Why did financial institutions added chip to credit, debit cards while they already had magnetic strip? Is there different kind of information stored on both and how is chip card with magnetic strip more secure than just magnetic strip card?
The new Chip credit cards are being introduced to provide better security to consumers, merchants and credit card vendors.    Sample Card:   (source: )    Card Reader &amp; PIN Entry:    Are they really better from a security point of view?  What are the advantages and disadvantages?
How to setup Java-Home and Path in Ubuntu 12.04 Is your MAC address revealed when you hit up a website? How to draw Venn diagrams (especially: complements) in LaTeX What I am up to is to write some exercises dealing with logical formulas for my students, like:     And the students should draw these formulas on . At the end of the lesson, I really would like to print the correct answer for them. I found a great resource on a forum thread at , which helped me a lot to make up some Venn diagrams with tikz, but have some problems with visualizing complements, like ~A.  A simple, modified version of the TeX file found on the forum linked above, can be seen below, which produces the following expression:    \documentclass{letter}   \usepackage{tikz}   \def\firstcircle{(90:1.75cm) circle (2.5cm)}   \def\secondcircle{(210:1.75cm) circle (2.5cm)}   \def\thirdcircle{(330:1.75cm) circle (2.5cm)}   \begin{document}     \begin{tikzpicture}       \begin{scope}     \clip \secondcircle;     \fill[cyan] \thirdcircle;       \end{scope}       \begin{scope}     \clip \firstcircle;     \fill[cyan] \thirdcircle;       \end{scope}       \draw \firstcircle node[text=black,above] {$A$};       \draw \secondcircle node [text=black,below left] {$B$};       \draw \thirdcircle node [text=black,below right] {$C$};     \end{tikzpicture}   \end{document}   Which looks like:    Could anyone please help me out plotting/defining some expressions dealing with complements? A nice example could be:    That should look like: (image from )    I do not insist on the red color :)  I would like to use the simplest possible solution, as I would like to mass generate the exercises with the help of . So any suggestion dealing with gnuplot, R or any other opensource packages is welcome. Thank you!    UPDATE (25/01/2011): added details based on answers.  Thank you @Leo Liu, you helped me a lot! I modified a bit the code you suggested to be able to color the area outside of the two circles also (in the H universe), but have no idea how to set a background to that polygon also. The code:  \begin{tikzpicture}[fill=gray] % left hand \scope \clip (-2,-2) rectangle (2,2)       (1,0) circle (1); \fill (0,0) circle (1); \endscope % right hand \scope \clip (-2,-2) rectangle (2,2)       (0,0) circle (1); \fill (1,0) circle (1); \endscope % outline \draw (0,0) circle (1) (0,1)  node [text=black,above] {$A$}       (1,0) circle (1) (1,1)  node [text=black,above] {$B$}       (-2,-2) rectangle (3,2) node [text=black,above] {$H$}; \end{tikzpicture}   And the image generated:    I will also look for even odd rule in the near future which does not make sense for me at the moment but looks really simple and promising! How can I concatenate regex literals in JavaScript? Is it possible to do something like this?  var pattern = /some regex segment/ + /* comment here */     /another segment/;   Or do I have to use new RegExp() syntax and concatenate a string? I'd prefer to use the literal as the code is both more self-evident and concise. How do I determine the size of an object in Python? I want to know how to get size of objects like a string, integer, etc. in Python.  Related question:   I am using an XML file which contains size fields that specify the size of value. I must parse this XML and do my coding. When I want to change the value of a particular field, I will check the size field of that value. Here I want to compare whether the new value that I'm gong to enter is of the same size as in XML. I need to check the size of new value. In case of a string I can say its the length. But in case of int, float, etc. I am confused. I asked  that turned out to have multiple correct answers. How do I pick between them to determine which to accept?  All of the answers were different. They were not the same answer given multiple times. svmono template and `\mathcal` Why, with Springer's  svmono template, do the letters written with the \mathcal font change? It seems that \mathcal becomes \mathscr.  Edit: Look at this image:    With the svmono template \mathcal returns the first alphabet and not the (classical) latter.  Here the packages I use in my document:  \documentclass[envcountsame,envcountchap]{svmono}  \usepackage{subfiles} \usepackage[utf8]{inputenc}  \usepackage{mathptmx} \usepackage[bottom]{footmisc} \usepackage{microtype} \usepackage{stmaryrd}    \usepackage{amsmath} \usepackage{courier} \usepackage{mathrsfs}  \usepackage{amssymb}  \usepackage[all,cmtip]{xy} \usepackage{faktor} \usepackage{graphicx} \usepackage{mathdots} \usepackage[colorlinks={true},linkcolor={blue},citecolor={blue}]{hyperref} \usepackage[frame,width=15truecm,height=23.5truecm,center]{crop}   With this settings I have the above strange behavior of \mathcal. How can I '\input' a file without getting the implicit newline? A proof using Yoneda lemma Identify this story about a quickly healing woman Years ago I read a short story about a woman trying to commit suicide. However, because she had a extremely high rate of healing, her wounds were never fatal. The story ends with her being in the morgue after her heart was taken out for transplantation. Before a new heart could grow she was incinerated. The person who received her heart received the quick healing as well.  Does anyone know this story? I have a question about the following passage on pg. 89 of Zee's QFT in a nutshell:     At first sight, what Dirac wanted does not make sense. The equation is supposed to have the form "some linear combination of $\partial_\mu$ acting on some field $\psi$ is equal to some constant times the field." Denote the linear combination by $c^\mu\partial_\mu$. If the $c^\mu$'s are four ordinary numbers, then the four-vector $c^\mu$ defines some direction and the equation cannot be Lorentz invariant.   The simplest equation I can construct that he is referring to is  $$(c^{\mu}\partial_{\mu}-m)\phi(x)=0, $$  for $m&gt;0$. Taking $\phi(x)\rightarrow\phi(\Lambda^{-1}x)$, and $c^{\mu}\rightarrow\Lambda^{\mu}_{\ \ \nu}c^{\nu}$. Then, the left term transforms like   \begin{align*} \Lambda^{\mu}_{\ \ \nu}c^{\nu}(\Lambda^{-1})^{\sigma}_{\ \ \mu}\partial_{\sigma}\phi(\Lambda^{-1}x) &amp;= \delta^{\sigma}_{\ \ \nu}c^{\nu}\partial_{\sigma}\phi(\Lambda^{-1}x)\\ &amp;=c^{\sigma}\partial_{\sigma}\phi(\Lambda^{-1}x). \end{align*}  Then, we have that   $$ (c^{\sigma}\partial_{\sigma}-m)\phi(\Lambda^{-1}x)=0.$$  But doesn't this show that the equation is Lorentz-invariant? Abelian group (Commutative group) Prove that if in a group $(ab)^2= a^2 b^2$ then the group is commutative.  I am having a hard time doing this. Here is what I have so far: Proof:  $a^2 b^2= a^1 a^1 b^1 b^1$ =$aa^{-1}bb$ =ebb Hence,$aa^{-1}=e$  I am stuck, I do not know if this is the right process in proving this adding a point in a manipulate command Why is Dictionary preferred over Hashtable in C#? In most programming languages, dictionaries are preferred over hashtables. What are the reasons behind that? Windows Unable to Delete ._. File Dictionary application needs to download dictionary "Apple Dictionary" before use I'm repeatedly being asked to download the "Apple Dictionary" when I open the dictionary application.     Dictionary application needs to download dictionary "Apple Dictionary" before use.   This doesn't happen every time I open it. I haven't pinned down specific usage cases where this message appears, but I think it may be every time after I reboot my computer.  Is there anyway for the Dictionary application to remember that I have "Apple Dictionary" permanently? This has only started happening after I upgraded from OS X Mountain Lion to macOS Sierra. How to download a whole FTP site using command line? I need to download an FTP site (a web site source code actually) containing a very high quantity of relatively small files (downloading it with FileZilla took more than a day, but I believe it could be downloaded much faster if many files were downloaded at once). Unfortunately there is no SSH access to the site and no way to archive the files on the server side.  So at least the question is how to download a whole FTP site into a folder using command line tools. A better it'd be if the download could be parallelized by downloading many files simultaneously instead of one by one. Tag synonym suggestion textbox is overlapped by "Suggest" button How to find the sum of the sequence $\frac{1}{1+1^2+1^4} +\frac{2}{1+2^2+2^4} +\frac{3}{1+3^2+3^4}+.....$ Problem :   How to find the sum of the sequence $\frac{1}{1+1^2+1^4} +\frac{2}{1+2^2+2^4} +\frac{3}{1+3^2+3^4}+.....$  I am unable to find out how to proceed in this problem.. this is a problem of arithmetic progression... Please suggest how to proceed...Thanks.. Resetting Ubuntu to factory settings