Tradeoffs around using a query string vs embedding version number in the CSS/JS files
What's the best way to version CSS and JS URLs?
Prove that the Interior of the Boundary is Empty Suppose X is a Metric Space  Let S $\subset X$  Prove that if S is Closed then, the Interior of the Boundary of S is Empty  Totally stuck on how to solve this. Which hydroxyl from either the phosphate or the glycerol is taken during synthesis of a phospholipid head? I listened to this on audiobook and it was great.  The premise was a human ends up travelling to an alien planet. The aliens have a perimeter to their 'base' that is under constant attack from the planet's animals. It is revealed towards the end that there is some sort of signal being transmitted that is making all the animals and plant life attack a certain point on the planet (where the aliens are).   Other major plot points I remember: The human traveller falls in love with an alien. The aliens have a sort of virtual training environment that simulates life outside the perimeter, where plants attack you etc. There is a secondary alien group that the human ends up with, and although they are rivals to other group, they have a trade set up.   Any help much appreciated! Thanks. 554 5.7.1 : Relay access denied centos postfix I have problem in send mail from postfix in centos  I have following  for sending mail but I am getting error.  As in the link I tried following commands  telnet localhost smtp  Trying ::1... Connected to localhost. Escape character is '^]'. 220 mydomain.com ESMTP Postfix ehlo localhost 250-mydomain.com 250-PIPELINING 250-SIZE 10240000 250-VRFY 250-ETRN 250-ENHANCEDSTATUSCODES 250-8BITMIME 250 DSN mail from:&lt;domain.com&gt; 250 2.1.0 Ok rcpt to:&lt;test@gmail.com&gt; 554 5.7.1 &lt;test@gmail.com&gt;: Relay access denied   Edit-1  In terminal this works  echo TEST | mail -v -s "Test mail" testing@gmail.com   my postconf -n shows belog information  alias_database = hash:/etc/aliases alias_maps = hash:/etc/aliases command_directory = /usr/sbin config_directory = /etc/postfix daemon_directory = /usr/libexec/postfix data_directory = /var/lib/postfix debug_peer_level = 2 home_mailbox = Maildir/ html_directory = no inet_interfaces = localhost inet_protocols = all mail_owner = postfix mailq_path = /usr/bin/mailq.postfix manpage_directory = /usr/share/man mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain mydomain = dummy.com myhostname = dummy.com mynetworks = all mynetworks_style = host myorigin = $mydomain newaliases_path = /usr/bin/newaliases.postfix queue_directory = /var/spool/postfix readme_directory = /usr/share/doc/postfix-2.6.6/README_FILES sample_directory = /usr/share/doc/postfix-2.6.6/samples sendmail_path = /usr/sbin/sendmail.postfix setgid_group = postdrop unknown_local_recipient_reject_code = 550   What configuration I have to perform to send mails from my server. I'm installing a brand new motion activated security light to an existing box on my garage. After removing the old light, I notice it only has white/black wiring while the new light fixture has of course white/black/green (ground) wires to attach. What do I do if no ground wire is available with the old box? Will metering from a DSLR apply to a film SLR? I still like to shoot with film (I use a Nikon F3) but I like the immediate feedback of digital.  I'm thinking of buying a used DSLR to help me get the framing and lighting right when I shoot static subjects.  Then I'd take the final shot with my F3. But would the metering be transferable?  If the shot looks perfect at 1/125 with f/2 on a DSLR, will the same settings work on a film camera? When I'm about to install a program in the terminal it wants the password:  [sudo] password for xxx:   But when I start to type my password nothing happens. What should I do? Where does the word "torsion" in algebra come from? Image viewer without large window borders I am looking for an image viewer software without very large window borders. I don't need any type of toolbar, just a simple image viewer.   It would also be fine if there is no top bar to close, minimize or maximize window. Splitting lines by polygons in QGIS I have a river network (lines) and a .shp with states (polygon). I would like to split the lines at the state boundaries i.e. split lines by polygon boundaries. Is there a geoprocessing tool to do this in QGIS? I can't merge the lines by the way, since they are meaningfully split into tributaries/main river. Fastest Gun in the West Problem Is the convex hull of closed set in $\mathbb R^{n}$ is closed? Is convex hull of closed set in $\mathbb R^{n}$ closed? Usage of "second/third/fourth ... last" In German there is a pattern for counting items from the end of a list. The last item is "das letzte", the one before is "das vorletzte", the one before that is "das vorvorletzte" and for each other item there's just another "vor" added.  While searching for an English translation for the German word "vorvorvorletzte" I came across   and  but none of them showed any usage pattern. Furthermore I didn't find any indication of which variant ("to", "from", no preposition) is used most nor to what area of the world those translations apply.  So I am still wondering: When there are items 1, 2, 3, 4 and 5, how can/will item 2 be called?   third from last? fourth from last? anteantepenultimate? fourth-last? fourth to last? the last but three item? the last but four item?   Is this a question of dialect/local use? How to unlock gungeoneers I've seen on a wiki that there is a ghost gungeoneer and a robot gungeoneer but it didn't say how to unlock them, so how do I unlock more gungeoneers ? Previous posts                  As of today, the Moderator Flag Dashboard is officially graduated and the old version sent to the smelter's yard.  Based on stats from the past month, virtually all moderators were already on the new UI (thank you) so you hopefully won't notice any change.  That said, I would like to highlight the handful of improvements we made over the last month and a half based on your feedback:   A more responsive navigation bar at the top of moderator pages, improving the mobile experience. Similarly, , increasing room on the screen for the first question. . .  Not only do the headers look better, they now function better.  Now you scroll to and highlight the post/comment each time you click the link, not just the first time. .  Posts by the same user are grouped together and ordered newest first. .  We eliminated the VLQ (auto) side effect so now "Resolve all flags (auto)" doesn't do anything surprising.  If you still want to leave a comment or decline, you can do so with the buttons next to the individual flags.   Bugs and Feature Requests  Since this project is officially launched, all bugs and feature requests should be done in the form of questions tagged  on MSE, not answers on this post.  Feel free to post an answer here if you have specific concerns about the release process. Have we completed Diablo 3 in 9 hours? My friend and i decided to play some Diablo 3. We played for almost 9 hours straight and killed Diablo on the hard difficult. We reached level 41.  We think 9 hours is short for a game like Diablo 3.   Have we missed something? Why are we only level 41? Is there more story? Why I can't scan the WhatsApp QR? Why I can't scan the Whatsapp QR?   I reinstalled WhatsApp  I already have the WhatsApp Web Option  I put it to scan but it just doesn't scan it. I Installed a QR Scanner app and it works perfectly. I uninstalled the QR Scanner app to see if that was the issue and still doesn't work.   My phone is a Samsung Galaxy Ace. We are getting  in M19. What if I enchant my , copying my opponents . Then I pay the cost on my Bolas (previously a Delver) to activate his transform ability.  What will happen? I can think of 3 possibilities:   My Delver is exiled and the aura goes to the graveyard. My Delver is transformed, aura goes to the graveyard, but the Delver transforms into  My Delver is transformed, aura goes to the graveyard, and the Delver transforms into Inversion in "only [adverb] have they" I have seen this construction quite often:      Online ads have been around since the dawn of the Web, but only in   recent years have they become the rapturous life dream of Silicon   Valley.   What is the rule there?. When your sentence doesn't start with pronoun + verb, invert them as verb + pronoun?. I know it sounds awkward but is it possible (grammatically correct) to use something similar to:      Online ads have been around since the dawn of the Web, but only in   recent years they have become...   And in any case, does this only work with have (or has)? Maybe it works fine with 'had' but I can't think of an example right now. I know that Dirichlet function has uncountable many discontinuities. I think they are removable, because the discontinuities can be removed by redefining the function values of the rational numbers as 0.  So Dirichlet function is a function that has uncountable many removable discontinuities, then my question is can we construct a function with uncountable  many jump discontinuities? If not, how do we prove it is impossible? Thank you.  An odd but similar question is can we have a function that has uncountable many infinite discontinuities?