I have a file name (including an extension, but not a full path name) in variable file, and I want to only get the last 10 characters of the base name from a parameter expansion.  Example: file contains the filename A_text_document_1234567890.txt.  Desired output: 1234567890.  I know that I can use ${file%.*} to remove the extension: echo ${file%.*} outputs A_text_document_1234567890.  If I do base=${file%.*}, then I can use ${base: -10} to get 1234567890.  Can I do this inside the parameter expansion all in one step without using a second variable?  I guess my real question is, how do I combine these two parameter expansions into one?

I have a file named 35554842200284685106000166550020003504201637715423.xml and I simply need to rename it to 42200284685106000166550020003504201637715423.xml (remove everything before the last 48 characters). This simple regular expression (.{48}$) can extract the last 48 characters, but I can't make it work using rename in Bash.  How can I use rename and this regular expression to rename it to only the last 48 characters?  Edit:  Output of rename --help  [root@ip-000-00-0-000 tmp]# rename --help  Usage:  rename [options] <expression> <replacement> <file>...  Rename files.  Options:  -v, --verbose    explain what is being done  -s, --symlink    act on the target of symlinks  -n, --no-act     do not make any changes   -h, --help     display this help and exit  -V, --version  output version information and exit  For more details see rename(1).   Thank you.


Recently I'm facing a problem on derangement. The problem I'm facing is asked in the link:   An answer is also given in that link. But I can't understand the answer.  Can anyone tell me the solving way with better explanation and great details.I again asked the question in the following.  A derangement of $n$ numbers is a permutation of those numbers in which none of the numbers appears in its original place.   For example, the numbers $\{1,2,3\}$ can be deranged into $\{2,3,1\}$ and $\{3,1,2\}$. We can modify this slightly for $n$ numbers that are not necessarily distinct by saying that no number in the derangement can be in the place that a number of the same value was in in the original ordering. So the numbers $\{1,1,2,2,3\}$ could be deranged into $\{2,2,1,3,1\}$, $\{2,2,3,1,1\}$, $\{2,3,1,1,2\}$, and $\{3,2,1,1,2\}$.  How can I find out the number of above derangement if a set like above is given?

Find the number of ways a string of numbers (that may contain similar items) can be deranged, so that a number is not placed in the same place as it or its similar numbers were placed. For example, $\{0,0,0,1,1,1\}$ can be arranged in only one way, and that is $\{1,1,1,0,0,0\}$. $\{0,0,0,1,1,1,1\}$ cannot be arranged in any way. $\{1,2,2,14\}$ can be arranged in $2$ ways, i.e $\{2,1,14,2\}$, $\{2,14,1,2\}$. $\{1,1,2,2,14\}$ can be arranged in $5$ ways, i.e $\{2,2,1,1,14\}$, $\{14,2,1,1,2\}$, $\{2,2,14,1,1\}$, $\{2,2,1,14,1\}$, $\{2,14,1,1,2\}$.  Please do try and respond. Thanks in advance.


Fellow people of the internet,  I got an issue with Xterm, as i try to use a zsh theme using unicode characters. However, Xterm refuses to print them, which is a bit annoying. My Xressources is a followed :  hereXTerm*reverseVideo: on xterm.vt100*FaceName:   hack XTerm*FaceSize:         15   My locale is set to "C", for all of it, i guess the issue comes from here, but i surprisingly don't find a way to set it to en_US.UTF-8, even if it is the only uncommented line in my locale.conf. We are talking basically any unicode character, for instance ❌, which is translated into # followed by 2 blanks.  . My command line basically looks like this :   While it is supposed to look like this :  If it can be of any help, i'm running the latest version of arch.  EDIT: Updating to UTF-8 doesn't solve the issue.  Is there any chance one of you have a solution ? Thanks

I use xterm (X-Win32 2012 Build 30 from StarNet Communications Corp) to login from a Windows 7 PC to a Red Enterprise Linux 6 (RHEL6).  My problem is that all multi-byte utf-8 characters comes out garbled in the xterm login shell. For example, here's how the string "Wilhelm Röntgen" is rendered in the two shell instances (the font used is a Unicode font and is the same font in both shell instances):   Login shell: Wilhelm RÃ¶ntgen  Second shell: Wilhelm Röntgen   If I've understood things correctly the software from rom StarNet Communications Corp implements (or emulates) a X terminal (a thin client that runs a X server).  I.e. both shell instances runs in a X terminal window on the PC, and communicates with RHEL6 using the X11 protocol.  Below is how both shells appear on my desktop, catenating a file with unicode multibye characters to the terminal.    Here is the command I've configured  X-Win32 to use to start the login shell:  xterm -u8 -ls   However, after I login, I can do xterm in the login shell, and that command that will fork a new xterm instance where locale setting works as expected (i.e. utf-8 characters are rendered correctly).  Here is the relevant settings as they appear in the login shell:  $ locale LANG=en_US.UTF-8 LC_CTYPE=en_US.UTF-8 LC_NUMERIC="en_US.UTF-8" LC_TIME="en_US.UTF-8" LC_COLLATE=C LC_MONETARY="en_US.UTF-8" LC_MESSAGES="en_US.UTF-8" LC_PAPER="en_US.UTF-8" LC_NAME="en_US.UTF-8" LC_ADDRESS="en_US.UTF-8" LC_TELEPHONE="en_US.UTF-8" LC_MEASUREMENT="en_US.UTF-8" LC_IDENTIFICATION="en_US.UTF-8" LC_ALL=  $ printenv XTERM_LOCALE en_US.UTF-8   I also have the following two lines in .Xresources:  xterm*locale: true xterm*utf8: 1   It looks like the login shell xterm doesn't recognise the locale I've set, but I don't understand why not.  My xterm is clearly capable of this, since all non-login shells do this by default.


I know that there are a few posts about this and I have been reading them for a while now but still, I can't resolve my issue.  I’m running ISPconfig with postfix and I can’t figure out why my outgoing emails are marked as spam in gmail and outlook.com.   Reverse DNS is fine I set up SPF DKIM and DMARC (when I look in headers for a gmail email it says pass, same for outlook) I’m not blacklisted Mxtoolbox check is ok (it returns only too warning related to SOA expire value and Name server on same network) HELO is returning the proper name I tried different content in the email / plain text etc … I changed headers to display the right hostname instead of localhost I tried to use a different IP  I’m not using the server to send bulk emails.   Here is the result when I send a mail to check-auth@verifier.port25.com.  ========================================================== Summary of Results ========================================================== SPF check:          pass DomainKeys check:   neutral DKIM check:         pass Sender-ID check:    pass SpamAssassin check: ham   Here is the content of an email to gmail :  Delivered-To: xxxxx@gmail.com Received: by 10.37.115.87 with SMTP id o84csp2701146ybc;         Wed, 14 Oct 2015 02:24:12 -0700 (PDT) X-Received: by 10.180.23.231 with SMTP id p7mr27203112wif.30.1444814652908;         Wed, 14 Oct 2015 02:24:12 -0700 (PDT) Return-Path: <xxxxx@xxx.fr> Received: from xxx.xxx.fr (xxx.xxx.fr. [xxx.xxx.xxx.xxx])         by mx.google.com with ESMTPS id ao6si9344594wjc.158.2015.10.14.02.24.12         for <xxxxx@gmail.com>         (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128);         Wed, 14 Oct 2015 02:24:12 -0700 (PDT) Received-SPF: pass (google.com: domain of xxxxx@xxx.fr designates xxx.xxx.xxx.xxx as permitted sender) client-ip=xxx.xxx.xxx.xxx; Authentication-Results: mx.google.com;        spf=pass (google.com: domain of xxxxx@xxx.fr designates xxx.xxx.xxx.xxx as permitted sender) smtp.mailfrom=xxxxx@xxx.fr;        dkim=pass header.i=@xxx.fr;        dmarc=pass (p=QUARANTINE dis=NONE) header.from=xxx.fr Received: from mail.xxx.fr (mail.xxx.fr [127.0.0.1])     by mail.xxx.fr (Postfix) with ESMTP id 761538392E     for <xxxxx@gmail.com>; Wed, 14 Oct 2015 11:24:12 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=xxx.fr; h=     user-agent:message-id:from:from:date:date     :content-transfer-encoding:content-type:content-type     :mime-version:subject:subject; s=default; t=1444814652; x=     1446629053; bh=ZRVRT3UM6A3vr5Bjs0V90xDPq6+kbcb9HUlVjWHZ8Vc=; b=Y     pcDBU5OXZZsskSavKUNkbU8+TApXPx98+fJCXc4/5UkEXuLa7fNT/8HWidm0m8y2     chyd8e03x3u7keKwLXdKQz4SOoo1baIdB55DwY0tNebusGegoxnARAoVk1RoqO1E     e4FlvW5FkG4CNlPrFDEa0FKvURIDy+5g/dpS89k6UY= X-Virus-Scanned: Debian amavisd-new at mail.xxx.fr Received: by mail.xxx.fr (Postfix, from userid 33)     id 525068392A; Wed, 14 Oct 2015 11:24:12 +0200 (CEST) To: <xxxxx@gmail.com> Subject: Envoi depuis webmail X-PHP-Originating-Script: 0:main.inc MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8;  format=flowed Content-Transfer-Encoding: 7bit Date: Wed, 14 Oct 2015 11:24:12 +0200 From: Damien Lxxxxxxx <xxxxx@xxx.fr> Message-ID: <89350fb9a97732f74b1cbb8f7a1988ad@xxx.fr> X-Sender: xxxxx@xxx.fr User-Agent: Roundcube Webmail/0.7.2  Bonjour,  Merci de me recontacter.   Do you have any idea what’s wrong with my setup?  Thank you.

This is a  about how to handle email sent from your server being misclassified as spam.  For additional information you may find these similar questions helpful:                    Sometimes I want to send newsletters to my customers. The problem is, that some of the emails get caught as spam messages. Mostly by Outlook at the client (even in my own Outlook 2007).  Now I want to know what should be done to create "good" emails. I know about reverse lookup etc., but (for example), what about a unsubscribe link with an unique ID?  Does that increase a spam rating?


In windows, I used to connect my phones (Samsung Galaxy S3 I9300 & Samsung Galaxy Note3 N9005) to my PC after installing the USB driver, and  enable USB Debuggng in the phone and debug my applications using the Android Studio. I installed the Android Studio on Ubuntu but I don't know how to install the driver or how to connect my phone in debugging mode. when I connect the phone I can read the phone as a storage.

My computer is a Sys76 Lemur running Maverick, and my phone is a Nexus S running stock Gingerbread. I want to set up to use ADB (android debug bridge). I installed the Android SDK per instructions on the SDK website, but ADB doesn't work. Can someone help me with directions that are specific to Ubuntu?


I was asked to calculate a confidence score for a single proportion representing a conversion rate. I saw a lot of documents that calculate confidence intervals for proportions based on the binomial distribution; however I did not see any material for a single conversion (or proportion). If $X \sim Bin(n,p)$, with large sample size normal approx to binomial is valid, then  $$ \hat{p} \leadsto \mathcal{N}\bigg( p, \sqrt{\frac{p(1-p)}{n}} \bigg) $$  Using this approximation, I saw statistical significance involving a second ratio (through $z$-scores) can be calculated, etc. However, can any error metric be calculated for a single proportion? Ideally this metric would be a number between 0% and 100%.

I have a random sample of Bernoulli random variables $X_1 ... X_N$, where $X_i$ are i.i.d. r.v. and $P(X_i = 1) = p$, and $p$ is an unknown parameter.  Obviously, one can find an estimate for $p$: $\hat{p}:=(X_1+\dots+X_N)/N$.  My question is how can I build a confidence interval for $p$?


Please, I want to change the symlink to the new path My symlink's in this form  lrwxrwxrwx. 1 s01 s01 56 Mar 22 13:17 zmjppcxlpq2m.png -> /home/s01/public_html/cgi-bin/uploads/00029/zmjppcxlpq2m lrwxrwxrwx. 1 s01 s01 56 Mar 23 17:03 znviy3civtq3.jpg -> /home/s01/public_html/cgi-bin/uploads/00029/znviy3civtq3 lrwxrwxrwx. 1 s01 s01 56 Mar 24 20:07 zoi46hh4pu32.jpg -> /home/s01/public_html/cgi-bin/uploads/00029/zoi46hh4pu32 lrwxrwxrwx. 1 s01 s01 56 Mar 23 18:22 zqt0h1gy9e4c.png -> /home/s01/public_html/cgi-bin/uploads/00029/zqt0h1gy9e4c   I transferred all files to a new portion from /home to /home2    So I want to change all symlinks to the new path. Ex:  Old:  zmjppcxlpq2m.png -> /home/s01/public_html/cgi-bin/uploads/00029/zmjppcxlpq2m   I want to have  zmjppcxlpq2m.png -> /home2/s01/public_html/cgi-bin/uploads/00029/zmjppcxlpq2m   for all files. what can I do?

I have a directory tree which has a bunch of symbolic links to files under /home... however, I have moved /home to /mnt/home and need a way to "relink" all of the symlinks. Does such functionality exist or do I need to write a script to do so?   As an example, I have something like the following:  [root@trees ~]# ls -l /mnt/home/someone/something total 4264 lrwxrwxrwx 1 jnet www-data      55 2011-08-07 13:50 a -> /home/someone/someotherthing/a lrwxrwxrwx 1 jnet www-data      55 2011-08-07 13:50 b -> /home/someone/someotherthing/b lrwxrwxrwx 1 jnet www-data      55 2011-08-07 13:50 c -> /home/someone/someotherthing/c lrwxrwxrwx 1 jnet www-data      55 2011-08-07 13:50 d -> /home/someone/someotherthing/d lrwxrwxrwx 1 jnet www-data      55 2011-08-07 13:50 e -> /home/someone/someotherthing/e  /mnt/home/someone/something/subdir: total 4264 lrwxrwxrwx 1 jnet www-data      55 2011-08-07 13:50 a -> /home/someone/someotherthing/subdir/a lrwxrwxrwx 1 jnet www-data      55 2011-08-07 13:50 b -> /home/someone/someotherthing/subdir/b lrwxrwxrwx 1 jnet www-data      55 2011-08-07 13:50 c -> /home/someone/someotherthing/subdir/c lrwxrwxrwx 1 jnet www-data      55 2011-08-07 13:50 d -> /home/someone/someotherthing/subdir/d lrwxrwxrwx 1 jnet www-data      55 2011-08-07 13:50 e -> /home/someone/someotherthing/subdir/e   I want a command which will find all the symlinks and relink to the same places but underneath /mnt/home instead of /home  Does such a command exist?


Can you help me prove that the $\sum \limits _{p \text{ prime}} \dfrac 1 p$ is divergent?

Does the series $\sum_{n=1 }^{\infty}1/p_{j} $ of  reciprocal primes converge?  Experimentally, it seems convergent.


The infinite power tower or infinite tetration ${\displaystyle z^{z^{z^{\cdot ^{\cdot ^{\cdot }}}}}\!}$ is generally expressed in terms of the Lambert W function in the following form:  ${\displaystyle {\frac {W(-\ln(z))}{-\ln(z)}}}$  Considering the integral  $\displaystyle \int -\frac{W(-\ln (z))}{\ln (z)} \, dz,$  Does this integral have a closed form solution?  Is there a series expansion for this integral?

What is $\int{x^{x^{x^{x^{\dots }}}}dx}$? I managed to get it down to a complicated series after using $u$-substitution, but I want to see other methods of approach, or if my answer was right.   First I let $$u=x^{x^{x^{x^{\dots }}}}$$, and $du$ would be, in terms of $u$, $$du=  \frac{u}{\frac{1-ln(u)}{u}e^{ln(u)/u}}$$ This makes the integral of $$\int{x^{x^{x^{x^{\dots }}}}dx}=\int \frac{1 - ln(u)}{u}{e^{ln(u)/u} }du$$ Now making $w = ln(u), dw$ becomes $1/u$ and the integral becomes $$\int e^{w/e^{w}}(1-w)dw$$ From there, I distributed and made $2$ integrals of series, using the Taylor polynomial for $e^x$. From there, I integrated and back substituted. I was only trying to find the indefinite integral.   I'm still a junior in high school, so let me know if the answer is beyond my scope of understanding.


I have SQL Server 2016. One of the table is having 9.24 million records. One of the stats (no filter on stats) on it is getting auto updated by SQL Server with sampling rate of 1 % (120023 rows). As per the formula mentioned in below URL, sampling % should be around 5 % but that is not the case. I want to know why? Am I missing something? Or there is no standard formula for it?  Also just wanted to verify the threshold (modification counter) for updating the stats in SQL Server 2016 is (mentioned below) or something else will cause the delay / premature update of stats (I know REBUILDING INDEXES will update stats indeed)? Threshold = √((1000)*Current table cardinality)

From :     When none of the sample options (SAMPLE, FULLSCAN, RESAMPLE) are   specified, the query optimiser samples the data and computes the   sample size by default.   How to identify default sample size of statistics?   I went through MSDN but didn't find any formula or method to identify the default sample size. Everywhere there are only formulas present to trigger the auto statistics update. Any pointers will be helpful.


If I have a list with 600,000 elements  The list I have is quite complicated, and has nothing to do with sequence or order, but let's use this one with 600,000 elements as an example:  main_list = list(range(0,1200000,2)   and if I want to to create a list that slices the main_list into a new list likes this:  sub_list =  [main_list[0:100], main_list[100:200], main_list[200:300], main_list[300:400], ...]   How can I do it?

I have a list of arbitrary length, and I need to split it up into equal size chunks and operate on it. There are some obvious ways to do this, like keeping a counter and two lists, and when the second list fills up, add it to the first list and empty the second list for the next round of data, but this is potentially extremely expensive.  I was wondering if anyone had a good solution to this for lists of any length, e.g. using generators.  I was looking for something useful in itertools but I couldn't find anything obviously useful. Might've missed it, though.  Related question:


I am reviewing something when I accidentally press the site logo, which brings me to the front page of the site. Then I click the review button to the left of my info (avatar/rep/badge) and find that the number of the "number of review list items" is decreased by one, and the post I was reviewing no longer shows up in the rest of the queue. I think it has been automatically skipped when the review page was interrupted.  To reproduce:  Go to a site where you have access to a review, preferably FP. Note the number and click the title First Posts to obtain the first review item. Now don't do anything and click the site logo (or simply close the page). Re-navigate to the review page (//something.stackexchange.com/review) and you'll find the number decreased by one. If possible, you can finish the queue amd you won't find the "skipped" rev item.

I've been avidly checking the review page on StackOverflow, and I am a little curious as to how posts are allocated to reviewers.  Obviously, being a relatively new member, I only have access to new post and late answer reviews.  The queue is usually empty for me, but then I will notice some new questions from apparently first time posters on the new questions page. Also, while sometimes 2 questions are in the queue, it often says I am finished after completing one review.  Could anyone elaborate on how the system distributes reviews?


Every mobile radiates its signal to its nearest tower during phone call.Then is it possible for two mobiles to communicate with out using any tower with in range of 100 meters or more .If it is possible then we call a person who is beside me for free of cost . Thanks in Advance.

Can Cell Phones be (legally) used Adhoc, (ie, Point-to-Point) Communication?  For example, let's say I'm in a remote area of the woods, or a valley.  Can I configure cell phones to be used as true walkie-talkies even though neither one of them use has a cell phone tower?  (Besides, it might be handy to use this on, oh, say, a drone, for photography purposes.  I intend to comply with all regulations regarding use of my drone.)  This goes for those modules too, I can hook them up to a , for example.    In the latter case I could just buy a nice antenna, I guess....   What kind of range would either of these things have if they are feasible?  I wanted to get my ham radio license, but I have my second year of engineering school to finish up.  Also: Might you suggest any alternatives (I hope this doesn't make my askance too open- but, it may be worth noting , or moreover, it's very upvotable answer! Alas, I doubt they have too much bandwidth...)


So, I'm a total Java newb and I wanted to make an animation program but I wanted to do it my own way so I understand how it works, I know there may be other questions like this but I wanted to know the answer using the code I made, so here is my code, the problem is when I run this the box doesn't show up on the window and looking at my prints it stops right before i set the color. Can anyone help?  import java.awt.Color; import java.awt.Component; import java.awt.Graphics;  import javax.swing.JFrame; final public class main extends JFrame{     private int x = 20;     private int y = 20;      private boolean right = true;     private boolean left = false;     private boolean down = true;     private boolean up = false;      public static void main(String[] args){         JFrame JFrame = new JFrame("On My Own (kinda)");         JFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);           JFrame.setVisible(true);         JFrame.setLocation(375, 55);         JFrame.setSize(300, 300);         new main().Animate();     }      public void draw(){         System.out.println("2");         Graphics g = getGraphics();         System.out.println("3");         g.setColor(Color.BLACK);         System.out.println("4");         g.fillRect(x, y, 6, 6);         System.out.println("5");     }      public void Animate(){         System.out.println("1");         while(true){             //Game loop             if(x >= 283){                 right = false;                 left = true;             }             if(x <= 7){                 right = true;                 left = false;             }             if(y >= 259){                 up = true;                 down = false;             }             if(y <= 7){                 up = false;                 down = true;             }             if(up){                 y--;             }             if(down){                 y++;             }             if(left){                 x--;             }             if(right){                 x++;             }             try{                 Thread.sleep(10);             } catch (Exception exc){System.out.println("OOOPS");}             draw();         }     }  }   And this is what I get  1 Exception in thread "main" java.lang.NullPointerException     at main.draw(main.java:30)     at main.Animate(main.java:71)     at main.main(main.java:23) 2 3

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


I am making this Christmas Tree but the problem is that I can't render the whole scene in one go because of too many particles. So I have rendered my tree and now I want to render only tinsels wrapped around the tree but I want it as png with alpha so that I can add them together as layers. So how can I do this? Thanks.  Tree   Tinsel

Is there a material or render setting which makes the whole rendered image transparent at the spot of an object? I.e. not to create only a transparent object where the background is visible, but a transparent „hole“ with Alpha=0? I know that this can be achieved post-rendering by the Compositor and e.g. Cryptomatte, but I would like to define the transparent areas before rendering. Greetings from Germany, Tschöbbel


So I have quite a simple question, but basically I have a picture of a model and want to save it as transparent. So I went up to the Render Layers panel, Layers, and deselected "sky" and rendered it out. It showed that checkered grey background with the object still there, so things were going good! I saved it, but for some reason there is a black background and it isn't a transparent image. Any help? Thanks!

I would like to render an animation as a series of .png images with transparent backgrounds for use in a video. Is this possible?


Although it is very appropriate for the appraisal that I am writing, it has become overused in our workplace.  Any suggestions for alternate wording is appreciated.

I'm looking for an idiom or saying that I could use when people are focusing too much on small details and not seeing the big picture.  A couple that come to mind are "being penny-wise and pound foolish" and "rearranging deck chairs on the Titanic". However, the former doesn't fit what I'm thinking of because the present activity might not be wise. The latter implies too much about impending doom.  For example, let's say some company is spending all their time refining a small detail in their product, while ignoring a major opportunity shift in the industry. What phrase could I use there?


I have seen a few people discussing this, and I was wondering if anyone thought it was possible that in the Star Trek: The Next Generation episode, Chain of Command, the Cardassian interrogator Gul Madred had actually brought in a fifth light and that is why Picard said he saw five at the end of the episode? When Madred asks Picard for the last time, we can't see how many lights there actually are. I know the whole thing is supposed to be a reference to "1984" but TNG was clearly doing its own thing.

In Chain of Command, Part II Picard is tortured by Madred, a Cardasian who tries to force Picard to tell him there are 5 lights, when in fact the real number is four. He could have used any other method to break Picard’s will, but why four lights?  Is this a military training tactic, to instill obedience into troops? Or is it something else?


For some reason, certain Doubles in my Swift app are giving me trouble when converting to NSNumber, while some are not. My app needs to convert doubles with 2 decimal places (prices) to NSNumbers so they can be stored and retrieved using Core Data. For example, a few particular prices such as 79.99 would evaluate to 99.98999999999999 unless specifically formatted using NSNumber's doubleValue method.   Here selectedWarranty.price = 79.99 as shown in debugger  // item.price: NSNumber?        // selectedWarranty.price: Double?    item.price = NSNumber(double: selectedWarranty.price!)   I programmed some print statements to show how the conversion works out  Original double: 79.99 Converted to NSNumber: 79.98999999999999 .doubleValue Representation: 79.99   Can somebody explain if there is a reason why the initializer cannot surely keep 2 decimal places for every number? I would really like to store the prices in Core Data like they should be. Formatting every time it is displayed doesn't sound very convenient.    UPDATE: Converted Core Data object to type NSDecimalNumber through data model, 79.99 and 99.99 no longer a problem, but now more manageable issue with different numbers...  Original double: 39.99 Converted to NSDecimalNumber: 39.99000000000001024

Consider the following code:   0.1 + 0.2 == 0.3  ->  false   0.1 + 0.2         ->  0.30000000000000004   Why do these inaccuracies happen?


I know that qustiosn was was asked before. I have tried to find an OSM key on the web, but without success. I know that I need to enter the API key by going in this order: web- OpenLayers Plugin-OSM/Thunderforest-Set API KEY  How and where can I find the API Key that need to be paste in this window?  I opened an account at , paste the API key, but it did not solve the problem

Could someone let me know how I add a API key to QGIS 2.14.10. The diagonal API key required is still on my map layer. Bit of a novice on QGIS.


Is there any site in the network where career development questions about the programming profession can be asked ? I thought Programmer's was the site for it, but that doesn't appear to be the case.

The  specifically says not to ask  for career advice but people do it anyway.  Should I consider the Help Center outdated or only loosely enforced?    And what about a career advice site on the network?  There are 70+ sites, and most of them are for relatively narrow interests (which is not a criticism, I enjoy looking through the many sections).  A career section seems like it would be very popular.  Also, a careers section would help keep career questions off the other sites.


The locked post FAQ says locked posts cannot be edited, yet  can be edited (at least, the lock message says so, and I can open the edit dialogue).

A post can be locked.   What does it mean to lock a post? Who can lock a post? When should a post be locked?


With the below code:  struct S { unsigned char b1 : 3; int i; };   I can deduce that char b1 is of 1 byte and using 3 bits of that and int is 4 bytes but when I try to print out the size of S, I get it 8 bytes instead of 5 bytes(1 for char+4 for int) as I expected and this is something I am not understanding by obvious. Can something explain why size of S is 8 bytes?

Why does the sizeof operator return a size larger for a structure than the total sizes of the structure's members?


I'm new to P-Values and Hypothesis testing and I noticed that p-values are explained differently everywhere I go. In my lecture notes it has a method for hypothesis testing and the last part says that "if the p-value is not small enough to rule out chance, we fail to reject null hypothesis". A p-value is stated as:  the probability of observing a value of the test statistic at least as contradictory to the null hypothesis as the one computed from the sample data"  Now, what doesn't make sense to me is that if p-value tells me the probability of observing a value of a test statistic at least as contradictory to the null hypothesis, then surely a low p-value(less than significance) would mean that it isn't very contradictory and thus we fail to reject but in fact they do it the other way around. I.e if p-value is less than significance, they actually reject null hypothesis?  Some sites say that the p-value is the strength of the evidence from the test statistic. Any clarificaiton?

I know that there are lots of materials explaining p-value. However the concept is not easy to grasp firmly without further clarification.  Here is the definition of p-value from Wikipedia:     The p-value is the probability of obtaining a test statistic at least   as extreme as the one that was actually observed, assuming that the   null hypothesis is true. ()   My first question pertains to the expression "at least as extreme as the one that was actually observed." My understanding of the logic underlying the use of p-value is the following: If the p-value is small, it's unlikely that the observation occurred assuming the null hypothesis and we may need an alternative hypothesis to explain the observation. If the p-value is not so small, it is likely that the observation occurred only assuming the null hypothesis and the alternative hypothesis is not necessary to explain the observation. So if someone wants to insist on a hypothesis he/she has to show that the p-value of the null hypothesis is very small. With this view in mind, my understanding of the ambiguous expression is that p-value is $\min[P(X<x),P(x<X)]$, if the PDF of the statistic is unimodal, where $X$ is the test statistic and $x$ is its value obtained from the observation. Is this right? If it is right, is it still applicable to use the bimodal PDF of the statistic? If two peaks of the PDF are separated well and the observed value is somewhere in the low probability density region between the two peaks, which interval does the p-value give the probability of?  The second question is about another definition of p-value from Wolfram MathWorld:     The probability that a variate would assume a value greater than or   equal to the observed value strictly by chance.   ()   I understood that the phrase "strictly by chance" should be interpreted as "assuming a null hypothesis". Is that right?  The third question regards the use of "null hypothesis". Let's assume that someone wants to insist that a coin is fair. He expresses the hypothesis as that relative frequency of heads is 0.5. Then the null hypothesis is "relative frequency of heads is not 0.5." In this case, whereas calculating the p-value of the null hypothesis is difficult, the calculation is easy for the alternative hypothesis. Of course the problem can be resolved by interchanging the role of the two hypotheses. My question is that rejection or acceptance based directly on the p-value of the original alternative hypothesis (without introducing the null hypothesis) is whether it is OK or not. If it is not OK, what is usual workaround for such difficulties when calculating the p-value of a null hypothesis?     I posted a new  that is more clarified based on the discussion in this thread.


I saw a question which asked the remainder of $18!$ when it is divided by $437.$ I tried to solve it using the Wilson's Theorem. Since $437=19\times23$ which both are prime, I can rewrite it to be $$18!\equiv-1\pmod{19}\text{,}\quad22!\equiv-1\pmod{23}.$$ Then, since $22!=22\cdot21\cdot20\cdot19\cdot18!,$ and $22!\equiv-1\pmod{23},$ $21!\equiv-2\pmod{23},$ $20\equiv-3\pmod{23},$ $19\equiv-4\pmod{23},$ I can rewrite it into $$(-1)\cdot(-2)\cdot(-3)\cdot(-4)\cdot18!\equiv-1\pmod{23}\iff24\cdot18!\equiv-1\pmod{23}.$$ Since $24\equiv1\pmod{23},$ then $18!\equiv-1\pmod{23}$. Now, I'm stuck here. I got that $18!\equiv-1\pmod{19}$ and $18!\equiv-1\pmod{23}$. Are there any relations between those two? Any helps would be very appreciated.

Prove $x \equiv a \pmod{p}$ and $x \equiv a \pmod{q}$ then $x \equiv a\pmod{pq}$ for $p\neq q$ distinct primes.  Where can I start with this proof? It looks similar to the Chinese Remainder Theorem, but that deals with two different a values.


I am doing some decimal multiplication that requires very high accuracy. For some strange reason, my code is a little inaccurate. Why is this happening? Code: #include <iostream> #include <iomanip> using namespace std;  int main() {     long double x=100, y=0.8;     cout<<setprecision(100)<<x*y; }   Output: 80.00000000000000444089209850062616169452667236328125  As you can see the first few digits are correct but the last few digits are wrong. This code is really simple and I think it has no errors. Can anybody tell me what is wrong?


I am trying to make a stack of linked lists and I am running into a error   Here is my deconstructor:  template <typename T> mystack<T>::~mystack() {     node_type* temp;     while (pTop != nullptr) {         temp = pTop;         pTop = pTop->getNext();         delete temp;     } }   The error is being thrown when I call this function   double process_line(std::istream& input) {   DS::mystack<double> stack;             //std::cout << stack.size();      if (isdigit((input.get()))) {         //stack.push(input.get);     }     else {      }      return 0; }   When I don't create a new stack I don't get the error but when I do I get this error code  Severity    Code    Description Project File    Line    Suppression State  Error   LNK2019 unresolved external symbol "public: virtual __thiscall DS::mystack<double>::~mystack<double>(void)" (??1?$mystack@N@DS@@UAE@XZ) referenced in function "public: virtual void * __thiscall DS::mystack<double>::`scalar deleting destructor'(unsigned int)" (??_G?$mystack@N@DS@@UAEPAXI@Z)  lob06   C:\Users\name\source\repos\lob06\processline.obj    1      Any help would be appreciated.

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.)


Somehow, something is eating up around 80GB of HDD space and I cannot figure out what. This is starting to become a major problem for me as I only have 100GB to play with and if I find something to delete, something else will just fill that space, until I can barely use the computer.  I have tried running ncdu -x -q to clear up as much as possible and it says that I am down to about 22G usage. I get the same with du, but I guess ncdu uses du  du -x -d1 -h / 4,0K    /srv 28K     /media 4,0K    /mnt 4,0K    /lib64 16K     /lost+found 3,3G    /home 588M    /opt 360M    /lib 23M     /build 9,7M    /bin 48M     /boot 27M     /etc 1,4G    /root 4,0K    /cdrom 6,9G    /usr 16M     /sbin 9,0G    /var 22G     /   And if I run df:   df Filesystem      1K-blocks       Used Available Use% Mounted on udev              2748080          4   2748076   1% /dev tmpfs              559400       1568    557832   1% /run /dev/sdc2       109481872  104180864         0 100% / none                    4          0         4   0% /sys/fs/cgroup none                 5120          0      5120   0% /run/lock none              2796996        688   2796308   1% /run/shm none               102400          8    102392   1% /run/user overflow             1024        236       788  24% /tmp /dev/sdd2      1953382140 1874376664  79005476  96% /media/munhunger/Shaman /dev/sda1      1953382140 1926088316  27293824  99% /media/munhunger/Holy /dev/sdb1      2930264060 2930264060         0 100% /media/munhunger/Glory  df -aTh Filesystem     Type             Size  Used Avail Use% Mounted on sysfs          sysfs               0     0     0    - /sys proc           proc                0     0     0    - /proc udev           devtmpfs         2,7G  4,0K  2,7G   1% /dev devpts         devpts              0     0     0    - /dev/pts tmpfs          tmpfs            547M  1,6M  545M   1% /run /dev/sdc2      ext4             105G  103G     0 100% / none           tmpfs            4,0K     0  4,0K   0% /sys/fs/cgroup none           fusectl             0     0     0    - /sys/fs/fuse/connections none           debugfs             0     0     0    - /sys/kernel/debug none           securityfs          0     0     0    - /sys/kernel/security none           tmpfs            5,0M     0  5,0M   0% /run/lock none           tmpfs            2,7G  688K  2,7G   1% /run/shm none           tmpfs            100M  8,0K  100M   1% /run/user none           pstore              0     0     0    - /sys/fs/pstore overflow       tmpfs            1,0M  236K  788K  24% /tmp binfmt_misc    binfmt_misc         0     0     0    - /proc/sys/fs/binfmt_misc systemd        cgroup              0     0     0    - /sys/fs/cgroup/systemd gvfsd-fuse     fuse.gvfsd-fuse  0,0K  0,0K  0,0K    - /run/user/1000/gvfs /dev/sdd2      fuseblk          1,9T  1,8T   76G  96% /media/munhunger/Shaman /dev/sda1      fuseblk          1,9T  1,8T   27G  99% /media/munhunger/Holy /dev/sdb1      fuseblk          2,8T  2,8T     0 100% /media/munhunger/Glory   Running du with sh flag(and x because I do not want to scan mounted disks)  du -xsh / 22G     /   What could be causing this, and what can I do to mitigate the problem? Running on a linux mint 17 from uname -a: 3.16.0-38-generic #52~14.04.1-Ubuntu  From running lsof | grep -Fw deleted:  lsof | grep -Fw deleted lsof: WARNING: can't stat() fuse.gvfsd-fuse file system /run/user/1000/gvfs       Output information may be incomplete.

I have an AWS linux instance with a root drive of 32GB. I have an EBS mount of 20GB  On my root I ran out of space, so I cleared out some files. However my root drive is still full. I can't find out why because when I look at sizes of the directories using du and ncdu they show the drive should have a lot of space.    df   I get the following results   Filesystem     1K-blocks     Used Available Use% Mounted on /dev/xvda1      32894812 31946092    848472  98% / devtmpfs         2017224       60   2017164   1% /dev tmpfs            2025364        0   2025364   0% /dev/shm /dev/xvdh       20511356  4459276  15003504  23% /mnt/ebs   My /dev/xvda1 is still full  After some research I installed a great tool ncdu to display disk space and the results are:  ncdu 1.10 ~ Use the arrow keys to navigate, press ? for help                                                                                --- / -------------------------------------                 4.2GiB [##########] /mnt                                1.5GiB [###       ] /var      1.2GiB [##        ] /usr    684.9MiB [#         ] /opt    464.3MiB [#         ] /home    141.7MiB [          ] /lib     53.5MiB [          ] /boot     21.2MiB [          ] /lib64     10.8MiB [          ] /sbin      8.1MiB [          ] /bin      7.1MiB [          ] /etc      2.7MiB [          ] /tmp     60.0KiB [          ] /dev     48.0KiB [          ] /root  e  16.0KiB [          ] /lost+found  e   4.0KiB [          ] /srv  e   4.0KiB [          ] /selinux  e   4.0KiB [          ] /media  e   4.0KiB [          ] /local  .   0.0  B [          ] /proc      0.0  B [          ] /sys      0.0  B [          ]  .autofsck   If I du -h my total is  8.3G    /  So why would my disk be 95% full when it clearly has a lot of space. Am I missing something to do with the mounts and is there any other tool I can run to find out why it is 95% full?


I am getting the following error msg when entering sudo apt-get update in terminal:  W: Duplicate sources.list entry cdrom://Ubuntu 13.10 _Saucy Salamander_ - Release i386 (20131016.1)/ saucy/main i386 Packages (/var/lib/apt/lists/Ubuntu%2013.10%20%5fSaucy%20Salamander%5f%20-%20Release%20i386%20(20131016.1)_dists_saucy_main_binary-i386_Packages)  W: Duplicate sources.list entry cdrom://Ubuntu 13.10 _Saucy Salamander_ - Release i386 (20131016.1)/ saucy/restricted i386 Packages (/var/lib/apt/lists/Ubuntu%2013.10%20%5fSaucy%20Salamander%5f%20-%20Release%20i386%20(20131016.1)_dists_saucy_restricted_binary-i386_Packages) W: You may want to run apt-get update to correct these problems   I'm running Ubuntu from a flash-drive. I've run apt get update several times, to no avail. How do I correct these?

I keep getting this warning whenever I try to run sudo apt-get update.  W: Duplicate sources.list entry http://archive.ubuntu.com/ubuntu/ precise-updates/main i386 Packages (/var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_precise-updates_main_binary-i386_Packages) W: You may want to run apt-get update to correct these problems   Below is the output from /etc/apt/sources.list file:  deb http://archive.ubuntu.com/ubuntu precise main restricted deb-src http://archive.ubuntu.com/ubuntu precise main restricted  deb http://archive.ubuntu.com/ubuntu precise-updates main restricted deb-src http://archive.ubuntu.com/ubuntu precise-updates main restricted  deb http://archive.ubuntu.com/ubuntu precise universe deb-src http://archive.ubuntu.com/ubuntu precise universe deb http://archive.ubuntu.com/ubuntu precise-updates universe deb-src http://archive.ubuntu.com/ubuntu precise-updates universe  deb http://archive.ubuntu.com/ubuntu precise multiverse deb-src http://archive.ubuntu.com/ubuntu precise multiverse deb http://archive.ubuntu.com/ubuntu precise-updates multiverse deb-src http://archive.ubuntu.com/ubuntu precise-updates multiverse  deb http://archive.ubuntu.com/ubuntu precise-security main restricted deb-src http://archive.ubuntu.com/ubuntu precise-security main restricted deb http://archive.ubuntu.com/ubuntu precise-security universe deb-src http://archive.ubuntu.com/ubuntu precise-security universe deb http://archive.ubuntu.com/ubuntu precise-security multiverse deb-src http://archive.ubuntu.com/ubuntu precise-security multiverse   How do I fix it?


Is there a way to use scalebox along with tabular.environment='longtable' when printing a long and wide xtable?  When I give both of them I get an error:  Running xelatex.exe on my_file.tex...failed

I am going make a table smaller in a paper which I am going to submit to a journal. I used \small but it does not make it small enough ?


I am trying to make my project a runnable jar but the problem is that the gui is not showing up. From the error in my cmd i tell it is something about my imageviews.  My project contains imageviews which are located in another folder than the sourcefoler. I have set the buildpath, but it still doesn't seem to work  This is where I add the images to the GUI:  String path = "./imageTest/";         File folder = new File(path);         File[] listOfFiles = folder.listFiles();         for (File file : listOfFiles) { <----- Line 51             ImageView imageView;             imageView = createImageView(file);             tile.getChildren().addAll(imageView);         }   The folder imageTest is added as a sourcefolder in the buildpath  This is the error I get when running the jar through cmd:  "Exception in Application start method Exception in thread "main" java.lang.reflect.InvocationTargetException         at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)         at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)         at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)         at java.lang.reflect.Method.invoke(Unknown Source)         at org.eclipse.jdt.internal.jarinjarloader.JarRsrcLoader.main(JarRsrcLoader.java:58) Caused by: java.lang.RuntimeException: Exception in Application start method         at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:917)         at com.sun.javafx.application.LauncherImpl.lambda$launchApplication$155(LauncherImpl.java:182)         at java.lang.Thread.run(Unknown Source) Caused by: java.lang.NullPointerException         at application.guifx.MainScreen.mainScene(MainScreen.java:51)         at application.guifx.MainApp.start(MainApp.java:37)         at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$162(LauncherImpl.java:863)         at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$175(PlatformImpl.java:326)         at com.sun.javafx.application.PlatformImpl.lambda$null$173(PlatformImpl.java:295)         at java.security.AccessController.doPrivileged(Native Method)         at com.sun.javafx.application.PlatformImpl.lambda$runLater$174(PlatformImpl.java:294)         at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)         at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)         at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191)         ... 1 more"   This is the MainApp  public class MainApp extends Application {     private Service service;     private Stage stage;     private ScrollPane root = new ScrollPane();      private MainScreen mainScreen;       public MainApp() {         service = Service.getService();         StorageInitializer.initStorage();      }      @Override     public void start(Stage primaryStage) throws Exception {         service = Service.getService();          stage = primaryStage;          mainScreen = new MainScreen(stage);          stage.setWidth(100);         stage.setHeight(100);          primaryStage.setWidth(1000);         primaryStage.setHeight(850);          Scene scene = mainScreen.mainScene();<----- Line 37          primaryStage.setScene(scene);         primaryStage.show();     }      public static void main(String[] args) {         launch(args);      }  }   To be clear... The program works when laucnhing through eclipse, but doesn't when I make it a runnable jar This is how the system looks when opening it from eclipse

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


For a collection $C$ define an object $b \in C$ iff $b$ is a class and $b \notin b$ and otherwise $b \in C$. Then we can decide any object whether it belongs to $C$. In Hungerford's Algebra p.2 it states in illustrating Gödel-Bernays axiomatic set theory that     Intuitively we consider a class to be a collection $A$ of objects such that given any object $x$ it is possible to determine whether or not $x$ is a member (or element) of $A$   Since it's possible to determine whether an object belongs to $C$, $C$ must be a class.  Then there is a paradox whether $C \in C$. How to avoid this in Gödel-Bernays axiomatic set theory.

I am not very big in mathematics yet(will be hopefully), naive set theory has a problem with , how do they defeat this sort of problem in mathematics? Is there a greater form of set theory than naive set theory that beats this problem? (Maybe something like superposition if is both or neither)?


Let $(G,\cdot)$ be a group and define the comutator as $[a,b] := aba^{-1}b^{-1}$ for every $a,b\in G$. About to prove that $[G,G] \leqslant_n G$, first i need to prove that is in fact a subgroup, wich is were i failed. My question is:     Given $a,b,c,d\in G$, find $x,y\in G$ such $[a,b]\cdot[c,d] = [x,y]$.   This is for proving that $[\,\cdot\,,\,\cdot\,]$ are closed at $[G,G]$. The otter statments wich defines a group i've allready check it, but they doesn't defines a group if the operation $\cdot$ wouldn't give me an element of $[G,G]$. Thanks for the help.  Mistakes. In fact, $[G,G]$ isn't the comutator as well, so $[G,G] {\require{cancel}\cancel{\leqslant}} G$, so, the product of the comutators isn't a comutator as well

It is suggested as an exercise in Serge Lang's book "Algebra" to show that the commutator subgroup $G^c$ of a group $G$ is a normal subgroup.   I'd like to do that but I am afraid I need help,   I think the first thing I need to figure out is how a general element in the commutator subgroup looks like, so that I can check that the defining condition for normality is satisfied.  That is, supposing for a moment that a general element in $G^c$ is denoted by $g$, I need to show that $aga^{-1} \in G^c,$ for all $a \in G$.  But here I get stuck, first because I am unsure how to write a general element in $G^c$ - a simple product in $G^c$ is of the form $xyx^{-1}y^{-1}aba^{-1}b^{-1}$ where $a,b \in G$. I cannot see a way to simplify this - I am sure there is one, but somehow I am blind today.  The second thing then is, even if one tries out the conjugation of a simple element like $xyx^{-1}y^{-1}$ in $G^c$, again not simplification offers itself easily I think .. what am I missing ?  An alternative would be to find a homomorphism of $G$ whose kernel is precisely $G^c$ - here I tried to think of this as a map $G \times G \to G$ but whatever I cook up is not a homomorphism.  Thanks for your hints !!


i have installed code blocks from Ubuntu software Center. When I create a new project and compile it, in the output window it say "permission denied". How must I run code blocks, or where should I place the project files to remove this error ?!

When I try to compile it says  sh: 1: /media/user/Linux/test/bin/Debug/test: Permission denied   I did not have this problem with Ubuntu 12.10   I have just started to use Ubuntu so....


Let's say that hypothetically we could travel faster than light. Would a ship travelling at lightspeed or faster than light travel create a time loop where it makes the same trip over and over again over the same period of time?

I'm new to physics and I was wondering if time loops (like those seen in the movies Groundhog Day or Edge of Tomorrow) possible?


Doesn't SHA-256 only take up to 512 bits for the input block? What happens if the input is really long?

I’m very interested how SHA-256 handles messages, but I’ve got 3 questions. (As I have already read in some answers before, SHA-256 is not directly performed on the message but on an array, thanks for that.)   In my understanding after padding the message to a multiple of 512 bit length, we put the message into a     64 entry message schedule array w[0..63] of 32-bit words   Is this an array with 64 elements, each allowed to be 32 bits long?     copy chunk into first 16 words w[0..15] of the message schedule array   But then I ask myself, if we have a message that is, for example 4096 bits long and we only fill the first 16 elements of the array with the original message, what happens to the other (4096-16*32 = 3584) 3584 bits of the message?    s0 := (w[i-15] rightrotate 7) xor (w[i-15] rightrotate 18) xor (w[i-15] rightshift 3)   What are the rightrotate and rightshift operators doing to the elements in the array?


My primary reason for hovering a tag is to learn more about the tag. But when you hover a tag, that isn't one of the options on the popup. It has a link to questions tagged with that tag (with very misleading text), and buttons for following the tag or ignoring it, but not for going to the tag wiki to learn more about it. Before the redesign, the popup had an "info" link which I used all the time.  Two things which I believe fit within one FR:   Change the text of the current link to questions tagged with that tag. The current text is "View tag" which is odd, since it takes you to a list of questions, not the tag wiki. Add a link to the tag wiki.

The new tag popup makes it easy to watch or ignore particular tags and shows the tag info excerpt. Here's one on EL&U:    However, the  contains a lot more information which helps users. Getting at that information is not obvious: you need to click the View tag link which provides a , and then click the Learn more... link.  The old tag pop-up used to include a link to the full tag info, and it appears that this was implemented as a result of a  which changed behaviour which was remarkably similar to what happens now.  Here's  to give the idea. The Info link showed the full tag info.    The current behaviour is a regression, breaking something which was previously fixed.  Could View tag in the new popup be changed to Other questions and a new More info link be included which gives easier access to the full tag info? Perhaps something like this...


I am using a OSX with Server App who bring a Mail service that have Postfix and Dovecot.  Now i am unable to send mails in my mail server, i am getting this error:  EF5CBCF65F      992 Thu Nov  3 11:49:28  teste@X.pt (connect to remote.X.pt[<IP>]:25: Connection refused)                                         X@gmail.com   And all my mails are being stack as i have notice through mailq.  After trying telnet, i notice that i was only able to connect to localhost, 127.0.0.1 and remote.X.pt, was not able to be seen from outside. I have an Static IP that is not blocked (I already check from a huge list i just have 1 block).   In Postfix main.cf i have my interfaces to all:  inet_interfaces = all   Then i made a dig mx and i receive this:  <<>> DiG 9.8.3-P1 <<>> mx remote.X.pt ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 11055 ;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 1 ;; QUESTION SECTION: ;;remote.X.pt. IN MX ;; ANSWER SECTION: remote.X.pt. 10800 IN MX0 remote.X.pt. ;; AUTHORITY SECTION: remote.X.pt. 10800 IN NS remote.X.pt. ;; ADDITIONAL SECTION: remote.X.pt. 10800 IN A 192.168.1.1 ;; Query time: 0 msec ;; SERVER: 127.0.0.1#53(127.0.0.1) ;; WHEN: Thu Nov  3 12:42:21 2016 ;; MSG SIZE  rcvd: 81   I already saw some fix's but till now no one have worked here, and i already add my server at DMZ just to see if was from the firewall, but it wasnt.   I am able to send mail from my local server without any outgoing mail, but if i use the same email on my mail server and my Mail app (client), it will goes to my ISP server without problem (right now i am getting an 550 error but at least i know that its there).   When i use another account just for forwarding mail purpose i receive that error of service. So how can i create an forwarding mail?   I have already search about it before but dont know how to set one, to use it to forward mails from local emails, to an external ISP mail server.   Any clue on how can i set and use a forwarding mail?  Sven thanks for the edit of my post i didnt notice!

This is a  about Connection Refused    We see a lot of questions to the effect      When I try to connect to a system I get a message      Connection refused      Why is this ?


I'm following  in trying to prove that Cayley's theorem emerges as a particular case of the Yoneda lemma. In case that article gets edited, here's the screenshot:  A couple of aspects in the proof are unclear:  In proving that the set of $G$-equivariant maps $\alpha_\ast:\mathcal C(\ast,\ast)\to\mathcal C(\ast,\ast)$ is a group, I'm not sure what the inverse of $\alpha_\ast$ is.  A (probably) related question: $X$ is the image of the unique object $\ast$ under $H^\ast$, i.e., $\mathcal C(\ast,\ast)$. $\text{Perm}(X)$ is the set/group of bijections from $\mathcal C(\ast,\ast)$ into itself. To show that all equivariant maps form a subgroup of this group, we need to show that each equivariant map $\alpha_\ast$ is a bijection from $\mathcal C(\ast,\ast)$ into itself. But I don't see why $\alpha_\ast$ has to be a bijection. $\alpha$ is just a natural transformation, not a natural isomorphism.  I'm a little confused about the this point from Wikipedia: "(2) the function which gives the bijection is a group homomorphism". What function is meant here? The function from the (dual version of the) Yoneda lemma $[\mathcal C,\textbf{Set}](H^\ast,H^\ast)\to\mathcal C(\ast,\ast)$ doesn't seem to be exactly the right function because its domain has elements that are natural transformations $\alpha$, but we want to construct a function from the set of $G$-equivariant maps, which have the form $\alpha_\ast$ for some natural transformation $\alpha$. So I suspect that the map that is meant is the composite $$\{\alpha_\ast: \alpha:H^\ast\to H^\ast\text{ is a nat. transf.}\}\to \{\text{nat. transf. } \alpha:H^\ast\to H^\ast\}\to \mathcal C(\ast,\ast)$$ where the first map is a "natural" bijection (natural in the non-technical sense). But if so, I don't really see why this is a group homomorphism. If we call this composition $f$, then we need to show that $f(\beta_\ast\circ\alpha_\ast)=f(\beta_\ast)\circ f(\alpha_\ast)$ or equivalently $\beta_\ast(\alpha_\ast(1_\ast))=\beta_\ast(1_\ast)\circ\alpha_\ast(1_\ast)$. I don't really see why this is true, although this must be something easy.

I came across the statement that Yoneda-lemma is a generalization of Cayley`s theorem which states, that every group is isomorphic to a group of permutations.  How exactly is Yoneda-lemma a generalization of Cayley`s theorem? Can Cayley's theorem be deduced from Yoneda lemma, is it a generalization of a particular case of Yoneda, or is this instead, a philosophical statement?  To me, it seems that Yoneda embedding is more canonical than Cayley's theorem because in the latter you have to choose whether the group acts from the left or from the right on itself. But maybe this is an optical illusion.


I heard that expression along with its derivatives so many times, in movies or otherwise, but I can't get it grammatically, meaning, does it stand for a complete sentence like "I will fuck you!" or "I want to fuck you!"? Or what?  Is it an imperative construction, or part of some other type of sentence with material deleted?  NB: This question is NOT about the meaning of this phrase (amply addressed in other questions on this site, such as ). It is about the structure of the phrase from a grammatical perspective, along with the common meaning of the expression.

This conversation is from "Youth in Revolt" movie.    A boy named Nick met his colleague, a girl, in a music shop while purchasing a DVD and after a little talk, her boyfriend hugged her from behind in front of Nick. Then the girl chuckles and says: "Chad, fuck you". He replies — "Oh, fuck you, you love it."  Obviously, fuck here doesn't mean "sexual intercourse" or "destroy or ruin" or "make someone angry", which are meanings from Oxford Dictionary online.  What is the meaning of fuck you here?


I want to turn a iPhone in to a Android OS phone. Is this possible?

Many people want to try/use Android without buying a new Android phone.  How can I install Android on my current phone or device running Nokia Symbian, Maemo, or MeeGo; Microsoft Windows Mobile or Windows Phone 7/8/10; Apple iOS (iPhone); RIM's BlackBerry OS; Palm's WebOS; Samsung's Bada; HP's WebOS; Mozilla's Firefox OS; or other phone / operating system?


I have recently bought 2 Dell monitors (S2419H) and would like to use them as two additional screens with my 13 inch TouchBar MacBook Pro. However, when I connected both screens using an HDMI/USB C adaptor, the two monitors displayed the same thing i.e. only 2 desktop screens are being shown. I have  tried fixing this on the arrangement tab but only 2 screens are being shown there. Is there a way I can have 3 distinct screens?

I'm trying to hook up dual monitors (Samsung CF390) to my MacBook Pro, but when I do, I only have the desktop image projecting on both screens. When I go into Settings > Display, the "Arrangement" option isn't available.  I have both monitors' HDMI cables running through 1 USB-C to HDMI adapter. (The adapter has two ports.)  Is the solution to this problem having two adapters? My thinking is even though the adapter has 2 ports, the MacBook hardware or software can't Fully make use of both displays.   What can I change to get three total displays working on macOS High Sierra (10.13.x)?


I've been playing with a slider/slide implementation for my site. But don't know how to configure jQuery properly.  My research suggests that this is an issue with the implementation of a jQuery version, but there's conflicting information on how to resolve the problem in the various documentation. I'm aware of both jquery_update and jquery_plugin modules. My current setup have manually loaded libraries for jquery.cycle and Flexslider per their individual documentations. Earlier posts suggest this was a jQuery version conflict.  The issue I have is that the slideshow only cycles in the preview on the page view of the slider. It doesn't cycle in the block view, and it doesn't cycle when it's placed on my page. This the case with both Flexslider and with Views Slideshow. I have the correct modules and libraries, I just don't understand why it works in preview and not when placed on the page.  This post addresses a similar issue , but doesn't really elaborate on how the jquery update conflicts, or how to solve the problem. This post was was flagged as a duplicate so I am trying to articulate what I think I need help with here.   I have searched the documentation on Views Slideshow and Flexslider, and I haven't found an obvious solution to the problem, or a definitive way to address the problem. What seems to be the case is that this is a jQuery versioning issue, where for some reason the javascript isn't initialized from the block itself, but only a page view. I don't know enough about the behavior of javascript in Drupal to understand exactly why one will make the js call, and the other won't?

My block is not working for the flexslider: The images are not appearing, but the view preview does work.  I don't know if it is relevant, but a similar problem would happen with just a slideshow view, although one image would appear and it would not cycle.  Could jQuery be a problem?  The following is the actual page with the block that is not showing any images.        The following is the view preview, which works.


In a few posts, most say INSTR is faster. (Of course, it depends on the situation.)  In the following cases, I wonder whether I should continue to use INSTR or how to optimize it.  CASE 1.  SELECT * FROM TB1, TB2 WHERE TB1.PKID = TB2.P_PKID  The result is displayed immediately when you inquire.  CASE 2.  SELECT * FROM TB1, TB2 WHERE TB1.PKID = TB2.P_PKID AND DBMS_LOB.INSTR(TB2.CONTENTS, 'KEYWORD')>0  But, it takes 10 seconds to search the contents(CLOB Type) using INSTR.  CASE 3.  SELECT * FROM TB1, TB2 WHERE TB1.PKID = TB2.P_PKID AND TB2.CONTENTS LIKE '%KEYWORD%'  Using LIKE takes 22 seconds.  The total number of data is about 100,000.   I just wonder if I should continue to use INSTR, or is there another way?

Is there an Oracle equivalent to MS SQL's full text search service?  If so, has anyone implemented it and had good / bad experiences?


I installed software from Nuance recently, and they surreptitiously installed a program called FlexNet Connect (even with a custom install). FlexNet Connect does not provide useful information on its site, like architecture or security architecture documents.  shows its running as a service under NT AUTHORITY/SYSTEM and its image is hidden in C:\ProgramData. It also looks like its Adobe Air based, and Adobe is renowned for its insecure software. Finally, all it has done is served ads.  I think I would like to remove FlexNet Connect. There is no Uninstall option for the adware in Programs and Features | Uninstall. Additionally, it looks like its .  My question is, how do I completely remove FlexNet Connect software from this machine?    I still remember the days when Adobe used to distribute that Macrovision crap with its software. Macrovision would run as a driver, and it had a big security hole that went unpatched for years (as if Adboe needed help in making a machine insecure). As such, neither Adobe software nor Macrovision software are allowed on any machines under my control.

Do you know how can I remove this unwanted software? Status line says copyright Acresso Software and or InstallShield. From the folder in ProgramData I understand it is version 11.


I want to remove the News app from my computer. I tried to remove it myself:  dsenableroot su - root sudo rm -rf /Applications/News.app   "Operation not permitted"  It appears I no longer in control of my computer.  Can somebody help me pull this app out of my machine?

There are some preinstalled apps that came with my laptop that I know I wil never ever use.   Apps like "Notes", "Stickies", "Game Center", etc.. that were preinstalled in my Macbook Pro are apps that I don't plan on ever using and it's taking up too much space in my Application Folder.  Are there any ways to remove them? Please note that I have already tried dragging it to the Trash bin, but it won't even go to the Trash bin. It' just stuck in my computer forever.


I know initially it seems like only George R. R. Martin or a magician can answer my question.  What am I asking actually is, are the names and surnames used in the books real? Are "Theon" and "Tywin" real names that people use in some country? Are there real family names like Lannister or Stark?  Since Westeros seems a lot like medieval Europe, it seems to me that names for people and places should be more Germanic than Italian. Am I right?

Azor Ahai is some mythical hero, who may or may not coincide with other mythical heros that are supposed to be born and save us from the eternal night (which is dark and full of terrors, if we are to believe Melisandre).  But I'm interested in the origins of the name, here, in our world. More specifically because in Hebrew "Azor Ahai" means (albeit ungrammatically) "Help my brothers", or if you transliterate it differently you'd get "The Living Help".   Since writers often take meaningful names to be terms from other languages (and mangle them a bit), I can't help but wonder Did GRRM reveal the origin of the name "Azor Ahai" at some point?


Sounds strange because and indeed it is. I came here to ask for this because I am lost for words, in a negative way. The company I work for, created a new brand name. Let's call the company Foo and the brand name Bar for the example. So I searched for Bar in Google and obviously, the results were related to Bar and Foo. So far so good.  What made me scratch my head, was that there were weird results. My company sells cosmetics. We got some results for Bar that were related to:  leather waller snickers how to find a specific cemetery (??) cell phone screen covers some kinky stuff  Most of the results are like randomurl.tk Some of them didn't exist at that moment. Some others, when I entered, I faced a site that was a bunch of links, with really irrelevant stuff. Some of these came as result showing Foo, others Bar, others Foo Bar. Title, Meta description keywords are totally unrelated. It really looks like a bot that gathers random data along with spam links.  The weirdest part is that some of the urls are the website along with a path that was the exact permalink of the product in our webpage, with a wishlist in the end if I recall right.  So here comes the question: What on earth is this? I suspect that this is a sabbotage attempt since it is really targetted and also follows the exact opposite rules of good SEO. I might be paranoid eventually, but hey, I have to ask.  If someone wants to sabbotage the SEO a webpage, or a brand name, relating the keyword with spam, does Google fall for it? I mean, there is a legit page, with great content, SEO optimized, seen results for some stuff, but when it comes to the cosmetics, it's like we do not exist. Does google relate the website as spam due to other websites that use maliciously the keywords of the company name and brand?  If so, what do you suggest us to do?

I have read a couple of articles about negative/black SEO. They were explaining that important part of it is creating web sites with "bad" content that "stink" to Google. Back links from these sites are consequently penalized by Google and target sites receive negative bonus to their ranking.  However, I had a little argument with my friend today, who is from my point of view an experienced web developer and SEO optimizer.  He told me that this negative SEO and penalized sites is complete nonsense. He gave me an example that there is no problem for a company to create link farm of "bad links" that would be imposible for any tool to block. So if negative SEO was possible, there would be many big internet companies with sites ruined by this SEO.   So I am asking you, because you always gave me good advice, is it fiction or fact?


I want it to be something like 90% opaque, so the icons are easier to see on light-colored themes.

This command  gsettings set org.gnome.shell.extensions.dash-to-dock transparency-mode    can have these values: 'FIXED' 'DEFAULT' 'DYNAMIC' 'ADAPTIVE'.  But none makes the dock bar completely transparent, that is, only the icons are visible.  any ideas?


I am new to QGIS, but have to find the distance between centroids of NJ municipalities (which I have as a shapefile) and the nearest road sign which is also its own shapefile, along the roads of the state. I have three shapefiles: one road shapefile, and two point shapefiles and my goal is to find the road distance between points of the two point shapefiles. I have tried the RoadGraph plugin but I do not want to have to manually click each point since I have to know the nearest sign to each centroid first.

I'm looking for a way to calculate the shortest path from addresses to subway stations via a network of roads.  I have the , however, the addresses and subway stations are point layers that do not overlap with vertices in the roads layer.  In QGIS, is there a way to calculate the shortest distance from the address/subway station points to the roads, create vertices at those locations, then calculate the shortest distance via the roads network?   black squares - addresses white circles - subway stops gray lines - roads


Dear Convex Optimization Experts,  My question is related to this post: , but not really same, I think, as I have a constraint. Apologies if it is obvious to extend the answer.   So, I am seeking a proximal operator $\textrm{prox}_{\lambda f}(x)$ of this function $$f(x) = I\left\{x \in C \right\} \ ,$$ $$C = \left\{x : \lVert x \rVert_{\infty} \leq \gamma \right\} \ ,$$ where $x \in \mathbb{R}^{n \times 1}$, $I\left\{\cdot \right\}$ is an indicator/characteristic function, $\gamma \in \mathbb{R}^{n \times 1}$, and the constraint $\lVert x \rVert_{\infty} \leq \gamma$ is element-wise.   EDIT: The desired constraint is: $$C = \left\{x : |x_i| \leq \gamma_i \right\} \ ,$$

What is the Orthogonal Projection onto the $ {\ell}_{\infty} $ Unit Ball?  Namely, given $ x \in {\mathbb{R}}^{n} $ what would be:  $$ {\mathcal{P}}_{ { \left\| \cdot \right\| }_{\infty} \leq 1 } \left( x \right) = \arg \min_{{ \left\| y \right\| }_{\infty} \leq 1} \left\{ {\left\| y - x \right\|}_{2}^{2} \right\} $$  I managed to get an answer using the . Yet I would be happy to see if someone can derive the answer directly.  Thank You.


I want to export results of my Kriging calculation to raster or some other format. My aim is to take this converted file and intersect it with another SpatialPointDataFrame (location of the point doesn't have to be the same, so that is the reason of conversion). The goal is equivalent of "Extract values To Points" in ArcGIS - thus, merge information from kriging and another SPDF for one locations.   For second part, I imagine just to use raster::intersect(krig, SPDF). But how to get raster data for my Kriging? I tried to raster::rasterize  r <- raster(ncols = length(ux), nrows = length(uy))  # length(ux), length(uy) krig.rst<-rasterize(krig.est, r, "var1.pred")   and   krig.rst<-rasterize(krig.est, r, "var1.pred", fun = function(x, ...) c(min(x))   The raster seems to be calculated, but I can't display it.  Please, is the problem in my raster dimension (nrow, ncol, ncell)? How can I assigned it? My first thought was that 1 cell of matrix (from Kriging) will correspond to 1 pixel of raster with assigned value, but I am obviously wrong.    Long reproductible exemple adapted from here:   library(sp) library(gstat) library(RColorBrewer)  # https://rpubs.com/nabilabd/118172 # packages for manipulation & visualization suppressPackageStartupMessages({   library(dplyr) # for "glimpse"   library(ggplot2)   library(scales) # for "comma"   library(magrittr) })  data(meuse)  # create spdf meuse.spdf<-meuse  # convert to spdf coordinates(meuse.spdf) <- ~ x + y    # calculate voronoi tesselation - will be needed to create underlying point data voronoipolygons = function(layer) {   require(deldir)   crds = layer@coords   z = deldir(crds[,1], crds[,2])   w = tile.list(z)   polys = vector(mode='list', length=length(w))   require(sp)   for (i in seq(along=polys)) {     pcrds = cbind(w[[i]]$x, w[[i]]$y)     pcrds = rbind(pcrds, pcrds[1,])     polys[[i]] = Polygons(list(Polygon(pcrds)), ID=as.character(i))   }   SP = SpatialPolygons(polys)   voronoi = SpatialPolygonsDataFrame(SP, data=data.frame(dummy = seq(length(SP)), row.names=sapply(slot(SP, 'polygons'),                                                                                function(x) slot(x, 'ID')))) } meuse.voro <- voronoipolygons(meuse.spdf)     # create underlying grid s.grid <- spsample(meuse.voro, type = "regular", n = 6000)  # calculate kriging  # create variogram lzn.vgm <- variogram(log(zinc)~1, meuse.spdf) # calculates sample variogram values  lzn.fit <- fit.variogram(lzn.vgm, model=vgm(1, "Sph", 900, 1)) # fit model  plot(lzn.vgm, lzn.fit) # plot the sample values, along with the fit model  # calculate kriging lzn.kriged <- krige(log(zinc) ~ 1, meuse.spdf, s.grid, model=lzn.fit)   # extract the unique x and y locations in the grid ux<-unique(coordinates(lzn.kriged)[,1]) uy<-unique(coordinates(lzn.kriged)[,2])  # extract the predicted values and format var1.pred into a matrix of gridded values predmat3 <- matrix(lzn.kriged$var1.pred, length(ux), length(uy))  # display the data  filled.contour(x = seq(0,1, length.out = nrow(predmat3)),                y = seq(0,1, length.out = ncol(predmat3)),                z = predmat3,                col = brewer.pal(6,"Purples"), nlevels = 5)

I am trying to do kriging by gstat package through R.   Here is my Code:  krg<-krige(var ~ 1,data,grid,model=vgm,nmax=30)   But each time I recive this warning:  1: In predict.gstat(g, newdata = newdata, block = block,  ... :    Warning: Covariance matrix (nearly) singular at location [1,4501,0]: skipping...   and when I try to plot it by spplot this error appears:  Error in seq.default(zrng[1], zrng[2], length.out = cuts + 2) :    'from' cannot be NA, NaN or infinite In addition: Warning messages: 1: In asMethod(object) :   complete map seems to be NA's -- no selection was made 2: In min(x) : no non-missing arguments to min; returning Inf 3: In max(x) : no non-missing arguments to max; returning -Inf   Here is the full code: You can download my data through this link:  and here is my full code:  library(gstat)                                          library(sp) library(raster)  coordinates(Mydata) <- ~East + North proj4string(Mydata) <- CRS("+proj=utm +zone=10+datum=WGS84") ext <- as(extent(Mydata), "SpatialPolygons") r <- rasterToPoints(raster(ext), spatial = TRUE) proj4string(r) <- proj4string(Mydata)  v1 <- variogram(cpue_female ~ 1, Mydata) vgm_mod_omni <- vgm(psill = 0.0003, model = "Mat", range = 50000, nugget = 33, kappa = 0.5) G1 <- krige(cpue_female ~ 1, Mydata, r, vgm_mod_omni, nmax = 30) gridded(G1) <- TRUE spplot(G1)


I was doing the donut tutorial and the sprinkles were rendering in the viewport but not the final. Any idea why? Edit: This is my blend file.

I just started learning Blender, so I'm following the donuts tutorial from Blender Guru. Unfortunately, I'm stuck at part 7 on rendering Sprinkles.  My problem is, the Sprinkles is visible in my viewport :    However, when I render it, the sprinkles are gone :    My Blender file can be downloaded .  Any help is appreciated. Thank you.


While obtaining the density of states of photons one multiple it with 2 for two polarization states,  My question is that the whole calculation is based on quantum phenomena of light so why one uses wave phenomena (Polarization) in here.

I understand how one associates the spin of a quantum particle, e.g. of a photon, with intrinsic angular momentum. And in electromagnetism I have always understood the polarization of an EM wave as the oscillations of the E and M field, not necessarily being  aligned with the direction of propagation of the wave.     Questions:   But when one talks about the polarization of a photon in Quantum Mechanics, how does it really differ from its spin?  Are they somehow related and what's the physical idea behind photon polarization in contrast to photon-spin? Feel free to use mathematical reasonings as well if you see it fit!


I was messing around with some matrices and found the following result.      Let $A_n$ be the $(2n) \times (2n)$ matrix consisting of elements $$a_{ij} = \begin{cases} 1 & \text{if } (i,j) \leq (n,n) \text{ and } i \neq j \\ 1 & \text{if } (i,j) > (n,n) \text{ and } i \neq j \\ 0 & \text{otherwise}.  \end{cases} $$    Then, the determinant of $A_n$ is given by $$\text{det}(A_n) = (n-1)^2.$$   Example: $$A_2 = \begin{pmatrix} 0 & 1 & 0 & 0 \\ 1 & 0 & 0 & 0 \\ 0 & 0 & 0 & 1 \\ 0 & 0 & 1 & 0 \end{pmatrix}, A_3 = \begin{pmatrix} 0 & 1 & 1 & 0 & 0 & 0 \\ 1 & 0 & 1 & 0 & 0 & 0 \\ 1 & 1 & 0 & 0 & 0 & 0 \\ 0 & 0 & 0 & 0 & 1 & 1 \\ 0 & 0 & 0 & 1 & 0 & 1 \\ 0 & 0 & 0 & 1 & 1 & 0 \\ \end{pmatrix},$$ with det$(A_2)$ and det$(A_3)$ being $1$ and $4$ respectively. I was wondering if anybody could prove this statement for me.

This question aims to create an ""  of numerous questions that ask about determinants of specific matrices (I may have missed a few):              The general question of this type is  Let $A$ be a square matrix of rank$~1$, let $I$ the identity matrix of the same size, and $\lambda$ a scalar. What is the determinant of $A+\lambda I$?  A clearly very closely related question is  What is the characteristic polynomial of a matrix $A$ of rank$~1$?


Is that proved that breaking ECDSA (Elliptic Curve Digital Signature Algorithm) as hard as solving ECDLP(Elliptic Curve Discrete Logarithm Problem)?

Is there proof that the DSA construction, also used by ECDSA, is secure assuming that discrete logarithms in the relevant group representation are difficult?


I am trying to compute this quantity. It seems we have to use Stirling’s formula but I don’t really succeed... Although trying to compute the quantity with a large n it seems to converge to $e^{1/2}$. Thank you for you help

$\lim_{n \to \infty}\left({^n\mathrm{C}_0}{^n\mathrm{C}_1}\dots{^n\mathrm{C}_n}\right)^{\frac{1}{n(n+1)}}$ is equal to: a) $e$ b) $2e$ c) $\sqrt e$ d) $e^2$  Though it looks really innocent at first sight, it certainly isn't. Attempt: It's $\infty^{\infty}$ form. I had tried taking the product raised to the power $\frac{1}{n(n+1)}$ as function $f(n)$. Then I took logarithm of both sides to see if things simplifying.  Even after factoring out the extra factorials it wasn't easy. Note that ${^n\mathrm{C}_x} = \binom{n}{x}$.


I read on Wikipedia that electrons can be created through beta decay of radioactive isotopes and in high-energy collisions, for instance when cosmic rays enter the atmosphere. Also, that they can be destroyed using pair annihilation. We also know that charge is a physical property which can be associated with electrons. My question is why can't charges be created or destroyed if electrons can?

Probably a silly question, but something that came to mind yesterday. I couldn't find anything when searching.  Why is there an Energy mass equivalence principle but not an Energy charge equivalence principle?   In other words, why do our field theories have a Gauge invariance which allow for charge conservation, but not mass conservation, or why is it that charge has escaped from being a term in the energy mass equivalence? Is it just because we have observed these to be the case and made our field theories around this, or because that's just how the mathematics works out?


Ubuntu Bionic 18.04 SoftwareUpdater this morning installed updates including a new kernel version 4.15.0-24-generic #26-Ubuntu. Now when the system boots the screen displays the content of some log instead of the login prompt.  The log file is displayed after the normal red dots phase, except that there is a long pause after the 4th dot becomes red and the fifth dot never becomes red. Suddenly this log is displayed. Almost everything in it is [ OK ].  The last 3 lines of this log read  [ OK ] Started irqbalance daemon [ OK ] System Logging Service. [ OK ] Started GNOME DisplayManager. Dispatcher Service....upport.hanges.pp link was shut down.    Further up is one non-OK line that might be related, but later in the line there is [ OK ]. Maybe the "Plymouth BootScreen" it refers to is what I am seeing.  [   .] A start job is running for Hold until boot process finishes up (28s / no limit)[ OK ] Started Show Plymouth BootScreen.   I tried booting the previous kernel but the same thing happens.  I am unable to scroll up to see the beginning of this log.  How can I get my system to boot properly and show the login screen?  I can ssh into the system so if I know what to change to fix this, I should be able to do it.  This is the latest in a depressingly long list of Ubuntu software updates that have ****ed up my system. It's no wonder users are reluctant to install updates.  I found , opened 6/30, which matches this problem.  EDIT:  is a different problem with similar symptoms.  has matching symptom and cause.

I'be been running 18.04 since a clean SSD install on the day of it's official release, without issues. Power on to login was seconds (max 10)  Then, I did a regular upgrade this morning:  $ sudo apt update && sudo apt dist-upgrade   The packages installed/upgraded were:  Install: linux-headers-4.15.0-24:amd64 (4.15.0-24.26, automatic), linux-headers-4.15.0-24-generic:amd64 (4.15.0-24.26, automatic), linux-modules-extra-4.15.0-24-generic:amd64 (4.15.0-24.26, automatic), linux-modules-4.15.0-24-generic:amd64 (4.15.0-24.26, automatic), linux-image-4.15.0-24-generic:amd64 (4.15.0-24.26, automatic) Upgrade: gnome-control-center-data:amd64 (1:3.28.1-0ubuntu1.18.04.1, 1:3.28.1-0ubuntu1.18.04.2), linux-headers-generic:amd64 (4.15.0.23.25, 4.15.0.24.26), gnome-control-center:amd64 (1:3.28.1-0ubuntu1.18.04.1, 1:3.28.1-0ubuntu1.18.04.2), linux-image-generic:amd64 (4.15.0.23.25, 4.15.0.24.26), linux-signed-generic:amd64 (4.15.0.23.25, 4.15.0.24.26), gnome-control-center-faces:amd64 (1:3.28.1-0ubuntu1.18.04.1, 1:3.28.1-0ubuntu1.18.04.2), linux-generic:amd64 (4.15.0.23.25, 4.15.0.24.26)   I rebooted once the upgrade had completed, and noted a 2-3 minute delay on the Ubuntu loading/splash screen (prior to login) (without any progress/activity indicated on the dots).  I powered off and tried to boot again, but am getting this delay consistently now. Also close down is much slower too.  Update #1 (2018-07-03): Analysis on systemd:  $ sudo systemd-analyze blame 3min 53.073s plymouth-quit-wait.service     2min 20.699s snapd.seeded.service          49.949s snapd.service           6.186s NetworkManager-wait-online.service           1.148s dev-sda2.device           1.098s plymouth-start.service   Showing that plymouth-quit-wait.service (which I now believe is related to the Ubuntu loading/splash screen) and snapd.seeded.service were by far the longest running services to initiate. So I compared the times before the dist-upgrade and after:  $ journalctl -u plymouth-quit-wait.service --since today -- Logs begin at Fri 2018-04-27 13:01:30 BST, end at Tue 2018-07-03 12:38:05 BST. -- Jul 03 04:15:43 user-laptop systemd[1]: Starting Hold until boot process finishes up... Jul 03 04:15:46 user-laptop systemd[1]: Started Hold until boot process finishes up. -- Reboot -- Jul 03 04:21:17 user-laptop systemd[1]: Starting Hold until boot process finishes up... Jul 03 04:24:52 user-laptop systemd[1]: Started Hold until boot process finishes up.   Before the upgrade plymouth-quit-wait.service took 3 seconds. After the upgrade it took 3 minutes 35 seconds  $ journalctl -u snapd.seeded.service --since today -- Logs begin at Fri 2018-04-27 13:01:30 BST, end at Tue 2018-07-03 12:42:14 BST. -- Jul 03 04:15:43 user-laptop systemd[1]: Starting Wait until snapd is fully seeded... Jul 03 04:15:43 user-laptop systemd[1]: Started Wait until snapd is fully seeded. -- Reboot -- Jul 03 04:22:47 user-laptop systemd[1]: Starting Wait until snapd is fully seeded... Jul 03 04:24:49 user-laptop systemd[1]: Started Wait until snapd is fully seeded.   Before the upgrade snapd.seeded.service took 0 seconds. After the upgrade it took 2 minutes 2 seconds.  Update #2 (2018-07-06): This morning's boot saw the return of the delay. So I guess we're still waiting for the kernel/plymouth/snapd update.  Update #3 (2018-07-12): The problem seems to be resolved, but I didn't see any update to snap or plymouth, and I'm still running 4.15.0-24 kernel. So I'm not sure which package update fixed the problem, or if it just resolved itself somehow. Reading the bug updates on launchpad it's unclear to me what was done (or is being done) to what package/s. If anyone can clarify that would be very useful.


Sorry for the newbie question, but I have been trying to resolve the problem of citations not showing up with texstudio. Below is a sample of my tex code \documentclass[12pt,a4paper]{article} \usepackage{graphicx} \usepackage[margin=1in]{geometry} \usepackage[table,xcdraw]{xcolor} \usepackage{float} \usepackage[utf8]{inputenc} \usepackage[english]{babel} \usepackage{chemfig} \usepackage[backend=biber,style=mla]{biblatex} \restylefloat{table}   \bibliography{EnzymeLabCitation} %opening \title{Sample Title} \author{Me} \date{}  \begin{document}     This is an example sentence with citation \cite{Polysaccharides}     \printbibliography \end{document}  with the following in the file EnzymeLabCitation.bib @misc{Polysaccharides, month = {mar}, title = {{Polysaccharides}}, url = {https://chem.libretexts.org/@go/page/17529}, year = {2016} } @misc{Starch_Iodine, month = {mar}, title = {{Starch and Iodine}}, url = {https://chem.libretexts.org/@go/page/383}, year = {2020} } @misc{Ololade2021, author = {Ololade, Akinfemiwa and Thiruvengadam, Muniraj}, booktitle = {Startpearls Publishing}, title = {{Amylase}}, url = {https://www.ncbi.nlm.nih.gov/books/NBK557738/}, urldate = {2021-03-21}, year = {2021} } @misc{Amylase, booktitle = {Britannica}, publisher = {Britannica}, title = {{Amylase}}, year = {2020} } @incollection{Kaphalia2019, abstract = {Advanced stages of chronic pancreatitis and pancreatic cancers (PCs) are very serious diseases with very poor prognosis. Therefore, identification of reliable and specific biomarker(s) at early stages of the diseases could be key to their early prevention and therapy. In this chapter, currently used and putative biomarkers of acute and chronic pancreatitis and PC are summarized. Total serum lipase and/or amylase are most widely used biomarkers of acute pancreatitis; lipase assay being more sensitive and specific than that of amylase. Imaging technologies provide key support for the diagnosis of both acute and chronic pancreatitis. Biomarkers of chronic pancreatitis are poorly developed and remain challenging because of impaired secretory components of exocrine pancreas. The focus of future clinical diagnosis of chronic pancreatitis and PC lies in identification of biomarkers using omics and microRNA arrays along with imaging technologies in well-defined experimental models and their validation in patients diagnosed with various stages of chronic pancreatitis and PC.}, author = {Kaphalia, Bhupendra S}, doi = {https://doi.org/10.1016/B978-0-12-814655-2.00019-0}, editor = {Gupta, Ramesh C B T - Biomarkers in Toxicology (Second Edition)}, isbn = {978-0-12-814655-2}, keywords = {Acute pancreatitis,Chronic pancreatitis,Diagnostic biomarkers,Functional biomarkers,Pancreatic cancer}, pages = {341--353}, publisher = {Academic Press}, title = {{Chapter 19 - Early Biomarkers of Acute and Chronic Pancreatitis}}, url = {https://www.sciencedirect.com/science/article/pii/B9780128146552000190}, year = {2019} } @misc{Williams2019,     author = {Williams, John},     booktitle = {Pancreapedia: Exocrine Pancreas Knowledge Base},     doi = {10.3998/panc.2019.02},     title = {{Amylase}},     url = {https://www.pancreapedia.org/molecules/amylase-2},     urldate = {March 21st, 2021},     year = {2019} }  With this, the document simply shows the word Polysaccharides instead of the citation, and the title 'Works Cited' does show up, but not the sources. I have been trying to run it in overleaf, and no luck either. I am quite confused and would appreciate all help (I am using Texstudio as the main text editor).

I'm trying to use a bibliography created using BibDesk in my LaTex document. To this extend I have the following (simplified) document:  \documentclass[12pt]{article} \usepackage{fontspec} \usepackage[style=mla,backend=biber]{biblatex} \addbibresource{Bibliography.bib} \setmainfont{Times New Roman}  \begin{document}  Pulitzer Prize-winning \autocite{Pulitzer:2017} novel \emph{The Underground Railroad} \autocite{Whitehead:2016}.   \printbibliography \end{document}   Then I first run XeLaTeX, then Biber, then XeLaTeX twice again. The problem now is that my bibliography for some reason only displays book references, no article or misc references. Also, there is more whitespace between the references than one expects.  Switching to normal LaTex instead of XeLaTeX didn't fix the problem.  How can I solve this issue?  My bibliography is:  @misc{Pulitzer:2017,     Date-Added = {2017-05-14 12:18:29 +0000},     Date-Modified = {2017-05-14 12:27:09 +0000},     Howpublished = {\url{http://www.pulitzer.org/prize-winners-by-year/2017}},     Title = {2017 Pulitzer Prizes}}   @book{Whitehead:2016,     Author = {Whitehead, Colson},     Date-Added = {2017-05-14 11:51:16 +0000},     Date-Modified = {2017-05-14 13:45:53 +0000},     Id = {UBL{\_}ALMA21286889210002711},     Isbn = {9780385542364},     Keywords = {PS3573.H4768; PS3573.H4768 U53 2016; Underground Railroad -- Fiction; Fugitive slaves -- United States -- Fiction; United States -- History -- 19th century -- Fiction; 1800-1899; 1800-1899},     N2 = {"Cora is a slave on a cotton plantation in Georgia. When Caesar, a recent arrival from Virginia, tells her about the Underground Railroad, they decide to take a terrifying risk and escape. Though they manage to find a station and head north, they are being hunted. Their first stop is South Carolina, in a city that initially seems like a haven. But the city's placid surface masks an insidious scheme designed for its black denizens. And even worse: Ridgeway, the relentless slave catcher, is close on their heels. Forced to flee again, Cora embarks on a harrowing flight, state by state, seeking true freedom." --},     Publisher = {New York : Doubleday},     Title = {The underground railroad : a novel},     Ty = {BOOK},     Year = {2016}}


In the option table for  there is a column called 'Price' and a column called 'Bid' and a column called 'Ask'.  If I wish to buy a call option, I need to pay a premium. Which column is the premium I would pay? Is it the 'Price'? But isn't the 'Price' supposed to be mid-way between the 'Bid' and 'Ask'? Why wouldn't it be?

In my online brokerage account, I want to buy a particular stock and I see the following:  Bid:  13.20 x200           Ask:  13.27 x1,000   the current stock price is 13.22.   Can someone explain what the bid and ask prices mean relative to the current price?  If I buy 1000 shares, why would I pay more?


I have auto generated 1 million page website. Pages are Something like  (Feel fee to remove the URL if it is against SE TOC)....... Now website is almost two years over. And I received around 5000 organic views per month. There is no increase of traffic last 6 month... I mean traffic is almost same in last 6 month. The questions I have.........  Even it has one million pages Google indexed only around 40,000 pages still. (Yes, I have submitted multiple site maps) Why Google not indexed other pages even after two years gone?  If I update (all pages will be updating), will Google notice that I have updated all pages? If not what can I do about it?  5000 organic views per month is not enough to just cover the hosting fee. So I need to increase traffic little bit. Is there anything can I do to increase traffic which is not in the  ? I asked this question because I can't apply most of the points in above question because this is a auto generated  content.

This is a general, community wiki  question and answer pair intended to address any questions   concerning the reasons a site or specific site contents do not appear   in search engine results.      If your question was closed as a duplicate of this question and you   feel that the information provided here does not provide a sufficient   answer, please open a discussion on .   My site (or specific pages on my site) is not appearing in search engine results.  Why isn't my content indexed and what can I do about it?


I  have a  I use it with a mouse connected to USB thanks to . For some time with my mouse, I can no longer scroll through the pages of browsers like Firefox or Chrome. Rather than scrolling the text from top to bottom or vice versa, it selects the text for me! I can no longer also do a copy / paste in the web pages, it selects but without displaying "copy / paste" I reset my tablet but it doesn't change anything. I have tried with a bluetooth mouse and have the same problem. The funny thing is that when I take control of my tablet with my computer and with teamviewer I use my computer mouse! Well it works. I can scroll web pages through my computer. An idea ? Thank you

I have a  I use it with a mouse connected to USB thanks to . For some time with my mouse, I can no longer scroll through the pages of browsers like Firefox or Chrome where another browser. Rather than scrolling the text from top to bottom or vice versa, it selects the text for me! I can no longer also do a copy / paste in the web pages, it selects but without displaying "copy / paste" I reset my tablet but it doesn't change anything. I reset my tablet by following  but it doesn't change anything. I changed the adapter, tried with another mouse, with a bluetooth mouse but it's the same :( I sent my tablet to the after-sales service 3 times for this problem but it came back each time as repaired but the problem is still present. The funny thing is that when I take control of my tablet with my computer and with teamviewer I use my computer mouse! Well it works. I can scroll web pages through my computer. An idea ? Thank you


I am struggling with this left outer join with multiple conditions in LINQ.  My initial SQL statement is as follows. SELECT DISTINCT [Product].[prod_id],     [Product].[brd_id],     [Product].[prod_brdId],     [Size].[size_id],     [Size].[size_sort],     [Bin].[bin_rack],     [Bin].[bin_alpha]      FROM [Proddetails]   JOIN [Prodcolor]   ON [Proddetails].[pcl_id] = [Prodcolor].[pcl_id]      JOIN [Product]   ON [Prodcolor].[prod_id] = [Product].[prod_id]      JOIN [Size]   ON [Proddetails].[pdt_size] = [Size].[size_id]      LEFT OUTER JOIN [Bin]   ON [Product].[prod_id] = [Bin].[prod_id]      ORDER BY [Product].[brd_id], [Product].[prod_brdId], [Size].[size_sort]  And my corresponding LINQ statement in .NET BinProds = ( from pd in applicationDbContext.Proddetails   join pc in applicationDbContext.Prodcolors on pd.PclId equals pc.PclId   join pr in applicationDbContext.Products on pc.ProdId equals pr.ProdId   join sz in applicationDbContext.Sizes on pd.PdtSize equals sz.SizeId   join bn in applicationDbContext.Bins on pr.ProdId equals bn.ProdId into ps                   from bn in ps.DefaultIfEmpty()   select new CoreBin   {     ... fields here   } ).Distinct().OrderBy(i=>i.BrdId).ThenBy(j=>j.ProdBrdId).ThenBy(k=>k.SizeSort).ToList();   So, both of these execute successfully in SQL Server Studio and .NET respectively.  However it's not giving me the exact result I'm looking for because it's missing one additional condition on the LEFT OUTER JOIN.  Below is the one change I made to my SQL statement which gives me exactly what I want in SQL Server Studio.  I just can't figure out how to adjust the LINQ to get the same result in my .NET project. LEFT OUTER JOIN [Bin] ON [Product].[prod_id] = [Bin].[prod_id] AND [Bin].[size_id] = [Size].[size_id]  I'm hoping there is a reasonable adjustment.  If you need my table outputs or db design, plz let me know.

I need to do a LINQ2DataSet query that does a join on more than one field (as  var result = from x in entity join y in entity2         on x.field1 = y.field1  and            x.field2 = y.field2   I have yet found a suitable solution (I can add the extra constraints to a where clause, but this is far from a suitable solution, or use  solution, but that assumes an equijoin).  Is it possible in LINQ to join on multiple fields in a single join?  EDIT  var result = from x in entity              join y in entity2              on new { x.field1, x.field2 } equals new { y.field1, y.field2 }   is the solution I referenced as assuming an equijoin above.  Further EDIT  To answer criticism that my original example was an equijoin, I do acknowledge that, My current requirement is for an equijoin and I have already employed the solution I referenced above.  I am, however, trying to understand what possibilities and best practices I have / should employ with LINQ. I am going to need to do a Date range query join with a table ID soon, and was just pre-empting that issue, It looks like I shall have to add the date range in the where clause.  Thanks, as always, for all suggestions and comments given