Why there cannot be source-free spherical symmetrical EM disturbances?
Why does a monopole not radiate energy in electodynamics?
Android app chokes on per-site meta profiles Steps to reproduce:    Go to a per-site meta. Find any post. Touch the user that posted it. See something like this (click to enlarge):           As you can see, it says "Stack Overflow" as the site, and shows my SO rep and badges, but it shows my Meta.Code Golf posts. Different mechanics of \hyperlink vs. \hyperref I am fiddling around with the hyperref package to build a hypertext structure into my pdf. At first glance, hyperref provides two similar macros to put links between parts of my document: \hyperlink{target}{text} and \hyperref[target]{text}. You might notice their slightly different syntax. What really interests me is their different working mechanics. I will illustrate this by the following example: \documentclass{article}  \usepackage{pdfpages} \usepackage[]{hyperref} \usepackage{mwe}  \begin{document}  \section{Section Heading} \label{sectionheading}  \includepdf[link=true, linkname=pdfpage]{example-image}   Link to section works with \hyperref[sectionheading]{hyperref} and with \hyperlink{sectionheading}{hyperlink} (but with slightly different targets on the page).  Link to pdf works with \hyperlink{pdfpage.1}{hyperlink} but not with \hyperref[pdfpage.1]{hyperref} (and not this way, either: \hyperref[pdfpage]{hyperref}).  \end{document}  To link to the labeled section heading, I may use both commands. While \hyperref directs my pdf viewer directly to the linked section, \hyperlink directs me somewhere slightly different, so I can see more context. To link to the \includepdf of pdfpages however, I may only use \hyperlink. \hyperref does not work at all. I suspect this is because of a subtle difference in their working mechanisms. While checking the aux file, I found a line \newlabel{sectionheading}{{1}{1}{Section Heading}{section.1}{}} which \hyperref seems to use as a target. However, I did not find any similar target for the included pdf. My question: I suspect, I understand the workings of \label and \ref very well. \hyperref seems to work quite similarly with the added clickability. Could you please explain to me how \hyperlink does work differently and how it is implemented? E.g. what mechanics explain the difference when clicked on the link and where and how are the link targets stored in the first place? Conditional clause (then) In this first instance the main clause only stands alone if you  omit (then).  But in the other example it clearly has a main clause. So would this be classed as an embedded main clause as it only works as a independent clause if it's adjusted and or if it's joined with a dependent clause.  If I have enough money, then I will buy a new car.  If it rains, the picnic will be cancelled.  The picnic will be cancelled if it rains. Elected moderators can nominate themselves , and I can nominate myself again, despite having won the first round of election.    I understand this isn't going to be easy to fix, given that SE only knows about community mods, employees and developer roles, and pro-tempore mods need to be able to nominate themselves. When no model comparison, should I use REML vs ML? I'm running LMM, and I will make no comparison of models. Could I ask which one should I use between REML and ML? Generating DLL assembly dynamically at run time Currently I have some code that is being generated dynamically.  In other words, a C# .cs file is created dynamically by the program, and the intention is to include this C# file in another project.  The challenge is that I would like to generate a .DLL file instead of generating a C# .cs file so that it could be referenced by any kind of .NET application (not only C#) and therefore be more useful. Lagrangian and Hamiltonian EOM with dissipative force I am trying to write the Lagrangian and Hamiltonian for the forced Harmonic oscillator before quantizing it to get to the quantum picture. For EOM $$m\ddot{q}+\beta\dot{q}+kq=f(t),$$ I write the Lagrangian  $$ L=\frac{1}{2}m\dot{q}^{2}-\frac{1}{2}kq^{2}+f(t)q$$ with Rayleigh dissipation function as   $$ D=\frac{1}{2}\beta\dot{q}^{2}$$ to put in Lagrangian EOM $$0 = \frac{\mathrm{d}}{\mathrm{d}t} \left ( \frac {\partial L}{\partial \dot{q}_j} \right ) - \frac {\partial L}{\partial q_j} + \frac {\partial D}{\partial \dot{q}_j}. $$  On Legendre transform of $L$, I get $$H=\frac{1}{2m}{p}^{2}+\frac{1}{2}kq^{2}-f(t)q.$$  How do I include the dissipative term to get the correct EOM from the Hamiltonian's EOM? Difference between ' and " on command line (bash)? "...programs that each perform..." vs "...programs that each performs...": which is correct? TP-LINK TL-WN823N Unable to connect to network I have purchased a TP-LINK TL-WN823N (EU) V2.0 device, which is a USB device that should work as a Network Interface Card, allowing me to connect my computer to wireless networks. Unfortunately, I am unable to find any wireless networks using this device using either wicd or network-manager (no networks appear in the list of networks supplied by either application).  A CD came with the device claiming "Linux support". The CD contained a URL to a corrupted archive file for downloading installation resources. I try to mask my immense frustration.  Here is the additional dmesg output I receive when I connect the device to my computer (similar content is present when I boot the computer with the device connected):  [17096.009912] usb 2-1.2: new high-speed USB device number 4 using ehci-pci [17096.103501] usb 2-1.2: New USB device found, idVendor=2357, idProduct=0109 [17096.103513] usb 2-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [17096.103527] usb 2-1.2: Product: 802.11n NIC [17096.103529] usb 2-1.2: Manufacturer: Realtek [17096.103530] usb 2-1.2: SerialNumber: 00e04c000001   This is my lsusb, where the offending device corresponds to Bus 002 Device 004:  Bus 002 Device 003: ID 0a5c:5800 Broadcom Corp. BCM5880 Secure Applications Processor Bus 002 Device 004: ID 2357:0109   Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 001 Device 004: ID 0c45:6433 Microdia  Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub   As lsusb -v:   It seems the device is working to me, but no new interface is found in 'ifconfig':  docker0   Link encap:Ethernet  HWaddr 02:42:6e:bf:92:16             inet addr:172.17.0.1  Bcast:0.0.0.0  Mask:255.255.0.0           UP BROADCAST MULTICAST  MTU:1500  Metric:1           RX packets:0 errors:0 dropped:0 overruns:0 frame:0           TX packets:0 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:0            RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)  enp0s31f6 Link encap:Ethernet  HWaddr 30:5a:3a:e1:96:b1             UP BROADCAST MULTICAST  MTU:1500  Metric:1           RX packets:0 errors:0 dropped:0 overruns:0 frame:0           TX packets:0 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:1000            RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)           Interrupt:16 Memory:df200000-df220000   lo        Link encap:Local Loopback             inet addr:127.0.0.1  Mask:255.0.0.0           inet6 addr: ::1/128 Scope:Host           UP LOOPBACK RUNNING  MTU:65536  Metric:1           RX packets:412 errors:0 dropped:0 overruns:0 frame:0           TX packets:412 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:1           RX bytes:31876 (31.8 KB)  TX bytes:31876 (31.8 KB)   Running 'lshw -class network' as root contains only information about the 'enp0s31f6' interface.  Additionally for sanity, my 'uname -a':  Linux home-z170a-ubuntu 4.4.0-22-generic #39=Ubuntu SMP Thu May 5 16:53:32 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux   I am using Ubuntu 16.04.  My questions are:   Why are no networks present in the list for wicd or network-manager? Why is there no additional network interface created when I plug in the USB device? Is it possible to create this network interface?   Thanks for reading. Pumpkin Noodles is a thing or are a thing? Which of the following is correct?  How come pumpkin noodles is not a thing?  or  How come pumpkin noodles are not a thing?  I want to post one of the above statements to Twitter with a picture of a bowl of pumpkin noodles i.e. the stuff that comes out of a hollowed out pumpkin. Why do I have blurred vision and how do I fix it? How do I fix this "E: Type '*' is not known on line * in source list ..." update error? How can I check if my computer's powerful enough to run a certain game? Solving the recurrence $T(n) = \sqrt n T(\sqrt{n}) + \sqrt{n}$ From , page 209:     Dividends   Dividends are income paid by investments. Both bond funds   and stocks can  pay dividends. Bond fund dividends (the interest paid   by the individual  bonds in a fund) tend to be higher (as a percentage   of the amount you have  invested in a fund). When a dividend   distribution is made, you can receive  it as cash (which is good if   you need money to live on) or reinvest it into  more shares in the   fund. In either case, the share price of the fund drops to  offset the   payout. So if you’re hoping to strike it rich by buying into a bunch    of funds just before their dividends are paid, don’t bother. You’ll   just end up  paying more in income taxes.    It is talking about mutual funds.   I've never played with stocks.  However, I would like to know more about it.  Does the bold text imply the stock price will drop because of a company giving out a dividend? Prove Uncountable set minus a countable set is uncountable Let B be a countable set, and let A be an uncountable set. Prove that A-B is uncountable Import a python module without the .py extension Google search results showing up a URL on its search which doesn't exist on the website I am using a keyword to display a website page on google search. After entering the keyword, on the first page of google, I am redirected to a page, whose domain is exactly similar to the website whose page I want to display, but it is showing a page which doesn't even exist on the domain. Also, as similar domain with spam characteristics is also getting displayed.   To practically demonstrate this issue, do follow the below steps.   Go to  Type dolce streichquartett and click on search. The 4th/5th URL has this link http://www.dolce-streichquartett.de/?high_ry=/casinos/de/spielautomaten-casino-bregenz.php, which is no where on the website and looks like spam The 7th/8th link you see is http://deonlinecasino.org/doc/kostenlos-roulette-spielen-spielgeld-ausdrucken.php, which is exactly similar to the above with the title as the keyword but a different domain.   What is this issue and why is this happening? Too long in Primary Fermentation? What's the maximum amount of time for primary fermentation, assuming the beer is going straight to bottles next? Will it over ferment and then fail to carbonate, if left too long in a carboy?