I am bit confused when to use this keyword. I know usually we use them to set parameters in constructors or if we have multiple constructors, however, which approach below is correct?   public class ResultsPage {      private WebDriver driver;     private JavascriptExecutor jsx;         private Selector selector;     private WaitFor waitFor;     private WebElementUtilities webElementUtilities;      public ResultsPage(WebDriver driver) {         this.driver = driver;         this.webElementUtilities = new WebElementUtilities(driver);         this.selector = new ReactSearchResultsPageSelector();         this.waitFor = new WaitFor();                     this.jsx = (JavascriptExecutor) driver;     }  }   or   public class ResultsPage {      private WebDriver driver;     private JavascriptExecutor jsx;         private Selector selector;     private WaitFor waitFor;     private WebElementUtilities webElementUtilities;      public ResultsPage(WebDriver driver) {         // I used this here since the parameter has the same name.         this.driver = driver;          // I did not use this here but should I?         webElementUtilities = new WebElementUtilities(driver);         selector = new ReactSearchResultsPageSelector();         waitFor = new WaitFor();                     jsx = (JavascriptExecutor) driver;     }  }


I am currently reading Murphy's ML: A Probabilistic Perspective. In CH 3 he explains that a batch update of the posterior is equivalent to a sequential update of the posterior, and I am trying to understand this in the context of his example.  Suppose $D_a$ and $D_b$ are two data sets and $\theta$ is the parameter to our model. We are trying to update the posterior $P(\theta \mid D_a, D_b)$. In a sequential update, he states that, $$ (1) \ \ \ \ \ \ \ \  P(\theta \mid D_{a}, D_{b}) \propto P(D_b \mid \theta) P(\theta \mid D_a) $$ However, I am slightly confused as to how he got this mathematically. Conceptually, I understand that he is saying the posterior $P(\theta \mid D_a)$ is now a prior used to update the new posterior, which includes the new data $D_b$, and is multiplying this prior with the likelihood $P(D_b \mid \theta)$. Expanding the last statement out, I have, $$  P(D_b \mid \theta) P(\theta \mid D_a) = P(D_b \mid \theta) P(D_a \mid \theta) P(\theta) $$  but are we allowed to say $P(D_a \mid \theta) P(D_b \mid \theta) = P(D_a, D_b \mid \theta)$ in order to make the connection in (1)?


Is there a gender-neutral term for witches and wizards?

When writing questions and answers here about the Harry Potter series, I often need a word for "someone who's not a Muggle". People often refer to "the wizarding world" as opposed to the Muggle word, so "wizard" would be one choice - but it seems slightly sexist to exclude witches in that way. On the other hand, "witch or wizard" is a bit cumbersome, much longer than the simple word "Muggle".  Is there a sensible word to use which is neither sexist nor cumbersome, that makes a good equivalent to "Muggle"? What would JK Rowling say to fill in a sentence such as this:     Muggles use technology, while [...] use magic.


Hi all :) I want to create a KVM image from an existing iso file (for glance on OpenStack), but I didn't find how to do it. Can you help me please?


Macbook retina 15" mid-2012 with LG 38UC99-W

I'm interested in buying a LG 38UC99-W monitor. I'm only wondering if my mid-2012 macbook pro 15" will support it?  MacBook Pro (Retina, Mid 2012)  Graphics:         NVIDIA GeForce GT 650M 1024 MB   Intel HD Graphics 4000 1536 MB      I do have a display-port cable, so I don't need to connect it via HDMI. As I read that this macbook model could be limited on this. Or am I wrong?


How can I get file extensions with JavaScript?

See code:   var file1 = "50.xsl"; var file2 = "30.doc"; getFileExtension(file1); //returns xsl getFileExtension(file2); //returns doc  function getFileExtension(filename) {     /*TODO*/ }


Prove that $n^2 + (n + 1)^2 = m^3$ does not have solutions in the positive integers.  I guess that the proof is by contradiction, but if I suppose it, I can't find the contradiction.  Thanks for your help.


Is it bad to answer a question you know to be off-topic?

If someone asks a question that is overly broad or possibly opinionated, but you think you could give a useful answer to the asker and help them out a bit, is it bad to answer the question even if you know it will most likely be closed?  On one hand it helps the person better have a grasp of the question they want to ask (maybe answer a broad question by skimming the surface of all the things they need to be thinking about to answer their question, and it could help them ask a more useful question).  On the other hand it may reward the user for incorrect behavior, and be seen by outsiders as the correct way to ask a question.  So what do you guys think, is there ever a time when answering a question you know to be off-topic could be beneficial?


Fitting t distribtution to financial data

The data I am using can be found here:  The variable is called "alvsloss".  I want to fit a distribution to my financial data. First of all, I started with a normal distribution.  The pdf is given by:  $\frac{1}{\sqrt{2\pi\sigma^2}}\operatorname{exp}\left\{-\frac{\left(x-\mu\right)^2}{2\sigma^2}\right\}$  and the log likelihood, which is to be maximized is given by  $  \ln\mathcal{L}(\mu,\sigma^2) = \sum_{i=1}^n \ln f(x_i;\,\mu,\sigma^2) = -\frac{n}{2}\ln(2\pi) - \frac{n}{2}\ln\sigma^2 - \frac{1}{2\sigma^2}\sum_{i=1}^n (x_i-\mu)^2. $  which gives as a solution  $   \hat{\mu} = \overline{x} \equiv \frac{1}{n}\sum_{i=1}^n x_i, \qquad \hat{\sigma}^2 = \frac{1}{n} \sum_{i=1}^n (x_i - \overline{x})^2. $  I can calculate this in R via mean(alvsloss) and sd(alvsloss) and get the values -0.0004270872 and 0.02304159 or I do   library(MASS) fitdistr(alvsloss, "normal")   and get the solution         mean             sd         -0.0004270872    0.0230371244   ( 0.0004535429) ( 0.0003207033)   Ok, I understand this. But now my problem arises, I tried this with the t distribution. The pdf is given by:  $\textstyle\frac{\Gamma \left(\frac{\nu+1}{2} \right)} {\sqrt{\nu\pi}\,\Gamma \left(\frac{\nu}{2} \right)} \left(1+\frac{x^2}{\nu} \right)^{-\frac{\nu+1}{2}}\!$  the log likelihood can be found here:  formula (17.8) (x is denoted by $\epsilon$. I am not understanding where the $h_i$ comes from in the formula, but this is not my main question.)  First question: Seems to me, that there is no closed form solution?  Second question: I do fitdistr(alvsloss, "t")  and get the output    m               s               df         -0.0004919768    0.0130128873    2.6340459185   ( 0.0003182568) ( 0.0003453702) ( 0.1620424078) Es gab 28 Warnungen (Anzeige mit warnings())   I am not understanding, why I have three parameters now? The df is the $\nu$, but the others? What is R doing? Since there is no closed form solution, I guess it is using a iterated algorithm? Should I bother about the 28 warnings? They are:  Warnmeldungen:  1: In dt((x - m)/s, df, log = TRUE) : NaNs wurden erzeugt 2: In dt((x - m)/s, df, log = TRUE) : NaNs wurden erzeugt 3: In dt((x - m)/s, df, log = TRUE) : NaNs wurden erzeugt 4: In dt((x - m)/s, df, log = TRUE) : NaNs wurden erzeugt 5: In dt((x - m)/s, df, log = TRUE) : NaNs wurden erzeugt 6: In dt((x - m)/s, df, log = TRUE) : NaNs wurden erzeugt 7: In dt((x - m)/s, df, log = TRUE) : NaNs wurden erzeugt 8: In log(s) : NaNs wurden erzeugt 9: In log(s) : NaNs wurden erzeugt 10: In log(s) : NaNs wurden erzeugt 11: In log(s) : NaNs wurden erzeugt 12: In log(s) : NaNs wurden erzeugt 13: In log(s) : NaNs wurden erzeugt 14: In log(s) : NaNs wurden erzeugt 15: In log(s) : NaNs wurden erzeugt 16: In log(s) : NaNs wurden erzeugt 17: In dt((x - m)/s, df, log = TRUE) : NaNs wurden erzeugt 18: In log(s) : NaNs wurden erzeugt 19: In log(s) : NaNs wurden erzeugt 20: In dt((x - m)/s, df, log = TRUE) : NaNs wurden erzeugt 21: In dt((x - m)/s, df, log = TRUE) : NaNs wurden erzeugt 22: In dt((x - m)/s, df, log = TRUE) : NaNs wurden erzeugt 23: In log(s) : NaNs wurden erzeugt 24: In log(s) : NaNs wurden erzeugt 25: In log(s) : NaNs wurden erzeugt 26: In log(s) : NaNs wurden erzeugt 27: In log(s) : NaNs wurden erzeugt 28: In log(s) : NaNs wurden erzeugt   And how can I plot this distribution with the estimated parameters?


Mean of floor of a division of Poisson random variable

I have a r.v. $X$~Poisson($\lambda$). Denote $Y=⌊X/a⌋$. What will be the distribution of $Y$ and how to calculate its mean? (A relaxation can be made if it makes the problem simpler: $a$ is an integer).  What I got so far: $P(Y=k)=P(X∈[ak,ak+a))=Fx(⌊ak+a⌋)-Fx(⌈ak⌉),k=0,1,2,... $, where $Fx$ is the CDF of r.v. $X$.   I can't go any further and derive a closed-form expression for $E[Y]$.  Any help will be much appreciated. Thank you.


Prove that $\overline{ \lim} ~u_n\overline{\lim}~v_n\geq \overline{\lim}~u_nv_n$

Problem: Let $\{u_n\}_n$ and $\{v_n\}_n$ be two bounded sequences and $u_n>0, v_n>0$ for all $n\in \mathbb{N}$. Prove that $$\overline{\lim }~u_n\cdot \overline{\lim}~v_n\geq \overline{\lim}~u_n v_n.$$  Progress: Since $\{u_n\}_n$ and $\{v_n\}_n$ are bounded , there exis $K_1,K_1>0$ such that $|u_n|\leq K_1$ and $|v_n|\leq K_2$ for all $n\in \mathbb{N}$. What can I do next to  prove that result?


Edit: This just got marked as a duplicate of a question on calling a Bash command. I daresay anyone familiar with programming should be aware that "calling a Bash command" is vastly different from sucking down a resource by HTTP and sending its output to another program.  Does anyone have sample code showing how to achieve this kind of thing in Ruby:  curl http://stackoverflow.com | wc   I know I could use system, but would ideally like to keep it pure Ruby using IO.pipe or whatnot.


a large number of/ large numbers of, What's the difference?

Tests are hard to solve for large number of users.   Checking the similar usage of such expression, I think there is something wrong with the sentence. What's the best and correct? a large number OR large numbers OR even something else!


Closing unused credit cards: how much will it really hurt?

I have three credit cards, but I only use the newest. I pay it off in full every month, and the two older credit cards haven't seen a single transaction in over a year. None have an annual payment, so it doesn't hurt anything to keep them, but I just don't like having these unused credit cards sitting around and I'd like to simplify stuff.  I'm in the process of buying a house, and I'll of course wait until after closing to get rid of my unused credit cards. If I have to replace my car, I'll buy a used car with cash. So, after closing on my mortgage, I don't expect to be applying for credit for at least a few years. My credit score is currently very good, so I feel like I have some room to breathe, and I rarely hit 30% utilization on the one credit card I actually do use, so I'm not concerned about high utilization or bumping up against my credit limit.  I know my credit score will take a bit of a hit, but I have a student loan that I'm still making payments on (about 15k left on that), and will have a mortgage that I'll be making payments on. I always make my payments on time, so I feel that any impact will be small and short-lived. Is there anything I'm not thinking about here?


Confusion I have regarding Einstein's 1905 derivation of LT

In his 1905 , Einstein derives the Lorentz transformation using the two postulates of SR;constancy of $c$ for all inertial frames and the Invariance of the laws of physics for all inertial frames.   I'll summarize his mathematical derivation and then ask one specific question about it.  So we consider two frames $(x,y,z,t)$ and $(\xi,η, ζ,\tau)$ in relative motion along the x-axis with velocity $v$, and we're interested in finding a spacetime transformation that relates thier coordinates.   We consider some arbitrary point $x'=x-vt$. This point is at rest in  $(\xi,η, ζ,\tau)$ since it's moving with $v$, Therefore this point has $x',y,z$ coordinates that is independent of time, in other words the distance between that point and the origin of $(\xi,η, ζ,\tau)$ is constant.    We consider the following scenario: hit a beam of light from the origin of $(\xi,η, ζ,\tau)$ at $\tau_0$ arriving at the point $x'$ at $\tau_1$ and then being reflected and arrive at the origin of $(\xi,η, ζ,\tau)$ at $\tau_2$.  So that we have: $1/2(\tau_0+\tau_2)=\tau_1$. Since $\tau$ is a function of $(x,y,z,t)$ we have:  $\dfrac{1}{2}[\tau(0,0,0,t)+\tau(0,0,0,t+\dfrac{x'}{c-v}+\dfrac{x'}{c+v})]=\tau(x',0,0,t+\dfrac{x'}{c-v})$  Assuming that $x'$ is infinitely small then taylor expanding this equation and approximating it to first order we get:  $\dfrac{\partial \tau}{\partial x'}+\dfrac{v}{c^2-v^2}\dfrac{\partial\tau}{\partial t}=0$  Solving it then we have:   $\tau=a(t-\dfrac{v}{c^2-v^2}x')$  where $a$ is some unkown function of $v$ (in fact $a=1$).  Finally consider a beam of light emitted from $(\xi,η, ζ,\tau)$ at the origin, it's $\xi$ coordinate is given by  $\xi=c\tau=ca(t-\dfrac{v}{c^2-v^2}x')$  It's given by $\dfrac{x'}{c-v}=t$ in $(x,y,z,t)$, plugging in for $t$ we get:  $\xi=a\dfrac{c^2}{c^2-v^2}x'$  He then states:      Substituting for $x'$ its value, we obtain   $\xi=a\dfrac{1}{\sqrt{1-v^2/c^2}}(x-vt)$   ...   My question is:  1) the three equations $\tau=a(t-\dfrac{v}{c^2-v^2}x')$ and $\xi=c\tau$ and $x'=x-vt$ when combined together gives :  $\xi=c\tau=ca(t-\dfrac{v}{c^2-v^2}x')=a\dfrac{c^2}{c^2-v^2}x'$, since $x'=x-vt$ by plugging in we get:  $\xi=a\dfrac{c^2}{c^2-v^2}(x-vt)=a\dfrac{1}{1-v^2/c^2}(x-vt)$ not $a\dfrac{1}{\sqrt{1-v^2/c^2}}(x-vt)$ .  But He says     Substituting for $x'$ its value, we obtain   $\xi=a\dfrac{1}{\sqrt{1-v^2/c^2}}(x-vt)$   ...   All these equations are copied from Einstein's original paper, So what is wrong with my calculations that does not make it match up with that of Einstein?


How can I compute $$\int_0^\infty\frac{1}{(1+x^{2015})(1+x^2)}\quad?$$    My attempt: Looking at the limits of the integration I see that we should induce some $\tan^{-1}(x)$ so if we put $\infty$ we would get something like $\frac{\pi}{2}$ . But I am not sure how to proceed . Partial fractions don't yield good integral.


When we talk and already have a context, can we omit components such as "the", "of" or "in"? In the examples below, I want to talk about the students of Harvard University only, but I don't want to repeat "the students of Harvard University" because that is too long. I came up with a few alternatives like these below. Which are acceptable to you? I guess that with a clear enough context, all of these are correct, right?  (1) When you were at Harvard University, were students asked to do voluntary work?   (2) When you were at Harvard University, were the students asked to do voluntary work?   (3) When you were at Harvard University, were the students of the university asked to do voluntary work?   (4) When you were at Harvard University, were the students at the university asked to do voluntary work?


I have a large number of data. If i have to represent the data by the central tendency, which one i have to use, mean or median? The value of standard deviation is so huge too. Thanks.


Who lifts more, a Barbarian or a BEARbarian?

In short: Do totem barbarian features continue after they are polymorphed?   In long: The 6th level bear totem barbarian feature doubles carrying capacity. Carrying capacity is your strength times 15 in pounds. With strength of 16, he can carry 240 pounds. Then double it for the bear totem to 480 pounds.    If this barbarian was polymorphed into a polar bear, they would have strength 20, so a carrying capacity of 300 pounds. If bear totem still applies, this doubles to 600 pounds.   Unknown: I don't know how or if, size affects this as the barbarian is medium and the bear is large.


How can I grant read-only acces to my harddrive to guest user?

I want to allow 'guest' user to only read files in my harddrive (mounted during startup at '/mnt/blahblahblah' ) . However I don't want them to write anything into it.I'm on Xubuntu 16.04. How can i do it?


Starting MySQL fails after upgrading to MySQL 5.6

While setting up a test server for the development of a Magento plugin, I ran into the requirement of MySQL 5.6. I was already using MySQL 5.5 so running apt-get install mysql-server-5.6 should have done the trick. Upon finishing the installation, this happened:  [....] Starting MySQL database server: mysqldNo directory, logging in with HOME=/ [FAIL. . . . . . . . . . . . . . . . . . . . . . . . . . . . failed! invoke-rc.d: initscript mysql, action "start" failed. dpkg: error processing package mysql-server-5.6 (--configure):  subprocess installed post-installation script returned error exit status 1 dpkg: dependency problems prevent configuration of mysql-server:  mysql-server depends on mysql-server-5.6; however:   Package mysql-server-5.6 is not configured yet.  dpkg: error processing package mysql-server (--configure):  dependency problems - leaving unconfigured Processing triggers for libc-bin (2.19-22) ... Errors were encountered while processing:  mysql-server-5.6  mysql-server E: Sub-process /usr/bin/dpkg returned an error code (1)   The MySQL server won't start anymore. I've tried service mysql start but the same thing happens. Any suggestions? I'm running Debian 7.  Thanks in advance, Roemer Bakker


if i have two particles in states: |1> and |2> respectavly , and they are not identical then the combined state is |1>|2> ,  but if they are identical then the labels 1 or 2 are arbitrary and could be swapped so supposedly we get two options:   bosons   = |1>|2> + |2>|1> fermions = |1>|2> - |2>|1>   Why there are only these two options ? can't you have any arbitrary superposition of the two states ? (eg: a|1>|2> + b|2>|1> , a*a + b*b = 1)


What is a word to describe a statement that seems meaningless

Is there a phrase or word in the English language that describes a statement or a discourse that seems meaningless or so broad it lacks value?  For example     Society grows best when those who plant trees don't expect to sit in   shade.   While the sentence is cohesive, I personally find it meaningless. Is there a word to describe this? Saying this statement is trivial wouldn't be correct, as the implications are not obvious.   Basically I'm asking what's a politically correct synonym for saying something is "bullshit".   Another example is this quote     We are prisoners in the present, locked in eternal transition between   our past and our future.   Perhaps in context it's meaningful but to arbitrarily say we are prisoners of the present, I personally find is idiotic.


How do all of these "Save video from YouTube" services work?

I mean, how do they work, generally? How do they receive the link to a video stream itself (not just the page containing a Flash player)?  I did a search on the web but couldn't find anything useful (all links point to such services, but none of them tell how they are actually implemented).


after replacing micro usb port, tablet charges only 450mah

I changed micro usb port which was broken (it takes out from motherboard) on tablet. On motherboard are 5 contacts and one is damaged (4. - it is for data transfer, ID). I solder +5 VDC contact and Ground, and left 4,3,2 pins for data transfer (not solder them). Now tablet is charging but "only" with 450mA. Why charging chip doesnt increase charging power more than 450mah. I think that 4,3,2 pins are not needed for charging by charger, only for data transfer and smart recognition. Am I right or wrong?


NullPointerException while trying to display a Bitmap

From the logcat I understand that the Activity crashes because of NullPointerException causes by this line of code.   mImageView.setImageBitmap(decodeSampledBitmapFromResource(getResources(),                                     R.id.picture, imageWidth, imageHeight));   I have read articles about similar problem but still getting NullPointerException. I think that mistake right under my nose, but still I can't catch it.  Where should I put this line to avoid NullPointerException?  @Override public void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState); ...     ImageView mImageView = (ImageView) findViewById(R.id.picture);      BitmapFactory.Options options = new BitmapFactory.Options();     options.inJustDecodeBounds = true;     BitmapFactory.decodeResource(getResources(), R.id.picture, options);     int imageHeight = options.outHeight;     int imageWidth = options.outWidth;      mImageView.setImageBitmap(decodeSampledBitmapFromResource(getResources(),                                 R.id.picture, imageWidth, imageHeight)); }  public static Bitmap decodeSampledBitmapFromResource(Resources res, int resId,                                                      int reqWidth, int reqHeight) {      // First decode with inJustDecodeBounds=true to check dimensions     final BitmapFactory.Options options = new BitmapFactory.Options();     options.inJustDecodeBounds = true;     BitmapFactory.decodeResource(res, resId, options);      // Calculate inSampleSize     options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);      // Decode bitmap with inSampleSize set     options.inJustDecodeBounds = false;     return BitmapFactory.decodeResource(res, resId, options); } public static int calculateInSampleSize(         BitmapFactory.Options options, int reqWidth, int reqHeight) {     // Raw height and width of image     final int height = options.outHeight;     final int width = options.outWidth;     int inSampleSize = 1;      if (height > reqHeight || width > reqWidth) {          final int halfHeight = height / 2;         final int halfWidth = width / 2;          // Calculate the largest inSampleSize value that is a power of 2 and keeps both         // height and width larger than the requested height and width.         while ((halfHeight / inSampleSize) > reqHeight                 && (halfWidth / inSampleSize) > reqWidth) {             inSampleSize *= 2;         }     }      return inSampleSize; }   and here is ImageView from layout.  <ImageView         android:layout_height="240dp"         android:layout_width="199dp"         android:src="@drawable/galaxy"         android:id="@+id/picture"         android:layout_gravity="center_horizontal"         android:scaleType="fitCenter"         android:layout_weight="0.19" />


Is a small fragment of a white dwarf stable?

Assuming it is somehow possible to get a small piece of a white dwarf (maybe a dice) and this piece escapes into free space. Would that piece of white dwarf matter keep its density/state, or would it expand, explode, or transform into another state without the huge gravitational force of the whole white dwarf it was captured in before? There is a similar question here for neutron stars: . Neutrons decay without the large pressure inside the neutron star, so the fate of a piece of neutron star material is clear. But what would happen to white dwarf material? I think the state of white dwarf matter is different from neutron stars (which mainly consists of neurons...)?


Is there a good reason to use "printf" instead of "print" in java?

I haven't had the chance to take any serious low-level programming courses in school. (I know I really should get going on learning the "behind-the-scenes" to be a better programmer.) I appreciate the conveniences of Java, including the ability to stick anything into a System.out.print statement. However, is there any reason why you would want to use System.out.printf instead?   Also, should I avoid print calls like this in "real applications"?  It's probably better to  to print messages to the client's display using some kind of UI function, right?


Sex worker student offering her (lawful) services

One of my students is an escort/stripper and she has offered me (and other faculty in my department) her "services". I am pretty sure my initial reaction of "thanks for letting me know, now can you answer the question about how to calculate the standard deviation", may not have been the best reaction. The offers have continued. My head of school is aware of the issue, and has asked if I want him to do anything.  Is the student doing anything wrong by offering her services to me? For what it is worth, prostitution is legal in the UK. Is this any different then a student telling me she works in a restaurant?  What is the correct response in a situation like this?


Camera motion tracking: "Unable to reconstruct" due to "POINT BEHIND CAMERA 1"

I am doing a very simple camera motion tracking, and I almost always get the errors: E1227 07:10:20.242158  6528 intersect.cc:159] POINT BEHIND CAMERA 1: 01.12694e+07 00000-502884 -2.22473e+07 E1227 07:10:20.244158  6528 intersect.cc:159] POINT BEHIND CAMERA 1: 01.12479e+07 -1.40083e+06 -1.93429e+07 E1227 07:10:20.246158  6528 intersect.cc:159] POINT BEHIND CAMERA 1: 016253.3 -19688.9 -87439.6 Unable to reconstruct position for track #2 'Track.002' Unable to reconstruct position for track #3 'Track.003' Unable to reconstruct position for track #4 'Track.004'  like this:  The video is simple; little movement and all the tracking points are visible from start to end. Only 8 points so far, I wanted to keep it simple to understand the errors above somehow. First frame:  Half way:  Last frame:  The blue/red lines all look good to me; none loose track, they keep on point. If I check the "Tripod" on the Solve tab, it works, but I get a huge error (Solve error: 11.62 px), which also is very odd to me. If I now change the "Sensor width" to 16.000 and "Focal length" to 17.00 (which is what I think that the Huawei P30 has), then the error just disappears, but I still get a solve error of 13.79.  Changing "Sensor width" and "focal length" resolves this error? But why? Im not even sure that the numbers I entered are correct.


What does someFunction(args)(moreArgs); do in JavaScript?

What does:  someFunction(args)(moreArgs);   Do in JavaScript?  I have a following working piece of code from the :  app.get('/login', function(req, res, next) {     passport.authenticate('local', function(err, user, info) {         if (err) { return next(err); }         if (!user) { return res.redirect('/login'); }         req.logIn(user, function(err) {             if (err) { return next(err); }             return res.redirect('/users/' + user.username);         });     })(req, res, next); });   In this case passport.authenticate is being called with args (the String local and a Function) then afterwards (req, res, next) exists.  In otherwords:  someFunction(args)(moreArgs);   This isn't an IIFE - there's no () around the function being ran. What is it?


We have created a  where children can learn Vegetables and Fruits. When the child answers a question they receive a notification to tell them whether they got it wrong or right.  My opinion is that the capitalization of the letters should not be in sentence case, so for example,       Wrong Answer - Try Again    is incorrect in my opinion. I think it should be       Wrong answer - try again    i.e. written as a normal sentence.  Is there a particular way it should be?  For reference purposes, here is the game just in case my question does not make sense. Click on a vegetable to see the message.


How do I lower the \widetilde accent, i.e., move it closer to the variable?

I sometimes find that the \widetilde accents sits too high above the math letter it is applied to. An example:    To me it looks as if the first tilde is sitting just in between the two lines; it is not visually attached to the "B". As the second "B tilde" shows, I did manage to produce a version where the \widetilde is lowered, but this is an ugly hack using \textcolor:  \rlap{\raisebox{-0.1ex}{$\widetilde{B}$}} \rlap{\smash{\textcolor{white}{\rule[-1ex]{2em}{2.7ex}}}} B   What I'm doing here: I lower the whole \widetilde{B}, then I erase the "B" by some (manually adjusted) white box, and finally I typeset the "B" that is seen in the output. Of course I have this wrapped in some macro, but this macro does not work for small letters such as "m", which is due to the white box.  The more straightforward attempt  \rlap{\raisebox{-0.1ex}{$\widetilde{\phantom{B}}$}}B   does not work as the output shows: the tilde in  is too far to the left. The reason for this is that TeX handles accents over single characters differently, using the \skewchar of the font, and \phantom{B} is not a single character. Moreover, in the version \tilde B I find the tilde too small: .  One of the problems of my solution is that it doesn't render properly when I view the dvi file in Yap. Does anyone know a better solution to lower the \widetilde?  EDIT:  TH's first solution works rather well. It has the only drawback that it does not lower the \widetilde over small letters such as "m". However, this is not a big deal since in this case the tilde does not look as if it is sitting in between two lines. I came up with an answer that does lower the \widetilde over "m", but that has other major problems. TH's (rather involved) second solution fixes most of these problems. Great work!


Are Guids guaranteed to be unique on creation?

I've been developing a WCF Service where clients logon with their guid that they obtain when logging in to the client and the guid gets registered at the WCF Service. But every once in a while... about almost everytime I logon with the same user login. The guid from user 'x' gets re-used..  This is the code:  public void Logon(ReceiveClient rc, string name)     {         try         {             inst = new InstanceContext(rc);             DMSNotificationClient = new DMSCSSendServiceClient(inst);              var ci = Guid.NewGuid();             ClientId = ci;              LoggedOnSince = DateTime.Now;              DMSNotificationClient.Logon(name);              ReceiveMsg += OnReceiveMsg;             FolderChange += OnFolderChange;          }         catch (Exception ex)         {             var dmsEx = new DmsException(ex);             DmsException.WriteErrorsToLog(dmsEx);         }     }   After some analyses of my C# Code I'm asking you this question:  Can I say that a GUID is NOT unique?


As GM, how do I deal with a player who makes a "do everything" build?

I have made a couple of builds that do everything, and seen several more as both a GM and as a player. These are builds that go beyond powerbuilding, and into the realm of taking over for the entire party. I'm not talking specifically about casters that do everything via magic, but rather a wider variety of builds designed to truly do everything. They cast, fight, tank, heal, and have the potential to take over entire campaigns. They have every skill, they need no party, and they don't even have the excuse of being specialized in something as generalized as "arcane casting."  Just as a few examples, I have seen an alchemist build that gets insane AC, heals, trapfinds, and has most skills in the book. On it's own, it's a monster. I have also personally created a Bard/Arcane Trickster build that gets high-level Sneak Attack, near-full Bard casting, skills for days, trapfinding, and decent physical combat potential.  As a GM, in your experience, how should I deal with players who insist on playing something that has no need for any other character in the party, in such a way that it becomes an actuality? What should I recommend that they do, other than "play a different character," so that they get to play the character they want to play and don't over-power the party?  In addition, if there are any over-powered builds/abusable mechanics in this vein that you would like to share for other GMs to be cautious of, that would be appreciated. Yes, we are aware that Wizard 20 is capable of the above in some way or another, but there are other abusable classes/builds.


Permission denied (publickey) error right after generating the SSH keys

I know this question might have been asked before But I still cannot really find the answer, and the answer in my case should be simple.   So what have I done is in my ECS server I created a new user and gave it sudo privilege by assigning it to the sudo group. Then I change some of the sshd_config parameter:   change port from 22 to another PermitRootLogin from "yes" to "no" PasswordAuthentication from "yes" to "no"   And then I generate SSH key by ssh-keygen -t rsa and copy it to the authorized_keys by ssh-copy-id user@ipAddress  and then I restart the server, ssh login to the server and get the Permission denied (publickey) error.  In the server /home/user/.ssh folder lies authorized_keys, id_rsa.pub and id_rsa three files. But in my local machine .ssh folder there is no key file.   So where is the problem?


Finding a conformal map from the intersection of two regions to a unit disk

I'm trying to solve a problem which asks me to find a conformal mapping from the intersection of $\{z\in \mathbb{C}: |z-i|< \sqrt2$  with $|z+i|>\sqrt2\}$ onto the open unit disk.  I'm really new to these and I'm a bit lost because this doesn't resemble the examples I've seen so far.  Obviously the disk and the other region intersect at $±1$, but I have no idea how to go about using this to find the result.  As I said, I haven't really done many examples of conformal maps so I'd really appreciate if you could help walk me through this example.


Is there a symbol for the first n natural numbers or the natural numbers up to n?

This seems useful but I can't find anything like it.  For example, I might want to say that $\mathbb{N}_{7} = \{ 0, 1, 2, 3, 4, 5, 6 \}$ or $\mathbb{N}_{7} = \{ 0, 1, 2, 3, 4, 5, 6, 7 \}$. Is some sort of notation like that accepted?


How to give Apache permission to write and execute in /usr/local/

I need some opinion here. What is the best method to give apache permission to create folder inside my /usr/local/ ?  Currently i'm doing apps that need the apache to create folder for each user inside it. But i dont think it possible, unless we create new group and change ownership and access to it. Is it right?  I need to know how it can be done.  Thanks


How would the shield gate have “regenerated”?

According to the novelization of Rogue One, the destruction of the shield gate on Scarif was only temporary.  The TIE fighters would concentrate on his flagship once the Empire recognized his intent. But in truth, he didn’t need to hold out long. The shield gate would regenerate swiftly enough; Rogue One’s window of opportunity to transmit would be narrow, and if it closed there would be no other. Rogue One: A Star Wars Story  However, in the film, it appears to have been quite thoroughly destroyed:  How would the gate have recovered from this massive damage and “regenerated”?


Trying to figure out if you have integral domains A and B that are isomorphic then their respective field of fractions,F and K, are also isomorphic by $\theta(ab^{-1})=\theta(a)\theta(b)^{-1}$. How can you $\theta$ is an isomorphism?  For one-to-one I figure show ker$\theta$=0 and use pigeonhole to show onto but not sure.  And for addition  would showing $\theta(ab^{-1} + cd^{-1}) = \theta(ad+bc)(bd)^{-1})$ be on the right track.  Any help appreciated.


Email Validation in Registrraion Form in javascript

I have One Register-form for creating Account.In Email Field How Can i Check Enter Email is Real Email Id or Fake Email Id without Sent Any Email.And Also when User Leave The Field Validation will be start.Any idea please Share me....


Bounded variation implies Borel measurable

Suppose that $f\colon[a, b] \to \mathbb{R}$ is a function of bounded variation. Show that $f$ is Borel measurable.  I was wondering if I could get a hint.


How to maximize Macbook pro retina's battery life when working with AC power?

I'm working 95% of my time with AC power and Thunderbolt Display. Since macbook pro retina's battery are no longer easily switchable I'm concerned about it's life and would like to maximize it. Before macbook retina I used to charge the battery to 50%, then after removing it I used the macbook without battery on AC power. But it's no longer possible.   I googled a little but didn't find a clear guidance about how to use your macbook mainly connected to AC power and not doing damage to your battery.  From what I know :   Full discharges should be avoided. Keeping you battery charged to its maximum for too long time is also bad. Try to keep charging cycles as low as possible. It's battery life (macbook pro retina battery is expected to keep 80% of its charge after 1000 charging cycles).   I try to disconnect AC power once a week until battery indicator goes down to approximatively 75% and then I connect back the AC to charge it to 100%. I don't know if it's the best steps to maximize the battery life but I think it's much better then to keep it all the time connected to the AC power.  What do you think. How to preserve battery life working on AC power ?


Why Are My Random List Items Always Identical?

I have a list and then two randomly selected items from them.  But those two items are always the same. Why?  \documentclass{article}  \usepackage{pgf} \usepackage{pgffor}  \pgfmathsetseed{\number\pdfrandomseed}  \newcommand{\InitVariables} {% \pgfmathdeclarerandomlist{List}{{2}{3}{4}{5}{6}{7}{8}{9}} \pgfmathrandomitem{\VarA}{List} \pgfmathrandomitem{\VarB}{List} }    \begin{document}   ATTEMPT ONE \InitVariables  Variable A is \VarA .  Variable B is \VarB .   ATTEMPT TWO \InitVariables  Variable A is \VarA .  Variable B is \VarB .  ATTEMPT THREE \InitVariables  Variable A is \VarA .  Variable B is \VarB .  \end{document}


I'm learning bash code and today I'm studying   the command grep.  if I run   $ ps -fU user | grep thunderbird   terminal shows:  user  17410     1  0 10:09 ?        00:00:20 /usr/lib/thunderbird/thunderbird user  18990 15896  0 12:25 pts/1    00:00:00 grep --color=auto thunderbird   But if I run:  $ ps -fU user | grep [t]hunderbird   terminal shows:  user  17410     1  0 10:09 ?        00:00:20 /usr/lib/thunderbird/thunderbird   why? I read the guide but I don't understand.


I started talking to this sugar daddy for a week. But we barely talk much... he said he would help me with ALL my bills. He only wants to see me 1-2 a month. I told him my bills. And he said he’ll put his credit card in my account in autopay to my phone bills. I don’t have credit card so he asked my username and password so he could check deposit money into my bank account...I know he helped me but I’m still hesitant to give out my bank info but maybe he’s serious in helping ? He’s not pressuring me or keep hitting me up about it.


How to detect that arrow key is pressed using C under Linux or Solaris?

What is the best way to detect in a C program that arrow key is pressed under Linux or Solaris?  As I know there is no standard C function that can do it. I don't want to use int86 function. I need to do it in a portable way.  Edit: I am asking about console applications.


I want to send the mail to multiple recipents with varying body content each user will have different content . This is the code I used for sending, but I cannot send to multiple users.   $to = 'abc@gmail.com,test@gmail.com';   drupal_mail('mimemail', 'testing', $to, language_default(), $params, $from = NULL, $send = TRUE);


The following Q&A is based on an answer I wanted to give for , but since a radical edit of the question, my answer does no longer fit, so I'm going to post it as a new question, in the hope it might be useful for someone else.   How to uncover \footfullcite step by step?


Is the Ubuntu which will be downloaded from the torrent link (given on this website) the full version that comes pre-installed on some laptops or will I have to pay some money to get it activated or for its key?


Inquiry re ETA visa to Australia without reference number. Is my visa valid?

I asked a travel agency to apply an ETA visa for Australia for me. After they processed it, they gave me a note that I was approved for ETA visa. The details in the note that they gave me are expiry date, number of entries, my passport details, type of visa and status (can work or not). There was no reference number.  Is my visa valid? Need to know as soon as possible because I am leaving next week. Please answer me....thanks.


"Invited them for lunch" vs "invited them to lunch?"

What's the correct form?  Example sentence:     He explained that his professor had invited his lab for/to lunch.


Here's the code for the query:  \documentclass[12pt,twoside]{article} \usepackage{amsmath} \usepackage[makeroom]{cancel} \usepackage{amssymb} \usepackage{amsthm} \usepackage{amsfonts} \begin{document} \[ \Longrightarrow \frac{\displaystyle \partial v^*}{\partial \gamma} = \frac{\frac{\partial \beta}{\partial \gamma}}{\frac{\partial \alpha}{\partial v^*} - \frac{\partial \beta}{\partial v^*}}. \] \end{document}   The fractions that appear in the numerator and the denominator on the right and left hand sides are smaller in size. How can I make them comparable in size to the one on the left side, which is of normal size?


I am trying to surround div with position: absolute by text. Always text going under div.  CSS which I am using:  .all {     display: block;     width: 250px;     min-height: 180px;     height: auto;     position: relative;     background: #fa65fc; } .abs {     position: absolute;     top:  80px;     left: 200px;     float: right;     width: 50px;     height: 100px;     background: #4542df; }   Two divs:

ABS
 Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum
   Here is link to:   I would like to do something like this:    Thanks in advance.


I have multiple objects with x and y values,  var object = new Object();      object.one = new Object();           object.one.x = 0;          object.one.y = 0;      object.two = new Object();          object.two.x = 1;          object.two.y = 1;   How would you determine which object has an x and a y that = 1?  You could pass is an x and y value to a function.  function = function(x,y) {     // code to find which objects x and y = parameters };


I would like to disable all attachment pages completely. I Googled it, but there's just information on . That's not what I would call an elegant solution. Why introduce unnecessary permalinks that redirect to the homepage? Couldn't it be disabled completely?


A few days I was working on a new feature on a form.  The photo uploader on the form only accepts jpegs, jpgs, and png files.  I went to upload a photo on my desktop and accidently selected a PHP file with a ~ at the end of the file.  THe ~ in the file name tricked the form into thinking its a legit file.  After I found this vulnerability I wanted to show my boss.  However I wanted to show him a more realistic scenario of the dangers of this issue.  So I went to Github and found a repository for a php backdoor.    I saw it had 20 stars so I quickly skimmed the code and cloned it without double thinking.  I then uploaded it to the server to show my boss.  I then visited the file in the browser example.com/backdoor.php .  I then deleted it after my boss freaked out.  The next day I checked the issues on the GitHub and someone says the backdoor file I uploaded on the server has a backdoor.  However I am not sure if the person who posted the issue is just trying to trick people into going to a link.    I have been panicking for the past few days on what to do and going through the code looking for what the guy is claming in the issue.  I am very concered with the code from lines 3764-4002.  It looks encrypted and I can't figure out what it is.  Am I comprimised?  I also downloaded this on localhost.    Please help I don't know what to do.  AND YES I KNOW IT WAS STUPID FOR ME TO DOWNLOAD THAT AND UPLOAD IT.  I was not thinking it through.


Creating Pie Chart with radius based on another field?

I have to symbolize my ares polygon feature class and create pie Chart based on the following values in ArcGIS 10.2 for Desktop:  Area    Tds_Calc    Free_Chlorine   Ph    Fluoride  Turbidity   Failures ========================================================================  Area A  39.87           23.47       5.14     0          2.57     5  Area B  28.54           54.88       10.24   3.41        1.95    19  Area C  72.05            5.12        0.39   0.79        1.57    12  Area D  1.61             61.29       8.06   14.52       1.61    25  Area E  15               66.67       3.33      5        6.67    30  Area F  55.56            27.78       16.67     0         0       9   Pie Chart will be created based on the 5 fields and the last field, i.e. "Failures" should be used as radius of the pie chart. Thus, we will have size of the Pie based on the "Failures" and rest of the fields will be depicting the share of parameters.  How can I achieve this task?


Notepad++ replace dots/punctuations that are alone not beeing surrounded by numbers

I would like to find dots/punctuations not surrounded by any numerics or alphanumerics (in other words surrounded by nothing) and replace these with nothing using Notepad++ and regex.  I tried using  (?<![a-zA-Z0-9]).(?![a-zA-Z0-9])   but it replaces all the numbers surrounding each dot with nothing.  How can this expression be adjusted appropiately for use in Notepad++ ?


How to export procedural material in gltf/glb format?

I am playing around procedural rust material in Blender and want to apply the material to my sword model so it looks rusty and old to further export it as glb or gltf this is my node setup  The required result that I am looking for  The resulted gltf export  I have tried baking the material into a texture file and then exporting still same result.


Quantum Zeno effect and unstable particles

Is it possible to increase indefinitely the lifetime of unstable particles by applying the ? Is there a bound from theoretical principles about the maximum extension one can get in a unstable energy level in general from continuous measurement alone?


Find square with latitude and longitude for given lat and lng and distance

I have the coordinates of some point, lets say lat and lng,  I want to find the latitude and longitude of top left and bottom right corners of the square, whose sides are located k kilometers from the initial point.


I'm a beginner in Java.  Please suggest which collection(s) can/should be used for maintaining a sorted list in Java. I have tried Map and Set, but they weren't what I was looking for.


Change font only for verbatim part of the document

I need to set a certain monospace font only for the verbatim parts of the document. How can one do this?  For example, I understand that the commands  \usepackage{lmodern} \renewcommand*\familydefault{\ttdefault} %% Only if the base font of the document is to be typewriter style \usepackage[T1]{fontenc}   will set the font for the entire document, not solely for the verbatim part.


An example of a group, a subgroup and an element, satisfying a given condition.

Is there a group $G$, a subgroup $H$ and an element $x$, such that $xHx^{-1} \subset H$, but  $xHx^{-1} \neq H$?  Thanks in advance.


How to query data range including data formatting (color, font) in Google sheets?

How to modify this formula to make the result get the data with its original color & font formatting. =query(Sheet1!A1:D,"select A,B,C,D where A is not null",0) Lets say I want only column D to be in the new tab with its original color format.


New to Ubuntu, how do I get drivers for my USB WiFi LAN Adapter?

I reformatted an old desktop of mine to boot Ubuntu 13.04, which I will be using as a mini-server to host VPSes. It will become a headless server that I will be putting in my closet when I finish configuring it. I will simply use VNC software to connect to it when need be.  The desktop does not have a built-in WiFi adapter, so I purchased a Linksys AE2500 Dual-Band Wireless-N USB Adapter. I bought this back when the desktop ran Windows 7. I was wondering where I should start to find any drivers, or anything really that will allow me to get this adapter working on Ubuntu. Note there is no internet connection to the desktop, and I can't connect it with an Ethernet cable. I do have another laptop with internet if I need to download and transfer any files via flash drives.  I am extremely inexperienced with Linux and this project is one way I'm trying to learn about it.


Making all numbers in a list 3 digit numbers

I have a list a:  a = [45,2, ... ,123,98]   How can I convert all numbers to three-digit numbers by adding zeros in front of one or two-digit numbers? This would create a new list like:  b = [045,002, ... , 123,098]


Story About Contact with an Alien Race That Lives on a Different Time Scale

I remember a few months ago looking at a story about humans arriving on a planet and finding a microscopic alien race. This microscopic alien race lived on a different time scale where they aged a lot faster than the humans. A short time passes for the humans and by then, the aliens are technologically advanced enough to make contact but then decide not to give any information about technologies the humans haven't discovered yet. Hopefully anybody has an idea as to who the author is and what the title is?


What is the difference between "data" and "information"?

So I've always assumed that data and information are the same thing, however, someone I know told me that there is a difference between them, but neglected to tell me said difference. Could someone please tell me the difference Thanks. (PS. Sorry for asking a stupid question)


What is the meaning of "Call it a day/night". I have heard people saying "I am calling it a day". I tried to find out the meaning in dictionaries, but could not. Please let me know your answers.


I'm currently on Ubuntu version 14.04. How can I update not to the newest version but to 16.04?

I know 17.10 is the latest. I'm on 14.04. I want to go to 16.04 not 17.10. All tutorials I see online tell how to update to newest version.  Update 1: That answer is about servers. I'm talking about Ubuntu versions. That answer clearly tells u to make sure ur on the latest versionof ubuntu, whih I am not.


I tried following their guide for installing  for Ubuntu 18 but ran into a few issues. After entering the first command: apt update && apt -y install ca-certificates wget net-tools  I'm hit with the following errors. Reading package lists... Done E: Could not open lock file /var/lib/apt/lists/lock - open (13: Permission denied) E: Unable to lock directory /var/lib/apt/lists/ W: Problem unlinking the file /var/cache/apt/pkgcache.bin - RemoveCaches (13: Permission denied) W: Problem unlinking the file /var/cache/apt/srcpkgcache.bin - RemoveCaches (13: Permission denied)  I then tried adding "sudo" in front of the original command it seems to have fixed one of the problems but still receive errors at the end. Hit:1 http://ca.archive.ubuntu.com/ubuntu bionic InRelease Get:2 http://security.ubuntu.com/ubuntu bionic-security InRelease [88.7 kB] Get:3 http://ca.archive.ubuntu.com/ubuntu bionic-updates InRelease [88.7 kB]    Get:4 http://ca.archive.ubuntu.com/ubuntu bionic-backports InRelease [74.6 kB]  Get:5 http://ca.archive.ubuntu.com/ubuntu bionic-updates/main i386 Packages [586 kB] Get:6 http://ca.archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages [740 kB] Get:7 http://ca.archive.ubuntu.com/ubuntu bionic-updates/universe amd64 Packages [1,007 kB] Get:8 http://ca.archive.ubuntu.com/ubuntu bionic-updates/universe i386 Packages [980 kB] Fetched 3,564 kB in 6s (601 kB/s)  Reading package lists... Done Building dependency tree        Reading state information... Done 24 packages can be upgraded. Run 'apt list --upgradable' to see them. E: Could not open lock file /var/lib/dpkg/lock-frontend - open (13: Permission denied) E: Unable to acquire the dpkg frontend lock (/var/lib/dpkg/lock-frontend), are you root?  I'm not sure what to do from here. Any advice?


In spite of English the German language does not have Present/Past Progressive, although both languages have the same root. When and why did the progressive tenses develop and became part of the English language?    Note: this is not a duplicate of  because that one does not explain WHY (in spite of German) it has happened as requested here.


Check whether files in a file list exist in a certain directory

The runtime arguments are as follows: $1 is the path to the file containing the list of files $2 is the path to the directory containing the files What I want to do is check that each file listed in $1 exists in the $2 directory  I'm thinking something like:  for f in 'cat $1' do if (FILEEXISTSIN$2DIRECTORY) then echo '$f exists in $2' else echo '$f is missing in $2' sleep 5 exit fi done   As you can see, I want it so that if any of the files listed in $1 don't exist in the directory $2, the script states this then closes. The only part I can't get my head around is the (FILEEXISTSIN$2DIRECTORY) part. I know that you can do [ -e $f ] but I don't know how you can make sure its checking that it exists in the $2 directory.


Prove algebraically or otherwise:  $$\sum \limits_{r=0}^n {2r \choose r} {2n-2r \choose n-r} = 4^n $$  where ${n \choose r}$ denotes the usual binomial coefficient. I think there is a combinatorial proof using path counting arguments, but I haven't been able to find it.


Render partial from different folder (not shared)

How can I have a view render a partial (user control) from a different folder? With preview 3 I used to call RenderUserControl with the complete path, but whith upgrading to preview 5 this is not possible anymore. Instead we got the RenderPartial method, but it's not offering me the functionality I'm looking for.


Wildcard SSL certificate for second-level subdomain

I'd like to know if any certificates support a double wildcard like *.*.example.com? I've just been on the phone with my current SSL provider (register.com) and the girl there said they don't offer anything like that and that she didn't think it was possible anyway.   Can anyone tell me if this is possible, and if browsers support this?


Imagine you were on a spherical spacecraft that had equal mass all the way around and you were deep in space, away from the gravitational pull of any planetary bodies or stars. If you released a marble at arm's length, would it be gravitationally pulled toward your body? If you flicked it in one direction, would it begin to orbit you? (If a marble is too big, then maybe a grain of sand?)


If $v_{contact,road}$ in rolling motion is zero, how the contact point still manages to move forward?

If velocity of contact point of a rigid body performing rolling motion w.r.t road is zero then how the point gets delocalised from its initial position after some time?  My textbook says, At any instant a rolling sphere may be considered to be in pure rotation about an axis through the point of contact.This axis translates forward with the speed equal to the speed of its centre.  The above statement makes me more confused as my same textbook says that $v_{contact,road}$ is zero and simultaneously it says that the axis passing through the contact point translates forward.  EDIT  My question is somewhat different from  as I also want to know that how the axis passing through the point of contact translates forward if the  $v_{contact,road}$ is zero.


Intuition behind unit hypersphere/n-ball volume

Obviously the volume of a unit hypercube is always $1$.  I know that the volume of a unit hypersphere is given by: $$ \dfrac{\pi^\frac{d}{2}}{\Gamma\Big(\dfrac{d}{2} + 1\Big)} $$ which .  Why should it be this way? I can't get my head around why volume should increase with dimension only to a point.


I wrote something in LyX and then converted that into a tex file. But when I convert the tex file into a pdf, a huge gap is produced between the last sentence of a paragraph and the next section title like here:     In addition, a large gap is created between one image and another paragraph like the following:     I am pasting here the preamble set by LyX by default:  \documentclass[12pt,twoside,english,refpage,intoc,bibliography=totoc,index=totoc,BCOR7.5mm,captions=tableheading]{article} \usepackage{lmodern} \renewcommand{\sfdefault}{lmss} \renewcommand{\ttdefault}{lmtt} \usepackage[T1]{fontenc} \usepackage[latin9]{inputenc}   \usepackage{geometry}   \geometry{verbose,tmargin=1in,bmargin=1.25in,lmargin=1in,rmargin=1in,headheight=1in,headsep=1in,footskip=1in} \setcounter{secnumdepth}{2} \setcounter{tocdepth}{2} \setlength{\parskip}{\medskipamount} \setlength{\parindent}{0pt} \usepackage{color} \usepackage{babel} \usepackage{array} \usepackage{booktabs} \usepackage{float} \usepackage{amsmath} \usepackage{graphicx} \usepackage{setspace} \usepackage[authoryear]{natbib} \usepackage[unicode=true,bookmarks=true,bookmarksnumbered=true,bookmarksopen=false, breaklinks=false,pdfborder={0 0 1},backref=false,colorlinks=true] {hyperref} \hypersetup{pdftitle={The LyX User's Guide},  pdfauthor={LyX Team},  pdfsubject={LyX},  pdfkeywords={LyX},   linkcolor= black, citecolor=black, urlcolor=blue, filecolor=blue, pdfpagelayout=OneColumn, pdfnewwindow=true, pdfstartview=XYZ, plainpages=false} \makeatletter %%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Textclass specific LaTeX commands. \newlength{\lyxlabelwidth}      % auxiliary length    Any suggestions on how to reduce those gaps shown above? Thanks in advance.


Viterbi training vs Baum-Welch algorithm

I'm trying to find the most probable path (i.e. sequence of states) on an HMM using the Viterbi algorithm. However, I don't know the transition and emission matrices, which I need to estimate from the observations (data).  To estimate these matrices, which algorithm should I use: the Baum-Welch algorithm or the Viterbi Training algorithm? Why?  In case I should use the Viterbi training algorithm, can anyone provide me a good pseudocode (it's not easy to find)?


How do I force a column-break in a two-column document?

Similar to  I want to force a column-break in a two-column document.  \columnbreak   seems to be undefined without the multicol package.


Layout  <?xml version="1.0" encoding="utf-8"?>   <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="wrap_content" android:layout_height="match_parent" android:id="@+id/llist" tools:context="com.android.parteek.contentprovider.Main2Activity">  <android.support.v7.widget.SearchView android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/serch"> </android.support.v7.widget.SearchView>  <ListView     android:id="@+id/list"     android:layout_width="match_parent"     android:layout_height="match_parent"     tools:context="com.android.parteek.contentprovider.Main2Activity">  </ListView>  </LinearLayout>   Code  package com.android.parteek.contentprovider;  import android.content.ContentResolver; import android.content.DialogInterface; import android.content.Intent; import android.database.Cursor; import android.support.v7.app.AlertDialog; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.support.v7.widget.SearchView; import android.util.Log; import android.view.Menu; import android.view.View; import android.widget.AdapterView; import android.widget.ListView; import android.widget.Toast;  import java.util.ArrayList;  public class Main2Activity extends AppCompatActivity implements AdapterView.OnItemLongClickListener, SearchView.OnQueryTextListener { ListView l; ArrayList<Bean> arrayList; UserAdapterr userAdapterr; ContentResolver contentResolver; SearchView searchView; Bean b,b1; int pos; void views(){     l=(ListView)findViewById(R.id.list);     searchView=(SearchView)findViewById(R.id.serch);  } @Override protected void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     setContentView(R.layout.activity_main2);     views();     contentResolver=getContentResolver();     retrieve(); } @Override public boolean onCreateOptionsMenu(Menu menu) {     getMenuInflater().inflate(R.menu.searchmenu,menu);     searchView=(SearchView)menu.findItem(R.id.search).getActionView();    searchView.setIconifiedByDefault(true);    searchView.setOnQueryTextListener(this);    searchView.setQueryHint("search.....");      return super.onCreateOptionsMenu(menu); }   @Override public boolean onQueryTextSubmit(String query) {     return false; }  @Override public boolean onQueryTextChange(String newText) {     return false; } }   Error   java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v7.widget.SearchView.setIconifiedByDefault(boolean)' on a null object reference                                                                                at com.android.parteek.contentprovider.Main2Activity.onCreateOptionsMenu(Main2Activity.java:147)


Consider a scenario where an elevator is moving up with constant acceleration 'a'. If a stone is thrown from it will the stone also possess an acceleration 'a'?  Because i know that if we throw a stone from an elevator moving with uniform velocity the stone also acquires that velocity,so what will be the case with uniform acceleration.


I need to prove that if $X$ and $Y$ are iid $N(0,1)$ random variables, then $U=\frac{X Y}{\sqrt{X^{2}+Y^{2}}} \sim N(0,1 / 4)$. I know that:  $U=\frac{\left(\frac{X+Y}{2}\right)^2-\left(\frac{X-Y}{2}\right)^2}{\sqrt{X^2 + Y^2}}$; $\left(\frac{X+Y}{2}\right)^2, \left(\frac{X-Y}{2}\right)^2$ follows a chi-squared distribution with parameter 1; $X^2 + Y^2 \sim \chi_2^2$ follows a chi-squared distribution with parameter 2. But I don't know how to move forward from this or even if this is the right path.


How to calculate age (in years) based on Date of Birth

Problem: I have a table that list the person DOB.  I have a field (called Person_DOB) that I can use to grab the person DOB from the database. I would like to grab the person year they were born and compare it with the current year we are in.  Ex. 1988-09-26 00:00:00.000  I have a field that I can call that contains the DOB of the person. How can I covert that to a date and calculate their age using C#?  I have tried the following but it appears to not work:  <% int now = int.Parse(DateTime.Now.ToString("yyyyMMdd")); int dob = int.Parse("Person_DOB".ToString("yyyyMMdd")); int age = (now-dob) / 10000; Response.Write(age); %>   But I am getting invalid argument error. What am I doing wrong?


Selection of items in a grid across pages

Would you expect when making selections across multiple "pages" in a grid or other list style control that it would remember your selections? Would you expect it to forget your selections the moment you page to the next set of data?  Along the same lines, if said control did remember user selections across pages would you expect actions performed against selected items to apply only to those currently in view? Or would you expect it to be applied to all items? Maybe this is a case-specific problem but I'm just interested in hearing the community's thoughts.


NullPointerException: Attempt to invoke virtual method 'java.lang.String com.zopim.android.sdk.model.VisitorInfo.getEmail()' app is forced close

I'm integrating Chat zendesk for my android app & I got this error NullPointerException: Attempt to invoke virtual method 'java.lang.String com.zopim.android.sdk.model.VisitorInfo.getEmail()'.  Any one know about it please let me know the solution. Thank you in advance.


Why does Linux not allow `cat`ing a directory?

I read in The Design of the UNIX Operating System that directories are files containing the names of each file they contain. So I tried cating one on my Mac, and it resulted in an error: cat: ./: Is a directory  But I then tested it in System 7 UNIX, and it worked.  .  Why does this not work in modern operating systems? Is a directory no longer a file, or did someone decide we shouldn't be able to read them?


Is the usage of 'this' correct in this sentence?

Is it okay to say 'There was this mesmerizing, melancholic music everywhere filling the hearts with wonder and awe.'? Is it right to use 'this' in this context or is it considered colloquial usage?


How to connect to Android through SSH over 3G/4G public IP?

I am having an Android device and I want to connect in via 3G/4G and I am getting connection refused.  Any ideas how to do that?


If we expand $$ (x_{1}+x_{2}+...........+x_{k})^{n} $$ How many terms will be there once we collect terms with equal monomials?   What is the sum of all coefficients?  I literally have no clue how to start it.  I am relating it to multinomial coefficient $$\frac{n!}{n_1!n_2!\dots n_k!}$$  but I don't know how to proceed.


Steps to take to improve email deliverability

Successfully delivering email to my clients is a pretty high priority at my company. We are of course fully opt-in, paid clients, no possibility of spam, the whole thing. The information we email is specifically requested from us by the recipient.  We have done some of the easy stuff like setting up  on our outgoing mail servers.  What other steps can we take to ensure that our email goes through, in terms of email server setup and configuration ( similar to SPF, etc )  Alternatively, are there 3rd party email services that we can pay for that already manage these issues?


Refresh LWC Component from AURA Component - Error : - 'forceRefreshInitiated' of undefined

I'm trying to refresh LWC Component from AURA component. I need help in resolving the below error as i'm not able to figure out the issue here. Error :-  Uncaught Action failed: c:QuoteLineItemsAuraComponent$controller$closeModelAddProduct [Cannot read property 'forceRefreshInitiated' of undefined]  Aura Component Code is as follows :-   <c:addProductsParentComponent style="padding:0px" recordId="{!v.recordId}" oncancelAndClose="{!c.closeModelAddProduct}">         </c:addProductsParentComponent>   <c:quoteLineItemRelatedList aura:id="messageBroker" style="padding:0px" recordId="{!v.recordId}"  oncancelAndClose="{!c.closeWindow}">     </c:quoteLineItemRelatedList>   Aura JS Controller code is as follows :-    closeModelAddProduct: function(component, event, helper) {   // for Hide/Close Model,set the "openAddProductModal" attribute to "Fasle"   component.find("messageBroker").forceRefreshInitiated();      // refresh the view     //$A.get('e.force:refreshView').fire();   component.set("v.openAddProductModal", false);   component.set("v.showButtonDiv", true);  },   LWC JS code is as follows :-   @api  forceRefreshInitiated() {     console.log('forceRefreshInitiated');     refreshApex(this.refreshTable);   }   TIA, Sunil


What's this round medallion from the "Rise of Skywalker" trailer?

This round medallion is held by someone in the . It looks familiar but I can't place it.  Is it something from existing Star Wars lore?


How can i convert a field 1,2,3,4... to 001,002,003,004...010...?  For example   1 change to 001 2 change to 002  3 change to 003   ...  Is there any formula in field calculator?


Proving that if $0<a<b$, then $a<\sqrt{ab}<\frac{a+b}{2}<b$

In proving these inequalities, what I did was to take each of the "<" relations and prove them. Is this a valid way of proving if we have got several inequalities as in this problem?  So here is my proof by parts.    $a<\sqrt{ab}$:  Let $P$ be the set of all positive numbers. Since $a,b,b-a\in P$, we have $a(b-a)=ab-a^2\in P$, so $a^2<ab$, which implies that $a<\sqrt{ab}$. (I make a separate proof for this implication, which goes as follows: $a^2<b^2 \iff 0<b^2-a^2=(b-a)(b+a)\in P$, so $(b-a)\in P$, thus $a<b$). So this proves $a<\sqrt{ab}$.  $\displaystyle\sqrt{ab}<\frac{a+b}{2}:$  We have $\displaystyle\sqrt{ab}<\frac{a+b}{2}\iff2\sqrt{ab}<a+b\iff0<a-2\sqrt{ab}+b=(\sqrt{a}-\sqrt{b})^2$. Since $a,b$ are both non-zero, so $0<(\sqrt{a}-\sqrt{b})^2$ holds, thus, proving $\displaystyle\sqrt{ab}<\frac{a+b}{2}$.   $\displaystyle\frac{a+b}{2}<b$:  By closure under addition, $a<b \implies a+b < b+b = 2b$, dividing by $2$,  $\displaystyle\frac{a+b}{2}<b$.    Does this work? If not, where did I go wrong? Is there a much better way to show this?


Determine $L$ such that a function is continuous

Determine $L$ such that the function $f:\mathbb{R^2} \to \mathbb{R}$, defined by $$f((x,y)) = \begin{cases} \frac{\sin(xy)}{\sqrt{x^2+y^2}} & (x,y) \in \mathbb R^2/(0,0) \\ L & (x,y) = (0,0) \end{cases}$$ is continuous at $(0,0)$. I supposed that the wanted $L$ is $0$ and I used continuity( module of difference) to show that it converges to $0$, but I am not quite sure it`s the right answer. Any help, please?


drawing a tangent on a graph in pgfplots

I need to draw a tangent to a graph at time = 4, 10, 16, and 24 on this graph. How would I go about drawing a tangent on it and measuring the gradient of the tangent?  \begin{tikzpicture}[rotate=90] \begin{axis} [     width=20cm, height=14cm,     title={Investigating the affect of concerntration on rate of reaction},     xlabel={Time (s)},     ylabel={Volume Displaced (cm$^3$)},     grid style=dashed,     ymajorgrids = true,     xmajorgrids = true,     mark size = 1, ] \addplot[scatter , mark=halfcircle* , only marks , mark size=2.9pt , thick , smooth , color=orange ]     table{data/2.9-conc1.dat};  \addplot[scatter , mark=square* , only marks , mark size=2.9pt , thick , smooth , color=red ]     table{data/2.9-conc2.dat}; \legend{7:3,5:5} \end{axis} \end{tikzpicture}     Here are the results:  X   Y 2   2.8 4   11.2 6   19.8 8   28.2 10  37.4 12  45.5 14  54.4 16  63.3 18  73.0 20  82.4 22  92.1 24  103.3 26  113.2  X   Y 2   10.8 4   26.0 6   43.0 8   60.0 10  79.4 12  98.5 14  119.0 16  139.2 18  163.1 20  187.0 22  211.8 24  238.5 26  267.7


Distribution for Sum of Square Normal Variables with Arbitrary Variance

Let $X_1\sim N(0,\sigma_1^2), X_2\sim N(0,\sigma_2^2),\dots,X_n\sim N(0,\sigma_n^2)$ where generally $\sigma_1\neq\sigma_2\neq\sigma_3\dots\neq\sigma_n$. What is the distribution of the statistic $$Y = \sqrt{\sum_{k=1}^n X_k^2}?$$  The distribution for $Y^2$ is obtained by a combination of  and , but I don't know enough about characteristic functions to see if there's any easy way of incorporating the square root.


How can we consider charge to be continuous?

In electrostatics, we usually consider charge to be continuous on any body, to calculate the electric field of the body. For eg. I had proved the  taking an infinitesimal charge of $dq$ on the sphere. But we also know that charges are quantized (In terms of electrons and protons). They are finite and not infinitesimal. So is considering them continuous an approximation or is there a reason to why we can do it?


I'm using this simple code to align date ranges on a CV:  \section{I'm pretty cool}\begin{tabular}{l l} 2009--present & company 1 \\ 2011--2012 & company 2 \end{tabular}   Now this looks like this:  2009 - present   company 1 2011 - 2012      company 2   but I'd like to add a list in each of the entries, like this:  2009 - present   company 1:                    * editor 2011 - 2012      company 2                    * judge                    * jury                     * executioner   How can I achieve this? I could itemize them in a separate column, but it doesn't work inside tabular in cases like this, where I want part of "company 2" to be in that column.


![][1]  So i have this definite integral:  $$\int_{\sqrt[3]{4}}^{\sqrt[3]{3+e}}x^2 \ln(x^3-3)\,dx.$$  I thought of using integration by parts. So \begin{align} u & =\ln(x^3-3) \\[8pt] du & =\frac{3x^2}{x^3-3} \\[8pt] dv & =x^2 \, dx \\[8pt] v & =\frac{x^3} 3 \end{align}


Connecting 2.1 A charger instead of 850 mA

I have a Sony Xperia SP model with a 2370 mAh battery. The original charger I got with it was of 850 mA.  My question is can I use a charger with output of 5V-2.1A which is also from Sony?  thanks and regards


I'm somewhat confused about the nature of Time in the Matrix, but I have 3 different possibilities, all of which are neither confirmed nor denied in the trilogy as far as I can see.   Possibility 1: Time is fixed.  By saying time is fixed, I don't mean it's constantly one specific point in time, but it is always the 90s (as I know the Architect stated that the 90s were the optimum time).  The way I envisage this possibility, it goes from Jan 1 1990 to Dec 30 1999, then the next day is Jan 1 1990 again (an infinite loop).  The people of the Matrix, however, are oblivious of this.  In this possibility, humanity is in stagnation - no development of new ideas beyond those attained by 30 Dec 1999.  (This would be denied if we see that the date in number 3 exceeds 1999, as the film itself was made post 1999). Possibility 2: Time repeats itself.  Similar to Possibility 2, but instead of limiting it to the 90s, the Matrix runs from some point near the beginning of humanity (perhaps the year 0?  Your guess is as good as mine here) and runs until the war between the machines and humans erupts, then goes back to the beginning again.  Supported perhaps by Smith's statement in the first movie about Decartes being an evil genius or something. Possibility 3: Alternate timeline.  Similar to the above possibility in that time for those in the Matrix begins from some point (an unknown point in time), but continues without the war between humanity and the machines erupting - a completely alternate timeline.   I'm not claiming to be an expert on The Matrix, but I'm looking for evidence within the movies to explain how time works for those in the Matrix itself - something that I've overlooked.  (Note however: if this proves to be impossible i.e. there is no evidence to support one of these possibilities (or another one for that matter), I am willing to accept materials external to the trilogy).


Once in a blue moon, I've wanted the ability to downvote my own answer to some question.  ()  Obviously upvoting one's own posts is out of the question.  But down is different.  Voting my own answer down can help me improve the site by pushing my answer lower in the ranking than another answer with a better or more situation-appropriate alternative.  It's not something I'd do often, but I would use this feature if it were available.  If implemented, I'd expect this feature to operate just like downvotes on other user's posts.  That is:   I get a few seconds to undo the downvote;  I get to remove the downvote after an edit to the post;  I lose a point for placing the downvote (CW excepted); I lose two points for receiving the downvote (CW excepted).   If you're noticing that I'd lose 3 points for downvoting my own non-CW post, congratulations! You can add!  I can think of a couple of potential downsides to this change.  The first one may be a dealbreaker; the second is probably not that big a deal.   Strategic downvoting of oneself: since you can undo the vote after an edit, and you can always edit your own posts, someone could downvote themselves soon after posting (especially on a FGITW answer) to garner extra sympathy upvotes. Badge collecting: the Peer Pressure badge just got easier, because if you have a -2 score on an answer, just downvote and delete for an instant badge.


Should I downvote a low quality question if it's already been closed?

In general, if a bad question has already been closed (not necessarily for , but, e.g., for being off-topic), and it already has a negative vote score, is it meaningful to further add your downvote?  I see no benefit to this, I only see that you lose 1 rep for adding your downvote. Can anyone explain if there’s a point to doing so?  I don’t believe this question is a perfect duplicate of “,” because that question (which is itself a duplicate of , which does not answer my question) requests making it impossible to do so whereas my question is meant to spark discussion only, leaving users with the freedom to downvote.


How do I get past a 3-year ban from overstay with VWP?

I have an overstay with a VWP of 333 days, I had to leave the US in January 2018 but stayed until December 2018 to take care of an American citizen who has no family. I have a 3 year ban. So I had to apply for a B2 visa, I have already done this twice and both have been refused. The woman at the embassy told me that I cannot get a visa as long as the 3-year ban lasts, only after those 3 years  I can apply for a visa and a waiver. Is this true? Can I ask a waiver before I apply for a visa or do i have to wait until i have the B2? And which waiver should I ask?


Problem with IEEEtran for LaTeX Bibliography

I download latex bibliography style file from .   Sample Code:  \documentclass[twocolumn,conference,a4paper]{IEEEtran}  \usepackage{amssymb,amsmath,epsfig,latexsym,graphicx,bm,multirow} \usepackage[left = .56in, top=.75in,right=.56in,bottom=0.8in,nohead,nofoot]{geometry} \usepackage{epstopdf} \begin{document} \maketitle \bibliographystyle{IEEEtran} \bibliography{IEEEabrv,IEEE} \end{document}   The problem is that references of one column are move to other column and some moves out of page's margin. Example shown in below fig:      Please help to solve this problem.


I read many questions and answers like  and   I know wildcards are expanded by the shell before running a command and they are a feature of the shell.  Also wildcards work with those commands that can accept many arguments.  In find . -name *.rb  if we have more than one file in the current directory find will give us an error because find cannot accept multiple arguments and the ways to solve this are:  find . -name "*.rb" find . -name '*.rb' find . -name \*.rb   We escape the asterisk and prevent expansion by the shell but wildcards are a feature of the shell; when we escape the asterisk shell does not know about its meaning, and it should find a file named *.rb, so how is the asterisk being expanded in this case?


Precedence of user and group owner in file permissions

I just ran into something unexpected (for me) regarding file permissions on Linux (Arch Linux). Basically I have:   userX in groupX fileX userX:groupX ---rwx----   What puzzles me: I cannot perform any action (rwx) on fileX. Is this right? Can someone please confirm this is indeed the expected behaviour?  The only actions I can perform are mv and rm because I have write permissions on the parent directory.  The thing is, I always thought these permissions collapse on each other, starting with the most general one (other -> group -> user). In other words, if o=rwx who cares what the persmissions for group and user are? Apparently this is not the case but it doesn't make much sense to me; it seems counterintuitive. The only thing this approach seems to be useful at, is to easily exclude a very specific person / group, which doesn't seem like a smart way to go at it (imho). Besides, the owner (and group?) should be able to chmod anyway right? Any thoughts on this matter?


Guarding .h variables with #ifndef is not stopping multiple definitions. How to fix?

I am trying out standard method of guarding a .h (example:checkpgm.h) file with guard variables as follows #ifndef _CHECKPGM #warning CHECKPGM value is 0 #define _CHECKPGM 1 char a; #endif  This code is included in two files checkmain.c and checksub.c When these two files are linked I get the error message Building target: checkpgm Invoking: GCC C Linker gcc  -o "checkpgm" ./src/checkmain.o ./src/checksub.o    /usr/bin/ld: ./src/checksub.o:/home/nagesh/eclipse-workspace/multi/checkpgm/Debug/../src/checkpgm.h:18: multiple definition of `a'; ./src/checkmain.o:/home/nagesh/eclipse-workspace/multi/checkpgm/Debug/../src/checkpgm.h:18: first defined here  I am unable to understand how this is happening in-spite of guarding. I tried  Changing #define _CHKPGM  to #define _CHKPGM 1 (explicit value assignment) Similarly, #if  _CHKPGM == 0 Checking with #if defined Adding _CHECKPGM with -D flag (Undefined) Somehow standard libraries are not having this problem (stdio.h, stdlib.h); So copied their style _BEGIN_DECLS... By warning messages, it is clear that _CHECKPGM gets assigned in its first inclusion. However This value will be lost when compilation of second program begins and hence guard fails. But unable to figure out why?.  Can you folks please help us out? Thanking in advance... RaviJ checkpgm.h is included in


Why don't any USA professional leagues use promotion/relegation?

Promotion/relegation is a competition format that is often used in many countries for professional leagues as a way to have many teams participate and yet not dilute the top level of play, by only allowing the best teams to play in the highest division while leaving a path to the top open for lower teams, should they improve enough to reach it.  For example, in England, there are thousands of football (soccer) teams, in varying divisions from the Premier League (top 20) all the way down to "amateur" level. However, even teams at the lowest division could theoretically one day play in the Premier League if they were to be successful enough to reach that level.  Due to the size of the United States, it seems like this format would have been ideal here to allow teams to exist all over the country. Yet it seems like this kind of format has never been used for professional sports in the United States. Why is that?


Evaluate $\int_0^1\left(\frac{1}{\ln x} + \frac{1}{1-x}\right)^2 \mathrm dx$

Evaluate $$\int_0^1\left(\frac{1}{\ln x} + \frac{1}{1-x}\right)^2 \mathrm dx$$


APFS on external drive missing from Disk Utility

When I use  app in  to format an external drive, I do not see the new  offered as a choice of format.  Does it matter that my external drive is a  Portable External Hard Drive plugged into a  via USB-3 cable? I know APFS is optimized for solid-state storage, so does Disk Utility not offer it for a spinning-metal disk drive?  ➥ Why is APFS not offered by Disk Utility?


What does "You have requested package `foo', but the package provides `foo'." mean?

I know what this message means in general ("do not add path names in package names"), and my question is not a duplicate of , where the two names differ (by the path name). In my case the package names are really identical (without path name in both cases)!  I'm working on MiKTeX 2.9, with latest updates (I refreshed FNDB). I get this with the latest moderncv package (version 2.0), MWE:  \documentclass{moderncv} \moderncvtheme{classic} \name{Foo}{Bar} \begin{document} \end{document}   where I get  You have requested package `moderncvheadi', but the package provides `moderncvheadi'. You have requested package `moderncvbodyi', but the package provides `moderncvbodyi'.   What does trigger this warning in this case and how can I solve it? Is it a bug in moderncv? The official source on  looks fine to me.


Is the escape velocity of black hole greater than the speed of light ? If not, then why does light can't escape the black hole?

I've heard different type pf answers for this qs and not really sure which one to go for.


How prove there is no continuous functions $f:[0,1]\to \mathbb R$, such that $f(x)+f(x^2)=x$.

Prove that there is no continuous functions $f:[0,1]\to R$, such that   $$ f(x)+f(x^2)=x. $$   My try. Assume that there is a continuous function with this property. Thus, for any $n\ge 1$ and all $x\in [0,1]$, \begin{align*} f(x)&=x-f(x^2)=x-\big(x^2-f(x^4)\big)=x-x^2+\big(x^4-f(x^8)\big)=\cdots\\ &=x-x^2+x^4-\cdots+(-1)^n\left(x^{2^n}-f\big(x^{2^{n+1}}\big)\right) \end{align*}  since $f(0)=0$ and $\displaystyle\lim_{n\to \infty}x^{2^{n+1}}=0$ for any $x\in(0,1)$,it follows by the continuity of $f$ that $\displaystyle\lim_{n\to \infty}f\big(x^{2^{n+1}}\big)=0$, hence $$f(x)=x-x^2+x^4-x^8+\cdots+(-1)^nx^{2^n}+\cdots$$ for any $x\in (0,1)$  Why do I have prove that there is exists such a continuous functions $f$? Maybe  my example is wrong? Why?  if my   method is wrong,then How prove this problem ? Thank you.


How to know which program has just played sound?

At times, my computer suddenly played some annoying short sound (sounds like darrrt, seems not from the system), and it's so short that I have no idea where it comes from (and cannot capture it).  Is there any ways to find which program/process did that? (I really want to kill it!)  I am using OS X Mavericks.


How do I run a Bash command via a PY file?

The following Python script is extracted from /usr/lib/python2.7/dist-packages/Mailnag/plugins/libnotifyplugin.py  In the script, the command ('zenity --info --text="You got new mail"') is not run.  How do I make it run? I want it to run when mail_count > 0 The lines under if mail_count > 1: are run properly.  if mail_count > 0:     import os     os.system('zenity --info --text="You got new mail"')     if mail_count > 1:     summary = _("{0} new mails").format(str(mail_count))     if (mail_count - i) > 1:         body = _("from {0} and others.").format(senders)     else:         body = _("from {0}.").format(senders) else:     summary = _("New mail")     body = _("from {0}.").format(senders)   I put the following "Testing.py" script into /usr/lib/python2.7/dist-packages/Mailnag/plugins/Testing.py and ran it, which did bring up the "You got new mail" message.   #!/usr/bin/env python2 import os os.system('zenity --info --text="You got new mail"')


Give away paid app on App Store for free

I will soon release my macOS and iOS apps on the respective App Store, but before I do this I need to make sure about a few things.  Will App Store allow me to upload a paid app but still give me the right to give away free licences to people I choose? I have a few special customers who paid for it before it was on App Store, and I would like to allow them to still download from the App Store without having to pay twice. If it's possible, could you show a brief instruction on how it could be done?


How to avoid the pop up message while downloading an application (.exe) using selenium

I am trying to download an application and check if it's downloaded into my local system or not. But when I click the download link I have a popup with Save or Cancel options, which is stopping me from downloading the file. I googled and found some solutions and tried to change the profile of Firefox by adding the below code, but it is not working.  firefoxProfile.setPreference("browser.download.folderList", 2); firefoxProfile.setPreference("browser.download.alertOnEXEOpen", false); firefoxProfile.setPreference("browser.helperApps.neverAsksaveToDisk", "application/x-msexcel,application/excel,application/x-excel,application/excel,application/x-excel,application/excel,application/vnd.ms-excel,application/x-excel,application/x-msexcel"); firefoxProfile.setPreference("browser.download.manager.showWhenStarting", false); firefoxProfile.setPreference("browser.download.manager.focusWhenStarting", false); firefoxProfile.setPreference("browser.helperApps.alwaysAsk.force", false); firefoxProfile.setPreference("browser.download.manager.alertOnEXEOpen", false); firefoxProfile.setPreference("browser.download.manager.closeWhenDone", false); firefoxProfile.setPreference("browser.download.manager.showAlertOnComplete", false); firefoxProfile.setPreference("browser.download.manager.useWindow", false); firefoxProfile.setPreference("browser.download.manager.showWhenStarting", false); firefoxProfile.setPreference("services.sync.prefs.sync.browser.download.manager.showWhenStarting", false);   This is the code I added for setting up Firefox preferences, but I still get the popup.


Null pointer exception in populating a treemap

The following code gives me an nullpointer exception when trying to populate the treemap. More specifically at the line OpponentModel.put(OfferedUtil, OfferedBid); I can't seem to get this working whatever i try.  public TreeMap<Double ,Bid>  updateOpponentModel(Double OfferedUtil, Bid OfferedBid) {     if (OpponentModel==null){         OpponentModel.put(OfferedUtil, OfferedBid);     }     else if ( OpponentModel.size()< 5 ||   OpponentModel.firstEntry().getKey()<OfferedUtil) {         if ( OpponentModel.size() == 5){             OpponentModel.remove(OpponentModel.firstEntry());         }         OpponentModel.put(OfferedUtil, OfferedBid);         //System.out.println("Updated Opponent Model utility:"  +OpponentModel.firstEntry().getKey());         //System.out.println("With utility:"  + OfferedUtil);     }     //System.out.println("check size: "+ OpponentModel.size());     return OpponentModel; }


I am using platform event and subscribing them in a lightning component. When i use my component as standalone lightning app or use it on lightning record page, the components subscribe well to the event.  // Client-side function that invokes the subscribe method on the empApi component. subscribe: function (component, event, helper) {     // Get the empApi component.     console.log('calling to subscribe');     debugger;     var empApi = component.find('empApi');     // Get the channel from the attribute.     var channel = component.get('v.channel');     // Subscription option to get only new events.     var replayId = -1;     // Callback function to be passed in the subscribe call.     // After an event is received, this callback prints the event     // payload to the console. A helper method displays the message     // in the console app.     var subscribeCallback = function (message) {         console.log('Event Received : ' + JSON.stringify(message));         helper.onReceiveNotification(component, message);     };     // Subscribe to the channel and save the returned subscription object.     empApi.subscribe(channel, replayId, subscribeCallback).then($A.getCallback(function (newSubscription) {         console.log('Subscribed to channel ' + channel);         component.set('v.subscription', newSubscription);     }));      /*.catch(         function(error) {             console.error('cant subscribe to event ', JSON.stringify(error));         }     );*/ },   In the subscribe method - there is a console log - Subscribed to channel.   empApi.subscribe(channel, replayId, subscribeCallback).then($A.getCallback(function (newSubscription) {     console.log('Subscribed to channel ' + channel);     component.set('v.subscription', newSubscription); }));   It works fine for above mentioned scenarios and gets called well from Init.  If i put the component on the community page, the component stops subscribing and 'Subscribed to channel' does not show.


I have an 8GB USB drive which is completely empty and I would like to copy  to it.   Is there a way I can copy to the USB so I can play it on another PC without Steam being required on the PC?


Two women rescued a child who was kidnapped by his neighbour.   or     Two women rescued a child who had been kidnapped by his neighbour.   Which one is correct and why?


drupal_get_title() has been removed from Drupal 8. How I can get the page title in Drupal 8?


How do you turn off comments on a SharePoint list?

I do not want users to be able to add comments to each row of my SharePoint lists. How do I turn this feature off?


Why Xcode is downloading from the beginning ,if downloading gets failed?

I have an Question that just want to clarify that Xcode is downloading from the beginning if the downloading gets failed. I am trying to download Xcode 10.1. It gets downloaded 75% if their must be an network issue,downloading gets failed and it start downloading from the beginning ,Here my question is why its doesn't start where it leaves.


How can I figure out what questions will be on topic for a particular Stack Exchange site?

Is there a list somewhere, that explains which questions are appropriate in each of the Stack Exchange sites?  Frequently, I'd ask a question on /// et al., based on the site's similar questions, only to be notified by the site moderators that my question is inappropriate for their site.  How can I learn what can be asked about so that I can ask questions that won't be closed as off-topic?


Is the dihedral group of order 8 the group of units of some ring?

Let $R$ be a ring. An element $r \in R$ is a unit of $R$ if there is some $s \in R$ such that $rs=sr=1$. Denote the set of units of $R$ by $R^{\times}$. It is easy to verify that $R^{\times}$ is a group under the multiplicative operation of $R$.  I am trying to find a ring $R$ such that $R^{\times} \cong D_4$. Recall that $D_4$ is the dihedral group of order 8 which has the following presentation: $\langle a,b ~|~ a^4 = 1, b^2 = 1, bab=a^3 \rangle$.  More generally, is every finite group the group of units of some ring?


For what value of $n \in \Bbb N$ the function $f(x)=x^n$ is uniformly continuous in all of the set $\Bbb R$_  I've been trying to work on this problem but I don't really know what to do.  Can you help me understand this problem?


What happens if I call the 3 ball in one corner and the 8 ball in another?

My last ball on the table is the 3.    I call the 3 ball in one corner and the 8 ball in the other corner. I make contact with the 3 ball first, then the 8 ball. Does it matter if the 3 ball goes in or not? Assuming the 8 ball goes in.    Was this a legal call to begin with?


I have a JavaScript array like below:  [     {type: 'text', name: 'title', id: 'title', placeholder: 'Type here'},     {type: 'textarea', name: 'description', id: 'description', placeholder: 'Type here'} ]   Now I want to inset {type: 'text', name: 'age', id: 'age', placeholder: 'Type here'} after first object. So my final result set will be looks like:  [     {type: 'text', name: 'title', id: 'title', placeholder: 'Type here'},     {type: 'text', name: 'age', id: 'age', placeholder: 'Type here'}     {type: 'textarea', name: 'description', id: 'description', placeholder: 'Type here'} ]   I want in plain JavaScript or jQuery!


Evaluate $\lim\limits_{\alpha \to \infty} e^{-\frac{t}{\sqrt{\alpha}}}(1-\frac{t}{\sqrt{\alpha}})^{-\alpha}$

How does one show  $$\lim_{\alpha \to \infty} e^{-t\sqrt{\alpha}}\left(1-\frac{t}{\sqrt{\alpha}}\right)^{-\alpha} = e^{t^2 / 2}?$$  Not homework, this is from this  as $\alpha \to \infty$. It suggests using numerical techniques to find the limit of the above, but I would like to know if there is a good way to solve this manually. I tried L'Hopital's rule but got $e^t$, which is obviously incorrect.


Can't log in using Firefox in Stack Overflow

Here's what is happening; everytime I go to Stack Overflow (stackoverflow.com, NOT meta) with Firefox, it gives me the "Welcome back" tab that pops up from the top. Whenever I click in the "click here to refresh the page" link, all it does is refresh the page without logging me back in.  Even if I try to log in using the "log in" button at the top, all it does is pop up the tab that says "Welcome name here, you're being redirected." The problem is I'm not being logged in, not to mention that it keeps refreshing the page over and over again without giving me a choice to log in with Facebook.  For some reason, I was capable of logging in to Meta Stack Overflow using Firefox. I am still unable to log in to Stack Overflow. Any ideas?


A command with a variable number of arguments: comma versus and

I have the following command: \newcommand{triangles}[2]{triangles $\triangle #1$ and $\triangle #2}, such that \triangles{ABC}{DEF} produces triangles $\triangle ABC$ and $\triangle DEF$. I would like to expand that command such that it can take any number of arguments and such that \triangles{ABC}{DEF}{GHI}{JKL} produces triangles $\triangle ABC$, $\triangle DEF$, $\triangle GHI$ and $\triangle DEF$. I have seen a solution somewhere for a shoppinglist that makes use of \makeatletter and some TeX command, but this is more difficult, I think, because before you add the current argument, you need to know whether it is the last argument (if not: put a comma, if yes: put "and").


What's the difference between burning a book and throwing it into a black hole

There is a big concern about loosing information inside a black hole. As far as I understand, the black hole is characterized classically by its mass, angular momentum and charge. Semi-classically, thermal radiation is added. Lot's of effort is paid to somehow restore the amount of information that crossed the horizon of a black hole, e.g. holographically on the surface of the event horizon. Why is it not allowed to simply loose the information? Is it related to the reversibility of fundamental laws of nature? If I burn the book, all the information that was stored in the special arrangement of paper and ink atoms are lost as well. Of course, the atoms still exist, but the content of the book that they were storing is lost. What is the difference in the quality of information loss between the burning and the crossing of the event horizon? Could the black hole just simply be a cosmic fire that burns everything irreversibly into thermal radiation?


Meaning of 'such' in "Such was her astonishment"

Here's the context       "Her heart leaping into her throat, she tiptoed into the salon. Such was her astonishment at seeing Mike chatting with her boss that she leaned against the wall, incapable of making another move."   Is this a phrase or what? Could it be used in other forms as well?


With the cyclic group $C_n $, why can't we say $C_4$ is isomorphic to $C_2 \times C_2$?  Is it because 2 and 2 are not coprime?  Are there any other types i should watch out for?


"A  is a platform for conducting rigorous, transparent, and replicable testing of scientific theories, computational tools, and new technologies" (Wikipedia).  While Wikipedia seems to prefer "testbed",  and   prefer "test bed". I have seen "testbed" predominantly in the scientific literature I have been reading. Should I mirror the literature or add the additional space?  I have read this great  which focuses mostly on hyphenation usage. Rather I am looking for guidelines for open versus closed forms. Most of the answers address this indirectly, giving descriptive rather than prescriptive answers. Many answers also allude to the differing standards of hyphenations in different contexts.


How to solve this integral? This one is the hardest!

integrate from 0 to 1 $$\int \frac{x^7-1}{\log x} \, \mathrm{d}x$$![It's from MIT integration bee][1]  I try to solve this by substitution but nothing works out. Solving this problem from 10 days .I have no idea how they have a answer $\log(8)$.


Radius of Convergence of a given Power series

I came across this question.  Let $d(n)$ denote the number of divisors of $n$. Let $$\nu(z) = \sum\limits_{n=1}^{\infty} d(n) z^{n}$$ Whats the radius of convergence of this power series. We also have to show that $$\nu(z) = \sum\limits_{n=1}^{\infty} \frac{z^{n}}{1-z^{n}}$$  Regarding the divisor function, we have Dirichlet's formula in hand. But will that help!