Could you explain the usage of it in the following sentences?   I don't like it  when you speak like this. I hate it when you speak like this. I know it for certain that he is in town now. He owes it to his brother that he became a research chemist.
I wanted to leave the question title as is so as not to take away from my amusement :).  Anyway,     It's raining.   What is raining? Is it the sky? The clouds? The weather? The rain? What is "it"? Any historical insights on the statement?
How to convert ISO 8601 date (string) to Date? Setting a document in MS Word-12pt (12bp) Warning  If you're looking for advice how to make your document look like it's been written in Word, this is most likely not the question you're looking for. This question is mostly of theoretical nature, as it results in tiny differences, which will most likely not be noticed by someone who doesn't allow the use of LaTeX.  Questions that might be more helpful for this matter are:           Question  I learned that MS Word uses a slightly different version of the unit "point" (pt) than TeX does:     The 12 point of Word will be PostScript point, which in TeX would be called 12bp. A TeX pt is slightly smaller: it's 1/72.27 inch, while a bp/PostScript point is 1/72 inch. See also    ( in )  I'm writing a paper that would usually be expected to be "typeset" in MS Word, thus I want to use the same font size as Word would.  How do I set a document e.g. in the "12pt" font size that MS Word would use?  In case it matters, I'm using the article document class, Latin Modern (lmodern) as a font with the T1 font encoding and compile with pdfLaTeX, but input on different set-ups is more than welcome. Force alt + tab to switch only on current workspace in GNOME shell Energy momentum tensor from Noether's theorem in the book Quantum Field Theory by Itzykson and Zuber the following derivation for the stress-energy tensor is proposed (p.22):  Assume a Lagrangian density depending on the spacetime coordinates $x$ only through fields and their gradients. Under a translation we have $$\mathcal L (x+a)=\mathcal L[\phi_i(x+a),\partial_\mu\phi_i(x+a)].$$  Consider an infinitesimal $x$-dependent transformation $$\delta\phi_i=\delta a^\mu(x)\partial_\mu\phi_i(x),$$ $$\delta\partial_u\phi_i(x)=\delta a^\nu \partial_\nu\partial_\mu\phi_i(x)+\partial_\mu[\delta a^\nu (x)]\partial_\nu \phi_i(x).$$  The proof then proceeds with variation of the action and integration by parts. But why do we consider an $x$-dependent local transformation instead of a global transformation? What are your tips for improving overall system performance on ubuntu? Inspired by this  I realized that some default settings may be rather conservative on Ubuntu and that it's possible to tweak it with little or no risk if you wish to make it faster.  This is not meant to be application specific (e.g. make firefox load pages faster), but system wide.  Preferably 1 tip per answer, with enough detail for people to implement it.  A couple of mine would be:   Install  (via Software Center or sudo apt-get install preload); Change  value - "which controls the degree to which the kernel prefers to swap when it tries to free memory";   What are yours?  PS: Since this is not intended to have a unique answer but rather, several useful tips, I'm making this community wiki out-of-the-box. Euclidean distance vs Squared Show that not all 5 cycles in $A_5$ are conjugate in $A_5$ This is a practice question (not assignment). One thing I am wondering is what this question exactly means. From my understanding, the conjugate of $a \in A_5$ is $gag^{-1} \in A_5$ where $g \in A_5$. I was trying to look at a similar question here on MSE and someone mentioned $(12345) \in A_5$ is not conjuagte in $A_5$. So does that means there exists a $g \in A_5$ such that $g(12345)g^{-1} \notin A_5$ (I am guessing this is incorrect since $A_5$ is a group). I am also away of the property that $g(12345)g^{-1} = (g(1)g(2)g(3)g(4)g(5))$. Bibliography style elsarticle-num-names with DOI and hyperlinks but no explicit url I prepared my article with elsarticle, using \citep &amp; \citet throughout. I originally used apalike bibliographystyle but now need to change it to elsarticle-num-names for citation formatting requirements (see point #2 below).  Now, I am attempting to make 2 changes:     add DOIs to the bibliography change reference style to [1] for \citep and Author et al. [1] for \citet.   I want to keep hyperref and do not want explicit URLs (only DOIs) but cannot make this work!  Thank you for any help you might have!  MWE:  \documentclass[preprint,12pt]{elsarticle} %\usepackage{hyperref}  \journal{Test Journal} \begin{document} \begin{frontmatter} \title{The Title} \author{Prof. Big Ol' Wanker} \address{123 Happy Lane} \begin{abstract} TEXT \end{abstract} \begin{keyword} keyword 1 \sep keyword 2 \sep keyword 3 \end{keyword} \end{frontmatter}  \section{SECTION1TEST} \noindent cite: \cite{Richards1931} \\ citep: \citep{Richards1931} \\ citet: \citet{Richards1931} \\  \bibliography{library} \bibliographystyle{elsarticle-num-names}  \end{document}   Here is the reference for Richards1931 from my library.bib file:    @article{Richards1931, author = {Richards, LA}, doi = {10.1063/1.1745010}, file = {:D$\backslash$:/Papers/Richards - 1931 - Capillary Conduction of Liquids Through Porous Mediums - Journal of Applied Physics.pdf:pdf}, issn = {01486349}, journal = {Journal of Applied Physics}, pages = {318}, title = {{Capillary Conduction of Liquids Through Porous Mediums}}, url = {http://scitation.aip.org/content/aip/journal/jap/1/5/10.1063/1.1745010}, volume = {1}, year = {1931} }   without hyperref (wanted hyperlinks present, DOI displays correctly, but unwanted URL is present):    with hyperref (hyperlinks not present, DOI displays incorrectly, and unwanted URL is present): Show that $[0, 1)\times[0, 1)$ is homeomorphic to $[0, 1]\times[0, 1)$ but not to $[0, 1]\times[0, 1]$. When I sketch these spaces it this statement makes sense intuitively because $[0, 1]\times[0, 1]$ is closed and $[0, 1)\times[0, 1)$ and $[0, 1]\times[0, 1)$ are each "missing" part of their boundary which would make them closed. I also know, $[0, 1]\times[0, 1]$ is compact and compact spaces are not homeomorphic to non-compact spaces.   I am having trouble saying this explicitly, as is pretty obvious in the clumsiness of the wording above. Is there a correct resistance value for I2C pull-up resistors? Is it possible to add images to comments? I was wondering if it is possible to post a comment with an image.  Recently, during a question about data-visualization in Cross Validated, there was a controversy about using one type of chart for another.   I had posted a question about pie-charts, after reading some references I decided to build an example and clarify the point of using waffle-chart vs pie-chart. In a way, my example was not an answer it was more properly a comment on waffle-charts. But it seems to be impossible to post a comment with an image (Maybe, there is a way but I can't figure out how).  I don't know if it is relevant to post images in comments in other SO sites. So, if there is no way to post images in comments... why not making it possible? And if there is a way to post an image with a comment, how I can do it? Is a capacitor in an open circuit charged? Say I have a circuit consisting of a battery, a wire, an open switch, and a capacitor. The circuit is open since the switch is open.  My book says that the capacitor will only be charged when the switch is closed, but I don't see why this is true. I would expect the capacitor to be charged a little - not as much as if the circuit is closed, but still charged none the less.  To further illustrate my point consider this: If the circuit is open, the current must be zero. Consequently the field must be zero. For the field to be zero, the capacitor's field must cancel out the battery's field. Therefore the capacitor must be charged.  Generalizing this concept, shouldn't capacitors be charged (to a lesser degree) in open circuits?  EDIT: In other words, if the field is zero, the capacitor must be charged to cancel out the field of the battery. How to prove that $\sum_{r=0}^n\binom{n}{r}2^r=3^n$ What is the difference between class and instance attributes? How do you iterate over each file in a directory with a .bat or .cmd file?  For simplicity please provide an answer that just echoes the filename or file path. Is it possible to use more than 20 layers? Is it possible to use more than 20 Scene layers or Render layers in Blender? Why has it become an industry standard for logos to redirect a user to a website's homepage?   Where was this first seen? I use Lasso logistic regression in order to identify a smaller subset of important variables. I start with N=51 (28/23) and 32 predictors.   So far it looks pretty promising, because I can identify four important predictors in my optimal model.   Now I would like to take those four predictors and examine them along with some control variables in a standard logistic regression.   My question is, does that analysis strategy make sense? Is there a better way to include controls or other variables that might be interesting?  For a better understanding:   Identify important variables via Lasso logistic regression Do further analysis including identified predictors and other control variables using standard logistic regression (using AIC to check model fit) There is a hint to show that if there were points in $\mathbb{Q}$, then there would exist $r,s, t \in \mathbb{Z}$ with $\gcd(r, t) = 1$ such that $2s^2 = t^4 - 17r^4$ , and then show that any prime dividing $s$ is a quadratic residue modulo $17$.  I'm stuck on the first bit - if you suppose $\left(\frac{a}{b}, \frac{c}{d}\right)$ is a point on the curve in $\mathbb{Q}$ (so $a, b, c, d \in \mathbb{Z}$) then you get to $2a^2d^4 = b^2c^4 - 17b^2d^4$, but I'm not sure where to go from here since you don't know that $b$ is a square? I cannot find the Polygon Neighbors tool. I have searched for it as I usually do and I have also browsed the proximity toolset but it is not there. The other Tools, e.g. Buffer and Near are there and work fine. Here is a screenshot: