Load record information in lightning component

I wrote a simple lightning component to launch from a quick action on a detail page from the SF1 iOS mobile app. This will launch a deep link to a 3rd party app. The mobile URL is stored in a field on the object that launches the quick action. When pulling in the URL field, it keeps saying the attribute inspection is undefined. I wanted to know if I am pulling in the fields correctly using the force:recordData component. The component and controller are below: Component: <aura:component implements="flexipage:availableForRecordHome,force:lightningQuickActionWithoutHeader, force:hasRecordId">       <aura:attribute name="inspection" type="Object" />     <force:recordData aura:id="recordLoader"     recordId="{!v.recordId}"     fields="Id, Mobile_URL__c"     targetFields="{!v.inspection}"     />       <aura:handler name="init" value="{!this}" action="{!c.doInit}" />   </aura:component>  Controller: ({     doInit: function (component, event, helper) {           var urlEvent = $A.get("e.force:navigateToURL");         urlEvent.setParams({             "url": "{!v.inspection.Mobile_URL__c}"         });         urlEvent.fire();           setTimeout($A.getCallback(function () {             var dismissActionPanel = $A.get("e.force:closeQuickAction");             dismissActionPanel.fire();         }), 5);     } })


Fantasy 3 or 4 book series, where the protagonist's best friend is a fat guy called ‘Marat' or ‘Marad'

I read this a few years ago, I think it was written in the '90s or later. The style is Terry Goodkind's Sword of Truth (well, to me). The name of the author might be similar, too.  The story revolves around the prince of a medieval-type kingdom, one of over ten in an area of fragile peace. The people (of all the kingdoms) are waiting for a warrior(?) to reveal himself as some sort of 'Chosen One' with a special name. There are hints that the protagonist might be him, but it later seems he does not have one of the foretold requisites (something to do with his birth?). At the end of the first book, after a huge battle, the prince's father dies but the prince loses his kingdom because the majority of the warlords saw his battlefield behaviour (incorrectly) as unbecoming.  The second book tells of how the prince, in the company of a small band of followers, including his wine-loving friend, Marat (or Marad) travels looking for that ‘leader’ or something.  I only got partway through the second book but am curious to read the rest. Could someone identify the series for me, please?


I've looked all over Stack-Overflow and Google for a simple REGEX for MySQL that satisfies the following requirements:   Finds all rows with a Non English Characters (ö, etc) Match any part of the column not just the first or last Allowed characters are anything but foreign characters (acceptable: _, A-Z, 0-9, # , " ' ( ) - @)   Any suggestions?


!st ed: The Summon Monster and Summon Nature's ally spells all have a casting time of 1 round.  My regular group have always taken that to mean that the summoned creature begins to act in the following round.  My new group (I'm GM for the first time) is claiming that it should appear and start to act in the round in which the spell is cast.  Who is right?  Does it make any difference if the caster is actually a Preservationist Alchemist invoking Bottled Ally?


I have the following query, the alias it's called DELAY, works fine, but when I try to run the first query adding AND DELAY < 0, the alias is not recognized.  I tried to create the alias QUERY AS DELAY or QUERY AS "DELAY" but no success.  The strange thing is that the alias DELAY in the order by doesn't generate errors.   SELECT ITK_TCK_ID,                     ITK_OPENED_DATE,                     TO_NUMBER(ROUND(ROUND(GET_HS(ITK_OPENED_DATE,                                                  SYSDATE,                                                  ITK_NORMAL_BEGIN,                                                  ITK_NORMAL_END,                                                  ITK_WEEKEND_BEGIN,                                                  ITK_WEEKEND_END,                                                  ITK_FREEDAY_BEGIN,                                                  ITK_FREEDAY_END),                                           GET_HS(ITK_OPENED_DATE,                                                  SYSDATE,                                                  ITK_NORMAL_BEGIN,                                                  ITK_NORMAL_END,                                                  ITK_WEEKEND_BEGIN,                                                  ITK_WEEKEND_END,                                                  ITK_FREEDAY_BEGIN,                                                  ITK_FREEDAY_END)) -                                     ITK_EXPIRATION_TIME,                                     2)) DELAY                FROM INSTANTIATED_TICKLERS               WHERE ITK_AR_SBP_ID = 'PEAJU_PP' -- P_WGR_ID               AND DELAY < 0               ORDER BY DELAY DESC;   Any suggestions?


Is it possible to use DateTimePicker (Winforms) to pick both date and time (in the dropdown)? How do you change the custom display of the picked value? Also, is it possible to enable the user to type the date/time manually?


May we write $\sqrt{x^2}=\pm x$.        Is  $\sqrt{x^2}=\sqrt{(\pm x)^2}=\pm{x}$ true ?  But we write $\sqrt{x^2}=|x|=x$  What is the actual logic?


Can I upgrade from 14 LTS to 15 without formatting ubuntu 14.  I currently have Win 7 and 14 LTS as dual boot. I don't want to mess things up cuz of the grub menu.


Show that if $X_1, X_2,...,X_{11}$ are random variables, and $\operatorname{corr}(X_i,X_j) = r$ for $ i\neq j$ , then show $r \geq -1/10$

$\DeclareMathOperator{\corr}{\mathsf{corr}}$Show that if $X_1, X_2,...,X_{11}$ are random variables, and $\corr(X_i,X_j) = r, i\neq j$ , then show $r \geq -1/10$. I think I need to do this with induction for $n$, so if $X_1, X_2,...,X_{n}$ are random variables, and $\corr(X_i,X_j) = r$ for $i\neq j$ , then  $r \geq -1/(n-1)$. I got the first step, when $n = 2$ it's saying if $X_1,X_2$ are random variables, then $\corr(X_1,X_2)\geq -1$, which is true because $|\operatorname{cov}(X_1,X_2)| = |E[(X_1 - E(X_1))(X_2 -E(X_2))]| \leq  D(X_1)D(X_2)$, where $D$ is the variance, so $|\corr(X_1,X_2)| \leq 1 \implies \corr(X_1,X_2)\geq -1$. I can't go any further when I assume it's true for $n-1$.


Why is my regular font garbled but \emph and \textbf fine?

I'm trying to format a document following my organization's style guide. I'm using XeLaTeX for the font flexibility. I made a minimal document \documentclass{article}     \usepackage{xltxtra} %% For XeTeX font commands \setmainfont[Ligatures=TeX]{Frutiger LT Std 45 Light} \usepackage[includeheadfoot, margin = 0.5in]{geometry}  \begin{document} Main font, no styling, \emph{with emphasis}, \textbf{and bolded}. \end{document}  and the \emph{} and \textbf{} text comes out just fine, but the rest is garbled:  The part where it's probably my fault I needed to use this font in some graphs generated in R. I have several fonts in the Frutiger family installed on my (Windows) machine, and they're OTF fonts. To get the font to work in R, I need to use the extrafont package, which only works with TTF fonts. So I fed Frutiger LT Std 45 Light into an online OTF to TTF converter, and reinstalled the TTF version. It works great for my R figures, but maybe that has something to do with my XeTeX font problems. If I run the above example with \setmainfont{Frutiger LT Std 55 Roman} instead of using the TTF-converted light face, nothing is garbled, it's just too heavy. My compilation report for the example above says 0 Errors, 0 Warnings; the .log file reports ................................................. . fontspec info: "defining-font" .  . Font family 'FrutigerLTStd45Light(0)' created for font 'Frutiger LT Std 45 . Light' with options []. .  . This font family consists of the following shapes: .  . * 'normal' with NFSS spec.: . <->"Frutiger LT Std 45 Light/ICU:script=latn;language=DFLT;" .  . * 'bold' with NFSS spec.: . <->"Frutiger LT Std 45 Light/B/ICU:script=latn;language=DFLT;" .  . * 'italic' with NFSS spec.: . <->"Frutiger LT Std 45 Light/I/ICU:script=latn;language=DFLT;" .  . * 'bold italic' with NFSS spec.: . <->"Frutiger LT Std 45 Light/BI/ICU:script=latn;language=DFLT;" .................................................  Any help/pointers?


US VWP interruption and return from Canada

Sorry about my wrong terminology, thank you for the corrections, I am revising my question a little so hope it is a little clearer. Thank once again.  We plan to travel to the US (Colorado) from the UK in early February 2018 under the VWP. Our return flight to the UK is scheduled for mid-June 2018. We plan to purchase an RV and then spend 60 days in the Western US then travel overland into Canada for approximately 40 days (asking US immigration to log us out when we leave). We understand our 90-day allowance will continue to 'run down' whilst we are in Canada. Our questions are:   Will our initial 90-day allowance expire when we are 'logged out' by US immigration. If not, does it matter? If our entry into the US expires whilst we are in Canada, is there any process for a UK citizen to apply for some sort of visa that would guarantee entry into the US for another 25 days or so? After spending approximately 40 days in Canada (therefore 100 days after we originally entered the US), will we be able to simply apply for re-entry into the US at an overland crossing from Canada (and will the initial VWP entry in February have any bearing)? We will then spend approximately 25 more days in the US, heading back to Colorado to sell the RV and fly back to UK around mid June 2018.   While I understand that the B2 visa option would solve this issue, getting that process completed (timescale, interview in London, etc) makes it impractical for us in this case.


Express $\forall n \in \mathbb N$, $\exists m \in \mathbb N$, $n^4 = m^2$ in words without using the symbol $\mathbb N$.   My Solution:  For all $n$ that is an element of Natural number there is $m$ that is also an element of natural number such that $n^4 = m^2.$  Can I have a feed back on my solution or explanation on how to do the problem.


I want to write text like this, where the word circumference should come under the word When.


Create PyString from c character array without copying

I have a large buffer of strings (basically 12GB) from a C app.  I would like to create PyString objects in C for an embedded Python interpreter without copying the strings. Is this possible?


Option clash when using graphicx and tikz packages

The following code fails Option clash for package graphicx, it seems to be an incompatibility between the package graphicx (when the option pdftex is used) and the package tikz.  \documentclass[a4paper,10pt]{book} \usepackage[T1]{fontenc} \usepackage[utf8x]{inputenc} \usepackage{tikz} \usepackage[pdftex]{graphicx}  \begin{document}      The lazy dog...  \end{document}   I am currently working with Debian wheezy (updated as of 10th November 2012), and the latest TeXLive LaTeX distribution included.  Any ideas?


I know the inverse limit of $k[x]/(x^n)$ is $k[[x]]$ but i can't show the homomorphism between these is onto.   For example $\alpha:k[[X]]\to\varprojlim k[x]/(x^n)$ by F(x)=family of$ F(x)+(x^n)$. for example $(1+(x),0,5+7x^2+(x^3),3+11x+132x^2+(x^4),0,...)$ is image of things in k[[x]]?


The Sylow theorems say that all $p$-Sylow subgroups are conjugate.   Is that the only thing they are conjugate to? In other words could a $p$-Sylow subgroup also be conjugate to something that is not a $p$-Sylow group?   Or does the fact that every element with order dividing $p$ is in a $p$-Sylow group mean that that is never possible?


How to code "if (#3 is not empty) then (do something) endif" in LaTeX?

EDIT: Answer found here:   Consider the following code snippet from a .sty file  \makeatletter \newcommand{\Snippet}[3]{%      \@namedef{csh#1}{\sremA{#2}{#3}}%     \@namedef{bea#1}{\sremB{#2}{#3}}% }%  \newcommand{\sremB}[2]{     \begin{frame}     \frametitle{#1}     \begin{shadedrem}         #2     \end{shadedrem}      \end{frame} }   I want to change this code to   \makeatletter \newcommand{\Snippet}[4]{%      \@namedef{csh#1}{\sremA{#2}{#3}}%     \@namedef{bea#1}{\sremB{#2}{#3}{#4}}% }%  \newcommand{\sremB}[3]{     \begin{frame}     \frametitle{#1}     \begin{shadedrem}         #2     \end{shadedrem}      \end{frame} %%% Pseudo code  if #3 is not empty then ( here I will process text in #3 ) endif }   I have the following questions. How to code the "if #3 is not empty then"?, and is it possible to create a command where the last argument is optional? Such that  \cmd{#1} \cmd{#1}{#2}   both work?


How can I express $\int \frac{1}{f'(x)}$ in terms of $f(x)$

More specifically, I would like to know if there is a way I can express  $$\int \frac{x g'(x)}{f'(x)} dx $$  In terms of $f(x)$ and $g(x)$. Both $f(x)$ and $g(x)$ are non-negative and known to be increasing in $x$. If that helps.


targeting first letters in an array for capitalization

function makeTitle(str) { let arr = str.split(' ');    for(let i=0; i<arr.length; i++) {     arr[i][0] = arr[i][0].toUpperCase();   }   return arr; }  makeTitle("This is a title")    //➞ "This Is A Title"  Hey guys, why isn't this changing the first letter of every word in the array? When I console.log it, I can see it selects 'T' 'i' 'a' and 't' like its supposed to. So why doesn't it change their values?


Do you know any way to generate doc and docx files with PHP and without COM component? I've tried PHPWord, which creates docx files, but these cannot be opened in OpenOffice because they cause it to crash. I've also tried PHPDocx, but it didn't generate any files at all.


Solving complex numbers equation $z^3 = \overline{z} $

We have the following equation:  $$z^3 = \overline{z} $$  I set z to be $z = a + ib$ and since I know that $ \overline{z} = a - ib$. I was trying to solve it by opening the left side of the equation.  $$ z^3 = (a+ib)^3 \Rightarrow $$ $$ [a^2+b^2+i(ab + ba)](a+ib) \Rightarrow $$ $$ a^3 - b^2a - 2b^2a + i (2a^2b + b^2a - b^3) $$  but this is where I got so far and I'm not sure how continue and if my solution so far is even the right way to solve it.


limit of a function which is defined for rational and irrational points on real line explicitly

$$ \text{Let }f(x)=x ,x\in \mathbb{Q}\\ \text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ } \text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }\text{ }=2-x , x \in \mathbb{R}-\mathbb{Q}$$ show that (i) $\lim_{x\to1}f(x) =1$  , (ii)$\lim_{x\to c}f(x) \text {does not exist, if }c\neq 1$


How to keep clean geometry, when beveling boolean cutouts

I want to model this gun:  So I started to cut out the rough shapes from a cube (using the boolean modifier) Then I tried to clean up the geometry to be able to round the edges of the handguard.  But it does not work. When I try to bevel it like in the last pic top right it just gets really messy.  I think I took the wrong approach. How would you go about adding clean and workable geometry to such a piece and would you use the Bevel tool to create the round shapes?


I am new to LaTeX and using it for my thesis. However, right now I am having trouble in using latexdiff. I did the instructions as follows: Question: How to generate latexdiff on Windows? Answer:  Download and install ActivePerl? Assume you install ActivePerl? in C:\Perl  Download latexdiff perl script Assume you download latexdiff to C:\temp  The latexdiff script makes use of the Perl package Algorithm::Diff Unzip Algorithm-Diff-1?.1902.tar.gz, and then copy whole Algorithm-Diff-1?.1902\lib\Algorithm directory to C:\perl\lib  Assume you have a old LaTeX file name old.tex and a new LaTeX file named new.tex both located in C:\temp  Start a new command prompt, type cd c:\temp to change the current directory to c:\temp. Type perl latexdiff old.tex new.tex > diff.tex, this will generate a new LaTeX file named diff.tex that contains the different between old.tex and new.tex   However, every time I typed c:\temp\perl latexdiff old.tex new.tex > diff.tex, the system says "perl is not an internal or external file", every time I typed c:\temp\latexdiff old.tex new.tex > diff.tex, it says "The perl interpreter could not be found." I have already checked the PATH variable, and it contains path to perl in c:\perl64\bin. What should I do next? I have exhausted every method but could not find a way.


Creating shapefile showing footprints of Rasters?

I have around 1,000 satellite images in tiff format, and I want to create a shapefile which will serve as an index to the rasters. This is something similar to a raster catalog, but I do not want to build a raster catalog.  Some obstacles I can forsee, is that the image are georefrenced, so they are not rectangular in shape (I am talking about the data area).  To clarify, I require the polygon to cover only the non-zero (or non nodata) pixels of the raster, and not the entire rectangular raster. Most of the answers so far, give a rectangular polygon, which covers the data, as well as the non-data pixels.  My Image     Result given by  tools I have examined (like raster catlog, various Arcscripts, custom Python script given in one of the answers):     Result that I want:


How to write methods that should only be used within the class itself and are able to access ivars

I have a class which has some methods that are only to be used within the class itself. These methods exist because I have a three-step process for the graphics work I'm doing, but I only want instances of the class to access the final result of those calculations, in a simplified example:  #import <Foundation/Foundation.h>  @interface GraphicsWorld : NSObject  @property(nonatomic, strong) NSMutableArray *objects; @property(nonatomic, strong) NSMutableArray *adjustedObjects  /* three methods I'll never use outside of this class   I want to find a way to get replace these methods.  */ -(void) calcTranslation; -(void) calcRotation; -(void) calcPerspective;  /* the one method I'll use outside of this class */ -(NSMutableArray *) getAdjustedObjects;  @end   I could define c-functions just outside of my implementation for this, but then they wouldn't have access to the properties:  #import <Foundation/Foundation.h> #import "GraphicsWorld.h"  void calcTranslation() {     // I'm useless because I can't access _objects. }  void calcRotation() {     // Hey, me too. }  void calcPerspective() {     // Wow, we have a lot in common. }  @implementation GraphicsWorld  -(NSMutableArray *) getAdjustedObjects {     calcTranslation();     calcRotation();     calcPerspective();      return adjustedObjects; }  @end


I want to redirect both stdout and stderr of a process to a single file. How do I do that in Bash?


I am using Mac OS terminal (similar to Linux) and trying to find best way to search inside all files on a computer that has extension *.py  What is the best way to achieve this?  I wanted to put 1 keyword for search and quickly show the whole path of these python files are that contain requested keyword in them..


I was playing Texas Holdem last night with some friends at my house and this was the hand we were dealt:  My cards 7♠ 6♦  His cards 10♠ 7♥  Cards on table  6♠ 8♠ Q♠ J♠ 2♠  Odd hand. Everyone else folded after the flop. Who would have won?  My arguments, 1. Because there is a flush on the table our pocket cards are void and we split the pot. 2. Because the Queen is the highest ♠ card on the table it is shared by both of us so we split the pot. I thought that in a flush the only card that matters is the highest for example if he had a pocket K♠ he would have won.   His argument, was that since his 10♠ is higher then my 7♠ he won and takes it all.  We were all confused and the vote between players was split 50/50 so i said house rules and split the pot. He got pissed and left the table and didn't come back. Was i in the wrong? Any help is appreciated.


i need help with this theoretical exercise with Riemann integration, hope you can help me. Thanks.  Prove that if $f:\mathbb{R}\rightarrow\mathbb{R}$ is continuous  $\vert f\vert$ Riemann integrable on $\mathbb{R}$ and  $$\int_{-\infty}^{+\infty}\int_{-\infty}^{+\infty} \frac{\vert f(x)-f(y) \vert}{\vert x-y\vert ^2} dxdy < +\infty$$  $f$ turns out to be constant.


I just had a confusion. Does the mass of the body actually increase when it is moving with a certain velocity? Or does it only look like the mass has increase to another observer. How can the actual mass of the body increase. Please correct me if I am wrong but I feel that it only seems to the observer that the mass has increased but it does not increase in real.  The increase of actual mass would imply that that its velocity will decrease to comply with conservation of momentum. But how can the velocity decrease if no external force is applied?


the rapper, stars in  as one of the main characters. However, his name is under "and" in the opening credits. Why is that? Is it because he is also a rapper? I am curious to know.


I've been reading the Wikipedia article on CSP () and one of the first formulas there has double vertical bars in it.  $$ {{w}}={\arg \max }_{{\mathbf  {w}}}{\frac  {\left\|{\mathbf  {wX}}_{1}\right\|^{2}}{\left\|{\mathbf  {wX}}_{2}\right\|^{2}}}$$ The text right before the formula says both the enumerator and denominator are variances of two multivariate signals. What do double vertical bars here mean? I know that double bars should mean the norm of a vector. In this case we have matrices (X1 and X2), so how can that be the norm of a matrix? Please help.


Have the same issue as  and   However the group vboxusers in the guest OS does not exist. I'm using VirtualBox 5.0.14 with guest additions and Extension pack installed. Have they changed the group name?  The groups that do exist in the guest OS are the following:  karl adm cdrom sudo dip plugdev lpadmin sambashare vboxsf   Also, I can't seem to add a Add Filter From Device as no devices are shown in the host OS:


Why is my total reputation less than my monthly reputation?

When I went to the  to see my ranking in the reputation league, I saw this. Is this an error? My total reputation is less than my monthly reputation.


Can't boot to Windows 10 after installing alongside Ubuntu 16.04 and using bcedit

I have Ubuntu 16.04 installed and I wanted to install Windows 10. I installed it and it skipped the GRUB and went straight to Windows 10. I used a copy of boot-repair USB disk and tried to run recommended settings but I  got this message:     GPT detected. Please create a BIOS-Boot partition (>1MB, unformattedfilesystem, bios_grub flag).   This can be performed via tools such as Gparted. Then try again.   After an hour of so of trying things I finally managed to boot into Ubuntu running this:  bcdedit /set {bootmgr} path \EFI\ubuntu\shimx64.efi   But now I can't boot to Windows, can't run boot-repair in recommended settings, in advanced settings tried settings sda1 (where the UEFI partition is) but grub2 isn't detecting my Windows. Also, I have an entry for an old Windows that's incorrect.   generated from boot-repair.  Here's the output of efibootmgr -v if it helps somehow:  BootCurrent: 0000Timeout: 2 seconds BootOrder: 0000,0002,0001,2001,2002,2003 Boot0000* Windows Boot Manager HD(1,GPT,fae7a125-e7c6-4570-9978-536f1ab52ece,0x800,0x100000)/File(\EFI\ubuntu\grubx64.efi)WINDOWS.........x...B .C.D.O.B.J.E.C.T.=.{.9.d.e.a.8.6.2.c.-.5.c.d.d.-.4.e.7.0.-.a.c.c.1.-.f.3.2.b.3.4.4.d.4.7.9.5.}...3................ Boot0001* Ubuntu PciRoot(0x0)/Pci(0x1f,0x2)/Sata(0,0,0)/HD(1,GPT,fae7a125-e7c6-4570-9978-536f1ab52ece,0x800,0x100000)/File(\EFI\ubuntu\grubx64.efi)A01 .. Boot0002* Windows Boot Manager HD(1,GPT,fae7a125-e7c6-4570-9978-536f1ab52ece,0x800,0x100000)/File(\EFI\Microsoft\Boot\bootmgfw.efi)RC Boot0003* Unknown Device: HD(1,GPT,fae7a125-e7c6-4570-9978-536f1ab52ece,0x800,0x100000)/File(\EFI\ubuntu\shimx64.efi)RC Boot0004* Unknown Device: HD(1,GPT,fae7a125-e7c6-4570-9978-536f1ab52ece,0x800,0x100000)/File(\EFI\ubuntu\shimx64.efi)RC Boot0005* TOSHIBA MQ01ABD100 BBS(PCMCIA,TOSHIBA MQ01ABD100 ,0x500)................-.f.......f.A.f...................................| .........A......................... Boot0006* Unknown Device: HD(2,GPT,5fca3638-90aa-4118-8d5a-09ed4f4191fa,0x12c800,0x96000)/File(\EFI\ubuntu\shimx64.efi)RC Boot0007* Unknown Device: HD(2,GPT,5fca3638-90aa-4118-8d5a-09ed4f4191fa,0x12c800,0x96000)/File(\EFI\ubuntu\shimx64.efi)RC Boot0008* Unknown Device: HD(2,GPT,5fca3638-90aa-4118-8d5a-09ed4f4191fa,0x12c800,0x96000)/File(\EFI\ubuntu\shimx64.efi)RC Boot000A* Unknown Device: HD(2,GPT,5fca3638-90aa-4118-8d5a-09ed4f4191fa,0x12c800,0x96000)/File(\EFI\ubuntu\shimx64.efi)RC Boot2001* EFI USB Device RC Boot2002* EFI DVD/CDROM RC Boot2003* EFI Network RC


Why is the "axiom of extension" an axiom?

I think this is a definition of = because it explains the meaning of the new symbol =. However, I wonder why the set theory thinks this as an axiom rather than a definition.


Understanding capacitor usage in the Sparkfun arduino

In the schematic for the Sparkfun Arduino mini pro 3.3v  there's a 0.1uF capacitor (C3) just left of the atmega ground pins going from vcc to gnd.  In the upper left corner on the power regulator there's also a 0.1uF (C10) cap from the output vcc to gnd which should be essentially the same thing.  What is the design rationale here?  I assume they're doing this for power smoothing but why not have a 0.2uF cap or two parallel 0.1uF caps on the regulator output?  Are they trying to say that the other one should be closer to the atmega?


Embedded fonts not showing up correctly in PDF generated using pdfpages in pdfLaTeX

I am using the pdfpages package to include some other PDF documents into a LaTeX document I'm processing with pdfLaTeX.  One of the included PDFs has some uncommon fonts.  They are embedded in the original PDF, and show up fine when looking at the document in Acrobat (Reader or full).  However in the final processed document, certain glyphs do not show up in Acrobat.  pdffonts shows that all of the fonts used in the original PDF are also embedded in the final PDF from the processed LaTeX. The problem is occurring with both TeX Live 2007 on a Fedora 16 box and MikTeX 2.9 on Windows 7.    Any idea what's going on here?


If $f_k \to f$ a.e. and the $L^p$ norms converge, then $f_k \to f$ in $L^p$

Let $1\leq p < \infty$. Suppose that    $\{f_k\} \subset L^p$ (the domain here does not necessarily have to be finite),  $f_k \to f$ almost everywhere, and  $\|f_k\|_{L^p} \to \|f\|_{L^p}$.    Why is it the case that $$\|f_k - f\|_{L^p} \to 0?$$   A statement in the other direction (i.e. $\|f_k - f\|_{L^p} \to 0 \Rightarrow \|f_k\|_{L^p} \to \|f\|_{L^p}$ ) follows pretty easily and is the one that I've seen most of the time. I'm not how to show the result above though.


I've got a table with data and to edit its fields I use this function  var tabM =  $('table#trips_info');  $('tr',tabM).dblclick(function(){             var tr_HL = $(this);              tr_HL.addClass('highLight_edit');             $('td',tr_HL).each(function(){                $(this).attr('contenteditable','true');             });              var sibls = tr_HL.siblings('tr');             $('html, '+ sibls +'' ).on('click',function(){                console.log(tr_HL.text());                 tr_HL.removeClass('highLight_edit');             });              event.stopPropagation();         });   especially this part is used to quit editing the current, but I cant make it work properly   $('html, '+ sibls +'' ).on('click',function(){                    console.log(tr_HL.text());                     tr_HL.removeClass('highLight_edit');                 });   I want the function to quit editing when user clicks NOT THE current tr but siblings tr or outside the tr an table area   Thx in advance


How do I turn the weather cycle off all the time?

What is the command to completely disable the weather in minecraft? I currently use /weather cycle 1000000 but it only works for a couple minutes. After that it resumes raining. I need the command to ensure it is permanently disabled for this world until I use a different command to make it resume. Thank you!


How to make a firstload function reload again on button Click (jQuery or JavaScript)

I am using a external theme but I have little knowledge of JS / jQuery. It uses this function to show images on hover:  $(document).ready(function() {       ....     FirstLoad();     .... });  function FirstLoad() {     ....      $('.showcase-list li a').on('mouseenter', function() {         $('#showcase-gallery').addClass('visible');         $('.showcase-list li a').addClass('disable');         $(this).removeClass('disable');          var aux = $(this).data('aux'),         preview = $('.showcase-img[data-aux="' + aux + '"]');            $('#showcase-gallery').find('.showcase-img').removeClass('active');         preview.addClass('active');     }).on('mouseleave', function() {         $('.showcase-list li a').removeClass('disable');         $('#showcase-gallery').removeClass('visible');         $('.showcase-img').removeClass('active');        });      .... }// End First Load   But I trying to paginate this gallery with Inifite Scroll JS which is going well except that function does not work on the newly paginated content. I suspect its because it does not load.   I have this code:  var $showcasegallery = $('#showcase-gallery').infiniteScroll({     path: '.gallery_next',     append: '.ajax-case-images' ,     loadOnScroll: false,     status: '.page-load-status',   });  var $showcaselist = $('.wrapper-case-links').infiniteScroll({     path: '.gallery_next',     append: '.ajax-case-links' ,     loadOnScroll: false,     status: '.page-load-status',   });   // load next page  var $viewMoreButton = $('.view-more-button'); $viewMoreButton.on( 'click', function() {   $showcaselist.infiniteScroll('loadNextPage'); $showcasegallery.infiniteScroll('loadNextPage');  });   This is working fine, but how can I make sure that other function reloads too on button click so that I can use this zoom function from the theme?


Is Python/ArcPy capable of delimiting strings with commas into different fields, and running a calculation based on those separate columns

Using ArcGIS ArcMap 10.6: I have a text field in an attribute table that has comma separated values (example: 12,24, 64, 87,29). For this example, I will name this field VALUES. Please note that VALUES includes data collected from field work so the spacing between commas will be varied. My current workflow is as followed:  Export the ID and VALUES fields in the attribute table into a .csv file using Table to Table in ArcMap 10.6 Open the .csv in Excel and run the 'text to columns' function under the Data ribbon Separate the VALUES field into multiple columns based on commas Run the calculation: Copy Column I values and ID columns into a new .csv file Save and close the new .csv file and join the shapefile to the new .csv file based on ID Export the newly joined shapefile into a new file and delete the duplicate ID field in the new shapefile  I am wondering if there is a way to automate this Python/ArcPy so I can create a custom script tool to do this without leaving the ArcGIS environment. Is there a way to separate values in a text field based on commas into different columns, run the above calculation, and have the values from that calculation entered in a new field named VALUES_CALCULATED?


Can't decide who to award the bounty to, they're all worthy

on the premise that it "wasn't getting any attention" and now it has gotten a bunch of helpful answers which all help me in some ways making it impossible for me to decide which one to award the bounty to.  Shouldn't there be an option to award the bounty equally among selected answerers, especially in this case where was getting no answers whatsoever before the bounty, or am I overthinking it and should award it to the first answer?


My question is why don't enter into if when acc.getUsername equals "stringExample"? When I print acc.getUsername() this line ealier it shows its equals but dont go into if, why?  @RequestMapping(value = "/login", method = RequestMethod.POST)     public ModelAndView checker(@ModelAttribute(value="acc") Account acc) {          System.out.println(acc.getUsername());         if(acc.getUsername() == "stringExample"){             System.out.println("aaa");         }          ModelAndView model2 = new ModelAndView("index.jsp");         return model2;     }


Lightning component not available in app builder

I have created a lightning component shell that I want to make available to the lightning app builder so I can drop the component into a new lightning app that I created. When I got to app manager and under select items I do not see the lightning component. When I created the lightning bundle, I added all the elements of the bundle, cmp, controller, helper, renderer, svg, design. Here is my component shell:  <aura:component implements="flexipage:availableForAllPageTypes" access="global">  </aura:component>   My domain is enabled. What else is needed in order to make the component available to select from the app builder?  Nothing  has been added to the component yet. It's just a shell at the moment.


I'd really like to learn how to play pen-and-paper RPGs.  I know that it takes a few players to actually sit down and play, but I'm not at all sure where to find more gamers.  How do I find existing groups to join? Or, are there any resources online that may help me find existing RPG groups or players?


What stories are connected to Lord of the Rings and The Hobbit?

Every time that I see a question here about Lord of the Rings, people talk about different ages and an extensive knowledge of characters that had no place in the story of the Lord of the Rings. Most of this information seems to be related to a time long before the events of Lord of the Rings took place.  Where is all of this coming from? What are all of the stories that connect to The Lord of the Rings?


Is it possible to set up a wildcard domain like "*-test.example.com"?  The main reason I'm asking is because I'm in the process of setting up Continuous Integration with Jenkins, and we'd like to automate the setting up of QA sites to test out specific branches of the codebase.  Say user A is working on a feature in a branch called 'awesome-feature-one', and user B is working on 'boring-code-cleanup'.   What I'd like to have is the DNS setup with something like '*-test.example.com' so that we have domains like 'awesome-feature-one-test.example.com' and 'boring-code-cleanup-test.example.com' without having to set up a DNS record for each and every one.  This way, we don't have to bug our network admin each time we start working on a new feature, it's already set up and we just have to make sure our web server is set up to point them to the proper place -- ie, 'awesome-feature-one-test.example.com' points to the folder /var/www/awesome-feature-one, etc, etc.  Lastly, part of the reason is that these sites use SSL, but our SSL cert is only set up to do wildcard for "*.example.com", so in order to set up wildcard for "*.test.example.com" we'd have to get another SSL cert ( which I may float as a solution if "*-test.example.com" won't work for DNS ).  So, is this possible, or am I looking at a pipe dream?


How to display only the negative contour labels?

How can I hide the positive contour labels covering the green area and only display the negative contour labels over the ocean areas? I am using QGIS 2.18.2. The contour file is a separate layer and when I enable labels I cannot hide the positive contours. Refer to the image below.


Proving that given any two points in a connected manifold, there exists a diffeomorphism taking one to the other

Suppose $M$ be a connected manifold and $x, y \in M$ are two points. Then I'm trying to show that there is a diffeomeorphism $f$ of $M$ that takes $x$ to $y$.  Since the set of points for which there is a diffeomorphism of $M$ taking $x$ to that point is clopen and $M$ is connected, I think it should be enough to consider the case when both $x$ and $y$ lie in the same chart. But how do I proceed from here? I think I should somehow take a vector field and consider flows, but I'm not really sure.   Can someone please provide a solution? Thanks in advance.


Find $f(2a-x)$ from the given equation $f(x-y)=f(x)\cdot f(y)-f(a-x)\cdot f(a+y)$ and $f(0)=1$

I have been trying to solve an exercise based on the relations and functions. Right now I had stuck to a question based on functions. The question says:  A real valued function $f(x)$ satisfies the functional equation $$f(x-y)=f(x)\cdot f(y)-f(a-x)\cdot f(a+y)$$ where $a$ is given constant and also $f(0)=1$. Then $f(2a-x) =$?  So far I know in these kind of questions we have to replace a specific variable with another value (maybe any constant or another variable). Like I had done an example previously. Here is an example:  Question says, $f(x)+2f(1-x)=x^2$, Then what is $f(x)$?   Answer: Given, $$f(x)+2f(1-x)=x^2\text.\tag1\label1$$ Replace $x$ with $1-x$. So now equation is $$f(1-x)+2f(x)=(1-x)^2\text.\tag2\label2$$ So after multiplying equation \eqref{2} with $2$ and subtracting equation \eqref{1} we can get the $f(x)$.  I know This one is quite easier than that I had asked because my question would need much more substitutions.


Why is the calculated volume wrong for extruded objects?

I have just noticed that when calculating a volume using the 3D-Print add-on I get completely different results when I extrude away material. In the picture you will find two cuboids of identical dimensions. The left one has been scaled to those dimensions. The right one has had material extruded away. The calculated volume of the latter is off by quite a bit. Same problem with calc_volume(). To provide a little detail: I added a plane, extruded it into the cube and selected 'DIFFERENCE'.  What is causing the calculation error?    Solved: After extruding away material, your face normals are pointing in the other direction. This causes the miscalculation of calc_volume() as it uses face normals in its algorithm. In order to fix this go into edit mode-->Mesh-->Normals-->Recalculate Inside


If one obtains two entangled in polarization photons by parametric down conversion and one of them is accepted by and electron 1 and other by electron 2 - are this electrons now entangled in spin?


SciFi Movie - Paralyzed man power suit - full recovery (VHS, 90's?)

This was a post apocalyptic movie in which the character is a disabled teacher in a wheelchair. He loves one woman, so he goes to test therapy which is supposed to make him fully functional.  Then company that is providing therapy puts him in a sort of coffin with green goo in it. In order to walk he gets armour but he cannot breathe outside of it.  At the end he kills himself.


Samba net command to shutdown Windows 8 machine

I have a Raspberry Pi for home automation, and I want to be able to shutdown my Windows 8.1 workstation using a command from a bash shell.  Of course I've Googled before asking here. And I found;   net rpc shutdown -s [ipadress] -U username%passsword shutdown -t 1 -f   The net command only works if you;  apt-get install samba-common-bin   But that gives me the error;   Could not initialise pipe \winreg. Error was NT_STATUS_OBJECT_NAME_NOT_FOUND   Of course I have also Googled this error message, but I only find stuff from the Windows XP/Vista age.


Changing the suffix according to the figure number

In Turkish (and possibly in other similar languages), there are suffixes that change corresponding to the word they are applied. This also holds for the numbers.   For example,   in Figure \ref{fig1}   is written in Turkish as follows:  Şekil \ref{fig1}'de   The problem here is that the suffix "de" should change according to the number rendered before it. It should be like  1'de, 2'de, 3'te, 4'te, 5'te, 6'da, ..., 60'ta, ..., 70'te, ...   I don't like to check the suffixes manually after finishing the paper. This also happens for the other cross-references like equations.  How can I do this in LaTeX?   Edit: I'm adding the complete rule as @egreg asks. The determining numbers are as follows:  0'da 1'de 2'de 3'te 4'te 5'te 6'da 7'de 8'de 9'da 10'da 20'de 30'da 40'da 50'de 60'ta 70'te 80'de 90'da 100'de 1000'de 1000000'da 1000000000'da   For all the others, the number at the end determines the suffix if it is non-zero. For example  1234'te  (4'te) 303'te (3'te)   But, if there's a zero at the end and the number is not zero, then the right-most non-zero digit determines the result:  230'da (30'da) 200'de (100'de) 4000'de (1000'de) 40000'de (1000'de) 400000'de (1000'de) 4000000'da (1000000'da)   The suffix is determined by the last read word. For example 40000 is read as "kırk bin" and it becomes "40000'de". It is the same as "1000'de" which is read as "binde".


While running this code I get "JAVA error"  And in the console I see         Connection to db   Connection suceeded   Select * from project.user   1   java.lang.NullPointerException   ...   ...   ...   java.lang.NullPointerException      public void showuser(){   System.out.println("Connection to db");     try {             Connection con = DriverManager.getConnection(url, "", "");             System.out.println("Connection suceeded");             String sql = "Select * from project.user";             System.out.println(sql);             Statement st = con.createStatement();             ResultSet rs= st.executeQuery(sql);             String title[]={"ID","Name","Status","Nomber","Balance","Login","Password"};             DefaultTableModel aModel = new DefaultTableModel();             aModel.setColumnIdentifiers(title);             int i=0;             while (rs.next())             {   Object objects[]= new Object[7];                 i=0;                 while(i<7)                 {                 objects[i]=rs.getObject(i+1);                 System.out.println(objects[i].toString());                 i++;                 }                 aModel.addRow(objects);            }            jTable1.setModel(aModel);            con.close();     }         catch (SQLException ex)         {            while(ex!= null)            {              ex=ex.getNextException();            }            JFrame f1= new JFrame();            JOptionPane.showMessageDialog(f1,"SQL error");                             System.out.println(ex);         }     catch (java.lang.Exception ex)         {             ex.printStackTrace();             JFrame f1= new JFrame();             JOptionPane.showMessageDialog(f1,"JAVA error");                                             System.out.println(ex);         } }


Can I install Microsoft Office? If so, how?

I want to know how to install Microsoft Office (specifically, Microsoft Office 2010) in Ubuntu?   I am a die hard fan of MS Office and I want to know if there is a way I can use it in Ubuntu.


Strange behavior when initializing a list of lists in Python 3

It seems there is an unexpected behavior regarding lists with Python 3.8.1:      > l = [[]] * 4     > l[0].append(1)     > l     [[1], [1], [1], [1]]   I would expect l to be equal to [[1], [], [], []].  Should not the lists inside l correspond to different "objects"?  On the other side the following code behaves as expected.      > l = [ [] for i in range(4)]     > l[0].append(1)     > l     [[1], [], [], []]


It is a remarkable well-stablished fact that the light velocity in vacuum, $c \simeq 3.10^8 m/s$ is the upper limit for the velocity of ordinary matter, never to be achieved.  It is also well-stablished that in different media, the light velocity 'varies': in a higher density medium, for propagating from point A to B, light passes trough electrons and multiple particles, being absorbed and re-emited by some of these particles, than 'slowing down' the process in average, being the net velocity smaller than $c$.  My question is: would there exist known 'materials' (particles or of any kind) to propagate faster than light in such (any) kind of medium (in which light velocity is less than $c$)? It is not against GR and SR, as long as this particles do not exceed $c$.  This is a similar question to this one,    but not considering a man as subject (any material), and mirrors.  This point out to an 'intuitive view' of mine, that in terms of interaction of such particle/materials with the medium it should be considered 'lighter' than light (the interaction)...


I have code that manipulates data of a file that I currently have hard-coded in the script.  I want to be able to prompt the user to chose the input file rather than having to hard-code it.  Here is what I have for input.  Instead of always using myfile.txt, I'd like the user to be able to choose the file:  with open('myfile.txt', 'rU') as input_file:


Windows loads directly without showing the grub menu

I have HP Pavilion 15 Notebook PC preinstalled with Windows 8. I installed ubuntu 14.04 (dual boot) , followed by an upgrade to Ubuntu 15.04. I also upgraded to Windows 10. Recently, due to some reasons, Windows OS directly loads without showing me the Grub menu and letting me select the OS I want to load. I have to press Esc key followed by F9 to see the boot options and select the OS from there. Is there any solution to this problem, without reinstalling Ubuntu?  I want to select the OS I want to load directly from the Grub Menu which should show up on system startup. None of the previous answers related to this question solved my problem.


Can I cancel a download of a Mac Store app?

I just got a really large Mac App Store app, (2GB), but Im having some trouble with my diskspace...   Is there a way to completeley cancel the download of the app? I mean not just pause it but cancel it. The icon on the dock kind of stresses me out, and it reappears even if I drag it out.


How to avoid duplicate entries in .bash_history

The same command is listed in my history again and again. How can I avoid this? I know it's possible via HISTCONTROL but I haven't found the right way.


Suppose a mixture model, having the following distribution function:  \begin{equation} f(x) = \sum_{k = 0}^K \pi_k f_k(x) \end{equation}  where $f_k(x)$ is a Poisson distribution with parameter $\lambda_k$.  Is it possible to have an analytical expression of the quantile function of the mixture model using the quantile function of the individual Poisson component (or the repartition function or any usual function ?) ?


What is the difference between different compiling buttons in winedt?

I am on my first LaTeX homework using winedt. I have just written my hello world code and saved it properly. Now I am wondering which compiling button is the right one to build a PDF file among the five buttons PDFTeXify, PDFLaTeX, PDFTeX, TeXify and LaTeX buttons. How can I differ them?


Are the spaces $\mathbb{H}^n$ and $\overline{\mathbb{R}}^n_+$ homeomorphic?

Let $\mathbb{H}^n = \{(x^1, \dots , x^n) \in \mathbb{R}^n : x^n \ge 0\}$, and $\overline{\mathbb{R}}^n_+ = \{(x^1, \dots , x^n) \in \mathbb{R}^n : x^1 \ge 0, \dots, x^n \ge 0\}$. Endow each set with the subspace topology it inherits from $\mathbb{R}^n$.  Exercise 16.18 on page 415 of Lee's Introduction to Smooth Manifolds (2nd edition) asks us to show that $\mathbb{H}^n$ and $\overline{\mathbb{R}}^n_+$ are homeomorphic.   However, it seems to me the spaces are not homeomorphic, as shown by the following argument.  Suppose $f:  \overline{\mathbb{R}}^n_+ \to \mathbb{H}^n$ is a homeomorphism. Set $f(0, \dots , 0) = (a^1, \dots, a^n)$. Then   $$A = f(\overline{\mathbb{R}}^n_+ \setminus \{(0, \dots, 0)\}) = f((\infty,0) \times \cdots \times (\infty,0)) = \\  ((\infty, a^1) \cup (a^1, - \infty)) \times \cdots \times ((\infty, a^n) \cup (a^n, 0]),$$ where, if $a^n= 0$, then in the last factor we discard $(a^n, 0]$.  The set $A$ is connected as it is the continuous image of the connected set $(\infty, 0) \times (\infty,0)$. But at the same time we see that $A$ is disconnected as it is the union of the disjoint relatively open sets  $(\infty, a^1) \times \cdots \times (\infty, a^n)$ and $ (a^1, - \infty) \times \cdots \times (a^n, 0]$ (or $(\infty, a^1) \times \cdots \times (\infty, 0)$ and $(a^1, - \infty) \times \cdots \times (\infty, 0)$ in case $a^n = 0$).   Is there a  mistake in my argument or something I am missing? Any comments are greatly appreciated.


solving $x^3-2y^3=1$ using cubic number field

I am trying to solve the diophantine equation $x^3-2y^3=1$ using  $\mathbb{Q}(\sqrt[3]{2}).$  I've read this link:   The following is what i have tried:  Finding all integer solutions of $x^3-2y^3=1$ is equivalent to finding all the elements of the form $x + y\sqrt[3]{2}$ in $\mathbb{Q}(\sqrt[3]{2})$ of norm $1$ over $\mathbb{Q}$ where $x,y\in \mathbb{Z}.$ By Dirichlet's unit theorem $\mathcal{O}_{\mathbb{Q}(\sqrt[3]{2})}^{\times} \cong \mathbb{Z}/2 \oplus \mathbb{Z}.$ Thus $x + y\sqrt[3]{2}=±(-1-\sqrt[3]{2})^n$ for some $n\in \mathbb{Z}.$   But then I have to idea how to proceed. In fact, I'm not even sure if what I have tried is correct. Can anyone help me please?


Do I prebook a taxi from Heathrow to London King's Cross?

Is it cheaper to prebook a taxi from Heathrow to get to King's Cross station, or better to find a taxi waiting at the airport? We're flying in from New Zealand.


I installed QGIS 3 as instructed and the Vector processing tab is missing. I did uninstall all previous versions and Python.


I have several very similar images except some have some extra graphics that enlarge them slightly. This causes some pictures to be offset and not aligned visually when it's clear they should be.  How can I align several tikzpictures along the the same origin they were created and center vertically and horizontally properly?   First, I want to align the 3 large boxes regardless of the what the small boxes are doing Second, I want to be able to center them all without adding additional spaces the \begin{center} seems to do Third, I want to be able to reproduce the exact same results but everything in landscape mode without using the landscape package if possible. (as you can see, the problem is that TeX is putting one rectangle at a time which is not what I want) The methods should be easy and quick. I have many rectangles stacked and some need to be grouped arbitrarily. What these means is I want the methods to sort of be "smart" in that they can figure out themselves so I don't have to go change a lot of stuff each time I have to change the grouping. Basically I would like the first rectangle on the page to define the alignment location and the others on the same page to use it unless I tell them not to.   I've tried creating a custom bounding box as shown in  but it didn't do anything unless I make it too large which then causes other problems. (I can end up doing the alignment but it seems more complex than necessary)  \documentclass[10pt]{book} \usepackage{tikz}  \begin{document} \begin{tikzpicture}     \draw[line width=30pt] (0,0) -- (7,0); \end{tikzpicture}  \begin{tikzpicture}     \draw[line width=30pt] (0,0) -- (7,0);     \draw[line width=20pt] (-0.4, 0) -- (-0.1, 0); \end{tikzpicture}  \begin{tikzpicture}     \draw[line width=30pt] (0,0) -- (7,0);     \draw[line width=20pt] (-0.4, 0) -- (-0.1, 0);     \draw[line width=20pt] (-0.8, 0) -- (-0.5, 0); \end{tikzpicture}    \begin{center}% \begin{tikzpicture}%     \draw[line width=30pt] (0,0) -- (7,0); \end{tikzpicture}% \end{center}%  \begin{center}% \begin{tikzpicture}%     \draw[line width=30pt] (0,0) -- (7,0);     \draw[line width=20pt] (-0.4, 0) -- (-0.1, 0); \end{tikzpicture}% \end{center}%  \begin{center}% \begin{tikzpicture}%     \draw[line width=30pt] (0,0) -- (7,0);     \draw[line width=20pt] (-0.4, 0) -- (-0.1, 0);     \draw[line width=20pt] (-0.8, 0) -- (-0.5, 0); \end{tikzpicture}% \end{center}%     \begin{tikzpicture}%     \draw[line width=30pt] (0,0) -- (0,7); \end{tikzpicture}%   \begin{tikzpicture}%     \draw[line width=30pt] (0,0) -- (0,7);     \draw[line width=20pt] (0,-0.4) -- (0,-0.1); \end{tikzpicture}%  \begin{tikzpicture}%     \draw[line width=30pt] (0,0) -- (0,7);     \draw[line width=20pt] (0,-0.4) -- (0,-0.1);     \draw[line width=20pt] (0,-0.8) -- (0,-0.5); \end{tikzpicture}%    \begin{center}% \begin{tikzpicture}%     \draw[line width=30pt] (0,0) -- (0,7); \end{tikzpicture}% \end{center}   \begin{center}% \begin{tikzpicture}%     \draw[line width=30pt] (0,0) -- (0,7);     \draw[line width=20pt] (0,-0.4) -- (0,-0.1); \end{tikzpicture}% \end{center}%   \begin{center}% \begin{tikzpicture}%     \draw[line width=30pt] (0,0) -- (0,7);     \draw[line width=20pt] (0,-0.4) -- (0,-0.1);     \draw[line width=20pt] (0,-0.8) -- (0,-0.5); \end{tikzpicture}% \end{center}%   \end{document}


Find multivariate pdf of a multivariate function

Consider the following function:  $Y(t) = X_1 \exp{(-X_2 t)}$  where the parameters $X_1, X_2$ are random variables and $t$ is the time.  How to find the analytical expression of the probability density function of the function $Y(t)$?


Why is there conservation of kinetic energy in elastic collision and not in inelastic collision?

Why is there conservation of kinetic energy in  and not in ? What would be the difference that lead to conservation of kinetic energy in elastic collision and not in inelastic collision? We also know that mechanical energy is not converted to heat, light, sound etc. in elastic collision but converted to heat, light, sound etc. in inelastic collision. Why is mechanical energy converted as total energy is conserved in inelastic collision?


Barking dogs seldom bite.  Barking is  a gerund or present participle?  His rising early in the morning, helped him score well.  His rising early in the morning   -- is this a participle clause? Can someone explain how to identify an participle clause in any sentence


Right now the flagging history stats are kind of lumped together visually. I'd like to suggest an easy to implement enhancement that would make reading the flagging history stats easier.  By adding some basic visual cues like borders, and placing the percentage statistic after the particular flag type, your history becomes much easier to read at a glance.


Why are we using "Euler's Number" constantly?

I am a student at technical university.We are currently studying Calculus and I am really curious about why we are using Euler's Number.


How do I set my dns nameservers in /etc/resolv.conf without it being overwritten by my isp?

All I want is to set a custom dns name server, to that of  but my resolvconf is getting overwritten by the dns settings set on my router. I can't change the router dns or disable this "feature". If it helps I'm using Telstra as my ISP and my resolvconf looks like this: # This file is managed by man:systemd-resolved(8). Do not edit. # # This is a dynamic resolv.conf file for connecting local clients directly to # all known uplink DNS servers. This file lists all configured search domains. # # Third party programs must not access this file directly, but only through the # symlink at /etc/resolv.conf. To manage man:resolv.conf(5) in a different way, # replace this symlink by a static file or a different symlink. # # See man:systemd-resolved.service(8) for details about the supported modes of # operation for /etc/resolv.conf.  nameserver 84.200.69.80 search resolver1.dns.watch  after being overwritten it defaults to my isp dns


Is it possible to have two mindmaps that share children? This is what I would like to have:  Concept 1 is blue, and has some children.  Concept 2 is red, and has some children.  Concept 1 and two share one child, which is purple.  And this is what I have so far: Concept 1 is blue, and has some children. Concept 2 is blue, and has some children.  \begin{tikzpicture}[small mindmap,concept color=blue!80]   \node [concept] {Root concept 1}     child[clockwise from=270] {node[concept] {child}}     child[clockwise from=270] {node[concept] {child}};   \node [concept] at (5,0) {Root concept 2}     child[clockwise from=225] {node[concept] {child}}     child[grow=0 ] {node[concept] {child}}; \end{tikzpicture}


Given a proper homogeneous ideal, is there always a homogeneous maximal ideal that contains it?

It is known that every proper ideal of a ring must be contained in a maximal ideal, by the Zorn's lemma. Is this true in general for proper homogeneous ideals in a graded ring?


Under certain conditions, the Linux kernel may become tainted. For example, loading a proprietary video driver into the kernel taints the kernel. This condition may be visible in system logs, kernel error messages (oops and panics), and through tools such as lsmod, and remains until the system is rebooted.  What does this mean? Does it affect my ability to use the system, and how might it affect my support options?


Formatting slightly off - count of answers box off edge of background

There has been an apparent CSS change that is infelicitous. When I refreshed some of my stacks, I see the answer-count boxes over the edge of the central area:  This contrasts with the earlier CSS:


How do I ensure all of my extra (internal) hard drives are mounted by default upon boot up of Ubuntu 17.10?

How do I ensure all of my other internal hard drives are mounted by default upon boot up of Ubuntu 17.10?  Every time I start my Ubuntu 17.10 computer and log in, I have to Open "Files" - then Click "+ Other Locations" to see the list of attached devices. Only once I do this am I able to look at the contents of these additional internal hard drives.  Here is my details when I edit fstab   # /etc/fstab: static file system information.  #  # Use 'blkid' to print the universally unique identifier for a  # device; this may be used with UUID= as a more robust way to name devices  # that works even if disks are added and removed. See fstab(5).  #  # <file system> <mount point> <type> <options> <dump> <pass>  # / was on /dev/sda5 during installation  UUID=3b693200-e592-483d-9b74-701739be0c08 / ext4 errors=remount-ro 0 1 /swapfile none swap sw 0 0  /dev/disk/by-uuid/508a6797-6705-48f9-b698-c9b7abb410e2 /mnt/508a6797-6705-48f9-b698-c9b7abb410e2 auto nosuid,nodev,nofail,x-gvfs-show 0 0  /dev/disk/by-uuid/00aa1e3e-f053-4644-804b-e397c60551ba /mnt/00aa1e3e-f053-4644-804b-e397c60551ba auto nosuid,nodev,nofail,x-gvfs-show 0 0   I haven't edited this yet, but this is what I see. It appears as though auto is already there.  Is this a Bios setting or can it be solved by a setting in Ubuntu 17.10? Your advice or help would be appreciated. Thanks, Brett


How can I use a table generated by R in LaTeX?

I have a LaTeX table generated like this,   \begin{table}[ht] \begin{center} \begin{tabular}{rrrrrrr} \hline & 1 & 2 & 3 & 4 & 5 & 6 \\  \hline 1 & 181.21 & 169.01 & 130.03 & 135.93 & 142.31 & 108.11 \\  2 & 106.80 & 130.71 & 186.43 & 126.46 & 167.28 & 137.91 \\  3 & 162.69 & 198.98 & 188.33 & 184.30 & 147.02 & 197.38 \\  4 & 132.42 & 150.50 & 148.69 & 134.31 & 129.52 & 172.72 \\  \hline \end{tabular} \end{center} \end{table}   but when i compile it in MiKTeX I am getting the following error   ! Undefined control sequence. l.1 \begin           {table}[ht] ?  Process interrupted by user   I want a table generated from this i am compiling under pdfTeX. I am using LaTeX for first time, can anyone please give a suggestion?


Why do I see a saddle in this picture of a computer screen?

I am not entirely sure this is an appropriate question for PSE, however since many of you have such diverse backgrounds, I'll give it a shot.  I have noticed that when one takes a picture of a computer, TV screen with a phone, you can "see" what looks like a saddle phase portrait.     Why does this happen? Does it have any relevance to differential equations or other areas of math?


I got an exercise on implementing a javafx-application of Minesweeper to do. I took an excerpt of the code in order to isolate the problem. In the code i read-in an Array of objects of type javafx.scene.control.Button. In another class i read out this array. Like in every javafx Application the whole is brought together in an Application-class. Compiling works. I get a nullPointerException when i run the Programm. That is my problem here. Probably the Array doesn't contain any objects. By the way i use separated classes because the exercise consists in the model-view-controller Designpattern.  import javafx.scene.control.Button;  public class GameButton extends Button {     public static GameButton[][] buttons = new GameButton[3][4];     public GameButton() {       for (int x = 0; x < buttons.length; x++) {          for (int y = 0; y < buttons[x].length; y++) {             buttons[x][y] = new GameButton();   //Read in the array          }       }    } }     import javafx.scene.layout.GridPane;  public class View extends GridPane {    public View() {        for (int x = 0; x<GameButton.buttons.length; x++) {          for (int y = 0; y<GameButton.buttons[x].length; y++) {             this.add(GameButton.buttons[x][y], x, y);// Read out the array          }       }    } }     import javafx.application.Application; import javafx.stage.Stage; import javafx.scene.Scene;  public class Main extends Application {     public void start(Stage stage) {       View view = new View();       Scene scene = new Scene(view);       stage.setTitle("Minesweeper");       stage.setScene(scene);       stage.show();    }     public static void main(String[] args) {       launch(args);    } }


Is it degeneracy pressure rather than electrostatic repulsion that stops us falling through the floor?

From Wikipedia:      Freeman Dyson showed that the imperviousness of solid matter is due to quantum degeneracy pressure rather than electrostatic repulsion as had been previously assumed.   Could someone expand or explain regarding this Wikipedia excerpt as it is, (like most of physics, unfortunately) , a complete surprise to me.  Two questions:   In simple terms, is it possible to show how Dyson demonstrated this? Does it eliminate the role of electrostatic repulsion in ordinary life, such as standing on the floor, or just supplement the electrostatic repulsion effect?   EDIT as noted in the comment below by John1024 The same wikipedia article also states: "At commonly encountered densities, this [degeneracy] pressure is so low that it can be neglected." So, standing on the floor is still an electrostatic effect   but I would still be interested in the derivation and at what densities it applies, presumably neutron star levels.  As dmckee lists below, there are possible duplicates, but unfortunately I don't follow them as well as another year of studying physics would allow me too.  They don't seem to contain, on first looking at least, a derivation of Dyson's conclusion or the density at which one effects supersedes the other.  It's a fascinating area of physics, imo, so any answers  (the simpler the better, although I have studied basic Degeneracy Pressure in neutron stars) to these questions would be greatly appreciated.   END EDIT


Consider a BJT serving as an amplifier. No suppose I need to  subtract the output obtained from two such  BJT amplifiers A1 and A2. Then I can simply  connect the output from A1 to one of the input  terminals of another transistor amplifier A3 and connect the other terminal to the output obtained from A2. In this way I can  obtain the output from A3 as the difference of two signals.    Now similarly suppose I need A non inverting amplifier. Then I can measure the output of a CE transistor amplifier in a reverse way so as to get the output in phase with the input. Now  consider an integrator circuit. When an ac source is connected in series with a resistor and capacitor then if the function to be integrated is taken as the current then obviously the voltage gives the integrand of the function (although multiplied by the capacitance).     In all the above situations I have sen opamps being used. When the circuit arrangement is as simple as mentioned above why do we use opamps(which have complicated internal circuit arrangements)? I don't intend to be a critic but rather I want to know the actual purpose for which opamps are used at the expense of simplicity?


Why does Landsat 8 panchromatic band NOT include the infrared?

The panchromatic band on Landsat 8 OLI sensor (band 8) covers a narrower portion of the spectrum than the corresponding band in Landsat 7 ETM+: 0.50 - 0.68 micrometers (L8 OLI) in contrast to 0.52 - 0.90 micrometers (L7 ETM+) (see complete tables ). Most remarkably, L8 OLI band 8 does not cover the near infrared, thus precluding pan sharpening in that portion of the spectrum and making up a significant difference with the L7 ETM+ panchromatic band. Why?  In this interesting , the author mentions the issue without being able to find the logic behind it, and citing the explanation given by Irons et al (2012) “The OLI panchromatic band, band 8, is also narrower relative to the ETM + panchromatic band to create greater contrast between vegetated areas and surfaces without vegetation in panchromatic images" as not clear or insufficient, and hinting to possible design glitches.  I am also left wondering about this and could not find a decent explanation anywhere. Does anyone in this forum know why?  Irons, J.R. et al. (2012) The next Landsat satellite: The Landsat Data Continuity Mission. Remote Sens. Envion.,122, 11-21. doi:10.1016/j.rse.2011.08.026


I'm pretty depressed that I'm finally one of the people posting this, since I'm usually telling those people "you're obviously wrong", but either I don't understand how consecutive day counting works or this seems impossible:    The last activity count is right; I was on SO at about 18:30Z yesterday (Saturday). Is it possible for the consecutive count to be at 1 if my last activity was yesterday? It would seem like it has to be at least 2 then (although I was definitely active Friday; I suspect Saturday is the "missing" day since all I did was poke through the newest question list and check the current flags)


How can I get a copy of a ArrayList() object instad of a refrence;

if I ge  ArrayList<String> myList; // add some stuff to myList ArrayList<String> copyOf=myList;   copy will be a reference to myList, thus if I change copyOf, myList will change to. Hpw can I make coyyOf be a copy of myList, so if copyOf chnages, myList will not change.


Minimum Windows XP is required for installing dotnet

I installed ubuntu 12 and 14 32 bit operating system and sudo apt-get update and added wine respository and installed wine using sudo install. After that I'm trying to install dotnet framework. But it is showing errors like xmono and I got error that your system is Windows ME etc inorder to install dotnet framework your system should support minimum windows XP.   What would be the solution for this.


biblatex: reference both by chapter and at the end of the book

I currently print my references after the end of each chapter, using:  \usepackage[backend=biber,     bibencoding=utf8,     refsection=chapter,     style=numeric,      firstinits=true,     isbn=false,     doi=true,     url=false,     clearlang=true ]{biblatex}   and   \printbibliography[heading=subbibliography]   at the end of each chapter.  I would like to have also a chapter at the end of the book with all cited references. How could I do ?


Ubuntu reports in dmesg:  DMI: Hewlett-Packard HP ProDesk 490 G1 MT/18EB, BIOS L02 v02.01 09/22/2013   But I cannot find information about this  anywhere.  I do can check (almost) every single piece of hardware (various chips, the controllers, the ethernet, the audio and so on) but that's not the motherboard. Every motherboard make and model is actually unique.  Whatever tool I'd use I wouldn't get any more details from what the kernel.  I do know what is my hardware (read the quoted text). I simply don't know anything more than the bare name.  I would like to know, for example, the chipset brand/model and other MB-related stuff. No way, no matter the tool I use.  How can I know details about the motherboard I am using without opening the case?  Is there anyone knowing anything about it? Or simply, this cannot be done even in the twenty first century?


I am writing a simple code trying to read 2d vector by using template. But get error like:  Severity    Code    Description Project File    Line    Suppression StateError  LNK2019 unresolved external symbol   My main.cpp is like:  #include "header\\read_2d.h" #include <iostream>   #include <fstream> #include <vector> #include <string> #include <stdlib.h> using namespace std;  int main() {     //input image array parameters and initialize a 2D array     int nx = 200;     int ny = 200;     std::vector<std::vector<unsigned char> > image(nx, std::vector<unsigned char>(ny));     std::vector<std::vector<unsigned char> > mask(nx, std::vector<unsigned char>(ny));     string disk_filename = "disk.dat";      //read image     read_2d<unsigned char>(disk_filename, image);      return 0;  }   My read_2d.h file is:  #ifndef READ_2D_H    // To make sure you don't declare the function more than once by including the header multiple times. #define READ_2D_H   #include <iostream>   #include <fstream> #include <vector> #include <string> using namespace std;  template <typename myType> void read_2d(string filename, vector< vector<myType> >& image);  #endif   My read_2d.cpp is:  #include "..\\header\\read_2d.h" using namespace std;  template <typename myType> void read_2d(string filename, vector<vector<myType> >& image) {      int nx = image.size();     int ny = image[0].size();     int sizeOfData = nx*ny*sizeof(myType);     std::vector<char> raw_data(sizeOfData);     std::ifstream inputFile;      inputFile.open(filename.c_str(), ios::binary);      if (inputFile.is_open()) {         inputFile.read(&raw_data[0], sizeOfData);         inputFile.close();          for (int i = 0; i < nx; i++) {             memcpy(&image[i][0], &raw_data[(i*ny)*sizeof(myType)], ny*sizeof(myType));         }      }     else {         cerr << "Input file for " << filename << " could not be opened...\n" << endl;         exit(EXIT_FAILURE);     }  }   Can any one help me point out what I have done wrong? Any comments will be very much appreciated!


Help with Controller Extension Test Class,

I have a very simple controller extension and I'm trying to write a test Class, but I am only able to get 12% coverage. I'm not sure how to cover the rest of thelines below. Right now only my constructor is being covered: Controller Extension public class AcctAddresses {           public List<Account_Addresses__c> addresses{get;set;}      public string DelAddrId { get; set;}      public Account accounts {get;set;}       public Account acct {get;set;}        //Constructor       public AcctAddresses(ApexPages.StandardController controller) {           acct = (account)controller.getRecord();                accounts = [SELECT Id                     FROM account                     WHERE id=: acct.id LIMIT 1];           addresses = [SELECT Id, Primary__c, Street__c, City__c, State__c, Zip_Postal_Code__c, Country__c, Account__c                     FROM Account_Addresses__c                     WHERE Account__r.Id = :accounts.id ORDER BY Primary__c, State__c];       }     //This method is to delete the contact record while clicking the Del link       public pageReference deleteAddress(){          Account_addresses__c ToBeDeleted = [SELECT Id FROM Account_addresses__c WHERE id = : DelAddrId LIMIT 1];           delete ToBeDeleted;           String baseUrl = URL.getSalesforceBaseUrl().toExternalForm();           PageReference redirectPage = new PageReference(baseUrl+'/'+acct.id);           return redirectPage;        }     }  Test Class @isTest  private class AcctAddressesControllerTest {      static testMethod void testMethod1()      {         Test.StartTest();          Account testAccount = new Account();             testAccount.Name = 'Test JN Account';             testAccount.AccountSource = 'Networking';         insert testAccount;                  Account_Addresses__c testAcctAddr = new Account_Addresses__c();             testAcctAddr.Account__c = testAccount.Id;             testAcctAddr.Street__c = '1010 Test Ave';             testAcctAddr.City__c = 'New York';             testAcctAddr.State__c = 'NY';             testAcctAddr.Zip_Postal_Code__c = '11212';             testAcctAddr.Country__c = 'USA';             testAcctAddr.Primary__c = TRUE;             testAcctAddr.Current__c = TRUE;         insert testAcctAddr;          ApexPages.StandardController AcctAdd = new ApexPages.standardController(testAcctAddr);         AcctAddresses AcctAdd1 = new AcctAddresses(AcctAdd);         Test.setCurrentPageReference(new PageReference('Page.Acct_Addresses'));         Test.StopTest();     } }


Let $m(\cdot)$ denote Lebesgue measure.  Does there exist an $S\subset [0,1]$ such that for all $a<b$ we would have $0<m([a,b]\cap S)<b-a$?  I believe that the answer is yes, and I have a rough construction in mind.  On the first step, allocate $1/4$ "mass" to either side of $1/2$ (this gives $S_1$).  Then recursively allocate $1/8$ mass to either side of $1/4$ and of $3/4$ (to get $S_2$).  Continue this process.  At depth $d$ of the recursion, we have that for $a,b$ with binary expansions with at most $d$ digits, $m([a,b]\cap S_d)=(b-a)/2$.  Then in the limit, any interval can be written as the countable disjoint union of intervals with finite binary expansion, so (I think) $m([a,b]\cap S_d)=(b-a)/2$ holds for all $0<a<b<1$.  I can describe the construction a bit more formally:  For every $n$, consider the set of points with $n$ digits in its binary expansion.  There are $2^{n-1}$ such points since every digit is free, except for the last one which must be 1.  Place an interval of length $2^{-n}$ centered at each of those points.  Let $S_n$ be the union of those intervals.  This would give us $S_1=[1/4,3/4],S_2=[1/8,3/8]\cup [5/8,7/8],\cdots$


How Can I Batch Change the Metadata of MP3 Files?

I have a fews of songs in a folder which I would like to add the metadata items of artist, title, genre and album to. I would like to take the metadata info for the title and artist from the file name itself.   For Example: I have a song file named Melvv - Glide.mp3. I would like to take the name of the artist Melvv and the title of the song Glide from the file name and add it as MetaData. For the Album and Genre, I'll add this in myself.   Is there a way I can do this in the Linux environment via bash or python? Is there a way this can be done in the Windows environment?


Are there distinct integers $A,B,C \in \mathbb{Z}$ such that $A^e + B^e=C^e$

This question is a variant of the pythagorean relation except that 2 was replaced by $e=2.71828...$


Express $1 + \frac {1}{2} \binom{n}{1} + \frac {1}{3} \binom{n}{2} + \dotsb + \frac{1}{n + 1}\binom{n}{n}$ in a simplifed form

I need to express $$1 + \frac {1}{2} \binom{n}{1} + \frac {1}{3} \binom{n}{2} + \dotsb  + \frac{1}{n + 1}\binom{n}{n}$$ in a simplified form.  So I used the identity $$(1+x)^n=1 + \binom{n}{1}x + \binom{n}{2}x^2 + \dotsb   + \binom{n}{n}x^n$$ Now on integrating both sides and putting $x=1$.  I am getting $$\frac{2^{n+1}}{n+1}$$ is equal to the given expression.But the answer in my book is  $$\frac{2^{n+1}-1}{n+1}.$$ Where does that -1 term in the numerator come from?


How to read text file with 1Ah char in it?

I have a file, which is an assembly source with comments. These comments contain 1Ah character. It is a control character, the "substitute", but it also prints a nice right arrow in DOS, so someone long time ago thought it would be a shame not to use it.  Somehow, it works like end of file character for Python. All I do is:  f = open('file.asm') for line in f:     print line f.close()   And everything goes ok just until the first entrance of 1Ah.   The question is, how to read this symbol along with other text?


Using PHP I am posting an array of form inputs to a database, then sending this data via email.   The variable $mac_address_array = $_POST['MacAddress'] is an indexed array.   A print_r($_POST) displays the following;  [MacAddress] => Array     (         [0] => 333         [1] => 444     )   I would like to send this data via email, formatted on separate lines if possible. My email script works, however only when I use the following code in my email script;  mail($recipient, $subject, print_r( $mac_address_array, true ), $headers);   I successfully receive the email, but values are displayed like this;  Subject,  Array ( [0] => 333 [1] => 444 )   Is there any way I can display them like this;  Subject,  - MAC Address 1: 333 - MAC Address 2: 444   I know I need a foreach loop somewhere, this is where I'm stuck!  Any advice is appreciated.


bash: count the number of lines with unique initial value

I have a text field that has lines with the following format:  game,match_num,list_of_players,game_date   Eg:  Football,1,james,john,jack,09-10-2018   I need to compare lines in the file based on the game and count only the unique lines i,e., count if the game name is not equal. How can I do this using sed or awk?   Something like this:   wc -l filename | awk -F, '$1 != $1'   I did not get any output for this command but I want to get the number of lines. So how should I change this command to get the desired output?


How to create two different title pages with the \maketitle command?

I would like to create two different title pages (one with the author information and the thanks notes and one without) by using the \maketitle command. Repeating the commands one after another wasn't successful.    Using the \titling package creates the same title, even though I enter an empty field for the author (i.e., \author{}) and insert no \thanks notes after the title.   Is there an elegant and an easy way to create two different title pages with different information? I would be glad, if someone can help me here.   Here is the code I tried running with the \titling package, which repeats the same titlepage:  \title{Title text\thanks{Thanks}}  \author{Author Name}  \date{D}  \begin{document}  \pagenumbering{roman}  \oneandhalfspacing  \begin{titlepage}  \maketitle   \date{}  \begin{abstract}  \spacing{2}  \thispagestyle{empty}  Some text for the abstract  \end{abstract}  \end{titlepage}  \begin{document}  \pagenumbering{roman}  \oneandhalfspacing  \begin{titlepage}  \maketitle  \date{}  \title{Title Text}  \author{}  \date{}  \begin{abstract}  \spacing{2}  \thispagestyle{empty}  \date{}  Some text for the abstract  \end{abstract}  \end{titlepage}  \newpage  \pagenumbering{arabic}  \spacing{2}  \section{Introduction}


How do i use a variable to construct a sequence?

This, of course, works:  $ echo {1..5} 1 2 3 4 5   But when i attempt to substitute the number 5 with a variable, this no longer works:  $ f=5; echo {1..$f} {1..5}  $ f=5; echo {1..${f}} {1..5}  $ f=5; echo {1..f} {1..f}   Is there a way to substitute the number within a variable before the {#..#} construct is parsed?


Why is the probability zero for any given value of a normal distribution?

I noticed that in the Normal distribution, the probability $P(x=c)$ equals zero, while for the Poisson distribution, it will not equal zero when $c$ is a non-negative integer.  My question is: Does the probability of any constant in the normal distribution equal zero because it represents the area under any curve? Or it is just only a rule to memorize?


How do I create a dd IMAGE from LVM for recovery purposes

How do I backup a LVM partition to an image for recovery purposes?  I am trying to run dd on /dev/sda2, but it crashes after ca 8 hours, at around 380G   sudo lvmdiskscan   /dev/centos/swap [       3.89 GiB]    /dev/sda1        [     500.00 MiB]    /dev/centos/root [      50.00 GiB]    /dev/sda2        [     465.27 GiB] LVM physical volume   /dev/centos/home [     411.38 GiB]    /dev/sdb1        [     931.51 GiB]    3 disks   2 partitions   0 LVM physical volume whole disks   1 LVM physical volume   Anyway, could running from a stick make any difference?


What is the physical meaning of commutators in quantum mechanics?

This is a question I've been asked several times by students and I tend to have a hard time phrasing it in terms they can understand. This is a natural question to ask and it is not usually well covered in textbooks, so I would like to know of various perspectives and explanations that I can use when teaching.  The question comes up naturally in what is usually students' second course in quantum physics / quantum mechanics. At that stage one is fairly comfortable with the concept of wavefunctions and with the Schrödinger equation, and has had some limited exposure to operators. One common case, for example, is to explain that some operators commute and that this means the corresponding observables are 'compatible' and that there exists a mutual eigenbasis; the commutation relation is usually expressed as $[A,B]=0$ but no more is said about that object.  This naturally leaves students wondering     what is, exactly, the physical significance of the object $[A,B]$ itself?   and this is not an easy question. I would like answers to address this directly, ideally at a variety of levels of abstraction and required background. Note also that I'm much more interested in the object $[A,B]$ itself than what the consequences and interpretations are when it is zero, as those are far easier and explored in much more depth in most resources.    One reason this is a hard question (and that commutators are such confusing objects for students) is that they serve a variety of purposes, with only thin connecting threads between them (at least as seen from the bottom-up perspective).   Commutation relations are usually expressed in the form $[A,B]=0$ even though, a priori, there appears to be little motivation for the introduction of such terminology. A lot of stock is placed behind the canonical commutation relation $[x,p]=i \hbar$, though it is not always clear what it means.  (In my view, the fundamental principle that this encodes is essentially de Broglie's relation $\lambda=h/p$; this is made rigorous by the  but that's quite a bit to expect a student to grasp at a first go.) From this there is a natural extension to the Heisenberg Uncertainty Principle, which in its general form includes a commutator (and an anticommutator, to make things worse). Canonically-conjugate pairs of observables are often introduced, and this is often aided by observations on commutators. (On the other hand, the energy-time and angle-angular momentum conjugacy relations cannot be expressed in terms of commutators, making things even fuzzier.) Commutators are used very frequently, for example, when studying the angular momentum algebra of quantum mechanics. It is clear they play a big role in encoding symmetries in quantum mechanics but it is hardly made clear how and why, and particularly why the combination $AB-BA$ should be important for symmetry considerations.  This becomes even more important in more rigorous treatments of quantum mechanics, where the specifics of the Hilbert space become less important and the algebra of observable operators takes centre stage. The commutator is the central operation of that algebra, but again it's not very clear why that combination should be special. An analogy is occasionally made to the Poisson brackets of hamiltonian mechanics, but this hardly helps - Poisson brackets are equally mysterious. This also ties the commutator in with time evolution, both on the classical side and via the Heisenberg equation of motion.   I can't think of any more at the moment but they are a huge number of opposing directions which can make everything very confusing, and there is rarely a uniting thread. So: what are commutators, exactly, and why are they so important?


Logging of each working method as default in log4net?

The question is actually this; I need info message for every method's start and end. For example I have a code block:      public void MethodName(ObjectName object)         {             try             {              LOG.Info(MethodBase.GetCurrentMethod());                // Some codes in here             }             catch (Exception e)             {                 LOG.Error(e.Message);             }         }   I don't want to write Log.Info for every method. Any suggestion ?


Every now and again I have been noticing the following in Haskell documentation: (for example in ):     Subject to fusion   What is fusion and how do I use it?


I wrote a C program, expecting to see the difference between uid and euid with setuid bit enabled: #include <unistd.h> #include <stdio.h>  int main(void) {     printf("euid: %d\n", geteuid());     printf("uid: %d\n", getuid());     return 0; }  Then I compiled them in my home directory and /tmp directory respectively but got different results. The script I used to compile and run the two programs: #!/bin/bash  echo in current directory sudo gcc -o a.out a.c sudo chmod u+s a.out ./a.out  echo  echo in /tmp sudo gcc -o /tmp/a.out a.c sudo chmod u+s /tmp/a.out /tmp/a.out  The result of the executation: in current directory euid: 0 uid: 1000  in /tmp euid: 1000 uid: 1000  The setuid bit didn't work in /tmp! I wonder why. I mv the /tmp/a.out to my home directory and the setuid bit worked, so I guess there is something to do with the /tmp directory?


Which wire is the positive and which the negative on this fan?

Here is link with the picture of the fan:    The fan name is "ZALMAN ZM-F3(SF) 120MM ULTRA QUIET FAN"  I looked it up online, but I don't understand, I'm colourblind and it's difficult to distinguish the colors.


Approving/rejecting edits made by the OP to an accepted answer

I've just been presented with a suggested edit to an  - but the edit was proposed by the OP himself, in which he clarified that the answer was right, but with a few tweaks/revisions which he wanted to communicate to viewers. He didn't amend the answer, but appended clearly-labelled comment and code.  I hovered over the accept button, but wanted to check and couldn't find any specific guidance.  In the meantime, ironically, the suggested edit has been rejected by another user...  Is there any accepted guidance for OP comments in an accepted answer? Or is it purely down to judgement?   In my opinion, what was being proposed as an edit was valuable, but I questioned whether it was the right place for such an edit.


Limit of integral expression approaches maximum of function

So I've been trying to find a solution for this all afternoon, but haven't found a good place to start:     Prove that if $f:[a,b]\to\mathbf{R}^+$ is a continuous function with maximum value $M$, then    $$ \ \lim_{n\to\infty}\left(\int_a^b f(x)^n\,dx\right)^{1/n} = M $$   Here are some of the paths I've considered, though none have been very successful:  (1) Considering the sequence of functions for all increasing integer $n$ and trying to show that the sequence converges. We've had plenty of work on converging sequences, but with the integral expression, I am not sure how to simplify.  (2) Showing that that sequence is increasing (again, how?) and then showing there to be a supremum at $M$. I'm not sure how the maximum of the function arrives in this problem.  (3) Mean value theorems for integrals  If anyone could give me a solid place to start or perhaps point me to a place where this question has been asked before (I can't seem to find it), I would be very grateful.


Have iptables run command/script on new connection attempt

How can iptables run a command or script on a new connection attempt?  Requirement:  External packet to (server interface eth0) ---> (Server interface eth0) input table detects new packet received on port 22 --> iptables runs a command or script  Me thinks, so far, for example:  iptables -A INPUT -i eth0 -p tcp --dport 22 -s xxx.xxx.xxx.xxx/24 -d xxx.xxx.xxx.xxx/32 -m state --state NEW (then do something here like run a script or command (but how?) ) -j ACCEPT   Further reading from a similar question with two answers:


Bbq pork ribs accidentally started cooking in crock pot on warm for 2 1/2 hours before noticed

I put country style pork ribs in my crock pot this morning with bbq sauce and didn't realize I set the control to only warm. It was not noticed until it had been on warm for about 2 1/2 hours. I immediately turned it to high.  Will they be safe to eat after cooking on high for a few hours and low for a couple more?


If a question ends in the abbreviation of et cetera, do you still add the period before the question mark?

Possible Duplicate:          Example:   How do I pay for the bananas, oranges, etc.?    or  How do I pay for the bananas, oranges, etc?


I have to show whether the groups $(\mathbb{C}, +, 0)$ and $(\mathbb{C} − \{0\}, \times, 1)$ are isomorphic. I know that two groups are isomorphic if there exists an isomorphism from one to the other. An isomorphism from $G_1$ to $G_2$ is a bijective homomorphism. We call $G_1$ and $G_2$ isomorphic, and write $G_1 \cong G_2$ if an isomorphism from $G_1$ to $G_2$ exists. I tried the following by using the lecture notes: $\varphi:\mathbb{C}− \{0\} \mapsto \mathbb{C}$, then $x\in \mathbb{C}−\{0\}$, and $\varphi(x)\in \mathbb{C}$, then $|x|=|\varphi(x)|$. Now note that the element $i\in \mathbb{C}−\{0\}$ has order $4$. However, no element in $\mathbb{C}$ has order $4$, I think???. Hence, no isomorphism can exist. Hence, the groups $\mathbb{C}−\{0\}$ and $\mathbb{C}$ are not isomorphic. Any tips or help would be grateful!


How do I render a viewport animation that includes the visible name of each object?

I have a scene with a lot of object names visible in the viewport. However, when I render a preview viewport animation, the names are no longer visible. I went through as many settings and preferences as I could, hunting around for an option that would allow me to render with object names visible, but I couldn't find anything. Is there a way to do this, and if so, how?


I need your help please. How can I typeset this set (in the picture blew) in Latex. I even failed to write an attempt. I appreciate your help. Thanks in advance.


Can non-EU wife (Leave to Remain Visa) queue with British citizen at LHR?

My wife is Mexican whilst I am British. We recently married and she has a Spousal/Partner Visa (Leave to Remain)  I presumed that when returning from a holiday to Mexico, my wife would have to queue separately from me because she is from outside the EU, but upon talking to a work colleague, I'm told this may not be the case.  Does anyone know if my wife can join the same queue as me when we return to London Heathrow?


How can I login to my local drupal site 8.3.1 which was under maintence mode

I just logout to see what will the home page look like. Now, I can't login into my local site.


how to upgrade unsupported release when `apt-get update` fails

I need to upgrade my OS because Kubuntu 19.10 is apparently "end of life" and no longer allows updates.  The update instructions I find say apt-get update && apt-get dist-upgrade.  But apt-get update fails: Ign:1 http://us.archive.ubuntu.com/ubuntu eoan InRelease Ign:2 http://us.archive.ubuntu.com/ubuntu eoan-updates InRelease Ign:3 http://us.archive.ubuntu.com/ubuntu eoan-backports InRelease Ign:4 http://security.ubuntu.com/ubuntu eoan-security InRelease Err:5 http://us.archive.ubuntu.com/ubuntu eoan Release   404  Not Found [IP: 91.189.91.39 80] Err:6 http://security.ubuntu.com/ubuntu eoan-security Release   404  Not Found [IP: 2001:67c:1562::15 80] Err:7 http://us.archive.ubuntu.com/ubuntu eoan-updates Release   404  Not Found [IP: 91.189.91.39 80] Err:8 http://us.archive.ubuntu.com/ubuntu eoan-backports Release   404  Not Found [IP: 91.189.91.39 80] Get:9 https://download.docker.com/linux/ubuntu eoan InRelease [43.0 kB] Hit:10 http://archive.canonical.com/ubuntu eoan InRelease Hit:11 http://repository.spotify.com stable InRelease Hit:12 https://packages.riot.im/debian default InRelease Ign:13 https://dl.bintray.com/stripe/stripe-cli-deb stable InRelease Get:14 https://dl.bintray.com/stripe/stripe-cli-deb stable Release [1,840 B] Get:15 https://dl.bintray.com/stripe/stripe-cli-deb stable Release.gpg [821 B] Get:16 https://weechat.org/ubuntu eoan InRelease [3,997 B] Get:17 https://dl.bintray.com/stripe/stripe-cli-deb stable/main amd64 Packages [6,036 B] Get:18 https://weechat.org/ubuntu eoan/main Sources [3,891 B] Get:19 https://weechat.org/ubuntu eoan/main i386 Packages [4,972 B] Get:20 https://weechat.org/ubuntu eoan/main amd64 Packages [4,960 B] Reading package lists... Done E: The repository 'http://us.archive.ubuntu.com/ubuntu eoan Release' no longer has a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details. E: The repository 'http://security.ubuntu.com/ubuntu eoan-security Release' no longer has a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details. E: The repository 'http://us.archive.ubuntu.com/ubuntu eoan-updates Release' no longer has a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details. E: The repository 'http://us.archive.ubuntu.com/ubuntu eoan-backports Release' no longer has a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.  On too many occasions I've had apt render my computer unusable.  So I'm not willing to try apt-get dist-upgrade given that apt-get update can't even run successfully. I saw some hackish looking solution about running sed on /etc/apt/sources.list, but it was also 10 years old (not trustworthy) so I didn't try it. I can't install or update any software now.  And the first command in the upgrade in  fails.  I'm stuck.  How do I get unstuck?


Is there another way to replace \addchap in Latex?

I am using \addchap it does not seem to work in my code when I dont include \usepackage{unnumberedtotoc}, when I include\usepackage{unnumberedtotoc} it works but I still get some errors like command\nonumberline already defined    and command\addxcontentsline already defined. Anyway I want to know if I can get rid of \addchap by using another command here is the code:  \immediate\write18{makeindex \jobname.nlo -s nomencl.ist -o \jobname.nls} \documentclass[12pt]{report} \usepackage[utf8]{inputenc} \usepackage{graphicx} \usepackage[french]{babel} \usepackage{setspace} \setcounter{secnumdepth}{4} \setcounter{tocdepth}{4} \usepackage{unnumberedtotoc} %https://github.com/johannesbottcher/unnumberedtotoc/ \usepackage[automark, plainheadsepline, headsepline, plainfootsepline, footsepline, markcase=ignoreupper]{scrlayer-scrpage} \ihead*{\leftmark} \cfoot*{\pagemark} \setkomafont{pageheadfoot}{\scshape} \usepackage{titlesec} \def\frenchlistfigurename{Liste des figures} \usepackage[a4paper,right=20mm,left=25mm,top=26mm, bottom=26mm]{geometry} \makeatletter \titleformat{\chapter}[display] {\normalfont\huge\bfseries}{\chaptertitlename\ \thechapter}{20pt}{\Huge} \titlespacing*{\chapter}{0pt}{0pt}{20pt} \makeatother \title {Title of the thesis} \titleformat{\paragraph} {\normalfont\normalsize\bfseries}{\theparagraph}{1em}{} \titlespacing*{\paragraph} {0pt}{3.25ex plus 1ex minus .2ex}{1.5ex plus .2ex}    \usepackage[thin, , thinc]{esdiff}   \usepackage{nomencl}   \begin{document}  \doublespacing \maketitle \tableofcontents  \addchap{Publications et communications}  \section*{$\:$  a. Publications:} \section*{$\:$  b. Communications:} \addchap{Remerciements} \end{document}


Why does Pluto's orbit cross Neptune's orbit? Is this a fault in Newton's law of gravitation?


Setting the same min/max for multiple raster layers QGIS

I have 268 hgt-files from  that I'm using to create an elevation model, but each of the files has its own min and max-value in Layer Properties - Symbology - Band Rendering.  Currently it looks like this:    I found I can set the min and max of each layer manually, to get an uniform scale, but this is a hassle for all 268 layers. So I was wondering if I'm missing an option somewhere, or if im doing something completely crazy?


I have a Canon Rebel XS that I bought approx. 5 years ago. Just recently I noticed that I am not getting 3 frames per second anymore. (It was definitely getting 3 before.)   I shoot in the the large JPG format (not RAW) and I use a SanDisk Ultra SDHC 16GB memory card. (The speed does not increase if I shoot in small JPEG.)   I did some tests to see what I was actually getting. In manual, 1/500, f/5.6, auto focus off and continuous shooting mode; I'm shooting about 0.91 frames/second. Not cool.  Any ideas why this might be happening?


Does eating infected flesh have an effect?

I don't remember what actually happends when people eat infected flesh. I have in mind :  Gareth and the cannibals eating bitten Bob's leg in . It seems that the cannibals survive for a while after eating Bob's flesh and they seem OK.  The Saviors eating pigs that ate walkers in . We don't know for how long this process has been on, but  has his routine and looks used to doing that. Can we assume that Saviors are eating infected pig flesh for a while now ?  Does it have negative effect in long term ?


Functions of Independent Random Variables

Is the claim that functions of independent random variables are themselves independent, true?   I have seen that result often used implicitly in some proofs, for example in the proof of independence between the sample mean and the sample variance of a normal distribution, but I have not been able to find justification for it. It seems that some authors take it as given but I am not certain that this is always the case.


Equations for an object moving linearly but with air resistance taken into account?

I know (from Kinematics) that for an object moving linearly with an acceleration and without air resistance the following equations can be used to determine v(velocity) or x(position of the object) at any time:  $v=v_0+at$  $x=x_0+v_0t+\frac{1}{2}at^2$  Where $x_0$ is the position of the object at the start of accelerated movement, $v_0$ is the velocity at the start of the motion and a is the acceleration.  Now if I want to add air drag, say we take the formula for air drag as:  $D=0.5CA\rho v^2$  $C$ is a coefficent, $A$ is the reference Area, $\rho$ is the density and $v$ the velocity. Since $D$ is a force the air drag results in an acceleration, so in other words: The resulting acceleration is $a-D/m$, however $D$ depends on $v$, which depends on the acceleration. And that's where my problem is, I simply can't wrap my mind around that.  How would I go about getting the Equations for $x$ and $v$ including air drag (and don't forget there's acceleration too)?