Towns/cities are surrounded by a kind of swirling &amp; confusing energy storm or field.  In my mind's eye it was blue/purple in color.  The towns/inhabited regions are in bubbles of normal environment.  This fantasy (or perhaps SF) world has special guides able to lead caravans between the towns/cities, without which the caravans would become hopelessly lost.  In one of the books, I think it's revealed that the energy fields between cities can charge people up with (magical?) power.  I think only the guides are able to use this power.  I vaguely associate this story with Roger Zelazny but I can't find anything in his bibliography that looks like this trilogy(?).  These books would have been published no later than the late '80s.
Fantasy/scifi combo - band of travelers who must get from "sphere" or domain to domain - each geographic area is ruled by a magician - it turns out later these are people who are unwittingly tapping into the computer grid they all live on to alter their own reality?
When closing a question as duplicate the &quot;Possible duplicate of&quot; comment is automagically added to the question. However when adding such a comment manually: &quot;possible duplicate of random text&quot; that comment is also removed. To me it doesn't make sense that questions which to not point to a SO / SE question or even comments without any links in it are also removed when the question is closed as a dupe. I just found this out by close voting a question as a dupe of another question, but I also added a manual comment which linked to a user profile (because it contains lots of relevant information for OP and possible future reasons): possible duplicate of this [user](http://stackoverflow.com/users/727208/teresko?tab=answers&amp;sort=votes)'s list.  By the looks of it the script simply checks whether the comment starts with &quot;possible duplicate of&quot; and if it matches it will be removed. The  team also did a quick test with a very simple example which also got thrown away: possible duplicate of testing........  I understand that this issue is minor and there might as well be a technical reason for this (i.e. not having to keep track of automatic vs manual comments), but this behavior is kinda odd to me. I can think of two solutions for this:  keep track of manually vs automagically added dupe comments (again you SO people might have a good reason to not want this). Improve the &quot;dupe comment matcher ™&quot; to at least check whether the comment is in the correct format for &quot;auto dupe comments ™&quot; with a proper link to a question page. Upvoting a downvoted answer will do +2 upvote? I have first downvoted an answer. Then, I decided to leave it the way it was before, meaning to undo my downvote just like it never existed, so I upvote to remove my downvote. Suprise! SO seems to consider it as two upvotes!  Let's say I have an answer with -3, then I decide to downvote it making it -4. After deeper thoughts, I prefer to remove my downvote to let it the way it was before I downvoted, meaning -3, but SO makes it -2 automatically!     Wouldn't it be supposed -3, and not -2? If someone else would have upvoted, it would have made it an upvote +1, not a +2!   Am I missing something here?  In fact, is there a way to tell SO that I only wish to undo my downvote, and not upvote the answer? I may understand why it does behave this way. I only wish to undo my downvote, though. What happens if my ESTA expires on the day of arrival? I'm French and will travel the 14th of June to the US. My ESTA expires the 14th of  June 2013 and I'm wondering if my ESTA will be valid when I'll land in the US on the 14th of June 2013.  Does someone know anything about that? I am using Google Chrome. I re-installed it today as it was crashing when I start it. I guess may be that this was due to any of my Extensions or Google Update. I disabled my extensions but it was still crashing. Now I installed an old version of chrome from . However, Chrome automaticallyuppdates itself (although Windows asks me before installing and I don't grant it permissions, its still annoying to get Google update asking me permission after a couple of minutes.   I saw the question at  however, it doesn't seem to hlp me. i disabled the service and I stopped it as well, but the problem still persists. I also tried to look into the registry according to the following link:  but the "Policies" section of my registry doesn't contain any folder called "Google". I use Windows 7 - 64 bit Home Premium Service pack 1.  Could anybody help? Thanks a ton! Does a photon having superimposed frequencies exist?  (wrt frequency detected by prism or other detectors, not wrt human eye as only rod-cells can detect one photon falling in the detectable (visible) frequency band and the single photon is perceived by eye+brain as grey irrespective of frequency).  Also, with white here, I do not wish to restrict the question implying all VIBGYOR frequencies or only RGB as each color is also a range of frequencies and white to trichromatic-sensor human eye is just output from three frequencies RGB.  Or can it be that materials which slow light down cause a photon of some single frequency and higher energy to split into VIBGYOR? || and the entire spectrum of human eye's detection range is VIBGYOR+W (as monochromatic light of high intensity can also be perceived white by human eye and it is not related to individual color sensors of human eye at all but that above a certain energy per unit volume (referring to detector area of eye cells), we perceive it white, (somewhat but not exactly) similar to combination of red and green which human eye+brain calls yellow.  I have added the additional description to make the question more precise. If my description causes confusion, please stay with the original question and use description just to get an idea of the intent of the question. Convert a router to a switch? I was using the amspset document class for generating exam practice problems. I had wanted to add some referencing to the problems so I started a new counter like this (adapted from some Tex Exchange post)  \newcounter{P} \newcommand{\plb}[1]{\refstepcounter{P}\label{#1} \textbf{P-\ref{#1}.}}  \begin{problem} \plb{p1} A parallel-wire transmission line is constructed of \#6 AWG copper wire (diameter $d=0.162$ in., conductivity $\sigma_c=5.8\times 10^7$ S/m) with a 12-inch separation in air. Assuming no leakage between the two wires, find $R'$, $L'$, $G'$, and $C'$. Assume a working frequency of 1 MHz. \end{problem}  \begin{solution} Using Table.~\ref{tab:tlparam} and Fig.~\ref{fig:tlempl},  \[ Rs = \sqrt{\pi f \mu_c/\sigma_c} = 2.61\times10^{-4}~ \Omega\] \[ R' = \frac{2R_s}{\pi d} = 4.04\times10^{-2} ~\Omega\text{/m} \] \[ L' = \frac{\mu_0}{\pi} \ln{\frac{2D}{d}}=2.0~\mu \text{H/m} \] \[ C' = \frac{\pi \epsilon}{\displaystyle\ln{\frac{2D}{d}}}=5.56 ~\text{pF/m} \] $G'=0$ because the problem states that there is no leakage between the two wires. \end{solution}  \begin{figure}[ht] \begin{centering}     \includegraphics{fig24}     \caption{(Fig.2-4 from FAE) A few examples of transmission lines.} \end{centering} \label{fig:tlempl} \end{figure}  \begin{table}[ht] \caption{(Table 2-1 from FAE)Transmission-line parameters $R'$, $L'$, $G'$, and $C'$ for three types of lines.}     \begin{tabular}{c}         \hspace{3cm}\includegraphics{tb21}     \end{tabular} \label{tab:tlparam} \end{table} ... and more   Now all the figure references stop working, I get "Fig. " instead of "Fig. 1". The table references are alright though. Any idea what the problem could be? Probability of a player winning before another Given a 7 sided dice, 2 players roll it independantly simultaneously and when a player rolls a '6' he gets a prize.  What is the probability of the first player getting a prize before the second?  So my solution is to sum over all the turns j in which player 1 could win, and make the second player lose all these turns:  $$P(A) = \sum_{i=1}^{\infty}(6/7)^{j-1}*(1/7)*(6/7)^j = 0.461$$ My question is if my solution is correct, and if so, why is the probability so low? It seems to me that either player 1 wins before the 2nd or the other way around, and the probability of them playing forever is 0, so it should be 0.5? Basic If/Then in Python Parser of ArcGIS Field Calculator? One can show that $\mathbb{P}^n\times \mathbb{P}^m$ is birational to $\mathbb{P}^{n+m}$ by making note of the Zariski topologies and the canonical isomorphism between affine spaces $\mathbb{A}^n\times \mathbb{A}^m\to \mathbb{A}^{n+m}$.   Question: Does it follow that there is isomorphism $\mathbb{P}^n\times \mathbb{P}^m\to \mathbb{P}^{n+m}$? If so, what is an example of such an isomorphism?   Unfortunately I am having a hard time coming up with one, and haven't seen too many examples thus far. Xerces error: org.apache.xerces.impl.dv.dtd.DTDDVFactoryImpl Rename a file to parent directory's name in terminal I have to deal with a large number of files nested inside of directories (one file per directory), resembling something like this:  fred/result.txt john/result.txt mary/result.txt ...   I am currently using the following command to process each of those files:  find . -maxdepth 1 -type d \( ! -name . \) -exec bash -c \"cd '{}' &amp;&amp; processResult result.txt\" \;   I am looking for something I can add into the end of this command that will change the filenames to fred.txt, etc. and then later move the file into the parent directory to eliminate the extra layer of directories.  What would be the best way to do this? "He didn't know where New Jersey was" I know the past tense carries the past tense in every dependent clause, but referring specifically to places or to things that are eternal, like the Earth, seems a bit weird and therefore we sometimes (I believe incorrectly) say     He didn't know that New Jersey was actually on the East Coast.   Because it still is. Or     He thought the Earth was round.   So is it square now?  Logically speaking, would you consider the use of past tense here a bit confusing in a day-to-day speech in these examples? Would you instinctively opt for using the present tense? How do I create a very long delay with Redstone? The only things I've found so far are a cart method (which ceased working in 1.6), a dispenser method (utilizing the decay on dropped items, but this requires occasional feeding), and a binary counter (which won't work for a single input but rather a fluctuating one).  I want to have a circuit that when I apply an input signal, the output signal doesn't change for 2 to 5 minutes.  When the input turns off, I again want a 2 to 5 minute delay.  I could accomplish this with (roughly) 240 to 600 redstone repeaters, but this is far in excess of being useful.  The only method I can think of, but would require a XOR gate (on the button-input and final output) to start and stop a clock attached to a binary counter.  While I can make room for a device of this size, I was hoping for something simpler. Escaped line break tag in tooltip on election page I'm using the beamer miniframes theme (with subsection=false) and the compress option. Currently the navigation shows the dots for each subsection side-by-side. I would prefer if there would be a horizontal space (e.g. with the width of a dot) between the dots of each subsection. Is this possible? Right now it looks like:  Section 1 oooooo  And I would prefer it to look like:  Section 1 ooo ooo  MWE: \documentclass[compress]{beamer}   \useoutertheme[subsection=false]{miniframes}   \begin{document}   \section{Sec 1}   \subsection{}   \begin{frame}[t]     hi   \end{frame} \subsection{}   \begin{frame}[t]     hi   \end{frame} \end{document}` Execute command from file in current shell I want to executed command from file (which is script) in current shell in terminal.  Example: I have file ch_dir contains following:  #!/bin/bash cd /usr   Now if I execute file usually as following then it executes commands in different shell:  pandya@pandya-desktop:~$ ./ch_dir pandya@pandya-desktop:~$   Here cd /user is executed in different shell.  But I want to execute in Current shell. How do I do that?  Note: Here cd is only used to explain. Question's aim is to execute any command in current shell When I sum up the sizes of my files, I get one figure. If I run du, I get another figure. If I run du on all the files on my partition, it doesn't match what df claims is used. Why are there so many different figures for the total size of my files? Can't computers add?  Speaking of adding: when I add the “Used” and “Available” columns of df, I don't get the total figure. And that total figure is smaller than the size of my partition. And if I add up my partition sizes I don't get my disk size! What gives? Sylvester's determinant identity Sylvester's determinant identity states that if $A$ and $B$ are matrices of sizes $m\times n$ and $n\times m$, then   $$ \det(I_m+AB) = \det(I_n+BA)$$   where $I_m$ and $I_n$ denote the $m \times m$ and $n \times n$ identity matrices, respectively.  Could you sketch a proof for me, or point to an accessible reference? Why does change in speed of a wave make it refract? When a light wave enters a medium with a higher refractive index (e.g. from air to standard glass) and its speed decreases, why does that make it refract/bend?  I understand that wavelength decreases and frequency stays the same and therefore its speed decreases, but I can't find anywhere whatsoever why the speed decrease cause the wave to refract. So could someone please explain this?