Was the Elder Wand really that great?
Would it be possible to create a wand more powerful than the Elder Wand?
Software Tester Skill Matrix with Levels I would like to know if there's a standard Skill set for Skill Matrix for a Software Tester of different levels, like for example, what are the skills needed for an Entry level tester as well as what technologies and responsibilities he needs. And for the Mid Level tester and Senior Level as well.  Note that I am working in a company who designs and develops websites. TikZ: remove margin, padding, border around nodes containing images I want to create a simple figure where images are connected with arrows. Here is what I did:  \begin{tikzpicture} \node[](A) {\includegraphics[width=0.2\textwidth]{a}}; \node[right=1mm of A](B) {\includegraphics[width=0.2\textwidth]{b}}; \draw[-&gt;] (A) to (B); \end{tikzpicture}     But I want the arrow to start and end right at the images with no space between. How can I do that? Why can't certain programs (like readlink) take input from a pipe? Tabular with p type columns to fill page width How to change horizontal alignment of \frac? Typing \frac{W+W^*}{2} gives a fraction in which the denominator appears to the eye to be in the wrong position. Is there a way to correct this, i.e. place the 2 in under the + (without using arbitrary negative spacing)? Use "does" in front of another verb in a question? What time does sound good to you?     What time sounds good to you?    Is there a difference? How come such different methods result in the same number, $e$? I guess the proof of the identity $$ \sum_{n = 0}^{\infty} \frac{1}{n!} \equiv \lim_{x \to \infty} \left(1 + \frac{1}{x}\right)^x $$ explains the connection between such different calculations. How is it done? Note: Suppose $f(z)$ is a polynomial or a proper/strictly proper rational function.   Can someone demonstrate why if all coefficient of $f(z)$ are real then relation $f(\bar z)$ = $\bar {f(z)}$ hold  Is there a theorem for this result? Unable to set DYLD_FALLBACK_LIBRARY_PATH in shell on OSX 10.11.1 Is there a website that summarizes the luggage and check-in requirements for each airplane company? I don't travel much by plane but I use a wide variety of companies. Since there is not much harmonization, specially with LCC, each one has its own requirements about luggage size, weight, extra luggage price, need for on-line check-in and printed ticket.  Each time I fly I ask my self what are the requirements, and although I can check them online at the official website this can't be quick, sometimes I leave it for last or, with so many, I just confuse airline requirements.  Is there a website or resource that lists this information? This would be very useful to quickly check or just compare requirements. $A^A$ in category of graphs (reference is Lawvere/Schanuel, Session 31, Ex. 1)  I'm trying to calculate the exponential object $A^A$ and its evalution map $e \colon A \times A^A \to A$ in the category of graphs, where $A$ is the "arrow graph" (ie. one arrow and two dots).  In the following, $D$ is the graph with one dot and no arrows, $1$ is the terminal object in this category (graph with one dot and one arrow, the loop).  So far I have:   The points of $\mathbf{1}\to A^A$ correspond to the maps $A\to A$ (via two standard isomorphisms), and since $\mathbf{1}$ is the loop, and there is one map of graphs $A \to A$, there is one loop in $A^A$. The dots $D\to A^A$ correspond to the maps $A \times D \to A$, of which there are four, hence four dots in $A^A$. The arrows $A \to A^A$ correspond to the maps $A \times A \to A$, of which there are four, hence four arrows in $A^A$.   But I'm stuck on how to put these together to constitute $A^A$ and its evaluation map. When is an elected moderator shown as "departed" on the election page? On Philosophy, one of the elected moderators has since deleted their account, and they're shown as "Departed" on :        However, , one of the elected moderators still has their "previous" flair shown in place, despite the fact that they've already resigned and left the Network completely in the wake of the recent events.        , the same happens (old flair remains), but without the clickable &lt;a&gt; around the image, and with a noticeable :        This looks inconsistent, so when exactly will a placeholder image showing "Departed" replace the flair for a departed election winner? C++ performance of accessing member variables versus local variables Is it more efficient for a class to access member variables or local variables? For example, suppose you have a (callback) method whose sole responsibility is to receive data, perform calculations on it, then pass it off to other classes. Performance-wise, would it make more sense to have a list of member variables that the method populates as it receives data? Or just declare local variables each time the callback method is called?  Assume this method would be called hundreds of times a second...  In case I'm not being clear, here's some quick examples:  // use local variables class thisClass {     public:         void callback( msg&amp; msg )         {             int varA;             double varB;             std::string varC;             varA = msg.getInt();             varB = msg.getDouble();             varC = msg.getString();              // do a bunch of calculations          }  };  // use member variables class thisClass {     public:         void callback( msg&amp; msg )         {              m_varA = msg.getInt();              m_varB = msg.getDouble();              m_varC = msg.getString();               // do a bunch of calculations         }      private:         int m_varA;         double m_varB;         std::string m_varC;  }; I've always wondered why the number of protons in the Universe exactly matches the number of electrons. They are such different particles with totally different cross sections. So, first of all, is this true? And, secondly, how could it be that they have been produced in the same amount after the Big-Bang? Recently, my iPhone 5 was stolen, and while I have a new iPhone 6, I received a message from a number of someone claiming to be in possession of the device, with a new number.   All images, contacts, Outlook mail, you name it, are still on the device.  While I realize it's my fault for not having it connected to iCloud to wipe manually, is there anything I can do to have this sensitive information wiped from the device? Is there any way to specify a suggested filename when using data: URI? If for example you follow the link:  data:application/octet-stream;base64,SGVsbG8=  The browser will prompt you to download a file consisting of the data held as base64 in the hyperlink itself.  Is there any way of suggesting a default name in the markup?  If not, is there a JavaScript solution? As you are all most likely aware already all domain registrars ask for your personal information.   Such personal information includes:   Forename and surname Address information Email address Telephone number   Personal information via WHOIS  Depending on the domain type such as  or  this information may become immediately available after the registration of the domain via a simple whois. If you do not want that (and in most cases you certainly don't) they offer a service where you can remove this information from the whois service but of course hiding your personal information adds yearly costs to the domain  purchase.  What happens if I use fake details when registering a domain? As of today, a  has been found affecting versions 1.0.1 through 1.0.1f (inclusive) and 1.0.2-beta.  Since Ubuntu 12.04, we are all vulnerable to this bug. In order to patch this vulnerability, affected users should update to OpenSSL 1.0.1g.  How can every affected user apply this update now? A common good practice in Machine Learning is to do feature normalization or data standardization of the predictor variables, that's it, center the data substracting the mean and normalize it dividing by the variance (or standard deviation too). For self containment and to my understanding we do this to achieve two main things:   Avoid extra small model weights for the purpose of numerical stability. Ensure quick convergence of optimization algorithms like e.g. Conjugate Gradient so that the large magnitude of one predictor dimension w.r.t. the others doesn't lead to slow convergence.   We usually split the data into training, validation and testing sets. In the literature we usually see that to do feature normalization they take the mean and variance (or standard deviation) over the whole set of predictor variables. The big flaw I see here is that if you do that, you are in fact introducing future information into the training predictor variables namely the future information contained in the mean and variance.  Therefore, I do feature normalization over the training data and save the mean and variance. Then I apply feature normalization to the predictor variables of the validation and test data sets using the training mean and variances. Are there any fundamental flaws with this? can anyone recommend a better alternative? I want to boot Ubuntu into recovery mode but there is no grub menu entry allowing me to do so. I pressed e and now I am able to edit boot options. It looks like that:  setparams 'Ubuntu , with Linux 3.6.0-26-generic'  recordfail gfxmode $linux_gfx_mode insmod gzio insmod part_msdos insmod ext2 set root='(hd0,msdos5)' search --no-floppy --fs-uuid --set=root &lt;uuid&gt; linux /boot/vmlinuz-3.5.0-26-generic root=&lt;uuid&gt; ro ipv6.disable=1 quirt splash $vt_handoff initrd /boot/initrd.img-3.5.0-26-generic   The  documentation says:     Boot to the recovery mode even if it is not listed on the menu:         Remove existing kernel options from the linux line and add single      But this sentence doesn't make any sense, maybe the wiki page is broken somehow. How to modify the boot menu to boot directly into recovery mode?  Note: I don't have access to grub config or anything else, only the boot menu edit page is available.