I was wondering if it's possible to upload the .apk file to MySQL database and make em downloadable.   Even if it's possible, would it be a good choice to primarily use the database to handle all the uploaded files? Or a web server is a must needed for this kind of purpose?
So I'm using an app that stores images heavily in the DB. What's your outlook on this? I'm more of a type to store the location in the filesystem, than store it directly in the DB.  What do you think are the pros/cons?
Why don't we allow low reputation users to insert more than two images in their posts? I was searching for privileges one can get after a certain amount of reputation, and I ended up with this question in my mind: Why don't we allow users with low reputation to insert more than two images or links in their posts?  Is it good to make restrictions for them? Let's say someone is going to post a good question and he/she needs to insert three images to explain it properly; because this can't be done the question may become vague or incomplete to answer, and ultimately be flagged by others. Is this a rational decision for those users?  Yes, I believe that restrictions should be there to make a control over new users like for voting privileges but is it good to make restrictions on Questions and Answers?  Here is my question:  Is it decent to restrict new users in such a manner? Scroll to bottom of div? I am creating a chat using Ajax requests and I'm trying to get messages div to scroll to the bottom without much luck. I am wrapping everything in this div: #scroll {     height:400px;     overflow:scroll; }  Is there a way to keep it scrolled to the bottom by default using JS? Is there a way to keep it scrolled to the bottom after an ajax request? How many solutions are there to $x_1 + x_2 + ... + x_5 = 21$? How many solutions are there to the equation      $x_1 + x_2 + x_3 + x_4 + x_5 = 21$    where $x_1, i = 1,2,3,4,5$ is a nonnegative integer such that $0 ≤ x_1 ≤ 3, 1 ≤ x_2 &lt; 4$, and $x_3 ≥ 15$?  I have correctly completed the previous parts of the question but am having trouble with this particular restriction.  The total number of solutions to the equation is $C(25,21) = 12650$.  I have tried to do each restriction individually:  For $0 ≤ x_1 ≤ 3$, I solved this by subtracting the number of solutions when $x_1 ≥ 4$ from the total number of solutions. This is $C(25,21) - C(21,17) = 5985$.  For $1 ≤ x_2 &lt; 4$, I have $C(24,20) - C(21,17) = 5985$.  For $x_3 ≥ 15$, I have $C(10,6) = 210$.  However, the restriction is when these are all together. I am not sure how to proceed. The answer is $106$. $G$ is a finite group such that $|G|=n$. Let $p$ be the smallest prime such that $p|n$. If $H\triangleleft G$ such that $|H|=p$, then prove that $H\subset Z(G)$.  My Work:  Since $|H|$ is a prime $H\cong \mathbb{Z}/(p)$. Hence $H$ is cyclic and abelian. I was stuck afterwards. Can anyone please give me a hint? Using bools in calculations to avoid branches Will having multiple domains improve my seo? What permissions should a udev rule have for a USB device? 644? 755?  For example on Ubuntu I'm looking at this file: /etc/udev/rules.d/99-lpcscrypt.rules Deleting 'garbage' nodes after polygon dissolve I work with QGIS 2.10.1 on Windows 7 (x64). I have dissolved polygons from an attribute value and the polygons geometries being not perfectly joined together, I get some 'garbage' nodes I need to delete. I have tried to edit the layer and using nodes tool, selecting and deleting the nodes, but it seems impossible to do (nodes are not deleted at all!). Any idea on how to process this kind of clean-up?  EDIT : you can  for testing. I got my dad a Logitech LS21 system for Christmas. It's a 2.1 system, but it's recognized in Windows 8 as a 2.0 system (it says there is no subwoofer connected).    How would I go about getting the sub recognized?  It plays some sound now, but it's so quiet you can't hear it without putting your ear right next to it. Why is vote time missing in the SE data dump and SEDE? On company 401k matching. Clarification needed I realized I don't fully understand something. It almost embarrassing to admit.  In 2016 we have 18k max contribution limit for 401k. Does this mean that employee can contribute at most 18k or that total contributions made on behalf of employee should not exceed 18k (company match)  To make is simple, if you make 100k, by contributing 18% you got your limit. But if your company matches 5%, actual contributions will be 18.9k. In the above example, if one wants to maximize benefit should one contribute 18% or less? An Olympiad problem in prime numbers :can we proof that "n" is prime in this case " Let x,n ∈ $\mathbb{N}$  such that :  1+$x^1$+$x^2$+$x^3$+....+$x^{n-1}$ is prime .  Proof that n is prime .  I actually suppose that n isn't prime absurdly so n=p×k such as p is prime ,I also use the $a^n$-$b^n$ formula  and find that $x^k$-1/$x^1$-1 so that means that k=1 and then  n=p which is absurd. Does Anyone has another answer ? How does virtualizing differ from emulation, in terms of structure? Someone told me that a virtualizing program like VirtualBox does not work like an emulator does in the sense that it doesn't emulate registers and uses the actual ones for the virtualized data that are on the CPU. Emulators must emulate the registers since they are mostly to execute software that depends on a foreign environment (e.g. a Genesis emulator needs Motorola 68000's registers and memory addresses, so developer must make these resources available as emulated registers).  My main question is, how is virtualization developed? How do we enable an entire OS to run as a process in a virtual machine, but get it to run independently while still making use of the actual CPU? I only know emulation, not virtualization, so if anyone could help that'd be nice!  PS: I am not asking solely what the difference is, but differences in how they run software. Show that the function $f: S \to \mathbb R$ given by $$f(x,s,t):=-\ln(st - ||x||^2)$$ is convex on $$S := \left\{(x,s,t) \in \mathbb R^n \times \mathbb  R \times \mathbb R: \frac{\|x\|^2}{s}&lt;t, s&gt;0, t&gt;0 \right\}$$   $-\ln(x)$ is a convex monotonic decreasing function, hence we can use composition by showing the inner part is concave. Also we know $-||x||^2$ is concave and $st$ is neither convex nor concave on $S$. Also in $S$ we have $st&gt;||x||^2$ but I was unable to show the convexity of the function as a whole I have a LAMP server with following configuration.  CPU : Intel(R) Xeon(R) CPU   RAM : 32 GB  HDD : 80 GB  Running on virtual environment.  All the things in the server are running smoothly. But I have noticed that the RAM usage is the server is increasing each day without any reason.   This is the current memory usage on my server.  # free -g              total       used       free     shared    buffers     cached Mem:            31         13         17          0          0         10 -/+ buffers/cache:          1         29 Swap:            2          0          2   And you can see the last 8 weeks memory usage below.   And i have executed the following command to find how much memory each process is consuming.  # ps -eo size,pid,user,command --sort -size | awk '{ hr=$1/1024 ; printf("%13.2f Mb ",hr) } { for ( x=4 ; x&lt;=NF ; x++ ) { printf("%s ",$x) } print "" }'          0.00 Mb COMMAND        2253.62 Mb /usr/libexec/mysqld --basedir=/usr --datadir=/var/lib/mysql --user=mysql --pid-file=/var/run/mysqld/mysqld.pid --skip-external-locking --socket=/var/lib/mysql/mysql.sock        1171.66 Mb java -jar /etc/vmagent/bin/VMAgent.jar         138.27 Mb /sbin/audispd         127.75 Mb /usr/sbin/named -u named -c /etc/named.conf -u named -t /var/named/run-root          74.29 Mb auditd          73.03 Mb automount          43.14 Mb /usr/bin/spamd --username=popuser --daemonize --nouser-config --helper-home-dir=/var/qmail --max-children 5 --create-prefs --virtual-config-dir=/var/qmail/mailnames/%d/%l/.spamassassin --pidfile=/var/run/spamd/spamd_full.pid --socketpath=/tmp/spamd_full.sock          43.14 Mb spamd child          43.14 Mb spamd child          37.13 Mb /usr/sbin/httpd          37.02 Mb /usr/sbin/httpd          36.52 Mb /usr/sbin/httpd          36.46 Mb /usr/sbin/httpd          36.23 Mb /usr/sbin/httpd ................   For troubleshooting , i have restarted the MySQL and APACHE servers. But the result was same. Restarting the entire server will fix the issue, but i want to know what is the real issue.  Let me know if you have any idea about this issue.  Thanks,  Arun S What is behind the definitions of work and energy? This is a follow-up question to , and is somehow related to   However, my question does not concern the reviews I receive for the papers I submit, but concerns the reviews I write for papers I have been assigned. Since the whole process is done under confidentiality, it is not clear who owns the copyright on a review I wrote, and what does the review include.   For instance, let us assume that X is member of a PC of a conference Y, and assigns to me a review of a paper Z, written by A and B (assuming it's not a double-blind). Can I publish on my blog: "Here is my review for Y, asked by X, on the paper Z, written by A and B"?   I think that there are two points here:    Is it legal? (for instance, publishing the camera-ready version of a paper might be illegal due to the copyright transfer, would it be also the care here?).  Is it ethical? (who should I ask in order to do so? X? Y? A and B? everybody?).    EDIT: There is been several comments/answer wondering why I would like to publish a review I wrote. To give a bit of background of this question, I believe that the current reviewing system, created when the academic community was small and there was no Internet (i.e. no easy access to information), might not be the best, although clearly working. This is for me a very interesting debate, but somehow out of the scope the Q&amp;A format of Academia SE, which is why I tried to focus on my question on whether it was possible to do so, not if it was the best thing to do in the current system (and just to be clear, I don't plan to do it, but I just like to know what are my options). Anyway, thanks for the answers bringing a different light on this debate.   EDIT 2: After seeing the update in Jeff's answer, I just realised that I didn't make it explicit that I was talking about reviews after the reviewing process. Jeff says that it's ok if the paper is accepted, and although I clearly understand the argument of why I shouldn't publish a review of a rejected paper, the question still holds: by publishing a review of a rejected paper, I publish the information that these authors submitted this paper to this conf/journal, which is supposed to be confidential between the authors and the editors. Would I break any rule by doing so? I want to do:  cat update_via_sed.sh | sed 's/old_name/new_name/' &gt; new_update_via_sed.sh   in my program.  But I want to use variables, e.g.  old_run='old_name_952' new_run='old_name_953'   I have tried using them but the substitution doesn't happen (no error). I have tried:  cat update_via_sed.sh | sed 's/old_run/new_run/' cat update_via_sed.sh | sed 's/$old_run/$new_run/' cat update_via_sed.sh | sed 's/${old_run}/${new_run}/' Continuity of a convex function I'm trying to solve the following problem:  Let $f:K\rightarrow \mathbb{R} $, $f$ convex and $K \subseteq \mathbb{R}^n$ convex. Then $f$ is continuous on $K$.   I have proved the only case $n=1$, but for an arbitrary $n$?? How do you open a command line? How do you access the command line or run option to put the commands into the system?