Why the arc when bonding-on during high voltage repairs?

When working on high voltage power-lines via helicopter the technician will "bond-on" with a steel wand called a hot-stick. During this process an arc is conducted from the line to the wand. Now, since the helicopter is floating both literally and electrically, why is there any potential between the line and the wand?  My guess is that because of the alternating electric current in the power-line there is therefore an alternating expanding and collapsing magnetic field present in close proximity to the helicopter. This sets up a charge polarization in the frame of the helicopter 180 degrees out of phase with the current and therefore an electrical attraction occurs which produces an electric potential.  If this is true, even though the electrons are not free to move in a bird (as they are in the metal helicopter frame) they are able to rotate and still set up a charge polarization (much like a charged balloon sticks to a wall) and therefore when a bird "bonds-on" to a wire don't you think they feel a little tingle at first?  One other thing. Is it true that by virtue of the fact the the helicopter circuitry is an isolated one, they can bond-on to either line and that line will be the ground reference for the ground of the helicopter circuitry?


How would we tell antimatter galaxies apart?

Given that  galaxies are theoretically possible, how would they be distinguishable from regular matter galaxies?  That is, antimatter is equal in  and all properties, except for the opposite reverse charge of the particles, identical to regular matter. Hence a star composed of antimatter hydrogen would fuse to anti-helium in an analogous way to our own Sun, and it would emit light and radiation at the same wavelengths as any regular matter star and would cause the same gravitational forces for planetary systems to form as in any other star system.  Hence, what would be a telltale sign if you were observing a galaxy made up entirely of antimatter?  Also, is there any evidence for that half of all galaxies are not made of antimatter -- while general theories currently assume that there is an imbalance of matter over antimatter in the universe, then what is the rationale for not assuming that there is in fact an even balance between the two?


How to enforce integrity when joined tables share a foreign key?

Consider the following table structure:  UserGroup(ie. 'Admin')     ID = 'Admin'     ApplicationFK = 'App1'  JoinTable     UserGroupFK = 'Admin'     PermissionFK = 'Approve'     PermissionValue = 'READ'  Permission(ie. 'Approve')     ID = 'Approve'     ApplicationFK = 'App2'  UserPermission     UserFK = 'John'     PermissionFK = 'Approve'     PermissionValue = 'WRITE'  User     ID = 'John'   Where you have a jointable between UserGroup and Permission, with both UserGroup and Permission having foreign keys to Application.  Is there any way to enforce integrity, to avoid the situation above, where the ApplicationFKs don't match? I cannot simply remove one of the Foreign Keys, as it is possible to have a Permission without any UserGroups, and possible to have a UserGroup without any permissions.


File upload form style for all browsers    I use this JSF code for the form  <h:inputFile id="fileToUpload" value="#{contacts.file}"/>     <h:commandButton value="Upload" action="#{contacts.upload()}">         <f:ajax execute="fileToUpload" />     </h:commandButton>   How I can make the form to look like in one style for all browser?


I tried using chemfig but I've run into a problem. For example I tried drawing a methane molecule with this code:  \documentclass[a4paper]{article} \usepackage[czech]{babel}       % czech \usepackage[utf8]{inputenc}     % unicode UTF-8 \usepackage{chemfig}  \begin{document}     \chemfig{C(-[:0]H)(-[:90]H)(-[:180]H)(-[:270]H)} \end{document}   Instead of this    it only draws this    If I convert the DVI file to PDF it becomes this    I've gathered that it doesn't draw the bonds (duh!) and that it might be caused by me using the Czech babel thingie. I'm using LaTeX on Debian 9.  SOLVED: Instead of compiling by just latex test.tex I should have used pdflatex test.tex.


Trip booked through Vayama: Can I travel without the credit card used to book it?

My company has paid for flights for my family to travel home this summer. They purchased them online through Vayama (fingers crossed). In the e-tickets I received it says specifically that I do not need to show the credit card at check in.  Having read a bunch of complaints about this company, is the information the've given me correct? I'd like to be 100% certain as I gather their customer service is somewhat lacking in service. If it's true and I'm in the clear, is the reason because it's a travel agent and not an airline?


necessary condition of improper integral

Does a function's limit when x goes to infinity must be zero for its integral to converge?  I had proved in my homework that if the function is non-negative, it's not necessarily true.  Now I read a solution that uses this as a fact - For an improper integral to converge, function's limit must be zero.  I hadn't found it in my books and notebook, and I can't find a reliable place says it is.  any help would be appreciate,  thanks


Can't Install anything from Ubuntu Software Center in Ubuntu 15.10

I just recently upgraded from Ubuntu 15.04 to Ubuntu 15.10, and now I can't install any software from Ubuntu software center or Terminal.  When I update, it is updating perfectly, but when I try to install any software from the Ubuntu software center, It says "Check you Internet Connection". The screenshots are attached.


From whom can I buy travel insurance if I don't "live" anywhere?

I am an Australian citizen, currently living in Singapore and I want to travel through Europe and the USA over the next six months. I will be leaving Singapore permanently and my intent is to ultimately land back in Australia, at least for a while, but this may not happen.  From whom can I buy travel insurance? Most consumer travel insurance plans which offer the type of cover I want (Covermore et al) assume you have a "country of residence". Effectively, I don't and that would invalidate my policy.  As a bonus, I'd prefer if I could specify I'll only be in the USA for three weeks and only pay the extra premium for that time, rather than it doubling the cost for the whole six months.


In the Deathly Hallows:     "No, he's not dead," said McGonagall bitterly. "Unlike Dumbledore, he was still carrying a wand...and he seems to have learned a few tricks from his master." With a tinge of horror, Harry saw in the distance a huge, batlike shape flying through the darkness toward the perimeter wall. (DH pg 599/482)   In the Goblet of Fire:     “Maybe he didn’t want you to get there!” said Ron quickly. “Maybe - hang on - how fast d’you reckon he could’ve gotten down to the forest? D’you reckon he could’ve beaten you and Dumbledore there?”   “Not unless he can turn himself into a bat or something,” said Harry. “Wouldn’t put it past him,” Ron muttered.   So I always assumed Snape transformed into a bat when he jumped.   Then I saw on this site and wikia that many people think he could fly like Voldemort.  My question is: is there canonical proof that Snape could fly without metamorphosis?


My problems: Windows 7 is not working and GRUB is "gone". This is what's happend:  Note: my OS is in Norwegian so I tried to translate it as good as I can.   I'm on the internet when there come up a notification that there's only ~2Gb of free space on my hard drive. Windows asks me if there's something I can delete. I choose some folders and delete them. I reboot to windows and a startup repair thingy comes up but can't find and/or repair the problem(s). In the diagnistics and repair details log is says (among other things) "Boot Manager can't find OS loader". There's 2 failed tests at the bottom: File repair, failed, error code 0xa; Repair of data storage for startup configuration (?), failed, error code: 0x2. I found somewhere to try some commands: bootrec /fixmbr, bootrec /fixboot, bootrec /scanos and bootrec /rebuildbcd, rebooted but nothing had changed. I could still get to Ubuntu from GRUB. Then I tried to activate a partition (at the time I didn't know what that would do). I used diskpart --> list disk --> select disk X --> list partition --> select partition X (here I didn't know which partition to activate, so I made my best guess (the biggest primary), which was wrong. When I rebooted it is said something along: can't find a OS. There was no GRUB. I found a lightweight linux (puppy linux), got it on a usb, live booted, activated partition no. 1 on the hard drive, rebooted, and now it goes straight to windows (without the GRUB), to the startup repair program.   This is where I am now. Back to the beginning, only worse.  I don't know what info you'll need, so just ask. Also I'm quite new when it comes to partitioning and the like.  What partition should be active? I've got 2 primary, 1 extended and 2 logical (ubuntu?)


Why would I feel more balanced when I ride my bike fast?

When I am a kid I would somehow feel more balanced when I ride my bike fast and feel less balanced when I ride my bike slow (when I am still learning how to ride). Is it a personal thing or there is some scientific reason behind it?


How do I run a windows executable in linux shell script?

I have an executable program (no source code, just the compiled executable) that was made in windows (.exe extension).  It doesn't use any graphics... it simply reads and writes files.  I want to be able to run it in a linux shell script so that I don't have to switch operating systems to get my output.  Is there a way to use or convert the executable for linux operating systems?


How many concurrent AJAX (XmlHttpRequest) requests are allowed in popular browsers?

In Firefox 3, the answer is 6 per domain: as soon as a 7th XmlHttpRequest (on any tab) to the same domain is fired, it is queued until one of the other 6 finish.  What are the numbers for the other major browsers?  Also, are there ways around these limits without having my users modify their browser settings?  For example, are there limits to the number of jsonp requests (which use script tag injection rather than an XmlHttpRequest object)?  Background: My users can make XmlHttpRequests from a web page to the server, asking the server to run ssh commands on remote hosts.  If the remote hosts are down, the ssh command takes a few minutes to fail, eventually preventing my users from performing any further commands.


What do we really mean by "Statistically Significant" results?

According to Wikipedia,  A result has statistical significance when it is very unlikely to have occurred given the null hypothesis  does that mean if our alternative hypothesis is true we will call our results "Statistically Significant"? which certainly shouldn't be the case.


I'm new for what about j2EE and I'm moving my first steps with servlet and EJB.  I use Netbeans, Glassfish. When I pass my data (I want to view in my JSP the data in the table Products on postgress and the connection I sure that works)  from servlet to JSP I have a strange Null Pointer Exception.  This is the processRequestMethod in the Servlet class:          protected void processRequest(HttpServletRequest request,HttpServletResponse response)         throws ServletException, IOException {           List<Products> list=new ArrayList<Products>();         list =  productsFacade.findAll();           request.setAttribute("list", list);          String arg = "/" + this.getServletName() + ".jsp";         RequestDispatcher dispatcher = this.getServletContext().getRequestDispatcher(arg);         dispatcher.forward(request, response); }   the method findAll():  public List<Products> findAll()     {       return em.createQuery("SELECT p FROM Products p").getResultList();     }   Instead the JSP is this:  <%@page import="java.util.ArrayList"%> <%@page import="entities.Products"%> <%@page contentType="text/html"%> <%@page pageEncoding="UTF-8"%> <%@page import="entities.Products_"%>  <%@page import="java.util.List"%> <%     List<Products> list=new ArrayList<Products>();     list = (List<Products>)request.getAttribute("list");  %>  <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"     "http://www.w3.org/TR/html4/loose.dtd">                 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">          <title>JSP Page</title>
Content of my Table
      <%            if (list != null)            { for (Products e: list)               { out.println(e.getName() + " " + e.getPrice() + "
"); }           }                   %>                 Why my list is NULL ?


Email issue with output of bash script blcheck

Bash script blcheck from github format issues with emailing output  Console output displays correct, but when sent to email via mailx will on go as attachment, not to body.     33%%  dnsbl.inps.de                                     ✓     50%%  xbl.spamhaus.org                                  ✓     Output to file or email example: 16%%  dnsbl-3.uceprotect.net  ^MESC(BESC[m  16%%  dnsbl-.uceprotect.net      ✓ESC(BESC[m     Advise pls on how can I correct the format in file & email ?   CMD that's not sending to eamil body:  sh blcheck -v xx.xx.xx.xx | mail -s "server-blcheckdate" user@email.exampel  script:      After assistance of @john1024 & @cas & previous post  below cmd resolved issue.    CMD: ./blcheck-l -v xx.xx.xx.xx | perl -pe 's/\e([^[]]|[.*?[a-zA-Z]|].*?\a)//g' | col -b | mail -s "blcheck-l -v `date`" email@address   darko-poljak has submitted a pull request on github with a new option to make output friendly for non interactive use.


Why do we need to use the builder design pattern when we can do the same thing with setters?

public class Employee {     private String name;     private String address;     private int id;      public Employee() {         // TODO Auto-generated constructor stub     }      @Override     public String toString() {         return "Employee [name=" + name + ", address=" + address + ", id=" + id + "]";     }      public String getName() {         return name;     }      public void setName(String name) {         this.name = name;     }      public String getAddress() {         return address;     }      public void setAddress(String address) {         this.address = address;     }      public int getId() {         return id;     }      public void setId(int id) {         this.id = id;     }  }  public class Main {      public static void main(String[] args) {         Employee e = new Employee();         e.setName("Priyanka");         Employee e1 = new Employee();         e1.setName("Rahul");         e1.setAddress("Delhi");         System.out.println("Value of e :"+ e);         System.out.println("Value of e1:"+ e1);     } }


Adding a total time derivative to a Lagrangian

I'm aware there are many posts regarding this topic, yet I haven't found an answer to this specific question there.  Say we have a Lagrangian $$\mathcal{L(q,\dot q, \ddot q, t)}$$ We know that adding a total time derivative of some $F(q,t)$ to a "standard Lagrangian" - one that doesn't depend on $\ddot q$, doesn't change the actual motion, but what about this instance? Can we add a more general function - one that depends on $\dot q$ for example and still get the same motion?


How do you make an image emission without washing out the image?

I am trying to make a computer monitor. This means I have to have an image texture for the screen. My image texture is currently connected to an Emission BSDF shader. Unfortunately, when the emission is bright enough to emit light, the image is white-washed. I tried adding a Brightness/contrast node to the image before pushing it into the Emission BSDF, but it seems to directly counter the Emission's strength.  The desired light level   The desired image brightness


Ring homomorphisms $\mathbb Z[x]\rightarrow \mathbb Q$

I'm supposed to find all the ring homomorphisms $\mathbb Z[x]\rightarrow \mathbb Q$.  Here's my attmept: $\mathbb Z[x]$ is generated by $\left\{ x^n \right\} _{n\geq 0}$, so the images of the generators determines the homomorphism. Since ring homomorphisms also respect multiplication, the images of $1,x$ determine everything. Homomorphisms respect units, so the image of $x$ determines our homomorphism. Hence, the only homomorphisms are the evaluations: for each $q\in \mathbb Q$ we have $\mathrm{eval}_q:\sum_na_nx^n\mapsto \sum _n a_n q^n$.  Is this correct? If so, isn't the codomain completely irrelevant? It seems we can say the same for any ring $R$ in place of $\mathbb Q$.


I would like to place a lower limit under two consecutive \sums, somewhere in between. So I have \sum_{j=1}^{\infty}\sum_{k=1}^{\infty} and would like to place j>k in the lower limit between the two sums. I believe the multiple integral operator has this kind of functionality.


I work with both pictures and schematics, and instead of "figure", I want "Picture" or "Schematics" to show up. Thus I use \renewcommand as shown below:  \renewcommand{\figurename}{Picture} \begin{figure}[htp] \centering \includegraphics[scale=1.0]{my_picture.png} \caption{This is my picture} \end{figure}  \renewcommand{\figurename}{Schematics} \begin{figure} \begin{tikzpicture}     code \end{tikzpicture} \caption{This is my schematics} \end{figure}   The result of the caption would be:   Picture 1.1 : This is my picture  Schematics 1.2 : This is my schematics   meaning that they are enumerated commonly, starting from 1. Is there a way both of them to have individual enumeration, such as    Picture 1.1 : This is my picture  Schematics 1.1 : This is my schematics Picture 1.2 : This is my picture  Schematics 1.2 : This is my schematics etc ......


Identify this YA book series about dragons, acid blood, and dangerously cold nights

I'm trying to remember the name of a series of books about a boy who works with dragons.  Dragon's blood (or maybe it was slobber?) is acidic, and the children who wrangle these dragons often end up with deep pock marks.  On this world, days are like ours but nights get very cold, requiring anyone stuck outside to find a shelter until dawn (not the false dawn)  The other thing I remember is that in one of the books by slicing open a dragon and spending the night, the character emerged with special dragon powers.


Quickest way to check whether or not file exists

The way I'm using just involves trying to fopen() the file to be checked,  /* --- does file exist??? --- */ char    fname[999] = "whatever";        /* constructed during execution */ FILE    *fp = NULL;                     /* try to fopen(fname,"r") */ int     isfilefound = 0;                /* set true if fopen() succeeds */ if ( (fp = fopen(fname,"r"))            /* try to fopen() for read */ !=    NULL ) {                          /* succeeded */   isfilefound = 1;                      /* set file found flag */   fclose(fp); }                         /* and just close the file */   Is there a quicker, less resource-intensive, way?... A specific way for unix/linux? A Windows way? And preferably, a portable posix-compliant way (as above presumably is)? It's being done lots (1000's) of times, so I'd prefer not to be unnecessarily opening and closing files for no good reason.  ----------------------------------------------------------------- Edit Okay, based on answers below, I put together the following little function intended to check whether or not file (already:) exists in a posix,windows,other portable way...  /* ==========================================================================  * Function:    isfilexists ( path )  * Purpose:     check whether file at path exists  * --------------------------------------------------------------------------  * Arguments:   path (I)        pointer to null-terminated char string  *                              containing "path/filename.ext" of  *                              file whose existence is to be determined  *                              (path is relative to pwd unless explicitly  *                              absolute by initial '/' or other syntax)  * --------------------------------------------------------------------------  * Returns:     ( int )         1 if file at path exists, or 0 if not  * --------------------------------------------------------------------------  * Notes:       o conditional compiles for various systems,  *                depending on whether POSIX or WINDOWS is #define'ed...  *              o ...method used:  *                1: use access() on Posix systems,  *                2: PathFileExists() on Windows systems,  *                3: fopen() on any other systems.  * ======================================================================= */ /* --- entry point --- */ int     isfilexists ( char *path ) { /* ---  * allocations and declarations  * ------------------------------- */ int     isexists = 0;                   /* set true if file at path exists */ FILE    *fp = NULL;                     /* fopen() for non-posix,windows */ #define POSIX                           /* just for testing */ /* ---  * determine whether file at path already exists  * ------------------------------------------------ */ #if defined(POSIX)                      /* posix-compliant system... */   #include <unistd.h>   if ( access(path,F_OK) == 0 )         /* file at path exists */     isexists = 1;                       /* so set file exists flag */ #else   #if defined(WINDOWS)                  /* Windows system... */     isexists = PathFileExists(path);    /* set flag if file at path exists */   #else     /* --- fopen() for any other non-posix, non-windows system --- */     if ( (fp = fopen(path,"r"))         /* try to fopen() for read */     != NULL ) {                         /* succeeded */       isexists = 1;                     /* set file exists flag */       fclose(fp); }                     /* and just close the file */   #endif #endif return ( isexists );    /* back to caller with 1 if file at path exists */ } /* --- end-of-function isfilexists() --- */   The access() and fopen() methods tested and work okay. Unable to test PathFileExists() for windows. And I still want to figure out what #define'ed symbols to automatically and unambiguously check for conditional compiles.


Problem in recognizing correct definite/indefinite articles out of context

I have read some grammar points about definite/indefinite articles, but I still have problems recognizing the right choice in questions requiring them. I know sometimes I can omit articles but I don't know exactly when.(Maybe this is the most confusing point for me!)  For example:     It would be difficult to imagine---life without---telephone.   Answer:(zero article/the)   Why not?(zero article/zero article)    Why "the" is needed here?      ---government is now insisting that --- math is taught with traditional methods.   Answer:(The/zero article)   Why not?(zero article/zero article)    Why "the" is needed here?      ---company needs to make sure that it is earning --- profit.   Answer:(A/a)    Why not(zero article/a)? Isn't company a general thing? Or maybe any special company?(using "the") We don't have any context here to understand what it really means.   Same things here:   I don't mind---airport;it's---flying that I hate.(the/the) or (the/zero article)   During---spring semester,---chemistry will not be offered.(the/zero article) or (zero article/zero article)      ---Microscope was invented by him.(the/zero article)   Can someone please provide information or resources to get better answers?


What changed in apache2 from saucy to trusty for projects in /var/www

I have some web roots in directories x,y,z, etc. in /var/www/, some of them (not /var/www/) are mounted with options rw,bind,uid=301,gid=301 (301 is uid of user www-data and gid of group www-data). This worked very well in default apache2 of saucy, but no longer with upgraded version in trusty. All permissions of all files and directories under /var/www/ are owned by www-data:www-data. Changing all permissions to 777 (and restarting service) didn't help! I never changed any settings in /etc/... or somewhere.  EDIT: I'm getting 404 error when I request under http://localhost:80/x (error page suggests that apache is running: Apache/2.4.7 (Ubuntu) Server at localhost Port 80). No substring error or fatal in /var/log/apache2/error.log or /var/log/apache2/access.log. netstat -tupln shows that apache2 is running on port 80.  Any ideas?  EDIT 2: Now the pages are also broken with lighttpd (don't have any CSS layout and edit links are not shown in mediawiki (this has been a behavior caused by malious redirection of apache, but can no longer be fixed by requesting the page under different hostnames)). Apache behaves as described before


Repartitioning Internal Memory of Android Device

How can I repartition my device such that the storage for device internal usage (i.e application storage or internal memory) can be increased in lieu of decreasing the User available memory.  Currently, I have:   Internal memory = 740 MB User Available Space = 2.0 GB   How can I repartition to move some Phone Storage/User Available Space to Internal Memory?  I have an External SD card for Media Storage. So, I don't require 2 GB in the phone storage.


Prove that $x^2+y^2=z^n$ has a solution $(x, y, z)$ in $\mathbb{N}$ for all $n\in\mathbb{N}$  I tried to prove this by induction, but couldn't. ( This was probably because the solution for some $n$ isn't necessarily related to the solution for $n+1$)  I can't seem to see any other way other than induction for proving the statement. Any help/hints on solving this problem, or any alternative approach will be highly appreciated :)


Cannot write text in a file when using here-document

This command doesn't seem to work in my script, how can I decide in which file I want this text, if I just create a file with the following command  touch $name   I want the text to be in the file $name that I just made in my script.  cat <<'EOF' Data... EOF


How do I run a command before or after every command written in the console?

I want to run a command before and after every single command that gets executed in a terminal (i.e. clear before and then reset). I want this to happen automatically and not with a short alias or similar.  I have looked into bashrc and /usr/share/bash-completion/bash_completion although the latter seems to be just for the auto completion feature with the Tab?   Where should I make my changes?


Animating plane with position, rotation and scale from data inside a text file

I want to animate a plane xyz coordinates, its scale on xyz and its rotation on the z axis based on a text file data where each line its a frame.  Example text file:  2265.48 563.242 0 166.402 166.402 100 7.3225 2266.61 562.668 0 166.529 166.529 100 7.32268 2267.35 562.864 0 166.622 166.622 100 7.32859 ...   Where the data is organized like this:  [x coordinate] [y coordinate] [z coordinate] [x scale] [y scale] [z scale] [z rotation]   I dont have experience in python so i would like a helping hand if possible.


Is it possible to get an inescapable question ban?

On Stack Overflow, I have been question banned, and it seems nearly impossible to get unbanned. A moderator keeps deleting my downvoted questions...


What will happen to my reputation when the Community Wiki status of a post is reversed?

A per the Community Wiki ,      The original author keeps the reputation gained (or lost) before their   post entered community mode.      The original author can flag the post to moderator attention for   re-convert the C.W to normal post, the moderators will take action on   that.   If the Community Wiki status of a post is reversed, what will happen to the reputation of votes (Up/down) gained by the post at during its time as a Community Wiki?


How do I spawn a zombie with the closest player's name MCPE

So I need to have a zombie with the closest player's name but I don't know how to do it anyone that can help? I think it would be something like this: /summon zombie ~ ~ ~ {name:@p}


Automatically keep current version of config files when apt-get install

I need to automatically install a package with its config file already present on the server.  I'm looking for something like:  apt-get install --yes --force-yes --keep-current-confs mysql-server  Probably a dumb question but I can't find such an option.


Code block markdown missing from question & answer summaries

The answer summaries shown in search results appear to strip out code block markdown from the text. For example, the second item in  doesn't show the code block markdown content of this phrase:     "As you remove characters, Cleaner becomes shorter, so you're likely to reach a point where x is too large."


Different output when calling toString on the same StringBuilder instance

I was testing around Strings, and I came up with below code:  public static void main(String[] args){     StringBuilder sb1 = new StringBuilder("Cuba");     String str1 = sb1.toString();     // n1     System.out.println(str1 == str2); }   On n1 if I place:  String str2 = sb1.toString();   I get false. However if I place:  String str2 = str1;   I get true.  I am not sure why this is happening: both codes are referring to the same instance, therefore, both output must be true.   Any idea why both output differ? I know how to compare Strings, I am just curious about the reason why the result differ.


The difference in form of the term and counter-term in the renormalized Lagrangian

Consider, for example, the renormalized free field $\phi$-scalar Lagrangian (The question applies also to interacting $\phi^n$ theories, but that's not the issue):  $$\mathcal{L}=Z_2 \left(\partial_\mu\phi\right)^2 -Z_mm^2\phi^2=\mathcal{L}_0+\delta_2\left(\partial_\mu\phi\right)^2-\delta_m\phi^2$$  Where: $$\mathcal{L}_0=\left(\partial_\mu\phi\right)^2 -m^2\phi^2$$  The Feynman rules are:   My question is why are they different in form? Why the original term $\sim\frac{i}{p^2}$, yet the counter term $\sim p^2$.  Remark: The mass term can be disregraded in the answer, since I've established that by taking the mass as an interaction to a free-massless theory, we can take the massive-interaction $\sigma(p^2)$ as:  $$\sigma(p^2)=\frac{i}{p^2}+\frac{i}{p^2}\left(-im^2\right)\frac{i}{p^2}+\frac{i}{p^2}\left(-im^2\right)\frac{i}{p^2}\left(-im^2\right)\frac{i}{p^2}\dots=\frac{i}{p^2-m^2}$$  Thank you in advance.


How are neutrinos massless? Could they or at least some of their forms be a potential candidate for Dark matter?

I am particularly new to this subject. Can neutrino physics be understood by a 10th grade?


How to better cast a char to int keeping the number value and not the ASCII value?

I have just wrote a code(c#) for my sample exam in C# basics study.  Еven though I was able to write it correctly and receive all points, I am not quite satisfied with the way I have used to cast the char ASCII value to the desired int value. I am asking for a better way to express the following code:  using System;  namespace MultiplyTable {     class Program     {         static void Main(string[] args)         {             //Input:             string inputNumber = Console.ReadLine();              //Logic:              int firstNumber = 0;             int secondNumber = 0;             int thirdNumber = 0;              for (int i = 0; i < inputNumber.Length; i++)             {                 firstNumber = inputNumber[0] - 48;                 secondNumber = inputNumber[1] - 48;                 thirdNumber = inputNumber[2] - 48;             }              for (int p = 1; p <= thirdNumber; p++)             {                 for (int j = 1; j <= secondNumber; j++)                 {                     for (int k = 1; k <= firstNumber; k++)                     {                         Console.WriteLine($"{p} * {j} * {k} = {p * j * k};");                     }                 }             }         }     } }   The input is an integer three-digit number in the range [111… 999]. I have used string instead of int, to quicker read and store all char values. The issue here is that when I have the char let's say '3' I need to use the int value of '3' and not the ASCII Dec value of 51. As I had a limited time to write this code I succeeded to resolve it by subtracting 48 as you can see in the code provided. What is the correct/more advanced way to do this exercise ? Thank you in advance!


Let $\mathbb R^+$ be the set of positive real numbers and let the natural numbers be $\mathbb{N} = \{ 1,2,3,\ldots \}$. Let $\star_x$ be an operator on $\mathbb{R}^+$ such that   \begin{align} a \star_0 b &= a + b \\ a \star_1 b &= a \cdot b \\ a \star_2 b &= a^b \end{align}  And so on. In particular, if $b\in \mathbb{N}$ and $x \in \mathbb{N}$, then $\star_x$ satisfies the recursive property  $$ y \star_x b = \underbrace{y \star_{x-1} y \star_{x-1} \cdots \star_{x-1} y}_{b \text{ times}} $$  Is there a natural way of extending $\star_x$ for any $x \in \mathbb{R}^+$ so that the map $(a,b) \mapsto a \star_x b$ is a continuous function of $x$? (EDIT: And, hopefully, a continuous function of $a$ and $b$?)


Rendered image doesn't show what Rendered Viewport shows... (pictures below)

It's kind of an interesting result.  Here is how render viewport should look on frame 1:    Here is what happens when I press F12:    It's like I have a second camera (although I don't) somewhere below. What is even weirder is that If I place the camera behind the wall...    it shows everything correctly (example cube is seen):    As you can see, my camera is following an object that is on Bezier curve WHILE being on Bezier curve (right) itself. This animation is working perfectly on rendered viewport but not if I use ctrl+F12. Just the same grey viewpoint.  What could be the issue?


Can you slow down pre-AD time progression in Civ V?

I find as I play the game that time passes too quickly early on. I did some research and haven't found anyway to modify this. Can it be done?


Is it okay, to put meshes inside each other without connecting them?

Excuse my English. So, im modeling an assault rifle and i was thinking about if its okay to disconnect the highlighted mesh(picture below) from the weapon and just move it a bit inside the weapon to achieve a lower polygon count and more clear mesh.   I want to export this model into Unreal(if this information is important)


How to add a TOC for each section and subsection before of each section in beamer?

At the beginning of each section I want to add a table of content without the subsections and a table of content with the subsections. What can I do?


Where are all the Stones of Barenziah located? (No Stone Unturned)

I can't seem to find a few of the Stones, so, is there a list available with the location of all the stones?


How tied are Linux installations to hardware?

If I install Linux on a USB stick using computer A, then plug it into computer B with different hardware and try to boot and work on it, should I generally expect it to work? Or should I rather accept that Linux, when installed (as opposed to using Live CD/USB), gets tied to the hardware and is generally not supposed to work seamlessly on different hardware?  If the answer is "it depends", let's narrow the question:   All hardware is x86. Nothing fancily customized, just stock laptops/desktops currently available on the market; Distros: latest OpenSUSE, Ubuntu or Cubes OS with default settings; No fancy software, just web/office etc.   The background behind this question is that I am deciding whether to have separate USB stick Linux installations for each computer I have, or just clone the same one.


How Did Obi-Wan (and Luke) Remain Hidden?

We know that Master Yoda remained on Dagobah to make use of the Living Force (and more importantly, the powerful Dark side energies) of the planet to help conceal himself during his self-imposed exile.  According to StarWars.com,  was:       a swamp-covered planet strong with the Force -- a forgotten world where the wizened Jedi Master could escape the notice of Imperial forces.   However, in all of the descriptions of Tatooine, I've never read anything that would seem to indicate that the desert planet afforded any such Force-masking qualities to its inhabitants.  If the Empire was, in fact, actively seeking Jedi for extermination, such powerful Force presences should have stood out on that planet like a beacon.  At the end of Episode III, Yoda tells Obi-Wan that he has further training for the young master.     Master Kenobi, wait a moment. In your solitude on Tatooine, training I have for you.   Which means that Obi-Wan would be actively tapping into the Force while on Tatooine, which, again, would suggest that he's basically sending up a flare to anyone looking.  Finally, Luke was able to sense Darth Vader's presence in the Sith Lord's Star Destroyer above the forest moon of Endor before they arrived.  It would seem to me that Vader may have been powerful enough to sense another Force user on the planet's surface while they were in orbit above Tatooine when capturing Princess Leia's "diplomatic" ship.  So, did Obi-Wan do or have some artifact or ability that actively dampened his (and Luke's) Force "radiance" from being noticed, or did the Empire simply ignore Tatooine as a possible haven for Jedi due to the Hutt control of the planet?


Move a range of numbered files and change their value

I've got numbered files (DSC_0001.jpg to DSC_0065.jpg) on a Linux machine, I know how to move them with mv DSC_{0001..0065}.jpg dir.  I have no idea how to move them and change the range of values.  mv DSC_{0001..0065}.jpg DSC_{0134..1198}.jpg is not working.  Is there another way to do this ?


What is $(1372)(56) \circ (154)$ and how to work out similar compositions?

What is $(1372)(56) \circ(154)$ and how to work out similar compositions?


Decide what class to use under runtime in C#

I wonder if it is possible to add a subclass in runtime while using C#.   I like to set a type on the main class and if possible having some code select the correct inheritance based on this information, is a thing like that possible to achieve?.  Here is a small example in the direction in what I like to do?.  Regards, Magnus   using System;  namespace ClassTest {      class Animal     {        public string type = "[Not set!]"; // use the correct class based on thi value.         public virtual string WhatDoesTheAnimalSay()        {           return "[no animal selected!]";        }     }     class Cat : Animal    {       public override string WhatDoesTheAnimalSay()       {          return "Meow!";       }    }     class Dog : Animal    {       public override string WhatDoesTheAnimalSay()       {          return "Woof!";       }    }     class Program    {       static void Main(string[] args)       {         // Cat cat = new Cat();         // Console.WriteLine("The Cat says: " + cat.WhatDoesTheAnimalSay());          // Dog dog = new Dog();         // Console.WriteLine("The Dog says: " + dog.WhatDoesTheAnimalSay());          Animal unknown = new Animal();         unknown.type = "Dog";         Console.WriteLine("The " + unknown.type + " says: " + unknown.WhatDoesTheAnimalSay());          Console.ReadKey();       }    } }


Did Harry ever visit the Dursleys in adulthood?

I was wondering whether Harry ever thought to visit the Dursleys after the war against Voldemort was won. He might have wanted to know how they were, how was their life while they were in hiding, etc.  According to an answer to , J.K. Rowling said that Harry would see Dudley, but I'd like to know if he ever saw his aunt and uncle again, especially after he saw Snape's memories in the pensieve and found out a bit more about her.


Shell test to find a pattern in a string

I just wanted to ask whether there is any command which would work on common shells (bash, dash, kornshell)? It is supposed to check if the line variable contains any part of the path.  if [[ $line =~ "$PWD"$ ]] ;then


Significance of assumption in competition inequality questions

Refer to the problem below (IMO 2009 Shortlist)     Let $a, b, c$ be positive real numbers such that $$\frac{1}{a} + \frac{1}{b} + \frac{1}{c} = a + b+ c$$   Prove that    $$\frac{1}{(2a+b+c)^2} + \frac{1}{(2a+b+c)^2} + \frac{1}{(2a+b+c)^2} \leqslant \frac{3}{16} $$    In the solution given by the  (Pg 16), it states that      Without loss of generality, we choose $$a +b+c = 1$$.    Thus, the problem becomes    $$ \frac{1}{(1 + a)^2} + \frac{1}{(1 + b)^2} +\frac{1}{(1 + b)^2} \leqslant \frac{3}{16}(\frac{1}{a} + \frac{1}{b} + \frac{1}{c})$$    Applying Jensen’s inequality to the function $$f(x) = \frac{x}{ (1+ x)^2}$$   ,which is concave for $0 ≤ x ≤ 2$   and increasing for $0 ≤ x ≤ 1$, we obtain   $$α \frac{a}{(1 + a)^2} + β \frac{b}{(1 + b)^2} + γ \frac{c}{(1 + c)^2} \leqslant (α + β + γ) \frac{A}{(1 + A)^2}$$   , where $A =\frac{αa + βb + γc}{α + β + γ}.$   Choosing $α = \frac{1}{a} , β =\frac{1}{b},$ and  $γ = \frac{1}{c}$   , we can apply the harmonic-arithmetic-mean inequality   $$A =\frac{3}{\frac{1}{a} + \frac{1}{b} + \frac{1}{c}} ≤ \frac{a + b + c }{3} = \frac{1}{3} < 1$$   Finally we prove:   $$ \frac{1}{(1 + a)^2} + \frac{1}{(1 + b)^2} +\frac{1}{(1 + b)^2} \leqslant ( \frac{1}{a} + \frac{1}{b} + \frac{1}{c}) \frac{A}{(1 + A)^2} \leqslant ( \frac{1}{a} + \frac{1}{b} + \frac{1}{c})\frac{A}{(1 + \frac{1}{3})^2} = \frac{3}{16}(\frac{1}{a} + \frac{1}{b} + \frac{1}{c}) $$   However,  (Pg 4) differs by having $a +b+c=3$ and setting $f(x) = \frac{1}{16x} - \frac{1}{(x+3)^2}$ and allowing Jensen to resolve the rest.   The questions are as follows;   How do you choose before hand which $a + b+ c =$ to choose?  Why particularly does the assumption differ between the 2 solutions? How does one know before hand the choosing of $α = \frac{1}{a} , β =\frac{1}{b},$ and  $γ = \frac{1}{c}$?  Where and how did $A =\frac{αa + βb + γc}{α + β + γ}$ come from?   Any help would be much appreciated.


I am migrating a Drupal 7 project from one PC to another and I did the following steps     1) Copy pasted the root folder into D:\XAMPP\htdocs    2)   Imported the database of that project into phpmyadmin (had to increase   max_file_uploads to 20 in php.ini)  3) reset admin password   by referring   4) updated the   password in settings.php  5) cleared cache in the imported db   (by deleting the content of cache and cache_* tables)   Now I am able to login but the admin panel is blank, When I click Dashboard, Content, Structure, Appearance etc. nothing appears  No error is console.  PS: this is the first time I am using Drupal, so in-depth instructions is much appreciated  Edit  After 's suggestion I had set display_errors to on and error_reporting to E_ALL. Still no error appears anywhere  Edit From watchdog the last two rows;  Second-Last row      uid : 1 Message : Session opened for %name. location :   http://localhost:81/mysite/user referer :   http://localhost:81/mysite/user   Last Row     uid : 0 Message : Attempting to re-run cron while it is already   running. location : http://localhost:81/mysite/users/admin   referer : http://localhost:81/mysite/user


Effective Sample Size for posterior inference from MCMC sampling

When obtaining MCMC samples to make inference on a particular parameter, what are good guides for the minimum number of effective samples that one should aim for?  And, does this advice change as the model becomes more or less complex?


Magnetic monopole and electromagnetic field quantization procedure

From the Maxwell's equations point of view, existence of magnetic monopole leads to unsuitability of the introduction of vector potential as $\vec B = \operatorname{rot}\vec A$. As a result, it was introducted by Dirac fiber-like theory of monopole, which is considers a model of monopole as the open end of a semi-infinite solenoid. This is physically unsatisfactory. Another approach, is the introduction of another 4-potential along with $A_{\mu},(\text{where  } \mu = 0,1,2,3)$. But such models had problems with formulating in a frame of the principle of least action. And if I'm not mistaken, this problem had been solved (see ). A two-potential models, seems to be more acceptable.   How will the quantization procedure of the electromagnetic field change in two-potential models? Does the photon acquire an additional degree of freedom?


Convert a video by setting the final size

Is there a way to set the maximum final size for video converting using ffmpeg (or any other CLI based video converter)?  Like if I have an 100mb video and want to convert it to a 10mb video with the highest quality possible, considering the final format isn't important.


If $\mid a_{jj}\mid \gt \sum_{i \neq j} \mid a_{ij} \mid$ then vectors $a_1,\dots ,a_n \in \mathbb{R}^n$ are linearly indendent.

Let $a_1,\dots ,a_n \in \mathbb{R}^n$ with $a_i = (a_{i1}, \dots , a_{in})$.  Show that when $\mid a_{jj}\mid \gt \sum_{i \neq j} \mid a_{ij} \mid \; \forall \; j\in \{1,\dots ,n\}$, then $a_1,\dots ,a_n$ are linearly independent.  I want to show that the matrix \begin{matrix} a_{11} & a_{21} & \cdots & a_{n1} \\ a_{12} & a_{22} & \cdots & a_{n2} \\ \vdots & & \ddots & \\ a_{1n} & a_{2n} & \cdots & a_{nn} \end{matrix} can be transformed into an upper triangular matrix with all entries in the main diagonal $\neq 0$.  For the cases $n=1$ and $n=2$ this is easy. However, I fail to show this for the general case; the problem being that the tranformations mess up the coefficients such that I can't use the assumption on the $a_{jj}$'s anymore.  I'm pretty sure that this has already been solved somewhere on here, but I don't know how to search for it.


How to update custom post meta via rest API

I am using python to send Post requests to /wp-json/wp/v2//. This successfully updates default info such as title, content etc. However I am unable to make any changes to the custom theme meta data structured like "post_meta":{     "meta_1":[],      .      .      "meta_n":[] }   Thanks


Power Supply : How to keep SMPS always above the post-regulator that follows it

I'm trying to find a way of building a new power supply for my workshop, in order to keep it small and not so hot I will be using a spare xformer to step down mains to 24v and then a variable buck converter to adjust it (and CC mode, displays and blinky stuff).   I thought it would be a good idea to use a linear regulator on the output stage to smooth things out, but I can't seem to think of a control scheme that allows me to change the voltage using only one potentiometer. The buck stage is this topology but with a external PNP transistor.(It has already been prototyped, it works alright, I know the mc34063A is old)   The only idea I got that ""works"" is using the buck converter output as a reference for a linear regulator (IC or discrete parts), but using a SMPS output as reference for anything is a bad idea, due to the amount of noise and fluctuations.   This is the sort of output stage I can and have built (or bought) over time. Just a big discrete regulator.  In short: How to control a MC34063A step down (buck) converter so it follows the output stage +1-3 V of headroom.


I have a Lenovo Thinkpad X1 yoga, which has an OLED display. This means the brightness isn't set in the usual way, but luckily you can get around that with scripts using xrandr --brightness. Specifically, I have a  set up that listens for brightness changes and then uses xrandr to implement them. Unfortunately, this does not take into account color temperature, and so does not pick up changes from Gnome Night Light. Where does Night Light store its current settings, and how does one get access to them? Or better yet, is there a way to convince Night Light to use xrandr to set brightness?  NB: This is not a duplicate of . OLED displays do not respond to the usual way of setting brightness. So Night Light by itself only changes the color temperature, but not the brightness. On the other hand, I can set the brightness with xrandr, but this overrides the color temperature. Can I get Night Light to use xrandr to set brightness instead of the standard method? Or, failing that, how do I read out Night Light's settings to set the correct temperature and brightness myself?


Have we directly observed the electric component to EM waves?

For example, has anyone has directly observed charges oscillating due to standing EM waves? I am particularly interested because it'd demonstrate that radiation has a transverse electric component to it. Anything else (historical or modern) that shows that light has a transverse electric component would also be gladly invited.


In TeX/LaTeX's default mode, there is extra space after sentence-ending periods, which needs to be suppressed with \@. when TeX would mistakenly treat it as ending a sentence, as in Mr\@. Bean. While \frenchspacing eliminates the (nominally) double space between sentences, I wonder if sentence-ending periods are nevertheless treated differently from abbreviation periods (e.g., when stretching spaces, computing penalties, or whatever).   In other words: If I use \frenchspacing (and will never format my text without it), is there any point to writing \@.?


I am a fairly strong user of ArcGIS, having started with version 8 long ago. But I'm looking for an inexpensive alternative right now for a client, and I want to investigate QGIS as a possible solution.  Thing is, I have never touched it before. I see mention of Grass databases and OSGEO4W shells and Python. I don't know what any of that means. No clue.  So where can I find a beginner's guide to QGIS, that more or less walks a newbie through the various components, how they work, why they're needed, and gets me to the point that I can import a .gdb and make some sample maps and queries to show my client?


Don't include SE site in SE search filter?

I couldn't find this question here, but I would like to be able to search all sites in the SE network except some sites. In my case, I want to remove the thousands of results from SO on a popular project for devs so I can see the handful of results on other sites from admins and users.  The current form only allows all sites or listed sites.  The answer linked does not tell me how to use the information in the answer. It is a poor answer for an average user.  As @Laurel describes in the comment below, the answer at  no longer works.


Will laptop Dell Inspiron 15 7000 gaming 7567 work with Ubuntu?

I am planning to buy a laptop that meets my requirements and is compatible with Linux,this one meets my desired requirements, but will it run Linux Ubuntu or no?  Dell Inspiron 7567 is said to be certificated, but I'm not sure if this applies to gaming edition, here is the laptop:


An interesting exponential integral problem

Suppose $a : [0 , 1] \to \Bbb R$ is an infinitely smooth function. For $\lambda\ge1$, define $$F(\lambda) := \lambda \int_0^1 e^{\lambda t} a(t) \, dt.$$ If $\sup_{\lambda\ge1}|F(\lambda)|\lt\infty$, then $a$ is the identically zero function.  My professor said this assertion is true but I haven't been able to solve this for some time. He also implied that this problem is highly non-trival (at least for me).  Below are the some results I have derived:   Derivatives of any order of $a$ vanishes at $t = 1.$ For any $\delta\lt1$, $a(t)$ has a zero in the open interval $(\delta , 1).$  The same is true for all the derivatives of $a(t)$. This tells us that the $n^\text{th}$ derivative of $a$ has infinitely many distinct zeros for all natural $n$. If $a$ is analytic, then I can show that $a(t)\equiv 0.$ If $a(t)\ge0$ on $[0 , 1]$, then it is obvious that $a\equiv 0.$   I would appreciate any hint.  Actually $(1)$ and $(3)$ follows from $(2)$. For $(2)$, suppose that $a(1)\gt0$ (the case that $a(1)\lt0$ can be argued in the same way as the following), then there exists $\delta\lt1$ such that $a(t)$ is strictly positive on $I = [1-\delta , 1]$. Then write $F(\lambda) = \lambda\int_0^{1-\delta}e^{\lambda t}a(t)dt + \lambda\int_{1-\delta}^1e^{\lambda t}a(t)dt$. Now there exists $c\gt0$ such that $a(t)>c$ on $I$ since $I$ is compact, so that the second term is bounded below by $c (e^{\lambda}-e^{\lambda(1-\delta)})$. But the first term is only $O(e^{\lambda(1-\delta)})$, so this contradicts the fact that $F(\lambda)$ is bounded. Morever, using the same idea and integration by parts, one can see that $n^{th}$ derivative of $a$ must vanish at $1$.


Poor Text Quality 1080P HD Monitor 12.04

My situation  I'm not proficient with Ubuntu or Linux. I'm a Windows convert. My computer tech knowledge is also novice. I'm running a NVIDIA GF119 on UBUNTU 12.04. Under Additional Drivers I have "NVIDIA accelerated graphics driver (post-release updates) (version 331-updates)" activated and currently in use.  I'm a student and I read hundreds of page of text out of ebooks everyday.  My issue  Text quality is blurry.  It's hard to tell the difference between i's and l's (infact I can't tell the difference as I just typed those two.)  also m's and n's often look the same.  I don't know what refresh rate I'm currently running, but my monitor is built to run 60 hz.  I tried xrandr -r 60 and got this.     Rate 60.0 Hz not available for this size   I found another article on this, but the solution was over my head.  How can I get the text readable?  Thank you!


Different appearance of the `sim' in \sim and \succsim

I have to write a LaTeX document using a particular style using the preamble below. When I use binary relation \sim, it looks very different (much flatter) than the corresponding part of \succsim.   How can I make the output of \sim look more like the corresponding tilde in \succsim?  MWE and its output below.  \documentclass{standalone} \usepackage{lmodern} \usepackage{fourier} \usepackage[T1]{fontenc} \usepackage[utf8]{inputenc} \usepackage[english]{babel} \usepackage{microtype} \usepackage{amssymb}  \begin{document} $\succsim \quad \sim$ \end{document}


I don't mean to start a[nother] civil war over this issue, but should nullification be enforced or not?  While trying to fix a bug (that was fixed elsewise, as can be seen ), I added code like this in a couple of places to immediately and explicitly set some objects to null:  List<String> XMLFiles = CCRUtils.GetXMLFiles(fileType, @"\"); foreach (string fullXMLFilePath in XMLFiles) {     RESTfulMethods.SendXMLFile(fullXMLFilePath, uri, 500); } XMLFiles = null;   Now that I know that did not solve the problem I was having, should I just leave it, or remove this type of code?


LyX: unable to display equation reference correctly with Latvian babel

I'm using Lyx and I want to have the reference format similar to This is the reference to equation 2.1  My LaTex file is %% LyX 2.2.3 created this file.  For more info, see http://www.lyx.org/. %% Do not edit unless you really know what you are doing. \documentclass{article} \usepackage[T1]{fontenc} \usepackage[latin4]{inputenc} \setcounter{secnumdepth}{5} \setcounter{tocdepth}{5} \setlength{\parskip}{\bigskipamount} \setlength{\parindent}{0pt} \usepackage{amsmath} \usepackage{amsthm}  \makeatletter %%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Textclass specific LaTeX commands. \numberwithin{equation}{section} \numberwithin{figure}{section}  \makeatother  \usepackage[latvian]{babel} \begin{document}  \section{Section}  This is a formula \begin{equation} y\left(x\right)=x^{2}\label{eq:foo} \end{equation} This is a cross-reference \ref{eq:foo} \end{document}  I've been trying different options, eg. changing the LaTex preamble, the document class, adding/removing modules like Number Equations by Section, etc. but nothing seems to work. What I can get is 2..1 => <Reference> on Page <Page> 2 => <Reference> (2) => (<Reference>)  What should I do to get my equations in <section>.<number> format? UPDATE The problem was caused by \usepackage[latvian]{babel}. Solution: .


Limit of ratios of numbers with $m$ factors and primes

This is my first question.   Let $a_1, a_2,\ldots, a_k$ be natural numbers $\leq n$ with $m$ prime factors.  Let $p_1, p_2, \ldots, p_r$ be the prime numbers $\leq n$.   Let $$C_{m,n} = \frac{\sum_{i=1}^{k}a_i}{\sum_{i=1}^{r}p_i}$$ Does the following limit exist when $m\geq 2$? Obviously, when $m=1$,  $C_{1,n}=1$.  $$\lim_{n\to \infty} C_{m,n}$$  I have some guesses but not defendable enough.  My best,  The FM.


I'm working with a long table in and I'm having some issues with the it. I can't wrap the text in the last column, which uses multicolumn. Therefore, the text goes out of margins. Here's my code:   \usepackage{multirow} \usepackage{makecell}  \begin{tabularx}{\textwidth}{XXXXXX}%[H]         \hline     Header that can be wrapped & Header 2 & Header 3 & Header 4 & Header 5 & Header 6\\        \hline     Data1 & 0.111 & 0.112 & 0.113 & 0.114 & \multirow{3}{*}{This text is too long and can not be wrapped}\\     Data2 & 0.221 & 0.222 & 0.223 & 0.224 & \\     Data3 & 0.331 & 0.332 & 0.333 & 0.334 & \\     \hline     \end{tabularx}     I've tried to force the line in the last column to break, but then it invades the cell below. This is what I've tried:    \usepackage{multirow}  \usepackage{makecell}     \begin{tabularx}{\textwidth}{XXXXXX}%[H]             \hline         Header that can be wrapped & Header 2 & Header 3 & Header 4 & Header 5 & Header 6\\            \hline         Data1 & 0.111 & 0.112 & 0.113 & 0.114 & \multirow{3}{*}{This text is too long and can not be wrapped}\\         Data2 & 0.221 & 0.222 & 0.223 & 0.224 & \\         Data3 & 0.331 & 0.332 & 0.333 & 0.334 & \\         \hline         Data4 & 0.111 & 0.112 & 0.113 & 0.114 & \multirow{2}{*}{Cell bellow}\\         Data5 & 0.221 & 0.222 & 0.223 & 0.224 & \\         \hline         \end{tabularx}     Any idea of how can I fix this situation?


Is there a word to encompass the two states of a day: AM and PM, morning and afternoon?

A single word which sums up the option of AM/PM or morning/afternoon.


I have this code, why bo3= st1 == st2  gives true ?   are not they in different position in the memory, and by == we compare the position whether  it is the same or not !  Also if there is something wrong, please indicate me. Thank you guys.  public static void main(String[] args) {      String st1 = "HELLO";     String st2 = "HELLO";     String st3 = "hello";       int comp1 = st1.compareTo(st2);  // equal 0     int comp2 = st1.compareTo(st3);  // -32      boolean bo1 = st1.equals(st2); //true     boolean bo2 = st1.equals(st3); // false , if ignoreCase will be true      boolean bo3 = st1==st2; //true    ??????????? should not be true     boolean bo4 = st1 == st3; //false       int ind1 = st1.indexOf("L"); // 2     int ind2 = st1.lastIndexOf("L"); // 3      boolean con = st1.contains("LLO"); //true       System.out.println(bo3); }   While I have another code when I enter "Mary", the result: Same name  and  not equal  public static void main(String [] args) {      Scanner keyboard = new Scanner(System.in);     System.out.print("What is your name? ");     String name = keyboard.next();      if (name.equals("Mary"))         System.out.print("Same name");     else         System.out.print("Different name");      if (name == "Mary")         System.out.println("equal");     else         System.out.println("not equal"); }


Being inspired by , I've wondered if the infinite series below may be expressed as an intregral. I'm very curious about that.   $$2\sum_{k=1}^{\infty}\frac{(2k-1)^2-1}{(2k-1)^4+(2k-1)^2+1}$$  I'd appreciate your feedback here. How should I ponder over this case as a simple student? Where should I start from and what techniques I need to think of? Thanks!


I followed this tutorial () for an expandable list view, in which I enter different shop names, categorized by the part of town they are located:   But there is obviously no need to have the same group several times (which is the case for Neukölln for example).  Here is what I tried to do:  SparseArray<Groups> groups = new SparseArray<Groups>(); DatabaseHandler db = new DatabaseHandler(this) ; List<Shop> shops = db.getAllShops();      Groups group = null ;     String str = "null" ;      int i = 0 ;     for (Shop shop : shops){         // if current shop's district differs from district of the shop of the last iteration         if ( shop.getDistrict() != str ) {             // making sure that empty group is not appended into groups in the first iteration             if (group != null) {                 groups.append(i, group);                 i++;             }             // saving the district of the current shop             str = shop.getDistrict();             // creating a new group named after the current district             group = new Groups(str);         }         // adding shop name to the current district         group.subitems.add(shop.getName()) ;     }     // after last iteration the last group needs to be appended to the groups     groups.append(i, group);   I hope you can understand the basic idea of my code. I sure it has to work out, because I went through it on paper and in theory it works. My first idea was that those if-statements are responsible, but I have no clue how to repair this.


Being that Tolkien was a Catholic, I wouldn't be surprised if he made Eru three different people, but I can't think of any references to it.  If so, who are the three persons?


Prove $\limsup\limits_{n \to \infty} (a_n+b_n) \le \limsup\limits_{n \to \infty} a_n + \limsup\limits_{n \to \infty} b_n$

I am stuck with the following problem.     Prove that $$\limsup_{n \to \infty} (a_n+b_n) \le \limsup_{n \to \infty} a_n + \limsup_{n \to \infty} b_n$$   I was thinking of using the triangle inequality saying $$|a_n + b_n| \le |a_n| + |b_n|$$ but the problem is not about absolute values of the sequence.  Intuitively it's clear that this is true because $a_n$ and $b_n$ can "reduce each others magnitude" if they have opposite signs, but I cannot express that algebraically...  Can someone help me out ?


Is it legal to look for work in the US while on a B1/B2 (Business Visitor) visa?

I have got 10-year multiple entry US VISA on my Indian passport. I got it to attend a technical conference.    I was curious to know if I give job interview during this visit? I may not have time in this visit, but what if I go after couple of months with $3000 of my saving to sustain for a month and look for job. Is this legal?    I know I need H1-B VISA to work there, but I feel it is easier to get job (even if sponsorship is needed) to be face2face with potential employers. So, is it legal to look for job with B1/B2 ? Can I mention that to immigration officer?  PS: Yes, I'm Software Developer :P


I am trying to get this script to function correctly but I get ./passmark.sh line 7: [y command not found.  Here is my script  #!/bin/bash # A simple script to ask a user for a pass mark and then display a grade # the grade will be either an A, B, C, D or F # CONT=y echo while [$CONT = "y" ] do         echo -e "\"Please enter a pass mark: \c \""         read MARK         if [$MARK -ge "0" -a $MARK -lt "50"] ; then                 echo -e "\n \"F\" \n"         elif [$MARK -ge "50" -a $MARK -lt "60"] ; then                 echo -e "\n \"D\" \n"         elif [$MARK -ge "60" -a $MARK -lt "70"] ; then                 echo -e "\n \"C\" \n"         elif [$MARK -ge "70" -a $MARK -lt "80"] ; then                 echo -e "\n \"B\" \n"         elif [$MARK -ge "80" -a $MARK -lt "100"] ; then                 echo -e "\n \"A\" \n"         else                 echo -e "\"Invalid input!!\n \""         fi         echo -e "\"Would you like to enter another pass mark? (y/n) \c \""         read REPLY         case "$REPLY" in                 n | N | no | No | NO ) CONT=n ;;                 *) ;;         esac echo done


Is the TCP protocol good enough for real-time multiplayer games?

Back in the day, TCP connections over dialup/ISDN/slow broadband resulted in choppy, laggy games because a single dropped packet resulted in a resync. That meant a lot of game developers had to implement their own reliability layer on top of UDP, or they used UDP for messages that could be dropped or received out of order, and used a parallel TCP connection for information that must be reliable.  Given the average user has faster network connections now, can a real time game such as an FPS give good performance over a TCP connection?


NullPointerException is thrown by main class while accessing static method from other class

I am trying to access the getrownum() from the main method, however NullPointerException is thrown.  Main class:  public class MainDriveScenario {      public static void main(String args[]) throws Exception {         ExcelUtils.setExcelFile(Constant.Path_TestData + Constant.File_TestCaseExecSheet, Constant.Sheet1_TestCaseExecSheet);          int rownum = ExcelUtils.getrownum(Constant.Sheet1_TestCaseExecSheet);          for (int i = 1; i < rownum + 1; i++) {             String exec = ExcelUtils.getCellData(i, 2);             System.out.println(exec);             String testcaseID = ExcelUtils.getCellData(i, 0);             System.out.println(testcaseID);          }     }  }   ExcelUtil class:   public class ExcelUtils {      public static void setExcelFile(String Path,String SheetName) throws Exception {              try {                  // Open the Excel file              FileInputStream ExcelFile = new FileInputStream(Path);              // Access the required test data sheet              ExcelWBook = new XSSFWorkbook(ExcelFile);              ExcelWSheet = ExcelWBook.getSheet(SheetName);              } catch (Exception e){                  throw (e);              }      }  public static int getrownum(String Sheetname) {             int rownum = ExcelWSheet.getLastRowNum();             return rownum;         }     }


how to add a custom lock for the recovery and/or bootloader?

Unlocking the bootloader and/or the recovery is very popular discussion across many devices. But doing so exposes a very obvious and inevitable issue with security!  An unlocked recovery means that no matter how secure you make your android lock screen, someone can easily reset phone to restore the phone to a fully functional (and lockless/insecure) state and the worst part, they don't have to erase your data(meaning they can access all your personal files and folders)!  It is almost hilarious! In fact if the phone supports insertion of external SD cards, you can even flash your own software into the phone and maybe bypass the lock screen without wiping any data.  For example: One possible loophole is using the 'Tasker' app which has a feature that can temporarily disable the keyguard. And the best part is that Tasker can be flashed using the recovery!  So is there any method by which I could add a security measure that prevents complete access to my recovery and/or boot loader that will make my phone less insecure?!  Expected answer: Method by which a custom pin/password must be entered before entering the bootloader/recovery. So that my bootloader/recovery is still technically unlocked but simply requires authentication to use (this also ensures that conventional unlocking methods won't work as the phone is not really locked!). This also means that one does not have to lose root access to ensure security!


How come the portkey at the maze didn't transport "at a prearranged time"?

In Harry Potter and The Goblet of Fire, when Mr. Weasley and Mr. Diggory are leading a group to the Quidditch World Cup, Mr. Weasly explains:     I believe there’s a handy wood they’re using as the Apparition point. For those who don’t want to Apparate, or can’t, we use Portkeys. They’re objects that are used to transport wizards from one spot to another at a prearranged time. You can do large groups at a time if you need to.   However, this happens at the end of Chapter 31, The Third Task:      “On three, right?” said Harry. “One — two — three —”He and Cedric both grasped a handle.Instantly, Harry felt a jerk somewhere behind his navel. His feet had left the ground. He could not unclench the hand holding the Triwizard Cup; it was pulling him onward in a howl of wind and swirling color, Cedric at his side.   So, how come the Triwizard Cup didn't transport the holder at a prearranged time, but at the first touch?  The canonical answer might be "you just put a charm so it will transport the first holder instantaneously", but if it was so easy/simple, many wizards would have done it to get to the World Cup before they were supposed to (or after! if they didn't want to wait for so many days...).


From thence vs. thence in the Apostles' Creed

In the Roman Catholic Church, the Apostles' Creed says, "From thence He shall come to judge the living and the dead." I am unsure whether "from thence" is correct or if it simply should be, "Thence He shall come to judge the living and the dead." This is based on a rudimentary understanding of the antiquated "thence" as being equivalent to modern "from there".


I once read that one way to obtain a unique filename in a shell for temp files was to use a double dollar sign ($$).   This does produce a number that varies from time to time... but if you call it repeatedly, it returns the same number.  (The solution is to just use the time.)  I am curious to know what $$ actually is, and why it would be suggested as a way to generate unique filenames.


How many $\alpha \in S_n$ are such that $\alpha^2 = 1$?

This is not for homework, but I am not great at counting arguments and would like some feedback.  The question asks     Let $n \in \mathbb{N}$. How many $\alpha \in S_n$ are there such that $\alpha^2 = 1$?   I know that, if $\alpha^2 = 1$, then either $\alpha = 1$ or $\alpha$ is the product of disjoint transpositions.  If $\alpha = (i, j)$ is a single transposition, then there are $\frac{1}{2^1 \cdot 1!} \binom{n}{2}$ such $\alpha$ (the $2^1$ and $1!$ are put in the denominator to help in noticing the pattern later).  If $\alpha = (i, j)(k, l)$ is the product of $2$ disjoint transpositions, then there are $\frac{1}{2^2 \cdot 2!} \binom{n}{2} \binom{n-2}{2}$ such $\alpha$, where the $2^2$ appears in the denominator to account for the cyclic permutations of each transposition, and the $2!$ appears to account for the permutation of the transpositions themselves.  If $\alpha$ is the product of $3$ disjoint transpositions, then there are $\frac{1}{2^3 \cdot 3!} \binom{n}{2} \binom{n-2}{2} \binom{n-4}{2}$ such $\alpha$.  Extrapolating from this, I find that the total number of $\alpha \in S_n$ such that $\alpha^2 = 1$ is $$ 1 + \sum_{i=1}^{\lfloor \frac{n}{2} \rfloor} \frac{1}{2^i \cdot i!} \prod_{k=0}^{i-1} \binom{n-2k}{2}. $$  Does this look OK?  It looks like a rather ugly answer to me, so I have my doubts.  Any input would be welcomed.


Is there a way to revoke an edit approval?

It has happened that I've been too quick at approving a suggested edit and realized only upon later review that it had flaws. Is there a way, in this case, to revoke the approval?


What's the general equation of a curve after a rotation about the origin?  Specifically, what's the equation (either piecewise or implicit) of the unit parabola after a counterclockwise $45^{\circ}$ rotation?    I feel the generalised rotation matrix should be all I need but I can't figure out where to go from here :(


Which are the standard commands available in every Linux based distribution?

I would like to know which are the standard commands available in every Linux system.  For example if you get a debian/ubuntu/redhat/suse/arch/slackware etc, you will always find there commands like:  cd, mkdir, ls, echo, grep, sed, awk, ping etc.  I know that some of the mentioned commands are shell-builtin but others are not but they are still always there (based on my knowledge and experience so far).   On the other hand commands like gawk, parted, traceroute and other quite famous commands are not installed by default in different Linux distributions.  I made different web searches but I haven't found a straight forward answer to this.  The purpose is that I would like to create a shell script and it should make some sanity checks if the commands used in the script are available in the system. If not, it should prompt the user to install the needed binaries.


Check if exists function $f(x,y):R^2->R$ such that f(x,y) has directional derivatives in point (0,0) in each direction and (0,0) is point of discontinuity.


How do I test for a named item in a players inventory? (Minecraft 1.13)

So I'm trying to make a command that tests for a named item in a players inventory, and executes if they have that item. I know that you can test for an item type, but how do I make it test for a name too? Please bear in mind: I am trying to figure this out for Minecraft 1.13, not any previous versions.  *Edit: I have already tried this command with no success:   execute at @a[nbt={Inventory:[{id:"minecraft:blaze_rod",Count:1b,tag:{display:{Name:"{\"text\":\"Doomstick\"}"}}}]}] run say hi  Edit 2: So after some testing I think it has to do with the attribute modifiers or text color I'm using with the name. Any ideas?


Who is the most powerful user of the Force?

I just saw a  where Starkiller vaporized an entire platoon of stormtroopers with a single energy blast or something.  What are the effective limits on the Force and who is its most powerful user within both the accepted canon and Legends?


What is the difference between "get my hair cut" or "have my hair cut"

I have my hair cut.   I get my hair cut.      What is the difference between the two sentences in meaning?


I want the inner while loop to be broken when the input data is 5, but if the input is other than 5, the loop will be executed again. In this code, the input value of each number I enter is printed as X = 1: x = 1 while True:     def state():         x = input("Enter Your number:")      while True:         print(x)         if x==5:             print('x=5')             break         state()   In this code, I tried to solve the problem but it didn't work too. condition = True x = 1 while True:     def state():         x = input("Enter Your number:")      while condition:         print(x)         if x==5:             print('x=5')             condition = False         state()   Is there anyone to help me?


What was Voldemort doing during the events of Half Blood Prince?

From the first chapter of The Half-Blood Prince (The Other Minister) the following things are known:   The Ministry finally realized that Voldemort was back. (End of The Order of the Phoenix)    Death Eaters were out in the open wreaking havoc on the Muggle and wizarding world .(Most probably on Voldemort's orders, in order for Voldemort to blackmail Fudge to give him access to the Ministry). Voldemort needed Dumbledore out of the way and had enlisted Draco for the job. Killing Amelia Bones (and maybe killing a few more people).   Apart from this, for the rest of the duration of the book, there is hardly any information about what Voldemort did for an entire year.  I know the book narration is from Harry's point of view but I am curious to know if there is any canon or any other interview/text by JKR where any details of Voldemort's activity during Harry's sixth year has been given?


Let $F$ be a field. Let $F[x]$ be the polynomial ring and $f(x)$ and $g(x)$ be 2 irreducible polynomials of same degree in $F[x]$. When do we have the 2 fields $$F[x]/<f(x)> \cong F[x]/<g(x)>$$   Well, I can think of $F[x]/<f(x)>$ as the field $F(\alpha)$ where $\alpha$ is the root of $f(x)$ and check if any algebraic combination of $\alpha$ with elements of $F$ is a root of $g(x)$. If it is then both the fields are the same/isomorphic. But is there any general condition on the 2 polynomials such that the isomorphism holds?


I am assuming that $\lambda\neq0$ and $B$ is an $n \times n$ matrix such that $$B^3-2B^2-6B+\lambda I_n=O_{n,n}$$ Show that $B$ is invertible.  I know  that for B to be invertible then $\det(B)\neq0$. But I do not know where to go from here.


Blinking purple screen New installation Ubuntu 20.04

I have an old acer pc and I wanted to install ubuntu 20.04 after trying, so I did the installationi ticked normal installation update and graphic something then I installed in a hard drive everything went well when i restarted it demanded my password but when I hit enter blinking purple screen appear mouse doesnt work keyboard either Help me I am stuck  Graphic card geforce 9200  CPU: amd athlon II X3 435  Thanks for your time  Edit: product: Aspire X3400     *-display  graphics card:                        nVidia C77 [GeForce 8200]  Primary display adapter: #12  Edit2:the problem is partially solved now ican boot to ubuntu but only on VGA I did that by using 'sudo apt-get purge nvidia*' but now i dont have a driver for my card  lspci | grep VGA 02:00.0 VGA compatible controller: NVIDIA Corporation C77 [GeForce 8200] (rev a2)  (I have a 9200 ) how to correct this problem?


Prove consecutive Fibonacci numbers are coprime

I'm working on a proof that $$\gcd(Fn, Fn-1) = 1$$ for all n greater than or equal to 0. Here's what I have so far. I used a proof by induction. I used $$\gcd(1,0) = 1 $$ for the base case. For the inductive step I assumed $$\gcd(F_n, F_{n-1}) = 1$$ and set up $$\gcd(F_{n+1}, F_n)$$ $$ = \gcd(F_n, F_{n+1} \bmod Fn)$$ $$ = \gcd(F_n, (F_n + F_{n-1]) \bmod Fn)$$ I'm a bit confused about what to do at this step. Do I use $$\gcd(a+b, b) = \gcd(a,b)$$? If so, how do I prove that? Would appreciate some help!


Graphic glitches, icons and text disappears with Thinkpad T450 and Ubuntu 14.10 Gnome

I bought Lenovo ThinkPad T450 with hope that it would work straight out of the box, most ThinkPads have really great support early on imo. But this laptop isn't really coping with me.   The problem I have is when I switch workspaces or something, the icons and text disapears and I can't see any, I have to hover my mouse over the different objects to see them. Switching workspaces back and forth works. I use I3 window manager but the problem is the same with Gnome 3.   Lets get down with some specs:  00:00.0 Host bridge: Intel Corporation Broadwell-U Host Bridge -OPI (rev 09) 00:02.0 VGA compatible controller: Intel Corporation Broadwell-U Integrated Graphics (rev 09) 00:03.0 Audio device: Intel Corporation Broadwell-U Audio Controller (rev 09) 00:14.0 USB controller: Intel Corporation Wildcat Point-LP USB xHCI Controller (rev 03) 00:16.0 Communication controller: Intel Corporation Wildcat Point-LP MEI Controller #1 (rev 03) 00:19.0 Ethernet controller: Intel Corporation Ethernet Connection (3) I218-LM (rev 03) 00:1b.0 Audio device: Intel Corporation Wildcat Point-LP High Definition Audio Controller (rev 03) 00:1c.0 PCI bridge: Intel Corporation Wildcat Point-LP PCI Express Root Port #6 (rev e3) 00:1c.1 PCI bridge: Intel Corporation Wildcat Point-LP PCI Express Root Port #3 (rev e3) 00:1d.0 USB controller: Intel Corporation Wildcat Point-LP USB EHCI Controller (rev 03) 00:1f.0 ISA bridge: Intel Corporation Wildcat Point-LP LPC Controller (rev 03) 00:1f.2 SATA controller: Intel Corporation Wildcat Point-LP SATA Controller [AHCI Mode] (rev 03) 00:1f.3 SMBus: Intel Corporation Wildcat Point-LP SMBus Controller (rev 03) 00:1f.6 Signal processing controller: Intel Corporation Wildcat Point-LP Thermal Management Controller (rev 03) 02:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. RTS5227 PCI Express Card Reader (rev 01) 03:00.0 Network controller: Intel Corporation Wireless 7265 (rev 59)   Thanks for any help.


How to form an interrogative possessive sentence?

A. Do you have a car?   Or     B. Have you a car?   I always use the first form of the sentence but I noticed that the second one is also used. Which is correct?


"need + verb-ing" vs "need + [to be] + verb-ed"

1 That sofa needs cleaning again. 2 That sofa needs to be cleaned again.  Which of the above senteces sounds more natural? And, is "to be" always needed in structures like 2, as, for example, in:  2/a You need your head examined. 2/b You need your head to be examined.


If you shine a flashlight pointing outwards inside a black hole, would the photon go down to the singularity? Is there any way to visualize the path of a photon going to the singularity, or would that path be irrelevant because the singularity is in all directions?


Slow Trigger performance when big batches

I have an update trigger that inserts into auditing tables.  We had no problem until someone decides to update over 1 million records... (That's my bad. I didn't think it would be a problem when developing). Now facing reality, I need to find a solution...  I've been doing many tests and researches to try to figure out how to solve my issue of having a trigger perform poorly...  I've come to the conclusion that to minimize the bad performance of the "Table Insert" in the execution plan, I need to insert in smaller batches.   The question is:  Since I'm not sure of where all the different updates can come from, I'm trying to figure out how I can insert the auditing records in batches within the trigger?   example, The update of the main table for 1 million records would happen and call the trigger, which would insert 100 thousand records at a time in some type of loop.  Is this possible? If so, how do you suggest? If not, how else can I improve the table insert of the execution plan?   Addition of test scripts to reproduce:   This is a simplified version of the real thing   -- drop trigger PriceHist_trig_U  -- drop table MyPriceTable -- drop table price_history Create Table MyPriceTable (SKU varchar(13), PriceGroup varchar(5), PriceLevel int, Price float, Qty float, ManyOtherColumns Varchar(100) CONSTRAINT [PRICE_TAB_P01] PRIMARY KEY CLUSTERED  (     SKU ASC,     PriceGroup ASC,     PriceLevel ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY]  Declare @Id int Set @Id = 1  While @Id <= 1000000 Begin     insert into MyPriceTable values (right('000000000000' + CAST(@Id as nvarchar(10)),13),'Grp ' + CAST(@Id%10 as nvarchar(10)), @id%3, RAND()*(25-10)+10, 1, 'there are many other columns')    Print @Id    Set @Id = @Id + 1 End  -- Drop table   price_history  create table price_history (SKU varchar(13), PriceGroup varchar(5), PriceLevel int, Price float, Qty float, ManyOtherColumns Varchar(100), historyDate datetime, ChangedColumns varchar(Max)) CREATE NONCLUSTERED INDEX price_history_nc1 ON price_history (     HistoryDate ASC,     SKU ASC,     PriceGroup ASC,     PriceLevel ASC )  go Create TRIGGER PriceHist_trig_U ON MyPriceTable FOR UPDATE  AS  INSERT INTO price_history (SKU, PriceGroup, PriceLevel, price, Qty, ManyOtherColumns, HistoryDate, ChangedColumns)              SELECT INS.SKU,INS.PriceGroup,INS.PriceLevel,INS.Price,INS.Qty,INS.ManyOtherColumns, getdate(),   CASE WHEN update(Price) and INS.Price<>DEL.Price THEN 'Price-' ELSE '' END + CASE WHEN update(Qty) and INS.Qty<>DEL.Qty THEN 'Qty-' ELSE '' END + CASE WHEN update(ManyOtherColumns) and INS.ManyOtherColumns<>DEL.ManyOtherColumns THEN 'other-' ELSE '' END  FROM INSERTED INS  JOIN DELETED DEL ON DEL.sku=INS.sku AND DEL.PriceGroup=INS.PriceGroup AND DEL.PriceLevel=INS.PriceLevel  WHERE  (update(Price) and INS.Price<>DEL.Price)      OR (update(Qty) and INS.Qty<>DEL.Qty)      OR (update(ManyOtherColumns) and INS.ManyOtherColumns<>DEL.ManyOtherColumns)  /* tests */  update MyPriceTable set price = price-1   When I run this with the trigger disabled, it runs in 2 seconds. When the Trigger is enabled, it took 32 seconds to complete. The Execution Plan shows 98% on the "Table Insert"   I've been trying to figure out how to improve the table insert, but can't find anything concrete...   I've tried with a Clustered index and the performance is worse.  Any help would be appreciated


Is an ampersand (&) in a company name not ideal for Google or SEO?

I am working on a site with a company name with an & in it. An alternative is using and instead of &.  Does & have some disadvantages in a company name we have to know of? Does it effect SEO? Can Google 'work' with it?  Are there some other disadvantages?   Update  The domain name is not a problem, because there is used and. It's not a problem to use and, but in the logo is & used. So on site they want to use & also.  But i think people are going to search for the and version. It's easier to type C and A instead of C&A (certainly in my case). But when i'm using & on the site everywhere Google might not discover we mean the same. Or is that a crazy though?


Well,    meters measures distances or lengthes, volt measures tension or voltage, , kelvin measures temperature, second measures time, ampere measures electric current, kilogram measures mass,   But what measures the "Byte" unit ? I'm looking for a word that would take the same place than mass takes for kilogram, but for Byte (or bit, as 8 bit makes a Byte.). There's only very unspecific terms that springs to my mind (size, capacity, ...):   My file is 3.2 KB in <fill the blank> ? My hard drive has a <fill the blank> of 2TB. Byte measures <fill the blank>.   Could it be information ? But the word alone doesn't seem to refer to something that can be measured. And you don't use it as naturally. For example, in a technical specification you could see:   mass: 3kg temperature: 2° voltage: 3V <fill the blank>: 3TB   But what would you use here in front of "3TB" for instance ? It seems we must use 2 words, for example:  "information size". But even this doesn't seem so natural.  Have you any word suggestions that I've might missed, references on this topic, if not, do you know other units that don't have a proper word to name what they measures ?  Edit: I'm a software developer and I know relatively well what a Byte measures. I'm looking for a specific English word that could be used as naturally as you would use the word "mass" to qualify what you measure when you say "3 kilograms".


In movie Pirates of Caribbean: Salazar's Revenge, lead actor is trying to remove all of the curses of the sea so he can remove the old curse of The Flying Dutchman and eventually release his father William Turner from a curse. and in the end he got success doing that but one thing I don't understand is how William Turner is alive without his heart  As per curse, The Flying Dutchman must have a captain and whoever kills the captain be the next captain by giving his or her heart to the ship.  So, how did William Turner survive natural death after curse has been released?


Copying 100 files at a time using terminal

Is there an option to copy first 100 files from a directory to another location using the cp command? If not is there any other way to do this? Do i need to write a script?


When should you consider indexing your sql tables?

How many records should there be before I consider indexing my sql tables?


Who planted the bomb under the stage in Bodyguard?

Who placed the bomb under the stage that killed Julia Montague?


Is there a Windows program to edit photo time stamp in batch like in Google Photos?

I have 3000 photos taken this year (2017) on a camera which had the date & time set incorrectly so all these photos are stamped with a 2015 date.  I would like to change the time stamp on all of these photos. I am going to upload them to Google Photos eventually.  I know I can do this very easily on Google Photos but the problem is that there are other existing photos on the account and my 3000 photos will mix in with them so when I would want to change their date, I would have to go and hand-select one by one. And AFAIK there is no way to tell the Google Photo uploader to sync the photos into an album.  I guess an option would be to create the album on Google Photos via web and upload directly into the album but the upload will take forever and I am pretty sure I'd lose control over it (network issues, PC issues, etc).  So I thought I would do the change before uploading them. Is there any windows tool (command line will do) to - basically set the start date of the batch and the tool would move all the time stamps accordingly?


Does scikit-learn have forward selection/stepwise regression algorithm?

I'm working on the problem with too many features and training my models takes way too long. I implemented forward selection algorithm to choose features.  However, I was wondering does scikit-learn have forward selection/stepwise regression algorithm?


Where is the password stored for ssh authentication?

It's known that when you're connecting to a wrong server via ssh and send your password  to it, your password comes in a plain text and a server saves it by default. Probably. I wonder, where I can retrieve it? I don't see it in /var/log/auth.log, although I do see all the attempts to authenticate.


How to solve this equation if $x\in \mathbb{R}$, $x ^3+1 =2\sqrt [ 3 ]{ 2x-1 }$, find $x$

If $x\in \mathbb{R}$, and $$x ^3+1 =2\sqrt [ 3 ]{ 2x-1 }$$ find $x$.   I asked my teacher to help me in solving it, he responded I can't! So, I hope you help me in solving it or even giving me hints that will help me in solving.


Closed site is not being removed from app favorite sites list

Recently I was in the private beta for Game Theory, however it didn't take off and the site was closed down. When the site was closed, it was automatically removed my from my favorites in the drop down menu on the desktop version. The android app however did not remove it from the favorites and now is reporting it as an unknown site. It seems like the site should have been removed from the desktop and android versions at the same time.  When I went in to edit the pinned sites on my android app they did not appear and were gone when I canceled. So the app will correct itself but you must go in to attempt to edit first.


Prove $\gcd(k, l) = d \Rightarrow \gcd(2^k - 1, 2^l - 1) = 2^d - 1$

This is a problem for a graduate level discrete math class that I'm hoping to take next year (as a senior undergrad). The problem is as stated in the title:     Given that $\gcd(k, l) = d$, prove that $\gcd(2^k - 1, 2^l - 1) = 2^d  - 1$.   The problem also says "hint: use Euclid's lemma," although I'm not sure what part of the problem should be applied to. I've been thinking about it for a few days and I'm completely stumped.   I'm not really even sure how to show that it divides either $2^k - 1$ or $2^l - 1$. From the given, we know that $\exists c: dc = k$. We need to show that $\exists c': (2^d - 1)c' = 2^k - 1$. Obviously $c' = 2^c$ gives you $(2^d - 1)c' = 2^k - 2^c$, but I can't figure out how to get rid of the extra terms that the $- 1$ brings in in various places.  From Euclid's lemma on the left side, you know $\exists i: di = k - l$, and applying it on the right side, you know it suffices to show that $\gcd(2^k - 2^l, 2^l - 1) = 2^d - 1$. And by Bezout's identity, it's enough to show that $2^d - 1$ can be written as a linear combination of either of those things.  Can anyone give me a hint?


Retrieve website source code from Windows 7

Is there a way to retrieve the source code of every webpage in a website and save them to a single text file?  With the appropriate CRFL characters just as if the pages were retrieved individually under Internet Explorer?  I've tried Wget, but can't seem to find the right combination of options.


How to register a popover panel that doesn't show anywhere else in the UI

I'm using layout.popover(my_panel) to draw a panel in a box when it is clicked on, but I don't want that panel to be visible anywhere else in the UI. Just removing the bl_category setting from the panel class simply puts it in a category named "misc". I realise that one solution could be to change the bl_region_type to something different, but if I change it to something like "TEMPORARY" it just gives me an error. Is there a correct way to do this, or would it be better to do it from say the invoke method of an operator?


Proving an inequality by induction, how to figure out intermediate inductive steps?

I'm working on proving the following statement using induction:  $$ \sum_{r=1}^n \frac{1}{r^2} \le \frac{2n}{n+1} $$  Fair enough. I'll start with the basis step:  Basis Step: (n=1) $$ \sum_{r=1}^n \frac{1}{r^2} \le \frac{2n}{n+1} $$ $$ \frac{1}{1^2} \le \frac{2}{1+1} $$ $$ 1 \le 1  \checkmark  $$  Inductive Step: $$ \sum_{r=1}^{n+1} \frac{1}{r^2} \le \frac{2(n+1)}{(n+1)+1} $$ $$ \sum_{r=1}^{n+1} \frac{1}{r^2} \le \frac{2(n+1)}{n+2} $$  My goal is to prove $\forall_{n\ge1} s(n) \implies s(n+1) $ or that this inequality holds true for all $n\ge1$.  I'm not quite sure to go from here on the inductive step. I understand that I need to basically work some clever substitution and manipulation into the problem to end up with: $$ \sum_{r=1}^{n+1} \frac{1}{r^2} \le \frac{2n}{n+1} $$  However, I'm not quite sure what needs to done to obtain this after attempting a few times.


I noticed a particularly nice math font being used in this paper: .   Does someone recognize it? I've tried detexify but could not find it.  Here is an A:    a B:    and a U:


Is the following series converging or diverging. $\sum_{n=1}^{\infty}\dfrac{n+4^n}{n+6^n}$

I know one solution.   That is by Doing comparison with $\dfrac{4^n+4^n}{6^n}$  Wondering if there are more ways to do it


As in the title. If $x,y>0$ and $x^2+y^3\ge x^3+y^4$, prove that $$x^3+y^3 \le 2.$$  This seems to be a very tricky one. I tried applying various inequalities like AM-GM, unfortunately, none of techniques I'm familiar with seem to work here.  I'd greatly appreciate any hints.


How to figure out a creature's weaknesses?

I was wondering what you and other players would do when coming across a new monster in a campaign. You obviously want to try to figure out what weaknesses this creature has, what it's resistant to, etc.  Is it more usual to ask 'out of character', or is it more common to roll some kind of in-game check to identify the creature?


I'm not that old, but when I was a child/teen, stadia was the common term.  As in:        Wembley, the Nou Camp, and the Santiago Bernabeu are football stadia.   The MCG and Lord's are cricket stadia.      But now stadiums is the more common term. Is this shift essentially redundant? I've read some sources say that it better reflects English language pluralisation, but then I think "so what?" Stadia better reflects the Latin root, and English isn't a wholly logical/systematic language (very few languages are). If we call more than one dog dogs, more than one ox oxen, and use cattle both as singular and plural, then why does it matter?


Prove that $x^2<\sin x \tan x$ as $x \to 0$

$$x^2<\sin x \tan x \quad as \; x \to 0$$  I made the substitution $x \to \arctan x$ .   $\arctan^2 x<x\sin (\arctan x)$  $\arctan x < \large \frac{x}{(x^2+1)^{\frac 14}}$  There are two functions $f(x)$ and $g(x)$ . $f(0)=g(0)$ . If $f'(x)>g'(x)$ on the interval $(0, a)$ , then that implies that $f(x)>g(x)$ on the interval $(0, a)$ . Therefore if $RHS'>LHS'$ , then $RHS>LHS$ .   $LHS'=\large \large \large \frac {1}{x^2+1} <RHS'=\frac {x^2+2}{2(x^2+1)^{\frac 54}}$  $\large \large \large \frac {1}{x^2+1}<\frac {x^2+2}{2(x^2+1)^{\frac 54}}$  $1<\large \frac {x^2+2}{2(x^2+1)^{\frac 14}}$   Using standard techniques (such as first derivative test) we can show that the $RHS$ has a minimum at $(0, 1)$ so we have proved the inequality.  I have two questions:   $1)$ Is my proof correct?   $2)$ Are there nicer ways of doing this inequality (without involving math higher than calc 1)? I have tried AM-GM and others but I think it is very hard to do it very elegantly because the $RHS$ is such a good approximation of the $LHS$ as $x \to 0$ .


Update KB4088849 is not applicable to the equipment, Windows Server 2016

I've been trying to install the update KB4088889 and the update KB4089510 on Windows Server 2016, but the equipement show message that say: The update is not applicable in this equipement.  I have verified that: the problem occurs with all updates.  I have problems to execute windows updates through independent windows installers.


32.768 kHz crystal for RTC, should the case be soldered to GND?

I've seen this on a few boards, but I don't know if it's the right thing to do. Should the case be soldered to GND?  It is the common cylindrical :


I have applied for a UK visa twice and i got a rejection the first time was in 2013 and the rejection reason was the bank statment and that i was outsourced for Pfizer and provided an HR letter mentioning that i am worki g as a contractor for Pfizer however i mentioned in the application that i work for Pfizer . The second time i applied i got a rejection and the reason was that i said in the application i worked for pfizer as a headcount "permenant " resource sine july 2016 however when he searched for a history he found my old application that is mentioning april 2013 . I amattaching a copy from the rejction letter , and i need an advice on what to be done to get the visa as i am afraid to apply for the third time and get a rejection .


Integrate $ \int \frac{x^2 + x}{(e^x + x +1)^2}dx $

$$ \int \frac{x^2 + x}{(e^x + x +1)^2}dx $$   I cant think of any substitution to start this question.


does one have to keep stock until the dividend payment date to get the dividend? (Record Date vs Payment Date)

For example:  has a dividend record date 3/30/2015 and a payment date of 5/13/2015. When one sells the stock now, past record date, but before payment date, will one still get the dividend?


What to do when you find copied SF, SU or SO content on other websites?

Recently, while answering a Server Fault question, I stumbled upon a copied Server Fault question and answer at what looks like a content aggregation or text scraping site.    Here's the original thread:  Here's the copied site: http://www.answerspice.com/c118/1787456/spf-include-too-many-ip-addresses   To be fair, the "copied" site gives attribution to all of its scraped content. However, this brought up an interesting topic in my mind which led to three questions:   Is there even an offense if a site scrapes trilogy content or are we all just one big GPL family? If this is an offense, does attribution (such as what AnswerSpice does) lessen the offense in cases like this?  What is the proper thing to do if a site is found to be scraping content from one of the trilogy sites in a way that is not allowed?


stringstream parser;  parser << 5; short top = 0; parser >> top; parser.str(""); //HERE I'M RESETTING parser  parser << 6; //DOESN'T PUT 6 INTO parser short bottom = 0; parser >> bottom;   Why doesn't it work?


I'm looking for a book/pdf/guide to quantitative finance that contains all of the necessary mathematical prerequisites, as well as modern quantitative finance topics. Preferably something written at the advanced undergraduate/beginning graduate level.   Any recommendations are greatly appreciated. I cannot seem to find a comprehensive text that is written in a reasonably rigorous way (makes use of theorems from lin alg, probability, analysis, etc).   Thanks!