Searching and downloading OpenStreetMap data in QGIS

My OpenLayers plugin is under web and not under the plugin and I can't find add OpenStreetMap  layer. I went ahead and opened web > open layers plugin > openstreetmap but this is the error I keep getting.     2018-04-10T13:40:26   1   Traceback (most recent call last): File   "C:/Users/RUKEVWE/.qgis2/python/plugins\openlayers_plugin\weblayers\weblayer.py",   line 100, in addLayer self._addLayerCallback(self) File   "C:/Users/RUKEVWE/.qgis2/python/plugins\openlayers_plugin\openlayers_plugin.py",   line 182, in addLayer self.setMapCrs(coordRefSys) File   "C:/Users/RUKEVWE/.qgis2/python/plugins\openlayers_plugin\openlayers_plugin.py",   line 231, in setMapCrs extMap = coordTrans.transform(extMap,   QgsCoordinateTransform.ForwardTransform) QgsCsException: forward   transform of (-8.208501, -2.390302) PROJ.4: +proj=longlat +datum=WGS84   +no_defs +ellps=WGS84 +towgs84=0,0,0 +to +proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +no_defs Error: latitude or longitude exceeded limits


Copying a file only when it is newer than the destination

How do I copy a file in Linux only when the file being copied is newer than the version at the destination?  If the file at the destination  is newer, I want the file copy to not go ahead.


What is IEEE 802.3 Ethernet's communication type: Synchronous or Asynchronous?

In the IEEE 802.3 frame structure there is a 7 byte preamble section for synchronization. If it is really for synchronization does that mean Ethernet is synchronous and not asynchronous?    Ethernet structure for reference:


I know that here was a few questions about it, but they didn't answer my question. Here is my issue.  I have a mailserver on my dedicated server with full access. In robots I wrote down these lines of code:  mail.domain.com          IN A       11.22.333.444 444.333.22.11.in-addr.arpa       IN PTR     mail.domain.com.   But for  dig -x 11.22.333.444 it returns:  ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 9910 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 3, ADDITIONAL: 0  ;; QUESTION SECTION: ;444.333.22.11.in-addr.arpa.    IN      PTR  ;; ANSWER SECTION: 444.333.22.11.in-addr.arpa. 86400 IN    PTR     444.333.22.11.in-addr.arpa.  ;; AUTHORITY SECTION: 333.22.11.in-addr.arpa. 18516   IN      NS      ns.second-ns.com. 333.22.11.in-addr.arpa. 18516   IN      NS      ns3.second-ns.de. 333.22.11.in-addr.arpa. 18516   IN      NS      ns1.your-server.de.  ;; Query time: 4 msec ;; SERVER: 213.133.100.100#53(213.133.100.100) ;; WHEN: Tue Jan 19 09:30:35 2016 ;; MSG SIZE  rcvd: 148   I was applying the rules which were written in , but still cannot setup rdns.  Any help would be much appreciated.


install Ubuntu 12.04 system requirements

My computer's information:    Processor Intel Pentium 4 3.00ghz (2CPU)    2046MB RAM   Can I install Ubuntu 12.04? Or will it be slow ?


DOS commands for Epson dot matrix not working

Our Epson dot matrix printer is not printing on the following DOS command.:  Type text.txt>prn   But it does print perfectly on:  open TEXT.txt>File>Print    What is the issue here?


$ABCD$ is a square and $AEB$ is an equilateral triangle. Find $\angle DEC$.

I found this question in an exam question paper.  But I was stumped by it. It seemed that all the answers were correct.  I tried:    Let $\angle ADE=x$ and $\angle EDC=y$.  $\angle DAB=90^{\circ}=\angle DAE+\angle EAB=30^{\circ}+60^{\circ}$. $\text{ref}\angle AEB=300^{\circ}$. And we know that $x+y=90^{\circ}$  But now I am stuck. How to proceed?


Using the LRT statistic to test $H_0$ vs $H_1$

Let ${Y_1,...,Y_n}$ be independent random variables and $Y_i$~$N(\beta x_i, 1)$ where $x_1,...,x_n$ are fixed known constants, and $\beta$ is an unknown parameter.  I'm looking to find the p-value or rejection region for  the test  $$H_0: \beta=0 \quad \text{vs} \quad H_1:\beta\ne0$$  The Likelihood Ratio Test statistic $\Lambda$ is  $$e^{-1/2\left(\frac{\sum_{i=1}^n y_i x_i}{\sum_{i=1}^n x_i^2}\right)^2\sum_{i=1}^n x_i^2}$$  I have already asked a similar question with $H_1: \beta>0$ here: .   After setting $\Lambda < k$ I'm left with $\sum x_iy_i$ after removing constants to the right, which is the same as my previous question. How will finding the p-value or rejection region for this test differ?


How do I derive a reduction formula for $\int \frac{x^n}{\sqrt{x^2 + a^2}}dx$?

How do I evaluate a reduction formula for the indefinite integral of $\int \frac{x^n}{\sqrt{x^2 + a^2}}dx$ , for any positive integer n?  I have tried integration by parts, with $u=x^2$ and $\frac{dv}{dx}$ = $\frac{1}{a\sqrt{\frac{x^2}{a^2}+1}}$ but still unable to see any recurring pattern.  Can someone please guide me/show me a sample solution?


Remote desktop without a physical screen plugged in

I set up an old computer on desktop Ubuntu with the goal of having it as a NAS, media server, and torrent machine. After quite a long time and tries with FreeNAS, and Ubuntu server, I finally tried a normal desktop distro and got it working near perfectly. However, now that I've unplugged the screen, when I connect via vnc, the desktop is completely black (and no, it isn't a problem with the power saving settings). Is there any way to force the screen to act as though there's a physical screen or otherwise get it to work?


I installed Ubuntu with Windows. Before installing, I shrunk the space for Ubuntu. Now I have 3.7GB free in my Ubuntu home.That's not enough for me.  So I shrunk my NTFS partition, it's now unalocated. Then I selected ext4 (Ubuntu home) to resize.   But it is 4GB and GParted not allowed to resize more than 4GB. But my 1GB is unallocated.


Can I use blue-green LEDs as MCU state indicators on 3.3 V power?

Modern electronics industry has developed very efficient LEDs with nice and fancy colors (“true green” , “cyan”, and “blue”) based in InGaN technology, or similar. Some of these LEDs are specified as having forward voltages of 3.2 to 4.2 V. Here are examples of such LEDs, , or surface-mount .  But the usual MCUs are powered from 3.3 V supply, and the GPIO output is usually at 3.1-3.2 V, which seems to be barely enough to drive these LEDs . How can I use these LEDs as indicators of some signal statuses, or power rail status? Do I need a series resistor R1 here?    If yes, how do I choose its value?  DISCLAIMER: This "question-answer" comes as elaboration of the original question , to address the particular use case of LEDs as logic state indicators.


Is there a task manager for Windows 7 that shows HDD activity in percent for every process (like in Windows 8)?

I'm looking for a task manager for Windows 7 that shows which process is currently reading/writing on my HDD. I like how the Windows 8 and Windows 10 task manager shows the HDD activity in percent for every process. Is there a custom task manager for Windows 7 that is also has this functionality?  Thanks in advance!


How do I properly make a symlink for /var/www/html while keeping both security and function in mind

I am engaged in a self guided learning project (not school) to simulate a web development environment. Here is system information:  LAMP  server running in VMWare WorkStation Player on Windows 7 host   Ubuntu 16.04 Apache server 2.4.18 MySQL 5.7 PHP 7.0.22 fstp via Filezilla   When transferring files from Windows, I cannot transfer directly to the document root (/var/www/html). For organization reasons I have created sub-directories and files under the html directory. I must use an intermediate folder, which I call transfers, and then copy the file via the terminal. Because I am in a learning process, I wish to employ both best practices and efficiency.  Can I set appropriate permissions in the target directory and then create a symlink, or will permissions in the target directory's parent directories negate using this mind set? Any how/why explanations will be greatly appreciated.


Edit options for shapes in Photoshop (cant seem to edit after creation)

When i first create a shape in Photoshop i get lots of options for fill / line colour, line weight etc. But if i click of that shape layer, on to another layer, then back to the shape layer, i cant seem to get the same options back. Any ideas where i can access the same options menu when editing a shape ?


C++ compiling on Windows and Linux: ifdef switch

I want to run some c++ code on Linux and Windows.  There are some pieces of code that I want to include only for one operating system and not the other.  Is there a standard #ifdef that once can use?  Something like:    #ifdef LINUX_KEY_WORD     ... // linux code goes here.   #elif WINDOWS_KEY_WORD     ... // windows code goes here.   #else    #error "OS not supported!"   #endif     The question is indeed a duplicate but the answers here are much better, especially the accepted one.


In Landau-Lifshitz Classical mechanics textbook, it is said that there are generally $2s-1$ integrals of motion where $s$ is the number of degrees of freedom. Why is that? I couldn't find anywhere an answer.


Boy: You don't pay me to work for you. Woman: No, because what you do here in the workshop isn't a real job. Boy: It isn't a real job? Woman: No. I'm training you for a real job later. Boy: You're training me? Woman: Yes, I'm training you or teaching you what you need to know later.  Which is correct: 1-what you need to know later. 2- what you'll need to know later. Thank you


Prove: Full Rank and a solution os linear system

I'm studying for my exam of linear algebra.. I want to prove the following corollary:     Given $A \in{R^{n\times n}}$, there is a solution $x$ to $Ax = y$ for all $y$, if and only if $A$   has rank $m$ (full row rank).   I know that the rank of a matrix is the maximum number of columns (rows respectively) that are linearly independent and is defined by:     $\operatorname{Img} (A) = \operatorname{Rg} (A):= y \in{C^m}:y = Ax, x \in{C^n}$   My problem is that I can not find a way to relate the two concepts in order to reach a formal proof. Any help?


How to do logistic regression with unequal groups in the dependent variable?

I try to figure out how a logistic regression is handling data with a 0/1 dependent variable. 95% of the data are ones. The purpose of the model is to estimate the probability to be in one of the groups. Of course there are several explanatory variables included.  Fitting the model leads to unsatisfactory results, since the model will predict for almost every observation that it is in category=1. I tried some very naive weighting, which already improved the model. I simply changed the proportion and reran the fitting process with different weights. The weights changed the proportion in the dependent variable (I have no assumptions about the explanatory variables, so every observation in category=1 gets the same weight) to 50:50, 60:40, 70:30 and 80:20. Trusting some validation measures like AIC, different pseudo R2s and the classification table the model with 50:50 weighting is the best. (The calculations of these measures are mostly based on the log likelihood of the corresponding model. So they will be based on the weighted samples.)  These measures probably won't do the job and maybe are inappropriate to find an optimal weighting procedure. My literature somehow skips this point, although I don't think that very unequal groups in the dependent variable are such an uncommon situation. I heard from a colleague of mine, that I should use an ROC curve to find optimal weights.   Can anybody refer to a book ore solution for this problem?   Or can give hints how to handle it?


Trying to track YA novel - virtual reality simulation aboard an interstellar generation ship

I'm trying to track down the title/author of a novel I read some time back.  I read the novel sometime between 1998 and 2004; not sure when it was printed.  The novel itself I originally found in the YA section at my local library.  The setting of the novel is an interstellar generation ship outbound from earth, several generations into the journey.  The plot loosely runs something like this - Several students undergoing what should have been ordinary virtual reality training at school suddenly instead find themselves inside a completely unfamiliar scenario (one which resembles the stereotypical 'you all meet in a bar' RPG intro).  As time goes on, not only are the students drawn back into the 'game' simulation, but they actually begin to disappear from the ship itself - they discover that, in order for everything to go back to normal, they have to win the game.  The whole thing was revealed, in the end, to be the result of a set of embedded programs in the ship's master computer, if I recall correctly, with the programs having been placed there by a programmer who realized that the inhabitants of the ship were effectively breeding the spark of creativity and imagination out of themselves.  Said programmer had taken it on herself to leave them a legacy that would ensure that, by the time they got where they were going, that all-important spark wouldn't have died completely away.  Any suggestions?


Quantify Difference/Distance between Lognormal distributions

I am trying to determine a metric that quantifies the distance between two continuous lognormal distributions. The data is actually a mixture of two lognormal distributions (I am not sure if this can be called bimodal). The individual distributions have different means but the same standard deviations. I have 20 data sets that can be divided into 4 groups, with each group having a constant standard deviation, but the 5 data sets in each group are made up of two distributions with different means. Some examples:      I am in search of a metric that accounts for the contrast (difference in means) and the standard deviation. I have tried out some parameters like coefficient of variation (of the mixture), Ashman's D etc. I have also tried percentage of overlap. However the problem always is that, at the end when plotted against the results I end up with 4 trend-lines again, corresponding to the 4 different standard deviations. Is there some other way I can quantify this?  Just to make myself clear, I want to quantify the difference between two distributions in a single case (between the red and green PDFs in the above image).


How to show that the limit of this sequence exists?

We define $a_1=1$ and $a_{n+1}=\dfrac 12\left(a_n+\dfrac{2}{a_n}\right)$.  I'd like to show that this sequence converges (and $a_n\to\sqrt{2}$). So, I wanted to prove that $a_n$ is monotonic and bounded. I thought that $a_n<\sqrt{2}$, but I was wrong. Maybe this sequence isn't even monotonic.  What do you think?  I already know that if the limit exists, say $l$, then $l=\dfrac{1}{2}\left(l+\dfrac{2}{l}\right)$. But we still need to prove that $a_n$ converges.  Thanks.


Iceland Transit Visa for Canadian Residence ( Indian Passport Holder)

I am an Indian Citizen and Canadian PR holder. Want to book the flight from YYZ ( wow airline) have a route through Iceland (6.55 hours hold) to New-Delhi. Do I require Iceland Visa or Transit Visa?   My outward flight is:     Fri, Jan 11, 2019 Toronto (YYZ) 06:00PM New Delhi (DEL) 03:15 AM + 2   day      Flight 1: | 5h 45m | WW214 | Operated by: WOW air Layover: 6h 55m   | Reykjavik (KEF)      Flight 2: | 10h 5m | WW322 | Operated by: WOW air   And return flight is:     Wed, Jan 30, 2019 New Delhi (DEL) 07:00 AMToronto (YYZ) 05:00 PM      Flight 1: | 11h 50m | WW323 | Operated by: WOW air Layover: 2h 10m |   Reykjavik (KEF)      Flight 2: | 6h 30m | WW213 | Operated by: WOW air


How to remove the default eclipse and setup new eclipse?

I have a eclipse. I removed default eclipse from /usr/lib as,  sudo apt-get remove eclipse   Then I copied my eclipse folder to /usr/lib and tried to launch it as,  sudo eclipse   But I am getting the following error,  usr/bin/eclipse: 35: exec: /usr/lib/eclipse/eclipse: not found   My eclipse which I copied is present in /usr/lib. Why am I getting this error? My requirement is I have to remove the default eclipse and launch my own eclipse from /usr/lib.


In a computer network there are two types of nodes: client and server. Each client is directly connected (using network cables) to at least one server and there are no direct connections between clients. Suppose that each server can route messages to other servers with which it is directly connected and the entire network is connected(the set of servers is connected). In order to make the network more reliable, one scenario is considered:  Every client is directly connected to at least 2 servers and every pair of servers having the distance between them 2 are connected using a direct cable. Prove that, in this new network, if a server becomes unavailable the clients can still communicate with all the remaining servers.  I realised that there are at least two paths which connect a client with a server, but I don't know how to prove that if a server becomes unavailable the clients can still communicate with all the remaining servers.


What configuration would limit my DSLR's shutter speed to 1/200?

I'm using a T4i with a 100mm f/2.8L (with macro twin flash). In manual mode, I could select any shutter speed down to 1/4000. However, when shooting the DSLR would set it back to 1/200. Does it depend on some configuration parameters I did not check/uncheck or upon the flash speed? I'm sure I remember shooting at higher shutter speeds, perhaps with other lenses, if I'm not mistaken.


Why is friction proportional to normal force?

Surely, if you have 2 surfaces interlocking then a horizontal force would also result affect the force of friction. It seems unintuitive that friction is only proportional to normal force.  Is there an intuitive proof of $F=\mu N$?


How to get Line Numbers on execution of C++

Is there an option to provide line numbers on output from the C++ Execution to trace the errors? Sid Kraft


How to install Ubuntu on Nokia C5-00 mobile? Provide a step by step process of installation on Nokia system symbian mobile.


Find the uniform lower bound of the smallest eigenvalue of a certain matrix

I am handling a problem of finding a unifom lower bound ( away from zero ) of  the smallest eigenvalue of  the following real symmetric matrix  $$A =\begin{pmatrix} n & n-1 & n-2 & \cdots & 1\\ n-1 & n-1 & n-2 & \cdots & 1 \\ n-2 & n-2 & n-2 & \cdots & 1 \\ \vdots & \ddots & \ddots & \ddots & \vdots \\ 1 & 1 & \cdots & \cdots & 1 \end{pmatrix}$$  I did some simulation (simulate n from 2 to 1500 ), it shows that the smallest eigenvalue of this matrix may have a lower bound around 0.25. So I try to prove it.   First, I found there may have some results related to the problem. Such as    So I try to use   $$ \lambda_{min} \gt \sqrt{\frac{||A||_F^2-n||A||_E^2}{n(1-||A||_E^2/|det(A)|^{2/n})}} $$  or the result ( Theorem 1 ) in . But only get a trivial lower bound zero.  Then I try to use  to solve the following equivalent problem  $$\inf_{x\in \mathbb{R}^n,~\|x\|_2 = 1} x^{\top} A x$$  By some calculate, I think this problem is the following optimization  $$ \min_{x_i \in \mathbb{R}} x_1^2 + (x_1+x_2)^2 + \cdots (\sum_{i=1}^n x_i)^2~~s.t. ~~\sum_{i=1}^n x_i^2 = 1 $$  or at least find a lower bound of the object function. I tried the method of Lagrange multipliers, and the trigonometric functions to reformular the problem. But I got stuck because of the complicated calculation.   So, I wonder is there anyone may have some ideas about the problem?  Thanks!


A single word for talking about a subject at great lengths?

I'm trying to remember a single-word that I Google'd yesterday (because I didn't know what it meant) which is a word for "Talking about a subject at great lengths", that's almost the exact definition that I still remember, but I can't find the word anymore. I remember that it may be used academically as well because there were some tutorials that I saw about "How to X" (X being the word).


I'm having a problem with my ram on windows 7. The ram is clearing or programs are using and dumping it faster than it can clear. I have 8gb of ram I'm only using 4gb and the rest is in Standby. At best time I can get 100mb of free but its mostly at 15mb or less. I suspect a memory leak but I have no way to figure out what program it is. I have not installed any new hardware recently and newly installed programs have bin closed. Does any one have an idea of what is going on and how to fix it?   I'm sorry this is so little information but that is all I have as well.  Edit: I tried RamMap and found out the my "Mapped File" has 3,291,784k ram in standby how do I figure out what program and how do I limit it's ability to set ram in standby?  Edit: I keep getting a problem when I will have 0 free ram and my computer will stop working properly. It will become outrageously slow where it will take 3-4 minutes to start task manager so I can close some programmes. When I free up some ram by closing some programmes every thing runs normally. It does not matter which programs I closes only that I free up some ram. I know a lot of you say it's supposed to be like that and that's how windows works. But its obviously a problem and my computer has never worked that way neither has any of my other computers. I would like to fix this please help me.


We're having a discussion at work, because of my tendency to name functions based on what they do.  For instance:  function notifyUserOfSomeThingThatHappened(){     // notification code }   My coworker believes (and I kind of agree) that this function should be named based on why it's being called, rather than what it does, since what it does could change.  Something like this:  function someThingHappened(){     // notification code     // possible new code in the future }   I agree with this, but with a catch: I think we should name functions that will only ever do one thing by their actual contents, but other functions by their reason for being called, like this:  function someThingHappened(){     notifyUserThatSomeThingHappened();     // possible new code in the future }  function notifyUserThatSomeThingHappened(){     // original code }   What are the best practices for naming functions? Why are these practices used? What are the advantages of one over the other?


Abiword opens a blank template on startup after upgrade

A quick and annoying problem has come my way.  After I upgraded my Ubuntu from 14.10 to 15.04 I get a blank Abiword template/Abi document opened on login.  This open Abiword doc also applies to my other id's as well on my box when logged into.  Any idea how to stop this from happening?  I have verified that Abiword is not in my start-up list.  Thanks Cheers


R - is it ok to treat autocorrelation by randomly changing the order of variable

I'm working on a multivariate linear regression. I performed a Durbin-Watson test to test for auto-correlation and found it in my model (p-value <0.05 of Durbin Watson test). I then randomly changed the order of the row of the dataframe with the following R-command: df=df[sample(1:nrow(df))]. I re-ran the auto-correlation test and found p-value of around 0.5. It sounds too easy to be true but did I remove the auto-correlation? If not: 1. why? and 2. how should I proceed?  Thank you very much in advance!


Clear working of $\sin(\arccos(-\frac13))$

Can someone show this please. I always had trouble with this in A Level.   It is strange that this expression as an exact value because there is no exact value of $\arccos(-\frac13)$.


How to view all notifications in Chrome?

Sometimes, I miss a chrome notification. I want to see all notifications in some window or panel. Is this possible?


How do I make multiple directories at once in a directory?

I know with mkdir I can do mkdir A B C D E F to create each directory.  How do I create directories A-Z or 1-100 with out typing in each letter or number?


“He said, X” vs. “X, he said” vs. “X, said he”

I’ve long wondered how in reported speech, what sort of change in nuance is produced by switching around the normal order of the subject (that is, the speaker) and the “speech-related” verb (such as , ask, or mutter) used for simple declaration of whatever was said.    Assuming that QQQ below stands for any quoted speech, what — if any — subtle shifts of meaning are there between the following three formats?          He said, “QQQ.”     “QQQ,” he said.     “QQQ,” said he.      In particular, in what situations is the “inverted” VS1  order of said he preferred over either or both of the two versions that use he said in the “normal” SV2  order?  Are these nothing more than three equal options that vary by individual writers’ personal tastes?   If not, then what  rules exist for choosing between and distinguishing these three variants?     1.  VS means verb–subject, or with object, VSO or OVS. 2.  SV means subject–verb, or with object, SVO or OSV.


How to call ajax on "newly created link click" after html dom is ready

After fully loaded the HTML DOM I am calling ajax on form submit and the result I got is: here  Now, again I want to call ajax on that link click: $("#resend_email").on("click", function (e) {     e.preventDefault();     alert(1);     var user_login = $("#user_login").val();     console.log( user_login ); });  But it's not working, I mean at least not showing me the alert. Do you know why, how can I solve it?


Could local ISP capture my location whenever i launch a VPN to a VPN server?

I am extremely concerned that my ISP collects any information once I am connected to a VPN server. For instance, as far as I know, when I start a connection to a HotSpotShield VPN server, an IP address is assigned to me just before a successful connection. Besides, I'll be having an extra IP address at the beginning with the TAP Adapter. An encryption tunnel is set up between me and the VPN server. Whenever my request for a website reaches them (VPN server), they decrypt the data and later they encrypt the reply which returns from the  web (targeted) server. This works like that. So, the ISP can not see what I am watching, displaying and writing because the connection is encrypted. But, the targeted websites see and record all actions. Still, they can not identify my real IP address.   I'm really concerned about if the ISP can see "my location". OK, it has an IP address from another country as my real IP address, but how does my ISP detect the traffic going through them? Can they find out who I am?  Won't they say "Hey, there is a traffic but who is and what he is doing right now?", because I get the Internet from them?


"Closure (deleted)" in profile's Votes Cast is inaccurate if the the close vote was cast after the deleted question was later undeleted and reopened

I voted to close a question on March 31st, 2013.  This question had previously been deleted on March 15th, 2012 then undeleted on March 16th 2012.  In the "Votes Cast" tab of my profile, the closure vote is annotated with "(deleted)", even though the question is not currently deleted, and the undeletion happened long before my close vote.        The "(deleted)" annotation should only be displayed if the post was deleted after the close vote.


Uniqueness of integers satisfying the Extended Euclidian algorithm

I would like to examine whether the following claim is true:  For the following equation: \begin{equation} ax+by=\text{gcd}(a,b) \end{equation}  where $a,b, \in \mathbb{N}$ and $x,y \in \mathbb{Z}$, there exist $x_1,y_1 \in \mathbb{Z}$ such that $x_1 \neq x, y_1 \neq y$ and  \begin{equation} ax_1+by_1=\text{gcd}(a,b) \end{equation} I believe it holds and that it is also possible to express analytically $x_1, y_1$ in terms of $x,y$. I have reached the following point: \begin{align} ax+by=\text{gcd}(a,b) & \Leftrightarrow ax+ax_1-ax_1+by+by_1-by_1=\text{gcd}(a,b) \Leftrightarrow \\ & a(x-x_1)+b(y-y_1)+(ax_1+by_1)=\text{gcd}(a,b) \Leftrightarrow \\ & a(x-x_1)+b(y-y_1)=0 \end{align} where I used the fact that $(ax_1+by_1)=\text{gcd}(a,b)$. After distinguishing cases I end up with $x>x_1, y<y_1$ (or $x<x_1, y>y_1$) and: \begin{equation} x= -(b/a)(y-y_1)+x_1 \end{equation} But from that point on, I cannot figure out how to continue, since when I try to substitute for $y=(\text{gcd}(a,b)-ax)/b$, I end up with just the relation $ax_1+by_1=\text{gcd}(a,b)$.  There must be some wrong step in my proof but I cannot figure it out.


How can I properly fix the vertical alignment of the tombstone (QED sign) in list-proofs?

I frequently encounter the following situation: I am proving a claim which consists of multiple sub-claims, which I've enumerated in a list using the enumerate environment provided by the eponymous package. The proof then also takes the form of such a list. At the end of the proof, the tombstone (a.k.a. QED symbol) appears vertically offset from the final line of the last item of this list. Here's a minimal working example to see this behavior: \documentclass{article}  \usepackage{enumerate} \usepackage{amsthm}  \begin{document}   \begin{proof} \begin{enumerate} \item Problem \end{enumerate} \end{proof}  \end{document  I don't like this behavior, and would like the tombstone to appear vertically aligned with the final line of the last item. So far, I've gotten by with some quick and dirty solutions (using negative \vspace) but I've now come across a case where that doesn't work (because of page breaking). So I'm looking for a proper solution. I've taken a look at , which the site's algorithm suggested to me while typing this up, but didn't like the quick and dirty way suggested there (and wasn't able to implement egreg's answer in a satisfactory manner).


When I try to install Ubuntu, I am unable to view the installation menu. The only thing I can see is a black screen. Are there other methods to install Ubuntu 13.10, & is this a graphic problem?


I have a large file: (file1.csv)  id,code,N 10214411,008.8,1 10214411,038.9,1 10214411,04.81,1 10214411,07.22,1   want to select and generate a new file based on second column with a list of IDs e.g:  second file has a large list of IDs for second column such as:(file2.csv):  0.008.8 07.22   result:(file3.csv)  id,code,N 10214411,008.8,1 10214411,07.22,1


How can I average point features spatially in QGIS?

I have a GPX file with track points and I want to average the points spatially to improve accuracy of the point feature.  I can't just make a polygon and find its centroid as the number of overlapping points in a certain location should "weight" the result more than another location with few points.  ie. if the field data collector was standing in one spot for 2 minutes I should have the bulk of points 'drifting' around the likely location of the point, and have scattered outliers around that, by averaging spatially based on all the points the outliers would be discounted in favour of the clustered points in the averaging.  Do I have to make a raster grid with small resolution and overlay it on my points and then count the points in each cell, or is there an easier geoprocessing kind of function to simply tell me the center coordinates (or make a new point) for the average center?


What is the reason that the value "47" is so popular in electrical engineering?

We often see component values of 4.7K Ohm, 470uF, or 0.47uH.  For example, digikey has millions of 4.7uF ceramic capacitors, and not a single 4.8uF or 4.6uF and only 1 listed for 4.5uF (specialty product).  What's so special about the value 4.7 that sets so far apart from say 4.6 or 4.8 or even 4.4 since in the 3.. series we usually 3.3,33, etc.  How did these numbers come to be so entrenched?  Perhaps a historical reason?


I had windows 7 installed, I had installed linux mint. I freed up one of my partitions from windows drive management to remove linux and now when I load, the screen I get is error: filesystem not found. grub rescue prompt.  What can I do to fix it?


Proving Incertitude Heisenberg principle inequality

let $f\in L^2({\mathbb{R}})$ in ,I want to prove the following inequality  which it is Incertitude Heisenberg principle $$\dfrac{1}{4}\le  \int_{\mathbb{R}} |x f|^2dx \int_{\mathbb{R}} |\xi \hat{f}|^2 d\xi^2$$ satisfies :$\int_{\mathbb{R}} |f(t)|^2dt=1$. Attempt: Let $u = \frac{1}{\| f \|^2_{L^2}} \int_{-\infty}^{+\infty} t |f(t)|^2 dt $ and $v = \frac{1}{2 \pi \| f \|^2} \int _{-\infty}^{+\infty} w |\hat{f}(w)|^2 dw $ which are present middle position and quantum momentum respectively , then: $\sigma_t^2 =  \frac{1}{\| f \|^2}  \int_{-\infty}^{+\infty} (t-u)^2 |f(t)|^2 dt $ and $\sigma_w^2 = \frac{1}{2 \pi \| f \|^2} \int _{-\infty}^{+\infty} (w-v)^2 |\hat{f}(w)|^2 dw $, Then I want the inegality of the product : $\sigma_w^2\sigma_t^2 \geq \frac14$ using integration by part but i can't realise that after substitution.Any Help ? and how I can establish this inegality in $\mathbb{R^n}$ ?


How to install offline packages on a linux server

I need to install offline packages for a linux server. it is a repellent task because all the time it outputs that the package I want to install needs several other packages.  How can I resolve this problem, please ? Regards


Is it posible to upload file in Lists Attachments in SharePoint in custom way I already tried using REST and JS but I am facing an error and it can't upload if it's posible kindly suggest what way to do, if it's not posible I change the flow of my custom lists.      Here is the code I am using.   <input id="getFile" name="file" type="file" multiple />
 <input id="addFileButton" type="button" value="Upload" onclick="upload();"/>


Example of infinite field of characteristic $p\neq 0$

Can you give me an example of infinite field of characteristic $p\neq0$?  Thanks.


How to create block with unapproved comments for dashboard?

I have a question similar to : I'd like to add a block with an overview of unapproved comments on nodes to my dashboard and simply have the possibility to publish them (via a link or button).  How can I do that?


How to create content of content type which is a reference to a paragraph?

I want to add a content to content type (ct1) which has only one field (f1) which is a reference to a paragraph (p1), said paragraph has 4 fields: 3 numeric fields (1, 2, 3) and entity reference (er1) to taxonomy vocabulary, also i am supposed to check if term exists and if term exists then add content, otherwise throw a message and do not add content at all.  I'm Drupal 8 beginner and have no idea where to start with this task. Content creation for non-referenced content types is something I already can do but I do not know how to approach this particular situation. Please link me some guides or post example code.  I do not want to pre-fill paragraphs, it is more like "after-fill" when node is already created and i want to add paragraphs to it. Currently my code looks like this, this is more like pseudo-code, draft:  if (is_file($file) && is_readable($file) && in_array($_FILES['file']['type'], $mimes)) {             $handle = fopen($file, 'r');              $node = Node::create(array(                         'type' => 'your_content_type',                         'title' => date('l jS \of F Y h:i:s A'),                         'langcode' => 'en',                         'uid' => '1',                         'status' => 1,                         'field_fields' => array(),             ));               while (($data = fgetcsv($handle, 1000, $delimiter)) !== FALSE) {  $termExists = taxonomy_term_load_multiple_by_name($field_taxonomy, 'taxonomy');                 if (isset($termExists)) {                     $new_csvLine = Paragraph::create($csvLine);                     $new_csvLine->save();                     $node->paragraph_field_referenced->appendItem($new_csvLine);                 } else {                     return print("Taxonomy term $field_taxonomy doesn't exist, import halted.");                 }             }             $node->save();   I'm working on csv import module and this is the only thing which left to me to complete. Loaded data I need to add as new node of ct1 and each line from csv needs to be a separate paragraph with 4 fields: 1, 2, 3 and er1. Now I need to somehow store this data in these fields. And yes, I need to do this all programmatically, in code. In other words: one csv import is a new node of ct1, every line of csv is new paragraph p1 and every paragraph has to store data from imported line from csv which is 4 fields.  How should I modify saving paragraphs part to make it work the way I described?   One more time about structure of all this:  content type ct1 -> field: f1, type: Entity reference revisions -> paragraph p1 -> fields: numeric 1, 2, 3; er1 type "Entity reference" (reference to taxonomy).


Can I prepay a Credit Card to make a Large Purchase greater than my credit limit?

I want to make a large purchase at a retail store to the sum of $10,000 but the credit limit on my card is set at $2000.  If I send $10K to my credit card will the purchase be allowed to go through?  Not sure if the credit limit is a hard limit or not?  I don't want to be left embarrassed if my card is declined in the store lol.  I called my bank but the answer they gave wasn't too convincing. It was kind of "Errr yes i think its OK!"  Does any one know first hand?


Creating and extracting files from zip archives

Is there a library for crating/extracting zip files in php?  The ZipArchive class works erratically, and this is mentioned on php.net : (for every function I checked)  ZipArchive::addEmptyDir (No version information available, might be only in CVS)


I am just learning blender and am using a tutorial that explains group nodes. It must be made in a previous version since my software is not working the same way. The tutorial explains that when grouping nodes in the node editor, a 'group node' input is created that allows you to connect specific attributes that can then be modified on the group level.  The display I have creates a group but does NOT have any sort of Group node input available that I can see. I understand that the group nodes have been totally redesigned in v2.77 so can anyone point me to information on how to use the group node input feature in this version.  thanks


Why are my Brush options in Illustrator disabled?

I'm trying to make a new calligraphic brush in Illustrator when I noticed alot of the options are disabled can anyone tell me why this is disabled and if it's possible for me to enable them?


I've recently installed Fedora 19.  is installed. But its own examples don't work. When I enter gedti the output is:  bash: gedti: command not found... Similar command is: 'gedit'   And it works correctly but when I enter powertop, the output is:  bash: powertop: command not found...   With no suggestion about the package. Why? Should I edit some configuration files or update some cache or ... ?


How are Vulcans and Romulans different from each other?

I know that Vulcans and Romulan come from the same parent race. But beyond that, how did they branch off? For how long they have been apart? Are they more different than human and chimps? Can they breed?


I want to return the key of the minimum value in a dictionary in Python. The value of key, value pair will have several numbers, i.e. dict[current] = (total, gone, heuristic). How can I return the key of minimum gone value?


How to parse dates to get the year in Python


Cannot select vertices from different object while in edit mode

Whenever I enter edit mode, with 2 separate meshes (cubes), I can only select vertices/edges/faces of 1 mesh.  Example (the screen shot did not include the mouse cursor):    Also, when I enter edit mode with both meshes selected, one of the meshes has a red border and cannot be selected (it also has this border in Object mode):


Installing Windows on a laptop using an external monitor (main display broken)

I have an HP laptop, and I smashed the display, but I work on an external monitor.  I want to reinstall Windows, but the external monitor works only if Windows is installed. What can I do?


What does 'c' stand for in ls -ld on device files?

I was wondering what 'c' stands for in the below command result.   rohith@rohith-pc:~$ ls -ld /dev/null crw-rw-rw- 1 root root 1, 3 Jul  8 06:31 /dev/null rohith@rohith-pc:~$    I could see that this 'c' is present on most of the files in /dev directory. So can I assume that these just mean that the file is a device file?  Thanks in advance! :)


I was just searching for a programming solution via duckduckgo and by clicking one of the top results I ended up on stackoverflowhot.com. This website is an exact copy of Stackoverflow.com and only when I could not upvote an answer, I noticed that it is not the original SO website.  I think this is potentially dangerous. While I did not encounter any atempt to trick me into entering my password or install malware, I assume the intentions of the site owners are not good. Also I guess they are infringing on the copyright of SO and SO users.  So besides from raising awareness of this page, my question is:  Is there any way to report this (besides reporting it as spam on duckduckgo)? Does Stackexchange Inc. have any policy on encountering such clickjacking sites?


What is the difference between "speaking" and "talking"?

It seems more politically correct to say that someone is speaking rather than talking.  What is the definitive difference between these terms?


How do I revert back from sudo add-apt-repository ppa:xorg-edgers/ppa?

I tried to upgrade graphics by running following command:  sudo add-apt-repository ppa:xorg-edgers/ppa  sudo apt-get update sudo apt-get upgrade    However, it caused me a serious problem loading the OS. How do I rollback these changes?


I seem to be getting a more precise version of a double value for certain numbers.   For example, 69.55554, when assigned to a double variable is saved as 69.555539999999993  I have even tried using NSNumber and NSDecimalNumber instead, to no avail. I'm using swift and haven't tested out the same using objective-c.  Any idea on why this occurs and how to fix it (or work around it)? Thanks!  Code Sample where I used NSDecimalNumber  var doubleNumber  : Double  =   69.55554 var decimalNumber           =   NSDecimalNumber(double: doubleNumber)  var label   =   UILabel(frame: CGRectMake(10, 20, 200, 40)) label.text  =   "\(decimalNumber.doubleValue)" self.view.addSubview(label)


After Apple upgrade I'm unable to boot into my ubuntu 13.10 via refit partition

I'm currently running Ubuntu 13.10 on a minimac through a refit partition (500gb mac - 1.5 tb linux). Today I took an apple upgrade to OSX Maverick which was fine and when I tried to boot back into Linux, the refit screen opened, offering me apple or ubuntu. I selected ubuntu and got 'No bootable device -- insert boot disk and press any key. Any help will be appreciated.


I am attempting to install handbrake by using the below commands:  sudo add-apt-repository ppa:stebbins/handbrake-releases  sudo apt-get update sudo apt-get install handbrake-gtk   Which throws an error of:     Reading package lists... Done   Building dependency tree   Reading state information... Done   Some packages could not be installed. This may mean that you have   requested an impossible situation or if you are using the unstable   distribution that some required packages have not yet been created   or been moved out of Incoming.   The following information may help to resolve the situation:      The following packages have unmet dependencies:    handbrake-gtk : Depends: libmp3lame0 (>= 1:3.99.0) but 3.99.5+repack1-7+deb8u1 is to be installed                    Recommends: gstreamer1.0-x but it is not going to be installed   E: Unable to correct problems, you have held broken packages.   So I ran thebelow to see what was held broken packages:  sudo apt-mark showhold   Which returned nothing.  So I then decided to check on both gstreamer and libmp3lame0 and ran  sudo apt-get install libmp3lame0 sudo apt-get install gstreamer0.10-ffmpeg   Which presented a message of * program is already installed.  Then again I tried   sudo apt-get update --fix-missing   And the errors I got were:     Reading package lists... Done   Building dependency tree   Reading state information... Done   Some packages could not be installed. This may mean that you have   requested an impossible situation or if you are using the unstable   distribution that some required packages have not yet been created   or been moved out of Incoming.   The following information may help to resolve the situation:      The following packages have unmet dependencies:    handbrake-gtk : Depends: libmp3lame0 (>= 1:3.99.0) but 3.99.5+repack1-7+deb8u1 is to be installed                    Recommends: gstreamer1.0-x but it is not going to be installed   E: Unable to correct problems, you have held broken packages.   Lastly, I tried using sudo apt-get install -f handbrake-gtk which threw the same error as installing with no -f parameter.  With all that being said, what do I need to do in order to install handbrake?  And my system details are:     DistributerID: BunsenLabs   Description: BunsenLabs GNU/Linux 8.5 (Hydrogen)   Release: 8.5   Codename: Bunsen-Hydrogen   EDIT I am looking for a video convertor (i.e. re-encoder to resize and change the container on some cell phone videos)


Use (or non-use) of articles before abstract nouns

I know I have asked a similar question before but this time I have examples taken from COCA and they do puzzle me. I would love to hear explanations from native speakers.  The following (incomplete) sentences taken from COCA show three different ways of article usage before "reduction of something".  (1) $1.5 billion could be used for things like restoration of fish and wildlife, the reduction of mercury pollution and greenhouse gas reduction.   (2) Fasting imposes a reduction of calorie intake, which is particularly significant if the hours of darkness are few  (3) A key goal of the optimization phase is reduction of communication over-head via a range of techniques, including execution of communication in parallel  Can you say "a reduction of mercury pollution" instead of "the reduction of mercury pollution" in (1)? Likewise, can you say "the reduction of calorie intake" instead of "a reduction of calorie intake" in (2)? If you can, what difference in meaning would that make in each case?   My guess is that, in using "a", the speaker (or writer) has in mind some image of what is to be reduced, whereas in using "the", the speaker (or writer) has in mind more of the fact of reduction itself than what is to be reduced, lacking a better description.  Even if my guess is right, (3) still remains to be explained. Is the lack of article before "reduction of communications over-head" a case of ellipsis? If not, why don't you need an article here as in the other two examples? What difference does the absence of an article make in comparison with "the reduction of communication over-head" or "a reduction of (in) communication over-head"? Can you or should you use "a" or "the" in this case?  In addition, there is another issue in (1). There is no article in front of "restoration". Why is there no article here, whereas there is a definite article in front of "reduction"?


I am trying to import WMS from geoserver link to QGIS 2.8.4 & the latest 2.12.1:    QGIS get the request and show the layers of the workspace, and also the get info. My problem is that the layer is not visible in the view.  It works fine with version 2.2:


The car has been adapted for ( disabled - the disabled) drivers

Choose the correct answer Which one is correct word Is it right to say disabled or the disabled


I want the rendered result to be pixelated and more cell-shaded like you would see in a 2D game.


Neural Networks -- How to design for multiple outputs

Given a multilayer perceptron to be used to separate 2 classes. One has 2 design options.  1 -- Use one output node -- where one class is trained to give an output equal to zero, and the other class is trained to give an output of 1 on this node.   2-- Alternatively one could design a network having 2 output nodes; where one class gives an output of 1 on node #1 and zero on node #2, and the second class gives an output of 0 on node #2 and an output of 1 on node #1.   Which of these two options is considered better?  Also, I notice that the sigmoid function approaches zero but does not quite reach zero. Also, the same function approaches 1 but does not quite reach 1. Given this situation, how can one train a network to output a value of 1 or 0? Should one use something like 0.99 and 0.01 (as opposed to 0 and 1?)


Can we give particle with no mass, mass?

Is it possible to take a particle with no mass and give it mass. For example light? Or increase mass?


Boarding a train in the UK at a later calling station, on an advanced purchase (train specific) ticket

This question is not about breaking a train journey in the United Kingdom.  I wanted return tickets from London to Bicester. Thanks to an , I have purchased return tickets from London to Birmingham, calling at Bicester. I am fairly confident that I can use these tickets to disembark at Bicester, and not go all the way to Birmingham. Please correct me if this is not possible. Similarly on the return journey to London, can I board the scheduled train from Bicester instead of Birmingham?


How many elements does $\mathcal{P}(A)$ have?

Let $A$ be a set of size fifteen. Let $\mathcal{P}(A)$ denote the power set of $A$, that is the set of all the subsets of $A$. How many elements does $\mathcal{P}(A)$ contain?   This is the same as being $0$ or $1$, binary sets of size $1\to 14$?  Does this mean the answer is  ${15\choose 0} + {15\choose 1} + {15\choose 2} +\dots +{15\choose 13}+{15\choose 14}+{15\choose 15}$?  Or is there something I am not considering?


How to calculate the date of birth to display in the following format (Yrs, Mths, Days) using SQL

I would appreciate any help to solve this issue. I am building a report and would like to display the date of birth in the following format e.g: 7Yrs, 5Mths, 3Days based on the given date of birth stored in the database. On my query, I noticed that the calculation applied is giving me wrong results. Here is the query: With cte As  (   SELECT DOB FROM myTableName   where ID ='60113012' )  SELECT CAST(DATEDIFF(yy, DOB, getdate()) AS varchar(4)) +' Yrs '+        CAST(DATEDIFF(mm, DATEADD(yy, DATEDIFF(yy, DOB, getdate()), DOB), getdate())  AS varchar(2)) +' Mths '+        CAST(DATEDIFF(dd, DATEADD(mm, DATEDIFF(mm, DATEADD(yy, DATEDIFF(yy, DOB, getdate()), DOB), getdate()),         DATEADD(yy, DATEDIFF(yy, DOB, getdate()), DOB)), getdate()) AS varchar(2)) +' Days' AS result   FROM cte  Result:  The issue is that I'm getting the wrong results. some of the results have * instead of the number indicating the days. Also, some have a negative before the number of days. Examples: DOB                       Results 2015-08-30 00:00:00.000 5 Yrs -1 Mths * Days 2016-09-02 00:00:00.000 4 Yrs -2 Mths 12 Days 2016-03-18 00:00:00.000 4 Yrs 4 Mths -4 Days 2015-03-21 00:00:00.000 5 Yrs 4 Mths -7 Days


What's the difference between "I did eat" and "I ate"?

In short, what is the difference between the following sentences?   I did eat my lunch an hour ago.  I ate my lunch an hour ago.   They both are past tense. Honestly, I'm confused between them.


How do I handle the window close event in Tkinter?

How do I handle the window close event (user clicking the 'X' button) in a Python Tkinter program?


I have 2 groups with 3 observations each.  Group 1: a=1, b=3, and c=2  Group 2: d=0, e=1, and f=0  I would like to understand which group has the higher values, but cannot use a t-test (neither non-parametric nor dependent t-tests can resolve the special dependency I have in my data).   A solution is to now create all possible combinations of observations. In addition to our data order abc-def, we create abd-cef, abe-cdf, abf-cde, etc. We want all possible permutations, but we don't count within group order differences (abc-def is not different from abc-edf and should be considered one permutation, because the same items belong to the same group).  We create a distribution of group differences across all permutations, and can find out whether our data is within the 2.5% on both ends to see whether the difference is significant on a 5% level.  How would I go about this in R? (I have many more observations but once this example code is setup I could adapt).


Someone left their cell phone here, it was ringing like crazy.  I stuck it in a metal pot with a metal lid to shut it up, it still rang.  I later put it in a safe, it still rang, but so muffled as to not be annoying.  (Admittedly the safe has a gasket on the door--it provides fire, flood and walking out with the guests protection, it wouldn't defeat a serious burglar.)  How is the signal reaching the phone???


I want to migrate some users from my Drupal 7 installation to a new Drupal 8 installation. I do not want to migrate the whole site or any content. And I also do not want to migrate all users.  The problem is the password; I can export from Drupal 7 and import users to Drupal 8, but the passwords do not work anymore. I've also tried to update the hashes (password) in the database directly; so I copied the password fields from Drupal 7 to Drupal 8. That also doesn't work; I think the salt changed in Drupal 8.  Is there any solution for this?


I'm thinking that the singular verbs "is" and "has" are correct below because we're referring to a singular lump of precipitation. Although the subject "inches" is plural, I think the singular verbs are correct below. We wouldn't say, "Fifty dollars are a lot of money." I think this is basically the same concept.  Good for the singular verbs below?  One to 3 inches of snow "is" expected. (Not: ... are expected.)  Ten inches of snow "has" fallen. (Not: ... have fallen.)


Can you prove via induction that there exists a node in a directed graph of n nodes that can be reached in at most two edges from every other node in the graph. Every node in the graph is required to have an edge with every other node that either points out or in (For every pair of nodes X and Y, either X points to Y or Y points to X).


Will ArcGIS Desktop support latest Python 2.x or Python 3.x versions?

I'm curious to know whether ArcGIS Desktop 10.0 will support newer versions of Python than 2.6. And for that matter newer versions of NumPy (ie, 1.4, 1.5 etc). I'm sure that this documentation is on the ESRI site somewhere, but I can't find it.   I have found that ArcGIS Desktop 10.0 will respect an existing Python 2.6 install as long as you have Numpy 1.3.0 installed (), and I'm guessing, at least until Numpy 1.5.0 is out and supporting Python 3, then no Python 3 for ArcGIS, but I'd still be interested to know if upgrading is possible when it's available.


How to create a Book Cover with pdfpages

i know there are many questions on how to create a book cover, but my questions seems to be a bit different.  I create a frontpage, a backpage and the spine for my cover  Frontpage:   \documentclass{scrartcl} \usepackage{geometry} \geometry{   a5paper } \usepackage{blindtext} % \pagestyle{empty} \begin{document}  {\Large Front} \vspace*{4cm}  \blindtext \end{document}   Backpage:  \documentclass{scrartcl} \usepackage{geometry} \geometry{   a5paper } \usepackage{blindtext} % \pagestyle{empty} \begin{document}  {\Large Back} \vspace*{4cm}  \blindtext \end{document}   Spine:  \documentclass[border=0pt]{standalone} % \usepackage{pgfplots} \pgfplotsset{compat=1.9} \usetikzlibrary{patterns} % \begin{document} \begin{tikzpicture}  \node[rotate=90] (a1) at (0,0){Lorem ipsum}; \node[rotate=90] (a1) at (-0.2,10){Etiam lobortis facilisis sem.}; \node[rotate=90] (a1) at (0.2,10){Nullam nec mi et neque pharetra sollicitudin.};  \end{tikzpicture} \end{document}   And putting all together in the cover:  \documentclass{scrartcl} \usepackage{geometry} \geometry{papersize={307mm,210mm}}  \usepackage{pdfpages}  \begin{document} \includepdfmerge[nup=3x1]{back,spine,front} \end{document}   The front and back pages are Din A5, so the cover has the papersice Din A4, which is 297 mm x 210, so i added 10 mm for the spine, which results in 307 mm.  Unfortunately there is to much whitespace added, i played around with some options of includepdfmerge, but i didn't get it work.   Can you help me?  Thanks in advance!


I have written a python code, to solve a puzzle. It was not working as expected. So while debugging I saw something very weird. Row is a list of lists. The append 1 to single row[n] appends to all lists inside row!   def trap( height):         row = []          for index, i in enumerate(height):             if i == 0 and len(row) == 0:                 continue             else:                 if(i > len(row)):#time for a new row                   #to old rows append 0 below                     for j in range(0, len(row)):                         row[j].append(0)                   row = row + [[0]] * (i - len(row))                             else:                   for j in range(0,i):                      row[j].append(0)                   #PROBLEMATIC CODE START                     for jo in range(i,len(row)):                         if(index == 1):                             print("jays are",row)                             print("jo is",jo, row[jo])                         row[jo].append(1)                   #PROBLEMATIC CODE END (I GUESS?)           print(row) #print this, it gives an idea   trap([2,0])   When I try this independently, it works fine, see:  row = [[0],[0]] index = 1  for jo in range(0,len(row)):       if(index == 1):                   print("jays are",row)                   print("jo is",jo, row[jo])                   row[jo].append(1) print(row)    The problematic code has been marked in the python as comment #PROBLEMATIC CODE START and #PROBLEMATIC CODE END. Call the trap() with [2,0]  row variable should be [[0,1],[0,1]] but row variable is coming [[0,1,1],[0,1,1]]  I have been at this for many hours! I just don't understand why does .append() appends to all the lists inside row, but when I try the smaller code it works. Please help me and guide me


How come inside a loop I can create dictionarys of the same, with the ability to manipulate them individually, as opposed to creating them manually?

These codes seem the same on paper but their outcomes show they are different codes under the hood. Is it because of scope within the loop? The output shows on the first example any alteration of the first dictionary changes the second dictionary as well. The second example allows for individual dictionary contents alteration without changing the other dictionary which is also of the same name at creation. new_person = {'haircolor':'blonde'} new_person = {'haircolor':'blonde'}  people = [new_person,new_person]  people[0]['haircolor'] = 'brunette'  print(people)  #######################################  people = []  for num in range(2):     new_person = {'haircolor':'blonde'}     people.append(new_person)  people[0]['haircolor'] = 'brunette'  print(people)


Using an existing telephone system with Skype home service

I'm interested in migrating my current telco-based phone service to a more affordable VOIP solution. Because of this, I've decided to settle on Skype, which I've used for years and has been my choice as my primary desktop VOIP application.  Currently in my home I have a standard phone system that plugs directly into a telephone jack, with 4 wireless handsets. Because I already have this system, I would prefer not to replace it with a different system that's offered for sale in the Skype shop.   My ideal solution would be to purchase an adapter (or some sort of box) that goes between my modem and my existing telephone, to allow my current phone to ring when I receive a Skype call, or allow me to make outgoing calls using my Skype account. Unfortunately, I haven't been able to find anything like this for a home environment, everything that I see is more directed towards office environments.  Does such a product exist, and if so, where can I find out more information about it and/or purchase it?


Is there a term describing a fish's mouth action as it breathes?

I would wager there must be a term of art describing what a fish does as it breathes, normally, underwater. Any thoughts?


Trying to install Ubuntu on Dell XPS 15 (9570)

I have been trying to install Ubuntu on my new laptop:     Dell XPS 15 (9570)   Windows 10 Home 64bit English   8th Generation Intel(R) Core(TM) i7-8750H Processor (9M Cache, up to 4.1 GHz, 6 cores)   16GB, 2x8GB, DDR4, 2666MHz   256GB M.2 2280 PCIe Solid State Drive   NVIDIA(R) GeForce(R) GTX 1050Ti with 4GB GDDR5     I began by trying to install Ubuntu 18.04 LTS using an 8GB USB drive. The first issue I ran into was getting frozen on the bootup screen on the fourth dot. After a couple tries, I plugged in my monitor (through HDMI) and it stopped getting stuck all of a sudden.    Next, I tried to go through the installation and when I clicked on restart now, my computer froze and I had to shut it down manually and start it back up again. At this point I got to the login screen and logged in but after entering my password it got stuck on a purple screen with my mouse pointer (which was frozen). I was able to get into a shell at this point (with ctrl+alt+f4) and attempted to run sudo apt-get install nvidia-390 but this froze when it reached building initial module for 4.15.0-22-generic and upon reboot I had to run sudo dpkg --remove -a.    I was unable to work around this so I attempted to install Ubuntu 16.04 which I could only do by adding acpi=off to the boot configuration (which by the way, I had a lot of trouble getting to since GRUB usually flashed in and then immediately disappeared and only occasionally would it stick around long enough for me to use). But when I try to boot up now, I never reach the screen with the five dots and instead immediately get stuck on a purple screen (with no mouse pointer).  I reinstalled Ubuntu 18.04 and am back to being stuck on the log-in screen.  What should I do?


how to create *.a to *.so in linux user-space?

i done compile file makefile.am and i need shared link for my lib, for example after compile i see /usr/lib64/libtest.a but i need libtest.so because i need my lib to other C source file,   example :g++ -llibtest test.c  i read about this  but i not sure how to work and how to use ranlib or ar,there is any way for create *.a to *.so?


Why doesn't do-release-upgrade offer to upgrade to 17.10 without -d flag?

Why does a simple do-release-upgrade not upgrade from 17.04 to 17.10 if . I have to add the -d flag which treats 17.10 like a development version. It doesn't have any side effects, i.e. the upgrade is performed as expected, but it doesn't seem to be correct and most users might not catch this and complain that the upgrade to 17.10 doesn't work. As far as I remember the same happened when 17.04 was released.  Does do-release-upgrade have an update function I'm missing and which isn't listed in the manpage?


Is there an equivalence relation of which the quotient topology is homeomorphic to codomain of a quotient map?

Let $X,Y$ be topological spaces.  Let $p:X\rightarrow Y$ be a quotient map.  Then, does there exist an equivalence relation $\sim$ on $X$ such that $X/\sim$ is homeomorphic to $Y$?


How to add CheckBox on beginning of ListView

I am working on antivirus program and I am having problems with Quarantine. I added listView as showcase of all viruses that are quarantined, but I need help about some things.  I am having trouble when I put checkbox in separate column, I can still resize that column, And I don't want it to be resizable.  I did this for script. NOTE: Button click is only temporary for adding item  private void button3_Click(object sender, EventArgs e)     {         ListViewItem lvi = new ListViewItem(); // Checkbox          lvi.SubItems.Add(""); // Name of virus         lvi.SubItems.Add(DateTime.Today.ToString()); // Date         lvi.SubItems.Add(); // Location         listView1.Items.Add(lvi);     }   Sorry for duplicated question, I didn't make it clear  Here is image of my idea


How to know if my web site is blocked in China (Great Firewall of China)

I have a new site (with new domain), when I access it from China, it is being blocked. As the domain is a new domain, I am wondering if it is due to the site domain or in fact the IP we used is being banned before.  How to verify and fix?


NT Kernel using a full core in windows 7

I have three identical Windows 7 machines, and the OS is up to date. I just figured out that all three have always a minimum 13% CPU load (1/8 cores) which is due to NT kernel according to the task manager (and not due to a service).  By searching the web I found out that a driver is maybe in cause. I have downloaded the performance monitoring tools from Windows 7 SDK, as well as the UIforETG frontend. I have successfully recorded a trace and visualized it in the SDK GUI. There I can find the "system" process which roughly has 13% of the hits, but I cannot find any information about the drivers.  How can I identify the driver kernel use?


How does the net torque have to be 0 at all points for static equilibrium?

I know that for a mass to be in static equilibrium two things have to be satisfied: $\sum F=0$ and $\sum T=0$, where $T$ represents torque. However, I am not sure how the latter can apply in a situation such as this     Here, a beam is is static equilibrium with only two forces acting on it (let us only consider the y-axis for simplicity's sake), $F_g$ and $F_t$. Clearly the rule of $\sum F=0$ holds and this can be proven with a simple $F_{net}$ statement. However, if the pivot is placed at the very end on the right hand side $\sum T = F_t \sin(55)\cdot0 - F_g\cdot x$, where $x$ is some arbitrary non-zero distance. How can this be if we need $\sum T = 0$?


My attic has a ceiling light controlled by two 3 way switches connected with BX 14/3. Source and light wires were old knob & tube now replaced with Romex 14/2.  The duplex outlet is a new addition. The attached diagram is how I thought it could be wired. The duplex and switch 1 will be in one box. Romex 14/2 from source and light and BX will enter the box.   The diagram shows source connected to duplex. Then a short black wire runs from other duplex hot terminal, wire nutted to BX white wire with black tape, to common on switch 2. Load runs from common on switch 1 to light. I didn’t show ground wires to keep diagram simple, but everything will be grounded. The purpose of this layout was to minimize pigtails & wire nuts. Does this layout meet the NEC?  I posted this again because I couldn't find my original post so thought it didn't get posted. The only difference from the first post was the added sentence stating the purpose of the layout.  Thanks, henrylr


So a while back I built a modern house on a mountain side. After I finished that house I decided to build another house in a different biome. I used creative mode to fly around and find a place to build a new house. Then I didn't play for like half a year. I came back, finished my second house, and wanted to go back to my first house in the mountains, but I totally forgot what direction it was in. I just remember some distinct features about the area. I flew around in creative mode for a while, but I still can't find it :(


Listening to a specific Ajax call from Chrome extension

I am building a Chrome extension that works with a conversion optimization tool (visual website optimizer or VWO to be precise). On websites that use VWO the tool shows information like running experiments, the data needed is retrieved from the DOM.   Now I want to implement a feature that will list goals fired on a page. A goal is a user defined event such as page view, clicks on elements etc. When a goal is fired VWO sends a c.gif call to their server, this call contains the information I need.   I can see the c.gif call in the Chrome network console so I assume my extension should somehow be able to do the same. But how this is achieved I can't figure out. And help here would be greatly appreciated :)   I found some help here:  and here:  but I couldn't get my code to register the Ajax event (or any Ajax event).   My extension is designed like this: A default pop-up.html with a pop-up.js that on load fetches the background script. The background script asks the content script for the DOM data. When the data is retrieved it is send back via the background to the popup.js  I hope someone can help me with this. If possible I would prefer not to use jQuery (or another library) unless they make matters much easier. (that's why I tagged jQuery)


Are the eigenvectors of $A^2$ the same as the eigenvectors for $A$? Are the lambdas just squared?

Given matrix $A$, we square it. We found the eigenvalues and eigenvectors for $A$. If we square $A$ (or it to a power of any number $n$), do the eigenvalues become squares (or to the power of any number $n$), while the eigenvectors remain the same?


Can anyone explain why is this happening?  Case 1:  >>> a = [[0]] *3 >>> print a [[0], [0], [0]] >>> a[1].append(0) >>> print a [[0, 0], [0, 0], [0, 0]]   Case 2:  >>> a = [[0],[0],[0]] >>> print a [[0], [0], [0]] >>> a[1].append(0) >>> print a [[0], [0, 0], [0]]   Why is this going on? I am expecting that the behavior of the array in case 1 to be as in case 2 but it is not for some reason.


SQL Server agent option in SQL Server Express

I am using SQL Server 2008 Express. I don't have SQL Server Agent option in it. How can I enable it?  I have searched on internet, but couldn't find anything. Do I need to install anything?


Editing Gsettings from Cron via script doesn't work

So, I'm trying to change my theme from a light to a dark version in the evening, and vica versa in the morning. However, Gsettings doesn't work from Cron, and the solutions posted  and  don't seem to work, neither do those posted in the comments below them.  This is the script Cron is executing:  #!/bin/bash  #Export DBUS_SESSION_BUS_ADDRESS environment variable PID=$(pgrep -o gnome-shell) export DBUS_SESSION_BUS_ADDRESS=$(grep -z DBUS_SESSION_BUS_ADDRESS/proc/$PID/environ|cut -d= -f2-)  #Change theme gsettings set org.gnome.desktop.interface gtk-theme 'Arc-Dark' gsettings set org.gnome.shell.extensions.user-theme name 'Arc-Dark'   And this is the error I'm getting in dead.letter (Crons' way of logging errors):  grep: /proc/1098/environ: Permission denied  (process:28536): dconf-WARNING **: failed to commit changes to dconf: The given address is empty   grep: /proc/1098/environ: Permission denied  (process:28811): dconf-WARNING **: failed to commit changes to dconf: The given address is empty   I know I can use sudo -u to run the script, but I'd rather not use the root cron.


Some issues about Uniform Distibution in Inverse Transform Method

There is a theorem about inverse transform method says if X is a continuous random variable with cdf F, then U=F(X)~U[0,1]  So I am wondering the logic in this sentence.  Why if X is a continuous random variable with cdf F, then U=F(X)~U[0,1]? Why is it always be uniform and  how does this theorem work in real example?


sed - find and replace text containing "/"

How can I search and replace text that contains / with sed?  I currently use the following command which doesn't work  sed -i "s/queue_directory = /var/spool/postfix-secondary/queue_directory = /var/spool/postfix-$newnumber/g" /etc/postfix-$newnumber/main.cf


Possible typo on "A new hope" hat description

I had earned the  hat but its description states that you can earn this hat posting a question/answer, or voting on December 18th     Ask, answer, or vote on December 18th   I'm at UTC+1 and today is not Dec 18th...Is this a typo or whatelse?


Which MySQL data type to use for storing boolean values

Since MySQL doesn't seem to have any 'boolean' data type, which data type do you 'abuse' for storing true/false information in MySQL?  Especially in the context of writing and reading from/to a PHP script.  Over time I have used and seen several approaches:   tinyint, varchar fields containing the values 0/1, varchar fields containing the strings '0'/'1' or 'true'/'false' and finally enum Fields containing the two options 'true'/'false'.   None of the above seems optimal. I tend to prefer the tinyint 0/1 variant, since automatic type conversion in PHP gives me boolean values rather simply.  So which data type do you use? Is there a type designed for boolean values which I have overlooked? Do you see any advantages/disadvantages by using one type or another?


How to copy the files from remote unix server to local windows?

I have my working system in a remote location and the os is in unix and i need to get the files from that remote unix system to my local machine using bash commands. I tried  scp ls .txt*  D:\BACKUP   this command by connecting using putty to my remote system.  i tried but its not working.


For the plural possessive of a surname, would you concur that these are correct? the Rogerses' house (surname is 'Rogers') or should it be "the Rogers' house" for the plural possessive because 'Rogerses' is awkward? the Hastingses' property (surname is 'Hastings') or should it be "the Hastings' property"for the plural possessive because 'Hastingses' is awkward? Correct to these four?  the Williamses' property line the Kennedys' house the Joneses' dog the Goronskys' pool  And lastly, would the following be a possessive or descriptive? 1 or 2?  (1) the Stevenses' family tree (2) the Stevens family tree  A big and appreciative thanks.


Inequality from Chapter 5 of the book *How to Think Like a Mathematician*

This is from the book How to think like a Mathematician,  How can I prove the inequality $$\sqrt[\large 7]{7!} < \sqrt[\large 8]{8!}$$  without complicated calculus? I tried and finally obtained just $$\frac 17 \cdot \ln(7!) < \frac 18 \cdot \ln(8!)$$


Evaluating $\sum_{n=1}^{\infty}\frac{(n-1)!}{\prod_{r=1}^{n}(x+r)}$ for $x\in\mathbb{R}^{+}$

I am trying to evaluate the following sum. Here $x\in\mathbb{R^{+}}$. $$f(x)=\sum_{n=1}^{\infty}\frac{(n-1)!}{\prod_{r=1}^{n}(x+r)}$$ At present I do not know how to proceed. Any hints are appreciated. Thanks.


do I need to change my disc if the brake pads got oil on them

In trying to change the brake pads on my mountain bike, I managed to get oil on my new pads and empty out all the brake fluid, and consequently also get some oil on the disc. I took the bike to the shop and they are now telling me I need to change the pads and the disc. I can understand the pads, but do I really need to change the disc or is the guy (girl actually) just scamming me. The disc is not soaking in oil, from what I can tell it just has a bit of oil here and there.


Is there a way to check what percentage of your close votes are on closed questions?

Let's say I have cast 100 close votes.  How can I easily determine how many of those close votes are on questions which are currently closed? This would be useful for understanding how well my personal close voting preference matches a site's overall philosophy on when questions should be closed, reopened, etc.  Even more awesome would be:   Close votes on questions which were closed (even if reopened) Close votes on questions which are currently closed Close votes on questions which are deleted


$a\mid b,c\mid d\Rightarrow\,\gcd(a,c)\mid \gcd(b,d)$

So far I have that $a|b$ implies $b=ax$ for some x in the integers and $c|d$ implies that $d=cy$ for some y in the integers.  From here I can see that $gcd(a,c)|gcd(b,d)$ is logically equivalent to $gcd(a,c)|gcd(ax,cy)$ but I am not sure where to go from there.


Apply a cloud mask to a Landsat8 collection in Google Earth Engine - time series

I have tried to apply a cloud mask for a landsat 8 collection using , , and  but none will work.  code1 encounters the error of not working even after changing   var mask = img.select(['cfmask']).neq(4) to   var mask = img.select(['pizel_qa_bands']).neq(3)  code2 encounters the problem of not being a time series dataset. I want to be able to extract pixel values for each image over a period of time but this code only gives one output of pixel values.  and I can't adapt my script to code3.  Here is my script and all i want to do is remove the clouds and cloud cover from a Landsat8 image collection     var l8_mayo = ee.ImageCollection('LANDSAT/LC08/C01/T1_TOA')   .filterDate('2000-01-01', '2018-12-31')   .filter(ee.Filter.eq('WRS_PATH', 208))   .filter(ee.Filter.eq('WRS_ROW', 23));  var visParams = {bands: ['B4', 'B3', 'B2'], max: 0.3}; Map.setCenter(-9, 53, 8); Map.addLayer(l8_mayo, visParams, 'l8_mayo collection');`


How did photographers touch up photographs before the invention of Adobe Photoshop?

Photoshop is very popular for retouch pictures taken by photographers. But how did photographers touch up photographs before the invention of Adobe Photoshop?


Is it possible to restrict a single app on the S6 from connecting to the internet?

Is there a way to stop a particular app from establishing ANY sort of outgoing connections to the internet but I still want the app to be able to use the internet when I want to but still be able to block "unverified  connections at the same time. Such a thing exists?


Carrera Crossfire 2 Hybrid Bike to a road bike

I have a Carrera Crossfire 2 Hybrid Bike. I would like to convert this to a full road bike. Is it possible?, if so what changes will I need to make.


Coriolis problem by conservation of angular momentum

A stone is dropped from a stationary helicopter 500 m above the ground at the equator. How far from the point vertically beneath the helicopter does it land and in what direction? You should solve this problem in two ways: a) by consideration of the angular momentum of the stone; b) by invoking the Coriolis force.  The b) part works out well in just a couple of lines, giving ca 24 cm to the west as an answer (correct). However, I don't seem to be able to get a) right. I tried to consider the stone as rotating around the Earth starting at a distance of R+500 m (R being the radius of the Earth) and then falling downwards with gravity and consequently speeding up in rotation as well, due to the distance to the centre of rotation getting smaller. After some nasty integrals this gave the answer to be 48 cm, about exactly a factor of 2 larger than in part b). However, I also had to use R in the final calculations which was not given in the question, hence this is probably not the way it was meant to be done.  Anybody who knows how part a) is to be attacked? Many thanks. :)


can I use both ubuntu and windows 8 when I download online?

If I download ubuntu on my windows 8 , is it going to completely replace the windows OS in the sense that I cannot use windows 8 anymore on my laptop?


Render node author profile image in node template

I am working on customization Node template file in Drupal 8, I added another field to user in admin/config/people/accounts/fields ( my field is field_bio). Now I want to render author image( with specified image style) and field_bio in node template`.  How can I achieve this?


How do I migrate my existing Apple Notes from iOS 4 into Simplenote, Evernote, or some other notes app?

I have an iPhone with 100+ notes that I've collected over the last ten years (thanks to migrating from my PalmPilot). I realize that I can now synchronise these with Gmail, but that doesn't allow me to edit them from my computer. I'd rather switch to use a new app/website combo which allows for online editing of notes, automatic OTA syncing, etc.  It seems like Simplenote and Evernote are two of the better app/sites, as mentioned at  and from this , I think Simplenote is exactly what I'm looking for. The problem is, I can't figure out how to migrate all of my existing notes into whatever new notes app I choose.  How do I migrate my existing Apple iOS Notes into Simplenote or Evernote?  The best workaround I've found so far is to open each note, select all, copy, and create a new note in the iOS app but I'd rather not spend the time and hassle doing this for ~100 notes.


As I mentioned there , how can I view documents( ex: .doc,.docx and all other formats ) from the command line ? Is there any way ?  Thank you.


Chilean, Canadian national transit through the US during COVID-19

Imagine a dual Chilean-Canadian national who wishes to fly from Chile to Canada in September, 2020. There are currently no flights directly from Chile to Canada (in better times there was an SCL-YYZ route). Can this person safely use a ticket that transits through US airports given restrictions on entry due to COVID-19, assuming they meet the usual entry requirements for a Chilean (e.g., eligible for visa waiver program)?


My paper was retracted – how can I handle this in my future career?

In September 2016 I saw a PhD advertisement in a forum. I emailed the advertiser and he sent me a half-baked draft of a research project and told me that if I want this position I would need a first-author publication and therefore I should make that draft publishable. I did that and sent the draft back to him.  After some time I asked him about the paper and he told he has submitted that and we will hear from the journal soon, but he did not give me any confirmation email from any journal. After few months he asked me to do the same analysis on another topic but this time from the scratch.  I started research on that topic when I was waiting for the journal he mentioned to inform us. One night, in Skype he asked me to send him some of my personal pictures. First I thought he might just be curious but he started a nasty conversation about my marital status etc. I felt that something was going wrong and I told him that I don’t want to carry on that that collaboration. I stopped research on the second topic and ask him about the status of the submitted paper. He replied that he didn’t want to publish that with me anymore.  I was just shocked by his reaction and got too upset feeling being badly abused. I then submitted the draft to a journal in 2017 without mentioning his name, but he asked for retraction. I sent all of conversation via Skype and Teamviewer to the editor and him. The editor told me I should disclose this with his university, but that the journal could not help and has to retract the paper. The paper has been fully retracted in November 2019. The retraction note of the journal says:     This paper is significantly overlapped and based on an unpublished research by ...   The author disagrees with this retraction   Does this retraction note imply that I committed some academic misconduct? How can I handle it in future academic applications.


How to get back to Ubuntu from Chrome OS?

I installed Ubuntu from lifehacker.com, onto my Acer Chromebook, where you access it by switching back and forth between Chrome OS and Ubuntu with ctrl alt shift and ← and →. I shut down my computer and when I turned it on, I was unable to access Ubuntu again.   I need help getting back to it to install some programs that I require.


Calculate mean and standard deviation of a normal distribution given probabilities at three points only

I was looking for a method to calculate mean and standard deviation of a normal distribution where P(X=x) is given at three points that is P(X=10111) = 0.3, P(X=10840) = 0.5, and P(X=10948) = 0.6


I am learning about closures. I found this code online. However, I am not able to make sense of why it is working.  const addTo = x => y => x + y; var addToTen = addTo(10); addToTen(3);   It returns 13. However, I do not understand why though.   Could somebody please explain why that is happening?  Thanks a lot for your time and have a wonderful day :D


int main() {     int c=5;     printf("%d\n%d\n%d", c, c<<=2, c>>=2);     return 0; }   I am not getting how the assignment is taking place in the printf function. The output is coming out to be 4,4,4 but according to me it should be 4,4,1.


Php parse to javascript variable or array

I have this php script  <?php                     include ("db.php");                     $result = mysql_query("SELECT fbuid from fbusers");                     while($array = mysql_fetch_array ($result)){                                                 print("alert ($array[0]);");                                                                    }  ?>   I want to store the returned values in a javascript variable or array so I can check if a fb user it's already registered in my app. Could somebody tell me how could I store the mysql_fetch_array to javascript?


Redirect output from all commands to file, not just last

I want to add a header to a file with echo, then use a command to create the rest of the file. This means I'll be using two separate commands.  How do I write the output from both commands to a file with redirection?  I've tried  echo "header line" | cut -c 1-5 input_file > output_file  echo "header line"; cut -c 1-5 input_file > output_file   This only redirects the output from the cut command.  The following command works, but feels clumsy:  echo "header line" > output_file; cut -c 1-5 input_file >> output_file   What is the clever way of solving my problem?


I'm reading a book about abstract algebra, but I'm having trouble solving this excercise: "Show that $(\mathbb{Q}^*,\cdot)$ and $(\mathbb{R}^*,\cdot)$ aren't cyclic"  Where $(\mathbb{Q}^*,\cdot)$ is the group of nonzero rational numbers under multiplication and $(\mathbb{R}^*,\cdot)$ is the group of nonzero real numbers under multiplication.    Here is my attempt for the first.  Suppose $(\mathbb{Q}^*,\cdot)$ is cyclic, then $\mathbb{Q}^*=\langle\frac{p}{q}\rangle=\{(\frac{p}{q})^n,n\in\mathbb{Z}\}$, where $p$ and $q$ are coprime.  $\frac{2p}{q}$ is also in $\mathbb{Q}^*$ so it must be equal to $(\frac{p}{q})^n$ for some $n\in\mathbb{Z}$.  To solve $\frac{2p}{q}=(\frac{p}{q})^n$, I take a logarithm of both sides and end up with $1+\log_\frac{p}{q}(2)=n$, since $n$ is an integer $\log_\frac{p}{q}(2)$ must be an integer too, but it is possible only when $\frac{p}{q}=2^{\frac{1}{k}}, k\in\mathbb{N}$, (i.e. $\frac{p}{q}$ is a k-th root of $2$), but $k$ must be $1$ for $2^\frac{1}{k}$ to be rational so $\frac{p}{q}=2$ contradicting the hypothesis of $p$ and $q$ being coprime.    However I don't know whether this is a proper proof and the same reasoning cannot be applied to $\mathbb{R}^*$, I'd like you to just give me an hint towards a proof, without telling me the whole proof, if possible.


When my co-founder and I were creating our project (with a scientific background), we always listed our universities as our affiliation, or we listed ourselves as the Co-Founders of the project with an e-mail. For the last two years or so, my co-founder has worked at a technology company in the UK, while I am still on my PhD in the US.  Now, if we author a paper, is it okay to list my university and his work affiliation (the company)? Formally, this would be correct. However, he does not work on our stuff during work hours but only in his freetime and at home.  If we do list the two affiliations (university me, company him), does it imply that the paper has a commercial touch? His employer is okay with it.   Would this setup complicate creating a startup from now on?


Limit of $\frac{\log(n!)}{n\log(n)}$ as $n\to\infty$.

I can't seem to find a good way to solve this.  I tried using L'Hopitals, but the derivative of $\log(n!)$ is really ugly. I know that the answer is 1, but I do not know why the answer is one.  Any simple way to go about this?


Is there an OS which can be used without RAM, specifically the kind I can create a bootable pendrive from and use it in the computer?  This gets awkward, since booting is essentially loading OS in RAM.  Note: I originally wanted to know about a RAM-less OS to check if my laptop (which does not boot but presents a blank screen) RAM had gone bad, but I like the way this question has snowballed.


NullPointerException when using attribute from one class in another

class PointInPlane {     public float x;     public float y;      static class CircleInPlane {         public static float r;           public static float xcentr;         public static float ycentr;          static void solve(PointInPlane a, PointInPlane b, PointInPlane c) {             float A = (b.y-a.y)/(b.x-a.x); //geting NullPointerExeption              float B = (c.y-b.y)/(c.x-b.x); //probably will get in all next steps             xcentr = (A*B*(a.y-c.y)+B*(a.x+b.x)-A*(b.x+c.x))/(2*(B-A));             ycentr = A*(xcentr-a.x)+a.y;             r = sqrt((pow((a.x - xcentr), 2) + pow((a.y - ycentr), 2)));          }     } }   So   IDK how I can handle this problem. I'm getting NullPointerException when declare float A. I think the problem is that I'm using fields from one class in another or trying to use PointInPlane objects a, b and c with null fields. How this problem could be solved?


Why is the Continuum Hypothesis (not) true?

I'm making my way through Thomas W Hungerfords's seminal text "Abstract Algebra 2nd Edition w/ Sets, Logics and Categories" where he makes the statement that the Continuum Hypothesis (There does not exist a set with a cardinality less than the reals and no set strictly greater than the natural numbers.) is neither true or false.  This is utterly baffling to me, If it's possible to construct a set between $\mathbb{N}$ and $\mathbb{R}$ then this statement is demonstrably false, but if not then the statement is true.  This seems to be a straitforward deduction, but many with a more advanced understanding of the topic matter believe CH to be neither.  How can this be?


Show *realtime* mouse cursor coordinates? (Cursor mod / overlay) Also, copy to clipboard?

I'm looking for a solution that would display the current mouse cursor coordinates in realtime (i.e. NOT xdotool and NOT xev).  I need to move the mouse to a certain position, then press Alt-Tab to flip to another window and record the coordinates there. (This would not move the mouse, so the coordinate display would stay the same).  There's a Windows program that works BEAUTIFULLY for this purpose -   ...but it doesn't even start up in Wine.  Alternately, instead of displaying the coordinates, if this solution could copy the coordinates (in XXX,YYY format) to the clipboard, upon pressing a hotkey, that would be even better.  Any suggestions would be much appreciated!  P.S. I'm running Ubuntu 12.04 LTS.


How to sort a list in python based on internal list?

I have a list as follow:  list1 = [['10', 'John', 'python'], ['1', 'Sara', 'java'], ['3','Tom', 'C']]   and as sorted result I expect following outpt:  3 Tom C 1 Sara Java 10 John python   in fact I want to sort it base on second parameter in internal list. This code does not work:  sort1 = sorted(list1, key=lambda x: x[0][1])


Did English ever have a word for 'yes' for negative questions?

The Germans have doch and the French have si as a word that means "yes" in response to a negative question, such as:     Don't you want some ice-cream?   Yes [I do]!   In English, we only have yes (as far as I know) and further clarification is required in order to be unambiguous.  Did we ever have such a word in English and, if so, what happened to it? If not, given the French and Germanic influences on English, any idea why not?


Ubuntu 18.04 fresh installation, Thunderbird inbox "invaded" by large icons (coloured emojis)

From my old HD (Ubuntu 16.04) I copied ~/.thunderbird and other programs to the new disk with Ubuntu 18.04 installed. All went good. I tried to install Opera. The installation was unsuccessful, a window asking something was held. After that Thunderbird Local Folders -> Inbox (only) was invaded by large icons like this screenshot  Flowers, plants, trucks and others. I restarted but those images are still there. Opera was successfully installed. What can I do to remove them?


I am not a native speaker. So please excuse my "silly" question.   I have learned in my school that one can only use the word "where" in contexts describing locations, positions [or directions]. But I have come across two sentences used by a native speaker and I wonder if they are correct.     1) It can fill in details where experimental methods cannot.       2) Computer simulations are accurate on predicting molecular motions   but work poorly where quantum effects are important.   Can someone explain to me why he can use the word "where"? Many thanks!


Are there algorithms for computing "running" linear or logistic regression parameters?

A paper "Accurately computing running variance" at  shows how to compute running mean, variance and standard deviations.  Are there algorithms where the parameters of a linear or logistic regression model can be similarly "dynamically" updated as each new training record is provided?


How do I get a Realtek RTL8723BE wireless card to work?

I have installed Ubuntu 15.04 on my laptop with RTL8723BE Wi-fi card. But it is always disconnecting from network. I have tried echo "options rtl8723be fwlps=N ips=N" | sudo tee /etc/modprobe.d/rtl8723be.conf but that didn't helped. What can I do to prevent the wifi from disconnecting? If I upgrade to kernel 4.X, will it help?  ~$ lspci -knn | grep Net -A2  09:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd. RTL8723BE PCIe Wireless Network Adapter [10ec:b723]     Subsystem: Hewlett-Packard Company Device [103c:2231]     Kernel driver in use: rtl8723be   ~$ rfkill list 0: hci0: Bluetooth     Soft blocked: yes     Hard blocked: no 1: phy0: Wireless LAN     Soft blocked: no     Hard blocked: no   ~$ ifconfig && iwconfig && route -n && ping -c 1 google.com eth0      Link encap:Ethernet  HWaddr 38:63:bb:cd:4a:7e             UP BROADCAST MULTICAST  MTU:1500  Metric:1           RX packets:3 errors:0 dropped:0 overruns:0 frame:0           TX packets:53 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:1000            RX bytes:752 (752.0 B)  TX bytes:8445 (8.4 KB)  lo        Link encap:Local Loopback             inet addr:127.0.0.1  Mask:255.0.0.0           inet6 addr: ::1/128 Scope:Host           UP LOOPBACK RUNNING  MTU:65536  Metric:1           RX packets:3870 errors:0 dropped:0 overruns:0 frame:0           TX packets:3870 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:0            RX bytes:314613 (314.6 KB)  TX bytes:314613 (314.6 KB)  wlan0     Link encap:Ethernet  HWaddr c0:38:96:6d:c4:83             inet addr:192.168.1.205  Bcast:192.168.1.255  Mask:255.255.255.0           inet6 addr: fe80::c238:96ff:fe6d:c483/64 Scope:Link           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1           RX packets:15240 errors:0 dropped:0 overruns:0 frame:0           TX packets:14627 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:1000            RX bytes:14410285 (14.4 MB)  TX bytes:2192744 (2.1 MB)  eth0      no wireless extensions.  wlan0     IEEE 802.11bgn  ESSID:"DIR-615"             Mode:Managed  Frequency:2.437 GHz  Access Point: 00:90:4C:08:00:0D              Bit Rate=150 Mb/s   Tx-Power=20 dBm              Retry short limit:7   RTS thr=2347 B   Fragment thr:off           Power Management:off           Link Quality=70/70  Signal level=-22 dBm             Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0           Tx excessive retries:0  Invalid misc:186   Missed beacon:0  lo        no wireless extensions.  Kernel IP routing table Destination     Gateway         Genmask         Flags Metric Ref    Use Iface 0.0.0.0         192.168.1.1     0.0.0.0         UG    400    0        0 wlan0 169.254.0.0     0.0.0.0         255.255.0.0     U     1000   0        0 wlan0 192.168.1.0     0.0.0.0         255.255.255.0   U     0      0        0 wlan0 PING google.com.Dlink (172.26.136.19) 56(84) bytes of data. 64 bytes from 19.136.26.172.in-addr.arpa (172.26.136.19): icmp_seq=1 ttl=249 time=102 ms  --- google.com.Dlink ping statistics --- 1 packets transmitted, 1 received, 0% packet loss, time 0ms rtt min/avg/max/mdev = 102.547/102.547/102.547/0.000 ms


Can I somehow make a pmatrix play nicely with a tabular environment? I tried using \def\arraystretch{1.5} but it made everything bigger. Here's a minimal example that shows my problem. I'm using XeLaTeX.  \documentclass[12pt,a4paper]{report} \usepackage[english, polish]{babel} \usepackage{graphicx} \usepackage{float} \usepackage{amsmath} \usepackage{amsfonts} \begin{document} \begin{table}[H] \centering \resizebox{\textwidth}{!}{% \begin{tabular}{|c|c|c|} \hline Ciąg do zakodowania & Wykorzystana bramka                                          & Powstały stan kwantowy \\ \hline 00                  & $ \mathbb{I} = \begin{bmatrix} 1 & 0 \\ 0 & 1\end{bmatrix} $ &                        \\ \hline 10                  & $ Z = \begin{bmatrix} 1 & 0 \\ 0 & -1 \end{bmatrix} $        &                        \\ \hline 01                  & $ X = \begin{bmatrix} 0 & 1 \\ 1 & 0 \end{bmatrix}$          &                        \\ \hline 11                  & $ Z*X $                                                      &                        \\ \hline \end{tabular}% } \caption{A little bit too cramped :(} \label{my-label} \end{table} \end{document}


How to move system partition on same hdd?

So I currently have an inconvenient partition config on my win7/ubuntu system. what i wanna do is to have the extended sdb3 moved ajar like in the  to later add a swap and home partition (latter is on another drive).  Despite the easy sounding explanation here  gparted only allows me to put a copy (sdb4) of sdb5 to the desired location. i already tried desperately to make that copy boot-able (UUID in grub) for hours with no progress so far so i am open for any input.


Boolean Union vs Difference Error - Swapped Behaviour

I've been working happily with Blender all this week and last, performing hundreds of operations, many booleans, and getting good results in a rudimentary model for a small enclosure.     Today I've renamed the file to v2, and started to make a couple of changes.  I'm just removing some material using a simple shape to create insets and a boolean difference operation.  Suddenly, though, the 'difference' is behaving like a 'union' and vice-versa.  I thought I'd forgotten something overnight, and tried it on two other simple objects in the same design, with the same result. I then opened a new design with just two cubes and tried it there, where it works without error.  Quit, back to my own design v2, and still the behavior is swapped.     I've restarted Blender a couple of times.  Moving on to trying more renaming, rebooting tests etc.  Is this a known issue, am I missing something obvious? Is there a work-around that someone can suggest.   (I'm using ver 2.70 on Mac OS 10.8.5)


How do I catch a PHP fatal (`E_ERROR`) error?

I can use set_error_handler() to catch most PHP errors, but it doesn't work for fatal (E_ERROR) errors, such as calling a function that doesn't exist. Is there another way to catch these errors?  I am trying to call mail() for all errors and am running PHP 5.2.3.