dl.google.com/linux/chrome/deb/dists/stable/Release How can I fix this error?    I will update this post if anyone needs anymore info

I am using Google Chrome 48.0 32-bit. Today when I launched Google Chrome, I got this message:    This computer will soon stop receiving Google Chrome updates because this Linux system will no longer be supported   I thought Ubuntu 14.04 is supported for five years, what's exactly happening here?  And on 64-bit Ubuntu, I get an error from Update Manager and apt-get update:  Failed to fetch http://dl.google.com/linux/chrome/deb/dists/stable/Release  Unable to find expected entry 'main/binary-i386/Packages' in Release file (Wrong sources.list entry or malformed file)   Some index files failed to download.   They have been ignored, or old ones used instead.


I am trying to understand the basics of QGIS following their online training manual but I can't find the processing toolbox anywhere in qgis 3.10.3 for mac.

I can't find the processing toolbox anywhere in QGIS3.10. I thought I just had to activate it but I can't find it under all plugins or installed plugins. Does anyone know where I can find it or how I can fix this problem? I've attached a picture of the plugin window and the main window.


I have polyline data (contour data),  the z value is in the attribute table. The shapefile does not have the z_value set in the geometry. I am able to get point data to work, but when I do the same process, I end up with a midpoint for the line with an xyz value. I need the line data to have a z value before I convert the shapefile (Feature class) to a DWG file for AutoCAD. I use ArcMap (ArcView 10.0) with not extra extensions and QGIS so either software will be fine.

I'm new to QGIS and working with GIS in general (student of architecture), so please bear with me.  I have obtained shapefiles with topographic curves of an ocean floor. My intention is to export these as CAD files and render as 3D models of the ocean floor in Revit. I have done this procedure earlier with terrain shapefiles. My problem now is that these files mapping depth does not contain z values, so when exporting them into CAD they are completely flat rather than 3D models.  The depth information in meter exists as attributes in the file (see attached image). What I want is to transform this depth value into real z coordinates for each line so that the curves have different heights when importing as CAD file in Revit.  Thankful for any pointers in the right direction.


I have a Toshiba flash drive that I'm trying to wipe clean, but the thing is that the files won't go away. I have tried everything:   the simple left click -> format, a message appears: windows can't complete the format process disk management and deleting the partition, once I create a new partition the files appear back as if nothing happened DISKPART command in CMD, once I hit clean it says the process was successful but the files are still there, it should be mentioned that CHKDSK doesn't show anything out of the ordinary third party software: mini partition tool, Rufus, easeus, I've tried wiping data by putting 0's which is an option in mini partition tool, but this doesn't seem to be solving anything virus scan with esetnod shows no signs of malware am    I missing something? is there anything I can do?

I have a 2 GB SanDisk MicroSD card.  I normally use this card in my Nikon camera but ever since I used it in a Brother printer, I cannot delete any of the files, write or format the card.  I've searched online, including SuperUser, but my problem seems unique in that I do not get any errors when deleting, writing or formatting card.  Nikon Camera:  Everything appears normal when using this card taking pictures... no errors when supposedly saving the photo.  However, when trying to view pictures, the camera reports that none can be found.   I can do a "Quick Format" within the camera'a Setup screens but the card is not formatted and no errors reported.   Brother Printer:  Scanning direct to this MicroSD card.  (this is the incident that "broke" the card)  First document scanned fine.  Every subsequent attempt since then always gives an "Out of Memory" error.  MacBook:  I am manually deleting the files without errors, but the next time I insert the card, the files re-appear.  SDFormatter:  I downloaded and installed the latest version of .  I am doing a "Overwrite Format" option, I get no errors, and the format completes with a success message.  However, all of the original files remain on the card!  I am using a MicroSD to USB adapter with the MacBook and a MicroSD to SD card adapter with the Nikon.  Clearly, based on all observations above, I cannot write to the card.  Weirdly, with the exception of the Brother, I just don't get any errors when writing.  It's like the card is locked, even though it cannot be locked without the hardware lock on the SD adapter, and I never get any "write protection" errors.  I suspect that a corrupted MicroSD card is the root problem, but here are my questions:   Why would I not get any errors when writing, deleting or formatting? What can I do or use to verify the hardware integrity and/or fix this card as needed?


I was trying to split a String into a String array using the split function but received the error:  Exception in thread "main" java.lang.NullPointerException at wdtbam.main(Main.java:16)   I was solving this problem at . My goal was to split the String into indexes of an array wherever a space was encountered and later parse that into Long type.  Here's my code  import java.util.*; import java.io.*; class wdtbam {     public static void main(String args[]) throws IOException     {         BufferedReader br = new BufferedReader(new InputStreamReader(System.in));         Scanner sc = new Scanner(br);         int t =sc.nextInt();         for(int i=1;i<=t;i++)         {             int n =sc.nextInt();             String a =br.readLine();             String b =br.readLine();             String c = br.readLine();             String cx[]= c.split(" ");  //the problem             long d []=new long[1234];             int y=0;             for(int j=0;j<=n;j++)             {                 d[j]=Long.parseLong(cx[j]);             }             for(int k=0;k<n;k++)             {                 if(a.charAt(k)==b.charAt(k))                 {                     y++;                 }             }             System.out.println(d[y]);         }     } }   I have been encountering this problem since long and it would be very appcreciable if someone could help me out.  EDIT:  I removed BufferedReader from my code and instead used only Scanner. I also tried to directly input the numbers into an array instead of inputing a string and later parsing it to an long array.   Here's my new code:  import java.util.*; import java.io.*; class wdtbam {     public static void main(String args[])     {         Scanner sc = new Scanner(System.in);         int t =sc.nextInt();         for(int i=1;i<=t;i++)         {             int n =sc.nextInt();             String a =sc.nextLine();             String b =sc.nextLine();             long d []=new long[1234];             int y=0;             for(int j=0;j<=n;j++)             {                 d[j]=sc.nextInt();             }             for(int k=0;k<n;k++)             {                 if(a.charAt(k)==b.charAt(k))                 {                     y++;                 }             }             System.out.println(d[y]);         }     } }   I am still getting an error. IDK why.  Please help I am really frustrated with JAVA right now.  Error:  Exception in thread "main" java.util.InputMismatchException     at java.util.Scanner.throwFor(Scanner.java:864)     at java.util.Scanner.next(Scanner.java:1485)     at java.util.Scanner.nextInt(Scanner.java:2117)     at java.util.Scanner.nextInt(Scanner.java:2076)     at wdtbam.main(Main.java:18)   BTW here's the problem I was trying to solve :

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


So, I'm creating a photo library and I created a method that when you click on a photo in the list, it should display a few properties of it such as caption, tags, and date. It's called handleList but it's throwing a null pointer exception when I click on a part of the list that's not populated. I had a line of code that should check whether an item was selected but I don't think it's working because the code under it is still being run and it's throwing null pointer exception because it's trying to draw data from a photo that isn't there therefore it's a null pointer exception. However, it does work when I click on a photo so maybe I have the wrong type of check. Any ideas on how to fix my code? I think I have to change the mouse event parameter or write a working check that checks is something is selected.   Here's the line where it breaks:  Date date1 = p.dop.getTime();   Here's the code below:       **  * This will populate photo labels based on if an item is selected  * @param e Mouse Click  */  public void handleList(MouseEvent e) {       if(photos.getSelectionModel().selectedItemProperty()!=null){            Photo p = photos.getSelectionModel().getSelectedItem();           DateFormat dateFormat = new SimpleDateFormat("MM-dd-yyyy");            Date date1 = p.dop.getTime();           String strDate1 = dateFormat.format(date1);            dateLabel.setText(strDate1);            deleteTag.getItems().clear();           tagList.getItems().clear();           for(Tag t: p.tags)           {               String s=t.name+"-"+t.val;               if(!deleteTag.getItems().contains(s))               deleteTag.getItems().add(s);               if(!tagList.getItems().contains(s))               tagList.getItems().add(s);           }              try              {                 UserList.write(userlist);              } catch (Exception i) {                 // TODO Auto-generated catch block                 i.printStackTrace();             }       }  }   can someone please explain why this line below isn't working:    photos.getSelectionModel().selectedItemProperty()!=null


I have installed the libboost-all-dev package, and cannot find the thread aware libraries I need inside my /usr/lib/ directory. (libboost_system-mt.a)  Are the library files that aren't suffixed with -mt thread aware? (As none of them are suffixed)

I am compiling a program which requires boost-thread-mt library. I have installed libboost-all-dev using sudo apt-get install libboost-all-dev but compiler says that it cannot find boost-thread-mt library. Is this library in some other package? Please guide me what i need to install for this.


After installing SQL Server 2019 CU2, SQL Server Agent starts consuming too much CPU resulting into skip job schedules.  Although the agent service is running but it looks like hang and didn't process / kick off any jobs.  Once I re-start the Agent service it starts working again (cpu = 0), but then again after some time 1-2 hours CPU intake in high and jobs do not run.  Is anybody else facing same issue with SQL Server 2019 CU2?  Any help would be much appreciated.  Thanks,

After installing CU2 our SQL server agent randomly stops working.  If you go to check on the status of the agent by opening Job Activity Monitor, it comes up blank for a while then throws an error:     Failed to retrieve data for this request.   (Microsoft.SqlServer.Management.Sdk.Sfc)      For help, click:         ------------------------------ ADDITIONAL INFORMATION:      An exception occurred while executing a Transact-SQL statement or   batch. (Microsoft.SqlServer.ConnectionInfo)            A severe error occurred on the current command.  The results, if any,   should be discarded. (Microsoft SQL Server, Error: 0)      For help, click:      Any clue what could be causing this?


The  has reached 75K. It increased from ~50K in the last two weeks.  I have a suggestion I would like to propose to resort the queue based on the amount of close votes.   So, if there are questions which already received 4 votes then move them up the queue so we only need 1 more vote to close them and remove them from the queue.   I kind of know how queues work and my suggestion kind of defeats the purpose of having a queue in first place, but I think one time sort would much help quickly get rid of a great amount of questions that could possibly be closed quickly.  I am not sure how difficult it would be to implement such a sort algorithm so I'll leave it down to the developers.   I think though it would help to decrease the size of the queue quickly.

The Close-Vote queue is large and growing. I searched for definitive information on how that queue is sorted for reviewers, and the nearest I could find is that it is randomized - but that post was some years old.  Would it be possible to sort on order of votes already received? That is, all questions with 4 votes to close are surfaced first (in random order) to reviewers? Questions with 3 votes would come up before ones with 2, etc. In that manner a given question gets out of 'will it close?' limbo faster.   This feature request would, in my opinion, be supportable if the majority of reviewer votes were going to single-vote questions. I cannot (I think) actually find these numbers. If this is the case, the majority of the work is going to an ever-increasing queue, and proportionally fewer votes are being resolved.  Note there are other distributions that could help get in this direction without being a strict ordering, like weighting the chance a given question is surfaced to a reviewer by the number of votes. However, for discussion purposes I thought I'd keep it simple.  Usual apology if this has actually been addressed. Search is sad-making.


I am making a small project.  I have a integer inum, and a array of strings fill.  I am trying to see which part of the array fill is equal to inum.  Here is my code below:          String input = scan.nextLine();         int inum = Integer.parseInt(input);             for(int k = 0; k < 9; k++){                 String cool = "hello";                 cool = "" + inum;                 if(fill[k] == cool){                     fill[k] = "0";   It seems that the computer is not changing fill[k] to 0.  Does anyone know why this is so?  Help is appreciated!

I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?


I have read the following sentece on a lecture notes:  If $G\subset\mathrm{GL}(n,\mathbb{R})$ is a subgroup then its topological closure $\overline{G}$ is a topologically closed subgroup. $\overline{G}$ is obviously topologically closed, and I'm claiming that it's still a subgroup.  Now, I guess the topology is a metric topology (on $\mathrm{GL}(n,\mathbb{R})$ all metrics  are equivalent), but I cannot see how it is true: as it is, it seems a false statement to me. For example, if $G=\mathrm{GL}(n,\mathbb{R})$ then its closure is all the space of $n\times n$ matrixes, which is not a group. Or if I consider the subgroup of diagonal matrix of the form $\lambda\mathrm{Id}_n$, $0\neq\lambda\in\mathbb{R}$, then the zero matrix is in the closure so it is not a group (with respect to the matrix multiplication). I would need the assumption that $\overline{G}\subset\mathrm{GL}(n,\mathbb{R})$ to prove that it is a subgroup. Am I missing something?

I found a proof in the book Fourier Analysis On Number Fields that the closure of any subgroup is a subgroup, using the continuity argument along with the nets. Nevertheless, the following proof seems also plausible, but is it valid?       Statement: If $H$ is a subgroup of a topological group $G$, then so is its closure in $G$.     Denote the closure of $H$ by $H^{closure}$. Let h,h' be two elements in $H^{closure}$, and let $U$ be a neighbourhood of the unity in $G$. Since h and h' lie in $H^{closure}$, there are elements a, a' in $U$ such that   ha$\in H$,   h'a'$\in H$.   Then, as the congugation function is continuous, the left and the right toplogies are the same, and hence there are b, b' $\in U$ such that   hah'a'= bhh'a'= bh"=h"b' $\in H$, where h" is in $H^{closure}H$ $\subseteq H^{closure}$.   As to $H^{closure}H$ $\subseteq H^{closure}$, take two elements e $\in H^{closure}$, f $\in H$, and $v$ in $V$, an arbitrary neighbourhood of unity in $G$. Then there is an element $g$ in $V$ such that   $efv=(eg)f \in HH \in H$.   So $H^{closure}H$ $\subseteq H^{closure}$.   C.Q.F.D.     The proof for the inversion is similar; is there any problem in the argument? Thank a lot here.


From what I read it's not defined as a loss in the list of losing shots, but I'm not sure.

On an 8 ball game, I am left with the 8 ball  close to a pocket and the opponent has one ball blocking the pocket to which I am going to play the 8 ball. If I sink the opponents's ball using the 8 ball and make 8 ball in the same pocket in one shot, who wins the table?


A question was closed As user, I decide to vote for reopening. I click on the Reopen link. An confirm alert appears.  Nominate this question for reopening?                        <Cancel> <OK>  I click OK button. The alert is closed. Now under the question the Reopen (1) appears. I don't refresh the page. I click again on the Reopen link, and the confirm alert from 4. appears again. If I press OK again, the alert is closed. --> Go back to 6.   I guess it's a bug that has to be reported here.  An error message has to appear: "You already voted for reopening this question...".

First of all I know this is a super small bug, but it's still a bug (in my opinion, anyway). When you nominate to re-open a closed question, the link to re-open stays there and if you click it a second time, the same dialog appears as if it is going to let to do it again (but of course doesn't let you).  Normally, I would ignore small things like this. However, I think this kinda makes StackExchange sites appear a little funky. In a way, it (sorta) makes it look bad. I myself have to laugh at this, and I'm sure others have also laughed at it.  The point is, it shouldn't even allow you to press this link again in the first place. Or at least don't show the same dialog asking if you're sure you want to nominate to re-open. Just immediately alert the user that they already nominated.  That is all.


On May 13, 1983 I was granted a Leave to Remain in the UK for an indefinite period visa and since then I have maintained this status by not staying outside the UK for more than two years. During my last visit on July 29, 2018 the border force immigration officer stamped my passport with a Leave to enter for six months and not as a returning resident. I am planning to travel back to the UK next month. Do I need a visa or I can still enter the UK using my indefinite leave to remain status

I travel on a NZ passport and have lived in the UK since 2006. I travelled to Canada in June 2016 to begin a 2 year Canadian working visa but on a trip back to the UK in July I received a 6 month visa stamp in my passport despite having an Indefinite Leave To Remain Visa in my old passport (I haven't got a biometric card yet but plan to apply for one before I return to the UK to live. What should I do about this?


I have this very simple homework problem:   Let $X_1,\ldots,X_n$ be a random sample from the $\operatorname{Bernoulli}(p)$ distribution. Find the Fisher information $I(p)$.    I freely admit that my problem is I don't comprehend what a Fisher Information is.  (Incidentally, is there a difference between Fisher Information and Fisher Information Matrix?)  This is what I have thus far.  Since a Bernoulli Distribution is a Binomial Distribution, the samples are independent and individual.  Since the likelihood function is $\mathbb{L} = \prod_{i=1}^n f(X_i\mid\theta)$ and the log likelihood is $\ell = \log(\mathbb{L}(\theta))$ this yields $I(\theta) = \mathbb{E}\{\mathbb{\ell}\,'(\theta)\mathbb{\ell}\,'(\theta)^T\} = -\mathbb{E}(\mathbb{\ell}\,''(\theta))$.  However, I do not know if I'm on the right path.  I'd appreciate insight.  Thanks, Andy

Let $X_1,...,X_n$ be Bernoulli distributed with unknown parameter $p$.   My objective is to calculate the information contained in the first observation of the sample.  I know that the pdf of $X$ is given by $$f(x\mid p)=p^x(1-p)^{1-x}$$, and my book defines the Fisher information about $p$ as   $$I_X(p)=E_p\left[\left(\frac{d}{dp}\log\left(p^x(1-p)^{1-x}\right)\right)^2\right]$$   After some calculations, I arrive at  $$I_X(p)=E_p\left[\frac{x^2}{p^2}\right]-2E_p\left[\frac{x(1-x)}{p(1-p)}\right]+E_p\left[\frac{(1-x)^2}{(1-p)^2}\right]$$  I know that the Fisher information about $p$ of a Bernoulli RV is $\frac{1}{p(1-p)}$, but I don't know how to get rid of the X-values, since I'm calculating an expectation with respect to $p$, not $X$. Any clues?


This feels like it should be obvious, but I'm failing to figure it out.  I own a Sony a5100 -- an APS-C camera with a 1.6 crop factor.  I have long owned the SEL50F18, a 50mm f/1.8 lens designed for APS-C.  I wanted a slightly-more-telephoto lens to add to my kit, and after having tons of fun reading reviews, I decided to buy an old manual Minolta MC ROKKOR-PG 50mm f/1.4 and an adapter to E-mount.  It was cheap (about $75 for the set), and the idea of a fully-manual lens with some "character" sounded like fun.  Since the Minolta MC was for a 35mm film SLR, I anticipated the 1.6 crop factor making this lens have the same angle-of-view as an 80mm lens designed for APS-C (since the 50mm lens should produce an image circle much larger than my APS-C sensor)  The adapter is a cheap "Fotasy MD-NEX" adapter which has no optical elements.  So, I was very surprised when my gear arrived today and the new ROKKOR-PG produces images that have the same angle of view (or, at least, close enough that I can't tell the difference)  Where is the hole in my logic?  Why do these two lenses produce images with similar angle-of-view?

I have a Canon 7D, which has a crop factor of 1.6x.  When using a Canon EF-S lens I get the focal length stated on the lens, when using a Canon EF lens I get the focal length times 1.6 when used on the APS-C body. At least that's what I thought.  I just compared two lenses:   Canon EF-S 15-85mm f3.5-5.6 Canon EF 70-200mm f4   .  The top photo is shot with the 15-85, the bottom photo with the 70-200 - both lenses are set to 70mm. Now why do they look the same?  I thought I would get 112-320mm (70mm*1.6 crop factor). What did I misunderstand about the crop factor calculation? Lightroom also displays the photos as having "70mm" and not 112mm.


Is it possible to retrieve the index into a text area that the cursor is at using the keydown event?

How do you get the caret position in a <textarea> using JavaScript?  For example: This is| a text  This should return 7.  How would you get it to return the strings surrounding the cursor / selection?  E.g.: 'This is', '', ' a text'.  If the word “is” is highlighted, then it would return 'This ', 'is', ' a text'.


So whenever I am in hotels (or other public networks) after I connect to the hotel network a browser window opens with a logon page or customer agreement.  How does Windows know to open a webpage when connecting to the network?

In Windows 7, the notification area networking icon will show an error indicator if there is no internet access , and the error icon goes away once there is a successful connection to the internet . Sometimes, if the WiFi connection requires an in-browser authentication step, like on many guest networks in hotels or universities, then the following pop-up bubble appears, saying as much:    How does Windows know whether or not it has a successful internet connection? Presumably it is checking some online Microsoft service to see whether it has a successful connection, gets redirected to some other page, or doesn't get any response at all, but I haven't seen anywhere that this process or the services used are documented. Can anybody explain how this works? I would prefer answers that refer to facts, rather than just guessing, but if you have a really good guess, then go for it.     This question was a .   Read the May 16th, 2011  for more details or  Question of the Week.