Do Animals breed?
What are the rules for animal mating?
Creating a dictionary from a CSV file For $a,b,c,d \in \mathbb{R}$, is $\sqrt{a^2+b^2} + \sqrt{c^2+d^2} \geq \sqrt{(a+c)^2 + (b+d)^2}$? I have tried to show this using the fact that $\sqrt{x+y}\leq\sqrt{x}+\sqrt{y}\; $  for non-negative $x,y$ but haven't been able to arrive at a proof. How come Dropbox gets an icon in Finder sidebar? How come Dropbox gets a non-generic icon in Finder's sidebar, when other directories like Google Drive and Sites (native in OS X before Lion) all have the same generic one?    How can I customise the icons used by the folders in the sidebar? OS X used to show individual icons of all folders there — not any longer. Is there a way to know when a systemd timer will run next? I am testing a systemd timer and trying to override its default timeout, but without success. I'm wondering whether there is a way to ask systemd to tell us when the service is going to be run next.  Normal file (/lib/systemd/system/snapbackend.timer):  # Documentation available at: # https://www.freedesktop.org/software/systemd/man/systemd.timer.html  [Unit] Description=Run the snapbackend service once every 5 minutes.  [Timer] # You must have an OnBootSec (or OnStartupSec) otherwise it does not auto-start OnBootSec=5min OnUnitActiveSec=5min # The default accuracy is 1 minute. I'm not too sure that either way # will affect us. I am thinking that since our computers will be # permanently running, it probably won't be that inaccurate anyway. # See also: # http://stackoverflow.com/questions/39176514/is-it-correct-that-systemd-timer-accuracysec-parameter-make-the-ticks-slip #AccuracySec=1  [Install] WantedBy=timers.target  # vim: syntax=dosini   The override file (/etc/systemd/system/snapbackend.timer.d/override.conf):  # This file was auto-generated by snapmanager.cgi # Feel free to do additional modifications here as # snapmanager.cgi will be aware of them as expected. [Timer] OnUnitActiveSec=30min   I ran the following commands and the timer still ticks once every 5 minutes. Could there be a bug in systemd?  sudo systemctl stop snapbackend.timer sudo systemctl daemon-reload sudo systemctl start snapbackend.timer   So I was also wondering, how can I know when the timer will tick next? Because that would immediately tell me whether it's in 5 min. or 30 min. but from the systemctl status snapbackend.timer says nothing about that. Just wondering whether there is a command that would tell me the delay currently used.  For those interested, there is the service file too (/lib/systemd/system/snapbackend.service), although I would imagine that this should have no effect on the timer ticks...  # Documentation available at: # https://www.freedesktop.org/software/systemd/man/systemd.service.html  [Unit] Description=Snap! Websites snapbackend CRON daemon After=snapbase.service snapcommunicator.service snapfirewall.service snaplock.service snapdbproxy.service  [Service] # See also the snapbackend.timer file Type=simple WorkingDirectory=~ ProtectHome=true NoNewPrivileges=true ExecStart=/usr/bin/snapbackend ExecStop=/usr/bin/snapstop --timeout 300 $MAINPID User=snapwebsites Group=snapwebsites # No auto-restart, we use the timer to start once in a while # We also want to make systemd think that exit(1) is fine SuccessExitStatus=1 Nice=5 LimitNPROC=1000 # For developers and administrators to get console output #StandardOutput=tty #StandardError=tty #TTYPath=/dev/console # Enter a size to get a core dump in case of a crash #LimitCORE=10G  [Install] WantedBy=multi-user.target  # vim: syntax=dosini Difference between the use of "a" and "any" in these examples? I didn't have an idea.      I did not have any idea.   I am much more familiar with the second one. The first one sounds a bit odd to me, but sounds fine if I say:     I did not have even an idea.   But, the first one is also one of the widely used sentences by natives. What is the difference between the two? I have the following diagram:    However, this looks a bit ugly, I would like a version that looks a little bit better. For example, size the last arrow such that the T_\phi is moved to the right.  This is the code which I am using to do this:  \begin{align*}   \xi \colon &amp;\lb \to \mathcal{L}(\hh)\\   &amp;\phi \mapsto T_\phi. \end{align*}   Where \lb and \hh just give the names for those spaces. Does anybody have a suggestion how I would improve the look of this function definition? I played around with it for a while, but I simply can't figure it out.  I made a tank that fires missiles, and when the missiles hit the walls, I want them to bounce off, but I want them to bounce off to the right angle.  Right now I haven't got any obstacles, the missiles just bounce off when they get outside the viewportRectangle I made.  Is the solution I'm looking for quite advanced?  Is there a relativly simple way to do it? Compact subset in colimit of spaces Run VirtualBox in background, without a window? How to copy files into /usr/local/? (permission denied) I'm still a little new to Ubuntu and was wondering how I can copy files, in this case Aptana Studio, to /usr/local/ without being denied.   Is there a way to do it in terminal? Or a way to allow myself permission?  I should add that I am using 10.10 Desktop edition, not server. Minimum bounty on a question is now 100 rep? Let $V,W$ be nonzero normed spaces over $\mathbb{K}$ such that $V$ is finite-dimensional.  Let $E$ open in $\mathbb{K}$ and $p\in E$.  Let $f:E\rightarrow W$ be Gâteaux-differentiable at $p$.  Is $f$ necessarily Fréchet-differentiable at $p$ in this case?  I think this is not true in general, but cannot find a counterexample. What would be a counterexample? What happens to net acceleration in a non-inertial reference frame with cenripetal force? In a non-inertial reference frame, the centripetal force is balanced by a centrifugal force. Therefore, shouldn't the net acceleration be zero? Yet, you still feel an acceleration outwards? Why is that? Possible Duplicate:          Please, look at the picture?    Which calculator shows true result and how to prove achieved result? How do I prevent "Read more: www.site.com" from being injected with non-Tynt JavaScript into copy-paste actions? There are many sites that insert something like "Read more: www.site.com" into your clipboard when you copy text in your browser.  I find this abominable.  A google search reveals   to stop this if the website happens to be using the service  (by just blocking the Tynt domain), but many websites use home-grown JavaScript.  Is there a general way to block this behavior besides just turning off JavaScript?   I use Chrome but I am interested in all solutions.  EDIT: To be clear, I want to be able to keep the rest of the JavaScript functionality for these websites, since many will break without it.  EDIT #2: Here are two example websites which continue to harass me despite my use of a Tynt blocker:  |   Here are two   and two   which explain ways to implement this shady practice manually without Tynt.  Here is a  describing how hard this turns out to be to block reliably.  Here is the  I could find (March 2013) which offers suggestions on how to block this in Chrome using AdBlock, but it didn't work for me. Why is the sum of two random variables a convolution? For long time I did not understand why the "sum" of two random variables is , whereas a mixture density function sum of $f(x)$ and $g(x)$ is $p\,f(x)+(1-p)g(x)$; the arithmetic sum and not their convolution. The exact phrase "the sum of two random variables" appears in google 146,000 times, and is elliptical as follows. If one considers an RV to yield a single value, then that single value can be added to another RV single value, which has nothing to do with convolution, at least not directly, all that is is a sum of two numbers. An RV outcome in statistics is however a collection of values and thus a more exact phrase would be something like "the set of coordinated sums of pairs of associated individual values from two RV's is their discrete convolution"...and can be approximated by the convolution of the density functions corresponding to those RV's. Even simpler language: 2 RV's of $n$-samples are in effect two n-dimensional vectors that add as their vector sum.           Please show the details of how the sum of two random variables are a convolution and a sum. If I squeeze something really hard, will it ever become two-dimensional? How accurate is approximating the Earth as a sphere? What level of error do I encounter when approximating the earth as a sphere? Specifically, when dealing with the location of points and, for example, the great circle distances between them.  Are there any studies on the average and worst case error compared to an ellipsoid? I'm wondering how much accuracy I'd be sacrificing if I go with a sphere for the sake of easier calculations.  My particular scenario involves directly mapping WGS84 coordinates as if they were coordinates on a perfect sphere (with the  defined by the IUGG) without any transformation. Regionalism or just bad English? I've encountered a particular type of writing occasionally and it being, derp, in writing, it's hard to tell whether there's an accent behind it. The English used seems to me to be simply incorrect, but I can't help but feel that the following features are part of a dialect or a regional style of English. One of the most glaring (and grating) features is the substitution of &quot;saw&quot; with &quot;seen&quot;.  He seen him at the shop the other day. I seen that you were looking for... etc.  The use of &quot;away (to)&quot; is also peculiar, if not incorrect.  He was away to open the door when... He was away to get what he had asked for. etc.  I haven't come across these forms very often, and even then it was accompanied by otherwise mostly correct English, which is what makes me wonder what the hell. This is more intellectual curiosity than anything else. On found exact duplicates, should these be voted to close directly against a preferred, or ultimate, canonical question?   Or is a chain of possible duplicates (where one question is closed as duplicate of another, which itself is a duplicate of another, and so on and so on) allowable or OK?  One example of this situation can be found .