It is possible to type emojis in SE questions, answers and comments. Although I have never actually seen another user do it, I managed to do it accidentally and the emojis look ugly and do not fit in with SE's look.  We should, therefore, disallow emojis in comments and posts.  Examples of emojis:   LOL: 😂 Fire: 🔥 Heart: ❤
Today I found my first ever (to the best of memory) emoji in a post.        Having no idea this was even possible I came here looking for some history. I found there is an  tag. There seems to be consensus that they add little to no value on SE per  &amp;  we also know they don't translate well on all devices    I don't find any history other then this one post  where there is any focused attempt to support them. I don't find any history of discussion on supporting them.    Two questions   Is it possible to disable emojis across Stack Exchange?   If yes   Should we disable emojis across Stack Exchange?
How to get WordPress' hooks/actions run sequence? In what order add_action hooks execute? i.e. init wp_head wp_footer after_theme_setup  etc... ??? ??? ???     EDIT: I've also posted my solution. From :  Error propagation It was common to discuss the &quot;error propagation&quot; properties as a selection criterion for a mode of operation. It might be observed, for example, that a one-block error in the transmitted ciphertext would result in a one-block error in the reconstructed plaintext for ECB mode encryption, while in CBC mode such an error would affect two blocks.  I read  similar post before. And I can understand that in CBC decryption, only two blocks are affected due to error propagation (error in 1 block). But, for the same case in CBC encryption, why are still only two blocks affected? It looks like all the following blocks will be affected. This is a  about  the use of a *AMPP's stack.    I recently had a talk with some experienced people and they suggested to me not to use a WAMP stack, and instead install apache, mysql and php separately.  I don't understand why they have suggested this, though, so can anyone tell me?  Is there a particular disadvantage of WAMP, or a particular advantage to installing all of them separately?  Since a WAMP stack itself is composed of apache, mysql and php, then what's the difference between using the WAMP stack and installing them all separately? When electric dipole placed in non uniform electric field, what is the approach to calculate torque acting on it? Can it be zero? X,Y,Z missing in F3 When I press F3 to see the debug screen in I use Minecraft 1.8.1, some information is missing.   Most notably, there are no X, Y, Z coordinates.     What happened to my debug overlay? I took some shots recently and I noticed that I'm getting a lot of little black dots in my images.  I cleaned my lens thoroughly with the Nikon camelhair brush and retook the pictures but once again, the dots appear.  I'm shooting with a Nikon D7000 and using a starter lens. I've attached an example (notice the black spots on the chairs, on the ceiling, etc). Show that $\text{C}/c \cong (c/(\text{C}^{\text{op}}))^{\text{op}}$ I'm self studying from Category Theory in Context by Emily Riehl and have encountered the following question regarding slice categories:     Let $\text{C}$ be a category and $c$ be an object in $\text{C}$. Show that $\text{C}/c \cong (c/(\text{C}^{\text{op}}))^{\text{op}}$    The exercise appears in an chapter that introduces the notion of opposite categories and duality proofs.     My intuition of why the statement is true comes from the following observation:  Let $x,y$ be objects in $\mathbf{C}$ (or equivalently $\mathbf{C}^{\text{op}}$). Let $g^{\text{op}} : c \to y$ and $f^{\text{op}} : c \to x$ be objects in $c/(\mathbf{C}^{\text{op}})$. By the definition of slice category, there exists a morphism $h^{\text{op}} : y \to x$ in $\mathbf{C}^{\text{op}}$ such that the diagram below commutes:  $\hskip2in$   Now the 'corresponding diagram' in the opposite category $(c/(\mathbf{C}^{\text{op}}))^{\text{op}}$ would be:  $\hskip2in$    which, as I understand it, would also be commutative. Now, to me, this indicates:   that the objects in $(c/(\mathbf{C}^{\text{op}}))^{\text{op}}$ are the same as the objects in $\mathbf{C}/c$, namely, a morphism in $\mathbf{C}$ from an object $z \in \mathbf{C}$ to $c$. the commutativity of the seconds diagram describes morphisms $h$ in both $\mathbf{C}/c$ and $(c/(\mathbf{C}^{\text{op}}))^{\text{op}}$ if you reverse the arrows again you return to the same diagram. This makes me think you could construct a map between morphisms by first making a map from $ \mathbf{C}/c \to (\mathbf{C}/c)^{\text{op}} ( \cong c/(\mathbf{C}^{\text{op}}) )$ by $h \mapsto h^{op}$     Now, what I am really looking for is a way to structure a proof. I feel like I have some intuition but am very unsure of how to write it down in a concise way. I am new to category theory so I'm still very much learning how to construct these types of proofs using duality; I feel like what I have written is maybe overkill but I'm trying to be as explicit as possible to make sure I understand everything.  In particular, I don't know how I would get a concrete correspondence between morphisms in the two categories that respects associativity of composition etc.  Any help or pointers would be appreciated! English questions and negation with *do* in syntax I've started putting into practice the answer to . Yet I would like to change this so that there are brackets around the citations:   in the superscript in text,     in the superscript in footnote,  in the bibliography.   I've managed to get the first one and the last one working. The second one however, I don't know how to do this.   Note that I mainly write in english and in dutch, so I don't think there is much babel interference.  Also, would there be a way to order the footnotes so that first all ''normal'' \footnote{} are printed and below that all \sfcite{} citational footnotes (per page that is)?  Here's what I've managed to concoct:  \documentclass{article} \usepackage[english]{babel} \usepackage[pdfborder={0 0 0}]{hyperref} \usepackage[citestyle=numeric-comp,sorting=none,hyperref]{biblatex} \usepackage{filecontents}  % No brackets around the number of each bibliography entry \DeclareFieldFormat{labelnumberwidth}{\textbf{[#1]}}  %--------------------------------------------------------------- % Essentially verbatim from Joseph Wright % http://www.texdev.net/2010/03/08/biblatex-numbered-citations-as-footnotes/ \makeatletter \ExecuteBibliographyOptions{citetracker,sorting=none}  \DeclareCiteCommand{\notefullcite}[\mkbibbrackets]     {\usebibmacro{cite:init}%         \usebibmacro{prenote}}     {\usebibmacro{citeindex}%         \usebibmacro{notefullcite}%         \usebibmacro{cite:comp}}     {}     {\usebibmacro{cite:dump}%         \usebibmacro{postnote}}  \newbibmacro*{notefullcite}{%     \ifciteseen         {}         {\footnotetext[\thefield{labelnumber}]{%             \usedriver{}{\thefield{entrytype}}\addperiod}}}  \DeclareCiteCommand{\sfcite}[\cbx@superscript]%     {\usebibmacro{cite:init}%         \let\multicitedelim=\supercitedelim         \iffieldundef{prenote}         {}         {\BibliographyWarning{Ignoring prenote argument}}%     \iffieldundef{postnote}         {}         {\BibliographyWarning{Ignoring postnote argument}}}     {\usebibmacro{citeindex}%         \usebibmacro{sfcite}%         \usebibmacro{cite:comp}}     {}     {\usebibmacro{cite:dump}}  \newbibmacro*{sfcite}{%     \ifciteseen         {}         {\xappto\cbx@citehook{%             \noexpand\footnotetext[\thefield{labelnumber}]{%             \fullcite{\thefield{entrykey}}\addperiod}}}}  \newrobustcmd{\cbx@superscript}[1]{%     \mkbibsuperscript{[#1]}%     \cbx@citehook     \global\let\cbx@citehook=\empty} \let\cbx@citehook=\empty \makeatother %---------------------------------------------------------------  \begin{filecontents}{\jobname.bib} @article{ref1,     hyphenation = {american},     title = {Natural Products as Sources of New Drugs over the Last 25 Years},     author = {Newman, D.J. and Cragg, G.M.},     journal = {J. of Nat. Prod.},     volume = {70},     number = {3},     pages = {461--477},     year = {2007}} @article{ref2,     hyphenation = {american},     title = {Natural products as leads to potential drugs: an old process or the new hope for drug discovery?},     author = {Newman, D.J.},     journal = {J. of Med. Chem.},     volume = {51},     number = {9},     pages = {2589--2599},     year = {2008}} @online{ref3,     author = {Quintin, C.},     title = {Les eponges},     url = {http://christophe.quintin.pagesperso-orange.fr/Liste_Doc.html},     urldate = {2009-05-03} } \end{filecontents}  \addbibresource{\jobname.bib}  \begin{document} First citation.\sfcite{ref1,ref2} Some text\footnote{A footnote}.   \pagebreak Second citation\sfcite{ref1}, second citation\sfcite{ref2}, first citation.\sfcite{ref3} \printbibliography \end{document} Execute command in remote active terminal Suppose you have a terminal emulator (T1) open with a PID of 6350.  From another terminal, type this command (C1):  echo "ls\n" &gt; /proc/6350/fd/0   This writes ls and the new line in T1 but does not execute it. Why?  I also tried using cat|bash with echo "ls\n" &gt; /proc/catid/fd/0 but it is still not executed.  How can I echo the command into another terminal and have the command executed?  possible answer :  $ mkfifo toto; $ bash &lt; toto; $ echo "ls" &gt; toto;   In this case you cannot write anymore directly in the terminal (everything is displayed the same way the command (C1) displayed thing in this terminal. Order a MySQL table by two columns How do I sort a MySQL table by two columns? What I want are articles sorted by highest ratings first, then most recent date.  As an example, this would be a sample output (left # is the rating, then the article title, then the article date)  +================+=============================+==============+ | article_rating | article                     | article_time | +================+=============================+==============+ | 50             | This article rocks          | Feb 4, 2009  | +----------------+-----------------------------+--------------+ | 35             | This article is pretty good | Feb 1, 2009  | +----------------+-----------------------------+--------------+ | 5              | This Article isn't so hot   | Jan 25, 2009 | +================+=============================+==============+  The relevant SQL I'm using is: ORDER BY article_rating, article_time DESC  I can sort by one or the other, but not both. What are the meaning and possible origin of "word!" and "word up"? How to construct an example of a probability distribution for which $\mathbb{E}\left(\frac{1}{X}\right)=\frac{1}{\mathbb{E}(X)}$ holds, assuming $\mathbb{P}(X\ne0)=1$?    The inequality which follows from Jensen's inequality for a positive-valued RV $X$ is like $\mathbb{E}\left(\frac{1}{X}\right)\ge\frac{1}{\mathbb{E}(X)}$ (the reverse inequality if $X&lt;0$). This is because the mapping $x\mapsto\frac{1}{x}$ is convex for $x&gt;0$ and concave for $x&lt;0$. Following the equality condition in Jensen's inequality, I guess the distribution has to be degenerate for the required equality to hold. A trivial case where the equality holds is of course if $X=1$ a.e. Here is an example I found in a problem book: Consider a discrete random variable $X$ such that $\mathbb{P}(X=-1)=\frac{1}{9}, \mathbb{P}(X=\frac{1}{2})=\mathbb{P}(X=2)=\frac{4}{9}$. It is then easily verified that $\mathbb{E}\left(\frac{1}{X}\right)=\frac{1}{\mathbb{E}(X)}=1$.   This example shows that $X$ need not be positive (or negative) a.e. for the equality in the title to hold. The distribution here is not degenerate either.  How do I construct an example, possibly like the one I found in the book? Is there any motivation? Why does my iPad keep asking for my iCloud password? I keep receiving an iCloud pop-up message to insert my iCloud password every time i switch on my iPad and I'm unable to do anything on it, inserting the password doesn't help. What should I do? Current in wire + moving charge next to wire creates magnetic force in the stationary reference frame OR electric force in the moving reference frame from special relativity due to change in charge density etc.... I think I understand this and I think it's super cool. Now here's the rub...  Current in wire + stationary charge next to wire creates no net charge. This is how nature behaves. I get it. My question is why can't I use the same special relativity logic as above, that is, current in wire cause electrons in wire to contract in accordance with special relativity so there has to be a net charge on the wire, which then acts on stationary charge next to wire.  I have been reading and reading and reading and I have come up with the following:  (1) When electrons in wire get accelerated to create current the distance between them actually expands in accordance with special relativity - something to do with bells spaceship paradox - which I am not going to pretend to understand  (2) This expansion from (1) above is exactly opposite and equal in magnitude to the contraction special relativity then causes and the expansion and contraction cancel out to keep the charge density in the wire constant and therefore no net charge on the wire  Here are my questions:  Is the explanation above correct? If so, please elaborate because i dont understand  If not correct, what is going on?  This is driving me absolutely nuts. Why doesn't my systemd user unit start at boot? Alternating sum of binomial coefficients multiplied by (1/k+1) I'm trying to prove that  $$\sum_{k=0}^n {n \choose k} (-1)^k \frac{1}{k+1} = \frac{1}{n+1}$$  So far I've tried induction (which doesn't really work at all), using well known facts such as  $$\sum_{k=0}^n {n \choose k} (-1)^k = 0$$  and trying to apply identities like  $${n \choose k} = {n-1 \choose k-1} + {n-1 \choose k}$$  Would anyone be able to point me towards the right method? Should I be looking to apply an identity or is there a method I'm missing? My laptop which had Windows 7 on it crashed today. Being unable to access any file kept within, I found about the LiveCD. So I created a LiveUSB with Ubuntu in it, and managed to access my Windows desktop. I'm now backing up files important to me, but I have a question:  Now I'm cutting and pasting the files I want to save, using Ubuntu. Are these files being moved in Windows as well, or do the alterations I make through Ubuntu not affect the Windows state?   So let's say,if I cut and paste all of the D drive, and then format C and reboot with Windows, would the files in D have been gone (since they were cut and not copied) or still be there?  Thanks. I've noticed something while trying to prove the properties of parallel lines, and the properties that a triangle has 180 degrees. To prove the properties of parallel lines, such as alternate angles, you need to use the property that a triangle has 180 degrees. To prove a triangle has 180 degrees however, you need to use the properties of parallel lines. This really bothers me because of how circular it is. They are both reliant on each other to be true, and do not logically show, without being reliant on each other, why triangles have 180 degrees, and why parallel line properties are true.   So what I hoping for here is a way to prove parallel line properties without using the fact that a triangle has 180 degrees, or a way to prove triangles have 180 degrees without using parallel line properties. This way, things will be logical to me, and make sense.   Thanks in advance. Use a specific forwarded key from SSH-agent? Let's say I have a key for Github, along with other keys. I've added lots of keys to my ssh agent (ssh-add -L returns lots of lines) at my home computer A. In my .ssh/config I have set up which key to use with which host, so e.g.  ssh -T -vvv git@github.com 2&gt;&amp;1 | grep Offering   gives  debug1: Offering RSA public key: /Users/doxna/.ssh/id_rsa.github   Only one key is offered, as expected. But then ssh-ing to some host B with ForwardAgent yes and repeating the same command, I get  debug1: Offering RSA public key: /Users/doxna/.ssh/id_rsa.linode2 debug1: Offering RSA public key: /Users/doxna/.ssh/id_rsa.helium debug1: Offering RSA public key: /Users/doxna/.ssh/id_rsa.github   meaning it tries all my keys. This is problematic since only a limited number of keys can be tried before servers return Too many authentication failures. So I tried editing .ssh/config on host B to include  Host github.com   IdentityFile /Users/doxna/.ssh/id_rsa.github   IdentitiesOnly yes   but then I get no key offerings, but rather  debug2: key: /Users/doxna/.ssh/id_rsa.github ((nil))   which I guess means that the key was not found(?) And after all, the key is located at my home computer A, not host B, so the question is how to refer to it at host B? Hope I managed to explain the question.