Zorn's lemma states that: Suppose a partially ordered set P has the property that every chain in P has an upper bound in P. Then the set P contains at least one maximal element. Suppose $P$ satisfies the assumption to apply the Zorn's lemma. Does it then follow that given any $x \in P$ there exists a maximal element $m \in P$ such that $x \leq m$? ps also by chain I thought it was of the form $x_1 \leq x_2 \leq x_3...$ Is this correct? Thank you

If $A$ is a poset in which every chain has an upperbound in $A$ ($a$ be any element in $A$). There exists at least one maximal element $m$ in $A$ such that $m \geq a$.  Whats the difference between this and Zorn's Lemma?


I am trying to find the file(say marks.txt) in the particular path passed as argument to a function. Is it possible to give the filename and path as arguments to a function which checks if the file exists and prints out the path?   The below function only takes path as argument.   int fileexists(const char *path){                                      File *ptr = fopen(path, "r");                                                  if (fptr == NULL)                                                                                return 0;     fclose(fptr);     return 1; }           The required function prototype :  int fileexists(const char *path, const char *filename)

Is there a better way than simply trying to open the file?  int exists(const char *fname) {     FILE *file;     if ((file = fopen(fname, "r")))     {         fclose(file);         return 1;     }     return 0; }


Let $(x-1)^3$ divides $p(x)+1$ and $(x+1)^3$ divides $p(x)-1$. Find a polynomial $p(x)$ of degree 5. Here's what I have tried:—  As $(x-1)^3$ divides $p(x)+1$, $p(1)+1=0$, $p(1)=-1$ $p(-1)=1$ Letting $p(x)=a_5x^{5} + a_4x^{4} + a_3x^{3} + a_2x^{2} + a_1x + a_0$  I don't know how to proceed any further. I think the divisibility rule is gonna be used somewhere.

I have been trying to find a polynomial $f(x)$ such that these $2$ properties hold:   $f(x)-1$ is divisible by $(x-1)^3$ $f(x)$ is divisible by $x^3$   To start, I set $f(x) =ax^5 + bx^4 + cx^3 + dx^2 + ex + f$. This is divisible by $x^3$, so $d, e, f $  must be $0$. So polynomial $f(x) = ax^5 + bx^4 + cx^3$  This minus $1$ is divisible by $(x-1)^3$. So I used synthetic division and got that the remainder of $ax^5 + bx^4 + cx^3$ divided by $(x-1)$ is $a+b+c-1$. But it should divide out evenly, so $a+b+c-1 = 0$.  From here, I can't find any other equations involving the three variables. Could someone have any suggestions for how to continue? Thanks in advance. :)


I am running as follows Jenkins on my server:  $> labes@labes-jenkins:~/jenkins$ java -jar jenkins-1.622.war   But when I unplug my machine the application of jenkins goes down, as I do to get the application running at the same end my SSH session?  Note: Jenkins has the jetty embedded server inside the .war artifact.

I'm connecting to a Linux machine through SSH, and I'm trying to run a heavy bash script that makes filesystem operations. It's expected to keep running for hours, but I cannot leave the SSH session open because of internet connections issues I have.  I doubt that running the script with the background operator, the ampersand (&), will do the trick, because I tried it and later found that process was not completed. How can I logout and keep the process running?


After reading the question regarding "Why is there something instead of nothing?" I stumbled over the first part of "" answer:     Before anything else one should be aware of the instrument used to   answer questions.  That instrument is human language. While there is   no guarantee that such a system of patterns is powerful  and   expressive enough to reason about the necessity of all that is, we can   still examine what can we reasonably say  and understand about this.   While this seems true, I think this goes even further, right to the inability to think of non-existance.  Language and thinking are closely connected, but I am convinced that thinking in pictures allows us to think "better" in a way that we can now think about issues we couldn't express in words.  So after reading the mentioned answer, I tried to think of a non-existing universe.     I Take a picture of an empty, white colored room.   So far so good, remove the "boundaries", the walls   Now I just think of a undefined white space.   White seems to force the existence of something causingthe space to be white.   I think of a black undefined space.   While this seemed like "nothing" to me first, on the second glance it it something, but with nothing in it.  Maybe I can make it tranparent. but transparent means you can see though. And what can you see then? Something. It is ridiculous to try picture nothing, because I want to have something in my head then.  Now we are back to the language boundaries.  For me it seems impossible for any thinking creature to think of nothingness because we think of something then.  But until know this is just coming to the same conclusion after thinking about the answer I was referring to.  So here comes my question (of two parts): Are there any fallacys in the way my tought went, and nothingness can be described in any way?   If that isn't the case, re there any elaborations on the topic of what can be deducted from the inability  to imagine/pictrue/describe/ etc. nothing?

It's possible to imagine something, for example a table, we see one everyday and can bring it in front of our minds eye (although it's a moot point whether we can see it - I certainly don't). But of course this is a real object so we have a referent. But we need not have a referent: to imagine a unicorn means we are hybridising our referents.   But to imagine nothing in its proper sense (ie not the lack of something or just space) seems impossible to me, we cannot avoid our sense of ourselves.


Why do Calabi-Yau manifolds crop up in String Theory? From reading "The Shape of Inner Space", I gather one reason is of course that Calabi-Yaus are vacuum solutions of the GR equations. But are there any other reasons?  Also, given those reasons, what tend to be the most physically suggestive and useful or amenable forms among the widely different expressions obtainable by birational transformations and other kinds?  Actually, just some examples of C-Ys, and what they are supposed to represent, would be very interesting.

I was hoping for an answer in general terms avoiding things like holonomy, Chern classes, Kahler manifolds, fibre bundles and terms of similar ilk. Simply, what are the compelling reasons for restricting the landscape to admittedly bizarre Calabi-Yau manifolds? I have  but haven't read it yet, nor, obviously,  :)


When I want to move/rotate/scale with a defined spacing or amount of units I use the ctrl key but it moves one whole blender unit, does anyone know how can  I change this spacing so that it moves 0.1 blender units?

I would like to know how to change the increments used for snapping transforms.  This would be useful in a number of situations but my problem now is that when I change the units it does not scale the snapping increments to match.  So when holding down ctrl the cube snaps from here:    To here:    I would like it to snap to the 1 foot grid, or possibly any other amount I find useful.  It would also be nice to be able to change the rotation snap as well.


im just getting my head around container classes and templates, and am having trouble working out how to implement them properly.. all of my problems are pretty similar, so once i get this sorted, i think i should be okay..  here is the code for the push_back member function that i am trying to implement:  //data is of type boost::ptr_vector<T>  template <class T> void P_VContainer<T>::push_back(T* item) {     data.push_back(item); }   this is how it is defined in p_vcontainer.h:  void push_back(T* item);   this is the error im getting from the compiler:  main.cpp:(.text+0x89f): undefined reference to `P_VContainer<Customer>::push_back(Customer*)'   this is how i am implementing it in main:  P_VContainer<Customer> myvector;  Customer *a = new Customer("C004", "Testy McTestington");  myvector.push_back(a);   any ideas as to what im doing wrong?

Quote from :     The only portable way of using templates at the moment is to implement them in header files by using inline functions.   Why is this?  (Clarification: header files are not the only portable solution. But they are the most convenient portable solution.)


So I became Thane of Riften and got Iona as a housecarl and I married. She was in my house but after a while she just disappeared from my house and isn't anywhere in riften, from what it seems. Any idea where she would be? I also have not gotten a letter from a courier to inform that she has been killed.

I had parked my follower at an inn with a bunch of valuable items that I didn't want to carry. I guess I have been out a bit too long as this message appears:      Your follower tires of waiting and leaves.    There have been other situations where my follower has mysteriously disappeared as well.  How can I find my follower when they get up and leave or disappear into thin air?


In what way are each intended to be used? Also the differences between them?  For an example:  sbyte myByte = 1; SByte myByte = 1;

Example (note the case):  string s = "Hello world!"; String s = "Hello world!";   What are the guidelines for the use of each? And what are the differences?


I want to enable "show desktop icon to the launcher" as in ubuntu 16.04. I cannot find the why. Is this option somewere in ubuntu 18?

I am migrating from Unity to GNOME. One item I am missing is a "Show desktop" button (aka "minimise all windows") in the dash. How can I add this functionality to the GNOME dash (or Ubuntu dock in Ubuntu 17.10 and later), even if it means making a custom .desktop file?  (I know that I can use the Ctrl + Super + D   and that I can install , but I specifically want a button in the dash.)


I have a very weird problem. I have a crontab which looks like this (this is the output of crontab -l:  * * * * * touch /home/<user>/Desktop/crontest.txt   A sample output of sudo grep CRON /var/log/syslog gives:  Jun 19 09:49:01 set-l-me-l16039 CRON[8399]: (u0128861) CMD (touch /home/<user>/Desktop/crontest.txt)   Yet no file is created in my Desktop! Running the command in the terminal produces the text file crontab.txt but the cron job doesn't. I'm running Ubuntu 18.04.  EDIT: I use crontab -e to edit my crontab. Also I should mention that the same happens on my other machine running Ubuntu 18.04.

Often, crontab scripts are not executed on schedule or as expected. There are numerous reasons for that:   wrong crontab notation permissions problem environment variables   This community wiki aims to aggregate the top reasons for crontab scripts not being executed as expected. Write each reason in a separate answer.  Please include one reason per answer - details about why it's not executed - and fix(es) for that one reason.  Please write only cron-specific issues, e.g. commands that execute as expected from the shell but execute erroneously by cron.


After the Spring 15 update I am not able to schedule more than 5 apex jobs. These are NOT BATCH jobs but are being scheduled using the system.schedule. Before the update I was able to create more than 30 similar jobs but since the update i get the governor limit error.  has anyone encountered similar problem ?

After the upgrade of salesforce to Spring 15, I am getting this error "Error: You have exceeded the maximum number (5) of Apex scheduled jobs." when scheduling more than 5 batches. I have this issue in several environment. I used to more than 20 batches scheduled at once.   On the link below, it says that I can schedule up to 100 batches but I am being restricted to 5 only.   I can't have more than 5 jobs here.


I need to use a package X. X depends on Y so I need the dev package of Y (Y-dev). I also have Y's source. How may I compile Y-dev from Y's source?  If this question is incoherent please point me in the right direction on how to avail a package Y that X depends on.  Specifics:  X is R-2.15.3  Y is readline-6.2  I downloaded readline-6.2 and installed it to $HOME/software. I also set   $C_INCLUDE_PATH=$HOME/software/include:$HOME/software/include/readline  and  $LD_LIBRARY_PATH=$HOME/software/lib:$HOME/software/lib64  I have the following readline files in $LD_LIBRARY_PATH:  /home/paulk/software/lib/libreadline.a /home/paulk/software/lib/libreadline.old /home/paulk/software/lib/libreadline.so /home/paulk/software/lib/libreadline.so.6 /home/paulk/software/lib/libreadline.so.6.2 /home/paulk/software/lib/libreadline.so.6.2.old   When I run ./configure --prefix=$HOME/software for R-2.15.3 I get  configure: error: --with-readline=yes (default) and headers/libs are not available.  My distro is Scientific Linux, which is RPM-based.

Compiling and installing software is a pain and problem I cannot overcome. I just want to run down through my understanding of this process with someone more knowledgeable to clear my mind to get to the next level.   Many scientific software I need are not distributed as packages. I understand "./configure" sets up the compilation variables and checking for dependencies "make" does the compilation "sudo make install" puts all the libraries and bins in their places. However it never works. I rarely get out of the a) "./configure" stage without entering dependency hell, and if I do, b) "sudo make install" will probably nuke my box.   a) The dependency hell is very frustrating. Sometimes I have the library, but it doesn't like it. Or the library doesn't want to install. Or "configure" can't find it. Or my distro placed it somewhere it shouldn't be. Or there are two versions in my system. Problem is, I can't understand how to diagnose and therefore fix these problems. What are some good references to learn for someone who doesn't need to become a programmer?  b) My understanding is "make install" will replace some libraries and change settings without my package manager being aware of this. Therefore, some programs won't run, others can't be updated.  So, if I don't use "make install", and just keep the compiled binary in my user directory with a symbolic link added to the PATH, will I be in the clear?   My box is single user, has tons of free HD so I don't really care about having multiple (dozens) of copies of libraries if that will solve my problems. Space is cheap.


I was wondering why in some cases, both phrases mean the same thing, and one phrase has the plural -s and the other does not? Eg:     Collecting stamps (plural -s)   Stamp collecting (no plural -s)   Is that in the 1st scenario, the word "stamps" is a complement to the gerund "collecting" and in the 2nd scenario, "stamp" acts as an adjective and the linguistic structure of an adjective does not have the plural -s?

Sorry for the title, it is not very evident and intuitive but I really do not how to tell it better...  Well, you know, several times, or better, many times, we use this form:  If I want to say:      "development of special weapons was   the first point in Hitler's   program..."   I will say this (a better form):      "special weapon development was..."   OK...  is it      "special weapon development"   or      "special weapons development" (note   the plural...)   what's the grammar rule in order to understand how to use this very used form?


Always confused about this stuff. Anyone can help?

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


At the end of a memory sequence you have the option to rate it. What is the purpose of this.  Is it used in-game by Abstergo in some way, or does it get sent to Ubisoft for them to use however they like?

At the end of each mission in Assassin's Creed IV, players have the opportunity to rate the mission.  Does this feedback actually go back to Ubisoft?


I'm relatively new to Java so I'm kind of lost here. Is it wrong when you are trying to compare two strings just use the identical symbol "==" instead of using a method for checking if two strings are identical. Because for what I have tried the first option doesn't work and I'm very curious on the reason behing it


I assume it's commonly known around here that USB cables have both wires for communicating data, as well as for sending 5V of power to the device. I commonly tether my computer to my smartphone to get internet through USB, but if I've got heavy usage, the battery in my smartphone slowly dies faster than the low power from my computer can charge it.  I'd like a special USB wire that has a micro plug on one end, but splits to two A plugs on the other. This way I can plug the data portion into my computer, but plug the power portion into the phone's normal AC adapter. I'm assuming the much higher current from the regular charger will keep the phone powered regardless of heavy usage or not.  I was thinking of making this myself, but I thought I couldn't be the first person who wanted something like this. Is there an existing wire that does what I want? Or perhaps an adapter?

If the host computer for an USB device doesn't provide enough power for a device which has no dedicated power port, can I connect the power-only-plug of a Y-USB-cable to an other computer, an USB-charger or even a regular mobile charger? I'm afraid this could damage some of the devices.  Edit: The device in question is a USB Hard drive (Samsung S2 Portable 640GB (but on the back it's written to use 0.85A)) which is supposed to work whit just a single USB port. It did so well on a other laptop and whit some cables even on my actual net book back in Europe. But now in Malaysia it works only some times (I still try to figure out what the conditions are) and then it stops working after a while (maybe when it goes to power save mode). I heard from others their hard drives need one more power plug here in Malaysia to but can't imagine why...


When we see Snape's memories in DH Dumbledore's portrait tells Snape that he must tell Voldemort the right date Harry will be moved from Privet Dr because Voldemort believes Snape so well informed. But why would he still be considered well informed about the Order and Ministry's plans now that both believe him to be a Death Eater who murdered Dumbledore?

"You will have to give Voldemort the correct date of Harry's departure from his aunt and uncle's," said Dumbledore. "Not to do so will raise suspicion, when Voldemort believes you so well informed."   Snape had just killed Dumbledore, why would it raise suspicion about the movements of Harry's departure? it would seem likely that once Dumbledore died at the hands of Snape the Order would surely have changed any plans they would have had in place for Harry's exit from Privet Drive?


I just saw the proof that  $$1+2+3+\cdots=-\frac{1}{12}$$ and my brain still hurts.   I completely understood the proof and my question is NOT actually about the proof itself. At the end of the proof, they said that this answer shows itself in quantum physics (e.g. it has a role in why there are 26 dimensions in string theory).  Sadly though, I am no expert in quantum physics and I'm wondering are there any other  physical and/or mathematical situations that this counter intuitive result shows itself?  P.S. Needless to say, it would be great if your answer doesn't need a very deep background in physics or math.

$\displaystyle\sum_{n=1}^\infty \frac{1}{n^s}$ only converges to $\zeta(s)$ if $\text{Re}(s) > 1$.  Why should analytically continuing to $\zeta(-1)$ give the right answer?


I want to install R Studio based on  but I got stuck at part sudo gdebi –n rstudio-0.99.896-amd64.deb and it says gdebi error, file not found: –n I m using Ubuntu 18.04.3 LTS

How do I install a .deb file via the command line?


There are a lot of people like this. They tell you to do something, you say OK and you're going to do it (in a short time like 10 minutes or so), but if they see that you are not doing immediately what they told you, they will continuously tell you "do it", "do it", "do it". Like, every 10 seconds, they tell you to do it and annoy you so much so you do it. Is there a word or phrase to express that in English? I only want to know a phrase for telling again and again continuously. Example: My uncle told me to bring him tea while I was reading a book. I was in the middle of a paragraph when he told me that. I told him "OK, bringing". Then I continued reading, just wanted to finish the paragraph, my uncle says again "bring the tea". And he continued to say that after every 10 seconds. I had not finished the paragraph and he said that so many times that he made me stop reading and bring him tea. Is there a word or phrase for that?

What is the word for act of "demanding for something (many be a toy) repeatedly along with a monotonous sound (not very loudly and not crying)"?  I guess 'whine', 'whimper', or, 'solicit' would not be applicable.  Is that 'nagging'?


Hi guys I am working with this and I am trying to prove to myself that n by n matrices of the type zero on the diagonal and 1 everywhere else are invertible.  I ran some cases and looked at the determinant and came to the conclusion that we can easily find the determinant by using the following $\det(A)=(-1)^{n+1}(n-1)$. To prove this I do induction  n=2 we have the $A=\begin{bmatrix} 0 & 1\\  1 & 0 \end{bmatrix}$ $\det(A)=-1$ and my formula gives me the same thing (-1)(2-1)=-1  Now assume if for $n \times n$ and $\det(A)=(-1)^{n+1}(n-1)$  Now to show for  a matrix B of size $n+1 \times n+1$. I am not sure I was thinking to take the determinant of the $n \times n$ minors but I am maybe someone can help me. Also is there an easier way to see this is invertible other than the determinant? I am curious.

Let  $$A_2 = \left[ \begin{array}{cc} 0 & 1\\ 1 & 0 \end{array}\right]$$  $$A_3 = \left[ \begin{array}{ccc} 0 & 1 & 1\\ 1 & 0 & 1 \\ 1 & 1 & 0 \end{array}\right]$$  $$A_4 = \left[ \begin{array}{cccc} 0 & 1 & 1 & 1\\ 1 & 0 & 1 & 1 \\ 1 & 1 & 0 & 1 \\ 1 & 1 & 1 & 0\end{array}\right]$$  and so on for $A_n$.  I was asked to calculate the determinant for $A_1, A_2, A_3, A_4$ and then guess about the determinant for $A_n$ in general. Of course the pattern is clear that  $$ \det A_n = (n-1)(-1)^{n-1} $$  but I was wondering as to what the proof of this is. I tried to be clever with cofactor expansions but I couldn't get anywhere.  Could someone explain it to me please?


What is the purpose of chains hanging from the book shelves of libraries in the Citadel and Castle Black in Game of Thrones?

Question  Since the Citadel gets decent screen time the first two episodes this season I happened to notice and wonder about the chains tangling from certain book shelves.  What is the purpose of those chains?  Research findings  I came across an explanation , that says that similar chains served as some ancient version of an anti-theft device. But there are some points that leave me thinking:   The Citadel library already has dedicated departments for valuable books.  The books do not show any obvious fittings to connect chains to. As far as I know the Citadel library is not a public library, thus reducing the pool of suspects.   Screenshot


I'm going to install 64 bit 14.04 on a new machine with something like 1 to maybe 128GB RAM and even more RAM later. How much space should I allocate to the swap partition?   And especially: WHY those recommendations for these numbers?    (None of the existing answers  and  explain any of the why and are a bit dated if we look at 1GB or RAM and up)

I wanted to just confirm how much the size of Swap partition should be. Lots of places tell that the swap size should be twice the size of RAM. Somebody also told me that it shouldn't be more than 8 GB.If twice the size of RAM is more than 8 GB how big should the Swap partition be?


If I have a transmitter that signals a relay which turns off a light off which is 300 000 km away – it has travelled at the speed of light.  If I connected a rope (which does not stretch) which is connected to this same light bulb and we ignore the weight of the rope and the friction of dragging it. Have I not completed an action which is 300 000 km in a second?  If this same light is 600 000 km away and I connect a rope twice as long and pull it to shut off this same light bulb it has completed an action twice the distance and will beat the transmitter signal. Is this not faster than the speed of light?  How does time dialation affect this rope? Is this not instantaneous like quantum entanglement?   If I have a wheel that has a 300 000 km diameter, and I spin the wheel at the speed of light.  I then put rocker switches to turn the light bulb on or off to represent 0 and 1. Have I not communicated binary code at the faster than the speed of light.  What if I then mesh this wheel with a wheel that has twice the circumference to turn the wheel even faster?    What if I then put flashlight on this wheel 180 degrees apart and spin this same wheel at the speed of light what is the projection of this light as it travels through space.

Is it possible for information (like 1 and 0s) to be transmitted faster than light?   For instance, take a rigid pole of several AU in length. Now say you have a person on each end, and one of them starts pulling and pushing on his/her end.   The person on the opposite end should receive the pushes and pulls instantaneously as no particle is making the full journey.  Would this actually work?


i have a quick question.  We have a machine which has a camera mounted above a board at 75cm. The cameras ability to focus on an object at 0 zoom is 1cm, and all full zoom 120cm. The zoom is build into the camera and i have no idea what optic is on the camera at the moment. To reduce the focal length of the camera at full zoom we use an optic, this enables the camera to focus correctly whist fully zoomed in dispite it only being 75cm away form the camera(not 120cm). This optic is very very expensive however,   It works fine but i'm not sure we need this, is there way to firstly determine what optic is on the camera by the focal lengths given? and secondly what optic would need to be mounted on front of the camera in order to make the focal length at full zoom 75cm, as i can't take out the optic in the camera all ready i would like something to add to it to make up for the shortfall.   Sorry i'm a programmer and i have to get this camera focusing properly, my knowledge of physics is not great so apology's in advance for what is surely a poorly worded question  UPDATE  Sorry guys the camera im using in a Sony FCB-6500   I have also attached an image from the camera, its a grossing station however as you see there is the need to zoom in and study small object in great detail, at the moment tho the focus is no working so its blurry     Thanks Again

Here is my problem, I Have a scientific camera, a , which has an automatic focus. The minimum focus distance is 1 cm when completely zoomed out and 120 cm when fully zoomed in. I'm not sure what lens is in the camera but I was hoping someone could tell me what optics I would need to add to the camera to make it auto-focus at maximum zoom to a distance of 75 cm.   Thanks in advance.


I have a Dell Inspiron 13 5378 and I have now been using Ubuntu for roughly a month.  I use the terminal a lot and my password is fairly long (28 characters).  What I have noticed is that when I enter my password into the terminal and I mess up and I know I messed up, the terminal takes longer to process the password than if it was typed incorrectly.  At first, I thought that the kernel stored my passwords in memory and this was a major security issue but then I noticed this also happens when I have just opened it up and I need to sign in so that can't be it, right?  Why does this happen and is this a security issue?

When entering the right password the application or the OS (no specific application, pretty much everywhere) accepts this immediately, but when entering a wrong password there is a slight delay of 1-2 seconds. Why is that?


This might sound like a very simple question, but I haven't been able to find an answer to it, yet:  Assuming I am working on a binary classification task and I am using k-fold cross-validation to train classifiers on a train/test split of my data: After running CV I would end up with k trained classifiers. Which one of these would I actually use to classify new data? Would I simply meassure F1 etc. and use the best one? Or should I use some kind of ensemble method and use all k in some kind of voting?

I am wondering how to choose a predictive model after doing K-fold cross-validation.   This may be awkwardly phrased, so let me explain in more detail: whenever I run K-fold cross-validation, I use K subsets of the training data, and end up with K different models.   I would like to know how to pick one of the K models, so that I can present it to someone and say "this is the best model that we can produce."   Is it OK to pick any one of the K models? Or is there some kind of best practice that is involved, such as picking the model that achieves the median test error?


I have a VF page tied to a controller which utilizes "StandardSetController" to retrieve the list of views created. The problem is whenever I am trying to get those list views using getListViewOptions() on runtime, it only returns one list view which is "All". When executed independently (through console), the same code works just as expected.  Here is some snippet of my code:  VF page  <apex:selectList value="{!filterId}" size="1"> <apex:actionSupport event="onchange"     rerender="mpb,commandLinksPagination" action="{!resetFilter}"     status="idStatus" /> <apex:selectOptions value="{!listViewOptions}" />     Controller  public ApexPages.StandardSetController con {     get {          if(con == null) {             List<EUR_CRM_Account__c> accList = new List<EUR_CRM_Account__c>();              con = new ApexPages.StandardSetController(Database.getQueryLocator(                 'select name, EUR_CRM_Group_Outlet_Type__c, EUR_CRM_Outlet_Type__c,EUR_CRM_Outlet_Type__r.EUR_CRM_name__c,  EUR_CRM_City__c ,EUR_CRM_Image_Level_Name__c ,EUR_CRM_Group_Outlet_Type_Name__c ' +                 ', EUR_CRM_No_of_Active_Contracts__c, ownerid, owner.name, recordTypeId, EUR_CRM_Company_Establishment__c '  +                  'from EUR_CRM_Account__c LIMIT 1'             ));                               System.debug(con.getListViewOptions()); // "All" is printed              if(filterId != null) {                  this.con.setPageSize(pSize);                 con.setFilterId(filterId);                 this.euAccounts = null;                 this.selectedAccounts = new Set<Id>();             }         }          return con;     }     set; }  public SelectOption[] getListViewOptions() {     List<SelectOption> selOpList = new List<SelectOption>();     selOpList.add(new SelectOption('', '--None--'));     selOpList.addAll(con.getListViewOptions());      return selOpList; }   Any feedback/guidance is much appreciated!

I have a page where I am trying to show which ListViews a Project is in. I can get the data I want in the Developer Console by querying ListView. However, when I try to import the following query to my code I get the following exception: "Save error: sObject type 'ListView' is not supported." Query:  SELECT Id, Name FROM ListView WHERE SObjectType = 'Project__c'   As a workaround, I am trying to instantiate an Apex:StandardSetController for Project__c and call getListViewOptions(). Notice I am not calling getListViewOptions on my ApexPages.StandardController. The relevant bit that is not working:  public MyExtension(ApexPages.StandardController notUsed) {     debugListViews(); // yields bogus results } public MyExtension(ApexPages.StandardSetController notUsed) {     debugListViews(); // yields valid results } private void debugListViews() {     ApexPages.StandardSetController controller = new ApexPages.StandardSetController([         SELECT Id FROM Project__c LIMIT 1     ]);     for (SelectOption option : controller.getListViewOptions())     {         system.debug(option);     } }   This code works perfectly in Execute Anonymous. I see a list of SelectOption each of which has a valid Name/Id combination. However, when I run this code in my extension's constructor that takes in an ApexPages.StandardController, I get only one SelectOption that is clearly bogus. The Name is "All" and the Id is "000000000000000AAA". Note: the key prefix for ListView is "00B."  To add to the mystery, this code also works as expected in my extension constructor that takes in an ApexPages.StandardSetController.  This seems like it is a Salesforce bug, but I am not allowed to submit a Development Case for this org. Has anyone run into this before and found a workaround?


I have a trajectory and a map that I have divided in segments. I want to locate each point (using for its id its time-stamp) to the appropriate segment, using qgis. How can I accomplish this?

I have gridded depth points in CSV format that I'm trying to add other map data to, in additional columns. I've tried joining fields, hoping that I could link the Shapefile data to the csv, but when I try to display the csv by graduated symbols based on the new fields, it goes blank. I used Nathan's tips from , but imported the csv as csv since I want to add map info to that, rather than adding csv info to a map.  See this picture below for the sea bottom temperature & salinity voronois by month, underneath the csv points (a sample subset), with the joins already made. I added columns on the csv for each of the fields i'm intending to append.    I also tried spatial joins as per  however it says the layers aren't the same CRS (I checked, they are), then gets to 15% and hangs.  I also also tried spatial join through  but it hit a python error. I can try this again and look to debug the problem if this is the right way to go.  In short: appending polygon data as fields on a points-grid csv: what's the best way in QGIS 2.0?


dpkg: aviso: cups-browsed: não foi possível abrir /usr/lib/cups/backend/implicitclass para o hash: Permission denied  ??5??????   /usr/lib/cups/backend/implicitclass ??5??????   /boot/vmlinuz-5.8.0-31-generic dpkg: aviso: geoclue-2.0: não foi possível abrir /var/lib/polkit-1/localauthority/10-vendor.d/geoclue-2.0.pkla para o hash: Permission denied  ??5??????   /var/lib/polkit-1/localauthority/10-vendor.d/geoclue-2.0.pkla dpkg: aviso: systemd: não foi possível abrir /var/lib/polkit-1/localauthority/10-vendor.d/systemd-networkd.pkla para o hash: Permission denied ??5??????   /var/lib/polkit-1/localauthority/10-vendor.d/systemd-networkd.pkla dpkg: aviso: network-manager: não foi possível abrir /var/lib/polkit-1/localauthority/10-vendor.d/org.freedesktop.NetworkManager.pkla para o hash: Permission denied ??5??????   /var/lib/polkit-1/localauthority/10-vendor.d/org.freedesktop.NetworkManager.pkla dpkg: aviso: linux-modules-5.8.0-33-generic: não foi possível abrir /boot/System.map-5.8.0-33-generic para o hash: Permission denied ??5??????   /boot/System.map-5.8.0-33-generic dpkg: aviso: linux-image-5.8.0-33-generic: não foi possível abrir /boot/vmlinuz-5.8.0-33-generic para o hash: Permission denied ??5??????   /boot/vmlinuz-5.8.0-33-generic dpkg: aviso: sudo: não foi possível abrir /etc/sudoers para o hash: Permission denied ??5?????? c /etc/sudoers dpkg: aviso: sudo: não foi possível abrir /etc/sudoers.d/README para o hash: Permission denied ??5?????? c /etc/sudoers.d/README dpkg: aviso: ppp: não foi possível abrir /etc/chatscripts/gprs para o hash: Permission denied ??5?????? c /etc/chatscripts/gprs dpkg: aviso: ppp: não foi possível abrir /etc/chatscripts/pap para o hash: Permission denied ??5?????? c /etc/chatscripts/pap dpkg: aviso: gnome-initial-setup: não foi possível abrir /var/lib/polkit-1/localauthority/10-vendor.d/gnome-initial-setup.pkla para o hash: Permission denied ??5??????   /var/lib/polkit-1/localauthority/10-vendor.d/gnome-initial-setup.pkla dpkg: aviso: linux-modules-5.8.0-31-generic: não foi possível abrir /boot/System.map-5.8.0-31-generic para o hash: Permission denied ??5??????   /boot/System.map-5.8.0-31-generic dpkg: aviso: packagekit: não foi possível abrir /var/lib/polkit-1/localauthority/10-vendor.d/org.freedesktop.packagekit.pkla para o hash: Permission denied ??5??????   /var/lib/polkit-1/localauthority/10-vendor.d/org.freedesktop.packagekit.pkla dpkg: aviso: cups-filters: não foi possível abrir /usr/lib/cups/backend/cups-brf para o hash: Permission denied ??5??????   /usr/lib/cups/backend/cups-brf dpkg: aviso: policykit-desktop-privileges: não foi possível abrir /var/lib/polkit-1/localauthority/10-vendor.d/com.ubuntu.desktop.pkla para o hash: Permission denied ??5??????   /var/lib/polkit-1/localauthority/10-vendor.d/com.ubuntu.desktop.pkla dpkg: aviso: fwupd: não foi possível abrir /var/lib/polkit-1/localauthority/10-vendor.d/fwupd.pkla para o hash: Permission denied ??5??????   /var/lib/polkit-1/localauthority/10-vendor.d/fwupd.pkla  Should I ignore since it's not affecting my machine performance or try to dig it out? ~$ sudo dpkg --verify   ??5??????   /boot/vmlinuz-5.8.0-31-generic

I ran DPKG Verify on all packges and got this output and I don't know what it means :  ??5?????? c /etc/lightdm/lightdm-gtk-greeter.conf ??5?????? c /etc/default/chromium-browser ??5??????   /usr/local/etc/no-ip2.conf ??5??????   /var/lib/dokuwiki/data/cache/_dummy ??5?????? c /etc/xdg/menus/mate-settings.menu ??5?????? c /etc/apache2/apache2.conf ??5?????? c /etc/apt/apt.conf.d/10periodic ??5?????? c /etc/sysctl.conf ??5??????   /var/lib/xine/xine.desktop ??5??????   /boot/vmlinuz-4.4.0-21-generic ??5??????   /usr/lib/python3/dist-packages/cupshelpers/__pycache__/cupshelpers.cpython-35.pyc ??5??????   /usr/lib/python3/dist-packages/cupshelpers/__pycache__/xmldriverprefs.cpython-35.pyc ??5??????   /usr/lib/python3/dist-packages/cupshelpers/__pycache__/config.cpython-35.pyc ??5??????   /usr/lib/python3/dist-packages/cupshelpers/__pycache__/openprinting.cpython-35.pyc ??5??????   /usr/lib/python3/dist-packages/cupshelpers/__pycache__/__init__.cpython-35.pyc ??5??????   /usr/lib/python3/dist-packages/cupshelpers/__pycache__/ppds.cpython-35.pyc ??5??????   /usr/lib/python3/dist-packages/cupshelpers/__pycache__/installdriver.cpython-35.pyc ??5?????? c /etc/xdg/autostart/mate-volume-control-applet.desktop ??5?????? c /etc/libvirt/qemu/networks/default.xml


I don't wish to open terminal each time to execute my shell script. Is it possible assign a keyboard shortcut to execute the shell script I have created?

I want Ctrl+Alt+B bring up a browser.  Ctrl+Alt+Delete is handy.  Can I set up Ctrl+Alt+B to bring up a browser (either default or specific)?


I need to prove the following statement. Let $X$ be a non negative martingale such that $X_n\rightarrow 0$ a.s. when $n\rightarrow \infty$. Define $X^*=supX_n$. Prove that for all $x>0$ $$P[X^*  \geq x | \mathcal{F}_0]= 1 \wedge X_0 / x$$ I think I've got the easy case  if  $x\leq X_0$  Then necessarily $x\leq X^*$ for the sup property. Then it follows that for $1\leq X_0 /x$ we have that $P[X^*  \geq x | \mathcal{F}_0]= 1$. But I can't figure out the other case.

Let $M$ be a positive, continuous martingale that converges a.s. to zero as $t$ tends to infinity. I now want to prove that for every $x>0$ $$ P\left( \sup_{t \geq 0 } M_t > x \mid \mathcal{F}_0 \right) = 1 \wedge \frac{M_0}{x}. $$ My approach: I thought that rewriting the conditional probability to an expectation would help so we obtain that we must prove: $$ \mathbb{E} \left[ 1_{\sup_{t \geq 0 } M_t > x}  \mid \mathcal{F}_0 \right] = 1 \wedge \frac{M_0}{x}.$$ A hint to me was given that I should consider stopping the process when it gets above $x$. Thus a stopping time that would do this is $\tau = \inf\{t\geq 0 : M_t>x\}$. But now I'm stuck as I want to apply optional sampling results but we have an indicator which complicates things. How could I proceed from this? Any help is appreciated!


I am using blender 2.78 and am trying to make a Minecraft animation. When i try to render it, it turns out like this.  Settings:  In cycles render CPU 20 Samples rendering final

I know that this question is a bit old or maybe overdone, but I'm running the latest edition of Blender and when I use the Cycles engine I get really fuzzy results and I can't find a simple, non-compromising solution to the quality.  I don't know exactly what I'm doing wrong here, but I'm sure others share my frustration.  Leaving everything in default settings, I started a new project and switched to the Cycles render.  I duplicated the cube and set colors for two Diffuse BSDF shaders, then went ahead and made walls and a floor all sharing the same diffuse shader.  I made two windows to emit blue light.  The screenshot has gaps between the walls because of the setup:  I'm aware that it's considered very incomplete and many have come to terms with some amount of noise, but is this normal?  Furthermore, with default settings or not, I can't change the amount of noise produced.  Supposedly, using "progressively refine" in the rendering tab should make it refine itself indefinitely, however Cycles only counts to 10 refines and then stops, creating a render which is a pixel-perfect match of the ordinary rendering method when it's completed.  I understand that there are tricks that can be used to reduce noise, but at the cost of extra processing time and usually small quality conflicts, like blurring.  My question essentially boils down to is this Cycles' current limit?


Prompted by recent remembrance day celebrations, it seems to me that the term PoWs is inconsistent with pluralization conventions.  Runs Batted In --> RBI Prisoners of War--> PoW (shouldn't this be the plural?)  I read that laser appears to have become a noun unto itself and is thus pluralized as . Is PoWs an accepted noun or is it an oddly pluralized acronym?   Other acronym pluralization questions that don't address PoW(s) directly:

For abbreviations - both acronyms and initialisms - where the last word in the abbreviation is the noun, I'm accustomed to adding an 's' with no apostrophe (e.g. ATMs), as described in the answer to this question:   But how do you pluralize abbreviations where the noun is not the last word? E.g. 'Point of Presence' (POP)  I can see how 'POPs' could read 'Point of Presences', when the intention is 'Points of Presence.'


Hello i have a Xiaomi Mi 8 and i was playing with adb shell servies commands and now it shows "android phone service stop working" and it keeps rebooting.My question is when i flashing stock firmware from xiaomi tool, deletes everything from / (root) directory and installs new one folders/files?I want to check this to make sure if it's hardware or software problem

My HTC Desire S is working fine when I don't put my micro SD card in it (this card was free with the phone). But the phone keeps restarting every few minutes if I keep the memory card in it. By that, I could say that the phone is fine, but the issue can be either with the memory card or the phone not supporting memory card anymore. The phone and memory card worked completely fine for 8 months.  The thing is, if the same memory card is inserted in any other mobile, be it an Android or any other smartphone, that phone will not restart and the data is completely readable too. So, the memory card is fine. When I insert some other memory card on my phone, then my phone does not restart too. So that means the issue is with my phone & that particular memory card combo.    I am ready to uninstall each and every app from my phone, but will that solve my problem? Should I perform the factory reset? Will it solve my issue? What will I lose if will do the factory reset? Like: contacts, SMS, call logs, APN settings, etc. Any free software to backup all these?  But maybe I am going in the wrong direction. Maybe there is some easy way to get the phone and memory card working.


I want to get a file via http using curl. My environment is GCC (Mac OS X). I've created a simple class Shared to use it smth like this:  #include "Shared.h" ... std::string str = Shared::getHTTPFile( "http://google.com" );   When I try to compile it with the following command:  g++ -o test -l curl test.cpp   I get an error message:  Undefined symbols for architecture x86_64: "Shared::curlBuffer", referenced from:  Shared::getHTTPFile(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >) in test-a10048.o  Shared::writer(char*, unsigned long, unsigned long, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >*) in test-a10048.o "Shared::errorBuffer", referenced from:  Shared::getHTTPFile(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >) in test-a10048.o ld: symbol(s) not found for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation)   My code of Shared class is just simple:  #include <string> #include <stdio.h> #include <curl/curl.h>  class Shared {  public:     static char errorBuffer[ CURL_ERROR_SIZE ];     static std::string curlBuffer;     static int writer( char *data, size_t size, size_t nmemb, std::string *buffer ) {         curlBuffer.append( data, size * nmemb );         int result = size * nmemb;         return result;     }      static std::string getHTTPFile( std::string url ) {         CURL *curl = curl_easy_init();         CURLcode result;         if (curl) {             curl_easy_setopt(curl, CURLOPT_ERRORBUFFER, errorBuffer);             curl_easy_setopt(curl, CURLOPT_URL, "http://google.com" );             curl_easy_setopt(curl, CURLOPT_HEADER, 1);             curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, writer );             curl_easy_setopt(curl, CURLOPT_WRITEDATA, &curlBuffer );             result = curl_easy_perform( curl );         }         curl_easy_cleanup(curl);         return 0;     } };   What do I do wrong here?

Can anyone explain why following code won't compile? At least on g++ 4.2.4.  And more interesting, why it will compile when I cast MEMBER to int?  #include <vector>  class Foo {   public:       static const int MEMBER = 1;   };  int main(){       vector<int> v;       v.push_back( Foo::MEMBER );       // undefined reference to `Foo::MEMBER'     v.push_back( (int) Foo::MEMBER ); // OK       return 0; }


So basically I have a bard that I am about to multiclass into a wizard. I’d like to know if it’s possible to not need a grimoire specifically, but be able to say write my spells by writing them on or carving them into my characters lute? Obviously the space on the instrument used to write spells on and challenges of carving the spells would be limiting/possibly difficult, which is a whole other bag of issues I’m not worrying about just yet.  I just want to know if this is at all possible. I’ve read the PHB and it doesn’t seem to say anywhere that you must use a spell book to write your spells in, nor that there’s much difference from writing in a spell book vs say, a piece of wood you carry with you.  However, I could have possibly missed somewhere where it says you cannot. Either way any help or insight given is much appreciated, thank you.

In the PHB under The Book's Appearance the text give two examples of how a spellbook looks like a book and one example with it being just a collection of notes.  Does a Wizard's spellbook need to be a book? Can a spellbook look or even be something else rather than just a book?  For example, could it be a series of small scroll tubes tied together like a rope ladder?  A necklace of marbles where each marble was inscribed with a single spell?  Elaborate wood carvings on a puzzle-box?  Colourful tattoos on the backs of slaves? (I'm not saying it won't be awkward when a Dragon eats pages 21 to 34 when adventuring, just asking if it would be allowed.)  Runes on the faces of convex regular icosahedron? ;)


I have read this question:    Now analogously, we could talk about GWs traveling in the empty voids of space, where the expansion of space is dominant.  There is a debate over whether gravitons exist or not, and whether gravitons are the quanta of GWs or not, by let's assume yes.  Just as EM waves wavelength get stretched as they travel in expanding space, GWs wavelength could get stretched.  We are actually able to measure the redshifting of EM waves from far away sources.  We could be able to measure the redshifting of GWs from far away sources as we have already detected GWs.   Question:   Can expanding space stretch the wavelength of GWs? When we detected the first GWs, did we measure the actual amount of redshift they went through as they traveled from the source?

Whenever the Doppler effect is mentioned, it's typically in the context of sound waves or electromagnetic radiation. On the cosmological scale, red-shifting is also important because of the enormous speed of receding galaxies, thanks to the expansion of the universe.   Yet, red-shift is always discussed as the red-shifting of electromagnetic waves. Can gravitational waves be red-shifted? If so, could observations of them be used like red-shifted electromagnetic waves from distant sources are; that is, to figure out how fast an object is receding?


The question is "Is the applicant eligible for the Non-ECR category?"  I'm renewing mine and my sister's passport and right now I'm studying for a diploma (2nd year). My sister is in 10th standard right now.

I'm applying for a fresh Passport from India but I don't know what "ECR" & "NON-ECR" mean:     "Is applicant eligible for Non-ECR category?"      [Yes] [No]   I've already Graduated from University. I don't know whether to choose "YES" or "NO"?. I'm Indian by birth.


I would like to compare variances of two independent samples (of different sizes) from two unknown distributions. It seems I should use a one-sided nonparametric test.  Bartlett's and Fligner's tests are two-sided, am I right? What test in R could I use to determine which sample has greater variance?  For example, consider two samples:  x <- c(1,2,3,4,5,6,7,8,9,10) y <- c(10,2,3,4,5,6,7,8,9,100,200,56)

F-tests can be two-tailed (to test that $s_1^2 \ne s_2^2$) or one-tailed (to test that $s_1^2 > s_2^2$).  How can I modify Levene/Brown-Forsythe to be "one-tailed", that is, to test $s_1^2 > s_2^2$ instead of $s_1^2 \ne s_2^2$?  Here is a demo:    The image shows normally distributed training data (n=1000) and a model. An F-test is used to compare the variance of one point's residuals (n=2) to the variance of all of the residuals (n=2000), so the point is an outlier if its residual variance is "too large." The points are colored by p-value, where light points fit the model and dark points are outliers, and you can see that the two-tailed Brown-Forsythe rejects points that are too close to the model as well as too far.  Note: A different non-parametric, one-sided variance test would be fine as well.    Glen_b gave the information I needed, but I thought I would leave some implementation details (using scipy).  #basic F-test F = var(a) / var(b) Fp = stats.f.sf(F, df1, df2)  #Brown Forsythe BF, BFp = stats.levene(a, b, center='median')  #two tailed t-test on transformed data za = abs(a-median(a)) zb = abs(b-median(b)) t, tp_two_tailed = stats.ttest_ind(za, zb)  #the two tailed t test recapitulates the BF test assert(t**2 == BF) assert(p_BF == p_two_tailed)  #one tailed t test p value tp = stats.t.sf(t, df)     Above shows scatter plots of the p values from the one-tailed $F$-test and two-tailed BF-test (left), and the one-tailed $t$ tests (right). Red points are "too close" ($s_1^2 < s_2^2$).


There is a bug where I see a privacy error on all meta.foo.stackexchange.com sites. For example, if I try to enter meta.retrocomputing.stackexchange.com into my browser, I get this warning:  Can someone check this out?

Visiting  displays an HTTPS certificate error in Google Chrome and Internet Explorer 10.  For reference, meta.<sitename>.stackexchange.com is the old URL for per-site metas. Child metas were migrated to <sitename>.meta.stackexchange.com during the implementation of . The old URLs were configured to silently redirect users to the correct page.  This issue has technically been reported a few times before, (, , , , ). However, these reports were made before HTTPS support for child metas was officially completed in .


I had two installations of PHP, PHP5.6 and PHP7.0, working as PHP-FPM/PHP_CGI packages in Ubuntu 14.04 with Apache2. I installed 16.04 thinking that it would not interfere with the third-party (ie: non-linux, non-ubuntu) software installations already in place, but I was obviously very much mistaken in that assumption. It seems that my PHP 5.6 installation was purposefully targeted by the installation and "nullified", but why? Security fixes will be made to PHP 5.6 until the end of 2018!  Why break all the work that I did in setting that up?  All the other posts that I have seen seem to want me to have PHP5.6 or the default PHP 7.0 on my server, but not both. Is there anyway I can have both installations working in 16.04, or do I have to (and can I) revert back to 14.04?  Thanks to anyone who can help.

I am trying to update to install PHP 5.5, 5.6 or 7.0 in Ubuntu 12.04/14.04/16.04 LTS, and I can only get PHP 5.3.10 for Ubuntu 12.04, PHP 5.5.9 for Ubuntu 14.04 or PHP 7.0.4 for Ubuntu 16.04 using official repositories (using apt-get).  I'm not really sure how to do a manual update – as I need:   to play around with the new(est) PHP features to install older PHP version due support in the software


As an Example, I want to refer to this  where there are many conditional sentences. Some of them drop the "then", some of them use it. When I change that (drop it where it was used or add it where it was dropped) then some still sound correct, but some sound a little odd, though all of them are still grammatically correct.  Originals:     If you heat water to 100 degrees, it boils. If the sea is stormy, the waves are high. If it's raining here now, then it was raining on the West Coast this morning. If it's raining now, then your laundry is getting wet. If it's raining now, there will be mushrooms to be picked next week. If he locked the door, then Kitty is trapped inside.   Changed:     If you heat water to 100 degrees, then it boils. If the sea is stormy, then the waves are high. If it's raining here now, it was raining on the West Coast this morning. If it's raining now, your laundry is getting wet. If it's raining now, then there will be mushrooms to be picked next week. If he locked the door, Kitty is trapped inside.   Questions:    Is there a term for dropping "then" in conditional sentences? Are there any guidelines on when it can be dropped and when it must be retained?   EDIT: There is an existing question (  ) but that is more of an "YES/NO" type of question and it has been answered with "YES". Here, the question "When" in terms of guidelines : When it is useful to drop ; When it is useful to retain.

I have the following sentence:     If T had still been alive, there is the great possibility that either T or C ...   My teacher says that the word "then" must appear after the comma, but I think that it's implied and unnecessary. Who is right?


Here is a sample of what I've seen every so often for the last few days on Stack Overflow:    As you can see, the first three questions were recent — 1 and 4 minutes ago (though slightly less when I first loaded the page), but the fourth question was last modified 2 hours ago, then 6 minutes, then 4 hours ago, then 8 and 9 minutes ago.  Is this interweaving of 'old' questions with 'new' questions in the 'home' page intentional? (I am looking at the basic  page.)  What is the rationale behind the revised ordering?  (I did look at the  page and didn't see anything that looked relevant.)    About 4+ hours later:    Two of the questions in the older image are stuck in the newer image.

For nearly 5-6 hours now, I am not getting the usual sorted list of questions on  page. Here are two screenshot(with awesome red-circles)(which are becoming more common in my questions :():      As it can be noticed, all the timestamps are placed randomly. Is it newest feature/change in SO? If so, please revert it. :/ Or is it one of the two options mentioned in the question title?


There is an already defined math operator inside TeX that I want to change it by another letter. I am just wondering what is the best practice. Below I give an example for the \Pr -> "Pr" command to transform \Pr -> "P".  \documentclass{article}  \usepackage{mathtools}     \renewcommand*{\Pr}{\operatorname{P}} % is this the correct form?  %\DeclareMathOperator{\Pr}{P} % any renew equivalent to this definition? %\def\Pr{\qopname\relax m{P}} % like it is defined inside 'amsopn' package  \begin{document}      $\Pr (\gamma \leq \Gamma_{min}) = F_\gamma (\Gamma_{min})$  \end{document}

I'd like to declare some new operators using \DeclareMathOperator and some of the names are already taken by other commands (that I do not want to use). Is there an equivalent to the \renewcommand command for \DeclareMathOperator or a different way to overwrite the commands using \DeclareMathOperator?


Does the expansion of the universe have an effect on the laws of physics, or the constants used in physics? If we were to imagine the universe 40 billion years later, would the same laws still apply?

Hubble's constant $a(t)$ appears to be changing over time. The fine stucture constant $\alpha$, like many others in QFT, is a running constant that varies, proportional to energy being used to measure it. Therefore, it could be agued that all running constants have 'evolved' over time as the Universe has expanded and cooled. Both the local and global curvature of the Universe changes over time implying that so too does the numerical value of $\pi$. All these things are however constants (well, let's say parameters since they are not really 'constant'.)   In  with astronomer Sir Fred Hoyle, Feynman said "what today, do we not consider to be part of physics, that may ultimately become part of physics?" He then goes on to say "..it's interesting that in many other sciences there's a historical question, like in geology - the question how did the Earth evolve into the present condition? In biology - how did the various species evolve to get to be the way they are? But the one field that hasn't admitted any evolutionary question - is physics."  So have the laws of physics remained form-invariant over the liftetime of the Universe? Does the recent understanding of the aforementioned not-so-constant constants somehow filter into the actual form of the equations being used? Has advances in astronomical observations, enabling us to peer back in time as far back as the CMB, given us any evidence to suggest that the laws of nature have evolved? If Feynman thinks that "It might turn out that they're not the same all the time and that there is a historical, evolutionary question." then this is surely a question worth asking.  NB/ To be clear: this is a question concerning purely physics, whether the equations therein change as the Universe ages, and whether there is any observational evidence for this. It is not intended as an oportunity for a philosophical discussion.


I've a simple code as below and it returns false when I have a space after "N/A" string.  String a = "N/A "; if((a.trim())=="N/A") {  System.out.println("true"); } else{  System.out.println("false"); }   if I remove the space as "N/A" then it returns true. What am I missing here. I know I'm making a silly mistake couldn't figure it out.  Thanks in advance.

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


public class DictionaryBase<T extends IData> {     protected Map<String, T> mdic = new HashMap<>();      protected T Add(String Name) {         T objNew = new T();          objNew.Name(Name);         mdic.put(Name, objNew);          return objNew;     }   On new T() I have the Error. What is the correct way to do this?

I have got a template class as follows:  class MyClass<T> {     T field;     public void myMethod()     {        field = new T(); // gives compiler error     } }   How do I create a new instance of T in my class?


The site tour uses an example question to illustrate how sites work.  By default, it is a question about preventing unicorns from eating daisies.  I know that it's possible to change that question (some sites have done so) and that there are some pretty strict requirements on candidate questions in order to be used for that.  (On one site where I'm a moderator, following the "edit question" link just leads to a message saying "no eligible questions".)  I believe there is a length limit and that certain formatting is not allowed.  I've searched MSE and checked the moderator-only section of the help center but I can't find the specific requirements.  What are they?  If my site wants to change the tour question, what conditions must our proposed replacement satisfy?

Diamond moderators  . In the second section from the top—entitled "Ask questions, get answers, no distractions"—that takes us to an opportunity to select one of a page full of questions from the site as the example question used on the about page. The selections currently available on physics are a little idiosyncratic. Is there some rhyme or reason to these? I suppose that we want a good example question to:  Be accessible to the intended audience (perhaps even to the newest and most naive person in that audience) Be judged at least decent by the community (positive score) Have more than one answer which are also judged acceptable (again positive score)  What else? How does a question end up on the list?


I am trying to solve this question.  Let $F$ be a point set in $\mathbb R^d$ of size $n$. Prove that it is possible to denote the points of $F$ as $X_1,\dots, X_n$ in such way that, for any $i\in \{2,\dots, n-1\}$, the angle $\angle X_{i-1}X_iX_{i+1}$ is acute.  I think I have to use permutation for this but I am unable to relate to it. Thanks in advance.

Let $x_1, \ldots ,x_n$ be distinct points in $\Bbb{R}^d$. Prove that there is a permutation $\sigma$ of $[n]$ such that the $\angle x_{\sigma(i−1)}x_{\sigma(i)}x_{\sigma(i+1)} < \pi/2$ for any $i = 2,\ldots, n−1$.  So I have got this question, and I am not able to understand what "a permutation $\sigma$ of $[n]$" mean? Can someone explain to me this question and provide some hints to approach it? P.S. I have edited out some parts as it was a bit irrelevant.


What explanation is given under A. Newtonian gravity and B. General relativity for the fact that in the absence of atmospheric influences, bodies of different mass fall at equal rates. It's so counterintuative and I can't seem to locate an answer!

I'm far from being a physics expert and figured this would be a good place to ask a beginner question that has been confusing me for some time.  According to Galileo, two bodies of different masses, dropped from the same height, will touch the floor at the same time in the absence of air resistance.  BUT Newton's second law states that $a = F/m$, with $a$ the acceleration of a particle, $m$ its mass and $F$ the sum of forces applied to it.  I understand that acceleration represents a variation of velocity and velocity represents a variation of position. I don't comprehend why the mass, which is seemingly affecting the acceleration, does not affect the "time of impact".  Can someone explain this to me? I feel pretty dumb right now :)


I know that given $B$, a compact subset of $\mathbb{R}^n$, and $f : B \to \mathbb{R}^m$, a continuous injective (one-to-one) function, $f^{-1}$ is continuous on $f(B)$. (This true).  I also know that image $f(X)$ of a connected subset $X$ is connected under a continuous function.  Now let $X$ be a connected (non-compact) subset of $\mathbb{R}^n$, and $f : X \to \mathbb{R}^m$ be a continuous injective (one-to-one) function. I am trying (and struggling) to provide a counterexample in which mapping $f^{-1} : f(X) \mapsto X$ is not continuous on $f(X)$. (A rigorous, parametrized example).  Thank you in advance!

What are some examples of functions which are continuous, but whose inverse is not continuous?  nb: I changed the question after a few comments, so some of the below no longer make sense. Sorry.


The only thing that I want is a numbering out of colored box and the position of box be in center.  \documentclass{article} \usepackage{amsmath,amsthm,amssymb,amsfonts} \usepackage{tcolorbox} \usepackage{tikz} \tikzstyle{mybox} = [draw=green!70, fill=green!10, very thick, rectangle, rounded corners, inner sep=10pt, inner ysep=20pt] \tikzstyle{fancytitle} =[fill=blue!70, text=white] \begin{document} \begin{tikzpicture} \node[mybox](box){%     \begin{minipage}{0.9\textwidth} \begin{equation} L y=b  \quad \quad Ux=y \end{equation}     \end{minipage} }; \end{tikzpicture}%  \end{document}

I want numbered the third (blue) equation in out of box. what do I do?


I want to set up an account purely for someone/thing to access via SFTP.  I have already setup the home directory as /media/HardDrive/FTP  Is there any way to prevent this user (Bob) from accessing /media/HardDrive?  Probably a really simple thing to do but I want to lock them out of /media/HardDrive.  I'm still getting to grips with the whole Linux operating system so a step-by-step instruction guide on how to do this would be really helpful as I'm not totally sure what I need to do.

I want to give a client access to my server, but I want to limit those users to their home directories. I will bind-mount in any files I want them to be able to see.  I've created a user called bob and added him to a new group called sftponly. They have a home directory at /home/bob. I've changed their shell to /bin/false to stop SSH logins. Here is their /etc/passwd line:  bob:x:1001:1002::/home/bob:/bin/false   I've also changed the /etc/ssh/sshd_config to include the following:  Match Group sftponly         ChrootDirectory /home/%u         ForceCommand internal-sftp         AllowTcpForwarding no   When I try to log in as them, here's what I see   $ sftp bob@server bob@server's password:  Write failed: Broken pipe Couldn't read packet: Connection reset by peer   If I comment out the ChrootDirectory line I can SFTP in but then they have free rein over the server. I have found that ChrootDirectory /home works, but it still gives them access to any home directory. I have explicitly tried ChrootDirectory /home/bob but that doesn't work either.  What am I doing wrong? How can I limit bob to /home/bob/?  ----EDIT-----  Okay so I just had a look at /var/log/auth.log and saw this:  May  9 14:45:48 nj sshd[5074]: pam_unix(sshd:session): session opened for user bob by (uid=0) May  9 14:45:48 nj sshd[5091]: fatal: bad ownership or modes for chroot directory component "/home/bob/" May  9 14:45:48 nj sshd[5074]: pam_unix(sshd:session): session closed for user bob   I'm not entirely sure what's going on there,  but it suggests something is wrong with the user directory. Here is the ls -h /home output:  drwxr-xr-x 26 oli      oli      4096 2012-01-19 17:19 oli drwxr-xr-x  3 bob      bob      4096 2012-05-09 14:11 bob


: [Heading:] Is this [a duty to give] too demanding? Singer's argument is clear, and when you consider the drowning child example, pretty seductive. But it does impose very high obligations on those of us who live in comparatively rich countries, and it may be just too demanding. ●... It fails to recognise our own intrinsic moral value as persons.  I know no philosophy, so would someone please explain the meaning of the bolded, basically and simply (without cant or abstract parlance)?  How does 'donating' imply the above? Wouldn't bona fide donation confirm and improve our morality?

: Reasons of principle Torture treats the victim as a means to an end and not an end in themselves [First bullet] ● it treats the victim as a 'thing', not as a person with all the value that we associate with persons [I omit the other bullets because I want to understand this sentence only from itself, alone]  I contended against , but now the bold confuses me. Would someone please explain if the bolded depends on the virtues or vices of a victim? Suppose a depraved, heinous person is tortured (I'll abbreviate him as a malfeasant). Wouldn't torture correspond wih the negative values of this malfeasant, and thus this malfeasant him/herself? Is it possible that society may judge that a malfeasant not require  (last clause, para 4)? Then how does the bolded make sense? I know no philosophy, so would someone please explain the meaning of the bolded, basically and simply. Also, please recognise that I'm only trying to understand the bolded. This post only hypothesises a situation and neither implies or reflects anything about me or my opinions on torture.


The equation for creating a quaternion from an axis-angle representation is $$x'= x \sin\left(\frac \theta 2\right)$$ $$y' = y \sin\left(\frac \theta 2\right)$$ $$z' = z \sin\left(\frac \theta 2\right)$$ $$w' = \cos\left(\frac \theta 2\right)$$ But why $\frac \theta 2$? Why not just $\theta$?

Something is a little bit unclear to me. In the image below you see that you need to divide the angle by a half.  Acccording to wikipedia they say that this is so that I could rotate clockwise or counter clockwise. The sine function returns a value between 1 and -1. So I don't understand it. Could somebody explain why I need to divide my angle by a half?


In a  of H.R. Pitt's Integration, Measure and Probability, Sir John Kingman wrote,     The author is often careless about details, asserting for instance (on page 105) that a function continuous on the rationals has a continuous extension to the reals.   Using the properties of Cauchy sequences and completeness of $\mathbb R$, I can prove that if $f:\mathbb Q\to\mathbb R$ is uniformly continuous, then there exists a continuous function $g:\mathbb R\to\mathbb R$ such that $f=g$ on $\mathbb Q$.  It follows that any inextensible $f$ cannot be uniformly continuous on $\mathbb Q$. However, I am unable to come up with a concrete example.

Given a continuous function $f:\mathbb{Q}\to\mathbb{Q}$ ,does there exist a continuous function  $g:\mathbb{R}\to\mathbb{R}$ such that   $g|_{\Bbb Q} = f$?  What I have no Idea about how to attempt this Question! Any suggestion will be very helpful.


I have tried many solutions found in aksubuntu, but no luck in getting the wireless to work on this computer. The wired connection works. Below is the wireless information.  01:01.0 Network controller: Broadcom Corporation BCM4318 [AirForce One 54g] 802.11g Wireless LAN Controller (rev 02)      Subsystem: Linksys WMP54GS v1.1 802.11g Wireless-G PCI Adapter with SpeedBooster      Flags: bus master, fast devsel, latency 64, IRQ 22      Memory at feafe000 (32-bit, non-prefetchable) [size=8K]      Kernel driver in use: wl      Kernel modules: wl, ssb   All available updates were downloaded and installed 09/01/13. The b43 cutter and installer were tried and the placing of the '#' in front of the blacklisted bcm43xx has been tried (# bcm43xx). Hardinfo was installed also. I am new to Linux, but I am determined to learn all that I can to get this computer fully functional on this os.

After installing Ubuntu 12.04 LTS on my HP Folio 13 I cannot get wireless to work. My kernel is 3.8.0-29-generic and my wireless module is a Broadcom BCM4313.  After running rfkill list all:  0: hp-wifi: Wireless LAN Soft blocked: no Hard blocked: no 1: hp-bluetooth: Bluetooth Soft blocked: no Hard blocked: no 2: hci0: Bluetooth Soft blocked: no Hard blocked: no   The wired connection works fine. The driver activation for Broadcom STA wireless driver fails every time. in the log it says  FATAL: Module wl not found. FATAL: Error running install command for wl   After running lspci -nnk | grep -iEA3 "(wireless|network|wlan)":  02:00.0 Network controller [0280]: Broadcom Corporation BCM4313 802.11bgn Wireless Network Adapter [14e4:4727] (rev 01) Subsystem: Hewlett-Packard Company Device [103c:1795] Kernel modules: bcma 03:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. RTS5209 PCI Express Card Reader [10ec:5209] (rev 01)   I have also tried this method and it did not work: .


I want to configure the edit widget (in qgis: "Properties" of a layer, "Fields", column "edit widget") for a field of a editable layer (shapefile) using a Python plugin. I want set the edit widget with a "Value Map" using a CSV file for the values.  In the documentation  i find the method setEditorWidgetV2Config, but when i try a code like this:  layToEdit.setEditorWidgetV2Config(indField, {...} )   QGIS returns this error for any configuration value in the second parameter:  (qgis.bin:6585): Gtk-CRITICAL **: IA__gtk_widget_get_direction: assertion 'GTK_IS_WIDGET (widget)' failed   what parameters should I use to configure the edit widget as a "value map" that uses the values of a CSV?

I would like to make by programmation (python) the same thing than we can do directly in QGIS when you create a list of values for a field. I would like to create a new field and specify a list of possible values for this field. I didn't find any function for that in the API. Is there anyone who has the solution?


To apply and visualize PCA in R often ggbiplot() is used. What is the meaning of this plot ? Why  it is useful for PCA ?  We can consider this example:     In particular, what is the meaning of arrows and circle?

Is it possible to visualize the output of Principal Component Analysis in ways that give more insight than just summary tables? Is it possible to do it when the number of observations is large, say ~1e4? And is it possible to do it in R [other environments welcome]?


Is there a continuous bijection from open interval $(0,1)$ to $[0,1]$. The answer is not. How to prove?   I think it may proceed by contradiction and apply open mapping theorem. However, $(0,1)$ is not complete. I get stuck.

Does there exist a continuous bijection from $(0,1)$ to $[0,1]$? Of course the map should not be a proper map.


The appearance/ look of English Language & Usage SE has changed in my mobile phone and it was completely unexpected. It wasn't like this before. I use SE on Chrome in my mobile phone (Android).  It was like how it looks on PC.  Also, lots of options are missing in this version. The old version was way better than this one and had many options.   For example, I'm unable to view history of the post, no options while editing or posting.  How do I revert it? Here's a screenshot of the new version (bluish one).

I seem to have clicked on something that changed my display preferences. The main site is now very minimalistic, with fewer controls and different fonts.  I want to change it back, but where is it?


Let's say there is a question. It was ambiguous. Only for one user it wasn't and he answered. And then question got clarified. It cannot even count as drastic edit. It left answer looking off-topic, low quality. So it's either upvoted by people who knows how the question looked earlier (bad for future readers), or downvoted by ones looking at "now" (bad for honest user who answered). Is there any way to deal with these situations?

I'm not sure if there's already an existing term for this, so I'm inventing my own. (tl;dr: I call them "chameleon questions" because they change every time you submit or edit an answer.  If you're already intimately familiar with the phenomenon, please skip past the first set of bullet points to where I ask for recommendations.)  I think many of us have experienced this on occasion:  You open up a narrow-looking question, usually dealing with some specific error message.  The question probably contains a snippet of sloppy but not quite awful code; code indicating that the author, typically a new/low-rep user, possibly a , doesn't really know what they're doing.  I'm not trying to be condescending here, they're probably very intelligent and hardworking, but in this specific case, they're clearly in way over their head.  However, as a question, it's not really too bad.  The goal and problem are both clearly stated.  The code is formatted (sort of).  Mort was polite and checked their spelling.  The question looks answerable, although from a rep perspective* it's an obvious dead-end, it's had maybe 3 views in the past 30 minutes.  So you decide, you know what, this person took the time to write up the question properly, they deserve an answer, put on your good citizen hat and throw them a bone.  You slog through the ugly code, find the offending line, direct their attention to it and explain why it's wrong and how it needs to be fixed.  Later, they leave a comment saying that yes, that was indeed the problem and your answer helped them fix it (great!).  Oh, but, now there's another problem (uh-oh...). Something else is broken.  After letting out a long sigh, you read the comment and/or edited question, roll up your sleeves, and write up Take 2, hoping that's the end of it.  And of course it's not the end.  Now maybe the error is gone, but it's not doing what it's supposed to.  If you're anything like me, your patience is now starting to wear thin. It's lousy code and you didn't volunteer to help them rewrite their whole app.  And of course, the question still only has 12 views, and nobody has upvoted either the question or your answer, including the person you're helping, so this is turning out to be a genuinely thankless task in all respects.  Welcome to "Family Tech Support", Web 2.0 Edition.   * Which is of course just an arbitrary number that none of us care about. Not really, anyway. Not very much, at least.  So, here's where I get to my question.  At this point, do you:  Leave a comment, stating as politely as possible that you've done your best to help them answer the original question they asked, and if they have a new problem then they should start a new question?  (I did this once, and actually ended up with an accept, but I felt kind of guilty afterwards, I don't think anybody answered their 2nd question).  Bite the bullet and edit your answer a 3rd, 4th, 5th time, however many times it takes to resolve their issue, knowing full well that they may not even remember to accept the answer once you're done? (I may work for free on SO, but that doesn't mean my time is worthless.)  Just abandon the question, hoping that it will force Mort to start thinking for himself?  Something else?   I've tried all three of the above and none of them ever quite feel right. I do want to help, but at the same time there are a lot more "lucrative" questions I could be answering. And I don't mind spending a lot of time on an answer either, if the question is interesting or important to me, but debugging is dull work. I'd prefer not to reference specific questions here; I'm pretty sure that this is a shared experience, and my objective isn't to point fingers at "misbehaving" members.  I'm more looking for some practical advice on how to dig myself out of these pits of despair. Anybody have any other ideas?


I just mended an old laptop, that have a dual boot windows8/linux  I can't remember any password, I decided to use a live ubuntu to hack into windows. Problem is I can't mount windows partition in write mode :  Windows is hibernated, refused to mount. Falling back to read-only mount because the NTFS partition is in an unsafe state. Please resume and shutdown Windows fully (no hibernation or fast restarting.)   I tried to fix this problem using ntfsfix  $ sudo ntfsfix /dev/sdb2 Mounting volume... Windows is hibernated, refused to mount. FAILED Attempting to correct errors...  Processing $MFT and $MFTMirr... Reading $MFT... OK Reading $MFTMirr... OK Comparing $MFTMirr to $MFT... OK Processing of $MFT and $MFTMirr completed successfully. Setting required flags on partition... OK Going to empty the journal ($LogFile)... OK Windows is hibernated, refused to mount. Remount failed: Operation not permitted   It failed as well, I tried adding -o remove_hiberfile when mounting without success either.   How can I boot windows partition in write mode ?

Whenever I boot Ubuntu, I get a message that it cannot mount my windows partition, and I can choose to either wait, skip or manually mount.  When I try to enter my Windows partition through Nautilus I get a message saying that this partition is hibernated and that I need to enter the file system and properly close it, something I have done with no problem so I don't know why this happens.    Here's my partition table, if any more data is needed please let me know.     Device Boot      Start         End      Blocks   Id  System /dev/sda1            2048    20000767     9999360   83  Linux /dev/sda2        20002814   478001151   228999169    5  Extended /dev/sda3   *   478001152   622532607    72265728    7  HPFS/NTFS/exFAT /dev/sda4       622532608   625141759     1304576   82  Linux swap / Solaris /dev/sda5        20002816   478001151   228999168   83  Linux


I am brewing a Black Rock..."Miners Stout" .  and it's been nearly a week in the fermenter with none to very little movement in the airlock. ! Seems odd as to all the other stouts that I have brewed. Would this mean a faulty beer mix ?  the fermenter is sealed as for using vasaline  around the thread and rubber seal...plus the rubber bung and the end of the airlock. Temp; has been at 24c .  (as on a heat pad). OG= 1055. There is a thin line of Krausen around fermenter. Your thoughts would be welcome. From ...Darkest-porter

EDIT: I see from this  and from elsewhere on the Web that a bubbling airlock is apparently not an indicator for fermentation, as there could be a leaky lid. Regardless, doesn't a non-bubbling airlock indicate that something is wrong, as there could be a leaky lid? I'm under the impression we use an airlock in the first place to keep air out as it would oxidize the alcohol into vinegar.   This was my seventh extract batch. For the last 4 batches I've done a yeast starter and aeration with an aeration stone. This has moved my lag time from 24 hours max to 12-16 hours max. For all my other batches I get a vigorous airlock for 4 days. Normally I pitch the yeast in the middle of the fermentation bucket and do NOT stir the yeast around. I normally order the Wyeast over the internet which takes 5 days to ship to me. I use a swamp cooler. Normally I wait until the airlock starts to bubble before I add frozen water bottles to the swamp cooler.  I bought the Creme Ale from NB which uses Wyeast 1056 (American Ale).  However, this was the first time I didn't order the Wyeast from NB; instead I purchased it from the LHBS because I figured the 5 day shipping from NB was harmful.  I also ordered a Dead Ringer IPA which uses the same yeast.  I made two yeast starters. The one for the Creme Ale had an OG of 1050 and the one for the IPA had an OG of 1040. The IPA definitely was a better yeast starter.  I aerated the creme ale wort (1040 OG) with an areation stone and pitched the entire 1050 yeast starter into it. This time I decided to stir up the yeast in the wort. This time I decided to put 6 frozen water bottles into the swamp cooler immediately instead of waiting until the airlock started bubbling. Using a temperature probe I kept the swamp cooler at 60*F by adding frozen water bottles. The lid was completely sealed.  After 24 hours the airlock was not bubbling, so I purchased another Wyeast 1056 from the LBHS and pitched it without a yeast starter at 48 hours. However when I opened the lid to the bucket I saw the following: (Is this fermentation activity or simply a result of me stirring the wort/yeast from 48 hours before?)   Around 2 hours later (50 total) the air lock started bubbling, so I figured that I was safe and that either the 1050 og of the yeast starter somehow destroyed the yeast (even though I successfully pitched 1060 og yeast starters before) or the Wyeast I bought was bunk. I then added 6 frozen water bottles to the swamp cooler to take it to 60*F.  When I woke up 10 hours later (60 hours total) the airlock stopped bubbling.  I only did three things differently this time:  1) The LBHS sold me bad yeast. 2) The frozen water bottles somehow stopped the fermentation. 3) Stirring the yeast into the wort somehow did something.  Questions:  What is the problem (if it is possible to diagnose over the internet), and what should I do now?  I am in the middle of brewing the IPA with a 1040 og yeast starter so I will report back. This time I will simply pitch the yeast starter and not stir it, and I won't add frozen water bottles until I see the airlock bubbling.


I am trying to create folder in the drive with the username:zedaan . I have try to chmod the drive still the same issue sudo chmod -Rf 777 /media/1666675566673521  Here are the drive lists:

I have messed up my sudoers file and I want to change the permission on it.   When I login in recovery mode, I cannot run the command chmod as it is read-only option.  I tried mount -o remount,rw / in recovery mode. Didn't work for me:  Err : Ext4-fs remount. Opts errors=remount-ro    How can I boot into recovery mode and with read-write option?


I bought a new battery for my camera assuming that it would be enough to be compatible, in Sony terms "NP-FW50". Though I think the generic is better than the original:   Generic: 7.4V, 1950mAh, 14.4Wh Original: 7.2V, 1020mAh, 7.3Wh   I believe higher mAh means it holds more power for longer.  So, is the generic better than the original? Or am I completely missing the point?

I need another LP-E5 type battery for my Canon 450D. Should I buy an original Canon battery or one of the many generic brands available? There are loads of cheapos on , for example.  I should add that the new battery will be added to my existing Canon battery in a battery grip.  Does anyone have any experience (good or bad) of using generic batteries?


I added some simple history command in order to get some info every time I am on a Ubuntu 18.04.2 LTS Dell local machine with bash 4.4.20(1)-release, shell /bin/bash. If I open a new shell: history | tail  but I noticed that when I open a new terminal it does show me anything, while if I: source ~/.bashrc  it works well. I guess it has something to do with history characteristics and new terminals but even googling and looking here I can not figure out what! Thanks in advance for any help! --- EDITED --- grep HIST ~/.bashrc ~/.profile ~/.bash_profile /home/enrico/.bashrc:HISTCONTROL=ignoreboth /home/enrico/.bashrc:# for setting history length see HISTSIZE and HISTFILESIZE in bash(1) /home/enrico/.bashrc:HISTSIZE=1000 /home/enrico/.bashrc:HISTFILESIZE=2000 /home/enrico/.bashrc:export HISTTIMEFORMAT="%Y-%m-%d %T " grep: /home/enrico/.bash_profile: No such file or directory

I consistently have more than one terminal open. Anywhere from two to ten, doing various bits and bobs. Now let's say I restart and open up another set of terminals. Some remember certain things, some forget.  I want a history that:   Remembers everything from every terminal Is instantly accessible from every terminal (eg if I ls in one, switch to another already-running terminal and then press up, ls shows up) Doesn't forget command if there are spaces at the front of the command.   Anything I can do to make bash work more like that?


Has anyone ever put together a version compatibility matrix for pgAdmin versions and PostgreSQL versions?

If you have different versions of PostgreSQL database servers you need a pgadmin III version with the respective pg_dump and pg_restore included.   I am running pgadmin III on a windows machine.   For example for PostgreSQL server 8.4.x you need pgadmin III with pg_dump 8.4.x, for PostgreSQL server 8.3.x you need pgadmin III with pg_dump 8.3.x and so on.  What I cannot figure out is how do you know which version of pgadmin III contains which version of pg_dump and pg_restore? I could not find the info on   I could just install some versions and try out, but maybe there is a better way.     pgadmin III V 1.8.4 comes with pg_dump 8.3.15


After experiencing a notable shocking type sensation after  coming into skin contact with my laptop and phone (both metal and plugged into their chargers), I decided to probe the chassis of both devices to discover a 50Hz 120V transient...   To investigate this further, I directly recorded the voltage from the grounds of the charger connectors to find the same transient. Swapping  between two different laptop and two different phone chargers, all permutations yield the a large AC signal from their grounds. That said, swapping between a 10W to a 5W usb charger did drop the difference to 60V between laptop and usb charger grounds.  I’ve even checked the sockets to ensure that its not a wiring problem, and sure enough the earth, live and neutral are all where they should be and connected properly. N.B. I’m in the UK, so 240V outlets.  This is quite baffling to me since not only are the voltages produced by the charging circuits direct current, but neither voltage exceeds 19.5V! Any explanations/diagrams to explain this would be fantastic!   Cheers!

I built the following circuit, a reference VIPer22A circuit.    It works fine but I have a little problem. It gives an electric shock on the secondary side. It's not a "line" shock (sticking your fingers into an outlet), but rather, a "tingly" shock if you touch the device while you're grounded.  It's the same thing that happens when you have an PC power supply not connected to mains earth.   The obvious solution would be, of course, to connect the secondary GND to Earth. The problem I have with this is that this is an audio amplifier, so I'd rather leave GND floating.  Is there a way to eliminate this shock? Capacitively connecting GND to EARTH? Or should I just connect my circuit's ground to Earth?


At the end of Guardians of the Galaxy we see Rocket take a twig of Groot and propagate it as a cutting.  Why stop at one? Why not grow an entire  forest of Groots?

While Groot is a formidable brawler, he is not impervious (he is made of wood, after all), and often finds himself reduced to nothing but kindling.  Thankfully, planting even a splinter of Groot's remains allows him to regenerate and regrow.   How long does it take for Groot to regrow to "full" size? Can multiple splinters of Groot be replanted? Would this result in multiple Groots?


I have used Latex several times for small papers and thesis' for University. So I know a bit about how to create formulars, tables and stuff. However, I still consider myself a newbie, who barely scratched the surface (for example, most of the problems I come across, in order to save time, I just google the answer and apply it without really understanding the reason behind an error).   A friend of mine suggested Luatex to me, since it lets you automate more things via the Lua scripting language and therefore according to him, with that you can really  decouple the semantics from the presentation (which isn't really possible for standard Latex).   I did a bit of google-ing around and I am a bit at a loss, as more and more questions are appearing. Here are some of them:   Is LuaTex still developed and supported What is Context? Is this still developed/supported. Is it recommended over Luatex, a complete different thing, or a competitor? There is a lot of knowledge for standard Latex our there (here). How is that for LuaTex and Context in case I have a problem.  How about other versions: XeTex, Koma-Tex,... How do you install those versions? Does it run along with your standard Latex version (In my case I use MikTex and work in TexnicCenter) What is recommended to use...let's say for a Master or PhD Thesis (a technical, math-heavy one) in 2019?   I know these are partly a bit oppinion-based questions, what I'm looking for in general is a Site, that summarizes these things and gives a good overview (and is up to date).

I’m interested in the differences and commonalities between the “new” (La)TeX processors:   , , and .   Personally, I’ve only used XeTeX so far and without having the time to try out all three systems, I’m having a surprisingly hard time setting them off from one each other.  As I understand it, these systems are actually very different in some regards. So I’m explicitly asking for strengths and weaknesses in every-day use (whatever that is), rather than very special scenarios.  (I’ve already asked a  on Super User some time ago.)


I'm trying to teach myself how to get the x and y co-ordinates clicked in a canvas to write games with. The code I've written has a subtle bug I can't figure out. When you click on the canvas, the ball moves roughly to where you clicked. But I want it centred on where I click. Instead that point is in the upper left corner of the new ball.  (I've edited the code to work correctly by using subtracting canvas.offsetLeft from the returned event.clientX and canvas.offsetTop from event.clientY, two properties I wasn't aware of until pointed to a similar post.)    var canvas, context, ball_pos;  var BALL_RADIUS = 15;  function start() {     'use strict';     canvas = document.getElementById('c');     context = canvas.getContext('2d');     ball_pos = [canvas.width / 2, canvas.height / 2]; }  function draw() {     'use strict';      // draw background     context.fillStyle = "rgb(248,248,248)"; // off white     context.fillRect(0, 0, canvas.width, canvas.height);      // draw ball     context.strokeStyle = 'black';     context.lineWidth = 1;     context.fillStyle = 'red';     context.beginPath();     context.arc(ball_pos[0], ball_pos[1], BALL_RADIUS, 0, Math.PI * 2, true);     context.closePath();     context.fill();     context.stroke(); }  function animate() {     'use strict';     window.requestAnimationFrame(animate);     draw(); }  function click(evt) {   ball_pos[0] = evt.clientX - canvas.offsetLeft;   ball_pos[1] = evt.clientY - canvas.offsetTop; }  // register event handlers window.onclick = click;  start(); animate(); <!DOCTYPE HTML> <html> <head>   <meta charset="utf-8"> </head> <body>   <canvas id="c" width="600" height="400"></canvas> </body> </html>

What's the simplest way to add a click event handler to a canvas element that will return the x and y coordinates of the click (relative to the canvas element)?  No legacy browser compatibility required, Safari, Opera and Firefox will do.


Searching many examples I didn't manage to solve my case. I have an array that should be sorted by author. My attempt did nothing. What is the right expression?   var array = [   ["ifke", {     "title": "secure",     "author": "admin"   }],   ["lottery", {     "title": "The lo",     "author": "anton"   }],   ["short-content", {     "title": "Short Content",     "author": "scott"    }],   ["ziddler", {     "title": "The Fiddler",     "author": "herman"    }] ];   array.sort((a, b) => a[1].author - b[1].author) console.log(array)

I have a list of objects I wish to sort based on a field attr of type string. I tried using -  list.sort(function (a, b) {     return a.attr - b.attr })   but found that - doesn't appear to work with strings in JavaScript. How can I sort a list of objects based on an attribute with type string?


Is there an online advanced/intermediate tutorial on Selenium Webdriver. Preferably using Java. I've searched a lot but could not find such a course/tutorial. Almost 99% are very basic, and I would like to do more advanced testing with Selenium Webdriver.   Thank you.

So I've been testing web based analytical software now for the past 4 years or so with mostly manual techniques. But for 2015, I've set myself the goal of getting setup and start writing automated tests and to introduce automated testing into my company.  I've done a little research and it seems that Selenium is quite big when it comes to writing automated tests, but most of the tutorials I've come across reference the Java language.  Some questions:   Is Java the primary language used for Selenium tests?  Do you recommend it over C# ?  Wat is the process of writing test scripts?  Are there Frameworks that I should use that can make the process even easier?


For every point $(a,b)\in \mathbb{R}^2$, such that $a + b = 1$, find the limit: $$\lim_{(x,y)\to(a,b)}\frac{y\sin\pi x}{x+y-1}$$ We have three cases, $a = 0 $ and $ b=1,$ $b=0$ and $ a=1$, and finally $a, b\not\in\{0,1\} $. I solved the first case, there was no limit, but I have no idea how to tackle the rest of them.

If $(a,b) \in \Bbb R^2$ and $a+b=1$, calculate the following limit or demonstrate that there is none: $$ \lim_{(x,y) \to  (a,b)}  \frac {y\sin(\pi x)}{x+y-1}$$  I'm doing that: $\lim_{(x,y) \to  (a,b)}  \frac {y\sin(\pi x)}{x+y-1}=\lim_{(x,y) \to  (0,0)}  \frac {(y+b)\sin(\pi (x+a))}{x+y}$ $$ f(x,y)=  \frac { (y+b) \sin(\pi (x+a))}{x+y}  \Rightarrow f(0,\frac {1}{n})=  \frac{(\frac{1}{n}+b) \sin \pi a}{ \frac{1}{n}}= \sin \pi a + n b \sin \pi a  $$ I can get that : If $ a  \in  \Bbb Z \lim _{n \to \infty} f(0,\frac {1}{n})=0  $ and if $a \notin \Bbb   Z $ function doesn't limit.   Why this funtion no limit ,when $ a \in \Bbb Z  $ ?  Help me, please.


I'm used to use this service because I like to use my wireless card as a hotspot, but since yesterday the service doesn't start anymore. The last time I tried to enable connection sharing, COM Surrogate stopped responding so I saw ICS service was stuck at "starting" and never starts. I already restarted my computer, checked service's dependencies, disabled firewall and nothing worked.   What's going on?

Since installing the Windows 10 Fall Creators Update, I have a svchost.exe process that is constantly using about 14 % of CPU time:    This svchost.exe instance is responsible for hosting three services:    The CPU time is consumed by a thread inside that process that  cannot attribute to any of these three services:    Given that these three services are considered critical system services, it's hard to do anything about them. These services cannot be stopped or disabled by services.msc, and terminating the process triggers a bugcheck (CRITICAL_PROCESS_DIED). Disabling the Windows Defender Firewall through the settings UI does not reduce CPU usage.  I'm out of ideas. What could be causing this? How can I debug this further? Is there a workaround to stop these services?    Update: After some debugging with , we've isolated this to the Windows Defender Firewall service. Process Monitor shows that it's constantly accessing the registry:    A CSV export of a Process Monitor capture, filtered to that process, is available .  I’m still looking for a way to stop that behavior.    Update 2: Analysis with the Windows Performance Analyzer shows that most CPU time is consumed by code from rpcrt4.dll: