How is this user able to review posts so long after they were completed originally?

This is a revisit of  that seems to have grown stale without any solid answer. Just recently I was baffled by 's ability to :  In my experience, certain review queues seem to be more inclined to "single-user reviews" (like First Posts and/or Late Answers), while others are more geared to "multi-user reviews" (like Close Votes and/or Suggested Edits). This does not seem to be the case here. The "requirement" for such late, duplicate reviews are questionable and               (         ). Even being able to  (I highly doubt this was an instance of keeping the review window open for more than an hour and only reviewing it post mortem - first post reviews are dealt with far more quickly than most other review queues):   While these examples do not speak to the , it sure seems biased. Something is amiss... Over at  we have a far smaller community, so these situations are far more noticeable.  Edit: The following are all candidates for the above discussion:


This might sounds stupid, but I really don't know can I show Irrational numbers in proves? And if so, how to show it?  For example, when I want to show Rational numbers, I do this:  $\frac{m}{n} $ , $m, n $ are integer $,$ $n\ne0$  Can I do something like that with Irrational numbers?


Prove the following relation in vector space

Let $(V,+, \cdot)$ be a $\mathbb{K}$ -vector space. Prove the following relations.  $\mathrm{o} \cdot x=\mathrm{o},$ for all $x \in V$ $\lambda \cdot \mathrm{o}=\mathrm{o},$ for all $\lambda \in \mathbb{K}$. $(-1) \cdot x=-x$ for all $x \in V$.   Here is my idea, if it has some problems or you have to add for me please kindly share an idea for me. Since $(V,+,\cdot)$ be a $\mathbb{K}$ -vector space.  $\exists \mathrm{o}=0 \in\mathbb{K}$ for all $x\in V$ $$\mathrm{o}x=0x=0=\mathrm{o}$$ $\exists \lambda\in\mathbb{K}, \lambda\cdot\mathrm{o}=\lambda \cdot 0=0=\mathrm{o}$ Since $-x\in V$ such that $(-1)\cdot x=1\cdot(-x)$   Please kindly share or recommend me. Thank in advance!


How do I kill all a user's processes using their UID

I want to kill all running processes of a particular user from either a shell script or native code on a Linux system.  Do I have to read the /proc directory and look for these?  Any ideas? Is there a dynamic mapping of the pids under UIDs in Linux? Isn't this in the proc?  If not, then where is this list maintained? Should I read from it? Also where is the static list of all UIDs in the system so I can validate this this user exists and then proceed to kill all processes running under it?


I have a class file which when i compile shows me Null pointer exception in a particular line all the time. I handled null check as below.  108    doc = Jsoup.parse(html, brandUrl);  109    Element div = doc.getElementById("eventTTL"); 110    String attr = div.attr("eventTTL"); 111    Date closingDate = new Date(Long.parseLong(attr)); 112    Elements mainForm = doc.select("div#main-form"); 113    Elements mainDivs = mainForm.select("DIV");   java.lang.NullPointerException     at com.textT.at.Chickyur.main(Chickyur.java:110)  if(div != null) String attr = div.attr("eventTTL");    Also tried   if(div.attr("eventTTL") != null)  String attr = div.attr("eventTTL");    Still i keep getting the exceptions. What is wrong? any thoughts?


How can we substitute $r \cos \alpha$ and $r \sin \alpha$ for $a$ and $b$?   How, on successive differentiation, is there another $r$ multiplied?


Me, being new to Skyrim, accidentally punched someone and received a bounty of 40. Then, I said "I would rather die than go to jail" to a guard, not knowing this would make everyone hate me and attack me. How can I fix this without resetting my game or anything like that?


Here is my script (to find the files that contain a specified pattern):  find . -type f \     -exec awk -v vawk="$1" '/'"$vawk"'/ {c++} c>0 { print ARGV[1]; exit 0 } END { if (! c) {exit 1}}' \{\} \;   I would like to use my script with an argument §:  MyScript.sh pattern   My problem is that I don't manage to put the $1 variable in awk.  When I try to debug my script  bash -x MyScript.sh pattern   Here is the output :  + find . -type f -exec awk -v vawk=pattern '// {c++} c>0 {print ARGV[1] ; exit 0 } END { if (! c) {exit 1}}' '{}' ';'   The $vawk variable seems to be empty.  Any idea?


If I was to live and avoid terrible deficits, I would have to have urgent surgery.   Is this grammatically correct? Shouldn't it be "If I were"? Most importantly, what is the grammar rule governing this concept?


Number of sigma algebras for set with 4 elements

I am supposed to watch out for sigma algebras that belong to the set $X=\{1,2,3,4\}$. I found 15(now with the new set even more) of them. I was wondering whether there is some nice proof how to see that there are no more of them? The problem is, that I would try to prove this by looking at a lot of different cases, how a new sigma-algebra would have to look like and prove then that it already is the whole set. Does anybody here have a better idea?  only the set and the empty one// the set of all subsets// 4 sets, where you take the set, the empty one and one element with its complement.// 3 sets with the empty one, the set itself and a set containing two elements and its complement.// EDIT: I have even found 6 of another type that are possible, just like: $\Sigma = \{\{1\},\{2\},\{1,2\},\{3,4\},\{1,3,4\},\{2,3,4\},\emptyset,X\}$  Does anybody have an idea?


Creating coverage file (vector) from raster data and indexing it to original files?

I have a large number of LiDAR files (in .asc format) that I'm wanting to catalogue so it is easier for people to find the files they want.  How can I take LiDAR files I have, and create a .shp file (ideally polygons) of the areas covered.    My end goal is to have a .shp file people can open on top of a map, check whether or not their location has been covered by LiDAR and then identify the file name that they're after.


Deactivating Facebook but keeping my SO account

The two are linked, i.e. I sign into SO using my Facebook credentials. If I were to deactive my Facebook account, what options do I have available to me for still signing in to my original SO account as opposed to creating a new one?


Ubuntu 18.04 "unable to connect to scanner"

I have an HP MFP M225dn multipurpose printer-scanner. In my new install of 18.04, printing works fine, simple scan recognizes the scanner but won't scan ("unable to connect to scanner"). Was working fine with 16.04 and the HP print manager (HPLIP) software. Anyone else seeing this? Should I install the HPLIP drivers etc. from HP? They do not list 18.04 compatibility. Cheers  p.s. Sane detects the scanner:  xxxxxx@daniel-Z370N:~$ sudo sane-find-scanner    # sane-find-scanner will now attempt to detect your scanner. If the   # result is different from what you expected, first make sure your   # scanner is powered up and properly connected to your computer.    # No SCSI scanners found. If you expected something different, make sure that   # you have loaded a kernel SCSI driver for your SCSI adapter.  found USB scanner (vendor=0x03f0 [Hewlett-Packard], product=0x2d2a [HP LaserJet Pro MFP M225dn]) at libusb:001:014   # Your USB scanner was (probably) detected. It may or may not be supported by   # SANE. Try scanimage -L and read the backend's manpage.    # Not checking for parallel port scanners.    # Most Scanners connected to the parallel port or other proprietary ports   # can't be detected by this program.  xxxxx@daniel-Z370N:~$ sudo scanimage -L  device `hpaio:/usb/HP_LaserJet_Pro_MFP_M225dn?serial=CNB9HBWD3M' is a Hewlett-Packard HP_LaserJet_Pro_MFP_M225dn all-in-one  xxxxx@daniel-Z370N:~$


Product of all prime numbers on the interval [m+1, 2m] is $\le \left(\begin{matrix} 2m \\m\end{matrix}\right)$

Show that for every m the product of all prime numbers on the interval $[m+1, 2m]$ is  $ \le \left(\begin{matrix} 2m \\m\end{matrix}\right)$   I don't know how to do this, maybe somehow show that all the prime numbers on that interval are divisors of the combination number or something like that...


Does Anyone Know How to Use Wine Securely?

I switched over to Ubuntu and wanted to play some of my older Steam games such as Star Wars Battlefront 2 (2005) using Wine. I know Wine can cause security issues if not installed and used properly which will bother me since I take security really seriously. Does anyone know how I could do all of this properly? Thanks!


#include <iostream>  using namespace std;  int main() {   float a = 6.2;   if (a < 6.2) {     cout << "Yes\n";   }   return 0; }  This code prints yes, Can someone explain why?


How many Valyrian steel swords are there in all seven kingdoms?

In the series Game of Thrones, how many Valyrian steel swords are there in all seven kingdoms and who holds them? It can be a reference to the sword or a scene showing the sword.


Do stone quarries respawn in Hearthfire?

In Skyrim: Hearthfire, the stone quarries only give the player a total of 4,000 quarried stone from one place at a time before it says it's depleted. Will the quarries replenish their stone after an in-game month passes like the mines do, or is there a finite amount of quarried stone?


$\sum_\limits{n=0}^{\infty} a_n$ converges $\implies \sum_\limits{n=0}^{\infty} a_n^2$ converges

Let $(a_n)$ be a sequence of positive terms and suppose that $\sum_\limits{n=0}^{\infty} a_n$ converges. Show that $\sum_\limits{n=0}^{\infty} a_n^2$ converges.   This is in the section on the Comparison Test so that must be what I'm supposed to use.  But I don't see how.  $(a_n)^2$ might be smaller or larger than $a_n$ depending on $a_n$.  And I can't use the Comparison Test with some other series because there's no info here about how fast $\sum a_n$ converges.  Hmm.  Any hints?


How do I force iPhoto to download new photos in my Photo Stream?

I'm listing some items for sale online, and have taken a bunch of pictures with my iPhone.  About half-way through the process, iPhoto '11 stopped downloading new photos into its local Photo Stream.  I've quit iPhoto and re-opened it.  I've gone into the Photos app on my iPhone and confirmed all the pictures are there.   Is this normal behavior? Is there any way to tell iPhoto to download my pictures?


How can classical electrodynamics be a complete theory of electromagnetism when it's based only on special relativity?

When charges are not accelerating Lorenz transformations suffice but dealing with accelerations goes formally beyond the scope of special revativity


Cardinality of the quotient ring $\mathbb{Z}[x]/(x^2-3,2x+4)$

This problem is from a practice exam I was working on.     What is the cardinality of the quotient $\mathbb{Z}[x]/(x^2-3,2x+4)$ ?   Thoughts. If I find a ring that is easier to handle then this then I can go from there. So I think this is isomorphic to $\mathbb{Z}_2[x]/(x^2-3,x+2)$. And then I am stuck.  Am I correct so far? What should I be looking to do from here?  Thanks for your time and your answers.


Why is $x + x = 2x$, but $X + X \neq 2X$?

At this AP central page , the author, Peter Flanagan-Hyde draws a distinction between algebraic and random variables.   In part he says     $x + x = 2x$, but  $X + X \neq 2X$   -- in fact it's the subtitle of the article.  What is the basic difference between an algebraic variable and a Random Variable?


Window title in bottom of Activities overview is not visible when opening multiple windows

Ubuntu Dock on Left of screen with no window title:   Ubuntu Dock on Bottom of screen with window title:   I would like some help in fixing this behavior: with the Ubuntu dock on the left or right of the screen the title of the windows on the bottom of screen is not visible but if I have the dock on the bottom of the screen the window title is visible. I tried searching online for the issue but I didn't know exactly how to search for this issue.


How is $\cos (\pi/2+h)$ equal to $-\sin(h)$?

I am not able to grasp the logic behind how $\cos(\frac \pi2+h) = -\sin(h)$. I was able to find an explanation on Reddit but it is not clear. Can anybody elaborate in a better way?  Here is the link to the explanation -


How many rolls do I need to determine if my dice are fair?

Roughly how many times do I need to roll a 6-sided die to feel confident that it's giving "fair" results? What about a 10-sided or 20-sided die?  Note that I will be actually manually rolling physical dice, this isn't just a textbook exercise. I'd like to minimize how long it takes me to perform this experiment with each die :)   I know this depends on my expected "confidence level" (95%? 99%?) If I choose a 95% confidence, for example, does that imply that 1 out of 20 fair dice will fail this test? Or that a single fair dice would fail the test 1 out of 20 times? If so, that sounds fairly high.   Are there standard techniques for doing this kind of a test?  Edit: It is beyond the scope of the math-focused question I've asked here, but I've explained more about the overall testing scenario over on the stats site here:


Sorry for the wrong way of title used before.   All sub domains of stackexchange.com have a restriction of "minimum reputations required" for Chat Comment and Image uploading. When members have non-sufficient reputation,    In case of image, if my question does need an image to upload to ask the question specific to topic, and if it is happened to be my first question, or my nth question with below required reputation, I cannot get specific or perfect answers. Images especially of errors, warnings or snapshots of how does the application currently look like(if it is not be explained in words) are prominent among who face those errors before. So by uploading the image they can answer the specific answer. I find no logic in relating reputations with uploading images to ask an efficient question. It will make the new member of this community helpless. In case of comment, some questions or answers need to be clarified slightly different than the questions or answers provided. In this case members with below than required reputations cannot ask a new question just to get small missing information from another answers. In most of the cases the questions asked slightly different than the existing questions will also be considered as duplicate by the forum moderators and members with high reputation. This will lead the member to loose the small reputation that he had before. By opening comment capability to all members irrespective of reputation will enable answerers to update the answer with more information and prevent duplication of questions. When it comes to chat, some domains such as stack overflow restricted a reputation of 50!!. When there is no facility to send personal messages to the members of community, to contact the member for getting additional information about the comment or answer they have posted or to make them know that someone is trying to reach them, is only possible by leaving a msg through chat. for eg: In  post the member GrIsHu has commented to check out the answer provided by him. But there is neither answer posted not link have provided. Now I cannot comment(because of non-sufficient reputation), and I cannot leave a chat msg too(and its a dream to get 50 reputation immediately so that I can enter chat) finally I have no way to ask him the link of the answer he has posted. Even using chat we can get instant help without asking new question.   When members with very high reputation(>50K) use comment to offend each other(In many posts posted on sub domains of stack exchange that I don't like to disclose), new members with <50 reputation who are in hurry or in need of immediate help can't get simple clarifications on answers with high up votes or the required answer in time.  I personally not getting the logic behind restricting newbies to upload an image, use comment for either for clarification or suggestion and restriction on chat to get instant help or use as a means of contacting a particular member.  What is the genuine reason behind these restrictions?


How does a frame of reference work in relativity?

I am struggling to understand what frame of reference means in relativity. Imagine the twin scenario. Twin A is at rest, while twin B travels somewhere and back at near the speed of light. If one takes as a frame of reference the one where twin A is at rest, then time goes slowly for Twin B, thus making it so that when B returns, A is older.  Now I get really confused, if I take twin B's rest frame as the frame of reference, then he was stationary all the time, and A was moving at close to the speed of light, thus B will be older than A. What am I getting wrong here?


Freeze Soup very quickly Without Destroying the Content In Fridge?

I am trying to finish soups faster. I have very heavy iron kettle and it takes years to become cold. I use a water container with ice with it but the hot water still takes a lot time to become cold. I have already put ice cubes into the soup and some cold water but it is still hot! How can I freeze my soup fast without destroying the content of my fridge or freezer? It is now almost two hours waiting it to become colder but with this heavy iron kettle and a lot of hot water, it is taking years.  Could I put the soup into small plastic bags and the plastic bags into the cold water and then the cold plastic bags into the fridge (I have no special plastic bags, perhaps they will break)? I need to somehow make the soup smaller to increase the area, to get it cold faster. By increasing the area, I am sure I can get it cold faster. Ideas to do that?


Meta participation privilege should require 5 rep or... something else

So, you've got a new user.  They ask a really poor question (P.SE ) poorly written, off topic, or any other number of other things.  There is no way to redeem such a question on the site, it falls into the embarrassingly bad category and got deleted. There is only so much down voting and trying to help in the comments can be done (comments are a poor way to educate someone about the fundamentals of asking a question on Stack Exchange... but thats another matter).  in this particular anecdote, the person came to MSE and asked, and was given the advice to ask on the .  However, the question was asked on  and then .  One difficulty in this entire process is that it means that without that sympathy up vote on the misasked question on the main site, the OP is completely unable to ask on the per site meta.  Help > Privileges >      Participate In Meta   Privilege Type: Communication Privilege   Awarded At: 5 Reputation   And so, the person who asks a really poor question can't get to meta to ask why its really poor without a sympathy up vote.  And so, without excess bouncing of a person through the meta bureaucracy, how can we actually get someone to be able to ask on meta with only 1 rep?  Ok... so the reasoning behind this is:     Because we allow anonymous participation, we require a small bit of parent site reputation to prevent spam, and ensure that meta is for active, engaged members of the community.   Unfortunately, I don't know how often other sites get meta spam... or how prevalent it was in days before this permission was put in place.  Proposal:   Is the requirement of 5 rep or a registered user sufficient to keep away the meta spam while allowing people who genuinely need help the ability to post on meta (without coming over to MSE where the question is off topic)?


Using Tikzpicture, I have the following automata:  \documentclass{article} \usepackage{tikz} \begin{document} \usetikzlibrary{positioning,arrows,automata} \begin{center} \begin{tikzpicture}[>=stealth',shorten >=1pt,node distance=2cm,on grid,initial/.style={}] \node[state,initial]  (a0)                   {}; \node[state]          (a1)  [right =of a0]   {}; \node[state]          (a2)  [right =of a1]   {}; \node[state]          (a3)  [above =of a2]   {}; \node[state]          (a4)  [below =of a0]   {}; \node[state]          (a6)  [right =of a4]   {}; \node[state]          (a7)  [right =of a2]   {};    \node[state]          (a8)  [right =of a7]   {}; \node[state]          (a9)  [right =of a8]   {};  \node[state]          (a5)  [above =of a9]   {}; \node[state]          (b0)  [right =of a6]   {};  \node[state]          (b1)  [right =of b0]   {}; \node[state]          (b2)  [right =of b1]   {};  \node[state]          (b3)  [right =of b2]   {}; \node[state]          (b4)  [right =of a9]   {};                                 \tikzset{every node/.style={fill=white}} \tikzset{mystyle/.style={->,double=red}}   \path (a4)     edge [mystyle]       node   {$0$} (a6)       (a2)     edge [mystyle]       node   {$0$} (a7)       (b0)     edge [mystyle]       node   {$0$} (b1); \tikzset{mystyle/.style={->,double=blue}}   \path (a3)     edge [mystyle]       node   {$1$} (a5)       (a8)     edge [mystyle]       node   {$1$} (a9)       (b2)     edge [mystyle]       node   {$1$} (b3);               \tikzset{mystyle/.style={->,double=yellow}}   \path (a0)     edge [mystyle]       node   {$\varepsilon$} (a1)       (a1)     edge [mystyle]       node   {$\varepsilon$} (a2)       (a1)     edge [mystyle]       node   {$\varepsilon$} (a3)       (a1)     edge [mystyle]       node   {$\varepsilon$} (a4)       (a6)     edge [mystyle]       node   {$\varepsilon$} (b0)       (a7)     edge [mystyle]       node   {$\varepsilon$} (a8)       (b1)     edge [mystyle]       node   {$\varepsilon$} (b2)       (a9)     edge [mystyle]       node   {$\varepsilon$} (b4)       (a5)     edge [mystyle]       node   {$\varepsilon$} (b4)       (b3)     edge [mystyle]       node   {$\varepsilon$} (b4); \end{tikzpicture} \end{center} \end{document}     Now, I want to add a yellow epsilon arrow from the node on the far left (a0) to the node on the far right (b4).  However, I have absolutely no idea how to do this without the arrow cutting through the rest of the automata.   Can I get some help here?


What is the difference between correlation and mean absolute percentage error?

So here is my question, I have to columns of data. One of them is a black box model's output, and the other one is my actual numbers. The correlation between these two columns is 99%, but the MAPE is around 5%. How do I interpret this? I know R2 means the model output is able to predict 100% of the variability in my actual numbers, but how does the MAPE of 5% come into play? Do I just say the model's error is 5%? How do I use correlation to make any points about the model's output?


Can I increase an ability score above 30?

Can I increase an ability score over 30 with an item such as a Manual of Bodily Health?     [After reading] this book... your Constitution score increases by 2, as does your maximum for that score.


Given a board of size $1 \times n$,in how many this board can be colored with the colors white,yellow,blue assuming the number of blue cells is even

Given a board of size $1 \times n$,in how many this board can be colored with the colors white,yellow and blue assuming the number of blue cells is an even number.  My try: Given a board of size $1 \times n$,then there are two possibilities for the color of the first cell:  If the first cell is blue then the it's needed to find another cell to color it with the blue color ,this can be done in $n-1$ ways and for each one of these choices there are $b_{n-2}$ ways to color the remaining $1 \times (n-2)$ board with the colors yellow,white and blue assuming the number of blue cells is an even number.  If the first cell is yellow or white then the remaining $1 \times (n-1)$ board can be colored in $b_{n-1}$ ways assuming the restriction on the number of blue cells is satisfied.   Gathering these cases follows: $$b_n=(n-1)b_{n-2}+2b_{n-1}$$ With $b_0=1$ and $b_1=2$ as initial conditions. Calling $G(x)=\sum_{k\ge 0}^{} b_k x^k$,omitting some elementary calculations follows: \begin{align*} G(x)&=\frac{-1}{\left(n+1\right)^{2}x^{2}+2x-1}\\ &=\frac{-1}{\left(n+1\right)^{2}}\frac{1}{(x-a)(x-b)}\\ &=\frac{1}{\left(n+1\right)^{2}(a-b)}\left(\frac{1}{a-x}-\frac{1}{b-x}\right)\\ &=\frac{1}{\left(n+1\right)^{2}(a-b)}\left(\frac{1}{a}\frac{1}{1-\frac{x}{a}}-\frac{1}{b}\frac{1}{1-\frac{x}{b}}\right)\\ & \end{align*} From which we conclude: \begin{align*} b_n=\left[x^{n}\right]G\left(x\right) &=\frac{1}{\left(n+1\right)^{2}(a-b)}\left(\left(\frac{1}{a}\right)^{n+1}-\left(\frac{1}{b}\right)^{n+1}\right)\\ \end{align*} Where $$a=\frac{-1+\sqrt{n+2}}{n+1},b=\frac{-1-\sqrt{n+2}}{n+1}$$ But the closed form does not coincide with the recurrence that I've found.(I only want the question to be solved using recurrence relations.)


I'm opening a page in an iframe and wish to hide some of the page elements. I've tried the following with a single item: <script type="text/javascript"> window.onload = function() {   document.getElementByClassName('banner-covid19').style.display = 'none'; }; $(document).ready(function() {     $("#banner-covid19").hide(); }); </script>  Nothing seems to happen when I update the iframe. Is there something I'm missing? Ideally, I'd like to hide multiple items with different class names.


Punctuation of compound predicate where the first item ends in a list?

I apologize in advance for any and all wrong use of terminology.  Consider a sentence of the form      The project was created to practice X and learn Y.   I believe the "practice X and learn Y" is a compound predicate and so there should be no comma before the "and". However, I get confused if X is a list. If I simply replace the X by "V, W, and X", I get      The project was created to practice V, W, and X and learn Y.   Is this correct? It looks strange to me, and I'm not so sure since the "X and learn Y" could be read as a single item? I was going to write a similar sentence, and I wrote it as     The project was created to practice V, W, and X, as well as to learn Y.   However, if the "as well as" is just a placeholder for "and", then isn't the comma before "as well as" wrong, since it "splits a compound predicate"?  Any help is appreciated. Thank you for your time and have a great day.


i have a samsung galaxy 3 and I dropped it and it cracked which has been fine. Just lately the top left corner has been turning blue and is spreading to the right side and lower what is it and what should i do?


Can anyone help me prove the following equivalent found in Peskin & Schroeder on page 27.  $$ \frac{1}{4\pi^2}  \int_{m}^{+\infty} dE \sqrt{E^2-m^2} e^{-iEt} \sim_{t \to \infty} e^{-imt}$$    The integral is divergent, I understand that it has to be understood as distribution but still I'm not sure how to prove it.  I'm looking for a rigorous proof possibly using distribution theory. I am not convinced by the simple change of variable argument.  Edit: This question is indeed a duplicate, however, the answer provided is not as rigorous as I would have liked (using distribution theory) and the given answer I believe is not correct. , the correct equivalent is  $\sim \frac{e^{-imt}}{t \sqrt{t}}$ and not $\sim e^{-imt}$ as claimed in Peskin and Schroeder or $\sim \frac{e^{-imt}}{t}$ as claimed by the answer in the duplicate.


When $abc=1$ find the minimum of $a^2+b^2+c^2$.  My attempt:I put $\frac{1}{bc}$ for $a$ and then I used AM-GM inequality.  $(\frac{1}{bc})^2+b^2+c^2\ge 3$  But finally we should get the answer $a+b+c$.  Where am I wrong?


What's the good way to find outliers in the continuous physical process measurements time-series? (picture attached)

What's the best way to find outliers in the time-series like the one attached? Just using the knowledge that it is a measurement of a continuous physical process. The data is quite short (200-500 samples) and it is not really periodic.  Thanks


Why is there no electric field in the hollow space of the dees of a cyclotron though it is open at one face? Is electrostatic shielding applicable for space(hollow space) inside open conductors(like dees) also?


How can I install XFCE and completely remove Unity

I use Ubuntu 12.04 (I have not upgraded to 14.04 for performance reasons) but I don't like Unity. How can I install XFCE as my default graphic system, and completely remove Unity?


Show a function in $C$ is constant function if modulus of $f$ less that a given function

I tried to use Liouville theorem to show that function is a constant function first, but I found it useless. Then I found that modulus of 1/$f$(z) is less than a bounded function, but here also lead to a problem that I cannot make sure the 1/$f$(z) is holomorphic except origin point. I wonder how to solve this problem.


What happens when many neurons have same weights?

Does it make any sense to have two (or more) neurons in a neural network with the same weights? (intuitively it makes no sense, since all the neurons would behave the same way).   Please consider both the input and hidden layers. What if the weights are equal 0?


A student sent me a question and I am stucked. I'd like to use classical geometry, instead of hard trigonometry if possible (can be trigonometric, but I'd like to not use scientific calculator; the only answer I got I need this), but I am in circles. The pentagon $ABCDE$ is regular. The answer is $48^\circ$ (I've constructed in Geogebra). Thank you in advance!


How do you write a differential operator as a matrix? I'm very confused. Could someone please use examples to help me understand? Preferably with first and second-order linear differentiation.


Windows hybernate vs shutdown + boot up times: Why choose for hibernate?

After reading , a comparison between the different boot times and hibernate times of the different windows OS's of today, I wondered why would I want to hibernate my pc/laptop?  Considering shutdown takes less then 10 seconds and the boot-up takes approx. 10 seconds, this would take a total of 20 seconds and no energy use while off. Whereas hibernate alone takes 23 seconds and the wake-up takes 10 seconds.  Why would I still want to hibernate, considering it takes longer and uses little energy?


I would like to type  how do I do it?  Thanks!


I posted a  and noticed people weren't distinguishing correctly between many of these things: Windows Managers vs Login Managers Vs Display Managers Vs Desktop Environment.  Can someone please clear this up, i.e. tell us the difference between them and how they are related perhaps?  What category does Xorg fall under?  What about Gdm/Kdm/Xdm?  People also talk about X.  What is X?


Assume that a particle is moving with four-velocity $u^\mu$ through a spacetime with metric $g_{\mu\nu}$ ($-+++$ signature).  Let us also assume that there exists a time-like vector field $t^\mu=(1,0,0,0)$.  Is it generally true that the energy $E$ of a particle is given by the following expression:  \begin{eqnarray*} E &=& -mt_\mu u^\mu\\ &=& -mg_{\mu\nu} t^\nu u^\mu\\ &=& -mg_{00}u^0\\ &=& -mg_{00}\frac{dt}{d\tau}? \end{eqnarray*}  In the special case that $t^\mu$ is a Killing vector and $u^\mu$ is tangent to a geodesic then $E$ is a constant of motion of the particle. But the energy of a particle need not remain constant in the general case - is that true?  If $E=-mt_\mu u^\mu$ is indeed the particle mass/energy then does it act as a source of spacetime curvature given that it depends on the $00$-component of the spacetime metric ifself? I suppose that is not a problem.


Does "away" serve as an adverb or an adjective in the following sentence?

The shop is five minutes away.     According to the dictionary, away is an adverb. An adverb modifies a verb. In the above example, what word does away modify? Why is away not an adjective?       The shop is five meters tall.     tall is an adjective in the second example. It modifies five meters (does it?). So why is away an adverb?


Ubuntu 14.04 will not start. I can get is far as the Grub menu but when I select Ubuntu I immediately get a black screen and nothing happens. I can boot normally when I use an older Linux version but unity will not work. Any advice?


What's the parameters atribute in apex:canvasApp used for?

I'm experimenting with the  feature, and embedding it in a Visualforce page, from where I hoped I would have some control over the canvas.  Now, the apex:canvasApp has a property called  and it's description says that they're parameters passed to the canvas app.    When I don't use the parameters attribute the canvas page draws normally, and using firebug I can see the call to the ip address of the canvas app. But for it to be useful to me I need to pass some parameters to the canvas page and when I do use the parameters attribute the canvas simply does not show, and in firebug it does not show any call to the ip of the canvas.  How are these parameters passed or how can one catch them? Using firebug, in the call to the ip of the canvas app, I can't see any of the parameters that I'm trying to pass.  Here's the simple code I'm experimenting with:  <apex:page > <apex:canvasApp applicationName="Test Canvas" height="400px" width="750px" parameters="{vst_cli: '1293'}" /> </apex:page>   Inside the parameters attribute I've tried some different things: "{vst_cli: '1293'}" "{vst_cli: 1293}" "{'vst_cli': '1293'}" All of which had the same effect.  Any help or pointers will be welcome.  Thanks in advance.


My father is trying to move into Ubuntu, and has been playing around for a few months now. This morning he told me that the PC had crashed, and sent me these pictures:    Is this a hardware error or a software error?  If the latter, is a reinstall the only solution or can we expect to be able to save some files?  If the former, is there any way to recover the data? He tells me that there are several files with no backup that he'd like to save, if possible.


What open source software for auto-alignment of photographs?

Do you know any open source tool to automatically align images, similar to the auto align feature in Photoshop?


How can i resolve all external addresses to internal address?

I am currently setting up a Linux server for a WIFI access-point. When ever someone who is connected to the hotspot/access-point? tries to reload a page they get forced onto the one page. Note: this wont have internet access!  ie: user tries accessing www.google.com => it returns 192.168.1.200 or example.domain  I've read that "dnsmasq" can be used to redirect any external addresses to an internal address. but haven't had any luck. Anyone have an example of a config for "dnsmasq"?  I have also read that this can be done through a proxy?


Reapply for ESTA within 90-day period for reentry to the US?

I have entered the US with an ESTA 40 days ago. Now I staying in Mexico for two weeks, after that I am planning to go  back to the US and stay for 1 night only to then take a plane back to Europe. Will I need a new ESTA for my reentry? I will not violate the 90 days mark, everything will happen within that interval. I have heard several opinions now and I am really confused. I hope that you guys can help me. Thanks in advance


How can I insert an indentation before the first paragraph and to leave other paragraphs without it?

I am creating a document in LaTex and my abstract looks like    The code part is:  \section{Введение}  \textbf{Образцы:} 9 клеточных ...  \textbf{Задача:} Выполнить ...  \textbf{Методы исследования:} Анализ ...   As a result I get Задача and Методы исследований with indentation and Образцы without it. How can I insert it when?   A small update What if I need the first paragraph to be indented and others to be not?


what is the difference between a symlink , junction , hard link and so on?

Possible Duplicate:          well just got a litlle confused about all of them. so any explanation?


How to remove Ubuntu and Install Windows

I have Ubuntu 14.04. I installed it on my computer but now would like to remove it to install Windows. I cannot  get the computer to boot from DVD so the windows install will not load. what can I do?


For which integers $n$ there exists integers $0\le a,b,c < n$ such that $n^2=a^2+b^2+c^2$? I made the following observations:  For $n=1$ and $n=0$ those integers doesn't exist.  If $n$ is a power of 2 those integers doesn't exist. Let $n=2^m$ with $m>0$ the smallest power of 2 for which there exists $a,b,c$ such that $\left (2^m\right )^2=4^m=a^2+b^2+c^2$. Since $4^m$ is divisible by 4, $a^2+b^2+c^2$ has to be divisible by 4 too. This is only possible if $a^2\equiv b^2\equiv c^2\equiv 0\pmod 4$, so we can write $a=2a',b=2b',c=2c'$ with $a',b',c'\in \mathbb{N}$. But then we get $\left (2^{m-1}\right )^2=4^{m-1}=a'^2+b'^2+c'^2$, so $m=1$, otherwise $2^m$ wouldn't be the smallest power of two with this property. It is easy to check that $n=2$ doesn't work, so for $n=2^m$ the statement doesn't hold.  I suspect (but can't prove) that for all other values the statement holds. It would be enough to prove that for all odd primes $p$ there exists $a,b,c$ such that $p^2=a^2+b^2+c^2$, since for all other values of $n$ there exist some $p,m$ such that $n=pm$. Then we get $n^2=(pm)^2=(ma)^2+(mb)^2+(mc)^2$.


Does symmetry of a matrix imply orthogonally diagonalizable?

If you have a symmetric matrix, is it orthogonally diagonalizable? Or is the converse only true?


Radius of Convergence of power series of Complex Analysis

I have come across the following few questions on past exams papers.. I know how to solve these type when it is of the form $a_nz^n$ but don't have a clue what to do with these. Any help would be greatly appreciated!  (i) $\displaystyle\sum_{n=0}^\infty \bigg(\dfrac{1}{2n}\bigg)z^{3n}$.  (ii) $\displaystyle\sum_{n=0}^\infty(2^n+i)(z-i)^n$.  (iii) Show that the radius of convergence of $\displaystyle\sum_{n=0}^\infty z^{n!}$ is $1$ and that there are infinitely many $z \in \mathbb{C}$ with $|z|=1$ for which the series diverges.


Why won't Nikon B700 focus close when fully zoomed?

Hello recently I went to best buy and played with a Nikon B500, it was great. I was able to focus on the smallest things, close or far, zoomed all the way in and all the way out. So I went on the internet and found out that the B700 shoots in raw so I got it instead thinking it was better. Only I cant get it to focus on anything close up, weather in macro or not after like 25% zoom it no longer focuses on anything no matter what settings I put it on leaving me to think that I should have gotten the cheaper B500. It may not shoot in raw but at least it would be usable. I am fairly new to photography I had a friend with much more experience come over and try to figure it out. He told me that my camera has a range that it is able to focus on. Only the cheaper B500 focused on things way more zoomed in and with the camera much closer to the object so it doesn't make much since to me. So my question is why wont my camera focus on macro shots (weather in macro or not)?


Natbib+harvard.bst: papers in same year listed in the wrong order

I have a bibliography in which a particular author wrote two papers in the same year. Bibtex is sorting them alphabetically by title, but I want them listed chronologically. (So in the example below 'universal grammar' should precede 'English as a formal language'.) What's the appropriate way to flip the order?  MWE:  \documentclass{article} \usepackage{natbib} \begin{document}  ... formal semantics in the  Montagovian tradition \citep{montague1970aug,montague1970befl,montague1973ptq}.   \bibliographystyle{harvard} \bibliography{test} \end{document}   This generates the text 'formal semantics in the Montagovian tradition (Montague, 1970b,a, 1973)' whereas I actually want '1970a,b,1973'.  test.bib file for MWE:  @incollection{montague1973ptq,   title={The proper treatment of quantification in ordinary {English}},   author={Montague, Richard},   booktitle={Approaches to natural language},   editor={Hintikka, K. Jaakko J. and Moravcsik, Julius M.E. and Suppes, Patrick},   pages={221--242},   year={1973},   publisher={Dordrecht} }  @article{montague1970aug,   title={Universal grammar},   author={Montague, Richard},   journal={Theoria},   volume={36},   number={3},   pages={373--398},   year={1970},   publisher={Blackwell Synergy} }  @incollection{montague1970befl,   title={English as a formal language},   author={Montague, Richard},   booktitle={Linguaggi nella Societa e nella Tecnica},   editor={Visentini, Bruno and others},   publisher={Edizioni di Comunità},   pages={189--224},   year={1970} }


Although rewrite engine is on, I get 404 not found on every page

My wordpress blog has encountered this issue about a week ago. Before that nothing was wrong with it. I got suspicious on web host provider, but they said many times that rewrite engine is on and it works properly.  I ported all source code to my localhost and I have the same issue again. I cannot go to admin section, blogs, etc.    I've read many posts here, but unfortunately gained no success!    What has happened to my blog?    <IfModule mod_rewrite.c>  RewriteEngine On  .  .  . </IfModule>     EDIT 1:    RewriteEngine on     RewriteRule ^/vorood/?$ /wp-login.php [QSA,L]              Order allow,deny         Deny from all                   Order allow,deny         Deny from all                   Order allow,deny         Deny from all                   Order allow,deny         Deny from all                   Order allow,deny         Deny from all       # Rules to disable directory browsing Options -Indexes  <IfModule mod_rewrite.c>     RewriteEngine On      # Rules to protect wp-includes     RewriteRule ^wp-admin/includes/ - [F]     RewriteRule !^wp-includes/ - [S=3]     RewriteCond %{SCRIPT_FILENAME} !^(.*)wp-includes/ms-files.php     RewriteRule ^wp-includes/[^/]+\.php$ - [F]     RewriteRule ^wp-includes/js/tinymce/langs/.+\.php - [F]     RewriteRule ^wp-includes/theme-compat/ - [F]      # Rules to prevent php execution in uploads     RewriteRule ^(.*)/uploads/(.*).php(.?) - [F]      # Rules to block unneeded HTTP methods     RewriteCond %{REQUEST_METHOD} ^(TRACE|DELETE|TRACK) [NC]     RewriteRule ^(.*)$ - [F]      # Rules to block suspicious URIs     RewriteCond %{QUERY_STRING} \.\.\/ [NC,OR]     RewriteCond %{QUERY_STRING} ^.*\.(bash|git|hg|log|svn|swp|cvs) [NC,OR]     RewriteCond %{QUERY_STRING} etc/passwd [NC,OR]     RewriteCond %{QUERY_STRING} boot\.ini [NC,OR]     RewriteCond %{QUERY_STRING} ftp\:  [NC,OR]     RewriteCond %{QUERY_STRING} http\:  [NC,OR]     RewriteCond %{QUERY_STRING} https\:  [NC,OR]     RewriteCond %{QUERY_STRING} (\<|%3C).*script.*(\>|%3E) [NC,OR]     RewriteCond %{QUERY_STRING} mosConfig_[a-zA-Z_]{1,21}(=|%3D) [NC,OR]     RewriteCond %{QUERY_STRING} base64_encode.*\(.*\) [NC,OR]     RewriteCond %{QUERY_STRING} ^.*(\[|\]|\(|\)|<|>|ê|"|;|\?|\*|=$).* [NC,OR]     RewriteCond %{QUERY_STRING} ^.*(&#x22;|&#x27;|&#x3C;|&#x3E;|&#x5C;|&#x7B;|&#x7C;).* [NC,OR]     RewriteCond %{QUERY_STRING} ^.*(%24&x).* [NC,OR]     RewriteCond %{QUERY_STRING} ^.*(127\.0).* [NC,OR]     RewriteCond %{QUERY_STRING} ^.*(globals|encode|localhost|loopback).* [NC,OR]     RewriteCond %{QUERY_STRING} ^.*(request|concat|insert|union|declare).* [NC]     RewriteCond %{QUERY_STRING} !^loggedout=true     RewriteCond %{QUERY_STRING} !^action=rp     RewriteCond %{HTTP_COOKIE} !^.*wordpress_logged_in_.*$     RewriteCond %{HTTP_REFERER} !^http://maps\.googleapis\.com(.*)$     RewriteRule ^(.*)$ - [F]      # Rules to help reduce spam     RewriteCond %{REQUEST_METHOD} POST     RewriteCond %{REQUEST_URI} ^(.*)wp-comments-post\.php*     RewriteCond %{HTTP_REFERER} !^(.*)mywebsite.com.*      RewriteCond %{HTTP_REFERER} !^http://jetpack\.wordpress\.com/jetpack-comment/ [OR]     RewriteCond %{HTTP_USER_AGENT} ^$     RewriteRule ^(.*)$ - [F] </IfModule>     Let's consider that rewrite engine is not enabled in the host provider. I got the same result in my localhost. In localhost I have several other projects that use rewrite rules extensively. In wordpress I get 404 Not Found


Young man discovers his home "world" is a spaceship

I hoping for some help here, as Google isn't being useful... In my early teens I read a novel about a young man who is quite adventurous in his society and in climbing and adventuring into the off-limit areas of his world, discovers his "world" is actually a giant spaceship (possibly an asteroid ship) transporting a colony to a new world and it is very near it's destination after hundred or thousands of years. Problem is that it has been so many generations now that no one even knows this is a ship any more, so he has to finish the journey himself, possibly with the help of an AI in the ship (sorry, memory is really foggy).   Biggest problem is that is about all the details I can remember... This would have been about the mid-1980's and in paperback.   This image by Roy Scarfo is what brought back my memory of the book, I am guessing the cover art of the novel was similar in some way.


Science Fiction book with Three Part individuals

All I can really remember is that an alien species has three member "individuals" and that three humans go to their home world posing as figures from the aliens' mythology.  As humans are a complete entity in and of themselves, this race is only considered complete when all three biological pieces are present together and acting in concert. A single biological entity acting on its own is considered aberrant.


Prove the identity combinatorially $\sum^{n-1}_{i=1} i = \frac{n(n-1)}{2}$

I know the RHS is ${n}\choose 2$ and I'm suppose to think to the LHS as a pair but I'm not sure how exactly I'm suppose to decomposition it


Limit of the ratio of consecutive Fibonacci numbers

I have read in a book that the limit of the ratio of consequent Fibonacci numbers is the golden ratio. However, it was just mentioned thus not justified. So, my question is how would you derive the following limit: $$\lim_{x\to\infty}{\frac{F_n}{F_{n+1}}}=?$$ Where $F_n$ is the nth Fibonacci number?


Where to point the browser to when using Virtual Host?

When using Virtual Host, where should I point my browser to?  I'm trying to set up Virtual Host for Example.com. My understanding is that if all good, I have to point the browser to Example.com/phptest.php in order to access page phptest.php. But it's not working. On the other hand, if I point the browser to localhost/phptest.php, it is returning the phptest.php page.  The pertaining directory/files structure is as below.  ls -l /var/www/html/example.com/public_html total 12 -rw-r--r-- 1 ubuntu ubuntu 203 Nov 25 14:49 index.html -rw-r--r-- 1 ubuntu ubuntu  21 Nov 25 18:56 info2.php -rw-r--r-- 1 ubuntu ubuntu 641 Nov 25 13:48 phptest.php   Any help will be appreciated.


Finding a permutation to satisfy given condition

In $S_n$ with n=10, find a permutation $a$ such that $axa^{-1} = y$ if $x=(1,2)(3,4)$ and $y=(5,6)(3,1)$  I don't know how to start doing this. I read something like I need to get, for this case, $$(a(1),a(2)) \qquad \mbox{ and} \qquad (a(3),a(4))$$ but I am not sure where will I get their equivalents. Also, will those be my permutation $a$? Please help. I have problems very similar to this.


I stumbled upon something that for the time being looks really weird to me. Maybe i have been looking at it for too long and too up-close, so i am counting on your fresh pair of eyes and, of course, expertise.  I have a list that i want to update, namely ply_info. The update consists of getting an element from the list (the one pointed by sign_reversal_index), duplicating it and adjusting the values of the original and copy-cat entries. This final bit is the weird one and takes place at the two last lines of code.  ply_info = [[0.3], [0.13], [0.13], [0.3], [0.13], [0.13], [0.3], [0.3], [0.3], [0.3], [0.3], [0.3], [0.3], [0.3], [0.3], [0.3], [0.3]] t_ply = [0.3, 0.13, 0.13, 0.3, 0.13, 0.13, 0.3, 0.3, 0.3, 0.3, 0.3, 0.3, 0.3, 0.3, 0.3, 0.3, 0.3]  height_list = [0] for i in range(len(t_ply)):     height_list.append(height_list[i] + t_ply[i])  mid_plane_z = sum(t_ply) / 2  if mid_plane_z not in height_list:     print("...No ply boundary lies on mid plane.\n   ...Splitting the one that crosses it.\n")     height_list.append(mid_plane_z)     height_list = sorted(height_list)     sign_reversal_index = height_list.index(mid_plane_z)     ply_to_duplicate = ply_info[sign_reversal_index-1]     ply_info.insert(sign_reversal_index-1, ply_to_duplicate)     ply_info[sign_reversal_index-1][0] = height_list[sign_reversal_index] - height_list[sign_reversal_index-1]     ply_info[sign_reversal_index][0] = height_list[sign_reversal_index+1] - height_list[sign_reversal_index]   I debugged the thing and it looks like the two entries are somehow linked and updating the one, updates the other too. Both values get updated twice, once in the second to last and once in the last line of code. Can anybody please explain why something like that is happening and how it relates to the creation of the copy? what would be the way to go about\around this?  the correct output would be:  [[0.3], [0.13], [0.13], [0.3], [0.13], [0.13], [0.3], [0.3], [0.3], [0.19], [0.11], [0.3], [0.3], [0.3], [0.3], [0.3], [0.3], [0.3]]   notice the ...,[0.19], [0.11],...   Instead I am getting ...,[0.11], [0.11],...


Question on the Prime Number Theorem (the Tchebychev Function)

This has been giving me nothing but a headache:  Let the Tchebychev Function, $\psi (x)$ be defined:  $$\psi (x) = \sum_{p^m \le x}\log p \space \space \space , \space \space \space p \in \mathbb P$$  Prove that the integrated Tchebychev Function, $\psi_1 (x)$, is as follows:  $$\psi_1 (x) = \frac{x^2}2 - \sum_{\rho}\frac{x^{\rho + 1}}{\rho(\rho +1)} - E(x)$$  Where $\rho$ is a zero of the Riemann Zeta Function in the critical strip and:  $$E(x) = \left(\frac{\zeta ' (0)}{\zeta(0)}\right)x + \left(\frac{\zeta ' (-1)}{\zeta(-1)}\right) + \sum_{k=1}^{\infty}\frac{x^{1-2k}}{2k(2k-1)}$$  Can anyone point me to the right direction? Not really sure where to begin. Thanks!


Why does $\lim_{n\to\infty} \frac{n!}{(n-k)!n^k}$ equal 1

Came across this in my maths book.  $$\lim_{n\to\infty} \frac{n!}{(n-k)!n^k} = 1$$  Why is it so?


As a feature request, I would ask that you please add support for iPhone X.   Currently the app doesn’t use the entire screen. This would be immensely helpful.


When Alfred cries in front of Gordon at Bruce Wayne's funeral, was he faking it?

In the Dark Knight Rises during the ending scene, we see that Alferd is crying in front of Gordon and Blake at Bruce Wayne's Funeral. After sometime we see that Alferd sees Brue Wayne and Selina Kayle at a place (as he had imagined once). So I want to know that when did Alfred come to know about the reality of Bruce's death?  Had he known it all before because if that is the case then his crying at funeral was just a mask to fool Gordon and Blake.  Or is it that at that time he genuinely believed that Bruce is dead and only later he came to know that he is alive and where to find him?


What regression model is the most appropriate to use with count data?

I am trying to get a little into statistics, but I am stuck with something.  My data are as follows:  Year   Number_of_genes 1990          1 1991          1 1993          3 1995          4   I now want to build a regression model to be able to predict the number of genes for any given year based on the data. I did it with linear regression until now, but I have done some reading and it does not seem to be the best choice for this kind of data. I have read that Poisson regression might be useful, but I am unsure what to use. So my question is:  Is there a general regression model for this kind of data? If no, what do I have to do to find out which method is the most  appropriate to use ( in terms of what I have to find out about the data)?


macOS Sierra keeps running out of application memory

Every time I turn my Mac on, after a while the app memory just runs out.      These are just from 10min apart, after working for a while. I need help figuring what those Installers are and why the kernel_task is taking so much memory. Those Google Chrome Helpers also look extremely unnecessary.  The only thing that 'solves' this is restarting the computer. How can I get rid of this cycle?


Limit of Integral of Difference Quotients of Measurable/Bounded $f$ Being $0$ Implies $f$ is Constant

Assume $f$ is Lebesgue measurable and bounded on $[0,1]$ and that $$\int_{0}^{1}\frac{|f(x+h)-f(x)|}{h}\;dx\to0\;\text{as}\;h\to0.$$ Show that $f$ is constant for almost every $x$ in $[0,1]$.  My question relates to my proposed proof below.  At no point did I rely on the boundedness of $f$ on $[0,1]$, only its measurability and so I suspect my reasoning is faulty and would appreciate somebody that could (in their answer) scrutinize and correct my proof.  (Proposed) Proof. Assume first that $h\to0^{+}$ and suppose that we may interchange the two limits.  Then since the difference quotients are non-negative, we conclude $f'(x)$ exists and is equal to $0$ for almost every $x$ in $[0,1]$, and the claim follows. (As pointed out, we don't necessarily know the limit of the integrands exists even when we assume the interchange is valid, although this is probably not difficult to reason one's way out of -- more damning is below.)  The goal quickly turns to justifying this interchange.  To that end, the presumed existence of the above limit implies that for any $0<M<\infty$ there is some positive real number $h(M)$ such that for any $h<h(M)$ we have $$\left|\int_{0}^{1}\frac{|f(x+h)-f(x)|}{h}\;dx\right|<M.$$ Since $m([0,1])=1$ (in particular, we are integrating over a set of finite measure) and the difference quotients are non-negative, we conclude that $$\frac{|f(x+h)-f(x)|}{h}<M\;\text{a.e.}\;x.$$ Since this bound is independent of $h$ once $h<h(M)$, it follows that at some point along the sequence each of the difference quotients is pointwise a.e. dominated by $M$, which is integrable on any set of finite measure.  Hence the interchange of limits discussed above is valid, and with the case of $h\to0^{-}$ being handled similarly, the claim is proved.   (As the comment points out, we cannot conclude anything about the upper (or lower) bound of a function based off the value of its integral, even if the integration is taken over a set of finite measure and the integrand in question is nonnegative; approximations to the identity serve or otherwise spikey functions on sets of small measure as counter-examples.)    Edit. Fatou's lemma implies $$\int_{0}^{1}\liminf_{h\to0}\frac{|f(x+h)-f(x)|}{h}\;dx\leq\lim_{h\to0}\int_{0}^{1}\frac{|f(x+h)-f(x)|}{h}\;dx=0.$$  Hence $$\liminf_{h\to0}\frac{|f(x+h)-f(x)|}{h}=0\;\text{a.e.}\;x.$$ (The $\liminf$ of course exists without further justification.)  We now need a way to obtain the same for $\limsup_{h\to0}\frac{|f(x+h)-f(x)|}{h}.$  This could be accomplished by showing the limit exists under the assumptions given, in which case the $\liminf$ is equal to the $\limsup$.  Any ideas how to execute this, or otherwise approach the problem?  I'm wondering too if my original argument above could be modified by taking into account the assumed boundedness of $f$ in order to exclude the possibility that its difference quotients form a "spikey" sequence of integrands.    Edit. Here is another approach I am considering by posting this question   Peter Tamaroff mentioned the type-writer sequence being a counter-example to the post linked.


"approach to address" or "approach to addressing"?

Depending on our point of view, we offer different approaches to address(ing?) a same issue.   Should I use —ing in this context, and if yes, why?


This  article states that laser beam width changes along the length of the ray (the function stated doesn’t look like it could be a constant 1)  Is it impossible to create optics that completely parallelize laser light? If not, why so?


Tool Dialogs appear blank in ArcGIS for Desktop?

All of a sudden my Toolbox in ArcGIS 10.1 for Desktop has stopped working.  Last week i was using clip tool but the toolbox window was blank, i tried other tools but it shows the same blank window.


Which is the right answer?         There isn't any money in the pot.     There isn't money in the pot.     There aren't money in the pot.     There are money in the pot.


Is it possible to use USB output and audio port output at the same time?

I want to use two headphones simultaneously; one USB and another through the audio port listening to the same audio source (i.e iTunes, Spotify, or Netflix) at the same time. Is it possible?   Info about my device,   MacBook Pro (Retina, 13-inch, Early 2015)   2.9 GHz Intel Core i5   OSX El Capitan 10.11.6


MySQL Workbench not working in Ubuntu 20.04

When I upgraded the ubuntu 19.10 to 20.04,MySQL Workbench not show in the system.Then I installed the MySQL Workbench community & run it then.It gives a below error.How can I resolve it?


Choice of Gerund or infinitive as subject of a sentence

In a multiple choice exercise I had to choose between:  .................... is banned in all pubs in Ireland.  A/ To smoke  B/ Smoking  I'm pretty sure the solution is B (Smoking) but I don't really know the rule behind. Could somebody please explain why it is B (if so)?


In the Upcoming Halloween Update Posted By SOOPUR SELL (supercell), there have been sneak peeks released showing new skeleton traps for TH 8+. I also remember the Santa Strike from one of the Christmas Updates. My question is when these holiday events finish, do we lose the money we spent on the Traps or do we keep them forever?


Python reading of a file stops before it should in Windows 7

I am using Python to open the physical disk in the computer to read the first sector.  disk = r"\\.\PhysicalDrive0" with open(disk, 'r') as f:         f.seek(0)         partdata = f.read(512) len(partdata)   In windows XP len(partdata) will return 512 and have the correct content. In windows 7 len(partdata) returns 230 and the data is correct until it breaks off.  Also, trying to seek farther into the disk doesn't work and it only returns the first 230 bytes.  Python versions 2.7.1 and 2.7.2 32bit and 64bit  On Windows 7, one 32bit machine one 64bit.


bash script var not changed after the loop

I'm quite new to bash scripting, and I wrote the following script to emulate the wc -c command: (I know it doesn't count the end of the line)  #!/bin/bash  echo $1 len=0 cat $1 | while read line do     let len+=${#line}     echo $len done echo $len   the output is the following:  xyz.sh 11 11 18 27 51 53 70 79 83 92 0   why doesn't len stays changed after the loop, and hoe to make it to do so?


If $f^2$ and $f^3$ are $C^{\infty}(\mathbb R)$ then $f$ is $C^{\infty}(\mathbb R)$

Since it is an exercise from an oral exam, I have added some indications I had.  $f : \mathbb R \to \mathbb R$, such that $f^2$ and $f^3$ are $C^{\infty}$, show that $f$ is $C^{\infty}$.  The two isolated hypothesis are not sufficient, since there is a problem in zero for the cube root, and since you can take $f$ that takes $1$ and $-1$ without regularity but its square will be constant.  How to proceed with the two hypothesis?    Here, the indications I have from the candidate who has taken the oral exam:  -First, show that $f$ is $C^1$: Suppose $f(0) = 0$ (it is exactly the problem, and by translation we consider that it is in $0$). Suppose they exist and use the Taylor expansions of $f^2$ and $f^3$ up to a non-zero order. Find a polynomial link between both coefficients using equivalents. If they do not exist, $f^2 =o(h^4)$ so $f$ is $C^1$ in $0$ (?).  -Use the general Taylor expansion (with integral remain) for $f^3$.  Suppose the coefficients are not all zeros, (change the bounds to $0$ and $1$), show that the parameter integral is $C^{\infty}$, then take the cube root (??).


Should I symlink my /var/www directory to my home?

I have just installed Ubuntu Server 10.04 with a LAMP setup.  I want to host a website there but I'm not sure which is the best way to get/edit my files on the server.  Googling provides many options but I'm not sure which is best?  Unless there's a better option, I'd like to be create the pages on another PC (Windows or Linux) and use SFTP to sync the changes to the server - but do I do this to a symlinked folder in ~/ or by changing rights on the /var/www/ folder?


Example of a convergent pointwise sequence of function and not uniformly convergent

We say that a sequence $f_n(x)$ is pointwise convergent to $f(x)$ on the set $E$ when for every $x\in E$ and $\epsilon >0$ there exists an integer $N$ such that  the distance between $f_n(x)$ and $f(x)$ is smaller than $\epsilon$. We say that a sequence $f_n$ is uniformly convergent to $f$ on the set $E$  if for all $\epsilon >0$ there exists an integer $N$ such that  the distance between $f_n$ and $f$ is smaller than $\epsilon$. The main difference between the aforementioned definitions is that $N$  dependant on $x$ in the context of pointwise convergence, that is for each $x$ in $E$ there exists a specific $N$ associated to $x$ while in the case of uniform convergence there exists a universal $N$ for which the $f_n(x)$  converges to $f(x)$ uniformly with respect to $x$. Can you please give me an example of sequence of function that converges pointwise and not unifomly to $f(x)$. Thanks in advance


How to export 3D model unity Correctly with textures

I made a 3D model for Unity. I tried to export it to Unity using the fbx format and some other formats, but every time I tried to export it the material would not show up. Instead the 3D model shows up as one color, black. Thank you, fellow humans.


Transforming data with large negative and large positive values

The data I'm trying to analyze are the quadratic estimates from a quadratic fit to a curve.  Most of the data vary between -.15 and .15.  However, I have outliers in both directions up to things like -23.00. Outlier analysis and removal has been deemed insufficient as the primary coping method.  Therefore, I need to transform the data; I wanted to use a log transformation but adding a constant to the data seems sketchy (it would have to be a large constant to cover all extreme outliers).  Any suggestions as to what kinds of transformations might work here?  I need normally distributed data in the end so that I can run ANOVAs.


"The bass drop is so sick!..." - What does it mean?

Being a fan of a dubstep music, I often see comments like this:     "Looooove this tune! The bass drop is so sick!..."   To my understanding, sick has negative connotation. Merriam-Webster  this word as "affected with a disease or disorder", either physically or mentally.  However, the phrase above looks rather positive (even if followed with something like "...my ears were bleeding").  What's the point?


Get last n lines of a file, similar to tail

I'm writing a log file viewer for a web application and for that I want to paginate through the lines of the log file.  The items in the file are line based with the newest item at the bottom. So I need a tail() method that can read n lines from the bottom and support an offset.  This is hat I came up with: def tail(f, n, offset=0):     """Reads a n lines from f with an offset of offset lines."""     avg_line_length = 74     to_read = n + offset     while 1:         try:             f.seek(-(avg_line_length * to_read), 2)         except IOError:             # woops.  apparently file is smaller than what we want             # to step back, go to the beginning instead             f.seek(0)         pos = f.tell()         lines = f.read().splitlines()         if len(lines) >= to_read or pos == 0:             return lines[-to_read:offset and -offset or None]         avg_line_length *= 1.3  Is this a reasonable approach?  What is the recommended way to tail log files with offsets?


I was recently asked this question in an interview, but was completely stumped as to how to even begin answering it - it's been bugging me ever since, and I thought it was quite a nice question, so hopefully someone on here can help me out. Any help would be appreciated! Here goes:  You start off with £100 and you toss a coin 100 times. Before each toss you choose a stake $S$ which cannot be more than your current balance $x$ (so your maximum stake for the first toss is £100). If the coin comes up heads, you win $2S$ and your new balance is $x+2S$. If it comes up tails, you lose your stake and have $x-S$. How do you choose your stake so as to maximise your expected winnings from the game, not including the initial balance?  Cheers,  Boris


Does Hextech's "reroll" function consider the skin type as result?

If I reroll 3 skins of the same type, say 3 legendary skin shards, will I get a different legendary skin shard, or literally any random skin?


Is there a software to automatically crop a scan of multiple images? ( Windows 10 )

I want to digitize my old family albums using a scanner and there are lots of photos in them. Thus far, my method has been to scan 4 images at a time and then manually cropping them in a simple editor like paint 3d. This has been pretty time consuming as each scan is followed by 4 crop operations. Scanning each image individually would possibly be even more time consuming. I'm on windows 10. Is there any software (other than photoshop) or simple plugin that does this job?


How big is my single pattern in Photoshop

I pulled a repeating pattern from someone else's PSD. Is there a way to figure out the size of the original pattern? I need to create an image with only one tile.


Is it safe to eat chicken stored below 0c for about 8 days? If not what are the dangers?

Suppose I left some chicken in the freezer for 8 days and the freezer was set to go from 0c to -5c over those 8 days. Since the air temperature was still below 0, is it safe to eat that particular chicken? As far as I'm aware, bacteria only becomes a problem at higher temperatures. If not safe what might the problems be?


There is a  that didn't receive a proper answer. How can I find a security group's dependencies?  These include EC2 instances, but other services also create dependencies, like the load balancer and even relationships with other security groups. Is there a way to systematically list every single dependency?  Thanks!


Problem with declaring new command containing number

I am trying to declare a new command using the following string:  \newcommand{\to8}[1]{\xrightarrow{\mathmakebox[0.8cm]{#1}}}   but the compiler returns many errors.  I just don't understand why if I write  \xrightarrow{\mathmakebox[0.8cm]{iiiii}}   in the math mode the compiler returns no error but the compile does not allow it when I want to define it as a new command?


Elegant or elementary evaluation of $\lim\limits_{x\to 0} \left( \frac{1}{x}-\frac{1}{\sin(x)} \right) $

I give math tutoring and was wondering about the following limit. I found the answer but I was wondering if someone has a nicer explanation than the one I am giving where I use L'Hôpital's rule twice. The limit I am evaluating is: $$\lim\limits_{x\to 0}    \left( \frac{1}{x}-\frac{1}{\sin(x)}   \right)  = \lim\limits_{x\to 0} \frac{\sin(x)-x}{x\sin(x)}  $$ Both numerator and denomitor go to zero here so we may use l'Hôpital's rule here. The limit is thus equal to: $$\lim\limits_{x\to 0}   \frac{\cos(x)-1}{\sin(x)+x\cos(x)}   $$ Again numerator and denominator go to zero and thus by l'Hôpital the limit is equal to: $$\lim\limits_{x\to 0}  \frac{-\sin(x)}{\cos(x) + \cos(x) + x\sin(x)}$$ Now we are looking at the limit of the quotient of two everywhere continuous functions where the denominator is not zero. Thus the function itself is continuous and so the limits is: $$\lim\limits_{x\to 0}  \frac{-\sin(x)}{2 \cos(x) + x\sin(x)} = \frac{0}{2}=0$$  Does anyone know a more nicer, more elementary way of solving this? Thanks!  EDIT: Also, if anyone knows a fast, yet less elementary way to solve I would enjoy seeing it so feel free to post :)


Best Way to (truly) Reduce Gradient Banding in Photoshop across ALL Monitors

This problem keeps coming up again and again. I have tried to use the Dither checkbox in a Layer Effect in Photoshop CS6+ but that doesnt always work so well.  And applying a grain effect or noise effect just looks horrible sometimes.  It might be that I am not doing this correctly so would love feedback or leads to online tutorials that really solve this issue.  NOTE: I am preparing graphics strictly for web — so need to make gradients smooth in all displays including Apple Thunderbolt Displays, iPhone, iPad and even crappy monitors with low color gamuts.  Thanks


$11^{10} \equiv 1 \pmod{100}$  I tried to solve by using euler's theorem, But I got stuck.  $\gcd(11, 100) = 1$  $11^{φ(100)} \equiv 1 \pmod{100}$  $11^{40} \equiv 1 \pmod{100}$  I don't know how to go on as $11^{40}$ is bigger than $11^{10}$


What's the best way to restore a deleted file from a package in debian?

/etc/sudoers had been deleted, and I wanted to restore the default file from the package. I tried:  apt-get install sudo apt-get install --reinstall sudo apt-get remove sudo && apt-get install sudo  None of which worked but all of which warned about /etc/sudoers not existing.  In the end I did apt download sudo && ar xv sudo && tar xf data.tar.xz ./etc/sudoers and just copied that file to /etc/sudoers, but was there a more straightforward way to restore the file?


If I cast  and my opponent chose money, if I were to target their , can I attack with it immediately?


Given correlation and linear relationship between x and y find a linear relationship with the variables switchrd

This is probably a really obvious question, but I don't see the explanation.  We have a population of $(X, Y)$ pairs for which $\rho_{XY}=\rho$ and $Y$ is given by the linear representation $Y = \alpha + \beta X + e$ where $\operatorname{Cov}(X,e)  = 0$.   What is the best linear representation of the relation between $Y$ and $X$ with the variables reversed: $X = \gamma + \delta Y + u$. Specifically what would $\delta$ be in terms of $\alpha$ and $\beta$?


As far as I know, perpetual motion orbital desktops like below use an electromagnet in the base.    Why aren't permanent magnets used on both ends instead?  Does anyone know where I could find a teardown of the base of a generic one?


I have been trying to get pdfLaTeX, Beamer, and PSTricks to be friendly. The following code compiles without hiccup, and a pics.pdf file containing my diagram is created, but the output presentation is completely blank.  \documentclass{beamer} \usepackage[pdf]{pstricks} \begin{document} \begin{frame} \begin{pspicture}(1,1) \psline(0,0)(1,1) \end{pspicture} \end{frame} \end{document}   Thanks in advance for your help.


Is $v=\ (r_i)^{-1}\cdot z $, a uniformly random value of a field?

We consider a finite field $\mathbb{F}_q$ where $q=2p+1$ and $q$ and $p$ are prime numbers.  Let $r_i$ be a value picked uniformly at random from the field such that $r_i>\frac{q}{2}$. Let $z$ be a fixed field element.   Question: Is $v=(\ (r_i)^{-1}\cdot z) \bmod q$, a uniformly random value of the field?


How do you prove the eigenvalues and eigenvectors of matrices are the same?

I wondered if anyone could help me with a couple of proofs.  The question is: Let $A$ be a given $n \times m$ matrix. The collection of scalars $\lambda_i$ and associated $n \times 1$ vectors $q_i$ that solve the equation $Aq=\lambda q$ are known as eigenvalues and eigenvectors of $A$, respectively show that:  i. Suppose $n=m$. Then for any non-singular $n \times n$ square matrix $G$ the eigenvalues of $G^{-1}AG$ are the same as those of $A$.  ii. If $A^{-1}$ exists then it shares the same eigenvectors $q_i$ as $A$ with corresponding eigenvalues $\lambda_i^{-1}$  Thanks in advance!


Is it true that $\mathbb{R}$ and $\mathbb{R}^2$ are isomorphic as abelian groups?

I think the answer is yes.   Sketch of the proof Consider $\mathbb{R}$ as a vector space over $\mathbb{Q}$. Let $\{e_\lambda:\lambda\in\Lambda\}\subset\mathbb{R}$ be its Hamel basis. Then $\{(e_{\lambda_1},e_{\lambda_2}):\lambda_1,\lambda_2\in\Lambda\}\subset\mathbb{R}^2$ is a Hamel basis of $\mathbb{R}^2$. Consider set theoretic bijection $i:\Lambda\to\Lambda\times\Lambda$ define map $\varphi:\mathbb{R}\to\mathbb{R}^2$ by its action on element of Hamel basis of $\mathbb{R}$ by equality $\varphi(e_\lambda)=(e_{i(\lambda)_1},e_{i(\lambda)_2})$. This is an isomorphism between $\mathbb{Q}$-vector spaces $\mathbb{R}$ and $\mathbb{R}^2$.  Question Could you tell me is this proof correct, and if it is not, where is the mistake?  EDIT: Thanks to GAJO we found that this proof is wrong. The correct one basis is  $$ \{(e_\lambda,0):\lambda\in \Lambda\}\cup\{(0,e_\lambda):\lambda\in\Lambda\} $$ So we had to look at bijections of the form $i:\Lambda\to\Lambda\coprod\Lambda$ and the desired linear operator is defined by equalities $\varphi(e_\lambda)=(e_{i(\lambda)},0)$ if $i(\lambda)$ lies in the first copy $\Lambda$ and $\varphi(e_\lambda)=(0,e_{i(\lambda)})$ otherwise.


Program figuring out if a number entered is even

I need to make it so the computer figures out whether an int somebody entered is even or not. How would I prove that? I tied just dividing it by two, but that isn't a boolean, and I don't know how I would figure it out with booleans either. Also would I need a separate counter to count the evens?  import java.util.Scanner;  public class evenNumber {  public static void main(String[] args) {  Scanner scan = new Scanner(System.in);  int numberOne = 0;    for(int counter = 0; counter < 15; counter++)    System.out.print("Enter a number: ");    numberOne = scan.nextInt();    if(numberOne/2  ){    }  } }


Objects partially hides when are modeled in full size. These ar 900mm high. It happens in every view.


Find a recurrence relation for the number of $n$-digit binary sequences with no pair of consecutive $1$s.  I know my base case:$$a_1 = 2$$ for either $1$ or $0$. Normally to construct the recurrent relation I would say fill in $n-1$ spaces then add a $1$ or $0$, which is simply:$$a_n = 2\cdot a_{n-1}$$However, I don't believe this is right, because this doesn't take into account that there can't be any consecutive $1$s.  Even when I use the base case of $2$ digits:$$a_2 = 3$$for either $01$, $10$, or $00$, I still get the recurrence relation of:$$a_n = 3\cdot a_{n-2}$$which also does not account for $01$ and $10$ occurring consecutively.   So how would I express this?


Evaluating $\int \sin^2 x \cos^3 x \operatorname dx$

$$\int \sin^2 x \cos^3 x dx$$  $$\int (1-\cos^2 x) \cos^3 x dx$$  I know there is a rule in my book (with little explanation) that tells me when I had an odd and an even degree on two trig functions I should split the odd and convert it to an identity but this way seems easier, and I can't get an answer either way.  $$\int \cos^3 dx - \int \cos^ 5 x dx$$  I am not sure where to go from here, I don't know how to get the integral of $\cos^3 x$


Field of view using 50mm APS-C lens on APS-C body vs 50mm FF lens on FF body?

I am taking 2 pictures using:     Nikon D3400 APS-C sensor and an APS-C kit lens, 18-55mm set at 50mm   Nikon D850 full frame camera and a full frame lens 50mm that is designed for full frame Nikon camera   Both systems have lenses mounted on them that is specifically designed for them. I am NOT putting FF lens on APS-C camera nor I am putting APS-C lens on FF camera. Shouldn't both 50mm images taken by above 1 and 2 have same field of view? What am I not getting here? Please clarify.


How do I install openjdk 7 on Ubuntu 16.04 or higher?

I would like to upgrade my main system to 16.04, but I work on projects that require OpenJDK 7.   Apparently it is not available from a trivial apt-get install openjdk-7-jdk. Only versions 8 and 9 are listed in the repository.  Can anyone point me to instructions on how to install it?


.iterator() Producing Null Pointer Exception Even When Checked For Null

I am doing some threading. In the postExecute I need to perform an iterator task. I check if the iterator() is null, but it's still producing this error:  java.lang.NullPointerException: Attempt to invoke interface method 'java.util.Iterator java.util.List.iterator()' on a null object reference         at co.appname.app.Fragments.F_EditPhoto$FiltersAsyncTask.onPostExecute(F_EditPhoto.java:772)   Here is my code, Im checking for what I think is every possible null scenario. Can you advise what I am doing wrong?  @Override         protected void onPostExecute(Void aVoid)         {             List<K_FilterPreview> filtersCache = _positionToFiltersCacheMap.get(_selectedEditImage.position);             if (filtersCache == null || filtersCache.iterator() == null)             {                 System.err.println("Filter cache was null");             }              // THIS IS THE LINE THROWING THE ERROR!             Iterator<K_FilterPreview> i = filtersCache.iterator();             while (i.hasNext())             {                 //Do stuff             }         }   This only occurs if I try to start this event as soon as the current event is done processing. If I wait a few seconds before invoking this it works fine. So there is something going on with the threading but I'm not sure what.


null object reference on Animation rotation = AnimationUtils.loadAnimation(getContext(), R.anim.rotate);

I have created a fragment in which an animation for rotation is there.      Animation rotation = AnimationUtils.loadAnimation(getContext(), R.anim.rotate);   When loading the fragment for the first time the animation is finely loaded.  But when coming back to the activity from another activity using intent, it loading the activity fine, loading the fragment fine but giving      Attempt to invoke virtual method 'android.content.res.Resources android.content.Context.getResources()' on a null object reference   pointing     Animation rotation = AnimationUtils.loadAnimation(getContext(), R.anim.rotate);   Please help. Thanks in advance.


Suppose that $G$ is a group and $H$ is a subgroup of finite index in $G$. Then can I find a subgroup normal $N$ of $G$ such that $N\subset H$ and $[G:N]$ is finite? Further, I would like to find an upper bound on $[G:N]$. I would a appreciate a hint.


Switching data source of layer to new feature class using ArcPy with ArcGIS Pro 2.0?

A common ArcPy coding pattern that I used with ArcGIS Pro 1.4 (and earlier) no longer works at ArcGIS Pro 2.0.  I have an ArcGIS Pro project with one map called Map, and that map has one layer called Test Layer.  Test Layer has as its data source a file geodatabase feature class called testFC.  I have used the Select tool to create a new feature class called testFC2 which is a subset of testFC (so it has an identical schema).  In ArcPy at ArcGIS Pro 1.4 I had no trouble switching the data source of Test Layer from testFC to testFC2 in the same file geodatabase using this code:  import arcpy aprx = arcpy.mp.ArcGISProject(r"C:\temp\test.aprx") mapx = aprx.listMaps("Map")[0] lyr = mapx.listLayers("Test Layer")[0] lyr.dataSource = r"C:\temp\test.gdb\testFC2"   However, the same code at ArcGIS Pro 2.0 gives:     AttributeError: can't set attribute   I checked the  and that now says that the dataSource property is now Read Only whereas previously it was Read and Write.  The same help page says:     Changing a layer's data source is a common requirement. There is a   method and a property on the Layer object that help with this. For a   more detailed discussion, parameter information, scenarios, and code   samples, please refer to the    help topic.   I can find no suitable code sample to use in place of my coding pattern at  which seems to be focussed on switching workspaces of data sources.  How do we switch the data source of a layer to a new feature class using ArcPy with ArcGIS Pro 2.0?  The same issue seems to have been noted at  where Marco Boeringa says:     The "dataSource" property of the Layer class also seems to have become   Read Only. However, you can use the "updateConnectionProperties" on   the same class to solve this   However, I think his situation must have been slightly different because I cannot see how updateConnectionProperties can be used to answer my question above.


My child's surname has changed and he has a new passport, but the B2 visa has his old surname. Can we travel with the two passports and the documents that show his surname change?


Is $\|A^n\|=\|A\|^n$ true for any normal operator in a Hilbert space?

Does anyone have a reference for the fact that if A is a normal operator on a Hilbert space the $\|A^n\|=\|A\|^n$? I have managed to prove this fact using a hint on another question, but I need an actual bibliographical reference, please help.


Still able to read file after changing permissions

I've made a file as root, and written a string in it. Now I've changed mode to "0" like this:  root# ls -al transit/ total 4.0K ---------- 1 root root 6 Jan  5 18:15 27050 root#   If I try to tail, head, or cat it, it works:  root# cat transit/27050 320646 root#    Why is it possible to read it?


Shouldn't there be any way of reviewing the edit reviews?

Sometimes my edits are rejected for no good reason. A good example is when I add a new major tag (like asp.net) to the question, and the edit is rejected for being a too minor edit. Adding an asp.net tag is not a minor edit. Everyone should know that.  By the way, this question does not have anything to do with the one suggested here. The only thing I can think of they have in common are the words "review" and "audit". That question is asking what audit reviews are, but my question is actually a suggestion on having a guideline for reviewing edits, or having an audit of edit reviews.    Note this question , but is essentially different:   As opposed to above question, this one is asking if there's a way to review reviews. The goal is the same as review audits (to improve the quality of reviewers), but the mechanism is different. Also, review of reviews is an active mechanism and review audit is a passive mechanism.  To put it simply, let edits be E and reviews be R. Review audits is still reviewing E (except that the E is not a real edit), whereas here I am asking whether there is anything to review R.


What chapter of the Seven Deadly Sins manga is Episode 20?

Alright so I am caught up with the anime but cannot wait for the next episode (currently on episode 20). What chapter would match the anime?


Analog circuit for multiplying in the frequency domain

I have an idea I want to experiment with - doing boolean logic with analog (OFDM) signals. Each frequency component represents a different 'bit'. A key factor is performing the AND operation. I would like to be able to multiply the frequency domain of two signals (aka convolution), e.g.   $$A(ω)B(ω) = X(ω) \leftrightarrow a(t)∗b(t) = x(t)$$  Essentially, the frequency response of one signal is used to filter the other signal. If A is a superposition of 100, 200, and 400 Hz sines, and B is 200,300, and 400, the output would be 200 and 400 Hz.   Is there a circuit to perform this operation? I know I can multiply the time domain signals with something like a Gilbert cell. Digitizing and using DSP would completely defeat the purpose, I would like to do this solely with hardware (and ideally the simplest circuit possible).  Note: I read  before posting this. It does not really have any satisfactory answers (except delay lines, which I've been looking into). Also, I might be able to get by with just being able to very rapidly (~1Ghz) adjust the center frequency of a bandpass filter.   To give a bit of clarity, what I am kind of looking to do is send multiple (i.e. 64) bits down a single trace of copper, frequency multiplexed. It would pass through assorted gates to make up an ALU. A 64-bit AND gate would only need 2 input traces and do frequency-wise AND. Max frequency is less important than bandwith.  Anything to help me move in the right direction would be great. CCD-based delay lines seem promising, but specific implementations / use cases would be most excellent.   Thanks!


How do I change the order of columns in a table? I have too many rows and doing this manually would be a horrible pain.  A MWE to get us going (let's get rid of Yoda!):  \documentclass{article}  \begin{document}  \begin{table}     \begin{tabular}{c c c c}         \hline \hline         this & in & order & is \\ \hline\hline         1    & 3  & 4     & 2  \\         a    & c  & d     & b  \\         \hline     \end{tabular}  \end{table}       \end{document}


Is it possible to measure the speed of Time?

Is it possible to somehow measure the rate at which time is passing?


What is actually $e$ ? Why $e$ is so significant over other real numbers ?

I had this question for a long time.   We always use it in differentiation,Integration , Logarithms ..etc.   What is its origin ?   What unique qualities does it have over other real numbers?


If $A$ is non-singular, prove $|A| = \frac{1}{|A^{-1}|}$?

I am unsure on how to prove the following problem:  If a $2 \times 2$ matrix $A$ is non-singular, prove $|A| = \frac{1}{|A^{-1}|}$  I know that $|A|\cdot|A^{-1}| = I$ but i’m not sure where to go from there. Any help on proving this would be appreciated.


Suppose one doesn't know any Galois theory, but they are familiar with the basic theory of field extensions. Then how would one justify the following picture?    I'm pretty sure they're just saying these are the known subfields, and there could be more but they just write down those ones (which seems weird, which is why I'm asking). Or have they deduced that this is a comprehensive list of subfields just by using basic theory? This occurs on page 573 of Dummit and Foote's Abstract Algebra.


I'm new to Apex and development in general... So, I'm playing around coding and doing some badges in Trailhead. I created a small piece of code, as below, and have no actual use: public class GenderIdentifier {     public void DetermineGender(String Gender){                 if (Gender == 'Man'){             Gender = 'Male';             } else {             Gender = 'Female';         }            } }  If I make the method 'non-static' it works, and I can see it working fine executing as a anonymous block. If I make it static, I can't execute the anonymous block, as I get an Error like:  Non static method cannot be referenced from a static context: void GenderIdentifier.DetermineGender(String)  What am I doing wrong? It would make sense to have a method like this as Static. I think I misunderstood the concept of static methods.


I know the eigenvectors of the Laplacian of a ring graph with $n$ vertices are  $$x_k(u) = \sin \left( \frac{2 \pi k u}{n} \right)$$  and  $$y_k(u) = \cos \left( \frac{2 \pi k u}{n} \right)$$  for $1 \leq k \leq \frac n2$. However, I can't understand which one is an eigenvector of the Laplacian of the ring graph. Actually, what is the value of the $i$-th element of the $j$-th eigenvector of the Laplacian of a ring graph with $n$ vertices?  I couldn't find anything that directly explains this issue.


How can I solve a far away stacking Freestyle line

Im a beginner to use blender for comic     i try a way to make line on faraway object to be small but it still have a result like this. their are the way or some easy method to make a stacking line look doesn't black like this?


Why serialVersionUID in java must be static, final, and of type long?

Why  must be declared as static, final and of type long variable? Does this serialVersionUID be unique?  What happens when two or more classes contains the same serialVersionUID? How will this versionUID be useful in this case to deserialize the byte array?


How do we know dark matter isn't curved spacetime?

Could Dark Matter actually just be spacetime with curvature "leftovers" from the big bang or the inflationary epoch?


I am running Ubuntu 15.04 on a Dell XPS 13 from 2013. Since 13.04 I sometimes get accidental middle clicks/middle click emulation. I can tell this is happening because text in my clipboard pastes itself (default behaviour on Ubuntu) at random times.  Can anyone tell me why this is happening and how I can disable it?


What happens when I hover over a link in Chrome?

When this link (http://a//%%30%30) is clicked in Google Chrome, Chrome breaks and closes all tabs and instances.   But, in some cases I only need to hover over the link, and the tab crashes.  What happens when I hover over this link? I mean, what does Chrome do when a link is hovered over?


A function $f$ such that $f' = 0$ when $x < 0$ and $f' = 1$ when $x \geq 0$?

Is there a differentiable function $f: \mathbb{R} \rightarrow \mathbb{R}$ such that $f'(x) = 0$ when $x < 0$ and $f'(x) = 1$ when $x \geq 0$?   Attempt: I was trying to think of an example. First thing that came to mind was $$ f(x) =  \begin{cases} x & x \geq 0 \\ 0 & x < 0 \end{cases}. $$ I wanted to know if it is differentiable at $x = 0$. Since $$ \lim_{x \to 0^+} \frac{f(x) - f(0)}{x} = 0 = \lim_{x \to 0^-} \frac{f(x) - f(0)}{x} $$ the derivative at $x = 0$ exists and equals $0$. But according to the problem, the derivative should be $1$, so I guess this is not a correct example. Does anyone have an example, or is such a function not possible at all?


I recently got a . I've been riding for a long time, but this is the first bike I've ever had with a carbon fork, and only the second I've had with a threadless headset.  The problem I'm having is that the stem keeps creeping up the steerer tube; this pulls the plug up as well. Every few days I need to tighten everything up, and tonight I noticed that the headset's upper cartridge bearing is loose in its race.  I am concerned about over-torquing the clamp bolts, but I'm doing it anyhow, because 5 nm just doesn't seem very tight. I've applied some carbon paste to the steerer, which seems to help a little, but it hasn't solved the problem. The stem (from Ritchey--not stock) has visible loctite on its bolts, but maybe they need more? It occurred to me that it might have a different stack height than the stock stem, and I've played around with headset spacers, but that doesn't seem to make a difference.


How is gamma ray blocked in the atmosphere in cosmic rays?

I would like to know how gamma rays from cosmic rays are blocked by the earth's atmosphere. I know that the sun's gamma radiation don't usually reach the earth so I wouldn't be worrying much about it. I have did some research and I only see that ozone will block uv radiation but not gamma radiation. So I am wondering how is gamma radiation being blocked by the atmosphere? What molecules in the atmosphere specifically absorb gamma radiation? Thank you!


Why are reboot, shutdown and poweroff symlinks to systemctl?

In Arch Linux, if I do ls -l in /sbin, I can see that reboot, shutdown and poweroff are all symlinks to /usr/bin/systemctl. But issuing reboot, shutdown and systemctl commands obviously does not all have the same behaviour.  Is ls -l not showing me full information regarding symlinks? How can I, for example, know what the real symlink of reboot is?


Can we expose class for badges in Data Explorer?

According to  the following metadata is exposed for badges:  Id UserId Name Date   Why isn't class exposed in some way? It's obviously in the schema, since we can sort / filter in the UI. Come to think of it the description might be something useful to filter on in a query as well, e.g.:     Give me the name and count for all gold badges that contain the word 'vote' in the description.   I am not sure if class is exposed in a different way for tag-related badges (I suspect the schema is more complex, since their existence relies on them having been awarded in that class at least once).  (Also, the Id in the Badges table is not the badge id, it seems to be an IDENTITY / auto-increment column.)


Vertical alignment of tags differs between Ask page and inline tag editor

If you are trying to edit tags, spans with tags are on the middle of block:        If you are trying to create new questions, top padding of this block is greater than bottom:        Alternately see them side by side (inline tag editor on the left,  on the right):         On question creation div, that surrounds spans with tags, has class multi-line. If you remove it, everything will be fine.


Does training a gym that you are a member of make it harder to take over?

I am a member of a level 7 gym. There are 2 Lapras, 2 Snorlax, 1 Arcanine, 1 Vaporeon, and 1 Pidgey. The current prestige of the gym is 25,432 / 30,000. The Arcanine joined and left the prestige at about 20,500. I trained (even though I'm already a member) to push the prestige to 25,432 so far. This sets a higher bar for someone who tries to conquer this gym, right? I'm not quite sure how it works.  Does this make sense? If I continue training and can push prestige above 30,000, then I've opened an extra defender slot, but I can't control who fills it. Someone walking down the street could notice this extra slot and join. I'd hope for a Dragonite, but I'll take any extra person to help defend.  So, does training a gym that I'm a member of help defend it?


What is the difference between moment generating function and probability generating function?

I am confused between the two terms " probability generating function" and "moment generating function." How do those terms differ?


How to create/update Global Value Set in apex?

Is there a way to Insert/Upsert a Global value set in apex?


Let's suppose I have a base class B: struct B {     virtual void f(); };  and a class derived from B called D: struct D : B {     void f() override; };  Is there anyway to call B::f from within D::f ? void D::f() {    call B's implementation of f  // <-- ???    do other stuff }


Linux's command line behaviour (Ubunto/Deb) in running an executable file

@user-123:~$ Downloads/execfile-3.4/execfile @user-123:~$  @user-123:~$ cd Downloads/execfileparentdir-3.4/ @user-123:~/Downloads/execfileparentdir-3.4$ execfile execfile: command not found @user-123:~/Downloads/execfileparentdir-3.4$ ./execfile @user-123:~/Downloads/execfileparentdir-3.4$    What's exactly the reason of using ./ behind execfile?   Note that I'm not asking about the functionality of ./. In other words, I wanted to know why in order to run an executable file from terminal it requires the address from current directory to the given file? Why when we are in current directory like the way that the terminal behaves in other cases behave and just recognize the file name automatically so that we run it by just typing the file name instead of putting and ./ behind it?  Edit:  One reason might be the security and preventing the user to accidentally execute another (probably malicious) file. That however is a very credible reason to do so but aren't they sacrificing the consistency of a rule for the sake it? And aren't other ways to handle this problem and not make an exception in a unified rule (the prediction of the file names in current dir)? This may sound like a trivial exchange but I want to be sure if it's the tiniest one.


How to keep track on network usage for long time in system monitor

When I get connected to internet then I open system monitor to track the speed and total uploads and downloads. When I get disconnected and then connected to the network then in system monitor the total uploads and downloads is started from 0. Is there any way by which I can make it continue it to run and according to my need I can refresh it any time I need.    Kidly help me. If what I need cannot be accomplised by system monitor then if possible then provide an alternative option. Thanks.


How to proceed after the below step. Also is there a simpler way to solve this integral?


Im Kinda A Noob With PHP, I want to keep my page accessible only from a link etc. I only want to allow people who clicked a link to my page from example.com and others like from google.com to redirect to another page on my site etc. a error message How Could I Do This?


So I am doing a College research project for my Computer Information Systems department and it is about alternative Linux server distribution for small businesses. From my findings I would really like for this research to actually take off into a Distribution project (Using Ubuntu as a base OS).   However I would like to rename the distribution as "Bizbuntu" or something related to that ("Biz" being shorthand for business) however I don't know if I can name the distribution without consent from Canonical.   So my question is do I have to contact Canonical about this, if so, does anyone know a mailing list or email that I can contact them about this?


I can't find any documentation on upgrading 16.04 to 16.04.1.  I'm assuming having all the package updates does it, but Details is still reporting 16.04 and there is still a 'developer options' tab in Software & Updates, implying I'm still in some experimental release.