I made Ubuntu 14.04 (64bit) in my VM and I gave it 350gb of my 1tb HDD space and I did it fixed (not dynamically allocated) and i did it as a VDI and in my settings I set it to read the space as a SSD. I gave it 2 processors with 2000mb which is low so I was going to set up about 20gb of swap and swappiness of 50.  I was going to follow this guide to set up swap:    This is what I got:  oggie7797@oggie7797-VirtualBox:~$ sudo swapon -s [sudo] password for oggie7797:  Filename                Type        Size    Used    Priority /dev/sda5                               partition   2044924 14344   -1 oggie7797@oggie7797-VirtualBox:~$ free              total       used       free     shared    buffers     cached Mem:       2000792    1741236     259556      25060      13084     349624 -/+ buffers/cache:    1378528     622264 Swap:      2044924      14344    2030580 oggie7797@oggie7797-VirtualBox:~$    As you can see, it shows that I have swap even though this is a fresh install and all I have done is install Chrome-dev browser. So, now that I have given as much information that I can think to give I hope that someone can help me figure out how to either delete and create a fresh swap of my desired size or just simply edit this mysteriously preexisting swap to a larger size. Thanks in advance! :)

I have, by default, 250MB of swap space in Ubuntu, and I want to expand it to a larger size. I need 800MB, which I think will be enough to open several applications without having to hit the current limit of swap. I hope someone can help me.


I think this topic must have been posted earlier also.   I want to transfer my emails from mac mail to outlook 2011. When I go to import option in outlook 2011 and select the mac mail to import the mail boxes, all I get imported is blank folders every time.  The results were the same even after reinstalling office 2011.  Can anyone share their views on this topic and I would be very greatful if anyone could provide me solution of this question on how to migrate the emails from Mac Mail to Outlook 2011.

I need to import Apple Mail archived files in Outlook 2013 on Windows, but every time I open the import wizard and reach the file selection step, I cannot select the archived file. It doesn't even show in the dialog box.  I don't know what the issue is. Is it the file size issue as the archive file is large (about 7 GB) or there is any other fault?


Whenever I boot my computer, I do not get any boot-menu to choose OS. It neither boots until I keep pressing ENTER (return). When it finally boots, it boots into UBUNTU and not windows. When earlier I used to get boot-menu, UBUNTU was the first option so presumably on pressing ENTER it is booting in UBUNTU.   Here is output from boot-repair.   The boot repair doesn't recognize Windows 10 installation in sda4:

I installed windows 8.1 on my new laptop (which came with freedos), I later tried to dual boot the pc with ubuntu 14.04 (with legacy mode). I didn't get an option to install alongside windows 8 so I went with "something else" option. I created the root and swap partitions and then installed ubuntu. Everything went fine while installation. But after rebooting it directly boots into ubuntu, it does not show the GRUB menu for choosing between ubuntu and windows.   After using 'fixmbr' in the windows installation disc, I can now boot into windows but cannot boot to ubuntu. I deleted the linux partition and tried to the above again but I ended with the same problem.  So I was thinking if there was a solution like a command or something which could make GRUB identify the windows partition and give an option to boot to it.  (if it may help, my windows is installed in legacy mode(as in BIOS mode).. if I disable legacy mode the laptop does not boot into any os and it asks for an EFI file to boot from. Also my liveusb boots only through UEFI mode. When I boot it in normal/BIOS mode it shows a blinking '_' )  Please help guys.. I need both the OSes for my projects. And I need them fast.  Thanx in advance..


The book starts with humanity narrowly escaping the death of the sun consuming the Earth. All the humans are only allowed to bring few possessions with them so a little girl brings a notebook and starts a diary about the adventure.  Then they get to a planet with glass-like wheat and build huts and stuff. A large rock formation turns out to be eggs for an alien species and they hatch. By the end of the book the aliens come back to lay their eggs and many drown and the villagers forget all their stories and legends so they read the little girl's diary.

I read a story back in the early 90s about a group of colonists who landed on a planet where the wheat (or wheat-like equivalent) is some kind of crystalline plant. The colonists face starvation until one of them figures out how to process the wheat.  I think it was by Asimov but so far I haven't found it by looking for his works.  I also cannot remember if it was a novel or a short story.


Consider the following Cauchy problem: $$ \frac{\partial y}{\partial t} = \frac{-t + \sqrt{t^2+4y}}{2} \\  y(2) = -1 $$ I propose two valid solutions: $$ y_1(t) = 1 - t \\ y_2(t) = \frac{-t^2}{4} $$ Why does this not contradict the Existence and Uniqueness Theorem related to this kind of questions?

Prove that the solutions $y_1$ and $y_2$ for the initial value problem   $y'=$${-x+\sqrt{(x^2+4y)}}\over 2$ , $y(2)=-1$  are:  $y_1=1-x$  $y_2={{-x^2}\over 4}$  And explain why the two solutions not contradiction with the theory of existence and uniqueness.  ( sorry I don't speak English well )  My answer:  For the initial condition :  $y_1=1-x$ Satisfy the initial condition  $y(2)=-1$  $y_1=1-2=-1$   And Satisfy the differential equation  ${y_1}^{\prime}=-1$  ${{-x+\sqrt{x^2+4y}}\over 2}={{-x+\sqrt{x^2+4(1-x)}}\over 2}$  $={{-x+\sqrt{(x-2)^2}}\over 2}$  $={{-x+x-2}\over 2}=-1$  L.h.s.=R.h.s.  $y^{\prime}={{-x+\sqrt{x^2+4y}}\over 2}$  Also $y_2$ Satisfy the initial condition  $y_2={{-x^2}\over4}={-4\over4}=-1$   And satisfy the differential equation.   $y_2^{\prime}={-x\over 2}$  ${{-x+\sqrt{x^2+4y}}\over 2}={{-x+\sqrt{x^2+4({-x^2\over 4})}}\over 2}={-x\over 2}$  And for second part of exercise:  ${\partial f\over \partial y}={1\over \sqrt{x^2+4y}}$  and this not defined when $x=2, \ y=-1$  So $f(x,y)$ no satisfy lipshtize condition in any rectangular has (2,-1), Lipshtize condition including uniqueness of solution, so no contradict with the existence and uniqueness.  True ?  If this also wrong I well be delet it , I answered by the same way of my teacher :(


Prove that if $a$  is odd, then $a^2\equiv 1\pmod 8$I got this question in my discrete mathematics class, can anyone help me?Thanks.

To prove that if $n$ is odd, then $8 \mid n^2−1$, observe that as $n$ is odd either $n = 4k+1$ for some integer $k$ or $n=4k+3$ for some integer $k$. In the first case $n^2 -1=8(2k^2+k)$ and in the second case $n^2-1 = 8(2k^2 + 3k + 1)$.  Given an odd integer $a$, establish that $a^2 +(a+2)^2 +(a+4)^2 + 1$ is divisible by $12$. Solve by consideration of six cases.


I have the following While loop that will ask user input and then ask for it again and again before printing 'hello'. What I'd like to do is to ask the user for raw_input once and then run the while loop without the user having to type anything at all and keep the while loop running untill the user types 'q'.  inp = raw_input()  while inp != 'q':     inp = raw_input()     print 'hello world'

How can I poll the keyboard from a console python app?  Specifically, I would like to do something akin to this in the midst of a lot of other I/O activities (socket selects, serial port access, etc.):     while 1:       # doing amazing pythonic embedded stuff       # ...        # periodically do a non-blocking check to see if       # we are being told to do something else       x = keyboard.read(1000, timeout = 0)        if len(x):           # ok, some key got pressed           # do something   What is the correct pythonic way to do this on Windows?  Also, portability to Linux wouldn't be bad, though it's not required.


I understand that Linux is an open source OS, in other words I have the ability to change whatever I want with the source code of the system. Where is the source code located? For example I would like to add a new event to the mouse which let the user logout when the mouse pointer is moved left then right. Can someone provide me with some lessons or anything that would  me to understand how changes to the Source code happens?

I liked the mouse gesture of Windows 7 to minimize all open windows except the active one. Can I have that kind of gestures to use in Unity.  or What are the mouse gestures available for Unity?


I want to experiment with the  (ARC) in Google Chrome in order to see if Android applications can run easily in Ubuntu Touch. In order to do this, I first need to install Google Chrome. Given that this is merely an experiment and that I am not concerned with having to reflash my device (Aquaris E4.5), how can this be done?  At a quick guess, could Chrome be installed on Ubuntu Touch in the following way?  wget https://dl.google.com/linux/direct/google-chrome-stable_current_amd64.deb sudo su -c 'DEBIAN_FRONTEND=noninteractive dpkg -i google-chrome-stable_current_amd64.deb' rm google-chrome-stable_current_amd64.deb   Following this, an XMir launcher would likely be needed to run Chrome. How could this be written?    EDIT: Please note that I'm talking about desktop Chrome running on Ubuntu Touch, not mobile Chrome.

There doesn't seem to be a chromium (or Google Chrome) port available in Ubuntu Touch (OTA10.1, bq M10). Does one exist, or are there any plans to have one (even without touch / small screen optimizations)?


I just installed Ubuntu 13.10 en noticed that I have two indicators for WIFI in my upper panel.  In my 'panel' (where the clock is) I can see the time, a little envelope, a battery, an icon to adjust the sound etc.  And a symbol that shows me that I'm connected to the internet. BUT, I have 2 of these icons side by side. A normal one and one with a lock on it.

I have the exact problem in 13.10 as this user .  Here are some screenshots:      Here are some screenshots from another user:     ifconfig and iwconfig outputs  $ ifconfig lo        Link encap:Local Loopback             inet addr:XXXXXX  Mask:XXXXXXX           inet6 addr: ::1/128 Scope:Host           UP LOOPBACK RUNNING  MTU:65536  Metric:1           RX packets:2243 errors:0 dropped:0 overruns:0 frame:0           TX packets:2243 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:0            RX bytes:209889 (209.8 KB)  TX bytes:209889 (209.8 KB)  wlan0     Link encap:Ethernet  HWaddr XXXXXXXXX             inet addr:XXXXXX  Bcast:XXXXXXXX  Mask:XXXXXXX           inet6 addr: XXXXXXX Scope:Link           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1           RX packets:5925 errors:0 dropped:0 overruns:0 frame:0           TX packets:3361 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:1000            RX bytes:2951818 (2.9 MB)  TX bytes:630579 (630.5 KB)  $ iwconfig lo        no wireless extensions.  wlan0     IEEE 802.11abgn  ESSID:"XXXXX"             Mode:Managed  Frequency:2.437 GHz  Access Point: XXXXXXXX           Bit Rate=72.2 Mb/s   Tx-Power=15 dBm              Retry  long limit:7   RTS thr:off   Fragment thr:off           Power Management:on           Link Quality=49/70  Signal level=-61 dBm             Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0           Tx excessive retries:153  Invalid misc:472   Missed beacon:0


I want to print some text beside another text that has been printed before in python for example  print("Hello") a="This is a test" print(a)   What I mean is to print like this "HelloThis is a test" not in next line I know I shoud use print("Hello",a) but I wanted to use seprated print commands!!!!

I'd like to do it in Python. What I'd like to do in this example in C: #include <stdio.h>  int main() {     int i;     for (i=0; i<10; i++) printf(".");     return 0; }  Output: ..........  In Python: >>> for i in range(10): print('.') . . . . . . . . . . >>> print('.', '.', '.', '.', '.', '.', '.', '.', '.', '.') . . . . . . . . . .  In Python print will add a \n or space, how can I avoid that? Now, it's just an example, don't tell me I can first build a string then print it. I'd like to know how to "append" strings to stdout.


I am unable to understand the following block of code which I came across this site itself. It creates a function to find out the largest prime factor of a given number. It is given below:  def prime_factors(n): """Returns all the prime factors of a positive integer""" factors = [] d = 2 while n > 1:     while n % d == 0:         factors.append(d)         n /= d     d = d + 1  return factors pfs = prime_factors(1000) largest_prime_factor = max(pfs) # The largest element in the prime    My doubt is that the function prime_factors(n) would return the factors of n and not the prime factors, since the while loop is only checking if d is a factor of n and not if it is also a prime as it should be.  Please point out if I'm wrong and also the reasoning behind your logic. Furthermore, if I'm correct, then kindly provide a suitable block of code and the logic behind it in simple terms. Try to keep the code as simple as possible.

What is the best approach to calculating the largest prime factor of a number?  I'm thinking the most efficient would be the following:   Find lowest prime number that divides cleanly Check if result of division is prime If not, find next lowest Go to 2.   I'm basing this assumption on it being easier to calculate the small prime factors. Is this about right? What other approaches should I look into?  Edit: I've now realised that my approach is futile if there are more than 2 prime factors in play, since step 2 fails when the result is a product of two other primes, therefore a recursive algorithm is needed.  Edit again: And now I've realised that this does still work, because the last found prime number has to be the highest one, therefore any further testing of the non-prime result from step 2 would result in a smaller prime.


I am using JUNIT 4. I tried to assert the exception using the below code , but it did not work.  @Rule public ExpectedException thrown = ExpectedException.none(); thrown.expect(ApplicationException.class);   However when I annotated using the below , it worked and test passed.  @Test(expected=ApplicationException.class)   Please let me know if I am missing something.  import org.junit.Rule; import org.junit.rules.ExpectedException;  public class Test {      @Rule     public ExpectedException exception = ExpectedException.none();      @org.junit.Test     public void throwsIllegalArgumentExceptionIfIconIsNull()     {           exception.expect(IllegalArgumentException.class);         toTest();     }      private void toTest()     {         throw new IllegalArgumentException();     } }

How can I use JUnit4 idiomatically to test that some code throws an exception?  While I can certainly do something like this:  @Test public void testFooThrowsIndexOutOfBoundsException() {   boolean thrown = false;    try {     foo.doStuff();   } catch (IndexOutOfBoundsException e) {     thrown = true;   }    assertTrue(thrown); }   I recall that there is an annotation or an Assert.xyz or something that is far less kludgy and far more in-the-spirit of JUnit for these sorts of situations.


When I start Ubuntu there is a list of users I can click and enter the password for to log in.  How do I get a list of these users?  I tried to get users from the /etc/passwd file by doing this:  cut -d: -f1 /etc/passwd | sort -u   But this list was huge, nothing like the small list that shows up in the initial login screen.  Is there some other command or file I should be checking?

We all know that we have system users and service users. I am looking for a way to separate them as system users and service user list.  Is there any way ?


I have already proven that $\left(1+\frac 1{n}\right)^n\leq \sum_{k=0}^{n}{\frac{1}{k!}}$ . Does that help me in any way? I am stumped...  Any suggestions/hints?

How to prove that the following definitions of $e^x$ are equivalent, with as simple tools as possible and without any knowledge of $e$ or logarithms ?  $$\sum_{n=0}^{\infty} \frac{x^n}{n!}=\lim_{n\to\infty}\left(1+\frac{x}{n}\right)^n$$  Also preferably, prove that this is $a^x$ for some real number $a>0$.


Is it true that $|\mathbb{R}|=2^\omega=\omega_1$?  Note that $\omega_1$ is the successor of $\omega$ and $2^\omega$ is |all functions from $\omega$ to 2|.

As we know, $2^{\aleph_0}$ is a cardinal number, so it is a limit ordinal number. However, it must not be $2^\omega$, since $2^\omega=\sup\{2^\alpha|\alpha<\omega\}=\omega=\aleph_0<2^{\aleph_0}$, and even not be $\sum_{i = n<\omega}^{0}\omega^i\cdot a_i$ where $\forall i \le n[a_i \in \omega]$. Since $\|\sum_{i = n<\omega}^{0}\omega^i\cdot a_i\| \le \aleph_0$ for all of them.  Besides, $\sup\{\sum_{i = n<\omega}^{0}\omega^i\cdot a_i|\forall i \le n(a_i \in \omega)\}=\omega^\omega$, and $\|\omega^\omega\|=2^{\aleph_0}$ since every element in there can be wrote as $\sum_{i = n<\omega}^{0}\omega^i\cdot a_i$ where $\forall i \le n[a_i \in \omega]$ and actually $\aleph_{0}^{\aleph_0}=2^{\aleph_0}$ many.   Therefore $\omega^\omega$ is the least ordinal number such that has cardinality $2^{\aleph_0}$, and all ordinal numbers below it has at most cardinality $\aleph_0$. Hence $\omega^\omega=2^{\aleph_0}=\aleph_1$?


My goal is to be able to write:  \newcommand{\сlient_name}{Имя}   and use \client_name all over in my document. Right now I'm getting following errors like this:  Underfull \hbox (badness 10000) in paragraph at lines 670--670 [][]|\l_fontspec_font –ü—Ä–æ-–≥—Ä–∞–º-–º–∏-—Ä–æ-–≤–∞-   Full errors screenshot here -   I tried  and tried using  \newcommand{\сlient_name}{\foreignlanguage{russian}{Имя}}   but it didn't help.  How can I accomplish using cyrillic values in /newcommand variables?

I would like put picture into table, and my idea is define new command as below>   \newcommand{\EJ471}{\includegraphics[scale=0.150]{EJ_471.jpg}}   But compiler reports an error. If I use the command name for example \EJa, everything is all right. I've read similar questions as      But still I don't understand why it does not work.


I try to initialize an array in bash-4.2 next way:  ring=() ls -las | tail -n +4 | while read line > do > ring+=("$line") > echo ${ring[-1]} > done 3924 -rw-r--r-- 1 username group 4015716 Mar 23 15:14 script.jar 4 -rw-r--r-- 1 username group 9 Feb 29 12:40 rec.lst 5541 -rw-r--r-- 1 username group 5674226917 Mar 28 15:25 debug.out 8 -rw-r--r-- 1 username group 6135 Mar 25 12:16 script.class 8 -rw-r--r-- 1 username group 6377 Mar 25 11:57 script.java 8 -rwxr-xr-x 1 username group 4930 Mar 8 15:21 script-0.0.0.sh 8 -rwxr-xr-x 1 username group 6361 Mar 28 15:27 script-0.0.1.sh echo ${ring[0]}  echo "${ring[0]}"  echo "${ring[@]}"   What is wrong, why i get empty array after the finish of the loop?

Why do I get different values for $x from the snippets below?  #!/bin/bash  x=1 echo fred > junk ; while read var ; do x=55 ; done < junk echo x=$x  #    x=55 .. I'd expect this result  x=1 cat junk | while read var ; do x=55 ; done echo x=$x  #    x=1 .. but why?  x=1 echo fred | while read var ; do x=55 ; done echo x=$x  #    x=1  .. but why?


Let $R$ be a local ring with maximal ideal $I$ and residue field $k=R/I$ and $M$ finitely generated $R$-module.   My question is why $$M \otimes_R k\cong M/IM,$$ where $M \otimes_R k$ and $M/IM$ are $R/I$-modules.

Possible Duplicate:          In  the following claim was mentioned:  $R/I \otimes_R M \cong M / IM$  So I tried to prove it. Can you help me finish my proof? Thanks!    We recall that $M \otimes_R -$ is a covariant right-exact functor that it is exact if $M$ is flat and we observe that the following is an exact sequence: $$ 0 \to IM \xrightarrow{i} M \xrightarrow{\pi} M / IM \to 0$$  $R/I$ is an $R$ module since $R/I$ is a subring of $R$ closed with respect to multiplication from $R$ but it is not necessarily flat hence we only get exactness on one side:  $$  (R/I) \otimes_R IM \xrightarrow{id \otimes i} (R/I) \otimes_R M \xrightarrow{id \otimes \pi} (R/I) \otimes_R M / IM \to 0$$  Then $$ \mathrm{Im(id \otimes \pi)} = (R/I) \otimes_R M / IM  \cong (R/I) \otimes_R M / \mathrm{Ker} (id \otimes i) $$  so we want to show two things:   (i) that $\mathrm{Ker} (id \otimes i) = \{0\}$. To this end let $r + I \otimes im \in (R/I) \otimes_R  IM $ and assume $ id \otimes i(r + I \otimes im ) = r + I \otimes im = 0 + I \otimes 0$. I'm not sure how to proceed from here.   (ii) and that $M /IM \cong (R/I) \otimes_R M / IM $  Can you help me? Thanks.


The reason we cannot go is [because/that] our car needs new tires.   Which word to choose?

In a statement like     The weeds have grown overnight. The reason is because it rained yesterday   Is "the reason is because" good grammar? Isn't it better to say     The weeds have grown overnight because it rained yesterday   The second form seems simpler and the words the reason is seem to add nothing to the sentence. Is there any technical reason to avoid the longer form?


I am trying to find details of an Uzbekistan Airways flight from Tashkent to London on September 11th 2001. I believe it took off in the morning and landed in the afternoon but I need to know the flight number, departure and arrival times, type of plane, terminal it landed and whether it was delayed. Do you know where I can find this information? Thanks, Toby

The question  only deals with flights in the US sourced from the  . Is there some similar source for EU, Asia etc?


I have just come across Liskov Substitution Principle and casting during a lecture of (Java) Object-Oriented Programming. I understand what the principle states, that is, I can initialise a subclass with the type of a superclass:  SuperClass superClass = new SubClass();   My first concern regards the purpose of such operation. Why can't I just declare the subclass as usual (example follows)?  SubClass subClass = new SubClass();   Right after this, I got stuck on casting, as follows:  SuperClass superClass = new SubClass(); SubClass subClass = (SubClass)superClass;   Again, I struggle understanding the point of all of this.   Can anyone provide any clarification on the purpose of these procedures?

I have seen this mentioned a few times and I am not clear on what it means. When and why would you do this?   I know what interfaces do, but the fact I am not clear on this makes me think I am missing out on using them correctly.   Is it just so if you were to do:  IInterface classRef = new ObjectWhatever()   You could use any class that implements IInterface? When would you need to do that? The only thing I can think of is if you have a method and you are unsure of what object will be passed except for it implementing IInterface. I cannot think how often you would need to do that.   Also, how could you write a method that takes in an object that implements an interface? Is that possible?


This question is from Rotman's book An Introduction to the Theory of Groups.  How many $\alpha \in S_{n}$ are there with $\alpha^{2}=1.$ (Hint. (ij)=(ji) and (ij)(kl)=(kl)(ij))  My try: 1) There is identity permutation.  2) Transpositions: $\dfrac{n(n-1)}{2}$. ($2$ comes from the repetition in the transposition $(ij)$)  3) Product of two disjoint transpositions: $\dfrac{n(n-1)(n-2)(n-3)}{8}$ ($8$ comes from $2$ repetitions from the first transposition $2$ from the second and $2$ from the permutation of the two transpositions)  Even if my caslculations are correct I don't know how to get a closed formula for the summation.  I want to find the closed formula for the sumation and not counting the number of products of disjoint transpositions such that $\alpha^{2}=1$.  I am not a student, I'm just an old guy who likes to study Mathematics. I think I can live without knowing how to find the closed formula. Thanks for your hints.

This is not for homework, but I am not great at counting arguments and would like some feedback.  The question asks     Let $n \in \mathbb{N}$. How many $\alpha \in S_n$ are there such that $\alpha^2 = 1$?   I know that, if $\alpha^2 = 1$, then either $\alpha = 1$ or $\alpha$ is the product of disjoint transpositions.  If $\alpha = (i, j)$ is a single transposition, then there are $\frac{1}{2^1 \cdot 1!} \binom{n}{2}$ such $\alpha$ (the $2^1$ and $1!$ are put in the denominator to help in noticing the pattern later).  If $\alpha = (i, j)(k, l)$ is the product of $2$ disjoint transpositions, then there are $\frac{1}{2^2 \cdot 2!} \binom{n}{2} \binom{n-2}{2}$ such $\alpha$, where the $2^2$ appears in the denominator to account for the cyclic permutations of each transposition, and the $2!$ appears to account for the permutation of the transpositions themselves.  If $\alpha$ is the product of $3$ disjoint transpositions, then there are $\frac{1}{2^3 \cdot 3!} \binom{n}{2} \binom{n-2}{2} \binom{n-4}{2}$ such $\alpha$.  Extrapolating from this, I find that the total number of $\alpha \in S_n$ such that $\alpha^2 = 1$ is $$ 1 + \sum_{i=1}^{\lfloor \frac{n}{2} \rfloor} \frac{1}{2^i \cdot i!} \prod_{k=0}^{i-1} \binom{n-2k}{2}. $$  Does this look OK?  It looks like a rather ugly answer to me, so I have my doubts.  Any input would be welcomed.


I tried to give myself a player head using this command: /give @p skull 1 3 {SkullOwner:{Id:"ce27d2ce-ad02-4dfa-b3ee-bca732b2fd82",Properties:{textures:[{Value:"eyJ0ZXh0dXJlcyI6eyJTS0lOIjp7InVybCI6Imh0dHA6Ly90ZXh0dXJlcy5taW5lY3JhZnQubmV0L3RleHR1cmUvNDQ0Y2Q1ZDJmZDJmZTM5N2RkYjkyN2UxODRmMTllY2JkMGZlMjRhZjZlZjY4ODUyYzE3MmFlNDQ3Y2Q0In19fQ=="}]}}}  But it didn't work, giving me this error: Data tag parsing failed: Missing termination quote at: ...Q1ZDJmZDJmZTM5N2RkYjkyN2UxODRmMTllY<--[HERE]  This was the third time that this happened, when I tried to give myself a head (every time another) and the same error came up. How can I fix this?

I am running a server on version 1.16.1 and I'm trying to run the following command which I copied and pasted from a command generator: /tellraw @a ["",{"text":"Co-op >","color":"aqua"},{"text":" [PIG","color":"light_purple"},{"text":"+++","color":"aqua"},{"text":"]","color":"light_purple"},{"text":" Technoblade","color":"light_purple"},{"text":": I have come down from the land of potato gods."}]  Every time I run it it says:  Invalid chat component: Unterminated string at line 1 column 245 path $[6].text  I don't know what any of this means.


Please help I want to get the root folder of running jar.  D:\My Folder\My Folder1\ myjarfile  D:\My Folder\My Folder1\My Folder2   I want to save image in MyFolder2 using myjarfile. I have difficulties in coding in getting path of the executable jar:   String savePath = what goes there?(i want this "D:\My Folder\My Folder1\My Folder2")   ImageIO.write(image1, "png",new File(savePath));

My code runs inside a JAR file, say foo.jar, and I need to know, in the code, in which folder the running foo.jar is.  So, if foo.jar is in C:\FOO\, I want to get that path no matter what my current working directory is.


What differences -if any- are there between the complex numbers $\mathbb{C}$ and $\mathbb{R}^2$?  I am taking multi variable analysis now and I was wondering what possible changes there might be from the Analysis of two dimensions vs Complex Analysis.  A short summary of the differences would suffice.

I haven't taken any complex analysis course yet, but now I have this question that relates to it.  Let's have a look at a very simple example. Suppose $x,y$ and $z$ are the Cartesian coordinates and we have a function $z=f(x,y)=\cos(x)+\sin(y)$. However, now I change the $\mathbb{R}^2$ plane $x,y$ to complex plane and make a new function, $z=\cos(t)+i\sin(t)$.  So, can anyone tell me some famous and fundamental differences between complex plane and $\mathbb{R}^2$ by this example, like some features $\mathbb{R}^2 $ has but complex plane doesn't or the other way around. (Actually I am trying to understand why electrical engineers always want to put signal into the complex numbers rather than $\mathbb{R}^2$, if a signal is affected by 2 components)   Thanks for help me out!


I finally found the solution to a problem that was killing me. Before I found it, I asked an SO question about it, and had even started a bounty on the question. Can I now post a self-answer and, if no better answers get posted before the bounty expires, award myself the bounty?

Consider this question on .  I put out a 200 bounty on the question, but did not get an answer from anyone other than myself that worked.    In fact, my answer is also the highest up-voted on it at this point.  I know that allowing OP's to retract a bounty can be a slippery slope; in fact I think that once the bounty is put up it should stay up.  But why not allow the OP to answer their own questions with a bounty and reward it to them if they receive the same up-votes as others?  Yes, I am fully aware that bounties are a risk.  People will use them for numerous reasons such as trying to draw extra attention to their issues.  However, in my specific question, the only valid answer is the one that I gave.  Had it been anyone else's question, I would have received the bounty, but since it was my own I did not.


Good day to everyone. So, basically, it's no big deal that factorial grows faster than $2^n$, that's quite obvious, but I need to prove it, and that's where the problem begins.   I've tried some standard ways — no result. Stirling's approximation — no result. I tend to think that I either don't know something minor yet helpful or do something wrong. Help me, please:з

Why is     $$\lim_{n \to \infty} \frac{2^n}{n!}=0\text{ ?}$$   Can we generalize it to any exponent $x \in \Bbb R$? This is to say, is     $$\lim_{n \to \infty} \frac{x^n}{n!}=0\text{ ?}$$     This is being repurposed in an effort to cut down on duplicates, see here: Coping with  duplicate questions.  and here: .


How could I find an arbitray large prime number equal to 3k+2?

I need to prove that there are infinitely many primes with remainder of 2 when divided by 3. I started out similarly to Euclid's classic proof of an infinite number of prime numbers:  Suppose there is only a finite set of prime numbers with remainder of 2 when divided by 3, then we can write their product as:  $$ P = q_1 \cdot q_2 \cdots q_r, \qquad \text {for some integer } r, = $$ $$ (3q_1+2)\cdot(3q_2+2)\cdots(3q_r+2), $$ for integers $q_r$.   This is where I am stuck. I do not know how to get to a similar contradiction as Euclid did when he considered $P$+$1$ and how the $q_i$'s could not divide $P$+$1$ since they divided $P$. (If they divided $P$+$1$ then they would divide $P$ and $1$, where dividing $1$ is the contradiction). Any ideas on how I can get to a similar contradiction?  Origin —  Elementary Number Theory — Jones — p28 — Exercise 2.6


I'm a C/Python guy, shifted to 'Javascript' recently.  Basically, I receive an object (named context) in a function as an argument.The caller function's definition is hidden to me. Now I need to add a field(type) to the context. When I add type to context directly, it doesn't reflect changes in 'context'. But when I try to modify the value of one of the existing field of 'context', this change is reflected.  Then I create one more object(new_obj) and copy 'context' in the 'new_object', then tried to add the field in the 'new_object', but unsuccessful. So from this behaviour, I guess the value is not copied but the reference is.   So finally I need to copy field by field in the new_obj and then add the new field 'type'. Also if I create a local object, then new fields are being added and object structure is modified.  So far so good. But I was wondering about the implementation of the 'context' object in background caller function. I mean if there is some 'const' type thing here(as in C, (Random thoughts :P)), then at what level it is applied i.e. there is only restriction of adding new fields or also of changing values of the existing fields. Needed some light over this issue.

The primitive types (number, string, etc.) are passed by value, but objects are unknown, because they can be both passed-by-value (in case we consider that a variable holding an object is in fact a reference to the object) and passed-by-reference (when we consider that the variable to the object holds the object itself).  Although it doesn't really matter at the end, I want to know what is the correct way to present the arguments passing conventions. Is there an excerpt from JavaScript specification, which defines what should be the semantics regarding this?


This is a trivial question. We know that in the table 72: Variable-sized Math Operators to the pag. 40, we have the symbol for the line integral of a closed path named \oint for the circuiting. \documentclass[a4paper,12pt]{article} \usepackage{amsmath,amssymb} \begin{document} Table 72: Variable-sized Math Operators pag. 40. \[\oint\] \end{document}  But the high school students are not familiar with this symbol and I have thought of to use the symbol of the sum with the circle inside. But this symbol is only declared in stix fonts (see to pag. 46 \modtwosum).  If I should use mtpro2[lite] (that use the font Times New Roman) or the classic amssymb I should overlapping the two symbols of summation and the small circle in the center or can I find a more effective or best strategy? Any kind of suggestions are appreciated.

I'm busy answering a question by constructing a new math operator that uses the sum symbol and some TikZ placed on top. My answer as it stands can be found . It looks (I think) pretty good in display style, but too large when shown inline. Even if it automatically set the sum symbol into inline size, the placement of the TikZ would be off.  Is there a way to define different code for when the operator is used in display mathematics environments, and when it's inline? Alternatively, is there a way to detect when you are in display or inline mode?  From the aforementioned example, here is the code I constructed:  \documentclass{minimal} \usepackage{amsmath} \usepackage{tikz}  % Modify the coordinate (-0.3ex,0) to adjust alignment, and (0.1) to adjust the size. \DeclareMathOperator*{\osum}{\ensuremath{     \begin{tikzpicture}[baseline=(char.base), inner sep=0, outer sep=0]         \draw (-0.3ex,0) circle (0.1);          \node (char) at (0,0) {$\displaystyle\sum$};  % Want to define a second symbol for inline...     \end{tikzpicture}}% }  \begin{document}  \[ G=\osum_a^b H \]  And now in inline mode the equation $G=\osum_a^b H$ is obviously too big.  \end{document}


I have a 2008 server that I can access via remote desktop as I am the domain admin at my work environment. We are installing some software that will require a handful of users to login and use the software. I've always been confused to what type of licenses I need and the steps to install Remote Desktop Services. Do I just need to buy 5 CALs and install them once I install the required features? It looks like I'll need to install the Remote Desktop Session Host and Remote Desktop Licensing Service? Do I need any license for this part of the install, or does the 5 CALs cover me if I only need 5 concurrent users max?

This is a  about Licensing.    Questions on licensing are off-topic on Server Fault.  If your question has been closed as a duplicate of this question, then this is because we want to help you understand why licence questions are off topic rather than just telling you "it just is". In all likelihood, this question will not address your question directly, it was not meant to.    I have a question regarding software licensing. Can the Server Fault community please help with the following:   How many licenses do I need? Is this licensing configuration valid? What CALs do I need to be properly licensed? Can I run this product in a virtual environment? Can I downgrade this product to an earlier version? Am I entitled to feature X with license Y?


If $p_n$ is the nth prime, then prove that:$$\frac1p_1+\frac1p_2+....+\frac1p_n$$ is not an integer.  Since $p_1 ,p_2,..., p_n$ are all prime their reciprocal is not an integer so the sum should not be an integer. But I am not sure.

How can you prove that $\sum\limits_k \frac1{p_k}$, where $p_k$ is the $k$-th prime, does not result in an integer?


are identical posts. I tried to flag the second as a duplicate of the first, but couldn't because it claimed: "Your search returned no matches; please try a different search":

Most of the time, you don't want to see unanswered questions in the duplicate dialog, since you can't normally close as a duplicate of them. This behavior is intended, at least as it says :     The search results include only answered questions (per the usual SO definition of "answered", where the question must have an accepted or up-voted answer).   But there are times when you can close against something unanswered:   On meta Questions with the same author   But the dialog doesn't show unanswered posts in those circumstances.  In the past, I have wondered why I was mysteriously unable to find some specific posts in the duplicate dialog. For example:   I saw two near-identical posts by the same user. I was unable to find the duplicate in the dialog, even after typing in the exact title or using the user:1 search trick. On meta,  does not show up in the dialog. I posted about this before, on , but at that point I only knew it affected that one post (the joke's on whomever got rid of "too localized" I guess).   In both cases, I had to go get the URL and paste it in manually.    The best way to see this is to use answers:0. I hope you don't think there are only two unanswered questions here!        Most of the time, the results for this search are merged questions (but not all the merged questions). I have no clue why that one post shows up here. (Maybe it was merged and un-merged at some point?) This current behavior is pretty useless.    It should be very easy to fix the dialog on meta. It might take a little more effort to have the same user's posts show up on main, but I can't imagine it being prohibitively difficult.


To find the size of a structure in C   struct student     {      char name;      int age;      float weight;     };  main () {     int i,j,k,l;     struct student s1;     i=sizeof(s1.name);     j=sizeof(s1.age);     k=sizeof(s1.weight);     l=sizeof(s1);     printf ("\n size of name    %d",i);     printf ("\n size of age     %d",j);     printf ("\n size of weight  %d",k);     printf ("\n size of s1      %d",l);  printf("\n"); }   My output is:  size of name    1  size of age     4  size of weight  4  size of s1      12   But structure size should be the sum of sizes of its members. Why am i getting 12 instead of 9 as size of structure variable s1. Can someone explain what is wrong.

Why does the sizeof operator return a size larger for a structure than the total sizes of the structure's members?


I would like to know how much power I need for magnetic levitation.  $$P = Fv.$$  $F = F_g \approx \text{mass} \times 10$, okay. But $v = 0$! I can't believe I need no power to keep an object in the air. How does one explain this?

If an airplane of mass $m$ is flying at a constant speed $v$, the power of the airplane is  $$P = m\cdot v\cdot g $$ where $g$ is the acceleration of gravity and therefore:  $$ F = m\cdot g, $$ but, if the velocity is constant, there is no net force as well as no work done. Then how can the magnitude of power be non-zero?


how can I place a large equation at the bottom of a page when using the document class scrartcl with the twocolumn option enabled.  I know about , but I'd rather stick with twocolumn mode and not use the multicols package because of problems with figure placements.  Any help is much appreciated.  Edit: to clarify, I do not want to have the equation printed where it's defined, but rather on the bottom of the same page.

I use scrbook class (see bellow) in my book and sometimes I need typeset wide equation.  \documentclass[%     ,fontsize=12pt    %      ,a3paper         % pagesize     ,twocolumn  ]{scrbook} \areaset[5mm]{250mm}{350mm} \unsettoc{toc}{twocolumn}   Is it possible to partially switch between one and two column formatting?  I tried to use the library widetext, but I'm afraid that it is not a part of the MiKTeX distribution. I would like to typeset wide equation in the text, not only at a bottom or top side. Is it possible?  MNWE: (added wide equation; for \setchaptertoc see )  \documentclass[twocolumn]{scrbook} \usepackage[nohints]{minitoc} \usepackage{amsmath, amsthm, amssymb, amsfonts, amsbsy} \usepackage{bigints} \usepackage{mathtools} \mtcsetrules{minitoc}{off} \usepackage{lipsum}  \newcommand*{\setchaptertoc}{%   \setchapterpreamble{   \vspace{1.85\baselineskip} % workaround for removed rule   \smash{\makebox[\linewidth]{\hrulefill}} % workaround for removed rule   \vspace{-1.85\baselineskip} % workaround for removed rule   \minitoc   \vspace{-1.15\baselineskip} % workaround for removed rule   \smash{\makebox[\linewidth]{\hrulefill}} % workaround for removed rule   \vspace{1.15\baselineskip} % workaround for removed rule }} \newcommand{\dd}[1]{\hspace{2pt}d#1}  \begin{document} \dominitoc \tableofcontents  \setchaptertoc \chapter{One} \lipsum[1]     \begin{equation}\label{fyz:fey_eq_elstat18}       E_x(x_1, y_1, z_1) =          \int\limits_{\substack{\text{all}\\\text{area}}}\varrho(x_2, y_2, z_2)         \frac{x_1-x_2}{[(x_1-x_2)^2+(y_1-y_2)^2+(z_1-z_2)^2]^{\frac{3}{2}}}\dd{x_2}\dd{y_2}\dd{z_2}     \end{equation}  \lipsum[1]     \section{One, one} \lipsum[2] \subsection{One, one, one} \lipsum[3] \section{One, two} \lipsum[4]  \setchaptertoc \chapter{Two} \lipsum[5] \section{Two, one} \lipsum[6] \section{Two, two} \subsection{two, two, one} \lipsum[7]  \setchaptertoc \chapter{Three} \section{Three, one} \lipsum[8] \section{Three, two} \lipsum[9] \end{document}


So i wanna print this code.. it says:     non - static method rain cannot be accessed from a static context.   the question is to print the names of all the months and their rainfall in parallel columns and their total average and the month with highest and lowest rainfall. Please help me out.   public class rainfall  {      String[] rain =  { "Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec" };     double[] values = { 0.40,0.94,3.21,3.74,1.73,1.03,1.27,2.58,6.98,6.90,2.80,2.53};       public double Total( double total )     {         total = 0;          for( int i = 0 ; i < values.length ; i ++ )         {             total += values[i];         }          return total;     }      public double Average( double average)     {         double total = 0;         Total (total);         for ( int j = 0; j < values.length; j ++ )         {             average = total/values.length ;         }          return average;     }      public String mostRain (double high,String highest )     {         high = values[0];          for(int i = 1 ; i < rain.length ; i ++ )         {             if ( values[i]>high )             {                 highest = rain[i];             }             return highest;          }     }      public String leastRain ( String least, double low )     {         least = "";         low= values[0];          for(int i = 1; i < rain.length ; i++ )         {             if ( values[i]<low )             {                 least = rain[i];             }              return least;         }     }      public static void main(String[]Args)     {         String highest = "" ;         String least = "";         double total = 0 ;         double average = 0 ;         double high = 0;         double low = 0;            System.out.println(" AUSTIN Tx RAINFALL 2009 " );          for( int i = 0 ;  i < rain.length ; i ++ )         {             System.out.println(rain[i]+"\t"+values[i]);         }          System.out.println(Total(total));         System.out.println(Average(average));         System.out.println(mostRain(highest,high));         System.out.println(leastRain(least,low));      } }

The very common beginner mistake is when you try to use a class property "statically" without making an instance of that class. It leaves you with the mentioned error message:     You can either make the non static method static or make an instance of that class to use its properties.   Why? I am not asking for solutions. I would be grateful to know what is the reason behind it. The very core reason!  private java.util.List<String> someMethod(){     /* Some Code */     return someList;             }  public static void main(String[] strArgs){                // The following statement causes the error. You know why..     java.util.List<String> someList = someMethod();          }


Why isn't the operation $\log_{-2}( -8)$ defined if $(-2)^3 =-8$?

Can we take the negative numbers as base in taking log?    For example:$$\log_{(-2)}4=2$$ $$\log_{(-3)}81=4$$ etc.


I'm trying to install the Ubuntu 18.04 to my laptop HP Laptop 15-da0xxx it is possible to my laptop. Thank you

I have a device on which I would like to install Ubuntu. How do I find out if Ubuntu will work on it?


The Problem  I'm trying to create a diagram that is similar to this diagram generated by the matlab command waterfall():  The data for it is stored in a csv file. In this case it's 129 columns of data, the first one is just an index, the others contain the data for the 128 lines. The data used in the above image can be found     What I've Tried  \documentclass[crop, tikz]{standalone} \usepackage{pgfplots} \pgfplotstableread[col sep = comma]{data.csv}\mydata \begin{document} \begin{tikzpicture}   \begin{axis}[     no markers,     xmin = 0, xmax = 140,     ymin = 0, ymax = 150,     zmin = 0, zmax = 0.07,     x dir = reverse]     \addplot table[x = 1, y index = {0}, z index = {1}]{\mydata};     \addplot table[x = 2, y index = {0}, z index = {2}]{\mydata};   \end{axis} \end{tikzpicture} \end{document}   Basically, I'm trying to give each line a fixed x value and have it read the y and z values from the csv. For now I'm trying to add a few lines manually. Later I'd like to generate the addplot entries using some kind of for loop that.

I am trying to reproduce a similar figure to the following one. My first guess was to use pgfplots but I didn't find any example that I could use as a starting point. At the moment I am unsure if pgfplots is actually the right package or I should rely on something else e.g. TikZ.   Since I don't really know where to start, I would appreciate any piece of code that points me in the right direction.    EDIT  Here is some dummy data for the plots.  plot1   plot2   plot3   plot4 0       0       0       0 3.466   2.058   0       0 4.262   2.976   0.001   0 3.822   3.168   0.006   0.008 2.953   2.936   0.019   0.063 2.065   2.492   0.046   0.265 1.332   1.977   0.092   0.734 0.797   1.478   0.164   1.508 0.443   1.045   0.268   2.44 0.228   0.698   0.412   3.219 0.107   0.438   0.598   3.524 0.046   0.256   0.831   3.219 0.017   0.138   1.109   2.44 0.006   0.067   1.429   1.508 0.002   0.029   1.78    0.734 0       0.01    2.141   0.265 0       0.003   2.479   0.063 0       0.001   2.736   0.008 0       0       2.808   0 0       0       2.465   0 0       0       0       0


I'm trying to move my hobby computer from Windows server to Ubuntu. Unfortunately I get stuck when trying to convert my windows disks that is in raid0 to create one big volume to ubuntu. I want the same setup in Ubuntu and tried to follow  () by using mergerfs fuse to do this. Everything is working down to "Create fstab entries" but afterwords I get an error about something called LDM (Logical Disk Manager) and something about NTFS. Is there any other guide that can explain how to convert the drives from windows?

I am a new Ubuntu user with a fresh installation, and am eager to get started with it. However, all of my important data is on Windows software RAID 0 array, and I need it to stay there as I'm also dual booting Windows. I need access to this data on Ubuntu, and can't really get anything real done until I have access.  I have already researched this subject as best as I could, and I managed to find a very helpful post:      The post describes how to get Ubuntu to see a Windows RAID 0 array that is made up of two drives. The main command used is sudo mdadm --build /dev/md0 --chunk=64 --level=0 --raid-devices=2 /dev/sdd2 /dev/sdc2. According to that user, and the other posters in the thread, it actually does work. That's great.  I have not tried following these instructions yet. Why? The post includes a warning about how you must not write to it if you enter the wrong chunk size; it's understandable how that could cause problems. My concern is that my setup is different to their example, and I am not sure that the commands should be entered exactly the same for my setup. I am afraid to break it by doing it wrong, and therefore wish to get the advice of somebody more experienced.  This is how my setup differs from their example:   I have three 1 TB drives, not two drives (of whatever size they used). I have two RAID 0 partitions spread across those three drives: one 500 GB and 2.3 TB. This means that I need to NOT use the full disks when creating the RAID array, but instead use just part of them. I used a non-default block size for at least one of my RAID 0 partitions when I set them up years ago. I have no idea if this block size is the same as the chunk size that they mention. My 500 GB partition has a block size of 4 kb (4096 bytes per cluster), and my 2.3 TB partition has a block size of 64 kb (65536 bytes per cluster).   The relevant output from sudo lsblk -o NAME,FSTYPE,SIZE,MOUNTPOINT,LABEL (for just those three RAID0 drives) is:  NAME   FSTYPE   SIZE MOUNTPOINT            LABEL sdb           931.5G             ├─sdb1            1M             ├─sdb2          127M             └─sdb3        931.4G             sdc           931.5G             ├─sdc1            1M             ├─sdc2          127M             └─sdc3        931.4G             sdd           931.5G             ├─sdd1        166.7G             └─sdd2        764.7G    The relevant output from cat /proc/partitions (for just those three RAID0 drives) is:  8       16  976762584 sdb 8       17       1024 sdb1 8       18     130048 sdb2 8       19  976631478 sdb3 8       32  976762584 sdc 8       33       1024 sdc1 8       34     130048 sdc2 8       35  976631478 sdc3 8       48  976762584 sdd 8       49  174763008 sdd1 8       50  801865728 sdd2   The "Disks" program in Ubuntu displays the following partitions for my drives:  /dev/sdb:   GUID Partition Table . /dev/sdb1:  1.0 MB, Microsoft LDM metadata. /dev/sdb2:  133 MB, Microsoft Reserved. /dev/sdb3:  1.0 TB, Microsoft LDM data. /dev/sdc:   GUID Partition Table partitioning. /dev/sdc1:  1.0 MB, Microsoft LDM metadata. /dev/sdc2:  133 MB, Microsoft Reserved. /dev/sdc3:  1.0 TB, Microsoft LDM data. /dev/sdd:   Master Boot Record partitioning. /dev/sdd1:  179 GB, Unknown. /dev/sdd2:  821 GB, Unknown. /dev/sdd:   136 MB, Unallocated space.   I hope I've provided enough information here. So now, my question is this: what is the proper command for me to enter with my setup, so that I can access both of my Windows RAID 0 partitions from Ubuntu?  Thank you very much in advance.


The concept of dependency injection is not clear to me. I read about it. What i learn is it is used to inject dependency instead of adding it. Can someone explain it to in simple way if possible with example?

There have been several questions already posted with specific questions about , such as when to use it and what frameworks are there for it. However,  What is dependency injection and when/why should or shouldn't it be used?


I'm a mac user and tried to install the new star wars battlefront, which is Windows only. I purchased the for PC 'download only' disc from EA, which includes only a  code for installation.   I downloaded origin, setup an account, and added the code that I got from EA. Then I just got a screen telling me 'Game only available on Windows' and thought, 'oh, balls'. So now I want to sell the game code on ebay.     The question is, will another user have a problem installing and playing this game using this code? Is there a way to remove it from my account to allow for it to be used on another user's origin account?

I bought Dragon Age Inquisition, I have all the disks, the problem is that my computer isn't powerful enough for it and so it lags a lot. I've done all I could, but the only way I can play normally is on the lowest resolution, which isn't fun.  I'll buy it on Xbox instead and I want to sell my current PC version, but I already redeemed the activation code. If I sell it can someone else use it on their PC ?


Does anyone know the title of a book where an individual or group ventures through an Earth that is continually swept by timewaves which transport to different era?

I read a book nearly twenty years ago when I was in Jr high.  What I remember is a man traveling around with a teenage girl, (nothing twisted) in a camper I think, and there were these weird blocks of fog or mist. I believe there may have been a dog also. It was a novel in English. I believe it was written in the 70's or 80's. I remember a part in the book where two blocks of the fog got stuck right where a woman's house was. The man and girls stopped there for the night. I remember the girl didn't talk much. That's about all I can remember. I don't even remember the story behind what caused the fog and I really want to reread the book.


I came across  question, and I must admit I've never seen such a long page with so many long answers.  The problem is easily navigating between the answers.  Sometimes I don't have time to read everything at once, and it becomes rather annoying to endlessly scroll to pick up on where I left off.  I think it would be helpful to have a box (in the white space on the left) with links to different answers to hop down to them. Of course this would only be activated when the page becomes a certain length and/or if there are X amount of answers.  Here is an idea (excuse my horrible design skills):

Maybe just small optional DVD-player like chapter-selection icons directly below the vote buttons, something à la  >>, <<, >|, |<   for next, previous, last and first answer.


Let $A$ and $B$ be two sets. Prove the existence of an injection from $A$ to $B$ or an injection from $B$ to $A$.  I don't know how to proceed, since I don't have any information on $A$ or $B$ to begin with.  Does anybody have a hint ?

For any pair of sets $A$ and $B$, we can define $A\le B$ iff there exists injection $f\colon A\rightarrow B$. I am trying prove that  $$(A\le B)\vee (B\le A).$$  I have tried assuming  $\neg (A\le B)$, then proving $B\le A$ by constructing the required injection, but I haven't been able to make any progress. Any hints, etc. would be appreciated.  EDIT  Assuming  $\neg (A\le B)$, can you prove there exists a surjection $f: A\rightarrow B$? Then it would be easy, by applying AC, to construct an injection $g: B\rightarrow A$


I'm working on a gaming product where users can perform a wide variety of actions from rating, writing a review, adding to lists, log the game in their 'backlog' etc..  Each of those can lead to multiple further screens with more user actions so i worry that using a FAB isn't relevant anymore.  Should a FAB be kept to single unique action (write a review, Log etc.. )? and if so what other alternatives could there be without cluttering too much?    Thanks in advance!

According to Material Design Guidelines, Google states that on any page the primary action of the page can be promoted in the floating action button.  But what if on different pages, we use similar floating action buttons for different proposes?   Both actions on both pages are adding, but the item that is added is different so the functionality is kind of different, but yet it's adding and I can't think of a different icon like "plus icon" to be placed on the fab. Keeping in mind that the pages may be blow by blow, is it a bad practice to do so?


I am trying to create a simple todo app that posts new items and appends to the DOM and removes the item when it is clicked on. I am able to get todo-items to append to the page but they are not being removed when they get clicked on. I beleive it has something to do with my onclick event handler as it is not selecting the "li" properly. Any thoughts?  heres the code:
             <textarea id = 'todoItem'></textarea>             <button id = 'submitButton'>Post</button>

Items

I have a bit of code where I am looping through all the select boxes on a page and binding a .hover event to them to do a bit of twiddling with their width on mouse on/off.  This happens on page ready and works just fine.  The problem I have is that any select boxes I add via Ajax or DOM after the initial loop won't have the event bound.  I have found this plugin (), but before I add another 5k to my pages with a plugin, I want to see if anyone knows a way to do this, either with jQuery directly or by another option.


Example:    How can I get the first cell value?

Can anyone recommend a simple API that will allow me to use read a CSV input file, do some simple transformations, and then write it.  A quick google has found  which looks promising.  I just wanted to check what others are using before I couple myself to this API.


The stackoverflow.com guidelines request specific questions that programmers would ask, no vague questions that would elicit discussion or debate. But as an architect a lot of my questions are just that. In a lot of cases I'm looking for other professionals opinions on a topic. An example is a question I was planning on asking today: "What are considered the best architectures for high volume data capture?" I have a need to design a system to capture a lot of small data elements and wanted to hear other opinions of the best way to do that.    Is there a Stack Exchange site to discuss those kinds of questions?

Stuff like polls, recommendations based on subjective constraints, puzzles, webcomics etc. do not belong on the serious main SE sites, where professionals should be considered at work and having just a few spare minutes ("code's compiling") to answer questions, so they should not be distracted by such things. However, I'd also like to have a home for these things still using the SE engine. For the reason I mentioned before, this needs to be a separate place though. Let's call it four.[sitename-here].com.


I want to pick a random number that is -1<x<1, but if I use Math.random, it is only -1<=x<1. How do I get a random number in this range? double x = (Math.random*2)-1

How do I generate a random int value in a specific range? I have tried the following, but those do not work: Attempt 1: randomNum = minimum + (int)(Math.random() * maximum);  Bug: randomNum can be bigger than maximum. Attempt 2: Random rn = new Random(); int n = maximum - minimum + 1; int i = rn.nextInt() % n; randomNum =  minimum + i;  Bug: randomNum can be smaller than minimum.


I know electrolytic capacitors must be derated according to the applied voltage, with some losing a significant part of their nominal value at high voltages.  Is it a similar case with film capacitors? I am using these . Will be applying 400Vdc on these.  I did try looking it up, I could not find a clear answer.

After looking around, I have found quite a few things about how DC bias reduces effective capacitance for a ceramic, or electrolytic capacitor, however nothing seems to talk about the effect on film capacitors. I've found a couple of papers about film caps (such as: ), and they mention frequency and temperature, but I can't find anything about DC bias reducing capacitance.  I have obviously checked the data sheet of the component I plan on using (), but there isn't anything about DC bias in that (unless I've just failed at spotting it).  This suggests to me that they aren't affected by DC bias, but that seems a bit of a bold claim, and I can't see that stated anywhere.  Are film capacitor values affected by DC bias? If so, can anyone point me to some data about what the roll off is?  I am planning to use some film capacitors in an application with 48-60V DC across the capacitors and a ripple current around 30 amps.


I am using this  Shamir implementation. I generated 4 shares from secret (threshold of 2).   I am wondering if I can recreate (interpolate) original polynomial from these shares (polynomial which was generated from random numbers)  and base on it create a new point (share). In normal cases (not GF(2) fields) is will be an easy task, because after I get pair of points $(x,y)$ I can easily interpolate linear function.

I would like to have a secret sharing scheme with the following properties:   Generate secret $S$ a split it to $N$ shares $(s_1, s_2, ..., s_N)$  Require $k$ of $N$ shares in order to reconstruct secret $S$ Update $N$ to $N+1$ and generate new share $s_{N+1}$ (everything remains the same, $N$ shares not changed)   The scenario is that I use Shamir secret scheme to split secret $S$ into for example 4 parts and require 2 of them to be present in order to reconstruct $S$. In that case if I would like to reconstruct S then I have to also input scheme type, i.e. 2 of 4.  What if I need to update number of parts but need to preserve existing shares and be able to reconstruct the same secret $S$? Is there a way how to do it?


Once my laptop goes to suspend, it doesn't wake up. I can see the LED lights saying that PC is on but screen remains black.  I am really new to Ubuntu and just recently installed it.   My laptop is Lenovo z50/70  Using Ubuntu 14.10 - haven't really done any customization on it.

I'm using Ubuntu 12.04 & everything about it is great except that it just won't resume after suspend. I've tried the suggestions listed in this thread  but none worked. I'm using Lenovo Y510P. I'm new to Ubuntu, or unix for that matter, so please let me know if there's anymore  information that I should be posting. Thanks.  update  I tried the suggestion by Dima on this post . The machine wakes up from hibernation but immediately the screen gives a screen like this     Wondering if this is an issue with the graphics card or something.


I have a Realtek RTL8821CE and when i try to use the apt download command, it can't find any of the necessary files. I'm sorry if this is unclear, I'm new here and I'm new to all of this.

I'm trying to install drivers for my Wifi on my HP All-in-one desktop. I've been told to show the output of the command "sudo lshw -C network" so here it is:  *-network description: Ethernet interface product: RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller vendor: Realtek Semiconductor Co., Ltd physical id: 0 bus info: pci@0000:01:00.0 logical name: enp1s0 version: 15 serial: 48:ba:4e:5c:06:5f size: 100Mbit/s capacity: 1Gbit/s width: 64 bits clock: 33MHz capabilities: pm msi pciexpress msix bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=full firmware=rtl8168h-2_0.0.2 02/26/15 ip=192.168.1.21 latency=0 link=yes multicast=yes port=MII speed=100Mbit/s resources: ire:31 import:e000(size=256) memory: fea04000-fea04fff memory:fea00000-fea03fff  *-network UNCLAIMED description: Network controller product: Realtek Semiconductor Co., Ltd. vendor: Realtek Semiconductor Co., Ltd. physical id: 0 bus info: pci@0000:02:00.0 version: 00 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress cap_list configuration: latency=0 resources: import:d000(size=256) memory:fe900000-fe90ffff   Output from "lspci -nnk | grep -A2 0280":  02:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd. RTL8821CE 802.11ac PCIe Wireless Network Adapter [10ec:c821] Subsystem: Hewlett-Packard Company RTL8821CE 802.11ac PCIe Wireless Network Adapter [103c:831a] 03:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. RTS5229 PCI Express Card Reader [10ec:5229] (rev 01)


I don't know what i've clickin, but somehow this happening. when i enter edit mode, the wireframe in the backside keeps showing on, and i can't choose the proper faces which i want, pls help me :D

I have recently started using blender and one of the models I'm working on has dark shadows along edges. I started this model from scratch. I can't remember them being there when I first started the model, but I had trouble joining areas together and think I've pressed something I shouldn't have. However, there are so many options I'm not sure what I did.  Here is an image of what I mean   The one on the left has the shadow. As a test I started a new model, which is on the right in the image, and as you can see it doesn't have any shadows.  Also, occluded vertices partially show through the model. Occlusion doesn't work properly.   In orthogonal view small darkened triangles appear along the the edges.    I don't really want to start the model again from scratch so any ideas on how to remove this shadow would be great. Thanks.


If I leave my computer alone for some 1-2 hours, I don't know exactly how long, it tries to logout. But I have terminal programs running (CLI tools fetching data from FTP, or doing processing of some kind, etc.), so the computer never fully logs out. I don't want it to logout though, I want it to stay logged in. It's also quitting the browser and my text editor, which I don't want it to do. What settings do I change? In System Preferences, I clicked "Start after: Never". I put Energy Saver to never sleep with or without battery. But I don't know what else to change to get it to not log out. Maybe this helps:

I have this strange problem of my Mac rebooting. Everything was normal until I started syncing photos from iCloud (this could be coincidental, maybe not). First time I noticed a problem after 1-2 days as my system fan started going crazy, with CPU utilization at a max, several minutes later followed by system shut down. I traced the 100% CPU to Spotlight reindexing constantly; I temporarily disabled indexing:  sudo mdutil -a -i off   Problems with fans went away, but now photos service was going at very high CPU, accelerating fans again. I disabled Photos app (as much as I knew how) to avoid performing any analysis. This solved the fans and CPU going crazy problem. I could live without Photos on this Mac, no problems here.  Photos/Spotlight searching might just be coincidental, this part I'm not sure. Just so my system was more or less stable for at least several month before this addition.  But, here's the problem:  As soon as I leave my computer alone, after several minutes of inactivity, something happens that my computer goes into sudden reboot. I can't even leave it for 5 min for bathroom break. For information: putting computer to sleep was always disabled on my Mac, only screen saver and later on monitors were to trigger. Now I disabled it all, with no difference. I tried: 'caffeinate' with no difference as well.  Also, working on my Mac, performing various tasks has no effect whatsoever, but leaving it idle, goes to reboot soon.  Please help. What I was trying to find is if there's some kind of log that I could dump of a system on freeze, some entry to trace of what was the final activity before my Mac reboots. Any idea?


I am a green card holder and live/work in the US. I want to travel to Iran in July 2021 for a couple of weeks. Am I still exempt from the 14 days quarantine rule in a third country (based on the new ) before entering the US?

My wife is a green card holder and she wants to travel to Iran in the next month for a couple of weeks. Is she exempt from current 14 days quarantine rule before entering the US?


I am new to relativity and particle physics and I am struggling to understand the conventions for the dimensions that are used in particle physics. I have read  and as I understand it: $$\sqrt{s}=\text{Total energy of collision bewteen two particles in the Centre of Mass frame}=E_{\mathrm{cm}}$$  Now suppose I need to calculate the energy requried to make a $Z$ particle of mass $91\mathrm{GeV/c{^2}}$ in the COM frame (by colliding positrons and electrons both with mass $0.511\mathrm{MeV/c{^2}}$; but this detail is not needed for this question). I'm pretty sure that I use the relation at the top of this post; $$E_{\mathrm{cm}}=\sqrt{s}=91\mathrm{GeV}\tag{1}$$  But there is one serious problem with equation $(1)$ I just wrote above: The mass of the $Z$ particle has units of $\mathrm{GeV/c{^2}}$. But I know that $E_{\mathrm{cm}}=\sqrt{s}$ must have units of energy ($\mathrm{GeV}$) so from where I'm sitting the only way to make this dimensionally correct is to write $$E_{\mathrm{cm}}=\sqrt{s}=91\frac{\mathrm{GeV}}{\mathrm{c^2}}\times \mathrm{c^2}$$ But I can't just multipy by $c^2$ just because I 'feel like it' (to give it units of energy). Unless there is something else going on that I am missing could someone please explain to a lost and confused person why multiplying by $c^2$ is justified here?   Is there perhaps some formula that eludes me here?  By the way, I read  but unfortunately it still doesn't answer my question here.

This is a quote from the book A first course in general relativity by Schutz:     What we shall now do is adopt a new unit for time, the meter. One meter of time is the time it takes light to travel one meter. The speed of light in these units is    $$\begin{align*}\end{align*}$$      $$\begin{align*}  c &= \frac{ \text{distance light travels in any given time interval}}{\text{the given time interval}}\\ &= \frac{ \text{1m}}{\text{the time it takes light to travel one meter}}\\ &= \frac{1m}{1m} = 1\\ \end{align*}$$      So if we consistently measure time in meters, then c is not merely 1, it is also dimensionless!   Either Schutz was on crack when he wrote this, or I'm a dope (highly likely) 'cos I can't get my head around this:  The space-time interval between different events at the same location measures time, and between different events at the same time measures space. So they're two completely different physial measurents: One is a time measurement using a clock, the other a space measurement using a ruler. In which case the units of $c$ should be $ms^{-1}$  Does Schutz correctly show how $c$ can be a dimensioness constant?


This is my first modeling try at a person, and I am still quite new to blender, but I was wondering if anyone knew why I get this gradient in my object? It seems to be along some of the edges. Even worse, they appear to show up on cycles render, not entirely sure what is going on, please help!

While rendering a mesh with smooth shading on, I get a dark region/shadow on certain faces. The effect is more evident when smooth shading is applied to a mesh containing ngons, with the ngons turning black when rendered.   The blackening effect is visible in the viewport too.  How can I solve this problem?


I'm a mechanical engineer by training, so please forgive ignorance in my question.  Heisenberg's uncertainty principle states (to my understanding) that one cannot measure both position and momentum to arbitrarily high accuracy, but does this imply (or does this not imply) that one cannot measure one and predict the other?  Consider the following thought experiment. Construct a box with a button and screen on the outside. When the button is pressed, a number between 0 and 1 appears on the screen. Let's suppose that the number on the screen represents the results of an experiment. If a troll is inside the box and uses an algorithm to decide what number is displayed (let's say a pseudo-random number generator), then couldn't someone on the outside of the box theoretically guess what algorithm is being used?  I guess the question I'm asking is: although physics can be accurately described by a stochastic model, does this imply that developing a non-stochastic model is impossible?

I'm not sure if this is the right place to ask this question. I realise that this maybe a borderline philosophical question at this point in time, therefore feel free to close this question if you think that this is a duplicate or inappropriate for this forum. Anyway, I'm an electrical engineer and I have some basic knowledge of quantum mechanics. I know that Schrödinger's equation is deterministic. However, quantum mechanics is much deeper than that and I would like to learn more. If this question is not clearly answerable at this point than can anyone point out some recognized sources that try to answer this question. I would appreciate it if the source is scientific and more specifically, is related to quantum theory.


I read this sci-fi story, which I think was a standalone novel, in the late 1980's - and I don't think it was all that old then. The main character was solitary, at the start of story foraging in a snowed-under grocery store. His name may or may not be Starkman or Starmann; I seem to recall that his eyes were an unusual colour, maybe yellow or amber. The plot involved his DNA containing some kind of hidden message or instructions, put in his ancestor(s) many thousands of years earlier by a (crashed?) alien scientist. Now, others ("bad guys") are looking for it, creating an artificial ice age (via a dust cloud between Earth and the sun, if memory serves) to drive humans to the equator, where they "help" with humanitarian efforts while actually looking for this DNA code. I read a ton of sci-fi stuff back then, so I may be getting things mixed up after this long, but the main plot is right. I'm in Canada, if that helps/matters.

I read this book in the mid-nineties, probably written in the 80s or 90s.  It’s set in the near future, where the world has experienced a sudden glaciation.  Most of the United States and Europe is now covered with ice.  Civilization has collapsed for the most part. The protagonist is a drifter with strange-colored eyes (yellow, I think).  Because of his weird eyes, he’s never really fit in anywhere.  He moves from place to place just trying to survive, but somehow he discovers that the new ice-age did not occur naturally.  It was engineered by extraterrestrials, to make their work easier.  They’re looking for the plans for a super-weapon - a weapon that can cause any star to go nova.  A rival group of aliens hid the plans for this weapon by encoding the information in the human genome millions of years ago.  The marker to identify humans who carry this gene is - you guessed it - yellow-colored eyes.


I am running tmux inside gnome terminal and have been trying to use a binding to copy the contents of tmux's paste buffer to my Linux X clipboard. A lot of places on the internet recommend this:  bind C-c run "tmux save-buffer - | xclip -i -sel clipboard"   This command works perfectly from the command line:  tmux save-buffer - | xclip -i -sel clipboard   If I bind the shell command to a key and use it from inside tmux (using bind C-c run "tmux save-buffer - | xclip -i -sel clipboard"), it does copy the tmux save-buffer to my clipboard; once I have copied some text in tmux's "copy" mode, using this binding will load the text into my X clipboard, ready to be pasted into a browser or anywhere else. However, it _also_  causes the prefix key to stop working for that terminal. If I kill the terminal with tmux running inside it and open another terminal and re-attach to tmux, the prefix key will continue working in another terminal. I also tried the following approach:    Set up an executable file: /usr/local/bin/tmux_to_clip with the command in it  % cat /usr/local/bin/tmux_to_clip  #!/bin/bash  tmux save-buffer - | xclip -i -sel clipboard   and then call the command from inside tmux  :run tmux_to_clip   again, it successfully copies the command to the clipboard, but again it breaks the prefix key. How can I prevent this and get a keybinding for copying tmux save-buffer to the X clipboard?

On mu Ubuntu 12.04 setups my tmux clipboard copy and paste commands are setup as follows:  set -g prefix M-a unbind C-b bind C-c run "tmux save-buffer - | xclip -i -sel clipboard" bind C-v run "tmux set-buffer \"$(xclip -o -sel clipboard)\"; tmux paste-buffer"   This worked great for the longest time up until a month or so ago, when I suspect some configuration change or package change was made that broke the above. In GNOME terminal, pasting still works fine with both prefix+ctrl-v and ctrl-shift-v.   However the xclip copy command no longer works no matter what I do, and I have tried removing the custom prefix binding above, using -select instead of -sel, not using clipboard etc. This is pretty much a show stopper for a GVim user like me, since I don't even have the GNOME terminal workaround of ctrl-shift-c with tmux taking over the shell. I go into copy mode, select text with space+movement, and when I execute prefix+ctrl-c absolutely nothing happens. Before this broke, tmux would display a confirmation message in the notification section at the bottom.  Does anybody have suggestions as far as how one might debug this? This is a pretty big productivity hit. I can probably use the , but it'd be great to know just what happened to xclip.


I'm trying to place an overlay text when hovered over an image but it's not working since the image is already in position absolute, so I can't use relative positioning. I tried to wrap them in a div but the image disappears and shifts from original location. Here's my code and screenshots:

This is a short description

     .image-2{     position: absolute;     margin-top: 3%;     left: 4%;     width: 30%; } .image-3{     position: absolute;     margin-top: 10%;     left: 30%;     width: 20%; } .image-4{     position: absolute;     margin-top: 30%;     right: 30%;     width: 30%; } .content {   position: relative;   width: 90%;   max-width: 400px;   margin: auto;   overflow: hidden; }  .content .content-overlay {   background: rgba(0,0,0,0.7);   position: absolute;   height: 99%;   width: 100%;   left: 0;   top: 0;   bottom: 0;   right: 0;   opacity: 0;   -webkit-transition: all 0.4s ease-in-out 0s;   -moz-transition: all 0.4s ease-in-out 0s;   transition: all 0.4s ease-in-out 0s; } .image-1{         position: absolute;         margin-top: 2%;         top: 0;         right: 0;         width: 35%;     } .content:hover .content-overlay{   opacity: 1; }  .content-details {   position: absolute;   text-align: center;   padding-left: 1em;   padding-right: 1em;   width: 100%;   top: 50%;   left: 50%;   opacity: 0;   -webkit-transform: translate(-50%, -50%);   -moz-transform: translate(-50%, -50%);   transform: translate(-50%, -50%);   -webkit-transition: all 0.3s ease-in-out 0s;   -moz-transition: all 0.3s ease-in-out 0s;   transition: all 0.3s ease-in-out 0s; }  .content:hover .content-details{   top: 50%;   left: 50%;   opacity: 1; }  .content-details h3{   color: #fff;   font-weight: 500;   letter-spacing: 0.15em;   margin-bottom: 0.5em;   text-transform: uppercase; }  .content-details p{   color: #fff;   font-size: 0.8em; }  .fadeIn-bottom{   top: 80%; }  How I display the images in absolute  Edit: As CBroe suggested positioning the wrapper instead of div worked.

I want to overlay one image with another using CSS. An example of this is the first image (the background if you like) will be a thumbnail link of a product, with the link opening a lightbox / popup showing a larger version of the image.   On top of this linked image I would like an image of a magnifying glass, to show people that the image can be clicked to enlarge it (apparently this isn't obvious without the magnifying glass).


Sometimes the OP change something significant in his question which affects my answer.  Is there some way I can be notified when:  A certain question was edited? Question that I answered was edited?

Consider this situation. I post a legitimate and correct answer to a question and receive a few upvotes. Then the OP realizes that's not what they wanted to ask, and significantly rewrites the question, rendering my answer irrelevant and useless. Ideally the OP would comment on every answer saying "check my edit" but some people don't know to do that.  This leaves two possibly bad situations:   I never know, the answer stays, and the votes don't reflect the usefulness of the answer anymore. All of a sudden I get an influx of downvotes because my answer isn't helpful anymore. If I'm checking and notice my rep has dropped, I come back after the fact, edit the answer, and bring it back to the original quality. This is great, but 9 times out of 10, the downvoters never come back and notice the answer has been edited. It might get more upvotes, but it still doesn't reflect the true value of the answer.   If we can get notified when the OP gets edited, we can nip it in the bud and go back to edit our answers to match - thus maintaining the quality of the answers on SO.


I am reading a proof of the Cayley-Hamilton theorem which uses the fact that $adj(A)A=det(A)I$, where I is the $n\times n$ identity matrix and $A\in M_n(\mathbb{F})$ for a field $\mathbb{F}$.  Could you indicate me a quick way of proving this or to a reference proving it ?  And is is true for a matrix with coefficients over any commutative ring ? I would guess so because C-H is true for any commutative ring. In this case, is the proof the same ?  Thanks

This is a statement in linear algebra that I can't seem to understand the proof behind.  For a square matrix $A$, why is: $$\mathrm{adj}(A)A = \det(A) \cdot I$$  Any explanation would be greatly appreciated.


I need to know where are the saved webpages of Google Chrome stored in Android.  I mean, I can access them from the browser itself but I need to know where its stored in the file manager.

I opened the following page:   When disconnecting WiFi and even after rebooting the mobile phone, the page can still be read due to being saved automatically.  Left to the URL bar, an indicator looks like this:  This also shows up when opening manually saved pages, which are saved as MHTML files in the default download folder.  However, an automatically saved page can not be re-downloaded manually to get to the download folder, because the arrow is greyed out.I wish to copy some automatically saved pages into the download folder.  Where are the files of automatically saved pages stored?


I have this general question. Imagine someone has eyesight: -1.75. (He is nearsighted) Now, if this person doesn't wear glasses, will the eyesight get worse because of this? In other words is wearing glasses optional for such people?

I've been told that wearing eyeglasses to correct poor vision can cause your vision to degrade even further. In other words, "Hold off wearing glasses for as long as possible, because once you start, it gets much worse."  The claim is that with glasses, the eyes don't have to work as hard to focus and then become "lazier" (for lack of a better term), leading to a vicious cycle of needing more and more correction.  Is there any truth to this claim?


I searched for a module provide notification like one exist in facebook website. I found  but it's for D6. is There a module can i use for what i need?  thanks.

Using Heartbeat I have been able to effectively make streams of user activities through Rules triggers. However I would like to be able to have users notified of new activities, and keep a count of the number of new activities like in facebook, or even similar to new email counts in most email systems.   In Drupal 6 there were a few modules which could achieve this well, however how can this be done in Drupal 7?  I have done quite extensive research on this but am unable to find the right module at this point: There's the  and  modules, which would be the perfect solutions except only D6 versions exist. There's  which cannot be integrated with any activity logging module since it lacks proper Rules support. Two interesting implementations are  and  which provide dropdown trays with lists of activities, but don't count the number of new activities and no longer integrate with Rules. Finally  is great as a dynamic counter, even though at the moment it only counts Flags and provides a link to a list of the flagging users. Perhaps with some tweaking it could be used via Flags Rules integration to track recent (flagged) activities and link to a list of these recent activities.  Is it possible to achieve functionality similar to this in Drupal 7?


thanks for attention, I struggled with such issue: I packed a JAR file with external libraries in Intellij Idea but when I am trying to lounch it, I see error:    The file "city-data.json" is missing or inaccessible, make sure the URL is valid or that the file has been added to your sketch and is readable. Exception in thread "Animation Thread" java.lang.NullPointerException         at processing.core.PApplet.join(PApplet.java:8950)         at de.fhpotsdam.unfolding.data.GeoJSONReader.loadData(Unknown Source)         at Map.setup(Map.java:45)         at processing.core.PApplet.handleDraw(PApplet.java:2361)         at processing.core.PGraphicsJava2D.requestDraw(PGraphicsJava2D.java:240)         at processing.core.PApplet.run(PApplet.java:2256)         at java.lang.Thread.run(Unknown Source)   But I see this file in this Jar   When i lounch project from Intellij or Eclipse all works good. Please, help, what problem it can be.  Also i will be very grateful if somebody tell, how I can to collect all project to Jar file from the command line. I tried to make it with the help of commands such as   jar cvfe MyJarName.jar MyMainClass *.class   but it don't work too, command line answered with a lot of errors like

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


i have a list view contains the locations coordinate (late,long) and i'm trying to pass them to a map activity to show it on map   this is on android studio and Kotlin  listView.setOnItemClickListener { parent, view, position, id ->          val time = usersList.get(position).time         val long:String = usersList.get(position).long         val late :String = usersList.get(position).late startActivity(Intent(this, MapsActivity2::class.java).putExtra("long",long).putExtra("late",late)) }     class MapsActivity2 : AppCompatActivity(), OnMapReadyCallback {  private lateinit var mMap: GoogleMap  var long:String = intent.getStringExtra("long") var late:String = intent.getStringExtra("late")   override fun onCreate(savedInstanceState: Bundle?) {     super.onCreate(savedInstanceState)     setContentView(R.layout.activity_maps2)       // Obtain the SupportMapFragment and get notified when the map is ready to be used.     val mapFragment = supportFragmentManager         .findFragmentById(R.id.map) as SupportMapFragment     mapFragment.getMapAsync(this) }   override fun onMapReady(googleMap: GoogleMap) {     mMap = googleMap      // Add a marker in Sydney and move the camera     val sydney = LatLng(long.toDouble(), late.toDouble())     mMap.addMarker(MarkerOptions().position(sydney).title("jh"))     mMap.moveCamera(CameraUpdateFactory.newLatLng(sydney)) } }      Process: com.example.firebase, PID: 32463       java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.firebase/com.example.firebase.MapsActivity2}: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.content.Intent.getStringExtra(java.lang.String)' on a null object reference           at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3289)           at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3548)           at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:86)           at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)           at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)           at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2155)           at android.os.Handler.dispatchMessage(Handler.java:109)           at android.os.Looper.loop(Looper.java:207)           at android.app.ActivityThread.main(ActivityThread.java:7539)           at java.lang.reflect.Method.invoke(Native Method)           at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:524)           at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:958)        Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.content.Intent.getStringExtra(java.lang.String)' on a null object reference           at com.example.firebase.MapsActivity2.(MapsActivity2.kt:19)           at java.lang.Class.newInstance(Native Method)           at android.app.AppComponentFactory.instantiateActivity(AppComponentFactory.java:69)           at android.support.v4.app.CoreComponentFactory.instantiateActivity(CoreComponentFactory.java:43)           at android.app.Instrumentation.newActivity(Instrumentation.java:1224)           at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3274)


Let $f:X \to Y$ be a proper map.Show that $f$ takes discrete sets to discrete sets.  Proof:Let $A$ be discrete in $X$ and let $K$ be compact in $Y$ then $f(A) \cap K=f(A \cap f^{-1}(K))$,is finite since $A \cap f^{-1}(K)$ is finite.Hence $f(A)$ is discrete  But @Alex Ravsky here  gave  a counter example. So can Someone please point out the flaw in my proof?

Suppose $f:X \to Y$ is a continuous proper map between locally compact Hausdorff spaces. Are the following results true?  $1$. The map $f$ takes discrete sets to discrete sets.  $2$. If $f$ is injective, then $f$ must be a homeomorphism onto its image.  Edit1:Let $A$ be discrete in $X$ and let $K$ be compact in $Y$ then $f(A) \cap K=f(A \cap f^{-1}(K))$,is finite since $A \cap f^{-1}(K)$ is finite.Hence $f(A)$ is discrete. As there is a counterexample in answer below so can someone please point out the error in my proof?


I am trying to only allow port 22 TCP/UDP and port 80 TCP/UDP from anywhere using Fedora 15 iptables, and all the rest will be never accessible nor scannable from a public network.   But it never works for me, at the end I turned it off because I am scared it will block me to access even the port 22 myself.  So, my question is, how can I do this in Fedora 15? Block all except for 22, 80 TCP/UDP?  iptables -P INPUT ACCEPT  # Fresh start iptables -F # Localhost/ethernet 0 / yum installation allow iptables -A INPUT -i lo -j ACCEPT iptables -A INPUT -i eth0 -j ACCEPT iptables -A INPUT -m state –state ESTABLISHED,RELATED -j ACCEPT  # SSH iptables -A INPUT -p tcp –dport 22 -j ACCEPT #iptables -A INPUT -s aa.bb.aa.bb -d xx.yy.xx.yy -p tcp -m tcp –dport 22 -j ACCEPT iptables -A INPUT -d xx.yy.xx.yy -p tcp -m tcp –dport 22 -j ACCEPT  # other iptables -P INPUT DROP iptables -P FORWARD DROP iptables -P OUTPUT ACCEPT  # show iptables -L -v

How can I block all ports except:  ssh (port 22) httpd (port 80)  using iptables and ipchains?


I am working on an image processing project. For that I have a directory which contains around 70,000 images. As I process them in multiple stages I save the intermediate images in another directory. But when I want to see it I can't, as when I open the directory, due to the number of files the file manager stops responding. Even if I somehow manage to open it, I fear that the image viewer will not respond, as I am under the impression that they try to put a few images in cache to load faster. I tried to open the images from terminal. I can open one image at a time in this case but I can't view it as a gallery, which is equally bad as I need to view many images to know that the results are satisfactory.

I have a large library of PDF documents (papers, lectures, handouts) that I want to be able to quickly navigate through. For that I need thumbnails. At the same time however, I see that the ~/.thumbnails folder is piling up with thumbs I don't really need. Deleting thumbnail junk without removing the important thumbs is impossible. If I were to delete them,  I'd have to go to each and every folder with important PDF documents and let the thumbnail cache regenerate. I would love to be able to automate this process. Is there any way I can tell nautilus to pre-cache the thumbs for a set of given directories? Note: I did find  that appear to do this for pictures and videos, but not for any other documents. Maybe someone more experienced with scripting might be able to adjust these for PDF documents or at least point me in the right direction on what I'd have to modify for this to work with PDF documents as well.  Edit: The response to this question has been quite overwhelming. Let me first thank everyone who participated in solving this. The question, its answers and all the discussion around it are a great example of how the collaborative effort of many parties can lead to an optimal solution. This is exactly what makes Linux and Open Source so great. All of the provided answers would deserve the bounty I originally put up for this question. Still, there's only one bounty to award. I owe it to all future readers to choose the answer that solves the problem in the most efficient way. To determine which solution that is, I did a final test run, comparing the three scripts in compatibility, speed and output quality. Here are the results:  Thumbnailer 1, by rosch: Compatibility: ✔ spaces in file name ; ✔ spaces in directory name ; ✘ freedesktop compliant Speed: 95 PDFs in 12,6 sec Quality: stock nautilus quality Additional Perks: 1.) automatically skips files with preexisting thumbs ; 2.) No additional packages needed Thumbnailer 2, by Martin Orda: Compatibility: ✔ spaces in file name ; ✔ spaces in directory name ; ✘ freedesktop compliant Speed: 95 PDFs in 70,0 sec Quality: significantly better scaling than the stock images. Additional Perks: 1.) automatically skips files with preexisting thumbs 2.) compatible with a wide range of image formats besides PDF 3.) platform-independent, does not rely on GNOME-components Thumbnailer 3, by James Henstridge: Compatibility: ✔ spaces in file name ; ✔ spaces in directory name ; ✔ freedesktop compliant Speed: 95 PDFs in 10,8 sec Quality: stock nautilus quality Additional Perks: 1.) automatically skips files with preexisting thumbs 2.) compatible with all file formats that are identified by the preinstalled thumbnailers  All three scripts are excellent. Each has its distinct set of advantages and disadvantages.  works out of the box and might be the right choice for users with a minimal installation. Marcin Kaminski created a very  that works with a variety of file formats and is DE-independent. It excels at thumbnail quality but does so at the expense of speed. In the end it was  that fit my use case best. It's fast, versatile and offers the options to skip over files with preexisting thumbnails.  Overall winner: James Henstridge  Additional information: All three scripts are fully compatible with nautilus-scripts. You can easily install them .  Edit 2: Updated review with improved script by rosch.


I was told that I live my life by the seat of my pants, and though it doesn't sound like a compliment, I'm not sure that it is an insult either.  What is the derivation of "seat of my pants"?

Where does the expression seat-of-the-pants come from? These dictionaries (, , ) don't give much insight.  What is the etymology of seat-of-the-pants?


I'm making a website for my brother's webcomic, which was previously hosted on Tumblr. What is the most efficient/logical option for storing the pictures?   Downloading and putting the path in the Db Storing them in the database, base64-encoded linking directly to the pictures on Tumblr   wat do?

So I'm using an app that stores images heavily in the DB. What's your outlook on this? I'm more of a type to store the location in the filesystem, than store it directly in the DB.  What do you think are the pros/cons?


O/S; Ubuntu 19.10 on AMD (Ryzen5). Objective; To play .mp4 video clips. Steps taken:  Ran: sudo apt install libdvdnav4 libdvdread4 gstreamer1.0-plugins-bad gstreamer1.0-plugins-ugly libdvd-pkg  The install seemed to have proceeded without any problems, but the Terminal screen then filled with the following, became totally unresponsive & required a New Tab to progress.   Attempted to run instruction from screenshot: sudo dpkg-reconfigure libdvd pkg  This resulted in an error message saying: debconf: DbDriver "config": /var/cache/debconf/config.dat is locked by another process: Resource temporarily unavailable   Attempted to run sudo apt install ubuntu-restricted-extras  resulting in error message: E: Could not get lock /var/lib/dpkg/lock-frontend. It is held by process 5777 (dpkg) - open (11: Resource temporarily unavailable) N: Be aware that removing the lock file is not a solution and may break your system. E: Unable to acquire the dpkg frontend lock (/var/lib/dpkg/lock-frontend), is another process using it?   Attempting to uninstall/purge resulted in another error message saying 'dpkg was interrupted, you must manually etc, etc' and to run: sudo dpkg --configure -a    Running this resulted in the same unresponsive Terminal screen as above . Any advice on how to proceed from here would be most appreciated.

I'm trying to install the flashybrid but when I enter the apt-get install flashybrid command, I get this error:  root@user-desktop:/home/user# apt-get install flashybrid Reading package lists... Done Building dependency tree Reading state information... Done flashybrid is already the newest version. 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. 1 not fully installed or removed. After this operation, 0B of additional disk space will be used. debconf: DbDriver "config": /var/cache/debconf/config.dat is locked by another process: Resource temporarily unavailable Setting up flashybrid (0.15+nmu2) ... debconf: DbDriver "config": /var/cache/debconf/config.dat is locked by another process: Resource temporarily unavailable dpkg: error processing flashybrid (--configure): subprocess post-installation script returned error exit status 1 Errors were encountered while processing: flashybrid E: Sub-process /usr/bin/dpkg returned an error code (1)   I also tried this one to find what is already using that file:  root@user-desktop:/home/user# lsof | grep /var/cache/debconf/config.dat lsof: WARNING: can't stat() fuse.gvfs-fuse-daemon file system /home/user/.gvfs Output information may be incomplete. dpkg-prec 4672 root 4rW REG 8,6 39658 1697827 /var/cache/debconf/config.dat   But I don't know how to fix this.