Why are so many energies in our universe mathematically represented by the equation $\frac{1}{2}ab^2$.  For example:    Kinetic energy $$\frac{1}{2}mv^2$$ Energy stored in a capacitor $$\frac{1}{2}CV^2$$ Energy stored in an inductor $$\frac{1}{2}LI^2$$   These are just some I can remember off the top of my head ,I remember that there are more like this. Is this just a coincidence or is there a reason behind this ?  I tried to google it but couldn't find any relevant results.

In the small amount of physics that I have learned thus far, there seems to be a (possibly superficial pattern) that I have been wondering about.  The formula for the kinetic energy of a moving particle is $\frac{1}{2}mv^2$.  The formula for kinetic rotational energy is $\frac{1}{2}I\omega^2$.  The formula for energy stored in a capacitor is $\frac{1}{2}C \Delta V^2$.  The formula for energy delivered to an inductor is $\frac{1}{2}LI^2$.  Finally, everyone is aware of Einstein's famous formula $e=mc^2$.  I realize there are other energy formulas (gravitational potential energy, for example) that do not take this form, but is there some underlying reason why the formulas above take a similar form? Is it a coincidence? Or is there a motivation for physicists and textbook authors to present these formulas the way they do?


I am trying to solve Exercise 8, Chapter 2 of Rudin's Real and Complex Analysis, but I am not sure of what I have done and I am not able to answer to the final part of the question. The requirement is as follows  Construct a Borel set $E \in \Bbb R^1$ such that $$0<m(E\cap I) < m(I)$$ for every nonempty segment $I$. Is it possibile to have $m(E)< \infty$?  My try on the construction: Let $E_0 =\emptyset$, and let $r_1, r_2, \dots$ be an enumeration of the rationals. For $i\geq 1$, do the following.  If there exists a nonempty segment $I_i=(a_i,b_i)$, with $a_i < r_i < b_i$, such that $m(E_{i-1} \cap I_i) = 0$, then let $m_i = \min\left(b_i-r_i,r_i-a_i\right)$ and $$E_i=E_{i-1} \cup \left(r_i-\frac{m_i}2,r_i+\frac{m_i}2\right).$$ Otherwise, if there is a nonempty segment $I_i=(a_i,b_i)$ with $a_i<r_i<b_i$ such that $m(E_{i-1}\cap I_i) = m(I_i)$, let \begin{eqnarray*} E_i &=& E_{i-1} - \left[r_i-\frac{m_i}2,r_i+\frac{m_i}2\right]=\\ &=& E_{i-1} \cap \left[r_i-\frac{m_i}2,r_i+\frac{m_i}2\right]^c,\end{eqnarray*} with $m_i$ defined as above.  $E = E_1 \cup E_2\cup E_3\dots$ is a Borel set, since it is obtained with a countable number of unions, intersections, and complements of open sets. Since any nonempty segment $I$ contains rationals, both $m(E \cap I)=0$ and $m(E\cap I) = m(I)$ would contradict the construction.  Question 1: Is my construction correct? Question 2: I would like to show that $m(E) < \infty$ cannot hold, in general. I would appreciate a hint on how to do that, if possible.

I was wondering how one can construct a Borel set that doesn't have full measure on any interval of the real line but does have positive measure everywhere.   To be precise, if $\mu$ denotes Lebesgue measure, how would one construct a Borel set $A \subset \mathbb{R}$ such that $$0 < \mu(A \cap I) < \mu(I)$$ for every interval $I$ in $\mathbb{R}$?   Moreover, would such a set necessarily have to contain infinite measure?


I'm trying to figure out how to proof the next thing: Let f be a periodic function in real numbers,that is there exists T> 0 such that f (x) = f (x + T) ∀ x ∈ R. Show that if lim x → + ∞ f (x) exists, then f is a constant function. Deduce from this that lim x → + ∞ sin(x) does not exist.

I have to prove that if a function f is convergent : $$ \lim\limits_{x\to +\infty} f(x) \in \mathbb{R}$$ and f is a periodic function : $$\exists T \in \mathbb{R}^{*+}, \forall x \in \mathbb{R}, f(x + T) = f(x)$$ Then f is a constant function.  Actually, this is obvious, but I can't figure out how to prove it formally ..  (I previously thought of this : , but it doen't work because I assume the periodicity hypothesis, and then I use it to prove a contradiction ..)  Thanks !


I've been thinking about this and it seems to confuse me more and more. Sure, at first site it looks to be half, but is it really half?   One can argue that for each even number there corresponds an odd number, but this argument can be challenged by saying that for each even number there can correspond two odd numbers which will mean the probability is a third...  Am I thinking wrong somewhere??

I know there's no uniform distribution for a countably infinite set, but I'm wondering if there's still a way to determine the probability of picking from a subset of a countably infinite set.  For example, what's the probability that I pick an odd number from the set of naturals, assuming I'm picking randomly? Is this even a coherent question? If so, is there a textbook approach to this problem in measure theory/probability theory/probability measure?  Thanks!


Prove that the derivative of an even differentiable function is odd, and the derivative of an odd differentiable function is even.

This is the question: "Show that the derivative of an even function is odd and that the derivative of an odd function is even. (Write the equation that says f is even, and differentiate both sides, using the chain rule.)"  I already read numerous solutions online.  was the official solution but I didn't quite understand it (particularly, I'm not convinced why exactly $dz/dx=-1$; even though $z=-x$).  Thanks in advance =]


Given that $$2017 = 9^2 + 44^2,$$ use this relation to find at least one group of positive integers $m$ and $n$ that satisfy $$2017^2 = m^2 + n^2.$$

For any natural number $n\ge 1$, given pairs $(a_1,b_1),(a_2,b_2),...,(a_n,b_n)$ of integer numbers, there exist integer number $c$ and $d$ such that  $$\prod_{i=1}^{n}(a_i^2+b_i^2) = c^2+d^2$$    My initial approach is  Base Case: $(a_1^2+b_1^2) = a_1^2+b_1^2$ which is true. (Although it is trivial)  Prove the statement is true when $n=2$: We have $$(a^2+b^2)(c^2+d^2) = (ac-bd)^2+(ad+bc)^2$$ (Thanks André Nicolas for pointing it out)   So if $a,b,c,d$ are integers, $ac,bd,ad,bc$ are all integers and integers are closed under addition and subtraction. Hence $(ac-bd),(ad+bc)$ are integers.   Inductive Hypothesis: $\prod_{i=1}^{n}(a_i^2+b_i^2) = c^2+d^2$ is true  Inductive Step: $$\prod_{i=1}^{n+1}(a_i^2+b_i^2) = \prod_{i=1}^{n}(a_i^2+b_i^2)\cdot (a_{n+1}^2+b_{n+1}^2) = (c^2+d^2)\cdot (a_{n+1}^2+b_{n+1}^2)$$  Where $c$ and $d$ are integers.   But when we apply $n=2$, we have  $(c^2+d^2)\cdot (a_{n+1}^2+b_{n+1}^2) = (e^2 + f^2)$ where $e$ and $f$ are integers.  Hence, by the principle of induction, the statement we needed to prove is true.


Quantities like position and time allow us to place our origin anywhere, but can the same be said for energy? I was thinking about the way we have defined the quantity gravitational potential, and for any finite distance from a 'planet' or a body, an abject would be said to have negative gravitational potential, conveying that a negative amount of work is done (in bringing the object from 'infinity' to that position, but this seems impossible as negative energy does not seem to physically exist (as far as I know). So, does negative energy really exist, or does it not (implying that negative work done is just another mathematical argument)?  Edit: The primary reason I ask this question is because I was wondering whether negative work done is fundamentally different from negative debts (when talking about money), or are they just the same - a mathematical convenience.

Sometimes we see energy that is negative, for example, the energy of an electron in orbit. We know energy is something that can do something. In this view does negative energy mean something opposite someway?


Tried two Illustrator versions, 2018 and 2020. The issue is, when I export as PSD it exports without layers as flat image.  Tried to google, found some workarounds, but all of them not working. Used Ungroup all and Release all layers options but still no luck. Also tried to do single files for each artboard, example attached 1.ai file is still not working, flatten when exported.

Is there a way to export large multi-layered Illustrator file to Photoshop?  When I export with preserve layers and text edit-ability, the complex layers are flattened. I've reorganized my layers to have simple groupings but that's time consuming.  Is there a more effective way of doing this? Or script to automate it?


Can I render the first half of an animation on my computer and the second half on my friends the make them video files and combine them?

Is there a way to use other computers that are sitting idle on my network to render my images?   From google, I've found , however it appears that is designed to let everyone use your hardware, in exchange for using theirs. Also, there is no guarantee to how soon your project will start rendering.   I have a bunch of servers sitting around that were bit coin mining. Is there a way to use them for blender?


This is my directory tree  Game/    a/       1.py       ...    b/       2.py   In 2.py I want import function display from 1.py. First I keep both file in same folder there is no problem.But how to import from other location?

Imagine this directory structure:  app/    __init__.py    sub1/       __init__.py       mod1.py    sub2/       __init__.py       mod2.py   I'm coding mod1, and I need to import something from mod2. How should I do it?    I tried from ..sub2 import mod2 but I'm getting an "Attempted relative import in non-package".  I googled around but found only "sys.path manipulation" hacks. Isn't there a clean way?      Edit: all my __init__.py's are currently empty    Edit2: I'm trying to do this because sub2 contains classes that are shared across sub packages (sub1, subX, etc.).  Edit3: The behaviour I'm looking for is the same as described in  (thanks John B)


When displaying the demographic datas from INSEE (), the results under qgis 2.2.0 is quite surprising :   instead of rectangles I just see triangles in the bottom right corner (so covering half the surfaces) the same shape file opened with MapInfo 10.0 seems correct with all the rectangles correctly displayed and filled.   I can't see the reason of such a difference, it seems for me to be a bug of Qgis ..

i have a problem with some geometry.  When i run the check geometry validity i get an error coming back that the rings are not closed, so recangular forms that i have surveyed are showing up as triangles. When I put the layer in editing mode, the rectangles show their rectangular forms but go back to triangles when i turn off the editing, not sure if this is caused by the codelist on my total station. a solution i found was to use polygons to lines and then lines to polygons and replace my original polygons with these new ones.  This can be quite time consuming so was wondering if anyone has a quicker fix for this or if there is a way of preventing this. The problem only occurs with polygons (i use a codelist created on a Leica TC1200)


I followed the steps exactly mentioned here  for connecting Talend v6.2 to salesforce.  The documentation states that we need to add 'Token File': the path to the token file that stores the refresh token used to get the access token without authorization.  But I am not getting how to generate Token File. Please help.

I followed the steps exactly mentioned here  for connecting Talend to salesforce.  I have done the configuration in Talend and added the test(sandbox) URL in the advanced setting. I am facing an error while trying to establish the Oauth connection (JWT) between Talend ETL tool and salesforce: {'error':'invalid_grant','error_description':'invalid assertion'} Here is the screenshot of the configuration and error message:   Please help to resolve this issue.


I have to split a 4K 10 minutes video into 120 small video files, each containing 5 seconds of duration. I'm using ffmpeg for splitting the video. The splitting take a very very long time and the speed of the conversion gets slower as the duration of the splitting gets higher. For test use, I used the commands below in cmd and a) was a lot lot faster than b):  a) ffmpeg -i video.mp4 -ss 0 -to 5 split.mp4  b) ffmpeg -i video.mp4 -ss 595 -to 600 split2.mp4  As the commands executed, there was a time delay and then the splitting starts happening and the time delay of b) was a lot longer than a). Please help me   or advise me to prevent this time delay and help me speed up my conversion. Please don't give me any methods which will cause certain amount of video footage to disappear. Thanks  ADDITIONAL QUESTION:  Is there any way to make the ffmpeg video quality conversion, fps conversion and video splitting faster through the computer specs. As to do I need to have a  more powerful graphics card to make the ffmpeg conversions faster or any other computer parts?

I have a video file of 30 minutes, but I want to extract a video from 00:09:23 to 00:25:33.   I can define the startposition with -ss, but I couldn't find one for the end position. Any help please?


I bought Ubuntu 19.10 from Ebay on a dvd and installed it that way, but have been having numerous issues since then, such as my Brother MFC-L2703DW not working even after downloading driver installation tool from Brother for MFC-L2703DW. Brother finally called me up and asked me to install Teamviewer, which I attempted to do for debian 64 bit, but kept getting "file not supported" message", same thing for 32 bit. My desktop is 64 bit. Brother support suggested I reinstall Ubuntu 19.10 latest vesion, but again the usb stick I have (32 GB) gives me message "no permissions" when I try to download from ubuntu to the usb. Brother then said I should reinstall Ubuntu this time from web and try using usb.   I downloaded .iso from Ubuntu website onto my hard drive. Then I used Ubuntu's own Startup disc creator software to flash my usb stick. However after I changed the bios boot sequence to usb first then rebooted, the first screen showing "ubuntu" or "advanced options" etc appeared but would not let me change the highlighted portion or would not start the flash. It was completely frozen. I tried rebooted and did the whole process again and again - no luck.   I tried again on a different machine using Linux Mint - same thing - the startup disc creator software just freezes up.   ANy ideas?

This question is asked often in Ask Ubuntu, sometimes with few hints about the situation.   Please provide a list of possible reasons to help troubleshoot the problem.


This is a two part question, and it might have to do with biology a bit.  Part 1: I grab a heavy dumbbell and curl it. Halfway up I stop the curl and just hold it there with my elbow at 90 degrees. There is no net acceleration, so there is no net force on the object, so no work is being done. But clearly I am using energy to do this, as my muscles are tensed. Since my chemical energy is not going into any sort of mechanical energy, is it simply going into heat?  Part 2: If we assume that all of the chemical energy of my muscles turns to heat, what if I now lift the weight? If I accelerate this weight up, now I'm converting some of this chemical energy into mechanical energy, so less can go to heat. Doesn't that mean your arms get hotter if you don’t do any work onto the object than if you do? This just seems counterintuitive to me.

I read the definition of  as  $$W ~=~ \vec{F} \cdot \vec{d}$$  $$\text{ Work  =  (Force) $\cdot$ (Distance)}.$$ If a book is there on the table, no work is done as no distance is covered. If I hold up a book in my hand and my arm is stretched, if no work is being done, where is my energy going?


I need to logout a user if the browser is closed. I'm using Drupal 8. I tried setting a session cookie in php. But the problem is the cookie should be 'httponly' and 'secure'.  Please suggest me the right method or is Drupal having such settings to achieve  this.  Thanks.

How to modify Drupal user's cookie so the cookie is not available anymore after a predefined time or when the user close his web browser or close all of the websites pages open in tabs ?  After some online searches i found that by setting the cookie lifetime to 0 should create temporary cookies that would be deleted once the browser is closed:  I first tried by modifing some ini_set() values in the settings.php :  ini_set('session.cookie_lifetime',  0); ini_set('session.gc_maxlifetime',   0);   I created a php.ini file located at the drupal site root, containing:  session.cookie_lifetime = 0;   But it does not work on my test site. Any ideas?


Why is one Coulomb equal to 6.24 *10^18 ? This number is weird . why wasn't it a nice number like 10^20. I have some guesses about this.

Why that exact number of electrons in one coulomb? who decided it? there is nothing wrong with the number, it just seems slightly messy. Why didn't the scientific community just settle on an easier number, such as $1\times10^{-19}$ for example?


Do you say program or programme? Which one is original english? Which one should we use?

I mostly have exposure to American English online. I am currently writing out a resume and need some help.   In Australia, in general, we write programme to mean a schedule or community programme. However with computer studies I'm inclined to write program to mean a computer program rather than the proverbial programme.  What is the correct spelling?


Suppose f is analytic function defined everywhere in $\mathbb C$ and such $z_0\in \mathbb C$ at least one coefficent in expansion    $f(z)=\sum^\infty_{n=0}c_n(z-z_0)^n$ is equal to $0$. Then prove that $f$ is polynomial   I understood that for each $z\in \mathbb C $ there exist some $n\in N$ such that $f^{(n)}(z)=0$ There is hint available for this problem says that use countability argument . I know that zero of holomorphic function is at most countable by Identity theorem. Here we get each $z$ some $n$. It does not say about for all $n$ some $n$ exist . I am not able to use hint. Any Help will be appreciated

Suppose $f$ is an analytic function defined everywhere in $\mathbb{C}$ and such that for each $z_0 \in \mathbb{C}$ at least one coefficient in the expansion  $$f(z) = \sum_{n = 0}^{\infty}c_n(z-z_0)^n$$  is equal to $0$. Prove that $f$ is a polynomial.  The problem hints to use the fact that $c_nn! = f^{(n)}(z_0)$ and use a countability argument.  My attempt at a solution  The only thing I can think of in this case is that the coefficients $c_n$ of the above Taylor expansion are defined as:  $$c_n = \frac{f^{(n)}(z_0)}{n!}$$  The only way one of these $c_n$ could be zero is if the derivative of order $n$ vanishes everywhere. Thus, this would mean that $f$ is a polynomial of order $k < n$.  Does this suffice as a proof? How would I use a countability argument to prove this instead? Thanks.


Can I, running Ubuntu 16.04 LTS, install, say, a driver for Ubuntu 14.04?  I'm running Ubuntu on a Parrot Chromebook and the touchpad doesn't work and neither do the F1-12 keys when I'm not holding down function. I know I can fix the touchpad with  drivers but there isn't a  for Xenial. There's only devel, saucy, trusty, and utopic. I want to know if installing the driver from one of the other repos would work or if it would mess something up.  Also, I'm very new to Ubuntu and don't understand apt pinning so, if that is the best way to do this, then could someone break it down so it's very simple?

I need these packages with the latest upstream version backported for ubuntu/natty   libccid_1.4.5-0ubuntu1_amd64.deb libpcsclite1_1.8.1-0ubuntu1_amd64.deb libpcsclite-dev_1.8.1-0ubuntu1_amd64.deb libusb-1.0-0_1.0.9-0ubuntu1_amd64.deb libusb-1.0-0-dev_1.0.9-0ubuntu1_amd64.deb opensc_0.12.2-1ubuntu1ppa1~natty1_amd64.deb pcscd_1.8.1-0ubuntu1_amd64.deb pcsc-tools_1.4.18-0ubuntu1_amd64.deb   I tried to build them from source with update but it failed. I am not an expert at packaging and there are so many tutorials and recipes out there.  Do you know a good and up to date tutorial for backporting Ubuntu packages?  How do I get packages from other releases without having to build them myself?


I changed my password a while back, and now want to change it back to THE ORIGINAL PASSWORD. But it says it is not strong enough. What can I do?  (I am using Ubuntu 14.04 on a lenovo think pad.)

When I install the Ubuntu, I set a short password(<4). Now I want to change the other short password by "passwd" or change passphrase on "Password and Keys" program, it needs a password >4 char.


I noticed, in the communities I'm subscribed to that if you click on the top left of the stackexchange community pull down menu, that it lists the questions of the community and when you click on 'Questions' in that community you get different questions.  Is there a difference in the two in the sorting of questions?

Just asked myself: Why isn't "Questions" the homepage? And why is the homepage only accessible with a click on the logo?  As far as I can see there is only one significant difference between the homepage and the Questions page: The sorting of the questions. And there is a sorting functionality on both pages - with different options though.  This doesn't make much sense to me. Is there a good reason for it?


script worked in the past, then was updated for 14.04.  #!/bin/bash  while true; do    val=$(sensors | awk '/temp1/ {print $2}')    max="+75.0"    if [[ "$val" > "$max" ]]; then        dbus-send --system --print-reply --dest="org.freedesktop.UPower" /org/freedesktop/UPower org.freedesktop.UPower.Suspend    fi    sleep 10    clear    sensors done exit 0   In 16.04 it gives an error:  Error org.freedesktop.DBus.Error.UnknownMethod: No such method 'Suspend'  Can it be updated so it would work in 16.04?

This is a radically updated version of the question. I have to update this because  is flagged as duplicate of this one, while this has no valid answer anymore.     Initial version of this question, which had the 11.04 tag:   I am new to scripting and linux, my comp gets too hot sometimes and I want to make a script to detect temp1 and if it's over 65 C, it must put it to sleep. I have a diffuculty at comparing values in the script, I couldn't manage to define figures correctly, would anybody fix it please? Here is my stab at it so far   #!/bin/bash  max=65  val=$   sensors | grep '^temp1:' | sed -e 's/.*: \+\([+-][0-9.]\+\)°C.*$/0\1/'  while true; do     if [[ "$val" > "$max" ]]; then         sudo /etc/acpi/sleep.sh force         sleep 1     else         sleep 10     fi     clear     sensors done     The above got  with  a script that according to the comments was at some point updated to work in 14.04:   #!/bin/bash   while true; do     val=$(sensors | awk '/temp1/ {print $2}')     max="+75.0"     if [[ "$val" > "$max" ]]; then         dbus-send --system --print-reply --dest="org.freedesktop.UPower" /org/freedesktop/UPower org.freedesktop.UPower.Suspend     fi     sleep 10     clear     sensors  done  exit 0     As indicated in the linked question, the above script doesn't work in 16.04.   That question got  with a simplistically modified version of the script:   #!/bin/bash   while true; do     val=$(sensors | awk '/temp1/ {print $2}')     max="+75.0"     if [[ "$val" > "$max" ]]; then         systemctl suspend     fi     clear     sensors  done  exit 0   But while it does the job (the system goes to sleep when going above 75), it takes more CPU power than expected and pushes the temperature up while running up to 10 degrees celsius; this is more useful, more cooling when not running!  I don't know if the problem is with the initial 11.04 script or with the last change but this needs a fresh answer for 16.04.


I have two mathematical sets that have no common elements.    In mathematical terms, these are called 'disjoint sets', and together they are called a 'partition'.  What common or well understood word or phrase could I use to explain what these are, when speaking to someone who doesn't know what a disjoint set or partition is?  Edit: I am looking for an alternative to the answer found in . I am looking for a reasonably common word/phrase to replace "disjoint". The other answer found in the linked question, "orthogonal", is much too obscure for my purpose.

I'm looking for a word for when you have a collection A and a collection B and they have no overlap.  In mathematical terms: the relation between two sets where the intersection is empty. Like in this Venn diagram:    The word that keeps popping up in my mind is disparate sets, but I don't feel that completely covers the meaning when I look at the definition, because that doesn't seem to preclude overlapping sets that are different:     disparate   1. distinct in kind; essentially different; dissimilar:   disparate ideas.


I'm trying to write \overset{\circ}{W}_2^{1,1} so that the circle lies on top of W AND the {1,1} superscript is not spaced differently due to putting the circle on W. So effectively I want the superscript {1,1} to appear as it would appear if I did not write the circle on top of W. Suggestions?

When I type $\overset{\circ}{Z}^\lambda$ the lambda is placed slightly above and to the right of the circle. Is there a way to make it appear as a superscript on the Z? I tried $\overset{\circ}{Z^\lambda}$, but then the circle is too high and to the right.  As a bizarre aside: a friend uses the exact same code with no problem. However, when I type it into MathOverflow it looks the same as in my compiler (i.e. bad).


Apache/2.4.41 PHP 7.3.9 Windows 10 64bit   I have been using XAMPP without issue for months now, and this morning when I turned on my PC adn tried to accedd my databases via HeidiSQL I received some strange errors. They all seem to relate to users / permissions. I haven't (or don't recall!) changed any database user accounts, so this is confusing me.  Using HeidiSQL I can access my localhost and view the available databases. I can create a new database. When I click on the 'manage users' tabe the program freezes and i have to force close.  Using Phpmyadmin I can't get any further. Except there's a message displayed;     You do not have privileges to manipulate with the users!   I have a root user with no password as this is a local testing environment.  The whole localhost database setup is running painfully slow. My localhost has 25 databases, mosts Joomla / Wordpress so not huge.  I've checked that everything is running on the correct port, and I don't have multiple instances opened. I've restarted my PC numerous times, no change.  The mysql error log doesn't have anything unusual.  Is there anything else I should be looking at?

Error message:  You do not have privileges to manipulate with the users!   Appears in PhpMyAdmin using Mariadb 10.3.7 on MacOs High Sierra installation from Homebrew  I'm logged in as root installed and rebooted with multiple server options: Mysql 5.7, Mysql 8.0 Mariadb 10.2 and 10.3.7.  I've tried everything from granting tables, flushing the permissions.  I need to be able to edit users from the PhpMyAdmin page and its not allowing me even though I have root access (with password set)


When using ls to list files in a directory,   Is it possible to color the files only according to their file types (e.g. a regular file, a directory, a special file such as a socket, a symlink, ...)?

I understand ls uses dircolors to display colored output. dircolors has default database of colors associated with file extensions, which can be printed wiht the command  dircolors --print-database   From man dir_colors I read, the system-wide database should be located in /etc/DIR_COLORS. But this file does not exist on my system (Debian). How can I modify system-wide color settings for dircolors? Where does the command dircolors --print-database take the settings from, when no file exists.  I am aware that user can have user-specific file ~/.dircolors with his settings, but this is not suitable for me, since I need to change the settings for everybody.  A second questions is, whether it is possible to use 8-bit colors for dircolors. My terminal is xterm-256color.


I use the following code to add figures:  \begin{figure} \centering     \includegraphics[width=0.8\textwidth]{orig.png}     \caption{pic}     %\label{fig:awesome_image} \end{figure}   However the figure doesn't appear where it should. For example:  \subsection{A}  \subsubsection{a}  text  [the figure code]  \subsubsection{b}  text  [This is where the figure shows up]  \subsection{B}   What could be the problem? Thanks.

Is there any package or a method to force LaTeX to keep floating environments like table and figure closer to where they are declared?


Let's say I want to search for "mobile" with "android" tag, I use the following URL:    This works fine.  However, if a Human Verification step is needed, the square bracket is dropped after the verification, the URL then becomes:  ...  Is there a way to preserve the square bracket after human verification?

I clicked a tag from a user profile on a site where I don't have an account. The address was:        It then took me to the "nocaptcha" page which I passed (with flying colors) by clicking the magic checkbox. I was then redirected to the search, but with brackets that surrounded the tag removed:        Clearly the brackets should be retained through this captcha detour.


I'm using bibtex and I would like to know how to cite a @masterthesis. I've exported Mendeley's citations and it has only the @phdthesis style, which actually works. Is there any way to make work with @masterthesis instead? My bibliography at the end of the paper gets wrong.  I'm using abntcite.sty.  Here goes the code:  @masterthesis{Filho2016Automatic,     author = {Silva{ }Filho, P. F. F.},     institution = {Dissertação (Mestrado) - ITA},     pages = 159,     school = {Dissertação (Mestrado) - ITA},     title = {Automatic Landmark Recognition in aerial images for the autonomous navigation system of Unmanned Aerial Vehicles},     year = 2016 }   Thanks!!

I need to cite master thesis and the lecture notes into a document. But the problem with @masterthesis and @unpublished citations is they don't print an institution name in the pdflatex output of bibliography.   `\documentclass{article}   \usepackage{filecontents}  \usepackage[ backend=biber, style=numeric, sortlocale=de_DE, natbib=true, url=true,  doi=true, eprint=false ]{biblatex} \addbibresource{bibliography.bib}  \begin{filecontents}{bibliography.bib} @masterthesis{bhgt, title={Bike Model}, author={Fris}, year={2016}, school={University A}, address={XXX} } @unpublished{Map, title = {Electrical Engineering Book}, author={Koch}, howpublished = {Lecture Notes}, Institution= {University B}, year = {2015} } } \end{filecontents}  \begin{document}  Citation Test:  \cite{bhgt} and \cite{Map} \printbibliography  \end{document}`   I get this bibliography output:         [1] Fris. Bike Model. XXX, 2016.   [2] Koch. “Electrical Engineering Book”. Lecture Notes. 2015.       Any suggestions, how we can also print an institute name?


As a follow-up to , consider the following situation:   Be a wizard of a level high enough to cast  Have a spellcaster friend that is willing to sacrifice himself "for the greater good" cast a beneficial concentration spell on you (for example, ) Sequester your friend while he is concentrating. This stops him in time, allowing the effects of bless to remain on you forever (or until something dispels either sequester or bless) Repeat the above for different casters and spells and enjoy a plethora of concentration effects on yourself (and why not your party as well)   This method appears to be only limited by how many spellcasters you can convince to be willing to be sequestered (starting a school/order promising "eternal life" may help).  Apart from being a cheesy plan that a DM is unlikely to allow, would this actually work by RAW?

The Sequester spell (PHB p.274) states:     If the target is a creature, it falls into a state of suspended animation. Time ceases to flow for it, and it doesn’t grow older.   If the target has spell effects with a duration in place is that duration suspended or does it continue to run down?


update cometchat set read='1' where id='18'      SQL Error 156:Incorrect syntax near the keyword 'read'.   Can you guys help me how do I do that?

One of my columns is called from. I can't change the name because I didn't make it. Am I allowed to do something like SELECT from FROM TableName or is there a special syntax to avoid the SQL Server being confused?


Looking for military  information, photos, rank, awards, duty stations, battles etc for Emil Fuchs. Born 7/25/1892, Deggendorf Germany.

Where can I find information on German soldiers from World War I and World War II?   I am curious to find out about my ancestors' role in the wars, i.e. what rank they had, where they where fighting, with whom and anything else.


It's just mentioned a shortcut for and its usage is supposed to be obvious, but it isn't obvious to me. How do I even tell I "marked" something? Why would I mark something? Does this thing have a scope? Does it ever expire? And do I get a bash warning when/where it did? And above all, cool, I "set mark". What now?  So, what exactly is this mark that I can set and what would I use it for?

I would like to be able to copy and paste text in the command line in Bash using the same keyboard bindings that Emacs uses by default (i.e. using C-space for set-mark, M-w to copy text, C-y, M-y to paste it, etc.).  The  says that Bash comes with some of these key bindings set up by default.   For example, yanking (C-y) works by default on my terminal. However, I can't get the set-mark and copy commands to work, and they don't seem to be bound to any keys by default.  Usually, the way a user can define her own key bindings is to add them to .inputrc. So I looked and found the following bash functions in the documentation that I presume can help me define the Emacs-like behavior that I want (i.e. set-mark with C-space and copy with M-w).  copy-region-as-kill ()      Copy the text in the region to the   kill buffer, so it can be yanked right   away. By default, this command is   unbound.   and    set-mark (C-@)      Set the mark to the point. If a   numeric argument is supplied, the mark   is set to that position.   If I understand correctly, the above means that copy-region-as-kill is not bound to any keyboard sequence by default, while set-mark is bound to C-@ by default.   I tried C-@ on my terminal, but I don't think it runs set-mark because I don't see any text highlighted when I move my cursor. In any case, I tried adding  keyboard bindings (M-w and C-) to the functions  copy-region-as-kill and set-mark above in my .inputrc and then reloading it with C-x C-r, but this didn't work. I know that my other entries in .inputrc work because I have other user-defined keybindings defined in it.  Is there anything I am doing wrong? Am I missing anything?


Below is my console out put I have no idea how to proceed with this, Can anyone provide some direction?  apt-get install mysql-server     Reading package lists... Done     Building dependency tree            Reading state information... Done     The following extra packages will be installed:       libaio1 libdbd-mysql-perl libdbi-perl libhtml-template-perl libnet-daemon-perl libplrpc-perl mysql-client-5.5 mysql-server-5.5 mysql-server-core-5.5     Suggested packages:       libipc-sharedcache-perl libterm-readkey-perl tinyca     The following NEW packages will be installed:       libaio1 libdbd-mysql-perl libdbi-perl libhtml-template-perl libnet-daemon-perl libplrpc-perl mysql-client-5.5 mysql-server mysql-server-5.5 mysql-server-core-5.5     0 upgraded, 10 newly installed, 0 to remove and 0 not upgraded.     E: Could not get lock /var/cache/apt/archives/lock - open (11: Resource temporarily unavailable)     E: Unable to lock directory /var/cache/apt/archives/

I get this error when trying to use apt-get:  E: Could not get lock /var/lib/dpkg/lock - open (11 Resource temporarily unavailable) E: Unable to lock the administration directory (/var/lib/dpkg/) is another process using it?     How can I fix this?


I am trying to create some PowerPoint templates for work and need to know what size images to use for the templates so they will look good on the screen. I tried making one with images that are 1024 x 768 pixels and when I view it on a large screen it looks awful.  I have searched and can't find any real clear guidelines for this.  Any help will be appreciated.  Thanks.

What's the dimensions of a presentation slide in pixels?   I'm having a hard time trying to get it right. I keep guessing and checking and it's taking too long. I googled some results and they're a bit off as well.  The other issue is that I'm using .opd format; the format proprietary to open office / libre office in windows 7.  I'm just trying to design a decent background for my presentation.


Years ago I recall reading a story by, I think, Isaac Asimov. Its central theme was phone exchanges becoming sentient.  Does anyone know what I am thinking about or am I dreaming and should quickly write this story?

I am looking for a short story I read long ago about the phone system 'waking up'. It talks about how the phone system had just reached the number of connections as the number in the human brain. They lead you somehow to wonder (maybe characters speculating?) and it ends with a 'baby cry' of all the phones in the world ringing. I think I read it at least 20 years ago, maybe as many as 30. I think it was after 1978 because I think it was after I went to work at Bell Labs - so the phone connection resonated:-). It was definitely pre-internet.   What was the title? Who was the author? Any more on the plot since my memory is very hazy? I remember really liking the story and this site has got me thinking about my ATF's.


So I was trying to use Django, which of course was broken out-of-the-box, and so in trying to correct it, I made the stupid decision to try and upgrade my Python from 2.x to 3.5...  Stupid me...  I foolishly followed a link to sudo apt-get install pythonsomethingorother and of course, because the link was not an "official" distribution, it too was broken. In an attempt to fix it, I decided to uninstall python 3.5 via sudo apt-get remove python3.5, which as you may be guessing, started to mess things up, bad. I saw Unity and gnome being clobbered and did my best to ctrl C (did nothing) and eventually managed to close the terminal by fanatically click the 'x' and such (it was a blur, I felt like I was dying).   But now things are... messed up, potentially pretty bad. The icon for firefox just came back as I am typing this, but was not there a moment ago. The regular terminal will not open, though I can open xterm. Every word I type has the red squiggly line underneath (dictionary got clobbered?) which is more annoying than anything, but a bunch of application icons seem to have gotten clobbered as well. I can still type up this question in firefox, and spotify is running, which is/are good news I think, but I am worried that if I close my laptop and come back, I will not be able to boot up the OS again. What can I do to salvage the situation? (other than reinstall python 3.5).   I should note that I am using Ubuntu 16.04, and installed using full-disk encryption. Having had problems booting and decrypting the disk prior, I was afraid to reboot the system (into windows dual boot or otherwise).  EDIT: I managed to more or less return my OS to its original state. I'll post what I did in case anyone else finds themselves in the same unfortunate position...  First, try using XTerm, since the gnome ("regular") terminal is probably broken. If you cant find or use XTerm, you can do the following:  MAKE SURE TO READ THE FULL SENTENCE/PARAGRAPH BELOW BEFORE ATTEMPTING  You can type ctrl + alt + f3 to open a virtual terminal. You will have to type in your username and password to log in, but then you can do sudo apt-get commands. You need to press ctrl + alt + f7 to get back to the graphical terminal. This is the default but if this does not work, try f4-f6.   Then:  sudo apt-get install build-essential checkinstall sudo apt-get install libreadline-gplv2-dev libssl-dev libsqlite3-dev tk-dev libgdbm-dev libc6-dev libbz2-dev cd ~/Downloads  wget https://www.python.org/ftp/python/3.5.0/Python-3.5.0.tgz tar -xvf Python-3.5.0.tgz cd Python-3.5.0 ./configure sudo make install   sudo apt-get install gnome-terminal (You can now use the "old" terminal)  and then:  sudo apt-get install gnome sudo apt-get install unity sudo apt-get install ubuntu-standard sudo apt-get install ubuntu-desktop sudo apt-get autoremove   Some of these may be a little overkill, but overall, I think I may have used 1 or 2 extra GB than I did before this whole catastrophe, which is a rather minimal cost for keeping my data and setup, in my opinion. I needed to reset a handful of settings, but another rather small price to pay. The system boots fine, and save for the settings, I have not noticed any other changes. Best of luck if you find yourself in the same position!  PS If you get any errors on the command with "libreadline" and the like, try the command without the packages that are causing problems.

I am a new Ubuntu user running Ubuntu 13.04.  I've been trying to install and use a DeDRM tool, but I've been having problems doing so. I was following some directions that said I needed a version of Python 2.7, but not anything Python 3.0 or later (because 3.0 versions are missing some necessary libraries?). I tried to install Python 2.7.5.6, but it didn't work. I thought it was probably because I had the later version of Python, so I went through terminal and removed Python 3.3, so I could install the earlier version of Python.  Now that I've uninstalled Python 3.3, a lot of applications no longer work, including the terminal and the Ubuntu Software Center. I have no idea how to fix this problem now.


I have installed Ubuntu on a desktop my parents use. All was fine. However I think they accepted a request to update the system and now when they switch it on (the machine only has Ubuntu) they see a long list of text ending with 'kernel offset: disabled'. The list begins with 'BUG: Unable to handle kernel NULL deference at [a load of numbers].' An image of what's I'm seeing is attached to this message.  I've been able to get back into ubuntu by choosing a previous version. The updated version is 4.4.0-64-generic. The version I can get into is 4.4.0-62-generic.   I don't want my parents to have to hold the shift key every time they switch on and choose this older version [the idea of them using Ubuntu is that it's simpler than Windows, which it is, so long as these things don't happen!].  So, what should I do now? I think I have a few options but I'd really appreciate guidance.   Re-install from USB and start again and choose not to do updates. Find a way to make UBuntu boot into the 62-generic version Undo the update of the kernel [I think this is the cause of the issue, based on my newbie reading of other questions]   Any help much appreciated.    EDIT: In a terminal I typed:   sudo apt-get purge linux-image-4.4.0-64-generic linux-headers-4.4.0-64-generic linux-headers-4.4.0-64  Then I rebooted and all's well. Phew. God bless you askubuntu! Sorry for polluting the site. But maybe it's ok to keep this posted for other newbies like me?

Ubuntu 12.04LTS  After an automatic kernel update through update-manager I cannot boot up without intervention any more. Latest version which GRUB boots automatically is 3.2.0-64-generic-pae which fails during startup at a blank screen.  [  2.140928] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block (0,0) [  2.141024] Pid: 1, comm; swapper/0 Not tainted 3.2.0-64-generic-pae #97 Ubuntu followed by a call trace, found at the end of the bootup in recovery mode.  It is not a disk error as I bootup properly with both 63 and 29. May be the same as  but maybe not. Others get the same message for unrelated (?) problems.  has a reply which suggests it might be the boot cd - my cd has simcity in it - a wine project I am working on - getting it working !!  I am obliged to use 3.2.0-63-generic-pae in order to bootup properly. How can I remove 64 and automatically bootup 63? I presume I have to edit a GRUB script but which and where is it?  If I physically remove 64 (how? which of the two shown below? do I need to make a new "generic" image?) will I then be deprived of future kernel updates which depend upon 64?  harveyp@harveyp:~$ sudo dpkg -l | grep linux-image [sudo] password for harveyp:  ii  linux-image-3.2.0-29-generic-pae       3.2.0-29.46 Linux kernel image for version 3.2.0 on 32 bit x86 SMP ii  linux-image-3.2.0-63-generic-pae       3.2.0-63.95 Linux kernel image for version 3.2.0 on 32 bit x86 SMP ii  linux-image-3.2.0-64-generic-pae       3.2.0-64.97 Linux kernel image for version 3.2.0 on 32 bit x86 SMP ii  linux-image-generic-pae                3.2.0.64.76 Generic Linux kernel image   has a reply which suggests ...  sudo apt-get purge linux-image-X linux-headers-X where X is the version that is giving you issues  but here too I am unsure what to do about the "generic" image as I have a pae 64 and a generic 64. And I don't wish to break it any more than it is already ...  Thank you for your help.


I've viewed  on a wide range of different browsers in the recent past, and every time it looked like this:    I don't know about you but to me, that vast expanse of emptiness in the center seems... superfluous, at best.   Is this intentional? Why not make the tabs go horizontal, or be two rows? I can't imagine why it would be desirable.  The screenshot was taken using Chrome 47.0.2526.111 on Linux.

I tend to keep my Chrome zoomed to 90% (it gives me more real estate on my work monitor. When I do the layout on , it breaks (see the image below).      `


I'm using windows 8.1 with an external hard drive. My external seems to go to sleep very quickly, like in a single minute. I constantly wait 2-3 seconds when accessing files on my external harddrive (where all my important stuff is). I have not had this problem on other OSs with this same external HDD.  I checked my power settings, its supposed to wait 40 minutes before spinning down (on battery and plugged in). This is clearly not happening. What might be the problem here?

I'm using Windows 8.1 with an external hard drive. My external seems to go to sleep very quickly, like in a single minute. I constantly wait 2-3 seconds when accessing files on my external harddrive (where all my important stuff is). I have not had this problem on other OSs with this same external HDD.  I checked my power settings, its supposed to wait 40 minutes before spinning down (on battery and plugged in). This is clearly not happening. What might be the problem here?


A lot of users find the 'reputation required' message on protected questions hard to understand, specifically when they've gained the network association bonus and they think they have earned enough reputation.  The dialog states (emphasis mine):     Because it has attracted low-quality or spam answers that had to be removed, posting an answer now requires 10 reputation on this site.   That isn't entirely true. This 10 reputation was gained on that site, but through the association bonus. Users simply don't get the association bonus doesn't count.  Can we change the wording? Maybe to something like this:     Because it has attracted low-quality or spam answers that had to be removed, posting an answer now requires 10 reputation on this site (excluding the network association bonus).   Or:     Because it has attracted low-quality or spam answers that had to be removed, posting an answer now requires 10 reputation gained through upvotes on this site.

I recently started an account on , and went to add an answer to a question which was protected. I have enough rep on other sites that I have the "Association Bonus", so I was confused as to why I wasn't being allowed to answer the question.     This question is protected to prevent "thanks!", "me too!", or spam answers by new users. To answer it, you must have earned at least 10 reputation on this site.   After re-reading the message and reviewing , I realized that the bonus didn't count as points earned toward that site.  This is a really minor issue, but I think it's worth fixing (not sure if bug or feature).  I believe that users who have enough rep to receive the association bonus should generally already know not to post "thanks!" and "me too!" style answers, so if the message is accurate, users who receive the association bonus should be able to answer protected questions.  If there's another reason to keep users from answering protected questions, such as  claim that:     For protected questions, you are expected to have experience on the target site itself. Experience at other sites is not enough.   then the message should be updated to reflect this.  Option 1:  make protected questions open to anyone who has >10 rep on that site and update the message to read:     This question is protected to prevent "thanks!", "me too!", or spam answers by new users. To answer it, you must have at least 10 reputation on this site.   Option 2:  leave protected questions the way they are, but update the message to read:     This question is protected to prevent "thanks!", "me too!", or spam answers by new users. To answer it, you must have earned at least 10 reputation on this site to show that you have experience on this topic; experience on other StackExchange sites is not enough.   Option 3:  Answer with your own suggestions/improvements to these ideas.


Taking $\nu_p(n)$ to be the p-adic valuation (returning the highest power of $p$ that divides $n$),  How would I go about proving that this function is completely additive for a fixed prime? I've done proofs for additive and multiplicative functions before but not sure how to go about this one since it has both a $p$ and $n$ element. Maybe I'm just complicating and confusing things in my head?

Let $n$ be a integer not equal to zero, $p$ a prime and $$|n|_p = p^{-\operatorname{ord}_p(n)}; |0|_p=0$$  Proposition: $|xy|_p=|x|_p|y|_p$  We want to show: $\operatorname{ord}_p(ab)=\operatorname{ord}_{p}(a)+\operatorname{ord}_p(b)$ So if we suppose there is a largest integral $v$ such that $p^{v}|(ab)$, then we can split up v such that $p^{v_1}|a,p^{v_2}|b$. If we suppose that there exist $v_1,v_2$ with them both being the largest integers such that $p^{v_1}|a, p^{v_2}|b$,  with $v_1+v_2= : v $ then $p^v|ab$. (I don't believe this to be a formal proof but rather my best own "idea" I can come up with...)  The script also mentions that the padic valuations' sums are bounded: $|x+y|_p\le \sup\{|x|_p,|y|_p\}$, how to show this?   Edit:   According to Robert Israel and Bill Dubuques answers, the first proposition is proven, if I understood correctly:   Given $ord(a)= v$ and $ord(b) = u$ which is the same as $a:= p^{v}m, b:= p^{u}n$ with $gcd(m,p)=gcd(n,p)=1$, because $ab=p^{u+v}mn$ with $gcd(mn,p)=1$ it follows that $ord(ab)=ord(a)+ord(b)$ and so $|xy|_{p}=p^{-ord(xy)}=p^{-(ord(x)+ord(y))}=|x|_{p}|y|_{p}$  Now to show: $|x+y|_{p}\le sup\{|x|_{p},|y|_{p} \}$  and the second can be tackled like this: set $a:=p^{v}m. b:=p^{u}n$, then checking two cases $1:(u=v)$ and $2:(v<u)$: $(a+b)=p^{v}m+p^{u}n= p^{v}(m+p^{u-v}n)$ so in case of (u=v) it follows that  $ord(a+b)= u = sup\{ord(a),ord(b)\}$  and in case of $(v<u)$ because the biggest v is $v:= u-1$: $ord(a+b)\le p^{u-1}(m+pn) \le p^{u}(m+n)= sup\{ord(a),ord(b)\}$  It seems that I did something wrong in both cases...


I always need to communicate with the TTL UART port on the MCU with a computer. When I talked about that, people always refer the UART port as an RS-232 port. Are they correct? If not, what is the difference between them?  Also, can I use a RS-232-to-USB converter for a TTL UART port?

Most of the time  and UART come together in serial communication theories. Are they both the same? From my readings I concluded UART is a hardware form of the RS-232 protocol. Am I correct?


The termial say's package google-chrome-stable needs to be reinstalled but can't find it in the archives. What do I need to do? I keep getting errors.

How do you install Google Chrome on Ubuntu?


Fred and George seem to have created a wide range of gag gifts and practical joke items, both while at Hogwarts and then as owners of their "Wizard Wheezes" emporium.   What are all the known "jokes items" that Fred & George created throughout HP History and what were their side-effects?

Fred and George Weasley are known for their trouble-making and general "solemnly swearing they are up to no good". Their antics/adventures give something to smile about and show us not all wizards are as serious as Professor McGonagall and Hermione. This gives them a reputation of being less intelligent and indeed they only achieved three OWLs. However, we also see the twins have quite a brilliant side! Being able to open and successfully run a shop in Diagon Alley without having completed their Hogwarts education is no easy take (IMO, anyway). Their creations helped students get out of class, our heroes out of tight spot, and even stop our enemies execute an evil plot. Ginny may have said it best:  "We’ve been hearing explosions out of their room for ages, but we never thought they were actually making things," said Ginny. "We thought they just liked the noise." Harry Potter and the Goblet of Fire  Do we know how many things Fred and George invented?


I was making a table of the sentence "You must/have to see it." ("You see it.") in different tenses and moods in German with the English equivalent.  I ended up writing these three sentences down (in English) and was unsure about what tense they were in or if they could be considered valid sentences.     (1) You will have had to see it.   (2) You will have to have seen it.   (3) You will have had to have seen it.     I believe that (1) is future perfect but I have no idea about (2) and (3).  Thanks!  ==================================================================  I'm a native English speaker and so I have never had a formal teaching of English grammar. As an example I will have used future perfect many times in my life but I have only recently known of it's existence! Most of what I have learnt is from the perspective of learning German.

Do we have 16 tenses in English?  With   future present past future in the past   in these forms   simple continuous perfect perfect continuous   Can we manipulate these together to create English tenses? For example, "present perfect" or "future perfect continuous"?


I'm having a hard time to parse this PHP to JSON kan someone help me with this how can I convert this PHP into JSON  $query = "SELECT SUM(total)  FROM account"; $result = mysql_query($query);  while($row = mysql_fetch_assoc($result)) { echo $row['SUM(total)']; }

How do I use the json_encode() function with MySQL query results? Do I need to iterate through the rows or can I just apply it to the entire results object?


I've been wondering, is there any link between each LoZ game other than there's a character called Link who has to save Zelda? Because it seems that most of the time it's a different setting like at sea or on land or in the sky. Could it be parallel universes? Different time zones?  Are there any canon facts or any fan theories that put it to rest?

In the various Zelda video games, there seems to be a common mythology, and at least some potential to be in the same place. Do the various Zelda games take place in the same world, or is there no intent to do so?


I can't solve NullPointerException problem (82 line). It's simple code with interface. In final result it have to print 10 random shapes with its parameters and total area of shapes. Final result should look like in picture.

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


Is it considered poor practice to m/calloc without casting it to the type of the pointer? For example: MyType *binary = calloc(1, sizeof(MyType));  vs: MyType *binary = (MyType*) calloc(1, sizeof(MyType));  I don't ask this as an opinion-question, but more than I am a beginner in C and wondering if the first method has disadvantages compared to the second one -- as if they're the same, the first version seems a bit friendlier to type out.

In , someone suggested in a  that I should not cast the result of malloc. i.e., I should do this: int *sieve = malloc(sizeof(int) * length);  rather than: int *sieve = (int *) malloc(sizeof(int) * length);  Why would this be the case?


I am doing seo for my website, I am facing a strange problem while i optimize my website.  My site is indexed in google but not showing for my keyword. I searched first 100 pages in google,but my website is not appearing for the keyword.Google is not considering my company has a webdesigning company. Not only this keyword. i can't get my website in google search result for any keyword.  The keyword i am targeting is “web designing company in MY CITY” I will list out all the things i have done so far.   The key word is present in  tag. Keyword is present in meta keyword and meta description. Keyword is also present in the home page for 4 times. Added my site in webmaster tools. Site map Submitted and No crawl errors. Added my website in google analytics. Created a G+ page and its verified. keyword is present in G+ page description. 5 reviews in G+ page. All are 5 Star Reviews. Added my address in Structured data in webmaster tools. I believe that my site is providing relevant content to users regarding web design services. Added G+ badge to website. According to MOZ open Site explorer. 9 Domains Pointing to my website, 84 links have my website in their page. Domain authority is 16 and Page Authority is 29. Marked has a local business Google map has my Location.   Recently i posted a new blog in my website.Google showed the blog in first page for few hours but now its not showing the result. I searched this again in first 100 pages.  Overall Google is not recognizing my company has a Web Designing company. If i search web designing company i can see all other companies listed but not mine.  I get lots of spam traffic in google analytic.  My domain ranking is varying in many places.  Moz Open site explorer - Domain Authority 16 Ahrefs Site Explorer - Domain Authority 48  I don't know why this is happening. Did i missed anything? Can anyone please help me where i am doing wrong?

What are the best ways to improve a site's position in the Google search results?


For some reason my ubuntu-software-center disappeared (on Ubuntu 18.04).  I tried the usual   sudo apt-get update   and   sudo apt-get install software-center   But I end up with this error:  Package software-center is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source  E: Package 'software-center' has no installation candidate   How can I solve this issue? I tried with synaptic but it did not work out.

I'm using Ubuntu 18.04.2.  I cannot find Ubuntu Software (or Software center) in my dash. I have tried to install it with the following commands:  sudo apt-get update sudo apt-get upgrade   then   sudo apt-get install software-center*   After all the processes have run I get the following message:  $ sudo apt-get install software-center Reading package lists... Done Building dependency tree        Reading state information... Done Package software-center is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source  E: Package 'software-center' has no installation candidate   I think the problem might be related to my earlier attempt to install the MATE desktop environment. Since it failed I purged the installed packages. I assume that when I purged MATE packages I also deleted the software center and something that is needed its re-installation.


Question "Submit the assignment by February 10th." What does this statement mean? Possibility 1 The assignment should be submitted by February 10th, 23:59. Possibility 2 The assignment should be submitted by February 9th, 23:59.

I have read the Rules of a competition. The text of the Rules include a sentence as follows:     As per stated in the Rules the entrants will be notified by May 30th 2010.   Does the sentence above mean that May 30th is included in the term of notification or not?


I am trying to find out when for creating classification rule to use linear discriminant function and when to use logistic regression? I need to help to find information sources to this topic. Any clue?

I am trying to wrap my head around the statistical difference between Linear discriminant analysis and Logistic regression. Is my understanding right that, for a two class classification problem, LDA predicts two normal density functions (one for each class) that creates a linear boundary where they intersect, whereas logistic regression only predicts the log-odd function between the two classes, which creates a boundary but does not assume density functions for each class?


When I make a end portal in minecraft XboxOne Edition Winter Upate it doesnt work all of then are facing in lava and everything so I decided to go to a stronghold but I didnt know how to get to one. So i'd like to know how! :-)

I've been searching for hours in the game to find a Stronghold and haven't seen one. Apparently lots of mobs and treasures can be found there, but the question is where can we find those?  Can we find them near a ravine or abandoned tunnels?


Weight is a force. Force is mass × acceleration.   When I'm standing motionless on the scale, how do I have a weight greater than $0~\mathrm{N}$ when my mass is $90~\mathrm{kg}$ and my acceleration is $0$? $90~\mathrm{kg}$ × $0~\mathrm{m/s^2}$ = $0~\mathrm{N}$  EDIT:  Thanks, @Inquisitive for showing me that the acceleration component of force need not be explicit and allowing me to understand this concept of weight logically and mathematically.  I weigh 200lbs. 9.8m/s^2 is 32.152ft/s^2. 200lbs ÷ 32.152 =  6.22slugs (about 90kg). 90kg × 9.8m/s^2 = 882N (about 200lbs)  My explicit acceleration of 0 is irrelevant to this equation. The magnitude of gravitational acceleration is the correct acceleration to use in this figure. The word "acceleration" caused the misconception that something would be visually observable, namely movement.

I know this question has been asked in other forms, generally regarding the balance of forces.  This time I want to focus on motion.  I've got a laser accelerometer on my desk.  It tells me that I'm accelerating at $9.8~\rm m/s^2$.  For the first experiment I'm travelling in space.  I pick a nearby star and discover that I move about $490$ meters in $10$ seconds from that star.  For the next experiment I'm on the surface of Earth.  I measure the same acceleration with my laser accelerometer.  I pick a spot (the center of the Earth) and discover I don't move at all in $10$ seconds.  How is acceleration without motion possible?


We say that a positive integer is full of squares,if in its factorization all the primes appear raised to an exponent greater than one. For example, $72 = 2^3⋅3^2$ is full of squares and $18 = 2⋅3^2$ is not. Prove that there exist infinite positive integers $n$ such that $n$ and $n + 1$ are filled with squares.   The only thing I think that I figured out is that the solution uses induction.

One way to prove that there is an infinity of consecutive powerful integers is to just note that there are infinite solutions to the equation $x^2-8y^2=1$, because clearly $x^2$ and $8y^2$ are clearly powerful. But this uses a bit of theory.  I found this problem under an induction worksheet, and all of the surrounding problems are easy. Is there really an elementary solution to the problem?  All of my attempts have been fruitless.  Note: a number is powerful if whenever a prime $p$ divides it we have that $p^2$ also divides it.


On one of my pages, I have a text area html tag for users to write a letter in.  I want the content below the text area to shift down, or in other words, I want the text area to resize vertically with each line added to the text area and to have the content below simply be positioned in relation to the bottom of the text area.  What I am hoping is that javascript/jquery has a way to detect when the words wrap, or when a new line is added and based on that do a resize of the text area container.  My goal is to make the content below the text area stay the same distance from the bottom of the text no matter how much a user writes.  The text area creates a scroll bar when the text overflows.

There was , which I've tried. But there is one problem: the textarea doesn't shrink if you delete the content. I can't find any way to shrink it to the correct size - the clientHeight value comes back as the full size of the textarea, not its contents.  The code from that page is below:  function FitToContent(id, maxHeight) {    var text = id && id.style ? id : document.getElementById(id);    if ( !text )       return;     var adjustedHeight = text.clientHeight;    if ( !maxHeight || maxHeight > adjustedHeight )    {       adjustedHeight = Math.max(text.scrollHeight, adjustedHeight);       if ( maxHeight )          adjustedHeight = Math.min(maxHeight, adjustedHeight);       if ( adjustedHeight > text.clientHeight )          text.style.height = adjustedHeight + "px";    } }  window.onload = function() {     document.getElementById("ta").onkeyup = function() {       FitToContent( this, 500 )     }; }


Let there be two bodies a and b. Let a be on Earth and b in space with velocity $(√3/2)c$. Then let the time interval which has passed (on the earth) be twice that of the time interval of which passed in space for b, (i.e. the time for b is dilated for body a).  Does b also feel that the time interval which it passed with a spaceship in space is twice that of the time interval of a which passed on the earth? I ask this because for b relative to it, a is also moving with velocity $(√3/2)c$.

I read a lot about the classical twin paradox recently. What confuses me is that some authors claim that it can be resolved within , others say that you need . Now, what is true (and why)?


I just bought my very first internal SSD and installed it into my desktop PC. I was running out of disk space and want to use it for data storage. The OS is installed on the first disk, which is a standard (spinning) HDD. This is what Samsung Magician is showing me:    So "on paper", everything seems to look great. However, when I'm trying to move files from my HDD to the SSD, I'm only getting about 50-70 MB/s. I assumed that the bottleneck here is the speed limit of the HDD read access... What I don't understand is why this bogs down my whole system. I would expect Windows 7 to be smart enough not to allow itself freeze up during simple file transfer operations. Also, the PC has 32 GB RAM and a 3,4 GHz 12-core CPU, so it's not exactly slow. What might be the problem here? The system gets so slow that I cannot even open Firefox while moving files. Shouldn't the system somehow manage the amount of resources processes can take and put a cap on it in order to ensure stability? Is there some setting that I could change to address the issue? Unfortunately, I have little to no experience managing Windows systems. I know that in Linux one can impose custom limits on the resource usage of individual processes. However, file I/O seems something rather fundamental so I'd expect this to be efficiently managed by the OS. Please help, the setup is not usable in this state... PS.: I don't want to migrate the system to the SSD as I don't trust Windows with my data. The data should be stored on a separate drive, which is why I got the SSD in the first place. But this should not slow down my system on the HDD.


I have about 6 months novice experience in SQL, TSQL, SSIS, ETL.  As I find myself using JOIN statements more and more in my intern project I have been experimenting with the different JOIN statements.  I wanted to confirm my findings.  Are the following statements accurate pertaining to the conclusion of JOIN statements in SQL Server?:  1)I did a LEFT OUTER JOIN query and did the same query using JOIN which yielded the same results; are all JOIN statements LEFT OUTER associated in SQL Server?  2)I did a LEFT OUTER JOIN WHERE 2nd table PK (joined to) IS NOT NULL and did the same query using an INNER JOIN which yielded the same results; is it safe to say the the INNER JOIN statement will yield only matched records? and is the same as LEFT OUTER JOIN where joined records IS NOT NULL ?  The reason I'm asking is because I have been only using LEFT OUTER JOINS because that is what I was comfortable with.  However, I want to eliminate as much code as possible when writing queries to be more efficient.  I just wanted to make sure my observations are correct.  Also, are there any tips that you could provide on easily figuring out which JOIN statement is appropriate for specific queries?  For instance, what JOIN would you use if you wanted to yield non-matching records?  Thanks.

Also how do LEFT JOIN, RIGHT JOIN and FULL JOIN fit in?


How do I force the shell I called a script from to reload .bashrc from inside the script?  I'm trying to make a "new box" script that sets everything up the way I like it. Everything works, except for reloading .bashrc.   I know I can "just" do . ~/.bashrc or exec bash or any of the other ways to apply changes after running the script. But it kind of defeats the purpose of making a one-button fix, and coming this far just to get screwed on the last step is driving me nuts lol    I've tried adding all of the source ~./bashrc exec bash stuff to the script, but no joy since it is only reloading it for the script's environment, not the calling shell  I'm still fairly new so it's probably something super obvious which would explain why I couldn't googlefu the answer >.<  any help would be much appreciated.

I am setting my JAVA_HOME in my ~/.bashrc file.  Now, I need to create a script that will change the JAVA_HOME just for the current terminal, so that I can start an app that needs java 5.  I have created this script to do this task, but after finishing, I can see that JAVA_HOME is not updated  export JAVA_HOME=/usr/lib/jvm/java-5-oracle/ export PATH=$PATH:$JAVA_HOME       Here is the result  $ ./javaHome5.sh $ echo $JAVA_HOME /usr/lib/jvm/java-6-oracle/   I think that the reason this is not being applied, is that a script is executing in it's own terminal, so when the script ends, the current terminal will not be affected.  Currently, the only way I've found around this is:   Edit my ~/.bashrc and change the JAVA_HOME var Run source ~/.bashrc to apply the changes in current terminal. Which again cannot be applied in a script, as the source command needs to be run in the current window.   Needless to say, this change applies to all new terminal windows, so I practically need to do this twice: One before starting my app, and one more time right after this, just to restore the environment vars to their default. That's not really convenient.  Do you have any ideas how can I change this var using a script?


Here's a proposal that emerged from :  People seem to love to vote to close, and the fact is that existing close votes tend to encourage more.    To avoid systematic bias toward closing questions, I would like to propose that the number of pending close votes not be displayed unless the user has clicked close (or taken a similar action).  There is really no reason to make the number of close votes on a question so obvious.    All it does is encourage users to close the question, which is:   Useless for poor questions (because they would've been closed anyway) Counterpoductive for good questions ...since a user who would not have otherwise thought of closing the question is now explicitly encouraged to vote to close: it's basically saying, "others think this question sucks; do you agree?"   The same should probably be done for delete.    However, I think reopen should still display the number of required votes, because it will encourage users to read questions that may have been improved and vote to re-open them. We're not really having problems with too many undeserving questions getting re-opened, so it should stay as-is.  Thoughts?

I don't see why users (even those with high rep) should be able to see the number of close-votes for any questions they did not post. I've observed that the mere presence of a close vote can trigger more, and -- quite often -- this biases things in favor of the person who cast the first vote, which makes all the difference in edge cases.  Mind you, it affects me just as much as anybody -- there have definitely been some cases where I would not have voted had I not seen that others were closing a question. I try my best, of course, but we're all human...  The only exception, in my opinion, is when closing as a duplicate. But even then, it doesn't matter how many votes there are -- instead, the site can simply put the top-suggested votes at the top of the list, without mentioning which ones were chosen by people and which ones weren't.  So really, I don't see why the number of close votes should be visible to anyone other than the OP -- and so I'm proposing we remove the display of pending close votes for anyone who doesn't need to see it.


I purchased HTC One X unlocked (with AT&T) with Android ICS. I am using this phone in India with Airtel SIM.  How can I upgrade the device to Jelly Bean?

This Community Wiki question is designed to be the "canonical question" for questions asking how to upgrade one's device to a new Android version.   I want to get a newer version of the OS for my Android device. How can I do that?  See also:


The expression "It's all up hill from here!" and "It's all down hill from here!" mean that things will only get better or things will only get worst.  Metaphorically going uphill can provide for a better position, while going down hill is easier.  Which expression represents which way?

The phrase "it was all downhill from there" seems to have two, contradictory meanings.  The first indicates that things have since gotten a lot worse. For example (from ):      After a promising first half against the Philadelphia Eagles in Week 1 in which they jumped out to a 17-0 lead, it has been all downhill from there. They lost that game 34-17 and lost their next three games by a combined score of 118-41.   While the second means the opposite thing--that the hard part is over and it's all smooth sailing now. For example (from ):     September 10. That's the official peak of hurricane season for the Atlantic Basin. It's all downhill from here to the end of the season, November 30.   I pretty much exclusively use the phrase for the latter meaning, since to me that's more intuitive. If everything is "downhill" now, you don't have to pedal any more or work as hard to get to the bottom.  Can anyone elaborate on the origin of the phrase, what "downhill" is specifically referring to, the accepted usage, or if there are subtle differences in the way one is supposed to phrase the two different meanings?


What is the recommended minimum CPU, disk space and memory (RAM) requirements of Ubuntu 64 and 32 bit 14.04 LTS?

I'm thinking about installing Ubuntu Desktop, but I don't know what flavor is the best for my system. What are the minimum and recommended hardware requirements? What kind of CPU? How much memory? Should I have Hardware Acceleration? What flavor should I use?  This is an attempt of a canonical answer. My answers have the "official  requirements", the recommended are a mix of official sources and opinion based (along with the answer it's told the source). You can comment or edit if you feel that the information is obsolete or incomplete. It is a good rule of thumb that any system capable of running Windows Vista, 7, 8, x86 (Intel) OS X will almost always be a lot faster with any Ubuntu flavor even if they are lower-spec than described below.


I need help Proving this: "For Every $n\in \mathbb{N-{0}}$ Prove the following: $$\sin(1)+\sin(2)+...+\sin(n)=\frac{\sin(\frac{n+1}{2})\sin(\frac{n}{2})}{\sin(\frac{1}{2})}"$$ I assume we have to use Induction On this but I failed to do so If anyone can provide a simple and clear proof I would be grateful!

How can we sum up $\sin$ and $\cos$ series when the angles are in arithmetic progression? For example here is the sum of $\cos$ series:  $$\sum_{k=0}^{n-1}\cos (a+k \cdot d) =\frac{\sin(n \times \frac{d}{2})}{\sin ( \frac{d}{2} )} \times \cos \biggl( \frac{ 2 a + (n-1)\cdot d}{2}\biggr)$$  There is a slight difference in case of $\sin$, which is: $$\sum_{k=0}^{n-1}\sin (a+k \cdot d) =\frac{\sin(n \times \frac{d}{2})}{\sin ( \frac{d}{2} )} \times \sin\biggl( \frac{2  a + (n-1)\cdot d}{2}\biggr)$$   How do we prove the above two identities?


I know what reflection does, but I want to know in what exact case that we can use it. Like, using reflection we can come to know whether the class contains the specified method or not. I also want to know the actual scenario where this kind of requirements can come in picture? and does the use of reflection have any impact on application performance?

Does creating an object using reflection rather than calling the class constructor result in any significant performance differences?


Read in the late 1980s, this was a sci-fi novel about an alien invasion which quickly overpowered all opposition globally. The protagonist was a trusted go-between between humans and the invaders who eventually turned against his alien masters. He stole alien anti-gravity technology and used it to spray paint massive graffiti on public monuments e.g., Big Ben in London from memory. I seem to recall the graffiti was of a monk in a habit which may have been what the main character wore when completing his protests. Whilst the aliens were massively technically superior, I think in the end they left as they were unable to comprehend how anyone could or would betray them

I have been trying to recall the title of a book I read about 25 years ago (1987), I have tried to find it again a couple of times over the years without any luck.    The story takes place on earth, which has been invaded and conquered by aliens.  The humans have become servants or slaves.  One of the primary human characters is the human servant of an alien leader.  If I remember correctly, the aliens are much bigger than humans, I keep thinking of horses or elephants for some reason with regard to the aliens.  At the end, somehow the human slaves have forced the aliens to abandon their conquest of earth, but I don't remember exactly why.  I think it was something to do with simply refusing to be obedient, which the aliens could not comprehend, but I'm not sure about that.  I think the book ends with the alien leader (and the rest of the aliens) blasting off from earth in a rocket.  Does anyone recognize what book I'm referring to?  Thanks for any help!


I have a vague recollection of a time travel TV movie from the '90s, where the villain is seen in a variety of black and white photos, and is following a group of people through time. The antagonist/time traveller is a somewhat known actor in this style of movie, and looks somewhat similar looking to the modern Marvel character "Loki", with a white complexion and slicked back, black hair (but at the time he was quite a bit older). It was a C or D-list movie that played regularly, and I'm fairly certain "time" was in the title.

I saw a film about 10 years ago. It was about people that could live the biggest disasters in the world that had happened again. They could travel in time and see these disasters. There were some plane crashes, metro crashes, Titanic disaster and so on.  But one man (positive main role) saw another bad man who was throwing a coin in the air and this coin fell down. This positive role changed a destiny and saved many people. This saving caused some damages to negative roles in this film.


I remember when I was on my Windows 8 laptop, I could press my sprint key, which is Caps Lock (don't judge) and I could hold it while I jump, but on my new Windows 10 computer, I can't hold my sprint key and jump. Are there any suggestions to fix this please?

Ok, so I do a lot of sprint jumping in minecraft because I pvp a ton everyday and every once in a while it won't allow me to do both at the same time. I set ctrl to my sprint key so when I want to sprint I hold ctrl. If I hold ctrl and space it won't let me jump. If I double tap w I can sprint and jump at the same time. Does anybody know why it does this? It's not something to do with my keyboard because it's just fine. It's done this a couple of times and it's quite annoying.


I have read that contra-variant and co-variat vectors have different transformation properties , which distinguish them, yet at the same time I have read that a vector can have contra-variant and co-variant components. If a vector can have contra-variant and co-variant components, then isn't this vector both contra-variant and co-variant? But isn't this impossible?

I am looking at the 4-vector treatment of special relativity, but I have had no formal training in Tensor algebra and thus am having difficulty understanding some of the concepts which appear.  One such concept is the notion of contra- and co-variant vectors.  describes a contra-variant vector as varying with the co-ordinates, i.e. the inverse of the reference axes. It gives the example of a change of basis matrix $\mathbf{M}$, and a contra-variant vector $\vec{v}$ and states that in the new set of co-ordinates, we have:  $$\vec{v}'=\mathbf{M}\vec{v}$$  It then states that a covariant vector varies with the co-ordinate axes.     Does this mean that for a covariant vector $\vec{u}$ and change of basis matrix $\mathbf{M}$ we have: $$\vec{u}'=\mathbf{M}^{-1}\vec{u}?$$   I am also having problems understanding the concept of raising and lowering indices. For instance, Wikipedia states that for two four-vectors $\vec{A},\vec{B}$ and using Einstein summation we have:  $$\left\langle \vec{A} \middle|\vec{B} \right\rangle=A^{\mu}B_{\mu}=A_{\nu}B^{\nu}$$  And I am having difficulty understanding how this relates to the other definition of the inner product:  $$\left\langle \vec{A} \middle|\vec{B} \right\rangle =\mathbf{A}^{T}\mathbf{\eta}\mathbf{B}$$  If anyone could help give me a more intuitive understanding of these concepts I would be grateful.


I don't know what to do, please help      'E/AndroidRuntime: FATAL EXCEPTION: main                     Process: com.is2all.so2al_ijaba, PID: 13051                     java.lang.RuntimeException: Unable to resume activity {com.is2all.so2al_ijaba/com.is2all.so2al_ijaba.windows_asila}: java.lang.NullPointerException: Attempt to invoke interface method 'int java.util.List.size()' on a null object reference                         at android.app.ActivityThread.performResumeActivity(ActivityThread.java:3103)                         at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:3134)                         at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2481)                         at android.app.ActivityThread.-wrap11(ActivityThread.java)                         at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)                         at android.os.Handler.dispatchMessage(Handler.java:102)                         at android.os.Looper.loop(Looper.java:148)                         at android.app.ActivityThread.main(ActivityThread.java:5417)                         at java.lang.reflect.Method.invoke(Native Method)                         at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)                         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)                      Caused by: java.lang.NullPointerException: Attempt to invoke interface method 'int java.util.List.size()' on a null object reference                         at com.is2all.so2al_ijaba.windows_asila.table(windows_asila.java:204)                         at com.is2all.so2al_ijaba.windows_asila.onResume(windows_asila.java:439)                         at android.app.Instrumentation.callActivityOnResume(Instrumentation.java:1258)                         at android.app.Activity.performResume(Activity.java:6312)                         at android.app.ActivityThread.performResumeActivity(ActivityThread.java:3092)'   the code :  public void table() {          handler.removeCallbacks(run);         count=30 ;         rnd = rand.nextInt(mDataList.size());         id = mDataList.get(rnd).ID ;         btn.setText(mDataList.get(rnd).Question);         btn2.setText(mDataList.get(rnd).Answer_1);         btn3.setText(mDataList.get(rnd).Answer_2);         btn4.setText(mDataList.get(rnd).Answer_3);         btn5.setText(mDataList.get(rnd).Answer_4);         count_b = mDataList.get(rnd).ID_answer;         timer();         if (mInterstitialAd.isLoaded() & rnd == 2 || rnd == 4 || rnd == 8 || rnd ==16 || rnd == 32 || rnd == 64 || rnd == 128 ) {             handler.removeCallbacks(run);             mInterstitialAd.show();         } }      @Override     protected void onResume() {         super.onResume();         table();          SharedPreferences savechange =  this.getSharedPreferences             ("savechange", Context.MODE_PRIVATE);         int Point = savechange.getInt("Point",point);         this.point = Point;         btn7.setText("+نقط : "+point);     }

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


Let $f:\mathbb{C}\to \mathbb{C}$ be an entire function, and suppose that for every $z\in \mathbb{C}$ there exists $n_z\in \mathbb{N}$ such that $f^{(n_z)}(z)=0$.  Is $f$ necessarily a polynomial?

Let $f:\mathbb{C}\rightarrow\mathbb{C}$ be an entire function. And assume that at each point, one of it's derivatives vanishes.  What can you say about $f$?  A hint suggests that $f$ must be a polynomial.


I will be traveling to UK on work visa (Tier 2 - Intra company transfer). Of course, i will also be holding my India passport.  Will I be allowed to travel to Dublin, Republic of Ireland based on Tier 2 Work visa? I meant without the extra effort for applying for separate Irish visa?

Do immigration checks exist between Northern Ireland and England/Scotland? (not just for flights but also ferry/bus/train) Do immigration checks exist between the Republic of Ireland and England/Scotland?


If $V_0$ is the subspace consisting of matrices of the form $C=AB-BA$ for some $A,B$ in a vector space $V$ then $V_0=\{A\in V|\operatorname{Trace}(A)=0\}$.  The problem above is one of the past qualifying exam problems. I can prove that  $V_0\subset\{A\in V|\operatorname{Trace}(A)=0\}$ but I do not know what to do with converse.  Thank you in advance.

This is the fourth part of a four-part problem in Charles W. Curtis's book entitled Linear Algebra, An Introductory Approach (p. 216).  I've succeeded in proving the first three parts, but the most interesting part of the problem eludes me.  Part (a) requires the reader to prove that $\operatorname{Tr}{(AB)} = \operatorname{Tr}{(BA)}$, which I was able to show by writing out each side of the equation using sigma notation.  Part (b) asks the reader to use part (a) to show that similar matrices have the same trace.  If $A$ and $B$ are similar, then  $\operatorname{Tr}{(A)} = \operatorname{Tr}{(S^{-1}BS)}$  $= \operatorname{Tr}(BSS^{-1})$  $= \operatorname{Tr}(B)$,  which completes part (b).  Part (c) asks the reader to show that the vector subspace of matrices with trace equal to zero have dimension $n^2 - 1$.  Curtis provides the hint that the map from $M_n(F)$ to $F$ is a linear transformation.  From this, I used the theorem that $\dim T(V) + \dim n(T) = \dim V$ to obtain the dimension of the null space.  Part (d), however, I'm stuck on.  It asks the reader to show that subspace described in part (c) is generated by matrices of the form $AB - BA$, where $A$ and $B$ are arbitrary $n \times n$ matrices.  I tried to form a basis for the subspace, but wasn't really sure what it would look like since an $n \times n$ matrix has $n^2$ entries in it, but the basis would need $n^2 - 1$ matrixes.  I also tried to think of a linear transformation whose image would have the form of $AB - BA$, but this also didn't help me.  I'm kind of stuck...  Many thanks in advance!


I'm trying to find a replacement solution for a large university's current web presence.  There are a number of strategies we are considering, including perhaps using an open-source or commercial off-the-shelf software solution.  The list of requirements we have is very lengthy, but main points include:   Robust content management system, which would allow for creation of multiple independent sections on the site, Flexible permissions system, allowing for a large number of section-specific administrators and editors, Ease of use, Extensibility, allowing us to integrate the software with existing IT resources (e.g. LDAP-controlled login system, numerous databases with HTTP interfaces, etc.)   If anyone here worked or studied at a university and has used or implemented software solutions to this problem, I would be very keen to hear your opinions of what works well or what doesn't.

This is a general, community wiki  question to address non-specific "I need a CMS or Wiki that does x, y, and z..." questions.  If your question was closed as a duplicate of this question and you feel that the information provided here does not provide a sufficient answer, please open a discussion on .    I have a list of features that I want for my website's Content Management System (CMS) - where can I find a [free] script that includes all of them?


When I click a file (or selection of files) in nautilus (Files) and start a drag, only the selection rectangle happens - the files stay put.  As seen here - I expect the file to move but instead others are selected.

I'm having a strange problem on Ubuntu 17.10: when I try to drag and drop something inside Nautilus it simply doesn't work, it doesn't even select the item, it seems like it's ignoring the action... Also, I cannot select things inside nautilus by drawing rectangles with the mouse.  All of these actions work only on the Desktop. Here is a demo:    I'm using the Xorg session with nVidia proprietary drivers. I also noticed that Nautilus seems to hang when I try to copy, paste or cut a file...  EDIT 1: I solved the problem for the slow copy/paste by disabling the clipboard sync plugin of KDEConnect. I also discovered that if I open Nautilus as root, I can drag and drop or select whatever I want...


I am currently applying for graduate school in France. How (if at all) would I modify my existing CV in the standard US format to conform to French academic standards?  I have searched online, but most results are comparing a standard US resume to a European CV.

I find it irrelevant to specify personal information on my CV, and frankly I do not see why they should be listed in academic applications. What is the advantage for the hiring committing to know if I am 18 or I have 17 children, aside from creating a chance to bias the hiring process with personal beliefs. Is it because they want to know that I am a prodigy child who got his/her PhD at 18 years old, or because if I am a 28 years old female married without children I will want children soon and so I will have to take maternity leave? Is this just an influence of the age/status discrimination in Europe where I see at times that  job offers are only open to certain categories of people (i.e.,younger than 30 years old) ?  If I omit this information will my CV be frowned upon? Or will they think I am hiding something? I do not know what I would be hiding because age can probably be guessed from the CV anyway.


This is an odd question, but I was wondering if there is an English formal word connoting the same concept that the word "badass" conveys. To be exact, I mean "badass" as in someone who is maybe arrogant, morally bad, wicked, perhaps disrespectful, yet, at the same time, secretly admired for his energy, over-confidence, taking the lead, conquering qualities, etc.    Thank you.

Badass and BAMF are both modern words with approximately the same meaning: "Someone who is awesome to an extreme level, thereby leveraging unquestionable authority." Is there another noun or title that would convey the same level of awe, admiration and toughness that calling someone a badass does, without the vulgarity?  Thanks for any help. :)


how do I go about including a hyperlink in the bibliography.  I am trying this and it does not work:  @article{pll_wikipedia,     address = {http://en.wikipedia.org/wiki/Phase-locked\_loop},     publisher = {Publisher},     author = {},     title = {Phase-Locked Loop},     year = {},     volume = {},     number = {},     pages = {},     month = {} }

I would like to cite articles and the specific authors from well known websites. My problem is that I would also like to include the website info in the citation. For example I am citing an article from Surfing Magazine but the article was only published online and not in the magazine. Alternatively, I am looking to cite an article from surfline.com by a named author but I would like surfline.com to show up in the citation alone and not just included in the url portion of the citation.   My code is as follows:  For the online references I used the following format in my .bib file (Cite.bib)   @MISC{maldives,    author =       "Connoly, Darlene",    title =        "Controversy in the Maldives",    editor =       "Surfline.com",    month =        "August",    year =         "2012",    url =          "\url{http://www.surfline.com/surf-news/maldives-surf-access-controversy-update_75296/ }",    note =         "[Online; posted 27-August-2012]",  }   @MISC{mull,    author =       "Mull, Jeff",    title =        "Maldives Controversy",    editor =       "Surfing Magazine",    month =        "September",    year =         "2010",    url =          "\url{http://www.surfermag.com/features/maldives-controversy/ }",    note =         "[Online; posted 13-September-2012]",  }   For the .tex file I am using the following code/packages   \usepackage{natbib}  \usepackage{url}   \begin{document}    text   \nocite{mull}  \bibliographystyle{plainnat}  \bibliography{Cite}   \end{document}   When I try to compile the document using 'pdftexify' I get the following error.  Package natbib warning: Citation 'Mull' undefined on input line 373   [23] [24] [25] (C:\Users\...\LaTex\title.bbl ! TeX capacity exceeded, sorry [input stack size=5000]. \@makeother #1->\catcode '#1                         12\relax 1.12 ...  ! ==> Fatal error occured, no output PDF file produced! Transcript written on title.log. texify: pdflatex.exe failed for some reason (see log file)   However if I try the same syntax using an @ARTICLE or @BOOK reference from 'Cite.bib,' I do not get the error. I am looking for a way to cite authors of online articles as well as the website they were published on. Any help with this will be really helpful.   Also, if it is not important or not regularly practiced to include the name of the website separately in the citation then I could just omit the editor portion of my @MISC entries. I have tried omitting the editor field but I still get the same error message.


Say I need to build n lambda functions, and put them into a list:  n = 6 lamd_list = [lambda x: x * i for i in range(n)]   Here x is input of the lambda functions, and the i is intended to be fixed to 0~5 in the list. However, when I run:  lamb_list[0](3)   The output would be 15 (3 * 5) instead of 0 (0 * 5). How can I modify the code to make it do as I intended? Note that here the n is a variable (not fixed), so I can't do the loop manually. Also, I don't want i as an input to the lambda function.

I want to create a list of lambda objects from a list of constants in Python; for instance:  listOfNumbers = [1,2,3,4,5] square = lambda x: x * x listOfLambdas = [lambda: square(i) for i in listOfNumbers]   This will create a list of lambda objects, however, when I run them:  for f in listOfLambdas:     print f(),   I would expect that it would print  1 4 9 16 25   Instead, it prints:  25 25 25 25 25   It seems as though the lambdas have all been given the wrong parameter. Have I done something wrong, and is there a way to fix it? I'm in Python 2.4 I think.  EDIT: a bit more of trying things and such came up with this:  listOfLambdas = [] for num in listOfNumbers:     action = lambda: square(num)     listOfLambdas.append(action)     print action()   Prints the expected squares from 1 to 25, but then using the earlier print statement:  for f in listOfLambdas:     print f(),   still gives me all 25s. How did the existing lambda objects change between those two print calls?  Related question:


I have a daily time series and when trying to check for normality I am getting the QQ plot below. Any ideas as to what is the plot saying about my data?

I am working with a small dataset (21 observations) and have the following normal QQ plot in R:     Seeing that the plot does not support normality, what could I infer about the underlying distribution? It seems to me that a distribution more skewed to the right would be a better fit, is that right? Also, what other conclusions can we draw from the data?


Just switched from maya to blender and as you can assume, I'm having some troubles. I can figure out the program just fine, but I want to know the reason why the render camera is designed with such navigation restrictions? Why not give it the same movability as the viewport? And is there a way I can change this?

One of the things I haven't learned about using Blender is how look from a camera and use the exact same commands to pan, rotate and zoom with the camera as I do with the viewport. I'm used to doing this with either C4D, Maya, Modo, Max, etc... but in Blender It feels like a different workflow for those who are coming from other 3D applications. Is there anything that can be done about this either in the settings or through an addon?


How can I concatenate or merge 2 or more MP4 files, in a final output MP4 file also?  I have tried in the DOS window to use the COPY command (I have read it somewhere) but it doesn't function well.

I have two high-quality mp4 files, which are of two parts of the same show.  I want to merge them together into 1 file, and I usually use VirtualDub to merge my files... But it doesn't seem to support mp4.  What alternatives are available (especially ones that don't require re-encoding)?