Input Menu Screen Method always Returns 0

I was assigned to create a menu driven program which contained a function that showed the menu screen/get the user input, but displaymenu() always and only returns 0 instead of the new inputted number.  I'm pretty new to programming and I've googled everything I can think of and I'm pretty stuck.  import java.util.Scanner;  public class menuDriven {    public static void main(String[] args)    {       int menuSelection=0;       double inches, centimeters, feet, meters, miles, kilometers;        Scanner keyboard = new Scanner(System.in);        displayMenu(keyboard, menuSelection);         switch(menuSelection)       {       case 1:          inchesToCentimeters(keyboard);          break;        case 2:          feetToMeters(keyboard);          break;        case 3:          milesToKilometers(keyboard);          break;       }     } // end main     public static int displayMenu(Scanner keyboard,  int menuSelection)     {     System.out.println("1. Convert inches to centimeters");    System.out.println("2. Convert feet to meters");    System.out.println("3. Convert miles to kilometers");    System.out.println();     System.out.println("Enter your selection");    menuSelection = keyboard.nextInt();     while (menuSelection < 1 || menuSelection > 3)       {          System.out.println("Please enter 1, 2, or 3.");          menuSelection = keyboard.nextInt();       }    return menuSelection;    }     public static void inchesToCentimeters(Scanner keyboard)    {       double inches, centimeters;       System.out.print("Enter the number of inches: ");       inches = keyboard.nextDouble();       centimeters = inches * 2.54;       System.out.println("That is equal to " + centimeters + "  centimeters.");     }     public static void feetToMeters(Scanner keyboard)    {       double feet, meters;       System.out.println("Enter the number of feet: ");       feet = keyboard.nextDouble();       meters = feet * 0.3048;       System.out.println("That is equal to " + meters + " meters.");    }     public static void milesToKilometers(Scanner keyboard)    {       double miles, kilometers;       System.out.println("Enter the number of miles: ");       miles = keyboard.nextDouble();       kilometers = miles * 1.609;       System.out.println("That is equal to " + kilometers + "  kilometers.");    } } // end class   The program should take the user input 1, 2, or 3 and then take that number to the switch and display the code.


If you live in a two-dimensional world, would it be possible to explain the angular momentum?


Square root sign has dotted line (PGF/TikZ + XeLaTeX). Is this a bug? Is there a workaround?

I am encountering a number of problems using XeLaTeX and PGF/TikZ.  One concerns the  spy library and seems well-documented.  Today I have encountered another.  Here is a minimal working example.  \documentclass{standalone} \usepackage{tikz} \begin{document} \begin{tikzpicture}[auto]    \draw[thin, dotted] (0,0) -- node {$\sqrt{r_1 r_2}$} (3,0); \end{tikzpicture} \end{document}   Compiling with XeLaTeX one sees that the line which extends the surd in the square root is also dotted (!):    This does not happen with PDFLaTeX, for example:    Is there a workaround?


Appended anchor tag click event does not adding active class to it. (appended tag is generated by click event of another anchor tag)

Thanks in advance for help.  You can better understand problem by observing following code:  Save

link 1

  $('.save-btn').click(function() {     $('ul').append('
link 2
')     return false; })  $('.newLink').click(function() {     $(this).addClass('active') // ".newLink" is not adding "active class"    return false; });   I want to simply add active class to link having class name "myLink" by click event.  I know the problem is "click event", appended anchor tag on window.load is adding active class perfectly.    Image Description: Link "Abc Xyz" should add "active class" on click (active link will have blue background according to my image)


Custom URL Expiration Settings in Marketing Cloud

I have a requirement to set URL expiration to 24 hours, but the system only lets me choose a timeframe between 60-730 days:     Administrators can set links to expire in email sends at any point between 60 and 730 days or 2 years.     I am trying to figure out an alternative way to make this work - any ideas or experience in this area?  Please note that this is not a one-off send, where I could simply re-publish the landing page after 24 hours, this solution will be a part of an automated process.  Thanks!


I have tried to replace a string in an array then conver it to string but it was not like I want. Here is my example:      String data = "ABC   00 0 03 54            BTT";     String[] tokens = data.split("\\s+");     for(int i=0; i<tokens.length; i++){         if(tokens[i] == "BTT"){            tokens[i] = tokens[i].replace("BTT"," ");         }     }     data = Arrays.toString(tokens);     Log.log(Log.VRB, "DEBUG: field =" + data);   OUTPUT: DEBUG: field =[ABC, 00, 0, 03, 54, BTT]  But I had tried to get this output: DEBUG: field = ABC  00 0 03 54  Can anyone give me the idea how can I fix it?  Thanks.


Can you configure Windows to open JAR files like ZIP files without a 3rd party tool?

I'd like to be able to examine the contents of a JAR file without having to install Winzip or some other tool and without having to rename the file.  Windows Explorer can open ZIP files just fine; is there some registry setting I can use to let it treat JARs like ZIPs?


Beyond the sphere, are there other Riemannian manifolds that admit non-trivial conformal maps?

A conformal map of a Riemannian manifold $M$ with metric $g$ is a diffeomorphism $f: M\to M$ such that $f^\star g = \Omega g$ for some smooth, positive $\Omega: M \to \mathbb{R}$. If $\Omega(x) = 1\ \forall\ x \in M$, the map $f$ is called an isometry. For example, the sphere $S_n$ admits a Lie group of conformal maps, the , which in general are not isometries: isometries form a proper subgroup of the Mobius group. Two Riemannian manifolds $(M, g)$, $(N, h)$ are conformally diffeomorphic if there is a diffeomorphism $\phi: M\to N$ such that $f^\star h = \Omega g$ for some smooth, positive $\Omega: M \to \mathbb{R}$. Clearly, if $f$ is a conformal map on $N$, $\phi^{-1}f\phi$ is a conformal map on $M$. I would like to know if there are Riemannian manifolds, not conformally diffeomorphic to $S_n$, that admit conformal maps that are not isometries. For example, I think that the only conformal maps of hyperbolic space $H_n$ are isometries (although I'd be happy to see a counterexample).


I am right now writing my master thesis in computer science about a visualization topic. Since the core stuff of my thesis is a complex 3D visualization that only quite sends its message through user interaction (click/drag/turn to view from different angles), my only option to get this message across on paper would be a bunch of screenshots.  30 screenshots side by side or spread across a couple of pages should be ok, but I thought it'd be rather nice to have some kind of flipbook where the screenshots are in a specific spot spread on consecutive pages.  Is this a good idea at all?  For now this is what I am using:  \usepackage[automark]{scrpage2} \ofoot[\pagemark]{\pagemark}   since there are less screenshots than pages of my thesis I would start these on some specific page in the middle of the thesis (is that even a good idea, I'm starting to doubt this whole thing...) like this:  \cfoot[{ \IfFileExists{pics/s\thepage.png}{ \raisebox{-40mm}{\includegraphics[trim = 40mm 40mm 40mm 40mm,clip,height=40mm]{s\thepage.png}}}{\raisebox{-40mm} {}} }]{ \IfFileExists{pics/s\thepage.png}{     \raisebox{-40mm}{\includegraphics[trim = 40mm 40mm 40mm 40mm,clip,height=40mm]{s\thepage.png}}}{\raisebox{-40mm} {}}   So as you see I was putting the screenshots in the footer, which is also not ideal ( ideal would probably be an area on the lower right of the page where the screenshots would go and the text would wrap around, but I don't know how to do that).  So with this in place I can not really control the footer. the \pagemark jumps lower or highter when the pages start with the screenshots in the footer compared to those without screenshots, and also the sceenshots will end up very close to the text - I'd like to see a larger space there but I can't control the footer height.  What to do? I'm thankful for every input, also for people telling me: "don't do this!" ( or the contrary)  EDIT: just so you know what I'm talking about:    These are microstructures. The thick brownish/pink lines represent grains in copper. the greyish thing in the middle is the separating interface between the two grains. The thinner lines form a grid representing the crystal orientations. This output is quite customizable, I could change colors, switch of either grid, change the grid density and obviously change the view.  I was just now thinking of including for each grid one set of 3 thick Arrows that the eye could make out easier on paper. I'll probably do this. Also, I'll probably not go this way of doing the flipbook somewhere in the footer or margin, but actually put just a few of these shots consecutively as figures in the appendix.


Does this character in "Code Geass: Lelouch of the Rebellion" die?

Does      Lelouch Vi Britannia   survive at the end of Code Geass: Lelouch of the Rebellion?  Some people say that      he's seen in Code Geass: Akito the Exiled   but isn't this before the events of the first two seasons?


R1  = 2Ω R2 >= 22kΩ D2 = 1N4148, or 1N400x (x is a number) U1 =  (MIC4452YN is the through-hole version) Q1 =    So basically I want to run the circuit from a NE555 timer because I don't have the MIC4452 to drive the MOSFET. I will be using an  MOSFET. I have no clue how to wire everything up ... and other components I need. If someone could walk me through the connections for the circuit... ?


What is difference between `` and $() for command-substitution in bash scripting?

I'm new to Linux and StackExchange. My English is pretty bad, and I'm sorry for mistakes.  What is the differences between `` and $()? Does it matter what to use and when?  I'll be grateful for explanation.


How do I find which row is using the most space in my database?

I have a SQL Server 2012 database which users can attach files to (mainly Jpgs) however the table size is 130mb with only 20 records.   I need to find out which row is using the most amount of space.  The data is stored as varbinary  Thanks


What's the best way to pipe the output from an java.io.OutputStream to a String in Java?  Say I have the method:    writeToStream(Object o, OutputStream out)   Which writes certain data from the object to the given stream. However, I want to get this output into a String as easily as possible.  I'm considering writing a class like this (untested):  class StringOutputStream extends OutputStream {    StringBuilder mBuf;    public void write(int byte) throws IOException {     mBuf.append((char) byte);   }    public String getString() {     return mBuf.toString();   } }   But is there a better way? I only want to run a test!


How can infinite information be theoretically encoded or stored in a single qubit?

I've just gotten started with Nielsen and Chuang's text, and I'm a little stuck. They mention that theoretically, it would be possible to store an infinite amount of information in the state of a single qubit. I'm not sure I completely comprehend this.    Here's how I rationalized it: You take all the information you want to store, put it in binary form, and make it the real component of $\alpha $ or $\beta$ (the coefficients of the computational basis states).   Now I'm not sure if I've understood it right, but since it's still fuzzy in my head it would be great to get some kind of ELI5 explanation or possibly a more detailed picture of how this would, even theoretically, be possible.    Apologies if the question doesn't meet standards. I'm new to the forum and would be open to feedback regarding asking questions or answering them.


Short story where humans don't understand the concept of "impossible"

There's a story that I read at some point several years ago, but I can't remember when or where. My best guess is that it was either in an out of print book of older SF stories (probably 30+ years old) or it was an online post someplace (probably less than 10 years old).  The premise, as best as I can remember it, is that galactic civilizations have decided (at some point in the distant past) that humanity is too dangerous and have effectively quarantined our solar system. But a couple of aliens are wondering just what could possibly be so scary about us. So they decide to build a laboratory environment that would be absolutely impossible to escape from and abduct one single human being and stick him in it, in order to observe him.  There are multiple levels of security ensuring that there's no way to possibly escape. But it turns out that the thing that distinguishes humans from all other intelligent beings in the galaxy is that they just can't comprehend the concept of something being "impossible". So, despite the fact that there's no chance of success, the human insists on repeatedly trying time and again to get out.  Of course, he eventually succeeds. And steals the aliens' ship. And they realize that they've made a terrible, terrible mistake.  Does anyone else remember this story? One thing I do know is that it's not "With Friends Like These..." by Alan Dean Foster (I checked that one already).


Well i tried to make a loop within a loop, kinda like that movie Inception. But it messes up some how, the second loop won't stop when i enter "N" for no, and won't go back to the the 1st loop, which is "Continue with another set?", when i enter "Y" for yes. Instead it keeps going back to the "What value to check?" no matter what :(  while (true){     // 2. Ask the user for size of arbitrary numbers.     System.out.print("Please enter a size for arbitray numbers: ");     int size = indata.nextInt();      int [] SortedNumbers = new int [size];      // 3. Process arbitrary numbers and remove all duplicates     int numDuplicates = generate_data(SortedNumbers);      // 4. Print the numbers and number of duplicates     printArray(SortedNumbers, numDuplicates);      while (true){         // 5. Ask user for target value         System.out.print("\nWhat target value to check? ");         int target = indata.nextInt();          // 6. Perform linear and binary search         int linearVal = linear_search(SortedNumbers,target);         int binaryVal = binary_search(SortedNumbers,target);         if (linearVal == -1)             System.out.println("Linear search: " + target + " does not exist in the array.");         else              System.out.println("Linear search: " +target + " is in location " + linearVal);          if (binaryVal == -1)             System.out.println("Binary search: " + target + " does not exist in the array.");         else              System.out.println("Binary search: " +target + " is in location " + binaryVal);          // 7. Repeat steps 5 and 6 until the user is satisfied.         System.out.println("Continue? Y/N");         String answer = indata.next();         if (answer=="Y"){             break;         }     }     // 8. Repeat steps 2-7 until the user is done working with different arbitrary sets of numbers.     System.out.println("Continue with another set? Y/N");     String answer2 = indata.next();     if (answer2=="Y"){         break;     } }   So technically i need it to stop when i enter N, or ask me if i want "a new set" when i enter Y, and then on the second loop go back to "value to check" on N, or start from the beginning for Y.


How to maintain the calories in rice (which were present in it in its raw form) after cooking it?

I searched Google with the following keywords:     calories in 1 tbsp brown rice   The result was:        As you can see the calories, after cooking have severely reduced.   What can I do to maintain the default level of calories in cooked rice?  I am not talking about increasing calories by adding extra materials like oil. I wish to know some cooking method which does not destroy the calories so much.  Note: I do NOT throw any water during the process of cooking rice.


Why is it legitimate to solve the differential equation $\frac{dy}{dx}=\frac{y}{x}$ by taking $\int \frac{1}{y}\ dy=\int \frac{1}{x}\ dx$?

Answers to this question  assert that to find a solution to the differential equation $$\dfrac{dy}{dx} = \dfrac{y}{x}$$ we may rearrange and integrate $$\int \frac{1}{y}\ dy=\int \frac{1}{x}\ dx.$$  If we perform the integration we get $\log y=\log x+c$ or $$y=kx$$ for constants $c,k \in \mathbb{R}$.  I've seen others use methods like this before too, but I'm unsure why it works.  Question: Why is it legitimate to solve the differential equation in this way?


Clarification of why DNS zone files require NS records

This question was originally asked here:   To summarise: "When I go to my registrar and purchase example.com , I will tell my registrar that my nameservers are ns1.example.org and ns2.example.org".  But please can somebody clarify the following:  After registration, the .com registry will now have a record that tells a resolver needs to visit ns1.example.org or ns2.example.org in order to find out the IP address of example.com. The IP address resides in an A record in a zone file on ns1.example.org and has a identical copy on ns2.example.org.  However, inside this file, there must also be 2 NS records which list ns1.example.org and ns2.example.org as the nameservers. But since we are already on one of these servers, this appears do be duplicated information.   The answer originally given to the question said the nameservers listed in the zone file are "authoritative". If the nameservers didn't match, then the authoritative nameservers would take precedence. That's all very well and good, but the resolver arrived at the nameserver using the nameservers listed in the .com registry, and if the nameserver's didn't match, then the resolver would be looking for the zone file on the wrong nameserver and wouldn't be able to find it.  Or is it a case of the .com registry extracts nameserver information from the zone file ns record? (But then I suppose if you change the ns record the zone file without telling the registry, then it would have no way of knowing where to look.)   Thanks


If $(\limsup_{n\to\infty} x_{n})\cdot(\limsup_{n\to\infty} 1/x_{n})=1$, then the sequence $x_n$ converges

${x_{n}}$ is a sequence in $\mathbb{R}$ where $n\geq 1$ such that all $x_{n} >0$. If  $(\limsup_{n\to\infty} x_{n})\cdot(\limsup_{n\to\infty} 1/x_{n})=1$, how can I show that ${x_n}$ converges? I am thinking about using the contrapositive  of the statement but I'm not sure if that's the best way. Thank you.


For a formula $ \gamma = r \iff (p_1 \vee p_2) $ there is true that: $\rho \models \gamma \iff \rho(r) = \max(\rho(p_1), \rho(p_2))$  Is it a true for every formula r?


My Ubuntu only allowed guest login to desktop.Once I login to System as user ,It jump to login interface again and very quick  please i need a simple answer with a simple langauge


I want to achieve a table with the headers being rotated 90 degree so that it appears bottom up.   I use the following code with both rotation 90 and -90 but I am facing different errors. Here is the code:   \documentclass[graybox,envcountchap,sectrefs]{svmono} \usepackage{rotating} \usepackage{amssymb}% http://ctan.org/pkg/amssymb \usepackage{pifont}% http://ctan.org/pkg/pifont \usepackage{array} \newcolumntype{P}[1]{>{\centering\arraybackslash}p{#1}}  \begin{document} \begin{table} \begin{tabular}{ | P{4cm} | P{1cm} |  P{1cm} } \hline col 0 & \begin{rotate}{90} Col1 \end{rotate} & \begin{rotate}{-90} Col2 too much text is written here that i want to split on multiple line but rotated 90 degree \end{rotate}\\[25ex] \svhline first row & \checkmark & \ding{55} \\ \hline \end{tabular} \end{table} \end{document}   Here is the output:   So my questions are:   How to start from the button towards the top like first 'Col1' but to start from the bottom of the cell How to make it fit the cell size and use multi rotated line, shall I do that by hand or can it be made in an automatic manner, and if by hand how can that be done   Here is a link to the class


Bringing my Japanese akita dog with me from Europe to the US, preferably in cabin

I would like to bring my Japanese akita dog with me from Europe to the US. And I would really like it to be with me in the cabin. Which air companies allow that?


Combine Sky texture with other layers with alpha channel

I have a scene with two different render layers. The first one is a background with Sky texture. The second one is some images of mountains with alpha channel. For second layer I need Transparency to have an alpha channel to get a background with Sky texture as a sky. The thing is if I enable transparency, the first layer renders as one total alpha channel. If I disable transparency the second layer renders without alpha channel and I can't apply the first layer as sky because the second layer overlaps it by solid black. if I render them separately I lose one of them.


Why is it right to say you die "from" an illness instead "of" an illness?

I just found this sentence in an article in :     Lovelace died in great pain at 36, from uterine cancer.   And I'm confused about the use of "from". I know "from" is used to express physical origin (e.g., He moved from Paris), but in this case the preposition is used to state the cause of something (the death of somebody). Is this use valid?


Dynamic Approach to factorial of a number in java, giving NULLPOINTEREXCEPTIN

I developed this code to calculate the factorial in java by the dynamic approach. But it's throwing  an exception NULLPOINTER, here is my code:    public class test {                    int fact[];int i;                    int fact(int n) {                 for ( i =2;i<n;i++) {                  fact[0]=1;           fact[1]=1;           fact[i]=fact[i]*fact[1]*fact[0];            }return fact[n];     }     public static void main(String args[]) {         int N=5;          test t=new test();         int arr[]=new int[N];          for(int j=0;j<N;j++) {             arr[j]= t.fact(j);         }         for(int j=0;j<N;j++) {             System.out.println(arr[j]);         }         }     }  </code></pre>   I am a beginner in java, please can you correct my mistake. Thanks in advance.


Does storage capacity affect hard drive performance?

I read somewhere that smaller (in terms of disk space) hard drives are faster than equivalent but bigger hard drives. How true is this? In other words, say I have two hard drives. Both are of the exact same brand and specs, but one is an 80GB while the other is 500GB. Which would be faster? Or does storage capacity not have any effect on speed at all?


I need query of looping in stored procedure for table like this:  Table Matrix Report  | Nama  | Motor   | |-------|---------| | Abdul | Vario   | | Abdul | Beat    | | Mei   | Supra   | | Leli  | Supra   | | Budi  | Megapro | | Ali   | CB150   |   Output :  | Nama   | Vario | Beat | Supra | Megapro | CB150 | |--------|-------|------|-------|---------|-------| | Abdul  | 1     | 1    | 0     | 0       | 0     | | Mei    | 0     | 0    | 1     | 0       | 0     | | Leli   | 0     | 0    | 1     | 0       | 0     | | Budi   | 0     | 0    | 0     | 1       | 0     | | Ali    | 0     | 0    | 0     | 0       | 1     |   I need dynamic query because if I added new data, they automatically sum up.


How can I trick Minecraft into thinking two computers are on the same wifi network?

Minecraft's got an "Open to LAN" feature, which can be used to set up a local server when two computers running Minecraft are on the same network. Some young relatives of mine use this to play together whenever they're in the same house, but they'd like to be able to play together from their respective residences.  A server is not optimal because it's a bit complex. I've tried using Tunngle to spoof that the computers are on the same connection to no avail.  How can I convince Minecraft's "Open to LAN" that their two separate computers are on the same network?


Help creating 3D solids of revolution in pgfplots?

I have done a lot of plotting in 2D using pgfplots but I am new to the 3D portion. I am attempting to illustrate a solid of revolution. For example, I have the area under the curve y = x^2 + 1 on the domain [0,5] (along with the curve rotated about both the x- and y- axes) illustrated with the following:   \documentclass[24pt, letter]{report} \usepackage[fleqn]{mathtools} \usepackage{amsthm, amssymb} \usepackage{tikz} \usepackage{pgfplots} \pgfplotsset{compat=1.9} \pagenumbering{gobble}  \begin{document}   % Curve + Area Underneath   \begin{tikzpicture}     \begin{axis}[title={$y=x^2+1$},                  xticklabels={,$a$, , , , ,$b$} ,                  yticklabels=\empty,                  x=1.0cm,                  y=0.2cm,                  xmin=0, xmax=5.4,                  ymin=0, ymax=26.9,                  axis x line=bottom,                  axis y line=left                  ]       \addplot[smooth,thick,domain=0:5, fill=blue!50]{1+x^2}\closedcycle;       \node at (axis cs:3.75,4) [anchor=south]{$A$};     \end{axis}    \end{tikzpicture}    % Curve Rotated about y-axis   \begin{tikzpicture}     \begin{axis}[view={45}{45}]       \addplot3[surf,shader=interp,samples=50,                 domain=0:5,y domain=0:2*pi,z buffer=sort]         ({x*cos(deg(y))}, {x*sin(deg(y))}, {x^2+1});     \end{axis}   \end{tikzpicture}    % Curve Rotated about x-axis   \begin{tikzpicture}     \begin{axis}[view={45}{45}]       \addplot3[surf,shader=interp,samples=50,                 domain=0:5,y domain=0:2*pi,z buffer=sort]         (x, {(x^2+1)*cos(deg(y))}, {(x^2+1)*sin(deg(y))});     \end{axis}   \end{tikzpicture} \end{document}    Is it possible to further the illustration by not only drawing the curve, but also the area under it? For example, when rotating about the y-axis, I'd like it to look not like a bowl, but like a cube with a bowl hollowed out of the top. Eventually I'd even like to be able to illustrate this with the area bounded by two curves, such as the area bounded by y=x^2+1, x=4, y=0, y=37.  Additionally, how would I draw the rotation about an arbitrary axis, such as the line y = -1 or x = 6?


What happens if you Twin Spell a spell that requires concentration?

Can your character maintain concentration on two spells?  If concentration is broken, do both spells fall, or are separate checks made on each?


Quantum mechanics - how can the energy be complex?

In section 134 of Vol. 3 (Quantum Mechanics), Landau and Lifshitz make the energy complex in order to describe a particle that can decay:  $$ E = E_0 - \frac{1}{2}i \Gamma. $$  The propagator $U(t) = \exp(-i H t)$ then makes the wavefunction die exponentially with time.  But also, $H$ is non-Hermitian.  My question: Do we have to modify the basic postulates of quantum mechanics (as described by Shankar, say, or the earlier sections of Landau & Lifshitz) to describe unstable particles?


Do edit suggestions make community wiki superfluous?

The FAQ says that Community Wiki works:     by transferring ownership of the post   from the original author to the   community. They make the post easier   to edit and maintain by a wider group   of users, but they do not contribute   to any user's reputation.   But using the new edit suggestion system, everyone can edit. It's no longer true that community wiki makes a post easier to edit.  Does community wiki still serve a function?    What are good examples of community wiki mode doing what it's supposed to do?


Multiple SSL domains on the same IP address and same port?

This is a  about Hosting multiple SSL websites on the same IP.   I was under the impression that each SSL Certificate required it's own unique IP Address/Port combination. But the  is at odds with this claim.  Using information from that Question, I was able to get multiple SSL certificates to work on the same IP address and on port 443. I am very confused as to why this works given the assumption above and reinforced by others that each SSL domain website on the same server requires its own IP/Port.  I am suspicious that I did something wrong.  Can multiple SSL Certificates be used this way?


Open set as a finite union of closed sets

I was studying a text () when in a proof the author stated:  !  If I got it right, the author says that $\widetilde{U}$ (a nonempty open connected set in $\mathbb{C}^n$) is a finite union of closed sets, so one of these closed sets must have nonempty interior.   I tried to prove it but I could not. I think it is a very simple topological detail I am missing.


Applying to top CS PhD programs with a great record but bad GRE scores

I have a good GPA (over 3.5) from a top 5 CS school. I also have lots of research experience and a few publications. I also expect to have very good recommendations. The only problem is that I did badly on the GRE general exam (just under below average). The exam seems like a big scam, so studying for it felt like a waste of time.  One of JeffE's  mentions that schools filter applicants into three piles based on GPA and GRE: MAYBE, PROBABLY NOT, and NO. Will my GRE scores land me in the PROBABLY NOT pile, even though I have an otherwise excellent record?  Will my GRE hurt my chances of getting into CMU and Stanford? Should I try to retake them, even though it's getting late? Application deadlines are around December 13.  Edit: should I say something about my bad GRE scores in the statement of purpose, or do something else if I don't end up retaking them?


Use of expired French ID to travel to the UK for 2 weeks

A friend of mine is planning to come to London in April but she knows that her French ID expires while she is here. As far as the French authorities is concerned an expired ID card is still valid for the next 5 years. Will she have problem at Immigration at Gatwick airport when she goes back to France?


Finding the default application for opening a particular file type on Windows

I'm developing an application targeting .NET Framework 2.0 using C# for which I need to be able to find the default application that is used for opening a particular file type.  I know that, for example, if you just want to open a file using that application you can use something like:  System.Diagnostics.Process.Start( "C:\...\...\myfile.html" );   to open an HTML document in the default browser, or  System.Diagnostics.Process.Start( "C:\...\...\myfile.txt" );   to open a text file in the default text editor.  However, what I want to be able to do is to open files that don't necessarily have a .txt extension (for example), in the default text editor, so I need to be able to find out the default application for opening .txt files, which will allow me to invoke it directly.  I'm guessing there's some Win32 API that I'll need to P/Invoke in order to do this, however a quick look with both Google and MSDN didn't reveal anything of much interest; I did find a very large number of completely irrelevant pages, but nothing like I'm looking for.


Difference between args and *args as inputs for a function

This question is to try to understand what the asterisk(*) works. As known, * could be used with args to make the function accept positional keywords later. Also, it could work as an operator to unpack a container. So my question is:  how to know its functionality?   def product(*num):     prod = 1     for i in num:         prod*= i     return prod  def product2(num):     prod = 1     for i in num:         prod*= i     return prod  num = [2,3,5]   So when you use different function, you will get different result. I just wanted to know what happened here? Thanks.


Utilizing if statements with "&&" in Java, statement not printing despite criteria being fulfilled

I'm trying to make a basic "20 questions" type of thing to learn how to use if statements with boolean comparators like && in them. However, my "if" statements are not, uh, "doing" (sorry) even though their criteria are being satisfied (as far as I can tell).   When I compile, no matter what "answers" I input, the only output I get is "I'd ask you if I'm right..." ALA:   Think of an object, and I'll try to  guess it! 1. Is it an animal, vegetable, or mineral?vegetable Is it bigger than a breadbox?yes I'd ask you if I'm right, but I don't really care   I tried googling and searching but I feel like I'm missing out on something so basic that I'm just not seeing it.  Here's the code:  Scanner keyboard = new Scanner(System.in);     String response1, response2;      System.out.println("Think of an object, and I'll try to "             + " guess it!");     System.out.print("1. Is it an animal, vegetable, or mineral?");     response1 = keyboard.next();      System.out.print("Is it bigger than a breadbox?");     response2 = keyboard.next();      if(response1 == "animal" && response2 == "yes")     {         System.out.println("You're thinking of a moose");     }     if(response1 == "animal" && response2 == "no")     {         System.out.println("You're thinking of a squirrel");     }     if(response1 == "vegetable" && response2 == "yes")     {         System.out.println("You're thinking of a watermelon");     }     if(response1 == "vegetable" && response2 == "no")     {         System.out.println("You're thinking of a carrot");     }     if(response1 == "mineral" && response2 == "yes")     {         System.out.println("You're thinking of a Camaro");     }     if(response1 == "mineral" && response2 == "no")     {         System.out.println("You're thinking of a paper clip");     }      System.out.println("I'd ask you if I'm right, but I don't really care");   Thanks in advance to any respondents!


Why is power transmission carried out at low current high voltage?

My textbook states that power is transmitted at high voltage and low current since $P=I^2R$ and as the current has a small magnitude, the heat dissipated across the transmission lines is less than when we carry it out at high current and low voltage. But $P=I^2R$ can also be written as $P=V^2/R$ and hence a discrepancy would occur. Where am I going wrong?


I have two aabbs and I need to know the collision normal of the to help me slide the aabbs across themselves. I have searched google but nothing really came up.   How do I get the collision normal of two aabbs colliding together


Store a file on server with curl command using post method like scp?

Like this:   cat tmp.txt | curl --post domain.com/file-to-store   I want to store content of tmp.txt on my machine to server using only terminal. Is it possible?


Virtualizing Windows and Ubuntu with Xen

Alright, so I'm constantly switching between Windows and Linux, and I'd love to be able to just switch whenever I need without a full reboot, and after a bit of research I came up with xen.  I found the community documentation , and it seems pretty straightforward, I just need to know if it will work for a normal desktop build as-is (from my limited understanding, the document seems to be aimed for servers), or if it needs a bit of modification.  Also, am I correct in thinking that I'll be able to boot both at the same time, and just switch between both Ubuntu (13.10 I think) and Windows 8? (With some performance impact)  On a side note, if somebody could also tell me (in the comments) if the amd fx-6300 is compatible with xen, that would be great. (It does support virtualization, but I know with intel, there is Vt-d and Vt-x, and I'm not sure if it matters with AMD though..)


How to register and use Azure in China from outside China?

I need to host a CMS website for an international company looking to expand into China.  The company has a registered entity in China, but we as the developer and support team responsible for provisioning and hosting the site, do not.  Our favored approach would be to host with Azure partners  azure.cn but there seems to be no registration or contact process for customers outside of China. Registration requires a Chinese phone number for verification.  Can anyone explain the registration process?


Am I reading enough of the scientific literature? Should I read for breadth or depth?

Ever since starting graduate school I've tried to make scientific reading a part of my daily ritual; I track pages read using , and the graph doesn't lie.  It keeps me honest.  I aim to closely read and summarize 5 pages per day and skim a few other abstracts besides that.  I spend about half my time looking at data and figures which doesn't contribute to my daily "page count."  When I'm reading about a new topic these five pages can take several hours, but on topics I have more background in five pages might only take an hour per day.  I guess since everybody defines "read" in a different way it's hard to get an objective answer about how much reading is enough.  How much people read seems like a bit of a sensitive topic among real-life colleagues because everyone has a bit of anxiety that they aren't reading enough.  But for those further along in their academic path, I'd like to hear how you approached the literature early in your graduate school career and what you think is a sufficient amount.  I guess this all distills down into two main topics:  When deciding what to read each day, should I focus on depth or breadth?  Is five pages of close reading per day enough?  I know it doesn't sound like much, but it takes significant mental energy to meet that goal.  And consistently reading 5 pages per day adds up to a lot over time.  Edited to add: I mostly read about petrology, volcanology, structural geology, and tectonics if that makes a difference.  By "page" I mean "page of text" so if I'm reading a structural geology paper with lots of maps and figures I discount for those and a "ten page" paper becomes a 5 page paper for my purposes.


All sites should be available when requesting closure with migration

I believe all sites should be available in the closure UI.  Then when a site is not actually available for automatic migration, other options should appear.  What appears will depend upon the site and/or why the site is not available for automatic migration.  (This question was added using the mobile site, and so without the benefit of suggested existing questions, or a preview.)  I originally thought this when a code-golf-like question was posted on Stack Overflow itself, and, accessing the site from a mobile, I wanted to quickly suggest that's where it should go. The current UI leaves you with a list of available migration sites and no further possibilities. You have to start over and try to choose the 'correct' option.


Does the electric field of a charged particle really contribute to its mass?

An electron at rest creates a static distribution of an electric field around it. Wherever the particle moves, it carries or drags the field with itself. Does this electric field contribute to the mass/inertia of the particle? A particle can have mass even if it does not have any electric charge. Does the presence of a field modifies its mass or inertia? Please do not give mechanical analogies.


OAuth 2.0 access token request failed with error "must use HTTP POST"

OAuth 2.0 Auth token request failed with below error   { "error": "invalid_request", "error_description": "must use HTTP POST" }   What does this error mean?  I am using Postman. Have a connected app. I have used Post method, Url has https. Same request works for other Orgs. Did I missed any configuration/Permission check?  https://testOrg.lightning.force.com/services/oauth2/token?grant_type=password&client_id={{CLIENT_ID}}&client_secret={{CLIENT_SECRET}}&username={{USER_ID}}&password={{PASSWORD}}


With the spell blink, could you deposit an object on the Ethereal plane?

Let's say you ready an action, that when you are on the ethereal plane you will drop your weapon. Does this work, would you return to the material plane without a weapon? Could you blink again and pick it back up later?     : ...you vanish from your current plane   of existence and appear in the Etheral Plane...   At the start of you next turn, and when the spell ends if you are on   the Etheral Plane, you return to an unoccupied space of your choice   that you can see within 10 feet of the space you vanished from.   A scenario where this could be very useful, imagine you are holding a ticking time bomb, you blink into the ethereal plane drop the bomb and blink back just in time, saving your party from the explosion.


Environment texture only shows when in camera view

When I'm the camera view mode, the environment texture shows up correctly, see:   However, when I'm controlling the viewport freely, the environment texture doesn't work at all but gets replaced by a random color:   I remember it used to not work this way, but I don't remember what I'm doing differently from before. The background settings I'm using are visible on the right of the picture. I'm also using Filmic blender.  Thanks in advance.


When we use Reference type and Object Type

I am having a doubt regarding ArrayList and List. In which case we should use ArraryList like:  ArrayList obj = new ArrayList();   And in which case we should use List Interface.  List obj =  new ArrayList();   What is the difference between them?


Are you allowed to post something non-question related?

I've been wondering if you are allowed to post something non-question related on Stack Exchange.   Like let’s say for example I want to share a cool new feature from an Android update. How would I go about posting it, or are you simply not allowed to post anything that is not a question?


I want to make a list of commands to install everything so it's easier the next time I do it, however, I wanted one of the commands to do CTRL+ALT+F1 for me.


How to detect perfect separation of logistic regression?

I have same error message as in this . However all my coefficients look normal with no inflated value or standard errors. My question is how can I make sure the error message is a sign of perfect separation or it's just some of my observations have extreme predicted probabilities?  Also, my model has Residual deviance=Inf and AIC=Inf, would they suggest that there is no perfect separation as they are measures of goodness of fit?


it's been 2 days since I bought the Apple Developer Program, and my account is pending:   About 10 minutes after the enrollment, I got an email, telling me that my purchase was being processed.  1 hour after I got this email, I got another email about the taxes, and there was a PDF attached to it.  I checked my account on Apple's website, but apparently, my account wasn't activated.  They say it should take 48 hours, but there is still nothing.  In addition to this post, I contacted  Developer support, they should answer me soon.  How long does it take for an account to be validated? Does it take longer if you're not in the U.S.?


How to install OS X 10.7 and 10.8 in VMWare Fusion, on a 10.9 host?

I'm working on fairly new Mac Mini, running OS X 10.9.4 and VMWare Fusion Pro 6.0.4.  For software testing purposes, I want to install both a OS X 10.7 Lion and OS X 10.8 Mountain Lion inside a virtual machine. I have access to the developer downloads under .    I can find numerous packages saying, for example "OS X Lion 10.7.2 Build XXXXX", but all of them seem to updates and are relatively small in size (~ 700 MB). I can't seem to find any image that would allow me to install a fresh 10.7 or 10.8 inside a new VM.  So how exactly do I go about creating those two virtual machines on my OS X 10.9 host?


I am trying to set alarm and notify user at the user's specified time. But I get NullPointerException at boundService.setAlarm(cal). I checked this  with a similar question but the solutions did not help me. Any help will be much appreciated.  Thanks a lot in advance!  DateAndTimePickerActivity  public class DateAndTimePickerActivity extends FragmentActivity implements     OnClickListener {     public Calendar cal;      private ScheduleClient scheduleClient;   @Override     protected void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     setContentView(R.layout.main);      scheduleClient = new ScheduleClient(this);     scheduleClient.doBindService();    }     @Override   private DatePickerDialog.OnDateSetListener mDateSetListener = new    DatePickerDialog.OnDateSetListener() {     public void onDateSet(DatePicker view, int yearSelected,             int monthOfYear, int dayOfMonth,int ) {         year = yearSelected;         month = monthOfYear;         day = dayOfMonth;      } }; private TimePickerDialog.OnTimeSetListener mTimeSetListener = new TimePickerDialog.OnTimeSetListener() {     // the callback received when the user "sets" the TimePickerDialog in     // the dialog     public void onTimeSet(TimePicker view, int hourOfDay, int min) {         hour = hourOfDay;         minute = min;         }         }; @Override public void onClick(View v) {       cal = Calendar.getInstance();         cal.set(year, month, day);         cal.set(Calendar.HOUR_OF_DAY, 0);         cal.set(Calendar.MINUTE, 0);         scheduleClient.setAlarmForNotification(cal); //NullPointerException   } }   ScheduleClient  public class ScheduleClient {  private ScheduleService boundService; private Context context;  private boolean isBound; RemindMe remindme; public ScheduleClient(Context context) {     super();     this.context = context; }  public void doBindService() {     // TODO Auto-generated method stub     context.bindService(new Intent(context,ScheduleService.class), Connection, Context.BIND_AUTO_CREATE);     isBound=true;  }  private ServiceConnection Connection = new ServiceConnection() {      @Override     public void onServiceConnected(ComponentName name, IBinder service) {         // TODO Auto-generated method stub         boundService=((ScheduleService.ServiceBinder) service).getService();      }      @Override     public void onServiceDisconnected(ComponentName name) {         // TODO Auto-generated method stub         boundService=null;      }   };    public void doUnbindService() {     // TODO Auto-generated method stub     if (isBound) {         // Detach our existing connection.         context.unbindService(Connection);         isBound = false;   }     }      public void setAlarmForNotification(Calendar cal) {       // TODO Auto-generated method stub        boundService.setAlarm(cal); //NullPointerException    }   }


I'm using Linux Mint. My login shell (cat /etc/passwd | grep myUserName) is bash.  After I start my graphical desktop environment and run a terminal emulator from it, I can see that .bash_profile is not sourced (environment vars that are exported in it are unset). But if I log in from a text console (ctrl+alt+F1) or manually run bash -l from the terminal emulator, .bash_profile works fine.  Am I wrong when I think that .bash_profile should be sourced when X starts and all export'ed vars should be available in the terminal, running from X?  P.S. Placing everything in .bashrc and sourcing it from .bash_profile is not good idea (): environment stuff should be sourced only once.


I got multiple entry schengen visa issued by Greece. Can I directly travel from India - Qatar - Romania or through schengen state

I got multiple entry schengen visa issued by Greece.. Can I directly travel from India - Qatar - Romania or should I have a stamping in schengen state?


How can I achieve the following:  type vdm in the terminal  and that will be replaced by wine Program Files/The VDM++ Toolbox Lite v8.3.1/bin  I also wanted vdm to work in any folder I am whatsoever.


Fermi's yield estimation of the Trinity Test

In Enrico Fermi's eyewitness account of the Trinity nuclear test in 1945, he gives a brief description of a method that he used to estimate the blast energy of the test:     About 40 seconds after the explosion the air blast reached me. I tried to estimate its strength by dropping from about six feet small pieces of paper before, during, and after the passage of the blast wave. Since, at the time, there was no wind I could observe very distinctly and actually measure the displacement of the pieces of paper that were in the process of falling while the blast was passing. The shift was about 2 1/2 meters, which, at the time, I estimated to correspond to the blast that would be produced by ten thousand tons of T.N.T. - c.f.  via wikipedia.   Given the information provided in the above statement, is it possible to derive his estimate of 10kT T.N.T equivalent?


Listing classpath throws NullPointerException

I have used following code to print the classpath from inside of jar (build with intelliJ):      URL[] urls = ((URLClassLoader) ClassLoader.getSystemClassLoader()).getURLs();     for (URL url : urls) {         System.out.println(url);     }   However this throws NullPointerException. What am I doing wrong?


Am I correct to say the difference between a signed and unsigned integer is:  Unsigned can hold a larger positive value and no negative value. Unsigned uses the leading bit as a part of the value, while the signed version uses the left-most-bit to identify if the number is positive or negative. Signed integers can hold both positive and negative numbers.  Any other differences?


If I am writing a letter and I use an office title for the first time, I will include the acronym, but if the office title has a possessive, apostrophe s, will the acronym have the apostrophe s within the parenthesis, outside the parenthesis, or not at all? Examples:  Maintain oversight functions over U.S. Customs and Border Protection’s (CBP)’s $13.6B budget. Maintain oversight functions over U.S. Customs and Border Protection’s (CBP's) $13.6B budget. Maintain oversight functions over U.S. Customs and Border Protection’s (CBP) $13.6B budget.


Sorry for the zero-intelligence question, but how do I load a package in a Plain TeX document? (No LaTeX please.) Specifically, I'd like to load the amsfonts package such as to have access to the \mathbb fonts. I'm using pdftex from the command line, on a mac.


How to use a tikz image as label in enumerate?

Is there a way to use a TikZ image as a label of enumerate?  Can I use something like the snippet below as a "styled enumeration"?  \newcommand\custlabel[1]{ \begin{tikzpicture}     \node[circle, fill=blue] (A) {#1}; \end{tikzpicture} }


Denumerable partition of a denumerable set where each set in the partition is denumerable.

Suppose that a set $A$ is denumerable. Prove that there is a partition $P$ of $A$ where $P$ is denumerable and every $X \in P$ is also denumerable.  I can see that this can be done but I cannot figure out how to construct it where every $X \in P$ is denumerable and not finite. Any ideas here?


How do you convert date to MM/DD HH/MM  example: 04-05 12:42


Breakthrough at the Large Hadron Collider -Leptoquarks skepticism?

I have came across this recent development in the LHC: Breakthrough at the Large Hadron Collider:  Leptoquarks and leptons - quarks unification:   Leptoquarks (LQs) are hypothetical particles that would interact with quarks and leptons. Leptoquarks are color-triplet bosons that carry both lepton and baryon numbers. Their other quantum numbers, like spin, (fractional) electric charge and weak isospin vary among theories.  Does this mean that we are heading for a strong-EM forces unification? Is the Electron after all coupled to the individual quarks in the nucleus via these new boson? And therefore new unifying force discovered?


What if I just opened my bank account this month, and I'm planning to travel to the UK in December and visit my family for six months? Is it possible to get a  visa if I present that bank statement  which was open just recently?  Since this will be my last year in school, and I'm not employed, I am just a working part-time working at my Dad's workplace, and I receive my pay on a daily basis since I'm a casual worker without a payslip. Is there any other supporting document apart from my employer or school to offer for my UK visa application as supporting documents?


file1.cc  void func() {   std::cout << "test\n"; }   file2.cc  ... std::string str = GET_FILE("file1.cc"); ...   So, what I need is that str has the content of file1.cc as string, in compile time, NOT execution time.  How to implement this GET_FILE macro?


Is "more easy" a correct grammatical way of saying "easier"? What other ways can you express the word "easier"?


Tag info not updated regularly on profile?

From my , I learned that all tag related info on profile will be updated daily at UTC 03:00.  However, something is wrong here. It's now UTC 05:00+, but my tag number, say 93 (c++) is not updated against yesterday. I am pretty sure about this and I did earn some more points throughout the day. Sorry for not be able to capture the screenshot yesterday, but I did check this number 10 hours ago (which belongs to yesterday, also 93).  Is there a bug happening here? Or updating time different?    UPDATE: As of 24 Jan, the tags are still not updated with the proper values.  UPDATE2: Fixed around 25 Jan, UTC 03:00, at least for me.


How to calculate the following: $\sum_{n=0}^\infty \frac{1}{1+n^2}=\;\;?$

How can I calculate the following sum?  any hint please? I am beginner in such things, i have tried to make a decomposition for the denominator but no result $$\sum_{n=0}^\infty \frac{1}{1+n^2}=?$$


I am looking to modify the default output of Drupal 8 of links in a certain situation, the language switcher. Ideally I want to be able to do that in a twig template and not have to produce a  that overwwrites that whole link generation system and add a BIG if for the cases I need to overwrite.  I think the output layout should be controllable in the twig template similar to  (this answer outputs the same url for every languages)  I am using bootstrap as a base theme so i'd like to use the bootstrap markup for my links (btn btn-primary, dropdown)  Here is my code I am trying to make links--language-block.html.twig  {%- if links|length == 2 -%}     {# show only alternate language button #}     {%- for key, item in links -%}         {%- if not item.attributes['#options']['set_active_class'] -%} {# <--- this is always true!? #}             {{ item.link['#title'] }} {# #url is always the same what ever the language it is pointing to! #}         {%- endif -%}     {%- endfor -%} {%- elseif links|length > 2  -%}     {# show selected language in button and other languages in drop down #}     <button class="btn btn-primary dropdown-toggle" type="button" data-toggle="dropdown">{{ selectedLanguage }}</button>
         {% for key, item in links %}             {%- if not item.attributes['#options']['set_active_class'] -%} {# <--- this is always true!? #}
{{ item.link['#title'] }}
             {% endif %}         {% endfor %}
 {%- endif -%}   Anyone has an idea on how to do this?


Merging seemingly contiguous polygons leaves artifacts

I am working with a  country vector dataset () and I am trying to merge country polygons according to custom regions (based on the UN Geoscheme), in order to only have an outer border rather than every single country's border.  My issue is that, seemingly contiguous countries leave artefacts after merging, be it by hand ("edit > merge selected features") or by using the "dissolve" tool ("vector > geoprocessing tools > dissolve").  How come there are stray lines inside the regions? Can I somehow fix that, or should I find a different dataset?  See the following examples in Africa:  Merging by hand    Dissolving according to data


Is it considered appropriate to upvote my friend if I find their posts useful?

Say a specific user is my friend. Naturally, I follow the user's activity and each time he/she posts an answer, I upvote it. Of course I do that only after a careful read and if I find it useful, at least for the OP.  Is it considered inappropriate? Would some automatic algorithm track my upvoting activity and cancel it?  And what if that friend also gives me the same attention?  Again, I don't mean . The relation just attracts attention to the user's activity which is followed by probable upvote (as that friend is by all means no less than the ultimate professional).


US to INDIA via Zurich, Do I need transit visa?

I am an Indian Passport holder, traveling from Chicago to New Delhi INDIA with Layover in Zurich of 2 hours. My US Visa is expired which is why I am traveling back to get the new visa stamped. Will I also need a Transit visa for Zurich? I have all the visa documents to show the approval through which stamping will be done in INDIA.


I haven't been able to find my favorite questions in the official Stack Exchange Android app.  Looking at my accounts page gives nothing on them.


In arm assembly, is the stack a separate memory unit or a partition of the main memory?

I always have this confusion,in arm assembly, is the stack a separate memory unit or a partition of the main memory itself? In my understanding,the main memory(RAM) is divided into stack and heap.The stack is pointed by the stack pointer R13 register or sp.From this pointer we can do the stack operations. Also what I understand is that stack stores local variables in high level languages and function calls.How does it translate to assembly? I am not able to find the answers to these questions on google.


In the video, , a guy says:     I wasn't much of a big brother.   Isn't it incorrect to say? I think it should be elder brother.


Is it possible when you know some n calculate the x if   $$n = x^x$$  ?  Sorry, I did't even know how this equation is called, any help appreciate.


How should we approach the authors of a paper and ask them for their data?

Nowadays, many papers are based on data that can easily reach several Gigas. It is understandable that these data are not incorporated into the work, nor are hosted with the publisher. What is the more acceptable way of asking them to access this data? Call + email? Email to the publishers? Making a Freedom of information request to the university?


How to run a 0.05A fan with a 10A source?

I am constructing a circuit to drive a powerful LED that requires about 10 amps at 12V.  I also have a battery that happily supplies that.  For obvious reasons, that LED requires a cooling fan, and I've chosen one that takes 0.05 amps at 12V.  How can I run this fan with the existing circuit?  EDIT:  I will probably be using a boost converter to control the current. It will be boosting from ~10V to the 12V required for the LED. I will also be using it to dim the LED.  Specifications for the boost converter:   Input: 8.5-50V, 15A max Output: 10-60V, 12A max


Are there any known negative heat capacities?

If we take heat capacity to be defined as "the ratio of the heat added to the temperature rise":  $$ C=\frac{\text{d} Q_{rev}}{\text{d}\theta}$$  then this leads me to ask:  can this ever be negative? That is to say, are there any materials which cool as you add heat to them?


How does bash print to the screen if not with a framebuffer?

I noticed that a framebuffer doesn't always exist on some systems. In these cases, how does bash print to the screen (assuming it ever uses fb devices at all)? Since there's no framebuffer device, does this mean that bash knows how every graphics card out there works and can directly write to their registers, or does it use some other API?


Python - How to check PEP8 errors in a chunk of code with no specific file

I'm currently working in an eLearning platform, and I'm trying to add some PEP8 validation to the assignment solutions students are submitting to the system in order to give then some extra feedback about how good or bad the solution they proposed is.  I found that using the python pep8 package it's not that simple to check PEP8 errors just in a chunk of code (in my case, it would be the posted solution to the assignment), without specifying any path to a specific file in the filesystem.  Is it actually possible or the pep8 library doesn't allow it? Of course I could save the posted solution in a tmp file and run the validation from there, but I would like to avoid this extra step.  Did anyone have the same issue?


Is "The crowd are loving this.", from a UK newspaper, acceptable?

Is "The crowd are loving this." acceptable grammar? I think it should be "The crowd is loving this."  Does it matter if it's a UK newspaper?


Is it okay to board only the second flight of a return ticket? The return ticket is much cheaper than buying one way

I was browsing flight price at Singapore Airlines website, and a one-way flight from SIN to SFO cost this much:    That's quite expensive. I tried browsing around and found that a return flight from SFO to SIN and back to SFO cost much cheaper:    It's really weird because the second ticket includes the exact same flight that cost 1900+, but it's almost half the price. The reason for this counter-intuitive situation is explained in the answers this question   If I am located in Singapore and my intention is to fly one-way to SFO, is it safe to book the flight in the second picture and only board SFO-SIN leg? Will they deny me because I miss the SIN-SFO flight?


Round a double value to 10 digits in Java?

I was looking for a simple way to round a double value to 10 digits but I didn't found even one way that look good to me, everything was too complicated.  I hope someone could help me, for example: the value 0.83426945721236485 will become 0.8342694572  Thank you in advance.


Neural network hyperparameters don't affect performance

I am trying to perform multi-label classification using neural network, with 3 hidden ReLU layers and a softmax output layer. I'm also using mini-batch SGD as the optimization algorithm and negative log likelihood as the loss function with L2 regularization. After performing feature scaling this is what I'm noticing is the following:    Algorithm performance plateaus in terms of validation and test error very early during training Virtually no hyperparameter other than mini-batch size factors into the algorithm's performance even if I choose seemingly absurd values (e.g learning rate, number of hidden units, L2 reg coefficient) I'm getting better performance in the non-scaled version of the data set, rather than the scaled one.   Especially bothersome for me is the second point, as I cannot explain it at all. Surely, the learning rate or the number of units in the hidden layers should affect performance even slightly, however that's not what I'm seeing. If anyone has any pointers for explaining and even rectifying the situation I would be really grateful.  Thanks in advance.


Which are the effects of removing sugars from a balanced diet for an otherwise healthy person

What effects would removing sugars from a balanced diet have on an otherwise healthy person have? I've heard that both refined and natural sugars can have a negative impact in the body. Is it safe to stop consuming sugars all together?


What version of windows can be virtualized?

I have an Ubuntu machine that I want to have windows virtualized in with VirtualBox.  Is there a specific version of Windows 7 that I have to have so that the license will allow me to virtualize it?


I clicked on the "Link my next chat message as a reply to this" arrow after a comment (as shown here):        and when I did, I got this in my chat window:       so I then clicked on the upload button, selected a picture from my computer, and clicked on the upload button.    However, when my picture posted, it did not show as being linked to the original comment. Any ideas?


How can be explained the phenomenon of two related Gamma rays ending their courses by becoming an electron and a positron without the involvement of a photon and an anti-photon ? This question must be understood as "How can we explain the said phenomenon ?".  I am an autodidacte in Physics. I have developed a theory about the Universe that will be edited soon on YouScribe. It is based on the Ockham principle of simplicity and results in a full explanation without mysteries nor any unexplained subjects. And so, what is it worth ?


Showing one row of a matrix in two lines


Why are two people allowed to open the edit page at the same time?

I edited a question and went to submit it when I was presented with this warning, is there a reason the other person was still allowed to open the edit page even though I was editing it?     Another edit is awaiting approval for this post. Further edits cannot be submitted until the pending edit is reviewed.   I'm not asking why my edit got rejected or why edits aren't being merged, I just want to know if there's a reason two people are allowed to open the edit window at the same time and the second blocked from opening it.


I am using HP Compaq 6735b laptop and it comes with a ATI Mobility Radeon HD 3200 Graphics card. I have recently installed 12.04 on it.   Can someone tell me how will I know if the Graphics card is working or not?


This code:  \documentclass[a4paper,twoside,12pt]{scrreprt} \usepackage{fontspec} \begin{document} Test \scalebox{3.0}{$\int$} test. \begin{table}   \centering \begin{tabular}{cc}   A & B \\   C & D  \end{tabular} \caption{Test \scalebox{3.0}{$\int$} test.} \end{table} \end{document}   gives me the error message:  ! Argument of \@caption has an extra }.   The result looks how I want it to, though...  What should I do?


Why do we restrict the definition of Lebesgue Integrability?

The function $f(x) = \sin(x)/x$ is Riemann Integrable from $0$ to $\infty$, but it is not Lebesgue Integrable on that same interval.  (Note, it is not absolutely Riemann Integrable.)  Why is it we restrict our definition of Lebesgue Integrability to absolutely integrable?  Wouldn't it be better to extend our definition to include ALL cases where Riemann Integrability holds, and use the current definition as a corollary for when the improper integral is absolutely integrable?


How to identify the font family name from latex font catalogue

I want to change the font in my different paragraphs.  for that I am using this commands,  \fontfamily{font-family-name}\selectfont  in some cases I am defining an environment for the font and  I am using.  Question:  Eventhough I can find the good fonts installed in my texlive from the latex catalogue expecially   I couldnot find the font family name.. to use that font.  How to do that.??


Why does this work:  $n = explode("@", "some@email.com"); echo $n[0];   And this not work?  explode("@", "some@email.com")[0]   When I try the latter, I get:  Parse error: syntax error, unexpected '['


How to remove blank spaces in line with regex?

I have file like below.,   23,1:30 - 2:00,10,,,,   23,1:30 - 2:00,600,,,,     23,1:30 - 2:00,600,,,, 23,1:2 - 23:00,321,,,,   Now i need to remove the blank spaces in whole file and replace it with empty.  I have already tried with This regex  for search \ s+ and replace with \n it doesn't work  So i have need search and replacement value for find blank spaces and replace it with empty like below output.  23,1:30 - 2:00,10,,,, 23,1:30 - 2:00,600,,,, 23,1:30 - 2:00,600,,,, 23,1:2 - 23:00,321,,,,   And finally need search and replacement value for ReplaceText processor which perform my requirements.


Is energy fundamentally the will of the universe?


I'm pretty much a newbie with UNIX and I m having a bit of a difficulty connecting my Ubuntu PC with my Windows 7 PC via LAN.   First things first, I've installed samba and created a shared folder both via CLI and GUI and everything seams to be working.  On my windows PC I've set up all the network settings as they should be in Control Panel -> Network and Sharing center -> Advanced sharing settings.  Network sharing is working with my windows laptop and my Windows desktop but the Ubuntu laptop is not visible in my network list and my Windows pc's cant see my Ubuntu laptop on network either.   I'll upload my smb.config file once I get in my Ubuntu laptop so you guys can see that as well i just wrote this first in case i'm forgetting to do something to make this work.  And yes, both my Windows PC's and Ubuntu PC are in the same workgroup.


Do Temporary Hit Points confer some form of protection?

I have been thinking that temporary hit points were like virtual health as per:     Temporary hit points aren’t actual hit points; they are a buffer against damage, a pool of hit points that protect you from injury.   The fact that's virtual makes me think that you don't actually get hit per se. That is, you'd get out without even a scratch if you only lose temporary hit points (i.e. protect you from injury).  However, I have not seen anything anywhere saying that if you are bitten by a creature such as a spider and only lose temporary hit points, you don't get poisoned. Yet, if you don't even sustain a scratch, how could you get poisoned or paralyzed or sick?  How do you guys understand the rules in such circumstances?


One-off bug in reputation graph (bar chart)

I found a possible bug in the reputation graph, i.e. the bar chart, showing reputation for each single day (go to user profile -> activity -> reputation -> graph). Actually, there seem to be two bugs, but those are probably closely related:   all of the bars are one-off: the "half bar" for the current day shown the correct reputation, but the tool-tip shows the date of the previous day, and accordingly for all other days when I click the bar, the reputation breakdown below the chart shows the reputation for the previous day (i.e. the same day as in the tool-tip)   In other words, for each single day,   the height of the bar is correct the reputation shown in the tool-tip is correct the date in the tool tip is the date of the previous day the reputation shown below the graph is that of the previous day   I searched for related questions, and the bug seems to be the same as  and , but those are 5 years old and reportedly fixed. Also, I can't remember experiencing this bug some time ago, so if this is the same bug, it must have reappeared.  Using Firefox 44.0.2 on Xubuntu 14.04, in case it matters.


Can I install Ubuntu on an exFAT hard drive?

I would like to know if it's possible to install Ubuntu on an exFAT hard drive, since Windows 8's drive admin utility only allow me to get NTFS and exFAT partitions.  Thanks in advance.


How to play with each other on Minecraft PE with iOS? (Minecraft Version 0.7.5)

I would like to play with my friend on Minecraft PE, but when we connect to the same network, I can't detect his world when he opens his world, and he can't find my world on LAN when I open my world. Does it have to do with the firewall. I went to another friends house and connected to their network and it worked! So what should I do?


I want to make my script wait for n seconds, during which user can abort the script. My code till now looks like this   echo "Start Date provided :" $STARTDATE echo "End date provided :" $ENDDATE echo "" echo "Please check the dates provided and in case of error press CTRL+C" seq 1 15 |while read i; do echo -ne "\rWaiting for $i seconds"; sleep 1; done echo "" echo "Executing query on the remote side, please wait..."   When the user presses ctrl+c though what happens is that the while loop ends and continues executing the rest of the script.   How can I make it abort the entire script? Thanks in advance for any advise


Show that the following set is connected subset of $\mathbb R^2$ :  $$\left\{\left(x,\sin \frac{1}{x}\right)\in \mathbb R^2|0<x<\infty\right\}\cup\left\{(0,0)\right\}$$  Attempt : Here  $A=\left\{\left(x,\sin \frac{1}{x}\right)\in \mathbb R^2|0<x<\infty\right\}$ is connected as, $f:(0,\infty) \to \mathbb R^2$ defined by $f(x)=\left(x,\sin \frac{1}{x}\right)$  is continuous and $(0,\infty)$ is connected. Again $B=\{(0,0)\}$ is also connected. $A\cap B=\emptyset$. So how can I prove that $A\cup B$ is connected ?  If $A$ and $B$ are connected and $A\cap B\not=\emptyset$ then $A\cup B$ is also connected. But it is a sufficient condition. So I can't conclude that $A\cup B$ is disconnected.


explain the difference between /bin and /usr/bin used in Linux?


Is improving an answer (from incomplete to complete) a "change in meaning"?

So I've just tried to edit an answer for the first time, here:   Rejected three to two. I'm not really trying to 'fight the decision'. I mean, I don't really have a stake in this.  But I'm kind of confused by the (canned?) response:     This edit changes too much in the original post; the original meaning or intent of the post would be lost.   Lets start with intent. Surely this was:   To attempt to provide an alternate answer the question, by means of dropping to shell and invoking POSIX-standard command. (Which happens to be command in this case).   So I really don't think the edit changes 'intent'.  As for meaning, well yes, it does change the meaning - it changes it from something that doesn't work - but only just quite - to something that does, essentially by prefixing four characters and adding a set of quotes. If this is why it was rejected, it would seem to me to fly in the face of:    (second response, not re: "constantly").    This was effectively the basis on which I was justifying the edit, as it isn't remotely close to this situation:     So: if anyone could clarify this for me, it would be appreciated. What's best practice to follow at this point?  Comment? New answer?    (I assume its kind of bad form to say "I tried editing this, but it was rejected, so..." But honestly I'd kind of like to do so, since I really don't think it needs a new answer, or commentary.)


Find number of d's that satisfies $d, d+1, d+2... = N$ for an $N$

I have a challenge about a cat in a trip where he can walk in the way of $d, d+1, d+2...$ and the sum of that should give $N$, given an $N$, how many ways of chosing $d$ are posible?  Example:  $N=30$ -> $Ans=3$  $d_1=4; d_2=6; d_3=8$   For $d_1: 4 + 5 + 6 + 7 + 8 = 30$  Edit:  Another way to see it is: How many subsets in the sumation up to N are posible in the way $(\sum (d+n) - \sum(d-1))$=N


The following C++ Code relate to pointer and reference

I have seen this code    void path(     const char * p);   » more...  void path(     const std::string & p);   » more...   Can I do the following modification, basically reversing the * and &.  void path(     const char & p);   » more...  void path(     const std::string * p);   » more...


Please solve this doubt : we know that  $\sqrt{a}\sqrt{b}=\sqrt{ab}$ and $i^2 = -1$. But $i= \sqrt{-1}$ which implies that $i^2 = i \cdot i = \sqrt{-1}\sqrt{-1} = \sqrt{1} = 1$ that is $i^2 = 1$. So what is the correct value of $i^2$? Is it $1$ or is it $-1$? Please explain.


I'm trying to write a function that returns:  ['cat', 'cot', 'cut']   When passed this list:  ['c', 'aou', 't']   But would also return:  ['cats', 'catz', 'cots', 'cotz', 'cuts', 'cutz']   When passed:  ['c', 'aou', 't', 'sz']


Really struggling to dual boot windows and ubuntu

I need access to docker which I cannot get on windows because for some reason version 2004 is not yet available for me (I checked for updates in settings) so I am trying to dual boot from usb. I have created a live USB with ubuntu, I made it bootable then tried to boot from usb and it brought up gnu grub. I selected ubuntu and then my PC just keeps powering off while "checking disk". I now formatted my usb as ext4 and it is no longer visible in my PC so I don't know how to move ubuntu to the USB. Is there a straight forward way to get this done?? It has been a nightmare so far I don't know what to do anymore.


I've been reading about this everywhere all day, and from what I've gathered, TIME_WAIT is a relatively harmless state. It's supposed to be harmless even when there's too many.  But if they're jumping to the numbers I've been seeing for the past 24 hours, something is really wrong!  [root@1 ~]# netstat -nat | awk '{print $6}' | sort | uniq -c | sort -n   1 established)   1 Foreign  12 CLOSE_WAIT  15 LISTEN  64 LAST_ACK 201 FIN_WAIT2 334 CLOSING 605 ESTABLISHED 816 SYN_RECV 981 FIN_WAIT1 26830 TIME_WAIT   That number fluctuates from 20,000 to 30,000+ (so far, the maximum I've seen it go is 32,000). What worries me is that they're all different IP addresses from all sorts of random locations.  Now this is supposed to be (or was supposed to be) a DDoS attack. I know this for a fact, but I won't go into the boring details. It started out as a DDoS and it did impact my server's performance for a couple minutes. After that, everything was back to normal. My server load is normal. My internet traffic is normal. No server resource is being abused. My sites load fine.  I also have IPTABLES disabled. There's an odd issue with that too. Every time I enable the firewall/iptables, my server starts experiencing packet loss. Lots of it. About 50%-60% packets are lost. It happens within an hour or within a few hours of enabling the firewall. As soon as I disable it, ping responses from all locations I test them from start clearing up and get stable again. Very strange.  The TIME_WAIT state connections have been fluctuating at those numbers since yesterday. For 24 hours now, I've had that, and although it hasn't impacted performance in any way, it's disturbing enough.  My current tcp_fin_timeout value is 30 seconds, from the default 60 seconds. However, that seems to not help, at all.  Any ideas, suggestions? Anything at all would be appreciated, really!


Finding the joint density of two independent exponential distributions

Let $X_1,X_2$ be independent random variables each having a exponential distribution with mean $λ = 1$.   (a) Find the joint density of $Y_1 = X_1$ and $Y_2 = X_1 + X_2$.  (b) Get the marginal density of $f_{Y_1}(y_1)$ and $f_{Y_2}(y_2)$.  These are what I've found so far.  $$f_{X_1}(x_1)=e^{-x_1}, f_{X_2}(x_2)=e^{-x_2}$$ $$f_{X_1,X_2}(x_1, x_2)=f_{X_1}(x_1)f_{X_2}(x_2)=e^{-x_1-x_2}$$  Also, since $Y_1=X1$, $f_{Y_1}(y_1)=e^{-y_1}$ right? Similarly, since $Y_2=X_1+X_2$, $f_{Y_2}(y_2)=e^{-y_2}$  However, is it guaranteed that $Y_1$ and $Y_2$ are independent? or else how can I solve these problems??  Oh, and I haven't learned the Jacobian so it would be grateful if you avoid using it.


I installed Windows 8 and Ubuntu 12.10 on a 3TB GPT disk in UEFI mode.  Both can boot up OK.  Both operating systems created their ntries in the UEFI boot menu, there's an "ubuntu" and a "Windows 8" entry.  The boot order can be altered in the motherboard's UEFI setup.  I'd like to boot "ubuntu" first, because I set up GRUB 2 to be able to boot both systems.  But whenever I boot Windows 8, it changes the boot order so that it boots up first.  How can I prevent this?  Thanks a lot.  -- UPDATE --  I learned that bcdedit.exe can be used to manipulate the Boot Configuration Data in windows.  This is important because Windows synchronizes the BCD with the boot NVRAM, that stores the boot order.  Every time the {fwbootmgr} entry in the BCD is touched, the NVRAM is overwritten.  I modified this entry to load GRUB 2 first, and it did. However, after booting Windows 8, both the NVRAM and the {fwbootmgr} in the BCD reverted to the original order, that is, to boot Windows 8 first.  I'm really puzzled by this.  -- UPDATE 2 --  I managed to kinda fix the problem by creating a startup script at the group policy editor in Windows. The startup script issues a "bcdedit /set {fwbootmgr} DEFAULT {appropriate UUID}" command. This is BIG hack, and definitely NOT the soulution I want. I'd like Windows to feel OK at the second place after GRUB in the NVRAM.  So how can I do that?


How can I get a .MTL file to show on an .OBJ model I imported in Cycles?

I've downloaded & imported several .OBJ models into Blender but they don't always import with the textures automatically in place, even though the model came with them. Here's an example:   I assume this is due to the presence of an .MTL file, but I don't know for sure.


Is "chutzpah" used by non-Jewish English speakers?

Chutzpah is a term common to both Hebrew and Yiddish, and has been imported into English, at least for Jews. It means approximately audacity, nerve, insolence.  Is chutzpah also used by non-Jewish English speakers?  I think I have only seen it once outside of Jewish publications / communities.


Is "cant" a spelling or grammar mistake?   I know using "where" instead of "were" and similar mistakes are grammatical errors. But is using "cant" instead of "can't"? Why is it one rather than the other?  Many thanks.  EDIT: I was not aware when writing this that "cant" was a word on it's own. My question is that if it weren't would the mistake be spelling or grammar. For example if you write down "werent" instead of "weren't".


Is there a name for a word pronounced the same backwards as forwards?

I find it very interesting that Judge /dʒʌdʒ/ is pronounced the same backwards as forwards while it is not a palindrome. Does this phenomenon have a name?


How to evaluate  $$  \int_0^\infty \frac{\sin(\varphi_1x)}{x}\frac{\sin\varphi_2x}{x} \cdots \frac{\sin\varphi_nx}{x} \frac{\sin(ax)}{x}\cos(a_1x) \cdots \cos(a_mx) \, dx  \text{ ?} $$  For small $n$ and $m$ it's simple (setting $\sin(kx)=\dfrac{e^{ikx}-e^{-ikx}}{2i}$ and using Jordan's lemma, but for arbitrary $n$ the calculation is too tedious. Surely there must be some nice trick here? Thanks


I've got a new pc yesterday, installed 14.04lts and had some problems with my graphics card driver (now fixed I believe). Now I've tried installing steam through various methods and can't get it to work. Any help would be greatly appreciated! Gtx 950 i7 4790k


How can I reduce a PDF size that is very big locally in a Mac


Making round features on cubes in hard surface modelling

Rather than just blindly following Youtube tutorials, I like to practice modelling by finding concept art I like and trying to model it in Blender. In this case I'm trying to model this robot:  I'm trying to replicate that big round lens in the robot's 'head', but I can't seem to do it and still have clean geometry. I have tried using a boolean to cut out the circle, then adding a sphere, but it results in a messy mesh.  There are no doubt several better ways to achieve the same effect with much cleaner results. Any ideas?


I am using Ubuntu Budgie 18.04.4  I was fiddling with the Login Window and lightdm-gtk-greeter-settings apps in an attempt to change the background in lightdm. However a side-effect appears to be that I have lost the slick greeter with the nice transparent login box.  Does anybody have any idea how to get it back?


I am very new to QGIS for the primary purpose of creating a slopes layer so we know where slopes are above 15% or 20% or whatever we finally decide.  I have used our DEM to create a slope geotif and have used that to try and create a classified layer, but that is where my problems seem to begin. I used this formula to create my classified layer ((slope@1 < 15) OR (slope@1 > 60)) = 0 and while I get a new layer I am not able to view it, no matter how I manipulate the properites. I also tried to follow the  for the display that says to do this:      9.4.16. Setting the style for the reclassified layers         Open the Style tab in the layer’s Properties dialog as usual.   Under the heading Load min / max values from band, select the Actual    (slower) radio button.   Click the Load button.         The Custom min / max values fields should now populate with 0 and 1,   respectively. (If they do not, then there was a mistake with your   reclassification of the data, and you will need to go over that part   again.)         Under the heading Contrast enhancement, set the Current dropdown list    to Stretch To MinMax.   Click OK.      I do not come up with the 0 and 1 that the instructions speak of (I am not using their tutorial data) but it seems that I should be able to see the layer.


Does light change color on its way through a window?

Looking at the refractive index of glass, it's around $1.6$.  Then the speed of light $x$ through light should be given by $$ 1.6 = \frac{3.0\times10^8}{x}, $$ so $x$ is about $2\times10^8~\mathrm{m}~\mathrm{s}^{-1}$  The frequency is kept constant, so the wavelength must adapt to suit the slower speed, giving a wavelength of $2/3$ the original.  Does this mean that when passing through glass, say red light (wavelength $650~\mathrm{nm}$) changes to indigo ($445~\mathrm{nm}$), as $650 \times 2/3 = 433~\mathrm{nm}$, or is my logic flawed somewhere?


recently I have install  Ubuntu 13.04 removing windows 7 . before installing Ubuntu in win 7 there are 5 partition storing my  important data but after installing  Ubuntu all partition merged into single one and delete my all earlier data but I want to get back my those all data please give me useful information to help


Is there a keyboard shortcut to bring up Finder?

Is there a default keyboard shortcut to start a new Finder window? If not, is there a way to assign one?  I tried System Preferences > Keyboard > Shortcuts > App Shortcuts and created a new item for Finder, and assigned shift-command ⌘-F, among other things, but nothing worked.


MySQL stop/waiting issues; “can't connect … through socket”

So this was my first time putting up a LAMP stack on a Bodhi machine (previously experience with WAMP, and LAMP on 10.04); I got Apache going, and a Drupal install begun, then I go to create a new database and when I log in to phpmyadmin ... I get a 'cannot connect error'. Tracing this back, the issue began once I tried to get virtual hosts up and running in Apache; once that was done I started running into socket connection issues with mysql.   Initially the problem looked like this:  ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)  Using ls -lart /var/run/my* I get this:    total 0   drwxr-xr-x  2 mysql root  40 Jan 31 11:56 .   drwxr-xr-x 21 root  root 740 Jan 31 12:21 ..`   I ran touch /var/run/mysqld/mysqld.sock and set chown -R mysql /var/run/mysqld which allows for:  total 0 drwxr-xr-x 21 root  root 740 Jan 31 12:21 .. -rw-r--r--  1 mysql root   0 Jan 31 13:58 mysqld.sock drwxr-xr-x  2 mysql root  60 Jan 31 13:58 .    So when I try to run mysql -u root -p I get one error - ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (13) (note it is no longer ERROR 2002...(2) but rather ERROR 2002...(13)) If I try service mysql restart (or stop, start) I get another error - start: Rejected send message, 1 matched rules; type="method_call", sender=":1.49" (uid=1000 pid=8407 comm="start mysql ") interface="com.ubuntu.Upstart0_6.Job" member="Start" error name="(unset)" requested_reply="0" destination="com.ubuntu.Upstart" (uid=0 pid=1 comm="/sbin/init")  When I run sudo service mysql restart I get stop: Unknown instance:  start: Job failed to start  When I run service mysql status I get "mysql stop/waiting"   What can I do to diagnose the issues I am having with mysql? I may be overlooking an utterly simple mysql issue and would appreciate any feedback on what I've done so far.  Also, being a Bodhi machine and most of the instruction/feedback being written for Ubuntu, I am unsure to what extent any Ubuntu instruction may not apply. In particular, am I running into a problem related to the difference between /etc/init.d/... and service ... ... commands? Or, perhaps, am I running into a difference between libraries of the two?


Good afternoon. I Have a problem with this proof:     Let $B$ the set of limit points of $A$. Prove $B$ is a closed set.   I try to make this:  Suppose $B$ is not a closed set. Then exist a $B ∩B(x;r)=Ø$  where $r>0$. Suppose $A ⊆ B$ and $x$ a limit point of $A$ Then $x$ is a limit point of $B$. Contradiction.  Please, help me, i don't know if this is fine.


I came across the following problem and do not know how to tackle it.       Find the last two digits of $ 7^{81} ?$     Can someone point me in the right direction? Thanks in advance for your time.


Find out which Internet sources are addressed by an app on iOS

I want to set up a whitelist in a router and I need to know what Internet addresses are consulted by a specific app on iPhone or iPad.  Are there tools for this?


Find integers $a$ and $b$ such that $a^5b+3$ and $ab^5+3$ are both perfect cubes of integers?

Are there integers $a$ and $b$ such that $a^5b+3$ and $ab^5+3$ are both perfect cubes of integers? $a,b$ are distinct integers.  P.S.: I think trying to find some special cases would not be helpful.


Email Regex validation in JavaScript allowing characters (#$%&* etc) in middle

Email format is like : local_part @ domain_part.com          Local_part & domain_part should not begin or end with special characters ( @#&()*,./{}<>^%[]~`!$=\|;:? ) including hyphen (-)          Local_part & domain_part may contain above special characters like (#$%&*- etc) in middle only.           Limit of lengths for local_part is 64 & domain_part is 255 characters respectively.          domain_part must not contain all numbers


Would it be useful to convert NTFS to EXT4 with this system setup?

Consider the following system:  Distribution: Devuan Beowulf. DRAM Memory: 16 GB. Linux kernel version: 5.10.0. Secondary storage: One SDD and one HDD. Used as a desktop, including software development which can be taxing on system resources in itself. The SSD has a boot partition P1, a large partition P2 mounted as /. The HDD has a single large partition P3, with different paths in / symlinked to place within it (e.g. /home or /home/someuser, and perhaps some paths under /var etc.) It is in heavy use.  How important/beneficial is it for partition P3 to be ext4 rather than NTFS? Bonus question: Should another filesystem be considered for P3?


If angular velocity & angular acceleration are vectors, why not angular displacement?

Are angular quantities vector?   ... It is not easy to get used to representing angular quantities as vectors. We instinctively expect that something should be moving along the direction of a vector. That is not the case here. Instead, something(the rigid body) is rotating around the direction of the vector. In the world of pure rotation,a vector defines an axis of rotation, not a direction in which something moves.   This is what my book (authored by Halliday, Walker, Resnick) says. But they mentioned with a caution that      Angular displacements cannot be treated as vectors. ....to be represented as a vector, a quantity must also obey the rules of vector addition..... Angular displacements fail this test.   Why do they fail in this test? What is the reason?


What does the AE/AF lock button do that half-pressing the shutter doesn't?

The Sony A6000 has an AEL button, while Nikon SLRs have an AE/AF lock button. What do these do that half-pressing the shutter to lock focus and exposure, and then recomposing, doesn't? I'm used to the latter method, and never used a camera that has a dedicated button.  I read that you have to keep both the AE/AF lock button pressed and the shutter half-pressed while recomposing. Isn't this harder than just keeping the shutter button half-pressed?  I'm aware that you can customize the AE/AF lock button to lock only focus, or only exposure, or both. This leads to two follow-up questions:   Can't you customize the half-press shutter to lock only AE or only AF? If you don't care about this level of customization, does the AE / AF lock button do anything that half-pressing the shutter doesn't?


Should meta requests be closed as duplicates of announcements if the same thing is requested in an answer to the announcement?

Whenever a new feature is announced by the SE team, it's typical for people to report bugs and request features by posting answers to the announcement. However, it often happens that some people who also come across the same bug or have the same feature idea don't notice the prior answer (probably since it's buried in answers) post the same thing as a new question.  If that happens, should that question be closed as a duplicate of the announcement, since it was already requested as an answer there, or should it be left open?  Personally, I disagree with closing them as duplicates (since you can only really close something as a duplicate of a question, not an answer, and there's no way to cleanly provide a link to the specific answer where it was requested earlier), but I've noticed others doing so on other metas. I'd like to see if the community thinks any differently.


What are the areas of mathematics in which a computer scientist must focus on?

I am studying mathematics and I am very interested in computer science but I want to know in what areas of mathematics must I focus on.


Why do rays exhibit mutual independence?

When two rays intersect each other, they do not disturb each other. This is what the "Principle of mutual independence of rays" states Why is that so? When a ray of ultro violet light and one of visible light intersect each other, they contain particles of different energies and also they are of different wave lengths Would they not interact at all? If there could be any interaction we can think about,  what could that be?


How does `ls` know whether it's piped or printed

ls normally prints like this:  1     1249  1653  23    33    4581  6202  6447  789  836  903        config.gz    kpageflags    sysrq-trigger 10    1253  1658  24    34    4582  6206  648   79   837  91         consoles     loadavg       thread-self 1003  1255  1662  251   347   4583  6207  649   791  84   923        cpuinfo      locks         timer_list 1004  1257  1667  252   35    4689  6209  6799  8    840  925        crypto       meminfo       timer_stats 1005  1261  167   26    357   48    6232  6986  80   841  998        devices      misc          uptime 1006  1263  1670  266   36    49    6242  6992  802  846  acpi       diskstats    modules       version 1008  13    1677  27    37    5     6267  6993  803  848  asound     dma          mounts        vmallocinfo   But when you pipe it eg to cat with ls /proc | cat, it prints it as if it got -1 (works the same also with grep and other commands):  1 10 1003 1004 1005 1006 1008 1010 1012 106 107 1073 108 109 1152 117 118 1247 1249 1253   My question is, how does it know it's being piped instead of printed? Or, how it happens?


Proper use of Past Perfect Vs Past Simple

English is my second language. I've learned all tense rule. Problem is every day I'm facing a huge confusion between Past simple and Past Perfect. According to grammar rule, we can you use Past perfect when talking about some point in the past and want to reference an event. But sometimes I notice people use  Past Perfect sentence without any reference event. Can you please give me some example with explanation and clear my confusion for a life time.


Which Stack Exchange site is most appropriate for asking software licensing related questions?


Splitting contents of a parenthesis to two lines

I have read about braces spanning more than two lines , and in many other places but am not sure about the mistake i've made in the following code, \begin{align} p\left( {l,m,n} \right) &= \left( {\frac{{{A_1}}}{{{A_1} + {A_2} +  {A_3}}},\frac{{{A_2}}}{{{A_1} + {A_2} + {A_3}}}, \right. \nonumber \\  &\qquad \left. {} \frac{{{A_3}}}{{{A_1} + {A_2} + {A_3}}}} \right) \end{align}  It compiles and gives the desired result, but also returns the error  Missing } inserted. \end{align}  Please help me with this issue, Thanks in advance for your help.


I have moved files and render does not show the videos anymore how to fix this?

I was rendering my video and while doing so moved files in my computer. I deleted folders, renamed them, moved them etc. The render had blank parts in it and now when I tried to render again it is completely black and videos don't even show in the preview. It is quite impossible for me to restore all the deleted folders/renamed files on my laptop, is there any other way to recover my work? I read this is a usual behaviour for Blender when the footage doesn't exist in its original Folder anymore. Thanks so much! Ginta


I am having an issue with a rendering. I am trying to render a outside architecture scene with a sky texture (nishita) For some reasons, there are some black stains/pixel in some random areas of the render... I'm using blender 2.90.1 Here is the file :  Any thought ? :D  Thanks Valentin


I need some clarity on the hyper-v virtualization strategy coming from ESXi 4.x.  Purpose: A VM for Sql Server 2012 w/ SP1 A VM for Sql Server 2014 CPT1    Hardware: Poweredge T100 8GB RAM, 2 SSDs JBOD and a 2TB 7200 WD backup drive. This is lab hardware for learning.  Problem: I am confused as to what the "free" Hyper-V server is for.   My understanding is that it will be the Host OS and the Guest OS will be 2012 Standard. Is this correct?


Can I travel to Paris with Schengen visa after Paris attacks?

I have Schengen Visa which have been issued by Italy. I would like to know that if I can travel to Paris after Paris Attacks? It is appreciated if someone give me any information about this case. because I've heard that french government suspend schengen visas policy. I have bought flight tickets from Milan to Paris for next week and I do not know that if i can take that flight.


I have a student visa under renewal and the German Kreisverwaltungsreferat has given a Fiktionsbescheinigung (temporary residence permit). Is it allowed to travel to other European countries with the Fiktionsbescheinigung ? Due to corona pandemic the card is taking too long to arrive.


In the chapter electromagnetic waves I was introduced with the concept of displacement current inside a capacitor. Since the region inside the capacitor is a dielectric there is no charge carriers in it. Then, what constitutes displacement current if it flows over there?   I know that it is a type of electric current formed by changing electric field.Conduction current involves flowing electrons and there is no electrons capable of moving about in a dielectric. But, then what is actually happening when we say displacement current?


Extrusions causing problems in edit mode

When I extruded vertices in edit mode, for some reason one of the sides of my 3-D model (the textured-looking side to the right) is creating a lot of errors. First off, it automatically sets extrusions on the x-axis. Secondly, it doesn't allow me to extrude planes into 3-D shapes. Thirdly, I can't increase the height of vertices without it creating a new face. Finally, it renders those automatic textures to create a grainy black texture in render mode. I attached an image with the solid object (top) and the rendered object (bottom). Note: I did not set any textures or alter the lighting on the model. Also, the left gray side is working perfectly fine without errors.