Allow moderators to see a summary of flags against a user's comments

Moderators have easy access to all posts from a user that have been flagged (and how those flags were resolved), and we can see all comments from a user (including deleted ones).  This feature request is to give us some insight into (helpful) flags against a user's comments.  If a user has a pattern of problematic posts we'll see that, but I've seen users who leave many rude or non-constructive comments.  These get flagged, the moderator who sees the flag cleans them up, and life goes on.  It can take a while for the pattern to emerge because each moderator sees only part of the problem -- and has to rely on his memory.  Meanwhile, the user continues the activity and it can become more entrenched.  It would be better to be able to spot that early so we can talk with the user about it -- a stitch in time and all that.  I would like be able to see that a user's comments had N offensive flags, M not-constructive flags, and so on for the other flag reasons.  I can think of two places where this could be put in the interface:   On the flags page, add a summary with the counts by flag type.  Again, we only care about flags that were marked helpful.  If a user also receives spurious flags, well that's not his fault so shrug.  (As pointed out in a comment, we'd also need some indication of timing -- are these recent flags or old?) On the "all comments" page, add information about flags to each comment.  This should be on the page itself, not behind "expander" widgets, so we can search the page easily.  Even better, just as we can filter for deleted and undeleted, add filters for flag types.   Option 1 gives us summary information only.  Option 2 gives us the details of which comments they were.  I don't know which would be easier to implement.  Either's fine with me.  We know that the information about the flag exists in the system, because (a) it shows up on the flagging user's "helpful flags" page and (b) it's in the timeline.  This is a request to expose that information in a way that allows moderators to more-easily notice users with a pattern of problematic comments.  Just giving us a total number of flagged comments doesn't address the need, because obsolete flags are usually not a sign of trouble.  Often, in fact, they're the sign of a helpful user -- the user commented with a question or suggestion, the post actually got fixed, and now the comment no longer applies.  .


I have a text file like so  foo bar baz 1   a   alpha 2   b   beta 3   c   gamma   I can use awk to print certain columns, like 1 and 3, with {print $1, $3}, but I want to specify the columns to print by specifying the header of the column instead, something like {print $foo, $baz}. This is useful so I don't have to open the file and count the columns manually to see which column is which, and I don't have to update the script if the column number or order changes. Can I do this with awk (or another shell tool)?


How do I make a 1x1x2 piston door that opens when I step on a plate and not the other way around?

In Minecraft I need to make a piston door that opens when a plate is stepped on, it is normally the other way around. Does anyone know how? A video would be helpful but not required.


I think my PC is being hacked. What should I do?

I'm afraid I'm being hacked: My Ubuntu is receiving inbound traffic while my PC is disconnected from Ethernet and WIFI, so my question is, how am I receiving inbound traffic? I even have a firewall that is turned on.  I'm studying to be a developer, so obviously I can't completely disconnect from the web.  How should I proceed?


How to set a command block to test for the time and change it?

I've been building up villages on my server, and I'd really like to not have to watch for zombie sieges. I'd like to set up a command block to detect when it is almost midnight, and then skip midnight. The old methods I've found on here aren't working as the /stats command has been removed.  Anyone know how I can do this? I'm running 1.15.2


Determine whether the series $\sum_{n=1}^{+\infty}\left(1+\frac{1}{n}\right)a_{n}$ is convergent or divergent

If $$\sum_{n=1}^{\infty}a_{n}$$divergent, determine whether the series $$\sum_{n=1}^{+\infty}\left(1+\dfrac{1}{n}\right)a_{n}$$ is convergent or divergent.  I know I have to use the ratio test.


I've never been a fan of Hungarian notation, I've always found it pretty useless unless you're doing some really low level programming, but in every C++ project I've worked on some kind of Hungarian notation policy was enforced, and with it the use of some 'not-really-Hungarian' prefixes as m_ for fields, s_ for statics, g_ for globals and so on.  Soon I realized how much useless it was in C# and gradually started to drop all of my old habits... but the 'm_' thing. I still use the m_ prefix on private fields because I really find it very useful to being able to distinguish between parameters, locals and fields.  The  says I shouldn't, but it does not say why (the way e.g. Google's conventions generally tend to rationalize their prescriptions).  Are there reasons why I shouldn't or is it only a matter of style. If it is the latter, are prefixes generally considered a bad style and can I expect negative reactions from other people working on the codebase?


I installed Ubuntu 12.04 on my laptop, but now my wifi doesn't work. I installed the additional driver which was just the software modem.   I don't know what else to do about it except for installing the updates, but any time I try, it gets stuck configuring bcmwl-kernel source.   This is my first experience with Ubuntu and I haven't been working with computers for very long, so please speak in simple terms.


How can we detect seasonality in a time series without looking at its plot?

I am wondering if is there a way that we can mathematically or statistically identify seasonality in time series without the need to look at its plot?


Need help with RHS of Induction Problem about $1^{3} + 2^{3} + ... + n^{3}$ = $(1 + 2 + ... + n)^{2}$

Prove $1^{3} + 2^{3} + ... + n^{3}$ = $(1 + 2 + ... + n)^{2}$ for all positive integers n.  I've tried to work with this problem using mathematical induction. However, I really don't understand how to manipulate the right side of the equation. Any help would be greatly appreciated.  Thank you in advance.


Is there a name for an algebraic structure like this?

I'm self studying abstract algebra. I see that in rings there's no requirement for a multiplicative inverse.  Is there something similar except with no requirement for an additive inverse. For example, all the non-negative rational numbers. Every number other than 0 has a multiplicative inverse, but no additive inverses. We have both the multiplicative and additive identities. Multiplication is still associative over addition.  Is there a name for such an algebraic structure, and has it been studied the way rings have?


Is Canadian Visa required if just in Toronto changing flights?

I am flying from Pakistan to the US, and will be changing flights in Toronto.  I will not be leaving the airport and my ground time in Canada is less then 5 hours.  I have a visit visa for the US.  Do I need a transit visa or some kind of visa for Canada?


C language: How exactly is the size of an array calculated in C

Memory addresses specify how many bytes of data they point to in memory, so it seems that the size of any variable is determined by looking at the memory address and seeing how much the variable occupies in memory. So how is the size of an array determined??? - because an array is a pointer to only the first item in the array by default:  int main() {     int a[] = {1,2,3,4,5};     // both show same memory address     printf("%p\n", a);     printf("%p\n", &a[0]);     // somehow the entire size of a is calculated     printf("%lu\n", sizeof(a)); // 20 (all elements)     return 0; }


Simple demonstration for $\lim_{n\to\infty}(\sqrt[n+1]{(n+1)!}-\sqrt[n]{n!}) = \frac{1}{e}$

What is the simple demonstration with elementary means for Lalescu Sequence: $$\lim_{n\to\infty}(\sqrt[n+1]{(n+1)!}-\sqrt[n]{n!}) = \frac{1}{e}?$$  (Traian Lalescu-romanian mathematician (1882-1929))


Questions about insects eating flour and living in the cracks of a wooden cutting boards

I have a large wooden cutting board which is used in my kitchen mainly for preparing egg pasta. The wood type is Populus (poplar or aspen or cottonwood).  The main ingredients used with the cutting board are: flour (mainly soft wheat flour), hens' eggs, white sugar, butter, and baking powder.  After the food preparation, the cutting board is cleaned by scraping away the ingredients remains.  The board has some cracks and some small unknown insects are living inside the cracks.   The board has also a lot of holes due to woodboring beetles but I think the woodworms operated long time ago and they no longer live in the cutting board.  The unknown insect has an approximate length of 1 mm (along the direction of their movements) and a width of 0.3 mm. The unknown insects do not have wings, they just walk. I am not able to see how many pairs of legs they have.  The color of the insect is pale brown.  The cutting board was free from these unknown insects some months ago but then they appeared.  My questions:   What insects are they? Are these insects poisonous to humans? How can I get rid of them?   Update  The unknown insects could be Acarus siro, I will try to get a picture of the insects.  Update 2  Here is a picture. The bottom part of the image is a one Euro coin, the top part of the image is a caliper (each bright area is one mm tick).   Some more pictures:


TiKZ Node positioning left of A but below B

Assume I have the following snippet/screenshot. How can I get Desc2 on the same line as Desc1. So Desc2 should be vertically placed below T2 but horizontally at the same level as Desc1 so that the descriptions are laid out on the same line.  More in general: how to position a node horizontally relatively from node X, but vertically from node Y?  Preferable a solution without calc or matrix (free node placement)   So I am looking something like:   \node[below of=t2 left of d1] {Desc2};   What is the easiest way to do this?  MWE:      \documentclass[tikz]{standalone}     \usepackage{tikz}     \usetikzlibrary{positioning}     \begin{document}         \begin{tikzpicture}[align=center,node distance=2cm]          \node[style={circle}] (t1) {T1} -- (t1)                    node[above left of=t1,style={circle}] (t2) {T2};           \path[draw,->] (t1) -- (t2);                   \node[below of=t1]  (d1) {Desc1};             \node[below of=t2] {Desc2};           \end{tikzpicture}     \end{document}


In what order does the shell execute commands and stream redirection?

I was trying to redirect both stdout and stderr to a file today, and I came across this:  <command> > file.txt 2>&1   This apparently redirects stderr to stdout first, and then the resulting stdout is redirected to file.txt.  However, why isn't the order <command> 2>&1 > file.txt? One would naturally read this as (assuming execution from left to right) the command being executed first, the stderr being redirected to stdout and then, the resulting stdout being written to file.txt. But the above only redirects stderr to the screen.  How does the shell interpret both the commands?


Xubuntu 18.04 Persistent Live USB: Will persistence be carried upon full installation to a machine?

I've created an Xubuntu 18.04 persistent live USB stick and installed several softwares for web development, such as XAMPP, Sublime Text 3, Google Chrome, etc.. I did some configurations as well in the ~/.bashrc file.  I am wondering if these installation and configuration in my persistent live USB stick be carried over in a full installation in to a new machine using it.


Prove $\lim_{x\to\infty}\frac{f(x)}{x}=0$ if $f$ is continuous and $\lim_{x\to\infty}f(x+1)-f(x)=0$

This is Problem 22-17 in Spivak's Calculus (3rd edition). It says to use the previous problem, which is if $\lim_{n\to\infty}a_n=l$, then $$\lim_{n\to\infty}\frac{\sum_{i=1}^n a_n}{n}=l.$$ I think I'm supposed to let $a_n=f(n)-f(n-1)$ and then $\sum_{i=1}^n a_n=f(n)-f(0)$, so $$\frac{\sum_{i=1}^n a_n}{n}=\frac{f(n)-f(0)}{n}$$ which has the same limiting behavior as $\frac{f(n)}{n}$. But I can't figure out how to use the continuity of $f$, as something like a rescaled version of $\tan$ is periodic and so $f(n+1)-f(n)=0$, but $\lim_{x\to\infty}\frac{\tan(x)}{x}\neq 0$.


My fluid simulation baked and showed up, but when I rendered it it shoed no simulation. The rendered viewport even shows the fluid! The bottom part of the screen shows the rendered viewport, the top screen shows the images after rendered


How can I simply prove that the pearson correlation coefficient is between -1 and 1?

For building a recommendation system, I also use the Pearson correlation coefficient. This is the definition:  $r(x, y)=\frac{\sum_{i=1}^n (x_i-\bar{x})(y_i-\bar{y})}{\sqrt{\sum_{i=1}^n (x_i-\bar{x})^2 \cdot \sum_{i=1}^n (y_i-\bar{y})^2}}$  $x$ and $y$ are part of $\mathbb{R}$.  Now for coding, it is important to take care of all potential outcomes. For example, if the denominator is zero, you will have to filter that or throw an exception.  I came up with some arguments, one of them being that if all values of $x_i$ and/or $y_i$ were equal to the average of $x$ and/or $y$, then the denominator would be zero.  But how can I prove that the coefficient is either undefined (zero denominator) or in between -1 and 1? What is the best approach?


Newbie question - CD cmd not working - what am I doing wrong?

I am in my home folder, I can list the folders their and can see 'Documents' folder. But when I issue CD command - it says no such folder or directory!


When I try to install ubuntu it comes up with a black screen that reads:[Firmware Bug]: TSC_DEADLINE disabled due to Errata; please update microcode to version: 0x52 (or later). Then the screen freezes and I cannot type anything like other guides say. Does anyone know whats wrong?


SFTP, SSH Couldn't read packet: Connection reset by peer

My sftp -v to host returns,  Connecting to xxx.xx.xx.xx... OpenSSH_3.9p1, OpenSSL 0.9.7a Feb 19 2003 debug1: Reading configuration data /etc/ssh/ssh_config debug1: Applying options for * debug1: Connecting to xxx.xx.xx.xx [xxx.xx.xx.xx] port 22. debug1: Connection established. debug1: permanently_set_uid: 0/0 debug1: identity file /root/.ssh/id_rsa type 1 debug1: identity file /root/.ssh/id_dsa type 2 debug1: Remote protocol version 2.0, remote software version OpenSSH_5.3 debug1: match: OpenSSH_5.3 pat OpenSSH* debug1: Enabling compatibility mode for protocol 2.0 debug1: Local version string SSH-2.0-OpenSSH_3.9p1 debug1: SSH2_MSG_KEXINIT sent debug1: SSH2_MSG_KEXINIT received debug1: kex: server->client aes128-cbc hmac-md5 none debug1: kex: client->server aes128-cbc hmac-md5 none debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP debug1: SSH2_MSG_KEX_DH_GEX_INIT sent debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY debug1: Host 'xxx.xx.xx.xx' is known and matches the RSA host key. debug1: Found key in /root/.ssh/known_hosts:63 debug1: ssh_rsa_verify: signature correct debug1: SSH2_MSG_NEWKEYS sent debug1: expecting SSH2_MSG_NEWKEYS debug1: SSH2_MSG_NEWKEYS received debug1: SSH2_MSG_SERVICE_REQUEST sent debug1: SSH2_MSG_SERVICE_ACCEPT received debug1: Authentications that can continue: publickey,password,keyboard-interactive debug1: Next authentication method: publickey debug1: Offering public key: /root/.ssh/id_rsa debug1: Authentications that can continue: publickey,password,keyboard-interactive debug1: Offering public key: /root/.ssh/id_dsa debug1: Authentications that can continue: publickey,password,keyboard-interactive debug1: Next authentication method: keyboard-interactive debug1: Authentications that can continue: publickey,password,keyboard-interactive debug1: Next authentication method: password user@xxx.xx.xx.xx's password: debug1: Authentication succeeded (password). debug1: channel 0: new [client-session] debug1: Entering interactive session. debug1: channel 0: free: client-session, nchannels 1 debug1: fd 0 clearing O_NONBLOCK Read from remote host xxx.xx.xx.xx: Connection reset by peer debug1: Transferred: stdin 0, stdout 0, stderr 61 bytes in 0.0 seconds debug1: Bytes per second: stdin 0.0, stdout 0.0, stderr 60334.5 debug1: Exit status -1   This only occurs with this user. I created a test user which works and other existing users don't have and issue (well no reported issues by users).


Access both web.config and app.config from a single class

I need to read data from both app.config and web.config. My class will have read/write/update methods wrapped in a dll which will be used both by an application (exe) and by a web application. I need to make sure that i access the caller's default configuration file.  For app.config,   Configuration config = ConfigurationManager     .OpenExeConfiguration(ConfigurationUserLevel.None);   works fine.  What would be the equivalent code for web.config?  (P.S.: I read that     Configuration config = WebConfigurationManager     .OpenWebConfiguration(HttpContext.Current.Request.ApplicationPath)   works and some say that   Configuration config = WebConfigurationManager.OpenWebConfiguration("~");   would work. Which of these actually works and is more general? Or is there any other better alternative?


I have to  prove that $\sqrt 3$ is irrational.  let us assume that $\sqrt 3$ is rational. This means for some distinct integers $p$ and $q$ having no common factor other than 1,   $$\frac{p}{q} = \sqrt3$$  $$\Rightarrow \frac{p^2}{q^2} = 3$$  $$\Rightarrow p^2 = 3 q^2$$  This means that 3 divides $p^2$. This means that 3 divides $p$ (because every factor must appear twice for the square to exist). So we have, $p = 3 r$ for some integer $r$. Extending the argument to $q$, we discover that they have a common factor of 3, which is a contradiction.  Is this proof correct?


Per-site Meta post didn't populate Moderator Inbox

Per  I'm posting this issue.  I'm a moderator over on Sci-fi & Fantasy.SE.  My moderator inbox missed :    The Meta Question in question should show up after the moderator message and before the new meta question, as it was posted on Jan 2 (it's currently Jan 6, so '2 days ago' is Jan 4).


I have a very little knowledge about the 'Snap packaging format'. What I know is that 'Snap' is an alternative packaging format like .deb.   What I don't know is    Why did Canonical chose it? What are the main advantages of 'Snap' over .deb? Will .deb be abandoned, or is it already abandoned?


How does the aperture affect the focus area? Here are some examples:  With an 35mm(50mm)/f1.8 prime lens   What f-value will bring a group of people standing in five rows into focus? What f-value will bring the entire face and body into focus, when shooting close-ups or portraits? How do you focus on two peoples standing far from each other? How do you focus a group of players playing in ground?   Do these all differ for various physical distances between the subject and camera?


For a project I am working on, I need some kind of way for a micro-controller (preferably Arduino, since I have background knowledge) to identify a certain symbol on a piece of paper (e.g. recognising an ampersand drawing), and then run some code depending on what it sees. The more symbols it could recognise, the better.    I understand that for identifying pictures in almost any program, you need a database to refer to. I assume this wouldn't be too difficult, but some tips on managing a database would be appreciated.    If there aren't any simple Arduino programs that exist, I could work with a pre-existing IC built for this purpose (I don't know if that would make sense, but just throwing ideas around). A link to a datasheet would also be appreciated.


Unable to locate element using string Actualtext xpath

package Practice_KingAllProg;  import java.util.concurrent.TimeUnit;  import org.openqa.selenium.By; import org.openqa.selenium.WebDriver; import org.openqa.selenium.chrome.ChromeDriver;   public class Crmpro_Iframe_King2410 {      public static void main(String[] args) {         // TODO Auto-generated method stub          try {             System.setProperty("webdriver.chrome.driver",                     "C:\\Users\\Sahil\\selelniumPratice\\Webdriver_PracticeKing\\src\\test\\resources\\BroWser_PracticeKing\\chromedriver.exe");             WebDriver driver = new ChromeDriver();             driver.get("https://www.crmpro.com/index.html");             Thread.sleep(5000);             driver.manage().timeouts().pageLoadTimeout(30, TimeUnit.SECONDS);             driver.manage().timeouts().implicitlyWait(30, TimeUnit.SECONDS);             driver.manage().window().maximize();             driver.findElement(By.name("username")).sendKeys("sa12");             driver.findElement(By.name("password")).sendKeys("vi123");             driver.findElement(By.xpath("//*[@id=\'loginForm\']/div/div/input")).click();             driver.switchTo().frame("leftpanel");             Thread.sleep(5000);             driver.switchTo().defaultContent();         String Actualtext = driver.findElement(By.xpath("//html//body//table[1]//tbody//tr[1]//td//table//tbody//tr//td[1]")).getText();         //html/body/table[1]/tbody/tr[1]/td/table/tbody/tr/td[1]         System.out.println(Actualtext);         String Exceptedtext="sanjay spear";         if(Actualtext.equalsIgnoreCase(Exceptedtext))         {             System.out.println("Pass");         }else         {             System.out.println("Fail");         }              driver.quit();         } catch (InterruptedException e) {             // TODO Auto-generated catch block             e.printStackTrace();         }      }  }


Where can I see the date I created my Gmail account?

Well, it's a long time I'm using my Gmail account. Today, I had a talk with my friends about the date we created our Gmail accounts and we all had some guesses about it. Is there any option in Gmail info/settings where I can see the date I created my account?


Position of line numbers using algorithm2e and fontenc

I want to present an algorithm with the package algorithm2e. It mostly works fine, only the position of the line numbers are wrong. The numbers are printed within the margin of the page.   I figured out, that it is an interaction with the fontenc package. But I need fontenc and I am looking for a solution. In the pictures you can the the problem and how ist should be. Is there a solution?  You find the code below as well as pictures. Because the document's language is German, I need all included packages...  \documentclass[a4paper,parskip=half]{scrbook} \usepackage[ngerman]{babel}          \usepackage[utf8x]{inputenc}          \usepackage[T1]{fontenc}             \usepackage[vlined,ruled,linesnumbered]{algorithm2e}   \begin{document} I am the text and I decide the width of the page. Nothing should be wider than me, especially not the line numbers.       \begin{algorithm}      \SetAlgoLined      \KwIn{this text}      \KwOut{how to write algorithm with \LaTeX2e }       initialization\;      \While{not at end of this document}{        read current section\;        \eIf{understand}{          go to next section\;          current section becomes this one\;          }{          go back to the beginning of current section\;          }        }      \caption{How to write algorithm}    \end{algorithm} \end{document}   This is generated with the code above    This is generated with the code above, but with deleted fontenc package


Will windows applications run on ubuntu?

If I switch to ubuntu from windows will my programs from windows still work on ubuntu? or will I have to download the ubuntu counterpart of the program?


Can a shadow sorcerer see in darkness created by another shadow sorcerer?

I have a party with 2 Shadow Sorcerers. If one of them casts darkness with sorcery points, is there a way - RAI or RAW it doesn't matter- for the other sorcerer to see through it?  It seems stupid that a shadow sorcerer can't see through a spell cast with his own capacity.


Clarification on assassinations in the film Looper

When the main character's money ran out when he was in China, he did freelance assassination jobs to cover his expenses; in the near future where, "disposing of bodies" is  near impossible to be kept secretly. What would be the difference between time-travel assassinations and daylight assassinations if syndicates and freelance assassins still kill openly in the future? Like when they killed main character's wife? I don't see the purpose of sending people to the past if they still do open killings in the future.


ASUS TP200 Touchpad gestures doesn't work (16.04)

eronis@Asus:~$ xinput list ⎡ Virtual core pointer                      id=2    [master pointer  (3)] ⎜   ↳ Virtual core XTEST pointer                id=4    [slave  pointer  (2)] ⎜   ↳ FTE1000:00 0B05:0101                      id=10   [slave  pointer  (2)] ⎜   ↳ SIS0457:00 0457:1136                      id=11   [slave  pointer  (2)] ⎣ Virtual core keyboard                     id=3    [master keyboard (2)]     ↳ Virtual core XTEST keyboard               id=5    [slave  keyboard (3)]     ↳ Power Button                              id=6    [slave  keyboard (3)]     ↳ Video Bus                                 id=7    [slave  keyboard (3)]     ↳ Sleep Button                              id=8    [slave  keyboard (3)]     ↳ USB2.0 VGA UVC WebCam                     id=9    [slave  keyboard (3)]     ↳ Asus WMI hotkeys                          id=12   [slave  keyboard (3)]     ↳ AT Translated Set 2 keyboard              id=13   [slave  keyboard (3)]      Device 'Virtual core pointer':     Device Enabled (139):   1     Coordinate Transformation Matrix (141): 1.000000, 0.000000, 0.000000, 0.000000, 1.000000, 0.000000, 0.000000, 0.000000, 1.000000   I can't scroll or do any multitouch gesture on my touchpad. How can I solve this ? Thanks for help already :)


My app resets my integers when switching from horizontal to vertical

So this is my first app on android and it's working great. However, when I tilt the screen to its horizontal view then my integers get reset to zero. If I start horizontally then switch it to vertical, it resets the integers to zero too. How can I get it to not reset and just switch?


What does Density mean on Y-axis in qplot()?

I'm a beginner at R. I was trying out some code for implementing a basic qplot() on the inbuilt 'mtcars' dataset in R.  #Kernel Density Plot for mpg (miles per gallon) #grouped by number of gears (indicated by color) qplot(mpg, data=mtcars, geom="density", fill=gear, alpha=I(0.5),       main="Distribution of Gas Milage", xlab="Miles Per Gallon",        ylab="Density")   and the graph is as follows:   I'm unable to understand what those Density decimal values mean on the Y-axis. What do they say about the Miles Per Gallon distribution(X-axis)???


Run PyQGIS from outside QGIS on MacOS HighSierra

I know this question has already been asked multiple times but I just can't figure it out. I am working on MacOS HighSierra 10.13.6 and QGIS 3.16. I also have Python 3.6 and 3.9 installed. Python 3.6.7 is accessed via python3 in the terminal. I try to run QGIS algorithms within my python script and am therefore lookin for sth like this: import os import sys sys.path.append('/Applications/QGIS.app/Contents/Resources/python/') sys.path.append('/Applications/QGIS.app/Contents/Resources/python/plugins') from qgis.core import *  But I always get this error: ImportError: dlopen(/Applications/QGIS.app/Contents/Resources/python/qgis/_core.so, 2): Library not loaded: @rpath/qgis_core.framework/Versions/3.16/qgis_core   Referenced from: /Applications/QGIS.app/Contents/Resources/python/qgis/_core.so   Reason: image not found


I'm trying to understand this proof and I can follow it up the the second last paragraph where it states what happens if n is odd/even. I don't understand why there is just one conjugacy class when n is odd and two when n is even.    Help much appreciated, thanks!


Home shortcut key to my designated webpage?

I was wondering if there is an android shortcut to make things more efficient.


Showing bound for operator norm on $\mathcal{L}(L^p)$

Let $f \in L^p(0,\infty)$, and consider \begin{equation}F_f(x) = \frac{1}{x}  \int_0^x f(y) dy \end{equation} where $F:L^p(0,\infty) \rightarrow L^p(0,\infty)$, show that  \begin{equation} \|F\| \leq \frac{p}{p-1} \end{equation}  I can come up with the denominator if I majorate the integral on $F$ by $\|f\|_p$ but i get stuck with $\int_0^\infty x^{-p}$ and this blows up.   I also tried using holder on $\int |f(y)|dy$ but couldn't get anywhere.   Any hints on how to majorate this norm?


Why do all the commands in terminal not print newline?

Not sure what happened to make my terminal mess: ➜ ls Dockerfile               README.md                docker-compose.yml       node_modules             tini                                                                                Dockerfile.china         bin                      e2e-test.Dockerfile      package.json             yarn-error.log                                                                                Jenkinsfile              create_git_properties.sh git.properties.json      packages                 yarn.lock                                                          Jenkinsfile_China        deploy                   lcov.info                rest-client         Makefile                 deploy-only-cn           lerna.json               sonar-project.properties                                                                                %  How do I recover without close and reopen the terminal? Notice the extra % means the previous command didn't print the newline as ending, instead it prints some others(). The expected output should be like the following: ➜ ls Dockerfile               README.md                docker-compose.yml       node_modules             tini Dockerfile.china         bin                      e2e-test.Dockerfile      package.json             yarn-error.log Jenkinsfile              create_git_properties.sh git.properties.json      packages                 yarn.lock Jenkinsfile_China        deploy                   lcov.info                rest-client Makefile                 deploy-only-cn           lerna.json               sonar-project.properties   Thanks in advance!


How to select cog for emergency single speed conversion with a broken derailleur

I broke the rear derailleur on my surly karate monkey recently.  I had the bike setup 2x9. I decided to try and get home by converting to single speed via trail side repair (made easier by the horizontal dropouts on the bike).   I put the chain on the big chainring in the front, figuring the front derailleur would hold it in place. I pulled the chain out of the derailleur, shortened the chain so it would not be routed through the derailleur, and I tried to find the straightest line in the rear, and selected the 20t cog to place the chain on, this was the 4th cog in from the end of the cassette.   I pulled the rear wheel backwards to tension the chain as much as possible. I had already been using a chain tensioner (surly tuggnut) to keep it stationary, so I screwed that down to keep the rear wheel from slipping under pedaling.   However, after a short time, the chain started to upshift on the cassette. It went up a cog and jammed, shifting the non-driveside forward, pushing my tire in to my chainstays. this was difficult to fix, because I had to remove the tuggnut and undo my very tight quick release.  What's the best practice for positioning the chain in the rear to avoid auto shifting and jamming like I'm experiencing?


How to make a div fill remaining vertical space?

I have two main sections in the page 1) Topbar 2) Container. The topbar has a fixed height of 50px and the container should have the remaining height.  I tried giving the container height as 100% but its not working correctly as it is making the webpage take 100% + 50px. Hence I am getting a vertical scrollbar which I am trying to avoid.   Here is a fiddle to demonstrate my issue. Please use the full screen view     How can I solve this issue ?    Update 1  I tried the solution posted in posted here  but for some reason its not working for me. Please see this fiddle .


How were the software such as Ubuntu software center created?

What programming languages were used to create software like Ubuntu Software Center or System Monitor?  How was the GUI created? The reason I am interested is that I need to create a desktop application on Ubuntu.


How to reverse order a list? (Python 3.x)

How to reverse order the list containing strings where def view(self), because with reversed() I get an error that it can't be done with strings. Any help?   class Stack():      def __init__(self):         self.stack = []      def view(self):         for x in reversed(self.stack):             print(self.stack[x])      def push(self):         item = input("Please enter the item you wish to add to the stack: ")         self.stack.append(item)      def pop(self):         item = self.stack.pop(-1)         print("You just removed item: {0}".format(item))  stack = Stack()


Story about miniature aliens who live in cereal boxes

When I was younger (in the 90s) I read some paperback books about aliens who, if I remember correctly, lived in cereal boxes. They had enemies whose main weakness was a craving for pepper flakes, but who would die if they ate too much.


Do you use adverbs to modify these v-ing words especially when they are the objects of the verbs?  Example:      I regret swimming hurriedly   **I regret hurried swimming.   And what about these two sentences:      I regret stamp-collecting   I regret collecting stamps      I regret unnecessary bomb-defusing.   I regret bomb-defusing unnecessarily?   Besides, when using these words, it still retains the verbal characteristics right? Like:     The house needs a careful cleaning   has the same meaning as:      The house needs carefully cleaning   The house needs to be cleaned carefully (SOMETHING like passive voice)


I am quite new to TeX. I want that each line in the following equation be centered, but I cannot find how to do it.  \documentclass{article} \usepackage{amsmath} \begin{document} \begin{equation} \begin{split} a & = \frac{M_{20}}{M_{00}} - x^{2}_{c}, \;\;\; b = 2(\frac{M_{11}}{M_{00}} - x_{c}y_{c}), \;\;\; c = \frac{M_{02}}{M_{00}} - y^{2}_{c}, \\ &\quad x_{c} = \frac{M_{10}}{M_{00}}, \;\;\; y_{c} = \frac{M_{01}}{M_{00}}, \\ &\quad M_{ij} = \displaystyle\sum\limits_{x} \displaystyle\sum\limits_{y} x^i y^j I(x,y) \end{split} \end{equation} \end{document}   Also, it would be awesome if I could write "and" after the first line ;)  Thanks in advance


Is there any way to define a new value that is a counter + a constant?  e.g.  \foreach\k in {0,1,...,7} {    \def\m    % ???? I want to make m=k+4    \draw[->] (box\k) -- (box\m); }


Electric potential is related to Electric Field by negative integral of Field with distance.If charges move away from the positive terminal (Assuming conventional flow) why is there no drop in electric potential even though the charges are moving in the direction of electric field?  Some of the answers I read for the similar question said that the electrons in wires rearrange themselves in a way to make the electric field uniform in the wire.However,this doesn’t explain the absence of potential drop in the wires (due to electric field) since the field is still there.


In that folder are stored the news files: they can be created by the system administrator to write some informations for the users, as suggested in  link.  I tried as a normal user to add a file in /var/lib/sysnews, but nor this command  echo "Hello world" > /var/lib/sysnews   neither this command  sudo echo "Hello world" > /var/lib/sysnews   worked (it gives permission denied error).  The folder is owned by root user and by the staff group. My normal user was already in the sudo group; I added the staff group for my user, but with no results.  I can add news only by creating a file in one of my folders and then typing  sudo mv myfile /var/lib/sysnews   but it is bothering.  Is there a simpler way to add some news file to that folder without being root?


Subgroup generated by $2$ and $7$ in $(\mathbb Z,+)$

In group $(\mathbb Z,+)$ , the subgroup generated by $2$ and $7$ is   $\mathbb Z$ $5\mathbb Z$ $9\mathbb Z$ $14\mathbb Z$   In general what's the result for any $n$, $m$ instead of $2$ and $7$.   I think it should be $\gcd(n, m)$. Is that correct?


I've been trying to fill those lidar scan lines in my dem with no avail. Is there any way to interpolate those "gaps" to get a clean dem? I used las2dem to create the dem from .laz file


Can Eldritch Knights Use Spell Foci and if so what things do they use as them?


How does the trace acts over one of the two entangled qubits?

If $|\psi\rangle$ is entangled, i.e, is in the subspace spanned by the states $|00\rangle, |01\rangle, |10\rangle, |11\rangle$ how does the partial trace operates on the density operator $|\psi\rangle\langle\psi|$, if I only want it to operate on the first qubit.  $$ Tr_{1}(|\psi\rangle\langle\psi|) $$


Complex number isomorphic to certain $2\times 2$ matrices?

I have been trying to prove this, but I am having trouble understanding how to prove the following mapping I found is injective and surjective. Just as a side note, I am trying to show the complex ring is isomorphic to special $2\times2$ matrices in regard to matrix multiplication and addition. Showing these hold is simple enough.  $$\phi:a+bi \rightarrow \begin{pmatrix} a & -b \\ b & a \end{pmatrix}$$  This is what I have so far:  Injective: I am also confused over the fact that there are two operations, and in turn two neutral elements (1 and 0). Showing that the kernel is trivial is usually the way I go about proving whether a mapping is injective, but I just can't grasp this.  $$ \phi(z_1) = \phi(z_2) \implies \phi(z_1)\phi(z_2)^{-1} = I = \phi(z_1)\phi(z_2^{-1}) = \phi(z_2)\phi(z_2^{-1}).$$  So if we can just show that the kernel of $\phi$ is trivial, then it also shows that $z_1 = z_2$. The only complex number that maps to the identity matrix is one where $a = 1$ and $b = 0$, $a + bi = 1 + 0i = 1$.  Using a similar argument for addition we can just say that the only complex number $z$ such that $\phi(z) = 0\text{-matrix}$, is one where $a=0$ and $b=0$, $a+bi=0+0i=0$.   Surjective:  I forgot to add this before I posted, but I honestly don't really understand how to prove this because it just seems so obvious. All possible $2\times2$ matrices of that form have a complex representation because the complex number can always be identified by its real parts and since the elements of the $2\times2$ matrix are real then the mapping is obviously onto.  I have always had trouble understanding when I can say that I have "rigorously" proved something, so any help would be appreciated!


What's a good word or idiom for the action (or the person) of creating unnecessary work steps when the task at hand can be accomplished much faster?

For example, it would take me 3 min to email a supplier about an update on a recent purchase, or I could start a new task board, set up an account for my PA, and assign him this task, which would take 15 minutes (so 5 times the amount of time) - what's the word for that type of pen pushing overkill?


Is there any way to set factional scaling in ubuntu 20.04 to 110% instead of 125% or 150%? Because 100% is too small and 125% is too large for me. Thanks.


How do I use shell commands in Code::blocks c++?

I have a project in which I have to use the linux shell commands "wc" and "date" in a c++ program. I'm using the code::blocks IDE to make my .cpp file but I don't know how to use those commands within the compiler. Any tips?


Find all functions $f:\mathbb{R} \to \mathbb{R}$ such that $f(x^2 + y + f(y)) = 2y + (f(x))^2$

Find all functions $f:\mathbb{R} \to \mathbb{R}$ such that $$f(x^2 + y + f(y)) = 2y + (f(x))^2$$  I tried something like  but that inner $f(y)$ makes things worse to my opinion. Any help is appreciated.


Find every possible function that fits the criteria

** Find every possible $f:\Bbb{Q}\rightarrow \Bbb{Q}$ such that $f(x) + f(t) = f(y) + f(z) $ where $x < y < z < t$ and x, y, z, t make an arithmetic progression  ** I couldn’t come up with much: f = const obviously works :) I also noticed that x & t and y & z have the same arithmetic mean.


How can I construct a universal transformation using Clifford+T gates?

How can I construct, using Pauli, Hadamard and $T$ gate, a universal transformation $U$ such that $U|0\rangle$ has a less than $\frac{\pi}{4}$ complementary angle with $|0\rangle$?


I need to export color orthophoto map to gray scale geotiff file using free tools (like qgis) any idea?  I tried qgis preview but this does not produce new geotiff file


Error message "A potentially dangerous Request.Form value"

I have added TinyMCE editor to add description in HTML format but when I write something in HTML and click Add Product It gives me this error:     A potentially dangerous Request.Form value was detected from the client (Description="   I've tried:   AllowHtml  <= not working [HttpPost, ValidateInput(true, Exclude = "Description")] and get this error       System.Web.Mvc.ValidateInputAttribute' does not contain a definition for Exclude    <httpRuntime requestValidationMode="2.0"> in web.config and getting this error      HTTP Error 500.19 - Internal Server Error The requested page cannot be accessed because the related configuration data for the page is invalid.   Product.cs  public partial class Product {       public int productID {get; set;}       [Required]      public int Name {get; set;}       [AllowHtml]      public string Description {get; set;}       public string ImagePath {get;set} }   Add Product View  @using (Html.BeginForm("AddProduct", "Store", FormMethod.Post, new { enctype = "multipart/form-data",   @class = "form-horizontal", role = "form" })) { @Html.AntiForgeryToken()
Create a new product.

 @Html.ValidationSummary(true) @ViewBag.SizeMsg
     @Html.LabelFor(m => m.Name, new { @class = "col-md-2 control-label"})
         @Html.TextBoxFor(m => m.Name, new { @class = "form-control" })         @Html.ValidationMessageFor(m=>m.Name)

     @Html.LabelFor(m => m.Description, new { @class = "col-md-2 control-label" })
         @Html.TextAreaFor(m => m.Description, new { @class = "form-control" })

     @Html.LabelFor(m => m.ImagePath, new { @class = "col-md-2 control-label" })
         <input type="file" name="file" id="file" style="width: 100%;" />

         <input type="submit" class="btn btn-default" value="Add Product" />

 }   Controller  [HttpPost] public ActionResult AddProduct(HttpPostedFileBase file) {    if (file != null)    {       var allowedExtensions = new[] { ".jpg", ".png", ".jpeg", ".gif", ".JPG", ".PNG", ".JPEG" };       if (allowedExtensions.Contains(extension))       {         string ImagePath = System.IO.Path.GetFileName(file.FileName);         string physicalPath = Server.MapPath("~/ProductImages/" + ImagePath);         file.SaveAs(physicalPath);          Product newRecord = new Product();         newRecord.Name = Request.Form["Name"];         newRecord.Description = Request.Form["Description"];         newRecord.ImagePath = ImagePath;         db.Products.Add(newRecord);         db.SaveChanges();         return RedirectToAction("Index", "Home");       }       else       {         ViewBag.SizeMsg = "File not supported.";         return View();        }    }    return View();  }


Constructing example showing $\mathbb{E}(X^{-1})=(\mathbb{E}(X))^{-1}$

How to construct an example of a probability distribution for which $\mathbb{E}\left(\frac{1}{X}\right)=\frac{1}{\mathbb{E}(X)}$ holds, assuming $\mathbb{P}(X\ne0)=1$?    The inequality which follows from Jensen's inequality for a positive-valued RV $X$ is like $\mathbb{E}\left(\frac{1}{X}\right)\ge\frac{1}{\mathbb{E}(X)}$ (the reverse inequality if $X<0$). This is because the mapping $x\mapsto\frac{1}{x}$ is convex for $x>0$ and concave for $x<0$. Following the equality condition in Jensen's inequality, I guess the distribution has to be degenerate for the required equality to hold. A trivial case where the equality holds is of course if $X=1$ a.e. Here is an example I found in a problem book: Consider a discrete random variable $X$ such that $\mathbb{P}(X=-1)=\frac{1}{9}, \mathbb{P}(X=\frac{1}{2})=\mathbb{P}(X=2)=\frac{4}{9}$. It is then easily verified that $\mathbb{E}\left(\frac{1}{X}\right)=\frac{1}{\mathbb{E}(X)}=1$.   This example shows that $X$ need not be positive (or negative) a.e. for the equality in the title to hold. The distribution here is not degenerate either.  How do I construct an example, possibly like the one I found in the book? Is there any motivation?


How to send email to multiple recipients using drupal_mail?

I am using drupal_mail to send email,  $to = 'email@email.com'; drupal_mail('$module_name', $key, $to, language_default(), $params = array('username' => 'Tanvir'), $from = NULL, $send = TRUE);   I want to send email to multiple email addresses at once. Should I be doing this?  $to  = array('one@email.com', 'two@email.com', 'three@email.com',); drupal_mail('$module_name', $key, $to, language_default(), $params = array('username' => 'Tanvir'), $from = NULL, $send = TRUE);


difference between $wp_the_query and $wp_query? & getting the values properly

i have seen $wp_query and $wp_the_query in many plugins and themes. for me these two are just same thing with no difference. i am not looking to either use or get the values from $GLOBALS.  what is the actual difference between these two objects and when to use them?  What is the proper action /filter hook for getting and reading values from $wp_query and $wp_the_query.


How can I set my system to suspend when inactive to a longer amount of time

I run Mythtv on some Ubuntu 11.10 based machines.  In the power settings, I can choose from a list of time periods from 5 minutes up to 1 hour for the the machine to suspend when inactive.  I would like to set the suspend to occur at a longer interval, like 2 hours or 4.  Previously with Gnome, I would think that I could go into the gconf editor and find the key there, I am not sure with Unity where to override a setting like this.  Any suggestions?


I'm unable to pick up the Gauldur Amulet fragment in Geirmund's Hall

I'm unable to retrieve the amulet fragment of the Gauldur Amulet in Geirmund's Hall. This most likely is the result of me clearing the dungeon without the quest a couple of hours ago and perhaps not picking up the quest item back then. Anyway, the waypoint leads me to a place in the shallow water of the bossfight chamber and indicates something to pick up but it isn't there.  Can anyone please help me and tell me how I can solve this problem?


Using Ubuntu 16.04, I have a problem with python3  $ python --version Python 2.7.12  $ sudo apt-get install python3 Reading package lists... Done Building dependency tree        Reading state information... Done python3 is already the newest version (3.5.1-3). The following packages were automatically installed and are no longer  required:   linux-headers-4.8.0-53 linux-headers-4.8.0-53-generic   linux-image-4.8.0-53-generic linux-image-extra-4.8.0-53-generic Use 'sudo apt autoremove' to remove them. 0 upgraded, 0 newly installed, 0 to remove and 4 not upgraded.  $ python3 bash: /usr/lib/command-not-found: /usr/bin/python3: bad interpreter: No such file or directory


Let's say I want to create a document class. Is there a way to make LaTex choose between packages (or package options) depending on the OS I'm working on?  More precisely, I want LaTeX to switch automatically between \RequirePackage[utf8]{inputenc} on Linux derivatives and \RequirePackage[latin1]{inputenc} on Windows.


The setting:  Imagine the scenario where I am searching for something and once I find it I identify it, then afterwards when I no longer need it I discard it. If at some point I need to identify it again I perform the search again and will succeed since it's still there.  The problem:  The noun for the process of identifying something would most likely be "identification".  I'm pretty sure the word "discardation" is not an actual word, and "discard" or "discardure" just leaves me wanting for something less overlapping and more commonly used.  The Question:  What would be a nice noun to describe the process of "discarding" something temporarily.  Looking at the thesaurus words like: remove, reject, cancel, reject, relinquish and the like come into play but I feel like those words have a more dramatic impact imposed behind them than I would like to portray. Something similar to dislocate perhaps, with an intention to remove. Disconnect seems like a good option yet I feel like I would have to change identify to connect if I choose to do so.


I have an image, below, that seems "soft" and I'd like to know why. Possibly it was resized from something like 3000 x 3000 and not sharpened. Possibly it's a 500 x 500 image, expanded to 960 x 960. Maybe the camera was out of focus. Maybe it was taken with a mobile phone instead of a $1000 Canon. Is there a way to determine what's wrong with it?  Thanks.


I want to empty current file so I do: touch it, remove it and touch because I do not want to remove non-existing file; example             touch "$filenameTarget"            rm "$filenameTarget"            touch "$filenameTarget"   I want to be very careful with deletes.  What is the correct philosophy here?  OS: Debian 8.5


When and why did we start using auxiliary verbs, particularly "do", to ask questions and make negatives?


What is a white noise ? What is the derivate of the Brownian motion?

Could someone explain me what is a whit noise ? In my course it's written that it's the derivate of a Brownian motion, but how can it be the derivative of something that doesn't exist ?


How to perform Visibility Analysis using QGIS?

How can I calculate Visibility using QGIS?  I have not found any suitable plugins for QGIS to do this.


I've the enum type ReportTypeEnum that get passed between methods in all my classes but I then need to pass this on the URL so I use the ordinal method to get the int value. After I get it in my other JSP page, I need to convert it to back to an ReportTypeEnum so that I can continue passing it.   How can I convert ordinal to the ReportTypeEnum?  Using Java 6 SE.


Low quality when applying hillshade on specific DEM

I've been using GIS for a dissertation project and am having a little trouble with using a hillshade on a specific DEM. My project is looking at Cyprus, and as such I've looked around and found a really helpful Mosaic to Raster DEM file that looks to be of high quality. When I run a hillshade on it however, it looks awful and doesn't really c. I know it's not an issue with this DEM, and definitely an issue with me as I have the same problem with Bathymetry data too. I've attached a couple of images of what I mean to hopefully better explain, but the gist of it is the hillshade looks awful when coloured, and nothing like it should. Similarly, this is the case for Bathymetry data, even when I alter the normal 345 angle to account for reversal. Wondering if anyone could help, would be massive boon to this project getting a few really high quality maps in there.      Above is an album to my issue. Maybe it's a colour problem? But no matter what I try, it looks ugly. Big props to the creator of the mosaic to raster - Paraskeva Charalambos, University of Edinburgh


CMD Line - Help adding time to my filename

Can someone please help me figure out the syntax to add the time to an output file's name?  I was able to get the date, but the time isn't working for me.  I keep googling it but so far I have come up empty.  I have figured out how to add it to the file itself, but I want to be able to see it in the name. The code below, is just a super simple robocopy command that I have saved as test.cmd. Everything works, everything except adding the time. Feel free to steal it if you want.  Just make sure you Google the switches so that you know what you're doing. That part is easy to find. My Code @ECHO OFF if not exist "C:\Example" mkdir "C:\Example" ROBOCOPY.EXE C:\Example Source "\\192.168.0.100\Shared Storage" /E /Z /J /NOOFFLOAD /R:2 /W:1 /REG /UNILOG+:"C:\Example Source\%date:~-10,2%-%date:~-7,2%-%date:~-4,4% Time.txt" /MT:4 exit


"him answering questions" or "his answering questions"?

Which is correct: "they agree to him answering questions" or "they agree to his answering questions" ?


Asus Eee PC 1015CX shows resolution of 800x600 in Ubuntu 12.04

I have Asus Eee PC 1015CX and I wanted to install Ubuntu 12.04, when I used the bootable USB and tried it, the only available option for resolution setting was 800x600 which looks bad on the screen.   There is no other option on the menu. How can I enable higher resolution?


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


How do I create a sword that can only break cobwebs in Bedrock Edition?

I'm trying to give myself a sword that can only break cobwebs in Minecraft (Xbox One Bedrock Edition). It isn't working and I don't know why.  I've tried other people's answers on another question, but they don't work.  How can I do this?


Trying to identify story of a girl who teleports through rings/portals

Another request to help identify a book read in my youth.  Elements I think I remember:   Certain kids can see rings or portals floating in the air. This is apparently made possible by a small extra ring of DNA unique to each of these kids' cells (I don't remember the term plasmid specifically used). These portals are invisible to most people but show up as different colors and have different qualities assisting travel. The protagonist is a girl who can see more unusual kinds of portals than other kids, though most of the other portals don't seem to have a purpose or can't be entered. I think the kids are under control of some government organization or scientists or something, but am unsure. Probably had more a feel of sci-fi than fantasy, but I don't remember a clear scientific rationale for the phenomena involved.   Unfortunately, other than maybe exploiting something unique about her own powers, I don't remember much about the plot.  Google isn't much help since there are a lot of books about portals and rings.  I probably read this in the late 1980s or early 1990s, but it may well date a decade or more earlier.  I feel like this was middle grade or young adult fiction but somehow got housed in the library with adult fiction for reasons unknown.  Any help in figuring it out is appreciated.


Is $$ 2x_1^2 + 5x_2^2 + 5x_3^2 + 4x_1x_2 - 4x_1x_3 - 8x_2x_3 $$   positively (semi)definite, negatively (semi)definite or indefinite?   My attempt:  $$2x_1^2 + 5x_2^2 + 5x_3^2 + 4x_1x_2 - 4x_1x_3 - 8x_2x_3,$$ is equal to $$(x_1 + 2x_2)^2 + (x_1 - 2x_3)^2 + (x_2 - 4x_3)^2 - 15x_3^2.$$ I've got three positive squares and a negative one, so the expression could be both negative and positive so I would answer indefinite. However, the answer is supposed to be positively definite. Why?


linux periodic system check script or utility

Is there any commonly used shell script or utility to periodically check Linux file systems for changes, such as permission or ownership changes of configuration files.   I am thinking of something similar to , that could be run weekly or daily via a cronjob and make a simple report of changes, but tailored for Linux or portable across different Unix-like systems.   I am mostly interested in Linux Red Hat, but any starting point from a portable utility or any similar OS would be great.  I looked at  and  but it seems these are APIs meant for use by application developers, not system administrators who just wish to periodically monitor changes in certain files and directories.


Quick Look sometimes shows blank panel in Mavericks

I have OSX 10.9.2 and on some photos the Preview shows blank panel instead of the image. Sometimes it opens the image, other times it's blank (for the same image).    I can't find similar reports on the web. Also is there some alternative way to do that? To integrate some third-party app to show photos when tapping space bar.


There was running malware in a host. It was using rundll32.exe to call the malware If I check in scheduled task, I got this rundll32.exe AAA.XX BBB I am sure AAA.XX is a malware file probably the type is DLL file and BBB is the command line. The problem is I cannot find the location of AAA.XX. There is no such a file in system32. I cannot use search because I access the host using remote shell with limited actions. Do you have suggestion, where's the exact location of AAA.XX?


I'm trying to run a batch file in python using the following command: os.system(r'file_path\file_name.bat')  and subprocess.run(file_path)  The os command line opens the command prompt for few seconds but shows error and closes immediately. The subprocess command line does nothing. I tried using the responses in the similar question, but none helped. Is there anything that i could be missing here?


When encrypting a message with a symmetric key, it seems like the best practice is to first encrypt the message, then run the cipher text and key through HMAC, appending the result to the cipher text. The receiver can strip off the hash, HMAC the cipher text and key, and verify that the hashes match. This tells the receiver that the person who made the HMAC had the secret key, and that the message was not tampered with.  But why can't the sender instead hash the cipher text, then encrypt the hash with the secret key? The receiver would decrypt the hash with the same key, hash the cipher text, and verify that the hashes match. Wouldn't this give the receiver the same assurance, and isn't this how it's done in public key cryptography, when the sender wants to sign the cipher text?


I'm trying to design a widget which is a dropdown single selection containing a very large set of data. Because there could be 2000 records in the dropdown. Loading them at once will make the system very slow. So below is my first path. This widget is used to select an option in the database.  By default, it looks just like a dropdown. When users click in the field, the dropdown list will open and a cursor will appear in the field. The 2000 options are divided into pages and that's why you see the pagination at the bottom.    When people type in the field, it will filter/auto-suggest matching results. The total number will reduce to 1000. If people also use the filter on the search result, it will reduce to 50.   However, I'm not sure if the pagination is really helpful to people who want to pick an option. I don't think they'll ever use pagination when there are 1000 of them. The reason I keep it here is because sometimes people might not know what to type in the field...  Here is another option: Add a "More" button at the bottom and get rid of pagination. Any thoughts, comments or suggestion?


Just searched for '1955211' in the SO search field.  Expected output: include the question/answer with ID '1955211' in the search results. If the search result set is a single question/answer, redirect to that (I seem to remember, that is already the case).  Actual output: the 'no results' page showed up.  How to fix: If the search term is /^[0-9]+$/ (or whatever a valid question/answer ID is), look up the ID database and include results with the queried ID.  Complicacies: May provide results that are not (at first sight) correlated to the search query, e.g., when searching for 127001 or 123456.  Problems steming from complicacies: If someone can't distinguish between the different result types, he should perhaps re-consider giving answers on SO.


Subtracting time to post how many minutes ago

So my current $item['date'] function gets the time and date of the post in this format Y-m-d H:i:s.  I want to display how many minutes was the post posted or if it is more than 24 hours, how many days ago was it posted OR like 0 days and 20 hours ago? something like that  Why doesn't the minus operator work here my code?  My current code:
<?php echo date('Y-m-d H:i:s') - $item['date'] ?> minutes ago


While I can post external texts into question and answer bodies, it preserves the old font style, spacing and size (although the markdown display won’t be affected by that.)   App Version: 1.6.6.2 Device: iPhone 6 OS Version: Version 11.0.3 (Build 15A432)


Access Javascript variable inside of an Apex:repeat

I am currently trying to add some customer markers to a map. I can add a single marker to the map but when I move that same logic inside of an Apex:repeat I no longer have access to the map variable.  My Javascript:  <script type="text/javascript">      function initialize() {       var mapProp = {         center:new google.maps.LatLng(52.634092,-0.148315),         zoom:10,         mapTypeId:google.maps.MapTypeId.ROADMAP       };                  var map=new google.maps.Map(document.getElementById("googleMap"),mapProp);            }     google.maps.event.addDomListener(window, 'load', initialize); </script>   My VP page:     <apex:repeat value="{!Locations}" var="local" id="mapMarkers" >     <script type="text/javascript">          var lat = '{!Locations[0].Geolocation__Latitude__s}';         var lng = '{!Locations[0].Geolocation__Longitude__s}';         var marker=new google.maps.Marker({             position: new google.maps.LatLng(lat, lng)             });                   marker.setMap(map);      </script> </apex:repeat>   The !Locations list is in my controller and just pulls the latitude and longitude from my Tree__c object:     public List<Tree__c> getLocations() {     List<Tree__c> locations = Database.query('SELECT Geolocation__Latitude__s, Geolocation__Longitude__s FROM Tree__c WHERE Geolocation__Latitude__s !=null AND Geolocation__Longitude__s !=null ');     return locations; }


how do i by pass google recovery on HTC 526?

a Friend gave mea HTC 526 but they hard reset an the phone is asking for me to give the Gmail account that's was set with the phone   an I nor  my friend don't know it so how can I skip this an set it up with my email /


Write this proposition in the form of "if p, then q"     Mary will go swimming unless the water is too cold.   I will answer:     if the water is not too cold, then Mary will go swimming.   Is this correct btw?


Execute task if tasker profile has been active for some time

How can I execute a tasker task only after a certain condition has been true for a certain time?  Normally a profile executes its task as soon as all conditions are met. I want to delay this activation, until the conditions have stayed true for some time.  E.g.    do something after the screen has been continuously off or on for 10 minutes do something after wifi xy has not been near for 10 minutes do something after cell towers x,y,z have not been near for 10 minutes.


Im jordanian and have bulgaria visa type c number entries 2  i want book flight from amman to bucharest Then back to amman with out enter bulgaria Can i do that


How would I refer to myself in a research paper? I know the use of 'I' is out of the question, so would it be 'this researcher'?


Why does Venus spin in the opposite direction?

Given: Law of Conservation of Angular Momentum.   Reverse spinning with dense atmosphere (92 times > Earth & CO2 dominant sulphur based). Surface same degree of aging all over. Hypothetical large impact is not a sufficient answer.   Assuming any object large enough to alter a planets rotation or even orbit would likely destroy most of its shape, yet Venus has retained a spherical property with a seemingly flat, even terrain indicating no volcanoes,and few if any visible meteor impacts. It would be fragmented and dispersed for billions of years.  Even the question of what meteor, comet, asteroid composition could survive traveling that close to the sun's temperature, radiation, electromagnetic energy, solar flares, or gravity to equal a mass reactionary change as to alter it's spin.


I installed Ubuntu 15.04 (64 bit) on a DELL XPS 13 (model 9343, 2015 edition - bios A03). It is a dual boot machine (Windows and Linux). I am having an annoying problem: Ubuntu randomly freezes. The screen does NOT go blank, mouse and keyboard do not work, touchpad does not work. I ran the bios diagnostic tests and found no hardware problems. My kernel is 3.19.0-16.


I was looking at the datasheet of AD620 instrumentation amplifier. It had a circuit for measurement of EMG signals.     The gain of 7, as written on the amplifier, is justified for this amplifier configuration, as Gain= (1+ 49.4kohm/Rg)  with Rg=8.25kohm. But what's the purpose of adding this additional circuit here (highlighted in green). I think it is for creating some reference. But how? And won't it cause any deviation from the gain of 7?


Letters of Recommendation - Duration Etiquette

I finished my undergraduate degree in mathematics about two years ago, and started a master's program last year. Now that I am about half way through the MS program, I am convinced that I want to get into a doctoral program. I was admitted to the master's program based upon very strong recommendations from respected scientists at the university where my undergraduate degree was obtained.    The MS program I am attending is at a small, noncompetitive institution. I am thinking that recommendation letters from this school would not be as meaningful. Also, based upon the limited scope of the research being conducted here, and my limited capacity to participate, I fear that letters from these professors might not be as strongly worded.  It is my intention to apply to several programs starting in December of this year. My question is this: Is it unreasonable to ask for my old references to "re-send" their letters of recommendation, almost 3 years after my association with them has concluded? Would it seem peculiar to the admissions board if all of my recommendation letters came from a school other than the one where I (will) have completed my MS?


How to install debian jessie-backports package after package removal using Docker?

The problem  I'm trying to use jessie-backports in a docker repository for a Ruby on Rails project using this Dockerfile:  FROM ruby:2.4.1 ENV DEBIAN_FRONTEND noninteractive ENV DEBCONF_NONINTERACTIVE_SEEN true  RUN echo 'alias ll="ls --color=auto -l"' >> ~/.bashrc RUN apt-get remove -y python RUN apt-get update --fix-missing RUN apt-get -y upgrade  RUN echo "deb http://ftp.debian.org/debian jessie-backports main" >> /etc/apt/sources.list && apt-get update RUN apt-get install -y certbot -t jessie-backports   However when I attempted to build the docker image. the following error popped up in the middle of the installation:  E: Release file for http://archive.debian.org/debian/dists/jessie-backports/InRelease is expired (invalid since 77d 3h 49min 17s). Updates for this repository will not be applied.   As of March 27 Lucas Nussbaum wrote in this  that jessie-updates and jessie-backports were going to be removed from Debian mirrors.  The blog post I mentioned stated that what I needed to do was replace:  deb http://ftp.debian.org/debian jessie-backports main   With this other commands:  deb http://archive.debian.org/debian/ jessie-backports main contrib non-free echo 'Acquire::Check-Valid-Until no;' > /etc/apt/apt.conf.d/99no-check-valid-until   So I changed the commands as follows:  FROM ruby:2.4.1 ENV DEBIAN_FRONTEND noninteractive ENV DEBCONF_NONINTERACTIVE_SEEN true  RUN echo 'alias ll="ls --color=auto -l"' >> ~/.bashrc RUN apt-get remove -y python RUN apt-get update --fix-missing RUN apt-get -y upgrade  RUN echo "deb http://archive.debian.org/debian/ jessie-backports main contrib non-free" > /etc/apt/sources.list RUN echo 'Acquire::Check-Valid-Until no;' > /etc/apt/apt.conf.d/99no-check-valid-until RUN apt-get update RUN apt-get install -y certbot -t jessie-backports   However the same issue is still present.  I also attempted to move the commands before any apt command like this:  FROM ruby:2.4.1 ENV DEBIAN_FRONTEND noninteractive ENV DEBCONF_NONINTERACTIVE_SEEN true  RUN echo 'alias ll="ls --color=auto -l"' >> ~/.bashrc  RUN echo "deb http://archive.debian.org/debian/ jessie-backports main contrib non-free" > /etc/apt/sources.list RUN echo 'Acquire::Check-Valid-Until no;' > /etc/apt/apt.conf.d/99no-check-valid-until RUN apt-get update  RUN apt-get remove -y python RUN apt-get update --fix-missing RUN apt-get -y upgrade RUN apt-get install -y certbot -t jessie-backports


archlinux: how to find a file for install with pacman?

Question is really simple: I want to get the package which contain a file,in this example I will use "ifconfig".  On Centos I use  yum --whatprovides *bin/ifconfig   On debian I can use  apt-file search *bin/ifconfig   And on Archlinux with pacman?


natbib question: Johnson 1990a, b in order of appearance

I have an issue with the natbib package.  In my reference list, multiple entries occur of the same author in the same year. I'd like to control which one is Johnson (1990a), and which one is Johnson (1990b). The BibTeX compiler creates an order for them, putting the first paper in the reference list (which incidentally is also published earlier in 1990 than the other) as 1990b.   I'd like to be able to control the a,b order, preferably without changing it manually in the .bbl file. Does anyone know how to do this? What ordering scheme does the compiler use by default?


I came across an article talking about the difference between state and country, when they mean nation, like ,  and .  The article says that the USA and the UK can be referred to as country while North Korea can only be referred to as state.  The rationale behind that is     country means people with citizen rights + elected government + land   while     state means only government.   Because in my native language, there is no difference between state and country when they are translated as nation, I am curious to know whether the point the article tries to make is true or not, or to what extent it is true.    Edit:  The people in Libya are now fighting for their rights. When they say we love Libya, they certainly do not refer to Great Socialist People's Libyan Arab Jamahiriya.  How to distinguish that Libya from the GSPLAJ? According to the article, the former may be called country while the latter may be called state.


I'm new to sculpting, and after sculpting some alien-y kinda abyssal, I'm trying to color it. However, when I change to the shading viewport, it goes kinda transparent, and when I go to the shading tab it freaks out completely. Here's some screenshots (or pictures from my phone, in this case)


Just trying to install Git on a new Kubuntu instance, getting "please insert Kubuntu 19.10 into cdrom"

I run install git and get the following error:     Please insert 'Kubuntu 19.10 Eoan Ermine - Release amd64 (20191017)'   in the drive '/cdrom/' and press [Enter]   I cannot do anything after this, it just locks up and I have to exit.   What's the problem and how can I fix it?


npm giving compatibility error in Ubuntu 16.04

I have node version 4.2.6 installed in my machine. I have successfully installed npm as well but when I use npm -v it gives the following error  ERROR: npm is known not to run on Node.js v4.2.6 Node.js 4 is supported but the specific version you're running has a bug known to break npm. Please update to at least ${rel.min} to use this version of npm. You can find the latest release of Node.js at https://nodejs.org/


I have to change  <<STORE>>SA_MASTER_YYYMMDDHHMMSS.dat file name to  SA_MASTERYYYMMDDHHMMSS.<<STORE>>. Please tell me the command in unix to achieve this  for example 0001.SAMASTER_YYYYMMDDHHMMSS.DAT should be changed to SAMASTER_YYYYMMDDHHMMSS.1 ie if the store has leading zero(0001) i have to eliminate the zeros(1)


Cartoon in which a group of teenagers fight a humanoid bug inside a virtual version of their city

I'm looking for a cartoon.  As I can remember, the story follows a group of teenagers under the guidance of a virtual, priest or monk-like man in white clothes (who always appears on a big monitor), as they fight in a digitalized version of their city.  The main antagonist is a human-like bug, and his minion is a teenager guy who can program the virtual city, where the main characters are fighting.  Not sure: most of the base situation involves the main antagonist turning the main characters' city into a virtual world.


Let $\pi$ denote a prime element in $\mathbb Z[i], \pi \notin \mathbb Z, i \mathbb Z$. Prove that $N(\pi)=2$ or $N(\pi)=p$, $p \equiv 1 \pmod 4$

Let $\pi$ denote a prime element in $\mathbb Z[i], \pi \notin \mathbb Z, i \mathbb Z$. Prove that $N(\pi)=2$ or $N(\pi)=p$, $p \equiv 1 \pmod 4, p$ is a prime.   I know that $\pi$ is prime in $\mathbb Z[i]$ implies it is irreducible. Also if $\pi$ has a prime norm, that is $N(\pi) = p$ then $\pi$ is irreducible.  For any $z \in \mathbb Z[i]$ we have $N(z) = a^2 + b^2$. Since $\pi \notin \mathbb Z, i \mathbb Z$ both $a$ and $b$ must be non-zero in the case of $\pi$. By Fermat's Two Square theorem every prime number $\equiv 1 \pmod 4$ can be written as a unique sum of two squares. I have some idea I should utilize this theorem here, but no success so far.  However I've come to a dead end. I don't know how to go on from here. Could someone help me out ?  Thanks.


While on a quest in Solstheim, I killed some wild animals. Some hunters arrived, and I kill them, like I normally do in the main Skyrim area.   Apparently, this made Frea and all the Skaal mad, they keep trying to kill me and I cant even get past the first mission.   I cannot go back to an earlier save. Please someone tell me how to have her stop trying to kill me so I can talk to her. And also tell me how I can make the other Skaal friendly again.  I'm playing on the Xbox 360. During the  quest.


I have the following piece of code:  String week = this.getIntent().getStringExtra("weekNumber"); String correctWeek = Integer.toString(Calendar.WEEK_OF_YEAR);  if (week == correctWeek) {     correct(); }  else incorrect();   They are both "3", but the comparation result is false and I don't know why:    Where is the error?


Relation between port, port number and protocol?

Is a "port"  a communication endpoint (in the transport layer)?  Is a "port number"   an address assigned to a port?  Given a port, can we change the port number assigned to it, similar to that it is possible to change the IP address assigned to a network interface? From      sockets with TCP port 53 and UDP port 53 are distinct sockets   What does the quote mean? Specifically,   Can a port be used by two transport protocols (e.g. TCP and UDP) simultaneously? (My understanding is that a port is part of a transport protocol, and can't belong to another protocol even at a different time.) Does the quote mean that a port number 53 can be assigned to a port in TCP  and to a port in UDP at different times (but not simultaneously)?


How to add repository from shell in Debian?

In Ubuntu one can add a repository via following command -   sudo add-apt-repository ppa:yannubuntu/boot-repair   As Ubuntu is based on Debian code base, I was expecting that the same would work in Debian too, but it doesn't.   What is the reason for this? Is there some other shell command I can use to achieve the same?   Note:  I know I can edit /etc/apt/sources.list, but I want to achieve this from the shell. I also want to know why the same command won't work when the code base is the same.


Some hours ago I was awarded the Good Question badge on Meta Stack Overflow:   It's a silver badge, but I didn't receive the      earn a silver badge     Seems a bug, or is it because meta badges are ignored for hats?


How to check if $\sum_{n=1}^\infty \frac 1{n!}$ is converging or diverging by direct comparison test?

$$\sum_{n=1}^\infty \frac 1{n!}$$   I think we may compare it with $\frac{1}{n^n}$, and say that $\frac{1}{n!}>\frac{1}{n^n}$. But I am not sure of the convergence or divergence of $\frac{1}{n^n}$ itself, so this turns out to be useless.  What other way is there?


I just dont want any os in my my computer,  it is distracting me from my studies. Does anyone has an idea for removing ubuntu from a single boot.


So, I have the xml file with structure:  <?xml version="1.0" encoding="utf-8"?> <Students>   <Student Id="0">     <FirstName>Robert</FirstName>     <Last>Jarman</Last>     <Age>21</Age>     <Gender>0</Gender>   </Student>   <Student Id="1">     <FirstName>Leona</FirstName>     <Last>Menders</Last>     <Age>20</Age>     <Gender>1</Gender>   </Student> <Students>   What is the best way to read(one or several elements), write, delete and update records inside a document?


What does $\!\bmod(n,x^r-1)$ mean? [in AKS primality test]

Where does a layman go to get a basic understanding of AKS primality testing. I am not talking about the optimal choice of $r$ (which I am told is the hardcore number-theoretic part of the algorithm). I mean basic things, like what does $\bmod(n, x^r-1)$ mean (how can something be mod two things?) And what does binomial expansion have to do with anything?  I can't find anything in Wikipedia that is appropriate for my level.


Cycles of length k in a complete simple graph with n vertices

Hello everyone interested. Here's a seemingly simple problem.  Suppose $G$ is a complete, simple graph with vertices $\{1,2,..,n\}$, $n\geq k\geq 3$.  How many cycles of length $k$ can we have on $G$?  The statement seems simple but I have trouble putting everything together.  So I say fix a vertex and start forming cycles with length k. But I get nowhere... What is the proper approach to this problem since counting is not easy? Is there a relevant theorem that I am unaware of?  Thanks for any help...


Why do people, incorrectly, begin a sentence with the word "But"?

I find myself editing a good number of people's questions on Stack Exchange sites in order to correct grammatical errors. A large number of these edits include fixing what appears to be the common mistake of beginning a sentence with "But". A hypothetical example would be  I have set my router up to use DHCP. But it does not seem to be working correctly and it is causing me some problems accessing the internet.  or  My computer was working fine for three years. But the other day it died.  As a (British) English teacher, seeing a "but" with a capital "B" is one of my pet hates. I am not sure why though. I think that when I was at school one of my English teachers must have emphasised that this was wrong (along with starting a sentence with "due to..." - but that is another story.) The two examples above would, obviously be correctly written as  I have set my router up to use DHCP, but it does not seem to be working correctly and it is causing me some problems accessing the internet.  and  My computer was working fine for three years, but the other day it died.  I see this mistake made a lot by non-native English speakers, although, worryingly, many native speakers do the same. Why is that? Is it an issue arising from direct translation from the mother tongue. I wonder whether it is grammatically correct in other languages to begin a sentence with the equivalent of "but", i.e. "mais", "pero", "aber" etc. I guess that I need to check my old foreign language grammar books, but I don't have them to hand. Maybe it is because the sentence has become rather long winded and the authour feels that it is time for a full stop. Do English teachers no longer teach that this is a grammatically incorrect thing to do? So, I respectfully ask this question to non-native English speakers: Why do you feel that is it OK to begin a sentence with "But"? Addendum Thank you for the answers and comments. I stand corrected. After further (pointed) research I came across this, from :  During the 19th century, some schoolteachers took against the practice of beginning a sentence with a word like but or and, presumably because they noticed the way young children overused them in their writing. But instead of gently weaning the children away from overuse, they banned the usage altogether! Generations of children were taught they should ‘never’ begin a sentence with a conjunction. Some still are. (Entry for and)  My English teacher at school was quite an agéd chap and obviously had been taught by a teacher who, in turn, had probably been educated by someone for the above epoch, or if not, then using materials derived from that time. My next question would now be, "When did the practise of forbidding the starting of a sentence with 'But' cease?" It was certainly alive and kicking in 80's Britain.


I came across with this sentence and it cast me doubt the usage of "most" and "the most"   The sentence states: "But what I remembered most is moving a lot"  Would it change the meaning of the sentence if I interchange "most" with "the most"? I am a little confused about when to use these words.  Previous to this post I searched for the difference between these words but I think I need not only the definition but examples to distinguish their usage. Thank you


show that if A is not compact, exists a function continuous and bounded without maximum or minimum

show that if A is not compact in $\mathbf{R}$ ,  exists a function continuous and bounded $f:A\to \mathbf{R}$ without maximum or minimum in A. I showed it by examples but it is not enough for my prof. Could this be demonstrated in a more general way? Does anyone have an idea?


Increasing spacing between section number and title in the table of contents

I'm using the simple ordinary \tableofcontents command to produce a table of contents, and I find that the resulting spacing between the section number and the section title is too small:    Can someone tell me how to fix this, please. My documentclass is memoir, if that matters.


How to create old looking/ cracked glass

I am looking for old looking cracked glass for a window in a shack scene. I have looked everywhere but can find a tutorial or material or model on this please can someone help me on this thanks


Minimum value of $\left(a+\frac{1}{b}\right)^2+\left(b+\frac{1}{c}\right)^2+\left(c+\frac{1}{a}\right)^2$

Given $a,b,c \in \mathbb{R^+}$ such that $a+b+c=12$   Find Minimum value of $$S=\left(a+\frac{1}{b}\right)^2+\left(b+\frac{1}{c}\right)^2+\left(c+\frac{1}{a}\right)^2$$  My Try: By Cauchy Schwarz Inequality we have  $$\left(a+\frac{1}{b}\right)+\left(b+\frac{1}{c}\right)+\left(c+\frac{1}{a}\right)\le \sqrt{3}\sqrt{S}$$  $\implies$  $$\sqrt{3S} \ge 12+\frac{1}{a}+\frac{1}{b}+\frac{1}{c}$$  Now by $AM \ge HM $ inequality we have  $$\frac{a+b+c}{3} \ge \frac{3}{\frac{1}{a}+\frac{1}{b}+\frac{1}{c}}$$ $\implies$  $$\frac{1}{a}+\frac{1}{b}+\frac{1}{c} \ge \frac{3}{4}$$  hence  $$\sqrt{3S} \ge 12+\frac{3}{4}=\frac{51}{4}$$  hence  $$3S \ge \frac{2601}{16}$$  so $$S \ge \frac{867}{16}$$  is this approach correct and any better approach please share.


I need to use some unicode glyphs relating to greek metric, namely ⎯ ⏑  ⏒   ⏓   ⏔   ⏕   ⏖, but I can't make them display on the document.  I've got  \documentclass{beamer}  \usepackage[ngerman]{babel} \usepackage[utf8]{inputenc}  \usepackage{fontspec} \setmainfont{Symbola}  \begin{document}     \begin{frame}         \begin{description}             \item[test] ⎯⏔⎯⏔⎯⏔⎯⏔⎯⏔⎯             \item          \end{description}     \end{frame} \end{document}   But on the pdf it's missing


General relativistic Euler Lagrange equation

I am learning general relativity and at some point in the lecture notes it introduces the variational form of the equations of motion, i.e. minimise the action: $$S = \int_{A}^{B} d\tau = \frac{1}{c}\int_{A}^{B} \sqrt{-g_{\mu\nu} \frac{dx^\mu}{d\lambda} \frac{dx^\nu}{d\lambda}} d\lambda$$ where $\lambda$ is a parameter for the path in spacetime. The integrand is the Lagrangian. The notes then set $\lambda = \tau$. However if they do this then the Lagrangian is obviously just a constant ($c$ in fact). So any partial or total derivatives of the Lagrangian must be zero and the Euler-Lagrange equations become vacuous. So $\lambda = \tau$ seems like a bad choice. Are my notes wrong or am I missing something?  EDIT: some have said this question is a duplicate of  and  question. Unfortunately I do not see how my question is a duplicate. The fact that the integral is path dependent (addressed in the first link) is irrelevant. For example, consider an integral for the length of a path $\int_{\gamma} ds = \int_{\gamma} L(s) ds$. Obviously $L(s) = 1$ is not a good choice for the Lagrangian. The E-L equation would be vacuous. But this is precisely the situation when you set $\lambda = \tau$. The fact that the integral is path dependent doesn't change this. And I don't see how the second link is relevant at all.


Fantasy book series with non-human races and labyrinth

I'm trying to identify fantasy book series I encountered some time ago. Here are things I remember:   it was a fantasy setting but with some s-f elements; with many worlds and possibility to travel between them; resembling  setting a little, the two main races were non-human and probably hostile to each other,  a labyrinth (?), which somehow played an important role in the plot, a protagonist was some kind of emissary and was sent on a mission to another worlds  time period: 80s - 90s    Does anyone know what it is the name of the series?


How to prove that Weyl spinors equations are Lorentz invariant?

The Dirac equation is given by:  $[iγ^μ ∂_μ − m] ψ(x) = 0$ .   We can prove that it's Lorentz invariant when:   $ψ(x) \to S^{-1} \psi'(x')$ and $\partial_\mu \to \Lambda^\nu_\mu \partial'_\nu$, where   $S(\Lambda) = 1 -\frac{i}{4} \sigma_{\mu\nu}\epsilon^{\mu\nu}$  which applying that for Dirac equation covariance that $\Lambda^\nu_\mu S \gamma^\mu S^{-1}=\gamma^\nu$   Now the Weyl spinors equations are given by:  $i \bar{\sigma}.\partial\psi_L=0,~~~~~~~(1)$  $i \sigma.\partial\psi_R=0, ~~~~~~~~~~(2)$  where $\sigma^\mu\equiv (1,\underline{\sigma})$ and $\bar{\sigma}^\mu\equiv (1,-\underline{\sigma})$  Look for instance Peskin's book "An Introduction To Quantum Field Theory"  where the Lorentz transformation of $\psi_L$ and $\psi_R$ are given by:  $\psi_L \to (1-i\theta.\frac{\sigma}{2}- \beta.\frac{\sigma}{2}) \psi_L$,  $\psi_R \to (1-i\theta.\frac{\sigma}{2}+ \beta.\frac{\sigma}{2}) \psi_R$,  How one can show that (1) and (2) are Lorentz invariant ?


prove a group of certain order is never simple

There is no simple group of order $400$.  $400=2^{4}\times 5^{2}$,so by sylow theorem, there is a 2-sylow group $A$ or 5-sylow group $B$,then by group action(left multiplication) we have a group homorphism from $G$ to symmtry groups $S_{5^{2}}$ or $S_{2^{4}}$.Kernel of these two morphisms are all normal subgroup of $G$ if they are nontrivial.It's enough for us to prove that one of these two homorphisms have nontrivial kernel.But I don't know how to prove it. Since there is an answer in mathstackexchange by using sylow theorem not group action, I think this should not be duplicated.


How to avoid infinite loop in save_post callback

I have been using this site alot for solving my problems, but this time I did not succeed in finding and answer for my problem.  I get and infinite loop when using wp_update_post inside a function that is called on save_post. I know that this is a common issue, but I can't figure out how to avoid it.  I want to save the order of my posts (which is of the post-type 'section'). So I have made a custom meta box which contain some sortable html-elements. In each element there is an hidden input tag with name='sectionorder[]'. So when I click the standard WordPress 'Update' buttom, an array containing all the ID's of the posts (in order) are send via POST. So here is the code where I retrieve the array, and wants to save the order:      // Update section sort order $sectionorder = $_POST['sectionorder']; if (isset($sectionorder)) { // Avoid error if there is no sections added yet     foreach( $sectionorder as $no => $sectionID ) {         $post_update = array();         $post_update['ID'] = $sectionID;         $post_update['menu_order'] = $no;         wp_update_post( $post_update );     } }   But the problem is that it starts an infinite loop. How do I avoid that? Maybe I can do it in a completely different way?  Appriciate your help!


What effect would a Dementor have on Lord Voldemort?

Since Lord Voldemort has become less and less human, does that exclude him from the effects of a Dementor which feeds on human emotions?   I'm not asking about what would happen if a Dementor kissed Voldemort and sucked his soul out. Dementors feed off the happy emotions of people until they're left with their worst memories. Seeing that Voldemort doesn't actually feel any happy emotions as such, will he feel the same despair and fear if he got near a Dementor? Is there anything left in Voldemort which the Dementors could feed off?


We know that Githyanki hatch from eggs from . Is there a specific source that says the Githzerai hatch from/lay eggs?


What ways can I upgrade from 17.04 (Zesty) to 18.04 (Bionic)?

I've tried a few ways online (though they seem to be different ways of doing the same thing). And I always get this message: An upgrade from 'zesty' to 'bionic' is not supported with this tool. I saw in another post on this forum, that you have to upgrade in order? Meaning, I apparently need to upgrade my 17.04 installation to 17.10, and then I can upgrade to 18.04. Which is fine, I have enough free time to do that, however... how? How do I upgrade from 17.04 to 17.10 now that 18.04 is out?  And I would highly appreciate a solution that doesn't just involve reinstalling the OS. Because while I do already have a flash drive with 18.04 on it via Rufus, I do not have the knowledge of Linux required to get all my save data for my applications (namely games), and back it up, because I don't understand where Linux and it's applications store their data.  Finally, I don't know if this matters at all, but just so it's on the record: this is a dual boot setup. PC had Windows, before I slipped Ubuntu in the side :p .  -- I would like to reiderate, that I want to upgrade from 17.04 to 17.10, and then from 17.10 to 18.04. I would also like to point out that the official upgrade tutorial does not seem to bother mentioning that 17.04 users will have a hard time (or possibly even can't!) upgrade, which is odd to me only because it does mention that for users on 15.10, to read an upgrade notes page on the Ubuntu site. So they are aware of people trying to do large leaps in versions.  EDIT:  For this:   I get an error when executing the second command in the answer:  E: Problem executing scripts APT::Update::Post-Invoke-Success 'if /usr/bin/test -w /var/cache/app-info -a -e /usr/bin/appstreamcli; then appstreamcli refresh-cache > /dev/null; fi' E: Sub-process returned an error code   Another Question:  If I put a 17.10 iso on a flash drive, and booted from that, would I be given the option to upgrade to that version? The reason I ask, instead of just trying it myself, is because I'd rather not waste the time downloading such a large file, for it not to work.


How can I have a horizontally shaded frametitle in beamer?

This question is similar to . I want to achieve the horizontal shading effect in the frametitle and when I use  \setbeamertemplate{frametitle}[horizontal shading] [left=red, right=white]   I get compilation errors:  LaTeX Error: Missing \begin{document}. [[]   Vertical shading seems to work just fine.


Want to create super user (administrator) account?

Have installed ubuntu 13.04. While login, i am unable to login using user name and password.   So i am loging in by using guest account.   I need to create the admin account now. can any one help me .   I have also tried sudo su but it says, "Unable to change to sudoers gid :operation not permitted."  I have tried su also but when I enter the password it says, "Authentication failure".  Regards Vijay


Can I use 1333 MHz and 1600 MHz RAM together?

I currently have 2x1GG 1333MHz DDR3 strips. I plan to purchase a further 2x4GG 1600Mhz strips. Will I be able to use both sets of RAM in my PC together? Will they both be limited to 1333Mhz?   Old RAM: Corsair cm3x1024-1333c9dhx New RAM:  Motherboard:


Hat is your way to organize and archive works

what is the best way or your way to organize file on windows to save your old design works. do you use a particoular software like adobebridge or as i do by orgnizing files in folders? I'm always in doubt if is better by writing a date like 20180211 or by committant.


What is the difference between / and // in terminal commands

While going through the terminal just changing the directory with / and // it shown the same contents of root directory then what's the difference in both of them


How to convert MS Word 2007 file into JPG file?

How do I convert an MS Word 2007 file into a JPG file?  I need a method that will work off-line for Windows XP, preferably that does not require installing software.


Let $n$ be some positive odd number. Prove, in terms of the pigeonhole principle, that there exists some positive integer $k$ such that $n\mid 2^k-1$.


What are the most suitable filter holders for my Samyang 14mm autofocus prime lens?

I've looked into the ones from Haida and Nisi which are both suitable, though they're quite pricey for me currently - does anybody know of any cheaper possible alternatives? I understand there's the 160mm specifically made for use with this lens, though obtaining filters for it is difficult and limited. I'm hoping for something which may be cheaper than both Haida and Nisi, and still suitable for the 14mm lens. Thanks!


Show that the congruence equation  $x^8 \equiv 16 \pmod p$ has a solution for every prime $p$. Let $g$ be a primitive root， then the equation is equivalent to $8  \ ind_g(x)\equiv 4 \ ind_g(2) \pmod {p-1}$. It suffices to show that $2\mid ind_g(2)$.


Simplify this expression: $ \left((p\to q) \land (q \to r)\right)\to (p \to r)$

how to prove that expression is a tautology by using law of logic?? Thank you in instant


I am trying this math to solve.the equation is like this:  $2^x=4x$  Here $x=4$ should be the answer.  But How can I derive it in a mathematical way?  I am failed to solve it my general algebra.How can I use logarithm here to solve it?  Thanks in Advance.


Referenced Objects in List Change on Contents Change, but Not Setting to NULL

I have this code which adds some objects to an ArrayList. Then, from the List, in Step 1, I modify the contents of these objects -- and the backing objects themselves also change, which works. Then, in Step 2, from the List I set my objects to NULL. The list changes - I can see its elements are NULL, but the backing objects do not change. Why is that?  My expectation: a, b, c are set to NULL.  public class Test {  static class Student {     String name;     int age;      public Student(String name, int age) { this.name = name; this.age = age; };     public String getName() { return name; }     public int getAge() { return age; }     public void setName(String name) { this.name = name; }     public void setAge(int age) { this.age = age; } }  public static void main(String[] args) {     Student a = new Student("John", 20);     Student b = new Student("Mary", 21);     Student c = new Student("Bill", 22);      ArrayList<Student> students = new ArrayList<Student>();     students.add(a);     students.add(b);     students.add(c);      // STEP 1: Changing contents from list: THIS WORKS - Referenced objs change (a, b, c)     for (int i = 0; i < students.size(); i++)                    students.get(i).setName("NEW NAME");       // STEP 2: Setting to null from list: DOES NOT WORK - Referenced objs do NOT change (a, b, c)     for (int i = 0; i < students.size(); i++)         students.set(i, null);   }


Paradox of General Comprehension in Set Theory, other than Russell's Paradox

As is well known, the General Set Comprehension Principle (any class is a set) leads to the Russell Paradox (the class $x \notin x$ cannot be a set). As a result, set theories must restrict the Comprehension Principle to avoid self-reference. For example, in the case of ZFC, this is done by enumerating a small list of "safe" comprehension schema such as Separation.  Does General Comprehension lead to other types of paradox than Russell's? Or is this basically the only thing that can go wrong?


Any integral or series to prove $\frac{1}{\sqrt{3}}>\gamma$?

I recently noticed that these two numbers are remarkably close:  $$\frac{1}{\sqrt{3}}-\gamma=0.000135\dots$$     Are there any integrals or series which can prove that $\frac{1}{\sqrt{3}}>\gamma$?   Meaning that (as usual in such cases) the function under the integral has to be non-negative and the value should be proportional to the difference of these numbers.  The same goes for the series (strictly non-negative terms).  A good overview for the inequalities with $\pi$, like $\frac{22}{7}>\pi$, can be found in .    A . But I don't consider my question a duplicate, because the linked question is more general.


Installing 2 versions of Ubuntu on same hard drive?

I have a dilemma and I don't know what to do.   Currently I have Ubuntu 14.04 64 bit installed along side Windows 7 64 bit and everything works wonderfully.   I recently started a course about Assembly on Linux and the professor recommended downloading Ubuntu 12.04 32 bit.   I downloaded the iso file and loaded it on to a USB.   When I first installed Ubuntu 14.04, it gave me the following 3 options:  1) install Ubuntu alongside Windows  2) delete Window and install Ubuntu 3) Something Else   I choose the first option. However, when I attempted to install Ubuntu 12.04 32bit along side Ubuntu 14.04 64 Bit and Windows 64 bit, the first option was gone. Instead I was given the following 3 options:  1) Delete 14.04 and install 12.04 in its place  2) Delete both 14.04 and Windows 7 and install 12.04 as replacement  3) Something Else   My question is this: is it advisable to install Ubuntu 12.04 32 bit along side Ubuntu 14.04 64 bit and Windows 7 as the Ubuntu Installer no longer gives me this option? Should I just go ahead and replace 14.04 with 12.04 for the duration of time that I would need it. I don't want to delete 14.04 but I will if need be. I also like the current Dual boot option Ubuntu has put in place so if making a 4th partition through way of "Something Else" would delete that, I would much rather delete 14.04 to make room for 12.04. Again my preference would be to have Ubuntu 12.04 32 bit appear alongside Ubuntu 14.04 64 bit and Windows 7 when I boot my computer, but short of that, I would settle for Ubuntu 12.04 32 bit appearing alongside Windows 7 for the time being. I look forward to your advice.