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Why singularity in a black hole, and not just "very dense"? Why does there have to be a singularity in a black hole, and not just a very dense lump of matter of finite size? If there's any such thing as granularity of space, couldn't the "singularity" be just the smallest possible size? Filling in new field in attribute table based on values of another field in ArcGIS Desktop? I have added a new field (Category) in an attribute table of a shapefile and I would like to fill it with numbers, 0 or 1, based on the numbers of another field (Calorific value) of the same attribute table.   That means that if the Calorific value is higher than 15, then I would like to fill in the corresponding cells of the (new) Category field with 1. If the Calorific value is less than 15, then the rest cells of the (new) Category field to be filled in with the number 0.   Is there a way to do this automatically rather than manually? Allow applications downloaded from anywhere in macOS Sierra In previous versions of the OS in the security pane, you are provided an option of:    But in this version there is no option anywhere:    Is there a way that I can turn on anywhere? (via Terminal maybe?) I have my Xbox One set up to automatically download and install updates, the rest of my settings are shown below:    Is there a reason my games will show an update symbol on their tile, but they still don't download the update until I start the game manually? Apparently, my linux ubuntu setup of QGIS doesn't contain grass gis, although when I initially installed it last week I added grass gis to the command line. Anyway, I typed in once again and installed grass gis 7.0, however while GRASS starts, the plugin QGIS for it doesn't show up. Any ideas? There was the following paragraph in the article that came under the title, “GOP and the rise of Anti-knowledge” written by  (October 29, 2015):     “English unfortunately doesn’t have a precise word for the German   “Fachidiot,” a narrowly specialized person accomplished in his own   field but a blithering idiot outside it. In any case, a surgeon is   basically a skilled auto mechanic who is not bothered by the sight of   blood and palpitating organs. We need the surgeon’s skills on pain of   agonizing death, and reward him commensurately but that does not make   him a Voltaire.”    In Japanese we have a word, 専門バカ, of which literal translation is “specialist idiot” meaning exactly same as defined the above - a narrowly specialized person accomplished in his own field but a blithering idiot outside it.  I’m really curious about the absence of short descriptions of the specialist who knows nothing more than his specialty area in English like German “Fachidiot,” and Japanese "専門バカ."  Isn’t there really any short word counterpart to “Fachidiot,” specialist’s ignorance, for instance, in English?  P.S.  I found "narrow-minded specialisit" as a German-to-English translation of "fachidiot" in the web site, Interglot translation dictionary. How do I customize the context menu in Nautilus? I need a good explanation (references are a plus) on Python's slice notation.   To me, this notation needs a bit of picking up.   It looks extremely powerful, but I haven't quite got my head around it. I'm looking for an easy and robust way to strip all the comments from a listing. My approach (passing \@gobble to the commentstyle key) correctly removes all the one-line comments and block comments. However, the white space left behind by by block comments remains, creating useless gaps in my listing. See the screenshot below (the red rectangle is my emphasis). Any idea?    \documentclass{article}  \usepackage{xcolor} \usepackage[T1]{fontenc} \renewcommand{\ttdefault}{pcr} \usepackage{listings}  \makeatletter \lstset% {%   basicstyle   = \ttfamily,   morecomment  = [l]{//},   morecomment  = [s]{/*}{*/},   frame        = single,   commentstyle = \itshape\color[gray]{.5},   rulecolor    = \color{black},   breaklines, } \makeatother  \usepackage{filecontents} \begin{filecontents*}{sample.c} #include &lt;stdio.h&gt;  /*  block comment taking up white space */ main() {     float fahr, celsius;     float lower, upper, step;     lower   = 0;    /* lower limit of temperature scale */     upper   = 300;  /* upper limit */     step    = 20;   /* step size */     celsius = lower;     printf("\nCelsius\tFahr\n");     while (celsius &lt;= upper)        {         fahr = (9.0/5.0) * celsius+32.0;         printf("%3.0f\t%6.1f\n", celsius, fahr);         celsius = celsius + step;     } } \end{filecontents*}  \begin{document} \makeatletter \lstinputlisting[caption={with comments}]{sample.c} \lstinputlisting[caption={without comments},commentstyle={\@gobble}]{sample.c} \makeatother \end{document} ESTA approved on the same day as B-1/B-2 visa refused I am writing because I have a question regarding my ESTA application and because I could not find a similar case online that would help me at this stage. I have never been to the U.S. so this would be my first visit.    I am a German citizen, hence eligible for the Waiver Program. I applied for an ESTA in June 2014 and got approved. After further research on the Internet I learned that the passport should be valid until 6 months after the planned return date. My passport was due to run out in Feb 2015 - which still should have been fine but because I didn't want to take chances I applied for a new passport which was issued August 2014 and is now valid until August 2024. My passport number has been changed also.    After I received my new passport I was advised by a friend to apply for a B-1/B-2 visa as it would allow me to extend my stay and it seemed like a good idea at first. On the day of my interview I also applied for a new ESTA with my new passport number (just in case) which again was granted.   Unfortunately for me the interview for the B-1/B-2 visa was unsuccessful and I got rejected. I was not aware then that after a rejected interview one could not travel with ESTA, otherwise I would have never risked it!  Now I am very concerned, can I still use my ESTA and enter the U.S.? as I read everywhere that once you get rejected the chances of getting through are very slim and any visa rejection will result in not being able to use the waiver program.  It might be important to note that both the B-1/B-2 interview and the waiver application were on the same day, 21st of August 2014, so depending on how one might look at it that might present a problem too I suppose.  I guess the frustration lies in the fact that I did not need to apply for a B-1/B-2 visa to begin with, and had I not I would now not have these problems. I would like to know how likely it is that I can still travel under the waiver program, if at all, and what my options are at this point. Create a variable in .CSS file for use within that .CSS file Possible Duplicate:          We have some "theme colors" that are reused in our CSS sheet.  Is there a way to set a variable and then reuse it?  E.g.  .css OurColor: Blue  H1 {   color:OurColor; } Squid IP Routing Issue I have a squid server installed with 30 additional proxy addresses. Whenever I try to use one of these proxy addresses with a browser, like chrome, my IP shows as the main server IP as opposed to the additional address. For example, say the home IP is 192.0.0.10 and the additional IP I'm trying to use is 192.0.0.13, when going to a &quot;what is my IP&quot; type of site, it shows 192.0.0.10 no matter what additional address I use. Any idea as to why this might happen? Thanks for any help. proving logical equivalence $(P \leftrightarrow Q) \equiv (P \wedge Q) \vee (\neg P \wedge \neg Q)$ I am currently working through Velleman's book How To Prove It and was asked to prove the following  $(P \leftrightarrow Q) \equiv (P \wedge Q) \vee (\neg P \wedge \neg Q)$  This is my work thus far  $(P \to Q) \wedge (Q \to P)$  $(\neg P \vee Q) \wedge (\neg Q \vee P)$ (since $(P \to Q) \equiv (\neg P \vee Q)$)  $\neg[\neg(\neg P \vee Q) \vee \neg (\neg Q \vee P)]$ (Demorgan's Law)  $\neg [(P \wedge \neg Q) \vee (Q \wedge \neg P)]$ (Demorgan's Law)  At this point I am little unsure how to proceed.   Here are a few things I've tried or considered thus far:  I thought that I could perhaps switch some of the terms in step 3 using the law of associativity however the $\neg$ on the outside of the two terms prevents me from doing so (constructing a truth table for $\neg (\neg P \vee Q) \vee (\neg Q \vee P)$ and $\neg (\neg P \vee \neg Q) \vee \neg (P \vee Q)$ for sanity purposes)  I can't seem to apply the law of distribution since the corresponding terms are negated.  Applying demorgans law to one of the terms individually on step 2 or 3 doesnt seem to get me very far either.  Did I perhaps skip something? Am I even on the right track? Any help is appreciated Logo is slightly misaligned Should you use a plural verb if you refer to a fraction? Is there anyway to remove denied permissions from a group for a folder if I dont have access? Detecting EOF in C++ from a file redirected to STDIN Why is it so hard to find the roots of polynomial equations? The question that follows was inspired by  question:  When trying to solve for the roots of a polynomial equation, the quadratic formula is much more simple than the cubic formula and the cubic formula is much more simple than the quartic formula.    That the general solutions to various polynomial equations are so complex and difficult to derive seems to suggest a fundamental limitation in the problem solving capabilities of the mathematical machinery. Does this intuition of mine make any sense? What should I make of it? Why is it that with each successive degree in a polynomial equation, the solution becomes so much more complex? Can I gain some intuition about what makes finding the roots so hard? According to the : "there is no general algebraic solution—that is, solution in radicals— to polynomial equations of degree five or higher." What is so special about the quintic that makes it the cut-off for finding a general algebraic solution? I'm writing up my dissertation and I'm really confused where to use "the". Examples:     In this experiment, (the?) heat transfer coefficient was calculated, allowing to estimate (the?)frost thickness.    And:     Firstly, (the?) air properties are defined.   And:     As (the?) crystals grow in radius, the amount of air in (the?) ice is reduced, due to (the?) ice becoming more packed.   None of the nouns mentioned above have been used for the first time, so I rule out the use of "a".   Would appreciate any help. How to permanently switch Caps Lock and Esc How can I permanently switch the Caps Lock and Esc key functions in Saucy? I can use this command to do it temporarily (until reboot):  /usr/bin/setxkbmap -option "caps:swapescape"   I tried adding that command as a Startup Application, but it doesn't seem to do anything.