"And God said......and there was light." What does these equations mean?
What is the meaning of this "let there be light" joke?
Before upgrading to macOS Sierra, I really liked the Character Accent Menu by doing a long press on a key (for example, the character e) and being able to add an accent on it.   However, this functionality seems to not work anymore, and so far, I can't find out why?   Also, before, doing a long press on the delete button, would repeatly delete characters. Now, it is doing only one character deletion disregarding how long I'm pressing the key. So if I want to erase 10 characters, I need to press the delete button 10 times...  Also, I am not able to log off or shut down. When doing it, all applications are closed, status bar disappears but nothing happens. The dock remains here. I have no way to shut down or log out without doing a long press on the power button.  Is someone facing the same issue?  EDIT : Logging with a new user account or guest account fix all the problems. But I still would like to know what, in my user account, became corrupted during the upgrade. I'm refactoring my ASP.net application from ASP.net 3.5 to 4.0. Also I'm changing the URLs to user friendly URLs /product.aspx?id=100 to /product-name/100.  All my pages are indexed by search engines and the site has already been online for 6 years. I'm planning to do 301 redirect from the old pages to the new one.  I want to make sure I won't lose the rankings and traffic.  Any suggestion how to do it properly? I asked a question  but, rather stupidly, added extra information after it had been answered.  My additional question is this: I have a table with varying lengths of words. I want to encircle different groups of cells, including diagonals. If possible, it would be great if the rectangles don't overlap each other where possible.  I looked at the answer , which, whilst tedious, worked except for the overlap.    This is where I've got to so far:  \documentclass[fleqn,12pt,a4paper,landscape]{article}  \usepackage{tikz} \usepackage{tabularx}  \begin{document}  % Introduce a new counter for counting the nodes needed for circling \newcounter{nodecount} % Command for making a new node and naming it according to the nodecount     counter \newcommand\tabnode[1]{\addtocounter{nodecount}{1} \tikz \node     (\arabic{nodecount}) {#1};}  % Some options common to all the nodes and paths \tikzstyle{every picture}+=[remember picture,baseline] \tikzstyle{every node}+=[inner sep=0pt,anchor=base, minimum width=1.8cm,align=center,text depth=.25ex,outer sep=1.5pt] \tikzstyle{every path}+=[thick, rounded corners]  \begin{table}[ht]   \begin{minipage}[b]{1 \linewidth}\centering    \begin{tabular}{cccccc} % Turn the cells needed for defining the circling paths into nodes with our     custom command \tabnode{Long ago}&amp; \tabnode{A few days ago}&amp; \tabnode{Day before         yesterday}&amp; \tabnode{Yesterday} &amp;  &amp;  \\      &amp; &amp; &amp;  &amp; \tabnode{Today} &amp; \tabnode{Now}\\      \tabnode{Long time in the future}&amp; \tabnode{A few days on}&amp;     \tabnode{Day after tomorrow}&amp; \tabnode{Tomorrow} &amp;  &amp; \\      \end{tabular}    \end{minipage}   \begin{tikzpicture}[overlay] % Define the circle paths \draw [blue](1.north west) -- (1.north east) -| (7.north east) |- (7.south     west) |- (1.north west); \draw [red](8.south west) -| (2.north east) -| (2.south west) |- (8.south     west); \draw [yellow](9.south west) -| (3.north east) -| (3.south west) |- (9.south     west); \draw [green](8.south west) -| (3.north east) -| (2.south west) |- (8.south     west);   \end{tikzpicture}  \end{table} \end{document}  %%% Local Variables:  %%% mode: latex %%% TeX-master: t %%% End: When writing a book and referring to a female and male aged 18–25, what term would be most appropriate? Boy and girl seem too young, whereas man and woman seem too old.  Example sentence:     A boy/man emerged from the shadows.   Edit: I think the word I am looking for is similar to 'guy' but less American and colloquial. Any thoughts? Is there any way you could revive Guest Sessions in a future LTS distro?  Guest sessions are good security - they give me just enough power to do what I need to do on a daily basis without risking my system. In short, Guest sessions save me from myself.  I had upgraded from 16.04 to 18.04, gotten a problem I couldn't fix and was all to happy to wipe and rebuild my hard drive and return to 16.04.  I can't be the only one who feels this way. Are there any expressions that describe going from a bad to a worse situation? Are there idioms or expressions in English that describe going from one bad situation to one that's even worse?  I heard "between a rock and hard place" but this describes a dilemma not really a transition. I am looking for an expression that describes someone trying to get out of a bad situation but after much effort, the situation only got worse. How does \fontsize{}{} work? Splitting of prime ideals in algebraic extensions I was reviewing  for , and noticed that nobody voted to close it, even though the page reports a duplicate.      Why does this happen? Indent math blocks? I want all math blocks \begin{math} in my document to be intended automatically, like it's the case with \begin{itemize}.   Can anyone please give me a hint on how to do this? Thanks :-) I'm in trouble with time dilation: Suppose that there's two people on the Earth (A,B), they are twins and each other has a clock. (So they are at the same reference frame). B travels in a spaceship and is orbiting around the Earth, as B's speed has increased there's some time dilation. So it's supposed that if A "looks" to B, B's clock will run slower than A's, and viceversa. And if one day B decides come back to the Earth, he will be younger than his twin and the hour of his clock would be different (earlier than A's clock) because of time dilation.  My first question is, why each person see the other's clock as the slow one? (In fact, I found some information that may solved it but I'm not sure if it's the right answer, and if it is, I don't understand it. -> It's because everyone thinks about himself as the reference frame. In other words, that for B, he is the stationary and who moves is A, so he sees A's clock run slower as B is "stopped" and the same for A. B is who is moving and A the stationary.)  The other question I have is that if it's true that each one sees the other as the slow one there's something that i missed out. We all agree that B (after going to the space and came back to the Earth) he is younger than his brother. So, why B don't see A moving and aging very fast if A see his brother and his things going very slow? Let's imagine they were looking to each other all the time, if both of them see the other going slowly once they meet and "discover" B is the young one... how is that possible?  [I think that in one episode of Cosmos of Carl Sagan (though may be I'm mistaken) he said that a neutrino "borned" in the Big Bang could have seen the creation of the Universe until today in few seconds due to its high speed, here starts my doubts: or i misunderstood something or there's contradictory information]  (I don't know anything about physics, only what is taught at high school as I'm a teenager so it'd be better to answer with no kind of calculation as I'd not understand it.) Microdisplacements with adaptive subdivision turning black What is a decoupling capacitor and how do I know if I need one? What is a decoupling capacitor (or smoothing capacitor as referred to in the link below)?  How do I know if I need one and if so, what size and where it needs to go?    mentions many chips needing one between VCC and GND; how do I know if a specific chip is one?   Would an  4-bit parallel access shift register used with an Arduino need one? (To use my current project as an example) Why or why not?  I feel like I'm starting to understand the basics of resistors and some places they're used, what values should be used in said places, etc, and I'd like to understand capacitors at the basic level as well. Why can't I sort questions by "votes" or "unanswered" without logging in? On the "Questions" page of each Stack Exchange site, there are links at the top to sort the questions by "newest", "frequent", "votes", "active", and "unanswered".  At least that is what it looks like if I am logged in. If I am on a site that I don't have an account for, or if I am not logged in, the only one I see is "newest".  This seems to have been done recently. I could swear I saw the other links, even when I was not logged in, until a few weeks ago, or maybe later than that.  Why was this change made? What is the term for accusing a person of mischief through invented, twisting and changeable terminology? What is the term for accusing a person of invented wrongdoing in such a way that he cannot respond or even clearly understand the accusations? For example, frequently reversing the definitions of the terminology used, or basing argumentation on hints and roundabout phrasings, metaphors, invented-on-the-fly floating definitions and rules to fit with the accusations.    Update: I think inquisitorial is the most proper term for context in which the result does not depend on the argumentation of one of the sides.    Though, jargonaut was completely unheard by me and incrementally more useful. I have a large array in C (not C++ if that makes a difference). I want to initialize all members of the same value.  I could swear I once knew a simple way to do this. I could use memset() in my case, but isn't there a way to do this that is built right into the C syntax? Using wired and wireless headphones simultaneously? I have 1 android device, 1 wired headphones, 1 wireless headphones, 2 ppl willing to watch film.  When I connect both of headphones only wired work.  Is it possible to use both of headphones simultaneously? disable comments if array exists This is the code which is registering the function for rewrite_endpoints():   function wpa121567_rewrite_endpoints(){  add_rewrite_endpoint( 'comments', EP_PERMALINK );  add_rewrite_endpoint( 'stats', EP_PERMALINK );  }  add_action( 'init', 'wpa121567_rewrite_endpoints' );   NOTE  I don't know if this matters but I will write it.   I have single-CPT.php which is calling  /inc/post-format/single-CPT.php like this:      &lt;?php while ( have_posts() ) : the_post(); ?&gt;  &lt;?php   get_template_part( 'inc/post-format/single-debate');      ...   This is the code which is checking if array key exists, which is  inside my /inc/post-format/single-cpt.php:   ?php if( array_key_exists( 'comments', $wp_query-&gt;query_vars ) ){  the_field('comments_section');   } elseif( array_key_exists( 'stats', $wp_query-&gt;query_vars ) ) {   the_field('stats_section');   } else { // the request is for the main post  }   ?&gt;   This is my comments.php :       &lt;div id="comments" class="comments-area"&gt; &lt;?php // If CPT and not logged in, display a message: if ( 'debate' == get_post_type() &amp;&amp; ! is_user_logged_in() ) { echo '&lt;p class="must-log-in" style="padding-left:20px; font-size:20px;"&gt;You must be logged in to post a comment.' . '&lt;/p&gt;';  echo do_shortcode("[upme_login]");   } ?&gt;     &lt;?php if ( have_comments() ) : ?&gt;         &lt;h3 class="comments-title"&gt;              &lt;?php                 printf( _n('%d comment', '%d comments', get_comments_number(), 'outbox' ),                     number_format_i18n( get_comments_number() ) );             ?&gt;         &lt;/h3&gt;             &lt;ol class="commentlist"&gt;              &lt;?php                 wp_list_comments( array( 'callback' =&gt; 'outbox_comment' ) );             ?&gt;         &lt;/ol&gt;&lt;!-- .commentlist --&gt;          &lt;?php if ( get_comment_pages_count() &gt; 1 &amp;&amp; get_option( 'page_comments' ) ) : // are there comments to navigate through? If so, show navigation ?&gt;         &lt;nav role="navigation" id="comment-nav-below" class="site-navigation comment-navigation clearfix"&gt;             &lt;div class="nav-previous"&gt;&lt;i class="icon-left-open-1"&gt;&lt;/i&gt;&amp;nbsp;&lt;?php echo get_previous_comments_link( __( 'Older Comments', 'outbox' ) ); ?&gt;&lt;/div&gt;             &lt;div class="nav-next"&gt;&lt;?php echo get_next_comments_link( __( 'Newer Comments', 'outbox' ) ); ?&gt;&amp;nbsp;&lt;i class="icon-right-open-1"&gt;&lt;/i&gt;&lt;/div&gt;         &lt;/nav&gt;&lt;!-- #comment-nav-below .site-navigation .comment-navigation --&gt;         &lt;?php endif; ?&gt;      &lt;?php endif; // have_comments() ?&gt;      &lt;?php         // If comments are closed and there are comments, let's leave a little note, shall we?         if ( ! comments_open() &amp;&amp; '0' != get_comments_number() &amp;&amp; post_type_supports( get_post_type(), 'comments' ) ) :     ?&gt;         &lt;p class="nocomments"&gt;&lt;?php _e( 'Comments are closed.', 'outbox' ); ?&gt;&lt;/p&gt;     &lt;?php endif; ?&gt;     &lt;?php  // Don't output the comment form if CPT and user isn't logged in if ( 'debate' != get_post_type() || is_user_logged_in() ) {  comment_form(); }  ?&gt;  &lt;/div&gt;&lt;!-- #comments .comments-area --&gt; &lt;?php } ?&gt;    This is how the comments template is included  inside my single-CPT.php :  if ( comments_open()  )  comments_template( '', true );   I want to disable comments if if( array_key_exists( 'comments', $wp_query-&gt;query_vars ) ){  How can I do this? Getting a File's MD5 Checksum in Java I am looking to use Java to get the MD5 checksum of a file.  I was really surprised but I haven't been able to find anything that shows how to get the MD5 checksum of a file.  How is it done? Can I use my laptop as a second monitor?