Prove $\int\limits_{0}^{\infty} \mathrm{exp}(-ax^{2}-\frac{b}{x^{2}}) \mathrm{d} x = \frac{1}{2}\sqrt{\frac{\pi}{a}}\mathrm{e}^{-2\sqrt{ab}}$

This is Example 8.4.1 from Chapter 8 (The Normal Integral) of  by Boros and Moll. The authors outlined a solution method, which I will provide in full here. My question: is there another way to obtain this result?  Here is the solution of Boros and Moll with their notation.  Let \begin{equation} \mathrm{L}(a,b) := \int\limits_{0}^{\infty} \mathrm{exp}(-ax^{2}-\frac{b}{x^{2}}) \mathrm{d} x \label{eq:iic8-1} \tag{1} \end{equation} Making the substitution $t=x\sqrt{a}$ yields \begin{equation} \int\limits_{0}^{\infty} \mathrm{exp}(-ax^{2}-\frac{b}{x^{2}}) \mathrm{d} x = \frac{1}{\sqrt{a}} \int\limits_{0}^{\infty}  \mathrm{exp}(-t^{2}-\frac{ab}{t^{2}}) \mathrm{d} t \label{eq:iic8-2} \tag{2} \end{equation} Letting $ab=c$ we call the integral in equation \eqref{eq:iic8-2} $f(c)$, \begin{equation} f(c) = \int\limits_{0}^{\infty} \mathrm{exp}(-t^{2}-\frac{c}{t^{2}}) \mathrm{d} t \label{eq:iic8-3} \tag{3} \end{equation} so that  \begin{equation} \mathrm{L}(a,b) = \frac{f(ab)}{\sqrt{a}} \label{eq:iic8-4} \tag{4} \end{equation} In equation \eqref{eq:iic8-3} we let $y=\sqrt{c}/t$ \begin{equation} f(c) = \sqrt{c} \int\limits_{0}^{\infty} \mathrm{exp}(-y^{2}-\frac{c}{y^{2}}) y^{-2} \mathrm{d} y \label{eq:iic8-5} \tag{5} \end{equation}  Combining equations \eqref{eq:iic8-3} and \eqref{eq:iic8-5}, we have \begin{equation} f(c) = \frac{1}{2} \int\limits_{0}^{\infty} \mathrm{exp}(-t^{2}-\frac{c}{t^{2}}) \left(1+\frac{\sqrt{c}}{t^{2}} \right) \mathrm{d} t \label{eq:iic8-6} \tag{6} \end{equation} Now we let $s = t - \sqrt{c}/t$ \begin{equation} f(c) = \frac{\mathrm{e}^{- 2\sqrt{c}}}{2} \int\limits_{-\infty}^{\infty} \mathrm{exp}(-s^{2}) \mathrm{d} s = \frac{\sqrt{\pi}}{2} \mathrm{e}^{- 2\sqrt{c}} \lim_{z \to \infty} \mathrm{erf}(z) = \frac{\sqrt{\pi}}{2} \mathrm{e}^{- 2\sqrt{c}} \label{eq:iic8-7} \tag{7} \end{equation} Combining equations \eqref{eq:iic8-1}, \eqref{eq:iic8-4}, and \eqref{eq:iic8-7} yields our result.


How do a tile with diagonal lines in Photoshop?

How does one draw a tile with diagonal lines that can seamlessly tiled with Photoshop?


In august I will go to Japan to visit relatives and to make a trekking. In europe I usualy bring trekking meals with me, the kind of meals that you can easily prepare on a stove by just adding water.   Those meals are sealed in plastic and usually look like this:   I've never had any problems in Europe, but when I look up the regulations on traveling to Japan, I read various restriction, ranging from not being allowed to bring in any meat products, up onto dissolowence of milk, vegetable or egg products.  I could live without meat (there are vegetarian meals available), but the other ingredients would be a problem.  Does anyone have experience with bringing food into japan?


Let $G$ be an abelian group, and $\Phi:G\to \mathbb{R}$ is a function with the following property: $$\forall a,b\in G,~~ |\Phi(a+b)-\Phi(a)-\Phi(b)|<c$$  The problem asks to prove the existence of homomorphism, $\Phi^*$, where $\Phi^*:G\to\mathbb{R}$ and  $$\forall a\in G, |\Phi(a)-\Phi^*(a)|<c$$


I'm trying to study the following series: $$\sum_{n=1}^\infty \frac{n^n}{(n!)^2}$$ All the terms are positive. But I can't solve the limit: $$\lim_{n\rightarrow \infty} \frac{n^n}{(n!)^2}=\lim_{n\rightarrow \infty} \frac{n}{n^2}*\frac{n}{(n-1)^2}*\frac{n}{(n-2)^2}*...*\frac{n}{9}*\frac{n}{4}*n=\lim_{n\rightarrow \infty} \frac{n}{(n-1)^2}*\frac{n}{(n-2)^2}*...*\frac{n}{9}*\frac{n}{4}$$  the first term of the product tends to $\frac{1}{n}$ but I can't say that all the product is $<\frac{1}{n}$ because the other terms  are $>\frac{1}{n}$  how can I solve it?


I recently reformatted my hard drive, so I downloaded QGIS so I could install it again. But now that I have, I seem to be missing all of my geoprocessing tools. Normally there were quite a few available from the drop-down Vector menu. Now there are only a handful. Also, I can't find the processing toolbox that I used to use, not sure what that was called but it seems to be missing now. It was where you could access all of the geoprocessing commands including GRASS.


I used dual boot Windows 7 and Ubuntu 12.04. And I want to remove Ubuntu from my PC. I tried   And I have two problems:   After I deleted my Linux partition, I tried to expand other spaces. When I clicked on them, the "extend volume" option was passive. I don't have the Windows installer disc, so I tried to create a Windows repair disc. But when I clicked "create disc" button, I got an error message. It said that "there is no media in the device."


Double dual of the space of bounded operators on Hilbert space

Every Banach space $X$ is canonically, isometrically embedded in its bidual $X^{**}$. But it is not always $1$-complemented in the bidual: for example, there is no projection from $\ell_\infty$  onto $c_0$, although $c_0^{**}=\ell_\infty$.  Let $\mathbb{H}$ be a separable Hilbert space, then the bounded operators $\mathbb{B}(\mathbb{H})$ form a Banach space. How to show that this space is $1$-complemented in the bidual, meaning there exists a linear contraction  $\tau:\mathbb{B(H)^{**}}\rightarrow \mathbb{B(H)}$ such that $\tau(T)=T$ for $T$ in $\mathbb{B(H)}$?


When trying to render my objects will not turn out in the render view

I have tried the Ctrl+Alt+H shortcut and in the first picture everything is supposed to render. Any help is appreciated and if there is any need for clarification I will answer as soon as possible.  Here is the render view for reference


Getting 404 error when trying to flag question or answer

I am unable to flag any question or answer on Stackoverflow mobile website. In flag pop-up, when i click '  it doesn't belong here, or it is a duplicate' radio button, it throughs error 404 instead of displaying sub-menu options to flag. This is happening from last two days, someone pls help! Any help would be appreciated.


Whats the difference between the following? $n+k-1 \choose k$ ${{n+k-1}\choose{k-1}}$ ${{n+k-1}\choose{n}}$

$n+k-1 \choose k$  ${{n+k-1}\choose{k-1}}$  ${{n+k-1}\choose{n}}$  So I've been using $n+k-1 \choose k$ to r pick k objects from n objects allowing repetitions. In the following question though   How many ways are there to pick r objects from n objects when  repetitions are allowed and either both the first and the second  objects appear exactly once or both do not appear?   I was told that     If you want to select r objects from n and the order doesn't matter   and each object can be reapeted than the general formula is: ${{n+k-1}\choose{k-1}}$ or ${{n+k-1}\choose{n}}$   and now I'm just a bit confused on the difference between them, and the usage  cases. I am a beginner so a simple explanation would be appreciated!


Why does Heimdall teleport this character?

At the start of the "Avengers: Infinity War" movie:      Thanos and the Black Order have boarded the Asgardian ship, killed most of the inhabitants and beaten Thor and Hulk.   Then:      A wounded Heimdall teleports Hulk / Bruce to Earth for safety before Thanos kill him.   Why:      Didn't Heimdall teleport Thor instead? Isn't Heimdall more responsible for Thor than Hulk?


Can I estimate remaining battery life by measuring its voltage with the same MCU that it powers?

I'd like to estimate the remaining battery life of a battery that powers a microcontroller. Could I accomplish this by simply leading the battery into the MCU's built-in ADC?  My idea is that I could plot the voltage over time to figure out how much battery life remains. But would the change in voltage be noticeable? And would it be a problem that the same battery powers the MCU (and ADC)?


Prime ideals of a finite direct product ring

Is it true that any prime ideal of a finite direct product ring $R=\prod_{i=1}^nR_i$ is of the form $P=\prod_{i=1}^nI_i$, where $I_j$ is a prime ideal of $R_j$ for some $j$ and $I_i=R_i$, for $i\neq j$?   Any ideal of the form above is prime in $R$. Indeed, if $X=\prod_{i=1}^nA_i$ and $Y=\prod_{i=1}^nB_i$ are ideals of $R$ (where $A_i$'s and $B_i$'s are ideals of $R_i$) such that $XY\subseteq P$, then either $A_j$ or $B_j$ is a subset of a  prime ideal $I_j$, for some $j$. Hence either $X$ or $Y$ is a subset of $P$.  Any help/suggestion would be appreciated!


How to delay a cmd+Q in the same way as the Caps Lock is delayed?

On my Mid-2009 MacBook Pro the Caps Lock button has a convenient delay such that when I hit it accidentally it doesn't turn on immediately. Can I incorporate such a delay for another key combination? I would like to delay the cmd + Q shortcut such that when I accidentally hit it the application is not quit and I have time to recover.


OpenCV Python -> C++ : decimal digits precision and divergence

I am currently trying to translate a Python image detection algorithm in C++ (in order to use it in a smartphone app) using OpenCV.  I have similar results to a certain point, where the two algorithms seem to diverge due to the accumulation of small differences in the images: I am applying some transformations to the image, but the number of decimal digits in Python is much larger than in C++ (where I use CV_64FC1 matrices), so I get more and more different results after some iterations...  Do you have any idea on how to overcome this issue?  Thanks in advance :)  EDIT: here is a code that gives a different result in Python and C++  void conv2(const Mat &img, const Mat& kernel, Mat& dest) {   Mat source = img;   Point anchor(kernel.cols - kernel.cols/2 - 1, kernel.rows - kernel.rows/2 - 1);   flip(kernel, kernel, 0);   filter2D(source, dest, -1, kernel, anchor); }  void myFunc() {   Mat im = imread("3.png", IMREAD_GRAYSCALE);   im.convertTo(im, CV_64F);    int rows = im.rows;   int cols = im.cols;   int sze = 7;    Mat gauss = getGaussianKernel(sze, 1);   Mat f = gauss * gauss.t();   Mat fx, fy;   Sobel(f, fx, -1, 1, 0);   Sobel(f, fy, -1, 0, 1);   Mat Gx, Gy, Gxx, Gyy, Gxy;   filter2D(im, Gx, -1, fx);   filter2D(im, Gy, -1, fy);   pow(Gx, 2, Gxx);   pow(Gy, 2, Gyy);   Gxy = Gx.mul(Gy);    gauss = getGaussianKernel(sze, 38);   f = gauss * gauss.t();   conv2(Gxx, f, Gxx);   conv2(Gyy, f, Gyy);   conv2(Gxy, f, Gxy);   Gxy *= 2;    Mat Gxx_minus_Gyy = Gxx - Gyy;   Mat Gxy_squared, Gxx_minus_Gyy_squared;   pow(Gxy, 2, Gxy_squared);   pow(Gxx_minus_Gyy, 2, Gxx_minus_Gyy_squared);    Mat denom;   sqrt(Gxy_squared + Gxx_minus_Gyy_squared, denom);   // denom += numeric_limits<double>::epsilon();   Mat sin2theta = Gxy / denom;   cout.precision(dbl::max_digits10);   cout << fixed << sum(sin2theta) << endl;   exit(1); }   And Python:  def conv2(img, kernel):     source = img     kernel = cv2.flip(kernel, 0)     rows, cols = kernel.shape     anchor = (int(cols - cols/2 - 1), int(rows - rows/2 - 1))     return cv2.filter2D(source, -1, kernel, anchor=anchor)   def myFunc():     im = cv2.imread('3.png', cv2.IMREAD_GRAYSCALE)     im = np.float64(im)      rows, cols = im.shape;     sze = 7      gauss = cv2.getGaussianKernel(sze, 1);     f = gauss * gauss.T;     fx = cv2.Sobel(f, -1, 1, 0)     fy = cv2.Sobel(f, -1, 0, 1)     Gx = cv2.filter2D(im, -1, fx)     Gy = cv2.filter2D(im, -1, fy)     Gxx = cv2.pow(Gx,2);     Gyy = cv2.pow(Gy,2);     Gxy = cv2.multiply(Gx, Gy);      gauss = cv2.getGaussianKernel(sze, 38);     f = gauss * gauss.T;     Gxx = conv2(Gxx, f)     Gyy = conv2(Gyy, f)     Gxy = 2*conv2(Gxy, f)     Gxx_minus_Gyy = Gxx - Gyy     Gxy_squared = cv2.pow(Gxy, 2)     Gxx_minus_Gyy_squared = cv2.pow(Gxx_minus_Gyy, 2)     denom = cv2.sqrt(Gxy_squared + Gxx_minus_Gyy_squared)     # denom += np.finfo(float).eps;     sin2theta = Gxy/denom     print(cv2.sumElems(sin2theta))     exit()   The call to myFunc() prints the sum of the elements in the "sin2theta" matrix: Python gives 86587.44928456949, and C++ gives 86825.05505451805947814, which starts to make a pretty important difference.


windows 10 major update wiped GRUB, how do I recover partitions properly?

Windows 10 + Ubuntu 16.04 LTS dual boot on a Lenovo Laptop.. after getting nagged about an update... I have been dumped into the grub rescue screen  grub rescue>   and a lot of the help for dual boot linux users seemed to rely on ls showing you a valid partition..  none of the partitions I am seeing are returning as valid file systems  grub rescue> ls (hd0) (hd0,msdos5) (hd0,msdos3) (hd0,msdos2) (hd0,msdos1)   grub rescue> ls (hd0,msdos5)/ error: unknown filesystem.   I am told I should grab a USB live stick.. boot in .. but a little bit uneasy since most of these walkthroughs are from 2015 & seem to get people stuck..      can someone nail down exactly what is the proper procedure ..  UPDATE 1  I tried to utilize the boot-repair utility, used the default repair.. shutdown and restarted.. didn't work, still seeing grub rescue and the same partitions as before  UPDATE 2 Now going through testdisk, here's the latest output     UPDATE 3 Performed the quick scan, my files are seemingly there.. but when I do the deep scan I get this warning    Leaving everything marked for deletion.. in my experience I need to select the partition with the boot file in the root dir to be bootable, and unmark for deletion all the rest...


How do i create a function to test if the input contains any character?

I have this set of example here to test if the user has keyed in any data after he presses enter.  echo -n "Type a digit or a letter > " read character blank="" if  [ "$character" != "$blank"]; then         echo "You typed something" else     echo "Enter something" fi   The code above should be testing if the variable contains anything, but I can't seem to get it to work, any help ? Much appreciated.


I have clean installed windows 7 ultimate 64-bit OS, on my desktop.  Configuration: 4GB RAM, 500GB HDD Gigabyte motherboard, Nvidia graphics Card.  I have installed only few applications, which do not exceed 500MB, But When i check the c-drive is full, It has 40 GB capacity.  Does the OS is occupying the space ? Or the old unused windows version still resides in c-drive.     I have tried disk clean up tool, But it oly cleared 100MB of 40GB c-drive.  Please help me cleaning up the c-drive. Ideally i want to install android sdk in my machine.    Edit  While installing windows 7, i used delete option to clear the c-partition. Is that causing the Low Disk Space issue ?   I could have used format option instead of delete, i realized it later.    Now i am planning to increase the c-partition size, Is that a good idea ?   or   I have to re-install (clean) by using format option this time and then check the occupied space to increase c-partition size.  Thanks in advance


Is XP only awarded to the PC that delivers the killing blow?

I have been a DM for 35 years, and now we are embarking on 5th ed. I am playing a 1st level Barbarian. Due to Ideals and Bonds and stuff, I am letting other party members get the “kill” on stuff I have done basically all the damage to. The DM is only awarding XP to the final “kill shot” which means I am no XP. That would be fine if he was awarding me Inspiration, but he’s not...  Is there any guidance for DMs that I can show him that says I should get some of the XP for doing most of the damage to an opponent?


Question about the graph of the square root function

I know this question may be stupid but I've been studying for my test tomorrow and I'm so frustrated, I can't figure this one out. if we have a square root function like this: $y = \sqrt{x}$ wouldn't $y$ be both $+2$ and $-2$ for $x = 4$, so shouldn't the graph look like a quadratic graph?


Problem/Exercise: Schrödinger's cat (QM)

I've been struggling for a day with the following problem on Quantum coherent states, so I was wondering if you could tell me if I'm going in the right direction (I've checked the books of Sakurai and Weinberg but can't seem to find a satisfactory answer)     Suppose a Schrödinger cat state given by $|\alpha_+\rangle :=N(|\alpha\rangle+|-\alpha\rangle)$, where $|\alpha\rangle$ are the coherent states of the harmonic oscillator and $N$ is a constant of proportionality. Verify the relationship of Robertson-Schrödinger for $X$ and $P$ operators.   The solution is simple as we only have to calculate $\langle x \rangle$, $\langle p \rangle$, $\langle x^2 \rangle$, $\langle p^2 \rangle$, and $rel(x,p)$.   From the definition of coherent states, $a|\alpha\rangle=\alpha|\alpha\rangle$ and with $x=x_0(a+a^\dagger)$, I began by calculating $\langle x \rangle$ in the following way: \begin{align} \langle x \rangle  & = \langle\alpha_+|x|\alpha_+\rangle \\ & = (\langle\alpha|+\langle{-\alpha}|)x(|\alpha\rangle+|{-\alpha}\rangle) \\ \langle x \rangle & =\langle\alpha|x|\alpha\rangle+\langle\alpha|x| {-\alpha}\rangle+\langle-\alpha|x|\alpha\rangle+\langle-\alpha|x|-\alpha\rangle \\ & = \frac{x_0}{\sqrt{2}}(\langle\alpha|a+a^\dagger|\alpha\rangle+\langle\alpha|a+a^\dagger|-\alpha\rangle+\langle-\alpha|a+a^\dagger|\alpha\rangle+\langle-\alpha|a+a^\dagger|-\alpha\rangle) \end{align}  From the definition $a|\alpha\rangle=\alpha|\alpha\rangle$, we deduce $\langle\alpha| a^\dagger=\langle\alpha| \alpha^{*}$.   Moreover (I'm not entirely sure of this step), by replacing $\alpha'\rightarrow-\alpha$ we deduce that $a|{-\alpha}\rangle=-\alpha|{-\alpha}\rangle$ and $\langle{-\alpha}| a^\dagger=\langle-\alpha| {-\alpha^{*}}$.  Applying the operators to the above expression, we finally get:  $$\langle x \rangle=x_0 ((a+a^{*})+(-a+a^{*})+(a-a^{*})+(-a-a^{*}))=0$$  In an analogous manner, $\langle p \rangle=0$.   So far, is this correct? My main doubt comes with the eigenvalues of the coherent states for $|{-\alpha}\rangle$.


with mv, consider the path/name of the original file when choosing destination

Say I need to move the file /etc/dir1/dir2/dir3/a.out to /etc/dir1/dir2/dir3/b.out  Typing the whole path twice is tedious, and going to the directory might not be ideal. Is there a way to do such a move without retyping the directory?  On a related question (that I suspect has the same solution). Say I want to move a file someverybigfilename.png to somereallybigfilename.png. Is there a way to accomplish that without retyping the name?  (I know I can use a script. But does mv support some such thing natively?)  In short: how can I use move to partially alter/alter just a part of a filename? How to do a small change like extension?


I bought a laptop with Windows 8 pre-installed with a product key.  However, for sometime I get the issue that windows are not activated although a product key is inserted.  It also not allowing me insert the same product key again.  How can I resolve this issue?


What is the lifetime of a static variable in a C++ function?

If a variable is declared as static in a function's scope it is only initialized once and retains its value between function calls. What exactly is its lifetime? When do its constructor and destructor get called?  void foo()  {      static string plonk = "When will I die?"; }


Can Gandalf really turn Sam into 'something unnatural'

At the start of The Fellowship of the Ring Gandalf catches Sam eavesdropping on the conversation between him and Frodo about the true nature of the ring. Then Sam panics and pleas to Frodo:     ‘Mr. Frodo, sir!’ cried Sam quaking. ‘Don’t let him hurt me, sir!   Don’t let him turn me into anything unnatural! My old dad would take   on so. I meant no harm, on my honour, sir!’   Can Gandalf really do such a thing or is Sam just plain enough to believe that wizards are almighty?


Ubuntu 13.10 on SSD (system) and HDD (data). Missing /grub/i386-pc/normal.mod

I've got a HDD (750 GB) and a SSD (16 GB). I want to install Ubuntu (13.10) on the SSD, but because of its small size, I need to install /home, /var and /tmp on the HDD. After that, I would like to install Windows (system + data) on another partition of that HDD, but it is not important now.  I installed Ubuntu (I had formatted and partitioned the disk before), but when I restarted my laptop it said:   'error: file '/grub/i386-pc/normal.mod' not found.  grub rescue>'   I tried to reinstall Grub 2 using  tutorial (as sdXY I used sdb1, because it's the only one partition of my SSD), but it didn't work.  Can anybody help me, please?


How to disable IPv6 in Debian when sysctl.conf and GRUB_CMDLINE_LINUX doesn't work?

First,  if I issue sysctl net.ipv6.conf.all.disable_ipv6=1 from the command line after the system has started, I get the result I want -- IPv6 is indeed disabled.  Now for the problem of making this behavior persistent after a reboot.  It is easy to find suggestions for how to do this, usually they revolve around putting net.ipv6.conf.all.disable_ipv6=1 in a file in the /etc/sysctl.d/ directory or in the config file for sysctl itself, namely /etc/sysctl.conf. Other approaches mentioned include adding  GRUB_CMDLINE_LINUX="ipv6.disable=1"   To /etc/default/grub  This is mentioned e.g. here:    I've tried all of these, they don't work. ifconfig clearly shows that IPv6 is enabled for the interface. Again, if I just do a manual sysctl after booting, it disables it as expected.  sysctl -p does nothing for me, only writing the command verbatim as above works.  I've also tried putting the sysctl command in /etc/rc.local, which I know runs correctly from observing other commands I can put there. However, despite executing, it doesn't seem to take effect.  I've also tried other commands instead of just all.disable_ipv6, such as default.disable_ipv6 and enp0s3.disable_ipv6 (I've verified that enp0s3 is indeed my Ethernet interface).  This seems a bit similar to  to me, but I have no idea why this happens. I'm confident that all I had to do on a different system was simply to put this in a file in /etc/sysctl.d/.  One way to disable this which I already know of, beyond what I've tried, would be to recompile the kernel manually without IPv6 support. However, this is simply too much of a kludge, it is not reliable, and it is too much work to do and maintain.


trying to locate process on server which is sending spam email

I have a CentOS server running Exim, with a standard LAMP stack installed.  The problem is that there is a process that is sending out unsolicited emails, AND I do not know how to locate the process.  Here is what I have done:   I have done a tail /var/log/exim_mainlog to see what is going on.  This is some of the output:  2016-02-14 01:42:00 SMTP connection from (jabosupply.dcr103.com) [255.255.255.255]:33165 closed by QUIT 2016-02-14 01:42:00 1aUlhH-0006fx-UO => cpm147 <lstockings@site1.com> R=localuser T=local_delivery 2016-02-14 01:42:00 1aUlhH-0006fx-UO Completed 2016-02-14 01:42:03 1aUlhL-0006gS-RD <= AmeliaCruz@site2.com H=(site2.com) [255.255.255.255]:54467 P=esmtp S=25154 id=456dfg4.G880UOMSX255.255.255.255@lisalou.vegan$ 2016-02-14 01:42:04 cwd=/var/spool/exim 3 args: /usr/sbin/exim -Mc 1aUlhL-0006gS-RD 2016-02-14 01:42:04 1aUlhL-0006gS-RD => cpm147 <duke@site1.com> R=localuser T=local_delivery 2016-02-14 01:42:04 1aUlhL-0006gS-RD Completed 2016-02-14 01:42:04 SMTP connection from (site2.com) [255.255.255.255]:54467 closed by QUIT 2016-02-14 01:42:05 SMTP connection from [255.255.255.255]:40445 (TCP/IP connection count = 5) 2016-02-14 01:42:05 no host name found for IP address 255.255.255.255 2016-02-14 01:42:11 SMTP connection from [255.255.255.255]:58622 (TCP/IP connection count = 6) 2016-02-14 01:42:12 1aUlhU-0006hP-C9 <= GregoryLittle@site3.com H=(site3.com) [255.255.255.255]:48668 P=esmtp S=37419 id=DV59FTL1CMF.gfjh3ufdg45q1111.6603.WE@chimail1.m$ 2016-02-14 01:42:12 cwd=/var/spool/exim 3 args: /usr/sbin/exim -Mc 1aUlhU-0006hP-C9 2016-02-14 01:42:12 SMTP connection from (site3.com) [255.255.255.255]:48668 closed by QUIT 2016-02-14 01:42:12 1aUlhU-0006hP-C9 => cpm147 <duke@site1.com> R=localuser T=local_delivery 2016-02-14 01:42:12 1aUlhU-0006hP-C9 Completed 2016-02-14 01:42:17 SMTP connection from [255.255.255.255]:40445 lost 2016-02-14 01:42:17 1aUSE4-0000ZZ-Tp == erika.guerra@fresno.heald.edu R=dkim_lookuphost defer (-1): host lookup did not complete 2016-02-14 01:42:17 1aUj64-0004bS-6P Message is frozen 2016-02-14 01:42:17 1aULQ4-0002bv-Bs Unfrozen by errmsg timer 2016-02-14 01:42:18 1aULQ4-0002bv-Bs ** alisa_mckinney@site4 R=dkim_lookuphost T=dkim_remote_smtp H=smtp.secureserver.net [255.255.255.255]: SMTP error from remote mail server $ 2016-02-14 01:42:18 1aULQ4-0002bv-Bs alisa_mckinney@site4: error ignored 2016-02-14 01:42:18 1aULQ4-0002bv-Bs Completed  Tried turning off mail for the server via WHM - this is successful, but not a permanent solution! Done a top to see the exim processes.  There are anywhere from 0 to 1 to about 7 of them, with user of either root or mailnull.  So the hosted user account is not identified.   I am thinking there must be a PERL script or PHP script somewhere that is running this.  I need to identify it.  Can anyone help me locate the physical source of the script that is running.  P.S. My server is not high-use and none of the websites have mailing scripts.  I'm thinking this must have been injected so I am also changing passwords.  But my priority is to locate this.


I've been encouraged to use BibLaTeX, so I'm trying to, but I'm not meeting much success. I'm sure I'm doing something dumb wrong, but I don't know what. I am using TeXShop on a MacBook Pro running OS X Mavericks, if that's relevant.   I compile the following documents by running LaTeX, then BibTeX, then LaTeX twice more:   \documentclass[]{article}   \usepackage[autostyle]{csquotes}  \usepackage[  backend=biber,  style=authoryear-icomp,  sortlocale=de_DE,  natbib=true,  url=false,   doi=true,  eprint=false ]{biblatex} \addbibresource{bibshort.bib}   \usepackage[]{hyperref}   \hypersetup{colorlinks=true, }   %% ##############################   \begin{document}  Lorem ipsum dolor sit amet~\citep{kastenholz}.  At vero eos et accusam et \cite{GGK} justo   duo dolores et ea rebum~\citet{sigfridsson}.   \printbibliography    \end{document}   (taken almost verbatim from ) and  \documentclass{article}  \bibliographystyle{amsalpha}  \begin{document} \autocite{GGK}  \bibliography{bibshort}{} \end{document}   The results are as in this image:    The BibTex version is what I want. BibLaTeX version has no bibliography, parentheses instead of the brackets, and for some reason, unwanted spaces.  What have I done wrong?


get object size in bits with reflection in java

I want to get the size of the object I built with java.reflection. Here is the code. I don't understand what I'm doing wrong. When I get the object I'm tried to use instrument interface but it doesn't work. Thanks for helping !   public String analayzeData(Object obj) throws IllegalArgumentException, IllegalAccessException{         Class c =  obj.getClass();         System.out.println(sizer.getObjectSize(obj));         String dataText="*************Start of " + c.getSimpleName() + " Class*************\n";         Class superclass = c.getSuperclass();         if(superclass!=null && !superclass.isAssignableFrom(Object.class)){             Field[] superField = superclass.getDeclaredFields();             for(Field field : superField){                 field.setAccessible(true);                 Object fieldVal = field.get(obj);                 dataText+=field.getName() + " = " + fieldVal + "\n";             }         }     //  Instrumentation objectSizes =null;          Field[] fieldType= c.getDeclaredFields();         for(Field field : fieldType){             field.setAccessible(true);             dataText+=field.getName() + ":";             Object fieldVal = field.get(obj);             if(fieldVal instanceof ArrayList){                 ArrayList<?> arrayListField = (ArrayList<?>)fieldVal;                 dataText+="Size of " + field.getName() +" ArrayList = " + arrayListField.size() + "\n";                 for (int i=0; i < arrayListField.size();i++){                     dataText+=analayzeData(arrayListField.get(i));                 }                 dataText+="****End of " + field.getName()  + "List****\n";             }             else                 dataText+= " = " + fieldVal+"\n";         }         dataText+="*************End of " + c.getSimpleName() + " Class*************\n";         return dataText ;     }  } class sizer{     private static Instrumentation instrumentation;      public static void premain(String args, Instrumentation inst) {         instrumentation = inst;     }      public static long getObjectSize(Object o) {         return instrumentation.getObjectSize(o);     }  }


How come I often hear native speakers say "the (/ðiː/) US" as if "US" started with a vowel? It starts with a consonant /j/, right? Or are they using a strong form of "the"?  Thank you.


I know this question may seem duplicate, but having searched all the possibilities, I could not find exact answer to this problem. Having a surface, for example $x^2+y^2-z^2=-1$, and a plane, such as $x+2y+3z=0$, what are the major techniques to evaluate the distance between surface and plane? Any complete explanation will be strongly appreciated.   Note: In fact, I want to evaluate shortest distance by using Lagrange Multipliers. So if there is not any concrete method, any help towards "shortest distance" by using Lagrange method would also be kindly appreciated.


How do I get started creating an Ubuntu Desktop App?

I want to create an Ubuntu desktop app, specifically to replace Gwibber.  I can code in Java, Python and a few other technologies. Adobe Flex would have been an option until Adobe decided to suck some more and stopped support for AIR on Linux.  Note - I don't care about supporting other OS's. It will be a personal Ubuntu specific app. It can I open-source, I don't mind extra help.  It should integrate seamlessly with Ubuntu, notifications and all.  I guess Python it is, is that correct? How do I get started?


What is the probability one card from each suit will be represented when 5 cards are dealt?

If each suit is represented then we will have two cards from one suit and one card each from the remaining suits. So I am counting the ways this can happen like so -  ${52 \choose 1}$ ways of selecting the first card.  ${12 \choose 1}$ ways of selecting a card from the same suit as the first.  ${13 \choose 1}$ ways of selecting a card for each of the 3 remaining suits.  So I have -  $${52 \choose 1}{12 \choose 1}{13 \choose 1}{13 \choose 1}{13 \choose 1}$$  Then I have the sample space as $52 P 5$ as we are counting with regard to order on the numerator so we need to do the same for the denominator.  So I have $$\frac{{52 \choose 1}{12 \choose 1}{13 \choose 1}{13 \choose 1}{13 \choose 1}}{52P5}$$  Does that look correct?


What is the intuition for the point-set topology definition of continuity?

Let $X$ and $Y$ be topological spaces. A function $f: X \rightarrow Y$ is defined as continuous if for each open set $U \subset Y$, $f^{-1}(U)$ is open in $X$. This definition makes sense to me when $X$ and $Y$ are metric spaces- it is equivalent to the usual $\epsilon-\delta$ definition. But why is this a good definition when $X$ and $Y$ are not metric spaces?  How should we think about this definition intuitively?


Aren't these statements about confidence intervals equivalent?

I just read the following sentence from :      A 95% confidence interval does not mean that for a given realized interval there is a 95% probability that the population parameter lies within the interval (i.e., a 95% probability that the interval covers the population parameter).   Instead, the correct interpretation would be      The confidence interval can be expressed in terms of samples (or repeated samples): "Were this procedure to be repeated on numerous samples, the fraction of calculated confidence intervals (which would differ for each sample) that encompass the true population parameter would tend toward 90%.   But then my question is: if the current confidence intervals are an instance of an procedure that contains the true parameter value 90% of the time when time tends to infinity, like the second quote implies, then why can't we say that the current intervals contains the true parameter with 90% probability (the probability referring to the CI calculation, not to the parameter)? Isn't that the frequentest definition of probability?


Say I have a test - let's say for some chemical. I have 15 fields, which I divide in half. On the left side of the field, we dump some chemical into the field, on the right side, we do not. We record the bunny population before and three months after. Is it possible to construct a statistical test to say the chemical had NO effect, rather than trying to prove the chemical had an effect? Is this just a chi-square?


Manga about a guy trapped in a simulation/game

I read this manga maybe 2/3 years ago. He is given targets (usually women), which he at first thinks he can do anything with them (i.e. sexual assault). However, the system tasks him with actually figuring out a dark secret with each of his targets. He has the ability to 'scan' people, revealing some information about them. However, he cannot fully scan higher profile targets. He can buy extra items to assist him and will also be resurrected if he dies.


How can I align equations numbering vertically when using `\includegraphics` instead of typesetting the equation?

Here is the output I get when I use \includegraphics to import a figure in an equation environment:    But I want the output to be like this (edited photo):    My MWE:  \documentclass[]{IEEEtran}      \usepackage{graphicx}        \usepackage{amsmath}   \begin{document}   \begin{equation}     \includegraphics[width=0.8\columnwidth]{my_figure.png} \end{equation}   \end{document}


Trace of a $227\times 227$ matrix over $\mathbb{Z}_{227}$

well, I know that the trace is the negative of coefficient of $x^{226}$ of  the characteristic polynomial the matrix, but I dont know how the Char.Poly looks like in this case.please give me some hint. Do I   have to work in the splitting field of the characteristic  polynomial and add the eigen values to get the trace?but I dont know how.


Prove that an element in the quotient field is actually in the ring itself

Let $R$ be a noetherian integral domain and $K$ the quotient field of $R.$ Suppose $f \in K.$ Suppose for each maximal ideal $M$ of $R,$ we can find $h,k\in R$ so that $f = h/k$ and $k \not\in M$. Show $f \in R.$ Note: $R$ is not assumed a UFD! My attempt: I tried to prove that the summation of ideals generated by all the k that are not in some maximal ideals is the whole ring. But I dont know how to use that to move on. Also, I do not understand how to show an element is in the ring. I tried to prove that k has to divide h, but since R is not a UFD, I am not sure to achieve that.


Let $(X,d)$ be a metric space, and let $0 < a < 1$. Define $d^a$ by $(d(x,y))^a$. Show that $d^a$ is a metric on $X$.  I was able to show everything except the triangle inequality. It's obvious that we can write $$(d(x,z))^a\le(d(x,y)+d(y,z))^a$$ but I'm not sure where to go from there. Any hints? Sorry about the annoying format; I'm new to this site.


Scaled vs non-scaled PCA, which is more accurate?

So in this post:    The author explains a difference of scaling vs not scaling PCA. The two results differ quite a bit on the same data.  Which one then is more accurate and how to infer the accuracy and the need for scaling or not?


How is photosynthesis observed?    Say I have plants A and B, and I want to find how fast they are able to turn carbon dioxide into oxygen. How would I experiment this? Say I have one plant A, which has two kinds of leafs B and C. I hypothesize the B-leafs produce oxygen faster than the C-leafs. What kind of experiment could I set up to test this?


What is the quotient space $S^{2}\times S^{2}\times S^{2}/\sim$ topologically amd geometrically, where $S^{2}\subset\mathbb{R}^{3}$ is the unit sphere of $\mathbb{R}^{3}$ and the equivalence relation is defined as $$\left(p_{1},p_{2},p_{3}\right)\sim\left(p'_{1},p'_{2},p'_{3}\right)$$ iff there exists $T\in SO(3)$ (special linear group) such that $$T\left(p_{1},p_{2},p_{3}\right)=\left(p'_{1},p'_{2},p'_{3}\right)?$$ Thanks.


I am not a network person, so, I'm not sure how to ask this question.  Let's say we have our own DNS server that is local to our company.  Someone registers a new domain name or a change is made to DNS records and the authoritative name servers have been updated.  How does our local DNS server know about the new domain name or a change to an existing domain name?  I mean, a request has to come from our local network in order for our local DNS to even know about the name, right?  It's not like authoritative name servers push information to every DNS server automagically.  Am I'm correct that requests have to come from our local DNS servers in order for the local records to be updated?  And does that mean the only way our DNS servers will be updated is when a request is made for a domain name by a user?  thx


Suggestions on learning new languages allowed here?

I know C++, Python, JavaScript and Prolog.  I want to learn Java.  Will my question be deleted if I ask for recommendations on StackOverflow?  If so, is there another StackExchange site I can ask on?


Login to ubuntu server directly without ssh access

I have an ubuntu server running Ubuntu 18.04 that I can access remotely using ssh. However I also have a monitor and keyboard connected directly to the server and I want to create a user that is able to login this way directly and that is not able to login using ssh because I don't want remote access for this local user. I want to be able to use this user as an admin account that is only accessible if you have direct access to the physical server. Is this possible?


Is the universe infinite? Or is it finite?  If it is infinite,it's very difficult to imagine an endless space(though not impossible).  But if it's finite, the idea that we can't go beyond a certain space just creeps me out.  So, what is it actually?


Bounty Boost and Resurrect or Zero Response Bounty Return

I put out a bounty recently and got zero comments and zero answers.  It then expired.  I'd still like to get this question answered, and (if the feature existed) I would even go so far as to increase the bounty amount.  But given that I just put 50 reputation towards getting no response at all, it seems like a waste to put an additional 100 reputation towards it and hope for the best.  Here's two feature ideas that might help in this scenario:   The ability to resurrect an expired bounty by adding more rep to it. Getting bounty returned if there is zero response (no comments, no answers) to it.   Neither of these features seem particularly game-able, and would make it less of a risk to put bounties on uncommon issues.


Why is mass an invariant in Special Relativity?

I have read  that mass is an invariant and that it is the momentum that approaches infinity when your speed approaches the speed of light. That is why infinite energy is required to accelerate an object to the speed of light.  But, why doesn't mass increase as velocity increases? I have read that relativistic mass is $$m_{rel} = \gamma m$$ More generally, why exactly do we say that mass is an invariant?   EDIT:  is a good treatment on the controversy created by relativistic mass, and it covers why invariant or rest mass is preferable over the relativistic ones. But what I want to know, is why is mass invariant in the first place?


Has the black hole information loss paradox been settled?

This question was triggered by a comment of Peter Shor's (he is a skeptic, it seems.)  I thought that the holographic principle and AdS/CFT dealt with that, and was enough for Hawking to give John Preskill a baseball encyclopedia; but Kip Thorne is holding out, as are others.  Why?


equation 2 of  states that   $$ \lim_{t \rightarrow \infty} \sum_{i=0}^{t-1}(\alpha S)^i = (I - \alpha S)^{-1} $$  In this case $0 < \alpha < 1$ and the entries of $S$ are in the range $[-1, 1]$. How can I understand why this is true?


How do R and Python complement each other in data science?

In many tutorials or manuals the narrative seems to imply that R and python coexist as complementary components of the analysis process. To my untrained eye, however, it seems that both languages sort of do the same thing.  So my question is if there are really specialized niches for the two languages or if it's just a personal preference whether to use one or the other?


I have heard mention of late addition of extracts. I was under the impression that you need to boil the extract to kill off any possible nasties?  When I brew, so far always from a prepackaged kit, after the steep, I get the boil going, add the steep/rinse water, bring back to boil, add liquid extract, bring back to boil, add hops, boil 60 min, add finishing hops...  what would I gain or lose by waiting to add the extract? and how late into the boil is considered a late extract addition?  Thanks and Cheers!


How to upgrade to Windows 10 without losing Ubuntu or transfer data of Ubuntu to Windows

I run Ubuntu 14.04.3 LTS and Windows 8.1 in dual boot. Now I am getting the option to upgrade to Windows 10 but I fear that if I upgrade, it will delete Ubuntu from my system.  How can I upgrade to Windows 10 without losing Ubuntu? I have important data and it will take a lot of time to transfer my data to hard disk.  If there is a possible way to transfer my data from Ubuntu to Windows, it will also help me.


Why are many of my prisoners staying in their holding cell?

Although there is plenty of space for the 170 prisoners in my prison (capacity: 210), the prisoners stay in holding cells instead and leave many individual cells completely unoccupied. I can tell individual prisoners to go to unoccupied cells, but a day or two later, the prisoners end up back in the holding cells.   Any ideas why this might be happening?   All rooms are complete (enclosed, have toilet and bed) and range in quality from 3-10, with an average around 6-7.  Since the room quality feature just came out in Alpha-33 (my version), I wonder if it has something to do with that.  It's hard to tell whether this problem is a bug or a feature which I haven't learned about yet!


The intuition behind generalized eigenvectors

An ordinary eigenvector can be viewed as a vector on which the operator acts by only stretching (without rotating) it.  Is there a similar intuition behind generalized eigenvectors?  EDIT: By generalized eigenvectors I'm referring to vectors in the kernel of $(T-\lambda I)^k$ for some $k$.


Is there a Guide to Translate ArcPy code to GDAL equivalent?

Due to cost-cutting measures I've been asked if I can migrate ArcPy code to a GDAL equivalent.  I'm fairly new to GIS, ArcPy, and GDAL.  Is there a website or guide which caters to providing equivalencies between ArcPy and GDAL?  I am not asking for any specific script examples tailored to geoprocessing shape files.  I'm looking for an overall guide.  Or something in that direction.


JQuery Select on Dynamically Created Object

Hi I am creating some dynamic  elements here   function loadApiData(){ var url, jqxhr, url2, jqxhr2, status; for (i = 0; i < 11; i++) {     url2 = document.URL + 'status/' + i;     jqxhr2 = $.getJSON(url2, function(data) {         console.log('API response received');         //console.log(url2);         console.log(data);         status = data['status'];         //console.log(status);         if (status == false) {             //$('#false').append('
' + data['phone'] + ' phone Status: ' + status + '
');             $('#false').append('
' + data['phone'] + ' phone Status: <input type="button" id="' + data['phone'] + 'off" value="' + status + '" />
');         } else {             $('#true').append('
' + data['phone'] + ' phone Status: ' + status + '
');         }     }); }  };   However when I then try loading them later   function loadWindowSystem() {  $('#Nimoff').click(function() {     alert('hi'); }); };   I find that it doesn't actually register the click event.   My document.ready() looks like this.   $(document).ready(function(){ loadApiData(); loadWindowSystem(); });   Any help would be greatly appreciated.  Thanks  Resolved by using   $( document ).on( 'click', '#Nimoff', function () { // you code });


Prove that $\frac{a}{b} < \frac{a+c}{b+d} <\frac{ c}{d}$

I'm reading a introductory book on mathematical proofs and I am stuck on a question.     Let $a, b, c, d$ be positive real numbers, prove that if $\frac{a}{b} < \frac{c}{d}$, then $\frac{a}{b} < \frac{a+c}{b+d} <\frac{ c}{d}$.


Seasoning refuses to stick to carbon steel pan. Tried various techniques

Please before you mark this as a dupe, I did refer to this s.  I have a Matfer carbon steel that won't hold seasoning at all.  I first attempted the Cooks Illustrated .  I was very careful to follow the instructions carefully.     I got a nice root-beer colored seasoning that looked tough but food stuck to it like there was no seasoning at all and it came right off.  I redid this several times, each time I:   made sure each coat was very very very thin, wiped all but the sheen off baked the pan for a full hour each coat at 500F with full hour cool-down ensured each coat was not tacky applied 5 to 10 coats used very fresh pure flaxseed oil Completely cleaned the pan of seasoning between attempts with ovencleaner and scotchbrite   All very time consuming and ultimately ended in failure.  I also referred to  and followed the tips there.  I additionally followed everything on this  article.  I just can't get this to work.   I also tried a traditional seasoning.   That doesn't stay either.  I use wooden utensils.   The food just sticks and pulls the seasoning right off. I don't ever wash the pan.  One other thing I've noticed - on subsequent seasonings, no matter how thin I have the flaxseed oil on the pan, at the end of a baking cycle, it appears to pull together into little droplets.   Even with the oil practically wiped off the pan with just a nanometer thick coating.   I'm wondering if the oven cleaner messed up the pan or something.  It didn't do this when I first had the pan (though the seasoning still was a failure)  Any ideas?   I'm about ready to send this pan to goodwill.     Note I have no problem keeping seasoning on a lodge cast iron pan.


Porting Perl to C++ `print "\x{2501}" x 12;`

I am porting a program from Perl to C++ as a learning objective. I arrived at a routine that draws a table with commands like the following:  Perl: print "\x{2501}" x 12;   And it draws 12 times a '━' ("box drawings heavy horizontal").  Now I figured out part of the problem already:  Perl: \x{}, \x00        Hexadecimal escape sequence; C++:  \unnnn   To print a single Unicode character:  C++:  printf( "\u250f\n" );   But does C++ have a smart equivalent for the 'x' operator or would it come down to a for loop?    UPDATE Let me include the full source code I am trying to compile with the proposed solution. The compiler does throw an errors:  g++ -Wall -Werror project.cpp -o project project.cpp: In function ‘int main(int, char**)’: project.cpp:38:3: error: ‘string’ is not a member of ‘std’ project.cpp:38:15: error: expected ‘;’ before ‘s’ project.cpp:39:3: error: ‘cout’ is not a member of ‘std’ project.cpp:39:16: error: ‘s’ was not declared in this scope   #include <stdlib.h> #include <stdint.h> #include <stdio.h> #include <string.h> #include <iostream>  int main ( int argc, char *argv[] ) {         if ( argc != 2 )            {                 fprintf( stderr , "usage: %s matrix\n", argv[0] );                 exit( 2 );         } else {                 //std::string s(12, "\u250f" );                 std::string s(12, "u" );                 std::cout << s;         }        }


Please resolve an "argument"  Which of the following is correct:  Post an HTML snippet  Post a HTML snippet  I believe it's the first - that the sound/vocalization, not the spelling, is what requires "an" instead of "a"; in other words "HTML" has an "A" sound and is, thus, verbally, a vowel. Am I wrong? The second possibility grates on my ears, and is as dissonant as all get out.


Does the verb after 'set of' agree with 'set' or the plural noun that follows?

Does the verb after 'a set of + plural noun' agree with 'set' or 'noun'? For example:     'Law is a set of rules that govern/governs society.'


Reported multiple error signs when using the aligned environment

When I was trying to use the alignment environment in latex to write a function, I found it hard to insert \therefore or \because in the environment and there were a few error notice.`From the equation, we know that:  \documentclass{article}  %Prevent the ff \usepackage{microtype} \DisableLigatures[f]{encoding = *, family = *}  %Make full use of the paper \usepackage[letterpaper, margin=1in]{geometry}  %Necessary for Math Mode \usepackage{amsmath} \usepackage{amsthm} \usepackage{amssymb}  %For items \usepackage{enumitem}  %Add necessary new command \newcommand{\RR}{\mathbb{R}} \newcommand{\NN}{\mathbb{N}} \newcommand{\QQ}{\mathbb{Q}}  %1.5 space \usepackage{setspace}   \begin{document}   \textbf{Problem 1:}\\\\ \begin{enumerate}[label = (\roman*)] \item From the equation, we know that: \begin{proof} \begin{equation*}[] \begin{aligned}[] (\frac{a_{n+1}}{a_n})^2-1 &= \frac{2+a_n-a_n^2}{a_n^2}\\ {\because} 0<a_n<2\\ {\therefore} \frac{a_{n+1}}{a_n})-1 &>0\\ {\therefore} a_{n+1} > a_n >0 \end{aligned}  \end{equation*} We can know that the sequence is increasing. \end{proof}   \end {document}   There were multiple errors, how may I solve this?


I am having some fundamental issues with manipulating Lorentz transformation matrices using index notation. However I'm struggling to pin down what the actual issue is.  Hopefully my misunderstanding can be demonstrated by an example. It can be shown that$$(\Lambda^{-1})^{\mu}_{\,\,\,\nu}=\Lambda_{\nu}^{\,\,\,\mu}$$ If I then write $$(\Lambda^{-1})^{\mu}_{\,\,\,\nu}=(\Lambda^{T})^{\mu}_{\,\,\,\nu}$$ I have seemingly proved that $$\Lambda\Lambda^{T}=I$$ which is not true, given the definition of the Lorentz group. I have seen the equation $$(\Lambda^{T})^{\mu}_{\,\,\,\nu}=\Lambda_{\nu}^{\,\,\,\mu}$$ used in various places, so I can't really see what I've done wrong here.  If somebody could point out where I'm going wrong, and explain why, that would be so helpful! Thanks.  Edit: Possible duplicate doesn't seem to explain why I cant: a) Transpose and swap indices of a LT (eq. 4, used in going from eq. 1 to eq. 2) and/or b) Equate matrices, given equal elements (eq. 3) which are needed to solve my example.


I want to upload file data and a variable, when i submit a file it goes well. But if i append the variable there happens nothing. The thing what i see is the file data.   html:  <form id="articleData">     <input type="hidden" name="id" value="123" readonly="readonly">     Upload article csv: <input name="articleCsv[]" type="file" />
     <input type="radio" name="item" value="add">Add new items
     <input type="radio" name="item" value="update">Update items      <input type="submit" value="Submit"> </form>   This is my ajax request:  $("form#articleData").submit(function(event){   //disable the default form submission   event.preventDefault();   var checked = $('input[name=item]:checked', '#articleData').val();   //grab all form data     var formData = new FormData($(this)[0]);       formData.append('updateOrAdd',checked);    $.ajax({     url: "/spares/admin/importArticleCsv",     type: 'POST',     data: formData,     async: false,     cache: false,     contentType: false,     processData: false,     success: function (returndata) {       alert(returndata);     }   });    return false; });   my php:  public function importArticleCsv(){     $output[] = array();     $response[] = "";      $this->load->model('admin/csv');     $url = $_FILES['articleCsv']['tmp_name'][0];     $updateOrAdd = $_FILES;     print_r($updateOrAdd);     $header = NULL;     $data = array();  }   And the output of my print_r in the php code  Array (     [articleCsv] => Array         (             [name] => Array                 (                     [0] => Pmaster Inladen.csv                 )              [type] => Array                 (                     [0] => text/csv                 )              [tmp_name] => Array                 (                     [0] => /Applications/AMPPS/tmp/php/php7VNPlg                 )              [error] => Array                 (                     [0] => 0                 )              [size] => Array                 (                     [0] => 111216                 )          )  )   Where is my key (updateOrAdd) not in the array? I don't get it..


Do I need a visa for a connecting flight to Japan?

I'm going to the Philippines this October and would like to layover in Japan. I found a reasonably priced ticket with a 15-hour layover to Haneda, however, I have to transfer to Narita. Do I need a visa since I'm going to have to stay at a hotel and ride a bus to travel to Narita airport? Thank you!


Best printer for greeting cards that won't fade?

I'm so stuck and can't find an answer anywhere!  Which printer is the best for printing greeting cards and stationery? I don't want to outsource as I'd like full control over colours, fonts etc. So a home printer that will ensure that my graphics don't fade.  I print onto a thick, matte, slightly textured paper.  Thank you!


What to do if Relative Xpath is keep on changing

Below are my xpaths and keep on chining,  Element path
5.00%
   Here need to capture values (5.00%)....  Element Xpath  //*[@id="dijit_layout_ContentPane_23"]/div[2]/div[1] //*[@id="dijit_layout_ContentPane_24"]/div[2]/div[1] //*[@id="dijit_layout_ContentPane_90"]/div[2]/div[1] //*[@id="dijit_layout_ContentPane_91"]/div[2]/div[1] //*[@id="dijit_layout_ContentPane_151"]/div[2]/div[1] //*[@id="dijit_layout_ContentPane_152"]/div[2]/div[1]


Why does my CPU Usage reach 100% too often?

I'm using a dual-core processor and often see my CPU usage reaches 100%. I realize this may happen if I'm running too much applications, so when I know the computer starts to run slowly, I start to close my applications.  I usually run 4-5 applications simultaneously. Usually those are: web browser (Google Chrome), Adobe Photoshop, Notepad++, XAMPP, and Windows Task Manager. Usually I close tabs in my Chrome first, because I often browse the net with about 20 tabs/4 windows open, so I presume that would take much memory (bad habit, I know).  But even after closing Chrome's tabs or closing other applications, my CPU Usage often stays at high percentage - 72% at best, 100% at worst. I check the Processes tab on Windows Task Manager and usually found the System, System Idle Process, or services.exe taking the highest CPU process (could reach 60).  Why is this happening? And is there any solution?  EDIT I have T2250 @ 1,73 Ghz and 2.5 GB RAM


Ring with unity. Show that if ab units, then a and b are units.

Suppose that R is a ring with unity, $a, b \in R$ and that neither a nor b      is a zero divisor. If ab unit, then a and b are units.   I know that a ring with unity means that   $$\exists 1_{R} \in R:\forall a \in R: 1_{R}a = a = a1_{R}.$$  For an element $a \in R$ to be a zero divisor we must have $a \neq 0_{R}$ and there must exist an element $\hat{a} \neq 0_{R}$ such that $a \hat{a} = 0_{R}$ or $\hat{a}a = 0_{R}$. Therefore, the meaning of not a zero divisor would be that given $a \neq 0_{R}$ we must have for every $\hat{a} \neq 0_{R}$ that $a\hat{a} \neq 0_{R}$ and $\hat{a}a \neq 0_{R}$. Similarly, for b we then have $b\hat{b} \neq 0_{R}$ and $\hat{b}b \neq 0_{R}$.  For $ab$ to be a unit there exists $(ab)^{-1} \in R$ such that $(ab)^{-1}ab = 1_{R} = ab(ab)^{-1}$.  Now, I have to show that $\exists a^{-1}, b^{-1} \in R$ such that $a^{-1}a = 1_{R} = aa^{-1}$ and $b^{-1}b = 1_{R} = bb^{-1}$.  I have no starting point thus far so any hint(s) are greatly appreciated.


Why are box topology and product topology different on infinite products of topological spaces?

Why are box topology and product topology different on infinite products of topological spaces ?  I'm reading Munkres's  topology. He mentioned that fact but I can't see why it's true that they are different on infinite products.   So , Can any one please tell me why aren't they the same on infinite products of topological spaces ?


UK visa blank refusal letter without reason for refusal

I received my refusal letter today for my standard visitor visa application for the UK. However, the reason for refusal is not mentioned anywhere on the letter and it appears more of an unfilled template. How may I proceed after this? Do I contact them and how do I do that? or should I just reapply? I am currently living in Egypt.  Please check the attached letter.


How can I export all item ID's, Metadata and Names?

I am attempting to export a list of all item IDs, and metadata from  minecraft. I am using the FTB Unleashed pack. What I want is to write to file:  351:1 Ink Sac 351:2 Rose Red ... 368:0 Ender Pearl 369:0 Blaze Rod ... 2174:0 Naga Stone   Or something that I can convert to that with some regex etc.  NEI, and Item Resolver both only export item IDs. However this is not useful to me because some mod, heavily use the metadata value, to store a different item in the same ID space. The Vanilla Dye is an example of this.  I am coming the the conclusion I may just have to make it myself.  I would like this for computercraft fun. I many computercraft things return only the item id / metadata eg the ME Bridge and . Other computer craft mods (AE Peripheral, OpenCCsensors) do handle item names. However I am unwilling to add mods to the server. If a there is a mod I can use in single player to export all the ID, metadata and names, then I can use a computercraft program to parse it, that can run on the server. (I already have one working for ID/Name)


How to disable Bluetooth on startup Ubuntu 18.04?

How do you disable Bluetooth on startup? I found a few solutions but non of them worked, so I was wondering how can I create a script that will run on each system startup, and perform an action to kill the bluetooth service so I can manually enable it later when I need it?


How to put a period between the chapter number and chapter title with scrlayer-scrpage?

By default, the headings with scrrept, scrlayer-scrpage, and scrheadings are of the form "«number» «title»" in the headings for numbered chapters. I am wishing to change it to "Chapter «number». «title»" (i.e., add "Chapter" and the period). Moreover, the unnumbered chapters should have just "«title»" in the headings.  I read through several tex.se Q&A-pages and finally arrived at a bulky solution which goes great lengths to achieve that:  \documentclass[twoside=false]{scrreprt} \usepackage[automark,headsepline,footsepline,plainheadsepline,plainfootsepline]{scrlayer-scrpage} \usepackage{lipsum} \pagestyle{scrheadings} \lehead{}  \lohead{} \cehead{} \cohead{} \rehead{\normalfont\headmark} \rohead{\normalfont\headmark} \begin{document}  \addchap{Introduction} \lipsum[1-20]  \clearpage \let\oldchaptermark\chaptermark \let\oldaddchapmark\addchapmark \renewcommand{\chaptermark}[1]{\markboth{\chapapp\ \thechapter\autodot}{#1}} \renewcommand{\addchapmark}[1]{\markboth{#1}{#1}} \rehead{\normalfont\leftmark. \rightmark} \rohead{\normalfont\leftmark. \rightmark}  \chapter{The rise of the house of Usher} \lipsum[1-20]  \chapter{The fall of the house of Usher} \lipsum[1-20]  \clearpage \renewcommand{\chaptermark}{\oldchaptermark} \renewcommand{\addchapmark}{\oldaddchapmark} \rehead{\normalfont\leftmark} \rohead{\normalfont\leftmark}  \appendix \addchap{Bibliography} \lipsum[1-20] \end{document}   Is there some more automatic way in which all the additional commands could be issued in the preamble rather than inserted between \begin{document} and \end{document}?  An aside: In the main text, there should be no periods after chapter numbers or section numbers.


How to log out user from web site using BASIC authentication?

Is it possible to log out user from a web site if he is using basic authentication?  Killing session is not enough, since, once user is authenticated, each request contains login info, so user is automatically logged in next time he/she access the site using the same credentials.  The only solution so far is to close browser, but that's not acceptable from the usability standpoint.


What is the relationship between the size of a slit and wavelength in diffraction?

Almost everywhere I see the statement that diffraction gets stronger when the size of the slit is comparable to the wavelength. I would just like to know the logic behind. Could anyone help me please? I really need a simple and concise explanation. Thanks :)


django - convert a list back to a queryset

I have a handful of records that I would like to sort based on a computed value. Got the answer ... like so:  sorted(Profile.objects.all(), key=lambda p: p.reputation)   on a Profile class like this:  class Profile(models.Model):      ...      @property     def reputation(self):         ...   Unfortunately the generic view is expecting a queryset object and throws an error if I give it a list.   Is there a way to do this that returns a queryset  or...  Can I convert a list to a queryset somehow? Couldn't find anything like that in the django docs.  I am hoping not to denormalize the data, but I guess I will if I have to.  Update / Answer:  it seems that the only way to get a queryset back is if you can get all of your logic into the sql queries.   When that is not possible, (I think) you need to denormalize the data


I need to know how to swap between languages in Ubuntu 14.04.3 using  command line .


Why is King Arthur female? Why is Iskander tall?

I've watched both the Fate/Zero and Fate/Stay Night anime (including the Unlimited Blade Works movie), but none of the visual novels, so no spoilers from that unless they are light spoilers. One thing that bothered me was that despite the fact that heroic spirits are defined by the public opinion/view of them, some heroes had qualities that were in direct opposition of what the public thought.  We know that heroic spirits, being sealed on their Throne of Heroes, are meant to be completely unchanged. This is the entire point of the Throne of Heroes. But this seems to be in opposition of the previous fact that heroic spirits are defined by what others think they are. Then there are Counter Guardians who are completely different, I believe, in that they are not sealed on their Throne of Heroes.  One particularly important Counter Guardian of the series is Arturia, or Saber. Arturia is female, despite the fact that she was treated by even her contemporaries as male, and has gone done in history as male. In fact, there isn't even any small hint as to Arturia's gender being anything other than male in our history, or the history of the Nasuverse (I believe). This being true, shouldn't Arturia be male?  This not being the case shouldn't Arturia be erased, or else create instability in the World? Same with Iskander. In history he is known for being pretty short, even for a Macedonian. That he is very tall means there is an incongruity with human knowledge and true fact.  Furthermore, in the Unlimited Blade Works movie Archer is revealed to be Heroic Spirit Emiya. If Heroic Spirit Emiya is summoned before he is even a hero, or acquired his gift from the World, etc., then how is it that Heroic Spirit Emiya is even strong at all? The power of a Servant being based on their popularity at the time of their summoning, Emiya should be weaker than pretty much every other Servant, and then some.  Maybe I'm just over-analyzing things, or I have some misconception. In any case, answers are appreciated.


Prerequisite for Milnor Toplogoy from a Differential Viewpoint

I finished Introduction to Manifold by Loring Tu and I am interested to study this book by Milnor. But I didn't take a course in topology (other than the one I learnt from the appendix of Tu's book). Is this sufficient for me to read the book by Milnor?


How can I solve this string problem more efficiently?

How many bitstrings of length 4 exists, where there can't be 3 consecutive 1's in a row and can't be 3 consecutive 0's?  I solved it by writing out, by hand, all the combinations of bitstrings of length 4 and then counting how many there were that fulfilled the aforementioned criteria.  My answer is that a total of 16 bitstrings exist of length 4. The number of strings fulfilling the aforementioned criteria are 6. So there are 6 strings which do not have 3 consecutive 1's or 3 consecutive 0's.


MacBook Pro login screen characters replaced by question marks

I can't log in to my MacBook Pro. The log-in screen now has question marks in place of letters and won't allow me to type in the password box.


Feature Request: "WAKE UP and accept my answer please"

Sometimes you give an answer to a question where:   You know it is the right answer You know it resolves OP's problems There's no answer "better" than yours You have spent time and effort on it Other users like it with several upvotes   BUT  OP that asked the question does not accept it with the green checkmark.  What annoys me is not the mere -15 points on reputation because, as well said by Jeff, if the answer is a good answer, the community will upvote it. I would like to get the green checkmark on pending questions for two main reason:   Personal satisfaction (what I answered, helped and worked for real!) Curiosity (Did it work? Cool, I can "close the case" and remember this solution)   Bonus reason: 3.  Good breeding (why not?)  I know that the system warns a user to accept an answer when he/she leaves questions without accepted answers after X days but, from the answerer's point of view, there's no way to put some "pressure" on who asked the question. Ok, I could ping the user with "Did it worked?", "have you tried?", "What about my solution?", "Still alive?" but imho that is not a good, official, effective option.  This feature fits well in these scenarios (thanks ccornet):  - The OP is new, unaware that answers can be accepted.  - The OP forgot about the question, and due to sort order in their profile, never saw it again.  My proposal: Having received X upvotes and after Y days, is it possible to have a "WAKE UP" feature where you can send a private predefined message to the OP who asked the question?    You could realize it in different flavors: 1. A voice recorded "WAKE UP" screamed when user logs in. 2. A red bloody "WAKE UP" message on users activity. 3. A blinking horse head near username.    Obviously, this is just a provocation. This feature could be implemented with a SOFT PRIVATE and absolutely PREDEFINED alert message.


I'd like to allow users to record videos directly from their webcam. I haven't done much work with PHP but am stuck with it for this project. We currently have a system in place for video uploading and encoding, but nothing to actually access a user's webcam. How would you recommend I proceed?


League of Legends Client Beta - Where do recordings save to?

I have recorded a segment from a recent game from the new beta client replay feature. Where do those recordings get saved?  Client Beta Version: 6.22.3353521.3353110


How to replace a character by a newline in Vim

I'm trying to replace each , in the current file by a new line:  :%s/,/\n/g    But it inserts what looks like a ^@ instead of an actual newline. The file is not in DOS mode or anything.  What should I do?  If you are curious, like me, check the question  as well.


Is it "using an MD simulation" or "using a MD simulation"? MD stands for "Molecular Dynamics".   Since "M" is pronounced "EM", I thought it must be "an". I found both usages on the web through searching in Google.


Suppose there are ANOTHER time-like dimension with another speed of light $$C>>c$$  Would we notice that huge speed of light?  How to test the existence of such a huge constant or speed of light?  Would it violate causality? QFT? QM?


Are horadric caches bound to the act they were acquired from?

Since the latest patches, horadric caches have been dropping the same quality of loot regardless of difficulty.  What I would like to know is that if each horadric cache acquired has its loot table bound to the specific act they were acquired from.  For example, say I want to farm for Gloves of Worship, an act2 bounty-only legendary. Would I be able to acquire it from an act4 horadric cache but that was opened in Act2?  Or would I have to, instead, farm bounties from Act2 or Act4 only?


Larger footnote numbers with hang option not appearing as superscript in enumerate

I have the problem, that my footnote number does not appear as superscript at the word. Instead it appears as normal number directly after the word. This is part of a template I should use. However, the problem seems to be with the macro.  If I uncomment the macro, the footnote appears in the superscript, but is than also smaller at the bottom of the page. I already searched for a solution, but did not find anything.  So, how do I keep the footnote big at the bottom and also appearing as superscript? Also this is similar to the other question (), I had the specific problem with a macro in my template, which was apparently not correct.   \documentclass[fontsize=12pt,BCOR=15mm,DIV=15,a4paper,headsepline,headings=small,twoside,openright,fleqn,appendixprefix]{scrbook}  \usepackage[utf8]{inputenc} % Zeichenkodierung \usepackage[T1]{fontenc} % Trennung von Wörtern mit Umlauten \usepackage{lmodern}  \usepackage[hang,stable]{footmisc} %Große Zahlen in Fußnoten \makeatletter \def\@makefnmark{\hbox{\normalfont\@thefnmark}} \makeatother \let\footnotesize\small \begin{document} \begin{enumerate} \item First item\footnote{adfasdf} \end{enumerate} \end{document}


I would like to wash my bike.   Which cautionary steps should I take?  Which parts of a Bike are water sensitive?  Which steps should I take after bike wash?


As the title states my netbook keeps freezing on Ubuntu 17.04 keeps freezing on asus x205ta. I have looked at all the post about the freezing problems and what to do.  My problem is that nothing works at all. I can hit any combination of buttons and still nothing. I am not sure what to do or if it is just my netbook?  Specs for netbook:   Processor Intel® Bay Trail-T Quad Core Z3735 1.33 GHz Processor Operating System Windows 10 Memory DDR3L 1333 MHz SDRAM, 2 GB  Display 11.6" 16:9 HD (1366x768) Glare panel Graphic Integrated Intel® HD Graphics Storage 32GB eMMC Card Reader card reader (Micro SD Micro SDXC Micro SDHC ) Camera VGA Web Camera Networking Built-in Bluetooth™ V4.0 Interface 1 x Microphone-in/Headphone-out jack  2 x USB 2.0 port(s) 1 x micro HDMI  1 x micro SD card Audio Built-in Speakers And Microphone SonicMaster Battery 38 Whrs Polymer Battery Power Adapter Output : 19 V DC, 1.75 A, 33 W Input : 100 -240 V AC, 50/60 Hz universal Dimensions 286 x 193.3 x 17.5 mm (WxDxH) Weight 2.16 lbs (with Polymer Battery) Certificates UL, MIC, CE Marking Compliance, FCC Compliance, BSMI, Australia C-TICK / NZ A-Tick Compliance, CCC, GOST-R, CB, Energy star, IDA, Erp 2013, RoHS, JATE


I have a problem regarding the size conversion from the legend elements tab an the actual legend.


How do star- (wye) plus delta-connected windings provide a phase change every 30°?

From the  subsection of the Wikipedia article on :     The phase displacement between the two AC supplies is usually 30° and is realised by using converter transformers with two different secondary windings (or valve windings). Usually one of the valve windings is star (wye)-connected and the other is delta-connected. With twelve valves connecting each of the two sets of three phases to the two DC rails, there is a phase change every 30°, and harmonics are considerably reduced. For this reason the twelve-pulse system has become standard on almost all line-commutated converter HVDC systems, although HVDC systems built with mercury arc valves usually allowed for temporary operation with one of the two six-pulse groups bypassed.   I've looked at  and  answer, but I'm not familliar with the terminology or notation of phasor diagrams and their use in transformer winding connections.  Is there a simple way to explain how a star (wye)-connected and delta-connected set of windings can provide a phase change every 30°? How does this produce twelve equally-spaced pulses per cycle?  Image: "12 pulse bridge with thyristor valves" from .


Can the spell Creation make magic items? (Official rulings only)

Is there an official ruling or rule that determines whether the spell creation can be used to create a magic item?  I'd like to know if any of the developers have posted a ruling about this, or whether there are other rules somewhere in the game that explicitly specify whether it's possible.


Why extra memory for one struct datatype?

I have written a simple C code in which I have defined two struct datatypes dT0 and dT1. The dT0 datatype has one int elemnt (a) and one double element (r) whereas the datatype dT1 has two int elements (a and b) and a double element (r). Naturally I would think that the memory requirement for dT0 would be less than that of dT1 but to my surprise, when I try to print their sizes in main using sizeof(), I get the same memory requirement for both, that is 16. I was expecting 12 bytes for dT0 (4 for int and 8 for double) and 16 bytes for dT1 (8 for two ints and 8 for double). What am I missing?  #include<stdio.h> #include<stdlib.h>  typedef struct dType0 {   int a;   double r; }dT0;  typedef struct dYype1 {   int a,b;   double r; }dT1;  int main() {   printf("%d %d\n",sizeof(dT0),sizeof(dT1));   return(0); }


Will I be allowed to board flight at Mumbai with Schengen visa validitiy for the next day?

I am a first time traveler to Europe. I have booked by flight from Chennai on 27th July with two transits at Mumbai and then Abu Dhabi and reaching Frankfurt, Germany at 7 am on 28th July. My Schenghen visa validity is from 28th July to 11th August.  Departure from Chennai 1.10 pm on 27th July, reaching Mumbai, Onward flight from Mumbai at 7 pm on 27th July, reaching Abu Dhabi, onward flight at 2 am on 28th July reaching Frankfurt 7 am on 28th July.  I am being told that my immigration check would happen at Mumbai airport only and that airlines may deny boarding because the visa validity starts the next day. what should I do?


"more site stats on: Stack Exchange" shows/does nothing

Out of curiosity, while on Writers, I went to check out more stats on the right. I wanted to see how the stats looked on Stack Exchange rather than Area51 so I clicked on the link and was taken to the Sites page ... and nothing. Thinking it was something to do with Writers.SE from this page I went to the AI.SE (artificial intelligence) via the bubble's Visit Site button. Went to the the same link and got the same result. The links for both of these sites were  and  but the url I have in the address bar is . Aside from everything after the # being removed I would expect the expand=true would open up the bubble but not even this occurs. Having my Developer Tools open in Chrome 53.0.2785.116 m on Windows 7 does not show any errors in the console and the network tab doesn't show any missing files or anything. I went into Internet Explore 11.0.9600.17239 and Firefox 48.0.2. Both do the same thing. I assume that the point of these links are to open up their site's bubble on the Site's page which shows the stats like questions, answers and answered % rather than show something totally different but as explained they aren't even opening up the bubble


Would a prime be redundant with a fast zoom?

Now that I am finally getting a fast zoom (Tamron 17-50mm 2.8) I've been considering a fast prime to go with it, specifically a Sigma 50mm 1.4. Despite its shortcomings, it still does really nice subject isolation past f/2, which is important to me. I was wondering if it might be redundant since my zoom is already a pretty fast fixed aperture. Of course, 1.4 is two stops faster than 2.8, but as with all primes you have to stop it down to get sharp results.   The main thing I am worried about is that if I drop $500 on a Sigma, it won't get used because there is already something O.K. in that range. Basically, is two stops difference enough to make you want to switch lenses?  EDIT: Perhaps I should add and as may have already been mentioned, these $500 could go to a nice speedlight which could sove the low-light 'issue' you get with f/2.8 vs f/1.4.


I note that some people like to write the inverse hyperbolic functions not with the prefix "arc" (like regular inverse trigonometric functions), but rather "ar".  This is because the prefix "arc" (for arcus) is misleading, because unlike regular trigonometric functions, they are not used to find lengths (inverse trigonometric functions can be used to find arc length of ellipses like $x^2+y^2=1$) but rather find area of a sector of the unit hyperbola.  Which version should be preferred?  $\operatorname{arsinh}$ initially confused me as I did not know why "ar" was used.  However, some seem to prefer this notation as it is more of an accurate description of the function.


I was trying to solve the following exercise in Hatcher (1.3.8). Let $p:(\tilde{X},\tilde{x})\to(X,x)$ and $q:(\tilde{Y},\tilde{y})\to(Y,y)$ simply-connected covering spaces. Assume $X,Y$ path-connected and locally path-connected spaces such that $X\simeq Y$. Then $\tilde{X}\simeq \tilde{Y}$. My thoughts: Let $f:X\to Y$ be a homotopy equivalence, $x_0\in X$. Define $y_0:=f(x_0)$. We get the following diagram.  There exists a unique lift of $f$ if $f_*(\pi_1(X))\leq p_*(\pi_1(Y))=\{*\}$ called $F:(X,x_0)\to (\tilde{Y},\tilde{y_0})$ with $f=q\circ F$. Define $\tilde{f}:\tilde{X}\to\tilde{Y}$ by $\tilde{f}=F\circ p$. I want to show that $\tilde{f}$ is a homotopoy equivalence. I don't see why $f_*(\pi_1(X))=\{*\}$. Any thoughts?


Show asterix while entering password in Terminal

In recent versions of Linux Mint, Asterix is shown for password characters in Terminal. In Ubuntu, nothing is shown for more security.  How to make characters in passwords appear as Asterix in Terminal in Ubuntu?  Unlike , I don't want the password to be totally revealed.


Is there a conjecture or result such that if it's proven to be true would automatically prove (the Strong) Goldbach's conjecture?

I'm just wondering if there's any existing conjectures or results such that if they're proven to be true, Goldbach's conjecture would also be proven to be true. Additional Information: I've looked at the other post about equivalents of the strong Goldbach's conjecture here:  But what I mean here is a conjecture not equivalent to Goldbach's, that if proved would imply Goldbach's conjecture is true.


Can a folder connection in ArcMap Catalog window be added using Python?

I have created a set of general scripting tools for map automation, etc. In one of my tools a geodatabase is created in the workspace folder the script points to. Just out of curiosity, is there any way I can add a folder connection in the ArcMap catalog window once the GDB is created so the user doesn't have to manually create one (assuming they haven't already done so), or is that out of ArcPy's scope?


Where to ask design rationale, architectural choices and "when should I use" type of questions about Software Engineering?

I have some questions about programming paradigms, design choices, and why I should want to use X when I could also do it using Y.  Here are some examples:   Why should I use Async instead of spawning a new thread to do the job? Should I use for a relational database, an in-memory database, or a specific built-in data structure to process a set of objects X times? Why should I use a thread pool instead of using a for loop to spawn X number of threads?   These kinds of questions are only possible to answer by referring to concepts, internal workings, using pseudo code, or telling personal experiences (I used to use A for a number of years, but it failed in case B).  I feel that they are not suitable for Stack Overflow, because it looks more a place to find solutions to practical problems. I also think that these kinds of questions would be instantly downvoted and marked as too broad or opinion based.  These are more on the academic side of software engineering and development, so I guess  would be a better place to ask them, but I wasn't sure.  I didn't want to add chaos to either communities and make unnecessary work for moderators by asking unrelated questions, and that's why I'm asking here. Could you please help me figure it out?


What is an example of how a Hamiltonian can be decomposed in terms of Pauli matrices?

I need to see an example of how Hamiltonian, i.e. any Hermitian matrix, can be decomposed into a linear combination of Pauli matrices. I would prefer an option to do this in larger than 2 dimensions, if that is possible.


Child theme - overriding add_image_size by a child theme

I am trying to get my child theme to work and to overide one line of code in the main theme functions.php but I can not getting to work since I am totally green in php.  In my main theme functions.php I have:  add_image_size('portfolio-three', 300, 214, true);   When I change it directly, change the image size it works like a charm and resizes images in my portfolio page. But I want to include it in child theme. The code of the functions.php in child theme is like this:          <?php     function mytheme_child_scripts() {         if ( ! is_admin() && ! in_array( $GLOBALS['pagenow'], array( 'wp-login.php', 'wp-register.php' ) ) ) {             $theme_info = wp_get_theme();             wp_enqueue_style( 'mytheme-child-stylesheet', get_template_directory_uri() . '/style.css', array(), $theme_info->get( 'Version' ) );         }     } add_action('wp_enqueue_scripts', 'mytheme_child_scripts'); add_image_size('portfolio-three', 388, 214, true); ?>   And it does not work, nothing happens, no error and also no image resize. I do not know what to do here. Could anyone please help me with implementing it properly ?  Best regards! Jacek


PHP|MySql - cannot insert text contains apostrophe

[I am using phpmyadmin]  I want to insert the long texts which are a large description of a city or region.  It contains apostrophe and comma, but when inserted, comma is not a problem but the apostrophe are.   For eg.      ' Taunggyi's the administrative capital for the whole of Shan State. Perched on top of a mountain, it's also a busy trading post,   and the...',   It will an input from the user (type-in) to the text area on my website.  So it cannot define statically like other examples I found.   Current one  //php $name=$_REQUEST["name"]; //  //in insert query =>  '.$name.',    Have tried like below too, but not working.  '".$name."',   Any good ideas, please! Your help is most appreciated. Thank you!


A binomial inequality with factorial fractions: $\left(1+\frac{1}{n}\right)^n<\frac{1}{0!}+\frac{1}{1!}+\frac{1}{2!}+...+\frac{1}{n!}$


How to prepare renderable array for images that are not stored in public or private filesystem, but are delivered statically with module?

I have a piece of code that prepares renderable array for my images:  if( !empty($row['image_file_id'])) {   $row['thumbnail'] = array(     '#theme' => 'image_style',     '#path' => _mymodule_uri_by_id((integer)$row['image_file_id']),     '#style_name' => 'product_thumbnail_small',     '#attributes' => array(       'alt' => $row['image_alt'],       'title' => $row['image_title'],     ),   ); }   It works OK:    But I want to add else with image provided within a module. I still want this image to go thorough all image style processing etc. I want my theming colleagues to be able to simply not care if they'll ever decide to add some effects or change resolution. But of course this image is in module directory, not in public://. And it means this will not work:  else {   $row['thumbnail'] = array(     '#theme' => 'image_style',     '#path' => drupal_get_path('module', 'mymodule') . '/frontend/noimage.png',     '#style_name' => 'product_thumbnail_small',     '#attributes' => array(       'alt' => 'some universal stub',       'title' => 'some universal stub',     ),   ); }   It gives:    And browser tries to read that image from   This gives nothing (status reports says "access denied"), unless I manually place image in public://sites/default/modules/mymodule/frontend - but I don't want it to be in public file system, I want it to stay in module space. How can I make it work?


PlayOnLinux Help - Error: What's the reason for this apt-get install error?

So I recently tried to install playonlinux on Ubuntu 16.04 and it was installing but stopped halfway through the installation, so I closed it and that was where I messed up. Now every time I enter  sudo apt-get update   in the terminal the error is:  E: Type '--2017-01-12' is not known on line 1 in source list /etc/apt/sources.list.d/playonlinux.list   E: The list of sources could not be read.


How many planets were there in the Empire at the time of A New Hope?   Must be a real planet or large moon Must be inhabited by sentient beings Must be governed by the Palpatine's Galactic Empire.


Which theoretical models for quantum computing are polynomial-time equivalent?

There are different theoretical models for quantum computing like the circuit model or the model of adiabatic quantum computers.  Between which of these models exist polynomial-time reductions?  Note that this question does not aim to cover physical implementations of quantum computers which are already discussed .


Silverlight web application automation tools?

I am looking to automate our regression test cases for a silverlight application we have and was wondering if anyone has done this and could suggest tools that can be used to do this quickly.


Malaria pills needed for jungle trip in Chiang Mai?

I'm from Belgium and I'll be visiting China (Beijing & Zhangjiajie) and Thailand (Chiang Mai, Bangkok & Ko Samui) in July. I've googled something on a website my doctor gave me a year ago where I can look up which vaccinations you need for certain areas.   When it comes a 3-day jungle trip in Chiang Mai, the website is very vague. I'm planning to do such a trip, but the websites says something vaguely about malaria there. Do you know for certain if I should or should not take any malaria pills when I'm there?


I have an external hard drive and I did something which I shouldn't have done, and I am annoyed that many files are prompting me about Administrator permissions to move a folder.  They are regular files.  How do I reset all the permission on the external hard drive?


Subject-auxiliary inversions not associated with questions

Possible Duplicate:          Is there some rule governing the following, or similar, subject-auxiliary inversions (*"Rarely they do see the light of day", *"Never I have been so insulted")?     In fancy sit-down restaurants, you can order a large meal and halfway through the main course, take a little dead cockroach or a piece of glass out of your pocket and place it deftly on the plate. Jump up astonished and summon the headwaiter. "Never have I been so insulted. I could have been poisoned" you scream slapping down the napkin. You can refuse to pay and leave, or let the waiter talk you into having a brand new meal on the house for this terrible inconvenience. ()      Rarely do they see the light of day; it's generally judged to be in no one's commercial interest that they should. Just occasionally, however, like a seemingly dormant volcano, they explode into the open. ()


apt-get upgrade fails: "guvcview : Depends: libguvcview-2.0-0 but it is not installed"

EDIT: My question is a duplicate but my answer here is a bit different than the answer in the linked duplicate above.  I cannot install, remove, or upgrade anything using APT because of this error:  $ sudo apt-get upgrade Reading package lists... Done Building dependency tree        Reading state information... Done You might want to run 'apt-get -f install' to correct these. The following packages have unmet dependencies:  guvcview : Depends: libguvcview-2.0-0 but it is not installed             Recommends: uvcdynctrl but it is not installed E: Unmet dependencies. Try using -f.   I'm certain I can find and fix this error. I'm more interested in knowing why the entirety of apt is broken because of one program having a problem.  Edit: I can't apt-get dist-upgrade either:  $ sudo apt-get dist-upgrade Reading package lists... Done Building dependency tree        Reading state information... Done You might want to run 'apt-get -f install' to correct these. The following packages have unmet dependencies:  guvcview : Depends: libguvcview-2.0-0 but it is not installed             Recommends: uvcdynctrl but it is not installed E: Unmet dependencies. Try using -f.   apt-get -f install is met with this error:  Preparing to unpack .../libguvcview-2.0-0_2.0.5+ubuntu2~ppa1+1418-0ubuntu1~201702081552~ubuntu16.10.1_amd64.deb ... Unpacking libguvcview-2.0-0:amd64 (2.0.5+ubuntu2~ppa1+1418-0ubuntu1~201702081552~ubuntu16.10.1) ... dpkg: error processing archive /var/cache/apt/archives/libguvcview-2.0-0_2.0.5+ubuntu2~ppa1+1418-0ubuntu1~201702081552~ubuntu16.10.1_amd64.deb (--unpack):  trying to overwrite '/usr/lib/x86_64-linux-gnu/libgviewaudio-2.0.so.2.0.0', which is also in package libguvcview-2.0-2:amd64 2.0.4+debian-1 dpkg-deb: error: subprocess paste was killed by signal (Broken pipe) Errors were encountered while processing:  /var/cache/apt/archives/libguvcview-2.0-0_2.0.5+ubuntu2~ppa1+1418-0ubuntu1~201702081552~ubuntu16.10.1_amd64.deb E: Sub-process /usr/bin/dpkg returned an error code (1)   It should be noted that the file /usr/lib/x86_64-linux-gnu/libgviewaudio-2.0.so.2.0.0 does not exist on my system.  I can't do anything with APT because of this. I can't even remove an unrelated program. abiword is a text editor.  $ sudo apt-get remove abiword Reading package lists... Done Building dependency tree        Reading state information... Done You might want to run 'apt-get -f install' to correct these: The following packages have unmet dependencies:  guvcview : Depends: libguvcview-2.0-0 but it is not going to be installed             Recommends: uvcdynctrl but it is not going to be installed  lubuntu-desktop : Depends: abiword but it is not going to be installed E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution).   OS: Lubuntu desktop (Ubuntu 16.10)


Travelling from Afghanistan to Guatemala

I have been invited to an official training in Guatemala, so now I plan to go to Guatemala from Afghanistan and I will use the Morroco and Madrid airport as transit countries. So, please let me know whether I need Schengen Transit Visa or not?


Is there a rule that governs the value of $\frac{x^n-a^n}{x-a}$? For instance $\frac{x^{12}-1}{x-1}$ is equal to $x^{11} + x^{10}... +1$. How is this result obtained? There is no limit over here, so I don't think there is calculus used, also I'm still in a beginner stage in calculus.


Recovering Home folder after failure to boot

I have a small issue. I was having some issues in getting some libraries to work and to resolve it, i deleted some shared libraries by mistake(sudo ...).Now ubuntu fails to boot up but i can access the files from recovery mode. I can see my home folder intact but i cannot even run sudo nautilus as it says it shared libraries not found. The data in my home folder is quite important and i want retrieving it is important. I am running a windows dual boot, if it helps. If anyone could help copy the home folder to a windows drive from the terminal itself(as i can access it at recovery mode) it would be of immense help. Thanks.:-)


Show $x^p-t$ has no root in the field $\mathbb{F}_p(t)$

I don't think I fully understand.  Let's say there is a root $x_0 \in K=\mathbb{F}_p(t)$, where $p$ is a prime number.  Then $x_0 = \frac{P(t)}{Q(t)}$ for some polynomials $P,Q \in \mathbb{F}_p[t]$. We can assume $\gcd(P,Q)=1$  and $x_0^p-t= \frac{(P(t))^p}{(Q(t))^p}-t= \frac{P(t)^p-tQ(t)^p}{Q(t)^p} =0$, so coefficients of $P(t)^p, tQ(t)^p$ must be identical, which contradicts $\gcd(P,Q)=1$,   hence such $x_0$ does not exist and the polynomial has no root in $K$.   am I about right?    anyway, I would appreciate an explanation about $\mathbb{F}_p(t)$, what is $t$? what is the meaning of a variable which does not belong to any specific "world"? I cannot use $t$ as if it was a member of $\mathbb{F}_p$ and hence cannot assume $t^{p-1} = 1 \pmod p$...


Column view mode with Nautilus (like Mac OS X Finder)

I found a feature request at  but it doesn't seem easy to get a column view with Nautilus while with Mac OS X it's a default feature.  Have I missed something or is this not currently possible?


How to do a case-insensitive LIKE in a case-sensitive database?

My vendor requires the data warehouse database to be case sensitive, but I need to do case-insensitive queries against it.  In a case-sensitive database, how would you write this to be case-insensitive?      Where Name like '%hospitalist%'


\eqref to give reference to a sequence of subequations

Suppose I have the following code  \begin{subequations}  \begin{align} a+b = c \label{eq.1}\\  d+e = f \label{eq.2} \end{align} \end{subequations}   I want now that upon giving the reference, it should appear as (1a-b). \eqref{eq.1} and \eqref{eq.2} will give output as 1a and 1b not what I want, which is (1a-b).


Python accesses multiple lists in a nested list. What's going wrong?

Python doesn't support multidimensional arrays, but I thought this workaround would be easy enough. It's just not working though. Here's my code  mat = [ [ None ] * 3 ] * 3 mat[0][0] = 1 return mat   Output  [[1, None, None], [1, None, None], [1, None, None]]   Why is it changing mat[1][0] and mat[2][0]? If I ask it to print mat[0][0] it just gives me 1 like it should.


Duplicate icons for manually created GNOME launcher items

I have downloaded Aptana Studio 3 and created the following launcher item for using Alacarte:  file: alacarte-made.desktop  [Desktop Entry] Comment= Terminal=false Name=Aptana Studio 3 Exec=AptanaStudio3 Type=Application Icon=/opt/Aptana-Studio-3/icon.xpm   Then, when I add the icon to the favorites and opens the Aptana Studio 3 I get two icons for it, one for launching new instances, and one for the currently running instance as per the following screenshot:    How do I force the application to use the same icon added to the favorites?


Unable to upgrade rooted 4.2.2 with OTA update 4.3

I bought my Nexus 4 from Google a while ago with 4.2.2 on it. It's using the stock rom, but it is rooted and has an unlocked bootloader.  When I try to install the OTA 4.3 update, the phone reboots and goes into Teamwin Recovery.  Then it looks like it tries to install it and then goes to the normal Teamwin recovery screen where I have to select Reboot > System to get back into the OS. And when I go back into the OS it's still 4.2.2.  What should I do? I think my best option is to manually install the update, but I don't know where it got downloaded to.


How to prove that $n! = n^n - C_{n,1} (n-1)^n +C_{n,2} (n-2)^n - \cdots $?

How to prove that $n! = n^n - C_{n,1}  (n-1)^n +C_{n,2} (n-2)^n - \cdots\,{} $?   I faced this problem when trying to find the number of onto  functions possible from one set having n elements to another set having $n$ elements.


how to unzip a zipped file which include various zip level files in unix/linux?

For example my folder name is  Test.zip  Test.zip includes various zip folders like te1.zip, te2.zip , te3.zip even te1.zip include various zip folders.    So i need to unzip in linux at once.  Could you please let me know how to do this.


I would like to simulate piping of a cream through a piping tip. I modeled the piping tip as you can see.  I added a soft body to the cylinder, and then I set the piping to collision.  But for some reason it doesn't go through instead it stops midway. I would like to render an image of the cream after deformation.  Do you have any idea how to create such an effect?


Will not allow me to install playonlinux! Says I have 'held broken packages

When I try to download 'playonlinux' I get:   The following packages have unmet dependencies:  playonlinux : Depends: icoutils but it is not installable                Depends: curl but it is not installable E: Unable to correct problems, you have held broken packages.   And I also can't install literally anything else.


I succeeded with @eblonde in the discussion () to smoothing polygons in R.   Code:  inter1= read.table("c:/inter2.csv", header=TRUE) #add a category (required for later rasterizing/polygonizing) inter1 <- cbind(inter1,                  cat                 = rep(1L, nrow(inter1)),stringsAsFactors = FALSE)  #convert to spatial points coordinates(inter1) = ~long + lat  #gridify your set of points gridded(inter1) <- TRUE  #convert to raster r <- raster(inter1)  #convert raster to polygons sp = rasterToPolygons(r, dissolve = T) # # Splining a polygon. # #   The rows of 'xy' give coordinates of the boundary vertices, in order. #   'vertices' is the number of spline vertices to create. #              (Not all are used: some are clipped from the ends.) #   'k' is the number of points to wrap around the ends to obtain #       a smooth periodic spline. # #   Returns an array of points.  #  spline.poly <- function(xy, vertices, k=3, ...) {   # Assert: xy is an n by 2 matrix with n >= k.    # Wrap k vertices around each end.   n <- dim(xy)[1]   if (k >= 1) {     data <- rbind(xy[(n-k+1):n,], xy, xy[1:k, ])   } else {     data <- xy   }    # Spline the x and y coordinates.   data.spline <- spline(1:(n+2*k), data[,1], n=vertices, ...)   x <- data.spline$x   x1 <- data.spline$y   x2 <- spline(1:(n+2*k), data[,2], n=vertices, ...)$y    # Retain only the middle part.   cbind(x1, x2)[k < x & x <= n+k, ] }  #addition transformation to distinguish well the set of polygons polys <- slot(sp@polygons[[1]], "Polygons") output <- SpatialPolygons(   Srl = lapply(1:length(polys),                function(x){                  p <- polys[[x]]                   #applying spline.poly function for smoothing polygon edges                  px <- slot(polys[[x]], "coords")[,1]                  py <- slot(polys[[x]], "coords")[,2]                  bz <- spline.poly(slot(polys[[x]], "coords"),40, k=3)                  bz <- rbind(bz, bz[1,])                  slot(p, "coords") <- bz                                  # create Polygons object                  poly <- Polygons(list(p), ID = x)                  return(poly)                }),   proj4string = CRS("+init=epsg:4326") )   #plot par(mar = c(0, 0, 0, 0)) Al = readShapeLines("DZA_adm0.shp") plot(Al, col = "gray") #plot(sp, border = "gray", lwd = 2) #polygonize result plot(output, border = "red",  add = TRUE) #smoothed polygons   My problem now I need to be represented on a map, in fact I'm looking methodology to clear the area outside my shapefiles.   Is that possible to do in R?


My question is simple:  Is the category of profinite groups an accessible category?  Thank you  Edit: I will add the (hopefully simpler) question:  Is the category of profinite groups complete and does it admit a cogenerator?