Ubuntu 18.04 LTS shows that update cannot be done securely due to lack of Release File

I'm trying to upgrade my Ubuntu 18.04 LTS to Ubuntu 20.04 LTS. However, when I type in sudo apt update in the terminal, I get: Hit:1 https://repo.skype.com/deb stable InRelease Hit:2 http://ppa.launchpad.net/maarten-baert/simplescreenrecorder/ubuntu bionic InRelease Hit:3 http://dl.google.com/linux/chrome/deb stable InRelease                    Hit:4 http://archive.ubuntu.com/ubuntu bionic InRelease                         Hit:5 http://archive.canonical.com/ubuntu bionic InRelease                      Hit:6 http://ppa.launchpad.net/nathan-renniewaldock/flux/ubuntu bionic InRelease Hit:7 http://security.ubuntu.com/ubuntu bionic-security InRelease               Hit:8 http://archive.ubuntu.com/ubuntu bionic-updates InRelease                 Hit:9 http://archive.ubuntu.com/ubuntu bionic-backports InRelease               Ign:10 http://ppa.launchpad.net/vikoadi/ppa/ubuntu bionic InRelease       Err:11 http://ppa.launchpad.net/vikoadi/ppa/ubuntu bionic Release                404  Not Found [IP: 91.189.95.83 80] Reading package lists... Done                       E: The repository 'http://ppa.launchpad.net/vikoadi/ppa/ubuntu bionic Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.  Is there any workaround for this?


side channel attack on RSA implementation

What classes of side-channel attacks are applicable to RSA implementation and what is the efficiency rate ?


Is it common for native speakers to put a question mark at the end of declarative sentence?

Sometime, people put a question mark at the end of a sentence and use it to ask something. Instead using an interrogative sentence:     Do you like it?   You like it?   I think it is more often to someone who is not good at English.  As I am Korean, however, I realized that I also often and frequently violate Korean grammar. And I can't keep that all.  So, my question is:   Is it common for the native to use a declarative sentence as interrogative? Is it hard to understand in a short time? How are your societies tolerant to this?   Is this regarded as impolite or rude?


It looks there is a problem with TexShop and multibib package. multibib package expects that you do bibtex xxx where xxx is your own newcites. However, when using TexShop it looks like it only does it for the main document. Therefore, the only way I have to make it work is to do it from command line (notice the bibtex xxx):   pdflatex main  bibtex main  bibtex xxx  pdflatex main  pdflatex main   Do you know a workaround I can do so that I can latex without problem in any IDE?  Thanks!


A few months ago on a flight, I stupidly put a glass of wine next to my immaculate Macbook. The inevitable happened and half a glass of red wine was split directly onto the keyboard. In a combined two handed move which I now call the "Macbook Save", I held down the power button to turn it off and tipped the Macbook to the side and the wine ran out of the keyboard.   I cried a little and then left it switched off in my bag until I got home two weeks later. I was surprised to find that it was in full working order but the U key has been a little temperamental. Today I took the key cover and butterfly mechanism out to find the culprit of my intermittent key, some red wine staining.   Is this slightly rubbery part removable? I'd rather not force it and break a nearly perfectly functioning keyboard. If not I was going to try to get some tiny amounts of pure alcohol under there to try and remove the red wine deposits. Is this a terrible idea? Looking at keyboard replacement videos I can see how it managed to survive relatively unscathed as the keyboard looks glued in!


Can i move the second exists to the left in this formula?

Is it legal to change  $\exists$x A(x) $\implies$ $\exists$y B(y)  to:  $\exists$x $\exists$y (A(x) $\implies$  B(y))  If i'm thinking correctly, A(x) is free from $\exists$y and should be allowed to move. However i am not able to prove it. So far i have:  $\neg$$\exists$x A(x) $\vee$ $\exists$y B(y)  $\forall$x $\neg$A(x) $\vee$ $\exists$y B(y)  $\forall$x $\neg$A(x) $\vee$ $\neg$$\forall$y $\neg$B(y)  $\forall$x ($\neg$A(x) $\vee$ $\neg$$\forall$y $\neg$B(y))  $\forall$x $\neg$ $\forall$y($\neg$A(x) $\vee$ $\neg$B(y))  $\neg$$\exists$x $\forall$y($\neg$A(x) $\vee$ $\neg$B(y))  $\neg$$\exists$x $\forall$y(A(x) $\wedge$ B(y))  $\neg$$\exists$x $\neg$$\exists$y $\neg$(A(x) $\wedge$ B(y))  $\neg$$\exists$x $\neg$$\exists$y ($\neg$A(x) $\vee$ $\neg$B(y))  $\neg$$\exists$x $\neg$$\exists$y (A(x) $\implies$ $\neg$ B(y))  I'm likely to have mistakes here, have not touched this in a while.


So I want to build a little "setup" with a led strip, using an arduino and a seperate psu to power the led strip. The psu outputs 12v 5A dc. Before I start connecting anything and might hurt myself, is the output of the psu deadly? I want to connect the the psu to the led strip through one of these: ?. Any help would be highly appreciated. (Not very known with electricity)


Using entity metadata wrapper with custom entity type

I've created custom entity. In addition I want to add user reference field to my entity:  if (! field_info_field(MY_FIELD_NAME)) {   // Create the field.    $field = array(     'field_name' => MY_FIELD_NAME,     'type' => 'entityreference',     'cardinality' => FIELD_CARDINALITY_UNLIMITED,     'settings' => array(         'target_type' => 'user',         'handler' => 'base',         'handler_settings' => array(             'target_bundles' => array()         ),     ),     'bundles' => array (         MY_ENTITY_NAME =>             array (                 0 => MY_ENTITY_BUNDLE_NAME,             ),     ), ); field_create_field($field);      // Create the instance.     $instance = array(         'field_name' => MY_FIELD_NAME,         'entity_type' => MY_ENTITY_NAME,         'bundle' => MY_ENTITY_BUNDLE_NAME,         'label' => '',         'description' => '',         'required' => TRUE,         'widget' => array(),         'display' => array(             'default' => array(                 'label' => 'hidden',             ),         ),     );      field_create_instance($instance); }   In form submit I want to add users references to this field:     foreach($result as $recipient) {         $wrapper->{MY_FIELD_NAME}[] = $recipient->uid;     }   I gets:     Fatal error: Cannot use object of type EntityDrupalWrapper as array   What I am missing?


top (table of processes) package on Ubuntu 16.04 LTS

When I run sudo apt install top, I get E: Unable to locate package top  I searched  for  package on 32 bit Ubuntu 16.04 LTS, but there is none.   I wonder if it's correct or I'm missing something.


How to specify default options for figure environment?

More specifically, how can I set in the preamble the default options for the figure environment to [htb]? I am trying to separate content from format as much as possible and want to avoid writing \begin{figure}[htb] every time I declare a figure.


I know that hardly any information is passed to the PDF when a .tex file is compiled.  But is there a tool that can convert a PDF document back to (La)TeX?


Question asks find the sum of the series.  Firstly i tried to use geometric series formula to calculate sum but could not convert it to geo form. $$ ar^{n-1} $$ So should we transform equation into geo form or use another method to calculate sum?  This is the equation i try to calculate sum.  $$\sum_{n=0}^∞ = \frac{1}{(n+1)2^n}$$


Android: Null object reference in adapter for for recyclerview

Trying to create a recyclerview for displaying data from the db. Keep getting this null pointer error on the same line. According to other sources, its because I do not instantiate the arraylists, so I fixed that I guess. I'm trying to make a simple book library, just as an example to use it later on my college project. The null pointer exception occurs on line 36, where the book author's position is passed to get() package com.example.sql_recyclerview; import android.content.Context; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.TextView; import androidx.annotation.NonNull; import androidx.annotation.RequiresApi; import androidx.recyclerview.widget.RecyclerView; import org.w3c.dom.Text; import java.util.ArrayList;     public class CustomAdapter extends RecyclerView.Adapter<CustomAdapter.MyViewHolder>     {         private Context context;         private ArrayList book_id, book_title, book_author, book_pages;         CustomAdapter(Context context, ArrayList book_id, ArrayList book_title, ArrayList book_author, ArrayList book_pages)         {             this.context = context;             this.book_id = book_id;             this.book_title = book_title;             this.book_pages = book_pages;         }         @NonNull         @Override         public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType)         {             LayoutInflater inflater = LayoutInflater.from(context);             View view = inflater.inflate(R.layout.my_row, parent, false);             return new MyViewHolder(view);         }         @Override         public void onBindViewHolder(@NonNull MyViewHolder holder, int position)         {             holder.book_id_txt.setText(String.valueOf(book_id.get(position)));             holder.book_title_txt.setText(String.valueOf(book_title.get(position)));             holder.book_author_txt.setText(String.valueOf(book_author.get(position)));             holder.book_pages_txt.setText(String.valueOf(book_pages.get(position)));         }         @Override         public int getItemCount()         {             return book_id.size();         }         public class MyViewHolder extends RecyclerView.ViewHolder         {             TextView book_id_txt, book_title_txt, book_author_txt, book_pages_txt;             public MyViewHolder(@NonNull View itemView)             {                 super(itemView);                 book_id_txt = itemView.findViewById(R.id.book_id_txt);                 book_title_txt = itemView.findViewById(R.id.book_title_txt);                 book_author_txt = itemView.findViewById(R.id.book_author_txt);                 book_pages_txt = itemView.findViewById(R.id.book_pages_txt);             }         }     }


"All the good people" vs. "all of the good people"

I've heard both of these before.        All the good people   All of the good people      Are they both correct?


Define new commands which use line-break as delimiter instead of curly braces

I would like to use commands without having curly braces {} as delimiters.  Mostly I would like that the commands work with a line-break as the delimiter.  Herewith a simple example, which does not work (My is displayed but missing the line)  \documentclass[12pt]{report} \def\chap #1 {\chapter{#1}} \def\sec #1 {\section{#1}} \def\subsec #1 {\subsection{#1}} \def\li #1 {\begin{itemize}\item #1\end{itemize}} \begin{document} \chap My First Chapter \sec My First Section \subsec My First Section \li lkdsjfaljsfad \li lkdsjfaljsfad \li lkdsjfaljsfad \end{document}   Would you know how to make it work?


This question seems a lot like one of those "Phylosoraptor" memes all over the Internet, and it might be very silly, but I've been thinking about this for a while.  Is it possible that space is not actually expanding but rather, the speed of light is decreasing throughout the entire Universe? ...as if light were traveling through a medium that would be changing its properties over time.  I guess there are several phenomenons that can be explained just as well by assuming that either space is expanding, either light is slowing down, but I do not know enough physics (and phenomenons that could contradict such a claim) in order to rule out this possibility.


I'm really sick of getting all of my items destroyed when I die.  Is there any way, even by cheating, to re-acquire the items or to disable the ?


How many integer solutions does $xy+9(x+y)=2006$ have? Here $x$ and $y$ are both integers.  My trying:        I have tried to solve this problem. But I have no idea to solve this. Please help


Is there an error in this question on vector addition and subtraction?

Is there an error in this question?  Let u = $(1,0,2)$, v = $(2,1,0)$ and w = $(0,2,1)$. Compute  ||u + v - w.||v = v  This is exactly what is in the question (even the dot after w which I don't know what it means).  Thanks


Is there a way to record your 3dconnexion as your final camera movement?

Beginner question. I've got 3Dconnexion working great and moving all around my model in user perspective. How do I to assign/record those smooth 3dconnexion movements and attach them to my camera so the animation is buttery smooth?


Read/write to Windows registry using Java

How is it possible to read/write to the Windows registry using Java?


Comparing a sequence of fractions with a fraction

Let's assume that every a belongs to real numbers set and s is a sum of all the numbers from $a_1, a_2...a_n$. How would you prove this?  $\frac{a_1}{s - a_1}$ + $\frac{a_2}{s - a_2}$ ...+$\frac{a_n}{s - a_n}\ge \frac{n}{n - 1}$


Placing a figure in one-column within a two-column document

This is the code in which I have the texts in two-column mode,  but I want the figure to be placed in one-column  without a page-break   \begin{figure}[ht] \onecolumn\includegraphics[width=\columnwidth]{Capture.PNG}   \caption{A system}   \label{fig:1}  \end{figure} \twocolumn


"If you were to do" compared to "If you did"

If they were to cancel the deal, I would be devastated. If they canceled the deal, I would be devastated.  My thextbook says, the "if ... were to" construction gives much less probability for something to happen. But an American said to me that it is not, he does not perceive it when he hears it.


Changing the text color for a cell does change alignment

If i color the text of a table cell, the text gets aligned wrong.  Without color:    With color:    MWE:  \documentclass[10pt, handout]{beamer}  \usepackage{tabulary} \usepackage{xcolor}  \begin{document}     \begin{frame}{Test}         \begin{tabulary}{\textwidth}{LLLL}             test & test & test & test \\             test & \color{red}test & test & test \\         \end{tabulary}     \end{frame} \end{document}     I want to use it in a way like this:  \newcommand{\highlight}{\color{black}\cellcolor{red}}  \begin{tabulary}{\textwidth}{LLLL}     test & test & test & test \\     test & \highlight test & test & test \\ \end{tabulary}


I have the following sentence:  "To tackle climate change, it is important to reduce the CO2 emissions significantly"  An other option would be to use the adverb before the verb like:  "To tackle climate change, it is important to significantly reduce the CO2 emissions "  What is your take on that? I'd appricate every answer. Thanks in advance.


Very new to Java and programming in  general. trying to figure out how to print the contents of my array  public class GameClass {     public static void main(String args[]) {         String [] gameList = new String [] {"Call of Duty", "Skyrim", "Overwatch", "GTA", "Castlevania", "Resident Evil", "HALO", "Battlefield", "Gears of War", "Fallout"};         System.out.println(gameList[]);     } }


I'm just about to embark on my first brew with my dad.  He mentioned that he may include half a tea spoon of sugar into each of the bottles to prevent it becoming flat.  What are other suggestions to avoid adding processed sugar to a bottle whilst still maintaining that liveliness?  ------- Edit  I have found this:   Sorry for the duplicate post.


On an example in Macdonald's Symmetric Functions and Hall Polynomials on Paritions and their Frobenius Notation

I am following Macdonald's Symmetric Functions and Hall Polynomials, and in his example-section. He stated the following without any proof, and I'm trying to understand how he reached the expression. Any assistance will be appreciated.   A partition $\lambda = (\lambda_1, \lambda_2, \cdots, \lambda_n)$ can be written in the Frobenius notation $(\alpha_1,\cdots,\alpha_r \ \vert \ \beta_1,\cdots,\beta_r)$, where $\alpha_i = \lambda_i - i$, $\beta_i = \lambda'_i - 1, \ $ $(1 \leq i \leq r)$. $r$ is the length of the intersection of the young diagram of $\lambda$ with the diagonal $i=j$.  Essentially, in the Young Diagram of $\lambda$, if we discard the diagonal, which contains $r$ squares, counting left to right to the right of the diagonal gives us $\alpha$, and counting downwards to the left of diagonal gives us $\beta$.  Macdonald states: $$\sum_{i=1}^{n}t^i\big(1-t^{-\lambda_i}\big)=\sum_{j=1}^{r}\big(t^{\beta_j + 1}-t^{-\alpha_j}\big)$$


public void searchSong(String songToSearch){     Toast.makeText(getApplicationContext(), songToSearch, Toast.LENGTH_SHORT).show();     boolean found = false;     for(int i = 0; i < fileArray.length; i++ ){         String value = fileArray[i].toLowerCase().replace(".mp3","");         if (songToSearch.toLowerCase().matches(value) && !found) {             Toast.makeText(getApplicationContext(), value, Toast.LENGTH_SHORT).show();             found = true;         } else {             found = false;         }         if(found){             Toast.makeText(getApplicationContext(), "Found", Toast.LENGTH_SHORT).show();         }     } }   I want to use the code to check if the songToSearch is a part of any string inside the fileArray  Example lets say that fileArray[2] is equal to "Hello world" and the songToSearch is equal to "world" I would like to make the boolean found true... However this is not happening... the boolean never changes


Prove that convergence of $\sum a_n$ implies convergence of $\sum \frac{\sqrt{a_n}}{n}$ if $a_n\geq 0$  My solution is a little bit messy. I found easy solution , but can anyone please tell if my argument is right or not?  Three type of cases can happen:  case 1: $\exists N: \forall n\geq N$ such that, $a_n\geq \frac{\sqrt{a_n}}{n}$. I this case the solution is immediate.  case 2: $\exists N: \forall n\geq N$ such that, $a_n\leq \frac{\sqrt{a_n}}{n}$. In this case note that, $\frac{\sqrt{a_n}}{n}\leq \frac{1}{n^2}$. Again converges.  case 3: $\nexists N: \forall n\geq N$ such that, neither $a_n\geq \frac{\sqrt{a_n}}{n}$ nor $a_n\leq \frac{\sqrt{a_n}}{n}$ happens. In that case, we divide the sequence such that for some $n$, $a_n\geq \frac{\sqrt{a_n}}{n}$ and for some $n$, $a_n\leq \frac{\sqrt{a_n}}{n}$. Then, case 3 is actually a combination of case 1 and case 2. Hence the series converges in this case too.  Hence, $\sum \dfrac{\sqrt{a_n}}{n}$ converges if $a_n\geq 0$


Wordpress - Non-www URL redirect to www using .htaccess file

I want to redirect non-www URL to www URL in WordPress.  I added code for the redirect but I see that I only redirect URL internally but not accessible from the externally. I redirect to apache default page  I added coed in .htaccess.  <IfModule mod_rewrite.c>     RewriteEngine On     RewriteCond %{HTTP_HOST} !^www\. [NC]     RewriteRule ^(.*)$ http://www.%{HTTP_HOST}/$1 [R=301,L] </IfModule>   Not work externally. I also set www in secure/non-secure URL.  Does have any solution?


I'd like to clear recent inputs in terminal not cls or clear but when you press up or down. How do I clear this list so that when I rename sudo to nodood or something you cannot press up to view the new sudo perhaps my script will read input.   EDIT: Note pressing Ctrl + R in terminal will let you search history like history | grep searchQueryString  Another useful tip is  sudo !!  which re-executes last command with sudo prefixed


18.04 - Can't Get 64 bit Ubuntu on my Intel Core i7-6500u to start in Oracle Virtual Box

try to start and get Kernel requires x86-64 CPU, but only detects i686


Why is the amplitude of a forced vibration lower above resonance than below?

Am I correct in thinking that for a given harmonic oscillator, with constant magnitude driving force, the resultant amplitude of the steady-state motion will be generally lower above resonance than below.  If this is the case then is there a reason for this.


In the Avengers movie, Dr. Banner is discovered treating patients for some unspecified, possibly unknown, disease in what looks to be the slums of India. From my recollection, Banner is a gamma physicist and not a medical doctor (Ph. D not M.D.). While it can be argued that the Indians may or may not know the difference, Banner hardly seems the type to con people for a quick buck.


dimension of a direct sum is the sum of the separate dimensions

Suppose $U$ is a finite dimensional vector space and $U$ can be expressed as a direct sum $U=U_1\oplus\dots\oplus U_n$. Then $\dim(U) = \dim(U_1) + \dots + \dim(U_n)$.    I don't really have any idea how to prove this, any tips?


I'm on Ubuntu 16.04 and I notice that in the "Additional Drivers" tab of "Software & Updates", the latest versions of NVIDIA drivers I can install are   version 367.57 from nvidia-367 (proprietary) version 370.28 from nvidia-370 (open source)   Aside from the fact that I don't know what "proprietary" and "open source" mean here, I also don't see an option to select the driver version based on my actual graphics card. I'm using GTX 1080 and the current Long Lived Branch version is 375.20; will the Ubuntu graphics PPA be updated eventually, or will I have to manually install 375?


I am doing PCA using Matlab's pca() function and R's prcomp() function. They give identical principal components in some cases and  same values and opposite sign in some other cases. Why is this happening?  P.S : I am not asking about the interpretation.


Can Darkness be cast on a part of an object?

The  spell can be cast on small objects, and can be covered, but can it be cast on the blade of a dagger, and covered by sheathing the dagger and leaving the rest bare?   Or do I have to cast darkness on the entire dagger, and keep the dagger covered in a cloth or pocket?  Alternatively, are pieces of whole objects valid targets for spells?  What defines an "object"?  Is a blade separate from a hilt?  Is my ring separate from my hand?


Flea hopping on triangle combinatorial solution

So the problem is this: A flea hops about at random on the vertices of a triangle. Find the probability that after $n$ hops the flea is back where it started.  So let $X_n$ be the position of the flea at the $n$th hop. I want to find $P(X_n = 1 | X_0 = 1)$.   Now \begin{align} p_{1,1}(n) = P(X_n = 1 | X_0 = 1) &= \displaystyle \sum_{k=1}^3 P(X_n = 1|X_1 = k, X_0 = 1)P(X_1 =k|X_0 = 1)  \\&=\sum_{k=1}^3 P(X_{n} = 1|X_1=k) P(X_1=k|X_0=1) \\&= \sum_{k=1}^3 P(X_{n-1}=1|X_0=k)P(X_1=k|X_0=1) \\&= \sum_{k=1}^3 p_{1,k}(n-1)p_{k,1}(1) \\& = \sum_{k_1,\cdots,k_{n-1}} p_{1,k_1}(1)p_{k_1,k_2}(1)\ldots p_{k_{n-1},1}(1) \end{align}  So I just need to find the $(1,1)$ entry of $\begin{pmatrix} 0 &1/2&1/2\\ 1/2 & 0 & 1/2\\ 1/2 & 1/2 & 0\\ \end{pmatrix}^n$ which after diagonalising and a lot of work turns out to be $\dfrac 1 3 \left(1 + \dfrac{(-1)^n}{2^{n-1}}\right)$.  Obviously there is a nicer combinatorial way of deriving this expression, but I'm rubbish at this kind of thing. Please help.  Please read the FULL question before marking as duplicate. Is this question going to get reopened then or shall I ask it again?


Are both "I have been reading an hour already" and "I have been reading for an hour already" correct?  Or "I have been working here 3 years" and "I have been working here for 3 years"?


What sci-fi short story featured a man waking up from stasis several times over millennia?

I read this story in a sci-fi anthology in the mid 90s, but I remember thinking the book looked pretty old by then.  The story is about a man who wakes up from stasis / cryogenic sleep in the future, only to discover that he's the only human left alive on Earth. He's greeted by a simple robot which is programmed to follow his instructions. He spends some time in the library, but eventually decides to go back to stasis. Before he does, he gives the robot an order, which it interprets to mean that it should expand its own capabilities.  When the man wakes up again next time, many years have passed, possibly centuries, and the robot is noticeably smarter, having gained several extensions and upgrades. For some reason, the man goes back to stasis.  That keeps happening a few times, the man goes in and out of stasis, and every time he wakes up the robot has upgraded itself. Eventually the man gets so depressed about being the only human left that he decides to go back to stasis permanently.  The next time he wakes up, billions of years have passed and Earth is about to end. The robot, who by now is on the far side of the singularity, ushers him into a spaceship and puts him back to sleep.  The man wakes up a final time,       on a planet full of humans. The robot has spent the time when he was in stasis to find a new planet, terraform it, and create human beings to populate it. The twist is that everyone has a green tint, because they were modeled on a discolored picture of the man's wife, that he had in his wallet. The man decides he's fine with this.   I can't remember exactly why all the other humans were dead, could have been a war or a plague or something similar. I also can't remember why he went in and out of stasis, it could have been that he gave the robot a project to complete that would take a long time, and only woke up to check on its project.


Installing Ubuntu 16.04 on RAID configure disk

i was trying to install ubuntu 16.04 on a disk configured with RAID 1, but the GRUB fails to install. can somebody please help


Switching baselayers as user zooms in to map in OpenLayers?

I have a  which overlays Open Street Map data on imagery for Pennsylvania. As a baselayer to the roads (and eventually other layers) I have two baselayers - Blue Marble NG and USGS EROS 1ft imagery. I would like to be able to combine these two layers into a single base map object that switches automatically as the user zooms in since it makes no sense to view the 1ft imagery for the whole state or the Blue Marble imagery when you are zoomed in.   Ideally I'd like to do this on the client side as I'm pulling the imagery from two different sites.


Let $A, B$ - sets such that $A \setminus B$ is infinite, $B$ - finite. Proof that $(A \setminus B) \sim A$


Automatically creating hyperlinks from bibliography to citation

I am usually using a combination of BibTeX and hyperref to create clickable citations, so a reader can easily jump from my text to the right place in my bibliography. Unfortunately there is no quick way to jump back: you have to manually find the place in the text where you paused your reading. Therefore I would like my reference list to contain hyperlinks to the location(s) in the text where I actually use the references.   Ideally this would work like it does in Wikipedia articles, e.g. , so there is a little clickable ^ if a citation is used once, and ^ a, b, ... if there are more 'calls' to a certain bibitem.   Is there a feature (or a package) that provides this functionality?   I can think of a way to implement this assuming all citations are used only once, but that's not the case in practice.


Why is the speed of light not 3 x $10^{8}$ m/s, or why not a round figure for the meter

This question is not about why the speed of light is not greater than 299,792,458 m/s. It's about why it's that exact value. This was a question from a book(I know homework questions are frowned upon here :P), and after almost 5 years, this has occurred back to me.  Is there any specific reason for that value? If it were, say, a scale at the International Bureau of Weights and Measures of exactly one meter length(as the cylinder of the kilogram), it would make sense. But I haven't heard of such a thing.


I need the Broadcom ethernet Driver installer for Dell inspiron 1521 ubuntu 14.04

Ethernet controller [0200]: Broadcom Corporation BCM4401-B0 100Base-TX [14e4:170c] (rev 02)


Where is "Show position of the mouse when the Control key is pressed"

I am using Ubuntu 13.04.  CTRL Key in VirtualBox is not working for me, that's because the "Show position of the mouse..." is hogging the CTRL key.  I don't see an option to disable this in the Mouse settings. Any idea what is going on? Any way to modify this behavior without the GUI?


Recently I read an interesting article about . I was puzzled because I thought before that  has definite meaning in thermodynamics: it tells about how fast atoms jiggle. Now if temperature can be negative, this means temperature has wider meaning...  I wonder if there is any deep physical meaning of temperature, not mathematical one.


What is the limit for salesforce Recyclebin?

suppose we will delete the records from recycle bin means where those records being(i mean which place those items saved). Is there any limit to get back those records(I mean Maximum how many days we can get those records).I used this query for get deleted records.  SELECT Id, Name FROM Account WHERE isdeleted = true ALL ROWS


An efficient way for generating smooth circle

I'm looking for creating smooth circle. OpenGL supports point, line, and triangle. To create other primitives like circle, we utilize the preceding shapes. In my case, I've utilized points as follows:   float radius(0.5f); for ( float angle(0); angle < glm::radians(360.0f); angle += glm::radians(0.5f) ){     Vertex vertices[] = { Vertex(glm::vec3( radius*cos(angle), radius*sin(angle), 0)) };     meshes.push_back(   new Mesh(vertices, sizeof(vertices)/sizeof(vertices[0]), 'P')   ); }   In rendering loop,  while( Window.isOpen() ){     Window.PollEvents();     Window.clear();     //================( Rendering )=========================     Shader.Use();      for ( int i(0); i < meshes.size(); ++i )         meshes[i]->draw();      //======================================================     Window.SwapBuffers(); }   The result is     Now to create smooth circle, basically I just increase the number of points. I don't like this approach since I need to create a lot of points for single shape. My question is is there an alternative yet efficient approach for this issue?


The system is running in low graphics mode error on dell inspiron.1525

How to fix “The system is running in low graphics mode” error on dell inspiron.1525?


Which number is bigger? $1.01^{101}$ or $2$? and how about $e^{\pi}$ or $\pi^e$?  Tried some algebraic manipulations to no end, so would love some suggestions or some different ways to approach those kind of problem


Is every finite category identifiable with a directed multigraph? (and vice versa?)

What seems implicit in  on youtube, is the claim that every directed multigraph (with loops) can be identified with a finite category and vice versa, if we consider the paths of the directed multigraph rather than just the edges (= 1-edge paths).  Is this true?  If it is true, why is there not more cross-fertilization between category theory and graph theory?       EDIT: The proposed identification:  The nodes are the objects of the finite category.  The identity morphisms are implicit (i.e. do not need to be depicted), but if they are to be depicted, then they are just a loop starting and ending at the corresponding vertex.  As stewbasic pointed out in the commented below, we need to stipulate that each edge in a path can only be traversed once. Each path should have a well-defined source and sink, so that the domain and codomain of our corresponding morphism are well-defined. We do not want to include arbitrary cycles.  Anyway, the morphisms are the paths of the directed multigraph, or the edges of the corresponding transitive closure of said multigraph (we want to interpret the arrows such that the associative rule holds, i.e. the composition of any two morphisms is again a morphism).      My guess would be that finite categories are uninteresting to the typical category theorist, not to mention 1-categories in general, and directed multigraphs are probably too pathological for the average graph theorist to care about.  Note that for this identification to work, we have to assume that the identity morphisms are implicit in the directed multigraph, but that really isn't a problem, since when composed with any other morphism they "disappear", at least in the sense that neglecting to draw the loops corresponding to the identity morphisms on the directed multigraph would not affect whether the transitive closure represents the corresponding finite category or not.      I assumed that nLab would have something to say about this, but no such luck:   From this page there is a clear correspondence between the transitive closure of a directed multigraph (or considering the paths of the multigraph instead of the edges) and posets, since we can define the nodes to be reflexive, antisymmetry follows from the multigraph being directed (from the nLab page it follows that symmetry for the relation implied by the multigraph holds if it is undirected), and transitivity follows from taking the transitive closure/considering paths instead of edges.  So if the above correspondence is correct, then in some sense finite categories, directed multigraphs, and posets all "coincide", essentially since they all describe the same type of relation.  I know that every monoid can be represented by a category with one object and the morphisms are just the elements of the monoid (the invertible elements being the isomorphisms).  EDIT: I think this question might be a duplicate, so I am voting to close this question. The original question did not come up in the suggestions or similar questions while writing this one, so thanks must go to Musa Al-hassy for finding and pointing out the similarity:


I want to calculate the Fourier Cofficient for the function defined by: $$f(\theta) =\frac {(\pi - \theta)^{2}}{4}$$ for $0 \leq\theta \leq 2\pi.$  but the definition for the Fourier Coefficient is from $-\pi$ to $\pi$ for the functions that is integrable on this interval.So, in my function shall I change  the boundaries in the definition of the Fourier Coeffient to be from 0 to $2\pi.$  But I do not think so because if I do this then I found that  $$\hat{f}(0) = \frac{\pi^{2}}{4}$$  But it is answered in the book as:$$\hat{f}(0) = \frac{\pi^{2}}{12}$$   Could anyone give me an advice?   thanks.


I have a Student Visa to Spain, after it expires can I leave to travel the rest of the Schengen area?

I am a citizen of the United States but next year I am going on exchange in Spain. My student visa will expire in the end of June but I want to travel around to visit friends and family I have in other countries within the Schengen Zone (ex. Denmark, Norway, Germany etc). I have tried reading other forums and questions with nearly the same type of question, but I still don't understand the answer. I know that under normal circumstances I can enter the Schengen Zone without a visa and travel within it for 90 days as a tourist. So after my visa expires, let's say I leave and go to Germany. Would that be okay or not? Because I didn't enter Spain/the Schengen Zone as a tourist until I leave Spain as a student. Is that logic correct?


I want to run the script temp-throttle () at startup and show a custom Plank icon.  The script will throttle CPU frequency at 79 celsius if run like so   sudo ./temp_throttle.sh 79   As it needs the temperature to be specified as above after cd in the path of the script, a second script is needed.  #!/bin/bash  cd "path-to-the-folder//temp-throttle-stable" terminator -e 'sudo ./temp_throttle.sh 79' --geometry=300x80 -p hold    I have called that temp-throttle and put it in $HOME/bin, as indicated .  In order to have some info on the situation, I have integrated the command in a terminal command and added -p hold that sets a terminal profile to keep terminal window open.  If I add that script to startup applications list, the icon used in Plank is that of the terminal.     I would like it to run at startup and show in Plank my custom "temp.png" icon    For that, I have created the file ~/.local/share/applications/temp-throttle.desktop with the following lines:  [Desktop Entry] Type=Application Name=temp-throttle Icon=temp Categories=System;Monitor; Exec=temp-throtle     Executing that directly (double-click) it shows the terminal icon in Plank.  I can make the dock use the custom "temp" icon by executing the .desktop file from the applications search&launch tool (e.g. Slingshot) or with the command gtk-launch temp-throttle (as suggested ).   After that, the custom Plank icon can of course be pinned to the dock (right-click, "Keep in Dock"). That creates the file /home/cipeos/.config/plank/dock1/launchers/temp-throttle.dockitem with the lines  [PlankDockItemPreferences] Launcher=file:///home/cipeos/.local/share/applications/temp-throttle.desktop   as suggested in the 's answer. He also seems to suggest in a comment that the important thing here is to have the exact same names for all files involved:  all my file are called temp-throttle.  The problem is how to run a .desktop file at startup: if I simply add the desktop file at startup it will not run at all. If I add the startup command  gtk-launch temp-throttle.desktop it will still use the terminator icon.    This question is close to this: , but different, as the answers under that (use a .desktop file) will not work if the command/script/desktop-file is run at startup.  It seems that at startup the final command/script is run without taking into account the Icon= line in the .desktop file, no matter the method used to run the .desktop launcher.   I have tested many answers under this question () but they will not keep the icon specified in the .desktop file if that is run at startup.     answer provides a solution for Unity, but it doesn't work as such for Plank.


Failed to mount early API file systems, freezing

Read-only file system error occurs while I am working on Ubuntu 18.04. Then I restarted my system, ran fsck /dev/sda2, and after that my system isn't working. Error is Failed to mount early API filesystem.


Do high export resolutions compromise image safety?

I specialize in macro photography and I've recently begun to export in 300-350dpi, as I find it does a better job of representing details (crucial to my work).   However the file size is small, eg. 1200px.   Am I compromising my image's safety? (given watermarks can be removed and files can be enlarged easily)


Feynman (Volume 1, 38-4) seems to explain the normal force of a floor acting on a table as quantum mechanical, arising from the Pauli Exclusion Principle and also, the Heisenberg Uncertainty Principle.  (see quote below).  This seems somewhat at odds with an explanation that I have heard many times, which is that the electrostatic repulsion of the opposite-facing electron shells generates the required force.  Presumably if Feynman considered electrostatics to contribute to this, he would have said so.  I am also surprised because I have heard of neutron star formation through electron degeneracy pressure, and had the impression that this pressure only appears manifest under extreme conditions. The wikipedia page on electron degeneracy pressure mentions that it plays a role in the bulk modulus compressibility of metals, and the description may imply that the strength of the contribution is undersood.  Is there any way to decompose the normal force contributions of the floor supporting a chair into contributions from electrostatics, uncertainty principle, and exclusion principle?  If so, what provides the primary contribution?  Feynman Quote, Volume 1 Chapter 38, Section 4 "So we now understand why we do not fall through the floor. As we walk, our shoes with their masses of atoms push against the floor with its mass of atoms. In order to squash the atoms closer together, the electrons would be confined to a smaller space and, by the uncertainty principle, their momenta would have to be higher on the average, and that means high energy; the resistance to atomic compression is a quantum-mechanical effect and not a classical effect. Classically, we would expect that if we were to draw all the electrons and protons closer together, the energy would be reduced still further, and the best arrangement of positive and negative charges in classical physics is all on top of each other. This was well known in classical physics and was a puzzle because of the existence of the atom. Of course, the early scientists invented some ways out of the trouble—but never mind, we have the right way out, now! (Maybe.) Incidentally, although we have no reason to understand it at the moment, in a situation where there are many electrons it turns out that they try to keep away from each other. If one electron is occupying a certain space, then another does not occupy the same space. More precisely, there are two spin cases, so that two can sit on top of each other, one spinning one way and one the other way. But after that we cannot put any more there. We have to put others in another place, and that is the real reason that matter has strength. If we could put all the electrons in the same place it would condense even more than it does. It is the fact that the electrons cannot all get on top of each other that makes tables and everything else solid. Obviously, in order to understand the properties of matter, we will have to use quantum mechanics and not be satisfied with classical mechanics."


From this paper:     Shouldn't $du$ be $dt$? And also how do you get from that line to the final result if $du$ is not $dt$?


First page number is missing in document

I want to add page number from 531-536 in my LaTeX IEEE conference template. But page number appearing from page 2 i.e. 532. Could anyone help me?  \thispagestyle{plain} \pagestyle{plain} \setcounter{page}{531}


The moon shone bright like a diamond in the sky. 2. The full moon is shining bright in the sky. Why not they are brightly? Are they correct?


Node.js is not accessible from external IPs on Ubuntu

I'm sure this is very noobish, so forgive me. I'm trying to run a node.js server on port 8080 of my ubuntu 10.04.  Here's the result of iptables -L on the server:  Chain INPUT (policy ACCEPT) target     prot opt source               destination           Chain FORWARD (policy ACCEPT) target     prot opt source               destination           Chain OUTPUT (policy ACCEPT) target     prot opt source               destination   And here's the result of nmap -p 8080 (edited the ip address because everything is or should be wide open)  nmap 173.203.xxx.xxx -p 8080 -A  Starting Nmap 5.00 ( http://nmap.org ) at 2011-05-19 22:52 PDT Interesting ports on xxx (173.203.xxx.xxx): PORT     STATE  SERVICE    VERSION 8080/tcp closed http-proxy   Why on earth is 8080 seen as closed? Adding this did not help:  iptables -A OUTPUT -p tcp  --dport 8080 -j ACCEPT iptables -A INPUT -p tcp  --dport 8080 -j ACCEPT   I'm really confused.  I'll add this, in case it helps, but I don't know   netstat -pan | grep 80 tcp        0      0 127.0.0.1:8080          0.0.0.0:*               LISTEN          16785/node       tcp        0      0 0.0.0.0:80              0.0.0.0:*               LISTEN      16471/apache2   I can access my regular website running off of port 80 on apache, but the node.js server is inaccessible from outside. Accessing it from the server itself works fine.  So my question is: how would I go about debugging this? Could there be something else than iptables blocking some ports? How do I find out what it is?  Any help much appreciated!


What to do when you spend several months working on an idea that fails in a masters thesis?

How shall a masters student deal with the complete failure to meet the expected results when working on a master's thesis?  For example, in the field of machine learning a masters student might spend 4-5 months  developing a method that turns out not be useful, not even being comparable to benchmark datasets.  Should the student quit it? Should you at least take a break from academia to avoid harming your career ?  Or should you work on a different idea and risk another few months which is also not guaranteed? Given the fact that the advisor is simply asking you to try new things


I've got the following loop (this is on a single page, not the index.php):  $top_meta_cat_args =     array(     'posts_per_page' => 9,     'post_type' => 'post',     'meta_key' => 'top-radio',     'meta_value' => 'top-yes',     'post_status' => 'publish',     'orderby' => 'date',     'order' => 'DESC' );   And it works perfectly. However, when I add code to take the user to the next page, nothing happens:  <a href="<?php echo get_next_posts_page_link();  ?>" class="btn-ar"> more articles   This adds to the current URL: &paged=3, but the content is still the same.  I've also tried removing the echo, but nothing happens. . But I am unsure how to use this with the associative array that I exampled above.  Any help would be great.


How to prove that $[(p \to q) \land (q \to r)] \to (p \to r)$ is a tautology without using the truth table?

I am looking for a way to prove that the statement, $[(p \to q) \land (q \to r)] \to (p \to r)$, is a tautology without the help of the truth table. By using only Laws and Theorems like De Morgan's Law, Domination Law, etc. Also, I can't use the rules of inference. Please help, thank you.


Please describe direct products in the category Rel.


Why does extended piston become stuck if air above it is powered?

To reproduce this problem make layout like this and then power the piston. Once the piston is extended, removing the power source will not retract it:    Since piston head block is transparent, I see no explanation for this. Also, even if it wasn't transparent, it still wouldn't power a piston. For example this doesn't power the piston:    But if I place redstone and THEN place the piston, it's powered:    It also remains powered no matter what, as long as there isn't a block update event:    I suppose this behavior can be used to make a block update detector, but in my case this sucks. I wanted such setup for automatic smooth stone generator (without any clocks):    But due to this bug, it won't work - the piston will be always extended.


Why it is necessary to override hashcode and equals method of key for Hashmap?

I created a HashMap having Student as key and String as value.  Now everywhere i have read It is necessary to override equals and hashcode method if using as a key for hashmap.  But I did not override it. And insert multiple key value pairs in hashmap. I am also able to fetch it back.  So why it is necessary?


I make gaming videos and recently installed Ubuntu and I haven't been able to find a good screen recorder for gaming. Are there any recommendations (preferably free ones) that can record in HD, use multiple audio sources (i.e. Headset and computer sound), and is in the Ubuntu Software Center? If it's not in the software center I still might get it, just preferably in the software center. I've already tried Kazam Screencaster and RecordMyDesktop, but they didn't work out for me. Thanks guys!


When I read asterisk source code, I found a code line like this:   #define ARRAY_LEN(a) (size_t) (sizeof(a) / sizeof(0[a]))    I often use a[0] or (*a), but they use (0[a]). Could you please help me explain more clearly about this?


I have used this racket (tennis racket) for 10 years./I have used this phrase for months and

I have been studying all day.    This is the normal (and most common) way to say that I have been studying all day and now I am tired etc.   However I often meet with sentences like:      I have studied all day.   The two sentences above are perfectly normal however the thing I am struggling with is that sometimes present perfect simple "version" is not acceptable and I don´t know why. For example "I have written letters all day" is the sentence which I was told was not correct - don´t really understand what makes that huge  difference compare to the sentence "I have studied all day".   I´ll give you another examples I did with my teacher:     I have used this racket (tennis racket) for 10 years.   ( Now I will start using a new type) - in her opinion this sounds ok and could be used     I have used this phrase for months and nobody has ever told me it   wasn't correct English.    Here,for some reason, my teacher definitely wouldn't use present perfect simple and would prefer to use present perfect continuous - again - I don´t see much difference between this sentence and the one above.   Would it be possible to explaing me, please, why sometimes one sentence is possible and another is not even though they are very similar to each other. I´d really like to learn to use this "strange" use of  present perfect simnple.  Thank you very much!


Suppose I come across old question with glaring syntax error or  - should I edit it thus throwing it to the top of the line, or leave it be?  Motivation to edit is in case someone come across it as result of a search, but as it's old and not relevant question anymore, it doesn't feel right to put it on top of the line again.  If we had the option to edit without bumping it would be ideal, but I guess such feature is not very realistic.  So, what's your opinion?


Does Filipino citizen with Slovenian residence need a UK transit visa?

I am a Filipino citizen living in Slovenia and I am a holder of a residence card as a family member of Slovenian citizen. With that card, I can travel with my Slovenian wife to the Canary Islands?  Our flight is from Ljubljana with transit in London Heathrow Airport, where we have to collect and recheck our luggage. Do we need a transit visa?


Proving that the connect sum of 3 copies of $\mathbb{C}P^2$ does not have a complex structure

Pardon my total lack of knowledge in complex geometry.  How would one go about proving that the connect sum of 3 copies of $\mathbb{C}P^2$ does not admit a complex structure?  Note that this manifold does admit an almost complex structure.


SSH alternative for a long range/high latency connection

I'm about to set-up a raspberrypi in a remote location (300+km to me). It will connect via GSM since there's no landline on 3G/4G. I need a way to "ssh" inside the pi to manage some stuff. Since GSM has no port forwarding my idea was to use  to tunnel the shell connection.   The only problem is that SSH is too heavy to run on a 600+ms connection. Mosh seems good and robust but I need to set a static key and port and I don't know if it's possible.   Telnet is also an option since ngrok encrypts the tunnels. Any alternative? I also need to upload/download some small files (x/zmodem?)


Is there any definitive I2C pin-out guidance out there? Not looking for a "STANDARD"

EDIT: This has been repeated several times, so putting it on top: Yes, it is well known that there is no "standard" for I2C inter-device connectors, but surely this community can formulate a list of "guidance" points for making such interconnects, based on signal behavior, noise minimization, and mitigation of risk due to wrong connections.    NXP defined the  without specifying a pin-out for I2C connectors, is my understanding. The only guidance from NXP seems to be a mention of placing a Ground and / or Vss between SDA and SCL if Vss / Gnd are carried across the interconnect.  Purchases of various I2C modules has left me with a variety of I2C pin-outs, and a bit of a task keeping track of the various little ribbon-cable-switching shims I've had to make for them.   e.g.    Mono OLED module: SCL, SDA, GND, 5V (obviously not ideal, since clock and data are next to each other. Sensor Shield for Arduino: SDA, SCL, GND, 5V (again not ideal, plus switched SCL/SDA) Color LCD module: SCL, GND, 5V, SDA (Yay!) No-name I2C repeater: SCL, 5V, GND, SDA (ouch, they switched power pins! Nearly let the magic smoke out.)   So my question is this: Is there a definitive / authoritative guideline for the I2C 4-pin connector pin-out sequence to use, where both Vss and GND are to be carried from host to device?  Failing this, is there any directory, however incomplete, of I2C modules / devices listing the pin-out each has adopted?  Clarification: Looking for guidelines such as "put Vss closer to SCL because..." rather than a defined standard which clearly does not exist.


Intuitively, why does it make sense for the rationals to be countable?

I understand how to prove it... but without any kind of rigorous mathematical proof, how could it be explained to a layman who understands countable sets that $\mathbb{Q}$ is in fact countable? I have seen from other posts on this site vague ideas, but none are as fulfilling as I would have hoped.   e.g. My closest idea was that if a rational number can be expressed as $\frac{p_i}{q_i}$, then do:   Set $q_j=j$. For $i\in \mathbb{N}$,  then do $\frac{\sum p_i}{q_j}$.  Set $q_j=j+1$ do $\frac{\sum p_i}{q_{j+1}}$   etc .... although i'm not sure this quite works?  I think the above can be shown with examples to a layman quite easily, are there any other (simpler) ideas?


EDITOR: subsidiary program 'emacs -nw' not found

I have set up  $ echo $EDITOR emacs -nw   I was wondering why it is not found here, and how I can solve the problem? Thanks.  $ sdiff -o sdiff.out f1 f2 1 2 3                                 | 2 3 4 %e1 sdiff: subsidiary program 'emacs -nw' not found   I don't know why an option in $EDITOR is a problem, and where it is required in sdiff source code? I guess it is here   prog = getenv ("EDITOR"); if (prog)   editor_program = prog;   and here   execvp (editor_program, (char **) argv);   or  and . I am not sure what the program is doing.  For comparison, the following works perfectly fine:  $ eval "$EDITOR"


Let $C$ be an abelian category. Assuming that $\hom_C(A,B)$ has an abelian group structure, prove that the zero map $0_{AB}:A\to B$ is the neutral element of this group.   I know that the group operation can be defined as $f+g:=\nabla_B\circ(f\oplus g)\circ \Delta_A$ for every $f, g\in\hom_C(A, B)$, where $\oplus$ is the biproduct, $\Delta_X:X\to X\oplus X$ is the diagonal map and $\nabla_X:X\oplus X\to X$ is the codiagonal map.   Defining $\varphi:=(f\oplus 0_{AB})\circ \Delta_A$, I've shown that $\pi_1\circ\varphi=f$ and that $\pi_2\circ\varphi=0_{AB}$ (where $\pi_1$, $\pi_2$ are the natural projections), which intuitively means that $f+0_{AB}=\nabla_B\circ \varphi=f$, but I don't know how to formalize this.  How do I show this formaly?


How do you stop all interactive prompts from apt-get when installing or upgrading packages?  I'm trying to write a non-interactive script to install packages on servers, whenever an upgrade requires installing a new kernel, apt-get always ignores the -y option and prompts me on what option to take to update grub.lst. I always want to install the package maintainer's version. How do I disable this prompt?


Efficient way of finding the first occurrance of a number in a 2D scipy array?

I am trying to find the occurance of certain number in a 2D scipy array. The returned value should be the indices of first and second slice like (x,y).  What could be an absolutely efficient way of doing it?  Thanks a lot


Will the Windows 10 Free Upgrade stay in the Professional channel?

When the free Windows 10 upgrade comes out, will you get the Pro version or Home version if you have Windows 8.1 Pro or Windows 7 Professional or Ultimate?


So I am trying to extract an output similar to   x=($discover nginx --human=nood)   which gives me an output like      i-03099   nginx   IP  noodlefish      pip b4b966d280546c6b070f5f952c281d3294308048   Further I want to extract the pip column in another variable.  When I do  echo "$x" | cut -f6   I get my desired output, but when I try.  y= "$x" | cut -f6    I get a blank output.   Please can you explain me why is this happening and how can I get the result I want. Thank you in advance.


Confidence interval for reciprocal proportion ($\frac{1}{p}$)

Is there a "nice" closed-from expression for the confidence interval (CI) of the reciprocal binomial proportion, $\frac{1}{p}$?  I'm actually looking for a CI for $\frac{N}{p}$, which will be a simple task once a CI for $\frac{1}{p}$ is in hand.


How do I remove the default dock completely (even from Activities overview) on Ubuntu with GNOME?

This huge dock appears when I press the Windows key:   I already have plank installed, I just want others dock to be completely removed, I already run a command to remove the default dock, I don't know what the heck is this appearing here, this is very frustrating.


My weapon wheel is full and I bought new weapon how do i equip it?I tried to look in inventory but there is just glasses hats and masks!


If possible, can someone help me to animated this figure with Tikz in Beamer?   I updated starting by   1 : ( Yamada-watanab ) 2: (Existence faible) 3: (unicite trajectorielle) 4: Tow edges frome  (Existence faible)  (unicite trajectorielle) 5: one Edge from  ( Yamada-watanab ) To (Existence Forte) 6: one Edge from (Existence Forte) to (Defintion) (left one ) 7: one Edge from (defintion) (left one) To (Existence faible) 8: One Edge from (unicité trajectorielle) To (Defintion) ( right one) 8: One Edge from (Defintion) ( right one) To (unicité en loi) 9: (unicité en loi) 10: (Engelbert-Cherny)  11: Tow Edge from (Existence Forte) and (Unicité en loi) To (Engelbert-Cherny) 12: One Edge from (Engelbert-Cherny) To (Unicté trajectorielle)   I tries to use package animated but failed:  \documentclass[leqno,mathserif]{beamer}   \usepackage{graphics,bm} \usetheme{Luebeck}  \setbeamercovered{transparent} \usepackage[utf8]{inputenc}   \usepackage[T1]{fontenc} \usepackage[english,french]{babel} \usepackage{tikz} \usetikzlibrary{positioning}  \usetikzlibrary{matrix} \begin{document}      \begin{frame}         \begin{figure}             \begin{tikzpicture}                 \matrix (magic) [matrix of nodes,ampersand replacement=\&, column sep=7mm, row sep=5mm]{                     \node (se) [draw,shape=rectangle] {Existence Forte}; \&                     \node (yw) [draw,shape=circle] {Yamada-watanab}; \&                     \node (ul) [draw,shape=rectangle] {Unicité en Loi}; \\                     \node (d1) [draw,shape=circle] {Définition}; \&                      \&                        \node (d2) [draw, shape=circle] {Définition}; \\                     \node (we) [draw, shape=rectangle] {Existence Faible}; \&                     \node (ec) [draw, shape=circle] {Engelbert-Cherny}; \&                      \node (pu) [draw, shape=rectangle] {Unicité Trajectorielle}; \\                 };                 \draw[->, thick] (se) -- (d1); \draw[->, thick] (d1) -- (we);                 \draw[->, thick] (we) -- (yw); \draw[->, thick] (yw) -- (se);                 \draw[->, thick] (se) -- (ec); \draw[->, thick] (ul) -- (ec);                 \draw[->, thick] (ec) -- (pu); \draw[->, thick] (pu) -- (yw);                 \draw[->, thick] (pu) -- (d2); \draw[->, thick] (d2) -- (ul);             \end{tikzpicture}         \end{figure}     \end{frame} \end{document}


Since Cyclotomic polynomials are irreducible over $\mathbb{Q}$, $\phi_n(x)$, $\phi_m(x)$ are coprime as polynomials in $\mathbb{Z}[x]$.   Working over $\mathbb{Q}$, $(\phi_n(x)$, $\phi_m(x))=(1)$. This implies that $(\phi_n(x), \phi_m(x))=(c)$ for some $c \in \mathbb{N}$ when this ideal is considered in $\mathbb{Z}[X]$. Can this $c$ be evaluated as a function of $n,m$? What can be said about $f(x) = gcd(\phi_n(x),\phi_m(x))$, when the polynomials are considered as scalars, i.e. evaluated at some $x$? $\forall x: f(x) | c$ from question 1, but can something stronger be said? More concretely, what is the image of $f$?   EDIT:  This  by Apostol, provided in the comments to Greg's answer, gives a pretty good answer, which Greg guessed.   It basically calculates the resultant of 2 cyclotomic polynomials, which gives a number that is divisible by the optimal constant $c=(\phi_n(x), \phi_m(x))$, and it is either 1 (when $\frac{n}{m}$ is not a prime power) or a power of a prime ($p^{\phi(m)}$ when $\frac{n}{m}$ is a power of $p$).  When it is $1$ (the common case), we have a full answer for both questions. When it is a prime power, we only have an upper bound for the multiplicity ($\phi(m)$, when $m|n$).  This  gives some weaker result but it is simpler.


Java downcast on Custom Class extending Date - runtime error

I have a class like this:  public class DateS extends Date {     public DateS yesterday(){         Calendar cal = Calendar.getInstance();         cal.setTime(this);         cal.add(Calendar.DAY_OF_YEAR, -1);         return (DateS) cal.getTime();     } }   It can be successfully built. At runtime, when I call date.yesterday(), a Cannot cast 'java.util.Date' to 'myproject.package.DateS' are throwed.  I need to know why and what can I do to fix this.


My problem is to find the sum of the series $$ S = 1+\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+\frac{1}{6}+\frac{1}{8}+\frac{1}{9}+\frac{1}{12}+\cdots $$ where the terms are the reciprocals of the positive integers whose only prime factors are $2$s and $3$s.   I can see that every term in $S$ is of the form $\dfrac{1}{2^m3^n}$ where $m,n\geq 0$. I can also see that each term only occurs once, but I'm not really sure how to use this information effectively. Any ideas (apparently geometric series was a hint)?


Which is correct?     Everyone were convinced that he would go to the game.   Everyone was convinced that he would go to the game.   I think it's "was", because "everyone" is singular, but I just wanted to check.


Does anyone know a closed-form expression for a bijection between $\mathbb{N}^k$ and $\mathbb{N}$?

I want to publish an article and one of its results is a simple closed-form expression for a natural bijection between $\mathbb{N}^k$ and $\mathbb{N}$. I wish to know whether it is already known.


Should black holes be considered two-dimensional or three-dimensional?

Should a black hole be considered two-dimensional or three-dimensional?  It means that a black hole doesn't occupy space, but interacts with it. Or it actually occupies space, and still interacts with it?


How to upload a file of size 2GB from Apex? Is there any sobject that I can make use of?


Find word in string with random digits before and after

I tried several solutions from the internet an worked myself through some tutorials but I am not able to make it work. I try to match a word in a string with random letters, numbers or dots before and/or after.  eg.  Meeting.Room  MeetingRoom21  Room  Meeting2Room  Meeting.room  12MeetingRoom110.MeetingRoom  I try to match the word "Room" but it should not be case sensitive.  The last pattern I tried was this: \b()(\wRoom\w)\b \ig  But I use regex not that much and I struggle to solve something after three months.  I hope someone can help me.   public bool Regex_check_for_match(string input, string pattern)  {      bool ismatch = Regex.IsMatch(input, pattern);      return ismatch;  }


How can I produce the correct unicode character for í for a name in the bbl file as reference ?  I wrote it like this Mac{\'{i}}as but error still shows.


Young Adult novel - Brother and Sister go back in time and meet Cuchulain

This is probably an easy one, but I can't think of the right combination of keywords. I read it as a hardback around the late 1980s to the early 1990s. It involved a brother and sister who somehow wound up back in early ages of Celtic Ireland. They meet a young man who turns out to be , although I want to say that he used a different name, so it took the children a while to catch on. It was definitely a fantastic take on it, as I remember Cuchulain using Gáe Bulg, his magic spear. Specifically, there was something involving chasms belching poisonous gasses, but he could breath with his mouth by the spear (which does not seem to be among the legendary qualities of that weapon).  I vaguely remember that the children first encounter Cuchulain by a body of water, I think as he was bathing. When the children are returned home, they return with a carved comb of bone or ivory. I remember they also came home with a case of lice, which required boiling the comb. Things that stick with you... There might have been a sequel, but I don't remember any details if so.  I think (and this is very tenuous) that the cover had the brother and sister stepping out of a forest, hand in hand, with Cuchulain down by the water's edge, as per that first meeting.


Evaluate $\int \frac{1}{\sin x+\sec x}\,dx $

Evaluate $$\int \frac{1}{\sin x+\sec x}\,dx $$ Expressing $\sin x$ and $\cos x$ in terms of $\tan\frac{x}{2}$ i.e. putting $\sin x=\dfrac{2t}{1+t^2}$, $\cos x=\dfrac{1-t^2}{1+t^2}$ and hence $dx=\dfrac{2\,dt}{1+t^2}$ $$\int \frac{1-t^2}{1+t-t^3}\,dt $$


I have downloaded PyCharm and unzipped using unzip command. By using help from the internet I did everything to install it, but the ./configure command shows me an error: bash: ./configure: No such file or directory


Let $u,v\in W^{1,p}(\Omega)$ with $1<p<\infty$ and $\Omega$ be a bounded smooth domain in $\mathbb{R}^N$. Suppose, we have $$\int_{\Omega}|\nabla u|^{p-2}\nabla u\nabla v\,dx=\left(\int_{\Omega}|\nabla u|^p\,dx\right)^\frac{p-1}{p}\left(\int_{\Omega}|\nabla v|^p\,dx\right)^\frac{1}{p} $$ Suppose the equality $$ \int_{\Omega}|\nabla u|^p\,dx=\int_{\Omega}|\nabla v|^p\,dx $$ holds. Then can we say that $u=v$ in $\Omega$? I tried in the following way: Since the first given equality, which is the equality in Holder's inequality holds, and by the second given equality holds, we have $|\nabla u|=|\nabla v|$ in $\Omega$. Then I am unable to proceed. Can someone please help to give an argument?


calculate the ACF of $y_{t}=x_{t}x_{t-1}$

I am currently working on this problem that asked me to calculate the ACF of  $Y_{t}=x_{t}x_{t-1}, x \sim IID{\left\lbrace0, \sigma^{2}\right\rbrace}$  what I've done so far is, I have proved that $E[y_{t}]=0$, so I'll take it as given in the following calculation.  here I am calculating the ACF of $y_{t}$: $$ \begin{aligned} COV(y_{t+h}, y_{t}) &= E[(y_{t+h} - E[y_{t+h}])(y_{t} - E[y_{t})]\\ &= E[y_{t+h}y_{t}]\\ &= E[x_{t+h}x_{t+h-1}x_{t}x_{t-1}]\\ \end{aligned} $$  given $x \sim IID{\left\lbrace0, \sigma^{2}\right\rbrace}$, therefore we can separate the expectation above into: $$ E[x_{t+h}x_{t+h-1}x_{t}x_{t-1}] = E[x_{t+h}]E[x_{t+h-1}]E[x_{t}]E[x_{t-1}] \qquad(1) $$  if $h \neq 0$, then $(1)=0$ because we have $E[x_{t}]=0$  if $h = 0$, then (1) is  $$ E[x_{t}]E[x_{t-1}]E[x_{t}]E[x_{t-1}] = 0 $$   which we could then conclude that ACF of $y_{t}$ is 0.  it all looks correct me but the solution gives different answer when $h =0$, could anyone spot what I've done wrong?  thanks!   EDIT:  given the comments, there's one thing I've done wrong above; when $h = 0$,  the independence cannot be applied because two or more indices are the same. this implies dependence (I think)  I therefore did,   $$ \begin{aligned} E[x_{t+h}x_{t+h-1}x_{t}x_{t-1}] &= E[x_{t}x_{t-1}x_{t}x_{t-1}]\\ &= E[x_{t}^{2}x_{t-1}^{2}] \qquad (2) \end{aligned} $$   I am stuck again because I don't know how to prove  $$ (2) = E[x_{t}^{2}]E[x_{t-1}^{2}]\qquad (3) $$   one more hint, I could solve it!


Finding out what App causes unwanted new tabs in firefox on Android

Recently some app started opening new firefox tabs with the adress 'livemobilesearch.com'. I uninstalled the most recentently installed apps, but the problem still persists. I assume the pages get opened when I unlock my phone from standby, because sometimes after I unlock the phone the screen flashes for a second and if I open the firefox after that, a new tab with said webpage is open. I already deleted the 'cache' and 'data' of the firefox app but nothing changed. Also I tried an anti virus and malware software called "Malwarebytes Security: Virus Cleaner, Anti-Malware", but it didn't find anything. I have two ideas / questions to find out what causes this problem:   Does the firefox app have a logfile that tracks from where pages are openend? Is there a way to see a list of receivers that are 'subscribed' to the SCREEN_ON Event?   If anyone has another idea to how to fix my problem I'd be glad to hear it.  Thanks in advance.  EDIT: I've read and followed the instructions of the related articles from the comments. dumpsys activity activities shows the following:  * TaskRecord{3bf05cb #1075 A=com.android.chrome U=0 StackId=1 sz=1}   userId=0 effectiveUid=u0a103 mCallingUid=u0a103 mUserSetupComplete=true mCallingPackage=com.android.chrome   affinity=com.android.chrome   intent={act=android.intent.action.VIEW dat=https://livemobilesearch.com/?utm_campaign=dist&utm_source=foobar flg=0x14002000 pkg=com.android.chrome cmp=com.android.chrome/org.chromium.chrome.browser.ChromeTabbedActivity}   realActivity=com.android.chrome/org.chromium.chrome.browser.ChromeTabbedActivity  ....  * Hist #0: ActivityRecord{bbeee47 u0 com.android.chrome/org.chromium.chrome.browser.ChromeTabbedActivity t1075}       packageName=com.android.chrome processName=com.android.chrome       launchedFromUid=10103 launchedFromPackage=com.android.chrome userId=0       app=ProcessRecord{408bf79 18941:com.android.chrome/u0a103}       Intent { act=android.intent.action.VIEW dat=https://livemobilesearch.com/?utm_campaign=dist&utm_source=foobar flg=0x14002000 pkg=com.android.chrome cmp=com.android.chrome/org.chromium.chrome.browser.ChromeTabbedActivity (has extras) }       frontOfTask=true task=TaskRecord{3bf05cb #1075 A=com.android.chrome U=0 StackId=1 sz=1}       taskAffinity=com.android.chrome       realActivity=com.android.chrome/org.chromium.chrome.browser.ChromeTabbedActivity   The way I understand the output is, that the tabs were opened from chrome. I've disabled chrome for now, as I can't uninstall it.   EDIT 2:  The problem still persits. Even though I followed the steps in the similar thread in the comments, the unwanted page still gets opened. I can't uninstall Chrome since it is a system app (I have a sony xperia x compact on Android 8.0.0).   After I disabled Chrome the unwanted page is still opened. It now states in the dumpsys: "launchedFromPackage=org.mozilla.firefox". It would appear, that the solution form the comments is in my case not working.  Any advice would be much apreciated.


Should linked questions be removed from related questions?

Currently the same question can be listed in both as linked and as related. This seems inefficient and confusing.  Example:


I was playing with an old point and shoot camera and I made this close-up photo of a pepper:     I took many photos and it seems I can’t get a sharp image across the whole object. Can I make this better with settings? Is 8 megapixels not enough?  Or is my point-and-shoot camera really that bad that the only chance of improving this image is with a new camera body and a better lens (macro lens)? If so, what cheaper options do I have (beginner lens + extension tube)?  My settings: f7.1  1/4 sec  ISO-80  Camera model: Canon PowerShot S5 IS Focal length: 6mm  I took another photo:   The front side seems sharp enough but how can I make the left side that is further away from the camera just as sharp? f/8 1/5 sec ISO-80


What happens when $\lvert\omega\rvert =1$?

If this is a duplicate in any way, I'm very sorry.  I'm brushing up on some Complex Analysis with Special Functions in mind. Here's a problem I'm stuck on.     Evaluate the integral $$I=\frac{1}{2\pi i}\oint_{\lvert z\rvert=1}f(z)\, dz$$ over the counterclockwise oriented unit circle centred at $0$, where $$f(z)=\frac{2z}{z^2+\omega^2}$$ for $\omega\in\Bbb{C}$.   I'm pretty sure I know what happens when $\lvert \omega\rvert\neq 1$; it's simple: break it down into the two obvious cases. But what happens when $\lvert\omega\rvert =1$?    What I've done so far is let $z=\gamma (t)=e^{it}$ for $t\in [0, 2\pi ]$ and arrived at $$\frac{1}{\pi}\int_0^{2\pi}{\frac{dt}{1+\left(\frac{\omega}{e^{it}}\right)^2}},$$ hoping to use the derivative of $\operatorname{arctan}$, which isn't going to work, of course.  I'd like a few hints please :)  A hunch: I'm tempted to say that the integral does not exist for $\lvert\omega\rvert=1$ but I've no idea why.


Suppose I have a paper with the following text:     Roses are red, violets are blue, sugar is sweet, and so are you [3],[4].   As one can see, the author got the information from two other references. If I want to add this information in my thesis, do I also have to reference [3] and [4] or can I just reference this particular paper, I got the information from?


Would LAMP stack break my daily use Ubuntu 16.04?

If I install LAMP in my Ubuntu 16.04 Desktop and make it as my web development environment, would it break my Ubuntu 16.04 desktop?


Please display additional user information on the Android app user profile

When I'm viewing a user profile, it's more often than not to gauge this user within the community. How long they have been a member, how active they have been, when was their last activity and of course, what content are they contributing. This is accentuated when the user in question is a relatively new user. I would want to know this in order to make my response or comment more informative and to not be too harsh on inexperienced users.  One good measure I use to identify a new user is their join date. I would like to request that the "member for" field be added to the profile page for users on the mobile application just as it is when viewing the desktop version.  The "last seen" field would also be useful. It's useful to me on the desktop version to know more or less when/if to expect a response from a user after leaving them a comment/answer. It would useful on the mobile version for the same reasons.    I just realized that this information is available on the mobile version of the webiste. If it was decided that this information is important enough to also appear on the mobile web version, why not include it on the native mobile applications?


Windows key not "waiting" for another key

So my Windows 8.1 recently updated, and I don't know if this is the cause of my problem, but it started after the update.  The problem: when I press Windows key it doesn't wait for me to release it before showing the Start Screen, so whenever I want to use it together with another key on a shortcut, it always shows the Start Screen before anything, and I don't want that.  Example: I want to minimize everything and I press Windows + D, but it shows the start screen. I'm still holding down the Windows key when I press D, I'm doing the correct way, but the system shows me the start screen instead of the Desktop.  Is there a way to fix that? Maybe on settings somewhere there's an option for that?  PS.: Sorry if this question already exists, I tried looking for it and didn't find anything.


Find the number of integral solutions of $2x + y + z = 20$?

Find the number of integral solutions of $2x + y + z = 20$ where $x,y,z \geq 0$ ?  Can I solve it by using stars and bars method of combinatorics?


Show that $\text{trace}(A^TA) \ge 0$ and $\text{trace}(A^TA)$ if and only if $A = O$

Problem Show that $\text{trace}(A^TA) \ge 0$ and $\text{trace}(A^TA)=0$ if and only if $A = O$ when $A \in \mathbb{R}^{n \times n}, n \in \mathbb{N}$. Symbol $O$ denotes zero matrix. Attempt to show I think I know intuitively this is right but how to prove this? I could show some example but unfortunately, this won't exactly prove anything. The problem is how to approach this proof?


Disable Narrator shortcut key in Windows

I've install Windows 8 on a BootCamp macbook air The problem is that the command key located differently from the winkey in a normal keyboard, therefor, I keep clicking Winkey+Enter which starts the narrator (which is really annoying!)  Is there a way to disable this shortcut?


Who is the oldest character in LotR trilogy?

Who is the oldest character in the trilogy, what is his role, race and powers?


What is the concept of erasure in generics in Java?


I have been running Ubuntu for about a year, now I would like to switch to kubuntu. Is it possible that I can port all the configuration data from the home folder of Ubuntu to kubuntu? (Without causing some serious trouble) If I copy all them contents of the home folder (Including the hidden files and folders) will I be able to get the same application configurations ? I know that copying the Thunderbird folder copies the emails on the newer installation, will it work to other applications?


Can a partially homomorphic encryption scheme be made CCA1 Secure? like paillier ? what is the highest security for any PHE?


I am trying to download Ubuntu to use in VirtualBox but every time I try to download it, it fails?

I have tried downloading Ubuntu many times just to have the download fail about halfway through. Any help?


How can centripetal acceleration change the speed?

In the circular motion of a particle, it has two acceleration components, first, the tangential one which is responsible for increment (positive or negative) in speed and is $$ \frac{d \omega}{dt} \times r$$ and the other is centripetal acceleration and is responsible for the change in direction and is $$\omega \times \frac{dr}{dt}$$. Now imagine that you are rotating a stone with a string tied to it and then you slowly start to increase the centripetal acceleration which means that you start pulling the string with your other hand then according to the equation of circular motion kinematics, the magnitude of the velocity shouldn't be affected but now according to a new law that I studied which is the conservation of angular momentum, the object must increase its magnitude of velocity in order to conserve angular momentum and I don't get that, aren't the laws contradicting themselves and how does increase the central force even results in an increment of speed ?


Getting record type id by developer name without making query

We have below describe call to get the record type id by name.  Id recordTypeId = Schema.SObjectType.Case.getRecordTypeInfosByName().get('RECORD_TYPE_NAME_NOT_DEVELOPER_NAME').getRecordTypeId();   This gives the id of the record but this logic is based on label of the record type instead of developer name. That means if we change the Label of record type then any code using such mechanism will break.  I know we can make a query to get the record type id by developer name but that will cost me a SOQL which I don't want to.  Is there any describe call to get the record type id by developer name without making the SOQL?


Every time I think I have the curve modifier mastered, it throws me a another curve ball (no pun intended).  Why in  can I not get the lights to follow the spiral curve? When the modifier is activated, the lights are stretched and distorted along the curve.  I created the curve by converting it from a mesh (string of verts). Why does it not display like a normal Bezier? Is that related to my problem?  I am following all the "rules" that I am aware of, as detailed here: . The curve seems to run in the correct direction. The origin point is at the first point of the curve. The curve modifier on the lights is set to -Y which is the local orientation of the curve's direction.  What am I missing?


How to Move Bottom Unity Launcher in Ubuntu 14.04.01 LTS

I want move unity launcher to bottom. I tried   sudo add-apt-repository ppa:paullo612/unityshell-rotated  sudo apt-get update  sudo apt-get install unityshell-rotated libnux-1.0-0 compizconfig-settings-manager   Console say "unityshell-rotated" and "libnux-1.0-0" packate not found.  What should i do ?  EDIT:  I want be like this


.NET How to check if path is a file and not a directory?

I have a path and I need to determine if it is a directory or file.    Is this the best way to determine if the path is a file?  string file = @"C:\Test\foo.txt";  bool isFile = !System.IO.Directory.Exists(file) &&                           System.IO.File.Exists(file);   For a directory I would reverse the logic.  string directory = @"C:\Test";  bool isDirectory = System.IO.Directory.Exists(directory) &&                              !System.IO.File.Exists(directory);   If both don't exists that then I won't go do either branch.  So assume they both do exists.


How to restore default cmd behaviour in Windows 10?

In Windows 10, when I used to type cmd in Run. The PowerShell was used to open inside black cmd like window.   My friend has somehow made cmd open cmd.exe, which was default in the previous version of Windows, but not Windows 10. Now he doesn't remember how he did.   How do I reset to open PowerShell inside cmd?


How can I install Windows 10 alongside Ubuntu 20.04 LTS?

Now I am using Ubuntu 20.04, but now I want to install Windows 10 alongside my 20.04 LTS. I am trying to make a partition but I can't make it.  Can you tell me the solution? When I try to install Windows, it shows the disk is a NTFS file, Windows can not install on this drive. What is the solution?


why am i getting a ConcurrentModificationException while using iterator?

I am using the following code to loop through an arraylist and then the method setAllDancersRest() will edit the arraylist that I am looping through. I tried to fix this issue by using an iterator but I still get the exception.      for (Iterator<Dance> iterator = allDances.iterator(); iterator.hasNext();) {         Dance dance = iterator.next();         if(generated.size()<= 0) {             generated.add(dance);         }         else if(allDancersReady(dance, gap)) {             generated.add(dance);             for(Dancer dancer: dance.getPerformers()) {                 dancer.setPerformed();             }             setAllDancersRest(dance);         }     }   my error:      Exception in thread "main" java.util.ConcurrentModificationException at java.util.ArrayList$Itr.checkForComodification(Unknown Source) at java.util.ArrayList$Itr.next(Unknown Source) at EliminationGenerator.generateOrder(EliminationGenerator.java:23) at EliminationGenerator.generateOrder(EliminationGenerator.java:1) at Model.generateRunningOrder(Model.java:98) at TUI.getAndProcessUserOption(TUI.java:70) at TUI.<init>(TUI.java:27) at testMain.main(testMain.java:11)   Body of allDancersReady():  private boolean allDancersReady(Dance dance, int givenGap) {     for(Dancer dancer: dance.getPerformers()) {         dancer.setGap(givenGap);         if(!dancer.isReady()) {             return false;         }     }     return true; }   body of setAllDancersRest():  private void setAllDancersRest(Dance dance) {     allDances.remove(dance);     Set<Dancer> dancers = new HashSet<Dancer>();     for(Dance tempo: allDances) {         dancers.addAll(tempo.getPerformers());     }     dancers.removeAll(dance.getPerformers());     for(Dancer dancertemp: dancers) {         dancertemp.notPerformed();     }  }


Dragging and dropping a tag into the Edit Favorite Tags textbox

It may be wrong on my behalf to assume the following behavior as correct but:  I'd would expect to be able to drag and drop (instead of typing) any tag into the favorites tags textbox.  Dragging and dropping any tag into the TextBox while editing the favorite tags section should fill in the textbox with the text from the tag.    So for example, if I grab a  and drop it in the Textbox I would want the textbox to display C# instead of   http://stackoverflow.com/questions/tagged/c%23


Number of real or purely imaginary solution

What are the number of real or purely imaginary solution of the equation , $$z^3 +iz -1=0$$   In this I tried to substitute $z=x+iy$ and solve it, but it is getting too long, and the answer is also not coming


I am having difficulty understanding time at the most fundamental level, especially I am wondering whether there exists an indivisible unit of time (i.e. whether time at some fundamental level is discrete). If the question is non-nonsensical, please help me with how to think about time.  Research for and against this notion are very welcome.


While I was executing a C program in terminal I wrote:  gcc -o demo demo.c ./demo   Actually my doubt is why we write ./ before demo and what does it mean?


Finding domain/range of a specific shader node input/output, inside the Blender UI?

Is there anywhere within the Blender UI that displays the dimensionality & bounding sets (e.g., all floats, floats in [0,1], floats in [0,255], etc) of arbitrary shader node inputs & outputs?  I consistently find myself digging through stackexchange/the Blender docs/experimenting with less-than-equal-to to try to figure out what I need to divide by to normalize shader nodes' input/output values to within a specific range, or to center them at 0, etc. This seems like functionality that Blender's very rich UI might already have built into it, though, so I am wondering if I am just overlooking it somewhere.  As an example, I can do something like this, varying the threshold between 0, 0.5, and 1, and observing that in rendered view my sphere switches from all black to mixed black/white to all white, to convince myself that Blender's (Perlin) Noise Texture's Fac output naturally outputs floats in [0,1]:    But it seems odd that I should have to experiment, or search through docs or stackexchanges, to discover something like this. Is this information maybe already neatly displayed somewhere inside the Blender UI, and I just don't know where to look?


What are the mathematics I need to learn, before I start research in data mining

I usually use text mining, graph mining, Information retrieval, and natural lanuage processing. Also i will use the fundamental concepts of data mining like classification, association and clustering. Please suggest me solution and study material( text books).


Start C# application on Windows Startup and keep focus

I'm developing a simple program that reads a card or a barcode and logs that on a database. Before, I developed the same application in Visual Basic and it was working great, but due to a lot of changes on our servers, we decided to develop this app in C#.  I can get my application to start with Windows putting its shortcut on 'startup' of the start menu but the problem is that its not getting focus so that the cards and barcodes can be read and that way my program is simply useless. The machines we use are running Windows XP and Windows 7.  How is the best way to start my application on Windows Startup and keep the focus in it?


How do I hide my accounts on a specific Stack Exchange site?

Can I hide my accounts that I already participate in, for a specific site?  For example, I'm in one where I don't want to make my accounts visible for others:    Or is this not possible?


Science Fiction book about alien species destroying earth with asteroids

In the 70s I read this SF book about an alien species destroying earth using asteroids from the astroid belt between Mars and Jupiter. It was done by 2 physicists and was presenting the case that earth should be very cautious about broadcasting itself into Space. That species would be very xenophobic and not tolerate competition from another technologically advanced species. Any help would be appreciated in locating the title of this book.


Add/Edit multiple Records on custom VF page

Is it possible to add or edit multiple records on a custom VF page? For the example below, if lineItemList return fewer than 10 records, I would like to render blank inputfields for insert of new records. The way I have it set now, it will only render as many inputfields as existing records. As always, any help is appreciated.   Page:  <apex:page standardcontroller="Resourcing_Plan__c" extensions="MultipleLineItemsController">     <apex:form >         <apex:pageBlock >         <apex:pageBlockSection >             <apex:outputPanel >                 <apex:outputField value="{!rp.name}"/>                 <apex:pageblocktable>                     <apex:repeat value="{!lineItemList}" var="a">
                             <apex:inputField value="{!a.Resource_type__c}" />	                             <apex:inputField value="{!a.Weekly_commitment_fte__c}"/>	                             <apex:inputField value="{!a.Area_of_Expertise__c }"/>
                     </apex:repeat>                 </apex:pageblocktable>             </apex:outputPanel>         </apex:pageBlockSection>         </apex:pageBlock>     </apex:form> </apex:page>   Controller:  public with sharing class MultipleLineItemsController  {     public resourcing_plan__c rp {get;set;}     public list<Resource_plan_line_item__c> lineItemList{get;set;}     public MultipleLineItemsController(ApexPages.StandardController controller)      {         controller.addFields(New String[]{'name'});         rp= (Resourcing_Plan__c)controller.getRecord();         lineItemList=[select Resource_type__c, Weekly_commitment_fte__c,              Area_of_Expertise__c from Resource_plan_line_item__c where              Resourcing_Plan__c=:rp.id limit 10];         } }


How to determine top level template file in functions.php?

I am using index.php for my home page, and I am using single.php for my single post page. In my functions.php how can I determine if I am in index.php or single.php?


Showing that $\mathbb Q(\sqrt{17})$ has class number 1

Let $K=\mathbb Q(\sqrt{d})$ with $d=17$. The Minkowski-Bound is $\frac{1}{2}\sqrt{17}<\frac{1}{2}\frac{9}{2}=2.25<3$. The ideal $(2)$ splits, since $d\equiv 1$ mod $8$. So we get $(2)=(2,\frac{1+\sqrt{d}}{2})(2,\frac{1-\sqrt{d}}{2})$ and $(2,\frac{1\pm\sqrt{d}}{2})$ are two ideals of norm $2$.  Now if we can show that $(2,\frac{1\pm\sqrt{d}}{2})$ are principal ideals, then we know that every ideal class contains a principal ideal, which shows that the class number is $1$.  But how can we show that $(2,\frac{1\pm\sqrt{d}}{2})$ are principal?


Blank screen and blinking underscore after update to ubuntu 20.04 from 18.04 from

I was updating from Ubuntu 18.04 to 20.04, when the update GUI showed a certain package from python3 could not be installed and the update failed. The message then showed restart required. After restarting it is just showing blank screen and blinking underscore. I went into ubuntu recovery mode and run fsck and dpkg and then resumed, but the problem is still not solved


I'm trying to update Ubuntu 12.04 to 12.10 so I could update to most current Ubuntu. when I used the "update manager" it doesn't work.  I read that it could be corrupted and to try the code:   sudo apt-get update && sudo apt-get upgrade   then I get a screen that shows: configuring ttf-mscorefonts-installer with a box that has the EULA agreement in it.  Nothing else is showing and nothing is happening. When I click on the red X, I get a message that says a process is going on, but I don't see anything going on.  So how can I get the manager updater to work so I can update to the latest Ubuntu. I have a windows XP laptop 32 bit and I have Ubuntu as a dual boot.


Coding Form to turn dict as a function keywords

I want to pass my dictionary "param1" as the keywords of my function "simulate_x_y"  Here is what I got so far, but I never used dict that way before so I don't no how to link it with my function.  myparam1 = {"amp":1*10**-12, "amp2":1*10**-12, "sfreq":1000, "nse_amp": 1,           "noise_mu": -1.60350220266e-29, "nse_kappa": 2.49419166853e-13,           "phase_mu": np.abs(np.deg2rad(45)), "phase_kappa": 10.,           "n_epochs":120, "epoch_length": 1, "nfft":512, "freq1_start": 150,           "freq1_end": 220, "freq2_start": 150, "freq1_end": 220}  times = np.arange(0,epoch_length,1/(sfreq))  freq_band1 = np.linspace(freq1_start, freq1_end, times.size) freq_band2 = np.linspace(freq2_start, freq2_end, times.size)  def simulate_x_y(times, param1['n_epochs'], amp, amp2, freq_band1, freq_band2, phase_mu, phase_kappa, nse_amp, noise_mu, nse_kappa):     x  = np.zeros((n_epochs, times.size))     y  = np.zeros((n_epochs, times.size))     phase_shift_y =  np.random.vonmises(phase_mu, phase_kappa, n_epochs)     for i in range(0, n_epochs):         print("Simulating Epoch %s complete"%(i+1))         for j in xrange(freq1_start,freq1_end):             x[i] = x[i] + (amp  * np.sin(2 * np.pi * freq_band1 * times))             y[i] = y[i] + (amp2 * np.sin(2 * np.pi * freq_band2 * times))         x[i] = x[i] + nse_amp * np.random.normal(loc=noise_mu, scale= nse_kappa, size=times.size)         y[i] = y[i] + (nse_amp * np.random.normal(loc=noise_mu, scale= nse_kappa, size=times.size)) + phase_shift_y[i]     return x, y, phase_shift_y   Does anyone know how to do it properly, all my approaches fail because I don't know how to do it. anyone has a code snippet or example in an adequate form for me ?!


Facing NULL Pointer Exception In Java Aggregation

While learning aggregation in Java, I have come across NULLPointerException , Please help me identifying the root cause. There are 3 classes.    Student Department. Institution.  package com.java.inheritance;     import java.util.List;     import java.io.*;  public class Department {      private String name;     private List<Student> listofstudents;      Department(String name,List<Student> listofstudents){          this.name =name;         this.listofstudents = listofstudents;     }      public List<Student> getStudents(){          return this.listofstudents;     }   }    package com.java.inheritance;  public class Student {      private String name;     private int id;     private String Department;      Student(String name,int id,String Department){          this.name =name;         this.id= id;         this.Department = Department;      }  }        package com.java.inheritance;     import java.util.List;      public class Institute {         private String institureName;        private List<Department> listofDept;        public Institute(String institureName,List<Department> listofDept){            this.institureName = institureName;            this.listofDept = listofDept;        }        public List<Department> getDepartments(){           return this.listofDept;       }        // Get total number of Student in a Institute.        public int gettotalnoofStudents(){           int numberofStudent = 0;           List<Student> listofStudent=null;           for (Department dept:listofDept){               listofStudent = dept.getStudents();               for (Student student:listofStudent){                    numberofStudent++;                 }            }            return numberofStudent;       }       } // End of Institute   Now I am calling them in another class, MainClass.  package com.java.inheritance; import java.util.List;  public class MainClass {      public static void main(String[] args) {          try{           List<Student> sciencestudents=null;         List<Student> artstudnets=null;         Student s1= new Student("Asfakul",1,"Science");         Student s2=new Student("Arizul",2,"Science");         Student s3=new Student("Noor",3,"Arts");          sciencestudents.add(s1);         sciencestudents.add(s2);         artstudnets.add(s3);           Department d1=new Department("Science",sciencestudents);         Department d2=new Department("Arts",artstudnets);          List<Department> departmentlist=null;         departmentlist.add(d1);         departmentlist.add(d2);          Institute i1= new Institute("BEC",departmentlist);         System.out.println(i1.gettotalnoofStudents());         }catch(Exception e){             e.printStackTrace();             }     } }   But I am getting NULLpointerException at this point. Where have I done wrong.


Warzone 2100 occasionally zoomes my screen largly,how to fix it?

sometimes after playing Warzone 2100 for long time,when i exit the game,the desktop screen just zooms largly,and only 1/4 th screen is visible.the top bar is visible completely,but is inoperable.    i would have shared the screen shot,but the save or copy buttons are in the invisible 3/4 th part of the screen.  There is an answer already present .But it is not perfect solution,because it only allows me to restart the system,which causes certain important tasks(like downloading files) to end.  I wish to know if there is another way to zoom out the screen,which will allow me to use my pc correctly(and not just allow me to restart it).


I read about the following :     We can run several commands in the same cron job by separating them with a semi-colon (;).   * * * * * /path/to/command-1; /path/to/command-2      If the running commands depend on each other, we can use double ampersand (&&) between them. As a result, the second command will not be executed if the first one fails.   * * * * * /path/to/command-1 && /path/to/command-2   My requirements are:   the commands must be executed sequentially (wait for the current one to complete before executing the next one) the commands must be executed in the given order but every command should be executed, even if the previous one failed   What the link above therefore doesn't say is:  Does the semicolon ; approach still guarantees that the commands will be executed sequentially, and in the given order?


How do I use 'model builder' in QGIS 2.2?

I am trying to learn how to use the 'model builder' in QGIS 2.2. I have used model builder in ArcGIS, but I don't understand how to do it in QGIS 2.2?  What I want to do is to make buffers, clip vector layers and, if it's possible, add columns and data to attribute tables?  I want to do the same process for quite a few different layers, so it would be nice to get help from a model.  Is there any instructive tutorials to be found online that can show me how to make a model? I tried to google it, but didn't find what I needed.


sed search and replace last field of a line

is there a way using sed and awk to search for every last (by spaces seperated) field of a line (in a file), matching a search value (without touching the other fields even if string is matched in a field before the last one), and can that searched value be changed with an other value? 210983342900 342832423-1 i2301rw1900 309212dw90 900 9328423ABC 32091840-943543-9435 3012=32193900 301 3029432 334 210983342900ABCDE 342832423-1 i2301rw1900 309212dw90 900 9328423 32091840-943ABC3-9435 3012=32193900 301 3029432 ABC 3843209898 48435843098543098543 43985439859209438543 499 ABC  So search for ABC at every last field, and change every found value to DEFG or search for 900 at every last field and change it to 000 Can you guys break down and explain the solution?


Can a throw-in be re-taken in football (soccer)?

During corner kicks, players sometimes commit an infringement against their opponent just before the ball is in play. Then the referee blows her whistle because she is either warned by another match official or sees the infringement herself. After that, she takes the proper disciplinary action and makes the corner kick be re-taken. Should the referee follow the same procedure if a similar event happens during a throw-in?


Is it ever wrong to use the word "more" in front of an adjective? For example, is the following sentence grammatically incorrect: "I am more happy when I am reading poetry"?