In the Harry Potter books and films, we saw that Expecto Patronum is mainly used for tackling Dementors and Lethifolds. But what (if any) are other things that Expecto Patronum can be used for?  In-universe references only, please.
Inspired by :  In my answer, I had stated that Patronuses appear to not be physical beings because they have no effect on anything other than Dementors.     They don't cause leaves to stir in the movies. They passed straight through the tent. They don't appear to be bound by normal laws pf physics and can travel great distances almost immediately (Shacklebolt was presumably in London when his Patronus issued the warning). They can apparently walk across water without sinking (as they did in The Prisoner of Azkaban). They can jump, walk, and float in mid-air (as seen in the Room of Requirement in the movie version of The Order of the Phoenix). They make no footprints in lightly powdered snow (The Deathly Hallows Chapter 19) and make no sound of crunching snow as Harry does (further down the same page in Chapter 19).   I stated incorrectly that the only place in canon where there is an exception is with Dementors, where the Patronus physically fends them off with its horns.  A Dementor is clearly a physical being, if it prised Dudley's mouth open and (in the movie anyway) physically slid open the train door.)   Based on comments and further thought, I can think of at least two other examples when a Patronus interacts physically with a physical being.   As pointed out by Slytherincess, a Patronus can fend off a Lethifold (Living Shroud). When training, the Patonus took form against a Boggart, which had taken the form of a Dementor.   All three of these things have, AFAIK, only three things in common (but I may be off).   They are evil They are magical They are, indeed, physical beings.   So the question is, why can a Patronus interact with all three of these, but seems to have no physical effect on everyday things?
Short story about aliens who want to trade items for information, stories, jokes etc I'm trying to figure out the name of a movie I saw on TV as a kid, in the mid-to-late 90s, in the US, in English, on daytime TV.  I remember it being kind of Starship Troopers-esque, but everyone had these glowing lights in their chests.  They glowed in different colored patterns, and I think it had something to do with whether you were attracted to someone or not (I was probably like 7 when I saw it, I didn't really understand the context of that part yet). zsh I/O redirection: redirecting and then piping; what is going on? Can somebody explain what is going on in this command:  echo foo &gt;&amp;2 | grep foo   Zsh (5.0.2) prints foo twice. One seemingly to stdout and one to stderr, since running these commands:  { echo foo &gt;&amp;2 | grep foo } &gt;/dev/null   and:  { echo foo &gt;&amp;2 | grep foo } 2&gt;/dev/null   both just print foo once. Bold italic vectors I am trying to display vectors as bold and italic. The command \mathbf sets the letters non-italic. I also googled a bit and stumbled upon \mathbf{\em y} or \mathbfit{y}, which all didn't work.  I hope someone can help me on this. I need to round the edges of this object.  The bottom edges are going to be rounded in conjunction with another object, so, I guess, this should be left out right now.  I tried using the bevel tool (and a bevel modifier) on an edge (series of Blender edges), but I got the problems you see on the images. When selecting all edges, the bevel doesn't know any limit and isn't applied symmetrically.  When selecting only the edges shown (or only the other ones), I can't proceed with the rest of the bevel, and strange little artifacts appear.  FYI: The top surface is derived from an icosphere.    Without the subdivision shown above, a stair comes into existence (bad):    Whole object: How can I configure the Ubuntu Dock to show windows only from the current workspace? I would like my Dock to show only the windows of the current workspace. Especially in the little preview window. I find it very confusing to jump around workspaces when trying to find the right window. Can I choose not to defend against an attack? Playing D&amp;D4e, I have a situation in mind where a character could reasonably WANT to get hit with a normally harmful attack. Is there anything in the rules allowing the character to purposefully take the hit, not even bothering to attempt to defend or dodge out of the way of it?  For example, a dragonborn character makes a breath attack that includes an ally in its blast. The dragonborn has the Nusemnee's Atonement feat, which allows a player whose AOE damages an ally to take the ally's damage instead. This can be paired with a dragonborn feat that recharges your racial dragonbreath power when you take damage of the type it deals. This combination lets the dragonborn recharge their dragonbreath as long as they hit an ally with it. Normally you'd want your ally to at least have a chance to dodge your AOE first, but in this combo, it's best if they can allow themselves to get hit!  Can the ally choose not to defend against the attack, purposefully taking the hit, knowing that the character making the attack will take the damage in his place? A tool to measure signal strength of wireless I want to know if there exists any command line option or GUI tool (Ubuntu 11.10) so that I can measure the strength of wireless signal at a given location. I have a house where the wireless is not easily accessible at all corners I want to know at which corners or rooms the signal is weak. count() returns a different amount than a simple select I managed to successfully publish my old bachelor thesis in a good quality national journal in my country. However, I am thinking of retracting the article due to certain circumstances. First, I felt really embarrassed by the low quality research methodology used in my bachelor thesis. I only used simple correlation in my research. After it was published, I realized that the journal editor team forgot to include a reference in that article because they were rushing me throughout the editing process. I informed them about their mistake and it seems that they have done nothing to fix the problem. I became a bit annoyed because the editor team has never made this problem in the past.  I felt that it would be better for me to simply ask for retraction to solve this issue, but I am a bit afraid of negative consequences in the future. Is it okay to do this? I am really interested of entering the academic world in the future. Isolate OSX Dock per Space How can I make it so that each space has its own isolated dock?  Basically what I'm looking for is:   The dock in one space should not show the icon of an app that was open in another space. If I have the same program open in two different spaces, clicking on the icon in one space should not go to the app in the other space.   Is this possible natively, or with a third party program? Copy a large data from sql query result In my sql server 2008, after running the query the data return is very huge say in millions. I tried copying but it gives an exception sql memory error. Can you let us know how can i copy the entire data and paste it into excel.  I don't want to export it to txt file as the data is not getting aligned. So i want to manually copy and paste it into excel. Please let me know the solution for thhis undefined control sequence when using \addchap When I compile my thesis.tex file which is compiled fine including the \addchap, I noticed that I have used \usepackage{unnumberedtotoc}. When I want to use my thesis.tex file on another computer it says tex capacity exceeded, sorry [input stack size=5000]. When I uncomment \usepackage{unnumberedtotoc}, it says ! undefined control sequence  \addchap.  Here I have pasted all the beginning of the packages that I have used in my thesis but I still get some problems in compilation, I don't know why, but I think if I can compile this code, then I can solve the problem  :   \immediate\write18{makeindex \jobname.nlo -s nomencl.ist -o \jobname.nls} \documentclass[12pt]{report} \DeclareMathSizes{12}{30}{16}{12} \usepackage[utf8]{inputenc} \usepackage{graphicx} \usepackage{lineno} \usepackage{amsmath}  \usepackage{array, nccmath}  \usepackage[nottoc]{tocbibind} \newcolumntype{L}{&gt;{$}l&lt;{$}} \newcolumntype{m}{&gt;{\displaystyle}l} \usepackage{framed} \usepackage{cclicenses} \usepackage{makecell} \usepackage[french]{babel} \usepackage{setspace} \usepackage{mathptmx}  \usepackage{multirow}  \usepackage{gensymb}  \usepackage{empheq}   \usepackage{mathtools}   \usepackage{array}   \renewcommand{\arraystretch}{1.9}   \newcolumntype{P}{&gt;{\centering\arraybackslash$}p{1.6em}&lt;{$}}   \newcolumntype{C}{&gt;{\centering\arraybackslash$}c&lt;{$}}   \usepackage{makecell}   \usepackage{booktabs}   \usepackage{subcaption}   \usepackage[intoc]{nomencl}   \makenomenclature   \setcounter{secnumdepth}{4}   \setcounter{tocdepth}{4}   \usepackage[justification=centering]{caption}    \usepackage{etoolbox}     \usepackage{unnumberedtotoc} %https://github.com/johannesbottcher/unnumberedtotoc/     \usepackage[automark,     plainheadsepline,     headsepline,     plainfootsepline,      footsepline,     markcase=ignoreupper]{scrlayer-scrpage}    \clearpairofpagestyles    \ihead*{\leftmark}    \cfoot*{\pagemark}    \setkomafont{pageheadfoot}{\scshape}    \usepackage{titlesec}    \graphicspath{{imagesthesis/}}    \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}    % this alters "before" spacing (the second length argument) to 0    \titlespacing*{\chapter}{0pt}{0pt}{20pt}    %\patchcmd{\@makechapterhead}{\vspace*{20\p@}}{}{}{}% Removes space above \chapter head    %\patchcmd{\@makeschapterhead}{\vspace*{20\p@}}{}{}{}% Removes space above \chapter* head    \makeatother    \title {itle 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{subcaption}  \usepackage{caption}  \usepackage{framed}    \usepackage{nomencl}   \setlength{\nomitemsep}{-\parskip}\usepackage{booktabs,multirow}  \renewcommand{\cellset}{\renewcommand{\arraystretch}{0.5}}   \begin{document}  \renewcommand\arraystretch{0.8} %\noindent  \doublespacing  \maketitle  \tableofcontents %\listoffigures  \addchap{Publications et communications}   \section*{$\:$  a. Publications:}  \section*{$\:$  b. Communications:}  \addchap{Remerciements}  \end{document} I seem to have run into a bit of a challenge on one of our Android/Samsung devices...   On the device, regardless of what's open, when the battery reaches 25% on discharge, the below screen pops up and covers the entire screen, with MUCH difficulty to get rid of. I've tried to trace it to a certain app, but was unsuccessful in doing so.     Can someone perhaps help with some advice on this, on how to get rid of it? Are the Night's Watch still required? With arrays, why is it the case that a[5] == 5[a]? As Joel points out in , in  (aka: K &amp; R), there is mention of this property of arrays in C: a[5] == 5[a]  Joel says that it's because of pointer arithmetic but I still don't understand. Why does a[5] == 5[a]? Evaluation of $ \sum_{k=0}^n \cos k\theta $ I just wanted to evaluate  $$ \sum_{k=0}^n \cos k\theta $$  and I know that it should give  $$  \cos\left(\frac{n\theta}{2}\right)\frac{\sin\left(\frac{(n+1)\theta}{2}\right)}{\sin(\theta / 2)}   $$  I tried to start by writing the sum as  $$ 1 + \cos\theta + \cos 2\theta + \cdots  + \cos n\theta $$  and expand each cosine by its series representation. But this soon looked not very helpful so I need some clue about how this partial sum is calculated more efficiently ... I am working on a game and would like to include a few jump scares. So here is a rather simple question — What makes a good jump scare and when and how should they happen? I added a new field on Opportunity table to keep a count of records, as well as track the updates made on that record.  This is needed for an external system we use. Opportinity table already has around 5000 records now. I would like to update the new field that I added with some sequence order initially. Say each record to have a unique sequence number like 1,2,3 etc(can't use the Id field for unique). The field "Identifier__c" was added for this purpose with data type number and unique contraint. For that I created a temporary class and trigger. But it is throwing the error.     Review all error messages below to correct your data. Apex trigger OpportunitySAPIdentifierHandler caused an unexpected exception,   contact your administrator: OpportunitySAPIdentifierHandler: execution   of BeforeUpdate caused by: System.DmlException: Update failed. First   exception on row 0 with id 006E00000038FPSIA2; first error:   CANNOT_INSERT_UPDATE_ACTIVATE_ENTITY, OpportunitySAPIdentifierHandler:   execution of BeforeUpdate caused by: System.DmlException: Update   failed. First exception on row 0 with id 006E00000038FPTIA2; first   error: CANNOT_INSERT_UPDATE_ACTIVATE_ENTITY,   OpportunitySAPIdentifierHandler: execution of BeforeUpdate caused by:   System.DmlException: Update failed. First exception on row 0 with id   006E00000038FPSIA2; first error: SELF_REFERENCE_FROM_TRIGGER, Object   (id = 006E00000038FPS) is currently in trigger   OpportunitySAPIdentifierHandler, therefore it cannot recursively   update itself: [] Class.AutoNumber.OpportunityAutoNumber: line 76,   column 1 Trigger.OpportunitySAPIdentifierHandler: line 4, column 1: []   Class.AutoNumber.OpportunityAutoNumber: line 76, column 1   Trigger.OpportunitySAPIdentifierHandler: line 4, column 1: []:   Class.AutoNumber.OpportunityAutoNumber: line 76, column 1   Below is the trigger and class used.  trigger Opportuniwith sIdentifierHandler on Opportunity (before insert,before update) {          If(Trigger.isInsert || Trigger.isUpdate){             AutoNumber.OpportunityAutoNumber(Trigger.new);         }   }   The class is   public with sharing class AutoNumber {       public static void OpportunityAutoNumber (List&lt;Opportunity&gt; Opp) {          if(Trigger.isUpdate || Trigger.isInsert) {              for(Opportunity p: Opp) {                  List&lt;Opportunity&gt; oppList = new List&lt;Opportunity&gt;();                 oppList = [SELECT Id, createdDate, Identifier__c FROM Opportunity where Identifier__c = null and Id != :p.Id limit 100 FOR update];                 for (Opportunity oppL: oppList) {                      if(oppL.Identifier__c == null) {                          List&lt;Opportunity&gt; OpportunityList = new List&lt;Opportunity&gt;([select Identifier__c from Opportunity where Identifier__c != null order by Identifier__c desc limit 1]);                          if (!OpportunityList.isEmpty()) {                               Decimal maxval = OpportunityList.get(0).Identifier__c;                             oppL.Identifier__c = maxval + 1;                             update oppL;                         }                      }                     // integer currentCounter = Integer.valueOf(opp.Identifier__c);                     // oppr.Identifier__c = currentCounter + 1;                     // update oppr;                 }             }         }        }  } Does $\sum \limits_{n=1}^\infty\frac{\sin n}{n}(1+\frac{1}{2}+\cdots+\frac{1}{n})$ converge (absolutely)? I've had no luck with this one. None of the convergence tests pop into mind.  I tried looking at it in this form $\sum \sin n\frac{1+\frac{1}{2}+\cdots+\frac{1}{n}}{n}$ and apply Dirichlets test. I know that $\frac{1+\frac{1}{2}+\cdots+\frac{1}{n}}{n} \to 0$ but not sure if it's decreasing.  Regarding absolute convergence, I tried:  $$|\sin n\frac{1+\frac{1}{2}+\cdots+\frac{1}{n}}{n}|\geq \sin^2 n\frac{1+\frac{1}{2}+\cdots+\frac{1}{n}}{n}=$$  $$=\frac{1}{2}\frac{1+\frac{1}{2}+\cdots+\frac{1}{n}}{n}-\frac{1}{2}\cos 2n\frac{1+\frac{1}{2}+\cdots+\frac{1}{n}}{n}$$  But again I'm stuck with $\cos 2n\frac{1+\frac{1}{2}+\cdots+\frac{1}{n}}{n}$. Assuming it converges then I've shown that $\sum \sin n\frac{1+\frac{1}{2}+\cdots+\frac{1}{n}}{n}$ doesn't converge absolutely.