I am a novice when it comes to photography. But I have a picture that I would love to submit to a photo comp. Their specifications are: have suitable resolution to be printed between 596mm x 422mm (A2) and 841mm (w) x 1189mm (h) (A0) I tried to increase the resolution on photoshop and ended up with these numbers: Image size 1.84 M - With 644 pixels - height 1000 pixels - resolution 300 pixel an inch   Could any let me know if these dimensions are acceptable?
What size images do I need for common print sizes, such as wallet size, 8x10, and 16x20?  Is there a general formula?  How could that size change if, for example, a 16x20 was printed on canvas rather than photopaper?
Convergence of the series $\sum a_n$ implies the convergence of $\sum \frac{\sqrt a_n}{n}$, if $a_n>0$ I need help to solve following problem from Rudin's Mathematical analysis book:    Convergence of the series $\sum a_n$  implies the convergence of $\sum \dfrac{\sqrt {a_n}}{n}$, if $a_n&gt;0$  I tried to construct a suitable convergence sequence $b_n$ such that $\sum b_n$ converges and $a_n \leq b_n$ but, I am not able to find such sequence $b_n$ .  Thanks for the help and sugestions. Why does a light object appear lighter in your peripheral vision when it's dark? So, I am not sure I can reproduce it via images, but the steps are:  1) At night, open a window and have a look at the surface of the earth  2) Suppose there's an object that reflects a tiny amount of light  3) When you actually try to focus your eyes at this object, you either don't see anything (depends on the amount of light it reflects) or you can hardly see it  4) When you focus your eyes on something that is 3-10 metres away, you can easily see this object with your ambient vision. Not the details, but it seems that it reflects more light.   Why does it happen? Use Unity API from another Thread or call a function in the main Thread I would like to use pgfplots to create a figure where I plot curves that have a recursive formula. I tried a very simple case that uses the declare function command to see whether this is possible, and I can't compile (TeX capacity exceeded). Is it even possible to do this?  \documentclass{standalone}  \usepackage{pgfplots}  \begin{document}  \begin{tikzpicture}[   declare function={test(\p)=ifthenelse(\p&gt;1, test(\p-1), 0.5);}, ]     \begin{axis}[]     % use TeX as calculator:     \addplot [mark=none] {x};     \addplot [mark=none] {test(0)};     \end{axis} \end{tikzpicture}  \end{document} django manytomanyfield .add() method Is there a systematic way to obtain all conserved quantities of a system? I'd like to know whether, given a system, there's a way to obtain all the conserved quantities. For instance if the system consists of electric and magnetic fields, the fields must satisfy Maxwell's equations. These equations are invariant under many transformations (Lorentz transformation, rotations, spatial and temporal translations, etc. By the way is there a way, maybe from group theory, to find all the possible transformations that leaves the equation(s) invariant?) which imply as many conserved quantities thanks to Noether's theorem. In wikipedia I can see an equation that seems to give all the conserved quantities () but it involves the Lagrangian and I'm not sure whether the formula is valid for all systems whose Lagrangian is possible to obtain. Keen eye for detail (or details?) Which one is correct? "To have a keen eye for detail" or "To have a keen eye for details"? I am having problems starting my Apache server, because port 443 is already in use.  It turns out, the system process (PID 4) uses the port 443. I don't have IIS installed, the services.msc shows (predictably) no Exchange server running, nor WWW-Services, nor IIS. I have no idea how to find out what service uses that port, short of just disabling each service one after the other, and I am not even sure that would help.  I would be grateful if someone could point me towards how I can get my SSL port back, thank you :)  P.S.: Of course "just switch Apache to another port for SSL" would solve the problem of not being able to start Apache. But I'd still like to know what is so insistent about hogging port 443. :)    I by now took the 'hard route' and disabled services one after the other. It turned out that the "Routing and RAS" service was the culprit.  Thank you all for the valuable input and the new tools in the combat against "WTF does my system do now?". Zombie process using 100% CPU A zombie process, which should not be using any resources (RAM and CPU), is hogging up an entire core on my 8-core 64-bit Ubuntu 11.10 Desktop installation.  This is the output of ps -el|grep Z:  F S   UID   PID  PPID  C PRI  NI ADDR SZ WCHAN  TTY          TIME CMD 0 Z  1000 10317     1 99  80   0 -     0 exit   ?        19:27:15 java &lt;defunct&gt;   ... and here is an excerpt from top:    PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND                                                                                                                                                 10317 deltik    20   0     0    0    0 Z  100  0.0   1170:17 java &lt;defunct&gt;  1424 root      20   0  612m 193m 158m S   14  2.4 287:17.11 Xorg 12580 deltik    20   0  710m 135m  46m S    5  1.7  27:31.07 compiz   This is how the zombie process came to existence:   I opened a Java JAR called . This launcher downloads another JAR file to ~/.minecraft/bin/minecraft.jar That JAR was executing when I locked my computer with xscreensaver. Then, I entered my password to unlock the computer, and I saw that the Minecraft window was frozen. I tried killing it (PID 10317) with gnome-system-monitor. It became a zombie. kill -9 10317 was ineffective. xkill only closed the window titled "Minecraft"; it didn't close the underlying java process.   Relevant information:   The graphics driver is FGLRX, and it has caused notorious issues with  of  and , including sometimes high CPU usage of Xorg and compiz.   I want to know:   What way is there to destroy this process of java without restarting, if any? Why is this issue happening? What can I do to prevent this issue from happening again? How to identify "deictic center" for distinguishing "come" & "go"? Read this paragraph from this    My question is:  How to identify "deictic center" for distinguishing "come" &amp; "go"?  Let say I am at home &amp; I say "I am going to the zoo this evening", so the "deictic center" in this case is my home &amp; I move away my "deictic center".  But let say my friend Tom &amp; I currently at my home &amp; Tom said "Are you Coming to the zoo to see the lion?" &amp; I said "Ok, I am coming to the zoo this evening". So, the "deictic center" in this case is "the zoo" &amp; we move towards the "deictic center" (ie the zoo).  It feels like it is very arbitrary.  Note: See this , it said the selection of "deictic center" could be due to sympathy &amp; politeness. Removing file / folder link after using "Save As..." then "Web Page, complete" When you right-click save-as a web page in FF, the page is saved along with a folder containing any associated media that page needs (images, js, etc).  My problem is that I want to reorganise the associated media folder, but wherever I move this folder, the saved .html file is moved as well. ARGH!   I can rename each folder, which breaks the "link" between html file and media folder, but there must be a cleaner way to do it. Does anyone else know? The Aleph numbers and infinity in calculus. Leaving values blank if not passed in str.format When a vehicle makes a turn, the two front wheels trace out two arcs as shown in the figure below. The wheel facing towards the inside of the turn has a steering angle that is greater than that of the outer wheel. This is necessary to ensure that both front wheels smoothly trace out two arcs, which have the same center, otherwise the front wheels will skid on the ground during the turn.   During a turn, do the rear wheels necessarily trace out the same arcs as the front wheels? How do I make ditto marks? Clear up confusion about the meaning of entropy So I though, and was told, that entropy is the amount of disorder in a system. Specifically the example of heat flow and it flows to maximize entropy. To me this seemed odd. This seemed more ordered to me, from two things (hot and cold) to one thing (lukewarm).   So as I have read today on wikipedia        In recent years the long-standing use of term "disorder" to discuss   entropy has met with some criticism.[20][21][22]      When considered at a microscopic level, the term disorder may quite   correctly suggest an increased range of accessible possibilities; but   this may result in confusion because, at the macroscopic level of   everyday perception, a higher entropy state may appear more homogenous   (more even, or more smoothly mixed) apparently in diametric opposition   to its description as being "more disordered". Thus for example there   may be dissonance at equilibrium being equated with "perfect internal   disorder"; or the mixing of milk in coffee being described as a   transition from an ordered state to a disordered state.      It has to be stressed, therefore, that "disorder", as used in a   thermodynamic sense, relates to a full microscopic description of the   system, rather than its apparent macroscopic properties. Many popular   chemistry textbooks in recent editions increasingly have tended to   instead present entropy through the idea of energy dispersal, which is   a dominant contribution to entropy in most everyday situations.    So what this is saying basically many people mistake the macroscopic outcome of entropy in the same manner as I have above. Seemingly two dissimilar things combining and becoming one.   They say to understand it microscopically. But this still is odd to me, take for example the particles in a box, when they come to thermal equilibrium they are said to have the most entropy they can within their system (from wiki again)     Entropy – in thermodynamics, a parameter representing the state of   disorder of a system at the atomic, ionic, or molecular level; the   greater the disorder the higher the entropy.[7]   What is disorder in the molecular sense I guess is my question. When the particles all come to thermal equilibrium they all seem to be uniform, which I equate with ordering.  I feel disorder in the molecular sense would be fast moving particles, making a mind boggling amount of interactions with each other. Such as in a hot gas, hot gas seems super disordered, but put cold gas in thermal contact with it, let them come to thermal equilibrium, and now they are more ordered!? I've got to send a bulk email out to a bunch of people in reply to emails they sent me. I've got all the original emails stored in a single outlook folder. I want to extract all of the reply addresses from the emails in that folder so I can send an email to all of them.  The article  shows you how to export the FROM address of these emails, however a large amount of them came from a web service that sends emails 'on behalf of' the person I'm trying to mail to. So I need the reply-to address, and the export wizard doesn't do that.  Does anyone have a tip on how to do this? This is Outlook 2007 on Exchange 2010. What does "javascript:void(0)" mean? An explanation of Hawking Radiation Lie bracket for Lie algebra of $SO(n,m)$ How does one show that the bracket of elements in the Lie algebra of $SO(n,m)$ is given by  $$[J_{ab},J_{cd}]  ~=~ i(\eta_{ad} J_{bc} + \eta_{bc} J_{ad} - \eta_{ac} J_{bd} - \eta_{bd}J_{ac}),$$  where $\eta$ has is the definite symmetric form with signature $(n,m)$?