[https://example.com/] appears as a clickable link in the preview, but not in the final render when saved. This applies to at least the inline editor (tested on Stack Overflow) and question-ask page here.  Probably related bug:  also from after the change to CommonMark. (Discovered on Stack Overflow; presumably the URLs in  were clickable before the CommonMark changeover, but they aren't now. A recent suggested-edit changed a URL, but left them non-clickable, which I found surprising.  For the current version I simply removed the [] around the URLs.)
When editing a question on , I observed that a link which was not rendered in the post was hyperlinked in the edit preview (see pictures below). I tried reproducing it in the  to see if this also happens when the post is posted for the first time and observed the same. It seems to be a bug after the shift to CommonMark, leading to the different rendering of links on client and server-side. A link following a special character (without any space) is not hyperlinked in the post but is hyperlinked in the preview. A link separated from the special character with a white space appears to have no such problem. (see pictures below and my ). Link not hyperlinked in post  Same link hyperlinked in preview
I'm going to guess that the answer is "no" based on the below error message (and ), but is there anyway to perform a cross-database query using PostgreSQL?  databaseA=# select * from databaseB.public.someTableName; ERROR:  cross-database references are not implemented:  "databaseB.public.someTableName"   I'm working with some data that is partitioned across two databases although data is really shared between the two (userid columns in one database come from the users table in the other database). I have no idea why these are two separate databases instead of schema, but c'est la vie... If $f$ is continuous, then there exists $x+\frac{1}{n}\in[0,1]$ and $f\left(x+\frac{1}{n}\right)=f(x)$ Let $f:[0,1]\to \mathbb{R}$ is continuous, such that $f(0)=f(1)$. For each $n\in\mathbb{N}$, prove that $\exists x\in [0,1]$ such that $x+\dfrac{1}{n}\in[0,1]$ and $f\left(x+\dfrac{1}{n}\right)=f(x)$.   My approach: The interval $[0,1]$ is connected, then if $f$ is continuous, we have $f([0,1])\subset\mathbb{R}$ is a interval. And I suppose that, I can define a closed path such that $f(0)=f(1)$. Any hint pls, Copy from Evernote to Paste to Wordpress preserving formating Is it possible to post texts directly from the Windows desktop Evernote application to Wordpress, and retain the formating? Simple copy/past leads to format break. Flag counter is missing sporadically I noticed that on both sites where I am a moderator the flag counter is occasionally not showing any flags even when there are flags in the queue. A refresh of the page leads to the correct flag count to be displayed. I noticed this happening when I visited the site for the first time in a few hours, when I was recently active on the site the counter seems to stay accurate. $ echo $(( 255 )) 255 $ echo $(( 33 )) 33 $ echo $(( ~33 )) -34 $ echo $(( ~255 )) -256 $    and my kernel is:  $ uname -a Linux HOSTNAME 3.2.0-40-generic-pae #64-Ubuntu SMP Mon Mar 25 21:44:41 UTC 2013 i686 i686 i386 GNU/Linux     QUESTION: ~ is for negating the number AFAIK. But why does ~33 produce -34 and why does ~255 produce -256? How do remove the CD / DVD install as a source for apt-get packages when installing new features? I'm running a Ubuntu server (9.0.4 'Jaunty') as a VMware image.  It's a real pain on the odd occasion I need to install a new package to have to fish out the install CD-ROM, and make it available to the VMware image so I can continue the package install.  Is there any way to take the original installation media out of the list of source packages - I'm assuming all packages will be available on the internet.  Thanks. $ df -kh Filesystem      Size  Used Avail Use% Mounted on udev            7,8G     0  7,8G   0% /dev tmpfs           1,6G   19M  1,6G   2% /run /dev/sda2       622G  227G  364G  39% / tmpfs           7,8G  1,1G  6,7G  14% /dev/shm tmpfs           5,0M  4,0K  5,0M   1% /run/lock tmpfs           7,8G     0  7,8G   0% /sys/fs/cgroup /dev/loop1      143M  143M     0 100% /snap/inkscape/2527 /dev/loop3       79M   79M     0 100% /snap/core/1441 /dev/loop0       79M   79M     0 100% /snap/core/1577 /dev/loop4       79M   79M     0 100% /snap/core/1512 /dev/loop2       62M   62M     0 100% /snap/pencilsheep/5 tmpfs           1,6G   92K  1,6G   1% /run/user/1000   What are these /dev/loop device files? My RAM is always full. Is this related? Can WMS be used to get a local copy of raster data? Why does `a == x or y or z` always evaluate to True? Let $f_1 , f_2: I\mapsto \mathbb{R}$ bounded functions. Show that $L(f_1)+L(f_2)\leq L(f_1+f_2)$ (Riemann integral) Let $f_1 , f_2: I\mapsto \mathbb{R}$ bounded functions. Show that $L(f_1)+L(f_2)\leq L(f_1+f_2)$ where $L(F)$ is the supremum of the lower sums of the Riemann integral.  I tried to by contradicction $L(f_1)+L(f_2)&gt; L(f_1+f_2)$ and isoleting $L(f_1)&gt; L(f_1+f_2)-L(f_2)$ and usig the definition of sup.  I also tried to use $\sup(A)+\sup(B)=\sup(A+B)$ but it din't work.  Thanks. Hypothesis test for difference in medians among more than two samples Question  The test scores of three groups of people are saved as separate vectors in R.  set.seed(1) group1 &lt;- rnorm(100, mean = 75, sd = 10) group2 &lt;- rnorm(100, mean = 85, sd = 10) group3 &lt;- rnorm(100, mean = 95, sd = 10)   I want to know if there is a significant difference in the medians between these groups. I know that I could test group 1 versus group 2 using the Wilcoxon test, like so.  wilcox.test(group1, group2)   However, this compares only two groups at a time, and I would like to compare all three simultaneously. I would like a statistical test that yields a p value at the 0.05 significance level. Could someone please help?  Edit #1 - Mood's median test  Following user Hibernating's suggested answer, I tried Mood's median test.  median.test &lt;- function(x, y){     z &lt;- c(x, y)     g &lt;- rep(1:2, c(length(x), length(y)))     m &lt;- median(z)     fisher.test(z &lt; m, g)$p.value }  median.test(group1, group2)   However, this approach allows me to test for a significant difference between the medians of only two groups at a time. I am not sure of how to use it to compare the medians of all three simultaneously.  Edit #2 - Kruskal-Wallis test  User dmartin's suggested answer appears to be more or less what I need, and allows me to test all three groups simultaneously.  kruskal.test(list(group1, group2, group3))   Edit #3  User Greg Snow helpfully notes in his answer that the Kruskal-Wallis test is appropriate as long as it makes strict assumptions that make it also a test of means. Make bash exit != 0 when called by AWK and interrupted with ^C I'm having an issue with the following piece of (G)AWK script:  do {     ... } while (system("sleep 10"))   My intention is to break the loop when the user presses ^C during the sleep, but it's not working.  I believe the problem is that Bash exits with 0 when interrupted with ^C, at least when it's executed by AWK's system():  $ awk 'BEGIN { print "\n" system("sleep 2") }' (let the sleep complete) 0      $ awk 'BEGIN { print "\n" system("sleep 2") }' ^C 0   Why is it so?   Is this a bug in Bash or in (G)AWK?  Is there a simple solution that doesn't involve complicated Bash-specific syntax like trap?  The best I could come up with is this:  do {     ... } while (42 == system("sleep 10 &amp;&amp; exit 42"))   which still looks like a kludge to me. Proving the geometric sum formula by induction $$\sum_{k=0}^nq^k = \frac{1-q^{n+1}}{1-q}$$  I want to prove this by induction. Here's what I have.  $$\frac{1-q^{n+1}}{1-q} + q^{n+1} = \frac{1-q^{n+1}+q^{n+1}(1-q)}{1-q}$$  I wanted to factor a $q^{n+1}$ out of the second expression but that 1- is screwing it up... Export objects to separate files in Illustrator I have a particular situation here, In March of 1997 I travelled to the US as a tourist and lived there illegally for almost 9 years. I was never arrested, or had any trouble with the law, I was never deported. I paid my taxed (had a TFN) had a job, bank account bought a house, etc. About 9 years ago I decided to leave as I was tired of living like that, not able to be legal, in fear of deportation and loosing everything. I also got married (to a person in the exact situation as me) we were able to legally migrate to Australia and now we are Australian citizens. We never returned our I-94s and in 2005 left through Mexico (walked through the border) so there are no records of us ever leaving. We have lived here in Australia for over 9 years.  OK so my question is... We have been thinking we would like to visit our friends and family back in the US now that we have a little girl. Is there any chance they won't let us in because they know we overstayed? We would be travelling with our Australian passports. What is the difference between "var=${var:-word}" and "var=${var:=word}"? Markov/Chebychev inequality If Z is a square integrable random variable such that $E[Z]&gt;0$, then prove that  $$P(Z\geq k) \geq \frac{(E(Z)-k)^2}{E(Z^2)} \forall k \in [0,E(Z)]. $$  This is a homework question and I don't even understand why the inequality is reversed comparing to Markov/Chebychev inequality. Should Cauchy-Schwartz inequality be used? If yes, then how to begin? Thanks a ton! Hoping someone can give me some thoughts on what might be going on here so I can be a bit more informed when I call a plumber.  Situation is, we got our water heater replaced a few years back and ever since this has been an issue. It's more noticeable when it's cold outside it seems, but still seems to be a year round problem. Whenever we  use hot water, we basically run out of it within minutes. In order to get an acceptable amount of hot water (enough to take a 10 minute shower), we literally have to prime the water first. By that I mean I have to turn on the hot water, let it run for a couple of minutes, then turn it off and wait 20 minutes. Then when we go to use the hot water again we'll get hot water for a respectable amount of time. Now I am fairly ignorant to all this, but it seems a 71 gallon hot water heater should be capable of holding enough water to not need to be primed like this. I should be able to take a 30 minute shower, let alone 10 without running out. My shower this morning was decently warm for maybe 2 minutes before it was just warm-ish.   So if anyone can give me some ideas on what might be going on I would appreciate it. We've just put up with this for some years assuming perhaps it was some eco friendly thing. Like the system doesn't maintain much hot water in the tank so it's not always running and only heats water up when you start to use it? I hope that isn't the case though and even so, I should be able to get more hot water out of it. Any help?  UPDATE Sorry everyone, I meant to tell you all that the water heater was gas. The pilot light is lit. I don't recall the specific model though I can look that up if people think it will help. I have actually turned up the thermostat on it above the default and when the water heater is putting out hot water, it can be very hot. Too hot. But again, that requires us to prime it before we get any decent amount of hot water out.  UPDATE 2 Looked it up, I believe this is the model info if that helps anyone: State Select: High Output. Model number: GS675XRRS 300 Why doesn't hydrogen gas exist in Earth's atmosphere? The root mean square velocity of hydrogen gas at room temperature is: Gas constant: $R=8.31\ \mathrm{J\ K^{-1}\ mol^{-1}}$ Molar mass of hydrogen gas: $M=2.02\times10^{-3}\ \mathrm{kg/mol}$ $$\begin{align} v &amp;= \left(\frac{3\times8.31\ \mathrm{J\ K^{-1}\ mol^{-1}}\times300}{2.02\times10^{-3}\ \mathrm{kg/mol}}\right)^{\frac12}\\ &amp;= 3356.8377\ \mathrm{m/s}\\ &amp;= 3.356\ \mathrm{km/s} \end{align}$$ The escape speed of Earth is $11.2\ \mathrm{km/s}$, which is larger than the root mean square velocity of hydrogen gas. But still, hydrogen gas doesn't exist in Earth's atmosphere. Why? Have I made any mistakes in my calculations? Why did Bane/Smith cut himself? In the Matrix part II and the beginning of part III the crew member who was infected by Agent Smith (Bane) cuts himself.   The female crew member in part III who brought Trinity food told her the same and speculated that they might be "VDT's".  I don't fully understand this. What are VDT's and why would Agent Smith engage in self-cutting unless he has borderline personality disorder or depression or something?