Ubuntu 14.04 freezes after kernel update
How can I boot with an older kernel version?
Can "Mr", "Mrs", etc. be used with a first name? Automatically put PGFPlots xtick scale label in x axis label I'm trying to put xtick scale label (defined by pgfkey /pgfplots/xtick scale label code/.code) in x axis label, between variable name and unit.  I've tried executing using the option xlabel = {$ x $ (\pgfkeysvalueof{/pgfplots/xtick scale label code/.code} m)} to put in but this doesn't work.  I've also tried the following xtick scale label code/.code={\pgfkeyssetvalue{/pgfplots/xlabel}{#1}} to force PGFPlots to change my xlabel but it doesn't work as well.  I know I can do this by hand, but I'm interested in automatic approach. Is there a workaround or a solution to this?  My MWE is:  \documentclass{article} \usepackage{pgfplots} \pgfplotsset{compat=1.14}  \begin{document}      \begin{tikzpicture}     \begin{axis}[         scaled x ticks=true,         scaled y ticks = false,         y tick label style={/pgf/number format/fixed},         %xtick scale label code/.code={\pgfkeyssetvalue{/pgfplots/xlabel}{#1}},         xlabel = {$ x $ (\pgfkeysvalueof{/pgfplots/xtick scale label code/.code} m)},         ylabel = {$ y $},     ]      \addplot[line width=3pt] coordinates {(0.0,0.0)(100,1)(400,2)(10000,0)};      \end{axis}     \end{tikzpicture}  \end{document}   Output from this code is: Command "find -name" must be enclosed in quotes or it doesn't work. Why is that? find . -name *.rb   doesn't work on my ubuntu  I have to do  find . -name "*.rb"   to get it to work.  Why is that? Why do statisticians like "$n-1$" instead of "$n$"? Fade in action applicable to all objects (in cycles) I am trying to make a schematic video about assembling a machine. For a lot of objects (bolts, etc...) I use the same delta location action, so they get assembled in their position. This allows me to use the NLA editor, to make almost all the animations.  The problem is when I try to fade in &amp; fade out objects. Loc, rot &amp; scale works well, because all objects share these properties. But transparency depends on the material.  I've tried to have all materials end with a mix node connected to a transparent shader. So with the 'Fac' slider I can animate the fade. But the result action can't be shared between different objects, as they have different materials.   So, is there any visibility property of object I can animate? This would be great for motion graphics too.  Thanks What is the VC dimension of a decision tree? What is the  of a decision tree with k splits in two dimensions? Let us say the model is CART and the only allowed splits are parallel to the axes.  So for one split we can  and then for any labeling of the points we could get perfect prediction (i.e.: shattered points)  But what about 2 splits, or any general k? When (and why) should you take the log of a distribution (of numbers)? iPhoto had it's own trash, and when you've emptied it, files moved to the system trash. I cannot find this in the new Photos app. When I delete files, they don't appear in the system trash. Firstly, how do you gain the score exactly? I know it shows in the bar on the side of the map, but I remember a match where I was lone-wolfing and still got a pretty high score in that bar. I suppose my other squad members were together, but do I also gain for their work?  Also, does the score reset when I start a new game? I mean, I play support with the Offensive perk and it took me a long game of conquest to just unlock lvl-3 extra grenade. In the next match, that 'nade is gone. Don't I keep it forever? My website title shows up slightly different from what's in my title tag, only in Google search What is the word or term used to describe doing an activity or work with a high level of concentration and intention, trying your best? I installed Fedora 15 on my laptop and deleted XP (at least I think XP is deleted).  Then I installed Ubuntu as dual boot with Fedora 15.  Now I want to remove Fedora 15 and leave only Ubuntu (and XP if it is still available).  Can anyone help with the steps to uninstall Fedora?  Please give me simple steps to follow, I'm a nooby.  Thanks! This is a question from the free Harvard online abstract algebra .  I'm posting my solutions here to get some feedback on them.  For a fuller explanation, see  post. This problem is from assignment 5.  a) Prove that the relation $x$ conjugate to $y$ in a group $G$ is an equivalence relation on $G$. b) Describe the elements $a$ whose conjugacy class (= equivalence class) consists of the element $a$ alone.  a) Let $G$ be a group and $R$ be a relation on $G$ defined by $a\sim b$ if $a$ is conjugate to $b$.  Then $a\sim b$ if there is a $g\in G$ such that $a = gbg^{-1}$.  Let $a$ be an element of $G$.  Then $a=eae^{-1}$.  So $a\sim a$ and $R$ is reflexive.  Let $a$ and $b$ be elements of $G$ such that $a\sim b$.  Then there is a $g\in G$ such that $a=gbg^{-1}$.  Then $b=g^{-1}ag$.  Since $g^{-1}\in G$, $b\sim a$.  Hence, $R$ is symmetric.  Let $a,b$, and $c$ be elements of $G$ such that $a\sim b$ and $b\sim c$. Then there are elements $g,g^\prime\in G$ such that $a=gbg^{-1}$ and $b=g^\prime cg^{\prime -1}$.  Then $a=g(g^\prime c g^{\prime -1})g^{-1}=(gg^\prime)c(g^{\prime -1}g^{-1})=(gg^\prime)c(gg^\prime)^{-1}$. Since $gg^\prime\in G$, $a\sim c$.  Hence $R$ is transitive.  Therefore $R$ is an equivalence relation on $G$. b) Let $S$ be the set of elements of $G$ such that, for $s\in S$, $s=gsg^{-1}$ for any $g\in G$.  Then $sg=gs$.  So $S$ is the set of elements that commute with every element of $G$.  In other words, $S$ is the center of $G$. Again, I welcome any critique of my reasoning and/or my style as well as alternative solutions to the problem. Thanks. launch app, capture stdout and stderr in c++ How do I launch an app and capture the output via stdout and maybe stderr?  I am writing an automated build system and I need to capture the output to analyze. I'd like to update the svn repo and grab the revision number so I can move the files in autobuild/revNumber/ if successful. I also would like to build using make and upload the compile text to my server for everyone to see the warnings and errors on a failed build.  I can't find the system() function, but I found the CreateProcess() function on MSDN. I am able to launch what I need but I have no idea how to capture the stderr and stdout.  I notice the process launches separately unless I set a breakpoint and keep my app exiting which it then will keep all the text in my app console window. I would also want to wait until all processes are finished and then scan the data it produced to do any additional operations I need. How do I do any of this? Let $X$ be an arbitrary random variable  takes values in $\{0,1,2,...,10\}$. What are the minimum and  maximum values of variance of random variable $X$? Proper analyses for 2x2 contingency tables So I have multiple questions about the different types of analyses that can be used on a 2x2 contingency table and when different analyses should be used.   To open, I'll note that this stems from my efforts to find the appropriate analyses to run for research using categorical data in a 2x2 contingency table. In my case I have two conditions: control and experimental and within the experimental group there are two items of interest (say, Item A and Item B). In all cases I'm investigating whether an outcome occurs or not: How many experimental participants show the outcome on Item A? How many experimental participants show the outcome on Item B? How many control participants show the outcome? So in addition to comparing Item A with the Control group (A vs. C) and Item B with the Control group (B vs. C), I also want to compare Item A with Item B (A vs. B).   My understanding is that for between-subjects comparisons (e.g., A vs. C   &amp;   B vs. C) a  is traditionally used and that for within-subjects comparisons (e.g., A vs. B) that  is a common choice.   Question 1: is this an accurate understanding of the common choices for statistical tests using 2x2 contingency tables?    My follow-up questions, and where most of my confusion lies, are related to what to do when multiple observed cell counts are low (less than 10). I've explored numerous threads here, the Wikipedia pages for different topics (Yates's correction, Fisher's exact, etc.), a few journal articles, and descriptions in R-packages, but I have found conflicting views.   Some sources indicate that you should use , others say it's out-dated because, in addition to being overly conservative, it was only preferred because the other options were computationally intense.   Others say that you should use , but I've seen additional information suggesting that Fisher's exact test is only appropriate if you know both the row and column totals and that other options (Boschloo, Barnard, etc.) are generally more powerful. However, which of those to use is also not clear.  Finally, even others suggest that the Pearson's $\chi^{2}$ test is appropriate as long as the expected cell counts are not low.   I've seen some indication that these arguments occur for McNemar's test as well (e.g., continuity correction &amp; McNemar's exact test).  Question 2: Is the assumption regarding cell counts about expected cell counts or observed cell counts? If the observed cell counts are low, does that matter to the type of test that should be used?  Question 3: What is an exact test and when should exact tests be used?    In addition to answers to these questions, I would also greatly appreciate any suggestions as to books or articles I can read to learn more about this. Part of my struggle with all of this has been just general difficult finding clear information about these topics and how they relate to one another. Unsized array declaration in a struct If $$\tan(\frac{\pi}{4}+\frac{\theta}{2})=\tan^3(\frac{\pi}{4}+\frac{\alpha}{2})$$, then prove that $$\sin \theta=\frac{3 \sin \alpha+\sin^3 \alpha}{1+3\sin^2 \alpha}$$  I tried using the fact that  $\frac{\cos A}{1-\sin A}=\tan(\frac{\pi}{4}+\frac{A}{2})$ but now not able to eliminate $\cos \alpha$ and $\cos \theta$. How should I proceed? Getting a File's MD5 Checksum in Java I am looking to use Java to get the MD5 checksum of a file.  I was really surprised but I haven't been able to find anything that shows how to get the MD5 checksum of a file.  How is it done? How to understand the definition of vector and tensor? Physics texts like to define vector as something that transform like a vector and tensor as something that transform like a tensor, which is different from the definition in math books. I am having difficulty understanding this kind of definition. To me, it goes like this:   First we have a collection of bases or coordinate systems (do these represent reference frames?) and the transformations between them. A vector/tensor is an assignment of an array of numbers to each basis, and these arrays are related to each other by coordinate transformations.   I am wondering how coordinate systems and transformations are specified.    Do we need all possible coordinate systems and transformations to define a vector space or just a few of them? How to define the concept of basis and coordinate transformation without completing the very notion of vector?