When I make any data transfer process (from computer to usb), after a couple of seconds file transfer process freezes. It be normal after a few minutes later but again freezes. If there would no problem, copy process will be fast. Unlikely my hard-disk works without any problem. Also Flash-disk hasn't got any problem. -I disgust to say that- USB works fine in other OSes.  Note: I am using 3.0 port and 3.0 USB-Driver. I have no 2.0 port on my laptop.
Yesterday I was copying a single, 8 GB file to a USB with a slow, 7 MB/s write speed, while my RAM is 3 GB. While copying the system froze, to the point where I couldn't even move the cursor.  I managed to log into the text console, and ran iotop, it showed that a process named kswapd0 was taking 99.99% of IO.  Are there workarounds so copying a large file doesn't make my system unusable?
Distribution of Dark Matter around galaxies It is well-known that measurements of the velocity profile in galaxies are not compatible with Newtonian laws. A way to circumvent the problem is to assume that galaxies are surrounded by a spherical halo of Dark Matter. The density of mass of this Dark Matter can then be computed from the velocity profile with Newton's laws.   My question is the following: the formation of a galaxy involves essentially only the gravitational interaction. According to Newton (and General Relativity too), the trajectory of a particle does not depend on its mass. As a consequence, I do not understand how usual matter and Dark Matter could have followed different trajectories leading to such different mass distributions nowadays. Can somebody explain this (apparent) paradox ? Who took care of Naruto when he was young? In episode 350, we see that the Third Hokage took on to take care of Naruto. But towards the beginning of the anime Naruto is seen to be living alone.   Did Naruto live with the Third? If so, why did he leave there? How does centrifugal force work? I know what centrifugal force is, but how does it work? Why are things forced to the outside? Can't disable windows 10 PIN complexity I recently linked my Microsoft Office account to my school to have access to Office for students. Right after linking my account, I couldn't login to my computer again with my 4-digit pin code and got the message: "your organization has set the following pin code requirements. Your pincode has to be at least 6 digits long."   I had to change my pincode but I want to change it back to my original 4-digit one. Some internet research has made me enable gpedit.msc, but when I try to find the PIN complexity setting in gpedit (Computer Configuration\Administrative Templates\System\PIN Complexity) it just isnt't there.   Another possible path in gpedit I found on the internet to do this was: Computer Configuration > Administrative Templates > Windows Components > Windows Hello for Business > PIN Complexity, but that also didn't work as I don't have "Windows Hello for Business"   I also tried resetting my computer to the date before I joined my 'organization', but that didn't work either.   Does anyone have an idea how I can resolve this issue? Disable the activation of the menu bar when Alt is pressed in Windows 7 In Windows 7 how can I disable the function that activates the menu bar when Alt is pressed?  Are there some registry values to modify this behaviour? How to delete all music on my iPhone How do I delete all the music on my iPhone.  I tried doing it through iTunes but it says my collection is not managed by iTunes and I don't want to erase and sync because all my apps are nicely backed up and sorted with iTunes.  I have only seen a way of deleting song by song on the phone. Will two-letter font style commands (\bf , \it , …) ever be resurrected in LaTeX? I understand that \bf and \it are now obsolete in LaTeX and that \textbf and \textit are proper, as they produce more sophisticated (in particular, cumulative and properly kerned) changes to font style. I have read the  and I understand the rules and their reasons, as well as the several other commands that are affected.  However, I find it convenient to use LaTeX for notetaking during lectures, and in that rushed environment, shortening a command by any number of keystrokes helps keep me from falling behind. \bf and its two-letter kin are still very useful to me for that reason, and once a presentation is finished I can go through and replace all appearances of \bf et al. with \textbf et al.  My question is this: is there a plan eventually to replace the short font style commands like \bf with the implementations of \textbf etc. some day, or should I expect \bf always to remain in existence but obsolete, for reasons of backward compatibility with original TeX? Original TeX has been greatly improved on in countless ways, but in the heat of transcription I sometimes miss its conciseness. This is a nice problem on series convergence that I recently stumbled upon. Given a non-negative sequence of real numbers $(a_n)$ such that $$\sum_{n=1}^\infty a_n &lt; \infty,$$ show that there exists a non-decreasing sequence of non-negative numbers $b_n$ such that $$b_n \to \infty \quad\text{ and } \quad \sum_{n=1}^\infty a_n b_n &lt; \infty.$$ In other words, for every convergent series with non-negative terms, there is another convergent series with "substantially larger" terms.  I have a solution (see below), but maybe someone else has a different, simpler, and/or more elegant solution. Would raising the review limit help with the Close Votes queue? Eigenvalues of a matrix whose square equals its transpose Let $A$ be a $n\times n$ matrix with $A^2=A^t$. Show that every real eigen value of $A$ is either $ 0$ or $1$ Bounding lines around tax nodes I am trying to draw lines around a number of nodes. I very much like the definition of \convexpath definition given , but it is not working well on my setup (MacTex 2014 with all available updates).   I tried to compile , but what I get is the following, which is clearly not what I should be getting. Any ideas would be much appreciated. Alice has a secp256k1 key pair that she used some time ago when she communicated with Bob. Bob can no longer user secp256k1 but he only uses ed25519 instead.  Is there a secure algorithm that Bob can use to derive an ed25519 pubkey from original Alice's secp256k1 pub key and also Alice can derive the matching ed25519 private key from her original secp256k1 private key such that they can communicate securely via ed25519 encrypted messages?  Thanks! Is there a command like "watch" or "inotifywait" on the Mac? How do I install the latest stable version of Firefox? I want to install the latest Firefox on my Ubuntu (64bit) box.  What is the best way to do this? Is there a specific update site or should I download the binaries manually? If doing manually, in which directory should I put the files? In my home directory, or is there a better place? ROC vs Precision-recall curves on imbalanced dataset I just finished reading  discussion. They argue that PR AUC is better than ROC AUC on imbalanced dataset.   For example, we have 10 samples in test dataset. 9 samples are positive and 1 is negative. We have a terrible model which predicts everything positive. Thus, we will have a metric that TP = 9, FP = 1, TN = 0, FN = 0.  Then, Precision = 0.9, Recall = 1.0. The precision and recall are both very high, but we have a poor classifier.  On the other hand, TPR = TP/(TP+FN) = 1.0, FPR = FP/(FP+TN) = 1.0. Because the FPR is very high, we can identify that this is not a good classifier.  Clearly, ROC is better than PR on imbalanced datasets. Can somebody explain why PR is better? Why does $PSL(2,\mathbb C)\cong PGL(2,\mathbb C)$ but $PSL(2,\mathbb R) \not\cong PGL(2,\mathbb R)$? Why does $PSL(2,\mathbb C)\cong PGL(2,\mathbb C)$ but $PSL(2,\mathbb R) \not\cong PGL(2,\mathbb R)$? Syntax highlighting with less, trouble with lexer I have installed python-pygments and using it for syntax highlighting with less as described by mankoff  I put a function in my .bashrc  cless () {     pygmentize -f terminal "$1" | less -R }   it is enabling syntax highlighting with less. But when I am going to open a file like /etc/fstab or /etc/apt/apt.conf a error saying  Error: no lexer for filename '/etc/apt/apt.conf' found   I found option to show pygmentize the lexer with -l at this . But what will be the appropriate lexer for such files? and how to use it? I have tried to dig around for this, but I can't find a way (other than stepping one by one through past reviews) to see what proportion of my review decisions match the eventual outcome of the review.  This stat would give me confidence that I'm in line with the review guidance and not becoming too lenient in my old age. If it gets too low, I can then double check individual reviews to find out why I'm missing the mark. In the middle of touching up a new texture, I pressed save and suddenly my textures all turned black on the model and UV texture - just vanished.  I tried reopening the file in another instance of Blender, I tried to CtrlZ too and it just did this weird patchy thing on my texture.   How do I recover it and what did I do wrong? Theorem numbering