I see some posts about asking for product recommendations, which is not allowed in StackExchange family. I understand. QA for recommendations, or shopping questions is not feasible. But for getting a list of names of software applications fulfilling some requirements should be ok, and very useful.  This need showed up when I was going through a document with 30 steps, scrolling up and down, and thought there should be a tool that converts text to a wizard. But searching for such a tool in google returns irrelevant results (maybe my keywords are bad).  I love the way Stack Overflow and the other Stack Exchange sites answer questions. It would be really helpful to ask 'Is there a tool that does X' and get a list of products.  What do you think? If you agree, how can we get such a site?

I have a list of requirements for a program, but I don't know what program meets these criteria. That's about general-purpose software, for example, not a programming IDE or statistical workbench, questions about which would certainly go to respective sites.  Is this question appropriate on Stack Overflow? Where should I ask about it? On Super User or elsewhere?


Here is the situation. I left my pc at home doing an rsync from a 2TB hard drive to another 2TB hard drive (it's going to take a while since they are both USB 2.0). I am now at work and I have ssh-ed into my home pc. If I do ps aux | grep rsync I can see the following:  1000  7214 18.8  0.1  30636  1368 pts/0 S+   00:52 134:00 rsync -vr /media/master /media/slave   However I want to see exactly what rsync is doing. When I was at home, the standard output was shown in my terminal and the verbose mode of rsync showed which files were currently being copied. Is there any way to read stdout for another pts?  $ ps -t pts/0 7214 pts/0    02:14:42 rsync   I did a little bit of googling and it seems that /proc/pid/fd may hold the answer but I'm not sure about this...  P.S. I have sudo privileges of course.

I have left a script running on a remote machine from when I was locally working at it. I can connect over SSH to the machine as the same user and see the script running in ps.   $ ps aux | grep ipcheck myuser  18386  0.0  0.0  18460  3476 pts/0    S+   Dec14   1:11 /bin/bash ./ipchecker.sh   It is simply outputting to stdout on a local session (I ran ./ipchecker.sh form a local terminal window, no redirection, no use of screen etc).  Is there anyway from an SSH session I can view the output of this running command (without stopping it)?  So far the best I have found is to use strace -p 18386 but I get hordes of text flying up the screen, its far too detailed. I can stop strace and then sift through the output and find the text bring printed to stdout but its very long and confusing, and obviously whilst it's stopped I might miss something. I would like to find a way to see the script output live as if I was working locally.  Can anyone improve on this? The obvious answer is to restart the script with redirection or in a screen session etc, this isn't a mission critical script so I could do that. Rather though, I see this as a fun learning exercise.


I have an app with a menu, my menu has the option to logout from the app  my idea is to create a file to keep all my reusable function so icreate a Support file,  on my support file I have the logout function and I'm trying to call the logout from my mainactivity class,  but I keep getting this error:     java.lang.NullPointerException: Attempt to invoke virtual method   'java.lang.String android.content.Context.getPackageName()' on a null   object reference   I was testing the funciton my only doing "Log.e...." i have able to log the text   public boolean onNavigationItemSelected(MenuItem item) {      int id = item.getItemId();      if (id == R.id.home) {         Toast.makeText(this, "Home", Toast.LENGTH_LONG).show();     } else if (id == R.id.nav_logout) {          com.myapp.myapp.MAIN.Support.Support support = new com.myapp.myapp.MAIN.Support.Support();         support.logout();      }      DrawerLayout drawer = findViewById(R.id.drawer_layout);     drawer.closeDrawer(GravityCompat.START);     return true; }  public class Support extends Activity {       public void logout() {         Intent intent = new Intent(context, com.myapp.myapp.MAIN.Activities.LoginActivity.class);         intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);         intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);         intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);          startActivity(intent);         Log.e(TAG, "Aquii");     } }

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 tried to compute the power of 2^2^2^2 on google calculator and my casio calculator but both are giving different results. same is true for 3^3^3. Please explain me the difference between two expressions.

Does $x^{y^z}$ equal $x^{(y^z)}$? If so, why?   Why not simply apply the order of the operation from left to right? Meaning $x^{y^z}$ equals $(x^y)^z$?  I always get confused with this and I don't understand the underlying rule. Any help would be appreciated!


I want to write a 32 bit reg to 22 bit reg while conserving the number and its sign.  reg [31:0] test_dat0; //test_dat0 <= -4 (binaire) reg [22:0] test_dat1; test_dat1 <= test_dat0 ; ??? //what is the value of test_dat1 here   is it right ?  thank you

As in these two cases:  wire [3:0] A, B; wire [4:0] C, D;  assign A = C;  // larger width to smaller width assign D = B;  // smaller width to larger width   What should A and D look like in terms of C and B respectively?


I've just joined a project which is developed for internal use for over 10 years now. There are no unit tests nor any other manual/automated tests designed. I'm going to be the only tester. What should I start with when it comes to testing in general? There is no detailed specification or documentation. I was thinking of going through the past bugs/tickets/stories developed and prepare test cases based on that. Also to start preparing test cases for regression tests for key functionalities. In the future, I will consider automating the regression suite with Selenium most likely (especially that my exp is very little in this topic). The project is developed in .net and .net core technologies. Please share your thoughts and experience. Thanks!

I'm a Java developer by trade. I was 'brought-up' in what you could call best practices. Then I took my current job. I had a choice between the Java/SOA team, and the ERP team. I was told that joining the ERP team would give me the best insight into how the business operates (not in terms of technology, but in terms of business.) So I went with ERP.  I found a system with over 4 million lines of "Progress 4GL" code (since renamed to Openedge ABL, because "4GLs sound bad") code, spread out around about 11000 files. The best part is, no file exists more than one folder down. So you have about 50 folders, each with 300-400 files a piece in them. Luckily, many of the files haven't been touched in over 7 years, and many of them are deprecated (but we don't delete them from version control "just in case." Don't even get me started on that one.) So there's really only about 1.5 million lines of code we'd actually have to test. "Only."  I could go on and on about the poor practices of the system. The bottom line was for years, developers had no option to say no. It was "gimme gimme gimme," combined with a lot of contractors moving in and out. Now, they want to clean up their act.  One of the first things I suggested was testing. They said, basically "we've been wanting to do testing for years, but we don't really know where to start." The business logic and database access are baked into the UI. (I'd say GUI, but it's not graphical, it's on a mainframe. Even the order-entry people telnet in.)  So this is pretty much a worst case scenario. Millions of lines of code. Over a billion dollars in annual sales running through the system, so it's not going to get a re-write (obviously "it works as it is.") No object orientation. No formal or automated tests. Our testers are also the ones who write the specs (which biases them toward "pushing the project through.")  I'm getting pretty desperate. I'm even willing to write whatever testing frameworks (there isn't much for Openedge in open source frameworks) we need on my spare time. I'm convinced it will pay for itself quite quickly. Where can we start? Has anyone here come across a similar project (even if smaller in scale) and if so, how did you cope with and overcome this?  Update: I've had a chat with my manager, and I have approval to draw up a spec/timeline for creating a test harness. At first, I heard this: "What we really need to do is write some tests." to which I responded "Having tests won't really help us if we don't have a way to run them. I've been looking into ProUnit (the old name for OEUnit) and think it will work for us." "We should write some tests using it." It took about 10 minutes of repeating this for him to realize it was not as simple as downloading the library and "using it." But, approval to write a spec to create a test harness is a start! Thanks guys for all your input!


I accidentally run git checkout . and lost the changes I made on my local repo.   I remember that once I had those changes stashed but I used git stash pop to retrieve them (sadly, I didn't know about git stash apply at the time), and now I can not find these changes on my stash.  I searched on SO but most of the answers were for git stash apply, or told me to retrieve the SHA-1 outputted after the git stash pop, but I don't have that information.  Is there any way to recover my changes?

I frequently use git stash and git stash pop to save and restore changes in my working tree. Yesterday I had some changes in my working tree that I had stashed and popped, and then I made more changes to my working tree. I'd like to go back and review yesterday's stashed changes, but git stash pop appears to remove all references to the associated commit.  I know that if I use git stash then .git/refs/stash contains the reference of the commit used to create the stash. And .git/logs/refs/stash contains the whole stash. But those references are gone after git stash pop. I know that the commit is still in my repository somewhere, but I don't know what it was.  Is there an easy way to recover yesterday's stash commit reference?  Note that this isn't critical for me today because I have daily backups and can go back to yesterday's working tree to get my changes. I'm asking because there must be an easier way!


In our area, we have  (cable) which offers 1 Gbit/s down, and 30 Mbit/s up, while  (fiber) offers 1 Gbit/s up and down.   Why does copper only 'allow' fast speeds for download, but not upload? Is this a limitation companies put in place on purpose?

I recently switched from an ADSL to a fiber connection and was surprised to see that the bandwidth is asymmetric (1 Gbps down / 250 Mbps up).  While this is understandable in ADSL, I do not understand why fiber at home is asymmetric as well? It is not a limitation of the technology (I have symmetric fiber at the office, and always had)


When studying the general angular momentum $\textbf{J}$, which is defined as a vector operator with its components being Hermitian operators satisfying the commutation relations \begin{align*} \textbf{J} \times \textbf{J} = i\hbar \textbf{J} , \end{align*} and the simultaneous eigenvectors of $\textbf{J}^2$ and an abitrary component $J_z$, my book stated that the eigenvalues $j$ and $m$ are either integer (including zero) or half-odd-integer values. They came to this conclusion by using the raising and lowering operators which are defined as \begin{align*} J_{\pm} = J_x \pm iJ_y. \end{align*} More specifically, because of the inequality \begin{align*} j(j+1) \geq m^2 \end{align*} there must be an upper and lower bound $m_T , m_B$ which differ from each other an integer amount $n$. However, what ensures that these eigenvalues are the only possible values? How can it not be that the spectrum of eigenvalues is continuous? Say for example we forget about the raising and lowering operators and just postulate that there exists a simultaneous eigenvector of both $\textbf{J}^2$ and $J_z$ with $j = 2.3$ and $m = 2.3$. Is there a way to contradict this assumption? I have already found an answer using the representation theory of Lie algebras, but since my mathematical background is limited, I would like to have a simpler explanation. If this is the only formal explanation, then I would like to know that and move on :). The book I use for studying QM is Bransden & Joachain (chapter 6.5).

Why is it that unlike other quantum properties such as momentum and velocity, which usually are given through (probabilistic) continuous values, spin has a (probabilistic) discrete spectrum?


$$a_k = \left\{      \begin{array}{lr}        2a_{k-1} - a_{k-2} &: if \space k > 2 \\        3 & :if\space k =2 \\        2 & :if \space k =1      \end{array}    \right.$$  It's easy to see that the nth term is n+1 based on the pattern but how do I actually show it? Is there a general way to solve these recurrence problems?  The only way I can think of is $a_k - a_{k-1}=a_{k-1}-a_{k-2}$ implies arithmetic progression, so based on that n+1

I know how to solve "simple" recurrence relations. For instance, say you have:  $$c_0 = 20$$ $$c_1 = 30$$ $$c_n = 3 c_{n-1} - 2 c_{n-2}$$  We can write the characteristic equation as:  $$3x^{n-1} - 2x^{n-2} = x^n$$  Solving this with $n=2$, we get $x = 1$ or $x = 2$. This lets us write the relation $c_n = \alpha_1 1^n + \alpha_2 2^n$, and we can solve for $\alpha_1$ and $\alpha_2$ with the initial states $c_0$ and $c_1$.  However, this depends on the fact that $3x^{n-1} - 2x^{n-2} = x^n$ has two roots.  Now, I'm stuck on another problem where the characteristic equation has fewer roots than terms.  Say I have this recurrence relation instead:  $$a_0 = 0$$ $$a_1 = 2$$ $$a_2 = −1$$ $$a_n = 9a_{n-1} - 15a_{n-2} - 25a_{n-3}$$  The characteristic equation would be:  $$9x^{n-1} - 15x^{n-2} - 25x^{n-3} = x^n$$  However, solving with $n=3$, we only get two roots: $x=-1$ or $x=5$. There are not enough roots to write a relation in the form of $a_n = \alpha_1 r_1^n + \alpha_2r_2^n + \alpha_3r_3^n$. How do I proceed?


Why was  answer turned community wiki? Only two users have revised it. I  saw  that the idea behind CW is that the OP is not the sole owner of the post but many users own it. Is there a lower limit on the number of users editing the post which if crossed then the question turns CW?

Some questions and answers are marked Community Wiki and are owned by a community wiki user:  (In fact, this very question is one of them)  Why have Community Wiki posts? How do Community Wiki posts work? How does a post become a Community Wiki post? How can the Community Wiki status be removed from a post? How can I find Community Wiki posts?


I have been searching already but I have no idea how those e and j are called and therefore not found useful information. I am searching for numbers with chars for specification or as operators.  Like this exponetial e notaion:  1e3 = 1 * 10^(3) = 1000 xen = x * 10^(n)            # where x and n are numbers   or imaginary numbers with j:  1 + 3j   The benefit I am hoping for is to be able to write Ppm(2) (instance of Ppm class) conveniently as 2ppm (where "ppm" is "parts per million" of a frequency in NMR). This can't be thoroughly done with the exponential notation 2e-6 because ppm is referenced to a frequency. Hence it should be distinguished from ordinary numbers.

Can you add new statements (like print, raise, with) to Python's syntax?  Say, to allow..  mystatement "Something"   Or,  new_if True:     print "example"   Not so much if you should, but rather if it's possible (short of modifying the python interpreters code)


I have successfully installed GUI/Python/VMware View Agent on one Ubuntu VM. But the second day after I powered it on, Ctrl+Alt+F1 was not working any more.  Is there any possibility to back to Command line?     Update: Finally I figured out Ctrl+Alt+F1 is not functional because I installed VMware View Agent. But so far I don't have any solution.

How to switch between virtual console and GUI in Ubuntu? I wanted to see what key functions would allow me to switch between the two.


I would like to study basic electricity and magnetism with a book with a good mathematical language (e.g. to calculate the thing with gauss law the book explain the importance of parametrization, coordinate change inside integral and so on...)

What books are recommended for an advanced undergraduate course in electrodynamics?


As part of a txt file with instructions on how to run, I use a folder name as a parameter as shown below. However, LINUX does not recognize it. What could I be doing wrong?  foldername = "SOPHIE_TRANS" matlab -nodesktop -nosplash -r "CellSort($foldername);quit"

What is the difference between below variables assignments?   var=23 var =23 var= 23 var = 23   Is there any difference in space around the assignment operator?


Does anyone know the name of this rotated, filled in, black square symbol?

I know what my symbol or character looks like, but I don't know what the command is or which math alphabet it came from. How do I go about finding this out?


I had my Windows 10 installation, but then I decided to dual boot with Linux. I did it, and I noticed, that I have -2h on the clock on my Linux. I've searched the internet for the answer (the time zone was good). I don't really remember what I did, but I do remember setting ntp to true and hwlclock systohc --rtc, or something like this.  Now the time on my Linux is good, but the time on Windows is 2 hours late. I have to manually go to Adjust date/time -> Sync now to make it right.  I know this is messy, but I can't quite remember what exactly I did on Linux. Now the situation is like this. Is there a way to fix it? Or maybe force Windows to automatically sync, or something?

Ever since I started using Linux in dualboot with Windows I noticed that when I rebooted the machine, the time on the other OS was wrong, e.g. it was 12:00 on Linux, then I rebooted and on Windows it was 18:00, and when I checked the BIOS, the RTC was set to 18:00. Since my timezone is -06:00 CST I assume Linux just sets the RTC’s time to UTC and re-calculates the time based on the timezone, whereas Windows just sets the RTC to the local time. Both use the same NTP server to sync the time.  The question is, which one is doing the right thing? On which one should I set the timezone setting to UTC in order to have the right time on both?


On first look this can seem weird. But I can explain what I am looking for.  We all know from elementary maths that $(-\times-)=+$.   Now, lets say there are 3 cows and I say they will become doubled after one year so $3*2=6$.  And lets say I have $-3$ cows(which is not possible, because I can show $3$ cows but not $-3$) and if I multiply it by $-2$, I get $-3\times -2=6$. How is it possible?, nothing multiplied by nothing equals something?  Some said the reason belongs to philosophy, if yes, what's the idea behind it?

Someone recently asked me why a negative $\times$ a negative is positive, and why a negative $\times$ a positive is negative, etc.  I went ahead and gave them a proof by contradiction like so:  Assume $(-x) \cdot (-y) = -xy$  Then divide both sides by $(-x)$ and you get $(-y) = y$  Since we have a contradiction, then our first assumption must be incorrect.  I'm guessing I did something wrong here. Since the conclusion of $(-x) \cdot (-y) = (xy)$ is hard to derive from what I wrote.  Is there a better way to explain this?  Is my proof incorrect?  Also, what would be an intuitive way to explain the negation concept, if there is one?


Often I will have downvoted an answer shortly after it is posted, or commented on an answer suggesting some improvement or addition, and want to follow up later and see if my input has been acted upon, so that I can retract my downvote or take further action as appropriate. (Aside: do others do this, or am I a sad obsessive?)  Currently, I can favorite the question that the answer was on, both as a reminder to myself that I'm interested in it and in order to get notified when something changes, and I do so, but it's not an ideal solution when I'm only interested in a single answer on the page, for two reasons:   It generates noise that I'm not interested in on my favorites tab, as I get notified whenever anything on the question or the other answers there gets modified, not just stuff on the answer I'm interested in. When I do come to have a look at the question, I've frequently forgotten which answer I'm interested in or why the heck I ever favorited this question in the first place.   (I realise that , but since it was a long time ago, my particular use case for the request was not discussed, and I think notifications on favorites weren't even implemented yet back then, I figured it was reasonable to start another thread for this request. Feel free to downvote or close if you think my doing so wasn't appropriate.)  The ability to favorite answers would solve this use case for me. Is there any chance we could get this feature?

Lots of questions are very generic, "share an experience" kinds of questions. In these cases, I am quite often interested in specific answers that may not have gotten that many upvotes. These questions also tend to elicit lots of responses, so going back to find the answers I'm interested in somewhere in the middle of a sea of responses is a pain. Is there a way to favorite or bookmark these answers?


I want to replace content of long Strings in postgres column.  The match pattern is "{Begin}{anything}{mid}{anything}{end}", and the match is non-greedy version.  Begin, mid, end is fixed content while anything can include character, number, space, newline etc.  With common regex we can use ([\s\S]*?) but it doesn't work well in Postgres. How can I do with this.  Example: I have a DB column name "descriptor", I want to match content   "<function type="class"> {anything} <arg name="class.name">com.ehi.jira.plugin.workflow {anything} </function>",   and it should match the shortest content.With common regex I will use   "<function type="class">([\s\S]*?)<arg name="class.name">com.ehi.jira.plugin.workflow([\s\S]*?)</function>".   But it doesn't work in postgresql.

For example, this regex  (.*)<FooBar>   will match:  abcde<FooBar>   But how do I get it to match across multiple lines?  abcde fghij<FooBar>


The problem I am face with is that I have all my data as shapefiles but my organization works with only 1 ArcGIS license. Migrating to QGIS to prominent amount of work, I need to convert my ArcGIS .style file to the .sld format of QGIS, to ensure uniformity of data capture and maps.   I am working with Python for this, Could anyone give me any suggestions?

I have downloaded a dataset from a government organisation. it comes with a .style file.  I use QGIS 1.8 on windows 7.    Is there a way to use the .style file as a qml or sld? I have tried simply changing the extension but to no avail.


Probably is a stupid question. I look for it on Google but honestly I don't know how search it. Look at this example:   .container {   border: 5px solid black; }  .text {   border: 1px solid red;   margin: 5px; }

text1

Long text long text long text

example

    Why the text containers are long as the parent container and not as long as the inside text? And how can I do to make the text container long as the text?

I have a layout similar to:  <div>     <table>     </table> </div>   I would like for the div to only expand to as wide as my table becomes.


When I select "Keyboard layout" it generate buttons using js - but click event not works with dynamic generated buttons. I think, it is because when document ready, element ".prices-tier" not exist. It generates, only when i select layout.    Part of my code:      require(['jquery'], function(){     jQuery(document).ready(function(){         const currencySymbol = jQuery('.price').text()[0];         var standartPrice = Number(jQuery('.price-wrapper').attr('data-price-amount'));            jQuery('.prices-tier').on('click','.btn', function () {             var quantity = Number(jQuery(this).attr("data-qty"));             var price = jQuery(this).attr("data-amount");             jQuery('.qty-default').val(quantity);             jQuery('#product-price-'+"<?php echo $_product->getId();?>"+' .price').html(currencySymbol+price);             // jQuery('.product-info-main>div>.price-box>.price-container>.price-wrapper>.price').html(currencySymbol+price);             jQuery('.qty-default').trigger('input');         }         );   Generated html elements:  <div class="prices-tier items w-75 btn-group">          <button type="button" class="btn btn-light border border-bottom-0 border-top-0 bg-primary" data-qty="25" data-amount="27.21" onclick="">          4%</button>          <button type="button" class="btn btn-light border border-bottom-0 border-top-0 bg-primary" data-qty="50" data-amount="26.5" onclick="">          6%</button> </div>

I have a bit of code where I am looping through all the select boxes on a page and binding a .hover event to them to do a bit of twiddling with their width on mouse on/off.  This happens on page ready and works just fine.  The problem I have is that any select boxes I add via Ajax or DOM after the initial loop won't have the event bound.  I have found this plugin (), but before I add another 5k to my pages with a plugin, I want to see if anyone knows a way to do this, either with jQuery directly or by another option.


I am getting confused with this little word, and I would be very grateful to know more: I am looking on many , and they all include and in their list of coordinating conjunctions. So that is clear. I cannot find it in the list of subordinating conjunctions, but I just want to make sure Can "and" ever be a subordinating conjunction? In a sentence like  Let us wait, and she will do what we want.  am I right that "and" is a coordinating conjunction uniting two independent clauses? Edit 1: I underline that my query concerns the particular use of the conjunction "and" in a sentence with conditional meaning, and not coordinating and subordinating conjunctions in general. Edit 2: I had no doubt that "and" can connect any kind of phrases or  clauses (be they subordinate or independent), as long as they are of the same kind. My confusion began when a native speaker claimed that "and" can link an independent clause with a subordinate one. I would appreciate any insight on this.

While it is easy enough to identify coordinating and subordinating conjunctions by memorizing lists of them, the actual distinction seems arbitrary.  Coordinating conjunctions are said to join (among other sentence elements) two independent clauses, while subordinating conjunctions are said to join a subordinate clause to an independent clause.  The problem is that it appears to be the very presence of a subordinating conjunction which makes an otherwise-independent clause subordinate.  For example, in the sentence...     Stock prices would have plummeted, unless the company issued a public   apology.   ...the second clause is only subordinate by virtue of including the word "unless."  "The company issued a public apology" expresses a complete thought, but "unless the company issued a public apology" does not.  So the presence of the word "unless" explains why the second clause is subordinate, which explains why "unless" is a subordinating conjunction.  However, in the sentence...     Stock prices would have plummeted, but the company issued a public   apology.   ...the same analysis is not applied.  Rather, the word "but" is considered to stand between the two clauses, belonging to neither.  This grants independent status to the second clause, "the company issued a public apology," whereas if the word "but" were to be included, it would be a subordinate clause, and therefore "but" would be a subordinating conjunction.  A sort of explanatory circularity is apparent, and it's not at all clear to me why "unless" and "but" should be treated differently in these examples.  What is so special about the FANBOYS conjunctions that they are said to stand outside of independent clauses, while the rest are said to be part of otherwise-independent clauses, making them subordinate?


In Ryder, when trying to restore the local $U(1)$ gauge symmetry of the complex scalar field $\phi=\phi_1+i\phi_2$, the final Lagrangian consists of the following four parts: $$L_0=(\partial_{\mu}\phi)(\partial^{\mu}\phi^*)-m^2\phi^*\phi$$ which is the free particle Lagrangian, $$L_1=-eJ^{\mu}A_{\mu}$$ which is where the $A_{\mu}$ is introduced, $$L_2=e^2A_{\mu}A^{\mu}\phi^*\phi$$ and $$L_3=-\frac{1}{4}F^{\mu\nu}F_{\mu\nu}$$ with $F_{\mu\nu}=\partial_{\mu}A_{\nu}-\partial_{\nu}A_{\mu}$, which is gauge invariant. On top of $L_0$, the additional $L_1$ and $L_2$ seems to be quite natural. However, for the $L_3$ part, it doesn't seem to be necessary to me, while Ryder's argument is that "the field $A_{\mu}$ must presumably contribute by itself to the Lagrangian". If we now look back, we know that the $L_3$ term actually gives us the Maxwell's equations. but I'm still not convinced by Ryder's argument. So the question is how do we know that $A_{\mu}$ must contribute to the Lagrangian?

So I know that for an electromagnetic field in a vacuum the Lagrangian is $$\mathcal L=-\frac 1 4 F^{\mu\nu} F_{\mu\nu},$$ the standard model tells me this. What I want to know is if there is an elementary argument (based on symmetry perhaps) as to why it has this form. I have done some searching/reading on this, but have only ever found authors jumping straight to the expression and sometimes saying something to the effect that it is the "simplest possible".


I am creating my own widget. I need to use custom css and js files. I have used wp_register_style`wp_enqueue_styleandwp_register_script\wp_enqueue_script` functions in order to register custom styles and scripts.     I implemented this in following way.  function __construct() {         // parent constructor         add_action( 'wp_enqueue_scripts',array( $this,'init_widget')); }  public function init_widget() {     wp_register_style( 'accordion-category-style', plugins_url('accordion-category-style.css', __FILE__) );     wp_enqueue_style( 'accordion-category-style' );     // Register the script like this for a plugin:     wp_enqueue_script('jquery');     wp_register_script( 'accordion-category-script', plugins_url( 'accordion-categories.js', __FILE__ ) );     wp_enqueue_script( 'accordion-category-script' ); }   And this works perfectly, but one problem that these files are included on each page of the site.   But I only need to include on page where my widget is visible. Is it possible to achieve such behavior ?   SOLUTION   I tried to use solution suggested by @jdm2112 , but I used not the accepted answer from his link but just checking inside widget method like this and this works   public function widget( $args, $instance ) {     if ( is_active_widget(false, false, $this->id_base,true) ) {         $this->init_widget();     }    One issue is this adds scripts in the middle of html page not at the top.

I needed a way to filter a page/posts content before it was loaded so I could add scripts to the header if a specific shortcode was present. After much searching I came across this on    function has_my_shortcode($posts) {     if ( empty($posts) )         return $posts;      $found = false;      foreach ($posts as $post) {         if ( stripos($post->post_content, '[my_shortcode') )             $found = true;             break;         }      if ($found){         $urljs = get_bloginfo( 'template_directory' ).IMP_JS;      wp_register_script('my_script', $urljs.'myscript.js' );      wp_print_scripts('my_script'); }     return $posts; } add_action('the_posts', 'has_my_shortcode');   which is absolutely brilliant and did exactly what I needed.   Now I need to extend it a bit further and do the same for sidebars. It can be by a particular widget type, shortcode, code snippet or anything else that would work to identify when the script needs to be loaded.  The problem is I can't figure out how to access the sidebars content before the sidebar is loaded (the theme in question will have several sidebars)


Which vehicle is more appropriate for the "Mountain" stage of ?

In Hill Climb Racing we have several vehicles and several stages.  Different vehicles have different performances on the same stage, and I'd like to know what are the best combinations to maximize distance in each stage.    Also, what is the best combination of a vehicle and a stage to get lots of coins?


I need to setup a Zentyal Server on my Ubunut for School, but during this process I encountered some errors:  root@nasr-kmu2:~# sudo apt install zentyal 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:  zentyal : Depends: zentyal-core but it is not going to be installed            Depends: zentyal-software but it is not going to be installed E: Unable to correct problems, you have held broken packages.   Due to some recommendations on the Internet I tried the following, but nothing helped.  root@nasr-kmu2:~# sudo apt-get install -f Reading package lists... Done Building dependency tree        Reading state information... Done 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. root@nasr-kmu2:~#    Any Ideas ?

After upgrading from 10.04 to 12.04 I am trying to install different packages.  For instance ia32-libs and skype (4.0).  When trying to install these, I am getting the 'Unable to correct problems, you have held broken packages' error message.   Output of commands:  sudo apt-get install -f Reading package lists... Done Building dependency tree        Reading state information... Done 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.   After running this:  sudo dpkg --configure -a foo@foo:~$ sudo apt-get install -f Reading package lists... Done Building dependency tree        Reading state information... Done 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.


After unlocking my computer, I noticed that all of my usual indicator icons went missing this afternoon. I'm missing icons for Slack, Keybase, Chrome, Nextcloud Client, Dropbox, Deluge, Flameshot, and Skype. Before I noticed this, I also noticed that my side-bar (with icons for my open apps and favorited ones) was visible on my lock-screen. I couldn't get a screenshot of that, though, as the Print Screen was (rightfully) still disabled on lock screen and is probably not related.    I saw , but his issue was that Unity was messing him up. This particular laptop has never had anything below 18.04 installed on it. It came with Windows 10 but I promptly replaced it with Ubuntu 18.04 as soon as I got it. As such, Unity has never been installed.

After upgrading to 18.10 I am experiencing very strange behaviour of gnome extensions. After my laptop goes into hibernation they all switch off and enabling them back on  doesn't help: nothing changes and when I refresh the page they are disabled again.   The only way to turn them back on is to reinstall them.


I have location points collected from a garmin device stored in an excel sheet in Degree Minutes format --- W00208.172,N1046.977.  I am looking for an Excel formula to convert either to Decimal Degrees or Degrees Minutes seconds Format ?

I am looking for either an online tool or one that I can download to convert DD to DMS.  For example, I want to convert from:  41.590833, -93.620833 to 41° 35′ 27″ N, 93° 37′ 15″ W ...  Those are the coordinates, according to , for Des Moines.


Basically, I'm trying to create a quiz app (well, not really a quiz, basically clicking one option leads to another question set exactly for that option.) And don't mind the stupid questions and answers I've put in there - those are placeholders.   The error that I've gotten is that the pos variable seems to reset everytime I call renderQuestions().  <!DOCTYPE html>       <meta charset="UTF-8">     <title>yo</title>

           Here is what it looks like when I debug it in the console:   It seems like after clicking the radio button, it succesfully sets the pos to 1, but then immediately resets it to 0. Why is that?

What is the scope of variables in javascript? Do they have the same scope inside as opposed to outside a function? Or does it even matter? Also, where are the variables stored if they are defined globally?


I have mirrored a directory from a server with a large number of sub directories, each of which contain a .txz package and the usual .txt and descriptor files. What I would like to do is the following:  Find/locate all the .txz files within all the sub directories, then move them all to a specific folder; using regular expressions. What would the regular expression to use be, in bash on slackware linux? Thanks

I have a folder with lots of images,I want to move all images which  filename contains "cover" and size is bigger than 100K to /root/img. Below command can move all the files that filename contains "cover" but without size condition.My questions is how to combine with condition that image's size is bigger than 100K.thank you!  find . -name '*cover*' -exec mv '{}' /root/img  \;


My aim is to display the person name and all the reason for his absences(concated and displaying in a string).  I am using the following query to display the EmployeeName, ReasonForAbsence. I am having problem with concatenating and Displaying all record specific column called 'AbsenceReason'. The error is  Incorrect Syntax near ='. More info about error- its happening for displaying absence reason part.  SELECT               --Displaying Name,                            EMP.NAME,                --Displaying Absence Reason              (                SELECT                     @AbsenceReasons= @AbsenceReasons + ';' + REASONTEXT                 FROM                      ABSENCE                  WHERE ID=EMP.ID                )   FROM            (              SELECT                     *                FROM                        Employees             ) EMP   What have I missed?  Thank you

I'm trying to migrate a MySQL-based app over to Microsoft SQL Server 2005 (not by choice, but that's life).  In the original app, we used almost entirely ANSI-SQL compliant statements, with one significant exception -- we used MySQL's group_concat function fairly frequently.  group_concat, by the way, does this: given a table of, say, employee names and projects...  SELECT empName, projID FROM project_members;   returns:  ANDY   |  A100 ANDY   |  B391 ANDY   |  X010 TOM    |  A100 TOM    |  A510   ... and here's what you get with group_concat:  SELECT      empName, group_concat(projID SEPARATOR ' / ')  FROM      project_members  GROUP BY      empName;   returns:  ANDY   |  A100 / B391 / X010 TOM    |  A100 / A510   So what I'd like to know is: Is it possible to write, say, a user-defined function in SQL Server which emulates the functionality of group_concat?   I have almost no experience using UDFs, stored procedures, or anything like that, just straight-up SQL, so please err on the side of too much explanation :)


When I'm running several instances of the same app (might be Chrome separate windows, or several IntelliJ projects) in fullscreen mode, I can't navigate to concrete app using ⌘-Tab, it will just show one icon of the app but there are several running in the background.  Also there is no application specific shortcut to do so.    Is there a way to make ⌘-Tab show instances rather than global app icon?

Is there a keyboard shortcut in Lion for navigating through my open full screen Xcode projects? ⌘~ is not working.


Everyone knows Google linked everything in one account. YouTube, Gmail, etc.  I'm trying to recover my YouTube account but it send me to my Google account so I don't remember that password. I go to the options that help me get it but the options there are truly useless as I do not remember when was the last time I used it because I only use YouTube (never my Google account) neither when I created it because I had that YouTube account for a long time and suddenly there were some emails about some merging between this two accounts.  Can't Google just send me a recovery password/code to the my email? I will be the only one supposed to see it.

I have forgotten the password or username for my Google account, or I'm unable to access my account for other reasons.  How can I recover my account?  (This Q&A is meant as a general description for all Google and Gmail username/password questions. See: )


I am planning to travel to UK for tourism with two other family members. Do I need to submit separate applications or a single application with details of all the family members?

My wife and I are both applying for a UK Standard Visitor visa.  Do we need to fill the visa application form at visa4uk separately?  That would mean we will have to go for biometric appointments separately.  Is that how it works?


I created a .command file that runs a certain command java -jar myApp.jar in the Terminal, however it doesn't work because it first needs to cd into a certain directory. Is there a way to make the .command file automatically go to the address where the .command file currently is, and execute the command from there? I can't just add the cd line into the script because I need to distribute this and it needs to work no matter where on the computer it is.

How do I get the path of the directory in which a  script is located, inside that script? I want to use a Bash script as a launcher for another application. I want to change the working directory to the one where the Bash script is located, so I can operate on the files in that directory, like so: $ ./application


I have set up an Amazon RDS Mysql instance and it is successful. I am trying to create some tables but I am getting this error:  #1290 - The MySQL server is running with the --read-only option so it cannot execute this statement   I have tried to set global to read-only = 0 but my user does not have privileges. I have tried googling for a solution to no avail. (I am pretty new to RDS)   Update I do not have a create read replica option on my actions

I have a database on an RDS Instance (master) that needs to be synchronized to another RDS instance (slave). I created a read-replica for the first one, but that is created as read_only so I cannot do any operations on it.  Basically, I'll need to create a few other databases on the slave instance as well so that needs to be non-read-only. I'll also need to setup sync to happen once daily.  I am using MySQL 5.6+.


I am facing one issue dimension = ['category','amount']  // Just imaging I am getting an array like this frim request for _, obj in enumerate(qs1):     kwargs.update({obj[dimensions[1]]: Count(dimensions[1],                      filter=Q(dimensions[1]=obj[dimensions[1]]))})  Here I'm getting an error like this SyntaxError: expression cannot contain assignment, perhaps you meant "=="? in django  If I am changing my code like this it will work , but my issue is that I am using filtering option there so I need to get the exact field name that user passed in the dimensions dimension = ['category','amount']  // Just imaging I am getting an array like this frim request for _, obj in enumerate(qs1):     kwargs.update({obj[dimensions[1]]: Count(dimensions[1],                      filter=Q(filter_data =obj[dimensions[1]]))})

Does python have the ability to create dynamic keywords?  For example:  qset.filter(min_price__usd__range=(min_price, max_price))   I want to be able to change the usd part based on a selected currency.


What was the true extent of Guinan's abilities? I noticed in several episodes that alterations to the time stream didn't affect her, i.e. her memory was unaffected. Even more strange, Q seemed to be unsettled by her...the first time he seemed startled, even afraid. And then there's the fact that apparently her species is so long-lived that in 500 years she didn't appear to have aged a day. Can someone enlighten me?

In Star Trek: The Next Generation episode "" (Season 2, Episode 16) Q seems disturbed by the presence of Guinan to the point of raising his hands as if to use his powers on her. Guinan responds by raising her hands as if to cast a "magic" spell of her own.   Is it ever established what powers she or her race may possess?


The US state department contains this confusing statement that implies that there is an additional 90-day waiting period before I can restart a 90/180 Schengen visa. This does not match several other posts on this site.     If you spend three months in the Schengen area during any six-month period, you must wait another three months, from the last date of departure from the Schengen area, before you can apply to enter the Schengen area again without a visa. If you do not meet these conditions, or if you plan to stay in the Schengen area longer than three months, contact the embassy of the country where you plan to spend the majority of your time to apply for a visa.     Could anyone provide any insight? All of the other posts seem to indicate that a second 180 day period could begin immediately after a prior period ends.

I have searched the web a lot and could not find an answer that fits my situation. Here are two links that are quite contradictory:       My situation:  I've visited Portugal in December 2012 for 29 days on a Schengen visa valid from December 1st, 2012 to February 1st, 2013 for research purposes (I am a Ph.D. student). I want to visit Sweden from February 10th, 2013 to May 10th, 2013 (89 days). I have applied for a Schengen visa again (for research). How will the 90/180 rule work in my situation?


There are some phrases in English that lead to nothing but unnecessary confusion and frustration, especially for non-native speakers. For instance, I've seen the phrase ain't no something being used lot more than necessary. Examples:   Ghosts? There ain't no such things. There ain't no chocolates in my pockets. I ain't no magician sir, I'm just a technical person.   First of all, two negatives should cancel each other in a sentence. So "ain't" and "no", the two negatives should cancel each other out. So, the sentence There ain't no chocolates in my pocket effectively means There [are] chocolates in my pockets. Yet, in common usage, it is understood to mean There are no chocolates in my pocket. Why all this confusion? Can't you just say what you really mean to say?  EDIT: The linked answer is very related, but not an exact duplicate of what I want to ask. My question is not just about the use of negatives, but rather the confusing or ambiguous meaning resulting out of it.

I have heard many (rather most) people, especially in the USA, saying:      I don't know nothing about it.   Is that correct? I always get a weird feeling hearing this and feel the correct one would be saying:     I don't know anything about it.


Stick div to bottom of screen and when the content gets longer than the screen and you have to scroll make the div go down with the content but wont come shorter than bottom of the screen.  QUESTION: How do i get a div to stick to bottom of screen and move down when the content gets longer than the screen where you have to scroll?

I have a simple 2-column layout with a footer that clears both the right and left div in my markup.  My problem is that I can't get the footer to stay at the bottom of the page in all browsers.  It works if the content pushes the footer down, but that's not always the case.


Say f(x)= x+1.   Now $\lim \limits_{x \to 1}$ f(x), we can see easily that there is no hole in it or it is continuous everywhere. Since it is a straight line.  But when we write the same f(x) as,   f(x) = x+1 = (x+1)(x-1)/(x-1) = $(x^2-1)/(x-1)$.  $$\text{Or say g(x) }= (x^2-1)/(x-1)$$  i.e  $\lim \limits_{x \to 1} g(x)=\lim \limits_{x \to 1}(x^2-1)/(x-1)$  In this site  it says g(x) has a hole at x=1. But isn't both f(x) and g(x) are same. Please explain. Thanks.

$$\lim _{x\rightarrow 5}\frac{x^2-25}{x-5}  = \lim_{x\rightarrow 5} (x+5)$$  I understand that to evaluate a limit that has a zero ("hole") in the denominator we have to factor and cancel terms, and that the original limit is equal to the new and simplified limit. I understand how to do this procedurally, but I'd like to know why this works. I've only been told the methodology of expanding the $x^2-25$ into $(x-5)(x+5)$, but I don't just want to understand the methodology which my teacher tells me to "just memorize", I really want to know what's going on. I've read about factoring in abstract algebra, and about irreducible polynomials (just an example...), and I'd like to get a bigger picture of the abstract algebra in order to see why we factor the limit and why the simplified is equal to the original if it's missing the $(x-5)$, which has been cancelled. I don't want to just memorize things, I would really like to understand, but I've been told that this is "just how we do it" and that I should "practice to just memorize the procedure." I really want to understand this in abstract algebra terms, please elaborate. Thank you very much.


The RSS feeds (under the HNQ list) on each site's homepage somehow have the wrong label and link:  On   Bugs → Monthly Reqs → (missing) Active → Recent Bountied → Bountied (correct) Hot → Bountied Week → Hot Month → Weekly   On *  Active → Recent Hot → Bountied Week → Hot Month → Weekly   On   Apps → (missing, probably by design) Scripts → (missing, probably by design) Active → Recent Hot → Bountied Week → Hot Month → Weekly    Example:      *Not sure about Stack Overflow since Teams member is only shown "Recently Active" questions and RSS feed

The various tabs on the per-site Top Questions homepage have, at the bottom of the right nav, an RSS link for the selected tab.  However, these are currently not correct for the active tab, for most of the tabs.  For tab...   the RSS link is ...               not present (but that's probably correct)         (probably by design, but )         (correct)                              Other sites don't have all those tabs, but the ones which are present are incorrect in the same way.


Can anyone help me access Windows again?  I have Windows 10 and Ubuntu running on my machine, with GRUB as the bootloader. I wanted to disable GRUB and remove my Linux partition. Following some online tutorial, I restarted Windows in Command Prompt mode. As a result of what I did there, GRUB doesn't recognise the Windows partition any more and throws an "invalid signature" error. Ubuntu still loads with no issue.  Any clue what's happening? How can I get back to using Windows?  Please consider that   My objective is still to remove GRUB and Ubuntu, so restoring the Windows bootloader would be enough for me I'm probably not as techy as most Linux users... please keep it simple! :)   Thanks a lot for any tip!!

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 like to develop IOS native mobile application using windows 7. Is it possible ? If it is possible kindly share the information ...

Is there any way to tinker with the iPhone SDK on a Windows machine? Are there plans for an iPhone SDK version for Windows?  The only other way I can think of doing this is to run a Mac VM image on a VMWare server running on Windows, although I'm not too sure how legal this is.


I've run in to a situation that can't really explain how is this even possible.  I made a  for a demo.  THE CODE:  angular.module('test', []).controller('TestController', function($scope) {  /*   DEFAULT CONST VARIABLE */ const _DEFAULT = {   items: [],   name: 'Test',   selected: null };  /*   TEST_CASE SCOPE VARIABLE */ $scope.test_case = _DEFAULT;  console.log('ON INIT DEFAULT: ', _DEFAULT);  /*   FUNCTION */ $scope.clicked = () => {   // SET TEST_CASE.SELECTED = 1   $scope.test_case.selected = 1;    // SHOW UPDATED TEST_CASE AND _DEFAULT VARIABLE   console.log($scope.test_case, _DEFAULT); };   });  When button is clicked () we change data only in $scope.test_case so HOW is it possible that const variable _DEFAULT has the same data as $scope.test_case when _DEFAULT has never been touched or changed?   That should be impossible or am I missing something?

I have an object x. I'd like to copy it as object y, such that changes to y do not modify x. I realized that copying objects derived from built-in JavaScript objects will result in extra, unwanted properties. This isn't a problem, since I'm copying one of my own literal-constructed objects.  How do I correctly clone a JavaScript object?


As some of you have surely experienced, residential telecom installers can leave a thing or two to be desired when it comes to how they get the service into our homes.  A small project I've had in mind is to repair the extra holes in my home, and to do a better cable management job with all this coax. What do I need to repair the walls and organize this mess?  Note: I use separate providers for internet and TV   Incoming coax   Exterior coax   "Cable management"

I would like to add a new cable outlet to an outside wall and wanted to find out what kind of drill bit is needed to drill through and feed the coax cable as well as anything else to be mindful of. Comcast wanted $70 for a new outlet installation ($30 install, $40 tech visit), so I figured I could do it myself. The part that I'm most unfamiliar with is how to properly weather seal it. The outside just has vinyl siding and there's no electrical outlets nearby.  So far, I think I need the following   Coax Cable Coax Cable Wall Plate Long drill bit Add a 3-way Cable Splitter to cable box Weather sealer?


I know that on macOS you can access the last run Apple Diagnostics test in System Information, as seen in the image below.    You can also access reference codes in the Terminal using system_profiler SPDiagnosticsDataType | grep "Reference Code".  Where on disk is this information actually stored? Or how could I use Finder to access this information? I understand there are a few other questions that are asking about software diagnostics, but I am looking specifically for hardware diagnostic results. I have checked the following directories already, and have not found the Apple Diagnostics results.  ~/Library/Logs/DiagnosticReports  /Library/Logs/DiagnosticReports  ~/Library/Logs  /Library/Logs  /private/var/log  Thanks in advance!

I am trying to debug a crashed (or hanging) app. How do I get the diagnostic files from the crash?


I'm testing some software using a browser. I want to start a Chromium of FireFox session, and instruct the browser to an alternate host file. The host file will redirect a couple of domains to the local machine for testing. If the domain is not present in the alternate host file, then name resolution should proceed as normal.  I don't want to modify the real /etc/host or my DNS server because I only need the changes for local testing with a particular browser instance.  Is it possible to instruct Chromium of FireFox (or another browser) to use an alternate host file for testing? Or is there another solution that I missed?

I have a number of staging and test servers that I need to constantly modify my hosts file to access (they depend on the domain name, so I have to change the hosts file to get them to work).  I find this annoying. I'd like to setup a portable browser of some kind for each kind of site I want to work with. Is there any version of any graphical web browser (including browsers based on the rendering engines of other browsers) that will do this?  This way I can simply launch the instance that's already configured to work with staging if I want to test staging.    Any ideas?  EDIT: The important feature is the ability to run two browsers concurently, both browsing to some-address.com, but with one browser directing the reqests to the server at 1.2.3.4 and the other browser directing the requests to the server at 5.6.7.8.  EDIT: (3/16/14)  This question was asked several years ago, and I still don't know of a decent way to do this.  Let me try to explain further, because people seem to misunderstand the problem.  It's not something that can be easily fixed just by using a proxy server.  I suppose it might be possible to write extensive rules in a proxy server to solve the problems, but that's a huge complex solution to what should be a simple problem.  So to clarify:  There are three web servers.  Production, Test, and Development.  Each runs a multi-tenant application that customizes itself based on the hostname used to access it.  Conceptually, this is similar to a Content Management System or blog engine that allows multiple sites to be run off the same server instance.  You just point the hostname to the server, and whichever hostname is used to access it via HTTP 1.1 hostname mapping, is the site it displays.  Any solution which simply rewrites the host file doesn't work because of the requirement to run multiple browser windows at the same time to the different sites, production, development, test, etc...  So simply constantly altering the host file doesn't work because it affects all browser instances.  If you change the mapping for one browser, then the other browsers are also now mapped to that server so any subsequent requests will go to the wrong server.  All i'm looking for is a way to force this browser instance to use this host file, and that browser instance to use that host file, such as through a command line parameter.  I don't even care if I need to install multiple copies of the browser.    This may be doable with firefox portable, since I think it uses its own config files per installed copy, but the problem is that the third party software used to administer the sites does not work with firefox (the sites themselves do, but the admin tools do not, they work fine with chrome and IE and Opera, however.. and I have no access to the source for this to fix it).


My client's ex website was full of copy-pasted news and the website's reputation was 0. Also, he wanted to get rid of Wordpress, so we re-developed his website and did not use old data.  But Google's cache is full of old page indices, more than 500k. More, new websites slugs are different than the old ones, so all the cached indices redirect to 404 pages.  I need to remove them but search console does not provide an option to handle this much indexes. What can I do?

I've had my website hacked. I have cleaned it and searched google site:example.com and made a list of all the results. Removed the actual links that are OK and made a list of the ones in the format of example.com/ad0-b1fermarte54eb17chb-1244425. I've submitted these links to Google to remove and Google removed these links.  The problem here is that after my initial search, that resulted in 200 URLs which we've removed, other new links appeared out of nowhere. These links don't actually work anymore and return a 404 page, but Google still has these in its results.  We've tried deleting our sitemap and re-submitting it. Google has crawled it, but again, it has not removed the dummy search results.  Looking in our google webmaster console, we saw that in the coverage tab the number of indexed links spiked from 230 (normal usage) to 10.900 links - I'm guessing these are all dummy links that were infected and now cleaned.  Any magic way of having Google remove dead links automatically? Or a way to force it to recrawl the entire website?


I remember once in our Statistics class, our professor mentioned an interesting problem, that is:     In our class, consisting of 30 students, I bet that there are two students born on an exact day of year.   It was quite clear to all of us that he will lose the bet, but then he asked all the students to write out their birth date on the board and surprisingly three of us were born in the same day of year!  It was very interesting to us. He wrote the proof to his statement, showing that If there are 40 students in one classroom, the probability that at least two students are born in the same day of year is over 90 percent (as I recall).  A few days ago, I told my friends about this, they all laughed at me saying it is impossible. I tried to give them the proof but I failed. I've forgotten everything!   I guess it is a famous problem in statistics, can anyone provide the proof or any link to any docs providing the proof to this statement?

"How large must a class be to make the probability of finding two people with the same birthday at least 50%?"  I have 360 friends on facebook, and, as expected, the distribution of their birthdays is not uniform at all.  I have one day with that has 9 friends with the same birthday. (9 months after big holidays and valentines day seem to be big ones, lol..)  So, given that some days are more likely for a birthday, I'm assuming the number of 23 is an upperbound.  Has there been a better estimate to this problem?


I need to make an ubuntu installer that only shows 2 languages (in my case, English and Bahasa Indonesia).  What file in the installer ISO do I need to modify to do this?  So it is clear what I mean, see:

I would like to customize Ubuntu live CD by installing some additional packages. I have followed   but it doesn't seems to work. Can anyone provide clear instructions?   Note: I do not prefer Remastersys, manual way will be appreciated.  Customization  Packages that I want to install:   Thunderbird    Samba    SSH       Changes that I need:   Remove Games menu from the Application menu Firefox shortcut on Desktop Radiance as the default Theme Different default Ubuntu Wallpaper   Configuration file changes   I want the panel to be placed at the bottom I want to paste my Samba configuration file instead of default Samba configuration I have few Firefox shortcuts and folders I would like to show that in Desktop Also it will be nice if you say me how to change the icon sets   Recent Updates   I have customized Ubuntu 10.10 with Firefox shortcuts and few folders on desktops. Everything went smooth. But the installer gets crashes after choosing the timezone. How do i fix this issue? Also setting wallpaper affects the login screen. The wallpaper which i set is displayed on the login screen also. I just want the default one for the login screen.


My understanding is that the more general case of this (the countable union of countable sets) requires choice to prove. However in the case of ordinals, it should be provable without choice since there is an explicit well ordering on ordinals. Based on this, how does one go about constructing the explicit surjection needed to prove this?

One of my homework questions was to prove, from the axioms of ZF only, that a countable union of countable sets does not have cardinality $\aleph_2$. My solution shows that it does not have cardinality $\aleph_n$, where $n$ is any non-zero ordinal (not necessarily finite). I have a sneaking suspicion that my solution is actually invalid, but I can't find any reference which invalidates my conclusion.  I have read that it is provable in ZF that there are no cardinals $\kappa$ such that $\aleph_0 < \kappa < \aleph_1$, but I believe the conclusion of my proof does not preclude the possibility that the cardinality is incomparable to $\aleph_1$ or some such.   I think the weakest point in my solution is where I claim that the supremum of a countable set of countable ordinals is again countable. This is true, of course, but it sounds uncomfortably close to the claim "a countable union of countable sets is countable", which is well-known to be unprovable in ZF. Can anybody confirm that the ordinal version is provable in ZF though? If not, I think I can weaken the claim to "the supremum of any set of countable ordinals is at most $\omega_1$", and this establishes the weaker result that the cardinality of a countable union of countable sets is not $\aleph_n$ for any ordinal $n \ge 2$.


I've probed this serial stream coming out of a scoreboard controller and it seems like a proprietary protocol. How would I go about trying to software-decode this?    The start bit is 7.8us long. All the data bits are about 3.85us, giving a bus speed of around 260KHz. A logic HIGH bit starts with a 3.1us HIGH period then a ~800ns LOW. A logic LOW bit is the same but the periods are switched. Each packet is made of 255 bits, so about one packet is sent every millisecond.  I've thought of triggering on the rising edge and then reading the pin level after a short delay, but I don't think an interrupt-driven scheme would work that well because of the overhead.  Any ideas?

I am trying to decode a signal stream coming from a Nevco scoreboard controller:    Packets like this are sent every ~2.7 ms.  I suspect it is some sort of UART signal because it is on the RX line of a ATMEGA48, but I cannot identify the finer protocol details like parity and stop bits. All the combinations I have tried returns junk data, so it may be another encoding scheme.  What's unusual is that the same signal is also sent to the MOSI pin of the microcontroller, but there is no clock signal anywhere.  A .vcd file is .   The shortest pulses (both high and low) are always 8us in length.    This is what two packets look like. Anyone got ideas?


I think I'm supposed to use calculus somewhere but I'm completely lost.

The question I've been given is this:  Using both sides of this equation:  $$\frac{1}{1-x} = \sum_{n=0}^{\infty}x^n$$  Find an expression for $$\sum_{n=0}^{\infty} n^2x^n$$ Then use that to find an expression for $$\sum_{n=0}^{\infty}\frac{n^2}{2^n}$$  This is as close as I've gotten:  \begin{align*} \frac{1}{1-x} & = \sum_{n=0}^{\infty} x^n \\ \frac{-2}{(x-1)^3} & = \frac{d^2}{dx^2} \sum_{n=0}^{\infty} x^n \\ \frac{-2}{(x-1)^3} & = \sum_{n=2}^{\infty} n(n-1)x^{n-2} \\ \frac{-2x(x+1)}{(x-1)^3} & = \sum_{n=0}^{\infty} n(n-1)\frac{x^n}{x}(x+1) \\ \frac{-2x(x+1)}{(x-1)^3} & = \sum_{n=0}^{\infty} (n^2x + n^2 - nx - n)\frac{x^n}{x} \\ \frac{-2x(x+1)}{(x-1)^3} & = \sum_{n=0}^{\infty} n^2x^n + n^2\frac{x^n}{x} - nx^n - n\frac{x^n}{x} \\ \end{align*}  Any help is appreciated, thanks :)


What is the reason behind visual properties like color and transparency of different substances? I have always heard that the structure of the substance is responsible for these properties. I always imagined that the bond length between the atoms of the substance permits photons of only some certain wavelength. But, most bonds are in the order of $1.5\unicode{xC5} $, and by my "explanation", most materials should appear to be opaque (in the visible spectrum), but they don't. Why?

Once I asked this question from my teacher and he replied "Because it passes light.". "And why does it pass light?" I asked and he said, "Because it is transparent.".  The same question again, Why glass is transparent? Why does light pass through it, while for opaque objects, it does not?


Is any downside in always using the align environment? I.e, if I use    \begin{align} a&=b \end{align} instead of \begin{equation} a=b \end{equation} and \begin{align*} a&=b \end{align*} instead of \[ a=b \]   would I see a difference in output?

I always use align in my documents, and avoid equation. Is there anything wrong with that? My reasoning behind this: align > equation, so why not use it?


I have a visitor visa to Canada on my old passport. I renewed my passport to have. six months valid passport when travelling. can I enter Canada with a visa on my old passport? I will take both passports with me?   and do I really need a six months valid passport when entering Canada?

I recently renewed my passport. I also have an expired passport which has my Canada visa (visitor's) valid for another three years. I have already used my Canadian visa which is multiple entry. I am planning to visit Canada this summer.  Since my valid Canadian visa is in my old/expired passport, do I need to renew/transfer my Canada visa or can I simply travel with valid visa in old passport?


I am trying to switch to biber from bibtex8 and I really need the apalike settings.   I am calling   \usepackage[ uniquename=false, maxcitenames=2,  mincitenames=1, maxitems=2, minitems=1, natbib=true, url=false, doi=false, isbn=false, eprint=false, backref=true, backend=biber, style=authoryear-comp, ]{biblatex}   and I get correct citations in the text like: Bateman and Langford (1997)  but then I get  Bateman, Langford, et al. (2000) Bateman, Day, et al. (2006) Bateman, Mace, et al. (2011)  and these are wrong. I am getting extremely frustrated since the maximum number of authors set is 2 and that should reduce to 1 + et al. I think what is happening is that it is saying Bateman has many papers (which he does) and it must separate them based on authors. What is should read is this:  Bateman et al. (2000) Bateman et al. (2006) Bateman et al. (2011)  and if there are muliples it should read Bateman et al. (2000) Bateman et al. (2000a)  while in a block I would expect (Bateman et al. 2000, 2000a)  Is there an apalike set of settings which will produce the exact (and quite correct) output that I got from bibtex+apalike using biblatex and biber?

In the header of my document I set the maximal author names to 2:  \usepackage[style=authoryear-icomp, maxbibnames=9, maxcitenames=2, backend=biber]{biblatex}   Now, when I cite texts with two authors, LaTeX gives me the following:     (Author_A/ Author_B 2012: 232)   When I have three authors or more, LaTeX makes it:     (Author_A/ Author_B et al. 2012: 232)   But I want LaTeX to just name the first author if there are more than two authors ... like this:     (Author_A et al. 2012: 232)   Any tips on how to achieve this ?


In my physics textbook of class $11^{th}$ The kilogram was defined as :-       mass of the platinum-iridium standard cylinder kept at Sevre's France     But this isn't a proper and scientific definition of an important fundamental unit. When we have advanced so much in atomic physics that we are creating matter, Then why are we unable to define unit of mass?

I read that there is an effort to define a kilogram in terms that can exactly be reproduced in a lab. Why has it taken so long to get this done? It would seem this should be fairly important.  Edit: Today I got around to finding the references.  You can see the international prototype of the kilogram IPK is the artifact whose mass defines at present the SI unit of mass . You can also go  where you will see a link on the possible future revision to the SI. It sounds like this may happen in the next few years.   I am not surprised that it takes years of R&D and millions of dollars to do this. However, that's peanuts compared to what was spent on LHC. I am not saying LHC was not worth the cost - it just seems that we could have a modern definition of a kilogram by now if a few governments wanted to make it a priority.   Does anyone here know if this effort has been given the investment that it deserves?


To expect Daub to acknowledge critiques of tech thinking by women is to expect that he include not the most feminist or woke critiques of those philosophies, but the most trenchant ones.   Why he include has been used? Under what circumstances is this allowed? What is the grammar behind it?  Source:

Why is this sentence correct?     She suggested that he go to the cinema.   I would definitely use goes instead of go.


public class Student { int[] mark ; char[] grade; public int[] getMark() {     return mark; } public void setMark(int[] mark) {     this.mark = mark; } public char[] getGrade() {     return grade; } public void setGrade(char[] grade) {     this.grade = grade; }   public Student(int[] mark){     this.mark=mark;     char[] grade=new char[mark.length]; } public void findGrade(){     for(int i=0;i<grade.length;i++){         if(mark[i]>=92){             grade[i]='E';               }         if(mark[i]>=85&&mark[i]<92)             grade[i]='A';         if(mark[i]>=70&&mark[i]<85)             grade[i]='B';         if(mark[i]>=65&&mark[i]<70)             grade[i]='C';         if(mark[i]<65)             grade[i]='D';     }      }  } public class Tester { public static void main(String[] args) {     int[] marks = { 79, 87, 97, 65, 78, 99, 66 };     Student student = new Student(marks);     System.out.println("Grades corresponding to the marks are : ");      student.findGrade();          char[] grades = student.getGrade();     for (int index = 0; index < grades.length; index++) {         System.out.print(grades[index] + " ");     } }  } I dont know what is the erorr, it throws null pointer exception erorr, please explain me! it is a array program to find the corresponding grades based on marks!!

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'm trying to install Ubuntu on a Compaq laptop computer -i386 (Model R3070US) using a DVD with the ios file Ubuntu-16.04.6-desktop-i386.iso.  (The computer previously had Windows XP.)  But I cannot get past the initial BIOS error problems.  The first error that shows up is "8254 timer not connected to IO-APIC," as discussed many times on your website.  I have tried all the suggestions I can find for this problem.  I have tried every one of the special bootup options that F6 brings up:  acpi=off, noapic, nolapic, edd=on, nodmraid, and even free software only.  I have also tried practically every possible combination of these choices.  The install hangs up regardless of which of these I try. The only difference is that with some of these options I also get other error messages.  A frequent one is "No UMS support in radeon module!"  Can you suggest something else I could do to allow Ubuntu to install?  Thanks very much.

For a given hardware configuration, how do I find out if Ubuntu will run on it? What considerations should I take into account when choosing an Ubuntu version and  such as:    with a lighter desktop than the usual Gnome and Unity  with the even lighter LXDE desktop   Obviously Ubuntu does not run on some processor architectures. So how do I go about choosing the right version and derivate. How can I find out the minmal system requirements?


I've seen when the word transitioned from Godbwye to goodbwye, but when did it become goodbye?

I've heard that goodbye comes from God be with you.  Is that true?  If so how did it become good?  Did goodbye always have the same meaning it has now?


The following code will generate different values, on the same Windows 10 OS, based on what version of python you are using: import sys info = sys.getwindowsversion() major = info.major  On a Windows 10 machine, in python2: major == 6  (which is not the correct value) On a Windows 10 machine, in python3: major == 10  (the correct value) I'm in the unfortunate position of needing to use python2 here, but the values it is returning are not accurate.  Is there a module, available in python2, that will give me the accurate values for windows version information?

Possible Duplicate:          As the title says, how can I find the current operating system in python?


Let's say I have this command:  /sbin/ifconfig|grep inet|head -1|sed 's/\:/ /'|awk '{print $3}'   Is it possible to shorten this to let's say writing host in the command line?

I would like to create an alias to rm command in order to have a confirmation message after executing this command. So I am creating an alias like this alias rm='rm -i'. But as far as I know this is a temporary alias and it lives until you close the terminal.  As it is explained  to save alias permanently I need to execute ~/.bash_aliases or ~/.bashrc commands in terminal and add my alias there. But when I execute ~/.bashrc I get following error message :  bash: /home/bakhtiyor/.bashrc: Permission denied   When I run ~/.bash_aliases I get another error message like this:  bash: /home/bakhtiyor/.bash_aliases: File or directory doesn't exist.   What is the actual problem and how can I solve it?


Consider the following code:  List<String> myList = Arrays.asList(1, 2, 3); String[] myArray1 = myList.toArray(new String[myList.size()]); String[] myArray2 = myList.stream().toArray(String[]::new); assert Arrays.equals(myArray1, myArray2);   It seems to me that using a stream is much simpler.   Therefore, I tested the speed of each.  List<String> myList = Arrays.asList("1", "2", "3"); double start;  start = System.currentTimeMillis(); for (int i = 0; i < 10_000_000; i++) {     String[] myArray1 = myList.toArray(new String[myList.size()]);     assert myArray1.length == 3; } System.out.println(System.currentTimeMillis() - start);  start = System.currentTimeMillis(); for (int i = 0; i < 10_000_000; i++) {     String[] myArray2 = myList.stream().toArray(String[]::new);     assert myArray2.length == 3; } System.out.println(System.currentTimeMillis() - start);   The result is that using the stream is about four times slower. On my machine, 816ms (stream) vs 187ms (no stream). I also tried switching the timing statements around (myArray2 prior to myArray1), which didn't effect the results much. Why is this so much slower? Is creating a Stream so computationally intensive?  I followed @Holger's advice and studied up a bit (surely not enough) on JVM testing, reading , , , and using .    Results (via JMH):  private static final List<String> myList = IntStream.range(1, 1000).mapToObj(String::valueOf).collect(Collectors.toList());  @Benchmark public void testMethod() {     String[] myArray = myArrayList.stream().toArray(String[]::new); }      StreamToArrayArrayListBenchmark.testMethod  avgt    5  2846.346 ± 32.500  ns/op   private static final List<String> myList = IntStream.range(1, 1000).mapToObj(String::valueOf).collect(Collectors.toList());  @Benchmark public void testMethod() {     String[] myArray = myArrayList.toArray(new String[0]); }      ToArrayEmptyArrayListBenchmark.testMethod  avgt    5  1417.474 ± 20.725  ns/op   private static final List<String> myList = IntStream.range(1, 1000).mapToObj(String::valueOf).collect(Collectors.toList());  @Benchmark public void testMethod() {     String[] myArray = myArrayList.toArray(new String[myList.size()]); }      ToArraySizedArrayListBenchmark.testMethod  avgt    5  1853.622 ± 178.351  ns/op     private static final List<String> myList = new LinkedList<>(IntStream.range(1, 1000).mapToObj(String::valueOf).collect(Collectors.toList()));  @Benchmark public void testMethod() {     String[] myArray = myArrayList.stream().toArray(String[]::new); }      StreamToArrayLinkedListBenchmark.testMethod  avgt    5  4152.003 ± 59.281  ns/op   private static final List<String> myList = new LinkedList<>(IntStream.range(1, 1000).mapToObj(String::valueOf).collect(Collectors.toList()));  @Benchmark public void testMethod() {     String[] myArray = myArrayList.toArray(new String[0]); }      ToArrayEmptyLinkedListBenchmark.testMethod  avgt    5  4089.550 ± 29.880  ns/op   private static final List<String> myList = new LinkedList<>(IntStream.range(1, 1000).mapToObj(String::valueOf).collect(Collectors.toList()));  @Benchmark public void testMethod() {     String[] myArray = myArrayList.toArray(new String[myList.size()]); }      ToArraySizedArrayListBenchmark.testMethod  avgt    5  4115.557 ± 93.964  ns/op     To summarize:                | ArrayList | LinkedList stream        | 2846      | 4152 toArray sized | 1853      | 4115 toArray empty | 1417      | 4089     Using JMH (possibly naively), I'm still seeing that ArrayList::toArray is about twice as fast as Stream::toArray. However, this does seem to be because of the ability of the ArrayList to just do an array copy, as @Andreas pointed out because when the source is a LinkedList the results are about equal.  It's definitely good to know about myList.toArray(new String[0]).

How do you write (and run) a correct micro-benchmark in Java?  I'm looking for some code samples and comments illustrating various things to think about.  Example: Should the benchmark measure time/iteration or iterations/time, and why?  Related:


I'm trying to understand equation 5.11 from Lehmann and Casella's Theory of Point Estimation (2nd edition) which is presented without proof.   It states that if $I(\theta)$ represents the Fisher information that $X$ contains about the parameter $\theta$ and $\theta = h(\xi)$ where $h$ is a differentiable function, then $I^*(\xi)=I(h(\xi))*(h'(\xi))^2$ where $I^*(\xi)$ represents the Fisher information that $X$ contains about the parameter $\xi$. In this case, $\theta$ and $\xi$ are both scalars (I know this can be generalized to the case where both parameters are vectors, but I'm not worried about that part yet).  I don't see exactly why this is true. I'm guessing it has something to do with the chain rule, but I tend to get lost in the notation. I suppose we can write $I(\theta) = I(h(\xi)) = \int ( \frac{p'[f(x,h(\xi))]\frac{df}{dh(\xi)}}{p[f(x,h(\xi)]} )^2 p[f(x,h(\xi)] dx$  Note that $\frac{p'[f(x,h(\xi))]\frac{df}{dh(\xi)}}{p[f(x,h(\xi)]}$ is the derivative of the score function for density $p_{\theta}(x)$  Then $I(\theta)*(h'(\xi))^2= \int ( \frac{p'[f(x,h(\xi))]\frac{df}{dh(\xi)} \frac{dh(\xi)}{d\xi}}{p[f(x,h(\xi)]} )^2 p[f(x,h(\xi)] dx = \int ( \frac{p'[f(x,h(\xi))]\frac{df}{d\xi}}{p[f(x,h(\xi)]} )^2 p[f(x,h(\xi)] dx$  But this isn't $I^*(\xi)$. Or is it? Or is my understanding/notation just totally backward? I'd really appreciate any insight that you all may have in regards to this problem.

Suppose that $X$ is a random variable for which the p.d.f. or the p.f. is $f(x|\theta)$, where the value of the parameter $\theta$ is unknown but must lie in an open interval $\Omega$.  Let $I_0(\theta)$ denote the Fisher information in $X.$  Suppose now that the parameter $\theta$ is replaced by a new parameter $\mu$, where $\theta = \psi(\mu)$ and $\psi$ is a differentiable function.  Let $I_1(\mu)$ denote the Fisher information in $X$ when the parameter is regarded as $\mu.$  Show that $$I_1(\mu) = [\psi'(\mu)]^2 I_0[\psi(\mu)].$$  How would I do this?  Do I need to use a Taylor expansion?  Regardless, I would appreciate a written proof.  This isn't for class but the above statement has been mentioned in texts without any detail whatsoever.  Thanks!


What's the difference between these two questions?      Speaker A: Your car looks very clean.          Have you washed it?   Did you wash it?

In the US, when people work together, they may look for a colleague or any person to say something or for any other reason, asking colleagues or other people this type of question:         Have you seen Michael?   (OR)        Did you see Michael?          Which is considered right if the question refers to an activity (in our case "see") during the day and not in the past in general?


the javascript below are tested in codepen but when it is not working in my webpage.  the function supposed to freeze the first column of my table, the header remain static when I scroll my table to the left. after some discussion in the comments below it could be due to the html table is dynamically created, I am looking for help to convert the js below to handle this case.  $(document).ready(function() {   $('.main-table tbody').scroll(function(e) {     $('.main-table thead').css("left", -$(".main-table tbody").scrollLeft());     $('.main-table thead tr th:nth-child(1)').css("left", $(".main-table tbody").scrollLeft()-2);     $('.main-table tbody tr td:nth-child(1)').css("left", $(".main-table tbody").scrollLeft()-2);   }); });   a few attempts to make it work for dynamically created table but still not working.  can someone help to point out what i did wrong here:  $(document).on('scroll', '.main-table tbody', function(){     $('thead').css("left", -$("tbody").scrollLeft());     $('thead tr th:first-child').css("left", $("tbody").scrollLeft()-2);     $('tbody tr td:first-child').css("left", $("tbody").scrollLeft()-2); });

I have a bit of code where I am looping through all the select boxes on a page and binding a .hover event to them to do a bit of twiddling with their width on mouse on/off.  This happens on page ready and works just fine.  The problem I have is that any select boxes I add via Ajax or DOM after the initial loop won't have the event bound.  I have found this plugin (), but before I add another 5k to my pages with a plugin, I want to see if anyone knows a way to do this, either with jQuery directly or by another option.


I'm talking about those holographic designs you sometimes see on stickers and foil, not free floating holograms. .  I also want this to change colors as real ones do when you rotate them.  I came across  that shows it's possible, but it doesn't list a method.  It's similar to iridescence, . I don't see a clear path from the linked iridescence example to what I want.

Is it possible to create an  shader in Cycles? Specifically for something like , , , etc..


I develop "on the road" using a laptop that's not connected to a power source, so when I debug on my android devices, they drain my laptop battery.  Unfortunately, the laptop is a MacBook Air so spare laptop batteries is not an option.  (I charge everything at home at night.)  Is there a setting to switch USB charging off, especially when debugging?

For some reasons not related to the battery life, I need to disable the battery charging when a USB host is connected to my phone (a rooted Nexus 4). Taking a look around on the internet (, ), it looks like I should modify a system file. I have found a series of interesting files located in /sys/class/power_supply/battery and /sys/class/power_supply/usb, that could be the right ones to be modified in order to achieve the usb charging disabling (e.g. /sys/class/power_supply/usb/present 0/1).   Has anyone tried something like that (control the usb charging via software and modify such system files)? Which is the best way to modify those system files? Should I use the adb shell or another tool?  I tried the "root explore" app in order to modify those files, however when I modified a file (after changing its permissions), it was automatically kept back to its original value.


1) Trying to record secure website. 2) Error is displaying -- can't record secure website.  Please help to record and send me the steps and settings how to record secure script in JMeter.  Thanks in advance.

I'm using Apache JMeter 2.3, which now supports "attempt HTTPS spoofing" under the Proxy Server element.   I've tried this on several different servers, and have had no success.  Has anyone been able to successfully record from an HTTPS source with this setting?  Or barring successfully recording, can anyone share a work-around? When available, I simply have HTTPS turned off at the server level, but this is not always feasible. Thoughts?


Ok, see this word entertainment has IPA of /en.təˈteɪn.mənt/. Ok, now in American English if /t/ is between 2 vowel sounds  then it will become /d/ cos it is flap T.  But /t/ will become flap T only if the sound in the word is not stressed. Is that correct?  For example, for the above example, we can pronounce /en.dəˈteɪn.mənt/ but not /en.dəˈdeɪn.mənt/, right?

Why, in American English, is the word Italy is pronounced /ˈɪdəli/ and not /ˈɪtəli/? What is the rule that is followed in the pronunciation of Italy to make the letter t pronounced like a d? Why is the same rule not followed for Italian, which is pronounced /əˈtæljən/ or /ɪˈtæljən/?


The title Mrs. stands for mistress, but some English native speakers claim mistress is only used to indicate the woman with whom one has an (illicit) affair and that missus is the long version of Mrs.  I'd like to know what happened historically () to the evolution in meaning of the two terms.  Also, the NGram Viewer shows mistress to be predominant in its books (which of course says nothing on the meaning).

Wasn't Mrs. short for mistress? Why do we read Mrs. as missus(or sometimes missis) instead of mistress?


I have a little question regarding diagonalizable endomorphisms:  Let $V$ be an finite-dimensional vectorspace of some field $K$. Let $f,g:V\rightarrow V$ be diagonalizable endomorphisms such that $f\circ g=g \circ f$. We denote the eigenvalues of $f$ and $g$ with $\lambda_1,\dots,\lambda_k$ and $\mu_1,\dots,\mu_l$:  If $A_f^B$ and $A_g^B$ are the associated matrices of $f$ and $g$ with repsect to the basis $B$, show that there exists a basis $B$ of $V$ such that $A_f^B$ and $A_g^B$ are in a diagonal form. Unfortunately I don't quite know where to start. I know that it's equivalent to there being a basis $B$ of $V$ such that I'm able to choose $dim(V)$ linear independant vectors such that each vector is element of both eigenspaces $E(A_f^B,\lambda_i)$ and $E(A_g^B,\mu_j)$ for some $i$ and $j$.  Does anybody have an idea?  Thanks for checking in ;)  ~Cedric

Two $n\times n$ matrices $A, B$ are said to be simultaneously diagonalizable if there is a nonsingular matrix $S$ such that both $S^{-1}AS$ and $S^{-1}BS$ are diagonal matrices.      a) Show that simultaneously diagonalizable matrices commute: $AB = BA$.      b) Prove that the converse is valid, provided that one of the matrices has no multiple eigenvalues. Is every pair of commuting matrices simultaneously diagonalizable?   My attempt:  a) Let $M=S^{-1}AS$ and $P=S^{-1}BS$, then it follows that $A= S^{-1}MS$ and $B=S^{-1}PS$. Thus $AB =S^{-1}MSS^{-1}PS = S^{-1}MPS = S^{-1}PMS$ (is it wrong that I switched MP to PM?) $=S^{-1}PSS^{-1}MS=BA$.   b) How can I do this?


I recently browsed WooCommerce source, and it appears that they're doing this:  <?php /**  * The template for displaying product content within loops.  *  * Override this template by copying it to yourtheme/woocommerce/content-product.php  *  * @author      WooThemes  * @package     WooCommerce/Templates  * @version     1.6.4  */    if ( ! defined( 'ABSPATH' ) )  exit; // Exit if accessed directly  global $product, $woocommerce_loop;   So I did some reading about checking if ABSPATH is defined - it appears to be used for security purposes.   However, I don't see _s theme ( developed by automattic ) doing anything with ABSPATH, so my question is - is this a plugin thing, a paranoid thing, a best security practice ? Who should be checking for ABSPATH ?   Should I check for ABSPATH in my theme files ? Custom function files ? Should I check at all ?

I've run across the following snippet in themes from time to time:  if ( ! defined('ABSPATH')) exit('restricted access');   It's at the beginning of some (all?) PHP files in a theme and it's supposed to prevent direct access of the file by nefarious sources.  I see that this isn't included in Twenty Ten or Eleven and I've never seen it recommended in official WordPress documentation. It seems like a good idea to me, but I also don't know enough about security to judge it and can't find much with Google.  Is this something I should have in my custom themes? If so, should it be in all PHP files or just some?


Graph G is bipartite graph, I want to just count number of perfect matching. Is there any algorithm exist using combinatorial+graph theory, by which i cant count this. I tried by traversing the graph, but as there are so many possibilities and I just want number of perfect matching I asked here.

My actual question is to find the number of transversal given a collection of set ...  After a little bit of study it has come down to:  How can we count the number of matchings in a bipartite graph with parts of size $m$ and $n$ such that it covers all $m$ vertices of the first part, $m \le n$?  I already know that there is a way to count the number of perfect matchings in a bipartite graph with $m=n$ using the permanent of its (square) incidence matrix.


Now dont get me wrong, i did everything i possible can to ensure that my smtp server is GOOD, i use high quality content so this is not content issue.  i never sent email to anyone besides my self for testing, and its all going to spam.  i have DKIM/SPF/_dmarc, google-dns-verification, PTR/Reverse proxy or w/e it called, it all set 100% working and i can see in gmail on the source tab that all PASS.  i checked my server on multiple testing websites such as:  and got 9.2  i checked that my IP is NOT blacklisted and its not.  i did everything i possible can to ensure my emails are OK but gmail still decides to throw me into spam (i tried to sent to 4-5 accounts not to one account only )  this is my email server -  teamsvoice.com / mail.teamsvoice.com  i installed iredmail included working SSL certificates anyone can think of Anything i haven't thought about?

When sending or forwarding emails using a personal or company domain using a  website or email client, how do I prevent the email from being incorrectly marked as spam?


We remember the definition of strong convergence of a sequence in $B(H)$ for $H$ a Hilbert space: $a_n\rightarrow a$ iff $\left\|a_nx-ax\right\|\rightarrow0$ for all $x\in H$. In general norm convergence implies strong convergence, but the converse isn't true in general. But it seems to be special cases: Let $(a_n)$ a sequence in $B(H)$ which converges strongly to an operator $a\in B(H)$. Furthermore assume that $b$ is a compact operator. The claim is that the sequence $(a_nb)$ converges in norm (operator norm) to $ab$. I can't find a good reason of estimation to conclude that this should be true. Moreover if we take the sequence $(ba_n)$ then the conclusion that this converges to $ba$ isn't true. I think you have to use projections to find the counterexample, but more interesting is the question why $(a_nb)$ well converges. Can someone help me with this problem? Thank you very much.

I need some help with functional analysis / Hilbert space theory. If you have a favorite text to recommend, please let me know~  Here is my question:  Given $v_t$ be the "squeeze operator" on $H=L^2[0, 1]$, where $v_t: L^2[0,1] \to L^2[0, \frac{2-t}{2}]$ acts on $f \in L^2[0,1]$ by squeezing the domain of the function. We have that $\{v_t\}$ for $t \in [0, 1]$ is a family of SOT continuous operators. I am wondering why given any $p \in \mathbb{K}(H)$, we have $\{ v_tpv_t^* \}$ is continuous in norm.  I found the following facts on a reference suggested by Wikipedia (Hilbert Space Operators in Quantum Physics), but I am not sure how to prove them or how I may use them...   $T_n \to^{SOT} T$ implies that for any $p \in \mathbb{K}(H)$, we have $T_np \to Tp$ in norm.   Hints or suggestions would be greatly appreciated!


What is the difference between ref and out parameters in .NET? What are the situations where one can be more useful than the other? What would be a code snippet where one can be used and another can't?

I'm creating a function where I need to pass an object so that it can be modified by the function. What is the difference between:  public void myFunction(ref MyClass someClass)   and  public void myFunction(out MyClass someClass)   Which should I use and why?


Is there a way to define rendering in multiple ranges in the timeline? For Example:  I like to render the scene from frame 0 to 191 and from 266 to 400. (I don't want to render from 191 to 266, because therefor I have prepared a separate scene with less objects) Is there a solution without scripting? Because I have no experience in python or any scripting language.

I’m making a little movie with using multiple computers. I can't use the network so I've divided the frames of the animation over the computers. Unfortunately now there are frames missing. What I'd like to do is using 1 machine to render all the missing frames. For example: 4-24-35-64-143 but ideally in such a way that I don't have to re-start blender multiple times. Is this possible somehow?


Obviously, upvoting your own question as an alt account is voting fraud, but what if I were to downvote my own question as a sockpuppet? How would that look?

A high-reputation, highly-active user has already been dinged once for a sockpuppet, and I just dinged him again. He probably has another sockpuppet as well.   What are the guidelines for handling users who game the system in this fashion? Specifically,   How can I be sure I'm looking at a sockpuppet? When should sockpuppets be considered a problem? How should moderators handle problematic sockpuppets once they've been identified? I was suspended for sockpuppetting and feel this is unfair


Sometimes, just to make sure all files are private, a command  sudo chmod -R 000 .   If we want to change back the permissions back to "normal", what command can be used?  sudo chmod -R 777 .   will not work because it makes some files that are not supposed to be executable become executable.  The executable flag is need for directories to be able to be accessible.

I have moved contents of another drive into my home directory, but the permissions are not what they should be. First, I changed ownership by entering:    ~$ sudo chown -R USERME /home/USERHOME/   Which I think works now.  But now, I wanted to simply change all of the files and sub-directories into the default permissions, with files being read+write, and directories being r+w+x. I have not found a recursive way of handling this. I have run:    ~$ sudo chmod 755 -R /home/USERHOME/   To make everything available to me. However, files appear as executables, and this is not what I want. There are plenty more sub-directories and files so I am looking for a simple recursive solution.  Basically, I think I am looking for a recursive way to reapply the default umask parameter to a whole folder with (I think) chmod.    Update:  I have posted a solution thanks to @SkyDan and