Getting a apt-error
What can I do if a repository/PPA does not have a Release file?
During my upcoming holiday to the USA I'm thinking about buying a new guitar as the exchange rate is extremely favorable. Excuse my naivety but I have never flown with a guitar before. What is a recommended way to go about this? Could I take it as carry on luggage or would it have to be checked? If checked luggage what kind of precautions should I take to keep it safe? Are there any problems with flying US budget carriers? If I do buy the guitar I'm expecting to have to make two flights with it, one domestic flight with Virgin America and an international flight with Air NZ. Is it acceptable to take photos of slides at a conferences for private use? Is it accepted/appropriate to take pictures of presentation slides at conferences for private use?   I am not talking about putting those pictures out in the public afterwards, I know this is illegal without consent of the presenter.    Should it matter, I am talking about math conferences.  And I am asking because I don't see anyone taking pictures. I'm new to this website. I've checked the other topics and couldn't find the answer to my question. I've also tried to find the result with TI-CAS but the only thing it does is simplify the inequality which really doesn't help at all.  the equation is : $1000n^3 &lt; 2^n$ Now I've been trying to use log but it gets me nowhere (I haven't seen this form before), the answer is supposed to be 24 but I'm not sure. So my question is how to solve step by step this inequality for n. Could you guys help me with this one? Full width image in beamer? While modeling an Audi R8 I have the following problem. The thing I want to create is seen in this image:    I want to create a sharp crease (outlined in red) which starts around the first exhaust and then goes to the second.  Is there an efficient way to do this (I also use the Subdivision Surface Modifier for this model). What is the difference between standard i386 download and the amd64 download of Ubuntu 11.04? I am currently running the i386 on an amd machine, would my system work better with the amd64 download instead? (my machine was running Windows 7 64bit, but I neglected to look at that prior to installing Ubuntu). Reflectivity of a glowing-hot metal surface When a polished piece of metal (or steel in particular) is heated to incandescence, how do its reflective properties change?  Given a mirror-like surface, would the object temporarily cease to act like a mirror at a certain temperature?  Would the specular reflection of light turn into diffuse reflection; in other words, would the surface temporarily become matte/dull?  I am not asking about permanent changes to the object such as melting, but rather can there be a temporary change in the reflectivity only while the the object is hot, that disappears when the object is cooled down?  Background of the question: I have a laser scanner that usually has trouble scanning shiny surfaces with high specular/ low diffuse reflectivity; and it seems to work a lot better for hot steel pieces than for cold ones. Glowing steel also looks less shiny to me than cold steel, but of course that is hard to tell with all the glowing Can't update drupal core to 7.27 Why I can't escape spaces on a bash script? I'm trying to escape the space char for a path in Bash, but neither using a  or  works.  .sh script:  ROOT="/home/hogar/Documents/files/" FILE=${ROOT}"bdd.encrypted" DESTINATION="/home/hogar/Ubuntu\ One/folder"  mv ${FILE} ${DESTINATION}   After execute the script (./file) this is the result:  mv: target 'One/folder' is not a directory   Why does the mv command split the string, and how do I stop this from happening? What regular expression will match valid international phone numbers? How do you interpret a significant but weak correlation? I am a little bit confused about the Area Under Curve (AUC) of ROC and the overall accuracy.  Will the AUC be proportional to the overall accuracy? In other words, when we have a larger overall accuracy will we definitely a get larger AUC? Or are they by definition positively correlated?  If they are positively correlated, why do we bother reporting both of them in some publications?  In real case, I performed some classification task and got the results as follows: classifier A got an accuracy 85% and AUC of 0.98 and classifier B got an accuracy of 93% and AUC of 0.92. Question is, which classifier is better? Is it possible to get results similar to these (or do my results indicate a bug in my implementation)? I've seen $d(xy) = y(dx) + x(dy)$, but I don't understand the principle behind it and memorizing it is lame.  Can anyone explain what is going on here?  For example from physics, $$F = {{dP} \over {dt}}$$ $$F = {{d(mv)} \over {dt}}$$ $$F = {{v(dm) + m(dv)} \over {dt}}$$ Since $$dm = 0$$  $$F = {{m(dv)} \over {dt}}$$ Since $$a = {{dv} \over {dt}}$$ $$F = ma$$ Show OPs if someone is answering, live I ask a lot of question on SO, so this recommendation/idea comes from that experience. I'm not really sure how this would fit in with the current structure of SE.   Oftentimes after asking a question, maybe after an hour or so, I end up finding the answer I needed somewhere. And it comes time for me to answer the most difficult question of all: do I delete this question, or do I keep it in case someone answers and others may benefit from it. The problem is, if I don't delete it and no one answers, my acceptance rate goes down. So usually I'll just delete it.  However, sometimes I fear that someone is typing a really really long answer to my question since itäs only been an hour, and so I imagine the nightmare that person experiences when they find out their essay will be gone to waste. Overall, this never-to-be-seen-again answer could have benefitted many people had the question remained.  Since SE has gone "live-happy" lately, where answers and comments refresh live, I thought it might be interesting if the original asker of the question (or anyone else for that matter) could see how many people are currently responding to the question (just count, not necessary to display their names). This way, if I know someone is replying, I won't delete the question, and others can benefit from it. Making dual power supply from single for opamp? For the circuit of opamp 741. we have to supply the dual power for it. How can I make a dual power supply from single. For example, make a (+9V)-GND-(-9V) from single 9V battery ? How to concatenate a std::string and an int I thought this would be really simple, but it's presenting some difficulties. If I have std::string name = &quot;John&quot;; int age = 21;  How do I combine them to get a single string &quot;John21&quot;? The most obvious answer everyone over the Internet is giving to this question is "Because anime is produced much faster compared to manga, they need to put in fillers in order to slow down the anime series". However, that shouldn't be the only reason.  For example, consider One Piece. The show is going on for more than 500 episodes, and less than 10% are fillers. Comparing that to Naruto, the show has almost the same number of episodes (original and Shippuuden combined), but almost 50% of its episodes are fillers. Needless to say, the manga of Naruto is so far ahead that the anime won't be able to catch up even if they produce 100+ episodes without any fillers. QTimer can only be used with threads started with QThread resizable serial console window? When using the serial console of my system I always end up with $COLUMNS=80 and $LINES=24.  While I can change these variables manually it is somewhat annoying to do this any time when the client side terminal window has been resized.  Usually I'm connecting to the console using screen /dev/mytty baudrate.  Changing the $TERM environment variable to "screen" or "xterm" does not help.  Will I need to call getty with some of those instead of vt100?  Needless to say that all of this works fine, when I connect to the same machine using ssh. siunitx tabular numbers with separated uncertainty I would like to format the space reserved for a number shown in a table with separated uncertainty. It seems that when I use the table-format option the brackets around the mantissa disappear. This is illustrated in the example below:  \documentclass{article}     \usepackage{siunitx}  \begin{document}     \begin{table}   \begin{tabular}{                   S[separate-uncertainty = true]                   S[table-format=1.1(1)e1,                   separate-uncertainty = true]                   }     {Header} &amp; {Header}\\     1.0(2)e2 &amp; 1.0(2)e2\\   \end{tabular} \end{table}     \end{document}     I have also tried to use the bracket-numbers and multi-part-units = brackets without solving this issue. Is there any workaround to center the number and keep the brackets like in the first column of the example?