I would like to create two bibliographies with two different names. My two bibliographies are books.bib and articles.bib  Doing :  \renewcommand{\refname}{References from Books}   after \begin{document} and then introducing the bibliograpy with :  \nocite* \bibliographystyle{plain}  \bibliography{books} %   works for books.bib.  I would like to the do the same thing with articles.bib and the title "References from articles".  Moreover, I need items to be referenced in alphabetical order in both cases.
I'm using biblatex and I have it set up like this:  In my bib file I have 3 sorts of entrys, online, booklet, and book.   And in my thesis I want them printed separate like this:  \printbibliography[heading=subbibliography,title={Books},type=book, nottype=url, nottype=booklet, nottype=online] \printbibliography[heading=subbibliography,title={Websites},type=online, nottype=book, nottype=booklet, nottype=url] \printbibliography[heading=subbibliography,title={Misc},type=booklet]   For some reason this won't work, it still puts the websites where the books should be. And vice versa. The booklet thing does work though, it only shows my booklet entries there.  I recently started using biblatex so this might be a stupid question.
Prison problem: locking or unlocking every $n$th door for $ n=1,2,3,...$ How to keep any Window "Always on Top"? Some software have an option for their window to be "Always on Top". Is there any way to get the same functionality for any window. Let me give an example where this would be useful.  Suppose I have a small browser window with real time stats from a game. The window is automatically updated at the rate of once every 10 seconds. I would like the small window to be always on top. so that I can just look at it whenever I want to, without actually going to it and at the same time I could continue working in my main application, which is at full screen.  Is there any Windows hack or App which can give me this functionality? Excuse my lack of knowledge and expertise in math,but to me it would came naturally that the cubic root of $-8$ would be $-2$ since $(-2)^3 = -8$.  But when I checked Wolfram Alpha for , real it tells me it doesn't exist.  I came to trust Wolfram Alpha so I thought I'd ask you guys, to explain the sense of that to me. What does Pirsig mean by "Quality"? What is actually the characteristic length in fluid dynamics description? In many fluid-dynamics models and quantities (, ... generally various  descriptions) there is a parameter (usually $L$ or $\ell$) descripted as characteristic linear dimension or characteristic length. What is that in intuitive and physical meaning? I understand the typical examples ( etc.) but I can't see so far any systematic generalisation.  What is the definition? (Or, maybe: What is its role during the derivation?) Transfer from JFK Terminal 2 to Terminal 4 I have family who does not speak English.  They are changing planes in JFK Airport and will most likely be transferring from Terminal 2 (Delta) to Terminal 4 (China Southern Airlines).  At first I thought that directing them to use the Airtrain would be best.  However, in doing more reading my understanding is that the Airtrain would mean they would need to go through security again.  I found this on Delta's site:   If they use the JITNEY Shuttle to change from Terminal 2 to Terminal 4, does that mean they would not need to re-clear Security?  Edit: They are flying TO China. They are going from Tampa -> NY JFK -> China. I meet with term 'empty function' from time to time. It's high time to understand its nature. What is field( set of arguments) and what is image? ( set of value)? Why are properties lost in the Cayley–Dickson construction? Motivating question:    I'm aware that one can construct a hierarchy of number systems via the Cayley–Dickson process:  $$\mathbb{R} \subset \mathbb{C} \subset \mathbb{H} \subset \mathbb{O} \subset \mathbb{S} \subset \ldots $$  "Reals" $\subset$ "Complex" $\subset$ "Quaternions" $\subset$ "Octonions" $\subset$ "Sedenions" $\subset$ $\ldots$  and that at each step you're given a multiplication table that tell how the elements interact. As you move up the ladder, certain "nice" properties are lost: ordering,  commutativity, associativity, multiplicative normedness, etc... Given the multiplication table, you can show that these properties don't hold.   Eric Naslund noted that "the first 4 are very special as they are the unique 4 normed division algebras over ℝ", no surprise then that these $2^n$-ions have found quite a bit of use. I'm interested in the sequence itself however, irrespective of how useful a $2^{256}$-ion might be (ducenti-quinquaginta-sex-ion?).   I feel like something deeper is going on here though that I don't understand. Why are these particular properties lost at each step? Is it possible to quantify the process such that, at the $2^n$-ion you can say something about the symmetry of the multiplication table*?  * I'm making an ansatz that there is a connection between the symmetry of the multiplication table and these "nice" properties. Unwanted faint lines connecting dashed double line Building on the answer  by wrtlprnft, I have the following code     \documentclass[tikz,margin=1cm]{standalone}    \usetikzlibrary{decorations.markings}    \begin{document}    \begin{tikzpicture}         \tikzstyle{arrowed double line}=[             dashed, double distance between line centers=3pt,             postaction=decorate,             decoration={                 markings,                 mark=between positions 10pt and -10pt step 20pt with {                     \arrow[thin,yshift= 1.5pt,xshift=.8pt]{&gt;}                     \arrow[thin,yshift=-1.5pt,xshift=.8pt]{&lt;}                 },             },         ]         \draw[arrowed double line] (0,0) --  (1,2);     \end{tikzpicture} \end{document}   which produces this:    I am unhappy with the faint transverse lines between the dashes. I don't even know why tikz decides to draw them.  Is there a way to get rid of them?  Thanks in advance to all replies.  PS the same thing occurs at the caps of double solid lines Can I just fit a cassette with more gears with the same derailleur? I've got a Boardman Road Sport which I use for commuting and doing reasonable length rides during the week etc. I have Shimano Claris as my rear derailleur and so is some of my groupset. I would like to upgrade my cassette to an either 9 or 10 speed to give me a greater variety of gears. To do this do I need to change my rear derailleur from 8 speed to Shimano 105 or something similar? Or can I just change my cassette? Do I also need to change my shifters as well? how to shuffle characters of strings in bash? i have this script where it generates random password but it needs to be shuffled. I couldnt find a way to do it. Please Help me.  num=("0" "1" "2" "3" "4" "5" "7" "8" "9") special=("@" "#" "$" "%" "*" "-" "+") upper=(A B C D E F G H I J K L M N O P Q R S T U V W X Y Z) lower=(a b c d e f g h i j k l m n o p q r s t u v w x y z) lower2=${#lower[*]}   #${lower[$((RANDOM%lower2))]} upper2=${#upper[*]}   #${upper[$((RANDOM%upper2))]} num2=${#num[*]}     #${num[$((RANDOM%num2))]} special2=${#special[*]} #${special[$((RANDOM%special2))]} echo "${special[$((RANDOM%special2))]}${num[$((RANDOM%num2))]}${lower[$((RANDOM%lower2))]}${upper[$((RANDOM%upper2))]}${lower[$((RANDOM%lower2))]}${upper[$((RANDOM%upper2))]}${lower[$((RANDOM%lower2))]}${upper[$((RANDOM%upper2))]}"   this is the output: @7nOyIaJ  how do I randomize this? heat weighting: failed to find solution for one or more bones I want to clear a element from a vector using the erase method. But the problem here is that the element is not guaranteed to occur only once in the vector. It may be present multiple times and I need to clear all of them. My code is something like this:  void erase(std::vector&lt;int&gt;&amp; myNumbers_in, int number_in) {     std::vector&lt;int&gt;::iterator iter = myNumbers_in.begin();     std::vector&lt;int&gt;::iterator endIter = myNumbers_in.end();     for(; iter != endIter; ++iter)     {         if(*iter == number_in)         {             myNumbers_in.erase(iter);         }     } }  int main(int argc, char* argv[]) {     std::vector&lt;int&gt; myNmbers;     for(int i = 0; i &lt; 2; ++i)     {         myNmbers.push_back(i);         myNmbers.push_back(i);     }      erase(myNmbers, 1);      return 0; }   This code obviously crashes because I am changing the end of the vector while iterating through it. What is the best way to achieve this? I.e. is there any way to do this without iterating through the vector multiple times or creating one more copy of the vector? How can I cast artificially darker shadows? I want to make certain shadows more prominent (using Cycles) without further illuminating the rest of the scene.  Example: I have a simple studio with a bowl of fruit and 3-point lighting.  The light looks great so I don't want to change it but I want the bowl to cast a darker shadow on the ground (without dimming the back-light).  Alternatively, and this would be really cool, an anti-light source.  Like a spot light that throws darkness instead of light. (Am I crazy for wanting this?)  Thanks! Residuals correlated positively with response variable strongly in linear regression How to retrieve GET parameters from JavaScript Can you make a non-polar electrolytic capacitor out of two regular electrolytic capacitors? There was some discussion on this question        which I don't see as being conclusively resolved:   "turns out that what might LOOK like two ordinary electrolytics are not, in fact, two ordinary electrolytics." "No, do not do this. It will act as a capacitor also, but once you pass a few volts it will blow out the insulator." 'Kind of like "you can't make a BJT from two diodes"' "it is a process that a tinkerer cannot do"   So is a non-polar (NP) electrolytic cap electrically identical to two electrolytic caps in reverse series, or not?  Does it not survive the same voltages?  What happens to the reverse-biased cap when a large voltage is placed across the combination?  Are there practical limitations other than physical size?  Does it matter which polarity is on the outside?  I don't see what the difference is, but a lot of people seem to think there is one.  Summary:   As posted in one of the comments, there's a sort of electrochemical diode going on:     The film is permeable to free electrons but substantially impermeable to ions, provided the temperature of the cell is not high. When the metal underlying the film is at a negative potential, free electrons are available in this electrode and the current flows through the film of the cell. With the polarity reversed, the electrolyte is subjected to the negative potential, but as there are only ions and no free electrons in the electrolyte the current is blocked. —    Normally a capacitor cannot be reverse-biased for long, or large currents will flow and "destroy the center layer of dielectric material via electrochemical reduction":     An electrolytic can withstand a reverse bias for a short period, but will conduct significant current and not act as a very good capacitor. —    However, when you have two back-to-back, the forward-biased capacitor prevents a prolonged DC current from flowing.  :     For circuit positions when reverse voltage excursions are unavoidable,   two similar capacitors in series connected “back to back” ... will create a   non-polar capacitor function ... This works because almost all the circuit voltage   is dropped across the forward biased capacitor, so that the reverse   biased device sees only a negligible voltage.   :     The oxide dielectric construction that is used in tantalum capacitors   has a basic rectified property which blocks current flow in one   direction and at the same time offers a low resistance path in the   opposite direction. Ubuntu 13.10 to 14.04 Lts does not upgrade, keeps showing error The update from Ubuntu 13.10 to 14.04 LTS does not work it keeps showing me an error as could not calculate the upgrade, even when I want it to get updated from the terminal it says the same error. I did not use the beta its the final Ubuntu 14.04 LTS.I have restarted my laptop for like 5-10 times no change. Disabling the software sources also does not help. What are the system requirements for each flavour of Ubuntu Desktop? 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 &quot;official  requirements&quot;, 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. Determine a user's timezone Is there a standard way for a web server to be able to determine a user's timezone within a web page?   Perhaps from an HTTP header or part of the user-agent string?