I am trying to prove that the metric space $(\mathbb{R}, d(x,y))$, $d(x, y) = \frac{|x-y|}{1+|x-y|}$ is complete. To do this, I need to show that any Cauchy sequence converges. The definition of Cauchy sequence: A sequence $\{x_i\}$ is called a Cauchy sequence if $\forall \epsilon > 0 \exists N(\epsilon) : \forall m, n > N(\epsilon) => d(x_m, x_n) < \epsilon$. But I don't understand how this can be applied to a given metric space. Can anyone help?


How can I get iMessage to verify my phone number?

iMessage won't verify my phone number. When I try to select my number for messages to be sent, it's greyed out. So I receive my iMessages over email which I don't want to do.   I've tried: turning iMessage on and off, resetting network settings, rebooting my phone and nothing's worked.   Any ideas?


Why did the Elvish Rings of Power lose their power?

The  of the 3 elvish rings,     Their existence was hidden from Sauron, so they were untouched by his evil.   ,     After the destruction of the One Ring and the defeat of Sauron, [Nenya's] power faded along with the other Rings of Power.   The first quote states that they are not connected. The second states that they are connected. If the 3 rings were distinct and untainted by Sauron and his ring, why would their power fade after the destruction of the One Ring?


LaTeX: Figure environment not honouring pre-defined placement parameter

I'm working on a macro to help me inserting figures into my document with configurable placement. I'm using the pgfkeys package for parsing key=value parameters passed to that macro, one of them being the placement parameter:  \documentclass{article}  \usepackage{float} \usepackage[demo]{graphicx} \usepackage{lipsum} \usepackage{pgfkeys}  \pgfkeys{     /fig/.is family, /fig,     default/.style = {         pos =,     },     pos/.estore in = \figPos, }  \newcommand\mymacro[2][]{     \pgfkeys{/fig, default, #1}     {\em Placement parameter is: \figPos}     \begin{figure}[\figPos]         \includegraphics{#2}     \end{figure} }  \begin{document}  \section{Working as expected}  \lipsum[1]  \begin{figure}[t] \includegraphics{image.jpg} \end{figure}%  \lipsum[2]  \lipsum[3]  \section{Not working as expected}  \lipsum[1]  \mymacro[pos=t]{image.jpg}  \lipsum[2]  \lipsum[3]  \end{document}   When using the figure environment directly, the image gets positioned as expected, i.e. at the top of the page. However, when using the macro, the image gets included somewhere near the end of the document instead of close to its definition -- as though I had supplied an invalid placement parameter.  Any ideas and/or workarounds?


I was just looking through the itertools documentation, looking for a way to get rid of a nested for loop like this:  for a in b:     for c in b:         <statement>   However, I couldn't find anything. Is there not a function for this? Should I just keep the nested loops?


Let $A = \begin{bmatrix} a & b \\ c & d \end{bmatrix}$ be a $2 \times 2$ matrix with integer entries and $det(A) = \pm 1$. Consider the toral automorphism defined on 2-torus $f_A : T^2 \to T^2$, $$f_A (x, y) = (a x + b y \;\text{mod}\;1, c x + d y \;\text{mod}\; 1).$$ I don't understand what does it mean $a x + b y \;\text{mod}\;1$ and $c x + d y \;\text{mod}\; 1$. Can someone explain me?


Plural or Singular? "There are no books."

This is really just for fun. Why is this grammatically correct? "There are no books".  "No books" means a zero quantity of books which is singular per definition of plural (2 or more). So isn't it incorrect and we should instead use:  "There is no book."  As per the comment below saying that I invent the definition.  (Of a word or form) denoting more than one, or (in languages with dual number) more than two:   a word or form that expresses more than one   relating to a form of a word that refers to more than one person or thing


How to open multiple Mintty windows in Windows 8?

When I click Mintty's shortcut, it opens, if I click it again, it just returns focus to the window it had opened earlier. This is the shortcut's command I am using (I came to use it because it avoids a short wait before Mintty starts up as compared to mintty.exe -):  C:\cygwin64\bin\mintty.exe /bin/sh -lc 'exec bash'   How do I have the start shortcut for Mintty open another window instead of bringing focus to the old one?  I am using Windows 8.  Note: if I just enter the above command in Run or cmd it works fine – I can open multiple windows.


How can I compile & run assembly in Ubuntu 18.04?

So recently I've wanted to learn assembly, so I learnt a bit. I put this into nano and saved it as playground.asm. Now I'm wondering, how do I compile and run it? I've already searched everywhere and still cant find it. I'm really curious and there's no point learning a language if you can't even use it.


page suggests that we use much with only uncountable nouns whereas the use of many/several is limited to countable nouns only. So I conclude that money is uncountable noun as I've heard people saying phrases like      So much money!   But, We do count the money in our daily life then why is it that money is considered an uncountable noun instead of countable? What if I say      I have $500 to spend   Wouldn't the money be considered countable in this case?  Edit The question may be considered duplicate of the suggested question but, in my opinion, the question on that link itself is not answered properly.


I'm trying to compare the performance between the matching with precompiled pattern and a normal matching with regex using the following code. I use JUnit for benchmark testing and it looks like the nonPrecompiled code works faster.  Any ideas why? Do I run the tests in the correct way?  Class code:  import java.util.regex.Pattern;  public class StringSplitter {     private Pattern spacesPattern;     private static final String REGEX_STRING = "\\s+";      public StringSplitter() {         this.spacesPattern = Pattern.compile(REGEX_STRING);     }      public String[] nonPrecompiledTest(String bigS) {         return bigS.split(REGEX_STRING);      }      public String[] precompiledTest(String bigS) {         return this.spacesPattern.split(bigS);      }  }   And the tests code:  import org.junit.BeforeClass; import org.junit.Test; import com.carrotsearch.junitbenchmarks.AbstractBenchmark;  public class PatternBenchmarkTest extends AbstractBenchmark {      private static String bigS;     private static StringSplitter pt;      @BeforeClass     public static void prepare() {         char[] bigString = new char[10000000];         for (int i = 0; i < bigString.length; i = i + 2) {             bigString[i] = 'a';             bigString[i + 1] = ' ';         }         bigS = new String(bigString);         System.out.println("Created big string");          pt = new StringSplitter();         System.out.println("Created test class");     }      @Test     public void testNonPrecompiled() {             pt.nonPrecompiledTest(bigS);     }      @Test     public void testPrecompiled() {             pt.precompiledTest(bigS);     } }   And I get the following result:  Created big string Created test class PatternBenchmarkTest.testPrecompiled: [measured 10 out of 15 rounds, threads: 1 (sequential)]  round: 0.33 [+- 0.04], round.block: 0.00 [+- 0.00], round.gc: 0.00 [+- 0.00], GC.calls: 9, GC.time: 0.76, time.total: 8.83, time.warmup: 5.56, time.bench: 3.27 PatternBenchmarkTest.testNonPrecompiled: [measured 10 out of 15 rounds, threads: 1 (sequential)]  round: 0.28 [+- 0.04], round.block: 0.00 [+- 0.00], round.gc: 0.00 [+- 0.00], GC.calls: 5, GC.time: 0.27, time.total: 4.37, time.warmup: 1.56, time.bench: 2.82


Can I use Minecraft on a different computer than the one I bought it on?

If I buy Minecraft on my laptop and I’m getting a new one at the end of the year can I get Minecraft on the new one I’m gonna get? I’ve seen people say this works but other people say it won't. I really want to play but I don't know if I’m going to have to buy it again and waste money?


Is there a non-parametric equivalent of factorial MANOVA (at least 2x2)?

I have searched far and wide for a non-parametric test for the 2x2 between subjects MANOVA I would like to do. So far I have found non-parametric equivalents for factorial ANOVA with corresponding R packages (). Does anyone have any ideas on how to do the same analysis, but with multiple DVs?


What is the best way to consolidate two iPhoto libraries into one library?

On the family's iMac my wife and daughter have separate user accounts, each with their own iPhoto library. My wife has asked me to consolidate both libraries into a single library for convenience.  What is the best way to do this? Can it be done with the existing software and utilities that come with Snow Leopard or is there a 3rd party utility that facilitates the process?  Thanks in advance.


How to use gnome on top of Ubuntu without having to switch to Ubuntu Gnome

Quick question:  I have so many things configured in my Ubuntu 16.10 machine. IDEs, emacs,configuration files, zh, keybindings, touchpad configuration, etc etc etc.  I want to try Gnome 3, but I don't want to install a new OS (Ubuntu Gnome), is there anyway to just install gnome de, in a stable way?  Or, a way to pack and unpack all my OS configuration and programs into a new distribution? (If I really had to change from Ubuntu to Ubuntu Gnome?)


Bootstrap - fill remaining vertical space

I'm trying to design this layout using bootstrap. I put logo and navbar but now I have to insert the remaining div. I need to extend this div (with the question mark) to the remaining space of the page (with margin like the picture). I don't know logo or navbar percentage height.      Edit: Post my code (source page of Yii Framework)

         <button class="navbar-toggle btn btn-default" data-toggle="collapse" data-target="#yii_booster_collapse_yw0" id="yw1" name="yt0" type="button">                                                </button>

                     Home

                     Profile

                     Options

                             Contact Us

                             Change password

      fill vertical space
   I need to fill remaining space, not logo/brand problem.


How can we find all the files under a directory whose contents contain any of several strings?

I was wondering how to find all the files under a directory whose contents contain any of several strings  word1, word2, word3, ...? Thanks.


Where did the use of the conjunction "So,..." at the beginning of a reply come from?

I am hearing more incidences of people being asked a direct question responding with a reply beginning with  So, ...  For example,  Questioner: "What do you think we should buy Janice for her birthday present?" Respondent: "So, I thought that a voucher towards the cost of a meal for 2 at an expensive restaurant would be good, but with the Covid lockdown, I don't know when she would get any use out of it."  When, where and how did this enter into the English Language?


"An error occurred submitting the post" while editing a new tag

I created the tag proxybroker on Stack Overflow and then tried to add the excerpt and description, but I got:     An error occurred submitting the post   while trying to Save Edits.  I also tried removing the description, but it isn't working either.


Is there a Python module for converting wiki markup to other languages (e.g. HTML)?  A similar question was asked here, , but no Python modules are mentioned.  Just curious. :) Cheers.


How to fix "macOS needs to repair your library to run applications" after High Sierra upgrade?

After upgrading to High Sierra, I'm getting this error message about 30-50 times a day:    Is there any way to find out what is causing this error?  Any ideas how to fix it?


'Me' vs 'my' [pronunciation] in British English

I noticed that British people sometimes use me instead of my. For example, Liam Gallagher does it quite often. Example:  The wind was strong I have nearly lost me pants  What is a story behind this alteration? Is it appropriate in formal language? Do people really speak like that? Or is this a dialect rather than a widely spread manner?


As the temperature increases,the resistivity of conductor also increases why?

As the temperature increases, the resistivity of conductor also increases why?


Deleting C:\Windows\Installer\ files safely on Windows 7 after running WinDirStat hard drive space usage report

Has anyone successfully deleted the Windows Installer files successfully before? They are taking up 35.1% of my total hard drive space.  Which ones are needed and which ones can be purged?  In order to see this folder, I had to unhide system files by going to Windows Explorer > Organize (dropdown) > Folder and Search Options > view tab > uncheck ==> Hide protected operating system files (Recommended).  I used WinDirStat program to get these percentages. To see the image in full size, open it in a new tab.  I was told by someone that you should not delete these files, but then I found a utility--Windows Installer CleanUp Utility (very old version) that deleted these.  But it doesn't run on Windows 7.  If anyone has a later version that they found works, please let me know the path.


If several redirections are used together, does changing their order make difference?  How shall one understand the meaning of their order? Is the chained channel of redirections built as reading the redirections from left to right, or from right to left?  For example  command 2>&1 > somefile  command > somefile 2>&1   Thanks and regards!


I wanted to make a command that outputs a number in math mode. This is how my file looks like:  \documentclass{scrartcl}  %\usepackage{epsdice} %\newcommand{dice}[1]{\epsdice{#1}}  \newcommand{dice}[1]{\ensuremath{#1}}  \begin{document} Lorem ipsum... \end{document}   But when I compile this with XeTeX, I always get this error:  ! LaTeX Error: Missing \begin{document}.  See the LaTeX manual or LaTeX Companion for explanation. Type  H <return>  for immediate help.  ...                                                l.13 \newcommand{dice}[1]{\ensuremath{#1}}   I have not that much experience with TeX, I think the solution is quite easy.


Can a disagreement button and comment be allowed in audit tests?

The audit process seems very one-way....I'm not sure who decides whether one question/comment is good or bad or even the selection of question/answers for audit but I think that I am not alone in thinking that some of these calls are different than I might make and have some good rationale.  There is no way to make comments on the specific selections that would cycle back to the deciders/selectors so that the audit selection/review criteria could be improved.  I suggest that reviews be allowed to comment on the deciders' selection.  Maybe implementation of a button allowing a person to comment on the solution.


My visa to Spain was rejected with the reason that my intention to leave the territory of the member state before the expiry of the visa could not be ascertained.  I'm 17 years old and I finished secondary school in 2017. How do I appeal it? Or what should I do?


How to align subfigures in the two column paper using minpage?

I'm usin minipage to plot subfigures. I used figuresize (8 by 6) in matplotlib for all subfigures, But when I compile then in Latex their boudries don't appear at the same position (e.g top right and bottom right figure's boundry should start from same place). I'm not sure if it is due to spacing or anything else. I tried to use centering for all subfigures but it didn't work.How can I fix this issue?  `\begin{figure*}[!htb]     \begin{minipage}{\columnwidth}         \centering         \includegraphics[width=\textwidth]{Fig14.png}     \end{minipage}%      \begin{minipage}{\columnwidth}         \centering         \includegraphics[width=\textwidth]{Fig2.png}     \end{minipage}     \begin{minipage}{\columnwidth}         \centering         \includegraphics[width=\textwidth]{Fig3.png}     \end{minipage}%     \begin{minipage}{\columnwidth}         \centering         \includegraphics[width=\textwidth]{Fig4.png}     \end{minipage}`


What is this Java syntax with a section overriding a method after the constructor?

I have found a this  with the following piece of code:   CompletableFuture<T> completable = new CompletableFuture<T>() {       @Override       public boolean cancel(boolean mayInterruptIfRunning) {           // propagate cancel to the listenable future           boolean result = listenableFuture.cancel(mayInterruptIfRunning);           super.cancel(mayInterruptIfRunning);           return result;       }   };     What does this syntax means? Is this method overriding a method in the class without extending it?


Which timezone are the platform events run with?

What does Salesforce use as the system time when running those jobs? The current system time (UTC)?  My context is that I have a job that is run every 30 minutes and it executes a task for some of my users. The User object has 4 numeric fields to represent start hour, end hour, start minute and end minute. With those fields I calculate the second in the day the job should start, and the second it should end. With those two values I can compare with the system's current second, and check if the job should run for the user or not.  Some days ago this was a scheduled class that was rescheduling itself using my user credentials ('Scheduled by Renato' and records would be marked as 'Last modified by Renato' too). Then I decided to change to platform events so they would be marked as "Last modified by Automated Process" instead (which is what I want).  Now everytime the class is run, it publishes a event, and the event trigger fires the class' code that was inside the execute block. However, the timing seems off, and users are not receiving the tasks in the correct time anymore.  To get the current second correctly, I've used this code:  Integer offset = TimeZone.getTimeZone('America/Sao_Paulo').getOffSet(DateTime.now()); Integer current_second = Util.getCurrentSecond() + (offset/1000);   Util class' method:  public static Integer getCurrentSecond() {     return Integer.valueOf((DateTime.now().hour() * 60 * 60) + (DateTime.now().minute() * 60)); }   Have I not considered something when using the Platform Events?  Edit:  I just edited my code to include a call to a service that sends a message to me through Telegram. The code ran in the platform event context, and the timing is correct. System time is UTC and São Paulo is UTC-2 (originally -3, but -2 because of Daylight Saving Time):  System second: 21960 Current second: 14760


There are a couple of weird issues with hats in chat:      Refreshing fixes it but after a period of time (normally when the tab containing the chat room hasn't been used in a while) it reoccurs again.


Prove $\;\big((p\rightarrow q) \lor (p \rightarrow r)\big) \rightarrow (q\lor r)\equiv p \lor q \lor r$ without use of a truth table.

Without using the truth table, I need to prove:  $$\big((p\rightarrow q) \lor (p \rightarrow r)\big) \rightarrow (q\lor r)\equiv p \lor r \lor q$$  Up until now, we've been using truth-tables to verify equivalences. So I'm a bit lost on where to begin without using a truth-table.


Do I need a flight ticket or a flight reservation for my UK visit visa application

Am compiling documents for my visa application and I read that I need to present go and return flight tickets to prove that I will return at the end of my visit. Then a while ago I got to know that I can just get a flight reservation with out buying the flight tickets because the visa application can be refused and you have already bought the tickets.  So l request to know which of the two , having a flight ticket or flight reservation is more compelling to the visa officer and more convenient me because I would buy a flight ticket and my application is refused


Let $A$ and B be $n\times n$ matrices over a field $F$. Then prove or disprove  $(i)\, AB$ and $BA$ have same characteristic values.  $(ii)\, AB$ and $BA $ have same characteristic polynomial.  $(iii)\, AB$ and $BA $ have same minimal polynomial.  Proof of $(i)$   Let $c$ be an eigen value of AB and v be corresponding eigen vector. Then    AB(v)=cv,    B(ABv)=B(cv),    BA(Bv)=c(Bv),   this implies $Bv$ is an eigenvector of $BA$ corr. to eigen value $c$.  But this statement holds if $Bv$ is nonzero.  What if $Bv=0$?  $(ii)$ If $A$ is invertible then ($A$ inverse)$(AB)A= BA$, i.e. $AB $ and $BA$ are similar and hence have same charateristic polynomial.   Similar proof when $B$ is invertible.  But what if both $A$ and $B$ are not invertible?  I have no idea about $(iii)$.  Please help me to complete these proofs.


null pointer exception on a realtime firebase database for login in Android Studio

I have a problem with retrieving data from firebase realtime database. It keeps giving me an error saying "java.lang.NullPointerException: Attempt to invoke virtual method 'boolean java.lang.String.equals(java.lang.Object)' on a null object reference" So this method is used to retrieve data from firebase database and log users in with their username and password. I have tried if(Accounts.getPassword() != null && password.getText() != null && Accounts.getPassword().equals(password.getText().toString())) but no luck it still gives me the error. private void isUser() {     final String userEnteredUsername = username.getText().toString().trim();     final String userEnteredPassword = password.getText().toString().trim();      DatabaseReference reff = FirebaseDatabase.getInstance().getReference("login");      Query checkUser = reff.orderByChild("username").equalTo(userEnteredUsername);      checkUser.addListenerForSingleValueEvent(new ValueEventListener() {         @Override         public void onDataChange(@NonNull DataSnapshot dataSnapshot) {                if (dataSnapshot.exists()){                  String passwordFromDB = dataSnapshot.child(userEnteredUsername).child("password").getValue(String.class);                 Accounts accounts = dataSnapshot.getValue(Accounts.class);                   if (passwordFromDB.equals(userEnteredPassword){ // ****Line that code is not working****                      String usernameFromDB = dataSnapshot.child(userEnteredUsername).child("username").getValue(String.class);                     String accountFromDB = dataSnapshot.child(userEnteredUsername).child("account").getValue(String.class);                       Intent intent = new Intent(getApplicationContext(), Driver.class);                      intent.putExtra("username", usernameFromDB);                     intent.putExtra("password", passwordFromDB);                     intent.putExtra("account", accountFromDB);                      startActivity(intent);                 }                 else {                     password.setError("Wrong Password");                     password.requestFocus();                 }             }             else {                 username.setError("Wrong username");                 username.requestFocus();             }         }         @Override         public void onCancelled(@NonNull DatabaseError error) {          }     });     }


Is there a "native" Javascript function that modifies an object property

Is there a native JavaScript function (or library/module for JavaScript) that modifies a key's value and then returns the full object?  Here's what I've done:  function modifyJSON(jsob, key, val) {     var newjsob = JSON.parse(JSON.stringify(jsob));     newjsob[key] = val;     return newjsob; }   (Of course, if I wanted to modify the original, I could delete var newjsob... and work with jsob directly.)  This works, but if this type of functionality has already been implemented somewhere, I'd prefer to use that than roll my own.


How do I remove Ubuntu's password requirement?

Here are my circumstances:   I am running Ubuntu 12.04. I have one user account.   I absolutely hate the password requirement. How do I disable this requirement such that my Linux computer will behave more like Windows in this respect? I do not want to hear that I shouldn't this because it is not secure. This is my desire so the concern of security is effectively null and void.


why equals() method when we have == operator?

When i see the implementation of equals() method it does nothing but same as what == does. So my question is what was the need to have this as separate method when we have == operator which does the same work?


Can pre-hardmode bosses spawn in hardmode?

I just killed the wall of flesh and entered hardmode in my world.  As far as I know, all of the Hardmode bosses can now spawn randomly every night - but only Hardmode bosses. However, the Eye of Cthulu spawned three nights after I killed the wall of flesh.  Can Pre-Hardmode bosses spawn too, after the Wall of Flesh has been defeated?


Does cross-validation work for this type of modelling time-series

I am new to working with time series. I have come across the statement that k-fold cross-validation is not be suitable for time-series, but I have a doubt that this restriction does not apply to my situation. My time-series are restricted to a certain interval, let's say 12 months. Furthermore assume that I have 100 samples of time series, respectively 100 sequences of values, for which I assume that they were generated by the same process. The individual samples (one sample = one series = one sequence) are incomplete, for example one sample could have missing measurements in month 1 and 6, and another sample misses measurements in months 2 and 4. I want to learn/create a model which allows me to predict the missing values of samples I haven't seen before. Naively, I would assume that I can do 5-fold cross-validation here by splitting my 100 samples into five folds of 20 samples each, train on four folds and validate on the fifth, repeating for all possible validation folds. I don't see how this could lead to data-leakage, since I do not split any one series into several parts. Rather, I treat each series as an individual sample. Am I correct in my assumption that I am doing something else than the usual 'forecasting' here, because I assume a restricted time-horizon, into which my inference falls as well? What is the name of this problem? I assume one could still say that I am forecasting in some sense, because in inference I might be confronted with a series which misses data for all but the first month. Or am I missing something fundamental here and cross-validation is indeed inappropriate?


Can I ask for an earlier UK visa start date?

I just received my UK visa and the start date is August 8th. I actually stated that my travel date would be in August because I was under the impression that the visa application needs to be made 2-3 months before intended travel. Based on my current schedule and my family availability (in the UK) July is a more favorable time to travel.   Can I ask for a change of date? Is this worth the trouble? And what would be the specific process of achieving this change? I currently live in the USA but I am not a US citizen, I am Ghanaian.


'Articulate' badge for perfect presentation

I propose the Articulate badge, to be awarded for posting [n] questions which   remain up for [given amount of time]  receive no edits  receive at least one up-vote  receive at least one answer with an up-vote   Basically, a reward for perfect presentation.  This will encourage well-crafted questions, which are valuable because:   They help the poster to . They elicit .   Negatively, this could promote spurious editing with the malicious goal of preventing someone else from receiving the award.  Spurious editing is actively discouraged so perhaps we're safe.


I have a image of width:300px, height:400px;  My container size is  width:168px, height:208px;  I want to display only a part of the image so that it can fill the container.   like:  Suppose top left corner is 0px 0px bottom right corner is 300px 400px of the original image.  I want to display picture from 10px 0px(top-left) to 200px 208px(bottom-right) such that it fits in the container.   How to do this in css?


Are we creating too many different Stack Exchange sites?

I was just thinking that maybe if we have more Stack Exchange websites then each person would be a member of more different sites on average. Since the time a person can spend online on average is limited it means he will be spending less time on each website. But would this affect the quality of these websites? I'm not talking only about the quality answers given but also the number of answers given, the promptness. Won't these things go down?  I think that the rate of questions won't go down much because you need to know what you need to know. However, the average time a person spends browsing through these websites (and chances upon a question he can answer) would decrease. So are we creating too many different Stack Exchange sites?


Boot Camp Fails to Save Windows Support Files

So I'm running macOS 10.14.5 on a 2012 Macbook Pro.  I just put an SSD into the system to replace the internal spinning drive and reinstalled a new copy of the OS from scratch then did the migration assistant using the old drive to copy new data over.  I'm trying to use Boot Camp Assistant to install Windows 10, which I had done previously on the spinning drive.  I did not, however, save the Windows Support files from my previous installation of Windows 10 and need to redownload them.  I try to do this, but every time I do the system says that it cannot save the files to the USB drive (which is an 8Gb drive that is empty and freshly formatted to FAT / MBR).  I've reset my SMC and NVRAM (though I'm not sure how that would help) and reformatted the drive a number of times, to no avail.  The system seems incapable of getting the Windows Support Files.  Is there an alternative method of downloading the files?  The computer seems to download the files (which previously as a DMG stored in /Library/Application Support/BootCamp, but during the download and attempt to write the files to the USB drive, the DMG never appears.  I checked for open files lsof -p [PID of BCA] and it shows that it's writing to a bunch of .data files in the /private/var/... tree.  I'm not sure how to unpack these into the actual data and have no idea what format they are in.  Is there any kind of alternative way to download the files?  I did try to use BCA in safe mode but it wouldn't mound the FAT partition on the USB drive at all, so that was a bust.


I am quite new to Ubuntu and I am trying to install node.js on 12.04.  I have the source code in a tar.gz.  I am not sure what I need to do with this file.  I guess I need to extract it but is there a recommended place I extract it too?  Also after extracting it should I just be able to use it from the command line or do I need to do anything else?


How to specify the null hypothesis in hypothesis testing

What is a good rule of thumb for how to choose the question for the null hypothesis. For instance, if I want to check if the hypothesis B is true, should I use B as the null, B as the alternative hypothesis, or NOT B as the null? I hope the question is clear. I know that it has something to do with the error I want to minimize (Type I?), but I keep forgetting how it goes, because I don't have a clear intuition built for it. Thanks.


I'm trying to check if an elements already exists in an array. I know of at least 2 different ways to do so:   and .  I tested both of them, but get no in both cases:  var myArray = ["Banana", "Orange", "Apple", "Mango"];  if ("Banana" in myArray) {   console.log("yes") } else {   console.log("no") // <-- }  if (typeof myArray["Banana"] === 'undefined') {   console.log("no") // <-- } else {   console.log("yes") }   In both cases I get no. Am I missing something?  Also, which of them is faster?  .


Clustering procedure where each cluster has an equal number of points?

I have some points $X=\{x_1,...,x_n\}$ in $R^p$, and I want to cluster the points so that:   Each cluster contains an equal number of elements of $X$. (Assume that the number of clusters divides $n$.) Each cluster is "spatially cohesive" in some sense, like the clusters from $k$-means.   It's easy to think of a lot of clustering procedures that satisfy one or the other of these, but does anyone know of a way to get both at once?


I have a question: how do I use rolling window forecasts in R:  I have 2 datasets:    monthly data which I downloaded from Google.  monthly data I downloaded from the CBS (central bureau of statistics in Holland)   I want to test whether I can build a valid forecasting model, based on say 6years of Google Data, by using rolling window forecasts.  My first intuition was to fit an ARIMA model on the Google Data and test this model on the actual CBS data by calculating the RMSE. But this is not efficient since I need to do this for every month, and I have a lot of months to analyse.   Is there an automated way in R to do this?


Calling the UI Api from a community with a custom domain name - getting sun.validator exception

Context: we're using the UI api to get some Record Type dependent picklist values back.  This is happening in a community context.  In the lower environments (dev, QA) this works without issue.  The remote site settings seem to be fine and we get the values back.  Problem: In production, which uses a custom domain name for the community, we're running into trouble and getting this error when the call is made:  System.HttpRequest retrying request in response to handshake failure: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target   From what I'm seeing, the url of the REST request is formed using the custom domain name in the prod environment, but uses the normal salesforce community domain name in the lower environments.  The remote site settings appear to be similarly configured.  It does appear we have a self-signed certificate in place that doesn't expire until 2020, but I'm wondering if there needs to be some other change to accomodate the custom domain name?  edit: this is calling Salesforce UI API from a Sales Cloud hosted domain.  Not a batch process calling an outbound api.


2 Windows 8 Loaders appearing at the grub menu

So, after an install of Xubuntu, my grub loader has 3 things, Xubuntu and then 2 Windows 8 Loaders How can I fix this?


Probability that numbers 1...6 show up at least once when rolling 8 dice  How can this be solved using the inclusion-exclusion principle.


How can I find out if Ubuntu supports a particular hardware component, that is, if it works in Ubuntu?  I am going to put together a computer and I am choosing components.   How do I know if Ubuntu supports this or that motherboard, or this or that sound card, or this or that graphics card, etc? How do I know that there is no conflict in Ubuntu between this and that hardware component?   What resources are there to help with such situations?  I know that there are computers with Ubuntu pre-installed and that there are  for whole computers but this is not what I'm looking for. I'm looking for resources to find out support for particular hardware components and conflicts among particular hardware components.


I want to know what kind of power supply I have and what wattage it has. I tried:    sudo dmidecode -t 39   but that didn't show any specs. What do I need to do? I am on Ubuntu 13.10


Prove to Yahoo and Bing that you are the original author

Yandex (the main Russian search engine) has a form where you can submit text here:   If the text does not exist already, then yandex will treat this text as if it belongs to you. Our website, which produces weekly original content regularly uses this service.    How do you achieve the same thing in Yahoo and Bing?  ()  P.S. It does not need to appear at the top of SERPs, as long as the system somehow knows the author.


I'm trying to pretty up my order list items and I'm now wondering how I can achieve the following effect, and if it's even possible in pure CSS:    Is it possible to change the number-points and style them like this in just CSS, and if so, how?


What can I do in Hong Kong with a three hour layover?

I was wondering if there was anything I can do in Hong Kong for a small amount of time, aside from just hanging around in the airport.   Are there nearby places reachable within 30~ minutes of transport or less? Street food, parks, or anything at all?


The number $2^{29}$ has $9$ distinct digits. Find the missing digit without the use of a calculator.

$2^{29}$ has $9$ distinct digits. Find the missing digit without the use of a calculator.   I've seen its solution before but I still don't understand it. Math novice here. A detailed answer will be appreciated. Thanks


What are all the correct answers to the Squirrel's questions, and what is the reward when I get them all correct?

I encountered The Squirrel at "A tree."              |   |                                                                         |   |                     "   Hello, I'm The                        |             |                        Squirrel. I can                        |             |                      provide you candies,                     |             |                      and lots of things.                                    |                      I know how much you                                    |        _.-'''-,      love candies. But I                                    |      .'        `\     feel alone in this                                    |     /           /          forest.       "                         |        |    /      .--^_^                                                   |        |    |     /  C ,,\                                                           |    |    |   \  _.)                           ___                            |     \   |   /  \                   ____.----'.-'                            |      '-, \./ \)\)               .-' --  __.-'                   |            \        `-/   );/           ___/  - _.-'                        |             \_________''--'-'________.-' --    /                            |              -   --        -  -     -     __.-'                                              -    --    -     --   --  /                                                 _________________________.-'                                 He asks you some questions. What are the correct answers, and what is the reward for getting them correct?


How can i shorten long multiple checking variable in bash?

i want to check multiple variables in bash but end up too much, is there any way to shorten this i end up like this if [[ $1 == -a || $2 == -a || $3 = -a ]] && [[ $1 == -b || $2 == -b || $3 = -b ]] && [[ $1 == -c || $2 == -c || $3 = -c ]] && [ $# -eq 4 ]; then echo "insert some words" exit fi  i've tried this to shorten it but won't work a=-a b=-b c=-c if [[ ${@:1:3} == $a || ${@:1:3} == $b || ${@:1:3} == $c ]] && [ $# -eq 4 ]; then echo "insert some words" exit fi  is there any way to shorten this? thanks in advance!


What do I need to know to get started as a professional UX/interaction designer?

I am a student of Software Engineering (mainly focusing on Requirements Engineering). I am a beginner in the field of UX. There already are a few questions on this forum regarding books etc. Still, I feel my question is a little different:  What qualifications are required to be a UX Professional/ Interaction Designer? What tools do you need to know? What can you do on your own to be proficient in this field? Because I don't have any formal training in this field and I can only learn things on my own.


$f_n:[0,1]\to [0,1]$ continuous, $f_n\to f$ uniformly, prove: ${\frac1n}\sum_{k=1}^{n}{f_k} \to f$ uniformly

I was able to prove, hopefully correctly, that the sum converges uniformly. But, I'm not sure how to show it converges uniformly specifically to $f$.  The way I proved it converges uniformly was by using the Dirichlet convergence test, by taking $a_k(x) = \frac1n$ and $b_k(x) = f_k(x)$. $\sum_{k=1}^n{b_k(x)}$ is uniformly bounded on $[0,1]$ by $n+2$ for instance, and $a_n$ is monotone and uniformly convergent to 0 because it does not depend on the value of $x$.  I got rather stuck after this. I guess I have to use the continuity of the functions and the uniform convergence of both, but I can't figure out how to show that they converge to the same thing. Any help will be greatly appreciated.


The input value of TextField is equal to the array list value, but the value won't be reported. why?

Email that I enter in TextField in this section of code is exactly equal to the email in one of the accounts in the array list, but every no has is true. Where is the problem??   boolean has = false;             for (Account value : accounts) {                 if (value.email == email.getText().trim() && value.password == password.getText().trim()) {                     has = true;                 }             }


Area51 statistics page for Islam.SE is not showing any avid users

It would seem that  is not showing any avid users:    I am guessing that this is a bug so I am here reporting it.


Semicolon Usage in Sequential List (Only One Element Comma-Separated)

Broadly, the steps involved in establishing a full implementation can be separated as follows: analysing the application to be accelerated; understanding the logic, compute, and data dependencies; and then enabling this on a chip given the constraints of real hardware.   Is this correct usage of semicolons? I'm not concerned about them following the colon; I'm only concerned about using it in a list where only one individual element - as far as the semicolons are concerned - is itself comma-separated. Also slightly concerned about how the list being sequential affects the sentence flow.   Many thanks in advance for any help/advice.


Following the instructions at tutorials.ubuntu.com I created a bootable USB stick running Ubuntu 16.04.4. It boots and runs Ubuntu fine but I can't save any files. I made a few test files and saved them to Documents. But the next time I booted from the stick the files were not there. It was like the first time the stick had been used. Also the network settings such as Wifi network and password were not saved. Is there a way save files and setting changes to a USB stick? Or do I have to be using regular HD? Thnaks


PATH is not affected by .pam_environment

Running Ubuntu 13.04, I'm trying to add variables to PATH for the session, which is , but nothing seems to work. Here's what it looks like:  JAVA_HOME          DEFAULT=/usr/lib/jvm/java-7-oracle IDEA_HOME          DEFAULT=/usr/local/idea-IU-129.451/bin LIGHTTABLE_HOME    DEFAULT=/usr/local/LightTable CLOUDIFY_HOME      DEFAULT=/home/eliranm/builds/gigaspaces-cloudify PATH               DEFAULT=${PATH}    OVERRIDE=${PATH}:${JAVA_HOME}:${IDEA_HOME}:${LIGHTTABLE_HOME}:${CLOUDIFY_HOME}   It seems all variables are set but the PATH, or that it is overridden somehow. I tried to prepend or append the ${PATH} variable, to use DEFAULT only, OVERRIDE only, tried to just set a hard-coded path as a value, all to no avail.  I'm following the recommendations from the Ubuntu help community, and I want to avoid concatenating hard-coded paths to the PATH inside /etc/environment as it's not the right scope, plus, it will be hard to maintain with no variables.  Others may be affected by this issue, , but no one provided a solution so far.  How to make this work?


Auto transfer of luggage between 2 airlines till final destination

I have bought a tickets from Harare to Dubai of Rwand Air from their office.  Then I bought a ticket from Dubai to London of Emirates Air.  Both the tickets were separately from their respective offices. What should I do to ensure that my luggage reaches directly to destination, instead of me having to collect at Dubai Airport and check-in again.


Why is the p-value changing and what does it mean

I have a simple question about regression. The situation:  I have three variables $X_1,X_2,X_3$ and a variable I try to estimate $Y$. (In practice I have a list of participants for which the values of all of these variables are known) Using regression I obtain $$Y= a_0 + a_1X_1 +a_2 X_2 +a_3 X_3 +a_{1,2}X_1\cdot X_2 + a_{1,3} X_1\cdot X_3 + a_{2,3} X_2\cdot X_3 + a_{1,2,3}X_1\cdot X_2\cdot X_3$$ and I get $p$-values for each of these coefficients. I made these changes:  I decreased all the values of $Y$ by $10$ (because I wanted the values to start at zero). Then I replaced $X_1$ with $X_1-1$ ($X_1$ was the gender, and instead of $1,2$ I wanted it to be $0,1$). Finally I divided $X_2,X_3$ by $40$ to get values between $0$ to $1$. All these changes also changed the coefficieints $a_0,a_1,...$ (I understand why this is). Positive coefficients stay positive and negative stay negative. But the $p$-value changed and I do not understand why. Does the $p$-value suppose to change by making these changes? What does it mean? Basically I lack the understanding myself and I need your help to decide whether I can use the new data (for which the $p$ value is better) to conclude what I want. Thank you :)


If $AB = I$. Prove that $BA = I.$(use only linear combination/matrix multiplication)

Can anyone prove this using only linear combination/matrix multiplication ?     Let $A$ and $B$ be $2 X 2$ matrices such that $AB = I$. Prove that $BA  = I.$   $\left[\begin{matrix} a&b\\c&d \end{matrix}\right]\left[\begin{matrix} e&f\\g&h \end{matrix}\right]=\left[\begin{matrix} 1&0\\0&1 \end{matrix}\right]$ is of no use as I end up with so many unknowns  $AB=\left[\begin{matrix} A_{first row}B_{first column}&A_{first row}B_{second column}\\A_{second row}B_{first column}&A_{second row}B_{second column} \end{matrix}\right]$ is also not helping


Google taking my logo as title and description some text on the page

I made a website using nuxt.js and added title and meta description on each page. I also made a sitemap.xml and robots.txt for the site and submitted in Google search console.The issue is Google and other search engines are taking some random text on the page and title as the logo on the page. It tried different website to check what is exactly being crawled like metatags.io it is showing the correct result which I desire But still whenever I search I get this in the search result I tried to recrawl the website in the Google search console still stuck with this issue. Is there anything I am missing??


Can I convert SQL Server 2008 full db to SQL Server 2005?

Recently I converted my SQL Server 2005 database to SQL Server 2008. Now I can't attach that db to SQL Server 2005. I do not have any backup of that db file as well. I have tried to generate scripts but that way i can only recover the tables. Is there any way to convert the whole database along with existing records? Please help


How do you make normally hostile mobs not hostile?

I'm trying to make a place where nether mobs are friends but I don't know how to. How do I make a mob friendly? (I'm making the map in Creative mode.)


I am confused of all that different Quantum computers. please correct me if I say something wrong. There are two main different types of quantum computing:  Quantum Gates based computing quantum annealing  For quantum gate based computing, I know that there are different kind of architectures -- that's clear for me. But why I am so confused is, there is the Quantum Annealing, which is used by D-Wave Systems and that Q. annealer is using the adiabatic theorem , right ? So then we can say that Adiabatic Quantum Annealer = Quantum Annealer ? The next confusing term is Adiabatic Quantum Computer , is that Adiabatic Quantum Annealer? And the last is what is Quantum Simulator ? Where is that used ? which type of quantum computing are that simulated? And is there a difference between them and quantum annealing ? Too many questions :/


How do I revert to classic Google Calendar?

November, 2017: Google Calendar offered me a new look.  I tried it and would like to revert to the previous version.  I checked the help pages and read that I should click on the little gear icon and then would see "Back to classic Calendar."  But I don't have a little gear icon, and when I go to Calendar Settings, I don't see a way to return to classic calendar.


I pasted a long text in the word and the source was gone so I can't copy it again. And in a rush while closing word I forgot to hit save and wrongly clicked on don't save option. Now I have no idea if I can recover it in anyway? I copied something else in meanwhile so I can't paste it again. I tried to look for clipboard history but nothing. I am using windows 7 pro. Any help?


Why is reduction formula of $\int \cos^n (x) dx$ restricted to n>1?

$$\int\cos^n x \ dx = \frac{1}n \cos^{n-1}x \sin x + \frac{n-1}{n}\int\cos^{n-2} x \ dx$$   is valid for n>1  The derivation of the reduction formula is well-discussed on the forum , but I can't find anywhere explaining why it is only valid for n>1. Can someone explain?


How could the Fremen do what they did to the empire in Dune Messiah?

How could, and why would, the Fremen's jihad kill 61-Billion people and conquer the known universe?  Their leader Paul was already emperor.  What was left to conquer?  And how could they force this onto Paul when they had no relationship with the Spacing Guild except thru Paul?  If Paul didn't arrange for transportation then how would they get off Arrakis?  And how does a small population of hardened, rugged, but not technologically advanced people do that much conquering in that time?  Also, is there any explanation about how Ix, Tleilex planet and Bene Gesserit planets hold off the wave of jihad?


How to compute remainder of division of $P(x)$ by $x^2 -3x+2$?

The remainder of division of $P(x)$ by $x^2−1$ is $2x+1$, and the remainder of division of the same polynomial by $x^2−4$ is $x+4$. Compute the remainder of division of $P(x)$ by $x^2−3x+2$.   I will translate these into math equations  $$P(x) = (x^2-1)Q(x)+ 2x+1$$  $$P(x) = (x^2 -4)R(x)+x+4$$  And let   $$f(x) = P(x) $$  We're asked to find the remainder when this polynomial is divided by $x^2 -3x+2$. So, there are two equations, which is why I'm confused with what to use in the equation $f(x) = P(x)$. What am I missing here?  Regards


Dynamically Adding/Removing CSS in Nested Div

I'm trying to hide a div dynamically. This works for me. But when I try to do a nested div. It suddenly doesnt work anymore. Am I missing something?  Component(Working)  <ui:button label="Toggle" press="{!c.toggle}"/>
Now you see me
   Component(Not Working)  <ui:button label="Toggle" press="{!c.toggle}"/>

Now you see me

   Controller  toggle : function(component, event, helper) {         var toggleText = component.find("text");         $A.util.toggleClass(toggleText, "toggle");     },   Style  .THIS.toggle {     display: none; }


Remove ALL PRIVILEGES from an user group and Allow it to open only one program and read one directory

Hi, I need an user group to only be allowed to use gthumb and read from only one folder/partition which I will decide.  Please can you let me know how to do this?


At first I had an account in stack overflow of reputation 221. The I joined Mathematica and got the reputation of 101 in Mathematica. When I came back to stack overflow I found that my stack overflow account had also received +100 association bonus. I then decided to join Physics and received 101 in Physics but this time my stack overflow account was not given +100 . Why did this happen??


Watchmen book ending versus movie ending

So if it wasn't obvious, pretty big spoilers ahead.  At the end of the book...      Ozymandias teleports a genetically crafted alien creature into cities around the globe, killing millions in an attempt to stop the nuclear holocaust by giving the U.S. and Russia a common enemy in the aliens. He attempts to destroy Jon, but fails.  Jon leaves of his own accord in a desire to create life afterwards. Ozymandias questions his own actions momentarily.    At the end of the movie...      Ozymandias does almost the same thing, but instead uses Jon as the common enemy. Jon leaves for the greater good (and to create life). I don't think there is an attempt at destroying Jon. I also don't remember if Ozy felt unsure of his decisions.   Is there an out of universe reason the ending was so different in the movie? Did anyone say why?   explains in logical terms why the movie was different, but I'm looking for quotes from directors, writers, producers, actors, etc etc. The linked question is 4 years old and has no official quote from anyone.


If I change my display name, will the change reflect in comments?

I am interested in changing my display name to my full name, but am concerned about losing the connective tissue in the comment threads I participated in. Because @name links do not appear to be linked or coupled to an account, I want to avoid impairing the readability of a discussion.  If I were to change my display name, does the change, in turn, update @name user references for questions/answers/comments I participated in?


I long thought that in C, all variables had to be declared at the beginning of the function. I know that in C99, the rules are the same as in C++, but what are the variable declaration placement rules for C89/ANSI C?  The following code compiles successfully with gcc -std=c89 and gcc -ansi:  #include <stdio.h> int main() {     int i;     for (i = 0; i < 10; i++) {         char c = (i % 95) + 32;         printf("%i: %c\n", i, c);         char *s;         s = "some string";         puts(s);     }     return 0; }   Shouldn't the declarations of c and s cause an error in C89/ANSI mode?


How to unpack a tuple before assigning it to *args?

I have this following code:      class NumberAdder:         def adder(self, *args):             self.sum = 0             for i in args:                 self.sum += i             return self.sum      class StringAdder:         def adder(self, *args):             self.word = []             for i in list(args):                 self.word.append(i)             print(self.word)      class ThingsAdder:         def __init__(self, *args):             self.box = args         def stringAdder(self):             a = StringAdder()             a.adder(self.box)          def numberAdder(self):             a = NumberAdder()             a.adder(self.box)      c = ThingsAdder(1,2,3,4,5,6,9)     c.numberAdder()   The problem is as you can see i assign *args to another *args. What should i do to make *args in NumberAdder class receive unpacked (not in form of tuple) arguments ?


I know how to calculate residues of several functions, but I really don't know what residue is. Is there any way to really explain what residue is?


Picking a lock typically requires a DC 15 Dexterity check (Basic rules, p. 49). Likewise for manacles (p. 50), which can alternately be escaped with a DC 20 Dexterity check or broken with a DC 20 Strength check. But what happens if you fail?  The general rules for ability checks state (p. 58):     If the total equals or exceeds the DC, the ability check is a success—the creature overcomes the challenge at hand. Otherwise, it’s a failure, which means the character or monster makes no progress toward the objective or makes progress combined with a setback determined by the DM.   As a DM, how can I handle this in practice? In our last session, the players wanted to get inside a locked building to rescue people trapped inside. Picking the lock seemed like an easy enough task for the rogue, but unluckily he failed the check, and I wasn’t prepared for the consequences. There wasn’t much time pressure and no obvious reason why he couldn’t try again, so I allowed another attempt, but it just didn’t feel right.  I’m sure that similar situations will come up again, so I’d like some advice on how to deal with checks so that they don’t just turn into a tedious exercise of rolling until you succeed. I presume that  was left out of the game for good reason, but I’m not sure what to do instead. I suspect that this was a good occasion to use “progress with a setback” but that’s a fairly new thing for D&D and I’m not sure how to go about it. I’m unsure when I should use setbacks versus lack of progress, and in the latter case I’m unsure when I should allow players to try again versus requiring a different approach.  For example, suppose that a manacled player tries to pick the lock and fails the DC 15 Dexterity check. Now, the player could try to pick it again, or he could try one of the other escape methods, or he could wait for somebody else to rescue him, or he could simply succeed with some setback like a minor injury. How do I choose how to proceed? Or do I let the players choose?


How can I install a specific version of a set of Perl modules?

I'm tasked with replicating a production environment to create many test/sit environments.  One of the things I need to do is build up Perl, with all the modules which have been installed (including internal and external modules) over the years. I could just use CPAN.pm autobundle, but this will result in the test environment having much newer versions of the external modules that production has.  What is the easiest/best way to get and install (a lot of) version specific Perl modules.


what does 'y' stand for in apt-get install?

Could anyone clarify what does the sudo apt-get install -y <package> do? what exactly does the -y stand for?


What method does Gnome shell use to gracefully close all windows belonging to an application?

As shown in the screenshot (showing a modified gnome favorite bar, but still with stock functionality), when I right click an application with multiple windows open on the gnome favorites bar, I get the menu entry "Quit # windows". Clicking this closes each of the windows belonging to the application gracefully, giving the opportunity to save. Does anyone know what method gnome shell uses to accomplish this or how I could hook into this function with the command line?  I'm trying to build a hotkey that will mimic the behavior of the Command+Q hotkey on MacOS, and since the gnome favorites bar provides exactly the same functionality, I would like to use the pre-existing functionality (if at all possible) as I have been able to find or modify wmctrl and xdotool scripts and methods offered in previous threads.


Let $(X,\rho)$ be a metric space.   Is it true that $d:=\dfrac{\rho}{1+\rho}$ is also metric. If it's true can anybody give a hint how to prove the triangle inequality for $d$?


I am an undergraduate student who is majoring in physics and computer science (two majors) at Baylor University, but had a bad first semester while taking Elementary Chinese, Calculus I, General Physics I, and Introductory Chemistry I. I withdrew from Calculus I, but received a B- in physics and a C in both Chinese and Chemistry. In the summer before beginning at the university, I took Calculus I twice at a junior college during 6-week courses, receiving an F the first time and a C the second, but began it again under recommendation from the math department until realizing that I lacked the time management skills necessary to complete all the courses successfully in the first semester. After receiving an A in every class after the first semester at the university, will these first grades harm my image in the eyes of graduate school admission boards or employers? I am seeking admission with universities such as MIT and the University of Chicago for graduate school, so I would like to know what is thought about this problem.


Can a dual national use VWP with one passport when they have a valid US visa in the other (non-VWP-eligible) passport?

I have dual Bolivian/Czech Republic nationalities.  In my Bolivian passport, I have a US B1/B2 visa, which will expire in three months.  Can I apply for an ESTA and enter the US under the Visa Waiver Program (VWP) on my Czech passport, before my visa expires?  The Czech passport is a new one with the chip.


my TT2 ( template toolkit 2) causes an error due to absence of the plugin, what could be the possible cause ?  the error reads  Error 500 - Internal Server Error  plugin error - YAML: plugin not found  Powered by Dancer2 0.159001    is there any way of making the message a little clear?


Find the number of pairs of positive integers (n, k) that satisfy the equation $(n+1)^{k} -1 = n!$  My try: seeing the problem, I saw Wilson's theorem which states that $(p-1)! = p-1 mod p$. Therefore, we can let $a-1=n$, then $a^k -1 =(a-1)!$ where in A is prime, I tried a= 2, a=3, and a=5 as solutions but can't find anymore, why cant i find anymore primes?


Minecraft Windows 10 edition testfor command

In the Windows 10 edition, I'm trying to create a capture the flag (banner) map which detects if the flag has been dropped and replaces it back at that team's base but I can't manage to set up the command. So far I have tried: /testfor @e[type=Item] {Item:{id:minecraft:banner}}  to receive: Syntax Error: unexpected "{" at "ype=Item] >>{<<Item{in:m"  I know some commands are slightly different between Bedrock and Java, so I could have the wrong syntax. Also, it would be great if it could detect the colour as well. Please, could someone enlighten me? Note: It is not the same as the question:  because I want to test for a block, not setting it so you are only able to place it on specific blocks. It is also not a duplicate of  as this question was written first, therefore they have asked a duplicate of my answer!


How can a non-EU citizen living in the UK invite their friend to visit them?

We both hold Indian passports, my friend started studying a funded doctoral program in France recently, and I have applied for my Tier 4 visa to study my self-funded MSc course in the UK.   He wants to visit me in the UK to help me settle down once I go there in a few weeks. I plan to live in an Airbnb apartment for the first few days, find an apartment that I would like to live in for a year, and then have him over for a couple of days to help move my stuff and set everything up.   I understand that his application would need an invitation from me, along with a copy of my visa, proof of my student status from my university, and proof of accommodation and finance. As for accommodation, we plan to book the Airbnb apartment together. But since he has recently moved there, his bank account is new and doesn't have any balance yet, and I will still be in India while he applies for his visa.    Can I use the same (Indian) bank statements that I used for my Tier 4 visa with his application? Should I have him enclose the contract for his funded PhD and rental contract for his current apartment (managed by his university) as evidence that he will return after he's done helping me? What else could he enclose as evidence? Will he be able to use the same visa to return to the UK later, maybe in the same period while I'm still setting up and he has to return to France for some appointment, maybe afterwards, provided it's before his visa expiry date in six months?   This is not the same as  as the person asking that is a UK citizen, while his guest is being funded by the guest's family, while our case, none of us are UK citizens and are not being funded by anyone else.


Showing the existence of a certain kind of extension of a finitely generated algebra

I wanted to ask if someone had a proof for the following claim:     Given and integral domain $A$ and a finitely generated $A$-algebra $B$, show that there exists elements $x_1,...,x_n \in B$ algebraically independent over $A$ and a non-zero element $a \in A$ such that $B[\frac{1}{a}]$ is integral over $A[\frac{1}{a}][x_1,...x_n]$.   Thank you!


Will playing a game in a Android phone while charging damage or cause harm to the battery or the phone?

Will the following situation damage or cause any harm to the battery or/and the phone:   The phone is being charging (regardless it is using the electrical outlet or via USB) and .. You are playing a game while the phone is being charging and .. You will be playing the game for 5 hours or more.   In another word, if you will be playing a android game in a android phone for 5 hours or more while the android phone is being charging, will it cause any damage or harm to the android phone and/or the battery inside the android phone?


Alright so i got a brand new J7 and the first day was going fine, i waited for the battery to go to 5% and i'm charging it now. Am i supposed to let it charge to 100%? Or i can INTRERUPT (good grammar.) it at like 70% like that. I need answers fast please! Thank you!  YS JP


Easier method to prove limit by epsilon delta definition.

supposed I wish to prove this limit via the epsilon delta definition of limits:  $$\lim_{x \to -1}\frac{1}{\sqrt{x^2+3}}=\frac{1}{2}.$$  This means I have to show that:  $$\bigg|\frac{1}{\sqrt{x^2+3}} - \frac{1}{2}\bigg| < \epsilon$$  whenever $0<\big|x +1\big|<\delta$.  How can I proceed to choose $\delta$ in a way such that my proof will be simple? So far I have tried to work "backwards" but ended up all messy because of the squareroot.  Any hint or help would be appreciated. Thanks!


Tri-state checkbox: Which state should be selected after clicking?

There is a hierarchy of selectable items, let's say a parent and two children. All three items have checkboxes. When both children are checked, the parent's checkbox is also checked. When both children are unchecked, the parent's checkbox is also clear. When only one of the children is checked, the parent is half-checked (color fill or a diagonal inside the checkbox).  This relationship works both ways - the parent's checkbox works as a select/clear all for the children checkboxes.  What should happen when users click the half-checked parent - check or uncheck? Or rather, what factors might influence this decision?


How to find 'URL' and append something at the end of URL

In Data Extension one field 'HTML' have Data that I have shown below, Now I have to Find the 'Href', and and at the last of URL append some text like '&MC='. It may have Multiple 'Href'. Please help me on this.

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If integral is zero and function is continuous and non negative, then what about the function?

If $f$ is continuous on $[a,b]$, $f(x)≥0$ on $[a,b]$ and $$\int_{a}^{b} f(x) =0$$   then prove that $f(x)=0$ for all $x \in [a,b]$.  I tried with Riemann's definite integral definition but couldn't proceed


I'm relatively new to blender, working on a tutorial that's supposed to train me on how to use it on youtube.  One part doesn't seem to match up as you'll see. Here's what you see on the tutorial when he clicks "Composition"    it has this modal that's supposed to help with denoising the image.  Here's how it looks on my end, from the layout    with my donut so far, and when I click composition I'm missing that modal    I'm guessing you can add it, I just don't know how to.  My current version is 2.8.2


Is it possible to rent a manual transmission car in Philadelphia Intl?

I'm planning to travel to Philadelphia on january and I would like to rent a car (to avoid walking around or having problems with flight timing), but searching on the net, I haven't been able to find any manual transmission car, be it sedan, sport, deluxe, a transport van, everything is automatic.  Does anybody here know where i could find a manual one?  Edit : this question will stay here as a "how to get a manual car in PHL Intl, and will open new ones for the existing questions if required.


For a distribution function $F(x)$ and constant $a$, integral of $F(x + a) - F(x)$ is $a$.

For any distribution function and any $a \geq 0$, $\int_{-\infty}^{\infty} (F(x+a)-F(x))dx = a$.   In this case, "distribution function" means a right continuous function F with $F(-\infty) = 0$, $F(\infty)= 1$.   This problem comes after a section in the book on mathematical expectation, so I suspect I should use some property of expectation to prove it. Expectation appears to be something that applies to random variables, so I think I should be somehow transforming the problem into something in terms of expectations of random variables, but I'm not sure how. I know that given a distribution function, I can get a probability measure, but I'm not sure how to go from there to a random variable and actually get a relation between the expectation of the random variable and this integral. I'm sure whether this is the right way to go about this problem, but if it is, I'm missing a connection somewhere.


Read a list of URL Strings from a File and Find the top 10 most read URL's

Ok,  I have been getting this question in a tonne of interviews and I think I need some help on solving it.  You have a tonne of URL's say as a String Array or read from a File. You now need to get the top ten most read ones, as in the Top Ten most Frequent URL's in the file.  My approach was:            Read them into a String Array,           Iterate through each String/URL,              At every Iteration, put them into Hashtable, incrementing the count.          Iterate again and find feed the scores into an array          Sort and find the top 10 scores OR use max-heap to get the top 10.          Iterate again and remove the URL's with the top 10 scores.   Is this a very bad answer? Can someone help me further with this?


unset() works on unix platform, not in Windows 10

I have this code to parse through a remote TXT file. It works fine on a remote server which runs on unix, but on Windows 10 Apache, it does not get to the echo
Reached here...
; line.  This is the code:  <?php if (!file_exists('unicode-13.txt')) {     file_put_contents('unicode-13.txt', file_get_contents('https://unicode.org/Public/emoji/13.0/emoji-test.txt')); }  $blocks = explode(PHP_EOL.PHP_EOL, file_get_contents('unicode-13.txt'));  // var_dump($blocks);  unset($blocks[0]);  $emoji = [];  foreach ($blocks as $chunk) {      echo "
Reached here...
";      $top = explode(PHP_EOL, $chunk)[0];      if (substr($top, 0, strlen('# group:')) == '# group:') {          $group = trim(str_replace('# group:', '', $top));      } elseif (substr($top, 0, strlen('# subgroup:')) == '# subgroup:') {          $lines = explode(PHP_EOL, $chunk);         unset($lines[0]);          foreach ($lines as $line) {              $subgroup = trim(str_replace('# subgroup:', '', $top));             $linegroup = explode(';', $line);             $parts = explode('#', $linegroup[1]);             $icon = explode(' ', trim($parts[1]), 2);              $var_codepoint =    trim($linegroup[0]);             $var_status =       trim($parts[0]);             $var_sub_group =    trim($subgroup);             $var_emoji =        trim($icon[0]);             $var_emojiname =    trim($icon[1]);              echo "var_codepoint: " . $var_codepoint . "
";             echo "var_status: " . $var_status . "
";             echo "group: " . $group . "
";             echo "var_sub_group: " . $var_sub_group . "
";             echo "var_emoji: " . $var_emoji . "
";             echo "var_emojiname: " . $var_emojiname . "
";          } // line     } // subgroup } // foreach ?>   I get no errors on Windows - I have verified that the $blocks array is populated on the windows test, as a var_dump($blocks); displays the array.  However, it seems that on windows, none of the code beyond unset($blocks[0]); is fired / reached.  I get no errors in the windows php error log, so I am not sure what might be going on.


C++ Polymorphism: from parent class to child

In C++ we can convert child class pointer to parent, but is there any way to convert it back: from parent, which was obtained from child, give child class back?  I mean:  class Parent {     ... };  class Child : public Parent {     ... };  int main(int argc, char const *argv[]) {     Child* child = new Child();     Parent* parent = child;     Child* old_child = parent; // how to do this??     return 0; }   Thank you for your answers.


I have a JetBlack M1 Pro Mag Trainer. I use my road bike on it, with slick tires. However it is still pretty noisy.   What are the ways to reduce noise from a magnetic trainer?


Notifications for badges on other Stack Exchange sites use the wrong badge icon

Minor bug, but if you get a notification for a new badge the icon used for the badge will be the one for the site you are currently on, not the one where the badge was earned.     The cause of this is the site-wide standardized css file, which means dynamically resolving the badge for each site might be a little complicated and possibly not worth the effort.


which is better from performance point of view - "is" or "as" cast

i have very basic doubt - from performance point of view "is" cast or "as" cast is better to use. Though "as" does not throw exception but it does boxing and hence performance gets affected but still not sure.  if possible please give example for this


Can suspended users post comments? Get notifications? What happens to their reputation?

I have some questions about a suspended user's earning and activity.   Can suspended users get reputation back after the suspension period? If a user is suspended for 7 days and he/she earns reputation during this period. Then will it be calculated after completing suspension period? If a suspended user has awarded a bounty to other user and the awarded bounty marked as illegal. Then will that bounty rolled back to their account?  Can suspended users get any alert from comments or chat room using @username method? Can suspended users post comments on his/her question/answer? If another user replies or ask a question on suspended user's post. Then, can a suspended user give response back?


I've received my visa Tier 1 'exceptional talent' today starting 1st November. I have a flight a few days before (27th October).    Is there any reason to be worried?    I can, in theory change my flight dates, but I have a trip on these days.   I don't require visa just to enter to the UK if it matters at all.


What is the difference between the different methods of putting JavaScript code in an ?

I have seen the following methods of putting JavaScript code in an  tag:  function DoSomething() { ... return false; }    link link link link   I understand the idea of trying to put a valid URL instead of just JavaScript code, just in case the user doesn't have JavaScript enabled. But for the purpose of this discussion, I need to assume JavaScript is enabled (they can't login without it).  I personally like option 2 as it allows you to see what's going to be run–especially useful when debuging where there are parameters being passed to the function. I have used it quite a bit and haven't found browser issues.  I have read that people recommend 4, because it gives the user a real link to follow, but really, # isn't "real". It will go absolutely no where.  Is there one that isn't support or is really bad, when you know the user has JavaScript enabled?  Related question: .


Creating clusters based on attribute and proximity

In my map as you see below, I have my population by district.  I want to create 50 clusters with similiar sums of the population and by proximity. How I can achieve this?  For each cluster, I want the districts are next to each other (As you can see in yellow in the picture).


A few months ago (?) there were some changes to the site aesthetics, including toning down the use of a contrasting background for code and deleted posts. I'd prefer they both come back, but the issue with code seems like a personal preference; I don't have a pragmatic argument and aren't interested in forcing my opinion about it on the world. However, removing the pink tint on deleted posts is a step backward in practical terms.1  It was very clear when something was deleted. I'm a mod, and for me there's a significant practical value to that. Of course that the post has been deleted is not hidden -- there is still a banner clearly stating the fact.  The visual significance of this diminishes with the size of the post, however. A common context for deletions are brand new users who post questions as answers.  Having a glaring visual element (the pink background) no doubt made something pop.  The banner of course is there, and you receive a notification.  Keep in mind, though, this is already someone who wrote up a question and clicked Post Your Answer.  I think long term users may not realize how relatively complex (compared to eg. bb style forums) the SE interface is, and that a normal reaction to that would to to tune out things in accord with whatever you think you are looking at. So: That's several pragmatic reasons to go with the contrasted background; I really don't see any for not doing so, meaning this seems like a sacrifice of functionality for trivial aesthetics.   There's a 10K rep bar on seeing deleted posts, so if you don't know what I'm on about that's probably why.  The bar does not apply to your own posts if deleted.


Which sites are missing from the All Sites list?

On stackexchange.com there is a .  Except that the list does not include all sites.  Today I was reminded of , which is not listed there.  I had forgotten about this site.   is not listed there either, but that's not a Q&A site.  Which other sites exist that are part of Stack Exchange but not listed on stackexchange.com?


Using past tense when referencing a still-true fact

In the sentence: "I didn't know she had a son,"   Can I say "I didn't know she has a son" instead, because he is a teenager now?  Or are both correct?


Difference Between Filter and Action Hooks?

I have been looking at the plugin API a bit more in depth recently and I was wondering what real differences there were between action and filter hooks. They both are events that receive data as a parameter and they seem to both be able to do the same things.  Obviously I see that actions are called when actions take place and filters are called when data is manipulated, but it seems to just be a semantic naming difference.  Besides semantics and what they are used for, what real differences are there between them?


My netbook is an ACER AOD257. It has 1.66GHz, 1 GB of RAM and 320 GB HDD.  I am looking for the fastest Linux operative system on my computer. I have tried Lubuntu and I like it, but it is too much "cold" as operative system, then I have put Ubuntu; 12.04 LTS is the better version; is very fast and nice.  Nevertheless, I am facing another problem: my video card one is a half thunderstruck, 8 MB has gone to 128 MB, then inziavo to have problems also with Ubuntu 12.04 LTS because I had all the active effects.  Later I have passed to Ubuntu Mate 12.04, only that it gives me a problem, the audio is not heard... Then what operative System do you advise?  I would want it fast, nicely, lightly and very versatile. Has my friend advised me Ubuntu Studio, what do you think about it?


Visitor visa to re-enter USA after 1 month in Mexico

My mom came from Venezuela to visit my sister and my family and after 6 months we applied for an extension of stay, she went to Mexico to visit my nephew and his wife but I want her to come back to the USA; how long does she need to be outside before she can re-enter the state?


I've noticed that when writing a shell script, there's a lot of inconsistency in whether people put a space after the I/O redirection operators. For example:  foo >bar.txt   Will work, but so will this:  foo > bar.txt   ....and even this:  foo       >             bar.txt   In fact, even  is frustratingly inconsistent about it - using 2>&1 (which doesn't actually work in my Bash terminal with spaces) in one place and > filename in another!  I've always used the former, as the latter feels like 2 different arguments to me, but I was wondering: Is there any difference or reasoning between the two?  Is >bar.txt more portable than > bar.txt or something? Or should I use 1 syntax in 1 defined situation, and the other in another?


How to make bash put prompt on a new line after cat command?

What I get:  host:~ user$ cat example.txt some texthost:~ stas$   What I want to get:  host:~ user$ cat example.txt some text host:~ stas$   Is there a way I can make cat behave like this?  I'm using bash on Mac OS X.


I have a Mac Pro Mid 2010 that since about a week ago only displays a blank white screen after rebooting. It doesn’t respond to various startup options. My reseller advised my to replace the original ATI Radeon 5870 graphics card.   I installed a new Sapphire Pulse RX 580 (so that I can later upgrade the Mac OS from 10.13.6 to 10.15) plus new cable, but see nothing at all on the monitor. I assume the bios doesn’t recognize the card as I could not install any software. How can I solve this?  Could I temporarily install an ATI Radeon 5770 that has been used in a PC just to install software for the RX 580?  Any alternatives?


Registering a domain name with a trademark in it

One of our competitors is lets say called WidgetMaker.  They target Macs.  We target Windows computers.    WidgetMaker is a trademarked term.  I'm assuming the answer to this question is no, but could we register "www.WidgetMakerAlternative.com"?


Understanding difference between functions

I understand what the code below does:  var x = myFunction(3, 4)  function myFunction (a, b) {     return a * b; }  console.log(x);   It will create a function called myFunction, call it with 3 and 4 and return 12.  But I don't understand what the difference between the above code and the code below.  var myFunction = function (a, b) {     return a * b; };  var x = myFunction(3, 4) console.log(x);   If we can write code like the first one, why do we need to write code like the second one?  Thanks.


Here I got  public class Planet {      ArrayList<Person> person  = new ArrayList<>();     Iterator<Person> itr = person.iterator();      public String getFemaleName()     {          for (int a = 0;a < person.size();a++)         {             if (person.getGender == "female")             {                 return person.get(a).getName();             }         }     } }   Now I'm having 2 problems, 1st is i just want return female's name,but it seems I have to return something even there is no female in my ArrayList. 2nd is how to use an Iterator instead of using a for loop.


Given three strings, how would one go about sorting them?

I've come across an issue whilst doing some homework. The problem is to take three strings and sort them. I've gotten this down for numbers but I don't know how to accomplish this with strings.  Here it is verbatim from the book:  Write a program that reads three strings and prints them in lexicographically sorted order.  Please enter three strings: Tom Dick Harry The inputs in sorted order: Dick Harry Tom   My Tester:  package Chapter_5;  import java.util.Scanner;  public class StringOrderTester  {     public static void main(String[]args)     {         Scanner in = new Scanner(System.in);          System.out.println("Please provide three strings:");          StringOrder str = new StringOrder(in.nextLine(),in.nextLine(),in.nextLine());     } }   My Code:  package Chapter_5;  public class StringOrder  {     public StringOrder(String str1, String str2, String str3)     {         String index;          int i = str1.compareTo(str2);          System.out.println(i);     } }


I'm manually creating a sprite sheet using Photoshop and many of the graphic elements have drop shadows applied. Given that fact, it's tough at times to see where the drop shadows begin and end. I don't want to set my guides too close and cut off parts of the shadow. Anyone have any tips on how they go about handling this issue?


Minecraft - Command activating when enitiies = x-number using command blocks

So I am trying to figure out how to teleport someone within a radius, but only when there is one entity left within that radius. I was trying this:  /tp @p[c=1] x y z   But the c is only for how many people you wish to teleport. So my mind jumped to:  /tp @p[entity=1] x y z   But as far as I'm aware you, can't specify entity under @p. I am rather new to command blocks in general. Is it possible, and if yes, how? I would normally like to figure it out myself because I learn better that way, but this is too confusing for me. If it is possible I would rather just be told how to figure it out without giving me the complete answer, but at this point I'll be content with anything.


Chances of seeing 5 losses in a row if chance of loss is (1/8) and you play 4,320 times?

Say you are playing a completely random game. You have a (7/8) chance to win, and a (1/8) chance to lose.  What are the chances that you would lose 5 times in a row?, if you played the game 4,320 times?  What is the formula for this?


I have installed dropbox on ubuntu 16.04.  I have had it run before.  Now I have restarted and it is not running.   How do I start it manually, as I don't want it to automatically start on startup?


What is the BIOS boot area and do i need it. I have a bare new drive and I plan on resorting back to dual-booting windows. I had re-re-installed Ubuntu and windows several time and it did not work. I would only get windows to boot or a error message saying "please install a operating software media"  So looking into the installer, i found this "BIOS boot area" I have no idea what this dose or if i need it (yes I've done research on what it dose, but not in full detail nor do I understand it). So do I need to use "BIOS boot area" for dual boot and do I half to install windows on the PC first before Ubuntu??


I am using Ubuntu 14.04. I like default unity desktop environment, but now I want to try Kubuntu. So please tell me a way to do that.  I should have options for choosing which desktop environment to start at log in screen as i do not want to replace unity with KDE. So please help me... Thanks in advance!!!!


What are the $5$ different combinations of $4$ numbers that can add to $8, 9, 10$ or $11$?

There are $5$ combinations of $4$ numbers from $1-9$. If you write these on two coins, so there are $2$ numbers on each coin. Then you flip the coin. The sum of the two numbers add to $8,9,10,$ or $11.$  In other words, you can combine $2$ numbers to make $8,9,10,$ or $11.$  What are the combinations


Let $g$ be a continuous function on $\mathbb{R}$ such that:  $\displaystyle\lim_{x \to 0} \:\dfrac{g(2x)-g(x)}{x}=l \in \mathbb{R}.$   I am supposed to prove that $g$ is differentiable at $0$ and $g'(0)=l$  Here is what I did: $$\displaystyle\begin{align} \lim_{x \to 0} \:\dfrac{g(2x)-g(x)}{x}&=\lim_{x \to 0}\:\frac{2(g(2x)-g(0))}{2x}-\dfrac{g(x)-g(0)}{x}\\&=\lim_{X \to 0}\:2\:\dfrac{g(X)-g(0)}{X} - \lim_{x \to 0}\:\dfrac{g(x)-g(0)}{x}\\ &=\lim_{x \to 0}\:\dfrac{g(x)-g(0)}{x}\\ &=l  \end{align}$$ Since $\displaystyle\lim_{x \to 0} \:\dfrac{g(x)-g(0)}{x} = l$, then g is differentiable in $0$ and $g'(0)=l$  Is this valid? I'd appreciate any suggestion thanks.


Lagrangian, central forces and conservation of angular momentum

When studying central forces it is possible to propose the Lagrangian:   $$ L = T-U=\frac{1}{2}m \dot{r}^2+\frac{1}{2}mr^2 \dot{\theta}^2 - U(r)$$   Then we can solve the equation of motions for $\theta$: $$ \frac{d}{dt}\frac{\partial}{\partial \dot{\theta}}L-\frac{\partial}{\partial \theta}L=0=\frac{d}{dt}\left( mr^2\dot{\theta}\right)  \rightarrow mr^2\dot{\theta} = constant = l$$  Then  $\dot{\theta} = l/mr^2$   Why can't I take this equality and put it into the Lagrangian $\mathcal{L}$ before solving the equations of motion for $r$? So:   $$ L = \frac{1}{2}m \dot{r}^2+\frac{l^2}{2 mr^2}  - U(r) $$   $$ \frac{d}{dt}\frac{\partial}{\partial \dot{r}}L-\frac{\partial}{\partial r}L=0\rightarrow\frac{d}{dt}(mr)+\frac{l^2}{mr^3}+\frac{\partial}{\partial r}U(r)=0$$   The result would be obviously different if I solve the equations for $r$ and then substitute $\dot{\theta} = l/mr^2$:  $$L = \frac{1}{2}m \dot{r}^2+\frac{1}{2}mr^2 \dot{\theta}^2 - U(r)$$  $$\frac{d}{dt}\frac{\partial}{\partial \dot{r}}L-\frac{\partial}{\partial r}L=0\rightarrow\frac{d}{dt}(mr)-\frac{l^2}{mr^3}+\frac{\partial}{\partial r}U(r)=0$$   In this case, the difference is the sign on the angular momentum term. But in general, it is not the same at all. Why is solving the Euler-Lagrange Equation first the right approach?


Skype with both system and microphone audio in El Capitan

I'm trying to use Skype for screen sharing with simultaneous audio from my microphone and the Mac system (for example a video or a game).   Using Soundflower, and in the Audio Midi Setup an Aggregate Device for input and a Multi-Output Device for output I've been able to get either Mac system audio or microphone (voice), but not both.   In some settings, both seem to be input, but only the system audio is output, or just a very quick bit of voice can be heard before cutting out.  I'm stumped...  Here are the Skype audio settings:   And here are the Mac settings:  First, Audio Midi Setup     And Sound from System Preferences    I have found some videos on YouTube that discuss this, like  which I've followed, but still no luck.   Thanks. Any help is truly appreciated!


Airfoil theory --- Why does air travel faster above?

I do not understand, why the air above the airfoil travels faster than the air below it? The air above has to travel faster than the air below so that both streams meet simultaneously at the trailing edge --- why do the streams have to meet simultaneously ?   PS : I understand the Bernoulli principle and how the lift is created by the pressure difference and all that.


Machine requirement for hosting a load balancer (Nginx)

We are planning to migrate an application from AWS cloud to on-prem. For our application, we were using AWS ALB. For on-prem deployment, we are planning to use an Nginx load balancer. But I'm not sure about what configuration is required for hosting the load balancer because in the cloud (AWS) we are not concerning about the machine specs.   What are the criteria for selecting a machine as a load balancer? I mean the RAM, CPU, etc. I'm afraid that if I choose a 4GB machine will that be enough for the load balancer? How can I choose the machine?


Proper usage of "since" and "from" with regard to duration of time

When you returned, I had been at home since 10 minutes.   When you returned, I had been at home from 5 minutes.  In such sentences, is it correct to use since or from? When since is used?


Why did Snape tell Voldemort when Harry Potter was really going to be moved?

It seems suspicious that Snape told Voldemort when Harry Potter would be moved from his home. At that point of time, he had Voldemort's complete trust, having killed Dumbledore, why did he need to perform an extra attempt to help Voldemort find Harry Potter?


How to create a list template by using CSOM?

For creating a list template programmatically by using server object, I'm using the SaveAsTemplate() function.  SPSecurity.RunWithElevatedPrivileges(delegate {   using (SPSite oSPsite = new SPSite(strSiteURL))   {     oSPsite.AllowUnsafeUpdates = true;     using (SPWeb oSPWeb = oSPsite.OpenWeb())     {       oSPWeb.AllowUnsafeUpdates = true;        SPList list = oSPWeb.Lists[strListName];       string bkpTemplateName = "bkp" + strListName + ".stp";       list.SaveAsTemplate(bkpTemplateName, bkpTemplateName.Replace(".stp",""), "Description", true);        list.Update();       oSPWeb.AllowUnsafeUpdates = false;     }     oSPsite.AllowUnsafeUpdates = false;   } });   But, is there a way to do the same by using CSOM?


I think the following two formulas are true:  $$ \mathrm{Var}(aX)=a^2  \mathrm{Var}(X) $$ while a is a constant number $$ \mathrm{Var}(X + Y)=\mathrm{Var}(X)+\mathrm{Var}(Y) $$ if $X$, $Y$ are independent  However, I am not sure what is wrong with the below:  $$\mathrm{Var}(2X) = \mathrm{Var}(X+X) = \mathrm{Var}(X) + \mathrm{Var}(X) $$ which does not equal to $2^2 \mathrm{Var}(X)$, i.e. $4\mathrm{Var}(X)$.  If it is assumed that $X$ is the sample taken from a population, I think we can always assume $X$ to be independent from the other $X$s.  So what is wrong with my confusion?


Movie Identification - 1990s VHS Sci-Fi/Horror

Okay, this is a hard one as I don't remember very much, and can't figure out what to Google, but here goes. This is one of those 1990 straight to VHS type movies (probably) with decent production value.   From what I remember, a family moves to a dangerous, hot environment where you would be burned outside in the day in a short period of time. The father is possibly a scientist, and is working with plants (maybe reptiles) in the family's basement. The boy becomes affected by his father's work and is an outcast at school. One scene involved him being left outside to burn tied to a post, where he survived due to his affliction. His dad may form into a planet like creature in the end, or the planet is eating his family..possibly.  This may be all in my head, but I am pretty sure it was a movie.


I have a four points in plane and need to test (based on point coordinates) whether they are able to form a convex quadrilateral:    Of course, the test should avoid configurations like these:      Given the diagonals, I can check whether the quadrilateral is convex (simply checking whether the intersection of diagonals is between both ends of both diagonals).  The real problem is how to label the four points and filter out all concave and degenerate configurations (like, for example: $A=B$).  If the labeling is possible (convex case found), the four points should be labeled such that $AC$ and $BD$ are diagonals of a convex quadrialteral.  I wonder if there is an elegant solution (rather than testing every possible permutation of $A, B, C$ and $D$).


I'm trying to understand what is exactly a file system. I found various answers on the web including the ones provided here: . While these answers provide valuable informations, it's still unclear to me whether a file system is: a - A collection of data structures (inodes, master file table, file allocation table, ...) that index files and directories . b - A collection of data structures that index files and directories and the file tree. c - A file tree (mounting a file system, mounting a network file system, the /proc file system).


Grubrescue pops up and won't let me do anything

Okay so here is the deal: My mother-in-law's ex boyfriend installed Ubuntu on her computer, due to the fact that she isn't very good with computers, I now have to install windows 7 on it. I started the install after a long time trying to get the damn thing to boot from the disc. Halfway through something went wrong and it told me to retry. Now it pops up with whenever i try to boot from the CD again:  Error: unknown filesystem entering rescue mode... grub rescue>  I have formatted the drives, but somehow grub is still there (no idea how?) Now how do I delete this stuff and install windows?


How do i change the start up background music in Ubuntu and can i add any customized music for startup? What are the various ways of setting this?


Why use the derivative and not the symmetric derivative?

The symmetric derivative is always equal to the regular derivative when it exists, and still isn't defined for jump discontinuities. From what I can tell the only differences are that a symmetric derivative will give the 'expected slope' for removable discontinuities, and the average slope at cusps. These seem like extremely reasonable quantities to work with (especially the former), so I'm wondering why the 'typical' derivative isn't taken to be this one. What advantage is there to taking $\lim\limits_{h\to0}\frac{f(x+h)-f(x)} h$ as the main quantity of interest instead? Why would we want to use the one that's defined less often?


Are 'The Lost Missions' part of the official Star Wars canon?

The new Disney canon includes Star Wars: The Clone Wars TV series, but are The Lost Missions (e.g. the unfinished season 6 of Star Wars: The Clone Wars) considered a full part of the Star Wars canon?


Timing a Python program using time.clock() vs. time.time()

I am new to Python programming. I started working on Project Euler this morning and I wanted to find out how long it takes to execute my solution. I have searched online for a solution to my   import time  class Solution(object):     def fibonacci(self,limit):         sum = 0         current = 1         next = 2         while(current <= limit):             if  current % 2==0:                 sum += current             current, next = next, current + next          return  str(sum)  if __name__ == "__main__":     start = time.clock()     solution = Solution().fibonacci(4000000)     elapsed = time.clock()-start     print("Solution: %s"%(solution))     print("Time: %s seconds"%(elapsed))     Output: Solution: 4613732 Time: 2.006085436846098e-05 seconds    import time  class Solution(object):     def fibonacci(self,limit):         sum = 0         current = 1         next = 2         while(current <= limit):             if  current % 2==0:                 sum += current             current, next = next, current + next          return  str(sum)  if __name__ == "__main__":     start = time.time()     solution = Solution().fibonacci(4000000)     elapsed = time.time()-start     print("Solution: %s"%(solution))     print("Time: %s seconds"%(elapsed))     Output: Solution: 4613732 Time: 0.0 seconds    My question is    Is the time calculated above correct? What is the difference between time.time() vs time.clock(). If I use time.time() I get 0.0 as time.